slow twitch and fast twitch muscles

3 Types of Muscle

•1. smooth
•2. cardiac
•3 skeletal

Smooth muscle

• involuntary- you can’t control it
• Present in digestive organs and blood

vessels

• No striations
• One nucleus per cell

Cardiac Muscle caracteristics

• Found only in the heart
• One nucleus per cell
• Striated
• involuntary

Skeletal Muscle

• Voluntary
• Makes up muscles that attach to your

bones

• Striated
• Many nuclei

Multiple Choice

Which muscle type is striated and involuntary?

• cardiac

• smooth

• skeletal

• cardiac and smooth

How do muscles get their

energy?

•Cellular respiration!!!!

Multiple Choice

Where does cellular respiration occur in a muscle cell?

• sarcoplasmic reticulum

• myofibrils

• mitochondria

• sarcomere

Multiple Choice

Cellular respiration uses _____ and _______ to make energy.

• glucose and water

• glucose and carbon dioxide

• oxygen and glucose

• water and oxygen

What if the cells run out of

oxygen?

• Lactic acid fermentation results
• Without enough oxygen, cells convert

glucose to lactic acid in order to make
energy (ATP)

• Lactic acids builds up and
causes muscle fatigue

Multiple Choice

What is produced in muscle cells when there is a lack of oxygen during exercise?

• water

• ATP and lactic acid

• lactic acid

• oxygen and glucose

Multiple Choice

Oxygen is needed during lactic acid fermentation

• true

• false

Slow Twitch and Fast Twitch

Skeletal Muscle Fibers

ApproximateDistribution of Muscle Fiber
Types for Different Sports

Slow-Twitch

❖ Contract slowly

❖ More endurance

❖ Used in long distance running, biking or

swimming

Why do they have more endurance???

❖ Contain myoglobin to hold

extra oxygen

Has many mitochondria

❖ Myoglobin makes muscles dark

in appearance

Multiple Choice

What is myoglobin?

• an enzyme that speeds up cellular respiration

• a molecule used for energy in muscles

• a molecule used to store oxygen in muscles

• a substance that builds up in the muscle, causing muscle fatigue

Exercise increases the # of

mitochondria and the amount of myoglobin, not size of muscle

Fast-Twitch

❖ Contract fast

❖ Provide great strength for short

, rapid movements

❖ Ideal for: lifting, short sprints,

and explosive jumping

❖ Fatigue easily

Fast twitch Cont.
❖ Pale in color (lack myoglobin)

❖ Fewer mitochondria so they

rely on anaerobic respiration.
(lactic acid fermentation)

❖ Muscles increase in size

Multiple Choice

Fast twitch muscle fibers.....

• contract fast

• fatigue quickly

• are lighter in color

• all of these

Multiple Choice

contains a lot of myoglobin

• fast twitch

• slow twitch

• both

Multiple Choice

Relies on anaerobic respiration to make energy for contraction

• fast twitch

• slow twitch

• both

Multiple Choice

Can increase in size with training

• fast twitch

• slow twitch

• both

Multiple Choice

Which is smaller than a muscle fiber?

• fascicle

• muscle cell

• myofibril

Multiple Choice

The structure that connects muscle to bone

• tendon

• ligament

• fascia