The Excretory System Flashcards
What is the excretory system ?
A system which is designed to remove waste products from the body.
How are waste products removed from the body in mammals ?
Urine
How are waste products removed from the body in reptiles and birds ?
Uric acid
What is excretion ?
The removal of metabolic waste products from the body
What is Elimination ?
The removal of indigestible foods from the body.
What are the 3 sections of which the kidney can be divided into ?
Pelvis , Medulla and Cortex
Name the functional units within the kidney
Nephrons
What is the function of the cortex section of the kidney ?
A space for the arterioles and venules from the renal artery and viren to perfuse to the nephrons of the kidney.
What is the function of the medulla section of the kidney ?
Regulate the concentration of urine
What is the function of the Ureters ?
To carry urine from the kidney to the bladder
What is the structure of the Ureters ?
Made up of a tube of smooth muscle which forces the urine into the bladder via the use of peristaltic waves.
What are the main functions of the bladder ?
Storage of urine before excretion
What is the structure of the bladder ?
Built up of transitional epithelium which allows for stretching
Folds of material flatten out when it is full
Covered with a smooth muscle to help with expelling of urine.
Exit is sealed by a sphincter
What is the function of the urethra ?
Carries urine from the bladder to the exterior of the body.
Describe the structure of the urethra
Made of fibrous tissues and muscle and is lined with mucous membranes
In males it runs through the penis to the environment
In females it is shorter and will lead directly to the outside or will joint the vagina
How does the avian excretory system differ to the mammalian excretory system ?
Birds do not have a bladder and they have an excretory system which contains two kidneys a ureter and a colcaca. Birds have a ureter and mammals have a urethra.
How is water absorption within the body controlled ?
Water absorption is controlled by ADH ( antidiuretic hormone) in the blood.
What is ADH (antidiuretic hormone) ?
A hormone which causes the membrane in the collecting duct to become more permeable to water and therefore this allows for more water to be absorbed resulting in the formation of concentrated small amounts of urine.
How is the water potential of the blood detected ?
Sensory cells called osmoreceptors in the hypothalamus
What happens when the water potential in the blood is low ?
Water moves out of the osmoreceptors by osmosis which causes the cells to shrivel. Which causes ADH to be made which is then released into the bloodstream by the posterior pituitary gland .
