Run For Your Life

Question 1

Describe how joints work.

Answer 1

Muscle pairs are antagonistic. Muscles causing extension are extensors and flexors reverse the change.

Tendons join muscle to bone.
Ligaments join bone to bone and are strong and flexible.
Cartilage absorbs synovial fluid and shock.

Question 2

What makes up muscle cells?

Answer 2

Muscles are made up of muscle fibre cells. Muscle fibre cells are multinucleate. These are bound by connective tissues. These make up muscle cells. Muscle cells contain organelles and microfibrils. Microfibrils are made up of sarcomeres.

Question 3

Describe sliding filament theory.

Answer 3

Nerve impulses at a neuromuscular junction release Ca2+ ions from the sarcoplasmic reticulum. These diffuse through the sarcomere. Ca2+ ions attach to troponin on the actin causing tropomyosin to shift position and expose myosin binding sites. Myosin heads bind with binding sites and form cross bridges. This releases ADP and Pi. Myosin changes shape and the myosin head moves forward. Actin moves over the myosin.
ATP binds to myosin causing the head to detach. ATPase hydrolyses ATP to ADP and Pi changing the shape of the myosin head and returning the myosin head to it’s previous position.

Question 4

Describe glycolysis.

Answer 4

Occurs in the cytoplasm. 2x ATP phosphorylate glucose, producing 2x ADP. Glucose splits to form 2x triose phosphate (3C). This is oxidised by 2x NAD to form 2x pyruvate. Phosphate phosphorylates 4x ADP to 4x ATP. There is a net gain of 2x ATP.

Question 5

Describe the link reaction.

Answer 5

Pyruvate is actively transported to the mitochondria. Decarboxylation and dehydrogenation occur, producing 2x 2C molecules. Hydrogen forms reduced NAD. CoenzymeA is added to the 2C compound, along with fatty acids, producing AcetylCoA.

Question 6

Describe the Krebs cycle.

Answer 6

Occurs in the matrix of the mitrochrondia. AcetylCoA combined with a 4C sugar to produce 6C citric acid. Citric acid is oxidised, 3x NAD and 1x FAD are reduced. This forms a 5C sugar. 2x CO2 is removed, producing a 4C sugar. ADP is phosphorylated producing 1x ATP.

Question 7

Describe the electron transport chain.

Answer 7

H+ and e- from glycolysis reduce and oxidise NAD in a cycle. The e- is used in the electron transport chain. The cristae of the mitochondria make ATP in oxidative phosphorylation. FADH produces 1.5x ATP, NADH produces 2.5x ATP. Electrons pass on via redox reactions. Chemiosmosis occurs due to a high concentration of H+ ions. The H+ ions diffuse, allowing ATPase to synthesisr ATP. e-, H+ and oxygen form water.
Loss of oxygen stops transport chain.

Question 8

Describe anaerobic respiration.

Answer 8

In glycolysis, pyruvate is oxidised to produce lactate in animals and ethanol in plants and microorganisms.

Question 9

Describe the use of creatine phosphate.

Answer 9

Stored in muscles and hydrolysed quickly to produce ATP.

Question 10

Define aerobic capacity.

Answer 10

Ability to take in, transport and use oxygen.

Question 11

Describe VO2.

Answer 11

VO2(max) is the maximum amount of oxygen consumption. Measured in ml min-1 kg-1.

Question 12

How is adequate oxygen supply maintained?

Answer 12

Increased cardiac output, faster and deeper breathing rate.

Question 13

Define cardiac output.

Answer 13

Volume of blood pumped by the heart in one minute.

Question 14

What is the calculation for cardiac output?

Answer 14

Cardiac output = stroke volume X heart rate.

Question 15

Define stroke volume.

Answer 15

The volume of blood pumped out of the left ventricle.

During exercise, more blood returns in venous return.

Question 16

Describe how heart rate is controlled.

Answer 16

Heart muscle is myogenic and thus can contract without external nervous stimulation.

Depolarisation starts at the sinoatrial node in the right atrial wall. This generates an electrical impulses which contracts the atria. This impulse delays, allowing the ventricles to fill, before reaching the atrioventricular node. The impulse continues to the Purkinje fibres and then the bundle of His. The ventricles are depolarised and contract.

Question 17

Define tachycardia.

Answer 17

Abnormally fast heartbeat. Little blood is pumped, no time to fill.

Question 18

How is tachycardia treated?

Answer 18

Relaxation therapy.

Beta blockers.

Question 19

Define bradycardia.

Answer 19

Abnormally slow heartbeat. May be caused by good aerobic fitness. Affected by beta blockers and tranquilisers.

Question 20

How does the nervous system control the heart?

Answer 20

The autonomic system consists of the accelerator (sympathetic) and the vagus nerve (parasympathetic). The accelerator increases heart rate. Adrenaline dilates arteries, increasing blood flow. The vagus nerve decreases heart rate.
An excessive rise in blood pressure is avoided by negative feedback.

Question 21

Define tidal volume.

Answer 21

In and out in each breath.

Question 22

What is the calculation for minute ventilation?

Answer 22

Minute ventilation = tidal volume x number of breaths.

Question 23

Describe inhalation.

Answer 23

Intercostal and diaphragm muscles contract. Volume increases, ribs move up, diaphragm moves down, low pressure.

Question 24

Describe exhalation.

Answer 24

Stretch receptors are stimulated and send inhibitory impulses. Causes elastic recoil. Internal intercostal muscles contract. Volume decreases, ribs move down, diaphragm moves up, high pressure.

Question 25

How is breathing rate controlled?

Answer 25

Carbon dioxide dissolves in blood, forming carbonic acid. Dissociates into H+ and HCO3-, lowering pH.
Chemoreceptors in the medulla oblongata detect a change in H+ concentration. Impulses stimulate muscles.

Question 26

Describe the impact the exercise has on breathing rate.

Answer 26

Impulses from motor cortex increase ventilation. Impulses from stretch receptors.

Question 27

Describe slow twitch muscle fibres.

Answer 27

Many mitochondria, myoglobin (red), capillaries. Fatigue-resistant.

Question 28

Describe fast twitch muscle fibres.

Answer 28

White, many sarcoplasmic reticulum, high glycogen content. Fatigues quickly.

Question 29

Define homeostasis.

Answer 29

Maintenance of a stable internal environment regardless of external influences.

Question 30

Describe how homeostasis is maintained.

Answer 30

Receptors detect a deviation and control effectors in negative feedback.

Question 31

What changes are made when the thermoregulatory centre detects the body is cold?

Answer 31

Arteries constrict. Hairs stand on end. Goosebumps. Shivering. Raised metabolic rate.

Question 32

What changes are made when the thermoregulatory centre detects the body is hot?

Answer 32

Stimulated sweat glands. Dilated arteries.

Question 33

Describe the effect of over-exercising.

Answer 33

Suppresses the immune system. Damage to joints, cartilage damage, tendonitis, bursitis (fluid sacs).

Question 34

How are the effects of over-exercising dealt with?

Answer 34

Arthroscopy, keyhole surgery.

Prosthetics.

Question 35

Describe the effect of peptide hormones.

Answer 35

Bind to receptors which activate a second messenger, causing chemical change.

Question 36

Describe the effect of steroid hormones.

Answer 36

Bind to a receptor, function as a transcription factor, turning on/off enzyme synthesis.

Question 37

Describe the effect of EPO.

Answer 37

Peptide hormone, produced by kidneys, forms new blood cells.

Question 38

Describe the effect of testosterone.

Answer 38

Steroid hormone, binds to androgen receptors, modifying gene expression, increasing muscle size and strength.

Question 39

Describe the effect of creatine.

Answer 39

Not banned. Increases levels of creatine phosphate which produces ATP, improving performance levels.