Skeletal System
• Provides body with rigid framework of support and structure
• Bones are living organs. Can change and help body respond to changing environment
• Specialized cells allow bone to grow in size and shape as we grow
Functions• Support: supporting framework for body• Protection: skull protects brain, breastbone and ribs protect
vital organs (heart, lungs), vital tissue (red bone marrow- blood cell forming tissue
• Movement: muscles anchored to bone, contract and shorten, pull on bones and move
• Storage: Maintain homeostasis of blood Calcium (bones store extra calcium in blood, when blood calcium low, bone releases calcium (can lead to osteoporosis)
• Hemo (blood) poiesis (to make): blood cell formation in red marrow- found in spongy bone located in ends of long bones
Infant: (cartilage skeleton turns to bone as cartilage is replaced
with bone) . Increased red marrow turns into yellow marrow (inactive fatty tissue)
Microscopic structure of bone and cartilage
2 major types of Connective Tissue
• Bone
• Cartilage
BONE• Different appearance and texture depending on
location• Outer bone layer: (hard & dense) Dense or
Compact bone• Porous bone in end of long bones: Spongy bone
(contains many spaces that can be filled with marrow)
Trabeculae (in spongy bone- threads
surround network of spaces)( text 89)
Compact or Dense Bone• No network of open spaces• Matrix of Haversian Systems (multiple layers of
calcified matrix in rings called concentric lamella that surround Haversian canal which contains blood vessels
• Bone cells: osteocytes, found between hard layers of lamella, in little spaces called lacunae.
• Tiny passageways-canals: canaliculi connect lacunae with each other and the central canal in Haversian system
(text 90, 91, overheads A9, A10)
• Nutrients pass from blood vessels in
Haversian canal through canaliculi to osteocytes (in lacunae that are in concentric lamella)
• Many blood vessels from outer periosteum enter bone -> Haversian canals (with blood vessel)
Osteoclasts: bone absorbing cells allow bone tissue present to be absorbed/removed
Osteocytes and osteoclasts required for bones to grow and heal.
Osteoblasts: bone forming cells
Cartilage
• Like bone consists of intercellular substances and cells
• Collagenous fibers reinforce matrix of both tissues
In cartilage: fibers are embedded in firm gel matrix gives flexibility
In bone: hard, calcified matrix gives rigidity
Chondrocytes: cartilage cells (like osteocytes in bone) are located in lacunae, but lacunae suspended in cartilage (gel) matrix (compared to bones concentric lamella)
No blood vessels in cartilage.Nutrients must diffuse through matrix to reach cells
(text 92, A11) Study guide part 1
Structure of Long Bones• Diaphysis: (Shaft) Hollow tube made of hard compact
bone- rigid, strong, structure. Light weight, easy movement
• Medullary cavity: Hollow area inside diaphysis of bone contains soft yellow marrow (fatty)
• Epiphysis: Ends of bone where red marrow fills in small spaces in spongy bone (trabeculae) that composes epiphysis
• Articular cartilage: Thin layer of cartilage covering each epiphysis- functions like rubber cushion around joint
• Periosteum: Strong fibrous membrane covering long bone, except at joint surfaces (where it’s covered by articular cartilage)
(text 93, 94, overhead A9, A11)
Epiphyseal fracture
• Young children susceptible to fracture
• Epiphyseal plate (growth plate) can be separated from diaphysis or epiphysis.
• As soon as plate replaced with calcified matrix, growth is complete
(text 94, 95, overhead A11)
Bone formation and growth• Skeleton of baby before birth- cartilage & fibrous
structures shaped like bone• Transforms into bone when cartilage replaced with
calcified matrix deposited by osteoblasts, (bone forming cells)
• Combined action of : Bone forming osteoblasts and bone absorbing osteoclasts sculpts bone into adult shapes.• Laying down of calcium salts in matrix calcification
makes bones hard. (XS Ca from blood stored in bone, low Ca in blood, Ca removed from bone osteoporosis
• Vitamin D (made in dermis with UV exposure) aids is Ca absorption. (milk w/ vitamins A and D added)
(text 94, overhead A11)
Bone growth cont’d• Diaphysis: grows in both directions toward both epiphyses,
and both epiphysis grow toward diaphysis
• Continues until all epiphyseal cartilage has been transformed to bone
• IF epiphyseal cartilage still present, growth still occurring.
• If epiphyseal cartilage absent, adult growth attained.
• Ossification: cartilage undergoes ossification and becomes bone. Occurs in shaft of diaphysis and then in epiphyses.
(overhead A11) study guide part 2 and diagram 1 structure of human bone and diagram ws
Skeletal Lab with Chicken Bones
Types of bones
flat bone Thin bones that protect certain organs, including most
of the bones of the skull as well as the scapula.
short bone Bones shaped somewhat like cubes that facilitate flexibility of the joints; examples include the bones of the wrist and ankle.
long bone Elongated bone to which powerful muscles, such as those of the leg and arm, are attached.
irregular bone Bones of varying shapes and sizes, such as the vertebrae and certain bones of the skull or pelvis.
Divisions of Skeleton
• Axial: bones of skull, spine, chest, hyoid
• Appendicular: bones of upper extremities (shoulder, pectoral girdle, arms, wrists, hands), bones of lower extremities (hip, pelvic girdle, legs, ankles, feet).
(text 96, 97, overhead A12, A13 review parts/terms/location)
Interactive Drag and Drop. Simulations/Virtual surgeries
Articulated/Disarticulated Skeleton and joints
Axial Skeleton• SKULL: cranium (8 bones) face (14 bones) middle ear (6 bones)Sinuses: spaces/cavities inside some of cranial bones 4 pairs: frontal maxillary sphenoid ethmoid
Openings into nose referred to as paranasal sinuses
Inflammation of mucus membrane: swollen, painful frontal sinusitis
(text 102, 103, overheads A14, A15) study guide diagram 4 and 5
Mastoiditis• Inflammation of airspaces
within mastoid portion of
temporal bone from infection
of middle ear. • Mastoid cells don’t drain
into nose like paranasal sinuses.
• Infectious material may erode bony partition to brain and spread infection to covering membranes
(text 102, overhead A15)
Axial skeleton cont’d• SPINE: (Vertebral column)
Consists of series of separate bones (vertebrae),
connected to form flexible rod
7 cervical region
12 thoracic region
5 lumbar region
1 sacrum region
1 coccyx region
(text 104, overhead A16)
Axial skeleton cont’d• Vertebrae: spinous process
2 transverse processes
vertebral foramen (hole in center)• Tip head forward. Run finger down back of neck
to shoulder level. Feel tip of 7th cervical vertebra’s spinous process
• 7 cervical vertebrae form
supporting framework of
neck(text 104, 106, overhead A16)
Axial skeleton cont’d4 Curves of the spine: Neck and small of back curve slightly inward/forward Chest area of spine and lower lumbar curve opposite creating 4 curves• Cervical and lumbar curves: concave (in)• Thoracic and sacral: convex (out)Cervical: concave (in) developThoracic: convex (out) Lumbar: concave (in) developSacral: convex (out)(text 104, overhead A16)
Concave in
Convex out
Concave in
Convex out
Axial skeleton cont’dNewborn: continuous convex curve from top to
bottom. Gradually changes Holding head up: concave neck-cervical (in)
Stand up: concave lumbar (in)
Creates the 4 curves of the spineNormal curves important: Strength to support
body, balance to stand, walk on 2 feet.Curved structure has increased strength(text 104, overhead A16)
Axial skeleton cont’d• Poor posture/disease can cause curves to
become abnormally exaggerated• Swayback or Lordosis: lumbar curve
exaggerated
lumbar
Kyphosis or Huntchback: thoracic curve exaggerated
Scoliosis: abnormal side to side curvature(text 105)
Axial skeleton cont’d• THORAX or CHEST12 prs of ribsSternum (breastbone)Thoracic vertebrae
All form bony cage/protection• Each of 12 prs of ribs attaches posteriorly to a vertebra• All ribs except lower 2 prs attach to sternum giving them
anterior and posterior anchorage• Prs 1-7 true ribs: attach to sternum by costal cartilage• Prs 8, 9, 10 false ribs: attach to cartilage of 7th • Prs 11, 12 floating ribs: don’t attach to any costal cartilage
(text 104, overhead A16)
Appendicular Skeleton
• 126 of 206 bones appendicular
• Bones in shoulder & pectoral girdle attach the bones of arm, forearm, wrist and hands to axial skeleton of thorax
• Bones in hip and pelvic girdle attach the bones of thigh, leg, ankle and feet to axial skeleton of pelvis
Upper Extremity Pectoral girdle
• Scapula (shoulder blade) and clavicle (collar bone) compose
shoulder (pectoral girdle) which functions to attach upper extremity to axial skeleton (in thorax)
Sternoclavicular joint: Only direct point of attachment between clavicle & sternum (breastbone)- very small attachment- provides wide range of motion but susceptible to injury b/c ↑ pressure can occur at joint
(text 96, 97, overheads A12, A13)
Upper Extremity cont’d• Humerus: long bone of arm, 2nd longest in body• Attaches to scapula at its proximal end and
articulates with 2 bones of forearm, the radius (thumb side) and ulna
• Elbow: Ex of structure that determines function• Long bony process of ulna (olecranon
process), fits into large depression on posterior surface of humerus (olecranon fossa) makes joint movement
• Radius and ulna of forearm articulate with each other and distal end of humerus at elbow joint.
• Radius and ulna touch each other distally for articulation with wrist bones
(text 106, 107 overhead A17)
Upper Extremity cont’d• Anatomical position: ulna medial (inside)
radius lateral (outside-thumbside)
Wrist and hands: many bones• 8 carpal (wrist bones) (vs 7 tarsals/ankle)• 5 metacarpal (form support structure for palm)• 14 phalanges (finger bones) (distal, middle, proximal)
27 total many bones, joints,
= increased dexterity
but more bones to break
(text 108, 109, overheads A18)
Lower Extremity• Hip (pelvic girdle) attaches legs to trunk• Consists of 2 large innominate bones, 1 located on
each side of pelvis• 2 innominate bones, sacrum, coccyx: provides strong
base of support for torso- serves to attach lower extremities to axial skeleton
• Infant: Innominate bone consists of 3 bones: ilium, ischium and pubis
that grow to become 1 innominate bone in adult (text 119 review parts/location)
Lower Extremity cont’d• Femur: thigh bone, longest bone in body • articulates proximally (toward hip) with innominate bone
in deep cup shaped socket (acetabulum) • Articulation of acetabulum more stable than articulation
of head of humerus with scapula in upper extremity• Hip dislocation less common than shoulder• Distally, femur articulates with knee cap (patella) and
tibia (shin bone). • Fibula: slender outer (lateral) border of lower leg
(text 112, 113, overhead A17)
Lower Extremity cont’d• Toe bones: (phalanges) same # (14) as finger bones:
(proximal, middle, distal)• Foot bones: 5 metatarsals (similar to hand/palm metacarpals) and
7 tarsals (vs 8 carpals in hand)• Feet: standing features for support• Big toe: more solid vs thumb, but less mobile• Foot bones, held together to form springy arches increase support, strength stable base
Fallen arches: (flat feet) foot ligaments/tendons weaken
3 arches: medial longitudinal arch (inside)
lateral longitudinal arch (outer edge)
transverse or metatarsal arch (extends across
ball of foot) (text 114, 118, overheads A19) study guide part 3 and diagram 2 and 3
axial/appendicular diagram ws LAB
Male vs Female Skeleton• Size: male skeleton larger vs female (no functional importance)• Hip bone structural differences: (functional importance)• Female pelvis made so baby can be cradled before birth
and pass through at birh• Male: Innominate (hip) bones larger and narrower
Funnel Shaped • Female: pelvis broader, shallow basin shape, and pelvic
inlet wider(text 119 review parts, location) study guide part 4 and with pgs 115-117 part 5
Male vs Female Pelvis ActivityBone Development and Osteoporosis worksheetSports Injuries worksheet
Osteoporosis• Osteoporosis: bone disease characterized by xs loss of
calcified matrix and collagenous fibers from bone.• (xs calcium stored in bone, when calcium levels low,
calcium removed from bone leaves bones brittle, degeneration increased fractures and curvature of spine
• Sex hormones important role in stimulating osteoblast activity after puberty. Decreased hormone levels in elderly reduces new bone growth and maintenance.
• Treat with hormone therapy, dietary supplements (calcium and vitamin D to help absorb calcium.
***Dermis cells exposed to UV rays make vitamin D (remember) to help absorption of calcium also vitamins A and D added to milk! Drink your milk!
Joint Articulations• Every bone in body connects to another bone via joints-
except hyoid bone in neck (tongue attaches to)• Joints perform 2 functions: 1. Holds bones together securely 2. Makes movement possible between bonesType of joint determines type and range of movement
3 kinds of joints based on degree of movement 1. Synarthroses 2. Amphiarthroses 3. Diarthroses(text 120, 121 overheads A20 and binder)
Types of Joints cont’d• Synarthroses: joint where fibrous connective tissue grows
between articulating (joining) bones, holding
them close together sutures Ex. Cranial
bones
Types of Joints cont’d• Amphiarthroses: joint where cartilage connects articulating bones Ex. Symphysis pubis (joint between pubic bones) joints between bodies of vertebrae
Allows flexing of trunk forward, sideways, circumduct (rotate)
Strong ligaments connect bodies of vertebrae & fibrous disks lay between them
Central core of invertebral disks pulpy/elastic- ↓ resiliency w age
Can be compressed by sudden exertion/injury w/ fragments protruding into spinal canal- pressing on nerve root of spinal cordsevere pain herniated/slipped disk
(text 120, 121, 122 overhead A20 and binder)
Types of Joints cont’d• Diarthroses: most joints, allow considerable movement in 1, 2 or many directions.
Structure of Diarthroses joints: All have joint capsule, joint
cavity, and layer of cartilage over ends of 2 adjoining bones(text 122, overhead A21 and binder)
Display joints and skeleton
Structure of Diarthroses joints cont’d
• Joint capsule: made of strong fibrous connective tissue, lined with smooth, slippery synovial membrane capsule fits over ends of 2 bones like sleeve Joint capsule attaches firmly to shaft to form covering (periosteum) around bone. It holds bones together securely, but permits movement at joint
Structure of joint capsule helps make possible joint function
(text 122, overhead A21 and binder)
Structure of Diarthroses joints cont’d
• Ligament: cords or bands made of same strong connective
tissue as joint capsule grow out of periosteum &
connect bone to bone firmly
• Articular cartilage layer: over joint ends, acts like rubber
cushion- absorbs jolts
• Synovial Membrane: Secretes lubricating synovial fluid, allows
easier movement, ↓ friction
(text 122, overhead A21 and binder) study guide diagram 6
Types of Diarthroses Joints• Ball and Socket• Hinge• Pivot• Saddle• Others
Differences in structure
differences in type and range of motion
(text 122, overhead A21 and binder)
Types of Diarthroses Joints• Ball and Socket: ball shaped head of 1 bone fits into concave
socket of another. Permit widest range of motion
Ex. Shoulder and hipForward (text 121, overheads A20 and binder)
Backward
Abduct (away from side)
Adduct (towards side)
Circuduct (@ in circle)
Types of Diarthroses Joints cont’d
• Hinge Joints: Allows movement in 2 directions (door)
Flexion (bending)
Extension (straightening)
Ex. Elbow, knee, fingers
Pivot Joints: Small projection of bone pivots in arch of another bone
Ex. Projection of axis (C2) pivots in arch of atlas (C1) rotates head that rests on atlas
(text 121, overheads A20 and binder)
Types of Diarthroses Joints cont’d
Types of Diarthroses Joints cont’d
Gliding Joint: opposed surfaces are flat or only slightly curved,
so that the bones slide against each other in a
simple and limited way.
bones of the wrist and ankle meet in gliding joints
gliding movement.
Types of Diarthroses Joints cont’d• Saddle Joints: only 1 pr between metacarpal (of thumb) and carpal (trapezium) of wrist
Articulating surfaces of these bones- saddle shaped, allow thumb great range of
movement
mobility/dexterity: flex, extend, abduct, adduct, circumductWithout saddle joint- No grasping, picking up, or holding utensil
(text 121, overheads A20 and binder) study guide part 6, 7, 8 and 9 Diarthroses- synovial joint ws M&L study guide
Skeletal System
You should have the following completed
• Study guide including all diagrams
• Lab
• All worksheets, diagrams and additional study guide(s)
• End of chapter test