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