The Skeletal System Chapter 5 – Anatomy/Physiology NHS Dr. Smith

Skeletal System

Functions SUPPORT: Supporting Framework – “Where tissue hangs” PROTECTION: Protect Vital Organs/Blood Production MOVEMENT: Muscles pull bones (levers) STORAGE: Calcium-homeostasis HEMATOPOIESIS – making blood cells – in RED BONE MARROW of certain bones

TYPES OF BONES NAMES DEPICT SHAPE 1)LONG, 2)SHORT, 3)FLAT, 4)IRREGULAR

LONG BONES - PARTS Diaphysis – hollow tube made of compact bone Medullary Cavity – hollow area – contains yellow bone marrow Epiphysis – ends of bone – also contains spongy bone Periosteum – Fibrous Membrane (covering found everywhere but ends of long bone) Endosteum – lines the Medullary Cavity

Microscopy: BONE Outer layer: Dense/Compact Bone(Osteons) Porous bone (spongy bone) at end: Spongy Bone –filled with bone marrow Trabeculae – needlelike threads of spongy bone

Osteon Matrix of bone Composed of calcified matrix Each ring is called a concentric lamellae Central Canal in Middle – Contains blood vessels

Osteocyctes Living Components Lies in spaces called lacunae Periosteum – Hole opening in bone

Microscopy: CARTILAGE Firm Gel instead of calcified component Cartilage Cells – chondrocytes

Bone formation and growth Osteoblast – bone forming cells Osteoclast- bone reabsorbing cells Endochondral ossification – bones that form from cartilage Epiphysis– where bone becomes ossified at ends of bone Diaphysis – where bone becomes ossified - in the center of bones Epiphyseal Plate – cartilage plate that permits growth

Intramembranous ossification Video on this

Fracture repair Ist step- formation of hematoma( blood clot) In area of fracture 2 nd - step- Callus formation- fibroblasts make collagen fibers to span the fracture. Eventually become cartilage and then bone. Takes between 6-8 weeks normally 3 rd step- Remodeling of area of fracture so that bone appears as it did before fracture

Division of Skeleton Axial skeleton – skull, spine, chest (80 bones) Appendicular skeleton - upper and lower extremities (126 bones)

SKULL 8 cranium bones, 14 face bones, 6 ear bones Sutures –immovable joints Fontanels – “soft spots” Sinuses – spaces/cavities inside skull – Paranasal – NOSE – Maxillary- maxilla – Fronal- frontal bone

Spine Vertebrete- irregular shaped spine bonds Cervical 7, Thoracic 12, Lumbar 5, Sacrum-Coccyx 2

Thorax/Chest Sternum – breastbone 12 pairs of ribs – attach to vertebra – 14 true ribs - upper seven pairs attached by costal cartilage – 10 False ribs - lowest 2 pairs not attached to sternum “floating”; next three pair are attached to 7th rib

Upper extremities Scapula – shoulder blade Clavicle – collar bone Sternoclavicle joint – clavicle/sternum Humerous – upper long bone in arm Radius/Ulna – forearm bones 8 Carpals – wrist bones 5 metacarpals – palm bones 28 phalanges – finger bones

Hip and Pelvis Large coxal bone illium, ischium, and pubis grow together in an adult

Lower Extremities Femur – long bone – upper leg Patella – knee cap Tibia/fibula – lower leg bones 8 Tarsals – ankle bones 5 metatarsals – sole bones 28 phalanges – finger bones

Foot Arches Medial Longitudinal Arch - Inside of foot Lateral Longitudinal Arch - Outside of foot Transverse (metatarsal) arch - extends on the ball of the foot

Man/Woman Differences Male skeleton's larger Female’s pelvis supports childbirth - male’s pelvis is more narrow - female's pelvis angle is greater

Joints - ARTICULATIONS Synarthrotic joint - no movement Anphiarthrotic joint - slight movement Diarthrotic - free movement

Diathrotic Joint Allow for free movement All have a joint capsule, cavity, and a layer of articulating cartilage over the ends of the two joining bones ( synovial membrane in joint capsule Ligaments - fibrous connective tissue - hold joint together