BIOL 182 Quiz 5

reproduction hormones order

brain -->(GnRH)-->anterior pituitary-->(FSH, LH)-->gonad

What is LH (luteinizing hormone)?

Produced in pituitary gland, stimulates release of egg at the middle of the menstrual cycle

steroid production

What is FSH (Follicle stimulating hormone)?

Produced in pituitary gland, causes egg to mature in ovaries, stimulates the production of estrogen in ovaries maturity of gonads

seminiferous tubules

site of sperm production, two types

Sertoli cells

target of FSH

Leydig cells

target of LH

example of negative feedback loop

testosterone feeds back to reduce production of LH

what would happen if you blocked GnRH receptors?

decreased testosterone ie contraceptive in deer

what does FSH do in females?

stimulates development of ovarian follicles

what are the three steroid sex hormones?

androgen, estrogen, progesterone

What does GnRH stand for?

gonadotropin releasing hormone

Key difference between FSH and LH

FSH stimulates follicle to grow, LH triggers ovulation

ovarian cycle

follicular phase, ovulation, luteal phase

ovum is surrounded by what

follicle cells

what do follicular cells form?

corpus luteum which eventually disintegrates

what does FSH stand for?

follicle-stimulating hormone

What does LH stand for?

luteinizing hormone

follicular phase of ovarian cycle

period of follicle growth (days 1-14), estradiol concentration rises the most, levels of FSH and LH rise

Sex steroid cycle

increase in estradiol, follicle maturation

Progesterone

promotes uterine lining growth

what does the abortion pill do?

blocks progesterone receptors, no thickening of the uterine lining for baby

menstrual cycle

lining increases and is shed if no pregnancy

What does birth control do?

blocks ovulation, release of GnRH and LH

what are misconceptions about cortisol?

causes bad sleep, makes you fat

benefits of cortisol

fight or flight response

detriments of cortisol

high blood pressure/sugar, suppress immune system

nervous system involves which body parts

brain and spinal cord

parasympathetic nervous system

rest and digest; activates digestion

sympathetic nervous system

fight or flight; inhibits digestion

Stress and ______________ gland

adrenal

adrenal medulla (endocrine gland) and epinephrine

What does the adrenal medulla do?

increases blood glucose, breathing rate, redirects blood to muscles

adrenal cortex and cortisol

ATCH produces cortisol, comes from anterior pituitary hormones

what is ATCH?

tropic hormone

what are the functions?

mobilize internal fuel (breakdown fats and proteins in muscle and liver), regulate sleep-wake cycles of energy, increase blood pressure

what happens to long term elevation of cortisol?

muscle wasting, reproductive inhibition, immunosuppression

Order of cortisol release

hypothalamus--> CRF--> anterior pituitary--> ATCH--> adrenal cortex--> cortisol

timescale of sympathetic

milliseconds

timescale of epinephrine

seconds to minutes

timescale of cortisol

longer time frame

stress responses involve what

BOTH nervous and endocrine systems

3 stages of nervous system processing

sensory input, integration, motor output

sensory input

surveys environment

Integration

To process and interpret sensory input and decide if action is needed

motor output

response to stimuli by activating effector organs

two hallmark features of nervous system

highly interconnected, electrically active

typical neuron connects with

thousands of other neurons

Synapse

A junction where information is transmitted from one neuron to the next.

axon

transmits information to other neurons, muscles, or glands

where do synapse and axon connect?

postsynaptic cell

what charge is a neuron at rest?

negative

sensory neurons

transmit info about external stimuli

interneurons

form local circuits; responsible for integration

Motorneurons

signals to muscle cells, cause them to contract

axons of neurons form

nerves

all neurons happen

within milliseconds

What is battery?

resting potential

what is the signal?

action potential form

What is transmission?

action potential propagate

two ions

Na+ and K

two movements

in and out of neuron

two gradients

chemical and electrical

sodium electrical gradient

When its more (-) inside, Na wants to move in

potassium electrical gradient

moves into cell

sodium chemical gradient

more sodium outside of the cell than inside, wants to move in

potassium chemical gradient

More potassium inside the cell than outside, wants to move out (leaks slowly)

outside of cell is

positive

inside of cell is

negative

what would happen if drug on neuron opened more Na+ channels?

Na+ enters neuron, neuron becomes more positive

sodium-potassium pump

for every 3 Na+ that is pumped out, 2 K go in, more pos ions leaving so the cell is neg, sodium builds up on the outside

what happens when enough Na+ channels are opened?

reach threshold and formation of action potential, AP: opening/closing of ion channels

what happens when channel opens?

rapid flow of ions

Hyperpolarization

inside of membrane becomes more negative

Depolarization

membrane less negative than the outside, opens both K and Na+ channels (happens first; initiates AP)

4 steps of action potential

resting state, depolarization, threshold, falling phase

rest

all channels closed

Depolarization (AP step)

few channels open, cell becomes positive, pos feedback loop open more channels

threshold

cell becomes really pos really fast, electrical K gradient switches

falling phase

sodium channels close and potassium channels open

what happens when cell is pos?

electrical gradient switches and potassium leaves so cell goes back to negative

refractory period

a period of inactivity after a neuron has fired

Schwann cells

form membrane around axon

myelin sheath

acts like insulation which speeds up transmission, produced by glia, mostly lipid cells which are poor conductors

touch controlled by

myelinated neurons; happens fast

pain controlled by

non myelinated neurons; happens slower

Epilepsy

mutations affect NA+ channels causing it to fire rapidly

Overall scheme in both sexes

brain produces GnRH>>secretes hormones in anterior pituitary (FSH, LH)>>they go toward the gonad (gonadotropins)

Characteristics in male hormone production

-testis has seminiferous tubules (houses sertoli+leydig cells)

-sertoli cells make nutrients for maturing sperm (target of FSH), and produce inhibin and spermatogenesis

-leydig cell is the target of LH, and produce testosterone (secrete a little oxytocin, renin, angiotensin, growth hormones)

Characteristics in female hormone production

anterior pituitary promotes estrogen production, FSH acts on gamete formation, maturation of oocyte, steroid hormones from ovary: estradiol and progesterone, protein hormones from pituitary: LH and FSH

What is the ovarian cycle and what are the steps of it?

cyclic reoccurrence of follicular, ovulation, luteal phase; hypothalamus releases GnRH>>stimulates anterior pituitary to secrete some FSH, LH (peaks during:)>>follicular phase, estradiol concentration increases>>ovulation>>FSH and LH decrease during luteal phase because of follicle and wall rupture that releases secondary egg>>LH makes remaining follicular tissue form corpus luteum which secretes progesterone and estradiol>>exerts negative feedback on hyp.+ant. pit.>>reduces LH and FSH secretion and prevents maturation of egg>>if there's no pregnancy, corpus luteum degenerates

What is the corpus luteum?

the corpus luteum develops from a ruptured follicle in the ovary and secretes estrogen and progesterone

Steps of the gonadotropin cycle in women

FSH and LH stimulate follicle growth>>ovulation occurs mid-cycle>>LH surge triggers ovulation and formation of corpus luteum

Steps of the sex steroid cycle in women

increased production of estradiol (follicle matures)>>causing peak (LH surge)>>progesterone promotes thickening of uterine lining

What does estradiol do?

Assists follicle growth (with FSH); bone and muscle growth; causes maturation and release of egg; thickens uterus to allow plantation of a fertilized egg

What is progesterone important for?

gestation (pregnancy) by preparing uterus lining for a fertilized egg to grow

Synapses can be _____ or ______

electrical or chemical

chemical synapse

a type of synapse at which a chemical (a neurotransmitter) is released from the axon of a neuron into the synaptic cleft, where it binds to receptors on the next structure (either another neuron or an organ)

electrical synapse

a type of synapse in which the cells are connected by gap junctions, allowing ions (and therefore the action potential) to spread easily from cell to cell, rapid, unchanging behaviors

the trigger

what initiates AP? inputs and sensations

the connection

how do AP affect other neurons; synaptic transmission

presynaptic neuron

neuron that sends the signal