5.4 Hormonal Communication Flashcards
What are endocrine glands?
Specialised group of cells to secrete hormones directly into blood without a duct
What are hormones?
Chemical messengers secreted by endocrine glands, and can be steroid or non-steroid.
What are target cells?
Cells that have specific receptors for a hormone that the hormone needs to act on.
What can stimulate a gland to secrete a hormone?
A change in conc of another chemical, or action potentials.
What happens after a non-steroid hormone binds to a receptor on the cell surface membrane?
A G protein activates an enzyme in the cell surface membrane.
What is the first messenger?
The non-steroid hormone because it carries a chemical message from an endocrine gland to the target cell receptor.
What is the second messenger?
The signalling molecule, because it carries the chemical message from the receptor to the other parts of the cell.
What does the 2nd messenger do?
They activate an enzyme cascade in the cell.
What is a target cell for adrenaline?
Hepatocyte
What enzyme catalyses the reaction of ATP > cAMP ?
Adenylyl cyclase
What does a G protein do?
Activate a membrane bound enzyme after a hormone has bound to a receptor.
What type of gland is the adrenal gland?
Endocrine
What is the outer part of the adrenal gland called?
Cortex
What is the inner part of the adrenal gland called?
Medulla
What type of hormones does the adrenal cortex secrete?
Steroid hormones
Why can steroid hormones directly affect DNA and protein synthesis?
They can diffuse through the lipid bilayer into the cell and nucleus.
Where is aldosterone secreted from?
Adrenal cortex
What does aldosterone do?
Maintains blood pressure
How is blood pressure maintained?
Aldosterone increases uptake of Na+ and water, increasing blood volume and pressure.
What type of hormone can suppress the immune system?
Adrenal cortex steroid hormones
Where is cortisol secreted from?
Adrenal cortex
What does cortisol do?
- Controls metabolism of proteins, fats and carbs into glucose.
- Helps development of sexual charecteristics
Why is cortisol released in response to stress?
Controls metabolism to make glucose and energy more available so brain and muscles can coordinate response to stress.
What type of hormone is released from the adrenal medulla?
Non steroid hormones
What hormones are released from the adrenal cortex?
Cortisol and aldosterone
What hormones are released from the adrenal medulla?
Adrenaline and noradrenaline
What are catecholamines?
Amino acid derivative hormones
How does adrenaline increase breathing depth?
Relaxes smooth muscle in bronchioles
What is adrenaline’s primary function?
To make more energy available in the short term to prepare the body for action.
What is hypoglycemia?
Not enough glucose delivered to tissues
What is hyperglycemia?
Blood glucose too high for too long
What cells moniter blood glucose concentration?
Islets of langerhans
What are the target cells of insulin and glucagon?
Hepatocytes in liver
What cells secrete insulin?
Beta cells
What cells secrete glucagon?
Alpha cells
Where are alpha and beta cells found?
Cell clusters in islets of langerhans
What is glucagon?
A non steroid hormone which acts to raise blood glucose concentration
What is insulin?
A non steroid hormone which acts to lower blood glucose concentration
What is glycogenesis?
Glucose converted to glycogen
What is glycogenolysis?
Glycogen converted to glucose
What is gluconeogenesis?
Amino acids/fats converted to glucose
What is the difference between exocrine and endocrine glands?
Exocrine glands have ducts and endocrine are ductless.
