Muscle Types/ Levers

Question 1

Muscle Types

Answer 1

• skeletal
• smooth
• cardiac

Question 2

Skeletal Muscle

Answer 2

• “striated” (under a microscope you can see striations)
• under conscious control of the nervous system
• parallel muscle fibres

Question 3

Smooth Muscle

Answer 3

• involutary muscle under control of autonomic nervous system
• non-striated, non-parallel fibres
• surrounds fluid containing vessels such as the stomach, intestines, glands

Question 4

Cardiac Muscle

Answer 4

• involuntary muscle of the heart
• under autonomic nervous system control
• striated, non-parallel muscle fibres

Question 5

Functions of Skeletal Muscle

Answer 5

• Movement: contraction causes and inhibits movement
• Posture/balance: maintains posture and balance
• Protection: abdominals protect abdominal organs; muscles around mouth and eyes can close for protection of underlying tissue
• Body temp: contraction of muscle prod. heat

Question 6

Types of Muscular Contractions

Answer 6

• Isometric: muscle tension with no movement
• Isotonic concentric: tension in muscle as muscle is shortening
• Isotonic eccentric: tension in muscle as muscle is lengthening; usually the force that causes the movement is gravity as muscle lengthens under tension to control mvt cause by gravity

Question 7

Levers

Answer 7

3 types, have to have:

• fulcrum: point/joint around which movement occurs
• force: muscle or gravity is the force; force is applied to the moveable bone in the system
• resistance: weight to be moved

Question 8

1st Class Lever

Answer 8

-see saw
-fulcrum in middle, weight/resistance on either side
-ex. head extension:
>fulcrum: occipital condyles and C-1
>force: posterior muscles attachment to base of occipital
>resistance: weight of head (as presented by heads centre of gravity) anterior to the fulcrum

Question 9

2nd Class Lever

Answer 9

-wheelbarrow
-fulcrum at end of lever, resistance closer to fulcrum and force further (relative to resistance) from fulcrum
-ex. plantar flexion
>fulcrum: metatarsal-phalangeal joint
>force: attachment of superficial plantar flexor muscles (gastrocnemius, soleus, and plantaris) to the calcaneous bone
>resistance: weight of body (centre of gravity in middle of foot)

Question 10

3rd Class Lever

Answer 10

-you on the end of a long handled shovel
-fulcrum at end of lever, resistance toward other end of lever, force between resistance and lever
-ex. elbow flexion by biceps brachii
>fulcrum: elbow joint
>force: attachment of biceps brachii onto radius
>resistance: weight of forearm