Unit 11 - Renal Structure and Function Flashcards
Why is the right kidney slightly lower than the left?
B/c the liver is mostly on the right side
- give the liver more room
True or False:
Kidneys are not protected by the peritoneal membrane
True
What are the kidneys protected by?
Two fatty tissue layers
= “renal fat pad”
What are the two functions of the “renal fat pads”?
- Holds up the kidneys in the abdominal cavity (so they don’t drop and cut off blood vessels)
- Protection
What happens during anorexia nervosa?
Overall fat is reduced in the body - including the “renal fat pads”!
- Kidneys drop and blood supply can be cut off
Where will pain be felt if there is inflammation of the kidneys?
Flank pain
What percentage of body mass makes up the kidneys? What percentage of cardiac output do they receive?
0.4% of body mass
22% of cardiac output!
- this is 55x more blood then they are entitled to receive based on size and weight
Why do the kidneys receive so much blood (cardiac output)?
B/c their role is to filter blood ….
What happens if the cortex layer of the kidney become thin?
There will be less filtering
What is the main function of the kidneys?
Filters blood plasma, eliminates waste, and returns useful substances to the blood
What do the kidneys secrete to regulate the number of RBCs in circulation?
Erythropoietin
What do the kidneys secrete to regulate blood pressure and electrolyte balance?
Renin
- activates angiotensin II
What do the kidneys excrete (8)?
- Urea
- Metabolic wastes
- Toxins
- Drugs
- Hormones
- Salts
- H+
- Water
What does it mean if there is a high level of creatinine in blood circulation?
The kidneys aren’t functioning properly
What are the three main functions of the nephron?
- Filter
- Reabsorb
- Secretion
Why does the afferent arteriole have a wider diatmeter than the efferent arteriole?
Helps to maintain higher pressure in the renal corpuscle
- big input and small output (big artery, small vein)
What is important to note about the filtration at the renal corpuscle?
It is non-selective
- only BIG things won’t be filtered (proteins/lipids)
What are the three forces involved in creating filtration pressure in the renal corpuscle?
- Blood hydrostatic pressure
- Colloid osmotic pressure
- Capsular pressure
What is the average blood hydrostatic pressure normally?
60 mmHg (out)
What is the average colloid osmotic pressure normally?
32 mmHg (pushing back)
What is the average capsular pressure normally? Describe what this pressure is.
18 mmHg (pushing back) - fluid that has collected in the capsule
What is the overall net filtration pressure of the renal corpuscle (glomerus)
10 mmHg (out)
What are 5 things that can decrease blood hydrostatic pressure?
- Shock
- Reduced systemic blood pressure
- Reduced perfusion of the kidneys
- Hemorrhage (decreased blood volume)
- Atherosclerosis (obstruction of renal arteries by plaque)
What happens to urine production if colloid osmotic pressure decreases?
Increase in urine production
- there would be less force opposing blood hydrostatic pressure
What would cause the colloid osmotic pressure to decrease?
If the liver wasn’t functioning well
- fewer blood proteins = lower colloid osmotic pressure
What happens to urine production and capsular pressure if there is an obstruction in the collecting ducts?
Obstruction = MORE fluid is going to collect
- increase the (-) number of capsular pressure
- more pressure will oppose blood hydrostatic pressure
= LESS urine output
What is the GFR?
Glomerular filtration rate
What is the average GFR for a male?
125 mL/min
= 180 L/day
What is the average GFR for a female?
105 mL/min
= 150 L/day
What happens to urine output if there is an increase in GFR? What could it result in?
Urine output rises
- could result in dehydration and electrolyte depletion
What happens if there is a decrease in GFR?
Wastes accumulate
- Azotemia is possible
What is Azotemia?
Excess ammonia levels in blood