Chapter 7: THE MUSCULAR SYSTEM – MOVEMENT FOR THE JOURNEY Name______________________

I. Introduction

A. The muscular system allows for _______________________.

1. External motion of the arms and legs

2. Internal motion including the movement of the digestive system, the _______________________ system, and the respiratory system

B. Different types of muscles allow for both external and _______________________ movement.

II. Overview

A. Muscle is a general term for all contractile tissue.

1. Contraction—muscle tissue becomes _______________________ and thick because of a nerve impulse.

2. ______________________ occurs when impulse ends

3. Alternating contraction and _______________________ causes _______________________.

B. Muscle tissue is constructed of bundles of these fibers, approximately the thickness of human hair.

III. Types of muscles

A. Skeletal muscle

1. Attached to _______________________; provide movement for the body

2. Tendons—fibrous tissues that attach skeletal muscles to _______________________

3. Striated-look striped

4. _______________________ —movement is controlled by conscious thought

5. Contraction and relaxation

a. Contraction—_______________________ of muscle

b. All movement is a result of contraction of primary movers and _______________________ of opposing muscles.

6. Types of movements

a. Rotation—_______________________ movement that occurs around an axis

b. Abduction—movement _______________________ from midline

c. Adduction—movement _______________________ the midline

d. Extension—_______________________ the angle between two bones connected at a joint

e. Flexion—_______________________ the angle between two bones

7. Movement at the cellular level

a. Muscle ____________

i. Each muscle cell is an elongated fiber.

ii. Several muscle fibers can be bundled together to form a specific muscle segment.

b. Sarcomeres

i. Sarcomeres are the functional _____________________ units of each fiber.

ii. Each sarcomere has two types of threadlike structures called thick and thin myofilaments.

iii. _______________________ myofilaments are made up of the protein myosin.

iv. _______________________ myofilaments are made up of the protein actin.

c. Muscle Contraction

i. Acetylcholine, a _______________________, is released from the nervous system.

ii. This causes contraction by causing myosin heads to bind to actin filaments (crossbridge formation).

iii. Energy is needed for contraction and relaxation.

________________(adenosine triphosphate)

d. Muscular fuel

i. Oxygen and _______________________ to make ATP

ii. _______________________ stored in muscle can be converted to glucose.

iii. Fat can be stored for energy.

iv. Muscle blood supply and color.

a. Higher demand muscles also have a greater blood supply to carry much-needed oxygen.

b. The greater blood supply gives them a darker color.

e. Muscles and body temperature

i. Muscles produce _______________________.

ii. Producing heat is important in maintaining body temperature.

iii. Shivering

f. Rigor Mortis

i. When a body dies, all the stored _______________________ is unable to be pumped back out of the muscles.

ii. Excess calcium remains in the muscles throughout the body and causes muscle fibers to shorten and ______________________ the whole body.

iii. Shortage of ATP also contributes.

B. Smooth muscle

1. Also called visceral _______________________

2. Found in hollow organs (except heart) and tubes, such as blood vessels

3. Involuntary muscles; slower than skeletal muscles

4. Action

a. _______________________ the diameter of a blood vessel is called vasodilation.

b. _______________________ the diameter of a blood vessel is called vasoconstriction.

c. Sphincters—close and open tubes

C. Cardiac muscle

1. Found in the wall of the _____________________

2. Involuntary

3. Fibers are shorter and receive a richer supply of blood than any other muscle in the body.

4. Intercalated disks—link fibers; causing one fiber to contract and then pull the next one into a contraction, creating a domino effect

5. Cardiac muscles do not _______________________ themselves, leading to scarring.

IV. Muscle Tone (p. 160)

A. Tonus (muscle tone)—partial contraction of a muscle with resistance to stretching

B. _______________________ —increased muscle size

C. _______________________ —muscle wasting from disuse

V. Common Muscular System Disorders

A. Myalgia: pain or tenderness in a muscle

B. Fibromyalgia: mainly affects _______________________ under 40 but is not fully understood; symptoms include aches, pains, and muscle stiffness with specific tender points; cause is unknown but is linked with chronic fatigue syndrome.

C. Paralysis: partial or total loss of function in _______________________ muscles; can be either flaccid or rigid paralysis

D. Spasm or cramp: involuntary sudden and violent contraction of a muscle for a prolonged period of time

E. Sprains: tears or breaks in _______________________

F. Strains: actual tears in _______________________ or tendons

G. Shin splints: inflammatory condition of the extensor muscles and surrounding tissues of the lower leg; often found in _______________________

H. Hernia: tear in the muscle wall through which an _______________________ of the body protrudes

I. Tendinitis: inflammation of _______________________

J. Electromyography: a diagnostic test in which a muscle or group of muscles are stimulated with an electrical impulse, causing contraction, allowing the strength of the contraction to be measured

K. Neuromuscular disorders

1. Myasthenia gravis

a. Gradually increasing profound _______________________ weakness

b. Drooping eyelid frequently the first symptom

2. Muscular dystrophy

a. Inherited muscular diseases

b. Muscle fibers _______________________

c. Progressive muscular weakness occurs

3. Guillain-Barré syndrome

a. Disorder of the _______________________ nervous system that causes flaccid paralysis and the loss of reflexes

b. Ascends from the feet and progressing to the head

c. Paralysis peaks in 10 to 14 days and then subsides gradually

4. Tetanus

a. Creates rigid paralysis, and any minor stimulus causes muscles to go into a major spasm

b. Caused by toxins produced by a _______________________ found in the ground and can be spread by any type of puncture, not just a rusty nail

5. Botox

a. Botulism is a potentially deadly disease resulting from _______________________ poisoning with the Clostridium botulinum bacteria.

b. Science can utilize botulinum toxins for medical and cosmetic treatment.

c. Small amounts of botulinus toxin are injected into facial muscles to stop previously untreatable facial twitching by paralyzing the muscles.

d. Toxin also is used to treat wrinkles without surgery; known as _______________________ injections.

Test Your Knowledge 7–1 Page 147

1. Muscle contraction is the ability of muscle to a. Relax when there is no nerve impulseb. Get smallerc. Shorten with forced. Recoil

2. Smooth muscle is found in all the following excepta. Airwaysb. Digestive systemc. Blood vesselsd. Heart

3. Which types of muscles are striated?a. Smooth and cardiacb. Cardiac and skeletalc. Skeletal and smoothd. Smooth only

4. Striations area. Collagen strands that strengthen the muscleb. Tendonsc. Muscle cellsd. Stripes on the surface of muscles

Test Your Knowledge 7–2 Page 151

1. Looking right and left at a stop sign: _________________________.

2. The first movement in curling a weight: _________________________.or _________________________.

3. Returning the weight from the curled position to your side: _________________________.or _________________________.

4. The muscle that causes a movement is the: _________________________or ___________________________ _______________________.

5. The muscle attachment that does not move during muscle is the: _________________________of _________________________.

Test Your Knowledge 7–3 Page 155

1. The thin myofilament needed for muscle contraction is called: _________________________.

2. The two ingredients needed for crossbridges to form and break are _________________________and _________________________.

3. The fundamental unit of muscle contraction is the _________________________.

4. Sodium flowing into muscle fibers is triggered by the binding of _________________________released from neurons.

5. During contraction _________________________heads bind to _________________________myofilaments.

Test Your Knowledge 7–4 Page 158

1. The _________________________are the primary knee flexors.

2. The _________________________, knee extensors, originate on the _________________________and insert on the _________________________and _________________________.

3. The _________________________originates on the sternum and clavicle and inserts on the mastoid process.

4. This muscle inserts via the Achilles tendon: _________________________.

5. The _________________________, an elbow flexor, is the antagonist of the _________________________ an elbow extensor.

6. Ben is in the middle of the Olympic trials for the 400-meter hurdles when he falls to the ground clutching his leg. Upon examination he has pain in the posterior thigh and cannot flex his knee. Which muscles are injured?

His _________________________.

REVIEW QUESTIONS Page 166

Multiple Choice

1. Another name for voluntary muscle is:a. Skeletalb. Smooth c. Cardiacd. Non-striated

2. Which structure does not contain smooth muscle?a. Blood vesselsb. Heart c. Digestive tractd. Bronchi

3. Most skeletal muscles attach to bones via:a. Ligamentsb. Joints c. Flexorsd. Tendons

4. The state of partial skeletal muscle contraction is known as:a. Homeostasisb. Muscle tonec. Partialus contractusd. Flexerus

5. Cardiac muscle:1. Is a voluntary muscle2. Has intercalated discs to assist contraction3. Regenerates after injury4. Lines the blood vessel

b. I onlyc. I and II d. II onlye. I, II, III, and IV

6. Jill falls and twists her ankle. Later she cannot dorsiflex her foot. Her doctor tells her she has torn a tendon and must have surgery. Which tendon?

a. Patellarb. Calcanealc. Rotator cuffd. Anterior cruciate

7. Sam wakes up one morning unable to move his toes. Within a few hours he can’t move his legs and call 911. By morning he is completely paralyzed. What has happened to him?

a. Tetanusb. Guillain Barrec. Muscular dystrophyd. Muscular atrophy

Fill in the Blank

1. A sudden or violent muscle contraction is a _________________________ .

2. Partial or total loss of voluntary muscle use is _________________________.

3. A tear in the muscle wall through which an organ can protrude is a _________________________.

4. The body stores a carbohydrate called _________________________in the muscle; it can be converted to a usable energy source.

5. _________________________ means pain or tenderness in the muscle.

6. Elbow flexion is the action of the _________________________muscle.

Short Answer

1. List the three major muscle types and give an example of each.