Skeletal system Flashcards
Components of the skeletal system
bones, cartilage, ligaments, other connective tissues
bone
Primary organs of the system, form rigid framework of the the body, perform multiple other functions
Types: compact and spongy
Compact bone
dense or cortical bone; relatively dense connective tissue; appears white, smooth, and solid; 80% of bone mass
Spongy bone
cancellous or trabecular bone; located internal to compact bone; appears porous; 20% of bone mass
Cartilage
Semi- rigid connective tissue; more flexible than bone
Types: Hyaline cartilage, fibrocartilage
Hyaline cartilage
attaches ribs to the sternum; covers the ends of some bones, cartilage within growth plates; model for formation of most bones
Fibrocartilage
Weigh- bearing cartilage that withstands compression; forms intervertebral disks and cartilage pads of the knees
Ligaments
anchors bone to bone
Tendons
anchors muscle to bone
In what 3 locations do you use fibrocartilage?
Intervertebral disks, the pubic symphysis, and the cartilage pads of the knee joints
Basic functions of bone
Support and protection; movement; hematopoiesis; storage of mineral and energy reserves
Hematopoiesis
The process of blood cell production, occurs in red bone marrow connective tissues and contains stem cells that form blood cells and platelets.
Calcium is one of the minerals stored and released from bone. What are some of its functions within the body?
Muscle contracting, blood clotting, nerve impulse transmission
Classification of bones
Determines by shape: long bone, short bone, flat bones, irregular bones
Long bones
Greater in length than width; have elongated, cylindrical shaft (diaphysis); most common bone shape, found in upper and lower limbs; vary in size; ex. femur, humerus
Short bones
Length nearly equal to width; carpal bones (wrist bones); sesamoid bones- bones along tendons of muscles; patella, targets sesamoid bone
Flat bones
Flat, thin surfaces, may be slightly curves; provides surfaces for muscle attachment; protecting underlying soft tissue; form: roof of the skull, scapulae, the sternum, the ribs
Irregular bones
Have elaborate shapes; vertebrae, ossa coxae; (hip bones); several bones in the skill (ethmoid, sphenoid)
What types of bones have a length nearly equal to their width?
Short bones
Diaphysis
Elongated, usually cylindrical shaft; provides for leverage and major weight support; compact bone within thin spicules of spongy bone extending inward
Epiphysis
Knobby regions at the ends of ling bone; Proximal epiphysis (closest to the trunk); Distal epiphysis (furthest from the trunk); made of: outer thin layer of compact bone, inner region of spongy bone (primarily spongy bone), joint surface covered by thin layer of hyaline cartilage (termed articular cartilage it helps to reduce friction and absorb shock in moveable joints)
Metaphysis
region of mature bone between diaphysis and ephysis
Periosteum
Tough sheath outer surface of bone; outer fibrous layer of dense irregular connective tissue; protects bone from surrounding structures; anchors blood vessels and nerves to bone surface; attachment site for ligaments and tendons; inner cellular layer includes osteoprogenitor cells, osteoblasts, and osteoclasts; attached to bone by numerous collagen fibers (perforating fibers)
Endosteum
Covers all internal surfaces of bone within medullary city; incomplete layer of cells; contains osteoprogenitor cells, osteoblasts, and osteoclasts; though sheath covering outer surface of bone
What portion of the bone contains the epiphyseal plate?
The metaphysis
Gross anatomy of short, flat, and irregular bones
external surface composed of compact bone; interior composed of spongy bone (also called diploë in flat skull bones; lack a medullar cavity
Blood supply of bone
Bone highly vascularize, especially spongy bone; vessels entering from periosteum
Nutrient foramen
Small opening or hole in the bone; artery entrance and vein exit here
Nerve that supply bone
Accompany blood vessels through foramen; innervate bone, periosteum, endosperm, and marrow cavity; mainly sensory nerves
Bone marrow
soft connective tissue of bone; includes red and yellow bone marrow
Red bone marrow
Myeloid tissue; hematopoietic (blood cell forming); contains reticular connective tissue, immature blood cells and fat; in children located in the spongy bone and medullary cavity of long bones; in adults, located in portions of axial skeleton, located in proximal epiphyses of humerus and femur; e.g., skull, vertebrae, ribs, sternum, ossa coxae
Yellow bone marrow
Product of red bone marrow degeneration; fatty substance; may cover back to red bone marrow; may occur during sever anemia (condition with reduced erthyrocytes/ red blood cells) facilitates the production of additional erthyocytes
Where is red bone marrow found in the adult skeleton?
Proximal epiphyses of humerus and femur and portions of the axial skeleton: skull, vertebrae, ribs, sternum, and ossa coxae
Bone connective tissue
Primary components of bone, also called osseous connective tissue, composed of cells and extracellular matrix
Cells of the bone
Osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts
osteoprogenitor cells
Stem cells derived from mesnchyme; produced cells that mature to become osteoblasts; located in periosteum and endosteum
osteocytes
mature bone cells derived form osteoblasts; have lost bone forming ability; maintain bone matrix; detect mechanical stress on bone; may trigger deposition of new bone matrix
osteoblasts
often positioned side by side on bone surfaces; synthesized and secrete osteoid, initial semisolid form of bone matrix, later calcify; become entrapped within the matrix they produce
osteoclasts
large, multicellular, phagocytic cells; derived from fused bone marrow cells; ruffled border to increase surface area exposed to bone; often located within or adjacent to a depression or pit on bone, termed resorption lacuna; involved in break down bone
Organic components
osteoid produced by osteoblasts: collagen protein, semisolid ground substance of proteoglycans, glycoproteins; give bone tensile strength by resisting stretching; contribute to bone flexibility
Inorganic components
Made of salt crystal, primarily calcium phosphate, Ca3(PO4)2; Interacts with calcium hydroxide, forms crystals of hydroxyapatite Ca10(PO4)6(OH)2; other substance incorporated into crystal, e.g., calcium, carbonate, sodium, magnesium ions; crystals deposited around collagen fibers; harden the matrix and account for relative rigidity of bones
Proportion of organic and inorganic substances
correct proportion allows optimal functioning; loss of protein resulting in brittle bones; insufficient calcium resulting in soft bones