Urinary system Flashcards
What makes up the urinary system?
2 kidneys, 2 ureters, bladder, urethra
How many nephrons does each kidney have?
about 1 million
How much blood plasma gets filtered by the kidneys each day?
180L
How much is an average amount of pee/day?
1L
What happens to substances in the renal tubule?
It gets excreted
What happens to substances in the peritubular capillaries?
It gets reabsorbed back into bloodstream
How does urine descend the ureters?
Mostly by peristalsis but also assisted by gravity
How do kidneys keep BP in range?
by controlling sodium channels. If they secrete sodium, water will follow and reduce blood volume and thus blood pressure. If they reabsorb sodium, water follows and blood volume increases as well as BP
What happens with diuretics?
Cause more water to go into renal tubule and stay there
If blood pressure gets too low from diuretics… how can that effect your heart?
HR will increase to abnormal pace (tachycardia)
What is the normal osmolarity of blood?
290 mOsm/L
When do kidneys secrete EPO?
When oxygen is decreased out of range. It stimulates RBC maturation
How does renin increase blood pressure?
Renin helps kidneys reabsorb Na ions when blood pressure is low. It closes sodium channels, causing sidum to go in to peritubular capillaries and water follows, so you increase blood volume and thus BP
In normals, what happens when glucose blood conc. increases out of range?
Pancreas beta cells secrete insulin, which trigger GluTs to migrate to plasma membrane to allow glucose to enter tissue cells and create ATP.
In normals, what happens when glucose blood conc. decreases out of range?
Pancreas alpha cells secrete glucagon, which binds in liver cells to cleave glycogen and releases glucose into the bloodstream
In type 2 diabetes, insulin is secreted BUT…
the cell is resistant: so glucose in the bloodstream is too high chronically, so blood vessels get damaged. Glucose clings to RBCs and cause them to stick and not pass through capillaries, which stops the flow of blood, hence amputations and blindness.
What is diabetes?
A disorder of blood sugar regulation caused by inability to secrete (1) or use insulin (2)
What happened to beta cells in Type 1 diabetes patients?
They were destroyed by their immune system so they cannot secrete insulin
How do diabetics develop gangrene, heart disease, etc?
Prolonged usage of fats for energy and too much glucose in the plasma leads to circulation problems
If we are mostly sedentary we don’t need much ATP, and thus less glucose in our cells. What happens in type 2 diabetes?
Our cells close GluTs and put them back in vesicles and leave glucose in the interstitial fluid/bloodstream which increases blood sugar levels to abnormal levels
