Adrenal Glands - PBT3

A pair of glands sitting on TOP of the Kidneys

Adrenal Gland

90% of the Adrenal gland by weight; secretes steroid hormones

Outer Cortex

10% of the Adrenal gland by weight; secretes catecholamines (Epi and NE)

Inner Medulla

-Aldosterone

-Glucocorticoid

-Androgen

Steroid Hormones produced by the Adrenal Cortex

This is a type of mineralcorticosteroid

-Function: To retain sodium and water

(specifically acts on KIDNEY to retain Na+ and water and to excrete K+)

Aldosterone

Function: To maintain adequate glucose / energy levels

Glucocorticoid

This is a sex hormone produced by the Adrenal cortex; it is important in women b/c the ovaries stop producing the female sex hormone at some point

Androgen

A glucocorticoid produced by the Adrenal cortex in response to Stress

-INC energy availability and suppresses non-essential functions

Cortisol

-Metabolism (INC blood sugar levels via gluconeogenesis)

-Immune System (suppress inflammation)

-Cardiovascular System (INC HR and BP)

-Nervous System (INC alertness, affects mood + cognition)

Main Effects of Cortisol

Stress triggers Hypothalamus → Secrete CRH (corticotropin-releasing hormone) → CRH stimulates Anterior Pitutary → Secrete ACTH (adrenocroticotropic hormone) → ACTH stimulates Adrenal Cortex → Secrete Cortisol

Hypothalamic-Pituitary-Adrenal (HPA) Axis in Regulating Cortisol

What does Cortisol inhibit?

-CRH from Hypothalamus

-ACTH from Anterior Pituitary

A type of HYPERadrenalism; leads to overproduction of Cortisol by the Adrenal glands

(Typically due to Pituitary adenoma secreting excessive ACTH)

Cushing’s Disease

-Weight gain (particularly central obesity)

-Round “moon face”

-Easy bruising

-High BP, blood sugar

-Stretch marks

-Muscle weakness

-Mood changes

Symptoms of Cushing’s Disease

-Surgery to remove tumors

-Meds to block Cortisol production (i.e. Ketoconazole AKA Nizoral, Metyrapone AKA Metopirone)

Treatment of Cushing’s Disease

A type of HYPOadrenalism; leads to inadequate production of Cortisol (and Aldosterone)

(Caused by autoimmune destruction of the Adrenal Cortex)

Addison’s Disease

-Weight loss

-Fatigue

-Low BP

-Muscle weakness

-Skin darkening (hyperpigmentation)

-Salt craving

-Low blood sugar levels

Symptoms of Addison’s Disease

-Lifelong hormone replacement therapy w/ Glucocorticoids (e.g, Hydrocortisone)

-Often Mineralocorticoids also (e.g., Flurocortisone)

Treatment for Addison’s Disease

Hypokalemia and Muscle weakness

Excess Aldosterone →

Hyperkalemia and Cardiac toxicity

Lack of Aldosterone →

What triggers the Kidney to release Renin(enzyme)?

DEC in blood volume

What step gives us Angiotensin I?

Renin cleaving Angiotensinogen (large protein made by liver)

What gives us Angiotensin II?

Angiotensin I conversion via ACE

What induces Vasoconstriction and thereby stimulates Adrenal Cortex to produce Aldosterone?

Angiotensin II

-Enhances CO (INC HR and BP)

-INC blood glucose (via breakdown of glycogen in liver and muscles)

-INC focus and alertness

-INC O2 supply

-INC visual perception (dilate pupil)

Epi (Adrenaline) Effects

-Stronger effect on Vasoconstriction (INC BP ++)

-Greater role in INCing focus and mental alertness ++

NE (Noradrenaline) Effects

In the stress response, this has SLOWER onset but more SUSTAINED effect !!
**Ideal for prolonged stress where we need ongoing energy supply

Cortisol

In the stress response, RAPID onset but SHORT duration

**Ideal for QUICK boost of glucose in immediate fight or flight

Epinephrine

Cortisol’s Primary Takeaway/Focus

Produce new glucose via Gluconeogenesis and DEC glucose uptake by cells and tissues → Enduring steady supply for VITAL function

Epi’s Primary Takeaway/Focus

Rapidly releases existing glucose stores (from Glycogen breakdown) for that easy queasy QUICK burst of energy <3