Endocrine System

Question 1

Upregulation

Answer 1

increase in number of receptors on/within a cell, allows more hormone molecules to bind receptors on target tissues

occurs when hormone levels are low

Question 2

How long it takes for hormone regulation to occur in response…

Answer 2

hours to days

Question 3

Downregulation

Answer 3

decrease in number of receptors on/within a cell

occurs when hormone levels are high

Question 4

Negative feedback mechanisms

Answer 4

Maintains homeostasis

Endocrine tissue increases secretion of hormone in response to stimulus

Hormone circulates in blood to produce effects on target tissue

Hormone binds receptors on endocrine tissue which decrease secretion of hormone

Question 5

How Hormones are regulated by the hypothalamic pituitary axis (negative feedback system - hormonal)

Answer 5

Hypothalamus secretes hormone A into pituitary portal
Hormone A stimulates cells in pituitary gland to secrete hormone B into circulation

B-C etc.

Question 6

Example of Humoral Stimuli (negative feedback)

Answer 6

Pancreas secretes insulin and glucagon in response to levels of glucose in blood

Glucose levels are high = pancreas secretes insulin

Glucose levels are low = pancreas secretes glucagon

Question 7

Example of Neural Stimuli (negative feedback)

Answer 7

Adrenal medulla secretes epinephrine into blood

Adrenal medulla is stimulated to secrete epinephrine by the SNS during times of stress or activity

Question 8

Communication (hormone release cascade)

Answer 8

Hypothalamus –> pituitary gland –> endocrine gland –> tissues

Question 9

Lobes of pituitary gland

Answer 9

Anterior

Posterior

Question 10

Anterior pituitary gland hormones that are secreted

Answer 10

Growth hormone
Prolactin

Growth hormones

Question 11

Posterior pituitary gland hormones that are secreted

Answer 11

Antidiuretic hormone (water balance)
Oxytocin (promotes myometrial contraction during labor and delivery)

Question 12

Growth hormone

Answer 12

promotes growth and development of bones, cartilage, muscles, glands

breaks down adipose tissue for energy

carried out by insulin-like growth factors

Question 13

GH disorders

Answer 13

related to undersecretion and oversecretion

Question 14

GH disorders - undersecretion

Answer 14

Dwarfism (during childhood)
- GH replacement therapy is tx

In adulthood
- signs include reduced muscle mass, increased adipose tissue, insulin resistance etc.

Abuse
- used by athletes to increase muscle mass and reduce body fat

Question 15

GH drug for undersecretion

Answer 15

Somatropin

Question 16

GH disorders - oversecretion

Answer 16

Childhood
- gigantism (tx with surgery)

Adulthood
- acromegaly (enlarged facial bones) - GH receptor antagonists

Question 17

Deficiency pf ADH causes…

Answer 17

diabetes insipidus

• large volumes of dilute urine
• extreme thirst

Question 18

Excess ADH secretion causes…

Answer 18

Syndrome of inappropriate ADH (SIADH)

- fluid retention, concentrated urine, low serum osmolality, sodium loss in urine

Question 19

Diabetes Insipidus - signs

Answer 19

Thirst
Dilute urine
Dry skin, poor skin turgor
confusion

Question 20

What side effect might you see if a high dose of vasopressin is given and why?

Answer 20

HTN (vasopressin is a potent vasocontrictor)
Angina (risk for MI)
Increased risk for myocardial infarction
Excessive fluid retention

Question 21

What diagnostics would you include in your assessment while administering vasopressin?

Answer 21

Physical examination

Lab tests: renal function ( urine specific gravity, urine osmolarity, serum electrolytes)

Question 22

Hormones that are secreted by the thyroid gland

Answer 22

T3 (tri-iodothyronine)

T4 (thyroxine)

Question 23

T3/T4 help regulate

Answer 23

basal metabolic rate

• positive inotropic, chronotropic effects
• inc metabolism of nutrients
• inc body temp
• inc GI motility, appetite
• inc secretion of GH

Question 24

T3/T4 negative feedback mechanism

Answer 24

hypothalamus secretes TRH into pituitary portal vein (when T3/T4 is low)
TRH stimulate anterior pituitary to secrete TSH
TSH stimulates thyroid gland to secrete T3/T4
T3/T4 have inhibitory effect on hypothalamus and anterior pituitary

Question 25

T3 and T4

Answer 25

produced in the thyroid gland through the iodination and coupling of amino acid tyrosine

body needs 1 mg of iodine per week

Question 26

When administering levothyroxine, what symptoms may occur and why?

Answer 26

Increases metabolic rate
- increasing oxygen consumption, respiration, HR

Increases rate of fate, protein and carbohydrate metabolism

Question 27

Adrenal Gland is composed of…

Answer 27

Medulla

Cortex

Question 28

Adrenal Medulla Secretes

Answer 28

Epinephrine, NE

Question 29

Adrenal cortex secretes

Answer 29

Aldosterone
Hydrocortisone
estrogen, testosterone

Question 30

Mineralocorticoids (aldosterone)

Answer 30

Secreted with extracellular potassium is high

Secreted in response to angiotensin II
Conserves sodium and water during dehydration, regulates plasma volume

Question 31

Glucocorticoids (hydrocortisone)

Answer 31

secreted in response to ACTH (ACTH secreted by anterior pituitary in response to corticotropin releasing mechanism
levels change and vary during circadian rhythms, stress and inflammation

Question 32

Glucocorticoids (hydrocortisone)

Answer 32

increase BG levels
Increase catabolism of proteins and lipids
Suppress inflammatory response and immune responses
increase sensitivity of vascular SM - Increases HR and BP
Bronchodilation

Question 33

Gonadocorticoids (mostly androgens)

Answer 33

control onset of puberty

primary source of endogenous estrogen in postmenopausal women

Question 34

Ways in preventing adverse effects of corticosteroids

Answer 34

1. Lowest dose possible
2. Apply topically locally
3. Alternate day dosing to minimize adrenal atrophy

Question 35

Side effects of corticosteroid therapy

Answer 35

Suppression of immune and inflammatory response
Peptic ulcers (mucosal lining and then the gastric acids rise causing ulcers)
Osteoporosis (suppress bone formation, muscle wasting
Behavioral changes (talkative, insomnia)
Metabolic changes

Question 36

Crushings Syndrome

Answer 36

Causing high levels of corticosteroids over long period

results of pituitary or adrenal tumors
Can be result of long-term drug therapy systemic corticosteroids