skeletal system

Skeletal System

Skeletal System

206 bones Functions

1. Supports body and provides shape2. Protects internal organs3. Movement and anchorage of muscles4. Mineral storage (Calcium and Phosphorus)5. Hemopoiesis (red marrow of the bone is the

site of blood cell formation – red marrow is in long bones (epiphyses), sternum and ilia).

Bone formation

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Microscopic mature bone cells

Osteocytes = mature bone cell

Osteo = boneCyte = cell

Bone formation

Ossification – new minerals deposit to form bone

Begins at 8 weeks gestation

Minerals replace previously formed cartilage.

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Bone formation

Infants bones are soft and pliable because of incomplete ossification.

As bones ossify, they become hard.

Long bones grow in length and ossify from the center to the ends.1.02 Remember the

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Know the following….

Osteocytes = mature bone cells

Osteoblasts = cells that actually form bone

Osteoclasts = cells that tear down old bone

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Bone formation

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Types of Bones

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Long bones

Found in the arms and legs

Diaphysis – shaft

Epiphyses – ends

Medullary cavity – center of shaft, filled with yellow bone marrow, which is mostly fatty cells, also cells that form white blood cells

Endosteum- lines marrow cavity

Chewing with movable skull bone = mandible

Occipital bone connects with spinal column

Axial Skeleton Skull

frontal view

What are the structures of the frontal view of the skull.

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Axial Skeleton Skull

lateral view

What are the structures of the lateral view of the skull.

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Axial – skull, spinal column, ribs, sternum, hyoid

(u-shaped bone in neck to which the tongue is attached)

Appendicular – shoulder girdle, arms, pelvis, legs (126 bones total)

Axial Skelton

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Hyoid Bone

What is unique about the hyoid bone?

Vertebral Column

Spine – Vertebral Column

Encloses the spinal cord Vertebrae – separated by pads of cartilage

Intervertebral discs Cervical Vertebrae (7)

Atlas – 1st cervical vertebrae Axis – 2nd cervical vertebrae

Thoracic Vertebrae (12) Lumbar Vertebrae (5) Sacrum Coccyx

Appendicular Skeleton

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Shoulder girdle

Clavicle, scapula, humerus

Appendicular skeleton

Clavicle = collar bone

Scapula = shoulder blade

Humerus = upper arm

Radius and ulna = lower arm (radius = thumb side)

Carpals = wrist bones held together by ligaments

Metacarpals = hand bones

Phalanges = fingers

Pelvis = 3 bones (ilium, ischium, and pubis)

Femur = upper leg, longest and strongest bone in the body 1.02 Remember the

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Tibia and Fibula = lower leg (tibias touch – tibia is larger of the two bones)

Sternum = breast bone

Patella = kneecap

Tarsal bones = ankle bones

Calcaneus = heel bone

Metatarsals = foot bones

Appendicular Skeleton

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Pelvis

Pelvic girdle = ilium, ischium and pubis

Joints

Joints are points of contact between 2 bones- classified according to movement: Diarthrosis – movable Amphiarthrosis – partially movable Synarthrosis – immovable

Articular cartilage – covers joint surface Synovial Fluid – lubricating substance in

joints

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Joints Ball and socket

One bone has a ball at one end The other has a concave socket Allows for the greatest range of

motion Ex: shoulder

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Joints

Hinge joint

Move in one direction

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Joints:Diarthroses

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Example of a hinge joint.

Define uniaxial…permits movement in one axis only

Joints

Pivot joints

Bones that rotate across each other

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Joints

Gliding joint

Bones with flat surfaces that slide across each other

i.e. bones in ankle and hand

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Joints

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Amphiarthroses

Partially movable joints

Joints

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Synarthroses

Immovable joints Connected by fibrous

connective tissue

Bursa and Synovial Membrane

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Bursa Fluid-filled sac that

contains the synovial membrane

Lined by synovial membrane

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Synovial membrane Capsule that

encloses a joint

Lines the bursa Contains synovial

fluid

Bursa and Synovial Membrane

Types of movement

Flexion is a position that is made possible by the joint angle decreasing.

Extension

A movement of a joint in which one part of the body is moved away from another.

i.e. going from sitting to standing

AbductionA motion that pulls a structure or part away the midline of the body.

AdductionA motion that pulls a structure or part towards the midline of the body

Circumduction

The circular or a more precise movement of a body part, such as a ball-and-socket joint or the eye.

Rotation

A motion that occurs when a part turns on its axis.

i.e. shaking your head “no”

Pronation A rotation of the

forearm that moves the palm from an anterior-facing position to a posterior-facing position, or palm facing down.

Supination

The opposite of pronation, the rotation of the forearm so that the palm faces anteriorly, or palm facing up.

Arthritis

Arthritis = An inflammation of one or more joints.

Osteoarthritis- degenerative, occurs with aging, 80% of Americans suffer, joints become enlarged and painful

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Disorders of the Skeletal System

Arthritis Rheumatoid arthritis = A chronic,

autoimmune disease = joints become swollen and painful, joint deformities common

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Disorders of the Skeletal System

Rheumatoid arthritis

Osteoarthritis

Gout

Increase of uric acid deposited in joint cavity, mostly the great toe in men.

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Disorders of the Skeletal System

Osteoporosis- most of those affected are women.

Mineral density of bone is reduced 35% – 65%. The loss of bone mass leaves the bone thinner, more porous and more prone to fracture. (soft like a sponge)

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Disorders of the Skeletal System

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Osteoporosis

How do you think osteoporosis treated?.

Why is her height decreasing?

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Disorders of the Skeletal System

Rickets

Found in children, caused by lack of vitamin D, bones become soft.

Is this a common problem in the US? Why or why not?

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Disorders of the Skeletal System

Normal legs

Abnormal spinal curvatures Kyphosis Lordosis Scoliosis

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Disorders of the Skeletal System

hunchbackswayback

Dislocation Separation of

bones in a joint

Subluxation = partial separation (dislocation) 1.03 Understand the

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Skeletal System Trauma

Fracture- a break in a bone Treated by:

Closed reduction- cast or splint applied Open reduction- surgical intervention with

devices such as wired, metal plates or screws to hold bone in alignment

Traction- pulling force used to hold the bone in place

Used for fractures of long bones

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Skeletal System Trauma

Closed or simple bone broken, broken ends don’t break skin

Open or compound broken bone pierce the skin, can lead to infection

Greenstick in children, bone bent and splintered but

never completely separates Comminuted

splintered or broken into many pieces Spiral

bone twists, resulting in one or more breaks

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