Skeleton basics + AXIAL Flashcards
Connective tissues of the skeleton
Cartilage and bone
Avascular/aneural (no nerves)
Highly hydrated matrix
Chondrocytes
Growth only during development (interstitial and appositional, regeneration difficult)
Cartilage
Type of growth where the tissue expands by cell division
Interstitial Growth
Type of growth where the tissue expands in layers on surface. Old layers are degenerated.
Appositional Growth
Most common type of cartilage
Surrounded by dense perichondrium
Connects ribs to sternum, covering of all synovial joints, form supporting structures in trachea and bronchi
Provides stiff but somewhat flexible support. Reduces friction between bony surfaces.
Hyaline Cartilage
What type of cartilage?
Contains numerous elastin fibres
Resilient and flexible
Outer ear, epiglottis, auditory tube, cartilage of larynx, nose, etc.
Provides support but tolerates distortion without damage and returns to original shape
Elastic Cartilage
What type of cartilage?
Little ground substance
Densely interwoven collagen fibres
Durable and tough
Form intervertebral discs, pubic symphysis, between some joints (meniscus).
Resists compression, prevents bone-to-bone contact, and limits relative movement.
Fibrocartilage
Hydroxyapatite matrix
Osteocytes
Osteon organization
Highly vascularized
High resistance to compression, rigid.
Bone
INORGANIC COMPONENT OF BONE
Calcium phosphates
Provide resistance to compression, durability
Cause bone to be radiopaque
Hydroxyapatites
Weakness in bones due to low density of the hydroxyapatite.
Osteoporosis
Organic Components of Bone
Osteoclasts, Osteoblasts, Osteocytes, Osteoid.
Osteoclasts
Bone absorbing cells.
Organic component of bone.
Osteoblasts
Bone forming cells.
Organic component of bone
Osteocytes
Mature bone cells that maintain bone matrix
Organic component of bone
Osteoid
Unmineralized bony matrix
Organic component of bone
Osteoprogenitor Cell
Stem cell whose divisions produce osteoblasts
Spaces in which bone cells are present. Encase osteocytes in bones, and in cartilage they enclose chondrocytes.
Lacunae
Network of small canals
Canaliculi
Layers of compact matrix that surround a central canal. or weight-bearing concentric rings around Haversian canals (collagen fibres with mineralization).
Lamellae
Osteolysis
Osteoclasts degenerate the matrix of old bone.
Produces blood cells: erythrocytes, leukocytes & platelets.
Contains multipotent stem cells
Replaced every 120 days
Restricted to pelvis, ribs, end of long bones in adults. Found throughout the body in newborns.
Red (hematopoietic) Bone Marrow
Stores fat. Not volatile (last to be used).
Yellow Bone Marrow
Provides structure to body
Protects internal organs
Provides an anchor point for muscle contraction
Acts as a reservoir of minerals
Divisible into axial and appendicular
Skeletal System
Organized into osteons (Haversian systems).
Nerves and blood vessels pass through Haversian canals of osteons
Volkmann’s canals - perpendicular connections of Haversian canals.
Bone as an organ
Spongy bone, contains bone marrow (red for blood cell production and yellow for adipose deposition). Surrounded by periosteum.
Trabeculae
Superficial layer surrounding bone
Dense irregular connective tissue
Highly innervated
Isolates bone from surrounding environment
Participates in growth and repair
Continuous with joint capsule
Periosteum
Bone forms by replacing hyalin cartilage
Most of the bones in the body form via this type of ossification
Endochondral ossification
Bone develops from a fibrous membrane
Intramembranous ossification
Also known as dermal bone
Formation of most of the skull roof and portions of the clavicle and scapula
Fibrous tissue membrane formed by mesenchyme
Intramembranous Bone
Also known as replacement bone
Cartilaginous precursor is invaded by osteoblasts and replaced with bone.
Appositional growth only.
Endochondral Bone
Distal and proximal ends of the endochondral bone. Covered in hyaline cartilage.
Epiphysis
Shaft of endochondral bone. Main, long portion. Contains marrow.
Diaphysis
Area between epiphysis and diaphysis of the endochondral bone. Site of growth plate (epiphyseal plate).
Metaphysis
Skeleton begins to develop how many weeks in the embryo?
6-8
Primary ossification occurs in the ____?
Diaphysis. Expands from center of ossification towards epiphyses.
Secondary ossification occurs in the ____?
Epiphyses. Articular cartilage replaced by bone, reinforcing articular ends.
Ossification of _____ signals end of growth
Metaphysis. Finalized approximately 25 years of age in humans.
Skull, vertebral column, thoracic cage.
Axial Skeleton
Protects brain and guards entrances to digestive and respirator tracts. Contains 22 bones: 8 form the neurocranium and 14 form the viscerocranium. 7 additional bones (6 ossicles and the hyoid bone).
Skull
Houses and protects brain
Calvaria (frontal, occipital, parietal, temporal)
Cranial Base (spehnoid, ethmoid - cribriform plate)
Pterion
Neurocranium
passage of the central nervous system through the skull connecting the brain with the spinal cord.
Foramen magnum
Protect and support entrances of digestive and respiratory tracts
Protect delicate sensory organs
Maxilla
Nasal Conchae
Zygomatic bone (cheekbone)
Mandible
Viscerocranium
Skull Sutures/Fontanelles
At birth suture formation is incomplete, bones held together with un-ossified fibrous connective tissue.
Largest fontanelle. persists until 2 years old.
Anterior fontanelle
Intramembranous ossification of fontanelles leads to the development of the…
Calvaria bone. Bone formation takes place at numerous sites simultaneously.
Premature closure of the cranial sutures.
Craniostenosis
Nasal Region
Sinuses and nasal concha
Frontal, sphenoid, maxillary, and ethmoid. All connected to nasal passage. Are part of what?
Sinuses
Increase surface area of nasal passage.
Mucosal lining
Spiral orientation creates turbulence in airflow.
Nasal Conchae
Deciduous teeth
Baby teeth. 20 teeth total
Adult teeth
second dentition (permanent teeth)
32 teeth total
Consists of a series of bones
Support
Weight bearing
Flexible
Protects spinal cord and spinal nerves
Maintain upright body posture in sitting and standing
Vertebral Column
Spinal curvatures starting from top of body (connected to skull) to bottom
Cervical (concave posterior, lordosis)
thoracic (concave anterior, kyphosis)
lumbar (lordosis)
sacral (kyphosis)
coccyx.
how many of each vertebrae are there
7 cervical
12 thoracic
5 lumbar
5 sacral
3-5 coccyx
Lateral curvature and rotation of vertebrae
Congenital or neuromuscular disease
Many idiopathic
Scoliosis
What vertebrae is C1
Atlas
What vertebrae is C2
Axis
Fibrous outer ring of intervertebral discs
Anulus fibrosus
Gelatinous core, remnant of notochord
Nucleus pulposus
What is it called when the Anulus fibrosus elasticity declines with age
Protrusion of nucleus pulposus
Disc Herniation
Formed by:
12 pairs of ribs
sternum
costal cartilage
12 thoracic vertebrae
Surrounds thoracic cavity and supports the pectoral girdle
Provides protection for thoracic and abdominal contents
Thoracic Cage
True ribs
Ribs 1-7
Attach directly to sternum via own costal cartilage
False ribs
Ribs 8-10
Costal cartilages fuse and attach to costal cartilage of Rib 7
Floating ribs
Ribs 11-12
No connection to sternum
Costochondral
Rib 1-10 bone and costal cartilage
Sternocostal
Rib 1-7 costal cartilages to sternum
Costovertebral joints
Head of rib
Costal tubercle
Flat elongated bone consisting of three parts:
Manubrium
Body
Xiphoid process (indicates upper limit for liver, central tendon of diaphragm, and inferior border of heart).
Sternum
Fibrous joints that link two bones with a membrane or ligaments
Minimal movement
Example: skull sutures, interosseous membranes
Syndesmosis
Cartilaginous joints
bones united by fibrocartilaginous segments (example: costal cartilages of ribs, intervertebral discs, pubic symphysis)
or by temporary articular cartilage that then fuses during development to form synostoses joint type (example: hip bones before growth plate closure).
Synchondrosis
Most common joint
Free movement
Joint cavity
surrounded by joint capsule that has a membrane that secretes fluid (lubricant of joint), and around the outside is the fibrous capsule that supports the membrane and keeps the components of the joint connected.
Hyaline cartilage on articular surfaces
Example: knee joint
Synovial joints
