Joints and the Muscular System Flashcards
What are joints
The point of contact between 2 bones, cartilage and bone or teeth and bone.
Joint structure determines its combination of strength and flexibility
What are the structural classification joints?
- Based on the presence or absence of synovial cavity & type of connecting tissue
- Fibrous joints: no synovial cavity (held together by fibrous connective tissue rich in collagen fibres)
- Cartilaginous: no synovial cavity (held together by cartilage)
- Synovial joints: bones have a synovial cavity (united by dense irregular connective tissue of an articular capsule & often by accessory ligaments)
What are functional classification joints?
- Based on the degree of movement permitted
- Synarthrosis: an immovable joint
- Amphiarthrosis: a slightly moveable joint
- Diarthrosis: a freely moveable synovial joint
What are fibrous joints
- Permit little or no movement
- 3 TYPES:
1) Suture - synarthrosis
2) Sydemosis - amphiarthrosis
3) Gomphosis- synarthrosis
What are cartilaginous joints
Offers little or no movement
connected by fibrocartilage or hyaline cartilage
1) Synchondrosis - hyaline cartilage
2) Symphysis - bones covered with hyaline cartilage but joined by a broad flat disc of fibrocartilage
What are synovial joints
- Synovial cavity between articulating bones allows joint to move freely
- Bones at joints are covered by hyaline articular cartilage that reduces friction between bones in a joint and also helps absorb shock
- Articular capsule surrounds the joint, encloses the synovial capsule & utilises articulating bone
Describe the fibrous capsule of the synovial joint
Outer layer of dense connective tissue which attach to the periosteum of articulating bones
What are ligaments
Fibres of fibrous capsule arranged in bundles
- bone to bone
- elastic & adapted for resisting strains
- main mechanical factor holding bones together
What is the synovial membrane
The inner layer composed of areolar connective tissue with elastic fibres
Articular fat pads - adipose tissue
What is the synovial fluid and what is it’s function
- A thin film secreted over surface
- Reduces friction by lubricating joint
- Supplies nutrients and removes metabolic waste
What movements can the synovial joint perform?
1) Gliding - simple movement
2) Angular - flexion, extension, hyperextension, abduction, circumduction
3) Rotation - bone revolves around its own longitudinal axis
What are the types of synovial joint and what movements do they provide
1) Planar - Gliding movements
2) Hinge - flexion & extension
3) Pivot - Rotation
4) Condyloid - Flexion, extension, abduction, adduction & circumduction
5) Saddle - Flexion, extension, abduction, adduction & circumduction
6) Ball & Socket - Flexion, extension, abduction, adduction, circumduction & rotation
What are the effects of aging on joints
- Decreased production of synovial fluid
- Articular cartilage becomes thinner
- Ligaments shorten & lose flexibility
- Influenced by genetic factors & wear & tear
What are the common joint disorders?
1) Osteoarthritis - degenerative joint disease
2) Rheumatoid arthritis - autoimmune disease
3) Sprain- forcible wrenching or twisting of a joint that stretches or tears it’s ligament
Explain Osteoarthritis
degenerative joint disease
Joint cartilage loss
Most common, affects larger joints first (knees, hips)
Aging, joint irritation, wear and abrasion
Explain Rheumatoid arthritis
autoimmune disease
Body attacks its own cartilage and joint linings
Smaller joints first (fingers)
Inflammation of the synovial membrane
What is a sprain
forcible wrenching or twisting of a joint that stretches or tears its ligament
May damage local blood vessels, muscles, tendons
Swelling occurs, painful, difficult to move joint
What are the types of muscle tissue
1) Skeletal - attached to bones & moves skeleton (striated, voluntary)
2) Cardiac - heart wall (striated, involuntary)
3) Smooth - walls of hollow internal structures such as blood vessels, airways, stomach, intestines (non-striated, involuntary)
What are the 5 functions of muscle tissue?
1) Produce body movements
2) Stabilise body positions
3) Regulating organ volume (e.g. sphincters prevent outflow - stomach, bladder)
4) Moving substances within the body
5) Produce heat
What are the connective tissue components
1) Epimysium (entire muscle)
2) Perimysium (bundles of 10 to 100 muscle fibres)
3)Endomysium (indiv muscle fibres)
4)Tendon (muscle to bone; inelastic; dense connective tissue; parallel bundles of collagen fibres)
Describe nerve & blood supply
Rich supply needed
Directly related to contraction
Contraction requires ATP
Large amounts of nutrients and oxygen required for ATP synthesis
Waste products of ATP reactions removed
Each fibre makes contact with a neuron at the neuromuscular junction
What are the 3 types of skeletal muscle fibres
Slow oxidative fibres (SO) – slow contraction, resistant to fatigue
Fast oxidative-glycolic fibres (FOG) – intermediate contraction, moderate resistance to fatigue
Fast glycolic fibres (FG) – most powerful and rapid contractions, intense movements of short duration and fatigue quickly
What happens to skeletal muscle during exercise?
Exercise induces changes in fibre type
Endurance type exercise gradually produce a change of some FG fibres into FOG fibres
Exercises that require strength for short periods produce an increase and change in size of FG fibres
Increase in size due to increased synthesis of thick and thin filaments
What are the effects of aging on muscular tissue
Beginning at age 30
Slow progressive loss of muscle tissue
Replaced by fibrous connective tissue and fat
Decrease in muscle strength
Slower muscle reflexes
Loss of flexibility
