Introduction

Question 1

What are the functions of the kidneys?

Answer 1

Regulation: control the concentration of key substances in extracellular fluid
Excretion: excretes waste product
Endocrine: synthesis of renin, erythropoietin, prostaglandins
Metabolism: active form of vitamin D, catabolism of insulin, PTH, calcitonin

Question 2

Where are the kidneys?

Answer 2

Retroperitoneal
Left is higher because liver shoves right kidney down a bit
T12-L2/3

Question 3

Where do the ureters run?

Answer 3

Along the tips of transverse processes and along transverse sacroiliac joint
Enter bladder around level if ischial spine

Question 4

What artery and what vein supply the kidneys?

Answer 4

Renal artery and real vein

Question 5

What is the calyx?

Answer 5

A cup that catches urine that filters down into pelvis and then ureter.
We have minor and a major calyx’s.

Question 6

What is the parenchyma made from?

Answer 6

The cortex and the medulla

Question 7

Where are the renal pyramids?

Answer 7

In the medulla

Question 8

What is the function unit of the kidney?

Answer 8

A nephron - this is a filter unit connected to a long tube for reabsorption. There are 1.5million in each kidney.

Question 9

List the parts of the nephron

Answer 9

Glomerulus -filter
Proximal convoluted tubule - in cortex
Loop of Henle - dips in and out of medulla
Distal convoluted tubule - in cortex
Collecting duct - passes through medulla to pelvis

Question 10

What is the rough electrolyte composition of intracellular fluids?

Answer 10

High K+
Low Na+
Many large organic anions

Question 11

What is the rough electrolyte composition of extracellular fluids?

Answer 11

Low K+
High Na+
Main anion Cl- and HCO3-

Question 12

What happens if the kidneys fail to control ECF?

Answer 12

Changes in BP, tissue fluid and cell function

Failure to control ECF osmolarity - cells shrink or swell

Question 13

What is the difference between osmolality and osmolarity?

Answer 13

Osmolality = solute per Kg of solvent 
Osmolarity = number of osmoles of solute per L

Usually similar as at 1Lsquared = 1Kg

Measured in mO

Question 14

What must the kidney do?

Answer 14

Control volume
Control osmolarity
Control pH
Excrete some waste products

Question 15

What happens in the glomerulus?

Answer 15

Filtration
Water, electrolytes and small molecules forced through it by constant filtration press in capillaries
Specialised circulation maintains filtration pressure which determines the glomerular filtration rate.

Question 16

What happens in the PCT?

Answer 16

Main site for resorption
60-70% of na and water
80-90% of potassium
90% of bicarb
100& of glucose and amino acids.
Water follows osmotic gradients so filtrate remains isotonic with plasma
Reabsorbed materials leave by peritubular capillaries.

Question 17

What happens in the loop of Henle?

Answer 17

Reabsorption and creates a gradient of increasing osmolarity in the medulla by counter current. This allows the formation of concentrated urine if water has to be conserved.

Question 18

What happens in the DCT?

Answer 18

Variable reabsorption of electrolytes and water as fluid leaving loop of henle is hypotonic.
DCT removed more Na and Cl and actively secretes H+
Water may / may not follow - if not, large volumes of dilute urine formed (Diuresis)

Question 19

What happens in the collecting duct?

Answer 19

Removes water to create low volume of conc urine. Occurs as:
CD passes though high osmolarity in medulla created by loop of henle
Water crosses epithelium and leaves urine creating low volume of conc.

Question 20

What controls Na recovery?

Answer 20

Renin-angiotensin system.

This controls the ECF volume

Question 21

What controls water recovery?

Answer 21

ADH

This controls the permeability of DCT and collecting duct to water which, in turn, controls ECF osmolarity.