Question

(Please be neat when labeling the sketch) Describe the flow of fluid through a nephron and to the external environment. Include a simple labelled sketch with your description

Answer 1

Pair of kidneys constitute nephrons which forms urine. Passage of urine flow is from urinary bladder to ureter.
The formation of urine starts as blood will reach to malphigian corpuscle which  is made of glomerulus and Bowmans capsule.
Filtration of blood plasma occur in Bowman capsule.
Now filtrate is passed to proximal convoluted tubule, here reabsorption of amino acid, glucose and water takes place.
Remaining fluid or blood plasma will pass to Loop Of Henle. Here absorption of potassium and sodium occurs.
Fluid will now enter Distal Convoluted Tubule, the region where tubular secretion occurs.
Next, the fluid will enter the collecting duct, the maximum of water is reabsorbed here and the concentrated urine is formed.
All the collecting ducts together will pour their urine into Duct of Bellini
Minor calyx is the region where urine is collected after this it will collect in major calyx
Both these calyces will give rise to pelvis that will further open into duct called ureter. From both side, the ureter will pour urine into urinary bladder.
Thus when the urinary bladder is full of urine, our brain will recieve signal and a feeling to micturate occurs because the stretch receptors will function and work in generating the signal.
Urethral opening is controlled by the sphinters to void the urine so that it cannot come outside the body.