Lectures

Question 1

3 components of Communication Systems in body

Answer 1

1. Nervous system
2. Endocrine system
3. Immune system

three most important communication systems in body

these symptoms are interconnected

Question 2

forms of communication between nervous system and endocrine system

Answer 2

1. hormones
2. neurotransmitters

Question 3

forms of communication between endocrine system and immune system

Answer 3

1. hormones
2. cytokines

Question 4

forms of communication between nervous system and immune system

Answer 4

1. cytokines
2. neurotransmitters

Question 5

nervous system splits into…

Answer 5

central nervous system and peripheral nervous system

Question 6

central nervous system

Answer 6

division of the nervous system

structures encased in bone

1. brain (cranium)
2. spinal cord

Question 7

peripheral nervous system

Answer 7

division of the nervous system

1. autonomic system
2. somatic system

Question 8

autonomic nervous system

Answer 8

responsible for INVOLUNTARY control of the body

Question 9

somatic nervous system

Answer 9

responsible for CONSCIOUS PERCEPTION and VOLUNTARY MOTOR RESPONSES

Question 10

autonomic system splits into…

Answer 10

1. sympathetic
   - fight or flight
2. parasympathetic
   - rest and digest

Question 11

what kind of neurons for parasympathetic system?

Answer 11

cholinergic

Question 12

what kind of neurotransmitter for sympathetic system?

Answer 12

norepinephrine

Question 13

somatic nervous system

Answer 13

subdivision of peripheral nervous system

allows you to move and control muscles

feeds info from 4 senses to brain

2 pathways

Question 14

four senses whose info are carried by the somatic NS

Answer 14

smell
sound
taste
touch

Question 15

somatic NS: two pathways of info

Answer 15

1. afferent
2. efferent

Question 16

afferent pathway

Answer 16

carries info from SENSORY receptors to the CNS

Question 17

efferent pathway

Answer 17

carries MOTOR INFO away from the CNS to the MUSCLES/GLANDS

Question 18

classical definition of behaviour

Answer 18

behaviour results from 3 interacting components

Question 19

hormones can effect which of the components of behaviour?

Answer 19

all three (input, CNS or output)

Question 19

3 interacting components which result in behaviour

Answer 19

1. input system/sensorial stimulus (internal or external)
2. central NS
3. output system/peripheral NS (effectors)

Question 20

superior

Answer 20

above

Question 21

inferior

Answer 21

below

Question 22

rostral

Answer 22

front

Question 23

caudal

Answer 23

back

Question 24

anterior

Answer 24

in front

Question 25

posterior

Answer 25

behind

Question 26

dorsal

Answer 26

back

Question 27

ventral

Answer 27

front/belly

Question 28

3 axes we use to slice brain

Answer 28

1. coronal
2. sagittal
3. horizontal

Question 29

coronal slice

Answer 29

divides front and back of brain

Question 30

sagittal slice

Answer 30

splits brain into the two hemispheres (along the longitudinal fissure)

Question 31

horizontal slice

Answer 31

divides top and bottom of brain

Question 32

entire central nervous system comes from what in the fetus?

Answer 32

neural tube

entire brain comes from this tube

Question 33

neural tube develops when

Answer 33

3 weeks

Question 34

3 vesicles of the neural tube

Answer 34

forebrain

midbrain

hindbrain

Question 35

later on in development, the forebrain divides into…

Answer 35

telencephalon (cerebrum)

diencephalon (lower structures)

Question 36

telencephalon is composed of…

Answer 36

1. cortex
2. limbic system
3. basal ganglia

Question 37

diencephalon

Answer 37

1. thalamus
2. hypothalamus

Question 38

most of the brain is composed of the…

Answer 38

cerebral cortex

Question 39

cerebral cortex functions

Answer 39

consciousness, thought, emotion, reasoning, language, memory

Question 40

cerebral cortex is subdivided into…

Answer 40

4 lobes

frontal, temporal, parietal, occipital

Question 41

corpus callosum

Answer 41

connects hemispheres of brain

Question 42

cortex is how thick

Answer 42

3 mm

covers both hemispheres

Question 43

cortex is composed of…

Answer 43

grey matter

bodies of the neural cells

Question 44

white matter

Answer 44

axons

means that all the grey matter (cell bodies) are connected all over the brain by the white matter (axons)

Question 45

DTI

Answer 45

uses water to show the neuron connections and their activity

Question 46

frontal lobe 4 main functions

Answer 46

1. reasoning/executive functioning (PFC)
2. motor control (motor cortex)
3. emotion
4. language (Broca’s area)

Question 47

where is the motor cortex?

Answer 47

PFC

precentral gyrus

Question 48

Broca’s area

Answer 48

essential for language production

in frontal lobe

Question 49

early evidence of importance of frontal lobe in behaviour regulation

Answer 49

case of Phineas Gage

Question 50

Phineas Gage

Answer 50

railroad construction accident survivor

large iron rod was driven completely through his head

Question 51

where were the lesions in Phineas Gage’s brain?

Answer 51

widespread lesion of LEFT FRONTAL LOBE

Question 52

reported effects of Gage’s lesions

Answer 52

affected personality and behaviour

Question 53

parietal lobe

Answer 53

processes sensory info of the body

contains SOMATOSENSORY CORTEX

Question 54

somatosensory cortex alternative name

Answer 54

postcentral gyrus

Question 55

somatosensory cortex is organized in what manner?

Answer 55

topographically

ie. cortical homunculus

Question 56

temporal lobe main function, and secondary ones

Answer 56

main: processing auditory signals

secondary: learning, memory, language, integrates info from other brain regions

Question 57

occipital lobe

Answer 57

at back of head

interprets VISUAL info

also involved in balance - cerebellum

Question 58

boxing anecdote occipital lobe

Answer 58

illegal in boxing to punch at the back of the head

because it can cause loss of vision

Question 59

subcortical regions

Answer 59

regions other than the frontal, parietal, temporal, and occipital lobes are SUBCORTICAL

Question 60

4 subcortical regions

Answer 60

1. amygdala (fear/anxiety)
2. hippocampus (learning/memory)
3. hypothalamus (homeostasis - connection with endocrine system)
4. thalamus (relay centre of brain)

Question 61

limbic system is composed of…

Answer 61

amygdala, hippocampus, hypothalamus, thalamus

Question 62

amygdala has lots of receptors for…

Answer 62

cortisol

reacts to stress

Question 63

limbic system is where our ____ originate

Answer 63

initial emotional responses

Question 64

limbic system is located where

Answer 64

between brainstem and neocortex

acts like a bridge between these two areas

Question 65

has a consensus been reached on what parts of the brain compose the limbic system?

Answer 65

not really

but it’s agreed upon that the amygdala, hippocampus, thalamus and hypothalamus are part of it

Question 66

what is the structure behind our body FEELING the emotions that we experience?

Answer 66

hypothalamus

Question 67

limbic system in reaction to scary movie

Answer 67

watching movie

1. hypothalamus receives a signal from the amygdala that something frightening is being presented
2. hypothalamus triggers the fear/fight or flight response

Question 68

“the master regulator of the endocrine system”

Answer 68

the hypothalamus

Question 69

if hippocampus is damaged…

Answer 69

can’t convert STM to LTM (anterograde amnesia)

people feel less fear, hyper-sexuality and mellowness

Question 70

SM’s amygdala was damaged…

Answer 70

and she couldn’t feel fear as a result

Question 71

case of HM

Answer 71

suffered from seizures

removed hippocampus in attempt to treat it

function of hippocampus was unknown at the time

seizures stopped, IQ improved

ONE PROBLEM: his memory was gone
- lost most memories of past
- short term mem couldn’t be consolidated

couldn’t form new memories

but could keep it in working memory

Question 72

before HM, memory was thought to be…

Answer 72

monolithic and stored in the same place in the brain

HM paved way to distinction between STM and LTM

and idea that diff mems are stored in diff areas

Question 73

hippocampus main function

Answer 73

memory consolidation

STM to LTM

Question 74

procedural memory relies more on which two structures?

Answer 74

1. basal ganglia
2. cerebellum

^these two structures were both intact in HM’s brain

Question 75

2 main parts of the midbrain

Answer 75

substantia nigra

ventral tegmental area

(located deep within the brain)

Question 76

midbrain is responsible for what three main things?

Answer 76

mood, reward and addiction

Question 77

hindbrain 3 parts

Answer 77

1. medulla
2. pons
3. cerebellum

Question 78

medulla

Answer 78

controls automatic processes of ANS

blood, breathing, heart rate

Question 79

pons

Answer 79

connects hindbrain to rest of brain

means “bridge”

Question 80

cerebellum

Answer 80

receives msgs from joints and ear structures

controls balance

some procedural memory

Question 81

two types of neuronal cells

Answer 81

1. neurons
2. glial cells

Question 82

glial cells comes from what word

Answer 82

Greek word for “glue”

Question 83

glial cells were initially thought to only…

Answer 83

1. hold neurons in place
2. act as supportive cells

Question 84

now we know that glial cells have a variety of functions, such as…

Answer 84

1. providing support to neurons
2. repairing damage
3. fighting infections
4. influencing neurotransmission

Question 85

3 types of glial cells

Answer 85

1. microglia
2. oligodendrocyte
3. astrocyte

Question 86

microglia

Answer 86

immune response

homeostasis

supporting neuronal function

Question 87

oligodendrocyte

Answer 87

produce myelin sheaths that wrap around axons

nurturing and sustaining the environment around axons

Question 88

astrocyte

Answer 88

neural support

repair damage

regulate neuronal communication

Question 89

in PNS, oligodendrocytes are called…

Answer 89

schwann cells

Question 90

in PNS, astrocytes are called…

Answer 90

satellite cells

Question 91

neurons are _______ cells

Answer 91

excitable

can be excited in certain situations

Question 92

dendrite

Answer 92

serve as input sites where SIGNALS ARE RECEIVED from other neurons

are different at diff ages

old people have less, and shorter, dendritic spines

Question 93

stress and dendrites

Answer 93

stress can reduce number of dendritic spines

Question 94

each dendritic spine is postsynaptic to…

Answer 94

one or two axon terminals

Question 95

intellectual disability and dendritic spines

Answer 95

spines have diff (abnormal) formations in intellectual disabilities

Question 96

axons

Answer 96

longest projections from the soma

end at multiple terminal buttons

Question 97

terminal buttons

Answer 97

where the signal (action potential) finishes

where the neuron communicates with another neuron/other cells

Question 98

soma

Answer 98

central part of neuron

Question 99

soma contains…

Answer 99

watery fluid called CYTOSOL

Question 100

cytosol

Answer 100

watery fluid inside the cell

salty, potassium rich solution

Question 101

cytosol is separated from the outside of the cell by the…

Answer 101

neuronal membrane

Question 102

membrane-enclosed structures within the soma

Answer 102

organelles (ribosomes, proteins)

cell body of neuron contains SAME organelles found in all animal cells

Question 103

nucleus

Answer 103

produces proteins

spherical, centrally located part of the neuron cell

Question 104

nucleus is contained within a…

Answer 104

DOUBLE MEMBRANE called the nuclear envelope

Question 105

nuclear envelope

Answer 105

the double membrane that contains the nucleus

it’s perforated by POREES

Question 106

some hormones act within the neuron nucleus and…

Answer 106

have TRANSCRIPTIONAL properties

Question 107

nucleus and hormones

Answer 107

some hormones affect the nucleus

bind to receptors

GENE TRANSCRIPTION to create proteins

Question 108

gene transcription

Answer 108

1. RNA molecules are synthesized by RNA polymerase
2. then processed into mRNA to carry genetic instructions for protein assembly from nucleus to cytoplasm
3. transcription is initiated at promoter region of gene and stopped at terminator region
4. initial RNA must be spliced to remove the introns that don’t code for protein
5. then are exported from nucleus

Question 109

membrane

Answer 109

1. serves as BARRIER to enclose the cytoplasm inside the neuron
2. excludes certain substances that float in the fluid that bathes the neuron
3. various types of proteins are embedded within the neuron cell membrane

Question 110

4 proteins embedded within the membrane of neurons

Answer 110

1. ion channels
2. transporters
3. receptors
4. enzymes

Question 111

ion channels

Answer 111

allow the passage of ions (ie. sodium, potassium, calcium) in and out of the cell

facilitates nerve impulse transmission

Question 112

transporters

Answer 112

assist in the movement of molecules and ions across the membrane

Question 113

receptors

Answer 113

bind to specific neurotransmitters or signalling molecules, initiating cellular responses

Question 114

enzymes

Answer 114

catalyze specific chemical reactions crucial for cellular functions

Question 115

function of neurons cannot be understood without understanding structure and function of…

Answer 115

membrane and its associated proteins

Question 116

membrane is important in maintaining difference in…

Answer 116

electrical charge

Question 117

resting membrane potential

Answer 117

cell is at rest

not generating impulses

inside the cell = negative
outside the cell = positive

Question 118

how do neurons maintain the difference in electrical charge?

Answer 118

ion channels

sodium, potassium and chloride

sodium and potassium = positively charged

chloride = negatively charged

Question 119

sodium-potassium pump

Answer 119

uses energy (via ATP -> ADP)

to constantly pump 3 sodium ions OUT of the cell

and 2 potassium ions INTO the cell

uses energy to constantly maintain the difference in electrical charge

Question 120

sodium-potassium pump helps to keep the electrical charge inside the cell…

Answer 120

less positive than the electrical charge outside the cell

so more negative inside the cell

Question 121

what percentage of brain’s energy is used to maintain the electrical diff for neurons?

Answer 121

60-70%

very energy-demanding

Question 122

what happens when neuron receives a stimulus?

Answer 122

rapid reversal of the resting state

the membrane becomes positively charged

Question 123

the _______ and _______ of action potentials constitute the code used by neurons to transfer info from one location to another

Answer 123

FREQUENCY and PATTERN

Question 124

in resting state, charge of inside of cell is

Answer 124

-70 mV

while the outside is positive

Question 125

when neuron receives stimulus, what channels open?

Answer 125

sodium channels

because sodium ions are more concentrated OUTSIDE the cell, they flow inside the cell (concentration gradient)

because sodium is positive, the membrane DEPOLARIZES

Question 126

repolarization

Answer 126

cell depolarizes with the stimulus

sodium ions enter the cell and make the inside positively charged

reaches a peak of 50 mV

then there is a process of REPOLARIZATION where the neuron returns to resting state

Question 127

during depolarization, what peak charge does the inside of the cell reach?

Answer 127

50 mV

Question 128

hyperpolarization

Answer 128

when neuron is too negative

cannot depolarize/fire in this state

refractory period

Question 129

what channels open during repolarization?

Answer 129

potassium channels

potassium leaves the cell (because of concentration gradient) until it reaches its resting state of -70 mV once more

Question 130

how does neuron return to resting potential after firing?

Answer 130

sodium-potassium pump

brings 2 potassiums into cell

brings 3 sodiums out of cell

now ready for another action potential

Question 131

unmyelinated versus myelinated axons

Answer 131

myelinated with nodes of ranvier = faster transmission

signal/action potential jumps from node to node

Question 132

5 action potential properties

Answer 132

1. all same size
2. all same duration
3. don’t diminish as they move down the axon
4. frequency and pattern of action potentials constitute the code used by neurons to transfer info from one location to another
5. very rapid - 100 times faster than blink of an eye

Question 133

how long do action potentials last?

Answer 133

about 2 milliseconds

Question 134

at the axon hillock…

Answer 134

action potentials undergo summation

potentially is enough to generate the release of neurotransmitters

Question 135

neural firing chain of 6 events

Answer 135

1. neurotransmitter release
2. receptor binding
3. ion channels open/close
4. conductance change causes current flow
5. postsynaptic potential changes
6. postynaptic ions excited or inhibited

Question 136

ionotropic vs metabotropic

Answer 136

ionotropic: ligand-gated ion channels

metabotropic: G-protein coupled receptors

Question 137

4 NT pathways

Answer 137

DANS

1. dopamine
2. acetylcholine
3. norepinephrine
4. serotonin

NTs occur in specific pathways, aren’t just randomly distributed across the cortex

Question 138

what creates the potential in a cell?

Answer 138

the -70 mV difference between the inside and the outside of the cell

this difference in charge creates the potential for action and for rest as well

Question 139

communication between neurons and glands is very _____, while communication between glands is very _____

Answer 139

fast

slow (because the hormone must travel through the bloodstream to reach the target)

Question 140

behavioural endocrinology is the study of…

Answer 140

scientific study of the BIDIRECTIONAL interactions between hormones and behaviour

hormones can affect behaviour, and behaviour can influence hormones

Question 141

3 things that hormones affect which indirectly impact behaviour

Answer 141

they affect individuals’:

1. sensory systems
2. integrators
3. effectors (output systems)

^all three of these are important for behaviour, and hormones affect all of them

Question 142

hormone

Answer 142

organic chemical messenger

released from endocrine cells

travels through blood system to interact with cells via very specific receptors

Question 143

endocrine glands

Answer 143

ductless glands from which hormones are released into the blood stream

release hormones in response to specific physiological signals

Question 144

hormones do what to influence probability of behaviour

Answer 144

1. they change gene expression
2. or they change rate of cellular function

these two things affect behaviour by increasing the probability that a given behaviour will occur in the presence of a specific stimulus

Question 145

endocrine cells versus endocrine glands

Answer 145

endocrine cells: ie. fat
- fat releases hormones

endocrine glands:
- produce and release hormones
- can be released by direct innervations or if something binds to the gland (cascade)

Question 146

the effects of hormones are notable not only in behaviour…

Answer 146

but also in several human ATTRIBUTES and CHARACTERISTICS

Question 147

3 examples of how hormones affect other human attributes and characteristics

Answer 147

1. Lance Armstrong admittedly used EPO, blood transfusions, testosterone and corticosteroids when competing
2. Testosterone treatment
3. Messi had Growth Hormone Deficiency (GHD) and received GHD injections

Question 148

testosterone causes…

Answer 148

gain of body mass

higher levels of aggression/paranoia

messes with feedback mechanisms between communication between brain and testes

Question 149

historical roots of behavioural endocrinology

Answer 149

remarkably multidisciplinary from the very beginning

relationships among endocrine glands, their hormone products and behaviour have been implicitly recognized for centuries

Question 150

example of relationship between endocrine glands, their hormone products and behaviour

Answer 150

male sex organs (testes) produce and secrete a hormone called testosterone that influences sexual behaviour, aggression, territoriality, as well as other behaviours that differentiate males from females

Question 151

Alessandro Moreschi

Answer 151

the last known castrato

removing testes causes behavioural changes

Europe in times past - if you were a young boy with a good voice, the Church might castrate you to keep your voice high (castratos)

childlike voice

Question 152

first method used to determine if a gland affects a behaviour

Answer 152

ablation and replacement

Question 153

steps of ablation and replacement

Answer 153

1. gland that is suspected to be the source of the hormone affecting behaviour is surgically removed
2. effects on behaviour are observed
3. hormone is replaced by re-implantation, injection of an extract from the gland, or injecting a purified hormone
4. determination is made whether the observed consequences of removal are reversed by the hormonal replacement therapy

Question 154

Berthold’s experiment

Answer 154

first ever hormones and behaviour experiment

had three groups of chicks

group 1: castrated
group 2: castrated and re-implanted
group 3: castrated and transplanted

Question 155

Berthold’s experiment: group 1

Answer 155

castrated

caponization
- small comb and wattles
- no interest in hens
- no aggression towards other males

Question 156

Berthold’s experiment: group 2

Answer 156

castrated and reimplantation of testes

normal male development
- normal comb and wattles
- normal male behaviour

Question 157

Berthold’s experiment: group 3

Answer 157

castration and transplantation of testes

normal male development
- normal comb and wattles
- normal male behaviour

Question 158

Berthold’s 3 major conclusions

Answer 158

1. testes are transplantable organs
2. transplanted testes can function and produce sperm
3. because testes functioned normally after all nerves were severed, there are no specific nerves directing testicular function
   - so certain glands receive info from innervations, but not all
   - can conclude that something in the blood is functioning to affect behaviour

Question 159

most research in behavioural endocrinology involves only a few types of _______ _______. why?

Answer 159

simple behaviour

this narrow focus on only a few behavioural measures is partially a response to the enormous variation in complex behaviours

this approach has advantages and disadvantages

Question 160

categorize behaviour into two main classes

Answer 160

1. description of action
   - how questions: allow us to infer causation and role of experience
2. description of consequence
   - why questions: evolution and function

Question 161

4 things that flow out of “description of action” and “description of consequence”

Answer 161

mechanisms (how question)

development (how question)

evolution (why question)

function (why question)

Question 162

2 areas of “how questions”

Answer 162

1. immediate causation: the physiological mechanisms underlying behaviour
2. development: the role of experience in individual behaviour

Question 163

2 areas of “why questions”

Answer 163

1. evolution: the perspective(s) adopted by biologists who assume that evolutionary processes are central to issues in ecology, systematics, and behaviour
2. adaptive function: the role of any structural, physiological, or behavioural process that increases an individual’s fitness to survive and reproduce

Question 164

3 pieces of evidence needed to determine that a particular hormone affected a specific behaviour OR that a specific behaviour changed hormone concentration

Answer 164

1. a hormonally-dependent behaviour should disappear when the source of the hormone is removed, or the actions of the hormone are blocked
2. after the behaviour stops, restoration of the missing hormonal source or its hormone should reinstate the absent behaviour
3. hormone concentrations and the behaviours in question should be covariant: the behaviour should be observed only when hormone concentrations are relatively high and never/rarely when hormone concentrations are low

Question 165

latency of action of hormones

Answer 165

have a long latency of action

Question 166

manner in which many hormones are released (and an example)

Answer 166

pusatile manner

ie. secretion of cortisol occurs approximately every 90 minutes

Question 167

5 classes of evidence for determining hormone-behaviour interactions

Answer 167

1. quasi-experimental designs
2. comparison groups
3. natural observations
4. non-random assignment
5. use of statistical controls

Question 168

quasi-experimental designs

Answer 168

inferring causation in a research setting in cases where experimenting would be unethical/difficult

this approach falls between experimental and non-experimental designs

aims to investigate cause-and-effect like experimental design, but often lacks some key elements (like random assignment)

Question 169

comparison groups

Answer 169

researchers might compare groups that naturally differ in hormone levels (such as individuals with naturally high vs low testosterone) or groups influenced by external factors (such as individuals using hormone replacemeent therapy versus those not using it)

Question 170

natural observations

Answer 170

these designs often rely on naturally occurring variations in hormone levels rather than manipulating them artificially

try not to influence/bias the quantification

Question 171

non-random assignment

Answer 171

participants aren’t randomly assigned to groups due to limitations in controlling or manipulating hormone levels in a controlled manner

instead, researchers observe and compare existing groups

try to account for confounders in the analysis - lack of random assignment makes it harder to establish causality

Question 172

use of statistical controls

Answer 172

quasi-experimental designs employ statistical techniques to control for confounding variables to strengthen the validity of the findings

Question 173

lack of random assignment makes it harder to establish…

Answer 173

a clear cause-and-effect relationship between hormones and behaviour

Question 174

correlational designs

Answer 174

examination of relationships between variables without intervening or manipulating them

instead of seeking causation, they aim to IDENTIFY ASSOCIATIONS/CORRELATIONS between variables to understand how they relate to each other

Question 175

4 traits of correlational designs

Answer 175

1. measurement of variables
2. assessment of relationships
3. no manipulation of variables
4. identification of associations

Question 176

correlational designs: measurement of variables

Answer 176

researchers measure 2+ variables to determine if they’re related

these variables can be anything measurable (height, age, test scores, hormone levels…)

Question 177

correlational designs: assessment of relationships

Answer 177

statistical analyses, likely correlation coefficients, are used to assess the STRENGTH and DIRECTION of relationships between variables

correlation coefficients range from -1 to 1 (positive, negative or no relationship)

Question 178

correlational designs: no manipulation of variables

Answer 178

in contrast to experimental designs, correlational studies don’t manipulate variables or control experimental conditions

instead, they observe and analyze existing data

Question 179

correlational designs: identifying associations

Answer 179

these studies can reveal is changes in one variable = associated with changes in another variable

ie. correlational study might examine whether there’s a relationship between testosterone levels and aggression

Question 180

longitudinal designs

Answer 180

study changes in variables over an EXTENDED PERIOD within the SAME INDIVIDUALS/GROUPS

unlike cross-sectional studies that capture data at a single point in time, longitudinal studies follow participants over time

Question 181

6 key aspects of longitudinal designs

Answer 181

1. data collection over time
2. tracking changes
3. identification of trends and patterns
4. analysis of stability and change
5. challenges and attrition
6. resource-intensive

Question 182

example of longitudinal study: cortisol in pregnant women

Answer 182

measured cortisol during 1st, 2nd and 3rd trimesters

cortisol release in 1st semester = more similar to non-pregnant women

but in 2nd and 3rd trimester, cortisol is produced more during the day

this expression has an association with depressive symptoms

Question 183

immunoassays

Answer 183

very important technique in behavioural endocrinology

analytical techniques used for the quantification of an analyte (hormone) based on the antigen-antibody reaction

Question 184

antigen

Answer 184

a molecule that can bind to a specific antibody

Question 185

antibodies for a given hormone are produced how?

Answer 185

by injecting the hormone of interest (antigen) into an animal to raise an antibody against the hormone

body produces very specific antibodies, and the given antigen will only bind to a certain antibody

Question 186

bioassay

Answer 186

assays that use LIVING TISSUES/ANIMALS to test effects of hormones/other chemical compounds

useful historically - measured biological response to hormone in question

sometimes determined PRESENCE/ABSENCE of hormone in question

sometimes allowed QUANTITATIVE MEASUREMENT of specific hormones

test the effects of the hormone and measure its biological activity on a living animal

but require much time and labour

Question 187

bioassay example: pregnant rabbits

Answer 187

relies on human chorionic gonadotropin (hCG)

^a hormone produced during pregnancy

1. take pregnant woman’s urine
2. inject that urine into the mice
3. if the hCG hormone was present in the mice, the animal’s ovaries would enlarge and show follicular maturation

Question 188

level of precision in the bioassay rabbit example

Answer 188

98%

Question 189

bioassays: evolution of pregnancy testing

Answer 189

1927-1960: used the animal testing method (urine injection)
- carried out in lab

1960-1988: antibody testing method (blood tests, pregnancy test sticks)
- carried out at the doctor’s office/at home

Question 190

radioimmunoassay (RIA) is based on the principle of…

Answer 190

competitive binding of an antibody to its antigen (hormone) that results in a change in radioactivity

a radioactive antigen competes with a non-radioactive antigen for a fixed number of antibody binding sites

an antibody produced in response to any antigen (in this case a hormone) has a binding site that is specific for that antigen

antibodies have a given number of binding sites for its antigen
- antigen molecules can be “labeled” with radioactivity
- antibody cannot discriminate between radiolabeled (hot) and normal (cold) antigen

radiolabeled hormone and cold hormone compete for binding sites on antibody

so the more cold hormone there is present in the tube, the less hot hormone will bind to the antibody

quantity of hot hormone that binds can be determined by precipitating the antibody and measuring the associated radioactivity resulting from the radiolabeled hormone that remains bound

concentration of hormone in sample can then be determined by subjecting sample to same procedure and comparing results with standard curve

Question 191

competitive binding process in radioimmunoassay

Answer 191

several test tubes with different known concentrations of the hormone (antigens that are unlabeled and radioactive labeled) and the antibody are used to BENCHMARK hormone concentration

Question 192

cold antigen

Answer 192

in radioimmunoassay, the known hormone concentration

Question 193

hot antigen

Answer 193

in radioimmunoassay, the known RADIOLABELED hormone concentration

Question 194

what do radioimmunoassays do?

Answer 194

use antibodies to detect and quantitate the amount of antigen (hormone) in a sample

increase precision with which hormone concentrations can be measured

Question 195

RIA process

Answer 195

in the well, place antibodies

introduce the corresponding antigen
- labelled antigen
- this will bind to the antibodies

then add the unlabelled antigen (ie. from patient serum)

we want to see if the serum has the unlabelled antigen or not

if the sample has a bunch of unlabeled antigens (radioactive), then radioactivity would DECREASE progressively with the increase in antigen concentration

Question 196

if the sample has a bunch of unlabeled antigens, then radioactivity…

Answer 196

radioactivity would decrease progressively with the increase of the antigen concentration

Question 197

if there’s a low level of concentration in the sample, radioactivity…

Answer 197

won’t fall that much

because there’s less competition for binding (less labeled antigens are being replaced by unlabeled antigens)

Question 198

3 main steps of radioimmunoassay

Answer 198

step 1: immune reaction
- radiolabeled antigen
- competition between labeled and unlabeled antigens

step 2: competitive displacement
- radiolabeled antigen released
- unlabeled antigen (hormone) binds

step 3: radioactivity count
- measure radioactivity

Question 199

enzyme immunoassay (EIA) or enzyme linked immunosorbent assay (ELISA)

Answer 199

most common way to quantify hormones

uses an enzyme instead of radioactivity

ie. Rapid Covid Test

Question 200

4 main steps in EIA/ELISA

Answer 200

step 1: have a well of captured antibody
- add the antigen that we want to measure (antigen binds to antibody)

step 2: add labelled antibody
- labelled antibody will attached to first set of antibody/antigen

step 3: add the substrate and enzyme
- substrate will attach to the labelled antibody
- enzyme will cause a change in the substrate that will produce a SIGNAL (ie. change in colour)

detect the signal and/or quantify the product

Question 201

EIA/ELISA can do what two things…

Answer 201

1. detect a hormone (ie. through colour change)
2. quantify a hormone using a standard curve (gradient of colour)

Question 202

immunocytochemistry (ICC) versus immunohystochemistry (IHC)

Answer 202

immunocytochemistry: applied to CELLS

immunohystochemistry: applied to TISSUES

both use antibodies to determine the LOCATION of a hormone in a specific tissue/cell

antibodies linked to marker molecules, such as those in fluorescent dye, are usually introduced into dissected tissue from an animal, where they bind with the hormone/neurochemical of interest

Question 203

immunofluorescence

Answer 203

use fluorescence to determine the location of a hormone in a specific tissue/cell

Question 204

what does autoradiography do?

Answer 204

determines the location of hormonal action

(location of hormonal uptake and receptor location)

Question 205

autoradiography basic idea

Answer 205

radiolabeled hormones are injected into a tissue/animal to determine hormonal uptake and indicate receptor location

Question 206

4 steps of autoradiography

Answer 206

step 1:
- tissues = sliced into several very thin sections
- adjacent sections = subjected to different treatments

step 2:
- one section of target tissue = stained in usual way to highlight various cellular structures

step 3:
- next section = placed in contact with photographic film
- emission of radiation from radiolabeled hormone develops an image on the film

step 4:
- areas of high radioactivity on the film can then be compared with stained section to see how areas of highest hormone concentration correlate with structures

Question 207

autoradiography basic process

Answer 207

1. determine cellular structures
2. use radiation emission to determine location of radiolabeled hormone
3. overlay the structure with the hormone locations

(dark spots on photo of structures = where radiolabeled hormone has undergone binding)

Question 208

blot test - western blot

Answer 208

quantifyies several proteins at the same time

technique used to fractionate mixtures of proteins, DNAs or RNAs so they can hybridize with markers that travel different distances in an electrophorectic gel based on their size

electrophoresis: application of an electric current through a matrix/gel that results in a gradient of molecules separating out along the current basis of size (smaller molecules move farther than larger molecules during a set time period)

Question 209

steps: blot test - Western blot

Answer 209

step 1: get the sample
- tissue of interest is homogenized and the cells are lysed
- makes it so that all the cells’ contents are loose in the fluid

step 2: homogenate is placed in gel and subjected to electrophoresis
- the small electric current applied to the gel separates the proteins based on their electric charges

step 3: transfer gel to a membrane
- protein bands will have formed

step 4: transfer gel to an incubator with a specific antibody
- antibody is specific to the antigen that is being searched for

step 5: detect bound antibody by chemiluminescence

Question 210

in blot test/Western blot, how do we detect the bound antibody?

Answer 210

chemiluminescence

can quantify the substrate that emits the colourful reaction

Question 211

in situ hybridization

Answer 211

determining whether a particular substance is produced in a specific tissue

figuring out WHERE the protein/hormone is produced

Question 212

in situ hybridization follows the principles of…

Answer 212

immunohystochemistry

technique is used to identify cells/tissues in which messenger RNA (mRNA) molecules encoding a specific protein (hormone/neurotransmitter) are being produced

Question 213

why does in situ hybridization look for mRNA?

Answer 213

it looks for specific sequences of mRNA - because if that mRNA is present in a tissue it means that gene transcription is happening for the protein of interest

because mRNA is what carries the genetic info needed to produce proteins

Question 214

4 steps of in situ hybridization

Answer 214

step 1: tissue is fixed, sliced very thin, mounted on slides, and either dipped into an emulsion or placed over film
- developed with photographic chemicals

step 2: tissue is also counterstained to identify specific cellular structures

step 3: radiolabeled cDNA probe is introduced into the tissue. if the mRNA of interest is present in the tissue, the cDNA will form a tight association (hybridize) with it

step 4: the tightly bound cDNA, and hence the mRNA, will appear as dark spots

Question 215

in situ hybridization: the hybridization part

Answer 215

if the mRNA of interest is present in the tissue, the cDNA will form a tight association (hybridize) with it

hybridization will appear as dark spots

Question 216

immunohistochemistry versus in situ hybridization

Answer 216

IHC: marks protein

ISH: marks RNA associated with gene expression for the same protein

Question 217

PCR stands for

Answer 217

polymerase chain reaction

Question 218

applying immunoassays and genetic marking for COVID - PCRs

Answer 218

PCRs use fluorescence

PCRs amplify and replicate a specific segment of DNA and RNA

this process creates NUMEROUS copies of the targeted DNA/RNA

this enables detection and analysis

basically, saliva provides nucleic acids and RNA or DNA - any viral contents will be marked and become fluorescent

the viral mRNA will bind to complementary DNA of the test

then we’ll create a reaction to amplify the signal and we can quantify the presence of the hormone

Question 219

applying immunoassays and genetic marking for COVID - lateral flow immunoassay technology

Answer 219

in a RAPID ANTIGEN TEST

patient test sample is mixed with chemicals that react with specific proteins on the surface of the SARS-Cov-2 virus

saliva swabs - if mRNA from virus is present, the immune response will occur and colour will change

Question 220

7 types of immunoassays

Answer 220

1. bioassays
2. radioimmunoassays
3. enzyme immunoassays (EIA) or enzyme linked immunosorbent assay (ELISA)
4. autoradiography
5. blot tests
6. in situ hybridization

Question 221

bioassay in a nutshell

Answer 221

biological assays assessing the effects of substances

uses living animal tissues

Question 222

radioummunoassay in a nutshell

Answer 222

measures concentrations of antigens using radioactive labels

concentrations of a given hormone is inversely related to the radioactive labels

measures concentrations using standard curves

Question 223

enzyme immunoassay (EIA) or enzyme linked immunosorbent assay (ELISA)

Answer 223

detects antigens or antibodies using enzyme-based reactions

Question 224

immunocytochemistry (ICC)/immunohystochemistry

Answer 224

visualizes proteins in cells (ICC) or tissues (IHC)

does this using immmunohystochemistry

labels antibodies with dyes or enzymes

Question 225

autoradiography in a nutshell

Answer 225

captures and visualizes radioactively labeled molecules in the tissue

photographic film is overlayed with an adjacent stained tissue

Question 226

blot wests in a nutshell

Answer 226

techniques (ie. Western blot) for transferring and detecting biomolecules using specific probes

detects several proteins at same time

Question 227

in situ hybridization in a nutshell

Answer 227

locates and visualizes specific nucleic acid sequences (ie. mRNA) within cells or tissues

Question 228

pharmacological techniques

Answer 228

use of synthetic chemical agents can alter the action/function of a hormone

two major groups of synthetic chemical agents

Question 229

2 major groups of synthetic chemical agents

Answer 229

1. agonists: simulate endocrine function by affecting hormonal release
2. antagonists: inhibit endocrine function by affecting hormonal release (blocking hormones)

Question 230

example of pharmacological technique

Answer 230

cyproterone acetate -> anti testosterone

cyproterone acetate binds to the testosterone reception

inactivates it

testosterone levels fall

Question 231

brain imaging 2 techniques

Answer 231

1. Positron Emission Tomography (PET)
2. Functional Magnetic Resonance Imaging (fMRI)

Question 232

positron emission tomography

Answer 232

PET

injection of radiotracers - specific molecules (hormone)

PET scanner detects the radioactivity as the compound accumulates in different regions

can infer the locus of the hormone’s action

Question 233

functional magnetic resonance imaging

Answer 233

fMRI

involves exposing brain to multiple magnetic fields

high spatial and temporal resolution

detects changes in brain activity during specific tasks/conditions

can be task-based or resting-state

Question 234

gene

Answer 234

discrete region of DNA within a chromosome that when expressed (transcribed), leads to the production of ribonucleic acid (RNA)

Question 235

transgenic

Answer 235

relating to an animal in which a gene has been INSERTED, ALTERED, or DELETED

Question 236

knockout

Answer 236

an individual, usually a mouse, in which a specific gene has been INACTIVATED

Question 237

chimera

Answer 237

animal whose tissues are composed of two or more genetically distinct cell types

alter DNA in the embryonic (not yet differentiated) cells
- these cells will multiply in the embryo
- born as chimera

Question 238

alternative name for a chimera

Answer 238

mosaic

Question 239

new inducible knockouts

Answer 239

new innovation

timing and tissue-specific placement of the targeted gene disruption can be controlled

Question 240

genetic manipulations

Answer 240

insertion, alteration (over or under-expression), deletion of genes

study resulting behaviour

Question 241

CRISPR/Cas 9

Answer 241

CRISPR (clustered regularly interspaced short palindromic repeats)

revolutionary tech in molecular biology that allows precise editing of genes WITHIN organisms

involves cutting DNA at specific location using the Cas9 protein guided by a designed RNA sequence

this precise DNA cleavage allows researchers to introduce modifications by relying on the cell’s natural repair mechanisms

allows insertion of new DNA sequence

Question 242

integrating diff hormone & behaviour methods: hunger hormones - Leptin

Answer 242

leptin is a hormone that helps maintenance of normal weight on a long term basis

Question 242

level of leptin in blood is directly related to…

Answer 242

the amount of body fat that you have

Question 243

leptin resistance causes you to…

Answer 243

feel hungry and eat more even though your body has sufficient fat stores

Question 244

ob mice

Answer 244

specific mutations in mice cause extreme obesity in those that are homozygous for the defective gene

considered natural knockouts

Question 245

from the ob mice, a mice strain was devised for…

Answer 245

studies of body mass regulation

Question 246

ob/ob mice have a pair of…

Answer 246

defective ob genes

they are HYPERPHAGIC (overeat), obese, reproductively sterile

Question 247

researchers take advantage of purified leptin…

Answer 247

availability of purified leptin allows researchers to produce specific antibodies to this substance that could be used in developing assays to determine concentration in blood

Question 248

an RIA was developed to…

Answer 248

determine the blood plasma leptin concentrations of obese and diabetic humans

the anti-leptin antiserum was raised in a rabbit against highly purified recombinant human leptin

Question 249

immunocytochemical localization techniques revealed that leptin was present in…

Answer 249

both white and brown adipose tissue as well as other peripheral tissues

Question 250

to determine the site of action of leptin in the brain…

Answer 250

purified leptin was labeled with a radioactive tag and then injected into mice

autoradiography

Question 251

differences in what blot tests versus in situ hybridization can determine

Answer 251

blot tests can typically determine WHETHER OR NOT a particular substance is PRESENT in a specific tissue

in situ hybridization can determine WHETHER a particular substance is PRODUCED in a specific tissue
- can also quantify the substance being produce
- and have higher resolution/sensitivity than blot tests

Question 252

hormones

Answer 252

chemical messengers that travel through the blood stream

target specific organs/tissues

Question 253

hormones coordinate…

Answer 253

the physiology and behaviour of an animal

they do this by regulating, integrating and controlling its bodily function

Question 254

can hormones have more than one effect?

Answer 254

yes

examples: gonadotropin hormone, epinephrine

Question 255

can hormonal messages travel anywhere in the body?

Answer 255

yes

they can travel anywhere in the body via the circulatory system

any cell receiving blood is potentially able to receive a hormonal message

hormonal messages can travel up to 2 meters in the blood system

Question 256

main 2 differences between hormonal and neural signalling

Answer 256

1. speed
   - because hormones travel through the blood, hormonal signals are slower than neural ones
2. precision
   - as hormones travel long distances, they need very specific receptors
   - the specificity of receptors is what makes hormonal signalling so precise

Question 257

double action of the epinephrine hormone

Answer 257

epinephrine can have more than one effect

1. in liver cell
   - epinephrine binds to beta receptor
   - causes glycogen deposits to break down
   - glucose is released from cell
2. in skeletal muscle blood vessel
   - epinephrine attaches to beta receptor
   - vessel dilates

Question 258

5 forms of chemical communication

Answer 258

1. intracrine mediation
2. autocrine mediation
3. paracrine mediation
4. endocrine mediation
5. ectocrine mediation

Question 259

intracrine mediation

Answer 259

intracrine substances regulate INTRACELLULAR events

ie. molecules produced at the nucleus of a neuron affect the axon of the same cell

Question 260

autocrine mediation

Answer 260

autocrine substances feed back to influence the same cells that secreted them

LEAVE AND THEN RETURN TO THE SAME CELL

affect the cell that first produced the hormone

cells have receptors for their own products

Question 261

paracrine mediation

Answer 261

paracrine cells secrete chemicals that affect ADJACENT CELLS

Question 262

endocrine mediation

Answer 262

endocrine cells secrete chemicals into the BLOODSTREAM, where they may travel to DISTANT TARGET CELLS

Question 263

ectocrine mediation

Answer 263

released into the ENVIRONMENT by individuals to communicate with others

ie. pheromones

Question 264

chemical messenger

Answer 264

any substance that is produced by a cell that affects the function of another cell

Question 265

cytokine

Answer 265

chemical messenger that evokes proliferation of other cells

especially in the immune system

Question 266

hormone

Answer 266

chemical messenger that’s released into the bloodstream or tissue fluid system that affects the function of target cells some distance from the source

Question 267

neurohormone

Answer 267

hormone produced by a neuron

Question 268

neuromodulator

Answer 268

hormone that changes (modulates) the response of a neuron to some other factors

Question 269

neuropeptide

Answer 269

peptide hormone produced by a neuron

Question 270

neurosteroid

Answer 270

steroid hormone produced by a neuron

Question 271

neurotransmitter

Answer 271

chemical messenger that acts across the neural space

Question 272

can neurotransmitters be neurohormones?

Answer 272

yes

produced in hypothalamus or pituitary

pass along the axons of neurons and then are released into the bloodstream

Question 273

examples of neurohormones

Answer 273

oxytocin

vasopressin

norepinephrine

gonadotropin-releasing hormone

corticotropin-releasing hormone

Question 274

T/F: endocrine glands are ductless

Answer 274

true

closed structure - no ducts that communicate with body

so rely on blood vessels for communication

Question 275

T/F: endocrine glands have a rich blood supply

Answer 275

true

Question 276

5 main features of the endocrine system

Answer 276

1. endocrine glands are ductless
2. endocrine glands have a rich blood supply
3. hormones, the products of endocrine glands, are secreted into the bloodstream
4. hormones can travel in the blood to virtually every cell in the body and can thus potentially interact with any cell that has appropriate receptors
5. hormone receptors are specific binding sites, embedded in the cell membrane or located elsewhere in the cell, that interact with a particular hormone/class of hormones

Question 277

where are hormone binding sites/receptors located?

Answer 277

either embedded in the cell membrane

or located elsewhere in the cell

Question 278

can glands be both endocrine and exocrine?

Answer 278

yes

like the pancreas

Question 279

endocrine versus exocrine

Answer 279

exocrine:
- secrete substances into a ductal system to an epithelial surface

endocrine:
- secrete products directly into the bloodstream

Question 280

pancreas: endocrine and exocrine components

Answer 280

exocrine: pancreas secretes digestive juices into the intestines via DUCTS

endocrine: pancreas secretes hormones directly into the BLOODSTREAM

from here they travel throughout the body to regulate energy utilization and storage

Question 281

receptor concentration and hormone concentration can interact…

Answer 281

insufficient receptors might cause endocrine deficiency

if there aren’t enough receptors, we call this ‘resistance’
ie. insulin resistance

Question 282

cross-reaction

Answer 282

when the blood concentration of a hormone is high, they can sometimes bind with receptors that are meant for a different hormone

causes a biological response

Question 283

hormone molecules vary substantially in…

Answer 283

1. size
2. chemical properties

Question 284

major chemical classes of hormones

Answer 284

polypeptides (proteins and peptides)

steroids

amines

lipid-based (some authors don’t include this last one)

Question 285

amines can be both…

Answer 285

water-soluble (hydrophilic)

or

lipid-soluble (hydrophobic)

Question 286

other term for water-soluble

Answer 286

hydrophilic

Question 287

other term for lipid-soluble

Answer 287

hydrophobic

Question 288

polypeptides: hydrophilic or hydrophobic?

Answer 288

hydrophilic (water-soluble)

so they dissolve well in watery plasma blood

but the cell membrane = lipid - so water can’t mix

so polypeptides bind to the cell’s surface receptors, which relay info to nucleus via intracellular signalling

Question 289

where are polypeptides stored?

Answer 289

in vesicles within cells

can’t freely enter cell because cell membrane is made of lipids

Question 290

steroids: hydrophilic or hydrophobic?

Answer 290

hydrophobic (lipid-soluble)

can easily pass through the lipid cell membrane

but cannot travel through watery blood

so need a transporter protein to move through blood

Question 291

to travel through blood, what to steroids need?

Answer 291

a transporter protein

because steroids are hydrophobic

Question 292

how are peptide hormones released from parent cell? how about steroid hormones?

Answer 292

peptide hormones = exocytosis

steroid hormones = simple diffusion

Question 293

reminder: study hormone chart

Answer 293

it’s in onenote

Question 294

if a hormone acts inside a nucleus, it likely has…

Answer 294

transcriptional properties

Question 295

any hormone with ‘chorionic’ in its name is…

Answer 295

produced by the placenta

Question 296

8 major endocrine structures

Answer 296

1. hypothalamus
2. pineal gland
3. pituitary gland (anterior and posterior)
4. thyroid
5. adrenal glands (medulla and cortex)
6. pancreas
7. gut
8. gonads (testes/ovaries)

Question 297

hypothalamus: main function it regulates

Answer 297

control of hormone secretions

Question 298

pineal gland: main function it regulates

Answer 298

reproductive maturation

body rhythm

Question 299

anterior pituitary: main function it regulates

Answer 299

hormone secretion by thyroid, adrenal cortex and gonads

growth

Question 300

posterior pituitary: main function it regulates

Answer 300

water balance

salt balance

Question 301

thyroid: main function it regulates

Answer 301

growth and development

metabolic rate

Question 302

adrenal cortex (outer bark): main function it regulates

Answer 302

salt and carbohydrate metabolism

inflammatory reactions

Question 303

adrenal medulla (inner core): main function it regulates

Answer 303

emotional arousal

Question 304

pancreas (islets of Langerhans): main function it regulates

Answer 304

sugar metabolism

Question 305

gut: main function it regulates

Answer 305

digestion and appetite control

Question 306

gonads (testes/ovaries): main function it regulates

Answer 306

body development

maintenance of reproductive organs in adults

Question 307

hypothalamus

Answer 307

comprises several collections of neuronal cell bodies (nuclei)

at the base of the brain

receives projections from the brain

controls hormone secretion (and produces hormones)

Question 308

2 main types of hormones released by the hypothalamus

Answer 308

1. releasing hormones
   - stimulates the release of certain hormones from glands
2. inhibiting hormones
   - inhibits the release of certain hormones from glands

Question 309

hypothalamus: 6 main releasing hormones

Answer 309

1. thyrotropin-releasing hormone (TRH)
2. growth hormone-releasing hormone (GHRH, somatocrinin)
3. gonadotropin-releasing hormone (GnRH)
4. melanotropin-releasing hormone (MRH)
5. corticotropin-releasing hormone (CRH)
6. kisspeptin

^these are all EXCITATORY

Question 310

hypothalamus: 3 main inhibiting hormones

Answer 310

1. somatostatin (growth hormone-inhibiting hormone/GHIH)
2. gonadotropin inhibitory hormone (GnIH)
3. dopamine (DA)

^these are all INHIBITORY

Question 311

where is the hypothalamus and what is it composed of?

Answer 311

it’s at the base of the brain

comprises several collections of neuronal cell bodies or nuclei

receives projections from the brain

Question 312

corticotropin-releasing hormone (CRH)

Answer 312

excitatory hypothalamic hormone

stimulates secretion of ADRENOCORTICOTROPIC hormone

Question 313

releasing hormones do what

Answer 313

act on another gland - get it to release a hormone

Question 314

every time you see ‘tropic’, think about…

Answer 314

nourishment

ie. adrenocorticotropic means a hormone that nourishes the adrenal gland

Question 315

gonadotropin-releasing hormone (GnRH)

Answer 315

excitatory hypothalamic hormone

controls the release of:

1. LUTEINISING HORMONE (LH)
2. FOLLICLE-STIMULATING HORMONE (FSH)

Question 316

growth hormone-releasing hormone (GH-RH)

Answer 316

excitatory hypothalamic hormone

tells appropriate gland to release growth hormone (GH)

Question 317

thyrotropin-releasing hormone (TRH)

Answer 317

excitatory hypothalamic hormone

tells pituitary gland to produce/release THYROID-STIMULATING HORMONE (TSH)

Question 318

melanotropin releasing hormone (MRH)

Answer 318

excitatory hypothalamic hormone

stimulates secretion of melanotropin

Question 319

kisspeptin

Answer 319

excitatory hypothalamic hormone

initiates secretion of gonadotropin-releasing hormone (GnRH) at puberty

thus is involved in sexual maturation

but it role isn’t yet clearly described

Question 319

dopamine (DA)

Answer 319

inhibitory hypothalamic hormone

dopamine is typically excitatory but in the endocrine system it’s inhibitory

prolactin-inhibitory hormone

Question 319

somatostatin (SOM)

Answer 319

inhibitory hypothalamic hormone

acts to inhibit secretion of:
1. growth hormone (GH)
2. thyroid-stimulating hormone (TSH)

also has inhibitory effects on insulin, glucagon, secretin production

Question 320

pituitary gland was once considered what?

Answer 320

the “master gland”

Question 321

why was pituitary once considered the “master gland”?

Answer 321

because it mediates so many physiological processes - it secretes many hormones

but now we know that it receives lots of commands from the hypothalamus

it’s really two distinct glands fused into one

Question 322

the two different embryological origins of the pituitary

Answer 322

1. roof of the mouth = anterior pituitary
2. base of the brain = posterior pituitary

Question 323

how do neurohormones from hypothalamus reach anterior pituitary?

Answer 323

via the PORTAL SYSTEM

Question 324

portal system

Answer 324

the way that neurohormones travel from the hypothalamus to the anterior pituitary

special closed blood circuit

two beds of capillaries (one in hypothalamus and one in anterior pituitary) are connected by a vein

hypothalamic factors stimulate cells in the anterior pituitary to secrete hormones in general circulation

Question 325

how do neurohormones from hypothalamus reach posterior pituitary?

Answer 325

hypothalamic neuro-secretory cells

these cells innervate DIRECTLY to the posterior pituitary

rather than being released into portal system, neurohormones are secreted directly into this structure

here they enter blood vessels and the general circulation

Question 326

anterior pituitary: 3 steps of hormone release

Answer 326

1. axon terminals of hypothalamic neurons release neurohormones near capillaries that give rise to portal vessels
2. neurohormones from portal vessels stimulate or inhibit the release of hormones from anterior pituitary cells
3. anterior pituitary hormones leave the gland via the blood

so two steps really: hypothalamus releases neurohormones into the portal and then in response, the pituitary releases the specific hormones into general circulation

Question 327

3 main anterior pituitary hormones

Answer 327

1. corticotropin-related peptides (painkillers/stress response)
   - adrenocorticotropic hormone (ACTH)
   - melanocyte-stimulating hormone
   - beta-endorphins
2. somatomammotropins (growth, breast milk)
   - growth hormone (GH or somatotropin)
   - prolactic (PRL)
3. glycoproteins (thyroid, gonads, sex hormones)
   - thryoid-stimulating hormone (TSH)
   - luteinizing hormone (LH)
   - follicle-stimulating hormone (FSH)

Question 328

what do corticotropin-related peptides do?

Answer 328

(anterior pituitary hormones)

1. ACTH:
   stimulate synthesis/release of the following from the adrenal glands:
   - glucocorticoids
   - mineralocorticoids
   - androgenic steroids

• exposure to stressful events can trigger ACTH release

2. beta-endorphins:
   endogenous opioids that resemble opiates in its action as a “natural” pain killer

Question 329

anterior pituitary hormones are often considered as what? and why?

Answer 329

polypeptides tropic hormones

because they stimulate various physiological processes

either by acting directly on target tissues or by causing other endocrine glands to release hormones

Question 330

what do somatomammotropins do?

Answer 330

(anterior pituitary hormones)

(think ‘soma’ - ‘body’ - growth)

1. growth hormone (GH):
   promote linear growth

a) GH and somatotropin:
enhance amino acid uptake and mRNA transcription/translation
- increased protein synthesis

2. prolactin:
   promotes breast development, initiates milk synthesis

Question 331

what do glycoproteins do?

Answer 331

(anterior pituitary hormones)

1. TSH:
   works on thyroid gland to stimulate uptake of iodide and release of thyroid hormones
2. LH and FSH:
   bind to receptors in ovaries and testes, regulate gonad function
   stimulate sex steroid production and development of gametes

Question 332

posterior pituitary: 3 steps of hormone release

Answer 332

1. hypothalamic neurons produce vasopressin and oxytocin and transport them to the posterior pituitary
2. the neurohormones are released in the posterior pituitary and diffuse into capillaries
3. then leave the posterior pituitary via the blood

hormones from posterior pituitary enter circulation more quickly than those from anterior pituitary

Question 333

oxytocin and vasopressin in relation to the posterior pituitary

Answer 333

1. oxytocin and vasopressin = made and packaged in neurosecretory cell bodies
2. then are transported down the axons to be stored in vesicles at the axon terminals in the posterior pituitary
3. can be released in response to a NEURAL IMPULSE via exocytosis and enter the bloodstream

SO POSTERIOR PITUITARY HORMONES CAN BE RELEASED AS FAST AS NEURAL IMPULSES

Question 334

how are vasopressin and oxytocin released?

Answer 334

FROM VESICLES, SUPER QUICKLY

released from vesicles at axon terminals

in response to neural impulse via exocytosis

from here enter bloodstream

release is as fast as neural impulses

Question 335

hormones associated with the posterior pituitary

Answer 335

vasopressin

oxytocin

Question 336

vasopressin

Answer 336

aka antidiuretic hormone (ADH)

acts to retain water in the body

Question 337

what does vasopressin do during serious blood loss?

Answer 337

it has pressor (hypertensive) effects

pressor - pressin

it causes the CONSTRICTION of blood vessels to help deal with blood loss

Question 338

oxytocin (5 points)

Answer 338

1. influences reproductive function in mammals
2. important during birth
3. causes uterine contractions
4. often used to medically induce labour
5. involved in suckling reflex

Question 339

reminder to look at screenshot of hypothalamic hormones and what hormones they stimulate/inhibit

Answer 339

it’s on desktop

Question 340

pineal gland location

Answer 340

top of midbrain

above third ventricle

just in front of cerebellum

Question 341

pineal gland secretes what?

Answer 341

melatonin

Question 342

what pineal cells produce melatonin?

Answer 342

secretary cells called PINEALOCYTES

produce melatonin, that resembles serotonin

Question 343

pinealocytes

Answer 343

cells in the pineal gland

they produce melatonin

Question 344

how is melatonin synthesized?

Answer 344

synthesized from melatonin via the amino acid tryptophan

Question 345

how is melatonin secreted?

Answer 345

secreted into cerebrospinal fluid and bloodstream

Question 346

what is melatonin secretion regulated by?

Answer 346

the sympathetic NS in response to changing light levels

as light levels fall, melatonin secretion increases

as light levels rise, melatonin secretion ceases

Question 347

pineal gland’s main function

Answer 347

related to control of the CIRCADIAN CYCLE OF SLEEP AND WAKEFULNESS by secreting melatonin

Question 348

thyroid

Answer 348

large bilateral structure

in the neck

consists of many spherical follicles

Question 349

what do the thyroid’s spherical follicles produce?

Answer 349

thyroid hormones

in direct response to the thyrotropin-releasing hormone released by the anterior pituitary

Question 350

what does the thyroid gland produce?

Answer 350

iodinated substances

T3 and T4

produces these dependent upon dietary levels of iodate

low levels of dietary iodine result in REDUCED THYROID FUNCTION and HYPERTROPHY

Question 351

how does reduced thyroid function and hypertrophy manifest physiologically?

Answer 351

swelling in the neck

Question 352

thyroid hormones do what?

Answer 352

increase oxidation rates in tissue

3 general areas of effect in mammals:
1. metabolism
2. growth and differentiation
3. reproduction

Question 353

2 thyroid hormones

Answer 353

triiodothyronine (T3)

thyroxine (T4)

Question 354

both T3 and T4 are fat-soluble, and they diffuse…

Answer 354

rapidly across cell membranes

but they need carrier protein to travel through the blood

Question 355

4 key functions of T3 and T4

Answer 355

1. regulation of body metabolism
2. control of development of brain and nervous system
3. sexual maturation
4. temperature regulation

Question 356

2 forms of thyroid dysfunction

Answer 356

1. hyperthyroidism
   - too much T3 and T4 are produced
   - weight loss, fast heart rate, weak menstrual cycle, shaky hands
2. hypothyroidism
   - under-active thyroid
   - weight gain, constipation, cold sensitivity

Question 357

Ronaldo was diagnosed with what?

Answer 357

hypothyroidism

had problems with weight

Question 358

parathyroid glands are located where?

Answer 358

at the rear of the thyroid

Question 359

hormones produced by the parathyroid gland and by C cells of the thyroid are both…

Answer 359

1. both are protein hormones
2. both are involved in calcium metabolism

Question 360

parathyroid (PTH)

Answer 360

produced by C cells

elevates blood levels of calcium

does this by increasing reabsorption of calcium from the bone and from the gut

via its effects on vitamin D3

also inhibits phosphate reabsorption from the kidney, reducing calcium clearance

Question 361

calcitonin (CT)

Answer 361

released from C cells of the thyroid

acts in opposition to parathyroid hormone

lowers blood levels of calcium by inhibiting the release of calcium from bone

Question 362

PTH and CT are both controlled directly by…

Answer 362

blood calcium levels

there are no pituitary tropic hormones (releasing hormones) involved in their regulation

direct reaction to calcium levels in blood

Question 363

pancreas functions as both…

Answer 363

an endocrine and exocrine gland

Question 364

most of the pancreas consists of…but…

Answer 364

exocrine cells

these produce and secrete DIGESTIVE JUICES into the intestines

BUT nested throughout the exocrine tissue are islands of endocrine tissue called islets of Langerhans

Question 365

exocrine cells of pancreas do what?

Answer 365

produce and secrete digestive juices into the intestines

Question 366

what are the endocrine cells of the pancreas called?

Answer 366

islets of Langerhans

Question 367

islets of Langerhans

Answer 367

islands of endocrine tissue nested throughout the exocrine tissue of the pancreas

within these endocrine islands, there are 4 cell types:
- alpha cells
- beta cells
- theta cells
- polypeptide-secreting cells

Question 368

glucagon

Answer 368

simple peptide

similar to those of secretin family

typically has 29 amino acids

released from alpha cells of the pancreas

Question 369

do all cells have insulin receptors?

Answer 369

yes, all cells do

NS (neuronal) cells do as well

so insulin can have effects in the CNS as well as the PNS

insulin resistance is correlated with depression and bipolar

Question 370

where does glucagon go once released from alpha cells?

Answer 370

once released from the alpha cells of the pancreas, glucagon travels first to the liver

in the liver it stimulates glycogenolysis

Question 371

glycogenolysis

Answer 371

breakdown of stored glycogen

this acts in opposition of insulin and serves to increase blood levels of glucose

Question 372

alpha cells do what? for what purpose?

Answer 372

alpha cells release gulcagon

glucagon travels to the liver

there it stimulates glycogenolysis (breakdown of stored glycogen)

acts in opposition of insulin: SERVES TO INCREASE BLOOD LEVELS OF GLUCOSE

Question 373

ultimately, alpha cells do what?

Answer 373

release glucagon to increase blood levels of glucose

Question 374

beta cells produce what?

Answer 374

insulin

Question 375

what does insulin promote?

Answer 375

efficient movement of energy from the blood into the cells

can lower blood sugar

Question 376

diabetes

Answer 376

disease caused by:

1. insulin deficiency
2. decreased response to insulin in target tissues

thought that in type I diabetes, pancreatic islets are destroyed by immune assaults (autoimmune disorder)

Question 377

insulin is the only known hormone that can…

Answer 377

lower blood sugar

Question 378

glucagon versus insulin

Answer 378

1. glucagon releases glucose into blood stream
2. insulin lowers blood sugar

they work in opposition with one another

Question 379

theta cells

Answer 379

release somatostatin

somatostatin inhibits insulin release and glucagons locally in the pancreas

Question 380

somatostatin

Answer 380

inhibitory hormone released from theta cells

inhibits insulin and glucagon release in pancreas

somatostatin = also released from hypothalamus to regulate release of growth hormone from anterior pituitary

Question 381

type I versus type II diabetes

Answer 381

type I:
- genetic condition appearing in early life
- auto-immune condition: immune system attacks and destroys insulin-producing beta cells in the pancreas

type II:
- lifestyle related disease
- develops over time
- either your body isn’t able to produce sufficient insulin because you’re consuming too much sugar OR the insulin you create isn’t working properly

type III?
- alteration of insulin metabolism in brain
- common in Alzheimer’s

Question 382

two possibilities in type II diabetes

Answer 382

1. body can’t produce enough insulin because you’re consuming too much sugar
2. the insulin being produced by your body isn’t working properly

Question 383

adrenal gland location

Answer 383

atop the kidneys

Question 384

2 distinct regions of the adrenal gland

Answer 384

1. adrenal cortex
2. adrenal medulla

Question 385

adrenal cortex

Answer 385

has distinct cellular zones with diff functional roles

1. zona glomerulosa (outside)
2. zona fasciculata (middle)
3. zona reticularis (inside)

Question 386

zona glomerulosa

Answer 386

marked by WHORLS of epithelial cells

aldosterone

Question 387

zona fasciculata

Answer 387

epithelial cells are organized in ORDERLY BANDS

glucocorticoid

Question 388

zona reticularis

Answer 388

epithelial cells are DISORGANIZED

sex steroid hormones

Question 389

adrenal medulla

Answer 389

made up of CHROMAFFIN CELLS

in embryonic development: these cells = derived from primitive neural tissue

after birth they work as part of the ANS

respond to neural signals

Question 390

chromaffin cells

Answer 390

make up the adrenal medulla

derived from embryonic primitive neural tissue

post-birth: work as part of ANS

respond to neural signals that come from the spinal cord

Question 391

in response to neural signals, adrenal medulla releases…

Answer 391

3 monoamine hormones

Question 392

3 monoamine hormones released by the adrenal medulla

Answer 392

1. epinephrine
2. norepinephrine
3. dopamine

Question 393

class of protein hormones released from adrenal medulla (in addition to the monoamine hormones)

Answer 393

enkephalins

Question 394

why/how is the adrenal medulla important for fight or flight?

Answer 394

epinephrine and norepinephrine

and because chromaffin tissue: receives neural signals so quite fast

Question 395

HPA axis

Answer 395

hypothalamic pituitary adrenal axis

Question 396

tissue in medulla of adrenal glands receives info through what?

Answer 396

through innervations to spinal cord

short term effects - fast

Question 397

tissue in adrenal cortex receives info through what?

Answer 397

the blood

longer term effects - more prolonged

Question 398

3 zones of the adrenal cortex release what hormones?

Answer 398

1. aldosterone
2. glucocorticoid
3. sex steroid hormones

Question 399

2 functions of gonads

Answer 399

(these functions are usually compartmentalized)

1. production of GAMETES (sperm or eggs)
2. production of HORMONES

Question 400

hormones produced by gonads are primarily of what type?

Answer 400

steroid hormones

Question 401

what are steroid hormones required for?

Answer 401

gamete development

development of secondary sex characteristics

also mediate behaviours necessary to bring sperm and eggs together

Question 402

what regulates the function of the gonads?

Answer 402

tropic hormones from the anterior pituitary

these are called gonadotropins

Question 403

gonadotropins

Answer 403

tropic hormones from the anterior pituitary

regulate gonad function

Question 404

HPG axis

Answer 404

hypothalamic pituitary gonad axis

Question 405

testes

Answer 405

bilateral glands

located in most mammals in an external sac called the scrotum

seminiferous tubules

Question 406

seminiferous tubules

Answer 406

long, convoluted tubes

where sperm cells undergo various stages of maturation (spermatogenesis)

Question 407

sertoli cells

Answer 407

located along basement membrane of seminiferous tubules

involved in spermatogenesis

facilitate progression of germ cells to spermatozoa

via direct contact and by controlling environmental milieu within seminiferous tubules

Question 408

leydig cells

Answer 408

interstitial cells between seminiferous tubules in the testes

produce androgens/testosterone

Question 409

leydig cells produce testosterone in response to what?

Answer 409

in response to the luteinizing hormone from the anterior pituitary

Question 410

sertoli versus leydig cells

Answer 410

both work in testes

sertoli: aid spermatogenesis

leydig: produce androgens in response to LH

Question 411

ovaries: 4 main features

Answer 411

1. paired glands located in dorsal part of abdominal cavity, normally below kidneys
2. compartmentalized (diff parts have diff functions)
3. within fetal ovary are germinal epithelia - eventually develop into primordial follicles
   - infant ovaries contain about 500 000 immature follicles
   - approx 400 eggs (ova) are ovulated by women between puberty and menopause
4. three functional units:
   - follicles
   - corpora lutea
   - stroma

Question 412

where are the ovaries located?

Answer 412

dorsal part of the abdominal cavity

normally below the kidneys

Question 413

ovaries: germinal epithelia eventually develop into…

Answer 413

primordial follicles

Question 414

how many immature follicles are contained in infant ovaries?

Answer 414

about 500 000

Question 415

how many eggs are ovulated by average woman between puberty and menopause?

Answer 415

400 eggs

Question 416

3 main functional subunits of the ovaries

Answer 416

1. follicles
2. corpora lutea
3. stroma

Question 417

atresia

Answer 417

the continual degeneration of follicles throughout life

no additional gametes are formed postnatally

Question 418

stroma

Answer 418

noendocrine connective tissue of endocrine glands

Question 419

follicles

Answer 419

epithelial cell-lined sacs that contain an egg

Question 420

egg/ovum

Answer 420

haploid female gamete

contained in folliclees

Question 421

corpora lutea

Answer 421

endocrine structures that form from remnants of ovarian follicles after the egg is released

secrete progestins

Question 422

what secretes progestins?

Answer 422

corpora lutea

Question 423

what do progestins do?

Answer 423

support the uterine lining in prep for blastocyst implantation

Question 424

each primary follicle consists of an…

Answer 424

ovocyte

Question 425

ovocyte

Answer 425

an immature egg

Question 426

what surrounds the ovocyte?

Answer 426

layer of epithelial cells called GRANULOSA cells

Question 427

granulosa cells

Answer 427

epithelial cells that surround the ovocyte

Question 428

what do granulosa cells produce? what do these cells regulate?

Answer 428

two peptide hormones

1. inhibin
2. activin

these hormones regulate hypothalamus and pituitary gland

Question 429

theca cells

Answer 429

surround granulosa cells

during follicular maturation

these cells participate in estrogen synthesis

Question 430

antrum

Answer 430

space between ovum and surrounding epithelial cells

filled with fluid prior to ovulation

Question 431

as the antrum enlarges, the follicle is called a…

Answer 431

tertiary follicle

Question 432

antrum fluid

Answer 432

called the follicular fluid

is rich in steroid hormones

Question 433

what is in follicle called when it reaches its maximal size?

Answer 433

Graafian follicle

Question 434

what happens to the granulosa cells and theca cells after ovum release?

Answer 434

after ovum release

both granulosa cells of the erupted follicle

and the surrounding thecal cells

UNDERGO RAPID MITOSIS

and CAPILLARIES GENERATED FROM THE THECAL CELLS VASCULARIZE THE GRANULOSA CELLS

Question 435

how does the corpus luteum form?

Answer 435

from the rapid mitosis that occurs in the granulosa and thecal cells following ovum release

and from the vascularization of the granulosa cells by the capillaries generated from the thecal cells

Question 436

how long does the corpus luteum persist for? what do they do?

Answer 436

corpus luteum persists for some time on surface of ovary

produce another class of important sex steroid hormones: progestins

Question 437

progestins

Answer 437

important sex steroid hormones

produced by the corpus luteum after ovum release

Question 438

zona pellucida

Answer 438

multiple layer of epithelial cells that surrounds the follicle

Question 439

placenta: 4 main features

Answer 439

1. temporary endocrine organ that develops in uterus during mammal pregnancy
   - forms from tissues derived from blastocyst and maternal uterus
2. important in maintaining nutritional, respiratory, and excretory functions for fetus
3. source of several steroid and peptide hormones that affect mother and offspring
4. pregnancy tests measure human chorionic gonadotropin (hCG), a hormone produced by rudimentary placenta that forms right after blastocyst implantation

Question 440

what does the placenta form from?

Answer 440

tissues derived from:

1. blastocyst
2. maternal uterus

Question 441

what functions is the placenta important for maintaining within the fetus?

Answer 441

1. nutritional functions
2. respiratory functions
3. excretory functions

Question 442

placenta is the source of several _____ and ______ _____ that affect both the _____ and the _______

Answer 442

steroid and peptide hormones

mother and the offspring

Question 443

what do pregnancy tests measure?

Answer 443

human chorionic gonadotropin (hCG)

^hormone produced by rudimentary placenta that forms immediately after blastocyst implantation

Question 444

blastocyst

Answer 444

cluster of dividing cells made by a fertilized egg

early stage of the embryo

Question 445

what’s relaxin produced by?

Answer 445

not produced by placenta

BUT by the corpora lutea during pregnancy

Question 446

what does relaxin do?

Answer 446

softens the estrogen-primed PELVIC LIGAMENTS

to allow enough stretch for the passage of large head of fetus through the pelvis

Question 447

“supplementary” tropic hormones released by the placenta do what?

Answer 447

stimulate the:

• gonadal
• mammary
• adrenal
• thyroid

functions

Question 448

what are the 4 supplementary protein hormones released by the placenta?

Answer 448

1. chorionic gonadotropins (CG)
2. chorionic somatomammotrophin (CS, aka palcental lactogen)
3. chorionic corticotropin (CC)
4. chorionic thyrotropin (CT)

Question 449

chorionic gonadotropin

Answer 449

hCG

1. maintains corpora luteal function (and progesterone secretion) during pregnancy
2. part of regulatory system that inhibits ovulation during pregnancy

Question 450

if chorionic is in the name…

Answer 450

then it’s produced in the placenta

Question 451

what hormone helps inhibit ovulation during pregnancy

Answer 451

chorionic gonadotropin

hCG

Question 452

gastrointestinal hormones: 3 main features

Answer 452

1. endocrine cells of gastrointestinal tract = scattered throughout gut
   - in a “primitive organization”
2. gastrointestinal hormones regulate cells and organs in which they’re produced
   - intracrine/autocrine chemical mediation is usually considered a more primitive mechanism that endocrine mediation
3. main hormones: secretin, cholecystokinin, ghrelin
   - these hormones = released into circulation and act to supplement the actions of the ANS during digestion

Question 453

endocrine cells of gastrointestinal tract are organized in what fashion?

Answer 453

scattered around the gut

in what is called a PRIMITIVE ORGANIZATION

Question 454

what kind of chemical mediation occurs for gastrointestinal hormones?

Answer 454

intracrine/autocrine chemical mediation

these hormones regulate the cells and organs in which they are produced

Question 455

secretin

Answer 455

small peptide of 27 amino acids

release of secretin by duodenal mucosa = stimulated by passage of food into small intestine

stimulates pancreas to produce secretions which aid in digestion

Question 456

what releases secretin? what stimulates it?

Answer 456

duodenal mucosa

release is stimulated by passage of food into small intestine

Question 457

what does secretin do?

Answer 457

it stimulates the pancreas to produce secretions which aid in digestion

• stimulation of hepatic (liver) tissue
• pepsin secretion
• inhibition of gastrointestinal (GI) tract movement and gastric acid secretion

Question 458

cholecystokinin (CKK)

Answer 458

hormone released by lining of small intestine that may be involved in satiation of food intake

causes exocrine pancreas to secrete digestive enzymes

CKK also causes gallbladder to contract/release bile

Question 459

what releases cholecystokinin (CKK)?

Answer 459

lining of the small intestine

Question 460

CKK causes exocrine pancreas to do what?

Answer 460

secrete digestive enzymes

Question 461

CKK causes gallbladder to do what?

Answer 461

contract/release bile

Question 462

CCK hormone has been identified where outside of the gastrointestinal tract?

Answer 462

in the brain

here it functions as a neurotransmitter or nueromodulator

Question 463

gastrin

Answer 463

peptide hormone

secreted by mucous layer of stomach

induces secretion of water and electrolytes by stomach, pancreas, liver

induces secretion of enzymes by stomach and pancreas

produced in antral glands of stomach

Question 464

gastrin is secreted by…

Answer 464

mucous layer of the stomach

Question 465

what does gastrin do?

Answer 465

induces secretion of:

1. water and electrolytes by the stomach, pancreas and liver
2. enzymes by the stomach and pancreas

Question 466

where is gastrin produced?

Answer 466

antral glands of the stomach

Question 467

what does ghrelin do?

Answer 467

stimulate GHRH from anterior pituitary

Question 468

where is ghrelin made?

Answer 468

endocrine cells in the stomach

Question 469

what happened when ghrelin was administered to mice?

Answer 469

was done to see if it would enhance GH secretion

food intake and fat deposition increased

Question 470

human participants treated with ghrelin…

Answer 470

ate about 30% more food than individuals not given the hormone

concentrations of ghrelin increased to peak levels prior to each meal (~80% increase) and fell dramatically after the meal

Question 471

2 basic patterns of internal hormonal regulation

Answer 471

1. regulation by the physiological by-products generated in response to their actions (thermostat)
2. regulation by the stimulatory or inhibitory effects of other hormones

Question 472

example of regulation of hormones by the physiological by-products generated in response to their actions

Answer 472

ie. parathyroid hormone is released when blood levels of calcium decrease

when the action of the hormone has raised concentration of blood calcium to an optimal level, parathyroid hormone secretion stops

thermostat analogy

Question 473

example of hormonal regulation by the stimulatory or inhibitory effects of other hormones

Answer 473

within this form of control, one or more hormones in a regulatory chain may be involved in hormonal regulation

ie. GnRH is regulated by a multiple chain of negative feedback

Question 474

negative feedback

Answer 474

part of hormonal regulation

a regulatory system that tends to STABILIZE a process when its effects are pronounced by REDUCING ITS RATE/OUTPUT

Question 475

positive feedback

Answer 475

part of hormonal regulation

a regulatory process that tends to ACCELERATE an ongoing process by INCREASING PRODUCTION in response to the end product

generally less frequent - must be tightly controlled

ie. short term stress response can’t be let go on for too long

Question 476

can hormones affect the levels of their own receptors?

Answer 476

yes

through up-regulation or down-regulation

Question 477

up-regulation

Answer 477

process similar to positive feedback

hormone causes INCREASE in production of RECEPTORS for that hormone

Question 478

down-regulation

Answer 478

overproduction of a hormone can cause occupation or REDUCE the number of hormone RECEPTORS

Question 479

cellular and molecular mechanisms of hormone action

Answer 479

hormonal messages/signals evoke intracellular responses via SIGNAL TRANSDUCTION

essentially, the chemical hormonal message is transformed into intracellular events that ultimately affect cell function

Question 480

signal transduction

Answer 480

the way in which hormonal messages/signals evoke intracellular responses

Question 481

signal transduction pathway

Answer 481

sequence of events that begins with a hormone binding to its receptor and ends with the ultimate response in a target cell

Question 482

steroid hormone receptors: signal transduction

Answer 482

steroid hormone receptors = located inside cells (cytosol or nucleus)

steroids = lipid soluble, so can penetrate cell membrane to bind with these intracellular receptors

when the receptors bind to a specific steroid/thyroid hormone, they migrate to nucleus

here, they regulate gene transcription

Question 483

protein and peptide hormone receptors: signal transduction

Answer 483

protein/peptide hormone receptors = embedded in cell membrane

have at least three domains with specific functions

1. extracellular domain (binds to hormone to form hormone-receptor complex)
2. transmembrane domain
3. cytoplasmic/intra-cellular domain (inside cells, often transmits a signal)

Question 484

protein/peptide hormones have two types of activity…

Answer 484

1. intrinsic enzymatic activity
   - have enzymes in the cytoplasmic domain that phosphorylate/activate intracellular proteins
2. require a second messenger
   - these receptors are coupled to G proteins
   - G proteins are activated when the appropriate hormone binds to the receptor
   - this part of the activated G protein activates an effector protein that converts thousands of reactants to products, amplifying action within the cell

Question 485

what is the definition of sex?

Answer 485

several ways to answer this

because there are different levels of sexual determination

each step of mammalian sexual development = a different step in a cascade of events

Question 486

why do sex differences exist?

Answer 486

some species don’t have different sexes: they reproduce asexually

ie. white spotted bamboo shark

but asexual reproduction results in less genetic diversity

so, SEXUAL REPRODUCTION PROVIDES GENETIC VARIABILITY THAT ENHANCES EVOLUTIONARY FLEXIBILITY

through the separation of haploid pairs in parents and their recombination in offspring

combo of genetic info = more flexibility

Question 487

why do sexually dimorphic behaviours exist?

Answer 487

mating system

either MONOGAMOUS or POLYGAMOUS

sex differences = reduced in monogamous species

ie. prairie voles are monogamous: virtually impossible to tell male and females apart

ie. elk are polygamous: males and females are readily distinguishable

Question 488

what kind of mating system causes more sexually dimorphism?

Answer 488

polygamous

Question 489

male bowerbirds: sexually dimorphic behaviours

Answer 489

males compete against one another to win over female mates

male bowerbirds have lots of different mating partners, and females raise offspring alone

so females must choose their mate wisely

males impress them by building colourful, elaborate bowers

Question 490

sexual selection favours sexual ___________ and ____________ it over time

Answer 490

dimorphism

amplifies

Question 491

sexually dimorphic behaviours are products of…

Answer 491

both NATURE and NURTURE

reflect role of biology and environment (socialization)

ie. boys are more likely to play in large groups, rough and tumble activities

ie. girls are more likely to play in twos and threes, more verbal communication

Question 492

4 recaps from beginning of sexual differences lecture

Answer 492

1. sex determination occurs in various steps
2. sexual reproduction favours evolutionary flexibility by providing genetic variability
3. possibly because of the mating system related to sexual reproduction, several behaviours are sexually dimorphic
4. sexually dimorphic behaviours are a product of nature and nurture

Question 493

5 levels of mammalian sexual differentiation

Answer 493

1. chromosomal sex
2. gonadal sex
3. hormonal sex
4. morphological sex
5. behavioural sex

each level affects the next one

Question 494

step 1 in process of mammalian sexual differentiation

Answer 494

chromosomal sex

Question 495

chromosomal sex

Answer 495

defined during fertilization

chromosomal sex of the child = determined by whether the sperm contributes with an X or a Y chromosome (female gametes always contributes an X chromosome)

XX: female
XY: male

Question 496

step 2 in process of mammalian sexual differentiation

Answer 496

gonadal sex

Question 497

gonadal sex

Answer 497

testes or ovaries

each embryonic individual (regardless of chromosomal sex) develops a thickening called the GERMINAL RIDGE

this is a bipotential primordial gonad

expression of SRY gene (found on Y chromosome) produces testis determination factor (TDF)

Question 498

location of germinal ridge

Answer 498

on the ventromedial surface of each protokidney

Question 499

bipotential primordial gonad

Answer 499

this is what the thickening of the germinal ridge gives way to

bipotential: can either turn into ovaries or testes

depends on whether or not there is SRY gene

Question 500

where is the SRY gene found? what does it produce?

Answer 500

found on the Y chromosome

produces TDF (testis determination factor)

Question 501

SRY presence versus absence

Answer 501

presence: will produce TESTIS DETERMINATION FACTOR (TDF)

absence: no testis determination factor

Question 502

testis determination factor (TDF)

Answer 502

produced by the SRY gene

Question 503

SF-1

Answer 503

steroidogenic factor 1 protein

in combination with TDF, produces a transcription factor

this transcription factor regulates expression of SOX9 gene

Question 504

SF1 + TDF =

Answer 504

transcription factor

this transcription factor regulates expression of SOX9 gene

Question 505

protein products of SRY and SOX9 lead to…

Answer 505

development of the middle of the germinal ridge

this forms the testis

Question 506

so development of the testis requires…

Answer 506

SRY gene

TDF

SF-1

transcription factor

SOX9

Question 507

if SRY or SOX9 aren’t produced…

Answer 507

the outer part of the germinal ridge develops

and ovary forms

Question 508

what part of germinal ridge develops if SRY and SOX9 are produced? what about if they’re absent?

Answer 508

if present: middle of the germinal ridge develops (into testis)

if absent: outer part of germinal ridge develops (into ovaries)

Question 509

recent evidence suggests that _______ gene is required for normal ________ _____________

Answer 509

Wnt4 (wingless-related MMTV integration site 4) gene

ovarian development

Question 510

discovery of Wnt4 gene is important because…

Answer 510

used to be thought that mere absence of SRY and SOX9 would cause female development (ovaries)

but turns out there is another gene that probably must be present (Wnt4 gene)

Question 511

step 3 of mammalian sexual differentiation

Answer 511

hormonal secretions

Question 512

hormonal sex

Answer 512

hormonal secretions from the developing gonads determine whether the individual develops in a male or female manner

mammalian embryonic testes produce ANDROGENS

embryonic ovaries of mammals don’t secrete high concentrations of hormones

in presence of ovaries or in complete absence of any gonads, the development follows female pathway

Question 513

androgens =
no gonads/hormones =

Answer 513

male development

female development

Question 514

mammalian embryonic testes produce…

Answer 514

androgens

Question 515

embryonic ovaries don’t secrete…

Answer 515

high concentrations of hormones

Question 516

interesting finding: sexually dimorphic transcription of over 50 genes in brains of mice at 10.5 days post-conception

Answer 516

50 chromosomal genes were different between males and females

even at 20.5 days post-conception

wayyyy before gonads were developed

suggests that sex genes = mediated by chromosomes, not gonads

Question 517

interesting finding: cell culture from XY mice contain more cells expressing tyrosine hydroxylase than XX cultures, irrespective of the gonadal sex of the embryos from which the cells were taken

Answer 517

again, suggests that chromosomes are mediating sex to certain degree

independently from gonads

Question 518

step 4 of mammalian sexual differentiation

Answer 518

morphological sex

Question 519

morphological sex

Answer 519

Mullerian (female) and Wolffian (male) duct systems are normally BOTH PRESENT early in embryonic development

dual anlagen

Question 520

dual anlagen

Answer 520

rudimentary basis of accessory sex organs

apparatus for both male and female accessory organs (“dual”)

both Wolffian and Mullerian

Question 521

Mullerian duct system develops into…

Answer 521

fallopian tubes

uterus

upper vagina

and the Wolffian ducts regress

Question 522

Wolffian ducts develop into…

Answer 522

seminal vesicles

vas deferens

Mullerian system regresses

Question 523

what do male accessory sex organs require?

Answer 523

two products from the embryonic testes

1. testosterone
2. Mullerian inhibitory hormone (MIH)

Question 524

what do testosterone and MIH do, respectively?

Answer 524

testosterone: stimulates Wolffian duct development (masculinization)

MIH: causes regression of the Mullerian duct system (defeminization)

Question 525

what is responsible for the differentiation of the external genitalia?

Answer 525

androgens

Question 526

what happens in the presence of androgens?

Answer 526

1. urethral groove fuses
2. genital tubercle develops into penis
3. genital folds fuse into scrotum

Question 527

what happens in absence of androgens?

Answer 527

1. clitoris develops from genital tubercle
2. vaginal labia develops from genital folds

Question 528

are accessory sex organs differentiated at 6 weeks?

Answer 528

no, they’re undifferentiated

1. genital tubercle
2. urogenital sinus
3. anal fold

Question 529

male versus female external genitalia

Answer 529

male: penis, scrotum

female: clitoris, labia

Question 530

what controls mating behaviour in both sexes?

Answer 530

gonadal steroid hormones

Question 531

castration of male mice - effect on mating behaviour

Answer 531

castrated males stop mounting behaviour

but testosterone replacement therapy restores mounting behaviour to original levels

Question 532

typical female versus male mating behaviour

Answer 532

female: lordosis

male: mounting

Question 533

does injection of adult females with testosterone increase their mounting behaviour?

Answer 533

no, it does not

suggests that at some point in development, female rats lose potential to exhibit male-typical behaviour

Question 534

do males injected with estrogen display female-typical behaviour?

Answer 534

no

Question 535

first study that led to organizational/activational hypothesis of hormonal differentiation

Answer 535

Charles Phoenix

wanted to know at what point differentiation occurs

studied effects of PRENATAL and EARLY POSTNATAL androgen treatment on guinea pigs

on female reproductive behaviour (mounting/lordosis)

did this by observing and manipulating mating behaviour

Question 536

Charles Phoenix study: Phase 1 setup

Answer 536

PHASE 1:
- pregnant guinea pig was injected with testosterone

• some received larger doses than others

Question 537

female offspring from mother with larger dose…

Answer 537

possessed external genitalia indistinguishable from those of brothers/typical males

Question 538

female offspring from mother with smaller dose…

Answer 538

no visible changes to external genitalia

referred to as “unmodified females”

Question 539

Charles Phoenix study: Phase 2 three groups

Answer 539

looked at the adult offspring

1. smaller dose prenatal testosterone exposed females and males
2. bigger dose prenatal testosterone exposed females and males
3. control females and males

Question 540

Charles Phoenix study: Phase 2

Answer 540

all 3 groups were:

1. gonadectomized
2. injected with estrogen and progesterone
   (to stimulate female sexual behaviour)
3. paired with male guinea pig
4. some time later, were all injected with androgens (to stimulate male sexual behaviour)
5. paired with female guinea pig

Question 541

Charles Phoenix study: conclusion

Answer 541

androgens given to guinea pigs prenatally

1. decreased tendency of both experimental groups of females to display lordosis in adulthood
2. increased tendency of both experimental groups of females to display mounting behaviour in response to testosterone therapy
3. caused no deleterious effects on mounting behaviour or other masculine behavioural patterns in males treated

Question 542

Charles Phoenix study: important distinction that emerged

Answer 542

clear distinction can be made between PRENATAL ACTION of HORMONES in causing differentiation/ORGANIZATION of neural substrates for behaviour

and the actions of HORMONES in ADULTHOOD in causing ACTIVATION of these hormones

organization - activation hypothesis

Question 543

Charles Phoenix study led to…

Answer 543

basis for the organizational/activational hypothesis of sexually dimorphic behaviours

Question 544

organizational/activational hypothesis of sexually dimorphic behaviour

Answer 544

1. sex hormones act during prenatal stage to permanently (irreversibly) organize the nervous system in a sex-specific manner
2. during adult life, the same hormones have activation effects

Question 545

cyclic versus tonic gonadal function

Answer 545

cyclic: present in females
- females display cycles of mating behaviour

tonic: present in males
- males display continuous willingness to mate

Question 546

luteinizing hormone (LH) profile in females and males

Answer 546

females:
- pulsatile release
- then negative feedback is broken
- big increase of LH and FSH secretion
- after ovulation, neg feedback returns

males:
- steady pulsatile release

Question 547

gonadal function (LH levels) is driven by…

Answer 547

gonadotropins secreted from the anterior pituitary

GnRH –> LH –> gonadal function

Question 548

luteinizing hormone affects…
differences in males versus females…

Answer 548

testis and ovaries

testis: testosterone
ovaries: estrogen and progesterone

Question 549

in females, the negative feedback control of GnRH secretion is altered on a…

Answer 549

cyclical basis

females escape the negative feedback loop on a cyclical basis

Question 550

process of breaking the negative feedback loop

Answer 550

1. females escape negative feedback loop on cyclical basis
2. estrogen levels increase
3. surge of GnRH is released in response to rising estrogen levels
4. GnRH stimulates the anterior pituitary to release surges of LH and FSH
5. after ovulation, negative feedback mechanisms are engaged

Question 551

how does the negative feedback system work to regulate steroid secretion?

Answer 551

both males and females have this

increasing gonadal steroid concentrations feed back to the gonads, anterior pituitary and hypothalamus

this slows secretion of GnRH, gonadotropins and gonadal steroids

Question 552

atypical sexual development

Answer 552

a lot happens in the process of sexual differentiation

because it’s a complicated process

high potential for atypical development

Question 553

chromosomal to gonadal sex

Answer 553

SRY gene is located on the short arm of the Y chromosome

this gene causes male gonadal development

Question 554

partial expression of SRY gene

Answer 554

leads to incomplete gonadal differentiation

Question 555

chromosomal XY but no SRY

Answer 555

male mice develop ovaries

Question 556

chromosomal XX but inserted SRY gene

Answer 556

female mice develop testes

Question 557

Swyer syndrome

Answer 557

rare disorder

failure of sex glands (testis or ovaries) to develop

in XY individuals that lack SRY gene

without intervention, won’t experience puberty

external female genitalia, but no menstruation

gonads = functionless

Question 558

what is Swyer syndrome classified as?

Answer 558

a disorder of sex development (DSD)

DSDs encompass any disorder in which chromosomal, gonadal or anatomic sex development is atypical

Question 559

how is Swyer syndrome treated?

Answer 559

hormone replacement therapy

Question 560

hormonal to morphological sex

Answer 560

even if individual is XY, testosterone and MIH must be secreted at the correct time

if MIH isn’t secreted at right time, the Mullerian syndrome will develop

depending on hormonal secretion, possible for both systems or for neither to develop

Question 561

intersex

Answer 561

general term used for variety of conditions in which a person is born with reproductive/sexual anatomy that doesn’t fit the typical definitions of male or female

ie. discrepancies between external genitalia and internal sexual organs

ie. when both systems develop in a single individual (can be separate or combined)

Question 562

is intersex considered a medical problem?

Answer 562

no, although it may signal underlying metabolic concern

intersex individuals aren’t in need of medical treatment

although it used to be considered one - “normalization” srugery

Question 563

spectrum of hormonal to morphological sex

Answer 563

two continuum which intersect

1. masculinization to de-masculinization
2. feminization to de-feminization

potential for multiple different outcomes

Question 564

Prader scale

Answer 564

scoring system for grading degrees of genital masculinization

starts at a 0: unvirilized female
ends at 5: completely virilized female

Question 565

completely virilized female

Answer 565

5 on the Prader scale

female who appears externally male at birth with the labial/scrotal sac empty since there are no testicals

Question 566

what is responsible for differentiation of external genitalia?

Answer 566

androgens

and androgenic metabolites

Question 567

what androgenic metabolite of testosterone is critical for genital fusing process?

Answer 567

5 alpha-dihydrotestosterone (DHT)

testosterone is converted to DHT by an enzyme

Question 568

in females, unusually high levels of DHT leads to…

Answer 568

development of male external genitalia

Question 569

5alpha-reductase deficiency

Answer 569

genetic males (XY) with this deficiency are born with:

1. ambiguous genitalia
2. small, undescended testes
3. usually considered females at birth, reared as females
4. at puberty, testosterone masculinizes the body

Question 570

what happens at puberty for XY individuals with 5alpha-reductase deficiency?

Answer 570

at puberty, testosterone masculinizes the body

1. male-typical musculature
2. axillary hair growth
3. genitalia develop to resemble male-typical penis and scrotum

Question 571

Turner syndrome

Answer 571

1. congenital condition
2. individuals LACK an X chromosome (XO) or DAMAGE to second X (or Y) chromosome
3. have female external appearance
4. but ovarian development = usually limited
5. don’t attain puberty without medical attention

Question 572

congenital adrenal hyperplasia

Answer 572

caused by lack of 21-HYDROXYLASE enzyme

leads to overproduction of ADRENAL ANDROGENS

• progesterone also needs 21-hydroxylase in order to create other important hormones

Question 573

does congenital adrenal hyperplasia cause problems in congenital males?

Answer 573

no

Question 574

what does congenital adrenal hyperplasia do to female genitalia?

Answer 574

causes moderate/sever masculinization

Question 575

androgen insensitivity syndrome

Answer 575

functional androgen receptors are absent

XY individuals born with androgen insensitivity syndrome have normal-appearing female external genitalia

but vagina is oftenshort and they’re sterile

are sexed and reared as girls

Question 576

people with androgen insensitivity syndrome are sexed and reared as…

Answer 576

girls

but vagina is short and no menstruation occurs (they’re sterile)

Question 577

when do people discover that they have androgen insensitivity syndrome?

Answer 577

at adolescence

when menstruation fails to occur

Question 578

3 possible trisomic anomalies

Answer 578

1. Klinefelter syndrome (XXY)
2. XYY
3. XXX

Question 579

Klinefelter syndrome

Answer 579

XXY

extra X chromosome

presence of Y chromosome = sufficient for SRY gene to be activated and for masculinization to occur

usually sterile because of reduced sperm production

often severe learning disabilities

Question 580

people with Klinefelter syndrome are sexed as…

Answer 580

males at birth

Question 581

Klinefelter syndrome seems to mainly reflect…

Answer 581

variation in the androgen receptor

Question 582

MODERN organizational/activation hypothesis of sexual differentiation

Answer 582

expands the variables that influence sex differences:
1. genes
2. hormones
3. ENVIRONMENT

expands the amount of time in which organization effects take place
1. extend to pre-pubertal period

essentially, the modern theory sees things as much less fixed (more variables are at work and time period in which they have effects are longer)

Question 583

average sex differences in behaviour often reflect significant overlap between the sexes…

Answer 583

are often greater differences in behaviour BETWEEN INDIVIDUALS OF THE SAME SEX

than between individuals of the opposite sex

considerable overlap between the sexes

Question 584

gender role

Answer 584

what roles society expects genders to perform

Question 585

gender identity

Answer 585

internal and personal process by which individuals come to perceive themselves

what they understand their own gender to be

binary, non-binary and plural

Question 586

sexual orientation

Answer 586

enduring pattern of:

• emotional
• romantic
• and/or sexual

attractions that individuals feel towards people of the same and/or opposite sex