Transport In Humans

-Small organist have no problem absorbing oxygen because their surface area is big enough to gain sufficient oxygen for it’s small volume of cells by diffusion -No transport system required because gases can diffuse directly into all tissues because of high surface area to volume ratio -Whole cell surface in contact with the environment

-large organisms (humans)have a relatively small surface area when compared with their large volume of cells -slow rate of diffusion -only outer cells are in contact with the environment, inner cells have no contact with the environment -therefore large organisms have adaptations to increase their surface area

-to compensate we have lungs -circulatory system which will transport nutrients around the body -alveoli have large surface area for gas exchange as they are bumpy and there is lots of them -root hair cells in plants for absorption of nutrients from the soil -small intestine as it’s long and contains vili in its lining to absorb small food molecules

RBC WBC platelets plasma

Structure -biconcave shape for large surface area -produced in bone marrow Function -bonds with haemoglobin and carries oxygen around the body

To defend the body against infections by identifying, attacking and destroying harmful pathogens such as bacteria and viruses

Structure -shape of a plate -no nucleus Function -helps with blood clotting and forming scabs -prevents/stops bleeding

Structure -contains 91-92% water and 8-9% solids Function Helps to recover your body from injury, distribute nutrients, remove waste and prevent infection

Phagocytes- immune cells That surround and kill microorganism, and also protects the body from foreign particles, bacteria by ingesting harmful cells They ingest and digest the pathogens using digestive enzymes in a process called phagocytosis

-produce antibodies in response to antigens on the surface of the pathogen -antibodies are complementary in shape to the antigens -antibodies work in 3 ways 1. Cause pathogens to stick together 2. Mark them for destruction 3. Act as antitoxins

Proteins on the surface of pathogens, these allow human body to identify pathogens as foreign and trigger an immune response

Process by which out body creates defence or antibodies to fight pathogens by purposely being exposed to a non-threatening inactive or dead version of the pathogen (attenuated pathogen which is unlikely to cause harm) but it still contains the same antigen as the actual pathogen which triggers a primary immune response

• You are injected with a vaccine with a small amount of dead or inactive pathogen which still have the same antigen • Which blood cells detect the antigens • White blood cells make antibodies to fit the antigens • The antibodies attach themselves to the inactive pathogens and kill them, aka primary immune response • White blood cells recognise the shape of the antigen • Live pathogen enter the body for the first time (infection) • White blood cells instantly recognise the live pathogens as the have the same antigens as the vaccine and make antibodies immediately - secondary immune response • The antibodies attach themselves and kill the pathogens before they have a chance to make you feel ill, no symptoms

-more muscle contraction -more energy needed -more O2 and glucose -more blood flow -more removal of waste products Which therefore increases the heart rate

Genetics High blood pressure Fatty food Smoking Stress No exercise

More likely to have CHD is your parent have it

Can cause damage to the heart and arteries

Fat can built up in the blood vessels

Raising blood pressure which can cause blood clots Increase heart rate

Raises blood pressure

Regular exercise reduces blood pressure and strengthen the heart

-going towards the body, away from the heart - carries oxygenated blood to the body tissues -high blood pressure -elastic walls -narrow lumen -no valves