Module 6 review 1. Describe smooth, skeletal and cardiac muscle. Also tell where you would find these in the body. Smooth around internal organs (involuntary control) (one nucleus per cell) Skeletal pulls on bones (voluntary control) (multi-nucleated) Cardiac heart (involuntary control) (are branched and have one nucleus per cell) Smooth not striated / Skeletal and cardiac are striated 2. Differentiate between actin and myosin Actin thin filament Myosin thick filament with cross - bridges 3. Describe the sliding filament model of muscle contraction. Myosin forms cross-bridges on actin and slides actin towards the center pulling the sarcomere towards the center shortening it Muscle contraction relies on the action between two types of myofilaments actin and myosin Actin is a pair of protein strands woven together that resembles a string of beads The myosin myofilament consists of protein molecules wound together The mysoin filaments have heads that stick Contraction
1.The myosin head is attached to the actin filament 2.The myosin head then flexes, moving the actin filament 3.The myosin head releases and unflexes, powered by ATP 4.The myosin head reattaches to the actin filament in a new location The actin slides past the myosin, and this movement is therefore known as the sliding filament model The actin is anchored to a position within the striated muscle known as a Z line When a muscle contracts, the actin moves and along with it, the Z line also moves These Z lines are attached to the membranes of other cells in the tissue, causing the contraction of the entire muscle Calcium Ions and Contraction Initially, when a muscle is relaxed, the myosin heads are ready to bind to actin but they cannot bind This is because a protein known as tropomyosin prevents their binding The tropomyosin can be moved by another protein known as troponin, which is activated when calcium is bonded to it Therefore, when muscles contract, Ca 2+ ions diffuse into the myofibrils and attaches to troponin, allowing the myosin heads to bind with actin The release of calcium is due to a a nerve impulse. Thus muscles can t contract without Calcium 4. Why are ATP and calcium required for muscle contraction? Ca required to cause the actin to change shape exposing active sites and ATP required for the sliding motion/deattachemt ATP provides energy from muscles However, the method through which this ATP is produced can vary ATP RELEASE ENERGY THROUGH THE CONVERSION OF ATP INTO ADP AND THE RELEASE OF A PHOSPHATE.
5. What is creatine-phosphate and how does it aid in muscle contraction/relaxation It is a pathway to reform ATP during muscle contraction
6. Know 3 injuries related to athletics baseball finger blocker s arm charley horse compactment syndrome pitcher s arm pulled groin pulled hamstrings rider s bones rotator cuff injury shin splints tennis elbow tennis leg What is a Muscle Strain? A muscle strain is damage caused by over-stretching of muscle tissue. In football, this is thought to occur most frequently when movements such as sprinting, stretching for the ball or kicking the ball are carried out in an unco-ordinated manner. The muscle tissue becomes overloaded and reaches a breaking point where a tear or partial tear occurs. The player will experience pain that will persist if he or she attempts to stretch or contract the muscle. How are Muscle Injuries Treated? The immediate treatment consists of the 'PRICE' protocol: Protection of the injured part from further damage, Rest, Ice, Compression and Elevation. The aim of this protocol is to reduce bleeding within the muscle tissue. Ice therapy in the form of ice pack applications should be continued for the first three days after the injury (never apply ice directly to the skin). The rehabilitation after this period involves gradually stretching the muscle to elongate the scar tissue and progressively increasing the muscle strength. Once this has been achieved, the player can begin sport-specific exercises, such as running, jumping and kicking. To reduce the risk of re-injury, this should be done under the supervision of a chartered physiotherapist. 7. The strength of contraction of a muscle depends on? number of fibres stimulated. 8. What is oxygen debt? Oxygen debt is the oxygen that needs to be replaced or paid back to the various systems in the body, such as the lungs, hemoglobin and myoglobin (found in the muscles of the body) and body fluids. This repayment of oxygen would catabolize the lactic acid formed in the muscles back to carbon dioxide and water.
When the energy required by the body exceeds the oxygen supply available to the body, the muscles get their oxygen from the breakdown of the ATP (Adenosine Triphosphate) in the body. When this is also consumed, then additional ATP is produced by glycolisis without the use of oxygen (as it normally happens when ATP is produced in the body) and this process is called anaerobic glycolisis. This in turn, converts the pyruvic acid into lactic acid, which is then transported to the liver where it is broken into its two basic components, glucose and glycogen. Hence, the muscles get their energy supply when needed. When a person goes through this process, he/she normally becomes short of breath, since all of the oxygen is consumed by the muscle cells as a result of the strenuous exercise involved, and the rest of the body feels the need to supply more oxygen faster. This is when the person starts gasping for breath, which will be fast and shallow. As soon as the demanding type of exercise has ceased, the body reverses the processes in order to refill the oxygen that it has been depleted from different parts of the body. 9. Know the following diagram 10. Understand what happens to the sacromere during muscle contraction?