Endocrine Glands

Question 1

Hormones

Answer 1

signaling molecules that are released into the bloodstream and regulate a variety of physiologic functions and metabolic processes

• act long-distance
• distributed by circulation
• released into bloodstream or interstitial fluid

Question 2

Properties of endocrine glands (4)

Answer 2

1. most consist of epithelial tissue (some are derived from neural crest or neurons)
2. no ducts are present
3. highly vascular
4. hormones may be stored in intracellular secretory granules

Question 3

Hormones are divided in to these two categories (and name examples)

Answer 3

Membrane impermeable (hydrophilic): peptides and proteins, glycoproteins, modified aa’s (receptors are on cell surface - act through secondary messengers)

Membrane permeable: steroid and thyroid hormones (receptors are intracellular DNA binding proteins that affect transcription)

Question 4

Characteristics of cells producing protein hormones (4)

Answer 4

1. abundant rough ER
2. prominent golgi
3. hormones often stored in secretory granules

Question 5

Characteristics of cells producing steroid hormones (4)

Answer 5

1. centrally located nucleus
2. lipid droplets in cytoplasm
3. abundant smooth ER (for cholesterol synth)
4. spherical mitochondria with characteristic tubular or vesicular cristae

Question 6

Hypophysis embryonic origin and fun facts about the anterior and posterior pituitary

Answer 6

AP (adenohypophysis) is derived from oral ectoderm and consists of epithelial tissue
PP (neurohypophysis) is derived from neural ectoderm.

AP has three regions: pars tubercles, pars distills, and pars intermedia.
PP contains no secretory cells - it stores hormones produced in hypothalamus

Question 7

Cells of the anterior pituitary can be divided into two groups based on their staining in routine histological preparations

Answer 7

Chromophils and chromophobes

Question 8

Chromophils

Answer 8

Cells containing secretory granules that interact with the dyes: basophils and acidophils

Question 9

Chromophobes

Answer 9

Cells that do not contain brightly stained granules – includes stem/progenitor cells and cells that have released their granules or lost their granules during fixation

Question 10

__________ is a type of chromophil that produces two types of protein hormones: __________ and __________

Answer 10

Acidophils; Growth hormone and Prolactin (GPA)

Question 11

________ is a type of chromophil that produces glycoprotein hormones and small polypeptide hormones: name them

Answer 11

Basophils; FSH, LH, TSH; and polypeptide = ACTH and beta-LPH

B-FLAT

Question 12

Somatotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)

Answer 12

Acidophilic; 50%; somatotropin (aka GH); growth of long bones and other growth-related processes

Question 13

Lactotropic or mammotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)

Answer 13

Acidophilic; 15-20%; Prolactin; Stimulation of milk secretion

Question 14

Gonadotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)

Answer 14

Basophilic; 10%; FSH, LH (often produced by the same cell); FSH: stimulation of gametogenesis; LH: regulation of estrogen and androgen secretion; promotes ovulation in females

Question 15

Thyrotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)

Answer 15

Basophilic; 5%; Thyrotropin (TSH); stimulation of thyroid hormone secretion

Question 16

Corticotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)

Answer 16

Basophilic; 15-20%; ACTH and B-lipotropin; ACTH: stimulation of adrenal cortical hormone secretion; B-lipoprotein: promotes utilization of fat

Question 17

Each cell type in the AP secretes only one hormone type – name the two exceptions

Answer 17

Gonadotropic cells produce FSH and LH; Corticotropic cells produce ACTH and B-LPH

Question 18

Pars Intermedia

Answer 18

Largely inactive in adults and contains colloid-filled follicles and cysts (Rathke’s cysts) of unknown function

Question 19

Posterior pituitary contains two cell types: ______ and ______. Cell bodies of the neurons are located in the __________. The two hormones secreted are ____ and _____ and are stored in dilated eosinophilic axons called ______.

Answer 19

Neurons (their axons) and glial cells called pituicytes; hypothalamus; vasopressin (ADH) and oxytocin; Herring bodies

Question 20

Functions of the posterior pituitary hormones

Answer 20

Vasopressin/ADH: regulation of blood osmolarity, increases water reabsorption in kidney collecting ducts

Oxytocin: stimulation of uterine contraction during childbirth and contraction of myoepithelial cells of mammary glands during nursing

Question 21

Hypothalamus regulates the functions of the ________ via releasing and inhibiting hormones into the ____________.

Answer 21

Adenohypophysis; hypothalamo-hypophyseal portal system

Question 22

Adrenal cortex is of _______ origin, has 3 concentric zones (name them), and has typical features of steroid producing cells (name 4)

Answer 22

Epithelial; zona glomerulosa, zona fasciculate, zona reticularis

1. centrally located nucleus
2. acidophilic cytoplasm with lipid droplets
3. abundant smooth ER (for cholesterol synth)
4. spherical mitochondria with tubular cristae (contain enzymes involved in synthesis of steroid hormones from cholesterol)

Question 23

Adrenal medulla is of ____ origin, has electron-dense granules that react with ____ and _____ (and the cells are therefore called _____ or _____). It produces ________.

Answer 23

Neuronal; chromium and silver salts (chromaffin or argentaffin); catecholamines (epi and NE)

Question 24

Zona glomerulosa (morphology, cell appearance/staining type, hormone produced, physiologic activity, regulated by)

Answer 24

Rounded cords of cells; steroid producing cells (appear foamy – most in fasciculata); mineralcorticoids (aldosterone); regulation of salt balance; angiotensin II

Question 25

Zona fasciculate (morphology, cell appearance/staining type, hormone produced, physiologic activity, regulated by)

Answer 25

Long cords; steroid producing cells (appear foamy); glucocorticoids (primarily cortisol) some DHEA; regulation of glucose metabolism; ACTH

Question 26

Zona reticularis (morphology, cell appearance/staining type, hormone produced, physiologic activity, regulated by)

Answer 26

Irregular meshwork; steroid producing cells (appear foamy – most in fasciculata); cortisol and a weak androgen (DHEA); glucose regulation and testosterone production; ACTH

Question 27

Pancreas – Islets of Langerhans (morphology, cell appearance/staining type, hormone produced, presence/lack of secretory granules)

Answer 27

Polygonal or round cells arranged in cords; typical protein secreting cells (abundant RER and golgi), lightly stained (lighter than exocrine); produces polypeptide hormones (insulin, glucagon, somatostatin, pancreas polypeptide); presence

Question 28

Cell types and quantity/location of endocrine pancreas, what they secrete, and functions of the two least frequent type

Answer 28

Alpha = 20% (glucagon – found in periphery of islets)
beta = 80% (insulin – centrally located)
delta = 5-10% (somatostatin – inhibits release of other islet cell hormones (paracrine effects) and inhibits release of GH and TSH by the pituitary and HCl secretion by the gastric parietal cells
F or PP = rare – pancreatic polypeptide: stimulates activity of gastric chief cells, inhibits bile and pancreatic enzyme secretion

Question 29

Thyroid consists of follicles lined by _______ epithelium and filled with ______, which consists of the storage form of thyroid hormones, called _______.

Answer 29

Simple cuboidal to low columnar; colloid; thyroglobulin

Question 30

Follicular cells have features of _____ secreting cells (abundant RER and golgi). Its activity is regulated by _______. It produces _____, which regulate BMR, body growth and development and heat production.

Answer 30

Protein; TSH; Thyroid hormones (T3 and T4)

Question 31

Parafollicular cells (aka ______) are larger/smaller in size than follicular cells, appear _____ in H&E, are located within the basal lamina or between follicles, produce hormone _____ that ______ bone resorption and _____ calcification of bone (opposite of _______). Regulated by ______.

Answer 31

C cells; larger; pale; calcitonin; inhibits; promotes; PTH; blood calcium levels

Question 32

Parathyroid glands are made up of two types of cells ________ and _______.

Answer 32

Chief cells (more abundant) and oxyphil cells

Question 33

Chief cells (morphology, cell appearance/staining type, hormone produced, physiologic activity, regulated by)

Answer 33

Small polygonal; pale staining, slightly acidophilic cytoplasm; parathyroid hormones (polypeptide hormone); increases blood calcium by regulating osteoclast activity, kidney excretion of calcium, vitamin D synthesis, and intestinal absorption of calcium; calcium level in blood

Question 34

Oxyphil cells (morphology, cell appearance/staining type, hormone produced/function)

Answer 34

Large cells; highly acidophilic (oxyphilic); unknown function – may produce a small amount of PTH

Question 35

Hormone secretion by non endocrine organs (4)

Answer 35

Stomach and small intestine: enteric hormones
Kidney: erythropoietin, renin
Heart: atrial natriuretic peptide (regulation of BP and electrolyte balance)
Adipose tissue: leptin (regulates appetite and metabolism), adiponectin (regulates FA and glucose metabolism and modulates sensitivity to insulin); steroid hormones (androgens and estrogens)