2.1 Support and Locomotion in
Humans and Animals Importance of support and locomotion
◦ Search for food
◦ Provide protection by escaping from enemies
or avoiding danger
◦ Search for more conducive living environment
◦ Find mates for reproduction
◦ Avoid overcrowding which enables the
offspring to move to another place
2.1 Support and Locomotion in
Humans and Animals (cont’d)
Human skeletal system
◦ Consist of two main part; axial skeleton and
appendicular skeleton
Human
skeleton
Parts
Axial skeleton 1. Skull
2. Vertebral column
(the backbone)
3. Ribcage
Cranium, bones of the face, jaw
Cervical vertebrae, thoracic vertebrae,
lumbar vertebrae, sacrum, coccyx
Sternum and ribs
Appendicular
skeleton
1. Pectoral girdle
2. Arm (forelimbs)
3. Pelvic girdle
4. Leg (hind limbs)
Scapula and clavicle
Humerus, ulna, radius, carpals,
metacarpals, phalanges
Ischium, pubis, ischium
Femur, tibia, fibula, tarsals, metatarsals.
phalanges
2.1 Support and Locomotion in
Humans and Animals (cont’d) Skull
◦ Cranium – enclose and
protect the brain
◦ Facial bones and jaw
Protect the eyes and ears
Upper jaw is fixed
◦ Skull is joined to the
vertebral column at the base
of cranium
2.1 Support and Locomotion in
Humans and Animals (cont’d)
Rib
◦ Twelve pairs of ribs
Articulate with thoracic cavity
dorsally, and sternum ventrally
◦ Sternum is the front part
2.1 Support and Locomotion in
Humans and Animals (cont’d) Vertebral column
◦ Consists of 33 vertebrae, joined but separated
by discs of cartilage
◦ Five types of vertebrae
1. Cervical vertebrae (7)
2. Thoracic vertebrae (12)
3. Lumbar vertebrae (5)
4. Sacral vertebrae (5)
5. Coccyx
2.1 Support and Locomotion in
Humans and Animals (cont’d)
Centrum
Gives support
Neural arch
Forms neural
canal
Neural spine
Muscle
attachment
Neural canal
Protects spinal
cord
2.1 Support and Locomotion in
Humans and Animals (cont’d) Support head and
neck
Sentrum is short
and thick
Large and thick
sentrum
2.1 Support and Locomotion in
Humans and Animals (cont’d) Appendicular skeleton
◦ Consists of
1. Pectoral girdles and forelimbs (arms)
2. Pelvic girdle and hind limbs (legs)
2.1 Support and Locomotion in
Humans and Animals (cont’d) Joints
◦ Place where two bones
meet
◦ Bones are held together by
ligaments
◦ Sinovial joints – joints
that contains a cavity filled
with fluid
◦ End of bones are covered
with cartilage.
2.1 Support and Locomotion in
Humans and Animals (cont’d) Joints
◦ Various types of joints
1. Hinge joint Allow movement in one plane
2. Ball-and-socket joint Allow movement in all directions
2.1 Support and Locomotion in
Humans and Animals (cont’d) Movement in a limb
◦ Skeletal muscles are attached to bones by tendons.
◦ Movements of cause by antagonistic movement of muscles: One muscles is contracted, another is relaxed
2.1 Support and Locomotion in
Humans and Animals (cont’d) Structure of a muscle
◦ Muscle fibre – single, long cylindrical cell that contains many nuclei
◦ Myofibrils – smaller units that made up muscle fiber
◦ Interaction of actin and myosin will cause muscle contraction
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of earthworm
◦ Earthworms have a hydrostatic skeleton (the force of contraction is applied to a coelum(fluid filled chamber).
◦ Coelom is surrounded by two antagonistic muscle circular muscles – surround the chamber
longitudinal muscles – extend from one end to the other.
◦ Thinner and longer: When circular muscle contract and the longitudinal muscle relax. (and vice verca)
◦ The muscles contract rhythmically to produce peristaltic waves which begins at the front and move towards the end of the body.
◦ Earthworm has chaetae (bristles) which anchor parts of the body to the ground so that other parts can be pulled towards it.
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of grasshopper
◦ The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton.
◦ Flexor muscles bend a joint.
◦ Extensor muscles straighten it.
◦ The rear legs of a grasshopper are long and muscular and is adapted for hopping.
◦ Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump.
◦ Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of grasshopper
◦ The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton.
◦ Flexor muscles bend a joint.
◦ Extensor muscles straighten it.
◦ The rear legs of a grasshopper are long and muscular and is adapted for hopping.
◦ Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump.
◦ Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of fish
◦ Fish has streamlined body shape
◦ Scales that overlap one another, with free ends
pointing backwards to reduce friction
◦ Fish have W-shaped muscles called myotome
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of fish
◦ Fish move forward
from the
contraction and
relaxation
(antagonistic) of
myotome on either
side of the body
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of fish
◦ Function of fins in fish – balance the body
◦ Pectoral fins – for steering
◦ Pelvic fins – for balance, to prevent diving and
rolling
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of bird
◦ Bird can fly either by flapping their wings or
gliding
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of bird
◦ When wings move down Pectoralis major contracts
Wings are pulled down
◦ When wings move up
Pectoralis minor contracts
2.1 Support and Locomotion in
Humans and Animals (cont’d) Locomotion of bird
◦ During gliding, wings
are spread – act as
aerofoil
◦ Bernoulli principle –
provide upward
thrust
2.3 Support Systems in Plants
Support in plants is necessary to:
◦ Stay upright
◦ Obtain sufficient sunlight
◦ Bear the weight the plant
◦ Provide strength to withstand wind
ressistance
2.3 Support Systems in Plants
(cont’d)
Plants
Aquatic
Submerged Floating
Terrestrial
Herbaceous Woody
2.3 Support Systems in Plants
(cont’d) Submerged plants
◦ Hydrilla sp.
◦ Have thin, narrow and
flexible leaves – provide
little ressistance
◦ Air sacs inside the
leaves and stems - keep
the plant floating close
to the surface to obtain
maximum sunlight.
2.3 Support Systems in Plants
(cont’d)
Floating plants
◦ Lotus plant
◦ Have broad leaves that are firm but flexible
enough to resist tearing by wave action.
◦ Aerenchyma tissues (spongy tissues with large
air spaces between the cells) in the stems and
leaves provide buoyancy so that the plants can
float on the surface of the water
2.3 Support Systems in Plants
(cont’d) Herbaceous plant
◦ Support provided by the turgidity of the parenchyma and collenchyma cells.
◦ Turgor pressure of the fluid content in the central vacuole pushes the cell membrane and the cell contents against the cell wall, creating support for the stem, root and leaves.
◦ The thickening of the cell walls with cellulose and pectin in collenchyma cells provide additional mechanical strength
2.3 Support Systems in Plants
(cont’d) Woody plants
◦ Support provided through tissue
modification
◦ Xylem tissues
Strenghtened by lignin
Lignin – tough, not elastic and nor permeable
to water
◦ Parenchyma tissues
Store starch, sugars and water
It become turgid – give support
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