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Movement State that the skeleton provides a framework for skeleton and muscle attachment State that the skeleton protects the heart, lungs, brain and spinal cord The spine protects the spinal cord. The skull protects the brain. The rib cage protects the lungs. 1 Describe the range of movements allowed by a ball and socket joint and by a hinge joint Where bones of the skeleton meet, joints are formed. Joints allow the skeleton to bend and move in different ways. There are 2 kinds of joint, ball and socket joints and hinge joints. Ball and socket Type of joint Ball and socket Hinge Hinge joint Examples Hip, shoulder Elbow, knee Type of movement move in all three dimensions In one plane only State the functions of ligaments and cartilage at a joint At a joint, the bones are held together by ligaments. 2 Cartilage is found at the ends of the bones and acts as a shock absorber and allows smooth movement. Describe the structure of a synovial joint and state the functions of its parts Part of the joint Function Ligament Holds bones together Synovial membrane Secretes synovial fluid Synovial fluid Lubricates the joint Cartilage Acts as a shock absorber State that bone is formed by living cells These cells are supplied with food and oxygen by blood vessels. That is why if you break a bone it will bleed. State that bone is composed of flexible fibres and hard minerals Roasting removes the flexibility of bone. The acid removes the hardness from the bone and it now bends easily. State that muscles are attached to bones by tendons 3 Explain why tendons are inelastic Tendons are inelastic i.e. they do not stretch very much so that the movement of the muscle will be passed on to the bone. Describe how movement is brought about by muscle contraction When a muscle contracts (gets shorter), the tendons pull on the bones and the arm moves. Explain the need for a pair of opposing muscles at a joint Muscles can only contract and relax. Therefore most muscles work against each other in pairs. If one muscle straightens the arm, the other muscle bends it. The tricep contracts The bicep relaxes The arm straightens The bicep contracts The tricep relaxes The arm bends 4 The Need for Energy State the effects of the imbalance between energy input and output The amount of energy needed by a person will vary according to their age, gender, job and lifestyle. We get our energy from our food. If you take in more energy in food than you use, your body will store fat. If you take in less energy in food than you require, your body will lose fat. State that oxygen is absorbed and carbon dioxide released in breathing You need oxygen to release the energy from your food. In doing this a waste gas, carbon dioxide, is produced. You obtain oxygen and get rid of carbon dioxide by breathing. Your lungs are the organs that allow you to do this. Describe the internal structures of the lungs Air passes in to the body through the mouth and nose. It then passes down the trachea. The trachea branches into 2 bronchi which divide into smaller tubes called bronchioles. Each bronchiole ends in an air sac or alveoli. 5 The lungs have a very large surface area. They feel spongy and will float in water because they have air in them. They are pinky red in colour because they have a good blood supply. Describe the mechanism of breathing in humans Movements of the chest wall help us to inhale (take in air) and exhale (give out air). The diaphragm and the intercostal muscles between the ribs are used to help us breathe. To breathe in: o The muscles of the diaphragm contract causing the diaphragm to move down o The intercostal muscles between the ribs contract causing the ribs to move up and out o The volume of the chest increases and the pressure in the lungs decreases o Air is drawn in. To breathe out: o The muscles of the diaphragm relax causing the diaphragm to move up o The intercostal muscles between the ribs relax causing the ribs to move down and in o The volume of the chest decreases and the pressure in the lungs increases o Air is forced out. 6 Describe gas exchange between the air sacs and the surrounding blood vessels The bronchi divide into smaller and smaller tubes called bronchioles. Each bronchiole ends in an air sac which is lined in moisture. Oxygen dissolves in this moisture and diffuses from the lungs into the blood because there is a higher concentration in the air sac than in the blood. Carbon dioxide diffuses in the opposite direction because there is a higher concentration in the blood than in the air sac. Describe the features which make lungs efficient gas exchange structures 1 The air sacs are thin to let gases through easily. 2 The air sacs have many blood capillaries in close contact with them. 3 Because there are so many air sacs, they make a large surface area. 4 The air sacs are lined with mucus which is moist so that gases can dissolve. Explain the function of cilia, cartilage and mucus in the trachea and bronchi Mucus secreting cell Air contains dust and germs which could damage your lungs. The air you breathe is cleaned by cells lining the air tubes. These cells have small hairs or cilia which move in waves up to the mouth. A slippery liquid called mucus is made by the cells and this traps dirt. The mucus acts like a conveyor belt which is moved by the beating cilia. In this way dirt and germs are moved up to the mouth where they are swallowed. 7 Cartilage rings are found around the trachea and bronchi to prevent them from closing. Identify the four chambers of the heart Oxygen and food are carried to all the body’s cells by the blood. Blood is pumped around the body by the heart The heart is made of muscle. There are four chambers in the heart. Right atrium Left atrium Right ventricle Left ventricle Describe the path of blood flow through the heart and its associated blood vessels 8 Deoxygenated blood i.e. low in oxygen returns to the heart via the vena cava after travelling to all parts of the body. It enters the heart at the right atrium. The right atrium then pumps blood out through the pulmonary artery to the lungs. In the lungs the blood picks up oxygen and loses carbon dioxide. The oxygenated blood then returns to the heart via the pulmonary vein entering the left atrium. The left ventricle pumps blood out through the aorta to the body. Describe the positions and functions of the heart valves Heart valves stop blood flowing in the wrong direction and allow blood to flow in one direction only. Valves are found between the atria and the ventricles and also as the blood leaves the heart, in the aorta and the pulmonary artery. Explain the difference in thickness of the walls of the ventricles 9 The ventricles have thicker walls than the atria. The left ventricle has a thicker wall than the right ventricle because the left ventricle has to pump blood right round the body and the right ventricle only has to pump blood to the lungs. State that the heart obtains its blood supply from coronary arteries The coronary arteries supply food and oxygen to the heart muscle. When these blood vessels get blocked, you can suffer a heart attack. State that blood leaves the heart in arteries, flows through capillaries and returns to the heart in veins Blood is carried away from the heart in arteries. These arteries carry blood to the body’s organs and tissues. In the organs the arteries split up into a network of tiny tubes called capillaries. Substances are exchanged between the capillaries and the tissues. Blood leaves the tissues in vessels called veins which carry the blood back to the heart. Describe gas exchange between the body cells and the surrounding capillaries 10 Carbon dioxide oxygen Oxygen diffuses from the high concentration in the capillary blood across into the body cells. Carbon dioxide diffuses from the high concentration in the cells into the plasma. Describe the features of a capillary network which allow efficient gas exchange The capillary network allows efficient exchange of gas, food and waste because 1 they are narrow and thin walled which gives a greater surface area to allow fast diffusion of gases etc. 2 they are very long which also increases the surface area. 3 no cell is ever far away from a capillary thus ensuring easy exchange. State that the pulse indicates that blood is flowing through an artery The heartbeat can be felt as a pulse in arteries which lie just underneath the 11 skin. Pulse can be detected at different parts of the body Describe the function of red blood cells and plasma in the transport of respiratory gases and food Blood is made up of cells floating in a liquid called plasma. The plasma also carries dissolved substances such as carbon dioxide, digested food and waste products. Red blood cells carry oxygen. Explain the function of haemoglobin in the transport of oxygen 12 A red pigment called haemoglobin is found in red blood cells. Its function is to combine with oxygen to form oxyhaemoglobin. At the lungs, haemoglobin combines with oxygen to make oxyhaemoglobin. At the tissues, oxyhaemoglobin releases oxygen and becomes haemoglobin again. at lungs haemoglobin + oxygen oxyhaemoglobin at tissues Co-ordination 13 State that judgement of distance is more accurate using two eyes rather than one As well as detecting pictures, your eye also allows you to judge distances. Having two eyes rather than one makes judgement of distance more accurate. Explain the relationship between judgement of distance and binocular vision Your eyes are set in the front of your head. This gives you binocular vision which allows you to see things in three dimensions. Each eye sees the object slightly differently. The two messages are sent to the brain which puts the two pictures together to form a 3-dimensional image. Identify the cornea, iris, lens, retina, optic nerve and state their function The eye is the sense organ that you use to detect light. Part of the eye Cornea Lens Iris Retina Optic nerve Function Tough, transparent to let light in and begins to bring it to a focus Focuses light onto the retina Coloured part, muscles control the size of the pupil thereby controlling how much light enters the eye Light is converted to nerve impulses Carries nerve impulses from the retina to the brain State that the judgement of direction of sound is more accurate using two ears rather than one 14 Your ears, as well as detecting sound, can also help you judge the direction from which the sound is coming. Two ears are better than one at detecting the direction of sound. The sound arrives from each ear at slightly different times, thus giving an indication from where the sound is coming. Identify the ear drum, middle ear bones, cochlea, auditory nerve and semi-circular canals and state their functions The ear is the sense organ you use to detect sound. Part of the ear Function Eardrum Thin membrane set vibrating by sound waves which it passes on to middle ear bones Middle ear Amplify and transmit sound vibrations to bones the cochlea Cochlea Liquid filled tube. Converts sound vibrations into nerve impulses Auditory nerve Carries nerve impulses from the cochlea to the brain Semi circular Contain liquid which moves in response to canals movements of the head Explain how the arrangement of semi-circular canals is related to their function Your semi-circular canals help you to balance. The three semi-circular canals are three fluid-filled tubes arranged at right angles to each other. This is so that when the head moves, fluid in one or more of the canals will move. Since the canals are at right angles to each other the brain can tell us which way up we are and use the information to control your balance. State that the nervous system is composed of the brain, spinal cord and nerves The nervous system is composed of the brain, the spinal cord and nerves. 15 State that the nerves carry information from the senses to the central nervous system and from the central nervous system to the muscles The brain sorts out information. The spinal cord sends information to and from the brain. The brain and spinal cord make up the central nervous system (CNS). Describe how a reflex action works, using a simple model of a reflex arc A reflex action is a rapid, automatic response to a stimulus. It is an involuntary action which does not always involve the brain. Reflex actions happen so quickly that there is often no time for the nerve impulses to reach the brain. Often the impulse only goes to the spinal cord and the brain becomes aware of the action only after it has happened. 16 The reflex arc is an arrangement of nerve cells which make sure that you react quickly to hazardous stimuli e.g. picking up something hot. Sensory nerve cells send a message to the spinal cord. A relay nerve or interneurone connects the sensory nerve to the motor nerve in the spinal cord. A signal to make a muscle contract is then sent down a motor nerve. State that the central nervous system sorts out information from the senses and sends messages to those muscles which make the appropriate response Nerves carry information from the senses to the CNS. The CNS sorts out the information and sends information to muscles to make the appropriate response. Nerves carry information from the CNS to the muscles. Information received from the sensory nerves is sorted out by the CNS. Information from the CNS is then carried by the motor nerves to the appropriate muscles which then contract. 17 Identify the cerebrum, cerebellum and the medulla and state their functions in simple terms The brain is the control centre of the nervous system. The brain is made up of three main parts; the cerebrum, the cerebellum and the medulla. cerebrum The cerebrum is responsible for memory, thought and intelligence. The cerebellum controls balance and muscular co-ordination. The medulla controls unconscious activities such as breathing and heart rate. Changing Levels of Performance State that continuous or rapidly repeated contraction of muscle results in fatigue If you exercise very hard or for a long time, eventually your muscles will ache. This is called muscle fatigue. The muscles will stop working. State that muscle fatigue results from a lack of oxygen and a build up of lactic acid Muscle fatigue occurs when muscles do not receive enough oxygen and because a waste product, lactic acid, has built up in the muscles. Explain muscle fatigue in terms of anaerobic respiration If not enough oxygen is available for your muscles to carry out aerobic respiration, they are able to switch to anaerobic respiration to allow you to carry on using the muscles for a while longer. Instead of producing carbon dioxide and water as in aerobic respiration, your muscles produce lactic acid. This build up of lactic acid makes your muscles fatigue. With oxygen glucose + oxygen carbon dioxide + water Without oxygen glucose lactic acid 18 Explain why pulse rate and breathing rate increase with exercise After exercise the breathing rate has increased. This is so that more oxygen can be absorbed into the lungs and blood stream. After exercise the pulse rate has increased. This is so that more food and oxygen can be carried to the muscles. State that with exercise the pulse rate, breathing rate and lactic acid level rise less in an athlete than in an untrained person State that recovery time is the time taken to return to normal levels of pulse rate, breathing rate and lactic acid The graph shows the heart rate before, during and after a period of exercise. State that training improves the efficiency of the lungs and circulation Training allows a person to exercise more vigorously and for a much longer time before muscle fatigue sets in. Training improves your body’s efficiency in several ways: Your heart is able to pump more blood every beat The flow of blood through the muscles increases Your lung volume is increased which means that each breath carries more oxygen All of these provide food and oxygen to the muscles much quicker so your pulse rate can stay lower Since more oxygen reaches the muscles, less lactic acid is made. 19 Describe how recovery time can be used as an indication of physical fitness In general, the longer your recovery time the less fit you may be. A group of pupils measured their resting pulse rates. They then exercised for 3 minutes and measured their pulse rates 2 minutes, 10 minutes and 20 minutes after exercise. They recorded their results in the table below. Condition Resting 2 minutes after exercise 10 minutes after exercise 20 minutes after exercise Pulse Rate (beats/min) Jane Brenda 82 65 120 130 Wilma 77 120 100 70 95 90 65 85 Brenda is the fittest as she took the shortest time to recover. Explain the relationship between the effects of training and recovery time If you are fit, you make less lactic acid so there is less to get rid of. Efficient heart and lungs provide oxygen much more quickly. All of this means that training reduces recovery time. 20