Ch. 6 The Muscular System

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. Case Study Investigation

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

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 _______________ Overview Chapter 6 – The Muscular System

Three types of muscle are found in the human body: a) __________ muscle (slightly striated & involuntary; b) ____________ muscle (striated & voluntary) c) ___________ muscle (non-striated & involuntary) Muscle

____________= muscles that help the prime mover _____________= muscle that produces the opposite movement as prime mover ____________________=muscle responsible for the movement Skeletal Muscle Function 1. Skeletal Movements = pulling on bone (________________________)

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

________________________ _________________ ______________________ ________________ ________________________

adducts upper arm deltoid abducts arm Muscles of the Trunk flex trunk

flexes forearm pronates & supinates flexes elbow extends elbow MUSCLES of the ARM

flexes thigh + lower leg (middle quadricep) (lateral quadricep) (medial quadricep) Vastus intermedius (inner quadricep) plantar-flexes ankles dorsi-flexes ankles plantar-flexes ankles Quadriceps extend the leg

extends thigh (lateral hamstring (middle hamstring) Hamstrings flex the leg adducts thigh (medial hamistring)

1. _____________: stationary bone the muscle attaches to (i.e. zygomatic arch) 2. ______: rest of the muscle (i.e. masseter) 3. ___________: moveable bone the muscle attaches to (i.e mandible) Musculature: Gross Anatomy

_________: Scapula / Humerus _______ Biceps Brachii ______________: Radius ___________ attachs muscle to bone Sacs of synovial fluid btwn tendon & bone for lubrication

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.

5. How do sphincters regulate organ volume? 6. How does the origin and insertion of a muscle differ? How are they involved in muscle movement? 7. Research the origin and insertion for the following muscles: Gastrocnemius: Origin: Insertion: Pectoralis major: Origin: Insertion: Concept Check #2

Skeletal Muscle Structure surrounds ______________ _____________ each _________________ ________ _________________ __________________ Muscle Structure Animation

Microcopic Muscle Cell Structure  skeletal muscle cells are ______________________cells covered with an excitable membrane called the ______________________  ______________ in sarcolemma __________to signals from other cells/environment and ________ the info to muscle cells causing them to contract  cytoskeleton of muscle cells contain myofilaments made up of protein a) thick–__________ b) thin–___________ ___________ _______________ c) titin

 contractile unit of muscle is called a ____________ (thousands in muscle cell) which is surrounded by a ___________________________ (stores/transports _______ for contraction)  Thick & thin myofilaments form an ____________ pattern within sarcomere  gives muscle its ______________ appearance & carries out contraction  chains of sarcomeres form _________________ com/watch?v=f_tZne 9ON7c

Sarcomere Chain  1 sarcomere 

How Do Muscles Contract  contraction occurs when sarcomeres shorten simultaneously 1._________________at the _________________________ (motor neuron meets muscle fiber) Nerve cells release ___________________________ which binds to sarcolemma and allows ___________to cross membrane Flow of ions causes ______ to be released from ______; travels to sarcomere and initiates ____________________ phase o/nmj_flash.html (basic neuromuscular junction animation)

2.Muscle _________________ – takes place inside muscle cell Ca binds to __________; moves it off the actin-binding site on tropomyosin so _____________________________________ ATP provides energy for myosin head to ______thick m.f across thin m.f. (___________________ Z-lines of sarcomere) hill.com/sites/ /student_view0/chapter10/animation__action_po tentials_and_muscle_contraction.html Crash Course in Contraction

unique muscle composition is genetically determined Types of Skeletal Muscle Fibers Feature________________Twitch Fibers (Type I) __________________Twitch Fibers (Type IIb) SizeSmallestlargest Mitochondria____________ amount (get ATP through aerobic processes) ______________ amount (get ATP through anaerobic processes) Color_______________ (high myoglobin content) ________________ (low myoglobin content) Speed of Contractions _____________________________ Resistance to Fatigue ______ (very fatigue resistant)_______ (not fatigue resistant) ActivitiesMaintaining 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 8. List the three membranes of muscle in order from superficial to deep then explain how they each differ. 9. What is the name given to the membrane that surrounds a muscle cell and why is it important? 10. Draw a picture of a sarcomere and label the two different myofilaments. 11. Why is the sarcoplasmic reticulum that surrounds the sarcolemma so important?

Concept Check #4 12. Why is Ca necessary for starting a muscle contraction? 13. Explain the sliding filament theory. 14. Why might marathon runners have more red twitch fibers and sprinters have more white twitch fibers? (i.e. contraction speed, fatigue resistance)

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 #5 15. List 2 things that can happen when muscles are used irregularly. Regularly? 16. How do hypertrophy and hypotrophy (atrophy) differ? 17.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. 18. Explain the difference between isotonic and isometric contractions. Give an example of each.

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 _______ 1 st 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 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 #6 19. What are the differences between strains, sprains, and contusions? 20. Name and describe 2 different types of myopathies. 21. What is cachexia in terms of muscle aging. 22. 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?