Neuroendocrinology

Question 1

What part of the brain regulates hormonal activity in the body?

Answer 1

Hypothalamus

Question 2

The brain secretes hormones directly/indirectly (choose one) through the posterior pituitary gland.

Answer 2

Directly

Question 3

The brain secretes hormones directly/indirectly (choose one) through the anterior pituitary gland.

Answer 3

Indirectly

Question 4

The body responds to hormones by returning the body to homeostasis. Does this occur via positive or negative feedback?

Answer 4

Negative

Question 5

Where are neurotransmitters produced and where do they act?

Answer 5

Produced within neurons and released to act locally on neighboring cells

Question 6

Give an example of a neurotransmitter.

Answer 6

Acetylcholine

Question 7

What type of chemical messenger is produced within neurons and then released into blood to affect cells at a distant site?

Answer 7

Neurohormones

Question 8

Give 2 examples of neurohormones

Answer 8

ADH and oxytocin

Question 9

What type of chemical messengers are released into the blood by endocrine cells and travel to affect cells at a distant site?

Answer 9

Classic mechanism endocrine hormones

Question 10

Give 3 examples of classic mechanism endocrine hormones.

Answer 10

TSH, ACTH, insulin

Question 11

What type of chemical messenger is released by endocrine cells and have local effects on adjacent cells (paracrine) or on the original cell that secreted them (autocrine)?

Answer 11

Extended definition endocrine hormones

Question 12

Give 3 examples of extended definition endocrine hormones.

Answer 12

Pancreatic somatostatin, estrogen, testosterone

Question 13

What is the neural part of the central neuroendocrine system? What about the endocrine part?

Answer 13

Neural part = hypothalamus
Endocrine part = pituitary

Question 14

What are 2 ways the central neuroendocrine system can respond to the peripheral system?

Answer 14

Maintenance of every day homeostatic mechanisms or through neuroendocrine reflexes

Question 15

What type of hormones target other endocrine tissues and cause production or secretion of another hormone?

Answer 15

Tropic hormones

Question 16

Give 2 examples of non-tropic hormones

Answer 16

Oxytocin and ADH

Question 17

What are the 3 lobes of the pituitary gland?

Answer 17

Posterior, anterior, intermediate

Question 18

What type of tissue makes up the posterior pituitary?

Answer 18

Nervous tissue

Question 19

What type of tissue makes up the anterior and intermediate pituitary?

Answer 19

Glandular (endocrine)

Question 20

What are 2 other names for the posterior pituitary?

Answer 20

Neurohypophysis and pars nervosa

Question 21

What are 2 other names for the anterior pituitary?

Answer 21

Adenohypophysis and pars distalis

Question 22

What is the name of the major bulk of the anterior pituitary?

Answer 22

Pars distalis

Question 23

What is the name of the part of the anterior pituitary that wraps up around the infundibulum?

Answer 23

pars tuberalis

Question 24

How does the hypothalamus communicate with the anterior pituitary?

Answer 24

Through the hypophyseal portal system

Question 25

How does the hypothalamus communicate with the posterior pituitary?

Answer 25

Substances produced in hypothalamus travel down axons and are stored in posterior pituitary

Question 26

What are the 2 hormones responsible for regulating calcium and phosphorus?

Answer 26

Calcitriol (Vitamin D) and Parathyroid hormone (PTH)

Question 27

Active vitamin D is formed in what organ?

Answer 27

Kidneys

Question 28

What is required for the synthesis of calcitriol in the kidney?

Answer 28

PTH

Question 29

What effect does PTH have on serum calcium and phosphorus in the GI tract?

Answer 29

Indirectly stimulates absorption (increases serum Ca and P) via Calcitriol

Question 30

What effect does PTH have on serum calcium and phosphorus in bone?

Answer 30

Stimulates the release of both (increases serum Ca and P)

Question 31

What effect does PTH have on serum calcium and phosphorus in the kidney?

Answer 31

Stimulates reabsorption of calcium and inhibits phosphorus reabsorption (increases serum Ca, decreases serum P)

Question 32

What effect does Calcitriol have on the GI tract?

Answer 32

Stimulates Ca and P absorption (increases serum Ca and P)

Question 33

Is the effect of PTH stronger on the kidney or bone? What is the net result?

Answer 33

Stronger effects on kidney; will see decreased blood phosphorus levels

Question 34

What is PTH secretion regulated by?

Answer 34

Directly by serum calcium concentration

Question 35

Does decreased serum calcium stimulate or inhibit PTH secretion?

Answer 35

Stimulates it

Question 36

What is calcitriol formation regulated by?

Answer 36

Directly by PTH concentration and indirectly by serum calcium concentrations

Question 37

If PTH concentrations are decreased, will calcitriol formation be stimulated or inhibited?

Answer 37

Inhibited

Question 38

What effect does Calcitonin have on calcium concentration?

Answer 38

Decreases it in bone

Question 39

Give 3 functions of phosphorus

Answer 39

Maintains cell membrane structure (RBCs), acid-base balance, and energy transfer (as ATP)

Question 40

Give 3 functions of calcium

Answer 40

Transmission of nerve impulses, contraction of muscle fibers, and coagulation of clotting factors

Question 41

The hypothalamus secretes ___________ hormones via the blood capillary system to the anterior/posterior (choose one) pituitary and cause it to release either a _____________ or _________ hormone.

Answer 41

releasing hormones, anterior pituitary, stimulating, functional hormone

Question 42

What type of hormone does the anterior pituitary secrete in response to a hypothalamic releasing hormone that will stimulate a distant gland to secrete another hormone?

Answer 42

Stimulating hormone

Question 43

What type of hormone does the anterior pituitary secrete in response to a hypothalamic releasing hormone that will stimulate a direct effect on distant organ tissues?

Answer 43

Functional hormone

Question 44

What are 2 examples of hormones that are both stimulating and functional hormones?

Answer 44

Follicle stimulating hormone and luteinizing hormone

Question 45

What type of hormones are prolactin and growth hormone?

Answer 45

Functional hormones

Question 46

What 2 functional hormones are secreted by the posterior pituitary but synthesized by the hypothalamus?

Answer 46

Oxytocin and ADH

Question 47

What effects does ADH have on the kidneys and blood vessels?

Answer 47

Kidneys - stimulates water reabsorption Blood vessels - stimulates vasoconstriction

Question 48

What are the 3 stimuli for ADH secretion?

Answer 48

Increased ECF osmolarity (more solute than water), decreased blood volume, and decreased blood pressure

Question 49

What are the 3 inhibitory factors for ADH secretion?

Answer 49

Decreased ECF osmolarity (less solute than water), increased blood volume, and increased blood pressure

Question 50

In a normal patient, are thyroid glands palpable?

Answer 50

No

Question 51

Are the parathyroid glands involved in thyroid function?

Answer 51

No, they regulate calcium and phosphorus

Question 52

What is the name of the glycoprotein within the colloid of the thyroid gland that helps to couple iodine to tyrosine to make thyroid hormone?

Answer 52

Thyroglobulin

Question 53

What is necessary from the diet for the synthesis of thyroid hormones?

Answer 53

Iodine

Question 54

How is iodine actively transported from the extracellular fluid into the thyroid follicular cell?

Answer 54

By the sodium-iodine symporter (NIS)

Question 55

What enzyme is responsible for the iodination of tyrosine residues on thyroglobulin?

Answer 55

Thyroid peroxidase

Question 56

What are the names of the iodinated tyrosine residues, and do they have biologic activity?

Answer 56

Monoiodotyrosine (MIT) and diiodotyrosine (DIT); do not have biologic activity

Question 57

How is the thyroglobulin-thyroid hormone complex transported back into the follicle?

Answer 57

Via endocytosis

Question 58

Once the thyroglobulin-thyroid hormone complex is broken down into T3, T4, MIT, and DIT, where do they go from here?

Answer 58

Thyroid hormones are released into the capillary space to enter circulation; MIT and DIT are deiodinated to iodine and amino acids, which are recycled for further hormone synthesis

Question 59

What enzymes regulate the activity of thyroid hormones by removing iodine from T4 in the peripheral tissues (i.e. liver, heart, muscle, gut, and nerves) to make bioactive T3?

Answer 59

Deiodinases

Question 60

What is the most bioactive form of thyroid hormones?

Answer 60

T3

Question 61

What effect does thyroid hormone have on systemic vascular resistance?

Answer 61

Decreases it

Question 62

What are the 5 systemic effects of thyroid hormones?

Answer 62

Increase basal metabolic rate, promotes growth & maturation, perinatal CNS development, regulation of ANS, and temperature regulation

Question 63

What effect does thyroid hormone have on renal blood flow and GFR?

Answer 63

Increases it

Question 64

What effect does thyroid hormone have on heart rate and contractility?

Answer 64

Increases it

Question 65

What effect does thyroid hormone have on blood pressure?

Answer 65

Increases it

Question 66

Name 3 stimuli for the release of TRH from the hypothalamus.

Answer 66

Low thyroid hormones, cold, stress

Question 67

Thyroid follicular cells requires stimulation by what hormone to produce and secrete thyroid hormones?

Answer 67

TSH

Question 68

TSH is produced and released by what?

Answer 68

Pituitary gland

Question 69

When excess T3 and T4 reach the pituitary, it inhibits the secretion of what hormone?

Answer 69

TSH

Question 70

What is the name for thyroxine that is not protein bound and is less than 1% of circulating thyroxine?

Answer 70

Free T4

Question 71

What are the only types of thyroid hormones that can enter cells to produce a biologic effect or regulate pituitary TSH secretion?

Answer 71

Free or unbound thyroid hormone

Question 72

Where is thyroid hormone conjugated and excreted?

Answer 72

In the bile and urine as soluble glucuronides and sulfates

Question 73

Both T4 and T3 are produced by the thyroid gland, but where is most of T3 formed?

Answer 73

In peripheral tissues

Question 74

What are the 2 parts of the adrenal gland?

Answer 74

Cortex and medulla

Question 75

The medulla of the adrenal gland is an extension of the _________ system and secretes __________________, such as ___________________ and ___________________.

Answer 75

Nervous system, catecholamines, such as norepinephrine and epinephrine

Question 76

What 2 hormones are secreted by the cortex of the adrenal gland?

Answer 76

Cortisol and aldosterone

Question 77

What effect do catecholamines have on blood vessels?

Answer 77

Cause vasoconstriction to maintain BP

Question 78

What are 6 functions of cortisol? Do your best

Answer 78

Regulate macronutrient metabolism, Maintain GI structure and function, Stress adaptation, Maintain normal BP, Anti-inflammatory properties, and Immunosuppressive properties

Question 79

What are the functions of aldosterone?

Answer 79

Control extracellular sodium (and water) and potassium concentration

Question 80

What zone of the adrenal cortex secretes aldosterone?

Answer 80

Zona glomerulosa

Question 81

What zone of the adrenal cortex secretes cortisol?

Answer 81

Zona fasciculata

Question 82

Dehydrated or hypovolemic patients stimulates the secretion of what hormone?

Answer 82

Aldosterone

Question 83

Aldosterone stimulates sodium ____________, potassium ____________, and hydrogen ___________ in the kidneys.

Answer 83

Sodium reabsorption, potassium secretion, and hydrogen secretion.

Question 84

Why is cortisol considered a diabetogenic hormone?

Answer 84

It inhibits cellular uptake of glucose

Question 85

List the stimuli for aldosterone secretion in priority order.

Answer 85

Increased serum potassium, increased serum angiotensin II, and decreased ECF volume

Question 86

Describe the pathway that stimulates cortisol secretion by the adrenal cortex

Answer 86

Stressful event (trauma, surgery, pain, etc.) -> CRH release from hypothalamus -> ACTH secretion from anterior pituitary -> cortisol release from adrenal cortex

Question 87

RAAS System: Renin is released by the _____________ in response to increased/decreased (choose one) ECF volume.

Answer 87

kidneys, decreased

Question 88

RAAS System: What does renin convert angiotensinogen in the liver to?

Answer 88

Angiotensin I

Question 89

RAAS System: What enzyme converts angiotensin I to angiotensin II?

Answer 89

Angiotensin converting enzyme (ACE)

Question 90

RAAS System: Once angiotensin II is formed, what 3 effects does it have?

Answer 90

1.) Stimulates aldosterone secretion by adrenal cortex 2.) Directly stimulates sodium reabsorption by the kidneys 3.) Constricts efferent arterioles in kidneys -> decreases peritubular capillary hydrostatic pressure -> stimulates sodium reabsorption

Question 91

What affinity does epinephrine have for alpha vs. beta receptors?

Answer 91

Equal affinity for both

Question 92

What affinity does norepinephrine have for alpha vs. beta receptors?

Answer 92

Alpha > beta

Question 93

What effect does norepinephrine and epinephrine have on alpha receptors? Which is the more potent actor on blood vessels?

Answer 93

Both cause constriction of peripheral blood vessels; Norepinephrine more potent on blood vessels than epinephrine

Question 94

What effect does norepinephrine and epinephrine have on beta-1 receptors? Which is the more potent actor?

Answer 94

Both increase the rate and contractility of the heart; Epinephrine more potent actor on beta-1 receptors

Question 95

What effect does norepinephrine have on beta-2 receptors?

Answer 95

Minimal to no effect

Question 96

What effect does epinephrine have on beta-2 receptors?

Answer 96

Dilation of airways and some blood vessels (heart, skeletal muscle, and liver)

Question 97

What do catecholamines secreted by adrenal medulla cause stimulation of in liver and skeletal muscle?

Answer 97

Glycogenolysis