Fundamentals of Anatomy and Physiology in Sports PDF

# Fundamentals of Anatomy and Physiology in Sports ## Chapter 7: Fundamentals of Anatomy Physiology in Sports ### Learning Objectives - Definition and Importance of Anatomy and Physiology in exercise and sports - Functions of Skeletal system, classification of bone and types of joints - Properties...

# Fundamentals of Anatomy and Physiology in Sports ## Chapter 7: Fundamentals of Anatomy Physiology in Sports ### Learning Objectives - Definition and Importance of Anatomy and Physiology in exercise and sports - Functions of Skeletal system, classification of bone and types of joints - Properties and Functions of Muscles - Structure and Function of Circulatory system and heart - Structure and Function of Respiratory system ### 7.1 Definition and Importance of Anatomy and Physiology in Exercise and Sports Anatomy is the science that deals with the structure of the body and the relationship between the body parts. The word anatomy is derived from the Greek words Ana, meaning apart, and tomy, meaning to cut. Hence, the word anatomy refers to dissection, and it can be defined as the science of the structure of a body learned by dissection. In other words, anatomy is the study of the shape and structure of the human body and body parts along with their relationship to one another. Anatomy and Physiology are branches of human biology that deal with specific areas of the human body. ### 7.1(a) Anatomy Anatomy is the study of an organism's bodily structure, especially as revealed through dissection and the separation of parts. Anatomy tells us the basic structure of various body parts and their inter-connected relationships. Anatomy is divided into the following categories: **Macro anatomy** is the study of the larger structures of the body, those visible without the aid of magnification. It deals with the large body structures such as heart, lungs, and bones. **Microscopic anatomy** is the study of those structures of the body that cannot be seen with the naked eye. Macro anatomy may further be subdivided into the following categories: 1. **Systemic Anatomy:** Systemic anatomy is the study of the working and structures of a discrete body system. It is the study of a group of structures that work together to perform a unique body function. For example, a systemic study of the muscular system would include all of the skeletal muscles of the body. 2. **Regional Anatomy:** Regional anatomy is the study of the interrelationships of all of the structures in a specific body region. Regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. For example, the study of an area of the body such as the abdomen would include a study of all organs, blood vessels, etc. in that part of the body. 3. **Surface Anatomy:** Surface anatomy is a study of external features of the body like the bony projections of the body that act as a landmark and help us to locate the other deeper structures. For example, skin, nails, hair, etc. Microscopic anatomy includes: 1. **Cytology** or the study of the internal structure of cells 2. **Histology** or the study of tissues (groups of cells) ### 7.1(b) Meaning of Physiology Human physiology is the study of bodily functions. Physiology is the science of the functions of living organisms and their parts. The word physiology is derived from the Greek words phys, meaning nature, and logio, meaning study of. Hence, the word physiology refers to the study of the human body and its functions and of the different parts and organs of the body, such as the detailed working and function of the skeletal system, respiratory system, and the circulatory. Here we understand and study how the human body responds to a given stimulus. Physiology is further divided into sub parts which are as follows: * **Human physiology:** This branch of physiology refers to the study of a specific organism, i.e., the human being. * **Cellular and systemic physiology:** Cellular physiology is the study of the function of cells while systemic physiology is the study of the function of the body's systems. **Definition:** Physiology is the science dealing with the study of human body functions. **Exercise Physiology:** is the study of how body's structures and functions are changed as a result of exercise. **Sports Physiology** is derived from exercise physiology. It applies the concept of exercise physiology to training the athlete and enhancing the athlete's sports performance. ### 7.1(c) Importance of Anatomy and Physiology in Sports and Exercise Anatomy and Physiology are interrelated concepts, while one focuses on bodily structure, the other highlights the significance of understanding bodily functioning properly. Thus, both concepts figure greatly in developing a central understanding of physical education. Without understanding anatomy and physiology, we cannot even think of their importance in physical education and sports. The knowledge of anatomy and physiology is essential to know physical education and sports from a scientific point of view. A physical trainer can improve the performance of his athletes by knowing the effect of exercises on the various body parts of his athletes.. The importance of anatomy and physiology in Physical Education and Sports are as follows: 1. **Helps in physical fitness:** Study of anatomy and physiology helps a sports person to understand the structure and functioning of different parts of the human body and to acquire a fit and healthy body, for example, building muscle strength, muscle endurance through appropriate exercises. 2. **Provides knowledge about body structure:** Knowing the strengths and weaknesses of one's body can help the sports person develop their strength in the field of games or sports that are suitable for them, considering their body structure. For example, designing exercises based on movement of joints like shoulder rotation, due to the presence of the ball and socket joint in the shoulder, and extension and flexion of the elbow due to the hinge joint in the elbow.. 3. **Provides knowledge about the functions of various organs of the body:** Knowledge of the capacity or functions of the various body systems like the cardiovascular system, the nervous system, muscular system, and excretory system is essential for imparting proper and beneficial training to the athletes. 4. **Helps in selection of games:** On the basis of the knowledge of body structure, a coach or player can choose an appropriate sport for the student. For example, weight lifting is more appropriate for short-statured students in comparison to volleyball and basketball which are better suited for students who are tall. 5. **Protects from sports injuries:** Injuries related to sports such as sprain, contusion, fracture, dislocation of joints, etc. are fairly common on the sports field. Sports equipment is designed to ensure safety on the basis of knowledge of anatomy. Designing protective equipment in games and sports to provide protection to the soft and delicate organs requires appropriate knowledge about the functions of bones, muscles, tendons and ligaments. 6. **Helps in the process of rehabilitation:** Injuries are common and natural on the sports field. Knowledge of ligaments, tendons and muscles helps in rehabilitation from the injuries sustained during the game or sport, and the injured player can recuperate enough to give a good performance again. For example, a physiotherapist who helps an injured sportsperson in recuperation and rehabilitation so that they can get back to the game. 7. **Helps in maintaining a healthy body:** Study of anatomy and physiology provides detailed knowledge about all body parts, their nature and function, and promotes good, safe, and healthy use of the body, for example, knowledge of anatomy provides information about good and bad posture while sitting, standing, lying down, running. 8. **Helps to learn about individual differences between male and female athletes:** Understanding the basic physiological differences between the body of male and female sports persons is essential because games and sports equipment is designed differently on the basis of these differences. For example, the differences in the structure of the shoulder among males and females is the reason for the difference in the weights of sports equipment such as shotput, discus, hammer, and javelin for males and females. ## 7.2 Function of Skeletal System, Classification of Bones, and Types of Joints ### 7.2(i) The Skeletal System The skeletal system consists of all the bones of the body. The hard and rigid structure of bones makes the skeletal system act as a framework that supports the body and gives it shape. The adult human skeletal system consists of 206 bones, as well as a network of tendons, ligaments and cartilage that connects them. The skeletal system performs vital functions - support, movement, protection, blood cell production, calcium storage and endocrine regulation that enable us to survive and carry out the physical demands of our body. Bones of the body: The human skeleton consists of 206 bones, which can be divided into two major parts. 1. **Axial Skeleton:** This part includes the bones of the Upper body parts. All these bones are for the protection and support of the important organs. * **Skull:** This consists of 22 bones: * Cranium with 8 bones * Face with 14 bones * **Ear:** 6 bones * **Rib cage:** 25 bones * **Vertebral Column:** 26 bones * **Hyoid bone:** 1 bone 2. **Appendicular Skeleton:** Includes the bones of the upper and lower extremities which attach the bones of the extremities to the axial skeleton. The appendicular group of bones can be studied under: * **Upper extremities** * **Lower extremities** **Upper extremities** consists of 64 bones as follows: * **Clavicle:** 2 bones * **Scapula:** 2 bones * **Humerus:** 2 bones * **Radius:** 2 bones * **Ulna:** 2 bones * **Carpals:** 16 bones * **Metacarpals:** 10 bones * **Phalanges:** 18 bones **Lower extremities** consists of 62 bones as follows: * **Pelvic bone:** 2 bones * **Femur:** 2 bones * **Patella:** 2 bones * **Tibia:** 2 bones * **Fibula:** 2 bones * **Tarsals (ankle):** 14 bones * **Metatarsals (instep):** 10 bones * **Phalanges (toe):** 28 bones ### Functions of the Skeletal System The functions of the skeletal system are as follows: 1. **Structure:** It serves as a supporting framework. Like the steel framework of a building, bones provide rigidity, which gives the body shape and supports the weight of the muscles and organs. Without this structure, the body would collapse in on itself, compressing the lungs, heart, and other organs, impairing their function. 2. **Movement:** There are three major systems involved in the mechanics of movement: the nervous system, muscular system, and skeletal system. The nervous system sends the electrical impulses that activate the muscles; the skeletal system provides the levers and anchors for the muscles to pull against. All skeletal muscles have an origin and insertion point. The origin is the anchor; the bone that remains immobile while the muscle works. The insertion is the bone that moves as the muscle works. For example, in the case of the biceps, the upper arm and shoulder are the origins (anchor) and the bones of the forearm are the insertion. Interestingly, the amount of power the muscle needs is directly related to the length of the bone (or lever) and where it is attached. This means that shorter people actually use less power to move than taller people because they have shorter bones, and the point of attachment is closer to the point of origin. 3. **Blood Cell Production:** Red and white blood cells are made in the red marrow of bones. At birth, and in early childhood, all bone marrow is red. As the person ages, about half of the body's marrow turns to yellow marrow which is composed of fat cells. In an adult human, a majority of the long bones contain yellow marrow, and the red marrow is only found in the flat bones of the hip, skull, and shoulder blades, the vertebrae, and at the ends of the long bones. 4. **Storage:** The body uses calcium and phosphorus for bodily processes like muscle contraction. Some of these minerals are found in our diet, but they are also taken from bone. When the body needs calcium, if there isn't a ready supply in the blood, the endocrine system releases hormones that initiate the process of taking calcium from bone and releasing it into the bloodstream. When there is a surplus of blood calcium, it's put back into the bone. This is why dietary calcium and vitamin D are so important. The body uses calcium constantly, and, if there isn't enough calcium in the diet, it will consistently take calcium from the bone to compensate, leading to osteoporosis. Having enough dietary calcium ensures that there is enough calcium for bodily functions and replenishes the backup stores in the bone. 5. **Protection:** The most obvious example of the protective properties of the skeletal system is the human skull. The vertebrae and ribs also have protective functions by encasing delicate structures like the spinal cord, heart, and lungs. The rib cage not only surrounds the organs of respiration, but it's also very flexible and is constructed to expand and contract with each breath. The bones of the skull are actually several flat plates joined together by sutures. These sutures allow the skull to pass through the birth canal and expand as the brain continues growing. The sutures fuse together in early childhood, forming the classic shape of the skull. The vertebrae are all irregularly shaped bones that provide both protection and flexibility for movement. There are also fibrous disks between each vertebra, which provide shock absorption. ### 7.2(ii) Classification of Bones Bones are classified on the basis of their shape and structure and can be classified into five types. These are present throughout as well in different sections of the skeletal system. They are as following: * **Long bones:** Each long bone is composed of a central shaft and two knob ends. A fiber sheet covers the whole area of a long bone, except where it joins with other bones. Bones of the upper and lower arm, thigh, and leg, and fingers and toes come under this type of bones. These bones help to facilitate movement and support the weight of the body, longer than they are wide, and include the femur (the longest bone in the body) as well as relatively small bones in the fingers. * Examples: Humerus, ulna, femur, tibia, fibula. * **Short bones:** These bones are cubeshaped and are composed of a central spongy bone covered by a thin layer of compact bone. These are as long as they are wide. The bones of ankles and wrist are examples of short bones. These bones help to provide stability and movement within the ankle and wrist joints, for example, the carpals in the wrist (scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid, and trapezium) and the tarsals in the ankles (calcaneus, talus, navicular, cuboid, lateral cuneiform, intermediate cuneiform, and medial cuneiform) are examples of short bones. * **Flat bones:** These bones are thin and flat. They are composed of a central layer of spongy bone fixed between two outer layers of compact bone. The bones of the ribs and shoulders are flat bones; flat bones in the skull (occipital, parietal, frontal, nasal, lacrimal, and vomer), the thoracic cage (sternum and ribs), and the pelvis (ilium, ischium, and pubis). The function of flat bones is to protect internal organs such as the brain, heart, and pelvic organs, they also provide large areas of attachment for muscles. * **Sesamoid bones:** These bones are seed-like and develop in the tendons like the patella, pisiform, etc. The function of this bone is to protect tendons and diminish friction and wear on joint surfaces. This type of bone is usually small and round and is found in the hands, feet, and knees. Sesamoid bones function to protect tendons from stress and wear. A common example of a sesamoid bone is the patella (kneecap). * **Irregular bones:** These bones have complex shapes as compared to other types. They are similar to short bones and flat bones. Bones of the spinal column and some bones of the skull are irregular bones. ### 7.2(iii) Types of Joints A joint is the place at which two or more bones meet in the skeleton of the body. Joints may be fixed or moveable. **Three Types of joints are Synovial Joints, Fibrous Joints, and Cartilaginous Joints.** Joints help in bringing about movements in different parts of the body. Let us see the classification of joints and anatomy of different types of Joints. Joints can be classified in different ways depending on: * The amount of mobility permitted by the joints * Type of tissue connecting the bones Each of these types can be further subdivided. Let's look at each classification individually. Depending on the degree of mobility permitted by the joint, we can classify them as: * **Fixed Joint or Synarthroses:** The word "syn" tells us that the bones are fused and therefore permit minimal or no movement. These joints are fibrous joints which means that the binding tissue between two bones is "fibrous" in nature. Example of a fixed joint is the sutures between skull bones. This type of joint is held together by only a ligament. Examples are where the teeth are held to their bony sockets and at both the radioulnar and tibiofibular joints. * **Slightly Moveable Joint or Amphiarthroses:** This joint permits slight mobility that is more than what is seen in a fixed joint. The binding tissue in this type of joint is cartilaginous in nature. Example of a slightly moveable joint is those found between intervertebral discs. Cartilaginous. These joints occur where the connection between the articulating bones is made up of cartilage, for example, between vertebrae in the spine. * **Freely Moveable Joint or Synovial Joints:** These joints permit maximum movement between the bones involved. They are also called as "diarthroses" and are further classified into 6 types depending on the kind of movements possible. * **Synovial (diarthrosis)** are by far the most common classification of a joint within the human body. They are highly moveable and all have a synovial capsule (collagenous structure) surrounding the entire joint, a synovial membrane (the inner later of the capsule) which secretes synovial fluid (a lubricating liquid) and cartilage known as hyaline cartilage which pads the ends of the articulating bones. There are six main types of moveable joints: * Hinge joints * Pivot joints * Ball and Socket joints * Gliding joints * Saddle and Condyloid joints **Hinge joints:** These joints allow a forward and backward motion in one plane, like the motion of a door on its hinges; movement is limited to a single direction. The joints at the knee and elbow are hinge joins. This joint permits bending and straightening movements along one plane. Examples of hinge joints include the elbow, knee, ankle, and joints between the bones of the fingers and toes. **Pivot joint:** This joint gives a rotation motion around a single axis such as the movement of the head from side to side. One bone is encircled by a ring formed by the other bone at the joint and a ligament,. The bone that pivots may either rotate within the ring or the ring may rotate around the bone. The joint between the first and second cervical vertebrae near the base of the skull is an example of a pivot joint. It allows the head to turn from side to side. **Ball and Socket Joints:** Ball and socket joints involves two bones, joint are made up of a large round end of a long bone, which fits into the hollow of another bone or possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and-socket joints are the shoulder and hip joints. This kind of joint is generally found in large bones such as the shoulder joint and hip joint.. **Gliding joint:** In gliding joints, the articular surfaces glide over each other. Joints between the carpel bones and between tarsal bones are gliding joints. This joint is very similar to the ball and socket joint but without rotation. It allows movements only in two axes. Example of this is the wrist joint. **Saddle and Condyloid joints:** The movement in these joints takes place round two axes, therefore allowing the different movements like flexion, extension, abduction, adduction, and circumduction. Wrist joints and finger joints are good examples of Saddle and Condyloid joints. ## 7.3 Properties and Functions of Muscles ### 7.3(a) Properties of Muscles There are about 700 major and minor voluntary muscles in the body, all of which come together to constitute the muscular system of the human body. Each muscle is made up of thousands of long and normal muscle cells called muscle fibers. These muscle fibers are arranged in bundles and enclosed within a tough layer of connective tissue called epimysium. Each muscle fiber is made up of very large numbers of microscopic threads called myofibrils. Myofibrils consist of protein molecules called actin and myosin. Muscles have four major functional characteristics that explain their functionality in a nutshell: Contractility, excitability, extensibility, and elasticity. * **Contractility:** In the case of skeletal muscles, muscle cells contract when stimulated by neural input; smooth and cardiac muscles do not require this input. When a muscle is excited, the impulse travels along various membranes of the cell. This then goes to its interior. Calcium ions flow forward and bind to a protein molecule called troponin, leading to sequential changes in shape and position of the associated proteins tropomyosin, myosin, and actin. The upshot is that myosin binds to small strands within the cell called myofilaments and pulls them along, causing the cell to shorten, or contract. Since this is going on simultaneously and in a coordinated fashion in many thousands of myelocytes at the same time, the muscle as a whole contracts. * **Extensibility:** Most of our body cells lack the capacity to stretch. Attempting to do so only damages or destroys them. Our long cylindrical muscle cells, however, are different. Muscle cells contract, and in order to retain this ability, they must accordingly possess extensibility. Our muscle cells can be stretched to 3 times their contracted length without rupturing. This is important because in coordinated movement, so-called agonistic muscles operate such that one is long thinning white the other is contracting. Best example is, when you run the hamstring muscle at the back of your thigh which contracts while your quadriceps muscles are extended and conversely. * **Elasticity:** When something is described as elastic, which can be stretched or contracted by the same amount above or below its resting or default length without damaging it, it can be said to have elasticity. Anything possessing the quality of elasticity will return to the resting length once the stimulus for stretching or contraction is removed. Your muscles require this property of elastic recoil for them to do their jobs. If your biceps muscles failed to recoil to their resting length after being stretching during a series of curling exercises, they would become slack. Slack muscles with no tension are unable to generate any force and are therefore useless as levers. * **Excitability:** Muscle cells must be stimulated, most often by the nerves supplying blood to it. Nervous impulses cause the release of the neurotransmitter acetylcholine at the nerve-muscle junction and the acetylcholinic activates receptors on the surface of the muscle cell. This results in an influx of positively charged sodium ions into the muscle cell and a depolarization of the muscle cell membrane, which in the resting state is quite negatively changed. If the membrane becomes sufficiently depolarized, and leads to creating potential results, the muscle cell is the "excited" from an electronical stand point. ### 7.3(b) Function of Muscles There are about 700 named muscles that make up roughly half of a person's body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons and nerves. There are three types of muscles found in our body according to their structure, that is, Visceral muscle, Cardiac Muscle, and Skeletal Muscle: 1. **Visceral Muscle:** Visceral muscle is found inside the organs like the stomach, intestines, and blood vessels. The weakest of all muscles tissues, visceral muscle makes organs contract to move substances through the organ. Because visceral muscle is controlled by the unconscious part of the brain, it is known as *involuntary muscle.* It cannot be directly controlled by the conscious mind. The term "smooth muscle" is often used to describe visceral muscle because it has a very smooth, uniform appearance when viewed under a microscope. * **Function of Visceral Muscle:** * It controls slow, involuntary movements such as the contraction of the smooth muscles tissues in the wall of the stomach and intestines. * The muscle of the retinas contracts and relaxes the blood pressure and the blood flow in the body. * It sends the sustenance of the body through the organs. 2. **Cardiac Muscle:** This type of muscle is only found in the heart. Cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle tissue cannot be controlled consciously, so it is an *involuntary muscle*. White hormones and signals from the brain adjust the rate of contraction, cardiac muscles stimulates itself to contract. The natural pacemaker of the heart is made of cardiac muscle cells to contract. Because of its self-stimulation, cardiac muscle is considered to be alto-rhythmic or intrinsically controlled. * **The cells of cardiac muscle tissue are striated**, that is, they appear to have light and dark stripes when viewed under a light microscope. The arrangement of protein fibers inside of the cells causes these light and dark bands. Striations indicate that a muscle cell is very strong. * **Function of Cardiac Muscle:** * Cardiac muscle tissue plays an important role in the contraction of the atria and ventricles of the heart. * This muscle causes the rhythmical beating of the heart. * It helps in circulating the blood and its contents throughout the body. 3. **Skeletal Muscle:** Skeletal muscle is the only *voluntary muscle tissue* in the human body - it is controlled consciously. Every physical action that a person consciously performs (e.g., walking, talking, or writing) requires skeletal muscle. The function of skeletal muscle is to contract to move parts of the body closer to the bone that the muscle is attached to. Most skeletal muscles are attached to two bones across a joint, so the muscle serves to move parts of those bones to each other. Skeletal muscle cells form when many smaller progenitor cells lump themselves together to form long, straight, multinucleated fibers. Striated just like cardiac muscle, these skeletal muscle fibers are very strong. Skeletal muscle derives its name from the fact that these muscles always connect to the skeleton in at least one place. * **Function of Skeletal Muscle:** * The skeletal muscles functions in pairs to bring about the coordinated movements of the trunk, jaws, eyeballs, etc. * It is directly involved in the breathing process. ## 7.4 Structure and Function of Circulatory system and Heart ### 7.4(i) Introduction to Circulatory System and Heart The circulatory system mediates the continuous movement of all body fluids. Its principal functions are the transport of oxygen and nutrients to the tissues and transport of carbon dioxide and other metabolic waste products from the tissues. The circulatory system is also involved in temperature regulation and the distribution of molecules such as hormones and cells such as those of the immune system. The circulatory system has two functional components, the blood vascular system and the lymph vascular system. The blood vascular system comprises a circuit of vessels through which flow of blood is maintained by the continuous pumping of the heart. These blood vessels are not rigid tubes but dynamic structures that pulsate, constrict, and relax, and even proliferate (under the influence of many hormones and factors) as demanded by the changing needs of the human body. The arterial system provides a distribution network to metabolites between the tissues and blood. The venous system returns blood from the capillaries to the heart. In contrast, the lymph vascular of system is mainly a passive draining system for returning extra vascular fluid (the lymph) to the blood vascular system. The lymph vascular system has no intrinsic pumping mechanism. ### 7.4(ii) Functions of the Heart 1. **Pumping Blood to the Lungs:** Blood from the body that enters the right side of the heart contains carbon dioxide, a gaseous waste the cells produce in creating energy. Blood enters the right atrium through the superior vena cava and inferior vena cava. The atrium fills with blood and then contracts, forcing the blood through the tricuspid valve into the right ventricle. After the ventricle is filled, pressure pushes the tricuspid valve to close and the pulmonary valve, leading to the pulmonary artery, to open. The ventricle contracts and the blood enter through the pulmonary artery and into the lungs. In the lungs, carbon dioxide is removed from the blood and oxygen is added. The oxygenated blood then flows through the pulmonary veins to the left side of the heart. 2. **Pumping Blood through the Body:** Oxygenated blood from the lungs enters and fills the left atrium. The atrium then contracts which squeezes the blood through the mitral/ bicuspid valve into the left ventricle. After blood fills the ventricle, the mitral valve closes and the aortic valve opens. Blood pours into the aorta and flows through arteries to the body tissues.. 3. **Regulating Blood Pressure:** Blood in the circulatory system, like water in the pipes of a water system, is always under pressure. Blood pressure refers to the force with which the blood pushes the walls of the arteries. That force drives blood from the heart to all parts of the body. Each person's blood pressure reflects the amount of blood in the body, the strength and rate of the heart's contractions, and the elasticity of the arteries. As the heart pumps in cycles, pressure in the arteries rises and falls during systole and diastole. Contraction of the heart produces systolic blood pressure, and relaxation produces diastolic blood pressure. The heart helps regulate blood pressure by producing a hormone that helps the kidneys in eliminating salt from the body. High blood pressure can injure heart, brain and kidneys and also lead to heart failure. 4. **Regulating the Heart Rate:** Both sides of the heart pump blood at the same time. As the right ventricle contracts and sends blood to the lungs, the left ventricle contracts and squeezes blood out to the body. The heart's cycle of activity has two periods, systole and diastole. Systole occurs when the ventricle contracts, and diastole when they relax. One complete contraction and relaxation of the heart muscle makes up one heart beat. ### Components of the blood vascular system Three major types of blood vessels found in the body are the arteries, veins and capillaries. * **Arteries:** Arteries are the vessels that carry blood away from the heart. * **Veins:** Veins are the vessels that bring back blood towards the heart. * **Capillaries:** Capillaries are the tiny microscopic vessels connecting the arteries tothe veins. The arteries are said to "branch," "diverge," or "fork" as they carry blood away from the heart. Veins by contrast and said to "form," "merge" or serve as "tributaries," as they carry blood towards the heart. **Blood:** Blood is a special kind of fluid which acts as a medium of transporting nutrients and gases from one part of the body to another. **Important functions of Blood:** * It transports O2 from the lungs to the tissues and CO2 from the tissues to the lungs. * It carries food material absorbed from the intestine to the tissues. * It carries the waste products of cellular activity and corries them to kidneys, lungs and intestine for excretion. * It carries hormones, vitamins and other chemicals to the place of need. * It helps to maintain body temperature. * It helps maintain water balance in the body. **Heart Rate:** Heart rate is the number of pumping of heart in one minute. It varies from person to person. **Cardiac Output:** Cardiac output = stroke volume X Heart Rate. It is about 5 to 6 liters it base level. **Blood Pressure:** It is the force exerted by the blood on the walls of blood vessels. ## 7.5. Structure and Function of Respiratory System The primary organs of the respiratory system are lungs, which function to absorb in oxygen and expel carbon dioxide as we breathe. The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. Various parts of the respiratory system are: * **Nose:** As we breathe, oxygen enters the nose or mouth and passes the sinuses, which are hollow spaces in the skill. * **Trachea:** The trachea, also called the wind pipe, filters the air that is inhaled. It branches into the bronchi, which have two tubes that carry air into each lung. The bronchial tubes are linked with tiny hairs called cilia. Cilia move back and forth, carrying mucus up and out. Mucus, is sticky fluid, collects dust, germs and other matter that has invaded the lungs. * **Lungs:** The bronchial tubes lead to the lobes of the lungs. The right lung has three lobes, and left lungs have two, according to the American Lung Association. The left lung is smaller to allow room for the heart, according to the National Heart, Lung and Blood Institute. Lobes are filled with small, spongy sacs called alveoli, and this is where the exchange of oxygen and carbon dioxide occurs. The alveoli walls are extremely thin (about 0.2 micrometers). These walls are composed of a single layer of tissues called epithelial cells and tiny blood vessels called pulmonary capillaries. ### Functions of Respiratory System The following are the key functions of the respiratory system: 1. Three bony projections present in the nose filter the air we breathe in. 2. Eustachian tubes equalize the air pressure between ear, nose and throat. 3. Larynx avoids the food to enter in the respiratory tract. 4. Trachea or wind pipe forms a passage for air to travel from larynx to lungs. The inner wall of wind pipe traps the particles of dust and micro organisms. 5. Bronchi help in gaseous exchange within the lungs. 6. Lungs interchange the two gases that is oxygen and carbon dioxide. ### Function of Respiratory System The process of physiological respiration includes two major parts: external respiration and internal respiration. External respiration, also known as breathing, involves both bringing air into the lungs (inhalation) and releasing air to the atmosphere (exhalation). During internal respiration, oxygen and carbon dioxide are exchanged between the cells and blood vessels. Respiration begins at the nose or mouth, where oxygenated air is brought in before moving down the pharynx, larynx, and the trachea. The trachea branches into two bronchi, each leading into a lung. Each bronchus divides into smaller bronchi, and again into even smaller tubes called bronchioles. At the end of the bronchioles are air sacs called alveoli, and this is where gas exchange occurs. The primary organs of the respiratory system are lungs, which function to absorb in oxygen and expel carbon dioxide as we breathe. The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. Various parts of the respiratory system are: * **Mouth and nose:** Openings that pull air from outside your body into your respiratory system. * **Sinuses:** Hollow areas between the bones in your head that help regulate the temperature and humidity of the air you inhale. * **Pharynx (throat):** Tube that delivers air from your mouth and nose to the trachea (windpipe). * **Trachea:** Passage connecting your throat and lungs. * **Bronchial tubes:** Tubes at the bottom of your windpipe that connect into each lung. * **Lungs:** Two organs that remove oxygen from the air and pass it into your blood. From your lungs, your bloodstream delivers oxygen to all your organs and other tissues. Muscles and bones help move the air you inhale into and out of your lungs. Some of the bones and muscles in the respiratory system include your: * **Diaphragm:** Muscle that helps your lungs pull in air and push it out. * **Ribs:** Bones that surround and protect your lungs and heart. When you breathe out, your blood carries carbon dioxide and other waste out of the body. Other components that work with the lungs and blood vessels include: * **Alveoli:** Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. * **Bronchioles:** Small branches of the bronchial tubes that lead to the alveoli. * **Capillaries:** Blood vessels in the alveoli walls that move oxygen and carbon dioxide. * **Lung lobes:** Sections of the lungs - three lobes in the right lung and two in the left lung. * **Pleura:** Thin sacs that surround each lung lobe and separate your lungs from the chest wall. * **Some of the other components of your respiratory system include:** * **Cilia:** Tiny hairs that move in a wave-like motion to filter dust and other irritants out of your airways. * **Epiglottis:** Tissue flap at the entrance to the trachea that closes when you swallow to keep food and liquids out of your airway. * **Larynx (voice box):** Hollow organ that allows you to talk and make sounds when air moves in and out. ## Multiple Choice Questions 1. **What is the function of the Respiratory System?** * (a) To take in glucose and convert it into usable energy. * (b) Send signals through the spinal cord and brain to tell other parts of the body what to do. * (c) Take waste products and take them out of the body. * (d) To allow gas exchange to provide parts of the body with oxygen. 2. **What is the pathway air takes during inhalation and exhalation?** * (a) Mouth, Trachea, Stomach, Lungs * (b) Mouth, Lungs, Trachea * (c) Lungs, Mouth * (d) Mouth, Trachea, Lungs