Endocrine System

Question 1

Endocrine System - function and interactions

Answer 1

Regulates metabolic activities in certain organs and tissues
Produces slow and diffused effect via hormones
Interacts closely with nervous system

Question 2

Endocrine system consists of (3)

Answer 2

Endocrine cells - isolated in epithelial lining of digestive tract and in respiratory system
Distinct clusters of cells within certain organs of the body
Ductless, richly vascular glands

Question 3

Endocrine glands list (5)

Answer 3

Pituitary
Pancreas
Suprarenal
Thyroid
Parathyroid

Question 4

Pituitary gland aka hypophysis - function and location

Answer 4

Produces hormones responsible for regulating growth, reproduction and metabolism
Under hypothalamus, center of the brain by the brain stem

Question 5

Pituitary gland subdivides

Answer 5

Adenohypophysis (anterior)

Neurohypophysis (posterior)

Question 6

Adenohypophysis - anterior development

Answer 6

develops from evagination (Rathke’s pouch) of oral ectoderm, lines primitive oral cavity
Loses contact with oral ectoderm, becomes isolated

Question 7

Neurohypophysis - posterior development

Answer 7

develops from neural ectoderm as a down-growth of the diencephalon
Maintains attachment to oral ectoderm of the brain

Question 8

Regions of anterior pituitary adenohypophysis

Answer 8

Pars distalis (pars anterior)
Pars intermdia (little or none)
Pars tuberalis (stalk)

Question 9

Regions of posterior pituitary neurohypophysis

Answer 9

Median eminence (little or none)
Infundibulum (stalk)
Pars nervosa

Question 10

Pars nervosa (posterior pituitary)

Answer 10

Secretory endings with PAS positive granules can be visualized
Referred to as Herring bodies (little pink dots)
Secretes ADH and oxytocin

Question 11

Pars distalis (anterior pituitary) 2 types of secreting cells

Answer 11

Acidophils
Basophils
Very dark purple H&E stain

Question 12

Acidophils (pars distalis anterior pituitary)

Answer 12

Lactoropes - secrete prolactin

Somatotropes - secrete growth hormone

Question 13

Basophils (pars distalis anterior pituitary)

Answer 13

Thyrotropes - secrete thyroid-stimulating hormone (TSH)
Gonadotropes - secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
Corticotropes - secrete aderenocorticotropic hormone (ACTH)

Question 14

Pancreas (both endo/exocrine, but focus on endocrine) made up of ___

Answer 14

Islets of Langerhans

Question 15

Islets of Langerhans cells and hormones (3)

Answer 15

Alpha cells - glucagon (glucose release)
Beta cells - insulin (glucose uptake)
Delta cells - somatostatin (inhibitory hormone)

Question 16

Suprarenal (Adrenal) Gland

Answer 16

Surrounded by dense, fibroelastic capsule of conncetive tissue
Sits on top of the kidney

Question 17

Parenchyma of adrenal gland histological 2 regions

Answer 17

Suprarenal cortex

Suprarenal medulla

Question 18

Suprarenal cortex

Answer 18

Produces corticosteroids, synthesized from cholesterol

Question 19

Suprarenal medulla

Answer 19

Functionally related to and regulated by sympathetic nervous system
Produces E and NE

Question 20

Adrenal Cortex 3 zones

Answer 20

Zona glomerulosa - peripheral region contains ovoid configuration (outer cortex)
Zona fasciculata - middle zone composed of cells arranged in columns separated from each other by continuous column of capillaries (middle cortex)
Zona reticularis - between fasciculata and medulla, cells organized in loose meshwork configuration (inner cortex)

Question 21

Adrenal cortex hormones

Answer 21

Zona glomerulosa - aldosterone
Zona fasciculata - cortisol and/or corticosterone
Zona reticularis - androstenedione (male androgenic hormone)

Question 22

Thyroid Gland - location and structure

Answer 22

Bi-lobed located in superior mediastinum (neck)

Two layers of fibrous connective tissue surround gland and blend with fascia of the neck

Question 23

Thyroid gland - hormones

Answer 23

Secretes T4 and T3 (under control of TSH from anterior pituitary), stimulate rate of metabolism
Calcitonin, aids in decreasing blood Ca levels, facilitates storage of Ca in bone

Question 24

Thyroid follicles - producing, storing, taking back and releasing hormones

Answer 24

Secretory cells - follicular epithelial cells - arranged in hollow spheres (follicles) with loose, highly vascular connective tissue between them
Short macrovilli on apical surface
Outer ring of cuboidal epithelium surrounds colloid, which contains thyroglobulin bound with T3&T4
Released into center of the follicle, stored in a bound form and then released when thyroid hormone is needed
Takes in bound colloid, freezes T3&T4, released into bloodstream

Question 25

Parafollicular cells

Answer 25

Usually located in follicular walls
Large cells, stain heavily with lead H from H&E stain (very blue)
Produce calcitonin, which lowers serum calcium

Question 26

Parathyroid Glands - location and structure

Answer 26

4/5 glands located on posterior surface of the thyroid
Usually lie within capsule of thyroid gland
Each have a thin connective tissue capsule
Secretory cells arranged in cords and plates set in a loose stroma of connective tissue

Question 27

Parathyroid Gland hormone

Answer 27

produce PTH which elevates serum calcium while reducing serum potassium via stimulation of osteoclasts

Question 28

Parathyroid cell types

Answer 28

Principal (chief) cells - central, nucleus, slightly eosinophilic cytoplasm with glycogen and lipofuscin granules - produce PTH
Oxyphil cells - larger but less common than chief cells, very eosinophilic cytoplasm, believed to be inactive phase of chief cells

Question 29

Objectives

Location, basic function, cell types, secretions

Answer 29

Pituitary, pancreas, suprarenal, thyroid, parathyroid