fit for life - skeletal system Flashcards
What is the skeletal system made up of?
The skeletal system is made up of joints and bones.
What are bones?
Bones are living organs that help us stand and move.
How many bones do you have?
You are normally born with 300 but 94 of them fuse as you get older leaving you with 206.
What are the 5 main functions of the skeletal system?
Body movement, support, protection, mineral storage and the production of red blood cells.
Body function?
There are over 200 bones in the body which provide sites for muscle attachment. When muscles contract they move the bones they are attached to. Muscles are attached to bones by tendons.
Support?
The skeleton supports the body by keeping us upright. Weaknesses in muscles or bones can lead to poor posture.
Protection?
Bones protect vital organs such as the heart, lungs,
kidneys and brain.
Mineral storage?
Bones store minerals that are essential for good health, such as calcium and sodium. Calcium is important for good bone health and muscle contractions.
Production of red blood cells?
Red blood cell production occurs in the cavity of long bones. RBC is important in the transportation of oxygen around the body. The oxygen attaches to haemoglobin in the red blood cells to be transported from the lungs. As we get older the production of red blood cells slows down.
Axial skeleton
Consists of the skull, vertebral column, ribs and sternum (thorax). It forms the major axis of the body as it is supportive and rigid and also protects many vital organs.
Appendicular skeleton
Includes the appendages (limbs) of the body and is used mainly for movement. It’s joined to the axial skeleton by the pelvic and pectoral girdles.
What are the types of bones?
Short, long, flat, irregular, sesamoid.
Short bone
Cube-shaped, with the same width and length. They are designed for strength and weight-bearing. For example; carpals and tarsals.
Long bone
Longer than they are wide. They have a hollow shaft containing marrow. The primary function is to act as levers and therefore essential for movement. For example; tibia, fibula, femur, phalanges.
Flat bone
Have large flat areas for muscles to attach and usually protect vital organs. For example; scapula, ribs, sternum.
Irregular bone
No regular shape or characteristics. They have a variety of functions which include protection. For example; the pelvis and vertebrae.
Sesamoid bone
Bones that are small, surrounded by tendons and located around a joint. Sesamoid bones have a specialised function: They ease joint movement and resist friction and compression. For example; the patella.
Factors affecting bone growth
Injury, diet, exercise, disease.
Injury
Injuries such as fractures can affect bone growth.
Diet
Bones need calcium and phosphorous
Excercise
Weight-bearing exercise pulls on bones and
increases bone density.
Disease
Osteopenia, osteoporosis, osteoarthritis.
How are joints formed?
Joints are formed when 2 or more bones articulate.
How is movement created?
The tendons of muscles usually cross joints and attach to bones to create movement.
What are the 3 types of joints?
Fibrous, Cartilaginous and synovial.
Fibrous
No movement. E.g. the skull
Cartilaginous
Slight movement E.g. Between the ribs
Synovial
Freely moveable.
What are the 6 synovial joints?
Hinge, Ball and socket, gliding, pivot, condyloid and saddle.
Hinge
The hinge joint allows only back-and-forth
movement, such as bending and straightening.
E.g. Knee
Ball and socket
The ball and socket joint permits side-to-
side, back-and-forth and rotational movement.
E.g. Hip
Gliding
The gliding joint occurs where two bones
with flat surfaces slide over each other,
with their movement restricted by ligaments.
E.g. Carpals/tarsals
Pivot
The pivot joint allows rotation only.
E.g. Neck
Saddle
Resembles a saddle and is similar to a condyloid joint, however, allows more movement.
E.g. Thumb
Condyloid
In condyloid joints, one bone surface is concave, the other is convex.
E.g. Wrist
Superior
Closer to the head than another part
Inferior
Closer to the feet than another part.
Anterior
Towards the front of the body.
Posterior
Towards the back of the body.
Medial
Towards the imaginary midline of the body
