Endocrine System - 13.3 Flashcards
How many adrenal glands does the body have and where are they located?
There are two - located on top of the kidney
What is each gland composed of?
Inner area - adrenal medulla
Outer area - adrenal cortex
What hormones does the adrenal medulla produce?
Epinephrine (adrenaline) and norepinephrine (noradrenaline)
What do these hormones regulate?
A short term stress response (fight or flight)
Why is the adrenal medulla considered to be a neuroendocrine structure?
It is formed from nervous system tissue
What stimulates the adrenal medulla to secrete epinephrine and a bit of norepinephrine?
- in response to a stressor, neurons of the SNS - carry a signal from hypothalamus to adrenal medulla
- these neurons stimulate the adrenal medulla to secrete epinephrine and norepinephrine
What effect does epinephrine and norepinephrine have?
- increases breathing rate
- increases heart rate
- increases blood pressure
- blood flow to heart and muscles
- glucose is released in the liver
- pupils dilate
blood flow to extremities decrease
Which lasts longer, hormonal control or nervous system control?
Hormonal control!
What do the stress hormones produced by the adrenal cortex trigger?
The long term response
What does glucocorticoids do?
Increase blood sugar levels
What does mineralcoriticoids do?
Increase blood pressure
What is cortisol synthesized from?
Cholesterol
What is the process for cortisol to be released?
- Brain detects danger
- Directs hypothalamus to secrete releasing hormone
- Releasing hormone stimulates the anterior pituitary to secrete ACTH
- ACTH targets the adrenal cortex
- Adrenal cortex secretes cortisol (stress hormone)
Which is longer lasting, epinephrine or cortisol?
Cortisol
What is the main function of cortisol?
To raise blood glucose levels
How does cortisol raise blood glucose levels?
- Breaks down protein into amino acids
- Amino acids are taken out of the blood by liver
- In liver amino acids are used to make glucose
- Glucose is then released back into the blood
What are the effects of sustained high levels of cortisol?
- impaired thinking
- damage to the heart
- high blood pressure
- diabetes
- susceptibility to infection
- early death
Why does sustained high levels of cortisol make people more susceptible to inections?
Cortisol is an antiinflammatory
Does cortisol inhibit the regeneration of connective tissue?
Yes
What is the process of the effects of adolsterone?
- Stimulates the distal and collective tubules of the kidneys
- increases absorption of sodium into the blood stream
- draws more water from the nephrons (raising blood pressure)
What happens if the adrenal cortex is damaged?
Addison’s disease - the body will secrete inadequate amounts of mineralocorticoids
What are the symptoms of addisons disease?
- hyperglycemia (low blood sugar)
- sodium and potassium imbalances
- rapid weight loss
- general weakness
What happens if there is low aldosterone in the blood?
A loss of sodium and water from the blood due to increased urine output (blood pressure drops)
