Unit 4 - Homeostasis Flashcards
homeostasis
constant physiological adjustments of the body in response to external environment changes.
negative feedback system
positive signal, physiological change, neg signal
positive feedback (feed-forward) system
ex. contractions
positive signal, physiological change, positive signal
endocrine system
delivery of chemicals within the body; created by one organ to be delivered to another (usu far away)
hormones
affecting chemicals delivered around the body; to increase / decrease processes
glands
they secrete
endocrine glands
organs producing molecules delivered by bloodstream (inside)
exocrine glands
organs producing molecules delivered by ducts (cellular tubes) (outside)
hormone discovery
Mering & Minkowski removed pancreas from dogs - rapid weight loss - tired - glucose in urine (pancreas related to regulating body sugars)
hormone roles
hormone are specific to target cells (protein receptors)
two types of hormoens
- steroid hormones
2. protein hormones
steroid hormones
- made from cholesterol
- non-polar (need carrier)
- 3 hexagons and 1 pentagon
1. diffuse from cell of origin through membranes
2. diffuse into target cell
3. often moves into nucleus to affect transcription
LDL
HDL
info abt cholesterol
low density lipoproteins
high density lipoproteins
cholesterol is hydrophobic (packaged in protein “capsule”)
cholesterol is lower density than protein
steroid hormones can affect ____ and how
transcription
they find sequence in promoter region to bind to, 2 hormones bring 2 receptors together, recruit transcription factors and affect transcription
protein hormones
- short peptide sequences
- polar
1. transported from cell of origin (secretory vacuoles)
2. attach to surface receptors of target cells
3. activates enzymes to make other internal signals
pituitary gland
overlooks operation of all other glands
2 lobes in pituitary gland
close to hypothalamus
- anterior lobe - produces own hormones; released upon hypothalamus signal (front)
- posterior lobe - stores and releases hormones produced in hypothalamus; released upon signal (back)
thermoregulation
maintenance of body temp within an acceptable range
ectotherms - cold-blooded
endotherms - warm-blooded
what happens when you’re cold
- blood vessels contract in skin
- muscles contract (goosebumps, shivering)
- brown adipose (fat) tissue metabolism (high [mitochondria] for heat, newborns have so don’t shiver)
what regulates our temp
hypothalamus
heat stress flow chart
high body temp ->
hypothalamus (+) ->
nerve pathway (+) ->
- blood vessels dilate; increased blood flow; heat leaves skin
- sweat glands induced; sweat evaporation
- > body temp drops (-)
why frostbite
prioritize important organs
cryopreservation
suspending life through freezing
- frozen cytosol can expand to break the cell membrane
some human parts can be preserved: semen blood tissue samples eggs
frozen wood frogs
able to freeze whole body and survive
organs responsible for excretion
liver
kidneys
bladder
excretion
removal of metabolic wastes
- not feces (not used, therefore not metabolic waste)
urine
solution of metabolic waste - urea and uric acid - salts - organic compounds - water fluid for urine come form filtered blood and extracellular fluid (ECF) which surrounds cells
urea
product of NH3 and CO2
deamination - removal of amine group (NH3 released when liver breaks down proteins)
reacts w CO2 to produce less toxic urea
uric acid
product of nucleic acid (purine bases) breakdown
released through liver metabolism
role of kidneys
urea and uric acid are filtered through the kidney
how do amoeba remove waste
contractile vacuole
how do earthworms remove waste
secretion
how do fish remove waste
excrete ammonia through gills
how do birds remove waste
excrete uric acid with feces
renal system
referring to the kidney
role of kidney
- blood filtration
- waste excretion
- acid/base balance
- blood pressure regulation
- hormone secretion
kidney blood flow
blood enters the kidney through the renal artery
- renal arteries stem from the aorta
filtered blood exits the kidney through the renal vein
- renal veins flow into the inferior vena cava
renal artery blood is filtered through ___
nephrons
abt a million nephrons make up the kidney
nephrons
nephrons collect liquids to be excreted
fluids are exchanged btw the nephron before blood is returned to renal vein
- the renal artery is split into ___
- blood goes to ___
- blood leaves through ___
- afferent arterioles
- glomerulus (capillary bed)
- efferent arterioles
(no veins involved!)
efferent arterioles are the beginning of a network of ___ that wrap around the ___
peritubular capillaries
nephron
nephrons begin surrounding the glomerulus with the ___ structure
+ the next four steps
Bowman’s capsule
- fluids to become urine flow to narrow proximal tubule
- urine goes through loop of Henle
- urine goes through distal tubule
- urine from multiple nephrons go into collecting duct
space-interstitial fluid
Extracellular fluid space, around loop of Henle
kidney structure
renal cortex - outside of kidney; location of Bowman’s capsule
renal medulla - middle of kidney; location of loop of Henle
renal pelvis - location of the ends of collecting ducts
urine flow
urine leaves the renal pelvis through the ureters and travels to the bladder. fluid leaves body through urethra.
at ___ of urine in bladder, walls stretch and signals are sent to the brain
at ___, urine will be involuntarily released
~200mL
~600mL
urinary tract infection (UTI)
caused by bacterial growth in the urethra or bladder
symptoms of UTI
- frequent urination
- sensation of needing to urinate
- blood in urine
- discharge in urine (cloudy)
nephron structure
(check diagram) efferent arteriole afferent arteriole glomerulus Bowman's capsule proximal tubule loop of Henle distal tubule collecting duct
urinary system
(check diagram) aorta inferior vena cava renal artery renal vein kidney ureter bladder urethra
renal cortex renal medulla renal pelvis nephrons ureter
three functions of urine formation
- filtration - movement of fluids from the glomerular blood to the Bowman’s capsule
- reabsorption - transfer of fluids from nephron into peritubular capillaries
- secretion - transfer of fluids from peritubular capillaries into nephron
filtration
nutrients move from glomerulus into Bowman’s capsule due to high blood pressure
(65 mm Hg; normal ~25 mm Hg)
bigger molecules are filtered (H2O, NaCl, NOT platelets/red blood cells)
reabsorption
saves fluids for our body, takes back water and nutrients
- 20% of fluid flowing into kidney is filtered into nephrons
- less than 1% of nephron fluid is used to make urine
reabsorption vs secretion
reabsorption
- protein transporters move nutrients into interstitial fluid and blood (btw capillaries and tube)
- kidney tissues will only reabsorb a certain level of nutrients - threshold level
secretion
- protein transporters move wastes from blood to interstitial fluid to nephron
order of nephron structures
- Bowman’s capsule
- proximal tubule
- loop of Henle - descending limb
- loop of Henle - ascending limb
- distal tubule
- collecting duct
bowman’s capsule
filtration
water and dissolved solutes leave glomerulus; enter Bowman’s capsule
proximal tubule
selective reabsorption of nutrients (need transporters)
pH determined by HCO3- reabsorption of H+ secretion
loop of Henle - descending limb
only permeable to H2O (osmosis)
impermeable to salt
fluids in tube are being concentrated
loop of Henle - ascending limb
only permeable to salt (need ionic transporters)
impermeable to water
(when salt is reabsorbed, water follows from the descending limb and the flow continues)
distal tubule
selective reabsorption of nutrients (need transporters)
pH determined by HCO3- reabsorption and H+ secretion
collecting duct
urine formation by concentration of nephron fluid
any urea and urine that is reabsorbed is less than that was filtered into nephron
cortex & medulla in the nephron
cortex: - proximal tubule - distal tubule medulla: - loop of Henle (both) - collecting duct
kidney stones
crystallization of some urine solutes
2-3mm stone can obstruct flow to ureter
treatment:
- increased water consumption
- surgery
three physiological characteristics controlled through the kidney
- osmotic pressure
- blood pressure
- pH balance
osmotic pressure
water pressure due to the presence of solutes
antidiuretic hormone (ADH)
regulates blood osmotic pressure through kidneys
short peptide hormone
produced in hypothalamus, transported to pituitary gland
when would osmotic pressure be increased
sweating/dehydration
increased ADH production leads to (2)
increase water resorption
dilute solutes in blood
osmoreceptors
located in hypothalamus
detect increased osmotic pressure, sends signal to pituitary gland
osmotic pressure (flowchart)
increased osmotic pressure ->
osmoreceptors (+) ->
pituitary gland; release ADH (+)->
- increased sensation of thirst
- increased water reabsorption by kidney
decreased osmotic pressure (-) ->
ADH increases H2O reabsorption, so
dilutes blood
concentrates urine
what part of the nephron does ADH affect
collecting ducts
hormones only active when ___
hormones usually produced, but activated by ___
hormones _______ rather than waiting for transcription/translation
needed
enzyme cleavage
readily available
blood pressure
increase force of blood on blood vessels
increase osmotic pressure, increase blood pressure
aldosterone
steroid hormone which increases Na+ reabsorption in kidneys
- increased H2O in blood
- increased blood pressure
produced in adrenal gland (above kidney)
decreased water pressure is detected by ______
juxtaglomerular apparatus (receptors next to the glomerulus)
what enzyme is released w low blood pressure
renin
what does renin do
angiotensinogen ->
angiotensin
functions of angiotensin (2)
- causes blood vessel constriction
2. stimulates aldosterone release
blood pressure (flow chart)
low blood pressure ->
juxtaglomerular apparatus (+) ->
cells to release renin; produce angiotensin (+) ->
- constrict blood vessels
- induce aldosterone release; increase Na+ reabsorption
blood pressure increases (-) ->
buffers
conjugate acid-base pairs
solutions w solutes + strong acid/base ->
no significant change
conversion of CO2 to other compounds help regulate blood pH
H2O + CO2
H2CO3
HCO3- + H+
H2CO3 - carbonic acid
HCO3 - carbonate ion
HCO3- is reabsorbed in the proximal and distal tubules
in pancreas:
two cell types? what do they make
digestive enzymes - exocrine acini
hormones - islets of Langerhans
what % of pancreas are the islets of Langerhans
1-2%
what two hormones are made in islets of Langerhans? by what type of cell?
- insulin - beta cells
2. glucagon - alpha cells
insulin function flowchart
hyperglycemia ->
beta cells (+) ->
cellular signals for insulin release (+) ->
- increased glucose uptake
- glycogen production in liver
decreased blood sugar (-) ->
glucagon function flowchart
hypoglycemia ->
alpha cells (+) ->
cellular signals for glucagon release (+) ->
- glucose release from liver
- glucose production in liver
increased blood sugar (-) ->
types of diabetes (3)
- Diabetes Mellitus - Type 1
- Diabetes Mellitus - Type 2
- Diabetes Insipidus
Diabetes Mellitus - Type I
aka, cause, symptoms, treatment
aka juvenile diabetes
Cause
- immune system attacking insulin-producing beta cells
Symptoms
- increased thirst, hunger, and urination
Treatment
- daily dosage of insulin
Diabetes Mellitus - Type II
formerly known as, cause, symptoms, treatment
formerly known as adult-onset diabetes
Cause
- insulin resistance/deficiency
Symptoms
- increased thirst, hunger, and urination
- fatigue/lethargy
Treatment
- healthy diet and exercise
- medication only upon progression of disease state
Diabetes Insipidus
cause, symptom, treatment
Cause
- deficiency of ADH
Symptoms
- excessive thirst and urination
- reduction of fluid intake does not affect urination frequency
- no increased blood glucose
Treatment
- ADH replacement/stimulating medication
insulin isolation
- tied off ducts to digestive tract
- cell producing digestive enzymes shriveled
- only islets of Langerhans remained
hormone type of insulin and glucagon
peptide hormone
adrenal meaning
“next to” to the renal system
two main sections of adrenal glands
- adrenal cortex (long-term stress) (outside)
2. adrenal medulla (short-term stress) (inside)
adrenal cortex
what happens when theres long-term stress?
long-term stress sends ACTH (adrenocorticotropic hormone)
pituitary -ACTH-> adrenal cortex
makes hormones (2):
- glucocorticoids
- mineralcorticoids
glucocorticoids
class of steroid hormones for glucose regulation, ex. cortisol
when stressed out:
- glucose not taken in by muscles
- amino acids made into glucose
- fat tissue broken down for energy
mineralcorticoids
class of steroid hormones for mineral regulation, ex. aldosterone
when stressed out:
- blood pressure rises due to increase sodium & H2O reabsorption
adrenal medulla
what happens when theres short-term stress
short-term stress detected by hypothalamus
makes hormones (2):
- epinephrine (adrenaline)
- norepinephrine (noradrenaline)
what are epinephrine and norepinephrine
both are catecholamines, also neurotransmitters
type of hormone
epinephrine and norepinephrine
polar, amino acid-like
flight/fight/freeze response
- increased heart rate
- increased breathing
- blood vessel dilation -> more O2 delivery
- iris dilation -> collect max visual info
induced by catecholamine release
three glands that help regulate metabolism
- thyroid gland
- parathyroid gland
- anterior pituitary
thyroid gland
- regulates glucose metabolism
- regulates growth and tissue differentiation
- base of neck, anterior to larynx
thyroid gland produces 2 hormones
what do both contain
- thyroxine (T4)
- iodothyronine (T3)
both contain iodine
both T3 & T4 are derived from ___
the amino acid tyrosine
hormone type
T3 & T4
hydrophobic
thyroid hormone regulation
signal? - change in metabolic rate What detects? - hypothalamus - releases thyroid-releasing hormone (TRH) to signal to the pituitary What does TRH do? - signals pituitary to release thyroid stimulating hormone (TSH)
thyroxine regulation flowchart
decreased metabolism ->
hypothalamus (+) -> TRH
pituitary gland to release TSH (+) ->
thyroid gland to release thyroxine (+) ->
increase sugar metabolism
decreased blood sugar (-) ->
thyroid disorders
- hyperthyroidism
- hypothyroidism
- goiters
hyperthyroidism
cause, symptom, treatment
high thyroxine release
Cause
- “hot” nodules/Grave’s disease (whole thyroid)
Symptoms
- high glucose metabolism
- > weight loss with increased appetite
- > anxiety
- > increased heat release
Treatment
- suppressive medication
hypothyroidism
cause, symptom, treatment
low thyroxine release
Cause
- iodine deficiency
Symptoms
- low glucose metabolism
- > weight gain
- > fatigue
- > decreased heat release
Treatment
- synthetic hormone medication
goiters
low iodine levels result in enlarged thyroid glands
why is table salt iodized
to prevent iodine deficiency
where is calcium stored
99% is stored in bones for structure
roles of calcium
- required for muscle contraction
- important in neuronal communication
- bone structure maintenance
bone structure
osteoblasts & osteoclasts
osteoblasts - cell which build bones
osteoclasts - cells which break down bones (release calcium)
parathyroid glands
smaller glands within the thyroid gland
increases Ca2+ levels in blood
produces parathyroid hormones (PTH)
calcium level regulation flowchart
hypocalcemia -> parathyroid gland (+) -> release PTH (+) ->
- increased Ca2+ uptake in intestines (diet) & kidneys (reabsorption)
- increases osteoclast activity
- activation of vitamin D; required for Ca2+ absorption
increased Ca2+ levels ->
what are responsible for decreasing high calcium levels
different organ and hormone responsible from increasing Ca2+
organ = thyroid hormone = calcitonin
calcium level regulation flowchart
hypercalcemia -> thyroid gland (+) -> release calcitonin (+) ->
- inhibits Ca2+ absorption by intestines
- decreases osteoclast activity
decreased Ca2+ levels (-) ->
type of hormone
PTH, calcitonin, vitamin D
peptide
peptide
steroid-based
parathyroid disorders
- hypoparathyroidism
2. hyperparathyroidism
hypoparathyroidism
cause, symptom, treatment
Cause
- absent parathyroid from birth
- accidental removal upon thyroid removal
Symptoms
- decreased Ca2+ levels in blood
- sensitive nerves
- uncontrollable spasms of the limbs
Treatment
- daily calcium and vitamin D supplements
hyperparathyroidism
cause, symptom, treatment
Cause
- tumors on the parathyroid gland
Symptoms
- kidney stones
- aches & pains
- osteoporosis
- depression & fatigue
Treatment
- removal of parathyroid tissue
gonadotropic hormones
regulate gonad development (male and female)
produced in the pituitary; released upon hypothalamus signal
other reproductive hormones
- follicle stimulating hormone (FSH)
2. luteinizing hormone (LH)
male reproductive hormones (2)
type
made where
- androsterone
- testosterone
both steroid
made in testes
types of testes cells (2)
- Leydig interstitial cells - make hormones
2. Sertoli cells - make sperm
male gonad development
- hypothalamus secretes gonadotropin-releasing hormone (GnRH)
- pituitary gland releases FSH & LH
- FSH stimulates Sertoli cells to make sperm
- LH stimulates Leydig cells to secrete testosterone
role of testerone
- stimulates spermatogenesis (life time process)
- develops male characteristics at puberty
- increased secretion of body oils (commonly associated to body odour)
male reproductive system flowchart
refer to diagram
female reproductive system hormones
- estrogen (steroid)
- progesterone (steroid)
both made in the ovaries
ovary follicle cells (2)
- primary oocyte - fertilized by sperm
2. granulosa cells - provide nutrients for primary oocyte
female reproductive system
- monthly cycle until menopause (~12-50 yrs)
- one ovum produced per germ cell
- female hormones responsible for oogenesis and ovulation
menstrual cycle
- menstruation (flow phase)
- follicular phase
- ovulation
- luteal phase/secretory stage
menstrual cycle -
1. menstruation (flow phase)
- sloughing of endometrial cells
- no ovum fertilization
- estrogen and progesterone levels low
menstrual cycle -
2. follicular phase
- follicle maturation
- estrogen secretion by granulosa cells
menstrual cycle -
3. ovulation
- ovum leaves ovary
- granulosa cells become corpus luteum
- corpus luteum begins to secrete progesterone
- estrogen levels decrease
menstrual cycle -
4. luteal phase/secretory stage
- corpus luteum secretes progesterone & estrogen
- progesterone encourages endometrium development
female gonad development
- GnRH, FSH, and LH involved
1. hypothalamus secretes gonadotropin-releasing hormone (GnRH)
2. pituitary gland releases FSH & LH
3. FSH matures follicle
4. LH causes ovulation and causes corpus luteum maturation
female reproductive system flowchart
check diagram
menopause
- ovaries lose responsiveness to FSH and LH
- usu occurs btw ages 46 and 54
- most other mammals do not undergo menopause
major subsystems in vertebrate nervous systems (2)
- central nervous system (CNS)
2. peripheral nervous system (PNS)
main components of central nervous system (2)
- brain
2. spinal cord
main nerve types of peripheral nervous system (2)
- somatic nerves
- involved w voluntary movement
- > senses/movement - autonomic nerves
- involved w involuntary movement
- > sympathetic/parasympathetic systems
major cell types of the nervous system (2)
- neurons
- conduct electrical signals - glial cells
- structural & insulating support for neurons
neuron structure handout
check diagram
how do electrical signals pass through cells
membrane potential (video)
neuron signalling (role of glial cells)
- glial cells provide insulation for electrical impulses to pass through axon
- glial cell membrane has a lot of lipid molecules (called a myelin sheath when wrapped around an axon)
sensory neuron
aka, function, found where
aka afferent neurons
- carries signals from sensory receptors to the CNS for processing
- > photoreceptors (eyes)
- > chemoreceptors (nose)
- > thermoreceptors (skin)
- found in clusters of neurons - ganglia
what are ganglia
clusters of neurons
interneuron
aka, function
aka association neurons
- receives incoming signals from sensory neurons
- delivers outgoing signals to neurons responsible for responses
motor neuron
aka, connected to?
aka efferent neurons
- connected to tissues that respond according to what was detected
- > muscle contraction
- > gland secretion
do neurons regenerate
yes, peripheral system neurons will repair faster than central system neurons
action potential
animation (video)
- polarized membrane
- depolarization
- repolarization
polarized membrane
positive exterior, negative interior
- maintained by sodium-potassium pump
depolarization
negative exterior, positive interior
- voltage-dependent channels open to allow sodium ions to rush into cell
repolarization
positive exterior, negative interior
- voltage-dependent channels open to allow potassium ions to leave the cell
- restored by sodium-potassium pump
two states of the neurons (action potential)
- resting potential: -70mV
- required before a signal can be detected - action potential: +40mV
- change that occurs to transmit signal
action potential factors
- refractory period
- threshold
- axon diameter
- saltatory conduction
refractory period
time is needed to re-establish the resting potential after an action potential has been initiated
- no other action can be initiated, no matter how strong the signal
threshold level
different neurons have differing threshold levels before an action potential will proceed
sensitive neurons will have low threshold values
all-or-none response
neurons will or will not fire
saltatory conduction
Na+ and K+ exchange can only occur where the axons are exposed to the extracellular fluid (node of Ranvier)
- allows for faster signal conduction along the axon
