FULL TOPIC 2: ORGANISATION

Where is bile produced?

Liver

Where is bile stored?

Gallbladder

What does bile do?

Neutralises hydrochloric stomach acid and emulsifies fats (gives bigger surface area for the enzyme lipase to work on - makes digestion faster)

What is relationship between the bile from the liver and the hydrochloric acid in the stomach?

Hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine. Bile is an alkaline - it neutralises the acids and makes the conditions alkaline. The small intestine enzyme works best in alkaline conditions

What does the stomach do?

-It pummels the food with its muscular walls

-It produces pepsin (protease enzyme)

-It produces hydrochloric acid to kill bacteria and give the right pH for pepsin to work

What does the Pancreas do?

It produces amylase, protease and lipase then releases them into the small intestine

What does the small intestine do?

It contains protease, amylase and lipase to complete digestion. Digested food is absorbed into the blood.

What does the rectum do?

Stores the faeces

What does the large intestine do?

Absorbs excess water from food

What does the gallbladder do?

Stores bile before it's released into the small intestine

What does the live do?

Produces bile

What do the salivary glands do?

They produce amylase in the saliva

Enzyme

A type of protein that acts as a biological catalyst to speed up reactions

Why do we produce enzymes?

They reduce the need for high temperatures and we only have enzymes to speed up the USEFUL chemical reactions

What is the lock and key model?

The active site of the enzyme changes shape a little as the substrate binds to it to get a tighter fit: induced fit model of enzyme action.

What causes enzymes to denature (the enzymes active site changes shape, so the substrate won't fit)?

Heat, pH - they need to optimum temperature or optimum pH

Equation for rate of reaction

Rate of reaction = Amount of reactant used or amount of product formed / Time

What molecules do digestive enzymes break down?

Starch, proteins, fats

Where is amylase made?

Salivary glands, pancreas, small intestine

What is amylase (starch) broken down into?

Glucose, maltose

Where are proteases made?

Stomach, pancreas, small intestine

What is protease (proteins) broken down into?

Amino acids

Where are lipases made?

Pancreas and small intestine

What is lipase (lipids) broken down into?

Glycerol and fatty acids

What does the circulatory system do?

carries food and oxygen to every cell in the body, to also carries waste to be removed from the body

What is the circulatory system made up?

heart, blood vessels, blood

What is the first half of the circulatory system in the heart?

the right ventricle pumps deoxygenated blood to the lungs to take in oxygen, the blood then returns to the the heart

What is the second half of the circulatory system in the heart?

the left ventricle pumps oxygenated blood around all the other organs of the body, the blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped to the lungs

Why does the heart have valves?

prevent backflow of blood

How does the heart use it four chambers?

1) Blood flows into the left atrium from the pulmonary vein

2) The left atrium contracts pushing the blood into the left ventricle

3) The ventricle contracts forcing the blood into the aorta and out into the lungs

4) The blood from the lungs the flows into the vena cava

5) the right atrium contracts pushing blood into the right ventricle

6) The right ventricle contracts forcing the blood into the pulmonary artery and out the heart

What is your resting heart rate controlled by?

A group of cells in the right atrium wall that act as a pacemaker

How do those cells act as a pacemaker?

Cells produce small electrical impulses which spreads to the surrounding muscle cells making them contract

Why is an artificial pacemaker used?

To control heartbeat if the natural pacemaker cells don't work properly (irregular heartbeat)

Where is the artificial pacemaker located?

A device implanted under the skin and has a wire going to the heart.

How does the artificial pacemaker work?

Produces an electrical current to keep the heart beating regularly

What types of blood vessels are there?

Arteries - these carry the blood away from the heart

Capillaries - these are involved in the exchange of materials at the tissue

Veins - these carry the blood to the heart

Adaptations of arteries

Thick, strong, elastic walls to withstand pressure.

What do the capillaries do?

Carry the blood close to cells to exchange substances with them

Adaptations of capillaries

Permeable walls (for diffusion), one cell thick walls (shorten diffusion distance)

What is a vein?

A vessel that carries blood to the heart

Why are the vein walls thinner than the arteries?

The blood is at a lower pressure

Why does the vein have a bigger lumen than the artery?

Help the blood flow despite the lower pressure

Why do veins have valves?

prevent back flow of blood

Calculate the rate of blood flow

Rate of blood flow = volume of blood / number of minutes

What is blood?

A tissue

What is blood made up of?

Red blood cells, white blood cells, platelets, plasma

What is the job of the blood?

Provide oxygen and nutrients to organs, huge transportation system

What is the job of red blood cells?

To carry oxygen from the lungs to all the cells in the body

What is the shape of a red blood cell?

biconcave disc = large surface area for absorbing oxygen

What adaptation allows red blood cells to carry more oxygen?

Lack of a nucleus

What is haemoglobin?

A red pigment that binds to oxygen in the lungs to form oxyhaemoglobin

What do white blood cells do?

Fight infection

What are the white blood cells that engulf pathogens called?

Phagocytes

How do white blood cells fight infection?

Produce antibodies + antitoxins to neutralise toxins produced by microorganisms

What do white blood cells have that red blood cells don't?

A nucleus

What are platelets?

Small fragments of cells with no nucleus

What do platelets do?

Help the blood clot at a wound - to stop all your blood pouring out and to stop microorganisms getting in

What does a lack of platelets cause?

Excessive bleeding and bruising

What is plasma?

Pale straw-coloured liquid that carries everything in blood

What does plasma carry?

• Red and white blood cells

• Platelets

• Nutrients, glucose and amino acids

• Carbon dioxide, from the organs to the lungs

• Urea, from the liver and kidneys

• Hormones

• Proteins

• Antibodies and antitoxins, produced by the white blood cells

Test for sugars (glucose) (biscuits, cereal, bread)

Benedict's test = heated water bath (75°C)

What is the result for the Benedict's test?

From blue to green, yellow, brick red (depending on the amount of sugar)

Test for starch (carbohydrase) (pasta, rice, potatoes)

Iodine = gently shake

What is the result for the Iodine test?

browny-orange, black/blue black

What is the test for proteins (meat, cheese)

Biuret test (gently shake)

What is the result for the Biuret test?

blue to purple

What are cardiovascular diseases?

Diseases of the heart and blood vessels - non-communicable

Give an example of a cardiovascular disease

Coronary heart disease

What is coronary heart disease?

The coronary arteries that supply blood to the muscle of the heart gets blocked by a layer of fatty material = arteries narrow, blood flow restricted, lack of oxygen = heart attack

What is a stent?

A tube that is inserted inside arteries, to keep them open, to make sure blood can pass through them

Pros of a stent

• lowering the risk of a heart attack

• effective for a long time

• recovery time from surgery = quick

Cons of a stent

• risk of complications during surgery = heart attack

• risk of infection from surgery

• risk of patient developing a blood clot near the stent = thrombosis

What is cholesterol?

An essential lipid, too much of a certain type of cholesterol (LDL cholesterol) can cause health problems

What can having too much bad cholesterol do?

Fatty deposits to form inside arteries = coronary heat disease

What are statins?

Drugs that can reduce the amount of ' bad ' cholesterol present in the blood stream

What do statins reduce the risk of?

Stroke, coronary heart disease, and heart attacks

What type of cholesterol do statins increase?

Beneficial type of cholesterol (HDL cholesterol)

What other potential benefit do statins have?

May also prevent other diseases

What is a disadvantage of statins related to their usage?

They are a long-term drug that must be taken regularly.

What is a risk associated with taking statins?

There is a risk of forgetting to take them.