Week 1 - overview Flashcards
How can you identify the ureters on an x-ray?
-Runs down tips of transverse processes
Describe the macroscopic structure of the kidney
- Parenchyma is the muscle and supporting tissue
- Cortex lays just inside the capsule
- Medulla is organised into pyramids
Are the kidneys intraperitoneal or retroperitoneal?
-Retroperitoneal
What % of TBW is water?
-60% (approx 40L)
Describe the distribution of fluid within the body
- ICF = 25L
- ECF = 15L (divided into interstitial>plasma>lymph>transcellular)
What is osmolality?
-Solute per Kg of solvent
What is osmolarity?
- number of osmoles per litre
What happens to the water in cells with high ECF osmolarity?
-Moves out of cells into ECF
How much urine produced on average per day?
-1.5L
What is the functional unit of the kidney?
-nephron
Which part(s) of nephron in cortex and medulla?
- PCT and DCT in cortex
- Loop and CD in medulla
How much water is recovered in normal balance?
-over 99%
How much Na and Cl recovered in normal electrolyte balance?
-99%
How much bicarb, a’a and glucose recovered in normal water and electrolyte balance?
-100%
What determines GFR?
-The pressure in the afferent and efferent arterioles
What is bulk transport?
-The mass movement of water which is reabsorbed in the PCT following Na reabsorption
How much Na and H2O reabsorbed in PCT?
= approx. 67%
Where is the major site of glucose reabsorption?
-PCT (100%)
How come the filtrate remains isotonic in PCT even though Na removed?
-Water follows down concentration gradient
Why are the epithelial cells of tubules polarised?
-Allows transport across epithelium
Why are there tight gap junctions between tubule epithelia?
-The reduce fluidity and prevent channels and transporters moving to opposite sides
What pump is present on the basolateral side of all tubule cells?
-NaKATPase
Describe Na reabsorption in PCT
- NaKATPase pumps 3Na out and 2K in
- Creates Na gradient
- Na enters across apical membrane down its concentration gradient.
How does Na movement in PCT drive movement of other ions and molecules?
-Energy from Na movement drives reabsorption of other substanced such as glucose and a’a via symporters