excitable cell + endocrine

Question 1

simple diffusion vs channel-mediated diffusion vs facilliated diffusion vs active transport

Answer 1

simple diffusion: directly cross the plasma membrane w/o use of membrane protein
c.m diffusion: w/ protein **channels **
faciliated diffusion: undergoes a conformational change w/ protein carrier; mole binds & shift to other side
active transport: require **ATP, **only 1 to go against the c. grad

Question 2

endocytosis vs exocytosis

Answer 2

endocytosis: absorb molec by forming a pocket w/ cell membrane; gets pinched off as a vesicle
exocytosis: vesicle fuse to plasma membrane, release content

Question 3

describe the water mvmnt in isotonic vs hypertonic vs hypotonic ? why

Answer 3

isotonic: no net mvmnt of water ‘ oSM same as body fluid
hypertonic: water leaves the cell ‘ lower than body fluid
hyPOtonic: water enters the cell ‘ higher oSM

Question 4

list 3 types of gates

Answer 4

1. mechanically gated i.c: requries mechanical manipulation
2. chemically gated i.c: w/ chmical binding, open
3. voltage gated i.c: w/ voltage change, open

Question 5

depol: cell becomes more ____ than RMP (when ___/__ opens)
repol: cell returns to _____
hyperpol: cell becomes more ____ than RMP (when __/___ enters)
threshold: min ____ o trigger ____

Answer 5

(+) when Na+ / Ca++
RMP
(-) / when K+ leaves / Cl+ enters
voltage / AP

Question 6

looses strength over time and travels a short distance

Answer 6

graded potential (e.g in eye)

Question 7

when Na+ VG channels open, it travels from ____ (high/low) to ____(high/low) concentration gradient

=> electrical potential accumulates more (+/-) change

Answer 7

high to low

more

Question 8

how to trigger an AP in graded potential?

Answer 8

1. stimulus creates depol: Na+ enters via mech/chem channels
2. as it travels down to the axon hillock., K+ leaks out
3. graded potential hits threshold => triggers AP
4. signal sent to the brain

Question 9

describe the action potential

Answer 9

1. due to graded potential, depol occurs
   => Na+ VG channels open
2. since they’re quick to close, Na+ stops
3. since K + VG channesl slower to open, repol occurs (back to RMP)
4. since they’re** slower to close**, hyperpol occurs

Question 10

how AP propagates down an axon

Answer 10

1. graded potential occurs
   Na+ VG channels open => depol occurs
2. these Na+ is attracted to next section, still @ RMP (+ to -)
   => AP fires in next section
3. meanwhile repol & hyperpol occurs in the 1st

Question 11

name a myelin-related disease

Answer 11

multiple sclerosis: myelin damaged adn starts to dissapear
=> AP can’t properly propagate down an axon

Question 12

describe the (-) fdbk loop at thyroid gland

Answer 12

hypothalamus releases Thyrotropin R.H (TRH)
=> stimulates the release of thyroid stimulating hmn (TSH)
make T3 / T4 at the thyroid gland

if high lvl of T3/ T4, create a (-) fdbk loop
supresses TRH & TSH
lwoer T3 & T4

Question 13

compare hyperthyroidism vs hypothyroidism

Question 14

describe the (-) fdbk loop of corticol

Question 15

how would a doctor diagnos a Cushing’s disease?

Question 16

what happens in a chemical synapse

hint think of NMJ for skeletal muscle

Answer 16

1. AP arrives @ axon terminal, depol area
   2.** Ca2+ VG **channels open
2. vesicle fuse to the plasma membrane, release content to the synpatic cleft
3. binds to receptor on post-snypatic membrane
4. LIGAND gated channels open
5. GRADED POTENTIAL occurs in post-synaptic neuron

Question 17

if depol__ occurs in the post-synpatic neuron, this is called ______ (EPSP)

if _____ occurs in the post-synpatic neuron, this is called ______ (IPSP)

Answer 17

excitatory post-synpatic potential
hyperpol / inhibitory post-synpatic potential

Question 18

how hmn travel in ant pituitary

Answer 18

neurons from hyothalamus travels down the hypothalamus- hyposeal portal system towards ant. p
bounds to membrane bound receptor there
triggers premade peptide
towards target tissue

Question 19

why is A FLAT PIG relevant?

Answer 19

adreno-corticotropic hmn (ACTH) acts on corticotropin r.h towards adrenal glands
Thyroid Stimulating hmn acts on Thyrotropin R.H for thyroid glands
prolactin acts on Prolactin R.H =? breast tissue
Growth Hmn acts on Growth Hmn R.H => various

Question 20

hyperthyroidism vs hypothyroidism

Answer 20

hyper– vs hypo–
increase in T3 & T4 vs decrease
high basal metabolic rate
sensitive to warm room temp vs senstive to room temp
increased heart rate + hyperactive vs snow reflex, lethargy, apathy

Question 21

describe the (-) fdbk loop of in zonna fasciculata

Answer 21

hypothalamus releases corticotropin R.H (CRH)
=> stimulates the release of adrenocorticotropic hmn (ACTH)

releases cortisol in adrenal glands

creates a (-) fdbk loop
=> supresses CRH, ACTH
=> lowers cortisol lvl

Question 22

composition of T3 & T4

Answer 22

triiodothyronine (T3) & thyrosine (T4)

tyrosine precursor + iodine = T3 & R4

Question 23

T/F: ADH is made in posterior pituitary

Answer 23

F ‘ posterior pituitary doens make hmn

ADH & oxytocin travels down from hypothalamus to pos. p

Question 24

describe a peptide/protein hmn

Answer 24

in in -in or -hmn
w/ membrane bound receptor, dissolve in blood and hydrophilic
precursor: amino acid

Question 25

describe a steroid hmn

Answer 25

ends in -ol or -one
w/ intracellular receptor, transported in bnlood and bound to protein
lipophilic
precursor: cholesterol

Question 26

distinct amino hmn: hydrophilic and hydrophobic

Answer 26

(+): precursor both tyrosine

hydrophobic: w/ intracellular receptor, transported in blood and bound to protein; lipophilic
hydrophilic: w/ membrane bound receptor, disoolved in bnlood and hydrophilic

Question 27

T/F: propagation is faster in myelinated neurons (w/ saltatory conduction0 than unmyelinated one (continuous conduction)

Answer 27

T