Psychobiology Flashcards
1
Q
dendrite
A
branch that receives information from other neurons
2
Q
soma
A
cell body protecting nucleus and cell content, made of phospholipid bilayer that maintains negative charge of cell
3
Q
nucleus
A
engine, where genetic material is stored and where neurotransmitters are produced
4
Q
axon hillock
A
gatekeeper of transmission
- where soma turns into the axon
- graded potentials summed to determine if action potential will be fired
5
Q
axon
A
long nerve fibre
- conducts electrical signals from cell body
6
Q
myelin sheath
A
coating insulating the axon
- allows for faster signalling
7
Q
nodes of ranvier
A
gaps of axon in between myelin sheath so that the electrical signal can jump between nodes and along axon
8
Q
axon terminal
A
chemical messages released here, presynaptic part of the neuron
9
Q
transfer of signal transfers and receives where
A
axon terminal transmits, dendrites receive
10
Q
Multiple Sclerosis (MS)
A
auto-immune disease where cells fail to myelinate axons
- reduces speed of transmission
11
Q
Multipolar neuron
A
most complex, most common
- one axon, two or more dendrites
12
Q
bipolar neuron
A
single dendrite spine
13
Q
unipolar neuron
A
trigger zone instead of axon hillock, one structure extending from soma
14
Q
classify neurons by function
A
sensory, motor, interneuron
15
Q
sensory neuron
A
activated by sensory input
- vision, photoreceptors
- somatic, mechanoreceptors (touch, pressure)
- auditory, hair cells (vibration)
normally unipolar or bipolar, take information from smaller amount of receptor cells
send information to brain from periphery (afferent signal)
16
Q
motor neuron
A
send information from brain to the periphery (efferent signal)
cell body located in spinal cord
- axon projects to the periphery to control muscles
- multipolar
17
Q
interneuron
A
connect only to other neurons
- in brain
- generally multipolar
- involved in higher order processing, memory or cognition
18
Q
Reflex Arc
A
simple example of neural communication
sensory neurons picks up information –> interneuron sends to spinal cord –> motor neuron causes neuron to fire and move muscles
19
Q
CNS
A
brain and spinal cord
20
Q
PNS
A
somatic, autonomic
21
Q
somatic nervous system
A
controls most peripheral parts of the body (arms and legs)
- brain controls bodily movements via skeletal muscles (efferent)
- transmit sensory inform from periphery to CNS (afferent)
22
Q
autonomic nervous system
A
surrounding the core area of body
- parasympathetic (normal bodily functioning)
- sympathetic nervous system (ready for action)
23
Q
rostral or anterior orientation
A
front of brain
24
Q
caudal or posterior orientation
A
back of brain
25
dorsal or superior
the top of brain
26
ventral or inferior
the bottom of brain
27
sagittal cut
slice from back to front
28
mid-sagittal cut
slice from back to front in the middle
29
coronal cut
slice from side to side
30
axial/horizontal...
sectioning across brain
31
gyrus
ridge on cerebral cortex
32
sulcus
a depression in cerebral cortex
33
fissure
deeper grove in cerebral cortex
34
hindbrain
control of vital functions
- adjacent to spinal chord
main regions
- medulla
- pons
- cerebellum
35
medulla
important for cranial nerve input, autonomic centre for heart rate and blood pressure
36
pons
above medulla, region for cranial nerve integration, respiration
37
cerebellum
fine motor control, bottom and end of brain
- cerebella ataxia occurs with damage to cerebellum
38
midbrain
relay station, relays information between hindbrain and forebrain
main regions
- tectum
- tegmentum
39
tectum
superior colliculus
- visual processing and control of eye movement
inferior colliculus
- auditory processing
40
tegmentum
unconscious processes, movement
41
forebrain
rostral
main regions
- hypothalamus
- thalamus
- amygdala
- hippocampus
- cerebral cortex
42
hypothalamus
controller of endocrine system
- pituitary releases hormones and hypothalamus regulates what comes out of pituitary glands
HPA axis
- neurons such as CRF of CRH which are released into pituitary which then release ACTH (adrenocorticotropic) which release glucose
- important for stress response, critical for homeostasis
43
thalamus
important relay for sensory signals to cerebral cortex
- filter, determine what is important, judging sensory overloads
44
amygdala
emotions and fear responses
45
hippocampus
MEMORIES (how they are formed and stored)
- Patient H.M.
if removed - anterograde and partial retrograde amnesia, no effect on working memory and procedural memory
- Morris Water Maze Research -
animal trained where platform is, made blind and forced to find platform, at different insertion points it will find it faster, damaged hippocampus affected performance
46
frontal lobe
executive function, abstract thinking, problem solving, impulse control
- primary motor cortex (for skeletal movement)
- prefrontal association area, coordinating information from other areas
47
how to tell differences between different lobes
- frontal and parietal lobe are seperated by central sulcus
- the temporal lobe is where the lateral fissure is
48
Phineas Gage
- rod through head hitting frontal lobe
- unreliable, callous, hypersexual, poor socially, lack empathy
49
Frontal Lobotomy
- white matter was severed from rest of brain (which connected frontal lobe)
- produced state of plasticity
50
parietal lobe
involved in somatosensory cortex (interpretation)
- overrepresented areas that touch the world, mouth, feet, hands - think sensory homunculus
51
occipital lobe
visual processing through the visual cortex
52
temporal lobe
primary auditory cortex and primary olfactory cortex
- smell and hearing
53
corpus callosum
white matter tract (myelinated axons) that connect the two hemispheres
- allows rapid communication between hemispheres of brain
54
Split Brain Patients
- severed right and left hemispheres from each other, corpus callosum severed
- input in left field
- patients tested on tasks concerning what they see in left and right visual fields to judge if their regions can share information to either sides
55
synapse
chemical or electrical messages betweem neurons
- presynaptic sends and postsynaptic receives
- mainly chemical in humans
56
electrical synapse
- gap junctions, faster
- synapse is closer together
- less common, occur during development
- ions flow through gap junction channels
57
chemical synapse
slower, more processes for signal
- complex connection
- common
58
Steps of Synaptic Communication 1-3 (calcium example)
1. nerve impulse (action potential) at axon terminal
2. voltage-gated (that open in response to electrical charge) calcium channels open, calcium floods into cell
3. after channels open, increased calcium levels flow into cell and activate synaptic vesicles (that house neurotransmitters), activation of vesicles leads to release of neurotransmitters into synaptic cleft
59
Steps of Synaptic Communication 4-6 (calcium example)
4. neurotransmitter in synaptic cleft is free to bind to receptors on postsynaptic neuron
5. when neurotransmitter binds to receptor, a ligand-gated ion channel opens
a) excitation - sodium enters
b) inhibition - other combinations opens different channels
6. excitation or inhibition is known as postsynaptic potential (graded potential)
60
after neurotransmitter released into synaptic cleft:
generally returned to presynaptic cell (neurotransmitter reuptake)
61
forms of synaptic communication
axodendritic - axon terminal will synapse at dendrite
axosomatic - will synapse onto the synapse directly
axoaxonic - synapsing axon to axon, potentially to reduce the output of these neurons
62
graded potentials
graded potential refers to changes in the membrane potential (or the difference in electrical potential inside and outside the cell) that vary depending on the size of the stimulus
- neurons get information from other cells at synapse, changing the electrical charge of the cell membrane on the postsynaptic neuron
- they move across the cell membrane towards the axon hillock, therefore they get a summation of all information they have received, information for IPSP and EPSP adds up (can cancel out)
63
action potential ( or nerve impulse)
An action potential is a rapid, electrical signal that travels down a single cell, changes in voltages across voltage
an action potential will only fire once the membrane potential threshold is reached at the axon hillock
all or nothing phenomenon
64
how charges move around cell membrane:
permeable membrane
electrical potential difference
cells will undergo a shift in electrical charge to have more or less negative charge inside the cell than outside
they do this through two things
- permeable membrane
- electrical potential difference
65
depolarisation
positively charged sodium takes over negatively charged potassium inside the cell, making it positively charged
66
hyperpolarisation
negative potassium takes over positively charged cell after sodium takes over by inhibiting action potential by increasing the stimulus to reach the action potential threshold
67
refractory period
excitation reaches resting potential
68
overshoot
when mV reaches above 0
69
three criteria to be a neurotransmitter
- must be present within the presynaptic neuron
- must be released in response to presynaptic depolarisation and is Ca+ dependent
- specific receptors must be present on postsynaptic cell
70
neuromodulator
when neurotransmitter is not returned to presynaptic cell
- travels to adjacent cells to modulate their activity
occurs in
- monoamine neurotransmitters, in the cholinergic system and with neuropeptides
71
classifying basic receptor functions
ionotropic and metabotropic
72
ionotropic
- ligand-gated ion channels neurotransmitter binds, ion channel opens
- rapid effect
- generates EPSPs and IPSPs
73
metabotropic
g-protein coupled receptors (GPRCs)
- large number with no identified function
- it will bind at a receptor site, release protein
- essentially same effect, but as more is happening it tends to be slower
74
features of GPCRs
- intracellular messengers, could alter gene expression or the cell itself
- slow/long acting
- they can activate enzyme cascades
75
amino acid neurotransmitters
glutamate, GABA (gamma-aminobutyric acid)
76
cholinergic neurotransmission (acetylcholine)
nicotinic acetylcholine receptors
- ionotropic
muscarinic acetylcholine receptors
- metabotropic
77
glutamate
primary excitatory neurotransmitter
- estimated ~50% of synapse utilise glutamate
three ionotropic receptor types
- AMPA (initiating EPSPs)
- Kainate (initiating EPSPs)
- NMDA (neuroplasticity and learning)
77
glutamate-driven long-term potentiation (LTP)
synaptic connections between become stronger with frequent activation/occurence
- - AMPA receptors generate EPSPs
- NMDA receptors increase the number of AMPA receptors at the synapse
- Synaptic connection become stronger, more EPSPs generated
77
Hebb's Law:
cells that fire together, wire together
- when cells are simultaneously activated they form stronger connections
- this is the basis for learning and memory
- concerning neural and synaptic plasticity
78
glutamate and learning conditioned responses
when a sea slug withdraws their gills they use NMDA
when they are put in a threat situation they withdraw
They were given an aversive stimuli to get them to withdraw their gills and then a neutral stimuli
- tail shock (the aversive one)
- syphon tap
it was done at the same time, and then they tapped the sypon alone
- they found the same gill withdrawal response
- therefore learning is dependent on glutamate signalling
79
GABA
gamma-aminobutyric acid
- primary inhibitory neurotransmitter
- brain produces GABA from glutamate, byproduct
- estimated that ~25-40% synapses are GABAergic
GABAa receptor
- ionotropic
- multiple binding sites
- chloride ion channel
- early anti-seizure medications reduced neuronal firing by potentiating the effects of GABA
GABAb receptor
- metabotropic
80
monoamine neurotransmitters
catecholamine (including dopamine, adrenaline/noradrenaline), serotonin, histamine
81
Dopamine (monoamine)
receptors d1-d5
- g-protein coupled receptors
- involvement in reward system, ventral tegmental area (VTA) to the nucleus accumbens
- involved in motor function, substantia nigra to the striatal pathway
82
Olds and Milner (1953) Dopamine Study
- Rats preferred the part of the cage where they were when they received electrical stimulation to the medial forebrain bundle
- They would quickly learn to press a level to obtain this stimulation, later found to be the VTA
- The desire to stimulate this region is so strong an animal may starve itself
- Later work established that stimulation to this region leads to dopamine release
83
Dopamine Parkinson's Disease
- Movement related disorder, shaking and slow movement
- Caused by destruction of the dopamine producing cells of the substantia nigra
- Early idea for treatment: increase levels of dopamine (L-DOPA) - effect could only last so long due to neuronal loss
84
adrenaline/noradrenaline
- Alpha (1-2) and beta (1-3) receptors
- metabotropic g-protein coupled receptors
- A major neurotransmitter associated with sympathetic nervous system activation and the cardiovascular system
- Also a stress hormone involved in fight-or-flight
- Within the CNS
- Responsible for vigilant concentration, in important situations
85
Serotonin (5-HT)
- lots of receptors
- all metabotropic except 5-HT 3 (ionotropic)
- diverse range of function
- mood disorders --> major depressive orders, most pharmacological treatments target this system (reuptake inhibitors)
involved in
- appetite
- sleep
- cognitive function
- important outside of the brain as well
86
histamine
- receptors metabotropic, h1-4
- sleep-wake cycle
- histamine neurons are continuously firing during our waking hours, drops down by 75% during slow wave sleep, stops completely during REM
87
peptide neurotransmitters
endorphins, oxytocin, neuropeptide Y, angiotensin II, corticotrophin-releasing factor (CRF)
- they are not lipid soluble (they cant freely pass the phospholipid bilayer), work by acting in the cell
88
endorphins
located within the autonomic nervous system released from the pituitary to inhibit pain signalling broadly across the body, the somatic nervous system where they inhibit sensory pain signalling, within other brain centres mediating subjective pleasure
- "endogenous morphine"
- g-protein coupled receptors
- function to block pain and induce pleasure
89
oxytocin
love hormone
- pair bonding
involved in social and maternal bonding
90
neuropeptide Y
- drives appetite
- elevated NPY leads to an obese phenotype
- genetically removing NPY receptors prevents diet-induced obesity
91
angiotensin II
- involved in thirst, drinking, hypertension and body fluid homeostasis
- drives hypovolemic thirst
- stimulating ang II induces drinking
92
corticotrophin-releasing factor
- involved in the stress response, HPA axis
- causes ACTH production and release from pituitary
- suppresses appetite
- increases feelings of anxiety
93
drug
exogenous chemical that significantly alters function of cells in the body when taken at low doses (external to internal)
94
burdens of drug use and abuse
social acceptability, economic cost
95
agonist
chemical binds to a receptor, activates the receptor and produces biological effect, more activity at that receptor
96
antagonist
chemical binds to a receptor, prevents agonist-mediated effects, blocked activity at receptor
97
enzyme inhibitors
molecules that prevent enzymes from working normally
98
pharmacodynamics
physiological effects of the drug on the body
99
pharmacokinetics
effects of the body on the drug, such as metabolism
100
routes of drug administration
intravenous; into vein
intraperitoneal; into the gut
subcutaneous; under the skin
intramuscular; into muscle
inhalation; into lungs
topical; through skin
oral; via mouth
101
tolerance
repeated administration results in diminished effect (or requires increased dosage to maintain effect)
- goes in hand with **withdrawal** effects
sensitisation: repeated administration results in heightened effectiveness of the drug
102
antidepressants
monoamine oxidase inhibitors
- Prevent breakdown of monoamine neurotransmitters
- Monoamine oxidase metabolises these neurotransmitters, meaning when these are blocked there are more available to the cell
tricyclic antidepressants
- Inhibited reuptake of serotonin (5-HT) and norepinephrine (NE), more of these in the synaptic cleft, more of these neurotransmitters to bind
SSRIs (selective serotonin reuptake inhibitors)
- inhibited reuptake of 5-HT
- Specifically blocked the SERT (serotonin transporter)
103
antipsychotics
Typical
- D2 receptor antagonist, block dopamine receptors as they sit on the D2 receptors,
- Extrapyramidal side effects, like parkinsons, as movement is a key function related to movement that overactivated dopamine activity to the frontal lobe
Atypical
- Dual D2 and 5-HT2 antagonist
- Would bind at the receptor less tightly and would be released faster from binding site, creating less side effects
104
anxiolytics
- work at GABAa receptor
- work at benzodiazepine
105
depressants
- sedative/hypnotics
- narcotics
- work at GABAa receptor
- alcohol: depressant due to its effect on GABA signalling and inhibition of glutamate signalling
- opiates and opioids: therapeutic opium poppy use predates recorded history, to treat acute pain, commonly abused drug dependence common
106
other types of drugs
mood stabilisers, stimulants, hallucinogens
107
hormone
chemical messengers, generally synthesised by specialised glands, carried by the circulation to target tissues and organs
- vary throughout the day
108
neural communication
direct communication between neurons, rapid, all or none phenomenon
109
endocrine communication
hormone sent out and acts on receptors for that particular hormone, signal travels everywhere, slower, graded strength
110
types of hormones
peptide hormones, steroid hormones, amine hormones (composed of a single amino acid modified into a related molecule)
111
peptide hormones
composed of strings of amino acids
- protein hormones
- enzyme leave "prepro" and "pro" hormones to their active form
- migrate to transport vesicles
- packaged into secretory vesicles
- released by exocytosis from cell membrane
112
steroid hormones
produced from cholesterol --> specific steroid
- produced in gonads or adrenal glands
- released by diffusion from the cell
- lipid soluble
113
amine hormones
derived from amino acids
- base products formed into proteins
- release similar to peptide hormones (by exocytosis)
114
how are hormones signalled throughout the body
- Endocrine or neuroendocrine cells release hormones into the bloodstream (primary mechanism)
- autocrine vs paracrine signalling
- Paracrine hormones act locally on adjacent cells, generally providing negative feedback
- Autocrine signals provide feedback to the cell from which they were released
115
hormones altering cellular function
Act at receptors to alter cell function, change what is being produced
promote the proliferation, growth and differentiation of cells
modify the activity of the cell
116
inputs controlling secretion of hormones
secretion: when substances are discharged from the cell
endogenous factors
- Changes in circulating concentrations of ions (Na+) or nutrients (glucose)
- Direct innervation from the nervous system
- Another hormone acting on endocrine cell
117
stressors
- things that cause stress to an organism
- can be acute or chronic
- both lead to the activation of the sympathetic nervous system and HPA axis
118
HPA-axis
stress response
CRF --> pituitary --> ACTH --> adrenal cortex --> glucocorticoids --> regulate of brain and peripheral function
119
how does the somatic nervous system control body movement
- brain receives somatosensory input
- information is integrated and the motor cortex initiates action
- somatic motor neurons control the actions of muscles
120
what do IPSPS and EPSPs refer to (graded potential)
in reference to potentials of electrical conductance of the cell:
decrease in voltage are inhibitory postsynaptic potentials (IPSPs)
increase in voltage are excitatory postsynaptic potentials (EPSPs)
121
what is the membrane resting potential and threshold
- membrane resting potential is ~-70mV
- membrane threshold is ~-55mV
122
how does a permeable membrane help charges move around the cell
permeable membrane
- the phospholipid bilayer prevents ions from moving around freely
a permeable membrane means ions would diffuse (from higher concentration to lower concentration) evenly
outside cell (extracellular space) there is a lot of sodium
- it is trying to get into the cell through ion channels
- inside the cell (intracellular space) there is a lot of potassium
- is close to equilibrium potential and wants to leave (-90mV)
- more permeable than sodium
123
how does electrical potential difference help charges move around a cell
electrical potential difference
- positive ions are drawn to negatively charged space
- there is a lot of potassium in the cell which is positively charged, and there is a lot of sodium outside of the cell which is negatively charged
- they may try to reach an equilibrium by leaving and entering the cell
124
what is the role of the cholinergic system in different nervous systems
transmission system for somatic nervous system and is a major component of the autonomic nervous system
widely expressed in CNS, projections through forebrain and the hindbrain
- within the CNS the forebrain cholinergic system is associated with cognitive function
- 4/5 approved medications for the side effects of Alzheimer's disease act on the cholinergic system
125
Extracellular space outside of a cell contains a lot of ________
sodium
126
Intracellular space inside of a cell contains a lot of _______
potassium
127
what types of hormones are lipid soluble
steroid neurotransmitters are lipid soluble
peptide and amine transmitters are not, they bind with receptors that allow them to transit signals as opposed to the cell itself
128
phospholipid bilayer characteristics
- maintains negative charge of the cell
- prevents ions from moving around freely
129
gap junction
membrane channel between cells where substances can be exchanged from one cell to an adjacent one
130
exocytosis
way of transporting cell contents to something outside of cell
- fusion of secretory vesicles (things leaving the cell) with a plasma membrane
- hormones do this when they are not lipid soluble
131
what are the two catecholamine neurotransmitters
adrenaline, dopamine
132
correct order of the process of an action potential
depolarisation - repolarisation - hyperpolarisation - refractory period
133
afferent
periphery to brain
134
efferent
brain to periphery
