Unit 5: Homeostasis Flashcards
Define “Negative Feedback”
a CHANGE to the NORMAL LEVEL initiates a response which acts AGAINST the change
Which HORMONES INCREASE blood glucose concentration?
- Glucagon
- Adrenaline
Which hormone DECREASES blood glucose concentration?
Insulin
Where are Glucagon and Insulin secreted? (2 marks)
- in PANCREAS
- by ISLETS OF LANGERHANS
The concentration of glucose in the blood is normally…
90 mg per 100 cm3 of blood
Define “Glycogenolysis”
breakdown of GLYCOGEN —> Glucose
Define “Glycogenesis”
synthesis of GLYCOGEN from Glucose
Ectotherms cannot…
regulate their own body temperatures
What causes slower movements at lower temperatures?
- Molecules have less kinetic energy at lower temperatures
- SLOWER METABOLISM
How does Adrenaline cause blood glucose concentration to increase?
~ Adrenaline binds to receptors in plasma membranes of liver cells
- Adenylate cyclase activated
~ Adenylate cyclase converts ATP into a chemical signal called “Secondary Messenger”
- cAMP produced
- Activates enzymes in cell
- so GlycoGenoLysis occurs
Define “Type 2 diabetes” :
failure to respond to insulin
Is Gene Therapy better than injecting Insulin?
Yes:
- Avoids pain of injections
- LongER lasting
- Less need to measure blood sugar
No:
- Any side effects on humans?
- substitute insulin may be rejected by body
Describe how insulin reduces the concentration of glucose in the blood: (3 marks)
- insulin binds to specific receptors on membranes
- insulin activates the opening of channels
- insulin increases the permeability of muscle cells to glucose
- insulin results in glycogenesis occuring
The Menstrual Cycle is controlled by which 4 hormones?
- FSH (Follicle Stimulating Hormone)
- LH (LUTEINISING HORMONE) - REMEMBER!!!
- OESTROGEN
- PROGESTERONE
Define “Follicle”
an egg and its surrounding protective cells
