EXAM 4: Muscular Structure

Question 1

Types of muscle tissue

Answer 1

Skeletal, Smooth, Cardiac

Question 2

Characteristics of skeletal muscle

Answer 2

Voluntary, striated, multinucleate, attached to bone or fascia (connective tissue)

Question 3

Characteristics of cardiac muscle

Answer 3

Involuntary, striated, mononucleate, auto rhythmic (cells can self regulate contraction)

Question 4

Characteristics of smooth muscle

Answer 4

Involuntary, non-striated, mononucleate

Question 5

5 properties that all muscle tissue share

Answer 5

Excitability (respond to chemicals released from motor neurons)
conductivity (ability to propagate electrical signals over membrane)
contractility (ability to shorten and generate force)
extensibility (ability to be stretched without damaging the tissue)
elasticity (ability to return to original shape after being stretched)

Question 6

What is a muscle formed by

Answer 6

Formed by a group of fascicles

Question 7

What is a fascicle formed by

Answer 7

Formed by a group of muscle fibers

Question 8

What are muscle fibers formed by

Answer 8

Formed by a group of myofibrils

Question 9

Anatomy of a myofibril

Answer 9

Contain bundles of protein filaments, organized into sacromeres

Question 10

Functions of connective tissue

Answer 10

Protects muscle cells
Reduces friction
Creates space for extracellular fluid

Question 11

Three types of connective tissue and their function

Answer 11

Epimysium: covers entire muscle
Perimysium: covers fascicles
Endomysium: covers muscle fibers

Question 12

Muscle connections: Muscle to bone

Answer 12

Indirect
- Collagen fibers of epimysium form strong fibrous tendon (dense regular connective tissue) that merges into periosteum (outer covering of bone)
- Most common connection
Ex. Biceps brachii, gastrocnemius (calf muscle)

Question 13

Muscle connections: muscle to muscle

Answer 13

Direct (fleshy)
- Collagen fibers of epimysium are directly continuous with periosteum
- Looks like muscle emerges directly from bone
- Ex. Intercostal muscles (ribs)

Question 14

Muscle connections: muscle to fascia

Answer 14

• Muscles insert to broad sheet of connective tissue called an aponeurosis: similar in structure as a tendon, but broad and flat
• Ex. Abdominal aponeurosis

Question 15

What is muscle shape based on

Answer 15

It is based on the organization of fascicles

Question 16

Circular muscle shape

Answer 16

Fascicles concentrically arranged around an opening (ex: orbicularis oris or mouth)

Question 17

Convergent muscle shape

Answer 17

Fascicles from a broad area converge on a common attachment ( pectoralis major)

Question 18

Parallel/Fusiform muscle shape

Answer 18

Fascicles parallel to long axis of muscle (ex: Sartorius)

Question 19

Pennate Muscle shape

Answer 19

Fascicles attach at an angle to a central tendon (ex: Deltoid)

Question 20

How does the shape of a muscle effect its properties

Answer 20

Muscles with more muscle cells can generate more force and muscles with longer muscle cells can contract further