The Endocrine System - Cortisol Lec 2 Part 1

The Adrenals and the Stress Response

The Adrenal Gland Hormones → Adrenal Medulla

• Innermost region produces hydrophilic hormones

  • Catecholamine (epinephrine)

• Part of Sympathetic signaling → Fight-or-Flight

The Adrenal Gland Hormones → Adrenal Cortex

• Three Layers produce hydrophobic hormones

  • Steroids

  • Mineralocorticoids → primarily aldosterone

    • good for retaining water in our body

  • Glucocorticoids → primarily cortisol

    • important for glucose levels

  • Androgends → primarily dehydroepiandrosterone (DHA)

    • armpit hair

    • pubic hair

The Adrenal Medulla and Stress

• Adrenal Medulla is a modified sympathetic ganglion

  • Innervated by preganglionic neurons

• Releases epinephrine (primarily) in stress

Roles of EPI

• Involved in “flight or flight” response

• Increases the elves of blood fuel (glc and f.a.)

T/F: stress makes us adaptive

True, stress makes us adaptive to situations, but too much is bad

What is Stress?

• Alarm: Flight or Flight

• Resistance: Allostatic Response

• Exhaustion: Chronic stress overwhelms them permanently kills or injures

T/F: CRH goes up in response to stress

True this is because we get a neural inout of stress that goes to the hypothalamus and then to the CRH

Stress Response

1. Neural input (stress)

   ↓

2. Hypothalamus

   ↓

3. Plasma CRH

   ↓

4. Anterior Pituitary

   ↓

5. Plasma ACTH

   ↓

6. Outer layer of Adrenal Cortex

   • Cortisol Secretion

   ↓

7. Plasma cortisol → influence blood glc lvls

Cortisol (CORT) release effects

• Promotes Protein Breakdown → raise blood amino acid lvls → liver GNG (produce glc in liver and liver lets go of it → fuel)

• Glucose Sparing → tissues that absolutely need it and the tissues that don’t will get glucose uptake inhibited

More Effects of Cortisol

“Permissive” Actions:

• Required for other hormone action

• H1 requires H2 to work

Immunosuppressive and Anti-Inflammatory Effects:

• Decreases inflammatory factors following an infection

  • Turns down immunoresponse →get sick when under stress

Carrier Protein (CBG)

holds onto glucocorticoid and keep it in a soluble state

What negative feedback occurs in CORT signaling?

A) CORT directly exerts (-) feedback on CRH and ACTH release

B) CRH directly exerts (-) feedback on CRH and ACTH release

C) CORT directly exerts (-) feedback on CORT, CRH and ACTH release

D) ACTH directly exerts (-) feedback on CORT and CRH release

E) ACTH and CORT directly exert (-) feedback on CRH release

A) CORT directly exerts (-) feedback on CRH (Hypothalamus) and ACTH (Anterior Pituitary) release

T/F: CRH induces ACTH release

True

Adrenal Androgens: Dehydroepiandrosterone (DHEA)

• Major Sex hormone from the adrenal gralnd

Functions:

• puberty growth

• maintains female sex drive

• induces pubic and axillary hair growth

(in males their testosterone from testes is much more potent)

Excess Cortisol Secretion leads to what Disease?

Cushing’s Syndrome/Disease

Excess Cushing’s Syndrome/Disease

Primary Hypercortisolism:

• Adrenal gland cranks out too much cortisol and does it independent of ATCH (little to a lot to nothing)

Secondary Hypercortisolism:

• Overproducing ACTH in the Anterior Pituitary (neg feedback)

“Exogenous” Hypercortisolism:

• Excessive use of synthetic glucocorticoids

  • This can be cream used on inflammatory things like itchiness

What happens w/excessive corticoid signaling?

• elevated protein breakdown and muscle wasting

• elevated blood glc goes up (CORT will display fat dispositions)

  • chubby face small arms and legs

Adrenocortical Deficiency

• not producing enough of the hormones (CORT) coming out of the adrenal gland

  • These patients lack ALL cortical hormones

• Aldosterone deficiency

  • Blood Iron concentrations were messed up

    • Elevation in blood potassium (hyperkalemia)

    • Low sodium levels (hyponatremia)

• Cortisol Deficiency → poor stress response

  • Low blood glucose

  • Lack of permissiveness on SNS action

• Patients are fatigue easily, suffer wieght loss, hypotension, and hypoglycemic

T/F: If you have Adrenocortical Deficiency you have low blood glucose levels

True, this is because

• Adrenal Cortex is not producing enough of the cortisol hormone

  • Cortisol raises blood glucose during stress or fasting → to use up your energy supply when you need to flight or fight → sympathetic

    • it also stimulates GNG to make new glucose in the liver

T/F: If you have Adrenocortical Deficiency you dont lack permissiveness on SNS action

False you actually do lack it because

• Adrenal Cortex is not producing enough of the cortisol hormone

  • Cortisol helps cells respond to epinephrine and glucagon