2.69

Looking at the structure of the urinary system

2 KIDNEYS – each has a separate blood supply – filtration and excretion

From each kidney there is a tube that leads to the bladder – URETER

Urine then goes down the URETHRA which passes either through the vagina or the penis

2.68b

Kidneys in the process are OSMOREGULATION

To keep blood ISOTONIC

Kidneys control the composition of blood

2.68a

Looking at the excretion of Urea (nitrogen – toxic to the body and cannot be stored) the original form is amino acids. This is the role of the liver and kidneys

Liver – amino acids are broken down and turned into urea. Released into the blood stream where it circulates to the kidneys

Kidneys – will filter urea from blood, it is added to water to form urine, where it collects in the bladder to be excreted (peeing) the filtered blood returns to circulation. 

2.67b

1. lungs – carbon dioxide

2. Kidneys  (x2) – excess water, urea (amino acids), salts

3. Skin – water, salts (sweat),  urea 

2.67a

1. *the leaf* - consider process of photosynthesis (leaf absorbs light energy : carbon dioxide + water -> glucose + oxygen) 

this is anexample of excretion – the release of metabolic waste

2. respiration

Glucose (C6H12O6) + O2 -> enzyme rection -> ATP + carbon dioxide + water

Carbon dioxide ( like water in 1.) is metabolic waster = excretion