A & P Skeletal System

Functions?

support

protection

movement

storage of mineral and energy reserves

blood formation

support

viscera are supported by bones, limbs and spine support the body

protection

enclose organs

movement

actions of muscles on bones

storage of mineral and energy reserves

lipids, calcium, phosphate storage and release

blood formation

red bone marrow

mineralization aka calcification

the hardening of tissue due to the deposition of calcium salts

features of flat bones + EX

flat surfaced

cranial/frontal/corinal bones

features of short bones + EX

equal width and length

carpals and tarsals

features of irregular bones + EX

complex shapes

vertebral

features of long bones + EX

greater in length then they are wide

femur and humerous

osteogenic/osteoprogenitor cells

stem cells that develop from embroyonic mesenchyme from mesoderm

occurs in the endosteum and inner layer of periosteum ‘multiplys quickly

osteoblasts = builders/bone formers

synthesizes organic matter

promotes mineralization

osteogenisis occurs leading to osteocytes

osteocytes

becomes trapped in matrix

resides in lacunae and connected by gap junctions

osteoclasts = recycles

bone cells dissolve on surface

osteolysis occurs - breaks down

blood cell created from bone marrow stem cells

endocrine functions of osteoblasts

secretes osteocalcin

osteogenesis vs osteolysis

Genesis- formation of bones

Olysis- breaking down bone tissue

two main components of bone tissue

collagen and hydroxyapatite

matrix is 1/3 organic matter (collagen)

synthesized by osteoblasts providing flexibility

matrix is 2/3 inorganic matter (hydroxyapatite)

85% calcium phosphate (salt) provided inflexiability and strength

components of compact bone

lamellae

central canal

canaliculi

osteon

perforating canals

lamellae

layers of matrix (concentric, circumferential, and interstital)

central canal

center os osteon containing blood vessels and nerves

canaliculi

slender channels that interconnect the lacunae

osteon

structural & functional unit of compact bone; small cylindrical structure

perforating canals

run perpendicular to central canals, forms channel for vessels and nerves

structure of spongy bone - why is it important?

increases strength with minimum amount of weight

yellow vs red marrow

occupies the medullary/marrow cavity in long bones of adults but for red marrow its found in children

intramembranous ossification

produces the flat bones of the skull, most of the clavicle and part of mandible

1st ossification centers

2nd osteoid undergoes calcification

3rd woven bone and surrouding periosteum forms

4th lamellar bone replaces woven bone as compact and spongy bone form

endochondral ossification

process where bone develops from hyaline cartilage

starts around the 6th week of fetal development of and continues into 20s

consits of the primary and secondary ossification center

interstitial growth vs appositional growth

inter- how our bones get longer

app- deposition of new tissue at the surface

Epiphyseal plates

consits of growth and transitional zones moves from cartilage to bone (metaphysis)

hylaine cartilage is in the middle

intersitional growth occurs

wolffs law

The architecture of a bone is determined by the mechanical stress placed upon it - bone adopts to withstand them

forms of bone is shaped by its functional experience

calcium homeostasis

consists of hypocalcemia and hypercalcemia

deficiency of calcium ions in the blood

excess of calcium ions in the blood

role of parathyroid hormone and calcitriol

interacts with bones in repsonse to low blood calcium levels, increases the relase of calcium from bone in the blood while increasing osteoclast activity

role of calcitonin

released in response to high blood calcium levels

consits of osteoclasts inhibition: reduces osteoclasts activity by 7-% after 15 mins of secretion

and osteoblasts stimulatio: within an hour, increased activity of osteoblasts which depositis calcium into skeleton

aging of bone

tensile stregth of bone decreases due to reduced rate of protien sythesis by osteoblasts

amount of inorganic materials in the bone matrix inccreases

bone loss calcium and other minerals- bone become thinner and weaker

bones become brittle and more susceptible to fracure over time

consists of osteopenia and osteoporosis

osteopenia vs osteoporosis

Pen- early stage of bone loss

Por- more advanced and servere stage of bone loss

healing of fractures

1. a fracture hematoma forms

2. a fibrocartilaginous (soft) callus forms

3. a hard (bony) callus forms

4. the bone is remodeled

joint/articulation

any point where two bones meet = sutures

arthrology

study of joint structure, function and dysfunction

kinesiology

study of muscuskeleton movement

synovial fluid

rich in albumin and hyaluronic acid

tendons

strip of sheet of tough collangenous connective tissue

attached to muscle to bone

important for stabilization

ligament

similar tissue to tendon

attaches bone to bone

bursa

fibrous sac of synovial fluid located between adjacent muscles, where a tendon passes over a bone, between bone and skin

cushions muscles

helps tendons slide easily over joints

Classifications of Joints

Fibrous

Cartilaginous

Synovial

Fibrous Joint Types

Sutures

Gomphoses

Syndesmoses

Sutures

between bones of the skull

synarthroses joint - alls skull to grow during childhood

Gomphoses

between the teeth & sockets of the skull

Synarthroses joint

EX: articulations of the roots of individuals teeth and alveolar processes

Syndesmoses

between radius & Ulna and between tibia & Fibula

amphiarthrosis joint

Cartilaginous Joint Types

synchondroses

Symphyses

Synchondroses

bones bounded by hyaline cartilage

synarthroses joint

EX: cartilage of epiphyseal plate and costal cartilage

Symphyses

pad of fibrocartilage between articulating bones

resists compression and tension stressors (shock absorber)

EX: Pubic Symphysis and intervertebral joints

Synovial Joint Types

all diarthrosis are synovial joints

facing surfaces of two bones are covered with articular cartilage

these are seperated by joint cavities containing synovial fluid

Joint/articular capsule encloses the cavity and retains fluid

Joint capsule

encloses the cavity and retains fluid

Joint cavity

contains synovial fluid

Fulcrum

fixed point in the lever system (joint itself)

Resistance

load that the effort is working against (weight/gravity)

Effort

counterbalances the load (muscle)

First class lever

fulcrum (joint) is in the middle

known as the seesaw

EX: Atlanto-occipital joint

Second Class Lever

resistance (weight/gravity) is in the middle

known as the wheelbarrow

EX: bouncing knee & plantar flexion of the ankle joint

Third class lever

MOST COMMON

Effort (muscle) is in the middle

known as rowing

EX: forearm flexion

Types of Levers + middle

Fulcrum - 1st

Resistance - 2nd

Effort- 3rd

Range of motion is determined by?

1. Structure of articular surface of bones

2. strength & tautness (stretchy) of ligament & joint capsule

3. Actions of muscles & tendons

Classifications of Synovial Joints

Ball & Socket - multiaxial most mobile

Condylar - biaxial

Hinge - uniaxial

Plane- uniaxial, least mobile

Pivot - uniaxial joint

Saddle - biaxial

Joint movements

Gliding

Angular

Flexion/extension

Abduction/adduction

circumduction

rotational

rotation

cervical rotation

supination/pronation

special

elevation/depression

protraction/retraction

plantar flexion

dorisflexion

inversion

eversion

eversion

tips the soles laterally

inversion

tips the soles medially

dorisflexion

movement of foot where toes are elevated

plantar flexion

movement of the foot with toes pointing downward

protraction vs retraction

p = anterior movement of a body part

r= posterior movement of a body part

elevation vs. depression

e= raise body part vertically in frontal plane

d= lowers body part in frontal plane

special movements

occurs at specific joints and dont fit into other categories

supination vs pronation

s= forearm movement turns palm anteriorly or upward

p= opposite, palm facing posteriorly or downward

rotational

a bone pivots around its own longitudinal axis

circumduction

one end of an appendage remains stationary while other end makes circular motion

Abduction vs adduction

ABD- movement of body part in frontal plane away from midline

ADD- movement in frontal plane toward midline

Flexion vs extension

f= movement that decreases joint angle

e= movement that straightens joint and returns body part to zero position (hyperextension)

Angular

angle between articulating bones that can increase or decrease

Gliding

two opposing articular surface slide past each other

Compound (open) fracture

broken end of bones stick out and seen through the skin

compression fracture

broken bone appears when the body of the vertebrae collapses

Committed Fracture

Bone breaks into 3 or more pieces

Displaced Fracture

when at least 1 piece of bone is shifted out of alignment

Greenstick

when the bone does not break completely

Nondisplaced Fracture

bone breaks and keeps anatomical alignment

Stress fracture

thin fractures occur due to repeated stress impact = running

Simple (closed) fracture

bone is broken but does not puncture the skin