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
Define “Ovulation”
an egg being released
Define “Menstruation”
if there’s NO fertilisation, the uterus lining breaks down and leaves the body through the vagina
What does “FSH” do ???
- stimulates the follicle to develop
What is “LH” and what does it do ???
- Luteinising (Martin LUTHER liked ICING) Hormone
- stimulates ovulation
- stimulates the CORPUS LUTEUM to develop
What does “OESTROGEN” do ???
- stimulates the uterus lining to thicken
- INHIBITS FSH being released from Pituitary Gland
What does “PROGESTERONE” do ???
MAINTAINS the thick uterus lining, ready for the implantation of an embryo
How do kidneys normally prevent glucose appearing in the urine of a NON-diabetic person?
- glucose REABSORBED
- by Active Transport
How do we measure Metabolic Rate?
measure the UPTAKE OF OXYGEN
Define “Positive Feedback”
a mechanism which amplifies a change from the normal level
