Corticosteroids Flashcards
(163 cards)
What is the function of the adrenal glands in regards to steroid production?
Secrete mineralcorticoids, glucocorticoids, and sex hormones
Where are the adrenal glands located?
Sit on top of the kidneys
What are the two main areas of the adrenal glands?
Cortex and Medulla
What composes the cortex of the adrenal glands?
Zona Glomerulosa
Zona Fasciculata
Zona Reticularis
(GFR on top of kidneys)
Describe the pathway of hormone synthesis in the zona Glomerulosa?
Cholesterol –> Desoxycorticosterone –> Corticosterone –> 18-Hydroxyxosterone –> Aldosterone
What is the main steroid product of the zona glomerulosa?
Aldosterone
Describe the pathway of hormone synthesis zona fasci?
Cholosterol –> Prenolene –> Progesterone –> 17-Hydroxyprogesterone –> 11-Deoxycortisol –> Cortisol
What is the main steroid product of the Zona Fasci?
Cortisol
Describe the pathway of hormone synthesis in the zona reticularis?
Cholesterol –> 17-Hydroxypregnenolone –> Dehydroepiandrosterone –> Androstenedione –> Testosterone
What cholesterol is used for steroid synthesis?
LDL Cholesterol
Where is testosterone mainly produced? In Who?
Testosterone can be produced in the Zonba reticularis; however, in males, most testosterone is synthesized in the testes
- Little testosterone production in the female ovaries
What does cortisol regulate in the body?
- Mediate the stress response
- Help regulate metabolism
- Help regulate the inflammatory process
- Help regulate the immune system
When is cortisol released? What does it help restore?
Cortisol is released in response to stress and also helps to restore hormone levels when stress resolves
Describe the physiologic pathway of short term stress?
Hypothalmus –> Nerve Impulse –> Spinal Cord –> Preganglionic Symapthetic Fibres –> adrenal Medulla (Secretes amino-acid based hormones) –> Catecholamines (epinephrine and norepinephrine)
What is the physiologic response of short term stress?
- Increased heart rate
- Increased blood pressure
- Liver converts glycogen to glucose and releases glucose to blood
- Changes in blood floe patterns leading to decreased digestive system activity and urine output
- Increased metabolic rate
- bronchodilation
Describe the physiologic pathway of prolonged stress?
Stress –> Hypothalamus –> CRH (corticotropin-releasing hormone) –> Corticotroph cells of anterior pituitary –> ACTH –> Adrenal Cortex ( secretes steroid hormones) –> Releases Mineralcorticoids and Glucocorticoids
In the long term stress response, mineralcorticoids function to:
Retention of sodium and water by kidneys
Increased blood volume and blood pressure
In long term stress, glucocorticoids function to:
- Proteins and fats converted to glucose or broken down for energy (muscle wasting)
- Increased blood glucose
- Suppression of the immune system
What controls the production and secretion of cortisol?
HPA Axis
What is the main function of the HPA axis?
Control the production and secretion of cortisol by the hypothalamus-pituatary-adrenal (HPA) axis
Describe the HPA axis pathway?
Circadian Regulation and/or stressors (hypoglycemia, hypotension, surgery, fever, injury)
V
Hypothalmus
V
Pituatary (acted on by vasopressin and pro-inflammatory cytokines)
V
ACTH
V
Adrenals
V
Cortisol (exhibits negative inhibition on the hypothalamus and pitautary to inhibit cortisol release)
In the HPA axis pathway, cortisol exhibits ________ on the pitauatary and hypothalmus to…..
Negative Inhibition
- Inhibits its own release, when cortisol levels are high, the cortisol inhibits further production
What are the main actions of glucocorticoids?
They suppress inflammatory and immunological responses
Describe the basics of inflammation? What are its purposes?
- Inflammation is a process whereby WBC’s and other mediators protect against foreign substances
- The inflammatory process serves several purposes initially (e.g. removal of damaged cells) but may eventually become counterproductive (e.g. edema impedes blood flow)