Kidney and Body Fluids 2

1. Blood Supply

   Nota:

   • Supplied by the renal arteries and goes into the inter lobar to arcuate artery and vein to undergo filtration. It exits thru renal vein, while the filtrate exits thru the ureter.
   1. Glomerulus View
2. Anatomy of Tubules

   Nota:

   • Consists of 2 types of nephrons: Cortical 75% and juxtamedullary which is the other 25%.

Nota:

• Comes in 3 basic steps 1. Filtration 2. Add, the efferent tubules actively secrete stuff across the cellular membrane 3. Reabsorption by the efferent tubules.

1. Types of Flitrations

   Nota:

   • A. Filtered but nor reabsorbed/secreted B. Some of them is reabsorbed C. All of them are reabsorbed. D. All of them are filtered and secreted out.

Nota:

• Blood flow is 1200ml/min in males 20-25% of resting cardiac output. Renal Plasma Flow = Renal blood flow (100 - Haemotocrit)/100

1. Pressure in vessels

   Nota:

   • Experiment done with rats, but the study is similar to humans Cjanges in afferent or efferent arteriolar tone causes changes in renal blood flow. Q = P/R Hence if perfusion pressure is constant. Constriction in arterioles will lead to fall in RBF Dilation of arterioles will lead to rise in RBF
2. Autoregulation

   Nota:

   • Changes with pressure to keep blood/fluid pressure constant. it changes tone of arterioles.
3. Factors influencing RBF

   Nota:

   • override autoregulation Includes: Angiotensin II Vascular-arteriolar vasoconstriction. Renal vasoconstriciton. proximal sodium reabsoprtion. constraction of mesangial cells. Adrenal-aldosterone release. Neural, facilitate sympathetic activity, inhibits vagus, increase ADH and ACTH dipsinogen. CathecholaminesAntidiuretic Hormones (ADH)

Nota:

• rate of formation is Glomerular filtration rate, which normal values are 125ml/min for males or 180L/day.

1. Filtration Barrier
2. Typical Pressures

   Nota:

   • Efferent end : I.e has higher pressures as water is filtered out and left with the proteins.
3. How to change GFR

   Nota:

   • Change in renal blood flow. Change in PGc. Change in Pt: like kidney stone. Change in plasma protein concentration

Nota:

• FIltration fraction = GFR/RPF (renal plasma flow)