Download Muscle

Ch. 6
The Muscular
System
Case Study Investigation
You are selected for an internship at the National
Space Biomedical Research Institute in Houston,
Texas. Part of your job is to monitor the health of the
astronauts for the National Aeronautics and Space
Administration (NASA) before, during, and after a
space mission. By chance, your time in the lab
corresponds with the return of an American astronaut
from the International Space Station. She just spent
171 days in the space station and is now getting back
to her research studies on earth. Unfortunately, it was
discovered that she would have to go through at least 3
weeks of physical therapy.
You learned from reading her physical health report that
she lost 30% of her skeletal muscle mass. Most of it
occurred within the last 2 months of the mission in space.
The normal muscle loss during a space mission is less
than 20%. A majority of muscle atrophy results from
disuse, yet she followed all the exercise programs NASA
requires. Your job is to assist the research team in
investigating her problem.
By the end of this chapter, you
will be asked to determine the
most likely cause of her
accelerated loss of muscle mass.
Applied Learning Outcomes
Use the terminology associated with the
musculature system
Learn about the following:
• Different types of muscle cells
• Muscle tissue development
• Gross and fine muscle structure
• Gross muscle function
• Muscle cell physiology
• Muscle types and actions
• Muscle development and growth
Understand the aging and pathology of the
musculature
Overview
Muscle cells change their shape by
shortening or_______________.
They are composed of specialized
_______________________
Over_______the body’s mass is
composed of muscle tissue, and over
90% of this muscle tissue is involved
in ____________________________
Muscles require ________________,
________________and
_____________________ and
release metabolic _______________
Chapter 6 – The Muscular System
Muscle
Three types of muscle are found in the human body:
a) __________ muscle
(slightly striated
& involuntary;
b) ____________ muscle
(striated &
voluntary)
c) ___________ muscle
(non-striated &
involuntary)
Skeletal Muscle Function
1. Skeletal Movements = pulling on bone (________________________)
____________________=muscle
responsible for the movement
____________= muscles that
help the prime mover
_____________= muscle that produces the opposite movement as prime mover
2. ___________________________: balance weight
distribution and hold muscles in position
a. _______ contraction:
only a few muscles
contract at a time;
NO shortening and
NO movement
3. Regulate Organ Volume
a. ______________: bands of smooth muscle that prevent outflow of
fluids from hollow organs
4. ____________________________within the body:
a. cardiac muscle – pumps blood
b. smooth muscle – moves food through digestive sys.
(__________________)
5. ______________Production: when muscles
_______________ they
produce heat
a. _______thermia – decrease in
body temp below normal
b. ______thermia – increase in
body temp above normal
raises eyebrow
closes jaw
closes eyes
smile muscle
closes jaw
extends head / neck
closes lips
yes/no muscle
Muscles of the Trunk
deltoid
abducts
arm
adducts
upper
arm
flex trunk
flexes
elbow
MUSCLES of the
ARM
extends
elbow
flexes forearm
pronates & supinates
flexes thigh + lower leg
(middle quadricep)
Quadriceps
extend the leg
(lateral quadricep)
(medial quadricep)
Vastus intermedius
(inner quadricep)
plantar-flexes ankles
dorsi-flexes ankles
plantar-flexes ankles
extends thigh
Hamstrings
flex the leg
adducts thigh
(middle hamstring)
(medial hamistring)
(lateral hamstring
Musculature:
Gross Anatomy
2. ______: rest of the muscle
(masseter)
3. ___________:
moveable bone the
muscle attaches to
(mandible)
1. _____________: stationary
bone the muscle attaches to
(zygomatic arch)
Origin:
Scapula /
Humerus
Sacs of synovial fluid btwn
tendon & bone for lubrication
Body
Biceps
Brachii
Insertion:
Radius
___________
attachs muscle
to bone
Concept Check #1
1. What are muscles composed of that allow them to do their jobs?
2. What are 5 functions of the muscular system.
3. How are the prime mover, synergist, and antagonist involved in
movement? If I were to flex my elbow what muscles would represent
the PM, S, and A?
4. What is a tonic contraction and give an example of one.
Concept Check #2
5. How do sphincters regulate organ volume?
6. Give an example of how cardiac and smooth muscle move
substances within the body.
7. How does the origin and insertion of a muscle differ? How are
they involved in muscle movement?
8. Research the origin and insertion for the following muscles:
Gastrocnemius: Origin:
Insertion:
Pectoralis major: Origin:
Insertion:
Skeletal Muscle Structure
surrounds _____________
surrounds each
surrounds entire
_____________
bundle of _____________
http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP13904 Muscle Structure Animation
Microcopic Muscle Cell Structure
 skeletal muscle cells are LONG, CYLINDRICAL cells covered
with an excitable membrane called the __________________
 sarcolemma contains proteins that ___________signals from other
cells/environment and _____________the information to the
muscle cells causing them contract
 contractile unit of muscle is called a sarcomere (thousands run the
length of a muscle cell)
 chains of sarcomeres form ________________________
 sarcomere contains
2 types of
____________________
1. thick m.f. contain
protein ___________
2. thin m.f.  contain
proteins _________,
__________________
& ________________
 __________________________
surrounds sarcomeres &
stores Ca for contractions
Sarcomere
marks
boundaries
between
sarcomeres
_________________________ Chain
http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter42/animations.html#
Myosin (_____)
Actin (_____)
Muscle Cell Function
 contraction occurs when sarcomeres shorten simultaneously
1. __________________– takes place at the ________________
junction (motor neuron meets muscle fiber)
 ____ causes nerve cell to release acetylcholine, a neurotransmitter,
which binds to sarcolemma and allows Na+ /K to cross
membrane
http://www.galaxygoo.org/biochem/neuro/nmj_flash.html
(basic neuromuscular junction animation)
2. Muscle _________________ – takes place inside muscle cell
 ion movement causes SR releases ____ which travels to
sarcomere to start contraction
 Ca binds to ____________ & removes ______________
(blocks myosin heads from attaching to actin)
 ________________________________ shortens
sarcomere  _______________http://www.blackwellpublishing.com/matthews/myosin.html
http://health.howstuffworks.com/muscle.htm/printable

Sliding filament theory animations
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter10/animation__action_po
tentials_and_muscle_contraction.html
_________________ muscle tension caused by Ca leakage out of SR into
sarcomere after death
Creatine phosphate, glycogen, & myoglobin  all serve as energy or oxygen
reserves for muscle contraction
3. Muscle ________________________when neural stimulations
stop exciting the sarcolemma
 Na+/K+ levels are completely recovered; _________________
 troponin/tropomyosin covers binding site  ______________
actin  sarcomere relaxes  muscle _________________
________
__________
Model
Types of Skeletal Muscle Fibers
unique muscle composition is genetically determined
https://www.23andme.com/health/Muscle-Performance/
Feature
________________Twitch
Fibers (Type I)
__________________Twitch
Fibers (Type IIb)
Size
Smallest
largest
Mitochondria
large amount
(get ATP through aerobic
processes)
small amount
(get ATP through anaerobic
processes)
Color
red
(high myoglobin content)
white
(low myoglobin content)
Speed of
Contractions
Slow
Fast
Resistance to
Fatigue
High (very fatigue resistant)
Low (not fatigue resistant)
Activities
Maintaining posture,
endurance activities (i.e.
marathon runners)
Rapid, intense movements of short
duraction (i.e. sprinters, throwing a
ball or weight lifting)
Concept Check #3
9. List the three membranes of muscle in order from superficial to
deep then explain how they each differ.
10. What is the name given to the membrane that surrounds a muscle
cell and why is it important?
11. What is a sarcomere? And how do the 2 myofilaments that make
up a sarcomere differ?
12. Draw a picture of a sarcomere and label the two different
myofilaments.
Concept Check #4
13. Why is the sarcoplasmic reticulum that surrounds the sarcolemma
so important?
14. What are the three stages of muscle cell contraction?
15. What is the neuromuscular junction and what occurs here?
16. Why is Ca necessary for starting a muscle contraction?
Concept Check #5
17. Explain the sliding filament theory.
19. Why would a leak of Ca from the sarcoplasmic reticulum cause
rigor mortis.
20. When does a muscle relax?
21. Why might marathon runners have more red twitch fibers and
sprinters have more white twitch fibers? Include speed of contraction
and fatigue resistance in your explanation.
Skeletal Muscle Action
 skeletal muscle structure responds to the amount of work it must do
 ___________________or lack of neural stimulation
 cells lose sarcomere __________
 contraction strength ____________
 muscle size decreases
(________________________)
 regular use & _____________________
 muscle _________________________
 muscle size increases (_________trophy)
 Does your muscle diameter increase OR does your sarcomere density
& strength increase w/o a significant increase in overall muscle size ???
(determined by genetic differences & different blood flow patterns)
Skeletal Muscle Action
 shortening of the muscle brings the insertion closer to the origin
 __________________- minimal level of stimulus required to
cause a fiber to contract
 muscle cells are controlled by ___________________with
different threshold levels so _________________________________
 _______________________– a fiber contracts completely or not at
all; It’s the difference in picking up 1 textbook or 25 textbooks.
________ = contracting more fascicles
_________________= producing more
contracting and relaxing groups
of fascicles.
Skeletal Muscle Action
 muscles can be categorized by the effect it has on joint
motion
• ________ – muscles that move a bone away from the
midline (deltoid, gluteus maximus)
•___________– muscles that move a bone closer to the
midline (gracilis, pectoralis major)
•_________– muscles that increase the angle of a joint
(tricep, quadriceps)
• ________ – muscles that decrease the angle of a joint
(bicep, hamstrings)
• ____________ – muscles that decrease the size of an
opening (esophogeal sphincter, rectal spincter)
Skeletal Muscle Action
 ___________ contractions: when a muscle is actively
shortening or lengthening
ex. lifting weights
 ____________contractions: when a muscle is not shortening
or lengthening
ex. pushing against an immovable
object
Fatigue
 during muscular exercise:
 b.v. in muscles___________& blood flow and O2
delivery increases
 muscle ___________occurs after extended or strong
muscle contractions and O2 & ATP can’t supply muscle
fibers fast enough
 _______________– amount of O2 taken in to “pay
back” resting metabolic conditions
 if O2 is unavailable, ____________ is converted into
_________ which helps break down glucose for energy
 production of lactic acid in the body causes ________
Concept Check #6
21. List 2 things that can happen when muscles are used irregularly.
22. List 2 things that can happen when muscles are used regularly.
23. How do hypertrophy and hypotrophy (atrophy) differ?
24. Do all the muscle fibers (cells) in my arm contract when I pick up
a pencil? Use the terms threshold stimulus and all or none theory
in your explanation.
Concept Check #7
25. Explain the difference between isotonic and isometric
contractions. Give an example of each.
26. What is the relationship between muscle fatigue and oxygen
debt?
Aging and Pathology of the Skeletal System
• many disorders of the musculature are due to interactions with the
skeletal and nervous systems
Strains vs. Sprains
___________– overworking the muscle’s force on joints and tendons
 pain and swelling of fascia, joints, ligaments, and tendons
 nerves signal pain when stretched or swollen (stiff)
________ – more severe; sudden or violent stress
on a joint/muscle
 ___________of a ligament, muscle, or tendon and
damage to nearby blood vessels
 require ________ for tissue and protein replacement
 To keep swelling down apply _______ 1st
followed by continuous warmth to speed
healing
• _______________ – related to sprains; direct hit(s) to a muscle
Myopathy / Neuromuscular disorders

inability of the nervous system to communicate properly to muscles
1. ____________________– genetic abnormalities of the mitochondria;
muscles can’t produce _______ from food; muscles become easily cramped
2. _____ ______________ – caused by damage to soft tissues @
muscle;_____________growing within muscle tissue; pain
during contraction
3. muscular ______________- involves progressive weakness
in the voluntary muscles; inability of ____________________ to
stimulate muscle action; results in atrophy and wasting
__________________on Muscles
 boost body’s ability to produce ___________________
 prevent muscle breakdown &
______________________________
 resemble chemical structure of
_____________________________
 {T} directs the body to produce
more or enhance male
characteristics (like increased
muscle mass, etc)
Aging of the Muscular System
 natural causes  ______________(muscle loss usually associated with
AIDS, cancer, starvation, anorexia, bulimia); slower form reduces bodies
ability to rebuild muscle structure
 __________________ in neural stimulation -> atrophy
 malnutrition / undernutrition  decrease in carbs and proteins 
______________________and nutrients for repair and maintenance
 __________________________and insulin-like growth factor –1
(IGF-1); needed for muscle cell growth, maintenance, & repair
 physical therapies 
1) artificial up-regulation with _______________________ (causes
muscles to retain protein)
2) muscle _______________________
Concept Check #8
27. What are the differences between strains, sprains, and contusions?
28. Name and describe 2 different types of myopathies.
29. What is cachexia in terms of muscle aging.
30. Describe 4 factors that contribute to muscle aging.
Case Study Investigation
 Selected for an internship at National Space Biomedical Research Ins.
 Required to monitor astronauts for NASA before, during, and after a
space mission.
 American astronaut spent 171 days in the space stations has to go
through 3 weeks of physical therapy.
 She lost 30% of her skeletal muscle even after following all the
exercise programs NASA required. The average is less than 20%.
Questions:
1. Why did the American lose 30% of her skeletal muscle after her
mission to space? Be specific.
2. She lost 10% more than the average astronaut. What else associated
with her mission could have contributed to the American’s muscle
loss?