Joints and the Muscular System

Question 1

What are joints

Answer 1

The point of contact between 2 bones, cartilage and bone or teeth and bone.
Joint structure determines its combination of strength and flexibility

Question 2

What are the structural classification joints?

Answer 2

• 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)

Question 3

What are functional classification joints?

Answer 3

• Based on the degree of movement permitted
• Synarthrosis: an immovable joint
• Amphiarthrosis: a slightly moveable joint
• Diarthrosis: a freely moveable synovial joint

Question 4

What are fibrous joints

Answer 4

• Permit little or no movement
• 3 TYPES:
  1) Suture - synarthrosis
  2) Sydemosis - amphiarthrosis
  3) Gomphosis- synarthrosis

Question 5

What are cartilaginous joints

Answer 5

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

Question 6

What are synovial joints

Answer 6

• 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

Question 7

Describe the fibrous capsule of the synovial joint

Answer 7

Outer layer of dense connective tissue which attach to the periosteum of articulating bones

Question 8

What are ligaments

Answer 8

Fibres of fibrous capsule arranged in bundles
- bone to bone
- elastic & adapted for resisting strains
- main mechanical factor holding bones together

Question 9

What is the synovial membrane

Answer 9

The inner layer composed of areolar connective tissue with elastic fibres
Articular fat pads - adipose tissue

Question 10

What is the synovial fluid and what is it’s function

Answer 10

• A thin film secreted over surface
• Reduces friction by lubricating joint
• Supplies nutrients and removes metabolic waste

Question 11

What movements can the synovial joint perform?

Answer 11

1) Gliding - simple movement
2) Angular - flexion, extension, hyperextension, abduction, circumduction
3) Rotation - bone revolves around its own longitudinal axis

Question 12

What are the types of synovial joint and what movements do they provide

Answer 12

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

Question 13

What are the effects of aging on joints

Answer 13

• Decreased production of synovial fluid
• Articular cartilage becomes thinner
• Ligaments shorten & lose flexibility
• Influenced by genetic factors & wear & tear

Question 14

What are the common joint disorders?

Answer 14

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

Question 15

Explain Osteoarthritis

Answer 15

degenerative joint disease
Joint cartilage loss
Most common, affects larger joints first (knees, hips)
Aging, joint irritation, wear and abrasion

Question 16

Explain Rheumatoid arthritis

Answer 16

autoimmune disease
Body attacks its own cartilage and joint linings
Smaller joints first (fingers)
Inflammation of the synovial membrane

Question 17

What is a sprain

Answer 17

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

Question 18

What are the types of muscle tissue

Answer 18

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)

Question 19

What are the 5 functions of muscle tissue?

Answer 19

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

Question 20

What are the connective tissue components

Answer 20

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)

Question 21

Describe nerve & blood supply

Answer 21

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

Question 22

What are the 3 types of skeletal muscle fibres

Answer 22

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

Question 23

What happens to skeletal muscle during exercise?

Answer 23

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

Question 24

What are the effects of aging on muscular tissue

Answer 24

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

Question 25

How does skeletal muscle produce movement

Answer 25

Flexors and extensors muscles (antagonists)
Produce movement by pulling on tendons
Tendons pull on bones
Muscle contracts it pulls one bone towards the other
Most movements occur because muscles are acting in groups rather than individually