Skeletal notes

Anatomy - is the branch of science concerned with describing the bodily structure of humans, animals, and other living organisms. (What we are made of.)

 

Physiology - is the branch of biology that is concerned with how the various body parts function and work together. (How the body works.)

 

Skeletal System

 

- skeleton contains 206 bones

- we are born with more than 300 but some fuse together.

- bone is a hard but flexible tissue

- the skeleton also contains cartilage, a tough, flexible tissue

- cartilage on the ends of bones prevents them from rubbing together

- as a baby your skeleton was almost totally cartilage.

- at two or three months old, calcium gets deposited in the cartilage        and it turns to bone

 

Skeleton is divided into 2 main parts

          1. axial skeleton

                   --The axial skeleton consists of bones that form the axis of                 the body and support and protect the organs of the head,              neck, and trunk.

                   - skull, sternum, rib cage, backbone

                   - backbone is made of smaller bones called vertebrae

                   - 80 bones

         

          2. appendicular skeleton

                   - The appendicular skeleton is composed of bones that                                anchor the appendages to the axial skeleton.

                   - bones of shoulders, pelvis, arms, legs, etc.

                   - 126 bones                                          

Skeleton has several jobs

         

          - support the body

          - covers and protects organs

          - work with muscles to make movement possible

          - by providing a frame to which our muscles and organs attach

          - some bones make blood cells

          - store calcium and phosphorous that the body needs

- when excess is present in the blood, build up will occur within   bones

- when the supply of these minerals within the blood is low, it will be withdrawn from the bones to replenish the supply

 

Bones contain two sections

 

          Compact bone    - made up of living bone cells and minerals

- calcium is what makes bone hard and gives it strength

                                      - calcium in bone comes from our diet

- forms the protective exterior portion of all bones

                  

Spongy bone       - Spongy bone is inside the compact bone and is very porous (full of tiny holes)

                                      - looks like a sponge

                                      - found on the ends of bone

- the spaces are filled with bone marrow where red blood cells are made

- some long bones also contain marrow in the middle

                                      - is strong but lightweight

- will strengthen with resistance exercise (weight lifting)

Bone Marrow

 

Blood cells are produced by the marrow located in some bones.

An average of 2.6 million red blood cells are produced each second by                  the bone marrow to replace those worn out and destroyed by the liver.

 

·Red marrow - produces blood cells and clotting factors

·Found in humerus, femur, sternum, ribs, vertebrae, pelvis

·Produces over 2 million RBC per second

·Red blood cells, platelets and most white blood cells arise in red marrow.

 

·Yellow marrow - stores fat

·Found in many bones

·is found in the hollow interior of the middle portion of long bones.

·In cases of severe blood loss, the body can convert yellow marrow back to red marrow

 

Types of Bone

 

The bones of the body fall into five categories:                                             

          long bones :        Long bones are longer than they are wide and                                               work as levers.  (ex. humerous, femur)

          short bones:        Short bones are short, cube-shaped                                                                (ex. wrists and ankles)

          flat bones:           have broad surfaces for protection of organs

                                      (ex. skull)

          irregular bones: (ex. verterae)

          sesamoid bones: small flat wrapped within tendons                                                                  (ex. kneecap/patella)

 

 

Joints

- bone does not bend so movement can only occur where two bones meet

- the place where two bones meet is called a joint

- bones are connected to each other by ligaments

- ligaments stretch when bones move

- a sprain results when a ligament is stretched too far

- there are three kinds of joints

 

Types of joints

 

          1. fixed       - do not move at all

                             - e.g., the bones of the skull

 

          2. partially moveable   - allow a little movement

                                                - e.g., where the ribs join the breastbone

 

          3. Moveable - allow wide movement

a) hinge joints - allow bones to move backward and forward                           in one direction  - e.g., elbow and knee

 

                   b) ball and socket        - allows movements in all directions

                                                          - e.g., shoulder and pelvis

 

c) pivotal joints   - allows side to side and up and down movements - e.g., neck

 

d) gliding joints - bones slide past each other to allow movements in all directions - e.g., wrist

 

 

 

 

Types of movement at Joints

 

·        Flexion - is the action of bending a joint such that the joint angle decreases.

 

·        Extension - the opposite of flexion (the joint angle increases)

 

·        Abduction - When you move a body part away from the body.

 

·        Adduction - When you move a body part towards your body

 

·        Supination - is rotating your wrist so that the palm is facing upwards

 

·        Pronation - is rotating your wrist so that the palm is facing downward                                          (such as dribbling a basketball)

 

·        Circumduction - combination of flexion, extension, abduction and adduction     all wrapped into one.  Found in shoulder and hip joint.

 

 

Fractures

 

 Fractures  - a break in a bone

                   - there are three main types

 

1. Because a child's bones are much more pliable than adult bone, an incomplete, or 'greenstick,' fracture may occur. A "greenstick fracture" means that one side of the fracture has broken and one side is bent; therefore it is classified as an incomplete break.

2. Simple fracture - the broken bones do not pierce the skin

3. Compound - the bone is sticking through the skin

 

Regrowth of bone:

·Spongy bone forms in first few days

·Blood vessels regrow and spongy bone hardens

·Full healing takes 1-2 months

 

-         Treatment for a broken bone requires preventing the bone from moving.  This is usually done with a cast.

 

Arthritis - a disease that causes inflammation of the joints

          - joints are painful and movement is limited

- usually caused by the cartilage being destroyed so that the bones rub on each other

 

Scoliosis - causes the spine to curve

          - children are usually born with this

          condition but can be caused by disease or

          injury

 

 

 

Anatomical position - standing erect, facing the observer, arms are at                                              the sides with palms facing forward.

Superior - toward the head

Inferior - away from the head

Anterior - the front of the body or body part

Posterior - the back of the body or body part

Medial - toward the midline that divides left and right

Lateral - to the side away from the midline

Proximal - closer to the torso

Distal - farther away from the torso