"Microscopic Anatomy Endocrine Mira Krendel" 3/16

Question 1

Endocrine glands consist mostly of what kind of tissue?

Answer 1

Epithelial tissue

Question 2

Endocrine cells are in close contact with capillaries. What kinds of capillaries facilitate the most communication for hormones?

Answer 2

Many capillaries/sinusoids in endocrine glands have irregular shape and are fenestrated.

Question 3

The prefix “adeno” means:

Answer 3

glandular

Question 4

What are 3 characteristics of cells that secrete protein/polypeptide hormones?

Answer 4

Cells that secrete protein/polypeptide hormones:

1. have abundant RER
2. have prominent golgi
3. Hormones are stored in secretory granules.

Question 5

What are 3 characteristics of steroid-producing cells?

Answer 5

Steroid-producing cells:

1. Have a central nucleus
2. Lipid droplets can be seen in the cytoplasm
3. Abundant smooth ER for cholesterol synthesis
4. Mitochondria can be sphere-shaped with tubular or vesicular cristae
   * *#4 is unique to steroid-producing cells.

Question 6

The anterior pituitary gland is derived from what embryonic origin?

Answer 6

The anterior pituitary gland is derived from the oral ectoderm.
The AP consists of epithelial cells.

Question 7

The posterior pituitary is derived from what embryonic origin?

Answer 7

The posterior pituitary is derived from the neuroectoderm. The PP consists of neurons and glia.

Question 8

What is the function of a Rathke’s cyst?

Answer 8

Rathke’s cysts are colloid-filled circled between the AP and the PP. They are left over from the development of the pituitary, and have no known function.

Question 9

Chromaphils of the AP consist of what cell types?

Answer 9

Chromaphils include Acidophils and Basophils.

Chromaphobes are either stem cells or degranulated chromaphils and do not pick up stain.

Question 10

Explain the acronym for the anterior pituitary “GPA”

Answer 10

Growth hormone (somatotrophs)
Prolactin (lactotrophs)
Acidophils

Question 11

What cell types stain as basophils in the AP?

Answer 11

Gonadotrophs - LH and FSH
Thyrotrophs - TSH
Corticotrophs - ACTH and beta-lipotropin

Question 12

Thyrotropin is also known as:

Answer 12

TSH, thyroid stimulating hormone

Question 13

Acidophils, basophils and chromophobes are best visualized using special stains such as:

Answer 13

Hematoxylin, phloxine and isomine blue

Question 14

What part (“pars”) of the AP is inactive?

Answer 14

The pars intermedia is largely inactive in adults and contains colloid-filled follicles and Rathke’s cysts.

Hormones are produced in the pars distalis and the pars tuberalis sections of the AP.

Question 15

What are Herring bodies?

Answer 15

Herring bodies are where peptide hormones, produced in the hypothalamic neurons, are stored after they are sent, via axons, to the PP.

PP stores ADH (vasopressin) and oxytocin.

Question 16

Glial cells of the PP are also known as:

Answer 16

pituicytes

Question 17

Disruption of the infundibulum of the pituitary gland, such as through trauma or neoplasm, causes lack of communication between the hypothalamus and the PP. What pathology can then ensue?

Answer 17

Diabetes insipidus from lack of ADH getting to the PP.

Question 18

The adrenal cortex has an epithelial origin, and its cells produce steroid hormones. What three zones are seen in the adrenal cortex?

Answer 18

The three zones of the adrenal cortex are:

1. Zona glomerulosa (furthest from medulla)
2. Zona fasiculata
3. Zona reticularis (closest to medulla)

Question 19

Why do cells of the zona fasciculata appear foamy?

Answer 19

The cells of the zona fasciculata appear foamy due to their participation in steroid hormone synthesis, and contain lipid droplets.

Cells of the other two adrenal cortex zones also make steroid hormones, but in general do not appear as foamy.

Question 20

Explain the study trick “Salt Sugar Sex” as it applies to the adrenal cortex.

Answer 20

1. Zona glomerulosa - makes mineralcorticoids such as aldosterone - “salt”
2. Zona fasciluata - makes glucocorticoids such as cortisol (with some androgen secretion) - “sugar”
3. Zona reticularis - makes glucocorticoids and androgens such as DHEA - “sex”

Reticularis cells appear the most irregularly organized.
Glomerulosa cells frequently appear in bundles.

Question 21

Why does silver or chromium stain cause the adrenal medulla to appear dark? How does the adrenal medulla appear in H&E staining?

Answer 21

The adrenal medulla appears dark because these stains react with the electron-dense secretory granules containing the catecholamines being produced in the cells, such as epi and norepi.

The adrenal medulla appears pale in H&E preparation.

Question 22

What will happen to the adrenal cortex of an animal that lacks or loses its pituitary gland?

Answer 22

The adrenal cortex will atrophy if it is not stimulated to produce hormones.

Question 23

What are the symptoms and possible causes of Cushing’s syndrome?

Answer 23

Symptoms of Cushing’s syndrome:

1. Weight gain
2. Hyperglycemia
3. Easy bruising

Some Potential Causes of Cushin’s Syndrome:

1. Adrenal tumor
2. Excess ACTH secretion by AP
3. Ectopic ACTH secretion

Question 24

What are the functions of the islets of Langherhans of the pancreas?

Answer 24

The islets of Langherhans are compount masses of endocrine tissue. They produce polypeptide hormones, and stain lighter than surrounding exocrine tissue. The cells, as to be expected with poly-peptide hormone-producing cells, contain secretory granules.

Question 25

What hormones are produced in the islets of Langherhans?

Answer 25

1. Glucagon - raises blood glucose level 2. Insulin - lowers blood glucose level 3. Somatostatin - inhibits GH secretion and other hormones, is both endocrine and paracrine 4. Pancreatic polypeptide - helps with digestion

Question 26

Basal metabolic rate Body growth and development Heat production These are all functions of what endocrine organ?

Answer 26

Thyroid gland

Question 27

What is the shape of follicular epithelial cells?

Answer 27

Squamous to low columnar, but mostly cuboidal

Question 28

Follicular cells produce:

Answer 28

Follicular cells produce thyroglobulin, which is iodinated in the colloid. Iodinated hormones are absorbed and processed by the follicular cells before release into the bloodstream.

Question 29

What is another name for C cells? What is their function?

Answer 29

C cells are also known as parafollicular cells. In H&E preparation, they appear pale, and are located between thyroid follicles. C cells produce calcitonin which inhibits bone resorption/promotes calcification. Calcitonin is fedback by serum calcium levels

Question 30

How does PTH increase blood calcium levels?

Answer 30

PTH increases blood calcium levels by: 1. promoting osteoclast activity 2. regulating calcium absorption by the intestines and kidneys 3. increasing vitamin D synthesis

Question 31

Where are oxyphil cells found?

Answer 31

Oxyphil cells are found in the parathyroid gland. They stain brightly acidiphilic, and have no known function, though they may produce small amounts of PTH. Chief cells are more abundant in the parathyroid gland

Question 32

Many nonendocrine organs perform endocrine functions. Name two.

Answer 32

Heart secretes ANP - regulation of BP and electrolyte balance Stomach/small intestine secrete enteric hormones - regulate digestive enzyme production, GI motility, modulation of growth hormone secretion Adipose tissue --Leptin - regulates apetite and metabolism --Adiponectin - regulates FA and glucose metabolism, modulates sensitivity to insulin --Secretes steroid hormones such as androgens and estrogens