EXS2 Cheat Sheet (DRAFT) by Shr_uti_21_D

1. Shape and Size. The bones play an important part in determ­ining your height and build. Skeleton bone size can affect your perfor­mance in different sports.

3. Protec­tion. Many of our body parts and internal organs are protected by skeletons.

5. Blood Cell Produc­tion. Red and white blood cells are made in the bones.

The body is made up of 206 bones and can be divided into two distinct sections.

Append­icular skeleton - provides support for the appendages (external body parts). Includes limb bones and girdles which connect to the axial skeleton.

Bone is a replac­ement tissue - meaning it uses a model tissue to lay down its mineral matrix. During foetal develo­pment, a framework is laid done that determines where bones will form. As the child grows and develops, bone forms cartil­aginous matrix. By foetus birth, most of the cartilage has been replaced.

Ossifi­cation is the process by which bone is formed from cartilage. The cartilage cells die off and are calcified to produced bone. Foetuses are initially formed from elastic tissue called cartilage (except for clavicle and parts of the cranium). As a baby grows, the cartilage becomes bone and hardens. This is part of the process of bone growth

Intram­emb­ranous Ossifi­cation bone develops directly from mesenchyme (conne­ctive tissue found in developing embryo). Compact and spongy bone develops directly from sheets of mesenc­hymal (undif­fer­ent­iated) connective tissue in the embryo (most flat face bones, cranial bones and clavicles) formed via this pathway. Intram­emb­ranous ossifi­cation begins during foetal develo­pment, and continues into adoles­cence. At birth the skull and clavicles not fully ossified nor are skull sutures closed allowing the skull and shoulders to deform during passage through the birth canal

There are two types of bone tissue.

Cancellous (Spongy Tissue) Honeyc­ombed appear­ance. Strong and light. Found in places where extra strength is needed. Found mainly at the end of bones where they flare out to form joints.

Long shaft containing yellow bone marrow. Respon­sible for a lot of movement and often act as levers. Long bones also contain red bone marrow for producing blood cells.

The end or the head of the bone is called the epiphysis. It is made up mainly of spongy bone which is full of tiny cavities. The shaft of the bone is called the diaphysis. It is hollow and made up of hard, dense compact bone. Periosteum is the membrane of the bones and is composed of connective tissue and osteob­lasts.

Flat bones perform a variety of functions including protection and muscle attach­ment.

Examples: cranium, sternum

Very light and strong and are small and squat in shape.

Examples: carpals, tarsals

Specif­ically shaped to perform a particular function.

Examples: patella, vertebrae

A small bone that has developed in tendons around some joints of which the patella is the largest one.

Blast Forming

Cyte Cell

Hyaline Cartilage White, smooth, slipper surface found on the end of bones. Protects the end of bones, reduces friction in the joints.

Marrow Cavity Found in diaphysis, contains yellow bone marrow and consists of blood vessels, fat cells and immature white blood cells.

The vertebral column is made up of 33 irregu­larly shaped bones. Between each vertebrae there is a pad of cartilage which allows movement and prevents the bones from grinding together. Cartilage is a type of connective tissue (softer than bone) that helps cushion joints and holds the bones together. The vertebrae protect the spinal cord (important nerve that runs through the centre of each vertebra). There are 5 sections of the vertebral column.

Thoracic vertebrae (T1-T12) - Protective shield for heart and lungs

Sacrum (5 fused bones) - Fuses to Pelvis and helps with weight distri­bution

Zygomatic bone

Orbit (eye socket)

Genu

Mandible

Axis

Humerus

Ulna

Tibia

Carpals, metaca­rpals

Phalanges

Calcaneus

Pelvic girdle: illium, ischium, pubis (joint: acetab­ulum)

Joints are places where two or more bones meet. They are respon­sible for a huge range of motion and there are 3 types of joints.

Cartil­aginous Joints Bones are separated by cushion of cartilage. Joints between the vertebrae are cartil­agi­nous. The bones can move a little bit but ligaments stop them from moving too far.

Ball and Socket Joint: rounded end of one bone fits inside a cup-shaped ending on another bone. Allows movements in all directions and rotation. Are the most mobile joints in body. Examples: shoulder joint and hip joint.

Saddle joint: ends of two bones fit together in a special way allowing forward, backward, left and right but no rotation. Example: only one, in thumbs.

Condyloid joints: oval-s­haped bone which fits into a corres­pon­dingly shaped bone end. Allow forwards, backwards, left and right movement but no rotation. Examples: joints between phalanges and metaca­rpals.

Minerals and calcium are important in your diet and specif­ically for bone strength. By the age of 35 bone tissue begins to be broken down more quickly than it is replaced. Osteop­orosis occurs where bones become very brittle. To reduce the likelihood for this, weight­-be­aring exercises can help maintain bone density and strength.

Increase in length As long as epiphyseal plate remains present, bones can increase in length. Cartilage cells divide making the epiphyseal plate thicker. At the same time the side of the plate closest to the diaphysis is replaced by bone. Therefore the diaphysis becomes longer and the epiphysis remains the same size.

Factors Affecting Develo­pment Stress (gravity or function and bone deposits and withdr­awal) , Hormones and Nutrition

Process: bone prominence or prolon­gation

Spine: a sharp process

Tubercle: small rounded projection

Trocha­nter: large blunt bony process

Fissure: deep grove or fold

Foramina: a little hole

Sinus: hole or cavity

Suture: joints of the skull, adjacent are united by fibrous membrane

Flexion: angle between articu­lating bones is decreased. Occurs in the median plane about a horizontal axis. Muscles respon­sible for flexion are called flexors
Examples: running and jumping movements, Arm bend for serve in tennis.

Abduction: away from body midline
Examples: taking one leg away from middle to side step.

Horizontal Flexion: moving arm forwards in horizontal plane (starting from abducted position)
Examples: throwing in sports, discus throw.

Rotation: moving a limb in a circular motion in either direction
Examples: movement in racket sports.

Hyper flexion: flexion of limb beyond normal limit
Examples: running and jumping movement at hip and knee

Pronation: palm face body
Examples: follow through tennis shot

Plantar flexion: extension of ankle, pointing of foot and toes
Examples: tippy toes

Elevation: superior direction movement
Examples: shrug shoulders

Protra­ction: movement forward (anter­iorly)
Examples: push shoulders forwards

Inversion: sole of foot turned inwards toward imaginary midline