Homeostasis Exam Questions
No description yet. This curated deck is ready for daily study.
Card preview (16)
Stimulation of Osmo receptors can lead to secretion of the hormone. ADH describe and explain how the secretion of ADH affects urine produced by the kidneys.
Permeability of membrane / cells (to water) is increased; 2. More water absorbed from / leaves distal tubule / collecting duct; 3. Smaller volume of urine; 4. Urine becomes more concentrated
When a person is dehydrated, the cell volume of an Osmo receptor decreases explain why
Water potential of blood will decrease; 2. Water moves from osmoreceptor into blood by osmosi
Describe how urea is removed from the blood
Hydrostatic pressure / description of pressure / description of how pressure generated; Causes ultrafiltration (Allow description of ultrafiltration) at Bowman’s capsule / glomeruli / renal capsule; Through basement membrane; Enabled by small size urea molecule;
Explain how urea is concentrated in the filtrate
Reabsorption of water / by osmosis; At the PCT / descending LoH;
Describe how ultrafiltration produces glomerular filtrate
• Blood pressure / hydrostatic pressure; Small molecules / named example; Pass through basement membrane / basement membrane acts as filter; Protein too large to go through / large so stays behind; Presence of fenestrations in capillaries / presence of podocytes;
Some people who have diabetes do not secrete insulin. Explain how a lack of insulin affects reabsorption of glucose in the kidneys of a person who does not secrete insulin.
• High concentration of glucose in blood; • High concentration in tubule / in filtrate; • Reabsorbed by facilitated diffusion / active transport; • Requires proteins / carriers; • These are working at maximum rate / are saturated; • Not all glucose is reabsorbed / some is lost in urine;
A diabetic person and a non-diabetic person each ate the same amount of glucose. One hour later, the glucose concentration in the blood of the diabetic person was higher than that of the non-diabetic person. Explain why.
Lack of insulin / reduced sensitivity of cells to insulin; Reduced uptake of glucose by cells / liver / muscles; Reduced conversion of glucose to glycogen;
The urine of a non-diabetic person does not contain glucose. Explain why.
Leaves the blood at kidney; Taken back into blood / reabsorbed (from kidney tubule);
A high blood glucose concentration could cause glucose to be present in the urine of a diabetic person. Suggest how.
Large amount / high concentration of glucose in filtrate; Cannot all be reabsorbed / 1st convoluted tube too short to reabsorb all of glucose / saturation of carriers;
If the glomerular filtrate of a diabetic person contains a high concentration of glucose, he produces a larger volume of urine. Explain why.
G lucose in filtrate lowers water potential; Ignore ‘urine’. Accept increase solute potential Lower Ψ gradient / less difference in Ψ filtrate − Ψ plasma; Ignore ‘concentration’ Less water reabsorbed by osmosis;
Explain the shape of the loop of Helme in the graph
Concentration rises in descending limb because sodium ions enter and water lost; Concentration falls in ascending limb because sodium ions (and chloride) ions actively removed; But water remains (in ascending limb) because its walls are impermeable (to water).
Explain why glucose would be found in urine of untreated diabetic person
High concentration of glucose in blood/filtrate; Not all the glucose is (re)absorbed at the proximal convoluted tubule; Carrier/co-transport proteins are working at maximum rate Carrier/co-transport proteins/ are saturated;
Describe role of glucagon in gluconeogenesis
(Attaches to receptors on target cells and) activates/stimulates enzymes; Glycerol/amino acids/fatty acids into glucose;
Explain how increasing a cell’s sensitivity to insulin will lower the blood glucose concentration.
More) insulin binds to receptors; 2. (Stimulates) uptake of glucose by channel/transport proteins OR Activates enzymes which convert glucose to glycogen;
Explain how inhibiting adenylate cyclase may help to lower the blood glucose concentration.
Less/no ATP is converted to cyclic AMP/cAMP; 2. Less/no kinase is activated; 3. Less/no glycogen is converted to glucose
Explain how the formation of glycogen in liver cells leads to a lowering of blood glucose concentration.
Glucose concentration in cell / liver falls below that in blood (plasma) which creates / maintains glucose concentration / diffusion gradient; Glucose enters cell / leaves blood by facilitated diffusion / via carrier(protein) / channel (protein);