Exam 3- Histology and Function of the Pituitary and Pineal Gland

Question 1

what are the three parts of the anterior lobe of the pituitary?

Answer 1

pars distalis
pars tuberalis
pars intermedia

Question 2

what are the parts of the posterior lobe of the pituitary?

Answer 2

pars nervosa
infundibulum (infundibular process and median eminence)

Question 3

what are the effects of thyrotropin releasing hormone (TRH)?

Answer 3

stimulates thyrotropes to secrete TSH (stimulates secretion thyroxin)
stimulates lactotropes to secrete prolactin
stimulates melanotropes to secrete POMC, which is processed into ACTH and other things

Question 4

what does the hypothalamus respond to?

Answer 4

impulses from CNS
circulating levels hormones
inflammatory mediators

Question 5

what are the three histologic cell types in the pars distalis?

Answer 5

acidophils
basophils
chromophobes

Question 6

are there basophils in the pars intermedia?

Answer 6

yes, but no acidophils

Question 7

what type of hormones do basophils produce?

Answer 7

tropic hormones: regulate other endocrine glands

Question 8

what type of hormones do acidophils produce?

Answer 8

hormones that act directly on target organs

Question 9

what is canine cushings disease caused by?

Answer 9

tumor in pars distalis

Question 10

what is equine pars intermedia dysfunction caused by?

Answer 10

tumor in pars intermedia

Question 11

does the hypothalamohypophyseal tract end on another neuron?

Answer 11

no; end near capillaries

Question 12

what is neurohypophysis referring to?

Answer 12

hormones released from posterior pituitary actually produced in hypothalamus

Question 13

what are herring bodies?

Answer 13

dilated portion of axon, neurosecretory vesicle storage site, hormones bound to neurophysin

Question 14

what does the pineal gland produce that helps to regulate biorhythms?

Answer 14

melatonin

Question 15

does melatonin play a role in breeding?

Answer 15

yes, in seasonal breeders

Question 16

where is the pineal gland in reptiles?

Answer 16

close to surface of brain and receives light signals from parietal organ: third eye
not snakes

Question 17

where does the pineal gland in mammals get light signals from?

Answer 17

eyes

Question 18

what is the pathway for light going from mammalian eyes to the pineal gland?

Answer 18

retina to suprachiastmatic nucleus to superior cervical ganglia to pineal gland

Question 19

what are corpora arenacea?

Answer 19

concentric calcium deposits characteristic of the pineal gland

Question 20

what are hypothalamic hormones to regulate the anterior pituitary?

Answer 20

corticotropin-releasing hormone (CRH)
thyrotropin releasing hormone (TRH)
growth hormone releasing hormone (GHRH)
somatostatin
gonadotropin releasing hormone (GnRH)
dopamine

Question 21

where do the primary capillaries in the hypothalamus drain?

Answer 21

hypophyseal portal veins

Question 22

does the pars distalis have direct arterial supply?

Answer 22

no

Question 23

true/false: the anterior pituitary is controlled only by the hypothalamus

Answer 23

false: also circulating levels hormones and paracrine secretions from cells in pituitary

Question 24

what cells release adrenocorticotropic hormone (ACTH, POMC)?

Answer 24

corticotropes: pars distalis
melanotropes: pars intermedia

Question 25

what cells release melanocyte-stimulating hormone (MSH from POMC)?

Answer 25

melanotropes: pars intermedia

Question 26

what does post-translational modification of POMC within secretory granules result in?

Answer 26

ACTH melanocyte stimulating hormone beta-endorphin

Question 27

what stimulates secretion of products of POMC?

Answer 27

corticotropes melanotropes

Question 28

are the neurons in the hypothalamohypophyseal tract myelinated?

Answer 28

no

Question 29

what can be seen in the pars nervosa?

Answer 29

nonmyelinated axons with herring bodies capillaries (fenestrated) pituicytes (glial cells)

Question 30

true/false: more melatonin is produced at night

Answer 30

true

Question 31

what does melatonin control?

Answer 31

sleep cycles and functions associated with circadian rhythm

Question 32

what does melatonin do in fall breeders when days are short?

Answer 32

increased melatonin stimulates GnRH (LH and FSH) secretion and reproduction

Question 33

what does melatonin do in spring breeders?

Answer 33

when days are short, melatonin inhibits GnRH secretion, suppressing libido

Question 34

what is in the pineal gland histologically?

Answer 34

pinealocytes glial cells (astrocytes) capillary endothelial cells sometimes melanocytes corpora arenacea ("brain sand"): concentric calcium deposits

Question 35

where in the hypothalamus is responsible for production of antidiuretic hormone and oxytocin?

Answer 35

paraventricular nucleus supraoptic nucleus

Question 36

true/false: melatonin promotes sleep in nocturnal animals

Answer 36

false: promotes activity

Question 37

true/false: all reptiles have a pineal body

Answer 37

false: not snakes