B4 Organisation of animals and plants

A blood vessel that carries blood away from the heart at relatively high pressures It has thick muscular walls and a small lumen

Small thin walled blood vessel that connects arteries to veins Walls are one cell thick-short diffusion distance

Blood vessel that returns blood to the heart at relatively low pressures Thin walls Valves Large lumen

When breathing in air flows in through the trachea Through the bronchi to each lung, then to the alveoli The diaphragm and intercostal muscles contract when we breathe in and relax when we breathe out

Short diffusion pathway Huge surface area Good supply of oxygen and blood

The larger chambers in the heart The right ventricle pumps blood to the lungs The left ventricle pumps blood to the rest of the body

The smaller chambers in the heart These fill with blood from the vena cava and pulmonary vein then pump the blood into the ventricles

The artery leaving the left ventricle Sends oxygenated blood to the rest of the body

The main vein that brings deoxygenated blood back to the heart (The right atrium)

The artery that leaves the right ventricle to carry blood to the lungs

The vein leading from the lungs back to the heart (left atrium)

Red blood cells White blood cells Plasma Platelets

The liquid part of the blood which all the blood cells are suspended in It transports: Carbon dioxide from the organs to the lungs, urea from the liver to the kidneys

Biconcave shaped cells that contain haemoglobin which oxygen can bond to for transportation Very large surface area for diffusion of gases and can squeeze through capillaries

Cells in the blood that fight infection caused by pathogens-Form part of the bodies immune system M Lymphocytes-Synthesise antibodies Phagocytes-Engulf and digest pathogens

Fragments of cells Their role is to initiate the process of clotting at a wound, this blocks the wound in the blood vessel and prevents excess blood loss

Right atrium

Smoking Obesity High blood pressure

Stents can be used to open up the blood vessel A metal mesh with a tiny balloon inside is inserted into the artery and the balloon is inflated which opens up the blood vessel and allows the blood to flow freely

Blood flow is reduced

Biological valves-Made from valves taken from pigs of cattle Mechanical valves-Made from polymers and titanium

Pros- They do not damage red blood cells Cons- Can become hardened after several years May have to be replaced Risk pf rejection

Pros- Strong and durable, wont have to be replaced Cons- Damage red blood cells Require anti clotting drugs for the rest of patients life Some people say they can hear the valves open and close

Type of plant tissue that covers the surface of a plant