The Adrenal gland 9/3/15 Flashcards Preview

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Flashcards in The Adrenal gland 9/3/15 Deck (41)
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1
Q

Where are the adrenal glands located?

A

One on top of each kidney

2
Q

What are the 2 portions of the adrenal gland?

A

Adrenal medulla = inner portion (part of sympathetic autonomic nervous system that controls fight for flight.

Adrenal cortex = outer portion, not part of nervous system. It secretes hormones in response to hormone stimulation.

3
Q

What does the adrenal medulla secrete?

A

Epinephrine and norepinephrine hormones

4
Q

What does the adrenal cortex secrete?

A

Steroid hormones

5
Q

What is the Adrenal Medulla derived from?

A

Neural crest cells

6
Q

What is the Adrenal cortex derived from?

A

Mesotheial cells

7
Q

____ is a modified sympathetic ganglion

A

Adrenal medulla
*No postsynaptic neurons with axons in it, instead the postganglionic cells release epinephrine (80%) and norepinephrine (20%) into the blood

8
Q

_____ converts norepinephrine (NE) to epinephrine (E).

A

Enzyme pheynl-N-methyltransferase

9
Q

Beta receptors have greater affinity for _____ and alpha receptors have greater affinity for _____>

A

Beta = E
Alpha = NE
*This means neural response to E and NE can vary.

10
Q

What is the response to E and NE in tissues not directly innervated by postganglionic neurons (liver, skeletal muscles and fat)?

A

E = acts to increase availability of metabolic fuel by stimulating lipolysis, glycogenolysis and gluconeogenesis.

11
Q

In short what does the adrenal medulla do?

A

Enhances the sympathetic response by releasing hormones that can reach additional target without neural circuits.

12
Q

Because the endocrine (hormone) signal is blood borne, the response is ________.

A

longer

13
Q

What are the zones of the Adrenal cortex?

A
Zona Glomerulosa = outermost
Zona Faciculata = middle
Zona Reticularis = innermost, adjacent to the medulla
*Each zone produces a different class of steroid.
14
Q

What are the 5 steroids secreted by the Adrenal cortex zones?

A
  1. Cortisol
  2. Corticosterone
  3. Aldosterone
  4. Anderostenedione
  5. Dehydroepiandrosterone (DHEA)
15
Q

In the adrenal cortex, steroid synthesis and secretion is stimulated by_______.

A

ACTH, Except for aldosterone which is regulated by other signals.

16
Q

Aldosterone is a ______ produced by cells in the _______.

A

Mineralocorticoid produced in Zona glomerulosa.

17
Q

What is the principal action of Aldosterone?

A

stimulate Na+ and H2O retention in the kidney in order to maintain blood volume and pressure.

18
Q

The mechanism by which aldosterone helps reabsorb Na+ and H2O in the kidney results in ________.

A

an increase of K+ and H+ in urine (Important!)

19
Q

How does aldosterone do its job?

A

The aldosterone-receptor complex binds to DNA and stimulates the synthesis of proteins that act to increase Na+ and H2O reabsorption from the tubular fluid back into the blood.

20
Q

What factors regulate the Secretion go aldosterone? (4)

A
  • Stimulated by increase in plasma K+
  • Stimulated by a decrease in plasma pH or Increase in Plasma H+
  • Stimulated by a drop in systemic blood pressure
  • Inhibited by increased Na+ intake
21
Q

Glucocorticoids _____ and ______ are secreted by the cells of the zone fasciculata.

A

Cortisol and corticosterone *Cortisol is the important one in humans.

22
Q

What are the major effects of Glucocorticoids (cortisol)?

A

To increase the availability of glucose: antagonizes the action of insulin.

  • increase gluconeogenesis in liver
  • Increase proteolysis in muscle
  • Increase lipolysis
  • decrease glucose uptake in muscle and fat
  • decrease immune and inflammatory responses
  • decrease growth and reproductive function
  • Permissive action on Beta receptors in vascular smooth muscle to regulate blood pressure.
23
Q

Synthesis and secretion of glucocorticoids is stimulated by _______.

A

ACTH

24
Q

Cortisol has a negative feed back action on ____ and ______.

A

CRH and ACTH

25
Q

__________ are secreted by the Zona Reticularis.

A

Sex hormones (androgens) DHEA and androstenedione.

26
Q

_____ Is the precursor of other sex steroids.

A

DHEA, so it can serve as a circulating reservoir for conservation in peripheral tissues containing steroidogenic enzymes

27
Q

Androstenedione is synthesized by ___________.

A

enzymatic conversion of DHEA.

28
Q

Which is a stronger androgen, DHEA or Androstenedione?

A

Androstenedione

29
Q

______ provides a nongonadal source of Testosterone and estradiol.

A

Androstenedione

30
Q

______ is important source so steroids prior to puberty and in postmenopausal women.

A

Androstenedione

31
Q

What are adrenal sex steroid important for?

A

Regulating:

  • mood
  • libido
  • hair growth
  • erythropoiesis
  • acne
32
Q

Synthesis and secretion of adrenal androgens is stimulated by _______.

A

ACTH

33
Q

What is the Stress response?

A

A response of the stress axis (Hypothalamus- ant. pituitary- adrenal cortex) to a stressor that stimulates hypothalamic CRH neurons and inputs to the SNS.

34
Q

What are the 3 primary goals of the stress response?

A
  1. maintain blood pressure
  2. mobilize and increase availability of metabolic fuel
  3. inhibit non-essential functions
35
Q

What shuts off the stress response?

A

Removal of stressor and negative feedback actions of cortisol on CRH and ACTH.

36
Q

What happens when cortisol is elevated for long periods and combined with chronic activation of SNS? 3 things..

A
  • Highly catabolic use of substrates to produce glucose. These tissues can be rebuilt after stress is over, but if it continues to long it can cause problems.
  • Cortisol inhibits inflammation, cytokines and phagocytosis, this conserves energy in the short term, but is damaging with chronic stress.
  • Mobilization of metabolic fuels increases lipids in the blood which can increase blood pressure ann cause hypertension
37
Q

What is Addison’s disease?

A
Adrenal insufficiency caused by:
PRIMARY insufficiency:
- disease
- Congenital disorder
- Autoimmune disorder 
SECONDARY insufficiency:
- pituitary problem
- Glucocorticoid therapy 
* This is important for dentist because patients may have complications with maintaining blood pressure during anesthesia.
38
Q

What are the Symptoms of Adrenal insufficiency?

A
  • low cortisol and high ACTH
  • weakness, lethargy and decreased appetite
  • low blood pressure
  • low glucose when fasting
  • hyper pigmentation due to lack of feedback control of POMC production
39
Q

How do you treat Adrenal insufficiency?

A

You don’t, you’re a dentist not a real doctor……….ha ha ha j/k you are supposed to treat with glucocorticoids and/or dietary control.

40
Q

What is Hypercortisolinemia/Cushing’s disease?

A

Typically caused by a pituitary tumor = excess cortisol.

41
Q

What are the symptoms of Cushing’s disease?

A
  • excessive tissue catabolism
  • diabetes like symptoms
  • impaired immune function
  • threat of hypertension
  • In dental patients the primary concern is impairment of immune function after a procedure, but hypertension, osteoporosis and increased bleeding are also a problem.