Njds- Histology

Front 1

QUESTION What are three characteristics of endocrine glands?

Back 1

ANSWER
1) No ducts
2)Deposit hormones directly into bloodstream
3) Richly vascularized

Front 2

QUESTION What is the dual blood supply of the adrenal medulla?

Back 2

ANSWER
Arterial blood via the medullary arteries, and venuous blood via the cortical arteries.

Front 3

QUESTION
What is the blood supply of the adrenal glands?

Back 3

ANSWER
Arterial branches--> subcapsular plexus--> adrenal capsule--> cortical + medullary capillary beds

Front 4

QUESTION
What are the three layers of the adrenal cortex (outermost to innermost)?

Back 4

ANSWER
1)Zona glomerulosa
2)Zona fasciculata
3)Zona reticularis

Front 5

QUESTION
Characteristics of the zona glomerulosa

Back 5

ANSWER
Outermost layer of cortex, comprised of cords and clusters of columnar cells which produce mineralocorticoid hormones (mainly aldosterone) when stimulated by angiotensin II or ACTH.

Front 6

QUESTION
Characteristics of zona fasciculata

Back 6

ANSWER
Middle layer of adrenal cortex, large polyhedral cells which produce glucocorticoid hormones (cortisol and corticosterone) when stimulated by ACTH. Largest part of adrenal gland.

Front 7

QUESTIONS
What do cortisol and corticosterone do?

Back 7

ANSWER
-Anabolic and catabolic processes
-Help organism withstand stress
-Anti-inflammatory
-Immune supression

Front 8

QUESTION
Characteristics of zona reticularis

Back 8

ANSWER
Innermost layer of adrenal cortex, irregular darkly staining cells that produce androgens and small amounts of glucorticoids when stimulated by ACTH. Cells also contain lipofuscin pigment.

Front 9

QUESTION
True or False: Cells of the adrenal cortex store their products in secretory granules

Back 9

ANSWER
False, cells of the adrenal cortex release their products into the bloodstream upon stimulation

Front 10

QUESTION
What is the main cell of the adrenal medulla, and what does it secrete?

Back 10

ANSWER
Chromaffin cells (modified postganglionic secretory neurons) which secrete epinephrine and norepinephrine upon sympathetic stimulation

Front 11

QUESTION
What is the role of the thyroid gland?

Back 11

ANSWER
The thyroid gland plays a role in the stimulation of metabolism through the synthesis of thyroxine (T4) and triiodothyronine (T3)

Front 12

QUESTION
What is the most abused non-narcotic drug by physicians?

Back 12

ANSWER
Sinthroid (speeds up metabolism, keeps you up)

Front 13

QUESTION
What is colloid and what does it contain?

Back 13

ANSWER
Eosinophilic substance within the thyroid follicles, contains T3 and T4 bound to thyroglobulin.

Front 14

QUESTION
How does a follicular cell of the thyroid obtain thyroid hormone?

Back 14

ANSWER
When thyroid hormone is in demand, the follicular cell extends pseudopods into the surrounding colloid and brings the colloid into the cell.

Front 15

QUESTION
What are parafollicular (C) cells?

Back 15

ANSWER
Found between thyroid follicles, larger and paler than follicular cells, secrete CALCITONIN

Front 16

QUESTION
Describe the synthesis of thyroid hormones

Back 16

ANSWER
-Requires iodide and is regulated by TSH from the ant. pituitary
- Iodide is actively transported into follicular cell, where thyroid peroxidase in the cytoplasm oxidizes it.
- Oxidized iodide moves back into the colloid where it iodinates the tyrosine residues of thyroglobulin.
- Forms MIT and DIT
- MIT +DIT = T3
- DIT + DIT = T4

Front 17

QUESTION
Describe the release of thyroid hormones

Back 17

ANSWER
TSH--> basolateral membrane of follicular cell--> cytoplasmic extensions of apical membrane bring in some colloid (endocytosis)-->lysosome in FC breaks down components of colloid into MIT, DIT, T3, T4 --> T3 and T4 leave cell, MIT + DIT are broken down into iodine and tyrosine and recycled

Front 18

QUESTION
What are the functions of thyroid hormones?

Back 18

ANSWER
Thyroid hormones, in general, increase carbohydrate metabolism, fatty acid synthesis and vitamin uptake. They DECREASE cholesterol, phospholipid, and triglyceride synthesis.

Front 19

QUESTION
Describe the 2 cells found in the parathyroid glands, and what happens with age

Back 19

ANSWER
1)Chief cells: most numerous, cytoplasmic granules contain PTH

2)Oxyphil cells: larger than chief cells, with abundant mitochondria, unknown function

3) With age, parenchyma is gradually replaced by adipose tissue.

Front 20

QUESTION
What is the function of the parathyroid glands?

Back 20

ANSWER
Regulation of serum calcium levels through the actions of PTH

Front 21

QUESTION
How does PTH act on bone and kidneys?

Back 21

ANSWER
In bone: PTH stimulates osteoclast activity and number.

In kidneys: PTH makes cells of renal tubule resorb calcium and prevent resorption of phosphate. Also, PTH induces production of the active form of vitamin D, which enhances calcium reapsorbtion in intestine.

Front 22

QUESTION
What are the characteristics of the pituitary gland?

Back 22

ANSWER:
-Derived from both neural and oral ectoderm
-Produces and stores hormones for growth, metabolism, and reproduction
-Divided into anterior and posterior pituitary

Hint 22

pituary makes hormones from two different cells:

B-FLAT: basophils make FSH, LH, ACTH, and TSH

GPA: acidophils make prolactin, and growth hormone

Front 23

QUESTION
What are the 3 sections of the anterior pituitary (aka adenohypophysis) and what layer is it derived from?

Back 23

ANSWER
1) Anterior lobe (pars distalis)
2) Pars tuberalis
3) Pars intermedia

Anterior pituitary is derived from oral ectoderm (Rathke's pouch)

Front 24

QUESTION
What are the two components of the posterior pituitary and what layer is it derived from?

Back 24

ANSWER:
Composed of pars nervosa and the infundibulum (neural stalk), derived from neural ectoderm)

Front 25

QUESTION
What is the hypophyseal portal system?

Back 25

ANSWER:
Portal venous system is the only connection between the anterior and posterior pituitary. Portal system transports neurosecretory hormones from the hypothalamus -->ant. pituitary, where they modulate secretion of ant. pituitary hormones.

Front 26

QUESTION
What are somatotrophs? What releases and inhibits them?

Back 26

ANSWER
Acidophilic chromophil from the pars distalis, secretes GROWTH HORMONE, which increases metabolic rate and the growth of long bones.

Releasing hormone: SRH
Inhibiting hormone: Somatostatin

Front 27

QUESTION
Characteristics of mammotrophs

Back 27

ANSWER
Type of acidophilic chromophil from the pars distalis, secrete PROLACTIN, which is for development of mammary glands during pregnancy + milk secretion.

Releasing hormone: PRH
Inhib. hormone: PIH

Front 28

QUESTION
Characteristics of corticotrophs

Back 28

ANSWER
Basophilic chromophil from pars distalis, secrete ACTH which stimulates release of hormones from adrenal cortex

Releasing hormone: CRH

Front 29

QUESTION
Characteristics of thyrotrophs

Back 29

ANSWER
Basophilic chromophil in pars distalis, secrete TSH

Releasing hormone: TRH (thyrotropin releasing hormone)
Inhib. hormone: presence of serum T3 and T4

Front 30

QUESTION
Characteristics of gonadotrophs

Back 30

ANSWER
Basophilic chromophil in pars distalis. Secrete follicle stimulating hormone (FSH) and leutinizing hormone (LH)

Releasing hormone: GnRH
Inhib. hormone: serum estrogen, progesterone, and testosterone

Front 31

QUESTION
How do basophil hormones differ from acidophil hormones?

Back 31

ANSWER
Basophils differ from acidophils in that they have no specific inhibiting hormones (instead, basophils are inhibited by neg. feedback-- presence of substance released from target organs)

Front 32

QUESTION
What is the most common secretory cell type in the pars tuberalis of the ant. pituitary?

Back 32

ANSWER

Gonadotrophs

Front 33

QUESTION
What is secreted by the cells of the pars intermedia?

Back 33

ANSWER

Melanocyte stimulating hormone(MSH)

Front 34

QUESTION
What are Herring bodies?

Back 34

ANSWER
Neurosecretory granules accumulate in the pars nervosa and cause distension of the axon, forming pale basophilic Herring bodies.

Front 35

QUESTION
What is a pituicyte?

Back 35

ANSWER
Glial cell bordering the axon in the pars nervosa (posterior pituitary)

Front 36

QUESTION
What are the two hormones secreted from the posterior pituitary?

Back 36

ANSWER
1)ADH- increases water permeability in renal collecting tubules, concentrating urine.

2)Oxytocin: causes smooth muscle contraction in childbirth, and mammary gland milk ejection

Front 37

QUESTION
What governs the function of the pineal gland?

Back 37

ANSWER
Circadian rhythms

Front 38

QUESTION
What are 3 things found in the pineal gland?

Back 38

ANSWER
1)Pinealocytes which secrete melatonin and seratonin
2)Astrocyte-like interstitial cells
3) Corpora arenacea: concentric basophilic calcifications