Guyton Phys 75: Pituitary Hormones And Their Control By The Hypothalamus

Front 1

where is the anterior pituitary derived from

Back 1

Rathke's pouch - invagination of pharyngeal epithelium

Front 2

growth hormone

Back 2

promotes growth of entire body by affecting protein formation, cell multiplication, and cell differentiation

Front 3

adrenocorticotropin (corticotropin)

Back 3

controls secretion of some of adrenocortical hormones (affect metabolism of glucose, proteins, and fats)

Front 4

TSH (thyrotropin)

Back 4

controls rate of secretion of thyroxin and triiodothyrodine (control rates of most intracellular chemical rxns in body)

Front 5

prolactin

Back 5

promotes mammary gland dvlp and milk production

Front 6

FSH and LH

Back 6

control growth of ovaries and testes as well as hormonal/reproductive activities

Front 7

ADH (vasopressin)

Back 7

controls rate of water excretion into urine

Front 8

oxytocin

Back 8

helps express milk from glands of the breast to nipples during suckling

Front 9

how many cell types can be differentiated in the anterior pituitary

Back 9

at least five

Front 10

somatotropes secrete

Back 10

human growth hormone (hGH)

Front 11

corticotropes secrete

Back 11

adrenocorticotropin (ACTH)

Front 12

thyrotropes secrete

Back 12

TSH

Front 13

gonadotropes secrete

Back 13

gonadotropic homones including LH and FSH

Front 14

Lactotropes secrete

Back 14

prolactin (PRL)

Front 15

what percent of anterior pituitary cells are somatotrophes

Back 15

30-40%

Front 16

what percent of anterior pituitary cells are corticotrophes

Back 16

~20%

Front 17

somatotropes stain with

Back 17

acid dyes an are called acidophiles

Front 18

where are posterior pituitary hormones made

Back 18

in magnocellular neurons in the supraoptic and paraventricular nuclei of the hypothalamus

Front 19

what controls secretion of posterior pituitary hormones

Back 19

nerve signals that originate in hypothalamus

Front 20

what controls secretion of anterior pituitary hormones

Back 20

controled by hormones called hypothalamic releasing and hypothalamic inhibitory hormones/factors secretes within hypothalamus and conducted to anterior pituitary via hypothalamic-hypophysial portal vessels (minute blood vessels)

Front 21

what makes/secretes the hypothalamic releasing and inhibitory hormones

Back 21

various parts of hypothalamus - send nerve fibers to median eminence and tuber cinereum and secrete hormones

Front 22

Thyrotropin-releasing hormones (TRH)

Back 22

causes release of TSH

Front 23

corticotropin-releasing hormones (CRH)

Back 23

causes release of ACTH

Front 24

GH releasing hormone (GHRH)

Back 24

causes release of GH

Front 25

GH inhibitory hormone aka somatostatin

Back 25

inhibits release of GH

Front 26

Gonadotropin releasing hormone (GnRH)

Back 26

causes release of LH and FSH

Front 27

Prolactin inhibitory hormone (PIH)

Back 27

inhibition of prolactin secretion

Front 28

specific metabolic affects of GH

Back 28

1) increase rate of protein synthesis 2) increased mobilization of fatty acids and increased use of fatty acids 3) decreased rate of glucose utilization

Front 29

main mechanism behind protein sparing with GH

Back 29

mobilization of fatty acids provides energy source and prevents their breakdown

Front 30

how long does it take fats and proteins to be mobilized/synthesized by GH

Back 30

several hours; enhancement of protein synthesis can begin in minutes

Front 31

what can excessive GH cause in liver

Back 31

excess acetoacetic acid release causing ketosis and sometimes fatty liver

Front 32

GH carbohydrate effects

Back 32

1) decreased glucose uptake 2) increased glucose production by liver 3) increased insulin secretion

Front 33

when does GH fail to cause growth

Back 33

lack a pancreas; carbs excluded from diet - insulin activity necessary for GH effectiveness

Front 34

what causes increased growth of skeletal frame with GH

Back 34

1) increased deposition of protein by chondrocytic and osteocytic cells 2) increased rate of reproduction of these cells 3) specific effect of converting chondrocytes into osteogenic cells

Front 35

example of a bone that can grow after adolescence

Back 35

jaw bones - causes forward protrusion of chin and lower teeth

Front 36

Insulin-like growth factors (IGFs)

Back 36

produced by liver and some other tissues in response to GH and cause GH effects

Front 37

half life of GH in blood

Back 37

~20 minutes

Front 38

somatomedin C (IGF-1) half-life in blood

Back 38

20 hours - attaches strongly to carrier protein in plasma

Front 39

what can stimulate GH secretion

Back 39

1) starvation 2) hypoglycemia or low fatty acids 3) exercise 4) excitement 5) trauma 6) first 2 hours of deep sleep

Front 40

how can GH level return to normal after severe malnutrition (kwashiorkor)

Back 40

carbs not enough, also need protein treatment

Front 41

part of hypothalamus that secretes GHRH

Back 41

ventromedial nucleus - sensitive to blood glucose concentration

Front 42

what transmitters can increase the rate of GH secretion within hypothalamus neuronal systems

Back 42

catecholamines, dopamine, and serotonin

Front 43

what does GHRH activate

Back 43

adenylyl cyclase system increasing cAMP

Front 44

short and long term effects of GHRH

Back 44

short term increase in Ca2+ in cell and GH vesicle fusion; long-term increase of transcription in nucleus

Front 45

feedback of GH

Back 45

not sure if mediated by GHRH inhibition or somatostatin enhancement

Front 46

panhypopituitarism

Back 46

decreased secretion of all anterior pituitary hormones

Front 47

dwarfism general cause

Back 47

generalized deficiency of anterior pituiary secretion during childhood

Front 48

puberty and panhypopituitarism dwarfism

Back 48

doesn't pass through puberty and never secretes enough gonadotropic hormones to dvlp adult sexual fxns; in 1/3 only GH deficient and they DO mature

Front 49

deficiency of african pygmy and Levi-Lorain dawrfs

Back 49

GH secretion normal to high, but inability to form somatomedin C

Front 50

panhypopituitarism in adults cause

Back 50

tumorous conditions: craniopharyngiomas or chromophobe tumors compressing pituitary gland; thrombosis of pituitary blood vessels

Front 51

general effects of adult panhypopituitarism

Back 51

hypothyroidism, depressed production of glucocorticoids, and supressed secretion of gonadotropic hormones; lethargic person who is gaining weight

Front 52

what percent of giants dvlp full blown type II diabetes

Back 52

~10%

Front 53

what effect does acromegaly have on vertebrae

Back 53

kyphosis (hunch back)

Front 54

What soft tissues are most affected in acromegaly

Back 54

tongue, liver, kidneys

Front 55

glial-like cells n posterior pituitary

Back 55

pituicytes

Front 56

fxn of pituicytes

Back 56

supporting structure for large numbers of terminal nerve fibers and endings

Front 57

where is ADH primarily formed

Back 57

supraoptic nuclei

Front 58

where is oxytocin primarily formed

Back 58

paraventricular nuclei

Front 59

what is secreted along with ADH/oxytocin when released

Back 59

neurophysin - no known fxn after leaving nerve terminal

Front 60

stucture of ADH vs oxytocin

Back 60

almost identical - explains partial fxnal similarities

Front 61

aquaporins

Back 61

special vesicles with highly water-permeable pores

Front 62

what second messenger does ADH set into action

Back 62

adenylyl cyclase system increasing cAMP

Front 63

how quickly does ADH work on collecting ducts

Back 63

5-10 minutes

Front 64

how quickly does the process reverse in absence of ADH

Back 64

5-10 minutes

Front 65

possible location of osmoreceptors controlling ADH secretion

Back 65

in hypothalamus, organum vasculosum

Front 66

where/what is the organum vasculosum

Back 66

highly vascular structure in the anteroventral wall of the third ventricle

Front 67

low vs high ADH concentration

Back 67

low ADH causes water conservation in kidney; high causes constriction of arterioles

Front 68

atria and ADH secretion

Back 68

when stretched, send signal to brain to inhibit ADH secretion

Front 69

oxytocin and lactation

Back 69

causes milk to be expressed from alveoli into ducts of breast; causes contration of myoepithelial cells surrounding alveoli