Midterm 2 - Hypothalamus - Pituitary Axis (Integration of Hormone Axis)

Question 1

what is the hypothalamus

Answer 1

the major integration center

Question 2

what does the hypothalamus regulate

Answer 2

autonomic nervous system
most of endocrine system
processes most sensory info

Question 3

what is the pituitary

Answer 3

a small gland attached to the hypothalamus

Question 4

what are the 3 parts of the pituitary

Answer 4

posterior
intermediate
anterior

Question 5

what consists of the posterior lobe of the pituitary

Answer 5

neurons from hypothalamus

Question 6

what consists of the anterior lobe of the pituitary

Answer 6

major endocrine part (glandular tissue)

Question 7

what does the intermediate lobe of the pituitary do

Answer 7

major function in amphibians and fish (MSH)

Question 8

what are the anterior lobe and intermediate often considered

Answer 8

anterior pituitary

Question 9

what is the hypothalamus composed of

Answer 9

neuroendocrine cells

Question 10

what do some neuroendocrine cells in the hypothalamus do

Answer 10

some project axons down the posterior pituitary lobe
some release factors into the pituitary stalk portal venous system to feed anterior pituitary

Question 11

where do endocrine cells from the anterior and intermediate pituitary release their hormones

Answer 11

in a second capillary network to enter systemic circulation

Question 12

what system is very important

Answer 12

the portal vascular system because not a lot of neurons in hypothalamus

Question 13

what is the role of the intermediate pituitary in mammals

Answer 13

it is unclear, possibly a source of B-endorphins

Question 14

what does the intermediate pituitary produce

Answer 14

MSH
B-LPH

Question 15

what is MSH

Answer 15

melanocyte stimulating hormone

Question 16

what does MSH do

Answer 16

increases skin pigment

Question 17

what is B-LPH

Answer 17

B-lipotropin

Question 18

what happensn to B-lipotropin

Answer 18

it is degraded to B-endorphin

Question 19

what is B-endorphin

Answer 19

an analgesia during stress (fight or flight)

Question 20

what are all hormone in intermediate pituitary derived from

Answer 20

the common gene POMC

Question 21

what is the most important regulator of extracellular fluid

Answer 21

the antidiuretic hormone

Question 22

what does anti-diuretic hormone do

Answer 22

regulates the density of aquaporins in the distal tubule and connecting duct

Question 23

where does anti-diuretic hormone act

Answer 23

in kidneys

Question 24

what does ADH increase

Answer 24

reabsorption of water

Question 25

how is ADH regulated

Answer 25

primarily by hypothalamic osmoreceptors and stretch receptors in blood vessels

Question 26

where does oxytocin primarily act on

Answer 26

uterus smooth muscle mammary gland

Question 27

what happens when oxytocin acts on uterus smooth muscle

Answer 27

contraction during parturition

Question 28

what happens when oxytocin acts on mammary gland

Answer 28

contraction increases pressure to drive milk towards excretory ducts and the teats

Question 29

what is the milk ejection reflex

Answer 29

the increase in pressure to drive milk towards ducts due to oxytocin action

Question 30

what is the receptor for oxytocin

Answer 30

G-coupled receptor with activation of PLC (Ca pathway)

Question 31

what is the secretion of oxytocin regulated by

Answer 31

several reflexes

Question 32

when might oxytocin be supplemented in dairy cattle

Answer 32

in first lactation - stimulates milk section or uterus cell contraction

Question 33

what is the master gland

Answer 33

anterior pituitary

Question 34

what does the endocrine part of the anterior pituitary contain

Answer 34

5 different cell types producing 6 different hormones

Question 35

what are proteins/glycoproteins with longer half-lives than their releasing hormones

Answer 35

thyrotrope gonadotrope corticotrope somatotrope mammotrope

Question 36

what is the releasing hormone of thyrotrope

Answer 36

TSH (thyroid stimulating hormone)

Question 37

what is the releasing hormone for gonadotrope

Answer 37

LH and FSH (gonadotropins)

Question 38

what is the releasing hormone for corticotrope

Answer 38

ACTH (adrenocorticotropin)

Question 39

what is the releasing hormone for somatotrope

Answer 39

GH (growth hormone)(somatotropin)

Question 40

what is the releasing hormone for mammotrope (lactotrope)

Answer 40

PRL (prolactin)

Question 41

what are the tropic effects of anterior pituitary

Answer 41

regulate other endocrine glands

Question 42

what is the anterior pituitary under the control of

Answer 42

under direct control (positive and/or negative) from hypothalamus

Question 43

what is the receptor for GH

Answer 43

cytokine receptor types

Question 44

what are the direct effects of GH (catabolic - break)

Answer 44

stimulates lipolysis reduces lipogenesis in adipose tissue

Question 45

what are the direct effects of GH (anabolic - build)

Answer 45

promotes synthesis of protein

Question 46

what do the direct effects of GH mainly focus on

Answer 46

metabolic control - happens regardless of age

Question 47

what are the indirect effects of GH

Answer 47

stimulates chondrocyte (cartilage cells) proliferation to increase bone growth stimulates satellite cells in muscle (muscle fibre growth) stimulate aa uptake protein synthesis

Question 48

how do the indirect effects of GH occur

Answer 48

by stimulating synthesis of IGF1 (somatomedin) and its binding proteins in the liver

Question 49

where does TSH bind

Answer 49

to its G-coupled receptor on membrane of follicular cells in thyroid gland

Question 50

what does TSH stimulate

Answer 50

cAMP which in turn stimulates the synthesis of thyroid hormones

Question 51

what is the ACTH receptor

Answer 51

a G-coupled receptor stimulating the cAMP pathway

Question 52

what does ACTH target

Answer 52

adrenal cortex

Question 53

what does ACTH stimulate

Answer 53

the mobilization of cholesterol in adrenal cortex = more substrate for cytochrome P-450 which increases the release of corticosteroids

Question 54

what is are the 2 G-protein coupled receptor of the cAMP pathway

Answer 54

LH and FSH

Question 55

what does LH stimulate in males

Answer 55

testosterone production by Leydig cells in the testis

Question 56

what does LH control in females

Answer 56

sex steroid production by the ovary and is responsible for ovulation (surge)

Question 57

what does FSH stimulate in males

Answer 57

secretion of inhibition by Sertoli cells

Question 58

what does FSH stimulate in females

Answer 58

development of follicles and secretion of sex steroid

Question 59

what type of receptor is PRL

Answer 59

cytokine receptor tupe

Question 60

what does PRL stimulate

Answer 60

the synthesis of milk proteins (casein, lactalbumin)

Question 61

what is PRL responsible for in poultry

Answer 61

the initiation and maintenance of incubation behaviour (brooding)

Question 62

how are neurohormones released from hypothalamus

Answer 62

in small amounts - bypass general circulation

Question 63

what do hypothalamic neurons receive info from

Answer 63

higher brain center (emotions) exterior (environmental and social stimuli) internal rhythms metabolic state (temp, energy level, osmolarity) endogenous hormones by feedback

Question 64

what hormones are needed early in life

Answer 64

hormones needed under tonic inhibition (GH, MSH, PRL)

Question 65

what happens to hormones needed under tonic inhibition as the hypothalamus matures

Answer 65

secretion decreases

Question 66

in mammals, where is PRL mainly

Answer 66

under dopaminergic tonic inhibition

Question 67

in birds, where is PRL mainly

Answer 67

under VIP stimulation

Question 68

what does each anterior pituitary hormone have

Answer 68

a corresponding hypothalamic releasing hormone and/or a corresponding hypothalamic inhibitory factor

Question 69

what are hypothalamic factors

Answer 69

relatively small peptides - generally fragments from pro protein of larger size

Question 70

where are releasing hormone precursors made

Answer 70

in cell bodies

Question 71

where are releasing hormone precursors transported

Answer 71

down axons to nerve endings for storage

Question 72

what is a characteristic that many hormones from the hypothalamus and pituitary have

Answer 72

they are pulsatile or episodic

Question 73

what are pulsatile hormones regulated by

Answer 73

the biological clock of hypothalamic suprachiasmatic nucleus

Question 74

what might pulsatile hormones prevent

Answer 74

may prevent the down regulation of receptors from continuous level of hormone secretion

Question 75

what can pulsatile hormones trigger

Answer 75

specific action depending on pulse frequency

Question 76

what does feedback control monitor

Answer 76

amount of hormones that have been released after stimulation

Question 77

what do circulating hormones from endocrine glands provide

Answer 77

negative feedback both to the hypothalamus and pituitary

Question 78

what does feedback serve the regulate

Answer 78

the secretion of hormones

Question 79

what are the 2 major feedback loops

Answer 79

short long

Question 80

what is the short feedback loop

Answer 80

pituitary hormones feed back to hypothalamus

Question 81

what is the long feedback loop

Answer 81

hormones from target glands feed back to the pituitary and hypothalamus

Question 82

what does negative feedback prevent

Answer 82

overstimulation