Skeletal System Skeletal System 2 Skeletal and Muscular System

Skeletal system Parts Blood Nervous tissue Bone tissue Cartilage Dense connective tissue Function Provide points of attachment for muscles Protect Support Produce blood cells Store salts

Support and Protection Support Give shape to body structures like the head and face Support the bodies weight Protection Bones protect the eyes, ears and brain, heart, lungs, and the reproductive and digestive organs

Types of Bones Long bones: long axes and expanded ends (legs and arms) Short bones: cube-like (wrists and ankles) Flat bones: plate-like (ribs, skull, scapula) Irregular bones: variety of shapes and usually connected to other bones (vertebrae, facial bones) Sesamoid bones: (round bones) small and imbedded in tendons (knee cap)

Parts of a Long Bone Epiphysis: expanded portion on each end Articular cartilage: hyaline cartilage that coasts the end of the epiphysis Diaphysis: shaft of the bone Periosteum: a tough vascular covering of dense connective tissue that encloses the bone Compact (cortical) bone: tightly packed tissue Has no spaces in it Spongy (cancellous) bone: bone with spaces in it Trabeculae: bony plates in spongy bone that help the bone weigh less yet remain strong

Parts of a Long Bone Medullary cavity: a hollow chamber where blood vessels and marrow is housed Endosteum: lines the medullary cavity Bone marrow: specialized soft connective tissue that is the site of blood cell formation

Bones Collagen the most abundant protein in animals Gives bones their strength and resilience Inorganic salts (calcium) make bones hard and resistant to crushing

Bone Development and Growth Osteoblasts: cells that will differentiate to form bone Osteocytes: bone cells Ossification: the formation of bone Bones begin to form during fetal growth and continue to develop and grow throughout adulthood

Bone Growth Epiphyseal plate: contains cells that are producing more new bone cells This growth happens until the epiphyseal plate meets the diaphysis, then bone lengthening is no longer possible **Throughout life, osteoclasts breakdown bone and osteoblasts replace it**

Bone growth and repair Factors that influence bone growth and repair: 1.Nutrition: vitamin D is needed so that bones have enough calcium 2.Hormones: growth hormones stimulate bone growth while sex hormones stimulate ossification of the epiphyseal plate 3.Physical exercise: pulling on muscles attached to bones stimulates bone tissue to strengthen

Body Movement Bones and muscles act as levers which have 4 parts: 1.A rigid bar (bone) 2.Fulcrum or place for the bar to pivot (joint) 3.An object moved against resistance (hand) 4.A force that uses energy to move the bar (muscle)

Blood Cell Formation Hematopoiesis: blood cell formation Bone marrow: found in medullary cavities of long bones, irregular spaces of spongy bone and in the central canals of compact bone Red bone marrow: formation of red blood cells (erythrocytes), white blood cells (leukocytes) and blood platelets (clotting proteins) Yellow bone marrow: store fat, the amount increase with age

Bone Marrow

Storage of Salts Calcium, phosphorous, magnesium, sodium, potassium and carbonate Calcium: important in nerve impulse conduction, blood clotting, muscle movement and other metabolic processes Stored in bones in the form of calcium phosphate

Parts of the Skeleton Axial skeleton: includes the skull, vertebrae, thoracic cage and hyoid bone Hyoid bone: supports the tongue and attaches muscles for swallowing

Skull (22 bones) Cranium: encloses and protects the brain Frontal bone: anterior portion of the skull above the eyes Supraorbital foramen: passageway for blood vessels and nerves Parietal bone: one on each side of the skull behind the frontal bone Occipital bone: back of the skull Foramen magnum: a large opening where nerves pass from the brain to the vertebral canal

Bones of the Skull Temporal bones: one on each side of the skull External acoustic meatus: leads to the inner ear Mandibular fossae: articulation site of the mandible Mastoid process: attachment for neck muscles Styloid process: attaches muscle of the tongue and pharynx Zygomatic process: helps form the cheek Sphenoid bone: forms the base of the skull Ethmoid bone: sides of the nasal cavity

Facial Bones Maxilla: upper jaw, roof of the mouth (hard palate) Palatine bones: lower cheek bones Zygomatic bones: cheek bones Lacrimal bones: bottom of the eye sockets Nasal bones: form the bridge of the nose Vomer bone: nasal septum Mandible: lower jaw

Infant skull Fontanels: (soft spots) places where the bones have not yet fused

Vertebral Column Intervertebral discs: fibrocartilage that acts as shock absorbers for the spine Vertebral foramen: space where the spinal cord can pass through Cervical vertebrae: 7 vertebrae of the neck Atlas: supports the head and turns the head up and down Axis: turns the head side to side Thoracic vertebrae: 12 vertebrae of the upper back where the ribs attach Lumbar vertebrae: 5 vertebrae of the lower back Largest to support the most weight Sacrum: 5 fused vertebrae, base of the vertebral column Coccyx: 4 fused vertebrae of the tailbone

Thoracic Cage Ribs: 12 pair attached to the 12 thoracic vertebrae Superior 7 are true ribs: join the sternum directly Next 5 pairs are false ribs: share an attachment site to the sternum Last 2 are floating ribs: no attachment to the sternum Sternum: breastbone Manubrium: upper section Body: middle section Xiphoid process: lower section that projects inward

Appendicular Skeleton Appendicular Skeleton: includes the pectoral girdle, the pelvic girdle and the upper and lower limbs Pectoral girdle: connects the bones of the upper limbs to the axial skeleton and aids in movement Scapula: shoulder blades Clavicles: collar bones

Upper Limbs Humerus: upper arm bone Radius and ulna: forearm bones Carpals: wrist bones (8 bones) Metacarpals: hand or palm bones (5 bones) Phalanges: finger bones (14 bones)

Appendicular Skeleton Pelvic Girdle: attaches the lower limbs to the axial skeleton. Pelvis: Includes the sacrum, coccyx and pelvic girdle Ilium: largest hip bone Ischium: lowest part of the hip Pubis: anterior portion of the hip

Lower Limbs Femur: thigh bone Patella: knee cap Tibia and fibula: lower leg bones Tarsals: ankle bones (7 bones) Calcaneus: heel bone Metatarsals: foot or instep bones (5 bones) Phalanges: toes (14 bones)