Hypothalamus

Question 1

What does stimulation of a ventromedial satiety center do?

Answer 1

Inhibits the urge to eat.

Question 2

What is the result of bilateral destruction of the ventromedial satiety center?

Answer 2

Overeating and gross obesity.

Question 3

Where does the hormone act in the kidney?

Answer 3

Distal convoluted tubules and collecting ducts.

Question 4

What maintains osmolarity in the blood?

Answer 4

Regulating water reuptake in the distal convoluted tubules.

Question 5

What happens with a 1% increase in osmotic pressure?

Answer 5

Plasma is diluted to normal levels by increased water uptake.

Question 6

What condition results from reduced production of ADH?

Answer 6

Diabetes insipidus.

Question 7

How much urine can a patient with diabetes insipidus urinate per day?

Answer 7

18 to 20L.

Question 8

What is the principal function of oxytocin?

Answer 8

To participate in a neurohumoral reflex to release milk during suckling.

Question 9

What hormones are secreted by magnocellular neurons in the hypothalamus?

Answer 9

• Antidiuretic hormone (ADH) * Oxytocin

Question 10

What is the role of the hypothalamo-hypophyseal tract?

Answer 10

Conveys hormones to the posterior pituitary.

Question 11

What stimulates the release of oxytocin?

Answer 11

Suckling.

Question 12

What does oxytocin stimulate in the breast?

Answer 12

Expression of milk.

Question 13

What effect does oxytocin have during labor?

Answer 13

Stimulates uterine muscle contractions.

Question 14

What is the appestat?

Answer 14

The interplay between the lateral and ventromedial nuclei regulating caloric and nutrient intake.

Question 15

What reactions occur to conserve body heat?

Answer 15

• Peripheral vasoconstriction * Increased body metabolism * Shivering * Decreased respiratory rate

Question 16

What mechanisms facilitate heat loss when body temperature increases?

Answer 16

• Dilation of peripheral blood vessels * Increased sweating * Increased respiratory rate

Question 17

What hormone stimulates the release of adrenal cortical steroids?

Answer 17

Adrenocorticotropic hormone (ACTH).

Question 18

What is the function of growth hormone (GH)?

Answer 18

Promotes growth of long bones and possibly other tissues.

Question 19

What does prolactin do?

Answer 19

Stimulates development of mammary glands and lactation.

Question 20

Where do hormones from the anterior pituitary drain?

Answer 20

Into capillaries that drain into the cavernous sinus.

Question 21

What is the hypothalamus’s role in body homeostasis?

Answer 21

• Reproduction * Growth and metabolism * Food and fluid intake * Attack and defense * Temperature control * Sleep-wake cycle * Memory

Question 22

What is the effect of stimulating the anterior hypothalamic area?

Answer 22

Produces parasympathetic effects.

Question 23

What is the effect of stimulating the posterior hypothalamic area?

Answer 23

Produces sympathetic effects.

Question 24

What type of neurons produce neurosecretion to control the anterior pituitary?

Answer 24

Parvocellular neuroendocrine cells.

Question 25

What is the vascular system that carries neurosecretion to the anterior lobe of the pituitary?

Answer 25

Pituitary portal system.

Question 26

What hormone shares the same releasing factor as LH?

Answer 26

Follicle stimulating hormone (FSH).

Question 27

What is the axonal transport mechanism used by ADH?

Answer 27

Transport to the capillaries of the posterior pituitary.

Question 28

What are Herring bodies?

Answer 28

Axonal swellings containing secretory granules for hormone release.

Question 29

hypothalamus location

Answer 29

occupies the side walls and floor of the third ventricle

Question 30

homeostatic functions the hypothalamus controls

Answer 30

reproduction growth and metabolism food and fluid intake attack and defence temperature control sleep-wake cycle memory

Question 31

which cells of the hypothalamus are sensitive to blood concentration of hormones from the ant pit

Answer 31

parvocellular (small) neuroendocrine cells of the preoptic and tuberal regions

Question 32

tuberoinfundibular tract what do APs of these neurons cause

Answer 32

hypothalamic neurons produce secretions that pass down their axons to reach the stalk of the pit gland calcium dependent exocytosis of releasing or inhibitory hormones (trophic)

Question 33

control of release hypothalamic neurons

Answer 33

axonal connections of hypothalamus and other brain areas

Question 34

pituitary portal system

Answer 34

vascular system that carries neurosecretions to ant pit capillaries of infundibulum drain into portal vessels which pass into ant pit break up to form a second capillary bed which bathes endocrine cells

Question 35

arterial supply of the pit gland

Answer 35

comes from branches of internal carotid artery one set of branches supplies a capillary bed in infundibulum

Question 36

hormones secreted by ant pit and their functions

Answer 36

prolactin: development of mammary glands and lactation TSH: stimulates thyroid to synthesise and release thyroxine and triiodothyronine adrenocorticotrophic hormone: stimulates adrenal cortex GH: growth of long bones and possibly other tissues FSH: growth of ovaries/seminiferous tubules and section of estrogen/production of spermatozoa LH: together with FSH induces ovulation

Question 37

what give rise to the hypothalamo-hypophyseal tract where does it terminate

Answer 37

magnocellular (large) neurons in the supraoptic and paraventricular nuclei terminates in the pos pit

Question 38

Herring bodies

Answer 38

axonal swellings containing secretory granules provide local depot of granules for release by smaller swellings into capillary bed

Question 39

arterial supply of pit gland

Answer 39

receives a direct supply from another set of hypophyseal arteries

Question 40

route of hormone release from pituitary gland

Answer 40

from both ant and pos pit drain into capillaries drain into cavernous sinus into general circulaiton

Question 41

how is osmolarity in the blood maintained by ADH

Answer 41

regulating water uptake in DCTs

Question 42

result of reduced production of ADH

Answer 42

diabetes insipidus patient can urinate 18 to 20L per day

Question 43

principal function of oxytocin

Answer 43

participates in neurohumoral reflex to cause release of milk, when an infant is suckling

Question 44

afferent limb of lactation reflex

Answer 44

impulses travel from nipple to hypothalamus via spinoreticular tract oxytocin is liberated by magnocellular neurons in supraoptic and paraventricular nuclei

Question 45

effect of oxytocin at breast

Answer 45

stimulates myoepithelial cells surrounding lactiferous ducts

Question 46

effect of oxytocin during labour

Answer 46

stimulates uterine muscle contraction

Question 47

how is heat sensed by hypothalamus how is cold sensed by hypothalamus

Answer 47

when there is increased temperature the heated blood passes through the ant hypothalamic area heat sensitive neurons activate cool blood passes through pos hypothalamic area area

Question 48

reactions to reduce body temperature

Answer 48

dilation of peripheral blood vessels beneath skin increased sweating increased resp rate

Question 49

reactions to conserve heat

Answer 49

peripheral vasoconstriction increased metabolism shivering of voluntary muscles decreased resp rate

Question 50

what determines the appestat

Answer 50

baseline for caloric and nutrient intake by interplay between lateral and ventromedial nuclei

Question 51

stimulation of lateral hypothalamic satiety centre destruction

Answer 51

excessive eating refusal to eat

Question 52

stimulation of ventromedial satiety centre destruction

Answer 52

inhibits urge to eat overeating and obesity

Question 53

autonomic effects of ant and pos hypothalamic areas

Answer 53

ant: parasympathetic effects pos: sympathetic effects