The Adrenal Gland Flashcards
1
Q
- The zona glomerulosa secretes _
- The zona fasciculata secretes _
- The zona reticularis secretes _
- The adrenal medulla secretes _ and _ (which is the main product?)
A
- Mineralcorticoids (EX: Aldosterone)
- Glucocorticoids (Cortisol) and Androgens (to a lesser extent)
- Androgens and Glucocorticoids to a lesser extent
- Epi (main prod) and NE
2
Q
- The adrenal cortex is derived from _ germ layer
- The adrenal medulla consists of _ cells derived from what germ layer?
A
- Mesoderm
- Chromaffin (Neural Crest)
3
Q
- Cortisol exerts negative feedback on the hypothalamus (preventing _ release) and the anterior pituitary (preventing _ release)
A
- CRH, ACTH (from corticotroph cells)
4
Q
- What are the main stimuli of cortisol secretion?
- What are the main effects of cortisol on the following organs/systems:
- Immune
- Liver
- Muscle
- Adipose Tissue
A
- Stress (ex: exercise or psychological stress) and Circadian Rhythms (regulated by SCN)
- Suppresses Immune Response
- Gluconeogenesis in the liver
- Protein catabolism in muscle
- Lipolysis in adipose tissue
Overall goal is to increase glucose levels in the blood so the body has energy to fight/flee from stimulus
5
Q
- Cortisol is secreted in a _ manner
- Secretory rates are highest _ and lowest during _
A
- Circadian Rhythm/Pulsatile
- Early morning, late evening
6
Q
- How do exogenous glucocorticoids exert negative feedback?
A
- Exert negative feedback in the same way cortisol does
- Exogenous glucocorticoids inhibit CRH release from the hypothalamus and ACTH release from the anterior pituitary
7
Q
- What is the main stimulus for the secretion of aldosterone?
- Which cells/layer of the renal cortex are responsible for the production of aldosterone?
A
- Main stimuli
- Increased K+ or Decreased Na+ in blood
- Decreased blood volume and/or blood pressure
- Zona glomerulosa
8
Q
- What is the primary function of aldosterone?
- How does aldosterone accomplish this?
A
- Increase Na+ reabsorption and increase K+ excretion
- Transcription of the following transporters on the following membranes
- APICAL
- K+ channels
- eNAC channels
- BASOLATERAL
- Na+/K+ ATPase
- APICAL
9
Q
- Signs and Symptoms of Cushing’s Syndrome (Hypercortisolism)
A
- Truncal obesity
- Moon face
- Buffalo Hump
- Easy bruising
- Purple striae
- HTN
- Edema
- Weakness
- Osteoporosis
- Hirsutism
- Acne
- Virilization
- Diabetes
- Immunosuppression
- Cognitive Effects
10
Q
- How does the low dose dexamethasone suppression test work?
A
- Dexamethasone is an exogenous glucocorticoid
- Low dose test differentiates patients who have CS from patients who do not
- Upon administration of low dose, if patient:
- Does not have ACTH suppression, they are positive for CS (of some type)
11
Q
- How does the high dose dexamethasone suppression test work?
A
- Helps distinguish between types of Cushing’s Diseases (from pituitary or ectopic tumor)
- Patient given high dose of dexamethosone:
- Decrease in ACTH (pituitary tumor-mediated by negative feedback on pituitary)
- No Change in ACTH (ectopic tumor-no negative feedback effect)
12
Q
- What happens to CRH, ACTH, and Cortisol levels if a tumor in the adrenal gland is the underlying source for Cushing’s Disease?
- What happens to CRH, ACTH, and Cortisol levels if a tumor in the anterior pituitary is causing Cushing’s disease?
- What happens to CRH, ACTH, and Cortisol levels with an ectopic ACTH secreting tumor?
- What happens to CRH, ACTH and Cortisol levels with exogenous glucocorticoid drug administration (in excess)?
A
- Low CRH, Low ACTH, High Cortisol
- Low CRH, High ACTH, High Cortisol
- Low CRH, Low ACTH (from anterior pituitary) and high cortisol
- Low CRH, Low ACTH (exogenous glucocorticoids inhibit ACTH release from anterior pituitary), Low cortisol
13
Q
- Etiologies of Cushing’s Syndrome
A
14
Q
ACTH is derived from _ and is a peptide hormone
It is important because it helps with secretion of _ and synthesis of _ in non pituitary tissues
A
- POMC
- Alpha-MSH, melanin
15
Q
- Why does hyperpigmentation occur in Addison’s Disease?
A
- In Addison’s disease, there is lack of cortisol production, and hyperpigmentation results from increased ACTH levels that act as a result of feedback mechanisms in the HPA axis
16
Q
- How is cosyntropin (synthetic ACTH) stimulation test used to diagnose adrenal gland insufficiency (Addisons)
A
- Measure 8 am cortisol levels:
- If > 15, AI is ruled out
- If between 3-15, administer 30 min cortisol during cosyntropin stimulation test, and if >18, rule out AI, if < 18, can confirm AI and measure ACTH
- If <3 during 8 am cortisol levels, can confirm AI, measure ACTH
- Low or normal ACTH: Secondary or Tertiary AI (pituitary or thyroid)
- High ACTH: Primary AI (problem with adrenal glands themselves)
20
Q
- Identify how the levels of the following would change given the disease state
A
24
Q
- What is the rate limiting step in this reaction?
A
- Hormones (from top to bottom)
- ACh
- ACh
- Cortisol
- Enzyme (from top to bottom)
- Tyrosine hydroxylase
- Dopamine beta hydroxylase
- PNMT
Rate limiting step-Conversion of Tyrosine to Dopa via Tyrosine Kinase
25
Q
- NE is synthesized in the _ and E is synthesized in the _
A
- Nucleus, Cytosol
26
Q
- How are catecholamines degraded?
A
- COMT enzyme
- MOA
27
Q
- Catecholamine receptors:
- _ and _ receptors respond better to NE than Epi
- _ receptor responds equally to NE and E
- E is more potent than NE for _ receptor
A
alpha, beta 3
beta 1
beta 2
28
Q
- Major physiologic actions of NE and Epi (summary)
A
