Unit 3 anatomy and physiology (muscles)


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Unit 3 anatomy and physiology (muscles)

  1. 1. Label the diagram with as many muscles as you know.• Gluteus Maximus• Biceps• Triceps• Abdominals• Pectorals• Quadriceps• Hamstring• Deltoid• Sternohyoid• Erector Spinea• Trapezius• Oblique• Soleus• Gastrocnemius• LatissimusdorsiMuscles and Movement:Function of Muscles:All movement happen as a result of the shortening (contracting) and lengthening(expanding of muscles). The muscles enable us to move our body party Give us our individual shape Protect and keep our organs in place Enable us to maintain good posture Help in the circulation of blood Generate body heat when they contract
  2. 2. Types of Muscle:There are 3 main types of muscles in the body. Each type has a special purpose.Smooth or involuntary muscle: found in the bowel, the gut and internal guts.There is no direct control of this muscle – it works automatically.Cardiac Muscle: cardiac or heart muscle is specialized muscle that contractsconstantly and automatically. Some factors can effect the speed of thecontractions such as exercise and the release of hormones such as adrenaline.Skeletal Muscle: skeletal muscles are the ones that can easily be seen as a shapeunder the skin. Unlike smooth muscle or cardiac muscle, we can control skeletalmuscles and because of this it is sometimes known as voluntary muscles.Muscles and SportSuccessful sporting action depends on our muscles working together to produceskillful movement. The muscles we use depend upon the activity. For example, inarchery we use a limited number of muscles in the upper body to work veryclosely together for a short period of time. In contrast, for wrestling we use mostof the muscles in the body vigorously for a longer period of time. Sometimes weuse different muscles at different phases of an activity, For example, whenthrowing the javelin we use our leg muscles in the run up and our upper body forthe delivery.How do our muscles work?Our muscles work in different ways. There are 3 main types of muscularcontraction.Isotonic and concentric contraction ~ muscle shorten as they contract. The endsof the muscles move closer together. Our biceps works in this way, for examplewhen we do a pull up. Most sporting movement are of this type.Isotonic and eccentric contraction ~ muscles lengthen as they contract undertension. The ends of the muscle move further apart. Our biceps works in this waywhen we lower our body from a pull up position. Plyometric exercise useseccentric contractions.Isometric ~ muscles stay the same length as they contract. There is nomovement, so the ends of the muscles stay the same distance apart. Our shouldermuscles work in this way when we pull in a tug of war. In many sportingmovements the stabilizing muscles hold parts of the body steady as other partmove.
  3. 3. How do our muscles work together?Our muscles can pull by contracting but they cannot push. If one musclecontracts across a joint to bring two bones together, another muscle is needed topull the bones apart gain. Therefore, muscles always work in pairs. We need alarge numbers of pairs to work together in different ways for even simple bodymovements. Our muscles take on different roles depending on the movement weare performing.They work as:Flexors – contracting to bend our jointsExtensors – contracting to straighten our jointsPrime movers – contracting to start a movementAntagonists – relaxing to allow a movement to take placeFixators – contracting to steady arts of the body to give the working muscle afirm baseSynergists – reducing unnecessary movement when a prime mover contracts.They can also fine out movement.How do our muscles work in pair?When a prime mover contracts, the antagonist must relax to allow movement totake place. However, the antagonist muscle will keep some fibers contracting.This is to stop our prime mover moving the joint so hard that the antagonists aredamaged. Sometimes this system fails, for example when sprinters are runningflat out. They may tear their hamstrings and quickly come to a painful stop.Levers in the Body:We move because our skeletal muscles pull hard enough on our bones to makethem move. Our muscles use our bones as levers. Levers have a hinge (or pivot),a load and a force working on them. In our bodies, our joints are the hinges. Thelead is the weight of our body together with anything else in our hands such as aball, racket or dumb-bell. The force is the muscular power we use to move ourbody and the object n our hand.First class lever – the hinge is between the effort and the load (example raisingthe head)Seconds Class Levers – the load is between the koint and the effort (examplestanding on your toes)Third Class Levers – effort is between the load and the joint (example bicep curl)How are our muscle attached to our bones?Our muscles are usually attached to two or more different bones. The musclefiber ends in a strong flexible cord called a tendon. The tendon is fixed deeplyinto the bone and very strongly attached. Tendons vary in shape and size. Someof our muscle are divided up into more than one parts. They may end in two ormore different tendons, which may be fixed to different bones. When ourmuscles make the bones around a joint move, usually one bone stays fixed andthe other moves. The end of the muscle that is attached to the fixed bone is called
  4. 4. the origin. The other end of the muscle is called insertion. It is attached to thebone, which moves as the muscle contracts the insertion moves towards theorigin.Muscle Tone and PostureMuscle tone can be seen when muscle are in a state of slight tension and they areready for action. Regular training tones muscle and helps to create good posture.In addition muscles will hypertrophy (increase in size) and develop betterendurance. Muscle tone develops by regular exercise makes daily tasks such asshopping and gardening easier. It also helps prevent injury as good posturereduced the strain on muscle tendons and ligaments.How does contraction of skeletal muscles work?Skeletal muscles contractions are stimulated by electrical signal transmittedalong motor nerve fibers that have been sent from the central nervous systemCross-bridge are formed between the myosin and actin molecules. The cross-bridge originate on the myosin molecule and attach themselves to the actinmuscle. Then they drag the actin molecule towards the origin of the muscle. It isthe acting molecule that is active and moves the myosin molecules, which arefixed.Muscle contraction and energyEvery time a cross-bridge is formed, energy is required. The energy is providedin the form of a chemical known as Adenosine Triphosphate (AP3).During this break down, energy is released which is used to form on cross-bridge. Duration of the nervous stimulus will determine the duration of themuscle contraction. The strength of the stimulus will determine the force thatthe muscle contraction exerts. There is a limited quantity of ATP in the muscleand muscle contractor continue over a long period of time. ATP has to be rebuiltfrom AP2. The rebuilding of ATP is known as muscle respiration and describes indetail Muscle Respiration.
  5. 5. Muscle FiberThere are two types of muscle fiber slow and fast twitch.They are physiologically different.The amounts of fast twitch or slow twitch fibers in the muscle will determinetheir suitability to certain sporting activities.The amount of each fiber type in our muscles is also determined genetically, thatis , we are born with it.Training will ave little effect on altering the ratio of fast twitch to slow twitchfiber in the muscleThis is why there are people who are ‘natural’ endurance athletes. They havegreater amounts of slow twitch fiber which contracts slowly with little force butdo not tire easily.Other people have greater fast twitch fibers and are naturally’ good at sprintingand throwing. These fibers produce larger forces but tire quickly.How does our body move?Extension – our limbs straighten at a jointFlexion – our limbs bend at a jointAbduction – our limbs are moved away from a line down the muddle of the bodyAdduction – our limbs are moved towards a line down the middle of the bodyRotation – this is a circular movement. Part of the body turns whilst the otherrest (remains still)Circumduction – the end of the bone moves in a circle, for example swingingyour arm in a circle at the shoulderWhat happens to our muscular system as we exercise? There is an increased flow of blood to the working muscle Muscle take up more oxygen from the blood The muscles contract more often and move quickly More of the muscle fibers contract There s a rise in temperature in the muscle Our stores of AP3 and CP in the muscles are used up Waste products such as CO2 and lactic acids build up in the muscle These waste products may lead to tiredness and cramp –DOMS Our store of muscle glucose is used up Endurance is effectedMuscle Changes and SportOur muscles increase in size and strength when we follow a regular strength,training program. This is called hypertrophy. When we do not use our musclesregularly they get smaller and weaker. This is called atrophy.
  6. 6. Muscle Breakdown and RepairThe complicated science of muscle growth, and the danger of muscle breakdownand degradation mean that careful consideration should be given to how wework out, what we eat to recover and what are fitness foals are Understanding what happeningWhen we are working our we are causing muscle breakdown. In the aftermath ofthe workout our body makes repairs to this muscle tissue.Give the Body Repair MaterialsOur body needs carbohydrates and protein in order to cope with musclebreakdown and make the proper repairs. Too much muscle breakdown is bad. Itcan cause a loss of muscle size. Swapping quantity for quality will not result inbigger gains. Make sure the time spend working out is leading to successfulgains.