Week 2 (1B)

Joints and cartilage, muscle basics

Types of cartilage

• Elastic cartilage (with elastic fibers, maintain structure shape)

• Hyaline cartilage (articular cartilage, smooth surface for glide and support at synovial joints)

• Fibrocartilage (durable, joint support andd cushioning)

What is the name of the cell that makes up cartilage

Chondrocytes

Visco = ?

Viscosity 黏度

What type of connective tissue is hyaline cartilage?

Viscoelastic connective tissue (solid at first but overtime when force applies it will become liquid)

• disturbutes load over wider area

• smooth surface reduces friction

what fibers does hyaline cartilage have

type ll collagen fibers

Whats osteoarthritis

• Loss of hyaline cartilage

Rheumatoid arthritis

• Inflammation of the synovial cavity and cartilage

• decreases mobility over time

What type of fiber does fibrocartilage contain

• type l and type ll collage

• create disc-like structures within joints (between scapula and humerus, between femur and tibia(menisci, a type of fibrocartilage elements) , pubic symphysis)

Factors contributing to range of motion

• Shape and arrangement of articulating surfaces

• Ligaments crossing the joint

• Surrounding muscles

What considers grade 1 ligament sprain

• Stretching or sightly tearing

What considers grade 2 ligament sprain

Incomplete tear

What considers grade 3 ligament sprain

Complete tear

What does PRICE stands for

• Protection

• Rest

• Ice

• Compression

• Elevation

Differences between strains and sprains

• Strains: Muscles and tendons tear

• Sprains: ligament tear

3 types of muscle

• Skeletal muscle

• Cardiac muscle

• Smooth muscle

what is the name of the cells that make up muscle

Myocytes

What type of control are considered for cardiac and smooth muscles?

• involuntary control

Where can smooth muscles be found?

• viscera(inner organs)

• blood vessels

• skin

are smooth muscles striated

Not striated

are cardiac and skeletal muscles striated

Yes

Basic muscle properties

• Electrical excitability

• Contractility

• Extensibility

• Elasticity

order of the muscle terms

muscle → fascicle → muscle fiber(myocytes) → myofibril (repeating units of sarcomeres)

What are sarcomeres made of

• Actin(thin filament) and myosin (thick filament)

Where do blood vessels and nerves locate in a muscle

• fascia (connective tissue)

On top of the muscle

whats concentric contraction

• Overlapping of actin and myosin

• Shortening muscles

whats eccentric contraction

Lengthening muscles

Whats the contralateral control

• left side of the brain controls right side of the body

• vice versa

What is a motor unit

• one motor neuron connects to several muscle fibers

Whats an origin

• immobile attachment (usually proximal)

Whats an insertion

• Mobile attachment (distal)

Isometric contraction

• Muscle contracts but does not shorten

What does isotonic contraction means

the muscles are moving during contraction

Concentric contraction

Muscle shortens during contraction

Eccentric contraction

Muscle lengthens during contraction

Agonist

• muscles that primarily drive the movement (concentric)

Antagonist

• Controls, slows, or resists the agonist (eccentric)

Synergist

• ASSIST THE AGONIST (concentric)

Muscle atrophy

• Lose muscle progressively from the age of 30

• Muscle mass is replaced by fibrous connective tissue and adipose(fat)

what causes muscle atrophy

• loss of motor neurons, muscle fibers

• slower conducting speeds

Benefits of exercising

• increase muscle mass, bone density and neuron firing rate

Grade 1 muscle strain

• stretching or sightly tearing

Grade 2 strain

• incomplete tear

Grade 3 strain

Complete tear

• DOESNT ALWAYS REQUIRE SURGERY!