Bsf Exam 4: Endocrine Histology Part 2

Front 1

Back 1

Front 2

Where are the adrenal glands located?
What are the shapes of the adrenal glands?

Back 2

-above kidneys
-right adrenal - pyramid shaped
-left adrenal - crescent shaped

Front 3

The outer adrenal (cortex/medulla) is derived from ______ and is the _____ secreting portion of the gland

The inner adrenal (cortex/medulla) is derived from ____ and is the _____ secreting portion of the gland

Back 3

-cortex - embryonic mesoderm - steroid secreting

-medulla - neural crest - catecholamine

Front 4

What are the 3 layers of the adrenal cortex?

Back 4

-Zona glomerulosa
-Zona fasciculata
-Zona reticularis

Front 5

Zoma glomerulosa secretes:

Back 5

Mineralocorticoid hormones - involved in fluid/electrolyte balance
-Aldosterone - major mineralcorticoid - stimulates Na resorption at the distal convoluted tubule and other locations (retain water)

Front 6

Zona fasciculata cells are called:

Back 6

-Spongiocytes - names of cells due to "spongy" cytoplasmic appearance caused by lipid droplets

Front 7

Zona fasciculata secrets:

Back 7

-Glucocorticoid hormones - cortisol and corticosterone (regulate carbohydrate metabolism - acts on liver, adipose tissue, fibroblasts and immune system)

Front 8

How is glucocorticoids of the zona fasciculata regulated?

Back 8

-feedback system of hypothalamus and hypophysis

Corticotropin releasing factor (CSF) released when low glucocorticoids --> CSF stimulat ACTH synthesis --> ACTH secreted by adenohypophysis --> ACTH essential for growth and maintenance of cells in zona fasciulata and stimulates glucocorticoid synthesis and increased flow of adrenal gland

Front 9

Zona reticularis secrets:

Back 9

-weak androgens which can be converted to testosterone and estrogen
-stiulates secondary sex characteristics for women (major androgen secretion for women and minor for men)

*** May be the a zone of cellular degeneration

Front 10

What are the differences in the histological appearances of the zona glomerulosa, fasiculata, and reticularis?

Back 10

-glomerulosa - small columnar in oval clusters; small dark nucleus and acidophilic cytoplasm
-fasciculata - stain lightly acidophilic and larger than glomerulosa (spongy)
-reticularis - smiliar to fasciculata but smaller and more irregular

Front 11

What are the cells located in the adrenal medulla?
These are modified _____

Back 11

-chromaffin cells
-modified sympathetic postganglionic neurons (from neural crest) that have lost axons and dendrites

Front 12

Chromaffin cells of adrenal medulla secretes:

Back 12

Catecholamines:
-norepinephrine - large, dense granules
-epinephrine - small, less dense granules

Front 13

What are chromogranins?

Back 13

-major component of granules of norepinephrine and epinephrine
-may be binding proteins for catcholamines

Front 14

What innervates chromaffin cells and how are they controlled?

Back 14

-innervated by preganglionic sympathetic neurons
-Ach release by neuron depolarizes the cell, leading to catecholamine release
-different innervations = norepinephrine:epinephrine release may vary

Front 15

Describe fight or flight response:

Back 15

increase secretion of catecholamines (mainly epinephrine) resulting in increased cardiac output, heart rate, blood flow through organs, alertness and liver glycogenolysis

Front 16

The arteries that supply the adrenal gland branches before entering the capsule. What are these three branches and what do they do?

Back 16

-Fenestrated sinusoidal capillaries - supply cortex
-Medullary sinusoidal capillaries - receive blood from cortical sinusoids
-Medullary arterioles - carry arterial blood directly to medullary sinusoidal capillaries

Front 17

What are the endocrine portion of the pancreas?

Back 17

Islets of Langerhans

Front 18

What are the three main cell types of the islets of Lnagerhans and what do they secrete?

What are the other 2 cells in the islet that comprises less than 1%?

Back 18

-alpha cells - glucagon (activates gluconeogenesis and glycogenolysis in liver)
-beta cells - insulin (uptake of glucose)
-gamma cells - somatostatin paracrine and endocrine functions (paracrine - inhibits hormone release of alpha and beta) (endocrine - reduces smooth muscle contraction in alimentary tract and gall bladder)

-G cells - produce gastrin (stimulates stomach parietal HCl production)
-PP cells (F cells) - produce pancreatic polypeptide (inhibitor of exocrine pancreas secretion)

Front 19

Control mechanism of insulin and glucagon secretions is also due to ______ and ____ innervations

Back 19

sympathetic and parasympathetic innervations of endocrine pancreas

Front 20

____ between cells of islets permits cell-to-cell communication

Back 20

Gap junctions

Front 21

The pineal gland develops from _____ and is a cone-shaped projection from the floor of the ______

Back 21

-neuroectoderm
-diencephalon

Front 22

What are synaptic ribbons?

Back 22

-dense tubular structures unique to pinealocytes (function unknown)

Front 23

What does pinealocytes secrete?

Back 23

Melatonin:
-circadian and seasonal rhythms (increase at night)
-scavenges free radicals during oxidative stress (protective mechanism for the CNS)

*production and release is under sympathetic nerves that innervate pinealocytes

Front 24

What are the two cell types of the pineal gland?

Back 24

-pinealocytes
-interstitial cells (astrocytes) - structurally comparable to supportive neuroglial cells

Front 25

What is brain sand?

Back 25

-calcium phosphate and bicarbonate concentrations in pineal gland (function unknown)
-they are x-ray opaque and are used for radiographic markers