Biology B3.P1 Flashcards
Kidneys
-Humans have two kidneys located at the back of the abdominal cavity.
-They are connected to the bladder via the ureters – a long white tube, carrying urine
from the kidneys to the bladder
Why is the kidney needed?
kidney filters waste and excess substances from the blood, forming urine to remove them from the body.
does osmoregulation where, It also helps regulate fluid balance, blood pressure, and important minerals in the body.
Homeostatic organs
Regulates blood pressure through maintaining water levels.
How is urea made?
Made by breaking down excess amino acids in liver.
(process known as deamination)
Hypertonic
More concentrated solutions than in cells.
When a red blood cell is placed in hypertonic solutions the water leaves the cell by osmosis and the cells shrink and the membrane wrinkles.
(Process crenation)
Isotonic
Has the same concentration in cells.
Lysis and crenation do not happen in the body if the kidneys function properly as the kidneys keep the blood concentration isotonic.
Hypotonic
More dilute than solution in cells.
When RBC is in hypotonic solution- the water enters the cells through osmosis and as the volume increases the pressure in the cell membrane bursts (process known as lysis)
Kidneys different parts (P1)
-Renal artery: where blood flows into the kidneys.
-Internal structure of the kidney- is where urea is produced.
-Urethra- releases urine out of the body.
-URETER carries urine from
kidney to the bladder
Internal structure of the kidney (P2)
-Cortex - filters large molecules from the blood (WBC) : contains glomeruli and
convoluted tubules - ultrafiltration and some reabsorption takes place
-Renal vein- takes blood away from kidney
-Pelvis – collects urine
-Medulla - where water, salt and urea are removed from blood: contains loops of
Henle - most reabsorption takes place.
The Kidneys and Urine Production
Kidneys produce urine in a two-stage process
1. Ultrafiltration:
-small molecules and ions, filter out of the blood into renal capsule.
-this process is called ultrafiltration because it filters out molecules
which are much smaller than the particles separated by filters such
as filter paper.
2. Reabsorption:
- molecules and ions which are required by the body are taken back
from the nephron
- ultrafiltration takes place under pressure
Kidneys overall explain (P3)
-The kidneys filter blood and form urine that is stored in the bladder.
(They are located in the lower back)
-Each kidney has outer layer called cortex and an inner layer called the medulla. There are millions of structures called kidney tubules (nephrons) and this is where the blood/ waste products are filtered out.
