Chapter 9 Part 1 Review Lesson

Poll

What is the name of the structure that connects a muscle to the bone?

• Sarcolemma

• Sarcomere

• Fascia

• Tendon

Poll

What is the largest level of structural organization for muscles?

• Fascicle

• Muscle Bundle

• Myofibril

• Myofilament

Poll

A bundle of muscle cells is known as a...

• Sarcomere

• Myofilament

• Fascicle

• Muscle Bundle

Poll

What is the general name for the connective tissue that wraps around the outside of the first 3 levels of muscular structure?

• Fascia

• Perimysium

• Sarcoplasmic Reticulum

• Tendon

Poll

What is the name for the muscle cell membrane that wraps around each individual muscle fiber?

• Endomysium

• Sarcolemma

• Sarcomere

• Epimysium

Skeletal Muscle –

Bundles of bundles of cells

Muscle Bundle

Fascicle

Muscle Fiber

Epimysium

Perimysium

Endomysium

Fascia

Levels of Organization in Muscles

• Level 1: Muscle (organ level)

– Each is separated and distinguishable from other

muscles by layers of fibrous connective tissue called
fascia

– Tendon: fascia (epimysium + perimysium + endomysium) extends

beyond the end of the muscle fiber to form a cord

Levels of Organization in Muscles

• Level 2: Fascicle (a portion of the muscle)

– Structure: discrete bundle of muscle cells segregated

from the rest of the muscle by connective tissue
covering

– Perimysium – connective tissue wrapping around the

fascicle

Levels of Organization in Muscles

• Level 3: Skeletal Muscle Fiber (cell)

– Structure: elongated cells called fibers
– Has a banded (striated) appearance
– Each fiber is considered a single cell in the muscle
– Can be multinucleated
– Endomysium – connective tissue wrapping around the

muscle fiber

– Sarcolemma – muscle cell membrane

Poll

What is the name for the long, contractile organelle unique to muscle fibers?

• Myofibril

• Myofilament

• Actin

• Myosin

Poll

A section of a myofibril that extends from Z disc to Z disc is know as...

• Sarcolemma

• Sarcoplasmic Reticulum

• Sarcomere

• Fascicle

Poll

What is the name for the protein fibers that make up a sarcomere?

• Myofibrils

• Myofilaments

• Perimysium

• Fascia

Poll

What is the name for the thick myofilament?

• Myofibril

• Muscle Fiber

• Actin

• Myosin

Levels of Organization in Muscles

• Level 4: Myofibril or Fibril (organelle)

– Structure: rod-like contractile element found within the

sarcolemma

– Made of 2 myofilaments (actin & myosin)

• Under the microscope they look like striations

– 1 muscle fiber has hundreds to thousands of myofibrils

Levels of Organization in Muscles

• Level 5: Sarcomere

– Structure: a segment of a myofibril between 2 Z discs
– Contractile unit
– Made of myofilaments (level 6: actin & myosin) made of contractile proteins

• Actin: thin filaments
• Myosin: thick filaments

Poll

Which region of the sarcomere contains both thick and thin myofilaments (actin + myosin)?

• A Band

• I band

• H Zone

• Z Disc

Poll

Which region of the sarcomere contains only thin myofilaments (actin)?

• A Band

• I band

• H Zone

• Z Disc

Poll

Which region of the sarcomere contains only thick myofilaments (myosin)?

• A Band

• I band

• H Zone

• Z Disc

Banding Patterns

• A band – dark segment made of thick myosin

filaments and overlapping thin actin

• I band – light segment made of thin actin filaments
• H zone – lighter stripe in middle of A band with only

thick myosin filaments

• M line – dark line that bisects the H zone
• Z disc – dark line down the midline of the I band

– Sarcomere is between 2 Z discs

• An A band and ½ an I band on each side

Myofilaments: Banding Pattern