Anatomy Ch.8 Test Review                                                               

1.  Complete the table about the 3 types of muscle tissue:

 2.  List 5 functions of muscle tissue:

     a. Stabilize body position

     b. Regulates organ volume (spincter muscle)

     c. Produces heat to maintain body temperature

     d. Movement of substances w/in the body

     e. Moves the body

    3.  Vocabulary 

     a.  Tendon:  connective tissue that connects muscles to bone

      b.  Epimysium:  connective tissue that surrounds an entire muscle

      c.  Fascicle:  bundles of 10-199 muscle fibers

      d.  Perimysium:  connective tissue that surrounds bundles of 10-100 muscle fibers

      e. Endomysium:  connective tissue that surrounds individual muscle fibers

      f.  Sarcolemma:  plasma membrane that covers each muscle fiber

      g.  Myoglobin:  reddish pigment that stores oxygen until it’s needed by muscles

      h.  Myofibrils: cylindrical structures containing the 2 types of protein filaments

      i.  Sarcomere:  basic functional units of striated muscle fibers; made of  thick & thin filaments

     j.  Intercalated discs:  interconnection that holds cardiac fibers together & contain gap junctions allowing action potentials to spread from fiber to fiber

     k.  Autorhythmicity:  built-in rhythm of heart contraction

     l.  Intermediate fibers:  smooth muscle fibers in addition to thick & thin filaments

     m.  Origin:  end of muscle that attaches to the stationary bone

     n.  Insertion:  end of muscle that attaches to the movable bone

     o.  Belly:  fleshy part of the muscle between origin & insertion

     p.  Prime mover / Agonist:  a muscle that causes a desired action

q.      Antagonist:  muscle that relaxes while the agonist contracxts

     r.  Synergist:  muscles that help the prime mover function more efficiently

     s.  Fixator:  muscles that stabilize the origin of the prime mover

4.  What is muscle atrophy, name 2 causes?

Muscle atrophy is the wasting away of muscles.  It can be caused by lack of use or nerve damage.

5.  What is muscle hypertrophy; what causes it?

Muscle hypertrophy is the increase of muscle fibers.  It’s caused by working out; repeated physical activity.

6.  Muscle Contraction

a.  Thin filaments are attached to _____________.  These filaments are composed mostly of _____________________ molecules.  While thick filaments are composed of _______________ molecules, shaped like intertwined __________________. Z discs, actin, myosin, golf-clubs

b.  Muscle fibers shorten because thin and thick muscle filaments ____________________ through a process called the ____________________________ mechanism.  Overlap, Sliding-Filament  

c.  An electrical signal delivered by a motor neuron to stimulate a skeletal muscle fiber to contract is a ______________________________________________.  Muscle Action Potential

d.  One motor neuron and all the muscle fibers it stimulates is called a __________________________. Motor unit 

e.  Motor neurons excite a skeletal muscle fiber at the ________________________________ synapse between motor neuron and a muscle fiber. First the release of the neurotransmitter ______________________ (_____) occurs, opening ion channels to allow _____________________ ions across the membrane.  Neuromuscular Junction (NMJ), Acetylcholine (ACh), sodium

f.  Contraction can only occur if ___________ attached to the myosin filaments split, allowing a ________________________ to form between the _________________ and __________________.  A _________________ stroke allows the myosin to rotate and slide the thin filament over the thick filament.  The myosin can only detach from the actin when a _______________ binds to it.  Calcium, crossbridge, myocin, actin, power, ATP

g.  Name 2 toxins / drugs that can disrupt NMJ functions, and how?

Botulinum blocks ACh release so muscles can’t contract. 

Plant poison curare causes muscle paralysis by block ACh receptors.

7.  What is Rigor Mortis & what causes it?

Rigor Mortis is muscle stiffness that occurs after death when calcium leaks out and causes myosin to bind to actin and contract without being able to release.

8.  What is muscle tone? 

     Small groups of motor units alternatively contract to keep skeletal muscles firm.

9.  List, describe & compare the 3 sources of ATP

a.  Creatine-phosphate:  an energy-rich molecule in muscles that can hold a phosphate; allows about 15 sec. contraction

b.  Glycolysis:  anaerobic reaction that makes 2 ATP from each glucose; allows about 30-40 seconds of contraction

c.  Aerobic Cellular Respiration:  uses oxygen to make 36 ATP from each glucose; allowing long term muscle contraction

10.  What happens when there isn’t enough oxygen during long term activity? 

During glycolysis, pyruvic acid is converted into lactic acid

11.  List 4 causes of Muscle Fatigue:

     a.  decline in calcium ions

     b.  lack of oxygen

     c. depletion of glycogen

     d.  build-up of lactic acid & ADP

     e.  depletion of creatine phosphate

12.  Following exercise, elevated oxygen is needed through Recovery Oxygen Uptake.  List 3 uses of this oxygen:

     a.  Converting lactic acid back into glycogen

     b.  Resynthesizing creatine phosphate & ATP

     c.  Replace myoglobin’s oxygen

13.  List & describe the 3 types of skeletal muscle fibers:

a.  Slow Oxidative (SO) fibers:  smallest fiber size; have lots of myoglobin & mitochondria; do mostly cell respiration; resist fatigue; ex. postural muscles of neck, back & legs

b.  Fast Oxidative-Glycolytic (FOG) fibers: medium size fibers; can make ATP thru aerobic respiration or by glycolysis; ex. leg muscles that support body, walk & run

c.  Fast Glycolytis (FG) fibers:  white, largest fibers; have the most myofibrils & powerful/ rapid contraction; mostly makes ATP by glycolysis; used for intense short time movement; fatigue quickly

14.  Explain how the ratio of skeletal muscle fibers affects physical performance and how exercise affects skeletal muscle tissue ratios.

     People with high levels of SO tend to excess at endurance activities (running & swimming.)  People with high levels of FG tend to excel at intense short-term activities, like sprinting.

      Endurance activities can slowly cause some FG fibers to transform into FOG fibers.  Strength training and sprinting can increase the size & strength of FG fibers.

15.  What are anabolic steroids?  List 5 side effects of their use.

Anabolic steroids are a hormone that is taken to increase muscle size & strength.  It can cause liver cancer, kidney damage, heart disease, stunted growth, mood swings, atrophy of breast/ uterus, sterility, facial hair, atrophy of testes & baldness.

16.  List the 2 types of smooth muscle tissue & their location.

     a.  Visceral:  sheets that form small artery/vein & hollow organs

b.  Multiunit:  individual fibers w/ their own motor nerve endings; found in the walls of large arteries, airways, internal eye muscles & arrector pili muscles 

17.  What causes loss of skeletal muscle mass after age 30 and what is the skeletal muscle converted into?

     Inactivity causes loss of muscles and it can be converted into fibrous connective tissue and/ or adipose tissue.

18.  List 6 characteristics that correspond to skeletal muscle names; give 2 examples of each.

     a.  Direction; Rectus abdominis & Transversus abdominis 

     b.  Size; Gluteus maximus & Vastus lateralis

     c.  Shape; deltoid & Orbicularis oris

     d.  Action; Tensor fasciae latae & Extensor digitorium

     e.  # of Origins; Triceps brachii & Biceps brachii

     f.  Location; Tibialis anterior & Temporalis

19.  Identify the 46 muscles from the labeled hand-outs.