Hormonal Communication Flashcards
What is meant by an endocrine gland?
A group of cells that produce chemical messengers (hormones) and are secreted directly into the bloodstream
What is a hormone?
A chemical messenger produced by a gland and secreted directly into the bloodstream, which alters the activity of specific target organs
What are some examples of chemicals that could be a hormone? (6)
- Steroids
- Proteins
- Glycoproteins
- Polypeptides
- Amines
- Tyrosine
What is a target cell?
A cell which has receptors on it’s cell surface membrane in which specific hormones can bind to and cause a cascade of reactions
What does a steroid hormone do? (5)
- Steroid hormones are lipid soluble
- So they can pass through the phospholipid bilayer of the cell surface membrane
- And bind to a receptor inside of the cell
- The hormone-receptor complex acts as a transcription factor
- Which inhibits or facilitates the transcription of a specific gene
What does a non-steroid hormone do? (3)
- Hydrophilic so cannot pass through the phospholipid bilayer
- Bind to a specific receptor on the cell surface membrane of target cell
- Triggers a cascade reaction mediated by secondary messengers
What are the two glands that make up the adrenal glands?
Adrenal cortex - outer region
Adrenal medulla - inner region
What hormones does the adrenal cortex release? What are their functions? (6)
- Glucocorticoids - Include cortisol
- regulating metabolism by controlling the conversion of fats, proteins and carbs to energy
- Mineralocorticoids - Aldosterone
- Control blood pressure by maintaining balance of water and salt conc.
- Androgens
- Female and male sex hormones - Smaller impact
What two hormones does the adrenal medulla release? What do they do? (4)
- Adrenaline
- Increases heart rate, converts glycogen to glucose in the liver
- Noradrenaline
- Works with adrenaline, increased heart rate, widening of pupils, widening of air passages in lungs, narrowing of blood vessels in non-essential organs (higher blood pressure)
