Functional Anatomy PDF - BTEC Nationals Sport & Exercise Science

Functional Anatomy 2 Copyright © 2013. Pearson Education Limited. Al...

Functional Anatomy 2 Copyright © 2013. Pearson Education Limited. All rights reserved. Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  UNIT 2 Getting to know your unit To understand what happens during sport and exercise, you must know Assessm ent about the different body systems. This unit examines the systems that This unit is assesse d by make up the body, how these systems interact and work with each an examin ation that other, and why they are so important to sports performance. You will be is set and marke d by introduced to the structures and functions of the four key systems and the effects that sport and exercise has on them, and how these systems Pearson. work together effectively to produce movement. How you will be assessed This unit will be assessed by an examination set by Pearson. It will last 1 hour and 30 minutes and contain a number of short and long answer style questions. There will be a total of 80 marks available in the examination. During this examination you will need to show your knowledge and understanding of the anatomy of the cardiovascular, respiratory, skeletal and muscular systems and how they work together to produce movement. Throughout the unit, you will find assessment practice activities to help you prepare for the exam. Completing each of these will give you an insight into the types of questions and, more importantly, how to answer them. Unit 2 has four assessment outcomes (AO) which will be included in the external examination. Certain ‘command words’ are associated with each assessment outcome – see Table 2.1. ▸▸ AO1 Demonstrate knowledge and understanding of the language, structure, characteristics and function of each anatomical system Command words: describe, give, identify, name, state Marks: range from 1 to 5 marks ▸▸ AO2 Apply knowledge and understanding of the structure, characteristics and function of the anatomical systems in context Command words: describe, explain Marks: range from 2 to 5 marks Copyright © 2013. Pearson Education Limited. All rights reserved. ▸▸ AO3 Analyse the anatomical systems’ effectiveness in producing sport and exercise movements and evaluate their impact on performing movements successfully Command words: analyse, assess, evaluate, discuss, to what extent Marks: range from 8 to 20 marks ▸▸ AO4 Make connections between anatomical systems and how they interrelate in order to carry out different exercises and sporting movements in context Command words: analyse, assess, evaluate, discuss, to what extent Marks: range from 8 to 20 marks 40 Functional Anatomy Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Getting to know your unit UNIT 2 ▸▸ Table 2.1: Command words used in this unit Functional Anatomy Command word Definition – what it is asking you to do Analyse Identify several relevant facts of a topic, demonstrate how they are linked and then explain the importance of each, often in relation to the other facts. Assess Carefully consider varied factors or events that apply to a specific situation and identify those which are the most important or relevant to arrive at a conclusion. Describe Give a full account of all the information, including all the relevant details of any features, of a topic. Discuss Identify an issue/situation/problem/argument that is being assessed and explore all aspects and investigate fully. Evaluate Bring all the relevant information on a topic together and make a judgement on it (for example, on its success, importance, strengths, weaknesses, alternative actions, relevant data or information). This should be clearly supported by the information you have gathered. Explain Make an idea, situation or problem clear to your reader by making a point/statement or by linking the point/statement with a justification/ expansion. Give Provide examples, justifications and/or reasons to a context. Identify State the key fact(s) about a topic or subject. The word ‘outline’ is similar. You should assess factual information that may require a single-word answer, although sometimes a few words or a maximum of a single sentence are required. State/name Give a definition or example. To what extent Review information then bring it together to form a judgement or conclusion, after giving a balanced and reasoned argument. Copyright © 2013. Pearson Education Limited. All rights reserved. 41 Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Getting started The human body is made up of a number of different systems that interact together, allowing you to take part in sport and exercise. Write a list of how the body changes immediately before, during and after a sport or exercise session. Consider these changes and think about the system that is affected. Why do you think these changes occur? A Anatomical positions, terms and references When examining the human body it is important you are able to refer to the location of different parts of the body. This is particularly important when describing movements and body locations in relation to each other. The ‘anatomical position’ is a standard standing position used in most diagrams of the body (see Figure 2.1), with the body facing forward, feet pointed forward and slightly apart, and arms hanging down on each side. This is also known as the point of reference. A number of specialist terms that you need to understand are described in Table 2.2. ▸▸ Table 2.2: Anatomical terms Superior Anatomical term Definition Anterior To the front or in front Posterior Posterior To the rear or behind Anterior Lateral Away from the midline or axis, an Proximal end of arm imaginary line down the centre of the body Medial Towards the midline or axis Midline of body Proximal Near to the root or origin (e.g. the proximal of the arm is towards the Medial shoulder) Lateral Distal Away from the root or origin (e.g. the distal of the arm is towards the hand) Distal end of arm Superior Above Copyright © 2013. Pearson Education Limited. All rights reserved. Inferior Below Peripheral Away from the centre of the body Superficial Near the surface of the skin Deep Away from the surface of the skin Supine Lying down with face pointing upwards Prone Lying down with face pointing downwards Inferior ▸▸ Figure 2.1: Anatomical positions 42 Functional Anatomy Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Learning aim B UNIT 2 Functional Anatomy B Anatomy of the cardiovascular system The cardiovascular system is also known as the circulatory system. It is the major transport system in your body, carrying food, oxygen and all other essential products to cells, and taking away waste products of respiration and other cellular processes, such as carbon dioxide. Anatomy of the heart The heart is a unique hollow muscle and is the pump of the cardiovascular system. It is located under the sternum (a long flat bone like a neck tie at the front of the ribcage, which provides protection) and is about the size of a closed fist. The heart drives blood into and through the arteries to the tissues and working muscles. It is surrounded by a twin-layered sac known as the pericardium. The cavity between the layers is filled with pericardial fluid, which prevents friction as the heart beats. The heart wall is made up of three layers: the epicardium (the outer layer), the myocardium (the strong middle layer that forms most of the heart wall) and the endocardium (the inner layer). The heart is actually two pumps in one: the two chambers on the right (the right atrium and the right ventricle) and the two chambers on the left (the left atrium and the left ventricle). The right side is separated from the left by a solid wall known as the septum. This prevents the blood on the right side coming into contact with the blood on the left side. The specific parts of the heart, also shown in Figure 2.2, are as follows. Key terms ▸▸ Coronary arteries – the blood vessels supplying oxygenated blood to the heart Anatomy – study of the muscle. There are two coronary arteries, the left and right. structure of the body such ▸▸ Atria – the upper chambers of the heart. They receive blood returning to your as the skeletal, muscular or heart from either the body or the lungs. The right atrium receives deoxygenated cardiovascular systems. blood via the superior and inferior vena cava (a large vein). The left atrium receives Oxygenated blood – blood oxygenated blood from the left and right pulmonary veins. containing oxygen. ▸▸ Ventricles – the pumping chambers of the heart. They have thicker walls than Deoxygenated blood the atria. The right ventricle pumps blood to the pulmonary circulation for the – blood without oxygen lungs and the left ventricle pumps blood to the systemic circulation for the body (containing carbon dioxide). including the muscles. ▸▸ Bicuspid (mitral) valve – one of the four valves in the heart, situated between the left atrium and the left ventricle. It allows the blood to flow in one direction only, Copyright © 2013. Pearson Education Limited. All rights reserved. from the left atrium to the left ventricle. ▸▸ Tricuspid valve – located between the right atrium and the right ventricle, it allows blood to flow from the right atrium to the right ventricle and prevents blood from flowing backwards. ▸▸ Semilunar valves (aortic valve and pulmonary valve) – between the left ventricle and the aorta, these prevent backflow from the aorta into the left ventricle. They are also situated between the right ventricle and the pulmonary artery. ▸▸ Chordae tendineae – chord-like tendons connected to the bicuspid and tricuspid valves to prevent valves turning inside out. 43 Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Key = oxygenated blood = deoxygenated blood Superior Aorta vena cava Left Right pulmonary pulmonary artery artery Left pulmonary veins Right pulmonary Left atrium veins Bicuspid (mitral) valve Right Left ventricle atrium Myocardium Pulmonary (heart muscle) (semilunar) valve Aortic (semilunar) valve Tricuspid Septum valve Right Epicardium Inferior Endocardium ventricle Chordae (inner surface (outer surface vena cava of myocardium) tendineae of myocardium) ▸▸ Figure 2.2: Diagram of the heart Function of the heart Lungs The chambers on the right of the heart supply blood at a low pressure to the lungs via blood vessels, where gaseous Pulmonary Pulmonary artery Pulmonary vein exchange (see pages 51–52) takes place: oxygen that has circulation been breathed in through the lungs is transferred to the Right side Left side blood, and carbon dioxide, a waste product from the of heart of heart body’s activities, is deposited ready to be exhaled from Copyright © 2013. Pearson Education Limited. All rights reserved. the body. This blood is then returned to the left side of the Aorta heart via the blood vessels (see the next section for more Vena cava information about blood vessels). Systemic circulation When the chambers of the left side of the heart are full, it contracts at the same time as the right side. This side of the heart supplies oxygenated blood via the blood vessels to the tissues of the body such as muscle cells. Oxygen passes from the blood to the cells, and carbon dioxide (a waste product of aerobic respiration) passes into the blood from the cells. The blood then returns to the right atrium of the All body tissues heart via the blood vessels. (non–lung tissues) Circulation through the heart is shown in Figure 2.3. ▸▸ Figure 2.3: Double circulation through the heart 44 Functional Anatomy Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Learning aim B UNIT 2 Functional Anatomy P aus e point Describe the structure and function of the heart. Hint Draw a basic diagram of the heart and label each part ensuring you check your spelling of anatomical terms. Extend Label the blood flow and consider the double circulation through the heart. Blood vessels ▸▸ Table 2.3: – continued Arterioles Have thinner walls than arteries and control As the heart contracts, blood flows around the body in blood distribution by changing diameter. a complex network of vessels. There are five main blood This adjusts blood flow to the capillaries in vessels in the human body. response to differing demands for oxygen. ▸▸ Aorta – this is the body’s main artery. It originates in the For example, during exercise, muscles require left ventricle and carries oxygenated blood to all parts increased blood flow for extra oxygen and the diameter of the arterioles leading to muscles of the body except the lungs. dilates. To compensate for this increase in ▸▸ Superior vena cava – a vein that receives blood demand, other areas of the body (e.g. deoxygenated blood from the upper body to empty the gut) have their blood flow temporarily into the right atrium of the heart. reduced, and the diameter of their arterioles is decreased. ▸▸ Inferior vena cava – a vein that receives deoxygenated blood from the lower body to empty into the right Veins Allow venous return (the return of deoxygenated blood to the heart). atrium of the heart. Have thinner walls than arteries and a ▸▸ Pulmonary vein – carries oxygenated blood from the relatively large diameter. lungs to the left atrium of the heart. When blood reaches veins it is flowing slowly ▸▸ Pulmonary artery – carries deoxygenated blood from and under low pressure. Contracting muscles the heart back to the lungs. It is the only artery that push the thin walls of the veins inwards to squeeze blood towards the heart. As muscle carries deoxygenated blood. contractions are intermittent, a number of pocket valves in veins prevent any backflow Structure of blood vessels when muscles relax. The structure of different blood vessels depends on their Mainly close to the surface and can be seen function and the pressure of blood within them – see under the skin. Table 2.3. They branch into venules, connected to the capillary network. ▸▸ Table 2.3: Types of blood vessel Venules Small vessels that connect capillaries to veins. Blood Anatomy and location Take blood from the capillaries and transport vessel this deoxygenated blood under low pressure to the veins which, in turn, lead back to the Arteries Carry blood away from the heart and (apart heart. from the pulmonary artery) carry oxygenated blood. Capillaries Connect arteries and veins by uniting Copyright © 2013. Pearson Education Limited. All rights reserved. arterioles and venules. Thick muscular walls carry blood at high speeds under high pressure. As they have Smallest of all blood vessels, narrow and thin. high pressure, they do not need valves, except Allow the diffusion of oxygen and nutrients where the pulmonary artery leaves the heart. required by the body’s cells – their walls are Have two major properties: elasticity one cell thick, allowing nutrients, oxygen and and contractility – the smooth muscle waste products to pass through. surrounding them enables their diameter to The number in a muscle may increase after decrease and increase as needed (e.g. when frequent and appropriate exercise. This means the heart ejects blood into the large arteries, the surrounding muscles get the oxygen and they expand). This contractility helps maintain nutrients to produce energy. blood pressure as blood flow changes. Pressure of blood is higher than veins, but less Largely deep, except where they can be felt than arteries. at a pulse point. They branch into smaller arterioles that deliver blood to the capillaries. 45 Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Lumen The walls of blood vessels have three layers – see Figure Vein 2.4a and b. These surround the lumen, which is the blood- Fibrous tissue containing vessel. ▸▸ The inner tunica intima lines the lumen and creates a slick surface, minimising friction as the blood passes. Oval ▸▸ The middle tunica media layer is made from smooth lumen muscle cells and elastic tissue. Depending on the needs Lining of the body, either vasodilation or vasoconstriction occurs. ▸▸ The outer tunica externa layer is made from collagen Inner layer fibres that protect and reinforce the vessel, and keep it (endothelium) in place in the body’s structure. Middle layer (smooth muscle Key terms and elastic tissue) Vasodilation – an increase in the diameter of blood vessels. Outer layer (elastic and Vasoconstriction – a reduction in the diameter of collagenous blood vessels. tissue) Lumen Collagen – a protein-based building material used in the repair of tissues. Collagen also provides strength ▸▸ Figure 2.4b: Structure of a vein and cushioning for body parts. Composition of blood The average adult has approximately 4–5 litres of blood. Artery Blood is composed of: Elastic fibres ▸▸ red blood cells (erythrocytes) – carry oxygen to all living tissue. They contain a protein called haemoglobin, giving blood its red colour, which when combined with oxygen forms oxyhaemoglobin. They are round, flattened discs Round with an indented shape giving them a large surface area lumen and allowing them to flow easily within plasma. A drop of blood contains millions of red blood cells Muscle ▸▸ plasma – the straw-coloured liquid in which all Lining layer blood cells are suspended. It is approximately 90 per Muscle layer cent water and contains electrolytes such as sodium, Tunica potassium and proteins. It also carries carbon dioxide, intima dissolved as carbonic acid Tunica ▸▸ white blood cells (leucocytes) – the components of Tunica externa blood that protect the body from infections, they account Copyright © 2013. Pearson Education Limited. All rights reserved. media for less than 1 per cent of blood volume. They identify, destroy and remove from the body pathogens such as bacteria or viruses. They originate in bone marrow ▸▸ platelets (thrombocytes) – disc-shaped cell fragments Lumen produced in the bone marrow. Their primary function is ▸▸ Figure 2.4a: Structure of an artery clotting to prevent blood loss, sticking to the damaged Vein area to form a temporary plug to seal the break. Fibrous tissue P aus e point Explain the functions of veins, venules, arteries, arterioles and capillaries. Hint What are the main differences between the types of blood vessel? Oval Extend lumen Explain why there are structural differences between arteries and veins. Lining 46 Functional Anatomy Inner layer (endothelium) Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47. Middle layer  Learning aim B UNIT 2 temperature as heat loss reduces as blood is moved Functional Anatomy Discussion away from the surface. In groups, discuss the role and importance of the ▸▸ Blood provides the fluid environment for cells and cardiovascular system in sport and exercise. Consider is the medium which carries material to and from each component of the system. You could also these cells. White blood cells (leucocytes) are essential consider the short-term responses of exercise to these to fight infection and defend against viruses and components as well as the long-term adaptations. bacteria. Leucocytes are constantly produced inside bone marrow and are stored in your blood. They can consume and ingest pathogens, produce antibodies Lymphatic system that will also destroy pathogens and produce antitoxins The lymphatic system is a drainage system and also forms which neutralise the toxins released by pathogens. part of the immune system. The system is responsible ▸▸ Blood clotting is a complex process during which for transporting a clear watery fluid known as lymph white blood cells form solid clots. A damaged blood which contains white blood cells, debris of other cells and vessel wall is covered by a fibrin clot to help repair bacteria. The system helps the body get rid of excess fluid the damaged vessel. Platelets form a plug at the site of and waste products through excretion of urine and faeces. damage. Plasma components known as coagulation factors respond to form fibrin strands which strengthen Function of the cardiovascular the platelet plug. This is made possible by the constant system supply of blood through the cardiovascular system. The cardiovascular system fulfils a number of important Key term functions, particularly during sport and exercise. ▸▸ The key function is to supply oxygen and nutrients Pathogen – a bacterium, virus or other to the tissues of the body via the bloodstream. During microorganism that can cause disease. exercise your body needs more of these so the cardiovascular system responds to meet these increased demands. When it can no longer meet these demands, The cardiac cycle muscle fatigue occurs and performance deteriorates. Your heart pumps (or beats) when the atria and ventricles ▸▸ The circulatory system also carries waste products work together. Both the atria and the ventricles contract from the tissues to the kidneys and the liver, and returns independently, pushing blood out of the heart’s chambers. carbon dioxide from the tissues to the lungs. During The process of the heart filling with blood followed by a exercise, muscles produce more carbon dioxide and contraction where the blood is pumped out is known as lactate and it is essential these are removed, otherwise the cardiac cycle. The electrical system of your heart is muscle fatigue will occur. the power source that makes this possible. ▸▸ The cardiovascular system is responsible for the distribution and redistribution of heat within your Blood flow through the heart body to maintain thermal balance during exercise. This Blood pressure is the pressure of the blood against the ensures that you do not overheat during exercise. walls of your arteries and results from two forces: Vasodilation of blood vessels near the skin – ▸▸ systolic pressure – the pressure exerted on your artery during exercise the part of the active muscles where walls when your heart contracts and forces blood out of Copyright © 2013. Pearson Education Limited. All rights reserved. gaseous exchange takes place increases through the heart and into the body dilation of arterioles, caused by the relaxation of the ▸▸ diastolic pressure – the pressure on the blood vessel involuntary muscle fibres in the walls of the blood walls when the heart is relaxed between beats and is vessels. This causes an increase in the diameter of filling with blood. blood vessels to decrease resistance to the flow During exercise your systolic blood pressure increases as of blood to the area supplied by the vessels. This your heart is working harder to supply more oxygenated decreases body temperature as heat within the blood blood to the working muscles. Your diastolic blood is carried to the body’s surface. pressure stays the same or decreases slightly. Vasoconstriction of blood vessels near the skin – blood vessels can temporarily shut down blood When blood pressure is measured, it is written with both flow to tissues. This causes a decrease in the blood the systolic and the diastolic pressure noted. The top vessel diameter. This leads to an increase in body number is the systolic pressure and the bottom number is the diastolic pressure, for example: ___ ​120 80 ​mm HG 47 Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Neural control of the cardiac cycle ventricle to contract at regular intervals (i.e. your regular Your heart’s electrical system (see Figure 2.5) is made up of heartbeat). This causes the blood to be pushed out of the three main parts. heart, either to the lungs or to the working muscles. ▸▸ Sinoatrial node (SAN) – located within the walls of the right atrium. The SAN sends an impulse or signal from the right atrium through the walls of the atria which causes Sinoatrial the muscular walls to contract. This contraction forces node (SAN) the blood within the atria down into the ventricles. ▸▸ Atrioventricular node (AVN) – located in the centre of the heart between the atria and the ventricles, and Atrioventricular acts as a buffer or gate that slows down the signal from node (AVN) the SAN. By slowing down the signal, the atria are able to contract before the ventricles which means the ventricles are relaxed (or open) ready to receive the Bundle of His blood from the atria at the top of the heart. ▸▸ Bundle of His and Purkinje fibres – specialist heart muscle cells responsible for transporting the electrical Left and impulses from AVN, and found in the walls of the right bundle ventricles and septum. At the end of the Bundle of His are branches Purkinje fibres thin filaments known as Purkinje fibres which allow the ▸▸ Figure 2.5: The heart’s electrical system Theory into practice In pairs, choose a single-person sport you both enjoy. 1 During the warm-up what changes occurred to your Take 8–10 minutes to perform a thorough warm-up and heart rate and breathing? then take part in your chosen activity for at least 20 2 During the main exercise what changes occurred? minutes at moderate intensity levels. At the end of the Think about how you felt: did you get hot? How did session spend approximately 5 minutes to cool down. your body adapt to control your temperature? What During each part of the activity, pay close attention to do think would have happened if you had exercised the changes that are taking place in your body. Get your at higher intensities? partner to record these for you, then swap roles. Check your knowledge of the cardiovascular system by identifying and listing the P aus e point key components of this system. Hint Describe the function of each component of the cardiovascular system. Extend Explain why each described component is important to sport and exercise. Assessment practice 2.1   Copyright © 2013. Pearson Education Limited. All rights reserved. 1 Identify the function of the Plan sinoatrial node.  (1 mark) Have I planned my answers based on the point I want to make? 2 Describe the function of red blood Have I written some notes on a blank page, including key words that cells.  (2 marks) should be included in my answers? 3 Identify the functions of the Do cardiovascular system.  (5 marks) Have I answered the simpler questions first, making sure I have enough time for the more complex questions? 4 Describe how the cardiovascular Have I allowed enough time to answer all the questions and to check system helps the body my answers? to thermoregulate in hot Review environments.  (4 marks) Have I re-read my answers and made any necessary changes? 48 Functional Anatomy Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  Learning aim C UNIT 2 Functional Anatomy C Anatomy of the respiratory system The respiratory system provides oxygen to all living tissue in your body, and removes waste products such as carbon dioxide, heat and water vapour. Your body’s ability to inhale and transport oxygen while removing waste products is critical to exercise: the better your body is at this, the better you will perform in sport. Location, anatomy and function of respiratory system components Air is drawn into your body via the nose and mouth, and passes through a series of airways to reach the lungs. This is referred to as the respiratory tract. The upper respiratory tract includes the nose, nasal cavity, mouth, pharynx and larynx; the lower respiratory tract includes the trachea, bronchi and lungs. The different parts of the respiratory system are shown in Figure 2.6 and examined in more detail in Table 2.4. Nasal cavity Mouth Pharynx Epiglottis Intercostal muscles (external) Trachea Larynx Section of ribs Cartilage rings Intercostal muscles Lungs (internal) Outer edge of lung surface Bronchus Copyright © 2013. Pearson Education Limited. All rights reserved. Bronchiole Lobar bronchi Alveoli Heart Pleural cavity Diaphragm Fibrous Pleural muscle region membrane of diaphragm ▸▸ Figure 2.6: The anatomy of the respiratory system 49 Pearson, et al. BTEC Nationals Sport and Exercise Science Student Book, Pearson Education Limited, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/chichester-ebooks/detail.action?docID=4770645. Created from chichester-ebooks on 2024-09-05 09:41:47.  ▸▸ Table 2.4: Parts of the respiratory system Component Description Nasal cavity Air enters the nasal cavity through the nostrils. Hairs filter out dust, pollen and other foreign particles before air passes into the two passages of the internal nasal cavity. Air is warmed and moistened before passing into the pharynx. A sticky mucous layer traps smaller foreign particles, which tiny hairs (cilia) transport to the pharynx to be swallowed. Pharynx (throat) A small tube approximately 10–13 cm from the base of the skull to the level of the sixth cervical vertebra. The funnel-shaped pharynx connects the nasal cavity and mouth to the larynx (air) and oesophagus (food) and is a passageway for food and air, so special adaptations are required to prevent choking when food or liquid is swallowed. Epiglottis The small flap of cartilage at the back of the tongue which closes the top of the trachea when you swallow to ensure food and drink pass into your stomach and not your lungs. Larynx (voice box) Has rigid walls of muscle and cartilage, contains the vocal cords and connects the pharynx to the trachea. It extends for about 5 cm from the level of the third to sixth vertebra. Lungs (lobes) The organs that allow oxygen to be drawn into the body. The paired right and left lungs occupy most of the thoracic cavity and extend down to the diaphragm. They hang suspended in the right and left pleural cavities straddling the heart. The left lung is smaller than the right. Trachea (windpipe) The start of the lower respiratory tract. It is about 12 cm long by 2 cm in diameter. It contains rings of cartilage to prevent it collapsing and is flexible. It travels down the neck in front of the oesophagus and branches into the right and left bronchi. Bronchus Carry air to the lungs, divided into the right and left bronchi formed by the division of the trachea. When inhaled air reaches the bronchi, it is warm, clear of most impurities and saturated with water vapour. Once inside the lungs, each bronchus subdivides into lobar bronchi: three on the right and two on the left. The lobar bronchi branch into segmental bronchi, which divide again into smaller and smaller bronchi. Overall, there are approximately 23 orders of branching bronchial airways in the lungs. Because of this branching pattern, the bronchial network within the lungs is often called the bronchial tree. (See Figure 2.6.)