antagonists/agonists/isometric/isotonic/fixator muscles/origins/insertions

an antagonist is where the muscle lengthens/relaxes in the event of a muscular contraction, for example the upwards phase of a leg curl, the bicep femoris is relaxed.

this is where the agonist comes in- this is where the  muscle shortens in the event of a muscular contraction for example the leg curl the rectus femoris shortens, making it the agonist

the rectus femoris and biceps femoris work accordingly in the upwards phase of the leg curl, one being the agonist and one being the antagonist.

the fixator muscles are the muscles which hold the muscles controlling the movement together by contracting. for example in the upwards phase of a bicep curl whereby the bicep femoris is flexing, the latissimus dorsi, trapezius, and pectorals major contracting, holding the movement together.

the origin of a muscle is the part of the muscle which remains fixed during contraction-it doesn't move.usually at the top of the muscle. the insertion of a muscle is the part which tends to move towards the origin during contraction. usually at the bottom of the muscle

an isometric contraction is where there is no joint movement during a contraction. for example a rugby scrum the shoulder and back muscles (posterior and anterior deltoids, and trapezuis') contract isometrically and the muscle do not shorten or lengthen when contracting.

in an isotonic contraction there are two parts; concentric and exentric. concentric is where the muscle shortens under contraction, for example the upwards phase of the bicep curl in the biceps brachii. exentric is where the muscle lengthens under contraction, for example the downwards phase of the bicep curl, the biceps brachii lengthens through extension at the elbow.

10 MARK ANSWER FOR 'DESCRIBE THE CHARACTERISTICS OF CORONARY HEART DISEASE. EXPLAIN HOW AN ACTIVE HEALTHY LIFESTYLE CAN HELP PREVENT CORONARY HEART DISEASE.' 

coronary heart disease has 4 factors; atherosclerosis, angina, artereosclerosis, and a heart attack/cardiac arrest, which all have different characteristics. an active healthy lifestyle can help to prevent these in a variety of ways. through good diet and regular physical activity as well as leading to a stress free life. 

      

atherosclerosis is where the lumen of a coronary artery narrows due to a deposit of cholesterol/blood lipids/triglycerides. this means that more blood pressure is required to maintain blood flow. it can result in restricted blood flow to the heart and even blood clots. It can also result in hypertension which is where blood pressure values rise to 200/120 mm Hg which causes added strain to the heart. a healthy active lifestyle can prevent this by having a balanced diet; with reduced fats and carbohydrates, and increased proteins, vitamins, minerals and fibres.

       

                angina can occur as a result of atherosclerosis. it is where there is a restricted blood flow to the heart and certain areas of the heart muscle wall are deprived of blood. this can cause severe chest pain at any time however it is most noticeable during exercise when heart rate is increased. an active healthy lifestyle can help prevent coronary heart disease and angina. by participating in the daily guidelined exercise times (30 mins 5 times a week). the heart muscle walls will hypertrophy (increase in size) and will have a better capacity to cope with high blood pressure.

                   a heart attack/cardiac arrest is where the heart is starved of oxygen due to a restricted blood flow. Angina can sometimes be a sign of a heart attack occurring in the near future.a heart attack can also be a result of atherosclerosis and artereosclerosis (where arterial walls restrict blood flow due to hardening). it is an intense chest pain an can have effects such as; long term heart tissue damage and even death. a healthy balanced diet, regular participation in physical activity and leading to a stress free life. when stressed blood pressure rises which can enhance the effects of angina, artereosclerosis, atherosclerosis, which are ultimately the main causes of a cardiac arrest/a heart attack.

        conclusively CHD has a range of characteristics which range in effects on the heart. however a balanced active and healthy lifestyle can help to prevent these effects with a stres free life, regular physical activity, and a healthy balanced diet.