Excretory system

define excretion.

removal of wastes of metabolism

describe the functions of the organs of the excretory system; lungs, liver, sweat glands, kidneys.

Lungs - excrete carbon dioxide from cellular repsiration (gas exchange)

Liver - processing chemicals into safer forms

sweat glands - excrete salts urea, lactic acid

Alimentary canal – excrete bile pigments

Kidneys – excrete nitrogenous wastes

skin

Sweatglands produce 500 mL of sweat per day

• water, sodium, chloride, lactice acid, urea some drugs

Liver

Role: Processes chemicals into a safer form that can be excreted (deamination)

• Detoxifies alcohol and many other drugs

• Deactivates hormones for excretion by the kidneys

• Breaks down haemoglobin from dead red blood cells to produce bile pigments, which are then eliminated

explain the process of deamination.

Proteins are broken down and used as an energy source if carbohydrates are all used - the breaking down for proteins for energy

1. Removes an animo group (NH2) from an amino acid molecule in the liver by enzyme deaminase,

2. remaining produces carbohydrates which can be stored as glycogen or fats or broken down for energy (cellular respiration)

amino group (NH2) is released as Ammonia (NH3) which is toxic to cells. liver will rapidly convert ammonia into urea which is less toxic and can be excreted via kidneys in urine or via sweat glands in sweat

Aminno acid + oxygen ——→ ammonia + carbohydrate

Deaminase

Ammonia + carbon dioxide + energy → urea + water

outline the organs of the urinary system.

Kidney (2) - filters blood

ureter - carries urine from kidney to bladder

bladder - stores urine

urethra - carries urine from the bladder to the exterior

Function of kidney

Rid the body of wastes - nitrogenous wastes e.g urea, uric acid and creatinine

describe the structure of a kidney.

Pair of organs

• located in abdomen,

• primary excretory organ

• apart of urinary system

Renal capsule – tough fibrous layer surrounding the kidney

Renal artery – transports blood into the kidney

Renal vein – transports blood away from the kidney

Cortex – outer part of kidney

Medulla – inner part of kidney

Column – extension of the cortex that divides the medulla into pyramids

Pyramid – section of the renal medulla

Calyces – collect urine from pyramids

Renal pelvis – cavity that collects urine before it goes to the ureter