Urinary System Flashcards
Functions of the Urinary system
Balances concencetrations of (Ca, Na, K, Cl, H, etc)
Adjustihg pH
Eliminates waste (drugs, toxins)
Controls blood pressure (volume of blood)
What are the kidneys supported by?
Overlaying peritoneum
Contact with adjacent organs
Supporting connective tissues
Three layers of connective tissue on the kidneys
- firbous capsule
- perinephric fat
- renal fascia
Minor calyx serve how many lobes?
1
Major calyx serve how many lobes?
4-5
What are nephrons innervated by?
renal nerves (sympathetic: adjusts blood flow and renin release)
WHat type of nephrons are there and what time
Cortical nephrons (85%) Juxtamedullary nephrons (15%)
What are corticol nephrons used for?
regulatory functions
What are juxtamedullary nephrons used for?
Water conservation (concentrated urine)
What does the renal corpuscle contain?
2
glomerular capsule (bowmans) capillary network
The main function of the proximal convuluted tubule?
Reabsorption of nutrients from the filtrate (tubular fluid)
What are the main functions of the nephron loop?
2
Establishes osmotic gradient in renal medulla
Promotes water reabsorption
What is the thin limb of the nephron loop made of?
simple squamous
What is the thick limb of the nephron loop made of?
simple cuboidal
What is the main funciton of the distal convoluted tubule?
2
Adjustments to composition of tubular fluid
Secretion and reabsorption
What is the main function of the collecting duct?
final adjustments by passing through osmotic gradient in renal medulla
What are intercalated discs?
cuboidal epithelium with microvilli
What are the function of intercalated discs in the collecting duct?
Secretion/reabsorption of H and bicarbonate (important for pH balance
What are principal cells in the collecting duct?
Reabsorb water and secrete potassium ions
Describe the flow of blood through the kidney
11
Renal artery Segmental Artery Interlobar arterties Arcuate arteries Cortical radiate arteries Afferent arterioles
Glomerulus
Cortical radiate veins
Arcuate veins
Interlobar Veins
Renal vein
What is urea?
Breakdown of amino acids in the liver
Where is the waste product, creatine, produced?
Breakdown of creatine phosphate in skeletal muscles (gives P to ADP, anaerobic)
What is uric acid?
Recycling of nitrogenous bases of RNA
Kidney function requires 3 processes. What are they?
Filtration
Reabsorption
Secretion
Describe filtration
Blood pressure in glomerular capillary pushes water and solutes into capsular space
Describe reabsorption
transport of water and solutes from tubular fluid across membrane to the peritubular fluid
Desribe secretion
Transport of solutes from peritubular fluid to tubular fluid
Where does the majority of reabsorption occur in the kidney?
PCT
Where does the the rest of the reabsorption happen?
Nephron loop
DCT
collecting ducts and they are all in the renal medulla
Where are peritubular capillaries found?
renal cortex
Where is the vasa recta found?
renal medulla
What does the juxtaglomerular complex secrete and what does that stimulate in our nephron?
secretes renin which controls blood pressure
it tells our nephron to let out more water
When is renin secreted?
when glomerular blood pressure decreases
Where does filtration happen in the glomerular capsule?
podocytes in the cell have pedicle and in between the pedicles are filtration slits. That is where filtration happens
What kind of capillaries are in the glomerular capsule?
fenestrated caps
What is the glomerular hydrostatic pressure?
Generally is this pressure high or low and why?
pressure in the glomerular capillaries
This pressure is generally high because its an artery moving from a large capillary to a smaller one
What is the BCOP and what is its goal?
Pressure that draws water out of the filtrate and back into the plasma.
It opposes filtration
What is capsular hydrostatic pressure?
Opposes GHP
Water and solutes out of filtrate and into plasma
What is the usual level of capsular colloid osmtoic pressure?
usually zero
As long as NFP is above zero what will occur?
Water will move out of the plasma and into the capsular space/filtrate
What is regulation of glomerular filtration rate (GFR)?
Amount of filtrate kidneys produce each minute
What will occur if there is a decrease in GFR? (decrease in filtrate and decrease in urine production)
AKA describe autoregulation
5
1a. Dilation of afferent aterioles, 1b. contraction of mesangial cells, 1c. constriction of efferent arterioles
2. Increase in glomerular blood pressure
3. Back to normal GFR
If autoregulation doesnt work what happens? list the steps
Central Regulation occurs
- Juxtaglomerular complex increases production of renin
- Renin triggers release of angiotensin II which triggers 3 things: Contriction of efferent arterioles, aldosterone secretion, neural responses
- These increase blood volume and blood pressure and result in increased glomerular pressure and normal GFR
In central regulation of GFR what does aldosterone secretion cause?
4
Increases Na retention
fluid consumption
Fluid retention
Constriciton of venous reservoirs
In central regulation of GFR what does angiotension in neural respones trigger?
3 actions that lead to 3 actions
- Increased stimulation of thirst centers
- Increased ADH production
- Increased sympathetic motor tone
- which all together increase constriciton of veins
- increased cardiac output
- stimulate peripheral vasoconstriction
In the PCT where does solute increase and decrease?
Where does water flow?
[Solute] decreases in tubular fluid
[Solute] increases in peritubular fluid and adjacent capillaries
Osmosis pulls water out of tubular fluid
What two things happen in the DCT?
Reabsorption AND secretion
15-20% of initial filtrate reaches the DCT
What two pumps are found in the DCT?
Na/K pump and Na/H pump
What is the Na/K pump stimulated by in the DCT?
What does this promote?
Aldosterone
Promotes water absorption into capillaries, increase in blood pressure and increase in blood volume
If the pH of blood gets too acidic what can be done in the DCT?
H ions in the blood can be exhanged for Na ions in the tubular space
How does the DCT play a role in drug/toxin removal?
The DCT has carrier proteins that transport drugs and toxins into the tubular fluid to be excreted in the urine