Brain and Behavior Exam 3

homeostasis

process that keeps the body variables in a fixed range/set point

negative feedback

actions that lower inconsistencies in the set point

allostasis

body anticipates needs and avoids mistakes

basal metabolism

energy used to maintain body temperature at rest 

brown adipose cells

metabolizes and produces heat by burning fuel like muscles and releasing it like muscle contractions

ectothermic

dependent on external heating sources

endothermic

mechanisms used to keep core at a constant temperature

evaporation

used to cool the body in a hot environment

generating heat

mechanisms that increase body heat in a cold environment

shivering

used to maintain body temperature 

reproductive cell environment

cool

hypothalamus physiological effect

causes shivering, sweating, blood flow change

preoptic area/anterior hypothalamus (POA/AH)

sends signals to hindbrain’s rapne nucles (controls physiological reactions); controls body temperature

infections

make immune system release prostaglandins and histamines; POA/AH raises set point for body temp

fever

shivering/sweating when body temp deviates from new level; can kill bacteria and makes immune system work harder

vasopressin

constricts blood vessels (raises blood pressure) to compensate for decrease in blood volume; OVLT + SFO cells tells pituitary gland to release it

antidiuretic hormone (ADH)

lets kidneys reabsorb water from urine (more concentrated)

osmotic thirst

caused by eating salty foods, drive to drink water to restorenormal state

hypovolemic thirst

cause by losing fluids through bleeding/sweating

ostomic pressure

water flows from low to high concentration

sodium accumulation

happens when you eat something salty; high solutes outside membrane

OLVT + SFO

check for ostomic pressure and sodium content in blood; sense water loss and increase ostomic pressure

angiotensin II

constricts blood vessels to help make up drop in blood pressure; detects blood pressure and triggers thirst (LOW BLOOD VOLUME)

angiotensin

is released by neuromodulator and responds to hypovolemic thirst - and restores lost salts and water

sodium-specific hunger

need to consume salty tastes thanks to sodium deficiency

aldosterone

released by body’s sodium reserve is low and helps retain salt (LOW SODIUM)

lactase

intestinal enzyme, needed for metabolizing lactose 

stomach distension

main signal to end a meal

sham feeding

animals eat and swallow continually without being satiated

vagus nerve (cranial nerve)

conveys info to the hypothalamus about stretching the stomach walls

duodenum

area where nutrients are absorbed; nerves here inform the brain about distension and type and amount of nutrient 

Cholecystokinin

released by distension, produces satiety by constricting sphincter muscle so stomach holds contents and fills up AND enabling the vagus nerve to send signals to hypothalamus to send a neurotransmitter that can cross the blood-brain barrier

insulin

enables glucose to enter the cells and prevents blood glucose levels from rising too sharply; is released by pancreas before/after meals

after a meal

blood glucose drops, insulin drops, and glucose enters slowly so hunger increases

glucagon

stimulates the liver to convert some glycogen into glucose; pancreas enables release  

high insulin

increased weight

diabetes

disorder of glucose absorption

type 1 diabetes

autoimmune attack reduces/eliminates pancreas’s ability to produce insulin

type 2 diabetes

pancreas produces insulin, but cells don’t respond to it

untreated diabetes

blood glucose level rises, but not much glucose enters the cells 

leptin

signals brain about fat reserves

low fat reserves

low leptin; you eat more and are less active

axons functions

affects taste sensations and salivation response to taste (cortical cells increase this) + hormone, insulin, digestive secretion

sexual selection

genes that increase an individual’s mating probability /offspring also spreads in the population

turner syndrome XO

y chromosome never got copied; missing or part of second X chromosome or two full X chromosome

Klinefelter syndrome XXY/XXYY/XXXY

extra copy of chromosome; masculine features + self-identification but infertile

mullerian ducts

precursors to female internal structures

wolffian ducts

precursors to male internal structures

SRY gene

causes undifferentiated gonads to develop into testes

androgens

testes increase growth of testes and produces more of these

vasdeferens

duct from testis into the penis

Mullerian-inhibiting hormone (MIH)

mullerian ducts degenerate into penis and scrotum, into vagina and uterus; produced by testes

male testes

androgens increase and estrogens decrease

female ovaries

estrogens increase and androgens decrease

estrogen

helps in memory and cognition; produced by adrenal glands 

steroid hormones

androgens (testosterone) and estrogens (estradiol)

progesterone

prepared the uterus for implantation of fertilized ovum and pregnancy maintenance

steroids

bind to receptors, enter the cells to activate specific proteins and bind to chromosomes to activate/inactivate specific genes

organizing effects in sex hormones

long-lasting (puberty)

activating effects in sex hormones

temporary, continue while hormone’s present (hormone levels affect sex drive)

high testosterone

develops male pattern

low testosterone

develops female pattern

high dihydrotestosterone

penis and scrotum development

low dihydrotestosterone

clitoris and labia development

estradiol in prostate gland

produces fluid that protects sperm cells when ejaculated (during sex)

female hypothalamus

cycle patterns of hormone release (menstrual cycle)

male hypothalamus

hormones released more steadily

alpha-fetoprotein

prevents estradiol from entering cells; female brain not exposed to estradiol thanks to this

girls with high testosterone

play more with toy trains

oxytocin

stimulates uterus contraction during delivery of babies and stimulates mammary gland to release milk; helps reduce anxiety and calms after orgasm

male sexual arousal

androgens are essential

D1 and D5 receptors

increase sexual arousal

D2 receptors 

high dopamine concentration, causes orgasm 

after orgasm

serotonin increases and testosterone goes down

serotonin

decreases sexual activity and blocks dopamine

impotence

inability to have an erection, poor blood circulation

menstrual cycle

produced by hypothalamus, pituitary glands, and ovaries; period of change in hormones and fertility in 28 day cycle

follicle stimulating hormone (FSH)

stimulates follicle growth in the ovary; stimulates nurture ovum and creates estradiol and estrogen

@ middle of menstruation cycle

follicle gains more receptors to FSH and produces lots of estradiol- effects on follicle increase

lutenizing hormone (LH)

released from anterior pituitary; leads to release of ovum from follicle

increased FSH and release of LH

increased estradiol

FSH + LH

follicle releases ovum from uterus (most fertile time)

corpus luteum

remainder of follicle; releases hormone progesterone 

progesterone

prepares the uterus for fertilized ovum implantation and blocks further release of LH

pregnancy

FSH isn’t needed; estradiol and progesterone increases and serotonin 3 (s)

menstruation starts

lining of uterus is cast off and estradiol and progesterone decreases

pre-ovulatory 

rise in attention seeking behavior, peak fertility at midcycle

birth control pills

prevent pregnancy by changing feedback cycle in the ovaries and pituitary

combination pill

prevents FSH and LH from releasing ovum and prevents ovum from implanting in the uterus; thickens cervix mucus (sperm can’t reach ovum)

prolactin

stimulates milk production up after birth

arcuate nucleus (hypothalamus)

set of neurons for hunger signals; get their input from insulin and leptin (and amygdala)

NPY/AGRP

hunger neurons

POM/CART

satiety neurons

ghrelin

triggers stomach contractions when starving and increases appetite in hypothalamus 

hunger cells

inhibit the paraventricular nucleus which inhibits the lateral hypothalamus → excites the lateral hypothalamus so there’s INCREASED eating

satiety cells

excite the paraventricular nucleus which releases melanocortin and glutamate 

melanocortin

helps limit food intake

orexin

increases activity (food searching) and promotes wakefulness

lateral hypothalamus 

controls insulin secretion, changes in taste responsiveness, and facilitates feeding; increased DRIVE TO EAT t if stimulated

damage to lateral hypothalamus

refusal of food and water; kills neurons and interrupts axons containing dopamine