Support and Movement in Humans and Animals Flashcards
Three types of skeletons
- Exoskeletons
- Endoskeletons
- Hydrostatic skeletons
Necessity of skeletal systems in humans and animals
- Support soft body tissues and maintains body’s shape
- Muscle attachment
- Stores minerals, especially calcium and phosphorus
- Movement
- Protects the internal organs from injury
Hydrostatic skeleton
Consists of fluids within body cavities. The fluid exerts pressure on the walls of the body surrounded by muscles. Soft-bodied organisms such as earthworms maintains a rigid body for muscular action.
Human skeletal system consists of two main parts, which are
- axial skeleton
- appendicular skeleton
Axial skeleton consists of the
- skull
- vertebral column
- ribs and sternum (breastbone)
Human vertebral column consists of
- cervical vertebrae
- thoracic vertebrae
- lumbar vertebrae
- sacrum
- caudal
Characteristics between vertebrae except the atlas vertebra
- Spinous process
- Transverse process
- Centrum (except atlas vertebra)
- Neural canals
Cervical vertebrae
- Short spinous process
- Wide and short transverse process
- Small centrum
- Pair of transverse foramina
Thoracic vertebrae
- Long spinous process
- Long transverse process
- Medium-sized centrum
- Does not have a transverse foramen
Lumbar vertebrae
- Short spinous process
- Short transverse process
- Large centrum
- Does not have a transverse foramen
What is a joint?
Meeting place of two or more bones or between cartilage and bones. Most joints allow bones to move in relation to one another.
Three types of joints
- Immovable joints (sutures on cranium of skull)
- Slightly movable joints (cartilage discs between the first rib and sternum)
- Freely movable joints (hinge joints and ball-and-socket joints)
Ball-and-socket joint
- Allows rotational movement in all directions
- It allows the swinging of arms and legs in circular motion
- Eg :
a) Shoulder joint between the humerus and pectoral girdle
b) Hip joint between femur and pelvic girdle
Hinge joint
- Allows movement of bones in one plane
- The knee joint allows the lower leg to swing back and forth like a hinge on a door
- Hinge joints are also found in the elbows, phalanges of the fingers and toes
Synovial membrane
secretes synovial fluid into the synovial cavity
Capsule
fibrous tissue that encloses the joint and gives protection to the joint
Synovial fluid
acts as a lubricant that reduces friction between the ends of the bones
Cartilage
Acts as a cushion to the joints, it absorbs friction between the ends of bones. The cartilage also protects bones from wearing away.
Ligaments
- At the joints, bones are held together by ligaments
- Consists of a bundle of strong, elastic and tough connective tissues
- Provide support and strength to the joints and allow the bones to bend at the joints
- Elastic –> allow bones to move on the joints and prevent joints from dislocation during movement
Tendons
- Consists of tough, inflexible and unbendable fibres
- Join skeletal muscles to the bones
- When muscles contracts, the pulling force is transferred to the bones through the tendons to produce movement
Skeletal muscles
- Cannot push and stretch but can only contract and pull
- To move bones, muscles work in pairs and act in opposing movements
- Opposing pair of muscles are known as antagonistic muscles
- If one of the muscles contract, the other muscles relaxes and vice versa
- Eg : biceps and triceps
- Muscles that straighten limbs during contraction are known as extensor. Eg : triceps
- Muscles that bends limbs during contraction are known as flexor. Eg : flexor
