The Excretory System Flashcards
excretory system functions
To get rid of wastes
To eliminate useless by-products excreted from cells
To prevent and eradicate harmful chemical build-ups
To maintain a steady, balanced chemical concentration in the body.
parts make up the excretory system
The kidneys, bladder, ureter, urethra, and the renal artery and vein.
Ureter
This tube expels urine from the bladder out the body.
Its outer layer is an elastic-fibre coat for stretching when filling.
The middle layer is smooth muscle which helps maintain the resting-closure mechanism. It also provides pressure when expelling.
An inner epithelial lining keeps the walls moist and protected.
The sphincter muscle at the end controls the expelling and prevents leaking
kidney
Unfiltered blood enters the kidney through the renal artery.
It passes through many, many nephrons where it is filtered.
The glomerulus inside each nephron sends the filtered blood to the renal vein which it is returned to the blood supply.
The tubule collects the waste products (urine) and sends it through the ureter to the bladder.
Bladder
This is a hollow organ which is held in place by ligaments attached to other organs and pelvic bones.
it collects and stores urine
when it fills with urine it expands and smooths out
The middle layer is made of connective tissue with elastic fibres which supports the mucous membrane.
The inner layer is smooth muscle which relax as the bladder fills and contracts during urination.
Birds Excretory System
have 2 kidneys, each with a ureter which carries the urine made by the kidneys to the cloaca for expelling out the body. Birds do not have a bladder.
mammals Excretory System
kidneys perform the filtering of blood to absorb useful elements and collect waste. When the waste reaches the cloaca, it is moved to the large intestine by reverse peristalsis for extra absorption of water. By the time the waste is ready to be excreted, it is a white paste of uric acid.
Descending Limb
permeable to water. Water leaves the nephron by osmosis and is reabsorbed. As much water as the body needs is reabsorbed.
Ascending Limb
permeable to ions. Tissues around the loop have a high concentration of water. Towards the top of the limb sodium and chlorine is actively pumped out.
Distal tubule
final reabsorption of ions and water occurs. ADH affects the amount of water reabsorbed.
Loop of Henle
An anti-diuretic hormone (ADH) is released by the pituitary gland and received by the kidneys. It increases the amount of water reabsorbed in the kidneys. This helps to maintain homeostasis.
uric acid
birds convert nitrogenous waste to insoluble uric acid, which is nearly non-toxic. though it uses more energy to make than urea, it requires less water in the body and is lighter for flight.
nephritis diseases
inflammation of the kidneys which leads to problems filtering the blood effectively
causes - disease, medication, or disorders
symptoms - weight loss, protein in the urine, increased thirst, increased urination and vomiting
liver cirrhosis diseases
is where scar tissue affects normal liver function. This can stop the liver from functioning causing liver failure. This would result in a toxic chemical build-up.
Causes - damage to the liver from diseases, medication, or toxins. infection of hepatitis c. An excess fat build-up in the liver.
Symptoms - loss of appetite, weight loss, vomiting, diarrhoea, lack of energy, an increase in urination
Treatment- healthy diet, exercise, treatment of underlying conditions
