Histology, Test 1, Quarter 2, Lecture 2

Front 1

Describe the embyrological development of the adrenal gland

Back 1

2 fused primordia forming the cortex and the medulla

Front 2

What does the cortex of the adrenal gland secrete?

Back 2

steroids

Front 3

What does the medulla of the adrenal gland secrete?

Back 3

catecholamines

Front 4

What is the adrenal cortex derived from?

Back 4

intermediate mesoderm

Front 5

What is the adrenal medulla derived from?

Back 5

neural crest cells

Front 6

Describe the stroma of the adrenal gland

Back 6

Consists of a dense connective tissue capsule which sends trabecular through the cortex to the medulla

Front 7

What supports the parenchyma of the adrenal gland?

Back 7

meshwork of reticular fibers

Front 8

How is the parenchyma of the adrenal gland arranged?

Back 8

surround the vasculature

Front 9

Describe the blood supply at the capsule of the adrenal gland

Back 9

suprarenal arteries form a plexus at or within the capsule

Front 10

Name the two types are arteries that derive from the capsular plexus of the adrenal gland

Back 10

cortical and medullary

Front 11

Describe the progression of the cortical arteries in the adrenal gland

Back 11

Form loops (like arcades) just under the capsule, then progress as straight, unbranched arteries until they reach the medulla where they anastomose

Front 12

Describe the contribution of arteries to the cortex of the adrenal medulla

Back 12

Does not receive blood from the cortical or medullary arteries

Front 13

Describe the blood flow of the medullary arteries

Back 13

Travel from the capsular plexus through the trabeculae to reach the medulla where they split to form a plexus

Front 14

Where do the medullary arteries drain to?

Back 14

the venous sinuses

Front 15

Where in the adrenal gland are the venous sinuses located?

Back 15

within the medulla

Front 16

Describe the venous sinuses

Back 16

lined by a fenestrated epithelium

Front 17

Describe the blood received by the medulla

Back 17

contains both corticosteroid-rich blood from the cortical arteries and oxygen rich blood from the medullary arteries

Front 18

What do the sinus veins unite and empty into?

Back 18

the central vein

Front 19

What do adrenocortical cells secrete?

Back 19

corticosteroids

Front 20

Describe primary organelles located in the adrenocortical cells that aid in the synthesis of corticosteroids

Back 20

1) lipid droplets
2) mitochondria
3) sER

Front 21

Why are there lipid droplets in the adrenocortical cells?

Back 21

They (cholesterol esters) are the precursor to corticosteroids (the storage form).

Front 22

Describe the synthesis and secretion of corticosteroids

Back 22

No storage form, secreted via diffusion (no secretory granules)

Front 23

How do the lipid droplets of the adrenocortical cells change?

Back 23

They vary in relationship to the activity (high glucocorticoids mean low lipid droplets) and location within the cortex

Front 24

What is the importance of mitochondria within the adrenocortical cell?

Back 24

the first step of steroid synthesis and some of the last steps of glucocorticoid and mineralocorticoid synthesis occurs here

Front 25

Describe the prevalence of sER in the adrenocortical cells

Back 25

The steps of glucocorticoid synthesis that don't occur in the mitochondria occur in the sER

Front 26

Name the 3 layers of the adrenal gland cortex

Back 26

Zona glomerulosa
Zona fasiculata
Zona reticularis

Front 27

How are layers of the adrenal gland different in terms of appearance

Back 27

appearance changes based on the capillary organization

Front 28

What layer is the outermost layer of the adrenal gland?

Back 28

zona glomerulosa

Front 29

Describe the organization of cells in teh zona glomerulosa

Back 29

arranged in clumps or arcades(small cells)

Front 30

What do cells in the zona glomerulosa synthesize?

Back 30

mineralocorticoids

Front 31

What regulates the activity of the zona glomerulosa?

Back 31

the renin-angiotensin system of the kidney

Front 32

What is the thickest layer of the adrenal cortex?

Back 32

zone fasiculata

Front 33

What do cells in the zona fasiculata synthesize?

Back 33

glucocorticoids

Front 34

How are cells in the zona fasiculata organized?

Back 34

in parallel arrays around the capillaries

Front 35

What is another name for cells in the zona fasiculata layer?

Back 35

spongiocytes

Front 36

How are cells in the zona fasiculata different from other cells in the adrenal cortex?

Back 36

large, may be binucleate, large lipid droplets,

Front 37

What is the principal product of cells from the zona fasiculata?

Back 37

glucocorticoids (and to a lesser extent, adrenal androgens)

Front 38

What regulates the activity of cells in the zona fasiculata?

Back 38

ACTH

Front 39

What is the innermost layer of the adrenal cortex?

Back 39

the zona reticularis

Front 40

Describe the arrangement of cells in the zona reticularis

Back 40

anastomosing cords

Front 41

Describe the cell structure of cells in the zona reticularis

Back 41

few lipid droplets, lipofuscin granules, small, darkly staining

Front 42

What do cells of the zona reticularis secrete?

Back 42

androgens (and to a lesser extent, glucocorticoids)

Front 43

What regulates the activity of cells within the zona reticularis?

Back 43

ACTH

Front 44

Describe the location of the adrenal medulla in the adrenal gland

Back 44

Central region, surrounded by adrenal cortex

Front 45

How is the adrenal medulla similar to a sympathetic ganglia?

Back 45

derived from neural crest cells

Front 46

How is the adrenal medulla similar to postganglionic sympathetic nerve?

Back 46

receives innervation from pre-ganglionic sympathetic nerve and secrete catecholamines

Front 47

Name 2 hormones that are secreted from the adrenal medulla

Back 47

epinephrine and norepinephrine

Front 48

What is another name for cells of the adrenal medulla which contain catecholamines?

Back 48

adrenal chromaffin cells

Front 49

Describe the arrangement of adrenal chromaffin cells in the medulla

Back 49

arranged in cords around the sinuses and capillaries

Front 50

Name the two types of adrenal chromaffin cells

Back 50

adrenergic and noradrenergic

Front 51

Which cell is more frequent in the adrenal medulla: the adrenergic or the noradrenergic

Back 51

adrenergic

Front 52

Describe organelle composition of the adrenal chromaffin cells

Back 52

moderate rER and prominent Golgi, secretory vesicles,

Front 53

How is dopamine created in the adrenal chromaffin cell?

Back 53

converted from tyrosine in the cytoplasm

Front 54

What is the fate of dopamine in the adrenal chromaffin cell?

Back 54

converted to norepinephrine in the secretory vesicle

Front 55

How can norepinephrine be converted to epinephrine?

Back 55

transported to the cytoplasm from the secretory vesicle where PNMT converts it to epinephrine

Front 56

Other than epinephrine or norepinephrine, what is contained and secreted within the secretory vesicles?

Back 56

enkephalins

Front 57

How does the level of glucocorticoids present effect the level of adrenergic vs. noradrenergic cells in the adrenal medulla?

Back 57

high levels of glucocorticoids are needed to make PNMT which can convert noradrenergic cells to adrenergic cells

Front 58

What do adrenal chromaffin cells derive from?

Back 58

neural crest cells

Front 59

Other than adrenal chromaffin cells, what can neural crest cells differentiate into in the adrenal medulla

Back 59

neurons

Front 60

How do glucocorticoids affect neural crest cell differentiation?

Back 60

Glucocorticoids tend to favor the differentiation into adrenal chromaffin cells rather than neurons

Front 61

What types of cells might be present in the adrenal medulla

Back 61

adrenal chromaffin cells (both adrenergic and noradrenergic) and neurons

Front 62

What is the primary function of the adrenal gland in the fetus?

Back 62

major secreter of androgens

Front 63

What effect do androgens from the fetal adrenal gland have on development?

Back 63

They migrate to the placenta where they are converted into estrogens which are important for the maintenance of pregnancy

Front 64

What and where is the fetal zone of the fetal adrenal gland

Back 64

between the cortex and the medulla. Functions to secrete androgens

Front 65

When does the fetal adrenal gland lose the "fetal zone"

Back 65

within 2-3 weeks after birth

Front 66

Describe the parenchyma of the thyroid gland

Back 66

thyroid follicles

Front 67

Describe the structure of lymphoid follicles

Back 67

spherical structures that vary in size and number

Front 68

Describe the composition of lymphoid follicles

Back 68

Consist of epithelium surrounding a central lumen

Front 69

Describe the contents of the lumen in the lymphoid follicle

Back 69

material called colloid, which is rich in thyroglobulin

Front 70

What is the chief protein of the lymphoid follicle?

Back 70

thyroglobulin

Front 71

Describe the epithelium of lymphoid follicles

Back 71

simple (height size depends on activity of the follicle)

Front 72

Describe the size and epithelium of inactive lymphoid follicles

Back 72

large follicles, simple squamous epithelium

Front 73

Describe the size and epithelium of active lymphoid follicles

Back 73

Small, simple columnar epithelium

Front 74

Describe the stroma of the lymphoid follicle

Back 74

loose connective tissue running between the follicles, and a basal membrane encapsulating follicles

Front 75

Describe the blood supply to the lymphoid follicle

Back 75

basal lamina is lined by fenestrated capillaries

Front 76

Describe the lymphatics of the thyroid gland

Back 76

run throughout the loose connective tissue, but not closely associated with the follicle

Front 77

Describe the capsule of the thyroid

Back 77

composed of dense connective tissue, send trabeculae into the thyroid to support the follicles

Front 78

Name the two cells associated with the lymphoid follicle

Back 78

parafollicular cells and thyroid follicular cells

Front 79

What in the lymphoid follicles are the parafollicular cell and thyroid follicular cell located?

Back 79

typically in the epithelium

Front 80

What is the major cell lining the thyroid follicle?

Back 80

thyroid follicular cells

Front 81

What do thyroid follicular cells do?

Back 81

synthesize triiodothryonine and thyroxine (as well as thyroglobulin and components of the colloid)

Front 82

What regulates activity of the thyroid follicular cell?

Back 82

stimulated by thyroid stimulating hormone

Front 83

Describe the apical surface of the thryoid follicular cell

Back 83

contains numerous microvilli. In very active cells, phagocytic pseudopod is also noticed projecting into the lumen

Front 84

What separates the apical surface from the basolateral surface of the thyroid follicular cell?

Back 84

tight junctions

Front 85

Describe the organelle composition of thyroid follicular cells

Back 85

prominent rER, prominent Golgi, phagocyic vacuoles and lysosomes

Front 86

What are T3 and T4 derivatives of?

Back 86

iodinated tyrosines

Front 87

Where is the tyrosine that becomes iodinated to form T3 and T4?

Back 87

a part of the thyroglobulin molecule

Front 88

How does iodinated thyroglobulin relate to T3 and T4?

Back 88

iodinated thyroglobulin is the storage form of T3 and T4

Front 89

How are T3 and T4 released?

Back 89

degraded from iodinated thyroglobuin into T3 and T4, then endocytosed

Front 90

Describe the synthesis of thyroglobulin

Back 90

synthesized on ribosomes on the rER, transported into the lumen where the carbohydrate chain is added. Protein moved to Golgi where carbohydrate is modified. Golgi releases it to the apical surface in a vesicle. Vesicle is expelled into lumen

Front 91

What enzyme is responsible for the iodination of tyrosines within thyroglobulin?

Back 91

thyroperoxidase

Front 92

Where is thyroperoxidase located within the thryoid gland?

Back 92

on the apical microvilli as an integral protein

Front 93

Where does iodination of the tyrosine occur?

Back 93

while the thyroglobulin protein is in the lumen

Front 94

How is iodine collected for iodinated of tyrosines in the thyroid gland?

Back 94

by an active transport mechanism which moves I- all the way across the thyroid follicle cells into the lumen

Front 95

How does goiter develop?

Back 95

if there is a lack of I-

Front 96

What happens if there is not enough iodine in the thyroid?

Back 96

thyroid becomes enlarged due to the pituitary increased TSH which in turn results in hyperplasia and hypertrophy of the thyroid

Front 97

What triggers the degradation of thyroglobulin in the thyroid gland?

Back 97

the need for T3 and T4

Front 98

Describe the process of thyroglobulin degradation

Back 98

phagocytic vesicles fuse with lysosomes to degrade thyroglobulin into secondary lysosomes. From here, thyroglobulin is degraded into individual amino acids (T3 and T4) which is secreted into the blood via the fenestrated capillaries

Front 99

Where are parafollicular cells located?

Back 99

Within the follicular epithelium of the thyroid follicles, but much less numerous than the thyroid follicular cells

Front 100

What do parafollicular cells secrete?

Back 100

calcitonin

Front 101

Describe the shape and size of the parafollicular cells

Back 101

Larger than the thyroid follicular cells, however the thyroid follicular cells overarch the parafollicular cells such that they do not reach the follicular lumen

Front 102

Describe the organelle structures of the parafollicular cells

Back 102

moderate rER, and prominent Golgi, numerous small secretory granules

Front 103

Describe how the cells of the thyroid follicle represent the dual embryological origin of the organ

Back 103

parafollicular cells derive from neuralcrest cells of the ultimobranchial bodies and the thyroid follicular cells derive from thyroid gland proper

Front 104

Where is the parathyroid gland located?

Back 104

Usually on top of the thyroid gland, but sometimes it can be located within in, or distant from it

Front 105

How is the parenchyma of the parathyroid gland arranged?

Back 105

around the blood capillaries

Front 106

Name the 2 parathyroid parenchyma cells

Back 106

parathyroid chief cell
oxyphil cell

Front 107

What is the primary cell of the parathyroid gland?

Back 107

parathyroid chief cell

Front 108

What do parathyroid cells secrete?

Back 108

parathyroid hormone

Front 109

What does parathyroid hormone do?

Back 109

causes an increase in Ca++

Front 110

How can parathyroid hormone increase Ca in the blood?

Back 110

stimulating bone resorption indirectly through osteoblasts

Front 111

Describe the arrangement of parathyroid cells within the parathyroid gland

Back 111

arranged in cords around the capillaries

Front 112

Describe the defining characteristics of parathyroid chief cells

Back 112

polygonal or cuboidal, light-staining cytoplasm, round euchromatic nucleus

Front 113

Describe how oxyphil cells differ from the parathyroid chief cells

Back 113

larger, numerous mitochondria, small heterochromatic nucleus, darkly staining cytoplasm

Front 114

What is the function of the oxyphil cell?

Back 114

unknown

Front 115

What are oxyphil cells derived from?

Back 115

Unknown, but believed that believe parathyroid chief cells

Front 116

Describe the pattern of presence of oxyphil cells in humans

Back 116

rare in children, grow more common as you age.

Front 117

Describe the capsule of the parathyroid gland

Back 117

thin connective tissue capsule

Front 118

Describe the arrangement of nerves, blood supply, and lymphatics in the parathyroid gland

Back 118

enter the gland with trabeculae from the capsule. Blood supply branches which is what the cells arrange themselves around

Front 119

Describe another type of cell present in the parathyroid gland that is NOT one of the parenchymal cells

Back 119

adipocytes (sometimes up to half the cells are adipocytes)