Muscles 2

Explain the effect of increase mRNA concentration

1 proteins needed for repair 2 more transcription of DNA 3 more translation 4 protein synthesis 5 named protein eg actin/ myosin

Suggest a way in which nicotine may act as at neuromuscular junctions to have this effect

1 same shape as ACh 2 causes sodium channels to open 3 binds to receptor sites 4 ref complementary shape of nicotine and receptor 5 post synaptic membrane/ sarcomella 6 stimulates release of ACh 7 inhibits destruction of ACh/ uptake of ACh by motor neurone

State two pieces of evidence that indicate the myofibril is shown in the relaxed state

- wide H zone; - wide I band; - little overlap of filaments - ref to length of sarcomere

suggest two functions of Cerebrospinal fluid (CSF)

-'shock absorber' -removes excess heat/ cools the brain -supplies oxygen -supplies nutrient -removes waste/ CO2 -ref to osmoregulation

Suggest and explain how acetylcholinesterase inhibitors may act to reduce symptoms of Alzherimer's disease

1 ACh at reduced level (in an individual with Alzheimer's) Inhibitor: 2 binds to enzyme 3 competative/ non-competative 4 ACh does not bind to active site 5 ACh not broken down 6 more ACh available for receptor sites/ more action potentials generated

Describe the lever action of the human arm when lifting a weight

1 bones act as levers 2 fulcrum/ pivot 3 muscles supply effort/ force 4 load is weight on arm 5 3rd order lever 6 moveable joint/ synovial joint 7 small movement of biceps cause large movement of the load/ distance multiplier 8 biceps contract 9 tendons 10 insertion/ origin 10 ref raising the forearm 11 antagonistic muslces / triceps relax

Describe the events that occur when muscle contracts. In your answer explain the roles of calcium ions, tropomyosin, troponin, actin and myosin.

1 depolarisation of sarcolemma/ muscle cell membrane 2 depolarisation spreads down transverse system tubules 3 calcium channels in saroplasmic reticulum, open 4 calcium ions released / diffuse out 5 calcium ions bind to troponin 6 tropinin moves tropomyosin 7 exposes myosin binding sites on actin/ thin filaments 8 myosin head binds to binding site on actin/ cross bridges 9 swiveling of myosin 10 ref ATPase/ release ATP + Pi 11 actin/ thin filaments drawn together/ more overlap of thick and thin 12 cross bridges break and reform 13 ATP hydrolysed for release of myosin heads 14 hlyogenolysis/ glycogen hydrolysed to glucose 15 ref glycolysis/ Krebs cycle/ oxidative photophosphorylation 16 production of ATP by mitochondria 17 shortening of sarcomeres/ distance between Z discs decreases 18 reduction in length/ shortening myofibrils/ muscle fibres

State how endorphins may act to reduce pain

1 endorphine attach to opiate receptors 2 ref presynaptic knob/ membrane 3 stops Ca2+ 4 no ACh released 5 no/less binding of ACh on receptors 6 on postsynaptic membrane 7 fewer/ no action potentials/ impulses to pain centre/ brain

Explain how the binding of acetylcholine molecules to proteins in the sarcolemma results in the movement of calcium ions out of the sarcoplasmic reticulum

1 leads to opening of sodium/potassium ion channels 2 entry of sodium ions 3 positive feedback 4 depolarisation of changes in electrical portential of sarcolemma 5 by diffusion/ electrical attraction 6 action potential/ wave of depolarisation/ impulse 7 spreads down fibre 8 T-tubules 9 opening of calcium channels in sarcolemma/ calcium entry into muscle cells 10 opening of calcium channels in SR membranes 11 calcium ions diffuse down concentration gradient 12 calcium ions bind to troponin

Explain the effect of higher rate of oxygen consumption

1 more aerobic respiration 2 so more energy released/ ATP produced 3 energy required for condensation/ anabolic reactions 4 energy required for formation of peptide bonds 5 energy required for formation of extra mRNA

Name the structure that joins the two cerebral hemispheres

corpus callosum

Functions of acetylcholinesterase

breaks down ACh/ enables repolarisation of post synaptic membrane

Explain how the increased concentration of hydrogen ions results in a reduction in the force of contraction of a muscle

calcium ions normally bind to troponin; in presence of hydrogen ions, less binding of calcium ions; less/ no change in shapes/ movement of tropomyosin; no binding of myosin head/ fewer cross bridges; effect of hydrogen ions on tertiary structure of protein; effect on named bond

Name the most common calcium compound in the bone

calcium phosphate

Role of cerebellum

co-ordination of balance; muscle co-ordination; reflex control of posture; control of locomotory actions

Role of the cerebrum

concious thought; co-ordination of valuntary activity; learning; reasoning; intelligence; association of incoming information

Explain why the cerebral cortex is tissue wheras brain is an organ

cortex group of specilised cells/ neurones; performing simialr function; brain is made of more than one different tissues; carrying out more than function

Explain the presence of glycogen cranules in striated muscles

energy supply; supplies glucose for respiration; for generation of ATP

Outline the roles of the structures shown in the ankle joint including cartilage, in the movement of a joint

hyaline cartilage reduces friction; absorbs shock; synovial membrane secretes synovial fluid; oily fluid to lubricate joint; biceps contract to bend arm; triceps contract to extend arm; humerus acts as anchor/ origin of biceps and tricep muscles; readius for insertion of biceps tendon; ulna for insertion of triceps tendon; tendons connect muscles to bones, inelastic; capsular ligamnets connect bones to bones; prevent dislocation

Suggest two consequences of osteoporosis on the lives of people with this condition

increased fracture; reduced mobility; increased pain; Dowager's hump; take named supplements; advised to take aestrogen

Describe the effects of osteoarthritis on load-bearing joints

inflammation; loss of cartilage; calcification of the joint capsule; reduced joint flexibility/ movement difficult; friction causes bone erosion

Explain the advantage of the cerebral cortex being highly folded

larger surface area; idea of more cells/ neurones in given space; idea of more 'processing power'

Functions of acetylcholine

neurotransmitter

Name the type of cell responsible for removing calcium from the bone matrix

osteoclast

Role of medulla oblongata

regulation of autonomic activities; heart rate; blood pressure control; breathing rate; pharyngeal activity eg coughing