homeostasis Flashcards
(13 cards)
Explain why glucose of found in the urine of a person with untreated diabetes
1.A person with untreated diabetes has a high blood glucose concentration
2.Less glucose is reabsorbed into the blood in the proximal convoluted tubule
3.Carrier/ co-transport proteins woking at maximum rate
Describe and explain how he secretion of ADH affects urine produced by the kidneys
- DCT and collecting duct are more permeable
- More water is absorbed into the blood by osmosis
- Smaller volume of highly concentrated urine being produced and less water is lost
Explain how the cells of the PCT are adapted for this function
- Microvilli of epithelial cells provide a large surface area
- Many mitochondria to provide energy for active transport
- Membrane contains many co-trasnporter proteins for facilitated diffusion
Suggest how the binding of a substance to receptor proteins on the outside of a cell leads to a protein being activated by enzyme
- Binding results in a change if tertiary structure of receptor
- Activates enzyme
How can damage to nervous system affect how much heart rate increases and decreases in response to blood pressure rising and falling
- Damages autonomic nervous system
- Damage to baroreceptors
- When blood pressure drops damage means that sympathetic neurones don’t speed up heart rate enough
- When pressure rises parasympathetic neurones don’t slow down heart rate enough
Explain how increasing a cells sensitivity to insulin will lower blood glucose concentration
- More insulin binds to the receptors
- Stimulates uptake of glucose by transport proteins
Suggest how a disorder that damages the kidney glomerus leads to high quantities of protein in urine
- Damages basement membrane
- Proteins enter the glomerular filtrate
Describe how ultrafiltration occurs in the glomerus
- High blood pressure
- Named substances move out eg water and glucose
- Through gaps called fenestrations
- Through the basement membrane
Why does concentration of urine increase as thickness of the kidney medulla increases
- Longer loop of henle
- More sodium ions actively transported out
- Water potential gradient is maintained for longer so more water is reabsorbed
why does the volume of an osmoreceptor decrease when a person is dehydrated
- Water potential of blood will decrease
- Water moves out of the cell by osmosis down water potential gradient into the blood
Give two factors that could affect the concentration of creatinine in the blood
- Exercise and muscle/body mass
Why are all the people in an investigation of volume of water produced after taking drugs given the same food?
- Affects water potential of the blood and affects volume of urine
Give two reasons why a weight loss programme couldn’t be used to treat type 1 diabetes
- Type 1 do not produce insulin
- Weight not linked to type 1 diabtetes
