Renal System Flashcards
Name the roles of the kidney
OSmolarity Ion blance pH waste Extra cellular volume
Does a healthy kidney
Produce hormones
YES
What is the main function of the kidney?
Homeostatic regulation of water and ion content of blood
Where are the ureter?
Tube linking kidneys to bladder
On the Kidney where is the Cortex Medulla Renal pelvis capsule
Cortex- outer layer
Medulla- inner layer
Renal pelvis- large tube
capsule- surrounding kidney
Name the parts of the nephron
Afferent arteriole Glomerulus Proximal tubule Loop of henle Distal tubule
Describe the key processes of the Nephron
Blood enters through the Afferent arteriole through the glomerulus
bowman’s capsule the filtrate is removed
In the proximal tubule reabsorption back into blood and secretion occur
In the loop of henle reabsorption occurs
DIstal tubule and collecting such have reabsorption and secretion
How many liters filter though the Bowmans capsule per day
108L
What % of fluid is reabsorbed in the proximal tubual
How many litres per day
70%
54L/day
What % of fluid is reabsorbed in the loop of henle
How many litres per day
90%
18L/day
What % of fluid is reabsorbed in the distal loop/collecting duct
How many litres per day
99%
1.5L/day
What is the acidity and osmolarity of nephron
Acidity increased down the nephron
Osmolarity decreases
What are the 3 barriers filtrate has to pass through?
1st- Glomerular Capillary Endothelium
2nd- Basal Lamina
3rd- Epithelium of Bowman’s Capsule
Is the glomerulus high pressure?
YES
Name the layers of the glomerulus
Endothelium
Filtration slits
Podocytes pedicels
Filtration membrane
List the forces which infiltrate glomerular filtration and the units
Capillary blood pressure- 30mm Hg
Osmotic pressure- 55mm Hg
Fluid pressure- 15mm Hg
What equation finds Net filtration pressure
Capillary blood pressure -Osmotic pressure -Fluid pressure
GFR filtration efficiency=
125ml/min 180L/day
What is the filtration coefficient made up of ?
Surface area of glomerulus capillaries
Permeability to endothelial cells
What is the definition of Chronic kidney disease?
a GFR of less than 60ml/min
When does GRF increase and decrease?
Decreases with age
Increase during pregnancy
What is the most common physiological regulator of the GFR?
Changes in afferent arteriole resistance.
What are the effects on increased the blood pressure on the renal system?
Constricts afferent arteriole, dilates efferent
What are the effects on decreased the blood pressure on the renal system?
Dilate afferent arteriole, constrict efferent
What does vasoconstriction of the efferent arteriole cause?
Increases hydrostatic pressure in the glomerulus capillaries
GFR increases
What does dilation of the efferent arteriole cause?
Decreases glomerular capillary hydrostatic pressure
GFR decreases
What is the myogenic response to GFR regulation?
Increase in blood pressure activates stretch sensitive ion channels that open
Smooth muscle cells depolarise and contract
Vasoconstriction increases - resistance to flow so blood flow through
arteriole diminishes. Decrease in blood flow Decreases filtration pressure
within the glomerulus.
What is tubuloglomerular feedback?
Regulates GFR
Using BP and net filtration pressure
How does tubuloglomerular feedback work if GFR increases?
Flow through tubule increases
Flow past macula dense increases
Paracrine diffuses from macra densa to afferent arteriole
Resistance in afferent arteriole increases
HP in glomerular decreases
GFR decreases
How do hormones and neurons respond when systemic blood pressure drops
If systemic blood pressure drops sharply e.g. hemorrhage or severe dehydration, sympathetically induced vasoconstriction of arterioles decreases GFR and renal blood flow.
Podocytes change size
name the hormone vasoconstrictor and vaso dilator
Angiotensin II- vasoconstrictor
Prostaglandin- vasodilator
How do we measure renal function GFR?
Creatinine levels in the urine
Normal levels are 88–128 mL/min for healthy women and 97–137 mL/min for healthy men.
Define reabsorption
Movement of filtered solutes and water from the lumen of the tubule back into the plasma
How much of urea is reabsorbed?
50%
Describe the process of reabsorption
Substance must first be transported across the tub ular epithelial membrane into the renal interstitial fluid and then through the peritubular capillary membrane back into the blood
The concentration gradient of a molecule determines__
The mechanism required to transport it across the membrane
What are the 2 types of active transport?
Primary-directly uses metabolic energy
Secondary- uses energy from an electrochemical gradient to drive transport
How is water reabsorbed in the renal system?
Passively by osmosis and coupled to solute reabsorption. The ascending loop of Henle is virtually impermeable to water
How can we increase osmolarity of interstitium?
Moving solutes/ions into interstitium creates favourable conditions for water re-absorption
Describe Na transport across the epithelium
Na+ transporters
Na/K ATPase
Na AT into the epithelial cell from the lumen
Na linked glucose reabsorption
How is the transport rate determined?
Na+ load
several hormones and neurotransmitter
Urea is reabsorbed in the ____ with ____
Urea is reabsorbed in the proximal tubule and collecting duct with H2O
Describe the process of secretion and excretion, describe where
in the nephron this occurs and how.
Secretion is the transfer of molecules from the extra cellular fluid into the lumen
Of the nephron.
Depends mainly on membrane transport systems
These substances are present in great excess, or are natural poisons.
Many drugs are eliminated by tubular secretion
What is the equation to find the amount of solute excreted?
Amount filtered- amount reabsorbed + amount secreted
