nephron and in the kidney itself

inner section of renal tissue

renal mendulla

outer section of the renal tissue

renal cortex

what are nephrons

functional part of the kidney that does all of the filtering. Is composed of the

1. filter (Bowman’s capsule)

2. Tube (proximal and distal tubule, loop of henle)

3. ducts

blood flow through nephron

1. renal artery

2. afferent arteriole

3. glomerulus

4. efferent arteriole

5. capillary bed

6. renal venule

7. renal vein

8. inferior vena cava

what is the glomerulus

cluster of capillaries that filters the blood, while the bowman’s capsule is a membrane that surrounds it and collects the filtered blood.

glomerula filtration

glomerular filtration is when water and dissolved substances in blood plasma are forced from the glomerulus into the bowman’s capsule

why can filtration happen?

1. permeability of capillaries

2. blood pressure

permeability of capillaries in glomerulus

the pores in the capillaries are large enough for water and particles to pass through, but not big enough for blood and proteins to pass by

blood pressure

the blood pressure in the glomerulus is much higher than any other capillaries (4x higher pressure). This type of pressure is called “non specific pressure” to press everything out that’s small enough

how much blood passes through the kidneys

180-200, and produces about ~180L of glomerular filtrate (stuff that gets filtered in glomerulus). only 1% of the glomerular filtrate gets turned into urine

composition of filtrate

very similar to blood plasma but without the blood cells and proteins

filtrate contains:

Na, K, Cl, ammonium, urea, uric acid, glucode, amino acids

how much percent of filtrate returns to the blood stream after the loop of henle and proximal tube

65%

cells in proximal tubule contain a lot of ____

mitochondria

why is there a lot of mitochondrea near the proximal tubule?

to offer ATP for active transportation

filtrates that are put back into the blood

Na ions, K ions, glucose, amino acids - active transport

Cl and other negatively charged ions - passive transport: attraction to positive ions

water - reabsorbed through osmosis

why is the descending loop of henle very salty

because the descending way is only permeable to water, and the concentration of other filtrates like Na increase

2 parts of ascending