3.74

ADH regulates water content of blood
ADH = Anti Diuretic Hormone 
Found in a part of the brain (Hypothalamus)
Flows through the body until it reaches the kidneys
Has the ability to alter quantity of water in the blood 
Therefore it can make the blood more or less concentrated 
Describe the role of ADH in regulating the water content of the blood.
Targets the collecting duct and makes it more porous 

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2.73 Glucose reabsorbtion

Similarly to the water some of the glucose is also lost
This means that it has to be re absorbed
this is done by the promximal convoluted tubule
If there is glucose in the urine however this means the person has diabetes

2.72 Water re-absorbtion

Ultra filtration sometimes filters out to much water

To prevent water loss the water must be absorbed back

This happens when the water passes along the collecting duct 

The water is removed from the filtrate and is absorbed back into the blood vessels 

2.71

Nephron carries out filtration of blood

Ultra filtration = filtration of molecules

Blood comes in and out of the arteriole and causes high pressure

This forces the plasma out of the blood vessel

The blood is filtered by utilizing high pressure 

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2.70 Structure of the Nephron

The lighter outer area is called the cortex

The dark shade in the middle is called the medulla

The light spot in the center is called the pelvic and is wear urine is stored

The bowman’s capsule is the dead end of a tubing structure in the kidney

The tubing structures are made up of twisted sections

A tight knot of blood vessels is known as the glumerous 

Their are millions of Nephrons in a single kidney

They give the kidney its different colour tones 

2.69

·         The urinary system includes the kidneys, bladder, urethras and ureters.

·         Each component has its own individual blood supply

·         The ureters links the two kidneys to the bladder and transfers the urine

·         The bladder is then linked to a structure called the urethra which carries the waste out of the body.

2.68b

·         The kidney carries out a process called osmoregulation

·         Osmo: osmosis & regulation: control

·         Cells in the body are ideally ISOTONIC with the tissues around them

·         This means that the amount of water passing in and out of the cells are equal and therefore the cells stay the same size

·         However the blood that circulates in and out of the cell maybe of a different concentration and therefore cause a HYPERTONIC or a HYPOTONIC solution.

·         Both of these solutions could harm the cells and therefore the most desirable option is an ISOTONIC solution.

·         This is why the composition of the blood has to be controlled and this is done so by the Kidney

·         The kidney can control the composition of the blood by removing excess Water and Salt from the blood and excreting it.

·         By controlling the content of water and salt in the blood the kidney can keep the cells ISOTONIC at all times.

Osmoregulation: Is when the composition of the blood is controlled by the kidneys through excreting waste water and salts to keep the cells in the body Isotonic.  

2.68a:

• The kidneys job is to excrete out waste substances
• Urea is composed of nitrogen which can be toxic to the body
• Nitrogen is usually found around the body in the form of amino acids, these are generally good for the body but can be dangerous when found in large quantities (excess amino acids)
• Amino acids are broken down in the liver to form Urea and is then circulated to the kidneys where the urea is FILTERED out from the rest of the blood stream
• The urea is then added with water to form urine which is then passed down to the bladder where it is ready to be removed
• The filtered blood then returns to the body free of the toxic urea and nitrogen

2.67b:

• In the human body lungs, kidneys and skin are all organs of excretion
• The lungs excrete Carbon dioxide (CO2)
• The kidneys excrete – Water (H2O), Urea (amino acids) and salts
• The skin excretes – Water & salts (through sweating) as well as a small bit of Urea

2.67a

• A leaf photosynthesizes and by carbon dioxide and water to form Glucose and oxygen
• CO2 + H2O  C6H12O6 + O2
• The oxygen is the waste molecule of the process photosynthesis so the leaf is excreting oxygen as a waste gas
• Respiration is when the leaf uses the glucose with oxygen to produce energy (ATP)
• C6H12O6 + O2  ATP +CO2 + H2O
• In this reaction the molecules that are wasted are carbon dioxide and water and the leaf excretes these out.

2.67a

• A leaf photosynthesizes and by carbon dioxide and water to form Glucose and oxygen
• CO2 + H2O  C6H12O6 + O2
• The oxygen is the waste molecule of the process photosynthesis so the leaf is excreting oxygen as a waste gas
• Respiration is when the leaf uses the glucose with oxygen to produce energy (ATP)
• C6H12O6 + O2  ATP +CO2 + H2O
• In this reaction the molecules that are wasted are carbon dioxide and water and the leaf excretes these out.