Topic 4: Organising animals and plants

The circulatory system

• The heart

• Blood vessels

• Blood

What does blood carry

• Oxygen

• Glucose

• Water

• Hormones

• Carbon Dioxide

• Urea - Waste

Components of Blood

• Red Blood cells

• White Blood cells

• Platelets

• Plasma

Red Blood Cells

• Red blood cells contain haemoglobin to carry oxygen

• They have a large surface area for absorbing oxygen

• No nucleus

White Blood Cells

• White blood cells helps your body defend against pathogens

• Lymphocyte - make antibodies

• Phagocyte - goes round eating bacteria in the body

• Have a nucleus

Platelets

Platelets help your blood clot and help the body form scabs to help wounds heal

Plasma

• Fluid of blood, and helps with blood clotting

• Plasma carries 4 substances: water, glucose, hormones, CO2

The process of blood clotting

Blood clotting is the process that stops bleeding when you get hurt

• First, blood vessels tighten to reduce blood flow

• Then tiny blood cells called platelets, stick to the injury + form a plug

• Then a series of proteins in the blood work together to create fibrin, which forms a net that traps blood cells + helps the clot get stronger

• This clot helps close the wound, and once the vessel is healed the clot breaks down naturally

blood under a light microscope and how to recognise components

Red blood cells - pink

Platelets - pale pink

White blood cells cytoplasm - pale blue

White blood cells nuclei - magenta

Blood Vessels

Vein:

• Transports blood from the body’s organs back to the heart

• They have thin walls + contain valves that stop the blood from flowing backwards

• Blue, Deoxygenated blood

Capillary:

• Allows substances to diffuse to/from blood/tissues

• Connect the arteries to the vein

Artery:

• Transports blood away from the heart at high pressure

• They have thick walls to handle the high pressure from the heart’s pumping action

• Red, Oxygenated blood

The heart diagram

Vena Cava Function

• Deoxygenated

This vein carries blood into the heart from the body

Aorta Function

• Oxygenated

This artery carries blood around the body

Pulmonary vein and Pulmonary artery function

Pulmonary vein -

• oxygenated

This vein carries blood into the heart from the lungs

Pulmonary artery -

• Deoxygenated

This artery carries blood to the lungs

Left atrium and Right atrium function

Left atrium -

• Oxygenated

Pumps blood from the lungs to the left ventricle (has thin walls)

Right atrium -

• Deoxygenated

Pumps oxygen to the right ventricle (has thin walls)

Valves Function

• Oxygenated and Deoxygenated

Stop blood going backwards

Left ventricle and Right ventricle Function

Left ventricle -

• Oxygenated

Pumps blood around the body (has thick walls)

Right ventricle -

• Deoxygenated

Pumps blood to the lungs, where gas exchange takes place (has thick walls)

What does the heart do

The heart is an organ that pumps blood around the body in a double

circulatory system.

How does the heart uses its four chambers to pump blood around the body

1. Blood flows into the atria from the vena cava and the pulmonary vein

2. The atria contract, pushing the blood into the ventricles

3. The ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart

4. The blood then flows to the organs through arteries, and returns through veins

5. The atria fill, and the whole cycle starts again over

Explain why an irregular heartbeat is detrimental to health

An irregular heart can make the heart less effective at pumping blood, which means the body doesn’t get enough oxygen. Which can lead to problems like stroke, heart failure, dizziness + fatigue. In severe cases, it can cause sudden heart failure. Treatment is important.

Different treatments for heart problems + their advantages and disadvantages

Advantages and disadvantages

Lifestyle Change:

• No surgery or medicine needed

• Helps prevent further heart problems

• Improves overall health

• Requires effort + consistency and takes time to show results

Medications:

• Easy to take (pills or injections)

• Quickly relieves symptoms

• No surgery needed

• May have side effects

• Might be taken long-term

Coronary Artery Bypass Surgery:

• Can solve serious artery blockages long-term

• Improves quality of life

• Long-term recovery

• Risk of infection

Implantable devices (pacemakers, defibrillators):

• Helps control heart rhythm

• Can prevent heart failure

• Requires surgery to implant

• May need replacements or adjustments over time

Heart transplant:

• Life saving

• Improves long-term health

• Donors are hard to find

• Requires medication to prevent (ejections which can have side effects)

What happens in coronary heart disease

In coronary heart disease, layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle. Stents are used to keep the coronary arteries open. Statins are widely used to reduce blood cholesterol levels, which slows down the rate of fatty material deposit.

Stents and Statins

Stents:

• Stents are small, tube-like dives used to keep passageways, like blood vessels, open. They are often used in cases of narrowed or blocked arteries to improve blood flow. (they can be made from metal)

Statins:

• A Statin is a medicine that lowers bad cholesterol in your blood, it helps prevent problems like heart attacks + strokes by stopping your body from making too much cholesterol

Stents and statins advantages and disadvantages

advantages and disadvantages

Stents:

• Restores blood flow, relieving symptoms like chest pain

• Quick recovery

• Long-term effectiveness

• Prevents further blockage

• Risk of complications (infection, bleeding)

• Long-term medication

• Re-narrowing of the artery

• Not a cure

Statins:

• lowers cholesterol + reduces heart disease risk

• Well studied + cost-effective

• Reduce inflammation

• Risk of diabetes

• Possible side effects (muscle pain, liver issues)

• Lifelong treatment

• Does not directly treat blockages

Why might people have objections to heart transplants

• Religion + cultural

• Cost

• Fear of rejection

• Medical risks

• Can place too much of a strain on your organs

Artifical and Natural pasemakers

Natural:

The heart has a natural pacemakers called the SA node, located in the right atrium. It sends out electrical signals to start each heartbeat making sure the heart contracts reguarly. This node keeps a normal resting heart of 60-100 bpm which is important for good blood flow

Artificial:

An artificial pacemaker is a small device that helps your heart beat regularly. It uses a battery + wires to send electrical signals to your heart. This makes sure your heart beats at the right speed especially when your natural pacemaker isn’t working well

What are antitoxins

antibiotics