Hormones Flashcards
Define exocrine gland
A gland that does not produce hormones but have a small duct or tube to carry their secretion to another place
Define endocrine glands
Glands that secrete hormones directly into the blood stream
Define target cells/tissue
A group of cells that possess specific receptors on their cell membranes that are complimentary to the hormone
What are the 2 types of hormones
Protein/peptide and steroid hormones
Define first messenger
The hormone itself which binds to the receptors on the cell membrane
Define second messenger
Activated be the first messenger the second messenger actually causes the effect inside the cell, allowing for a variety of effects from the same hormone
Describe the function of alpha cells
Detect falls in blood glucose levels and secrete glucagon which is detected by receptors on liver cells which then convert glycogen to glucose and release it into the blood
Describe the function of beta cells
To detect rises in blood glucose levels and secrete insulin into the blood which is detected by receptors on the liver and muscle cells which remove glucose from blood and convert it to glycogen
What is the mechanism of insulin secretion
Cell membrane has potassium and calcium ion channels. The potassium ion channels are normally open so potassium ions flow out. When glucose moves into the cell it is metabolised to produce ATP which closes the potassium ion channels. The build up of potassium ions causes a change in ph causing the calcium ion channels to open. The calcium ions that diffuse into the cell cause the vesicles of insulin to undergo exocytosis releasing it into the blood.
What is type 1 diabetes
The bodies immune system attacks and destroys the beta cells in the pancreas so the body can no longer produce insulin
What is type 2 diabetes
Your cells are unresponsive to the insulin in the blood
