F214 1.3 - Hormones Flashcards
Endocrine gland
An organ that secretes hormones directly into the blood.
Exocrine gland
A gland that secretes substances via a duct
Hormone
Chemical secreted by an endocrine gland into the bloodstream, which brings about a response in an organ elsewhere in the body.
Target tissue
A group of similar cells that possess a specific receptor on their cell surface membrane. The shape of the receptor is complementary to the shape of a particular hormone molecule & the tissue is therefore affected by the hormone
First messenger
A molecule that binds to a receptor in the cell surface membrane & causes changes to happen in the cell e.g. adrenaline is a first messenger
Second messenger
A chemical inside the cell released in response to a hormone binding to the cell surface membrane e.g. cAMP
Adenyl cyclase
An enzyme that produces cAMP in the cytoplasm in response to the binding of a signal molecule (e.g. adrenaline) with a receptor in the cell surface membrane
Cyclic AMP (cAMP)
A second messenger produced as a result of adrenaline binding with a receptor in the cell surface membrane; it is also produced as a result of many other interactions between signal molecules and their receptors.
α cells
Cells in the islets of Langerhans that secrete glucagon
β cells
Cells in the islets of Langerhans that secrete insulin
Insulin
A hormone secreted by β cells in the islets of Langerhans in the pancreas in response to high blood glucose levels, which brings about an increase in the uptake of glucose from the blood & so causes a fall in blood glucose levels.
Glucagon
A hormone secreted by α cells in the islets of Langerhans in the pancreas in response to low blood glucose levels, which brings about an increase in blood glucose levels by converting glycogen in liver cells to glucose.
Gluconeogenesis
The production of glucose from non carbohydrate substances, such as amino acids or lipids.
Glycogenolysis
The conversion of glycogen to glucose
Glycogenesis
The conversion of glucose into glycogen
