Histology-Endocrine System

Front 1

What does the term "endocrine" indicate?

Back 1

that a gland releases its secretory product (chemical messenger; hormone) into the bloodstream rather than onto a free body surface

Front 2

Hormones travel in the blood until when?

Back 2

until they bind to a specific receptor in a target cell, where they exert their physiological effect

Front 3

In each of the endocrine glands, the morphology of the cell reflects the nature of the hormone and means of release: if the hormone is a
-steroid, the cell synthesizes it on ____
-peptide or polypeptide, the cell synthesizes it on ____
-glycoprotein, the cell synthesizes it on ____

Back 3

-smooth ER
-rough ER
-smooth and rough ER

Front 4

T/F
-If the hormone is synthesized and released immediately, there is no storage phase
-If the hormones are synthesized and stored before release, no granules are present.

Back 4

True
False- intracellular (or extracellular follicles) secretory granules are present

Front 5

Whats the origin of endocrine glands?

Back 5

epithelial origin (except posterior pituitary, parafollicular cells, and adrenal medulla); detach from epithelium of origin (ductless glands)

Front 6

Endocrine glands have ___ capillaries or sinusoids have numerous ___.

Back 6

-highly vascularized
-fenestrations

Front 7

What do endocrine glands do?

Back 7

secrete hormonal products directly into bloodstream

Front 8

Hormones:
-regulate ____
-act in (small/large) concentrations
-Can be ____ derivatives
-Can affect ___ target organs
-Activity is dependent on the presence of specific ____

Back 8

-cellular activity
-small (ng-pg range)
-proteins, peptides, steroids, or amino acid
-one or several
-receptors

Front 9

Which gland is located at the base of the brain in a shallow depression of the sphenoid bone, called the sella tursica?

Back 9

Pituitary gland (hypophysis)

Front 10

What does the pituitary gland secrete?

Back 10

large number or hormones to activate many peripheral endocrine cells

Front 11

Which gland is bean shaped and ~12x10x9mm in size and weighing 0.4-0.9gm in adult?

Back 11

pituitary gland

Front 12

Input from several neural systems influence the endocrine system via the hypothalamus such as what?

Back 12

spinal cord, limic system, medulla and brainstem, retina

Front 13

The pituitary gland is normally separated into subregions based on what criteria?

Back 13

embryologic origin or anatomic location

Front 14

What are the divisions of the pituitary gland based on embyronic orgins?

Back 14

neurohypophysis and adenohypophysis

Front 15

What is the neurohypophysis of the pituitary gland derived from and composed of?

Back 15

-a downgrowth of the brain (diencephalon)
-nervous tissue

Front 16

What is the neurohypophysis of the pituitary gland subdivided into?

Back 16

median eminence
infundibular stalk
pars nervosa

Front 17

What is the adenohypophysis of the pituitary gland derived from and composed of?

Back 17

-dorsal evagination (called Rathke's pouch) of the embryonic oral cavity (ectoderm)
-glandular tissue

Front 18

What is the adenohypophysis of the pituitary subdivided into?

Back 18

Pars tuberalis
Pars intermedia
Pars distalis
(there may be a lumen bw the pars distalis and pars intermedia that is a remnant of Rathke's pouch)

Front 19

What are the divisions of the pituitary gland based on morphology and what do they include?

Back 19

-Posterior lobe includes the pars nervosa and pars intermedia
-Hypophyseal stalk includes the pars tuberalis and infundibular stalk
-Anterior lobe is the same as the pars distalis

Front 20

What does the blood supply of the pituitary gland consist of?

Back 20

the cells of the adenohypophysis are activated by releasing factors produced in the hypothalamus and carried to them in the blood

Front 21

Blood supply to the pituitary gland:
-arises from ___
-branches of the ____
-Anastomose around the median eminence of the ____
-Send branches into it to form the so called ____; branches of this coalesce to form ____ which coarse downward around the infundibulum and join an extensive network of sinusoids w/in the pars distalis and forms ____.
-This arrangement constitutes the _____
-____ provide additional blood supply; anastomose to form an arterial ring around the pituitary and branches from this ring penetrate the ____.

Back 21

-paired arteries originating from the internal carotid arteries
-superior hypophyseal arteries
-hypothalamus
-primary capillary plexus; venules; secondary capillary plexus
-hypothalamo-hypophyseal portal system
-Inferior hypophyseal arteries; pars nervosa (and the pars distalis)

Front 22

What is the adenohypophysis composed of?

Back 22

cords of epithelioid cells located along sinusoidal capillaries

Front 23

What are the cell types of the adenohypophysis?

Back 23

chromophils (acidophils (40%)and basophils (10%))
chromophobes (50%)

Front 24

What do acidophils secrete?

Back 24

growth hormone (somatotropin) and prolactin

Front 25

What do basophils secrete?

Back 25

TSH, LH, FSH, and ACTH (glycoproteins)

Front 26

What are chromophobes?

Back 26

transiently degranulated chromophils

Front 27

What are the glial cells called in the neurohypophysis?

Back 27

pituicytes

Front 28

T/F No cells are synthesized w/in the cells of the pars nervosa?

Back 28

True

Front 29

Neuronal (axonal) processes from cell bodies located in the hypothalamus travel through the infundibular stalk and terminate where?

Back 29

on fenestrated capillaries iin the pars nervosa where hormones are stored

Front 30

Where are ADH and Oxytocin produced?

Back 30

in the supraoptic and paraventricular nuclei of the hypothalamus

Front 31

What hormones are octapeptides bound to carrier glycoproteins (neurophysins)?

Back 31

ADH and oxytocin

Front 32

What are the secretory endings and secretory granules of ADH and oxytocin referred to as?

Back 32

Herring bodies

Front 33

What promotes fluid resorption by renal tubules and controls blood pressure?

Back 33

ADH

Front 34

What are the principal targets of ADH?

Back 34

collecting ducts of the kidney and the smooth muscle of peripheral arterioles

Front 35

T/F Increased ADH secretion results in large volume of dilute urine (diabetes insipidus)

Back 35

F- Reduced ADH

Front 36

What stimulates mammary gland myoepithelial cells for the ejection of milk from the breast during lactation and stimulates smooth muscle contraction of the pregnant uterus?

Back 36

oxytocin

Front 37

What is the most common form of pituitary tumor (usually benign but can be life threatening if untreated by either surgery or medication)?

Back 37

pituitary adenomas such as prolactinomas

Front 38

The thyroid gland has a right and left conical shaped lobes connected across the midline by the what?

Back 38

isthmus

Front 39

What is the blood supply for the thyroid gland?

Back 39

superior and inferior thyroid arteries

Front 40

The thyroid gland is surrounded by a CT capsule:
-External capsule blends in w/ visceral and pretracheal layers of ____
-Internal capsule penetrates the gland and divides it incompletely into ___

Back 40

-deep cervical fascia
-lobules

Front 41

How are secretory cells of the thyroid gland arranged?

Back 41

into spheres, or follicles

Front 42

What seperates the follicles of the thyroid gland?

Back 42

loose and highly vascular CT

Front 43

What type of epithelium does the thyroid gland have?

Back 43

follicular epithelium- usually simple cuboidal cells (all cells of a given follicle are similar in character and their hight varies according to the functional state of the follicle)

Front 44

Active follicles generally have (high/low) epithelium.
Inactive follicles generally have (high/low) epithelium.

Back 44

high
low

Front 45

Follicular epithelial cells
-rest on a ___, which seperates them from the periavascular spaces
-bear ___ on their free, apical surface
-are joined to adjacent follicular cells by ____
-extensive ____ ER (for the synthesis of thyroglobulin)

Back 45

-continuous basement membrane
-short microvilli
-junctional complexes
-rough

Front 46

Follicular epithleial cells
-____ is extensive in active cells
-____ abundant in cytoplasm (for breakdown of thyroglobulin)
-Produce ____
-____ is located in the extracellular space of the follicle; composed mosty of ____ , the inactive storage form of thyroid hormone.

Back 46

-golgi apparatus
-lysosomes
-thyroid hormone (thyroxine T4 and T3)
-colloid; thyroglobulin

Front 47

During the synthesis and release of of thyroid hormones, what is incorporated into thyroglobulin in rER and what is added to thyroglobulin in golgi apparatus?

Back 47

amino acids
polysaccharides

Front 48

During the synthesis and release of thyriod hormones, a ___ transports iodide through follicular cells, into the lumen of the follicle where it is oxidized into ___ by _____ in the cytoplasm of the follicular cells.

Back 48

-Iodide pump
-Iodine
-peroxisomes

Front 49

During the synthesis and release of thyroid hormones, what are iodinated in the follicular lumen (extracellularly)?

Back 49

tyrosine residues of thyroglobulin

Front 50

Where is TSH released from ?

Back 50

anterior pituitary

Front 51

In response to TSH:
-Follicular cells ___ from the colloid (receptor-mediated endocytosis)
-stimulates ___ synthesis
-____ fuse w/ colloid droplets and hydrolyze throglobulin into ____
-____ are released across basal membrane into the bloodstream (T4:T3 ratio of ___)

Back 51

-take up thyroglobulin
-Thyroglobulin
-lysosomes
-amino acids and carbohydrates
-thyroid hormones
-20:1

Front 52

What increases the basal metabolic rate of cells and stimulating carbohydrate, lipid, and protein metabolism?

Back 52

thyroid hormones

Front 53

What modulates the activity of sodium and other ion pumps of the plasma membrane regulating the entry of metabolites into cells?

Back 53

thyroid hormones

Front 54

Where are parafollicular cells (C cells) located?

Back 54

usually in the follicular walls w/in confines of the follicular basement lamina

Front 55

Parafollicular cells (C cells) are excluded from contact w/ the follicular lumen by ___ from adjoining follicular epithelial cells.

Back 55

cytoplasmic extensions

Front 56

Parafollicular cells may also occur in clusters where?

Back 56

in the interfollicular spaces

Front 57

What is the primal origin of the parafollicular cells thought to be?

Back 57

the neural crest

Front 58

How can parafollicular cells (C cells) be identified?

Back 58

by lead hematoxylin histochemistry

Front 59

What do parafollicular cells (C cells) secrete in response to high calcium levels in the blood?

Back 59

calcitonin

Front 60

What does the calcitonin released by the parafollicular cells do?

Back 60

inhibits osteoclast activity
lowers calcium levels in the blood
antagonistic to PTH

Front 61

What is usually four small glands located near the poles of the thyroid gland on its posterior aspect?

Back 61

parathyroid gland

Front 62

The parathyroid gland usually lie the what?
Where are the vessels and nerves derived from that supply the parathyroid gland?

Back 62

-thyroid capsule
-those supplying the thyroid gland

Front 63

Each gland of the ____ possesses a thin, intrinsic capsule of CT that seperates it from adjoining thyroid gland.

Back 63

parathyroid glands

Front 64

What are the parathyroid gland cells?

Back 64

Principal (chief) cells
Oxyphil cells

Front 65

Which parathyroid gland cell has a slightly eosinophilic cytoplasm containing lipofuscin granules and moderate amounts and glycogen and has a central dark vesicular nucleus?

Back 65

Principal (chief) cells

Front 66

What do chief cells produce and what does it do?

Back 66

parathyroid hormone (PTH) which acts to elevate serum calcium levels

Front 67

What does release of parathyroid hormone result in?

Back 67

Increases calcium absorption in intestine
Increases calcium reabsorption in kidney
Increases osteoclast activity (antogonistic to calcitonin)

Front 68

Oxyphil cells are (smaller/larger) than chief cells, and their cytoplasm is very (basophilic/eosinophilic)?

Back 68

-larger
-eosinophilic

Front 69

What parathyroid gland cell appears at puberty, increases in number w/ age, occurs singly and in clumps, and has an unknown function but may secrete PTH?

Back 69

oxyphil cells

Front 70

T/F Number of white fat cells decrease w/ age in parathyroid gland.

Back 70

False- increase

Front 71

What are the paired glands called that overlye the kidneys within renal fascia?

Back 71

adrenal (suprarenal) gland

Front 72

Which adrenal gland is roughly triangular and which is crescentic?

Back 72

triangular- right gland
crescentic- left gland

Front 73

What is the blood supply of the adrenal glands?

Back 73

Three suprarenal arteries derived from branches of inferior phrenic artery, abdominal aorta, and renal arteries

Front 74

The adrenal medulla has a dual blood supply, indirectly via the ____ and directly via the ___.

Back 74

-cortical sinusoids
-cortical arteries

Front 75

The adrenals recieve three sets of arteries, all of which contribute to what?

Back 75

subcapsular arterial plexus

Front 76

What arises from the subcapsular arterial plexus of the adrenal glands?

Back 76

-Subcapsular plexus- supplies the capsule
-Fenestrated sinusoidal capillaries- supply adrenal cortex before draining into the venous sinusoids of the medulla
-Medullary arteries- long arteries that pass unbranched to the medulla to form networks of medullary capillaries

Front 77

What is the venous drainage of the adrenal gland?

Back 77

small medullary veins coalesce to form the large central adrenomedullary vein

Front 78

What gland is surrounded by a thick dense, fibroelastic capsule of CT?

Back 78

adrenal

Front 79

What is the adrenal gland divided into and what do these divisions secrete?

Back 79

cortex-steroid secreting
medulla-catecholamine secreting

Front 80

What part of the adrenal gland has large lipid droplets, numerous mitochondria, and extensive smooth ER?

Back 80

Adrenal cortex

Front 81

What are the 3 zones starting from the most peripheral one to the innermost one that the Adrenal cortex is divided into?

Back 81

Zona glomerulosa
Zona fasciculata
Zona reticularis

Front 82

What does Zona glomerulosa produce?

Back 82

mineralocorticoids (aldosterone) in response to angiotension

Front 83

What is synthesized in response to angiotensin, increases water and sodium reabsorption in kidney, and leads to an increase in blood volume and pressure?

Back 83

mineralocorticoids (aldosterone)

Front 84

What is Zona fasciculata composed of and how is it arranged?

Back 84

composed of lipid droplet laden cells arranged in radial columns separated from each other by capillaries

Front 85

What does the Zona fasciculata produce and secrete?

Back 85

produces glucocorticoids (cortisol) and secretes some androgens

Front 86

Which portion of the adrenal cortex is under control of ACTH scretion from andenohypophysis?

Back 86

Zona fasciculata

Front 87

What increases metabolic availability of glucose and fatty acids to cells and depresses inflamatory response and immune response (inhibits wound healing)?

Back 87

cortisol

Front 88

Where is zona reticularis found?

Back 88

bw the fasciculata and medulla

Front 89

How are the cells of the Zona reticularis arranged and what does this zone produce?

Back 89

-cells organized in a loose meshwork configuration
-produces weak androgens (DHEA) and some glucocorticoids

Front 90

What is the adrenal medulla derived from and what surrouns it?

Back 90

-neural crest
-the three zones of cortex

Front 91

What are the principal cells of the adrenal medulla and how are they arranged?

Back 91

-chromaffin cells
-in cords closely investing the medullary sinusoids into which they secrete

Front 92

What does the chromaffin cells of the adrenal medulla produce?

Back 92

20% produce norepi and 80% produce epinephrine

Front 93

What enzyme converts norepinephrine to epinephrine and what up regulates it increaseing the amount of epinephrine released?

Back 93

-PNMT (phynylalanine N-methyl transferase
-Glucocorticoids

Front 94

Release of norepi and epi is under control of the sympathetic or parasympathetic nervous system?

Back 94

sympathetic

Front 95

What can be thought of as modified post-ganglionic sympathetic neurons that lack dendrites and axons?

Back 95

chromaffin cells

Front 96

What is chromaffin cell secretion regulated by?

Back 96

sympathetic nerves (acetylcholine)

Front 97

What is considered the exocrine and endocrine portions of the pancreas?

Back 97

exocrine- pancreatic acinar cells
endocrine- Islets of Langerhans

Front 98

Which portion of the pancreas has spherical masses of cells and is highly vascularized?

Back 98

endocrine

Front 99

What are the pancreas endocrine cells?
Can they be readily distinguished?

Back 99

Alpha cells, Beta cells, Delta cells
No

Front 100

Where are the alpha cells of the endocrine portion of the pancreas located and what do they secrete?

Back 100

-periphery of the islet
-glucagon-stimulates glucose synthesis and release (glycogenolysis)

Front 101

Where are the beta cells of the endocrine portion of the pancreas located and what do they secrete?

Back 101

-throughout the islet
-insulin- increases transport of glucose into cells

Front 102

What promotes the storage of glucose in the liver, skeletal muscle and adipose tiddue and promotes the uptake of amino acids by skeletal muscle?

Back 102

insulin

Front 103

Where are the delta cells of the endocrine portion of the pancreas located and what do they secrete?

Back 103

-throughout the islet
-somatostatin- inhibits release of insulin and glucagon; suppresses islet alpha and beta cells

Front 104

Which endocrine pancreatic cell is few in number and irregularly shaped?

Back 104

delta cells

Front 105

Where does the pineal gland project from and how big is it?

Back 105

-roof of diencephalon
-3-5mm

Front 106

What kind of cells is the pineal gland composed of?

Back 106

pinealocytes and glial (interstitial) cells

Front 107

What accumulates w/ age in the pineal gland and is useful as a midline landmark tht can be displaced by a brain tumor?

Back 107

calcium deposits on carrier proteins (called corpora arenacea or "brain sand")

Front 108

What do pinealocytes secrete?

Back 108

malatonin

Front 109

Melatonin:
-produced no a ____ rhythm, with highest levels at (nighttime/daytime)
-has an ___ effect in animals
-(decreases/increases) pigmentation in animals
-may be involved in ___ in humans
-may entrain the ___ in humans

Back 109

-circadian; nighttime
-antigonadotrophic
-decreases
-onset of puberty
-biological clock (sleep rhythms)