excretory system notes with video links by aiimiit

1.excretory system in human beings are as fallows
Pair of kidneys
Large intestine
Skin
Nose
Mouth
Ear
Eyes

2.coming to kidneys the parts of kidneys are
Kidneys
Ureters
Bladder
Urethra

3.kidneys
Pair if kidneys are present
Kidneys are filled with millions of nephron
Nephron is structural and functional units of kidneys
Kidneys main functions are as fallows
A.Urine formation
And
B.Osmo regulation(maintainence of salt and water balance into the body)

4.NEPHRON
Structural and functional unit of kidneys is nephron
Nephron helps in urine formation

5.urine formation

Urine formation takes place in 3 stages
A.ultrafiltration
B.selective reabsorption
C.tubular secretion

A.ultrafiltration

Since blood flow under high pressure in arteioles
Some blood gets filtered into bowman's capsule
Because they unable to withstand high pressure
This filtration of blood into bowman's capsule under high pressure is called ultrafiltartion

B.selective reabsorption

Blood when passing through descending tubules,henlees loop,ascending tubules
All the blood which got filtered is reabsorbed back
Leaving behind all wastes like amino acids,urea,uric acid
All these wastes slowly gets settled in tubules

C.tubular secretion

All wastes gets settled in tubules
That is called tubular secretion

All tubules of all neprons slowly drain drop by drop into ureters

Through ureters it enter into bladder

When 250 to 300 ML of urine is accumulated in bladder

We get sensation to pass urine

Passing out of urine is called micturition

Formation of urine occurs in kidneys