Week 4 - Joints and movement/Muscle

Question 1

What two functions do joints have?

Answer 1

Hold bones together

Facilitate movement

Question 2

What are the structural classification of joints?

Answer 2

• Fibrous connective tissue (for strength and support)
• Cartilage (For cushioning and strength and flexibility)
• Mixture of both plus a special fluid (synovial fluid) (Synovial joint for cushioning and lubrication of joint)

Question 3

Characteristics of fibrous joints

Answer 3

• No joint cavity
• Collagen fibres extend from matrix of one bone to another
• Amount of movement within the joint depends on the length of collagen fibre

Question 4

what are the 3 different fibrous joints

Answer 4

• Suture (skulls bony joints)
• Syndesmosis (Ligaments)
• Gomphosis (Peg in socket, Teeth)

Question 5

2 types of cartilaginous joints

Answer 5

symphyses (Pubic, pelvic)

synchondroses (hyaline cartilage) Bone, Cartilage, bone

Question 6

Characteristics of synovial joint

Answer 6

• Most common
• Articulating bones are separated by a fluid-filled joint cavity
• Lubricated by synovial fluid
• Enclosed in a double layered fibrous capsule
• Reinforced by ligaments

Question 7

5 Basic components of synovial joint

Answer 7

1. Articular cartilage (hyaline)
2. Synovial cavity
3. Articular capsule
   - outer fibrous layer
   - inner synovial membrane
4. synovial fluid
   - secreted by the synovial membrane
   - plus hyaluronic acid plus phagocytes
   - traps water in synovial cavity
5. Ligaments (“Strap-like” tissue)

Question 8

Difference between tendons and ligaments

Answer 8

Tendons hold muscle to bone

Ligaments hold bone to bone

Question 9

3 types of functional classification of joints

Answer 9

• Synarthroses
• • Syn = together
• • immovable
• Amphiarthroses
• -Amphi = both sides
• -Slightly moveable
• Diarthroses
• • Dia = apart
• • Freely moveable

Question 10

Angular movement in bones (increase or decrease angle between two bones) terms

Answer 10

1. Flexion/Extension
   - Usually along the sagittal plane
   - Flexion decreases angle
   - Extension increases angle
2. Abduction/adduction
   - Abduct = take away
   - Adduct = bring closer
3. Circumduction/Rotation

Others

• Supination (turning outwards/supine)
• Pronation (turning inwards/prone)
• Dorsiflexion (lifting the foot up)
• Plantar flexion (pointing the toe)

Question 11

4 Characteristics of muscle tissue

Answer 11

Excitability

Contractility

Extensibility

Elasticity

Question 12

Three types of muscle tissue

Answer 12

1. Skeletal: striated, voluntary control, get tired
2. Cardiac muscle: striated, involuntary control (heart)
3. Smooth muscle: non-striated, involuntary control

Question 13

the 3 sarcomere protein composition

Answer 13

Contractile proteins
- myosin and actin

Regulatory proteins

• switch contraction on and off
• troponin and tropomyosin

Structural proteins

• provide correct alignment
• elasticity and extensibility

Question 14

the 2 regulatory proteins

Answer 14

troponin and tropomyosin

Question 15

Thick filaments characteristics

Answer 15

• Myosin filaments
• 2 Globular heads
• Heads face outwards
• Bind to Actin!
• ATP binding site

Question 16

Composition of thin filaments

Answer 16

• mainly Actin
• Tropomyosin
• Troponin

Question 17

Resting membrane potential Definition

Answer 17

Due to the selective permeability of the plasma membrane, the inside of the cell is negatively charged compared with the outside.

• -70mV inside is more negative

Question 18

Nerve impulses are also known as

Answer 18

Action potential

Question 19

Hypertrophy characteristics

Answer 19

(Hyper = Too much)

• Increase in diameter of muscle fibres
• Resulting from forceful, repetitive muscular activity
• increase in cell size, not cell number

Question 20

Atrophy characteristics

Answer 20

(A = lacking, without/ trophy = nourishment)

• Wasting away of muscles
• Caused by disuse or damage to nerve supply
• can be irreversible in some cases

Question 21

Cardiac muscle characteristics

Answer 21

• Only found in the heart
• Involuntary control
• Striations present
• Short, Branching shape
• One or two nuclei per cell

Question 22

Smooth Muscle Characteristics

Answer 22

• Involuntary control
• one nucleus per cell
• No striations
• Spindle=shaped
• lines hollow organs and tubes

Question 23

Types of smooth muscle

Answer 23

Unitary smooth muscle

• Most common
• In the walls or all hallow organs except heart

Multi unit smooth muscle

• Gap junctions and spontaneous depolarisations are rare
• Muscle fibres that are structurally independent
• Large airways to lungs, large arteries, arrector pili, internal eye mucles