Excretion Flashcards
Define excretion
Excretion is the removal of metabolic waste from the body
Briefly explain excretion?
The metabolic processes that take place within the body produce a variety of waste products (CO², ammonia, urea and uric acid)
Accumulation of these waste products within cells have a negative impact on its normal functioning. Excretion is the removal of these waste products.
What are the main excretory organs?
•Skin: produces sweat, which contains water, salts and urea
•Lungs: removes CO² (released from body cells during cellular respiration) and some water
•Kidneys: removes urea, uric acid, ammonia and water
•Large intestine: removes heavy metals
What makes up the urinary system?
The urinary system consists of the two kidneys, two ureters, bladder, urethra and it’s associated blood supply, the renal artery and renal vein.
State the main function of the urinary system
The main function of the urinary system is to maintain homeostasis by regulating the composition, volume and pressure of the blood.
What are Ureters?
Ducts that carry urine from each kidney to the bladder.
What is the bladder?
Located in the pelvic cavity, it serves to store urine prior to urination.
What is the urethra
A tube leading from the bladder to the exterior through which urine is discharged
The kidneys
Reddish brown bean-shaped organ above the waist
Internal structure of the kidneys
Renal cortex- outer reddish part
Renal medulla- reddish-brown region that consists of cone-shaped structures call pyramids (base faces cortex, apex faces calyx)
Renal cortex & pyramids make up functional unit called the Nephron
What happens to urine formed by the nephron?
Drains into papillary ducts which lead into cup-shaped calyces. The urine drains into the renal pelvis, passes down the ureters, enters the bladder and eventually leaves the body via the urethra
The nephrom consists of 2 portions:
The renal corpuscle (Malpighian body) where plasma is filtered
A renal tubule into which filtered fluid passes
