SUPPORT, MOVEMENT AND LOCOMOTION
Skeleton system
axial system-skull, vertebral column, ribs and sternum
appendicular system-fore limbs, pectoral girdle, hind limbs, pelvic girdle

Fore arm bones
upper arm-humerus, lower arm-radius and ulna, wrist-carpals, palm-meta carpals, fingers-phalanges

Hind limb bones
upper leg-femur, lower leg-tibia(stout) + fibula (slender), patella-knee cap, instep-tarsals + meta tarsals, toes-phalanges

Functions of the skeleton
support-holds body upright, off ground and maintains shape of body
movement-produced by bones and muscles e.g. raising the arm
protection of delicate internal organs-cranium protects brain
production of blood cell-RBC and WBC produced in red blood marrow of limb bones, ribs, sternum, vertebrae
attachment of muscles-a firm stable structure for placement of muscles

Exoskeleton-external Endoskeleton-internal

Bones
-hard bone-made of calcium phosphate w/ blood vessels running through it
-soft bone-cartilage-reduces friction, absorbs shock, maintains shape

Joints
-point where 2 bones meet or are attached
-1-immovable/fixed2-movable/synovial
-underproduction of synovial fluid >stiffness and inflammation; arthritis
-ligaments torn or over-stretched >dislocation
-replacement joints-used if original damaged/severely arthritic, made from stainless steel (strong+non-corrosive+non-toxic) which may be coated by 'teflon' on working surface

Movable Joints
-ball and socket joint-360 movement(movement in many places)-scapula and humerus, pelvis and femur
-hinge joint-180 movement(movement in one place)-humerus and ulna

Muscles
Involuntary-cardiac(heart)+smooth (organs) muscles, rarely/never fatigue
Voluntary-skeletal muscles

Contraction of muscle
requires-glucose+oxygen for energy (ATP molecules, by respiration, many mitochondria)
-removal of CO₂ and heat (if anaerobic respiration removal of lactic acid or cramp will occur)
satisfied by capillary beds in muscle, but stimulus (nerve impulses) needed from end plates of motor neurons
muscles-effectors, get nerve impulses from brain/spinal cord >contract/relax
If muscle works continuously w/o rest >lactic acid accumulates > fatigue

Antagonistic Muscles
-necessary for controlled movement, found in limbs, work in pairs w/ opp. actions, because muscles only contract
-biceps-flexor triceps-extensor of elbow joint

tendons-attach muscle to bone-inelastic so muscle contraction converted to movement
ligament-elastic, strong- attach bone to bone at a joint-prevents dislocation but allows movement at joints


Transport system in man-circulatory system
Respiration
Excretion
Homeostasis
The Eye
Nervous System
Chemical Control of Plant Growth
The Use and Abuse of Drugs
Diversity of Organisms
Nutrient cycles and Ecology
Parasitism
The Human Impact on the Environment
Reproduction in plants
Sexual reproduction in animals
Genetics
Cell Structure and Organisation
Enzymes
Nutrition
Transport in Plants

Back to 'O' level notes index

Back to notes index