Anatomy and physiology for exercise PDF

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Summary

Notes on anatomy and physiology of the human body including circulatory and respiratory systems, muscles and bones....

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Unit 1| Section 1| Anatomy and physiology for exercise Welcome to ‘anatomy and physiology for exercise’.

When working with individuals in a health and exercise-related environment, it’s important to be familiar with the underlying anatomical and physiological principles of exercise. There are eight learning outcomes for this unit:

Understand the structure and function of the circulatory system, the respiratory system, and the skeleton.

Understand the joints in the skeleton, the muscular system, and the life-course of the skeletal system and its implications for special exercise populations.

And, finally, understand energy systems and the nervous system and their relation to exercise.

You can find out how to navigate this unit and how everything works by pressing the ‘help’ button at the bottom of the screen, which is the one with the ‘question mark’ icon on it.

We hope you enjoy your studies.

Unit 1| Section 1| The structure and function of the circulatory system In this section you will be guided through: the location, function and structure of the heart, and the flow of blood through it; systemic and pulmonary circulation; the structure and functions of blood vessels; and the definition of blood pressure and its classifications.

Unit 1| Section 1| Location and function of the heart The heart is a muscular pump located in the upper chest, just left of centre, behind the sternum. It sits between the lungs in a specially designed cavity. Its primary purpose is to pump blood to the lungs and also around the rest of the body.

Blood is essential to life and without it the tissues would be starved of oxygen and nutrients, while waste products would accumulate. The bloodstream is a closed circulatory loop and

needs a mechanism to maintain the flow; this is the heart’s role. It’s vital to sustaining life and so is referred to as one of the ‘vital organs’.

Unit 1| Section 1| Anatomy of the heart The heart consists of four chambers: the upper two smaller chambers are called atria, the two larger, lower chambers are called ventricles. Blood always travels from A to V (alphabetically). The ventricles have thicker more muscular walls than the atria, as they are required to push blood out with sufficient pressure to pass through the whole body.

Unit 1| Section 1| Movement of blood through the heart Blood enters the heart via the left and right atria, where it is pushed into the ventricles before being forcefully ejected in to the body’s tissues.

Left atrium: receives oxygen-rich blood from the lungs via the pulmonary vein. Left ventricle: receives blood from the left atrium, before ejecting it into the aorta (main artery) to supply the rest of the body’s tissues with blood and oxygen. Right atrium: receives returning, deoxygenated blood from the body’s tissues via the superior and inferior vena cava (main veins). This is then pumped into the ventricle. Right ventricle: receives blood from the left atrium, before ejecting it into the pulmonary vein on its way back to the lungs, where it will receive fresh oxygen and offload unwanted carbon dioxide.

Unit 1| Section 1| Systemic and pulmonary circulation The cardiovascular system is made up of the pulmonary and systemic circulations. The pulmonary circulation is the blood flow from the right ventricle to the left atrium, whereas the systemic circulation describes the flow of blood from the left ventricle to the right atrium via the tissues of the body.

Pulmonary circulation is the blood supply from the right ventricle to the left atrium via the lungs. Blood flow to the lungs passes through the pulmonary artery returning to the heart via the pulmonary vein. Systemic circulation carries blood from the left ventricle to the tissues via a large artery called the aorta. Blood returns to the right atrium via a large vein called the vena cava. To accommodate blood flow from both the upper and the lower body, the vena cava is comprised of both superior and inferior portions.

Unit 1| Section 1| Pulmonary circulation Pulmonary circulation involves the blood flow between the heart and the lungs. So starting in the heart, blood leaves the right ventricle, through the pulmonary artery, reaches the lungs, leaves the lungs through the pulmonary vein, and re-enters the heart in the left atrium.

Unit 1| Section 1| Structure and function of blood vessels There are three major category of blood vessel; arteries, veins and capillaries.

Unit 1| Section 1| Arteries    

Carry blood under high pressure. Thicker walls. More elastic. More smooth muscle.

Small arteries called arterioles help control blood flow in to the tissues.

Unit 1| Section 1| Veins     

Carry blood under low pressure. Thinner walls. Less elastic. Less smooth muscle. Non-return valves.

Small vessels called venules carry blood from the tissues in to the veins.

Unit 1| Section 1| Capillaries  

Smallest and most numerous blood vessels. Thin walls allow efficient exchange of materials.

Unit 1| Section 1| Structure and function of blood vessels Arteries are adapted to cope with blood under relatively high pressure and do not need nonreturn valves; the pressure alone is enough. Veins carry blood on the return journey back to the heart, when the pressure is relatively low. Capillaries are found in almost every tissue in

the body, and have the thinnest walls of any blood vessel. This allows for the efficient exchange of materials.

Unit 1| Section 1| Blood pressure We’ve talked already about the how blood vessels are adapted to cope with the demands placed on them by differing pressures, and most people will be familiar with having their blood pressure taken by a doctor. In this context, blood pressure is ‘a measure of the force that the blood applies to the walls of the arteries as it flows through them.’

This reading consists of two numbers; one represents the pressure while the heart is contracting (or ‘beating’) and the other while it is relaxing. These are referred to as systolic and diastolic blood pressure and the standard units of measurement are millimetres of mercury.

Unit 1| Section 1| Blood pressure classifications Blood pressure measurement can be used to determine an individuals’ level of risk of experiencing certain cardiovascular conditions such as cardiovascular disease (CHD) or stroke. Average resting blood pressure is 120/ 80 mmHG (millimetres of mercury). Individuals with blood pressure over 144/94 should be encouraged to see their doctor prior to beginning physical activity programmes.

Unit 1| Section 1| Circulatory system – summary We’ve seen that the circulatory system is divided into three parts: the blood, the heart and the blood vessels. Blood vessels are the transport system for the blood from the heart to the rest of the body and back again, and although they’re divided into different categories, it’s important to remember that they’re all linked in a continuous loop.

We’ve also looked at the measure of the force that the blood applies to the walls of the arteries as it flows through them. This is blood pressure. And you should now be able to recognise the systolic and diastolic blood pressure classifications.

Unit 1| Section 2| The structure and function of the respiratory system    

Structure and function of the respiratory system. Passage of air through the respiratory tract. Main muscles involved in breathing. Process of gaseous exchange of oxygen and carbon dioxide.

Unit 1| Section 2| Structure of the respiratory system Air is breathed in via the mouth and nose , through the following structures:  Pharynx – the region at the back of the throat where the passages of the nose and mouth meet, and above where the digestive and respiratory passages separate.  Larynx – the respiratory structure responsible for speech.  Trachea – a rigid tube supported by cartilaginous rings. Diameter is controlled by smooth muscle action.  Bronchi – branch from the trachea into the left and right lungs. Share similar cartilaginous and smooth muscle properties to the trachea.  Bronchioles – narrow passages (< 1.0mm) that carry air from the bronchi in to the alveoli of the lungs.

Unit 1| Section 2| The alveoli Alveoli are small air sacs with thin walls covered by a network of tiny capillaries. They are the site at which atmospheric oxygen is exchanged for carbon dioxide (a waste product) contained in the blood.

Unit 1| Section 2| Gas exchange in the alveoli Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Within biological organisms this usually involves movement across a cell membrane, such as the walls of the alveoli. Oxygen diffuses from the inhaled air into the relatively deoxygenated blood, which has been pumped to the lungs from the right hand side of the heart. In contrast, blood entering the lungs carries carbon dioxide, a waste product of aerobic energy production. As inhaled air contains little or no carbon dioxide, the gas will tend to diffuse out of the bloodstream and into the alveoli, before being exhaled.

Unit 1| Section 2| Respiratory musculature and mechanics During inhalation, the chest cavity expands; the resulting drop in internal pressure forces atmospheric air in and the lungs inflate. Expansion of the chest cavity is primarily achieved through the action of the intercostal muscles and the diaphragm.

Unit 1| Section 2| Respiratory musculature and mechanics The intercostals muscles lift the costal bones (ribs) causing an increase in the volume of the rib cage. As the diaphragm contracts, it flattens causing a further increase in the volume of the chest cavity.

Unit 1| Section 2| Respiratory mechanics Starting with inhalation, the diaphragm contracts, forcing it to flatten downwards, while the intercostals muscles lift up the rib cage. This causes the volume of the rib cage to increase, which lowers the internal air pressure, which in turn forces surrounding air into the lungs. Then, to start exhalation the diaphragm relaxes, moving it upwards while the intercostals also relax, lowering the rib cage. This decreases the volume of the rib cage and air is forced out of the lungs again.

Unit 1| Section 2| Respiratory system – summary The main functions of the respiratory system are the intake of oxygen into the body and the removal of carbon dioxide from the body.

We’ve seen how air enters the body and how muscles are involved in breathing. And you should now be able to describe how oxygen passes into the blood while at the same time carbon dioxide passes back into the lungs to be exhaled. Remember, this process is called gaseous exchange.

Unit 1| Section 3| Introducing the skeletal system In this section we will be investigating the skeletal system, the bones and joints of the body and how they play an integral role in human movement and function.

The skeletal system consists of a number of different materials including bone, cartilage and ligaments. We will begin by reviewing the various functions that the skeleton provides, the names of the major bones, the different structures contained within the divisions known as the axial and appendicular skeleton and the different classifications of bone.

Looking a little deeper inside the bone’s outer surface we will learn about the internal structure of a long bone and how this solid substance grows and develops. Then finally, we will take a look at how the spine is constructed; its five distinct divisions and the various shapes and bends that can develop within both normal and abnormal spinal positioning.

Unit 1| Section 3| Functions of the skeleton First and foremost the skeleton serves as a rigid, bony framework for the rest of the other tissues, organs and structures to connect and be anchored to.

Certain areas of the skeleton provide protection to the vital organs. The ribs protect the heart and lungs, the pelvis protects our reproductive anatomy and the cranium encases the brain.

The longer bones serve as a system of levers that create movement and locomotion. The muscles, which are anchored to the bones, help generate the forces needed to move the bones that provide this movement. At the centre of the bones, within the marrow, the body produces both red and white blood cells. Last, but not least the bones themselves are composed of a number of different minerals and serve as a storage site, especially for calcium.

Unit 1| Section 3| Bone anatomy Starting at the top we have the pelvis, followed by the femur, then the patella at the knee joint. The tibia is slightly higher up the leg than the fibula, as it forms part of the knee joint where the fibula doesn’t. The tarsals are in the ankle. The metatarsals make up the rest of the foot and the phalanges form the toes.

Unit 1| Section 3| Skeletal divisions It is useful to break the skeleton down into its two major divisions, known as the axial and the appendicular skeleton.

The axial skeleton forms the central barrel that the limbs are attached to. And it’s the skull, spine and ribs that make up this central structure. The axial skeleton doesn’t provide much in the way of movement, but the spine itself does allow for a limited amount.

The appendicular skeleton includes all other segments or appendages that hang off the central barrel and provide the majority of motion involved in locomotion. This includes the pelvis, legs and feet, as well as the shoulder girdle, arms and hands.

A useful comparison to remember that an axle is the central rod that anchors the wheels on a car, just like the axial skeleton serves as the anchor for the moving limbs.

Unit 1| Section 3| Axial or appendicular skeleton? Axial Skeleton: Ribs; Thoracic vertebrae; Cranium; Coccyx Appendicular Skeleton: Radius; Metatarsals; Clavicle; Ischium

There are a couple of tricky ones here. The Coccyx sits at the bottom of the spinal column and is classed within the axial skeleton. But the Ischium, the lower part of the pelvis, is in the appendicular skeleton, along with the clavicle, radius and the metatarsals.

Unit 1| Section 3| Bone classification Classificatio n Long bones

Description

Examples

Long bones have a greater length than width and consist of a shaft with normally two extremities. They contain mostly compact bone in their diaphysis and more cancellous bone in their epiphysis. (and principally act as levers). Short bones are normally about as long as they are wide. They are usually highly cancellous, which gives them strength with reduced weight.

Humerus, femur, fibula, tibia, ulna, radius, metacarpals, metatarsals, phalanges Carpals and tarsals

Flat bones

Flat bones are thin cancellous bone sandwiched between two compact layers. They provide protection and large areas for muscle attachment.

Scapula, cranial bones, costals (ribs), sternum and ilium

Irregular

Irregular bones form very complex shapes and therefore cannot be classified within the previous groups.

Vertebrae and calcaneus

Sesamoid (‘seed-like’)

Sesamoid bones develop within particular tendons at a site of considerable friction or tension. They serve to improve leverage and protect the joint from damage.

Patella (kneecap)

Short bones

Unit 1| Section 3| Bone structure and category The carpals in the wrist and tarsals in the feet are a similar width and length. The patella is a sesamoid bone, as it is encapsulated by tendons. The phalanges in the fingers and toes are small, but in terms of their shape they are longer than they are wide and so are long bones. The vertebrae of the spine are a more complex shape and fall into the irregular bone category.

Unit 1| Section 3| Long bone structure Hyaline cartilage – a thin layer of this smooth, tough connective tissue covers the ends of long bones at the meeting points between adjoining bones. The cartilage prevents wear and tear on the bone and allows for smooth motion at the joint. Epiphysis – the expanded portion at the end of each bone that allows for a larger articulating surface area to help spread out the forces experienced at the joint. Diaphysis – the narrower, strong shaft of bone that connects the two ends and houses the medullary cavity.

Cancellous bone – the porous bone that is found within the epiphyses that provides an element of elastic strength to the bone. Epiphyseal growth plate – a narrow band of bony tissue that is the site of rapid bone growth during childhood. It is largely dormant in adulthood when full bone length has already been reached. Compact bone – the dense bony tissue that forms the outermost surface of bones and gives the diaphysis its strength despite its narrow structure. Periosteum – a tough, fibrous outer membrane that covers the whole surface of the bone and provides a strong bonding layer for connective tissues, like ligaments and tendons. Medullary cavity – the cavity within the shaft of the long bone that contains blood vessels and bone marrow. The marrow is the site of blood cell formation in the body.

Unit 1| Section 3| Bone growth Bone growth is known as ossification.  

Osteoclasts – clear bone away. Osteoblasts – build bone.

Factors that affect ossification include:    

Nutrition. Exposure to sunlight. Hormonal secretions. Physical activity.

Unit 1| Section 3| Curves of the spine The spine is composed of five distinct sections, the ‘cervical’ in the neck that supports the skull, the ‘thoracic’ which is attached to the ribs, the ‘lumbar’ between the ribs and pelvis, the ‘sacrum’ which creates joints with the pelvis, and finally the ‘coccyx’ which is considered to be our residual tailbone. The spine is composed of 33 vertebrae, though 9 are fused towards the base and don’t allow for any motion. This leaves 24 moveable vertebrae. The cervical region has 7 vertebrae, the thoracic has 12 and the lumbar has 5. In general terms, the vertebrae are smallest at the top of the vertebral column beneath the skull and increase in size moving down the spine to the 5th lumbar vertebrae at the base. The fused, immobile vertebrae make up the remaining sections, 5 within the sacrum and 4 within the coccyx. They form a strong, sturdy base that’s able to transfer forces between the upper and lower body.

As a general rule the smaller, uppermost vertebrae have the greatest range of motion through flexion, extension, lateral flexion and rotation, with less in the thoracic and less again in the lumbar. The lumbar vertebrae support the most bodyweight and so they have the greatest role in stability and strength, hence their larger size and more limited range of movement.

Unit 1| Section 3| Postural deviations Neutral spine A neutral spine is the term used to describe a slight backward curve or arch in the lower back and a slight forward curve in the mid back. This position, which will vary from one individual to the next, seems to be the ideal position to decrease stress on passive structures of the body, such as the vertebrae and ligaments. This is therefore an ideal postural position to teach those participating in physical activity to help reduce the risks of lower back pain. Lifting in this neutral spine will help spare the stress on passive structures and teach the abdominal and hip musculature to hold the body in this optimal position.

Common postural abnormalities • lordosis (excessive lower back curvature) • kyphosis (excessive mid-back curvature) • scoliosis (a lateral deviation of the spine)

These abnormalities increase stress on the spine and surroundin...