Chapter 19-20 (kidney physiology) Flashcards
Describe the glomerular filtration. What are the results?
It basically cleans the blood by getting rid of all the waste and stuff and turns the waste and stuff into urine (filtrate) (only 1%).
180L of blood is filtered in 24 hours and only 1% of filtrate turns into urine
What makes the filtration process in the glomerulus so efficient?
The diameter of the arteriole in the glomerular is bigger so that is what makes it more efficient
What determines the hydrostatic pressure in the glomerulus? How is this different from normal capillaries in the body?
The large input of the afferent arterioles and the small output of the efferent arterioles.
Name all the pressures in the renal corpuscle (5)
- Glomerular Hydrostatic pressure
- Capsular hydrostatic pressure
- net hydrostatic pressure
- Blood colloid osmotic pressure
- net filtration pressure
What do each of the pressures in the renal corpuscle do?
- Glomerular Hydrostatic pressure
- Capsular hydrostatic pressure
- net hydrostatic pressure
- Blood colloid osmotic pressure
- net filtration pressure
- Glomerular Hydrostatic pressure- the primary force that drives the filtration of fluid from the blood within the glomerulus into the Bowman’s capsule (pushes out)
- Capsular hydrostatic pressure- it is back pressure on the glomerular hydrostatic pressure and provides resistance on it and opposes it (pushes in)
- net hydrostatic pressure- pushes fluid from the glomerular capillaries into Bowman’s capsule
- Blood colloid osmotic pressure- Draws fluid into the capillary beds
- net filtration pressure- Determines the rate of at which fluid is filtered from the blood into the Bowman’s capsule
Which pressures oppose on each other in the renal corpuscle?
The Capsular hydrostatic pressure, and Blood colloid osmotic pressure GO AGAINST THE Glomerular hydrostatic pressure
Which pressures work together in the renal corpuscle?
The Capsular hydrostatic pressure, and Blood colloid osmotic pressure
What is NHP (net hydrostatic pressure)/NFP(Net filtration pressure)?
NHP (Net Hydrostatic Pressure)- is the glomerular hydrostatic pressure (GHP) MINUS the Capsular hydrostatic pressure (CsHP), GHP - CsHP (35mmHg)
NFP (Net Filtration Pressure)- It is the Blood Colloid Osmotic pressure (BCOP) MINUS Net Hydrostatic pressure (NHP). BCOP - NHP (10-15mmHg)
What is the GFR?
It is the amount of filtrate produced in one minute
How do you measure the GFR?
You use the creatinine clearance test and Inulin test
Describe the creatinine clearance test
It measures the amount of creatine that is removed from the blood per minute since glomerular filtration gets rid of the creatine in the kidneys
name the steps of the RAAS
- a decrease in NA+ makes your blood volume drop and blood pressure
- They juxtaglomerular apparatus sense this drop of blood volume and blood pressure
- Granular cells secrete renin
- The liver converts renin into angiotensin I
- ACE enzyme converts angiotensin I into angiotensin II
- Angiotensin II stimulates (turns on) the adrenal cortex to make aldosterone and does vasoconstriction
- Aldosterone promotes reabsorption of NA+ and secretion of K+ from ducts
- Increase blood volume and raises blood pressure
What stimulates the RAAS system? And what are the results?
Decrease in blood volume/ pressure
Results: Water and Na+ is reabsorbed causing the blood pressure and blood volume to increase
Describe how water reabsorption works in the nephron loop (the countercurrent multiplication)
The thin descending limb in the nephron loop is where you start to lose the most fluid/water as you are going down the loop since it is permeable to water (lets it leave) and impermeable to solutes (keeps it in) since the ascending loop is releasing a lot of solutes so water follows BUT you gain water/fluid as you go up the thick ascending limb in the nephron loop since it is impermeable to water/fluid (doesn’t let water out) and soluble to solutes (lets them out) which lets the solutes leave but keeps the water in and doesn’t follow the solutes leaving. POSITIVE FEEDBACK SYSTEM
How do the kidneys manage blood pH?
By reabsorbing bicarbonate into the body and secreting H+ ions by peeing
What is the difference between tubular secretion and tubular reabsorption?
Tubular secretion: It removes additional waste (bad stuff) from the blood and puts it into the tubular fluid
Tubular reabsorption: It removes useful solutes (like glucose) from the tubular fluid and puts it back into the blood
Where does tubular secretion and tubular reabsorption occur?
Tubular secretion: primarily in the distal and collecting tubules of the nephron
Tubular reabsorption: proximal convoluted tubule
What is the difference in structure between the proximal convoluted tubule and distal tubule?
proximal convoluted tubule: It has simple cuboidal epithelium with microvilli, it reabsorbs a lot of nutrients and secretes some BUT can do it on its own and not rely on hormones, carries fluid to the nephron loop
distal tubule: It has cuboidal epithelium but no microvilli, it reabsorbs and secretes depending on the hormones aldosterone and parathyroid hormone, empties the filtrate into the ducts
What is the difference in function between the proximal convoluted tubule and distal tubule?
proximal convoluted tubule: It reabsorbs and secretes a bulk of stuff to stay at homeostasis
distal tubule: It reabsorbs and secrets stuff in a detailed manner and regulate the levels of things
What is the main function of the collecting ducts?
It determines the concentration and volume of urine and moves it to a place where it can be released. IT IS CONTROLLED BY HORMONE ADH, ALDOSTERONE, AND NATRIURETIC PEPTIDES
What are the characteristics of urine? (7)
- output (1-2 L per day)
- color (yellow due to urobilin or heme, darker yellow the more dehydrated)
- specific gravity: the density of your urine to see how hydrated you are
- pH (4.5- 8 the average is 6)
- odor (due to ammonia, acetones or ketones
- bacteria (NONE IT IS STERILE)
- excretes nitrogenous wastes (urea- waste of amino acid metabolism) (creatinine - waste of muscle metabolism) (uric acid (waste of nucleic acid metabolism)
What is the main purpose of the nephron loop?
TO REABSORB WATER
Where does urea, creatinine, and uric acid come from? (what is it?)
- Urea- waste of amino acid metabolism
- Creatinine - waste of muscle metabolism
- Uric acid waste of nucleic acid metabolism
