Week 6 Science and Scholarship: MSK Flashcards
what is meant by the axial body
centre body mass (midline)
what is meant by the appendicular body
limbs off the trunk
how many bones in the axial skeleton
80 bones
how many bones in the appendicular body
126 bones
functions of the skeletal system
-protect and support internal organs and tissues,
-facilitate movement,
-store minerals,
-produce blood cells
-store fat
what is meant by the skeleton has a role in protection
it encloses internal organs and organ systems
what is meant by the skeleton has a role in support
rigid structural framework
what is meant by the skeleton has a role in movement
anchors skeletal muscle
what is meant by the skeleton has a role in mineral storage
stores minerals for homeostasis and ion balance
what is meant by the skeleton has a role in RBC production
red bone marrow is the site of haematopoisesis
what is meant by the skeleton has a role in energy storage
yellow bone marrow is the site of fat storage
identify the 5 basic types of bone
- Long bones
- Short bones
- Flat bones
- Sesamoid bones
- Irregular bones
what is a long bone
- Cylindrical in shape; longer than they are wide
- Leverage for movement
what is a short bone
- Cube-like in shape; equal in dimensions
- Stability, support & some movement
eg of long bone
femur, ulna and phalanges
eg of short bone
carpals and tarsals
what are flat bones
- Thin; often curved
- Muscle attachment & protection of organs
eg of flat bone
ribs, sternum and cranium
what are irregular bones
- Complex, no clear characteristic shape
- Protection of organs
what are sesamoid bones
- Small, ball-like
- Protection for tendons
eg of sesamoid bone
patella
eg of irregular bones
vertebra, facial bones
what are the two types of bone
compact and spongy aka cortical vs trabecular
differences between compact and spongy bone
*compact bone = outer edge of bone vs spongy bone= inner bone lattice
*compact bone = prominent in the diaphysis vs spongy bone = prominent in the head of bones
*compact bone contains osteons / haversion system vs spongy bone contains trabecular
*compact bone = strong in uniform direction vs spongy bone = strong in multiple directions
identify the major components of long bone
diaphysis,
epiphysis,
metaphysis,
medullary cavity,
articular cartilage,
periosteum
endosteum
what’s the diaphysis
shaft that is made up of cortical bone
what is the epiphysis
ends of bone that are made of trabecular matter
what is the metaphysis
between the diaphysis and the epiphysis (it is spongy bone)
what is the medullary cavity
marrow cavity in the diaphysis
what is articular cartilage
covers epiphyses to decrease friction
what is periosteum
Tough outer fibrous membrane covering bone (except the articulate cartilage)
function of periosteum
- Protects vessels & nerves that nourish bone
- Anchors muscle to bone
function of endosteum
*Maintains cellular environment during bone repair/remodelling
what is endosteum
thin, delicate membrane lining medullary cavity
identify three main types of connective tissue
Connective tissue proper
Dense
Loose
describe connective tissue proper
contain variety of cells & proteins suspended in viscous ground substance (extracellular matrix)
-can be loose or dense(reg/irreg)
function of supportive connective tissue
provide structural strength and protect soft tissue; few distinct cell types with densely packed fibres
identify bone cells
Osteoprogenitor, Osteoblasts, Osteocytes & Osteoclasts
what makes up ECM in bone
- Organic components = Collagen fibres (type 1)
- Inorganic components = Mineral salts
*Calcification
features of osteoprogenitor/ osteogenic cell
- Mesenchymal stem cell
- Only bone cell to undergo mitosis
- Some will become osteoblasts (a process called differentiation)
where are osteoprogenitor cells found
lines surface/edges of bones
features of osteoblasts
- Bone forming cell
- Synthesises and deposits the organic bone matrix (collagen fibres)
- Initiates calcification – impregnation of inorganic substances into bone matrix (hardens bone)
- Become (differentiate) osteocytes when encased/trapped in own bone deposits
where are osteoblasts found
lines surface/edges of bones
features of osteocytes
- Maintain bone microenvironment
- Delicate cellular projections (fingers) create a sensory network through bone matrix
- Regulate other bone cells
where are osteocytes found
- Cell Body = inside small cavities in bone (Lacunae)
- Cellular Projections = travel through small canals (Canaliculi)
outline the lineage of bone cells
- mesenchymal cell ( osteoprogenitor )–> osteoblast –> osteocyte
*WBC’s –> osteoclast
features of osteoclast
- Differentiate from haematopoietic stem cell
- Fusion of monocyte/macrophage type cells
- Large multinucleated cell with ruffled basal surface
- Creates a suction (sealing zone) on bone to break down bone matrix (i.e. Resorption)
where are osteoclasts found
edge of bones in resorption pits
identify the major components of Haversian system/ osteon
-lacuna
-canaliculi
-central Haversian canal (allow vessels and nutrients)
-concentric lamellae (bone rings)
what are volkmanns canals
horizontal canals for vessels that connect adjacent osteons
what are interstitial lamella
old osteons no longer containing Haversian canals
identify the major components of spongy bone
lamella
lacuna and canaliculi
identify functions of cartilage
- Maintains shape
- Resist compression & absorbs shock
- Provides smooth surface to minimise friction
what cells make up cartilage
chondroblasts and chondrocytes
function of chondroblasts
secrete cartilage ECM
what are chondrocytes and where are they found
- chondroblasts trapped in cartilage matrix
-found in lacuna (no need for extensions ergo no canaliculi)
what is found in cartilage ECM
-collagen type 2 and chondroitin t/f watery and rubbery
identify the three types of cartilage
hyaline / articular
fibrocartilage
elastic
hyalin cartilage appearance
smooth, clear and glassy
function of hyaline cartilage
prevents friction and holds airways open
where is hyaline cartilage found
on the ends of long bones at moveable joints
appearance of fibrous cartilage
-Rows of chondrocytes in lacunae; extensive parallel bundles of collagen
function of fibrocartilage
resist compression and absorb shock
where is fibrocartilage found
intervertebral discs
appearance of elastic cartilage
web like mesh of elastic fibres amongst lacunae
function of elastic cartilage
Provides flexible, elastic support; maintains shape
where is elastic cartilage found
outer ear and epiglottis
define ossification
formation and remodelling of bone tissue
name the two methods of bone ossification
-intramembranous ossification
-endochondral ossification
outline intramembranous ossification
-ossification centre is developed
-osteoblasts begin produce bone at ossification centres
-osteoblasts become trapped –> osteocytes
-calcification is promoted
-trabeculae form
-bone continues to be remodelled by cells
egs of intramembranous ossification
flat bones of skull
clavicle
mandible
outline endochondral ossification
-MSC divide into chondrobalsts
-chondrolasts lay down cartilage tissue
-they become trapped –> chondrocytes
-hyaline model begins to expand
-chondrocytes burst (change pH)
-ossification at bone ends (epiphysis)
-primary ossification centres form
-these centres continue to be remodelled
-secondary ossification centres form
-epiphyseal line formation
name two types of bone growth
interstitial and appositional growth
what is interstitial growth
bone grown in length
-occurs at epiphyseal plate
what is appositional growth
bone grown in width
-deposit bone on outside of bone
epiphyseal plate vs epiphyseal line
the plate is cartilage and allows growth vs line is fused bones
what is bone modelling
-osteoclasts removing bone at the same rate as osteoblasts forming bone tissue
-finding balance in bone cell functions
what are the factors effecting bone modelling
-Nutriton
-Hormones
-Disease
-Age and motility
what causes bone growth and bone loss
-bone growth occurs if osteoblasts are more active than osteoclasts
-bone loss if osteoclasts are more active than osteoblasts
how does nutrition impact bone modelling
adequate minerals and vitamins are essential to bone integrity
eg Vitamin D,C and calcium and phosphate
how do hormones impact bone modelling
-growth and sex hormones at puberty can impact bone growth
-loss of oestrogen at menopause can lead to post menopausal osteoporosis
-Calcitonin (limits reabsoprtion of Ca)
-PTH (increases reabsoprtion of Ca)
how does disease impact bone modelling
Cancers and inflammation can release factors that suppress new bone formation
how does age and motility impact bone modelling
-cells become less active as one ages
-takes more energy to build bone compared to break down bone
Outline the process of bone fracture repair
1.blood clot formation
-macrophages phagocytose any fragments/debris
2.Formation of fibrocartilaginous callus
-fibroblasts and chondroblasts form a mould
3.Formation of bony callus
-spongy bone begins to form at ends
4.Remodelling
-normal functions of bone cells to create trabecular and cortical product
list the time ranges for each stage of bone fracture repair
1) hours -days
2) days-weeks
3) 3-4 months
4) years
list the structural classes of joints
bony
fibrous
cartilaginous
synovial
list the functional classes of joints
synarthrosis
amphiarthrosis
diarthrosis
what is a bony joint +eg
complete fusion of two bones
-hip (os coxae) and frontal bone
what is a fibrous joint +eg
held together by dense collagen fibres
-syndesmosis of ankle
what is a cartilaginous joint+eg
held together by cartilage (hyaline or fibrocartilage)
-pubic symphysis , sternocostal joint of rib 1
what is a synovial joint+eg
held together by a fibrous joint capsule and ligaments, and contains a joint space between bone ends
-knees, knuckles, elbow
what is a synarthrotic joint
immobile , with no movement
what is amphiarthrotic joint
partial, minor movements possible
what is a diarthrotic joint
freely mobile, large range of movements allowed
synovial joint is a ____ joint
diarthrotic
fibrous joint is a ___ joint
synarthrotic or amphiarthrotic
cartilaginous joint is a ___ joint
amphiarthrotic or synarthrotic
bony joint is a ___ joint
synarthrotic
how do extension and flexion work
plane=sagittal
axis of rotation = medio-lateral
how do adduction and abduction work
plane=frontal/coronal
axis of rotation=antero-posterior
how does rotation work
plane=transverse / horizontal
axis of rotation=vertical
name the 6 synovial joints
gliding
hinge
pivot
condylar
saddle
ball and socket
what planes of movement do gliding joints allow
none i.e non axial
what planes of movement do hinge joints allow
one (sagittal plane) i.e uniaxial
what planes of movement do pivot joints allow
one (vertical plane) i.e uniaxial
what planes of movement do condylar joints allow
two (coronal and sagittal) i.e biaxial
what planes of movement do saddle joints allow
two (coronal and sagittal) i.e biaxial
what planes of movement do ball and socket joints allow
three (sagittal, coronal and vertical) i.e mutiaxial
Outline the functions of muscles
- Motion: Walking, running, blood & urine (peristalsis), air (external respiration)
- Stabilising Body Position: Posture and alignment of the skeleton
- Regulation of Organ Volumes: Smooth muscles and sphincters
- Support of Soft Tissue: Protect and maintain position of organs (Pelvic)
- Maintain body temperature: Production of heat through contractions/shivering
- Storage nutrients: Amino acids (protein) and glycogen
identify types of muscle tissue
smooth skeletal and cardiac
describe organisation of cardiac muscle
-Muscle Fibres arranges as branched parallel bands that appear ‘Striated’
-One, central nucleus
-Involuntary Control; (Autorhythmic)
describe organisation of smooth muscle
-non striated
-one, central nucleus
-involuntary control
-Visceral ‘Single-unit’ Smooth Muscle Tissue or Multiunit Smooth Muscle Tissue (each unit has own nerve tissue eg arrestor pili)
describe organisation of skeletal muscle
-myocytes
-voluntary
-Long, cylindrical multinucleated cell –> striations
-Cannot divide, but satellite cells (stem cells) can repair/replace
-Muscle cell membrane = sarcolemma
-Muscle cell cytoplasm = sarcoplasm
what is found in a sarcoplasm
- Mitochondria
- Glycogen
- Myoglobin
- Transverse (T) Tubules
- Sarcoplasmic Reticulum (smooth ER)
identify layers of connective tissue in muscle from inside to out
- Endomysium
-Fascicle - Perimysium
-muscle
-Epimysium
-Tendons
Describe how muscles contract
-Nervous system sends electrical signal to muscle.
-Signal triggers release of calcium ions.
-Calcium ions bind to proteins in muscle fibers.
-Molecular events cause actin and myosin filaments to slide past each other.
-This sliding generates force and shortens muscle fibers.
-ATP provides energy for contraction.
Describe how muscles relax
-Nervous system signals relaxation by reducing stimulation.
-Calcium ions are pumped back into storage sites.
-Without calcium, proteins in muscle fibers change shape.
-Actin and myosin filaments return to their resting positions.
-Muscle fibers elongate, relaxing.
Explain how muscles work with tendons to move the body.
- The muscle tissue attaches its tendon at the Myotendinous Junction
- Tendons are long, whitish strap-like bands that transmits contractile force from muscle(s) to the location on bone
what’s a dermatome
Each sensory area on the skin
-arises from Doral root ganglion
what’s a myotome
muscle groups stimulated by afferent nerve
-arises from ventral root
what’s atrophy
Decrease Growth of Muscle Cell Size & Decreased strength/speed of myofibrils
what’s hypertrophy
increased Growth of Muscle Cell Size & Increased strength/speed of myofibrils
