Hormonal Communication Flashcards
What is an endocrine gland?
Group of cells specialised to secrete hormones directly into the bloodstream.
Why are hormones considered as chemical messengers?
They carry information from one part of the body to another.
How do hormones work when they are secreted into the bloodstream?
They diffuse out of blood and bind to specific receptors for that hormone (target cells). Once bound, they stimulate the target cell to produce a response.
What are steroid hormones?
- Lipid soluble
- Pass through cell membrane
- Bind to steroid hormone receptors to form a hormone-receptor complex.
- The complex formed acts as a transcription factor which facilitates or inhibits the transcription of a specific gene.
What are non-steroid hormones?
- Hydrophilic
- Bind to specific receptors of the cell surface membrane of target cells.
- Triggers reactions mediated by chemicals called second messengers.
What is an example of a steroid hormone?
Oestrogen
What is an example of a non-steroid hormone?
Adrenaline
How is hormonal communication different from neuronal communication?
Hormonal is... - Slower - Less specific - Longer lasting - Widespread - Irreversible Communication by hormones
What two parts make up the adrenal glands?
1) Adrenal cortex
2) Adrenal medulla
What are the 3 main types of hormones produced by the adrenal cortex?
- Glucocorticoids
- Mineralocorticoids
- Androgens
What the 2 hormone secreted by the adrenal medulla?
- Adrenaline
- Noradrenaline
Adrenaline
Increases heart rate and raises blood glucose concentration
Noradrenaline
Works with adrenaline
Causes increased heart rate, widening of pupils and widening of air passages in the lungs
Androgens
Small amounts of female and male sex hormones are released.
Mineralocorticoids
Main one is aldosterone.
Helps to control blood pressure by maintaining the balance between salt and water concentrations in the blood.
Glucocorticoids
Include cortisol which regulates metalbolism by controlling how the body converts fats, proteins and carbohydrates to energy.
Also corticosterone which regulates the immune system.
What is the exocrine gland?
Produces enzymes and releases them via a duct into the duodenum.
Name 2 Islets of Lanferhans
Alpha and beta cells
What do alpha cells secrete and produce?
Glucagon
What do beta cells secrete and produce?
Insulin
What are the roles of the exocrine gland?
Responsible for producing digestive enzymes and pancreatic juice.
The enzymes and juice are secreted into ducts which leafs to the pancreatic duct.
From here they are released into the duodenum.
What is pancreas made up of mostly?
Exocrine glandular tissue