Homeostasis Flashcards
What does LH do?
Stimulates growth of ovarian follicle and promotes ovulation.
Promotes development of corpus luteum.
What does FSH do?
Stimulates growth of ovarian follicle.
Stimulates the ovary to produce oestrogen.
What does oestrogen do?
At low concentrations, inhibits release of LH by -ve feedback.
At critical high concentrations, stimulates release of LH and FSH by +ve feedback.
Promotes repair and growth of uterine lining.
What does progesterone do?
At high concentrations inhibits FSH secretion.
A sharp decrease along with a decrease in oestrogens triggers menstration.
What order are menstral hormones secreted in?
FSH
Oestrogen
LH
Progesterone
What is vasodilation?
When it’s hot arterioles near the surface of the skin dilate. More blood flows through the capillaries in the surface layer of the dermis. Meaning more heat lost from the skin by radiation.
What is vasoconstriction?
When it’s cold arterioles near the surface of the skin constrict. Less blood flows through the capillaries reducing heat loss.
What part of the brain is responsible for controlling body temp in mammals?
Hypothalamus
What are the two hormones secreted to control blood glucose levels? What cells secrete them?
Beta cells - insulin
Alpha cells - glucagon
Where does insulin and glucagon bind?
Insulin - receptors on cell membranes of liver and muscle cells
Glucagon - receptors on membrane of liver cells
What does insulin do?
- increases permeability of cell membranes to glucose.
- activates enzymes that convert glucose to glycogen
- increases cellular respiration
What does glucagon do?
- activates enzymes that break glycogen to glucose
- promotes formation of glucose fatty acids and amino acids
What is glyconeolysis?
Glycogen splitting. Hydrolysing glycogen to glucose
What is gluconeogenesis?
New glucose formation. Converting non-carbohydrate substances such as amino acids and glycerol to glucose.
What is glycogenesis?
Glycogen forming. Condensing glucose and storing it as glycogen.
What does adrenaline do?
Binds to receptors in the cell membrane of liver cells. Activates glycogenolysis and inhibits glycogenesis. Activates glucagon secretion and inhibits insulin secretion.
What is homeostasis?
The regulation and maintenance of relatively constant conditions within a organism or other system.
What is an endotherm?
An organism that controls it’s body temperature by internal physiological means as well as by behavioural means.
What are four ways heat can be lost from an organism to the environment.
- Radiation
- Conduction
- Convection
- Evaporation
What is negative feedback?
Returns a system to its normal level. Triggered by a deviation from the norm.
What is positive feedback?
Triggered by a deviation from the norm. Causes a greater deviation in the same direction.
What is a follicle?
A fluid filled ball of cells found in the ovary, contains a developing oocyte.
What is histamine? Where is it released from?
A local chemical mediator that causes inflammation. It is released by white blood cells and by mast cells.
What does cAMP stand for?
Cyclic adenosine monophosphate.
How does adrenaline increase blood glucose levels?
It binds to receptors on liver cells. This activates the enzyme adenylate cyclase. Once adenylate cyclase has been activated ATP binds to the complex. Adenylate Cyclase breaks down ATP into Cyclic AMP, which becomes the second messenger protein in this process. Cyclic AMP activates protein kinase, which activates phosphorylase catalyzing the breakdown of glycogen to glucose.
