skeletal system notes
TRANSCRIPT
The Skeletal The Skeletal System:System:
Structure, Function, Structure, Function, and Diseasesand Diseases
of the bones and of the bones and jointsjoints
The Skeletal SystemThe Skeletal System Parts of the skeletal system
Bones (skeleton)
Joints
Cartilages
Ligaments (bone to bone)(tendon=bone to muscle)
Divided into two divisions
Axial skeleton
Appendicular skeleton – limbs and girdle
Functions of BonesFunctions of Bones
Support of the body
Protection of soft organs
Movement due to attached skeletal muscles
Storage of minerals and fats
Blood cell formation
Bones of the Human BodyBones of the Human Body
The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Homogeneous
Spongy bone
Small needle-like pieces of bone
Many open spaces
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Bones are classified by their shape:
1.long 2.short 3.flat 4.irregular
Classification of Bones on the Classification of Bones on the Basis of ShapeBasis of Shape
Classification of BonesClassification of Bones
Long bones
Typically longer than wide
Have a shaft with heads at both ends
Contain mostly compact bone
• Examples: Femur, humerus
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Diaphysis
Shaft
Composed of compact bone
Epiphysis
Ends of the bone
Composed mostly of spongy bone
Structures of a Long BoneStructures of a Long Bone Periosteum
Outside covering of the diaphysis
Fibrous connective tissue membrane
Sharpey’s fibers Secure periosteum to
underlying bone
Arteries Supply bone cells
with nutrients
Classification of BonesClassification of Bones
Short bones
Generally cube-shape
Contain mostly spongy bone
Examples: Carpals, tarsals
Classification of BonesClassification of Bones
Flat bones
Thin and flattened
Usually curved
Thin layers of compact bone around a layer of spongy bone
Examples: Skull, ribs, sternum
Classification of BonesClassification of Bones
Irregular bones
Irregular shape
Do not fit into other bone classification categories
Example: Vertebrae and hip
Surface features of bones
Sites of attachments for muscles, tendons, and ligaments
Passages for nerves and blood vessels
Categories of bone markings
Projections and processes – grow out from the bone surface
Depressions or cavities – indentations
Types of Bone CellsTypes of Bone Cells Osteocytes
Mature bone cells
Osteoblasts Bone-forming cells
Osteoclasts Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
Changes in the Human SkeletonChanges in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
Bone GrowthBone Growth
Epiphyseal plates allow for growth of long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified
Cartilage is broken down
Bone replaces cartilage
Bone FracturesBone Fractures
A break in a bone
Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
Common Types of FracturesCommon Types of Fractures
Stages in the Healing of a Bone Stages in the Healing of a Bone FractureFracture
Axial skeleton supports and protects organs of head, neck and trunk Axial skeleton:
skull (cranium and facial bones) hyoid bone (anchors tongue and muscles
associated with swallowing) vertebral column (vertebrae and disks) bony thorax (ribs and sternum)
Appendicular skeleton includes bones of limbs and
bones that anchor them to the axial skeletonAppendicular skeleton:
pectoral girdle (clavicles and scapulae)upper limbs (arms)pelvic girdle (sacrum, coccyx)lower limbs (legs)
Articulation- where joints meet, connect, and are formed.
22 bones in skull6 in middle ears1 hyoid bone26 in vertebral column25 in thoracic cage
4 in pectoral girdle60 in upper limbs60 in lower limbs2 in pelvic girdle
206 bones in all
The Axial SkeletonThe Axial Skeleton
Forms the longitudinal part of the body
Divided into three parts
Skull
Vertebral column
Bony thorax
The Axial SkeletonThe Axial Skeleton
The skull
8 sutured bones in craniumFacial bones: 13 sutured bones, 1 mandible
Craniumencases brainattachments for musclessinuses
Bones of the SkullBones of the Skull
Allows forgrowth
Human Skull, Superior ViewHuman Skull, Superior View
Human Skull, Inferior ViewHuman Skull, Inferior View
Figure 5.9
Paranasal SinusesParanasal Sinuses
Hollow portions of bones surrounding the nasal cavity
The Hyoid BoneThe Hyoid Bone
The only bone that does not articulate with another bone
Serves as a moveable base for the tongue
The Vertebral ColumnThe Vertebral Column
Vertebrae separated by intervertebral discs
The spine has a normal curvature
Each vertebrae is given a name according to its location
Vertebral column
7 cervial vertebrae12 thoracic5 lumbar1 sacrum (5 fused 1 coccyx (4 fused)
Vertebrae vary in size and morphology
Structure of a Typical VertebraeStructure of a Typical Vertebrae
Thoracic cageribsthoracic vertebraesternumcostal cartilages
True ribs are directly attached to the sternum(first seven pairs)Three false ribs are joined to the 7th ribTwo pairs of floating ribs
Joints• Fibrous-Fibrous joints connect bones without
allowing any movement. The bones of your skull and pelvis are held together by fibrous joints.
• Cartilaginous-Cartilaginous joints are joints in which the bones are attached by cartilage. These joints allow for only a little movement, such as in the spine or ribs.
• Synovial-Synovial joints allow for much more movement than cartilaginous joints. Cavities between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones. Bursa sacks contain the synovial fluid. within fixed limits
• A joint, or articulation, is the place where two bones come together.
• There are three types of joints classified by the amount of movement they allow:
Immovable slightly movable freely movable
Types of JointsHinge- A hinge joint allows extension and
retraction of an appendage. (Elbow, Knee)
Ball and Socket- A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders. (Hip, Shoulder)
Gliding- In a gliding or plane joint bones slide past each other. Mid-carpal and mid-tarsal joints are gliding joints. (Hands, Feet)
Saddle- This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (Thumb)
Structures Associated with the Structures Associated with the Synovial JointSynovial Joint Bursae – flattened fibrous sacs
Lined with synovial membranes
Filled with synovial fluid
Not actually part of the joint
Tendon sheath
Elongated bursa that wraps around a tendon
The Synovial JointThe Synovial Joint
Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape
Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape
Diseases and Conditions
of the Skeletal System
Arthritis
Bursitis• Inflammation of the Bursa sac• can become inflamed from injury
or infection• localized pain or swelling
Tendonitis• inflammation of the tendon.• movement becomes painful. • most common cause of tendonitis
is overuse.
Carpal Tunnel Syndrome
• swelling or change in position of the tissue within the carpal tunnel squeezes and irritates the median nerve.
• causes tingling and numbness of the thumb, index, and the middle fingers
Osteoporosis• means "porous bones." • bones have lost minerals
(especially calcium) making them weak, brittle, and susceptible to fractures
• most common places where fractures occur are the back, hips, and wrists.
Scoliosis• abnormal curvature of the spine. • one or more abnormal • More girls than boys have severe
scoliosis.
Kyphosis• spine may develop a hump. • can occur as a result of
developmental problems or degenerative diseases
Lordosis• A curvature of the vertebrae in the
lower back area, giving a "swayback" appearance.
Rickets• softening and weakening of bones
in children• usually because of an extreme and
prolonged vitamin D deficiency.
Gout• results from an overload of uric acid in
the body. • leads to the formation of urate crystals
that deposit in the joints. • crystals in the joints causes recurring
attacks of joint inflammation (arthritis). • Chronic gout may cause joint
destruction, decreased kidney function, and kidney stones.
Acromegaly• occurs when the body produces
too much of the hormones that control growth.
• tissues grow larger than normal. • excessive growth can cause
serious disease and even premature death.
Spina Bifida• birth defect that involves the
incomplete development of the spinal cord or its coverings.
• spina bifida literally means "split" or "open" spine.
• The condition usually is detected before a baby is born and treated right away.
Talipes Equinovarus- “Clubfoot”
• deformity of the whole foot that is present at birth.
• the child is born with the foot pointing down and twisted inwards at the ankle.
Sarcoma• Osteosarcoma• most common type of bone
cancer. most commonly found in children and adolescents
Myeloma• cancer in which abnormal cells
collect in the bone marrow and form tumors
Leukemia• cancer of the blood cells• starts in the bone marrow where
blood cells are • the bone marrow starts to make a
lot of abnormal white blood cells, called leukemia cells.
• leukemia cells don't do the work of normal WBC’s and they don't stop growing when they should.
Bone Marrow Biopsy