1.2 structure and function of skeletal system Flashcards
(51 cards)
Five main functions of the skeletal system
- Body movement (most important)
- Framework
- Protection
- Mineral storage
- Production of red blood cells.
Body movement
206 bones in the human body
Bones provide site for muscle attachment and act a levers to create movement
When a muscle contracts, it pulls on the bone which is attached and movement occurs
Framework and protection
The skeleton provides a solid framework for the body and helps battle the forces of gravity
The protective skeletal layer provides protection for many vital organs.
Mineral storage
Bone tissue efficiently stores minerals that are important for health
Calcium, phosphorus, sodium and potassium all contribute to the health and maintenance of bone tissue
Production of red blood cells
Essential production of new red blood cells occurs within the cavity of long bones
Production levels are high during growth years, and diminish as age increases
Such cells are essential for oxygen transportation throughout the body.
Short bones
Short bones are roughly cubical, and have the same width and length
Examples: carpals of the wrist or tarsals of the foot.
Long bones
Long bones are longer than they are wide, and have a hollow shaft containing marrow
Examples: femur, phalanges and humerus.
Sesamoid bones
Sesamoid bones are small bones developed in tendons around some joints
Example: patella
Flat bones
Flat bones provide flat areas for muscle attachment and usually enclose cavities for protection
Example: scapula, ribs, sternum and skull.
Irregular bones
Irregular bones have no regular shape characteristics
Example: vertebrae and bones of the face
Vertebral column
The vertebral column (spine) is crucial for maintaining good posture
Each vertebra has a hollow centre to protect the spinal cord and control conscious body movement.
Vertebrae size increases as they descend (go lower)
Movement between two vertebrae is limited, but overall movement range is considerable
Intervertebral discs separate vertebrae, absorbing shock and enabling bending and twisting
Cervical
Amount of vertebrae: 7
Supports the head. The atlas and axis (top two vertebrae) allow the head to move up, down and side to side.
Thoracic
Amount of vertebrae: 12
Connects the ribcage to the vertebral column
Lumbar
Amount of vertebrae: 5
Supports the weight of the body and provides attachment for large muscles
Sacrum
Amount of vertebrae: 5 fused
Fused part of the pelvis
Coccyx
Amount of vertebrae: 4 fused
Base of the vertebral column (tailbone) and site for muscle attachment
Fibrous joints
Fibrous joints offer no movement (immoveable).
Examples: skull, pelvis, sacrum and sternum.
Cartilaginous joints
Cartilaginous joints are joined by cartilage and allow small movements (slightly moveable).
Examples: vertebrae and where the ribs join the sternum.
Synovial joints
Synovial joints offer a full range of movement (freely moveable) and move freely in at least one direction. Examples: knee or shoulder
Connective tissue
Plays an important role in the function of both the skeletal and muscular systems.
Classed as soft tissue as it does not have the rigidity of bone.
Although it does have the flexibility of soft tissue and the strength that collagen provides.
Cartilage
Cartilage is a smooth, slightly elastic tissue found in various forms within the body:
Hyaline cartilage coats the ends of the bones in synovial joints
Discs of cartilage separate the vertebrae of the spine
The ribs attach to the sternum via cartilage
The hard part of the ear and the tip of the nose are cartilage.
Ligaments
Ligaments cross over joints, joining bone to bone.
Slight elasticity allows small movements from the bones of the joint.
Main function, is to provide stability at the joint, preventing dislocation.
Tendons
Tendons are inelastic and very strong
They allow movement by helping muscles pull through the joint and on the bones.
Synovial joints
Synovial joints a freely moveable and allow movement in one or more directions, and has a joint capsule.
They have:
Cartilage that offers protection and reduce friction.
Ligaments that secure bones in place and allow controlled movement
Enclosure by a joint capsule (a layer of tissue that surrounds the joint)
A synovial membrane (lines the inside of the joint capsule) secretes synovial fluid
