Excretory System & Osmoregulation

• Excretory System definition is osmoregulation

Terms

• Excretion is the body's waste product removal of metabolism, where waste has been made by the body itself.
• Egestion (defecation) is the removal of undigested food from the gut.
• Material taken into the gut through the mouth is not regarded as excretion.
• Osmoregulation is based largely on the controlled movement of solutes between internal fluids and the external environment.
• Osmoregulators expend energy to control water uptake and loss in hyperosmotic or hypoosmotic environment.

Waste Products

• Reaction occurring in the body form products which are not used and thus called waste products.
• Waste products are harmful or toxic if allowed to accumulate in the blood and needs to be removed quickly.
• CO2 makes the cytoplasm in cells more acidic which can interfere with other chemical reactions.
• Too much water makes blood and cytoplasm dilute causing cells to swell.

Excretory Organs

• Accessory Excretory Organs include the Lungs, Skin, Liver, and Large Intestine
• Main Excretory Organs include the Kidneys.

Excretory Organs in Humans

• The lungs excrete carbon dioxide and water vapor during expiration.
• The skin secretes water, urea, and salts as sweat and excretes heat.
• The kidneys excrete water, nitrogenous waste, and salts as urine.
• The liver excretes bile pigments and makes nitrogenous waste.

Kidney

• The renal artery takes blood into the kidney, while the renal vein drains filtered blood away.
• Renal medulla is the layer of tissue surrounding the renal pelvis
• Renal cortex is the layer of tissue to the outside of the renal medulla
• The renal pelvis drains urine into the ureter.
• The ureter is a tube that takes urine to the bladder.

Kidney

• Part of the urinary system, it is a main excretory organ in humans.
• Humans have 2 kidneys.
• They are reddish bean-shaped organs, each about 4-5 inches long.
• Located in the abdominal cavity just above the waist, behind the liver.
• The left kidney lies slightly higher than the right one.
• Kidneys remove excess water and nitrogenous waste from the blood also regulate water amount.

Structure of the Urinary System

• Urinary bladder acts as a temporary storage place for urine.
• Ureters send urine to the bladder from the kidneys.
• Urethra is the tube-like structure that carries urine from the urinary bladder to the outside of the body.
• Renal arteries transport blood with waste to the kidneys. Humans have 2 renal arteries.
• Renal veins returns useful nutrients back into the bloodstream after filtering. Humans have 2 renal veins in humans.
• Urethral Sphincter controls the release of urine from the bladder.
• Kidneys remove excess water and nitrogenous waste from the blood. Humans have 2 kidneys.