Urinary System- Microanatomy & Physiology

What is the basic functional unit of the kidney?

nephron

Location of the nephron?

• renal cortex

• renal medulla

Role of the nephron?

• filtrate

• reabsorption

• secretion

• urine concentration

What forms part of the nephron ?

• Renal corpuscle: Glomerulus, Bowman’s capsule 

• Proximal convoluted tubule 

• Loop of Henle

• Distal convoluted tubule 

Where is the renal corpuscle located and the functions?

Location: in the cortex

Function: filter blood and create ultrafiltrate that will become urine 

The blood pressure in the glomerular causes ?

and

what is formed in the glomerules?

• the filtration of blood 

• ultrafiltration is formed here which then enters the bowman’s capsule 

In the fenestrations, what keeps blood cells and large proteins in the blood from being filtered?

glomerular endothelium 

In the glomerular filtration rate (GFR), how much of plasma is removed from circulation spam time?

about 25% plasma is removed every minute 

What is contained in the Bowman’s capsule?

and what does it capture?

It captures the ultrafiltrate from the glomerulus 

the podocytes and the “foot processes” assists further in filtration 

From the Bowman’s capsule, what is the capsular space?

the space between the visceral and parietal layers that collect filtrate 

What is the direction of blood that enters and exits the kidneys?

Blood enters thru renal arteries → get filtrate by nephrons → exits thru the renal veins 

What is different from afferent and efferent arteriole?

Afferent arteriole: brings blood IN to the glomerulus, increases blood pressure, much wider

Efferent arteriole: carries blood OUT

What does peritubular capillaries allow?

allows oxygen exchange, reabsorption, & secretion

What part of the nephron is where most reabsorption occurs?

• Renal corpuscle: Glomerulus, Bowman’s capsule 

• Proximal convoluted tubule 

• Loop of Henle

• Distal convoluted tubule

Proximal convoluted tubule 

• has brush border 

What percentage does reabsorption occurs in the proximal convoluted tubule? 

and 

What are reabsorbed?

About 60%

• ions

• water

• nutrients 

What is the structure of the Loop Henle?

descends from the cortex to the medulla

and 

back to the cortex 

What happens in the Loop of Henle

• NA and CL and water are reabsorbed

In the distal convoluted tubule (DCT), what is the role of aldosterone?

the aldosterone increases NA reabsorption and K excretion

What is the role of collecting ducts?

and 

important things happening here?

carry out tubular filtrate thru medulla to calyces and empty into renal pelvis

• ADH

• aldosterone

• acid-base balance 

What are the hormonal influences on nephron?

and 

what do they do?

• ADH= increase water reabsorption 

• Aldosterone= increases NA and CL absorption & K excretion

• PTH= increases calcium reabsorption

• Calcitonin= increases calcium excretion