CH.24 Part 2 Flashcards
What type of feedback system regulates the secretion of thyroid hormone?
a) Positive feedback
b) Negative feedback
c) Neutral feedback
d) Amplifying feedback
b) Negative feedback. The regulation of thyroid hormone secretion operates on a classical negative feedback system, where rising thyroid hormone levels inhibit further secretion
What initially stimulates the production of thyroid hormone?
a) Thyroxine (T4)
b) Triiodothyronine (T3)
c) Thyroid stimulating hormone (TSH)
d) Thyrotropin releasing hormone (TRH)
c) Thyroid stimulating hormone (TSH). TSH, secreted by the anterior pituitary gland, initially stimulates the production of thyroid hormone.
How does thyroid hormone feedback inhibit further secretion?
a) By inhibiting the release of thyroxine (T4)
b) By increasing TSH secretion
c) By inhibiting TSH and TRH secretion
d) By promoting TRH synthesis
c) By inhibiting TSH and TRH secretion. Thyroid hormone feedback inhibits further secretion by inhibiting both TSH secretion by the anterior pituitary and TRH secretion by the hypothalamus.
Under what conditions may the inhibitory feedback at the level of the hypothalamus be overridden?
a) During starvation
b) During dehydration
c) During pregnancy and prolonged cold exposure
d) During exercise
c) During pregnancy and prolonged cold exposure. Some conditions, such as pregnancy and prolonged cold exposure, may override the inhibitory feedback at the level of the hypothalamus, leading to increased TRH secretion and subsequent elevation of thyroid hormone levels to increase metabolism and heat production.
Which of the following organs is not affected by thyroid hormone (TH)?
a) Spleen
b) Liver
c) Thyroid gland
d) Uterus
c) Thyroid gland.
d) Uterus
affects essentially every cell of the body except the thyroid gland itself, along with the adult brain, spleen, testes, and uterus.
What is one of the major functions of thyroid hormone?
a) Regulating blood sugar levels
b) Stimulating insulin production
c) Maintaining blood pressure
d) Regulating basal metabolic rate/body heat production
d) Regulating basal metabolic rate/body heat production. Thyroid hormone plays a major role in regulating the basal metabolic rate and body heat production, known as the calorigenic effect.
How does thyroid hormone contribute to maintaining blood pressure?
a) By regulating blood sugar levels
b) By stimulating insulin production
c) By regulating adrenergic receptor number
d) By promoting cholesterol synthesis
c) By regulating adrenergic receptor number
In addition to skeletal and nervous system development, what else does thyroid hormone regulate?
a) Blood clotting
b) Immune response
c) Digestion
d) Reproduction
d) Reproduction. Thyroid hormone plays a role in regulating tissue growth and development, including skeletal and nervous system development, maturation, and reproduction.
What is TMR
total kcals spent
food ingestion impact on TMR (FIT and fasting)
food-induced thermogenesis: energy needed to digest food
- higher in protein because of activation in liver
fasting/low intake: decrease in metabolic rate & slower break down of food.
how high can heat production by skeletal muscle during vigorous exercise be compared to the rest of the body.
a)10-20x
b)20-40x
c) 30-40x
c) 30-40x
does body temp change throughout the day? by how much
yes
1 degree
is body temo higher or lower in the mornings
lower
~50% of body heat loss (therefore body surface area
is a major determinant of BMR)
a)radiation
b)conduction
c)convection
d)evaporation
a)radiation
loss of heat by infrared waves
produce insensible water loss and insensible heat loss
10% of basal heat production
a)radiation
b)conduction
c)convection
d)evaporation
d)evaporation
enhanced by any process which moves air more rapidly across the body surface (wind or fan)
a)radiation
b)conduction
c)convection
d)evaporation
c)convection
direct physical contact with one another (eg. heat to body from a warm tub; heat from warm buttocks to the seat of a chair)
a)radiation
b)conduction
c)convection
d)evaporation
b)conduction
sharp drop in shell temperature
and conservation of core temperature.
(a) Vasoconstriction of cutaneous blood vessels
(b) Shivering:
(c) Increase in metabolic rate:
(d) Enhanced thyroxine release:
(a) Vasoconstriction of cutaneous blood vessels
Extreme emotional states (sympathetic ns) can cause a body temp increase of ~10C, and increased perspiration used to shed heat.
T or F
T
name experience when evaporation of sensible process of body temp occurs
sweating when working out
two of thermoregulatory centers:
- heat-loss centre
- heat-promoting centre
Hypothalamus receives afferent input from
- peripheral thermoreceptors (located in the
a) shell
b)core
c)thymus
a) shell
Hypothalamus receives afferent input from
-central thermoreceptors (located in the
a) shell
b)core
c)thymus
b)core
stimulate stretch receptors causes involuntary shuddering
(a) Vasoconstriction of cutaneous blood vessels
(b) Shivering:
(c) Increase in metabolic rate:
(d) Enhanced thyroxine release:
(b) Shivering:
Gradual lowering of external temperature (eg: fall to winter) leads to an increased
secretion of TRH
(a) Vasoconstriction of cutaneous blood vessels
(b) Shivering:
(c) Increase in metabolic rate:
(d) Enhanced thyroxine release:
(d) Enhanced thyroxine release:
only found in infants
which is only found in infants
(a) Vasoconstriction of cutaneous blood vessels
(b) Shivering:
(c) Increase in metabolic rate:
(d) Enhanced thyroxine release:
(d) Enhanced thyroxine release:
cold stimulates release of epinephrine and norepinephrine by adrenal medulla
termed chemical or Non shivering thermogenesis
(a) Vasoconstriction of cutaneous blood vessels
(b) Shivering:
(c) Increase in metabolic rate:
(d) Enhanced thyroxine release:
(c) Increase in metabolic rate:
brown fat
in adults can generate heat by burning triglycerides and
glucose.
what does pyrogens mean and what do they do
little fires.
chemical acts on hypothalamus triggering rise in temp
FEVER
Neuropeptide Y/agouti-related Peptide (NPY/AGRP)
a)stimulates appetit via LHA
b) suppress appetite via corticotropin releasing hormone by the VMH
a
(POMC/CART) neurons release melanocortins
a)stimulates appetit via LHA
b) suppress appetite via corticotropin releasing hormone by the VMH
b) suppress appetite via corticotropin releasing hormone by the VMH
stretch receptor inhibit or increas appetit
inhibit
What does CCK do in relation to food
satiety signal depress hunger
block NPY
what does glucagon and epinephrine do in relation to food
stimulate hunger
what is the most powerful Appetite stimulant?
grhelin
what does insulin do
satiety signal depress hunger.
when do glucagon levels rise
during fasting
does increase body temp increase or depress hunger
depress
what happens when eating in cold climates
increased eating
physiological factor in the obese
higher set point
Leptin
inhibits ___ secretion
increases ___ expression
meaning what
inhibits NPY secretion
increases cart expression
inhibition of appetite until adipose stores decrease
