What are the 5 functions of the skeletal system?
Support - the skeletal system provides structural support for the entire body.
Bones provide attachments for soft tissues and organs
Storage - stores calcium salts for body fluids
Lipids are stored in yellow marrow for energy reserves
Blood cell production - happens in the red marrow: red blood cells, white blood cells, and platelets.
Protection - protects soft tissue and organs that it surrounds.
Ex. skull protecting brain, ribs protecting heart.
Movement - bones function as levers. Muscle pulls on bone to initiate movement.
What 2 factors aid in classifying bones?
Macroscopic - general and visible features of the bones
ex) compact bone, spongy bone, marrow cavity
Microscopic - features of the bone not visible to the human eye
ex) osteocytes, osteoclasts, osteoblasts
What are the 4 shapes of bones (know examples of each)?
Long
Longer than wide
Ex: humerus
Short
Wider than long
Ex: carpal bones
Flat
Broad
Ex: scapula
Irregular
Complex
Ex: vertebrae
Identify these parts of the long bone: epiphysis (proximal and distal), diaphysis, articular cartilage, spongy bone, compact bone, marrow cavity, endosteum, periosteum, epiphyseal line.
Epiphysis = wider portions at each end
Proximal = round
Distal = looks like a heart
Diaphysis = central shaft
Articular Cartilage = covers the epiphyses
Spongy Bone = aka cancellous bone, projections of bone separated by space like a sponge, found in epiphyses
Compact Bone = densely packed, forms the diaphysis
Marrow Cavity = bone marrow filling found in the diaphysis
Endosteum = lines the marrow cavity and spongy bone
Periosteum = the outer covering of bone
Epiphyseal Line = aka growth plate, a cartilaginous plate located in the epiphyses
Identify these microscopic terms: osteocytes, osteoclasts, osteons, osteoblasts, lacunae, lamellae, canaliculi, trabeculae, ossification, calcification.
Osteocytes:
Bone cells
Mature cells that maintain bone structure
Osteoclasts
Large cells that secrete acid and enzymes
50+ nuclei
Osteons
Basic functional unit of compact bone
Osteoblasts:
Help produce new bone
Lacunae
Packers in the osteocytes
Lamellae
Found between the sheets of the matrix in osteocytes
Canaliculi
Small channels that connect the lacunae and other blood vessels and run through the matrix
Trabeculae
Rods or plates that create an open network
Arrangement of spongy bone
Ossification
Producing new bone
Calcification
Calcium builds up in body tissue
Hardening the tissue
Differentiate between intramembranous ossification and endochondral ossification
Intramembranous ossification
Occurs during fetal development
Osteoblasts develop calcified matrix
Ossification happens (starting at the ossification center)
New bone created and develops body supply
Ex: spongy bones remodel into compact flat bones
Endochondral ossification
Embryonic cartilaginous skeletal structures replaced by true bone
Chondrocytes enlarge and matrix begins to calcify
Causing chondrocytes to die as they are closed off from nutrients
Bones start forming at the shaft surface
Osteoblasts produce bone matrix
Blood vessels invade the inner region of cartilage
New osteoblasts form spongy bone
Osteoclasts break down spongy bone
Forming marrow cavity
Epiphyseal cartilage continue to to enlarge
Center of the epiphyses calcifies
What are the 3 things that bone growth and development need to be in balance?
Osteoblasts → form osteons
Osteoclasts → destroy osteons
Osteocytes → maintain the bone matrix
What two items maintain the bone matrix?
Osteocytes in lacunae
Textbook doesn’t say another item - must find
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What is the turnover rate for bone?
The turnover rate for bone is quite high, and in young adults almost ⅕ of the skeleton is recycled and replaced each year.
Is every part of the bone remodeled? Explain.
Not every part of every bone is affected; regional and even local differences in the rate of turnover occur.
For example, the spongy bone in the head of the femur may be replaced 2 or 3 times each year, whereas the compact bone remains largely untouched.
What allows each bone the ability to adapt to new stresses?
Regular mineral turnover (bone remodeling) gives each bone the ability to adapt to new stresses.
If a bone is heavily stressed, what happens to it?
Heavily stressed bones become thicker and stronger and develop more pronounced surface ridges.
What happens to a bone if it is not subjected to ordinary stresses?
Bones not subjected to ordinary stresses become thin and brittle.
Degenerative changes occur after even brief periods of inactivity.
What does regular exercise do for bones?
Regular exercise is an important stimulus in maintaining normal bone structure.
Explain what happens to the leg bone in a cast requiring a crutch during and after recovery.
When using a crutch the weight is taken off the injured leg, so the bone will become thinner and more brittle. After a few weeks, the unstressed leg will lose ⅓ of its bone mass. The bones rebuild just as quickly once they again carry their normal weight.
What is the most abundant mineral in the human body?
Calcium
Explain what happens in the body to certain physiological processes if calcium ion concentrations increase and if they decrease.
Calcium levels must be very carefully controlled as they play an important role in many physiological processes.
Even small variations from the normal concentration affect cellular operations, and larger changes can cause a clinical crisis.
Neurons and muscle cells are particularly sensitive to changes in calcium ion concentrations.
If the calcium concentration in body fluids increases by 30%, neurons and muscle cells become unresponsive.
If calcium levels decrease by 35%, they become so excitable that convulsions may occur.
If calcium levels decrease by 50%, death occurs.
However, our bodies closely regulate our calcium concentrations so that levels usually don’t fluctuate more than 10%.
How can calcium levels in body fluids become elevated?
The hormones Parathyroid Hormone (PTH) from the parathyroid glands and calcitriol from the kidneys work together to elevate calcium levels in body fluids.
Their opp is calcitonin, a hormone from the thyroid gland that depresses calcium levels.
What are 3 main causes of bone fractures mentioned in the text?
Extreme loads
Sudden impacts
Stresses from unusual directions
In order for bones to heal on their own, what do they need?
Bones usually heal on their own so long as blood supply remains and the cellular components of the endosteum and periosteum survive.
How long can the bone repair process take?
The repair process can take from 4 months to well over a year.
Explain the 4 steps in the repair of a fracture.
Extensive bleeding
Large blood clot → hematoma forms
Internal callus forms
Spongy bones unite the inner edges
External callus of cartilage and bone stabilize the outer edges
External callus is replaced by bone
Swollen area at fracture site
Overtime the site will be remodeled
Explain what happens to bones as we age.
Osteopenia
Inadequate ossification that naturally occurs when aging (30-40)
Osteoblastic activity begins to slow down
Osteoporosis
Loss of bone mass that impairs normal functions and can lead to more fractures
Why is osteoporosis more common in older women than in older men?
More common in women due to decline is circulating estrogen after menopause
Where do elevations and projections form on bones and what are they used for?
Tendons and ligaments where adjacent bones articulate at joints
Define/Identify these terms: process, trochanter, tuberosity, tubercle, spine, head, neck, condyle (median and lateral), trochlea, crest, foramen, canal, fissure, sinus
Process = any projection or bump
Trochanter = a large, rough projection
Tuberosity = a smaller, rough projection
Tubercle = a small, rounded projection
Spine = a pointed process
Head = the expanded articular end of an epiphysis, separated from the shaft by a neck
Neck = a narrow connection between the epiphysis and the diaphysis
Condyle = a smooth, rounded articular process
Trochlea = a smooth, grooved articular process shaped like a pulley
Crest = not described
Foramen = a rounded passageway for blood vessels or nerves
Canal = a duct or channel
Fissure = an elongated cleft or slit
Sinus = a chamber within a bone, normally filled with air
What are the two skeletal divisions and their subdivisions?
Appendicular 126 appendicular bones 32 in the upper limb 31 in lower limb Axial 22 bones of the skill with 7 associated bones 6 auditory and hyoid Thoracic cage Composed of 24 ribs and sternum 26 bones of the vertebral column
Define/Identify these fractures: partial, complete, open, closed, non-displaced, displaced, transverse, oblique, greenstick, impacted, comminuted, segmental
Partial
Break that does not go through the bone completely
Complete
Fracture in which the bone goes through the skin and can be seen through the surface
Closed
(known as simple fracture)
Bone that does not break
Non-displaced
Break in which the two ends are lined up and not moves out of place
Displaced
Break in which two ends are NOT lined up and are moved out of place
Transverse
Break that occurs in a straight line
Oblique
Break that occurs in a diagonal
Greenstick
Partial fracture that occurs bones to break (in children)
Impacted
Broken ends of bone that are jammed together by the force of injury
Comminuted
Bone is broken in at least three different places with many fragments at the site
Segmental
Bone is broken into two places ; floating segment between the two bones
Be able to identify these bones: phalanges, tarsals, metatarsals, carpals, metacarpals, tibia, fibula, patella, femur, pelvis, coccyx, sacrum, sternum (manubrium, body, xiphoid process), lumbar vertebrae, thoracic vertebrae, cervical vertebrae, ribs, scapula, clavicle, humerus, radius, ulna, mandible, skull.
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What are the functional classifications of joints?
Synarthrosis (immovable)
Amphiarthrosis (slightly movable)
Diarthrosis (freely movable)
What are the structural classifications of joints?
Fibrous and Cartilaginous
Limited movement
synovial
Freely moveable
What are the 6 types of synovial joints?
Gliding
Flat or slightly curved surfaces
Movement is slight
Hinge
Permit angular movement in one plane
Ex: closing and opening a door
Pivot
Allows for rotation only
Ex: turning the head ; supinating or pronating the palm
Condylar
Allows angular motion in two planes
Saddle
Allows for circumduction ; not rotation
Ball and socket
What are/is synovial fluid? Menisci? Fat Pads? Bursae?
Synovial fluid
Helps reduce friction
Menisci
Additional synovial joint padding
Fat pads
Cushions for joints
Bursae
Packets of connective tissue that contain synovial fluid
Reduce friction and absorb shock
Be able to identify the types of joint movement (either by description or picture…use your folder!)
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Axial or Appendicular?
After the bone name, indicate if it falls into the axial or appendicular skeleton. Practice spelling here!
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Mandible:
axial
Tibia:
appendicular
Thoracic Vertebrae:
axial
Carpal:
appendicular
Ulna:
appendicular
Scapula:
appendicular
Manubrium:
axial
Femur:
appendicular
Humerus:
appendicular
Phalanges:
appendicular
Cranium:
axial
Sacrum:
axial
Cervical Vertebrae:
axial
Ribs:
axial
Clavicle:
appendicular
Metacarpals:
appendicular
Radius:
appendicular
Fibula:
appendicular
Xiphoid Process:
axial
Pelvis:
appendicular
Metatarsals:
appendicular
Lumbar Vertebrae:
axial
Coccyx:
axial
Patella:
appendicular
Hyoid:
axial
List the three structural classifications of joints.
Fibrous - Limited movement
Cartilaginous - Limited movement
Synovial - Freely moveable
What are the three functional classifications of joints?
Synarthrosis - Immovable
Amphiarthrosis - Slightly movable
Diarthrosis - Freely movable
List the 6 types of “freely movable” joints and give an example of each. Include an individual (not a group) image of each one listed.
Gliding joints → have flattened or slightly curved faces, slide across one another
Hinge joints → permit angular movement in a single plane, like a door
Pivot joints → rotation only
Condylar joints → aka ellipsoid joints, oval articular face nestles within a depression on the opposing surface
Saddle joints → have articular faces that fit together like a rider in a saddle, each face is concave on one side and convex on the other, permits angular movement and circumduction
Ball-and-Socket joints → the round head of one bone rests within the cup-shaped depression of another bone, all combinations of movements are possible
Explain the following terms in your own words. Include an individual image with each
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Abduction of leg
leg is going away from the body
Adduction of leg -
leg is going towards the body
Flexion of arm -
front double bicep flex
Extension of arm -
not bending your arm
Depression of shoulder -
putting ur shoulder down
Elevation of shoulder -
raising your shoulders up
Inversion of foot -
foot is pointed towards the opposite foot
Eversion of foot -
foot is pointed away from the opposite foot
Plantar flexion of foot -
toes are facing down ; raising the heels up
Dorsiflexion of foot - \n
lift toes up ; rocking back on the heel
10. Pronation of hand \n
- palm faces ground → palm faces face
11. Supination of hand - \n
palm faces face → palm faces ground
Touching your Toes from an Upright position (Upright, touch, then return Upright; Assume you are completely flexible and this is NOT a struggle)
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