Topic 7

Frage	Antworten
What is the purpose of the articular cartilage?	It protects bones within joints. It is a shock absorber. Creates less friction between bones.
What is the purpose of a tendon?	Attaches muscle to bone, causing movement.
What is the purpose of a ligament?	Holds bone to bone and restricts movement.
Define origin and insertion	The origin is the fixed attachment where the muscle originates. The insertion is the part of the body that moves with contraction. E.g. the knee is the insertion when you bend it and the hip is the origin.
What is inside a muscle cell?	Cytoplasm, mitochondria, myofibrils.
What are myofibrils made up of?	Sacromeres which are contractile elements
What do sarcomeres contain?	Actin (thin) and myosin (thick)
What are the three types of muscle?	Smooth (involuntary contraction of lungs) Cardiac (striated, involuntary contraction) Skeletal (striates, voluntary contraction, multinucleate)
Describe a Skeletal Muscles characteristics	Has its own nerve to stimulate contraction. Has its own artery providing oxygenated blood. Has its own vein to remove waste products.
Describe the sliding filament theory	When a muscle contracts, the sarcomeres become smaller but the filaments do not change in length. Instead, they slide past each other; actin slides between myosin filaments and the zone of overlap becomes larger.
What is the effect of lactate build up?	Lactate forms lactic acid in solution. This means pH of cells falls and inhibits enzyme activity of enzymes that catalyse Glycolysis?
Why does lactic acid inhibit enzyme activity?	Hydrogen ions from lactic acid accumulate in the cytoplasm and neutralize negatively charged groups in enzyme active site. The attraction between enzyme and substrate groups will be affected, no binding happens.
What happens to lactate after a period of anaerobic respiration?	Most is converted back to pyruvate which is the oxidised directly to CO2 and water via the Krebs cycle, synthesizes ATP.
What is Oxygen Debt or Post-Exercise Oxygen Consumption?	The excess oxygen requirement after exercise
What is Oxygen Debts purpose?	Needed for the removal of lactate
Why is active recovery after exercise important?	To maintain rapid blood flow to supply muscles with oxygen for lactate removal
What is the immediate regeneration of ATP achieved by at the start of exercise?	Phosphocreatine
What is the efficiency of anaerobic respiration and how many ATP produced per glucose?	2%. 2 ATP per mol. glucose
What is aerobic capacity?	The ability to take in, transport and use oxygen
What is aerobic capacity measured in?	Volume of oxygen consumed, VO2
What is VO2 Max?	The maximal amount of oxygen that the body can utilise during a period of maximal aerobic exercise
What factors can affect VO2 max?	Oxygen uptake, genetics, age, sex, body composition
What is Cardiac Output?	The volume of blood pumped by the heart per minute
What is cardiac output dependent on?	Volume of blood ejected from left ventricle (stroke volume) and heart rate
What is the calculation for Cardiac Output?	Cardiac Output = stroke volume x heart rate
What is venous return?	Blood returning to the heart
Will a larger heart have a lower or higher resting heart rate and stroke volume?	Lower heart rate and an increased stroke volume circulating the same amount of blood aeround the body
What is heart muscle described as?	Myogenic, as it doesn't need input from the nervous system
What is heart mscle contraction caused by?	Changes in cells electrical charge. Changes in polarity spread across the heart causing cells contraction
How much energy is released in the hydrolysis of ATP?	30.6 kj mol-1
In what 2 ways in the energy for ATP production synthesises?	Substrate level phosphorylation and Chemiosmosis
Why is ATP useful energy storage molecule?	- it can not pass out of a cell - packages energy into small, useful amounts - it is easily hydrolised
What happens to lactate after aerobic respiration takes place again?	Lactate converts to pyruvate as it is oxidised. It is broken down in the liver to release energy (glycogen) for muscles.

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