What are the 6 components of the skeletal system?
- Bones 2. Joints 3. Tendons 4. Ligaments 5. Cartilage 6. Teeth
Functions of the skeletal system?
- Provides shape and form for our bodies 2. Protects vital organs 3. Body movement by attachment to muscles 4. Produces blood cells (bone marrow) 5. Mineral storage area
2 minerals stored in the bone?
Calcium and phosphate
How many bones in the adult human body?
206
More or less bones in children?
More
What are the 2 parts of the skeletal system? Describe each.
- Axial: bones that support and protect the organs of the head, neck, and trunk
- Appendicular: bones that anchor appendages to the axial skeleton
List the 4 parts of the axial skeleton.
- Skull 2. Sternum 3. Ribs 4. Vertebral column
List the parts of the appendicular skeleton.
- Upper limbs 2. Lower limbs 3. Shoulder girdle 4. Pelvic girdle
What are bones?
Organ-calcified, living, connective tissue
3 types of cells in bone? What does each do?
- Osteoblasts: form bone 2. Osteoclasts: resorb or break down bone 3. Osteocytes: mature bone cells
What are the 3 constituents of bone?
- Intercellular calcified matrix 2. Collagen fibers 3. Several cell types
What causes an osteoblast to mature into an osteocyte?
When it has formed all of the bone it could
How does the number of osteocytes in our bones change as we age?
Increases
How does the number of osteoblasts in our bones change as we age?
Decreases
What 2 hormones regulate the blood concentration of calcium? How do they work?
- Calcitonin: activate osteoblasts 2. Parathyroid: activate osteoclasts
What bone cell type does growth hormone affect?
Activates osteoblasts
What bone cell type does estrogen affect?
Inhibits osteoclasts
What bone issue does menopause cause?
Osteoporosis (loss of bone density) because osteoclasts are no longer inhibited by estrogen
Describe the outside vs inside of bones?
Outside: dense - little to no space between matrix and cells Inside: less dense
What 4 hormones affect bone cells?
- Calcitonin 2. Parathyroid 3. Growth hormone 4. Estrogen
What are the 2 bone types?
- Compact 2. Spongy
Describe compact bone.
Outer shell of all of the bones that is more dense
% weight of bone formed by compact bone?
80%
Function of compact bone?
Bone strength and rigidity
Describe spongy bone.
Less dense and consists of spicules of bone enclosing cavities containing blood-forming cells
What are bones classified by?
- Shape 2. Compact/Spongy content
Do most bones contain both compact and spongy bone types?
YUP
2 functions of spongy bone?
- Lighter to allow for movement 2. Space for bone marrow
Which skeleton has more compact bone?
Axial
Which skeleton has more spongy bone?
Appendicular
2 bones of the head?
- Cranium 2. Mandible
3 bones of the upper limbs?
- Humerus 2. Radius 3. Ulna
3 bones of the hands?
- Carpals (wrists) 2. Metacarpals (palm) 3. Phalanges (fingers)
2 bones of shoulder girdle?
- Clavicle (collar bone) 2. Scapula (shoulder blade)
2 bones of the trunk?
- Sternum 2. Ribs
4 bones of the lower limbs?
- Femur 2. Patella 3. Tibia 4. Fibula
In the leg which bone is more medial: tibia or fibula?
Tibia
3 bones of feet?
- Tarsals (ankle) 2. Metatarsals (foot) 3. Phalanges (toes)
3 bones of pelvis? Describe their location.
- Ilium: most superior bone 2. Pubis: inferior and anterior 3. Ischium: inferior and posterior
Are the 3 bones of the pelvis separate bones?
NOPE - they fuse in adults
What is the bone of the bottom segment of the vertebra?
Sacrum
What does the sacrum attach to?
Pelvic bones
What bone attaches inferior to the sacrum? 2 names
Tail bone = coccyx
Biggest and heaviest long bone of body?
Femur
Which bone attaches to humerus superiorly?
Scapula
At what part does the clavicle attach to the scapula?
Acromion
Which is the largest bone of the pelvis?
Ilium
Describe long bones.
- Longer than they are wide 2. Long shaft with 2 bulky ends 3. Primarily compact bone and with some spongy in bulky ends
List 9 long bones.
- Clavicle 2. Humerus 3. Radius 4. Ulna 5. Femur 6. Tibia 7. Fibula 8. Metacarpals 9. Phalanges
Describe short bones.
- Cuboidal-vertical and horizontal dimensions are roughly equal 2. Primarily spongy bone with a thin outer layer of compact bone
List 2 short bones.
- Carpals 2. Tarsals
What are the types of bone?
- Long bones 2. Short bones 3. Flat bones 4. Irregular bones 5. Sesamoid bones
Describe flat bones.
- Thin, flat sheets 2. Two compact bone plates separated by spongy bone
List 4 flat bones.
- Skull 2. Ribs 3. Sternum 4. Scapula
Describe irregular bones.
- Bones that don’t fit in other 3 categories 2. Usually spongy bone covered in small compact sheath
List 3 irregular bones.
- Face 2. Vertebra 3. Pelvis
Describe sesamoid bones.
- Round or oval 2. Found in locations where a tendon passes over a joint
List 3 places where sesamoid bones are found?
- Hand 2. Knee 3. Foot
What kind of bone if the patella?
Sesamoid bone
Function of sesamoid bones?
Protect the tendon and joint and increase its mechanical effect
Do bones have pain receptors?
NOPE
Where does pain come from when we break a bone?
Periosteum rupture or pull
What is the periosteum?
Highly innervated and vascularized membrane that covers all of the bones
Role of periosteum when bone is fractured?
Brings blood, cells, and nutrients to fix the fracture
Describe cartilage.
Not as strong as bone but not as elastic as muscle
Functions of cartilage?
- Supports soft tissues 2. Provides a smooth, gliding surface for bone articulations at joints 3. Enable the development and growth of long bones
Where does bone growth happen?
Area between cartilage and bone
What does cartilage consists of?
Extracellular fibers embedded in a matrix
What does the amount of kind of extracellular fibers in the cartilage matrix depend on?
The type of cartilage
What kind of cartilage is found in synovial joints?
Hyaline cartilage
Describe the cartilage found in weight-bearing areas.
Inextensible with increased amount of collagen
Describe the cartilage found in areas of less stress.
Contains elastic fibers and fewer collagen fibers
What is a joint?
Site where two skeletal elements come together
What are 2 types of joints?
- Skeletal elements separated by a cavity
- Skeletal elements held together by connective tissue
What are examples of joints that do not move?
- Pelvic joints 2. Facial joints 3. Teeth 4. Skull joints
What do synovial joints contain? Purpose of each?
- Synovial membrane: produces synovial fluid 2. Synovial fluid: lubricates the joint and acts as a shock absorber
What covers the end of each bone in a synovial joint? Purpose?
Hyaline cartilage to reduce friction and act as a shock absorber
Where is the synovial membrane found in a synovial joint?
Attaches where bone and cartilage meet on each bone and then passes in between the 2 bones
What protects the synovial membrane in a synovial joint?
- Fibrous joint capsule 2. Ligament (optional)
What does a ligament do?
Joins bone to bone
What does a tendon do?
Joins muscle to bone to enable movement
What are synovial joints?
Connections between skeletal components separated by a narrow articular cavity
What are synovial joints categorized by?
- Shape 2. Movement
What are the 6 types of synovial joints based on shape?
- Plane
- Hinge
- Pivotal
- Ellipsoidal
- Saddle
- Ball and socket
What are the 3 types of synovial joints based on movement?
- Uniaxial 2. Biaxial 3. Multi-axial
Describe plane joints.
Non-axial joints that allow the sliding or gliding movements when one bone moves across the surface of another (both surfaces are flat)
List 7 plane joints.
- Acromioclavicular 2. Tibiofibular 3. Intertarsal 4. Intercarpal 5. Intermetacarpal 6. Carpometacarpal 7. Sternoclavicular
Describe hinge joints.
Uniaxial joint that allow movement around one axis that passes transversely through the joint
What 2 movements do hinge joints allow?
- Flexion 2. Extension
List 3 hinge joints.
- Humeroular joint (elbow) 2. Ankle (between tibia and tarsals) 3. Interphalangeal
Describe pivotal joints.
Uniaxial joint that allows movement around one axis that passes longitudinally along the shaft of the bone
What is another name for pivotal joints?
Trochoid joints
What movement do pivotal joints allow?
Rotation
List 3 pivotal joints.
- Atlanto-axial joint 2. Superior and inferior radioulnar joints
Where is the atlanto-axial joint?
Between first 2 vertebrae
Describe ellipsoidal joints.
Distinct convex surfaces articulate with concave surfaces and allow movement around two axes that are at right angles to each other (biaxial)
What 5 movements do ellipsoidal joints allow?
- Flexion 2. Extension 3. Abduction 4. Adduction 5. Circumduction (limited)
List 4 ellipsoidal joints.
- Wrist (radiocarpal)
- Atlanto-occipital
- Metacarpophalangeal joints
- Femur and tibia
Describe saddle joints.
The articular surfaces are saddle shaped (reciprocally concavoconvex) Allow movement around two axes (biaxial) that are at right angles to each other
What 5 movements do saddle joints allow?
- Flexion 2. Extension 3. Abduction 4. Adduction 5. Circumduction
List 2 saddle joints.
- Carpometacarpal joint of the thumb 2. Femur and patella
Describe ball and socket joints.
Allow movement around multiple axes (multiaxial)
What 6 movements do ball and socket joints allow?
- Flexion 2. Extension 3. Abduction 4. Adduction 5. Circumduction 6. Rotation
List 2 ball and socket joints.
- Hip joint 2. Shoulder joint
Which synovial joints are most unstable and easily injured?
Ball and socket joints
Describe solid joints. 2 types? How do they move?
Connections between skeletal elements where the adjacent surfaces are linked together either
- Fibrous connective tissue
or by
- Cartilage
Movement of these joints is usually restricted
Describe fibrous joints.
Connections between skeletal elements where the adjacent surfaces are linked together fibrous connective tissue
What is another name for fibrous joints?
Synarthroses
3 types of fibrous joints?
- Sutures 2. Gomphoses 3. Syndesmoses
Where are sutures found?
Between bones of the skull
Describe sutures.
Adjacent bones are linked by a thin layer of connective tissue: the sutural ligament
Describe gomphoses. What do we call these?
Occurs between teeth and adjacent bone and made of short collagen tissue fibers that run between the root of the tooth and the bony socket “peg and socket” joints
Describe syndesmoses.
Two adjacent bones linked by a ligament
3 examples of syndesmoses?
- Radius and ulna 2. Tibia and fibula 3. Ligamentum flavum (connects adjacent vertebral laminae)
What are cartilaginous joints?
Type of solid joint that connect skeletal elements by cartilage
2 types of cartilaginous joints?
- Synchondroses 2. Symphyses
2 examples of synchondroses?
- Ribs and sternum 2. Head and shaft of developing long bones
Describe synchondroses.
Two ossification centers in a developing bone remain and are separated by a layer of cartilage
Describe symphyses.
Ossified centers are interconnected via cartilage
Where do symphyses usually occur?
In the midline
2 examples of symphyses?
- Pubic symphysis 2. Intervertebral discs
Other name for synchondroses?
Primary cartilaginous joints
Other name for symphysis?
Secondary cartilaginous joints
What happens to the pelvic bone of pregnant women?
Cartilage dissolves overtime so there is no anterior connection to the pelvic bones to allow for child birth
Label.
What is a condyloid joint?
Ellipsoidal
Do ellipsoid and saddle joints have the same range of motion?
YUP
What is the atlanto occipital joint?
Joint between skull and 1st vertebra
