Excretion Lecture Notes

Flashcards about Excretion

Excretion

Occurs outside the body; is the process of discharging wastes from body.

Secretion

Occurs inside the body; is the process of producing a substance.

Excretion

The process of getting rid of metabolic waste.

Metabolic Waste

Chemical process in the body.

Excretion Role

Helps to keep body fluid composition constant and maintain homeostasis.

Metabolic Wastes

Carbon dioxide, water, ammonia, mineral salts, urea, uric acid.

Gout

Arthritis of the big toe related to uric acid.

Origin and Excretory Organ of Ammonia

Breakdown of amino acids in the liver; excretory organ is the kidneys.

Origin and Excretory Organ of Urea

Conversion of ammonia in the liver; excretory organs are kidneys and skin.

Origin and Excretory Organ of Carbon Dioxide

Cellular respiration; excretory organs are lungs, intestines, and skin.

Origin and Excretory Organ of Mineral Salts

Food and water; excretory organs are kidneys and skin.

Function of the Skin in Excretion

Sweat containing urea, salts, and water.

Function of the Anus in Excretion

Intestine & Liver -> Solid Waste -> Egestion (feces).

Function of the Lungs in Excretion

CO2 and H2O; help breakdown Glucose.

Function of the Kidneys in Excretion

Nitrogen waste -> Ammonia -> Urea and Uric Acid -> Liquid form (urine).

Four Ways You Lose Water

Urine, sweat through skin, respiration through lungs, egestion via feces.

Three Ways You Gain Water

Drinking fluids, eating food with water content, reactions in the body.

Role of the Liver in Excretion

Accessory organ; excretes cholesterol, steroid hormones, certain vitamins and drugs through bile, but does not excrete outside the body.

Urinary System

Plays a major role in maintaining homeostasis

Four Major Functions of the Urinary System

Excretion of metabolic wastes, maintaining water-salt balance, maintenance of acid-base balance, secretion of hormones.

Excretion of Metabolic Wastes by the Kidneys

Kidneys excrete metabolic wastes (mostly nitrogen based).

Urea

Primary nitrogen waste produced through metabolism.

Wastes Excreted by the Kidneys

Ammonium, Creatinine, and Uric Acid

Urea Formation

Urea is produced through braking down of amino acids which then forms ammonia with help from the liver. Urea is formed when Ammonia and CO2 combine.

Ammonia

Very toxic to cells, therefore converting to Urea makes that nitrogen waste less harmful

Maintaining Water-Salt Balance

Maintaining the Water-Salt balance in the blood.

Salt and Osmosis

Higher the salt content of blood the more ability to cause OSMOSIS – the diffusion of water -- in this case into the blood.

Kidney's Function in Acid-Base Balance

Regulate pH balance in the blood – in a healthy person it should be just about 7.4

Kidneys and pH Monitoring

Monitor by excreting hydrogen ions (H+) and reabsorbing the bicarbonate ions (HCO3) as needed.

Urine's pH

It's near 6 or lower because our diet often contains acidic food

Kidneys and Hormone Secretion

Assist the endocrine system in hormone secretion.

Aldosterone

Responsible for promoting reabsorption of sodium ions (Na+) by the kidneys.

Role of Kidneys in Excretion

Kidneys are the primary organs of excretion, particularly nitrogenous wastes.

Kidneys and Homeostasis

Major organs of homeostasis as they regulate many functions such as water-salt balance and acid-base balance of the blood. As well as secrete hormones.