Endocrine System

Question 1

Endocrine cells are typically ____

Answer 1

Epithelial cells

Question 2

Endocrine cells produce secretions called ____

Answer 2

Hormones

Question 3

What are hormones?

Answer 3

Secretary products of endocrine cells, serve as signaling molecules (effectors) to regulate activities of various cells, tissues, and organs of the body

Question 4

Hormones act on specific cells with specific ____

Answer 4

Receptor sites

Question 5

3 chemical classes of hormones

Answer 5

1. Steroids
2. Small peptides, polypeptides, proteins
3. Amino acids, arachidonic acid analogs, inflammatory proteins

Question 6

3 endocrine distribution control mechanisms

Answer 6

1. Endocrine secretion
2. Paracrine secretion
3. Autocrine secretion

Question 7

endocrine secretion

Answer 7

*most common
hormones enter blood stream (fenestrated capillaries) and transported to target cells

Question 8

paracrine secretion

Answer 8

hormones act on adjacent cells or diffuse to nearby target cells

Question 9

autocrine secretion

Answer 9

hormones act on same endocrine cell

Question 10

The pituitary gland is attached to the hypothalamus by the ____ and ____

Answer 10

Infundibulum (neural)
Pars tuberalis (vascular)

Question 11

2 functional components of pituitary gland

Answer 11

Anterior lobe
Posterior lobe

Question 12

What type of tissue is the anterior lobe of the pituitary gland?

Answer 12

Glandular epithelial tissue

Question 13

What is Rathke’s pouch?

Answer 13

[anterior lobe] derived from evagination of the ectoderm of the oropharynx toward the brain

Question 14

components of anterior lobe of pituitary

Answer 14

• pars distalis/anterior
• pars intermedia
• pars tuberalis

Question 15

what comprises most of the anterior lobe of pituitary?

Answer 15

pars distalis/anterior

Question 16

pars tuberalis

Answer 16

forms highly vascular sheath around infundibulum which connects to hypothalamus (hypothalamic-hypophyseal portal system)

Question 17

what type of tissue is the posterior lobe of the pituitary?

Answer 17

neural secretory tissue

Question 18

posterior lobe of pituitary is derived from…

Answer 18

down growth of neuroectoderm of lower 3rd ventricle of developing brain

Question 19

components of posterior lobe of pituitary (neurohypophysis)

Answer 19

infundibulum
pars nervosa

Question 20

infundibulum

Answer 20

contains neurosecretory axons emanating from hypothalamus (hypothalamic-hypophyseal tract)

Question 21

pars nervosa

Answer 21

contains neurosecretory axons and their endings (arising from hypothalamus)

Question 22

hypothalamic-hypophyseal tract

Answer 22

axons from hypothalamus carry hormones secreted by neurons from hypothalamus through the infundibulum into the pars nervosa

Question 23

hypothalamic-hypophyseal portal system

Answer 23

blood vessels carry regulatory peptides from neurons in hypothalamus to cells of anterior pituitary (pars distalis) where they control cell secretion

Question 24

hormones of adenohypophysis (anterior pituitary/lobe)

Answer 24

tropic and non-tropic hormones

Question 25

tropic hormones

Answer 25

regulate other endocrine glands (ACTH, TSH, FSH, LH)

Question 26

non-tropic hormones

Answer 26

directly act on target organs that are not endocrine (GH, PRL)

Question 27

organization of cells of pars distalis

Answer 27

clumps & cords separated by fenestrated capillaries and supporting reticular CT

Question 28

3 cell types of pars distalis

Answer 28

- chromophils: basophils, acidophils - chromophobes

Question 29

chromophils pick up staining colour due to...

Answer 29

their hormone content

Question 30

acidophils produce and secrete...

Answer 30

GH - growth hormone (somatotropin) PRL - prolactin

Question 31

basophils produce and secrete...

Answer 31

- FSH - follicle stimulating hormone - LH - luteinizing hormone (ICSH in men, interstitial cell stimulating hormone) - ACTH - adrenocorticotropic hormone - TSH - thyroid stimulating hormone

Question 32

pars intermedia structure

Answer 32

- thin remnant of posterior wall of Rathke's pouch, borders pars distalis - surrounds series of colloid filled cysts and/or intraglandular cleft (vestigial cleft) representing residual lumen of Rathke's pouch

Question 33

pars nervosa is not...

Answer 33

an endocrine gland

Question 34

function of pars nervosa

Answer 34

storage site for hypothalamus neurosecretions and release of hormones into fenestrated capillaries (endocrine release)

Question 35

pars nervosa hormones accumulate in axonal terminal dilations called ____

Answer 35

Herring bodies (neurosecretory bodies)

Question 36

Pars nervosa hormones in Herring bodies

Answer 36

- ADH - antidiuretic hormone/vasopressin - Oxytocin

Question 37

what is the predominant cell of the pars nervosa?

Answer 37

pituicytes (resemble astrocytes)

Question 38

function of vasopressin/ADH

Answer 38

increases water permeability of renal collecting ducts

Question 39

function of Oxytocin

Answer 39

stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle

Question 40

the hypothalamus regulates pituitary gland activity via ____

Answer 40

negative feedback loop

Question 41

thyroid gland function is essential to...

Answer 41

normal growth and development

Question 42

what is the structural and functional unit of the thyroid gland?

Answer 42

thyroid follicle

Question 43

thyroid follicle is formed by...

Answer 43

follicular cells (simple cuboidal epithelium with microvilli)

Question 44

follicular cells produce...

Answer 44

thyroid hormones: T3 and T4 (thyroxine)

Question 45

function of T3 and T4

Answer 45

- regulate cell and tissue basal metabolism and heat production - influence body growth and development

Question 46

thyroid follicles contain ____

Answer 46

colloid

Question 47

colloid

Answer 47

gel-like mass containing thyroglobulin

Question 48

thyroglobulin

Answer 48

inactive precursor form of thyroid hormone

Question 49

parafollicular cells location

Answer 49

periphery of follicular cells

Question 50

parafollicular cells produce ____

Answer 50

calcitonin

Question 51

calcitonin

Answer 51

lowers blood Ca by inhibiting osteoclast activity

Question 52

epithelial cells of parathyroid

Answer 52

principal cells oxyphil cells

Question 53

principal (chief) cells produce ____

Answer 53

PTH - parathyroid hormone

Question 54

PTH (parathyroid hormone) function

Answer 54

increases blood Ca

Question 55

3 targets of PTH

Answer 55

1. osteoblasts 2. kidney 3. small intestine

Question 56

oxyphil cells

Answer 56

function not fully understood, thought to be exhausted principal cells

Question 57

regions of adrenal glands

Answer 57

cortex & medulla

Question 58

adrenal cortex secretes ____

Answer 58

steroid hormones

Question 59

3 zones of adrenal cortex

Answer 59

1. zona glomerulosa 2. zona fasciculata 3. zona reticularis

Question 60

zona glomerulosa produces ____, such as _____

Answer 60

mineralocorticoids: aldosterone

Question 61

aldosterone function

Answer 61

major regulator of Na & K balance by increasing kidney absorption of Na and secretion of K

Question 62

zona fasciculata produces ____, such as ____

Answer 62

glucocorticoids: cortisol

Question 63

cortisol function

Answer 63

- gluconeogenesis (& glycogenolysis) - immune & inflammatory reponses

Question 64

cortisol is regulated by ____

Answer 64

ACTH (anterior pituitary)

Question 65

zona reticularis produces ____, such as ____

Answer 65

weak androgens: DHEA (dehydroepiandrosterone)

Question 66

DHEA is converted to ____

Answer 66

testosterone (& estrogen)

Question 67

what are the cells of the adrenal medulla

Answer 67

parenchymal cells = chromaffin cells

Question 68

what are chromaffin cells?

Answer 68

specialized secretory cells supported by reticular fibers and many wide-open sinusoidal capillaries

Question 69

chromaffin cells secrete ____

Answer 69

catecholamines: epinephrine & norepinephrine

Question 70

function of catecholamines

Answer 70

- regulate stress response - stimulate glycogen breakdown (elevate blood glucose)

Question 71

epinephrine is stored in....

Answer 71

small, less electron dense granules

Question 72

norepinephrine is stored in...

Answer 72

larger, more electron dense granules

Question 73

epinephrine function

Answer 73

- increase HR - dilate bronchioles - dilate arteries of cardiac & skeletal muscle

Question 74

norepinephrine function

Answer 74

- constrict blood vessels of digestive system & skin - increase blood flow to heart, muscles, brain

Question 75

2 main types of parenchymal cells of the pineal gland

Answer 75

1. pinealocytes 2. interstitial glial cells (neuroglial cells - modified astrocytes)

Question 76

pinealocytes produce ____

Answer 76

melatonin

Question 77

melatonin function

Answer 77

(tryptophan derivative) regulate daily body rhythms and day/night cycle (circadian rhythm)

Question 78

interstitial glial cell function

Answer 78

unmyelinated tracts of sympathetic fibers associated with photoreceptor neurons in the retina, **run into pinealocytes to stimulate melatonin release in periods of darkness**

Question 79

copora arenacea

Answer 79

"brain sand" - characteristic feature of the pineal gland - formed by mineralization of extracellular protein deposits - increases in size & number with age