Homestasis- Topic 6C

Question 1

What is Negative feedback

Answer 1

The change produced by a system to restore systems to their original level.

Question 2

What is Glycogenisis

Answer 2

blood glucose conc too high so liver produces enzymes that mean glucose converted into glycogen (stored in liver cells)
genesis means to make

Question 3

What is Glycogenolysis?

Answer 3

When blood glucose concentration is too low ezymes in liver break down glycogen into glucose
lysis means to breakdown

Question 4

What is the importance of maintaining a stable core temperature and stable blood pH?

Answer 4

So cells can function normally and stop them being damaged. -e.g. enzymes being denatured

Question 5

Glucose is needed for ………, so a lack of glucose in the blood could result in …. …….

Answer 5

respiration, cell death

Question 6

When will blood glucose increase and decrease?

Answer 6

following ingestion of food or drink containing carbohydrates and will fall following exercise or if you have not eaten

Question 7

What two things change the concentration of glucose in your blood?

Answer 7

Eating and Exercise

Question 8

Name the 2 hormones responsible for controlling glucose concentration

Answer 8

Insulin

Glucagon

Question 9

What is the role of beta cells?

Answer 9

to secrete insulin into the blood

Question 10

What is the role of alpha cells?

Answer 10

to secrete glucagon into the blood

Question 11

Describe how blood glucose concentrations are lowered when it’s too high

Answer 11

insulin binds to specific receptors on surfaces of target cells
increases the permeability of muscle-cell membranes to glucose ( MORE TRANSPORT PROTEINS) so cells can take in more glucose (inc the number of channel proteins)
insulin activates enzymes in liver and muscle cells to convert glucose to glycogen (glycogenesis)

Question 12

Describe how blood glucose concentrations are increased when it’s too low

Answer 12

Binds to specific receptors on cell membranes of liver cells
activates enzymes in liver cells that breaks down glycogen into glucose (glycogenolysis)
also activates enzymes involved in formation of glucose from glycerol and amino acids (gluconeogenesis)

Question 13

What is gluconeogenesis?

Answer 13

The formation of glucose from glycerol and amino acids

Question 14

The role of adrenaline

Answer 14

secreted when low conc of blood glucose in your blood.

makes more glucose available for muscles to respire

Question 15

How adrenaline works…

Answer 15

binds to receptors on membrane of liver cells
activates glycogenolysis
inhibits glycogenesis
activates glucagon secretion and inhibits insulin secretion

Question 16

Main function of the Kidneys?

Answer 16

Excrete waste products like urea and regulate water potential of the blood.

Question 17

Name an adaptation of the PCT

Answer 17

Lots of microvilli on epithelial cells increasing SA for faster reabsorption.

Question 18

Name 2 substances present in the glomerular filtrate

Answer 18

Water

Glucose

Question 19

Name the 3 layers that the liquid/small molecules pass through to form glomerular filtrate.

Answer 19

capillary wall
basement membrane
epithelial layer

Question 20

Name 2 substances that are too big to pass through the 3 layers, so can’t be in glomerular filtrate

Answer 20

Proteins

Blood cells

Question 21

What is urine usually made up of

Answer 21

water
urea
other e.g. hormones