IES LAS MARINAS SECCIÓN BILINGÜE PHYSICAL EDUCATION AND SPORT 2Ä ESO UNIT I THE HUMAN BODY AND PHYSICAL ACTIVITY MICHAEL PHELPS The human body The human body is the most wonderful, complex machine in the world. Your body can walk and run, climb and sit. It can see, hear, smell, taste, and feel. It can eat, talk, laugh, lift things, play games, think, and read. While these things are going on, you are breathing; there is blood flowing through your blood vessels; you are digesting food; and your body is doing a million other jobs at the same time! All through your life this marvellous machine is at work-even when you are sleeping. These are a few systems of the human body: 1 The nervous system: Your brain, your spinal cord, and the millions of nerve cells in your body make up your nervous system. 2 The circulatory system: Your circulatory system consists of your heart, arteries, veins, and very thin blood vessels called capillaries. 3 The respiratory system: Oxygen enters your body through your nose or mouth, moves down your windpipe and into your lungs. Your lungs are the most important part of your respiratory system. 4 The muscular and skeletal systems which allow us to move. 5 The digestive system: Your mouth, oesophagus, stomach, large and small intestines and other organs make up your digestive system. 1
IES LAS MARINAS SECCIÓN BILINGÜE 1 The Nervous System The nervous system controls everything you do, including breathing, walking, thinking, and feeling. This system consists of your brain, spinal cord, and all the nerves of your body. The brain is the control centre and the spinal cord is the major highway to and from the brain. The nerves carry the messages to and from the body, so the brain can interpret them and take action. The two main kinds of nerves are sensory nerves and motor nerves. 1. Sensory nerves carry signals from the sense organs to the brain or spinal cord. The eyes, ears, nose, mouth and skin are sense organs. 2. Motor nerves carry messages from the brain and spinal cord to various parts of the body. Every movement we make and every thought we have involves the nervous system in some way. The control centre of the human body is the human brain. 2
IES LAS MARINAS SECCIÓN BILINGÜE 2 Circulatory System The circulatory system consists of the heart and blood vessels. The heart acts as a pump to keep blood moving throughout the body. Arteries are blood vessels which carry blood away from the heart. This blood contains a lot of oxygen and nutrients for the body. Veins are blood vessels which carry blood to the heart from various parts of the body. This blood is low in oxygen and nutrients. Red Blood Cells: Cellular Transport System Red blood cells function by carrying oxygen to every part of the body, and then carrying carbon dioxide back to the lungs. Red blood cells are very well designed to perform this important job. First, they are full of haemoglobin, which transports oxygen to other cells. Interestingly, red blood cells have no nuclei, a feature which makes even more room for haemoglobin. Red blood cells are the only cells in the body that do not have a nucleus. Second, they are shaped like disks. This shape greatly increases their surface area. The large surface area is important because it improves the efficiency of oxygen transfer between haemoglobin and the tissues where the oxygen is needed. Blood Circulation: A Continuous Loop One of the landmarks in medical history was William Harvey's discovery that blood flows through the body in a continuous, closed loop. The Heart: A Pump That Never Stops The heart is a powerful pump that beats continuously during life to circulate the blood throughout the body. The heart has four separate chambers. The human circulatory system. Red indicates oxygenated blood, blue 3
IES LAS MARINAS SECCIÓN BILINGÜE indicates deoxygenated 3 Respiratory System Respiration is the process by which our bodies take in and use oxygen. The respiratory system allows us to breathe. It also supplies oxygen to the blood and removes carbon dioxide from our bodies. When we breathe in, our lungs take in oxygen. When we breathe out, our lungs remove carbon dioxide and water from our bodies. The nose, mouth, windpipe (trachea), lungs and diaphragm are all parts of the respiratory system. The diaphragm is a large muscle which controls our breathing. When the diaphragm moves down, air is pulled into the lungs. When the diaphragm moves up, air is pushed out of the lungs. Respiratory Tree: From the Windpipe to the Cells The structure of the lungs is like the branches of a tree. Starting with the trachea (windpipe), the respiratory tree branches initially to form two main bronchi (airways) that enter the right and left lungs. The main bronchi then branch again and again, first forming smaller bronchi and then even smaller bronchioles. At the end of the smallest bronchioles, there are tiny air sacs called "alveoli." It is in the alveoli that oxygen comes into contact with the red blood cells that will carry it to all parts of the body. 4
IES LAS MARINAS SECCIÓN BILINGÜE http://projects.edtech.sandi.net/brooklyn/humanbody/ Webquest on the human body (very good) 4 The Muscular and Skeletal Systems The muscles are the active part of the apparatus of locomotion. Their task is to move the body. The muscles comprise 40% of the body's weight. The body has 300 individual muscles in different shapes and sizes. The skeletal system consists of 206 bones as well as joints, cartilage and ligaments; the skeletal system provides the strong, internal framework that supports our body. 5
THE HUMAN MUSCULAR SYSTEM The Benefits of Exercise Everyone can benefit from regular exercise. Young people who are active will: have stronger muscles and bones have a leaner body because exercise helps control body fat be less likely to become overweight decrease the risk of developing type 2 diabetes possibly lower blood pressure and blood cholesterol levels have a more positive attitude to life have better personal values in life (self-control, responsibility, solidarity, healthy competitiveness, social integration, etc. In addition to the health benefits of regular exercise, young people who are physically fit sleep better and can better handle the physical and emotional challenges that a typical day presents from simple things like running to catch a bus or bending down to tie a shoe, to more challenging things like studying for a test or competing in a sports competition. 6
IES LAS MARINAS SECCIÓN BILINGÜE EXTRA READING The Immediate Effects of Exercise on the Body When we exercise, especially cardiovascular exercise, there are several immediate effects on our bodies. These are as follows: 1. YOUR HEART BEATS FASTER AND STRONGER The rise in pulse rate allows more blood to be pumped to the lungs faster so that more oxygen can be circulated to the working muscles. 2. YOUR BREATHING QUICKENS AND DEEPENS An increase in breathing rate helps us to get more oxygen to the working muscles, but eventually if we work hard enough for long enough we will reach a point where we cannot get enough oxygen (oxygen debt) and our muscles will stop working. The more efficient the body is at getting oxygen into the blood and to the muscles, the longer we can exercise for. 3. YOUR BODY TEMPERATURE WILL RISE When we exercise our muscles produce heat so our body temperature rises (normal body temperature is about 37ºC). We can control our body temperature by sweating when we are too hot and shivering when we are too cold. 4. YOU START TO SWEAT Most energy produced through respiration is used by the muscles, but some of it changes into heat and so we begin to sweat. Sweat on the skin will evaporate, but to do this requires energy. It gets this from the body as heat and as it uses this heat our body temperature falls (experiment by licking the back of your hand and blowing on it). The two problems that are caused by sweating too much is that we can become dehydrated and lose salt. The loss of salt can cause cramps. 7
5. YOUR MUSCLES BEGIN TO ACHE We have seen that glucose combined with oxygen produce energy, carbon dioxide and water. But as we exercise harder there is a limit to how much oxygen we can get to the muscles. When we cannot get enough oxygen to the muscles this is know as oxygen debt and so a different way of getting energy is used and this produces lactic acid. A build up of lactic acid causes the muscle to ache and eventually it will cause cramp and the muscles will stop working. The body can get rid of this lactic acid by resting until the blood can bring enough oxygen to the muscles to pay-off the oxygen debt. Oxygen will break down the lactic acid into water and carbon dioxide. USAIN BOLT WORLD RECORD SPRINTER 8
ACTIVITIES 1 Name five systems of the human body: a... b... c... d... e... Remember the systems: Numerous Clowns Remember Many Silly Dances 2 Fill in this diagram: N S B S c N s 9
3 Fill in the missing information: The b.. is the c. c. of the human body The s. c. is the m.. h. to and from the b 4 Name two kinds of nerves: a. S.. n.s b. M. n.s What do s. n s do? They 10
Name five sense organs: 1./2.../3.. 4. /5 What do m n..s do? They 5 Rásumá: The Nervous System The nervous system controls everything you do. This system consists of your,, and all the of your body. The is the c c and the s c is the m h to and from the. The nerves carry m s to and from the body, so the brain can interpret them and take action. 6 What does the circulatory system consist of?... 7 Fill in the missing words: The h is like a p.. 11
A are b. v. that carry b. away from the h / This b.. contains a lot of o.. and n.. V are b v that carry b. t the h / This b is l.. in o and n 8 Look at the following diagram and answer the questions: 1. What is this system called? 2. What are the lines in red called? 3. What do these red lines contain? 4. What are the blue lines called? 5. What is the function of red blood cells? a). b). 6. Who discovered the nature of the circulatory system?. 7. Blood flows through the body in a continuous l.. 9 Write a summary of the circulatory system: 12
10 Fill in the missing information: The r. s.. n.. m.. w. l. d.. 11 What is respiration? 12 What is the diaphragm?.. 13 What does the diaphragm do?. 13
IES LAS MARINAS SECCIÓN BILINGÜE 14 Label the diagrams X X 14
15 Lung Capacity: an Experiment Here is a way to find out how much air your lungs can hold. Fill a large glass bottle or plastic container with water. Half fill a sink or large basin with water. Put the container of water in the sink. Put your hand over the top of the container and turn it over. Put a plastic tube into the opening in the container, with one end of the tube well above the water in the sink. Hold the container in place upside down. Take a deep breath. Blow into the tube. The air from your lungs will push water out of the jug. The amount of air in the container after you have exhaled as much as you can is the amount of air your lungs can hold. This is also called your lung capacity. 16 The muscles are the active part of the a. of l. 17 What percentage of the body s weight are the muscles?... 18 How many individual muscles are there in the body?. 19 How many bones are there in the skeletal system? 20 Watch the film Chariots of Fire (1981). It is a British film based on the true story of British athletes preparing for and competing in the 1924 Summer Olympics. What do you think the film tells us about the benefits of physical exercise and sport? 15