Histology of Endocrine Organs

Question 1

How does communication differ between the nervous system and endocrine system?

Answer 1

Nervous system - communication involves membrane depolarization and transmission of signal from synapses, rapid but short-lived.
Endocrine system - hormones distributed via cardiovascular system to bind to receptors on target cells, slower but longer-lasting

Question 2

What are the three main methods of controlling hormonal release?

Answer 2

Humoral stimuli- levels of ions monitored in blood/body fluids
Neuronal stimuli- nerve signals
Hormonal stimuli- hormone in bloodstream

Question 3

What are the direct targets of hypothalamic hormones?

Answer 3

Anterior pituitary, kidney/uterus (by releasing ADH and Oxytocin from Post. Pituitary), and adrenal medulla

Question 4

What are tropic hormones?

Answer 4

Hormones released from the hypothalamus that target the anterior pituitary in order to stimulate/inhibit it to release other hormones

Question 5

What is another name for the anterior pituitary? Posterior pituitary?

Answer 5

Anterior - adenohypophysis

Posterior - neurohypophysis

Question 6

What is the pars distalis, pars nervosa, pars tubaralis, pars intermedia, and cyst intermedia?

Answer 6

Pars distalis - cell bodies in anterior pituitary
Pars nervosa - axons/glial cells in posterior pituitary
Pars tuberalis - upper part of anterior pituitary
Pars intermedia - between pars distalis and pars nervosa, unknown function
Cyst intermedia - remnant of lumen of Rathke’s pouch

Question 7

What are the major cell types in the anterior pituitary and what do they secrete?

Answer 7

Somatotropic cells - GH
Thyrotropic cells - TSH
Corticotropic cells - ACTH, MSH
Gonadotropic cells - LH, FSH
Mammotropic cells - prolactin

Question 8

What is the blood supply to the hypophysis?

Answer 8

Hypothalamo-hypophyseal portal system

Question 9

What is the pineal gland?

Answer 9

Out-pocketing of diencephalon covered in pia mater, synthesizes melatonin and serotonin

Question 10

What is the microscopic anatomy of the thyroid gland?

Answer 10

Follicles made up of a layer of follicular cells that surround a fluid called the colloid. Colloid contains stored thyroglobulin
-it’s the only damn gland to store hormones OUTSIDE the cell

Question 11

What are parafollicular cells?

Answer 11

Lie outside of follicles in thyroid, secrete calcitonin when blood levels of calcium are high

Question 12

How does calcitonin lower blood levels of calcium?

Answer 12

Stimulates calcium secretion by kidneys, decreases calcium-releasing activity of osteoclasts, increases osteogenesis by osteoblasts

Question 13

What causes Grave’s disease?

Answer 13

Abnormal antibodies that stimulate TSH receptors causing over-secretion of T3 and T4. (Excess T3/T4 causes TSH levels to decrease)

Question 14

What is hypothyroidism?

Answer 14

Insufficient T3 and T4 production, often due to autoimmune disease attacking follicle cells

Question 15

What is a goiter?

Answer 15

Thyroid enlargement due to iodine deficiency (overproduction of thyroglobulin that cannot be iodinated)
Can also be due to hyperthyroidism (increased activity of thyroid gland causes enlargement) or hypothyroidism (unrelenting stimulation of thyroid gland by TSH)

Question 16

What is parathyroid hormone?

Answer 16

Comes from parathyroid glands (usually 2 pairs on posterior thyroid), regulates serum calcium and phosphate levels

Question 17

What are chief cells and oxyphil cells in the parathyroid glands?

Answer 17

Chief (principle) cells release PTH when [blood calcium] falls below 9.5 mg/dL
Oxyphil cells unknown function

Question 18

How does PTH work to increase blood calcium levels?

Answer 18

Stimulates osteoclasts to resorb bone and release calcium stores
Increases calcium retention by kidneys in the distal tubule
Stimulates kidney to convert inactive vit D to calcitriol (active vit D)
Calcitriol increase calcium absorption by intestine

Question 19

What are the layers of the adrenal gland?

Answer 19

Capsule
Zona glomerulosa (Salt)
Zona fasciculata (Sugar)
Zona reticularis (Sex)
Adrenal medulla

Question 20

What does the zona glomerulosa release?

Answer 20

Aldosterone (Salt)

Question 21

What does the zona fasciculata release?

Answer 21

Cortisol (Sugar)

Question 22

What does the zona reticularis release?

Answer 22

Androgens (and cortisol) (Sex)

Question 23

What does the adrenal medulla release?

Answer 23

Epi and norepi (chromaffin cells)

Question 24

What is Addison’s disease?

Answer 24

Hyposecretory disorder of both glucocorticoids and mineralocorticoids (autoimmune or deficiencies in hormone-producing enzymes). BGL and Na+ levels drop. Causes dehydration, low BP, fatigue, loss appetite

Question 25

What is Cushing’s syndrome?

Answer 25

Hypersecretion of glucocorticoids due to either ACTH-secreting pituitary tumor or tumor in adrenal cortex. High BGL, protein loss in muscles, muscle weakness, lethargy

Question 26

Describe pancreas histology

Answer 26

Mostly exocrine cells (pancreatic acini) containing clusters of endocrine cells (islets of Langerhans)

Question 27

What are the main cells of the pancreas and what do they secrete?

Answer 27

Alpha - glucagon
Beta - insulin
Delta - somatostatin (slows release of insulin/glucagon) =the controling DaD aka: Ben
F-cells - pancreatic polypeptide (inhibits release of somatostatin) Fuck Ben

you’re welcome for this analogy

Question 28

What is the pancreatic blood supply?

Answer 28

Insuloacinar portal system (islets of Langerhans) and acinar vascular system (pancreatic acini)

Question 29

What does the Ectodermal placode lead to at about the 3rd developmental week?

Answer 29

Rathke’s pouch

-moves to its final location around the 8th week

Question 30

In Pars Distalis: Which of the cells are Acidphils, which are basophis? and What are the red dot collections (openings) on the histo slide?

Answer 30

Acidphils: Pro athletes take GH and Acid
-Prolaction (mammotrophs) and GH (Somatotrophs)

Basophils: the others ACTH (cortico), TSH (thyro), FSH/LH (Gonado)

The openings are Sinusoidal (fenestrated capillaries) and they increase permeability

Question 31

What is stored in the Pars nervosa?

Answer 31

Post-Pituitary, so it houses ADH/Oxytocin in its Herring bodies