Lab 7

Articulation joint functions

1. holds bones together

2. allows skeletal system flexibility

Structural classes of articulations

1. Fibrous joints

2. cartilaginous joints

3. synovial joints

Fibrous joints

Mostly synarthrotic: no movement

• joined by fibrous tissue

2 major types of fibrous tissue

1. Sutures: interlock bones

2. Syndesmoses: articulating bones connected by short ligaments

Syndesmosis

1. Tibia

2. Fibula

3. Dense fibrous connective tissue

Cartilaginous Joints

Mostly amphiarthrotic: slight movement

• articulating bone connected by cartilage plate or pad

2 major types of Cartilaginous Joints

1. Symphyses: bones connected y broad, flat fibrocartilage disc

2. Synchondroses: bony portions united by hyaline cartilage

Synchondrosis

1. Sternum

2. First rib

3. hyaline cartilage

Symphyses

1. Body of vertebrae

2. fibrocartilaginous intervertebral disc

Symphysis

1. Pubis

2. Fibrocartilage

Cartilaginous epiphyseal plates

Synovial Joints

All diarthroses: free movement

• articulating bone ends separated by joint cavity filled with synovial fluid

Structural Features of Synovial Joints

1. articular capsule: enclose joint surface; reinforced by ligaments; may contain bursae(fluid sacs); may contain fibrocartilage pads(articular disc)

2. Synovial membrane: inner smooth connective tissue that produces fluid

3. Fibrous capsule: outer later of dense irregular connective tissue

4. articular (hyaline) cartilage: covers bone ends at joint

5. Joint cavity: encompassed by articular cartilage and synovial membrane, filled with synovial fluid

A. Multaxial synovial joint

1. Scapula

2. Hyaline cartilage

3. Humerus

B. Uniaxial synovial joint

4. Humerus

5. Hyaline cartilage

6. radius

7. ulna

C. Biaxial synovial joint

8. Radius

9. hyaline cartilage

10. Scaphoid

11. Ulna

12. Lunate

13. Triquetrum

1. Joint cavity (contains synovial fluid)

2. articular(hyaline) cartilage

3. fibrous layer

4. Synovial membrane (secretes synovial fluid)

5. Articular capsule

6 Types of synovial joints

The six types of synovial joints include ball-and-socket, hinge, pivot, condyloid, saddle, and plane joints, each allowing different ranges of motion.

Plane joints

lat surface (intercarpal/tarsal joints & vertebrocostal joints of ribs 2-7)

Hinge Joints

round end to concave surface

(elbow & interphalangeal joints)

Pivot Joints

round/conical bone to shallow depression/foramen (atlas & axis)

Condyloid Joint

oval condyle to ellipsoidal depression

(radiocarpal joint & metacarpophalangeal joints)

Saddle Joint

saddle shaped, one convex, one concave (metacarpal & trapezium of wrist)

Ball and socket

ball-shaped head fits into cuplike depression

Plane Joint (biaxial)

Hinge Joint (uniaxial)

Pivot Joint (uniaxial)

Condylar Joint (biaxial)

Saddle Joint (biaxial)

Ball and Socket joint (multi axial)

Body Movements

can occur during contraction of muscle attached to bones. Inserted muscles move bone toward muscle origin

Flexion

decrease joint angle

Extension

Increase joint angle

Hyperextension

increase joint angle over 180 degrees

Abduction

move limbs away from midline

Adduction

Move limbs toward midline

1. Muscle contracting

2. Orgin

3. Brachialis

4. Tendon

5. Insertion

1. Hyperextension

2. Extension

3. Flexion

4. Hyperextension

5. Extension

6. Flexion

1. Flexion

2. Flexion

3. Extension

4. Extension

5. Hyper extension

1. Abduction

2. Adduction

3. Circumduction

4. Rotation

5. Lateral roation

6. Medial rotation

Rotation

movement around longitudinal axis

Circumduction

distal end moves in circle

Pronation

palm from anterior to posterior

Supination

palm from posterior to anterior

Plantar Movements

1. Inversion: medial turn. of sole

2. Eversion: lateral turn of sole

3. Dorsiflexion: ankle joint dorsal movement

4. Plantar flexion: ankle joint flex downward

1. Pronation (radius rotates over ulna

2. Supination (radium and ulna are parallel)

3. P

4. S

5. Dorsiflexion

6. Plantar flexion

7. Inversion

8. Eversion

Muscle Cells

composed of multi-nucleated cells (known as muscle fibers)

• consist of myofibrils

Myofibrils consist of

Myofilaments - composed of contractile protein subunits

• actin: forms the thin filaments, anchored by Z disc

• myosin: forms think filaments, anchored by m line

1. Fiber

2. Nucleus

3. Sarcolemma

4. Nucleus

5. Myofibril

6. Thin(actin) filament

7. Thick(myosin) filament

8. Z disc

9. H zone

10. Z disc

11. I band

12. A band

13. I band

14. M line

15. Thin(actin) filament

16. Thick(myosin) filament

17. Sarcomere

18. Z disc

19. M line

20. Z disc

21. I band thin filaments only

22. H zone thick filaments only

23. M line thick filaments liked by accessory proteins

24. Outer edge of A band thick and thin filaments overlap

1. Dark A band

2. Light I band

3. Nucleus

4. Myofibril

5. Mitochondrion

6. Sarcolemma

1. Thin (myosin) filament

2. Thick (actin) filament

3. Z disc

4. H Zone

5. Z disc

6. I band

7. A band

8. I band

9. M Line

Sarcomere

smallest functional contractile unit of muscle. From Z disc of an I band to next Z disc

Transverse (T) tubule

indention of the sarcolemma (plasma membrane) forms a tubule at A/I band junction

• A band: region of sarcomere containing thick filaments

• I band: region of sarcomere containing only thin filaments

Sarcoplasmic reticulum

muscle cell’s smooth endoplasmic reticulum, used to store calcium (Ca2+) ions

Triad

structure consisting of two terminal cisterns of the sarcoplasmic reticulum and a transverse tubule between them

1. Sarcolemma

2. Myofibril

3. I band

4. A band

5. I band

6. Z disc

7. H zone

8. Z disc

9. M line

10. Sarcolemma

11. Triad

12. T tubule

13. terminal cisterns of the SR (2)

14. Tubules of the SR

15. Myofibrils

endomysium

Muscle fibers are ensheathed in connective tissue called endomysium

perimysium

Layer of connective tissue surrounding a bundle of muscle fibers.

fascicle

A bundle of muscle fibers surrounded by perimysium.

• Ensheathed muscle fibers are then bundled

  together in collagen membrane called perimysium

  to form a fiber bundle called a fascicle.

• blood vessels feeding the muscle are found between individual fascicles

epimysium

Fascicle bundles then are bundled together by dense connective tissue called epimysium

aponeuroses

Flattened sheets of connective tissue that connect muscles to muscles or muscles to bones.

1. tendon

2. Epimysium

3. Perimysium wrapping fascicle

4. Endomysium (between Individual muscle fibers

5. Muscle fiber

6. Perimysium

7. Fascicle

8. epimysium

9. Perimysium

10. Endomysium

11. Muscle Fiber within fascicle