Histology 21: Endocrine Organs

Front 1

What is a paracrine hormone?

Back 1

hormone acts on an adjacent cells via interstitial fluid

Front 2

What is an autocrine hormone?

Back 2

cell releases a hormone that acts on itself (the same cell)

Front 3

3 major classes of hormones

Back 3

peptides, steroids, amino acid/arachidonic acid derivatives

Front 4

What class of hormones require transporters in the blood?

Back 4

steroid hormones and thyroid hormones

Front 5

Insulin uses what type of receptor?

Back 5

tyrosine kinase

Front 6

What do cAMP, DAG, IP3, and Calcium have in common?

Back 6

they are all second messengers in receptor mediated reactions

Front 7

G-protein receptors are commonly found where?

Back 7

on the cell surface (plasma membrane)

Front 8

What type of receptors do steroid and thyroid hormones use?

Back 8

intracellular receptors (to regulate gene transcription via HRE)

Front 9

Most hormones use what type of feedback system?

Back 9

negative

Front 10

If there are low levels of T3/T4 in a normal person, what will happen to TRH levels?

Back 10

increase due to loss of negative feedback

Front 11

3 parts of the anterior pituitary

Back 11

pars distalis, intermedia, tuberalis

Front 12

2 parts of the posterior pituitary

Back 12

infundibulum, pars nervosa

Front 13

What part of the posterior pituitary contains the median eminence?

Back 13

infundibulum

Front 14

Anterior pituitary is derived from ...

Back 14

oral ectoderm (Rathke's Pouch)

Front 15

Posterior pituitary is derived from ...

Back 15

neuro-ectoderm (floor of 3rd ventricle)

Front 16

Blood supply to the pituitary gland

Back 16

superior and inferior hypophyseal arteries (from internal carotid)

Front 17

What type of capillaries are found in the hypophyseal portal system?

Back 17

fenestrated capillaries

Front 18

Thyroid hormones exert negative feedback on what 2 hormones?

Back 18

TRH (from hypothalamus) and TSH (from anterior pituitary)

Front 19

6 hormones from anterior pituitary

Back 19

GH, FSH, LH, TSH, ACTH, prolactin

Front 20

What are tropic hormones?

Back 20

hormones that regulate other hormones (ACTH, FSH, LH, TSH)

Front 21

5 cell types of the anterior pituitary (pars distalis)

Back 21

Somatotropes, corticotropes, thyrotropes, lactotropes, gonadotropes

Front 22

TRH from hypothalamus stimulates what 2 hormones from the anterior pituitary?

Back 22

TSH and prolactin

Front 23

How does the hypothalamus control prolactin secretion form the anterior pituitary?

Back 23

hypothalamus secretes dopamine to inhibit prolactin

Front 24

2 acidophilic cells of the anterior pituitary

Back 24

somatotropes and lactotropes

Front 25

3 basophilic cells of the anterior pituitary

Back 25

thyrotropes, gonadotropes, corticotropes

Front 26

Corticotropes produce what hormone?

Back 26

POMC, which is cleaved into ACTH and B-LPH

Front 27

What type of cells are found in the posterior pituitary?

Back 27

neurosecretory neuron axons with cell bodies in the hypothalamic nuclei (supraoptic and paraventricular). also pituicytes, fibroblasts, and mast cells

Front 28

Are the axons in the posterior pituitary myelinated?

Back 28

No

Front 29

ADH binds to what receptors in the urinary system?

Back 29

V2 receptors in DCT and collecting ducts

Front 30

Oxytocin leads to contraction of ...

Back 30

uterine smooth muscle and myoepithelial cells of the mammary gland

Front 31

A patient is urinating 20 L of urine each day. Administration of vasopressin does not resolve the issue. What is the diagnosis? What is occurring in this patient most likely?

Back 31

nephrogenic diabetes insipidus. mutation in the aquaporin gene or mutated V2 receptors

Front 32

A patient is excreting extremely concentrated urine. What type of drug may we want to give him?

Back 32

a V2 receptor antagonist (Conivaptan) will block the excess ADH seen in SIADH

Front 33

6 tropic hormones from the hypothalamus

Back 33

GnRH, GHRH, GHIH (somatostatin), PIH (dopamine), TRH, CRH. (tropic= regulates other hormones)

Front 34

A patient is having difficulty sleeping. Where might we expect a lesion in the brain?

Back 34

pineal gland makes melatonin to regulate circadian rhythm

Front 35

Melatonin has what effect on GnRH?

Back 35

melatonin inhibits GnRH = less FSH/LH

Front 36

Thyroid gland is derived from ...

Back 36

pharynx and thyroglossal duct

Front 37

2 cell types of the thyroid gland

Back 37

follicular and parafollicular cells

Front 38

Hormones made by the thyroid gland

Back 38

T2, T3, T4, Calcitonin

Front 39

Steps of thyroid hormone formation.

Back 39

1) Synthesis of thyroglobulin. 2) Colloid intake and oxidation of Iodine. 3) Iodination of thyroglobulin. 4) Coupling of MIT/DIT to form T3/T4. 5) Release of hormones into blood

Front 40

What is the NIS transporter?

Back 40

Na/Iodine ATP dependent co-transport pump to put them both into the cell

Front 41

What is pendrin?

Back 41

Cl/Iodine exchanger on the apical cell membrane. puts iodine out of the cell and into the follicular space (colloid)

Front 42

Once iodine has entered the colloid, what happens to it?

Back 42

TPO (thyroid peroxidase) oxidizes it and adds it to the thyroglobulin to form MIT/DIT units

Front 43

What is megalin?

Back 43

thryoglobulin receptor to put it back into the thyroid cell

Front 44

Describe the lysosomal pathway of thyroglobulin resorption.

Back 44

thyroglobulin is endocytosed and degraded by proteases, releasing T3/T4

Front 45

Which cells of the parathyroid gland make PTH?

Back 45

chief cells

Front 46

PTH function

Back 46

increase calcium and phosphate levels of the blood

Front 47

PTH uses what type of receptor?

Back 47

G-protein

Front 48

PTH has what effect on calcium excretion by the kidney?

Back 48

PTH conserves calcium by decreasing urine calcium content

Front 49

PTH has what effect on phosphate excretion by the kidney?

Back 49

increases phosphate excretion

Front 50

Adrenal cortex is derived from ...

Back 50

mesodermal mesenchyme

Front 51

Adrenal medulla is derived from ...

Back 51

neural crest

Front 52

3 zones of the adrenal cortex and the primary hormone that it makes

Back 52

glomerulosa (aldosterone), fasciculata (cortisol), reticularis (androgens)

Front 53

What are the cells in the adrenal medulla that make norepinephrine/epinephrine?

Back 53

chromaffin cells

Front 54

Adrenal medulla innervation

Back 54

pre-ganglionic sympathetics

Front 55

What is the function of the drug reserpine?

Back 55

prevents high catecholamine levels by preventing them from entering the vesicles that they will be released in

Front 56

Conversion of norepinephrine into epinephrine is stimulated by which hormone?

Back 56

cortisol

Front 57

Function of Angiotensin-Converting Enzyme

Back 57

convert angiotensin 1 into angiotensin 2

Front 58

Function of renin

Back 58

convert angiotensinogen into angiotensin 1

Front 59

What directly stimulates aldosterone release from the zona glomerulosa?

Back 59

angiotensin 2

Front 60

Cortisol has what effect on blood-glucose levels?

Back 60

increases (promotes gluconeogenesis and glycogen breakdown)

Front 61

Administration of high levels of CRH will lead to hypertrophy of what part of the adrenal gland?

Back 61

zona fasiculata (CRH > ACTH > Cortisol production). also reticularis has some response to this

Front 62

How does cholesterol move through the blood?

Back 62

in LDLs or VLDLs (or HDLs)