CH6 Flashcards
Functions of skeletal system
+ Supports soft tissue and provides attachment sites for muscles. Frame the body and protect organs
+ Assists skeletal muscles in movement
Site for Hematopoiesis (blood cell formation/production), in the red marrow of bone (erythrocytes, leukocytes, platelets) . Yellow marrow is is site of triglyceride storage (adipose tissue)
+ Bones store and release minerals (calcium & phosphorus).
- Calcium is used for muscle contraction/neuron function
Compact bone (Cancellous)
+ Smooth, non porous surface of bone, 80% if bone makeup and found in areas of significant stress (diaphysis of long bones)
+ Composed of collagen and Calcium /phosphorus.
+ Functional unit is the Osteon (concentric rings of bone).
+ Highly vascular
Haversian System
- central canal of an osteon containing blood vessels and nerves
- Osteocytes (bone cells) are found in small holes called lacunae
Spongy Bone (aka Trabeculae bone)
- 20% bone makeup, very porous bone (sponge-like)
- found beneath compact bone and at the ends of epiphysis
- lighter than compact bone
- Contains Red bone marrow - site for hematopoiesis
Periosteum
Dense irregular connective tissue that wraps around diaphysis, nourishes and helps with fracture repair. Provides a passageway for blood vessels, lymphatics and nerves (nociceptors - pain receptors)
Periosteal arteries and veins
blood vessels that supply and drain blood to outer surface of bones
Osteon
functional unit of compact bone
Concentric Lamellae
cylindrical rings of bone matrix that surround osteons
Central Canal
- a passageway for blood delivery to each osteon (in the middle of an osteon)
Haversians canal
Nutrient Foramen
a passageway for arteries and veins to provide blood/nutrients to bone
Volkmann Canal
transverse (horizantal) tunnel for blood supply
Ligaments
Composed of dense regular tissue, avascular, connects bone to bone. Considered a sprain
Tendons
Composed of dense regular connective tissue, connect muscle to bone. Considered a strain
Cartilage
Found in areas where 2+ bones meet
Articular Cartilage (hyaline cartilage)
Most abundant type of cartilage, found on epiphysis. Reduces friction between bones
Fibrocartilage
found in joints, reduces compression stress, absorbs shock
Long bones
long diaphysis, grow in length/diameter, give us our height, found in arms, legs and fingers
-Femur, tibia, fibula, humerus, radius, ulna
short bones
box-like, short and stout bones
- carpal, tarsus
Flat bones
thin layer of spongy bone sandwiched between 2 layers of compact bone
- Skull bones, ribs, sternum, scapular, shoulder blade
Irregular bones
complex shapes, neither long or short
- vertabrae
Sesamoid bones
sesame shaped bones, develops within a tendon
- Patella
Sutural (wormian) bones
typically develop along the connections between the flat bones of the skull. Not all people have it
Diaphysis
shaft of long bone, compact bone
Epiphysis
proximal and distal ends of long bones, spongy bone
Metaphyses
small area between diaphysis and epiphysis
- Site of epiphyseal plate (growth plate)
epiphyseal plate (growth plate)
responsible for bone growth, rapid dividing chondroblasts
Endosteum
lining of medullary cavity
Medullary cavity
Red marrow in newborn infants, but as we get older yellow marrow increases
Foramen
hole - where blood vessels enter the bone
Fossa
depression or cavity
Sinus
cavity within a bone
Spine
sharp slender projection
Process
any point bony projection
Tubercle/tuberosity
small rounded projection
Trochanter
larger, blunt projection
Head
superior portion of long bone
Facet
smooth, flat articular surface
Condyle
rounded articular surface
Epicondyle
raised area near condyle
Bone cells
Osteogenic, osteoblasts, osteocytes, osteoclasts
- Both osteoclasts and osteoblasts are important in bone growth and repair and calcium homeostasis in the body
Osteogenic cells
repair and produce new bone
Osteoblasts
secrete osteoid and stimulate calcium phosphate deposition
create new bone tissue, strengthen bones, and repair breaks
Osteocytes
mature bone cells that maintain the matrix and initiate remodeling
maintain bone health
Osteoclasts
large, multinucleated cells that break down bone matrix, comes from bone marrow
Bone matrix
bone tissue made of collagen and calcium phosphate
When calcium declines
- Parathyroid Glands secrete PTH which increases osteoclast activity
- Osteoclasts remove Calcium (Ca 2+ ) from bone, and deposit into blood
When calcium increases
- PTH levels decrease & calcitonin secretion (from thyroid) increases
- Reduced osteoclast activity, continued osteoblast activity
- Excess Calcium, Ca 2+, deposited in bone
2 types of ossification (bone formation)
Intramembranous ossification and Endochondral ossification
Intramembranous ossification
a process that creates flat bones of the skull, face, and clavicle from fibrous connective tissue
Endochondral ossification
The process of replacing cartilage with bone to form the skeleton
bone growth: longitudinal
grows in length
bone growth: appositional
grows in width
- osteoblasts, deposit new bone tissue on the surface of existing bone
Proliferative zone
cartilage cells divide quickly, pushing epiphysis away from diaphysis
Hypertrophic zone
Cells grow larger causing lacunae to lengthen
Calcification zone
Matrix becomes calcified. Chondrocytes die and blood vessels invade leaving calcified slivers
Ossification zone
the slivers are eroded by osteoclasts and covered with new bone by osteoblasts. Marrow cavity elongates
Horomones that affect bone growth
hGH, sex horomones (estrogen and testosterone), thyroid, parathyroid, Glucocorticoids (cortisol)
hGH
stimulates mitosis in epiphyseal chondroblasts and initiates secretion of IGF (insulin like growth factor) from the liver
Sex hormones
(Estrogen and Testosterone): Increase both chondroblast and osteoblast activity, resulting in rapid growth during puberty. Osteoblast activity eventually overtakes chondroblast activity, sealing off growth plates
Thyroid
Thyroxine and Calcitonin are both necessary for bone growth. Calcitonin inhibits osteoclasts, causing more calcium to be deposited in bones
Parathyroid (PTH)
causes osteoclasts to dissolve bone, raising blood calcium
Glucocorticoids
slows cell division at epiphyseal plates
- Corstisol
Growth plate zones
4 zones - Proliferative zone, Hypertrophic, ossification, Calcification
Closed
Skin is unbroken
Open
Bones pierce skin
Transverse
Fracture is perpendicular to long axis of bone
Spiral fracture
Oblique fracture often caused by twisting
Comminuted
Multiple fractures resulting in many small pieces. Often requires surgical fixation
Impacted
One part driven into the other by compressive force
Greenstick
Partial fracture where only one side of bone is broken, only happens in children. Occurs when the bone is still developing and bendy
Oblique
fracture is diagonal to long axis
FOOSH injuries
fall on outstretched hand
Colles fracture
distal radius fracture; falling on ventral part of hand (wrist extension)
Smith fracture
distal radius fracture; falling on dorsal part of hand (wrist flexion)
Salter Harris fractures
fracture involving the growth plate (epiphyseal plate)
+ Type II most common - fracture cuts through most of the growth plate and the metaphysis, breaks at an angle from rotation or twisting. Common in children age 10+
