NEUROSCIENCE EXAM SET (B)
QUESTIONS WITH VERIFIED
ANSWERS
HEMOSTATIC SYSTEM use our behavior to keep things balanced - Answer--
negative feedback systems are the main homeostatic mechanisms. If desired set
point is devaited from, compensatory action begins
- "ill eat when imhungry, ill drink when im dry. if the moonshine done kill me, ill live till
i die"
HYPOVOLEMIC THIRST & OSMOTIC THIRST
- HYPOVOLEMIC THIRST
- OSMOTIC THIRST - Answer-- HYPOVOLEMIC THIRST: is stimulated by low
extracellular or intravascular volume:
- from blood loss, more commonly from sweating
- OSMOTIC THIRST: is stimulated by high extracellular solute concentration:
- happens every time you eat
- triggers by salt molecule that you eat
- salt hypertonic to the rest of the body
- shift of the water thats already in the body
HYPOVELEMIC THIRST
- BARORECEPTORS
- HYPOVOLEMIA - Answer-- triggered by LOSS OF WATER VOLUME:
concentration is not changed
- BARORECEPTORS: in blood vessels and heart detect the initial drop
- brain activated thirst and salt craving
- arteries constrict to raise Bp
- HYPOVOLEMIA: causes release of vasopressin (antidiuretic hormone):
- induces blood vessel constriction and so reduces blood flow to the bladder
- FYI: on DIABETES INSIPIDUS: vasopressin is not produced - kidneys send more
urine to the bladder, resulting in chronic thirst
ANGIOTENSIN CASCADE - Answer-- Angiotensin II and its mirroring effects
- if blood volume decreases, kidneys release renin, which triggers formation of
angiotensin II
- effects:
1. blood vessels constrict
2. cricumventricular organs trigger drinking
3. vasopressin is released
4. aldosterone is released
BRAIN CONTROLS OF DRINKING - Answer-- circulating angiotensin II acts in the
SUBFORNICAL ORGAN to signal other brain sites to initiate drinking:
,- connected to the motor system, change of though to motivate you to drink
something to satisfy your thirst
SAMPLE QUESTION
- a fall in blood andiotensis II level....
a. makes one feel thirsty
b. raises blood pressure
c. occurs after eating salt
d. none of the above - Answer-the answer is D. none of the above because
a. if there is a fall of angiotensisn II then that means you are no longer thirsty
b. raises blood pressure - angiotensin II does this
c. not relative to this process
OSMOTIC THIRST
- OSMOSENSORY NEURONS
- OVLT NEURONS - Answer-- OSMOSENSORY NEURONS in anterior
hypothalamus (OVLT) respond to rise in blood osmotic pressure
- powered by too many osmols in the blood stream:
- osmols are just salt molecules in the brain
- we need receptors in the service of the neuron that says oh we have shrunk
- their cell membranes shrink, opening mechanical gated Na+ channels
- osmosensory neurons:
- greater concentration of solutes outside the cell than outside
- water flows out of the cell, equalizing the solute concentration and shrinking the cell
- OVLT NEURONS: respond to increased osmotic pressure by causing the pituitary
to release antidiuretic hormone (like vasopressin)
HUNGER
DIETS, WHY THEY DON'T WORK - Answer-- energy expenditure is adjusted in
response to nutrition
- at start of a diet, the basal metabolic rate fails - to prevent using weight
- restricted food intake does promote longevity, up to 40% in rats - in people
probably not
OBESITY AND REDUCED METABOLISM
- BMR - Answer-- your body defends itself when you go on a diet:
- when you restrict food it changes your BMR
- BASAL MEATBOLIC RATE (BMR):
- energy required to fuel the brain/ body and maintain temperature
- 75% of energy expenditure in average sedentary student
- women on a diet, the 1/3 who failed to lose weight had LOW BMRs
- heredity accounts for 40% of a person's BMR. BUT ACTIVITY CAN INCREASE IT
ENERGY STORAGE/ UTILIZATION
- GLUCOSE
,- GLYCOGEN
- GLYCOGENESIS
- LIPIDS - Answer-- GLUCOSE: is the principal fuel for energy
- GLYCOGEN: is glucose for short term in liver:
- glucose stored
- GLYCOGENESIS: converting glucose to glycogen, using pancreas hormone insulin
- LIPIDS: for long term storage, are FAT TISSUE
REGULATION OF FOOD INTAKE - Answer-- brain integrates insulin and glucose
levels with other signals to decide when to start/ stop eating
- external factors:
- emotions, food characteristics, lifestyle behaviors, environmental cues
- things that can either increase or decrease your desire to eat
- ex: if you're stressed you may have no appetite or you may eat more comfort foods
- central signals
- stimulants (NPY) and inhibits (delta- MSH)
- peripheral signals:
- glucose, insulin, ghrelin, leptin, cortisol)
- things from your gut
- as glucose rise you shouldn't be hungry, when they fall they make you hungry
again
- insulin job is to take glucose and put it into the blood stream
LEPTIN - Answer-- fat cells produce leptin and secrete it into the blood stream
- defects in leptin production or sensitivity give a FALSE LOW REPORT OF BODY
FAT, causing animals to overeat
- obese people are leptin resistant
- over nutrition INFLAMES the hypothalamus - obesity, diabetes and heart disease
1.) adipose tissue, weight loss, leptin level falls:
- Hypothalamus: food intake up, temperature down, energy expenditure down,
reproductive function down, parasympathetic activity up
2. adipose tissue, weight gain, leptin level rises:
- Hypothalamus: food intake down, energy expenditure up, sympathetic activity up
GHRELIN
- case: Prader will syndrome - Answer-- released by stomach endocrine cells -
appetite stimulant
- rises during fasting, drops after eating
- some obese people have elevated ghrelin. levels (not many just some)
- CASE: for kate kane, food is on her mind "all the time". Kate, 26, have Prader will
syndrome, a genetic disease that causes a sense of never being full or satisfied.
Kane feels so hungry that she even eats out of the garbage to get to her food.
Parents had to lock their refrigerator doos. She could eat until she died basically
, - why? the brain always says that she is super hungry
SAMPLE QUESTION
- blood signals that stimulate appetite include
- rising ghrelin
- rising cortisol
- falling insulin
- all of the above - Answer-all of the above
WHY DO WE HAVE SEX? - Answer-- reproduction (more of us)
- DNA shuffling (but not exactly us)
- its fun (uniquely human)
- sex is like hunger and thirst:
- it is not a homeostatic tissue need
- individuals don't require sex for survival (species do)
SEX AND ESTROGEN - Answer-- estrogen rise before OVULATION promote
nonhuman sexual behavior
- if a female is SEXUALLY RECEPTIVE she is in estrus (dogs) // estrus is the period
during which female animals are sexually receptive
- women don't have estrus:
- but are more likely to initiate sex as ovulation
- monthly cycle is a cycle of hormones
- androgens are necessary for male copulation
- this does apply to human males
- testosterone is linked to aggression and sex
SEXUAL RESPONSE CURVES - Answer-- men vs. women: 4 phases:
1. excitement phase (arousal)
2. in plateau, arousal levels off
3. orgasm
4. resolution, as arousal fails and body returns to normal
- MALE ORGASM: predictable, one shot
- WOMEN'S ORGASM: know your partner's curve
PET IMAGING OF MALE ORGASM - Answer-- oxytocin releases at ejaculation; and
maybe promoting bonding?
- primary activation was in VENTRAL TEGMENTAL AREA:
- activation of dopamine
PET IMAGING OF FEMALE ORGASM - Answer-- activation of the deep cerebellar
nuceli
- inhibition of orbitofrontal cortex
SEX: IMPORTANT BRAIN AREAS FOR BOTH SEXES - Answer-- MEDIAL
AMYGDALA: (MeA,: in the temporal lobe)
- involved in sex, smell, aggression and emotions
QUESTIONS WITH VERIFIED
ANSWERS
HEMOSTATIC SYSTEM use our behavior to keep things balanced - Answer--
negative feedback systems are the main homeostatic mechanisms. If desired set
point is devaited from, compensatory action begins
- "ill eat when imhungry, ill drink when im dry. if the moonshine done kill me, ill live till
i die"
HYPOVOLEMIC THIRST & OSMOTIC THIRST
- HYPOVOLEMIC THIRST
- OSMOTIC THIRST - Answer-- HYPOVOLEMIC THIRST: is stimulated by low
extracellular or intravascular volume:
- from blood loss, more commonly from sweating
- OSMOTIC THIRST: is stimulated by high extracellular solute concentration:
- happens every time you eat
- triggers by salt molecule that you eat
- salt hypertonic to the rest of the body
- shift of the water thats already in the body
HYPOVELEMIC THIRST
- BARORECEPTORS
- HYPOVOLEMIA - Answer-- triggered by LOSS OF WATER VOLUME:
concentration is not changed
- BARORECEPTORS: in blood vessels and heart detect the initial drop
- brain activated thirst and salt craving
- arteries constrict to raise Bp
- HYPOVOLEMIA: causes release of vasopressin (antidiuretic hormone):
- induces blood vessel constriction and so reduces blood flow to the bladder
- FYI: on DIABETES INSIPIDUS: vasopressin is not produced - kidneys send more
urine to the bladder, resulting in chronic thirst
ANGIOTENSIN CASCADE - Answer-- Angiotensin II and its mirroring effects
- if blood volume decreases, kidneys release renin, which triggers formation of
angiotensin II
- effects:
1. blood vessels constrict
2. cricumventricular organs trigger drinking
3. vasopressin is released
4. aldosterone is released
BRAIN CONTROLS OF DRINKING - Answer-- circulating angiotensin II acts in the
SUBFORNICAL ORGAN to signal other brain sites to initiate drinking:
,- connected to the motor system, change of though to motivate you to drink
something to satisfy your thirst
SAMPLE QUESTION
- a fall in blood andiotensis II level....
a. makes one feel thirsty
b. raises blood pressure
c. occurs after eating salt
d. none of the above - Answer-the answer is D. none of the above because
a. if there is a fall of angiotensisn II then that means you are no longer thirsty
b. raises blood pressure - angiotensin II does this
c. not relative to this process
OSMOTIC THIRST
- OSMOSENSORY NEURONS
- OVLT NEURONS - Answer-- OSMOSENSORY NEURONS in anterior
hypothalamus (OVLT) respond to rise in blood osmotic pressure
- powered by too many osmols in the blood stream:
- osmols are just salt molecules in the brain
- we need receptors in the service of the neuron that says oh we have shrunk
- their cell membranes shrink, opening mechanical gated Na+ channels
- osmosensory neurons:
- greater concentration of solutes outside the cell than outside
- water flows out of the cell, equalizing the solute concentration and shrinking the cell
- OVLT NEURONS: respond to increased osmotic pressure by causing the pituitary
to release antidiuretic hormone (like vasopressin)
HUNGER
DIETS, WHY THEY DON'T WORK - Answer-- energy expenditure is adjusted in
response to nutrition
- at start of a diet, the basal metabolic rate fails - to prevent using weight
- restricted food intake does promote longevity, up to 40% in rats - in people
probably not
OBESITY AND REDUCED METABOLISM
- BMR - Answer-- your body defends itself when you go on a diet:
- when you restrict food it changes your BMR
- BASAL MEATBOLIC RATE (BMR):
- energy required to fuel the brain/ body and maintain temperature
- 75% of energy expenditure in average sedentary student
- women on a diet, the 1/3 who failed to lose weight had LOW BMRs
- heredity accounts for 40% of a person's BMR. BUT ACTIVITY CAN INCREASE IT
ENERGY STORAGE/ UTILIZATION
- GLUCOSE
,- GLYCOGEN
- GLYCOGENESIS
- LIPIDS - Answer-- GLUCOSE: is the principal fuel for energy
- GLYCOGEN: is glucose for short term in liver:
- glucose stored
- GLYCOGENESIS: converting glucose to glycogen, using pancreas hormone insulin
- LIPIDS: for long term storage, are FAT TISSUE
REGULATION OF FOOD INTAKE - Answer-- brain integrates insulin and glucose
levels with other signals to decide when to start/ stop eating
- external factors:
- emotions, food characteristics, lifestyle behaviors, environmental cues
- things that can either increase or decrease your desire to eat
- ex: if you're stressed you may have no appetite or you may eat more comfort foods
- central signals
- stimulants (NPY) and inhibits (delta- MSH)
- peripheral signals:
- glucose, insulin, ghrelin, leptin, cortisol)
- things from your gut
- as glucose rise you shouldn't be hungry, when they fall they make you hungry
again
- insulin job is to take glucose and put it into the blood stream
LEPTIN - Answer-- fat cells produce leptin and secrete it into the blood stream
- defects in leptin production or sensitivity give a FALSE LOW REPORT OF BODY
FAT, causing animals to overeat
- obese people are leptin resistant
- over nutrition INFLAMES the hypothalamus - obesity, diabetes and heart disease
1.) adipose tissue, weight loss, leptin level falls:
- Hypothalamus: food intake up, temperature down, energy expenditure down,
reproductive function down, parasympathetic activity up
2. adipose tissue, weight gain, leptin level rises:
- Hypothalamus: food intake down, energy expenditure up, sympathetic activity up
GHRELIN
- case: Prader will syndrome - Answer-- released by stomach endocrine cells -
appetite stimulant
- rises during fasting, drops after eating
- some obese people have elevated ghrelin. levels (not many just some)
- CASE: for kate kane, food is on her mind "all the time". Kate, 26, have Prader will
syndrome, a genetic disease that causes a sense of never being full or satisfied.
Kane feels so hungry that she even eats out of the garbage to get to her food.
Parents had to lock their refrigerator doos. She could eat until she died basically
, - why? the brain always says that she is super hungry
SAMPLE QUESTION
- blood signals that stimulate appetite include
- rising ghrelin
- rising cortisol
- falling insulin
- all of the above - Answer-all of the above
WHY DO WE HAVE SEX? - Answer-- reproduction (more of us)
- DNA shuffling (but not exactly us)
- its fun (uniquely human)
- sex is like hunger and thirst:
- it is not a homeostatic tissue need
- individuals don't require sex for survival (species do)
SEX AND ESTROGEN - Answer-- estrogen rise before OVULATION promote
nonhuman sexual behavior
- if a female is SEXUALLY RECEPTIVE she is in estrus (dogs) // estrus is the period
during which female animals are sexually receptive
- women don't have estrus:
- but are more likely to initiate sex as ovulation
- monthly cycle is a cycle of hormones
- androgens are necessary for male copulation
- this does apply to human males
- testosterone is linked to aggression and sex
SEXUAL RESPONSE CURVES - Answer-- men vs. women: 4 phases:
1. excitement phase (arousal)
2. in plateau, arousal levels off
3. orgasm
4. resolution, as arousal fails and body returns to normal
- MALE ORGASM: predictable, one shot
- WOMEN'S ORGASM: know your partner's curve
PET IMAGING OF MALE ORGASM - Answer-- oxytocin releases at ejaculation; and
maybe promoting bonding?
- primary activation was in VENTRAL TEGMENTAL AREA:
- activation of dopamine
PET IMAGING OF FEMALE ORGASM - Answer-- activation of the deep cerebellar
nuceli
- inhibition of orbitofrontal cortex
SEX: IMPORTANT BRAIN AREAS FOR BOTH SEXES - Answer-- MEDIAL
AMYGDALA: (MeA,: in the temporal lobe)
- involved in sex, smell, aggression and emotions
