Skeletal System: Articular System, Skull and Cranial Fossae Flashcards
Functions of Bones
Support, protection, body movement
Forms a rigid framework to which the muscles of the body are attached; provides structural support
Skeletal system
encloses the brain
Skull
encloses the spinal cord
Vertebral column
(made of ribs and sternum: manubrium, sternal body and xiphoid process) – protects the heart, lungs (largest), great vessels, liver and spleen
Rib cage
T or F: Sites where blood cells are produced are protected within the spongy bone tissue of certain bones
T
2 attachments of muscles
origin and insertion
T or F: Skeletal muscles use bones as levers (with joints acting as pivots) to move the body
T
Process of blood cell formation
Hemopoiesis
T or F: All blood cells are made in the marrow (specifically white bone marrow) of certain bones
F, red bone marrow
Blood cell production is influenced by ________ which is produced by the kidneys which induces erythropoiesis
Erythropoietin
Lipid is stored in the adipose tissue within the _________ of certain bones
medullary cavity
Adipose tissues and lipid contents are known as ________ .
yellow bone marrow
Mineral which gives bones firmness and strength
Calcium and Phosphorous
Percentage of body’s calcium stored in bones
99%
Percentage of body’s phosphorous stored in bones
85%
Occurs throughout life (embryo -> adulthood)
Bone formation
Begins at about 4th week of embryonic development
Ossification/Bone formation
Bone tissues are derived from specialized migratory cells of mesoderm known as
_________
Mesenchyme
T or F: Before week 8, bones are made of fibrous membrane cartilage.
T
T or F: X-ray readings of children appear lighter due to incomplete ossification.
F, darker.
2 routes of ossification
Endochondral and Intramembranous
Stages of Endochondral Ossification
- Formation of bone collar around hyaline cartilage
- Cavitation of HC within the cartilage model
- Invasion of internal cavities by the periosteal bud and spongy bone formation
- Formation of medullary cavity as ossi continues
- Ossification of epiphyses; completed = HC remains only in the epiphyseal plates and articular cartilages
T or F: Hyaline cartilage remains only in the epiphyseal plates and articular cartilages when ossification is completed
T
Embryonic Mesenchymal Cells -> bone
Intramembranous Ossification
Embryonic mesenchymal cells -> chondroblasts -> cartilage matrix -> bone
Endochondral ossification
Ossification: Direct Mineralization from mesenchyme
Intramembranous Ossification
Intramembranous Ossification: example of bones
skull cap (calvaria), some facial bones, clavicle, scapula, pelvis, and part of mandible
Avascular organ; part of the fibrous layer of the eyes with no blood supply
Cornea
Cornea: Necessary nutrients are received with the help of fluid from _________
Ciliary humor
Due to the absence of direct blood supply, rejection after cornea transplant is controlled by _______ instead of immunosuppressant drugs.
Steroids
Bone classification accrdg to origin
Intramembranous and Endochondral
Bone classification accrdg to structure
Compact bone and spongy/cancellous bone
Commonly seen as a superficial layer of bone that is very hard and dense solid
Compact Bone
Consists of precise arrangements of microscopic cylindrical structures oriented parallel to the long ax
Compact Bone
Column-like structures that run parallel to the long axis of the bone; Matrix is laid down in concentric rings (lamellae)
Haversian System
Parts of Haversian System
Lamellae, Central Canal, Lacunae, Canaliculi, Perforationg (Volkmann’s) Canal
Parts of Haversian System: concentric layers that surround the central canals
Lamellae
Parts of Haversian System: contains minute nutrient vessels and nerves
Central canal
Parts of Haversian System: spaces that contain osteocytes connected to one another by tiny channels called canaliculi
Lacunae
Parts of Haversian System: tiny channels that process osteocytes and connect lacunae
Canaliculi
Parts of Haversian System: connect osteons with blood vessels and nerves
Perforating (Volkmann’s) Canal
Located deep to the compact bone tissue
Spongy/Cancellous Bone
Porous; with inner layer of honey-comb, flat, minute, needle-like projections called Trabeculae
Spongy/Cancellous Bone
inner layer of honey-comb, flat, minute, needle-like projections in Spongy/Cancellous Bone
Trabeculae
Bone classification accrdg to location
Axial and Appendicular
Found at the “axis” or the central line of the body
Axial
Bone classification accrdg to location: 80 bones
Axial
Found within the “appendages”; 126 bones
Appendicular
Netter’s number of appendicular bones
134 bones (8 sesamoid bones on both hands and feet)
Bone classification accrdg to shape
Long, short, flat, irregular, sesamoid bones
Much longer than they are wider; Bones of the limbs (usually has a shaft and 2 expanded ends)
Long bones
Cuboidal in shape
Short bones
Example of Short bone:
Carpal Bones: Scaphoid, Lunate, Triquetral, Pisiform, Trapezium, Trapezoid, Capitate, Hamate
Tarsal Bones: Talus, Calcaneus, Navicular bone, cuboid, 3 cuneiform
Thin, flattened and slightly curved type of bone
Flat bone
Other bones which cannot be classified as long, short or flat
Irregular bone
Ex. of flat bones
Scapulae, sternum, ribs, most boned of skull, facial bones except sphenoid and ethmoid
Ex. of irregular bones
Sphenoid and ethmoid, vertebrae, pelvic bone
Small nodules of bone; Found in certain tendons where they rub over bony surfaces; Protects tendon from excessive wear and tear by altering the direction of pull of a tendon
Sesamoid bones
Ex. of sesamoid bone
Patella
Point of articulation between bones; May or may not permit movement
Joint
Functions of joint:
o Weight bearing (knee and hip joints)
o Movement
o Stability (Hip joint)
o Lubrication
Joints accrdg to structure
Synovial, fibrous, cartilaginous
Bones are separated by joint cavity lubricated by synovial fluid; Enclosed in a fibrous joint capsule
Synovial joint
Type of joint: Shoulder, hip, elbow, knee, carpal, interphalangeal
Synovial joint