TEAS 1.6 Muscular System

What are the three types of muscle tissue in the body?

• Skeletal

• Cardiac

• Smooth

What is skeletal muscle?

attaches to bones throughout the body and is responsible for movement of bones and body parts.

Key characteristics of skeletal muscle

• striated (striped) appearance

• is very strong

• the only voluntary muscle tissue in the body

Where is cardiac muscle found?

exclusively in the heart

What is the function of cardiac muscle?

pumps blood throughout the body continuously without conscious effort.

Characteristics of cardiac muscle

• It is striated

• involuntary

Function of smooth muscle

It regulates internal organ functions and passage movements

What are the characteristics of smooth muscle?

• non-striated (smooth appearance)

• the weakest of all muscle tissues

• involuntary

• It is found in

Where is smooth muscle found?

• walls of hollow organs (stomach, intestines)

• blood vessels

• eyes

• reproductive system tracts

• skin

Which type of muscle tissue is voluntary?

Skeletal muscle

Which type of muscle tissue is striated and involuntary?

Cardiac muscle

What are tendons?

tough bands of connective tissue that have strong collagen fibers. They firmly attach muscle to bone.

How do muscles move?

by contracting and shortening their length, which pulls on the tendons, moving one bone closer to another bone that is stationary.

What are myofibrils?

long structures contained in muscles that are made of repeating sarcomere units.

What is a sarcomere?

the contracting unit of a muscle.

Each contains actin (thin protein filaments) and myosin (thick protein filaments).

What is actin?

the thin protein filaments found in sarcomeres.

What is myosin?

the thick protein filaments found in sarcomeres.

What is collagen?

the primary structural protein of connective tissue found in tendons.

What factors are skeletal muscles named based on?

their location, shape, and size.

What is required for an entire muscle to move?

• a coordinated effort by many nerves and fibers

• the use of ATP (adenosine triphosphate) to power the contraction and relaxation

What is ATP (adenosine triphosphate)?

the energy molecule that powers muscle contraction and relaxation.

What happens when a muscle is relaxed?

myosin and actin filaments are not attached.

What happens when muscles contract?

the actin and myosin filaments bind and are pulled together.

Describe the signal transmission process for muscle movement.

1. Brain sends message to specific body part

2. Nervous system transmits signal to appropriate muscle

3. Actin and myosin proteins slide past each other

4. Result: Contraction OR relaxation

What are the two basic motions responsible for all muscle movement?

Contraction and relaxation

What is contraction?

the process leading to shortening and/or development of tension in a muscle.

How do muscles respond to nerve impulses?

Receptors in muscles receive nerve signals and muscles respond with the appropriate magnitude and movement.

What can disrupt the signal and response system in muscles?

• muscle strain

• muscular dystrophy

• other muscular disorders

What is the muscular system?

an integrated system in the body that is vital for controlling involuntary and voluntary movement and affects every part of the body.

Approximately how much of a person's body weight is made up of muscles?

approximately half of a person's total body weight.

About how many named muscles are in the body?

about 700

Do skeletal muscles work alone?

No, skeletal muscles rarely work alone but rather often work in groups to produce movements.

Which are the thick filaments in a muscle cell?

Myosin

What is the role of tendons?

They connect muscle to bone.

Which type of muscle tissue is voluntary?

Skeletal muscle

Which muscles are located at the shoulder?

Deltoids and Trapezius