Overview of Anatomy and Physiology Functions of the skeletal system – Support – Protection – Mineral storage-calcium/phosphorus – Movement – Hemopoiesis Structure of bones – Long, short, flat, and irregular
Functions of the Skeletal System Support – Rigid framework – Supports against pull of gravity – “hanger” for our muscles!
Functions of the Skeletal System Protection – Soft body parts – Brain – Heart – Lungs – Vascular system
Functions of the Skeletal System Movement – Provide sites for muscle attachment – Bones and muscles work together as simple mechanical lever systems to produce body movements.
Functions of the Skeletal System Mineral Storage – The bones serve as a storage specifically for 2 minerals—calcium and phosphorus – Intercellular matrix of bone contains large amounts of… Calcium When blood calcium levels drop Calcium is released from the bones Excess Calcium is stored in the bone
Functions of the Skeletal System Storage – Bone tissue contains smaller amounts of… Sodium Magnesium Potassium Carbonate
Functions of the Skeletal System Hematopoesis – Blood cell formation – Takes place in red marrow of bones – Infants primarily have red marrow – As we age red marrow changes to yellow marrow for fat storage
Functions of the Skeletal System Hematopoesis (cont.) – Adults Red marrow is limited to the spongy bone – Skull – Ribs – Sternum – Clavicles – Vertebrae – Pelvis
Functions of the Skeletal System Red Marrow Functions – Formation of… Red Blood Cells White Blood Cells Blood Platelets
Functions of the Skeletal System Red Marrow (summary) – Manufactures blood cells – Found in ends of long bones – Center of other bones Yellow Marrow (summary) – Shaft of long bones – Composed largely of fat
Bones Bones stop growing in length by late teens, early 20’s Children- bone repair is much faster Elderly- past active phase, repair takes longer, bones more fragile
Types of Bone Types of Osseous/Bone Tissue Cancellous – Spongy Epiphysis, end of long bone & center or others Filed with red marrow Cortical – Compact Diaphysis, shaft of long bone Outer layer of other bones Haversion canal contains nerves and blood vessels
Types of Bones Short bones and flat bones – Cancellous/spongy covered by Cortical/compact Irregular – e.g. vertebrae Long bones – Ends are Cancellous/Spongy – Shafts are Cortical/Compact
Types of Bone Four classifications based on form and shape: – 1. Long – eg. Humerus – 2. Short – eg. Phalanges of the fingers – 3. Flat – eg. Occipital, sternum – 4. Irregular - eg. Vertebrae
Classification Long Bones: longer than they are wide Short Bones: – roughly cube-shaped – Vertical and horizontal dimensions approx. = – E.g. Wrist, ankle
Classification Flat bones: – Thin, flattened, usually curved – Made like sandwich with a middle layer of spongey bone called diploӫ. The diploӫ is covered on each side by a layer of compact bone. – E.g. Cranium
Classification Irregular Bones – One of a group of bones having peculiar or complex forms E.g vertebrae
Bone Membranes Periosteum – Membrane on outside of bone – Contain osteoblasts Endosteum – Lines marrow cavity – Cells aid in growth and repair
Bone Cells and Actions Osteoblasts- build bone Osteocytes- are mature bone cells Osteoclasts- break bone down
Projections Head- rounded knob – At end of bone – E.g. ____________________ Process- large projection – E.g. Spinous process on vertabrae Crest- border or ridge – E.g. __________________ Spine- sharp projection – E.g. spine of scapula
Depressions or Holes Foramen- hole allows vessel or nerve to pass through Sinus- air space in some skull bones Fossa- depression Meatus- short channel or passage – E.g. Passage to inner ear
12 Ribs True Ribs – First seven pair – Attach to sternum by costal cartilage False Ribs – Next five pair 8 th, 9 th, & 10 th attach to rib above 11 th & 12 th have no anterior attachment (Floating ribs)
Vertebral Column Cervical vertebrae- 7, support & move head Thoracic vertebrae- 12, ribs attached here Lumbar vertebrae- 5, support weight Sacral vertebrae- 5, fuse to single bone Coccyx – 4-5 in child – Fuse to 1 in adult
Bursa – Fluid-filled sacs – Joint movement Fascia – Connective tissue – Includes tendons, ligaments, and aponeuroses Tendons – Attach muscle to bones Ligaments – Bind joints together
Overview of Articulations Articulations (joints) Connect bones and allow movement – Three types according to degree of movement Synarthrosis—no movement Amphiarthrosis—slight movement Diarthrosis—free movement
Joints Diarthrosis-freely moveable – Hinge: elbow, knee – Ball and socket: hip and shoulder – Pivot: skull and 1 st vertabrae Synarthrosis-immovable – Sutures Amphiarthrosis-slightly movable – Vertebrae and pelvis
Diarthrosis Hinge: permitting only flexion and extension as in the elbow and knee joints. Gliding: Flat or slightly flat surfaces move against each other allowing sliding or twisting. This happens in the carpals in the wrist and the tarsals in the ankle.
Diarthrosis Ball-and-Socket: The ball-shaped end of one bone fits into a cup shaped socket on the other bone allowing the widest range of motion including rotation. Examples include the shoulder and hip. Pivot: An example is the joint between the axis and atlas in the neck.
Diarthrosis Articulating Joints – Covered with articular cartilage – Have joint capsules Outer layer-fibrous Inner layer- synovial, secretes synovial fluid to lubricate joints
Structure of a freely movable (diarthrotic) joint.
Synovial Joint Movement Flexion-decreases angle between bones (close fingers) Extension-increases angle between bone (open fingers) Abduction-movement away from midline Adduction-movement toward midline