adrenal cortex

posterior pituitary

hypothalamus

zona glomerulosa cells

autoregulatory mechanisms

interstitial fluid countercurrent gradient

constriction of the efferent arteriole

counter current mechanism

is produced by the direct action of the enzyme renin on the protein angiotensinogen

suppresses the secretion of aldosterone from the adrenal cortex

is activated by increases in blood pressure or volume

stimulates anti-diuretic hormone release from the posterior pituitary

Water will move freely between the intracellular fluid and ECF compartments decreasing osmolarity and increasing the volume of both.

This is an isosmotic solution so ECF osmolarity will not change.

Intracellular fluid volume does not change.

This is a hypertonic solution so ECF osmolarity will increase.

Inulin is freely filtered, reabsorbed and secreted by the nephron

Inulin is freely filtered and reabsorbed by the nephron

Inulin is freely filtered and secreted by the nephron

Inulin is not metabolised in the body        

Glucose transport by the renal tubules is linked to sodium transport

The distal tubules reabsorbs all of the filtered glucose

The transport maximum for glucose is about 36 mg min-1

Glucose is secreted into the urine in small quantities

More water than sodium has been reabsorbed.  

The fluid is hypo-osmotic.   

A similar percentage of water and sodium has been reabsorbed.

The fluid is hyper-osmotic.

Glomerular capillary hydrostatic pressure plus the glomerular capillary osmotic pressure minus the tubular osmotic pressure.

Glomerular capillary hydrostatic pressure plus the glomerular capillary osmotic pressure minus the tubular hydrostatic pressure.

The sum of the tubular and the glomerular capillary hydrostatic pressures minus both the tubular and glomerular capillary osmotic pressures.

Glomerular capillary hydrostatic pressure plus tubular osmotic pressure minus tubular hydrostatic pressure minus glomerular capillary osmotic pressure.

No change in cell volume

Increased total body water content

Reduced ECF osmolarity

Increased ECF volume