Organisation

• Cells are the basic building blocks that make up all living organisms.
• The process by which cells become specialised for a particular function is called differentiation.
• A tissue is a group of similar cells that work together to carry out a particular function.
• In mammals examples of tissue include:

  Muscular tissue- contracts to move whatever its attached to

  Glandular tissue- makes and secretes chemicals like enzymes and hormones.

  Epithelial tissue- covers some parts of the body e.g inside of gut
• An organ is a group of different tissues that work together to perform a certain function.
• An organ system is a group of organs working together to perform a particular function.
• Enzymes act as biological catalysts
• Enzymes are all large proteins that are made up of chains of amino acids.
• If an enzyme gets too hot, some of the bonds holding the enzyme together break, changing the active site, becoming denatured.
• All enzymes have an optimum temperature (around 37 degrees) that they work best at.
• All enzymes have an optimum pH that they work best at.
• If pH is too high or too low, it interferes with the bonds holding the enzyme together, changing the active site, causing the enzyme to be denatured.
• Amylase is an example of a carbohydrase.
• Amylase breaks down starch into glucose. It is produced in the salivary glands, the pancreas and the small intestine.
• Protease converts protein into amino acids. It is produced in the stomach, the pancreas and the small intestine.
• Lipase converts lipids into glycerol and fatty acids. It is found in the pancreas and small intestine.
• Bile is produced in the liver and is stored in the gall bladder before released into the small intestine.
• The function of bile is to neutralise the acid from the stomach to allow enzymes in the small intestine to work properly. It also emulsifies fat breaking it into smaller droplets to give it a bigger surface area for the lipase to work on making digestion faster.
• Salivary glands- produce the amylase enzyme in the saliva.
• Liver- Where bile is produced.
• Gallbladder- Where bile is stored.
• Large intestine- Where excess water is absorbed from the food.
• Stomach- Pummels the food with its muscular walls, produces pepsin (protease enzyme), produces hydrochloric acid that kills bacteria, and gives right pH for pepsin to work.
• Pancreas- produces protease, amylase, lipase that is released into small intestine.
• Small intestine- produces protease, amylase, lipase to complete digestion. Also where digested food is absorbed into the blood.
• Rectum- Where the faeces are stored until excreted through the anus.
• The thorax is the top part of your body and is separated from lower body by the diaphragm.
• The lungs are protected by your ribcage.
• The air you breathe in goes through the trachea which splits into two tubes called bronchi, one going to each lung.
• The bronchi split into progressively smaller tubes called bronchioles which finally at the alveoli.
• Oxygen diffuses out of the alveoli in to the blood and carbon dioxide diffuses out of the blood into the alveoli.
• The alveoli are surrounded by blood capillaries so that there is a shorter diffusion path
• Humans have a double circulatory system- two circuits joined together.
• The heart is a pumping organ that keeps the blood flowing around the body. Its walls are mainly made of muscle tissue.
• The heart has valves so that blood always flows in the right direction- prevents it flowing backwards.
• Arteries called coronary arteries branch off the aorta and surround the heart, allowing to get oxygenated blood.
• The body's natural pacemaker is a group of cells in the right atrium wall that produce a small electric impulses that is transmitted to surrounding muscle cells causing them to contract.
• An artificial pacemaker is often used to control heartbeat if your natural pacemaker cannot. It is a small device implanted under the skin that has a wire going to the heart, producing an electric current that keeps a regular heartbeat.
• Arteries- carry blood away from the heart
• Capillaries- these are involved in the exchange of materials at the tissues