What organs play a major part in the urinary system?
The kidneys.
What are the main roles of the kidneys?
Waste excretion, filtering and cleaning the blood, producing urine.
What does the ureter do?
Transports urine.
What does the bladder do?
Stores urine.
What does the urethra do?
Allows urine to exit the body during urination.
What is the kidney full of?
Blood vessels, arteries, veins.
Blood arrives at the kidney via the...?
Renal artery, which splits into many different arterioles.
Where do the arterioles go?
The Bowman's Capsule of nephrons, which removes waste from the blood by pressure ultrafiltration.
What surround the nephron? What do they do?
Capillaries. They take substances in and out of the blood. 'Good' substances get reabsorbed.
What is the renal cortex?
The outer layer of the kidney.
What is the renal medulla?
The inner layer of the kidney.
What is the renal pelvis?
The section of the kidney which connects to the ureter. Nephrons enter and dispose of waste/urine through here.
What is diffusion?
The movement of molecules from an area of high concentration [of the molecules] to an area with a lower concentration.
How does diffusion work in the kidney?
Waste products are in a higher concentration in the blood and are filtered out. Valuable nutrients are reabsorbed.
How do most mammalian urinary systems work?
Water is absorbed through the small intestine where it enters the bloodstream. The kidneys filter the blood and remove waste products before filtering the fluid back in. The waste, urine, then enters the bladder through the ureters where it is stored until the animal is ready to urinate.
How does the bird urinary system work?
Birds kidneys are different to mammalian ones. They have three lobes whilst mammals have bean shaped kidneys.
Birds have two types of nephrons. Mammalian and reptilian.
Their kidneys produce uric acid (rather than urea like mammals) which is a paste-like substance.
They have a cloaca and do not have a bladder. Uric acid travels from the kidneys into the ureter and out of the cloaca.
What is different about animals which live in climates that limit their access to water?
They must absorb as much water as possible in order to stay hydrated.
They filter as much water as possible in order to reabsorb it.
Camel kidneys have a 1:4 cortex to medulla ratio. Their urea comes out as a “thick syrup”.
What does the excretory system of a fish involve?
Their gills, kidneys and bladder.
Filtered blood exits via the...?
Renal vein.
What is the nephron?
The functional unit of the kidney in which filtration takes place.