Covering, Support, and Movement of the Body
When a suicide victim was found, the coroner was unable to
remove the drug vial clutched in his hand. Explain the reasons for
this. If the victim had been discovered three days later, would the
coroner have had the same diﬃculty? Explain.
Muscle-relaxing drugs are administered to a patient during major
surgery. Which of the two chemicals described next would be a
good skeletal muscle relaxant and why?
Chemical A binds to and blocks ACh receptors of muscle cells.
Chemical B ﬂoods the muscle cells’ cytoplasm with Ca
Michael is answering a series of questions dealing with skeletal
muscle cell excitation and contraction. In response to “What
protein changes shape when Ca
binds to it?” he writes
“tropomyosin.” What should he have responded and what is the
result of that calcium ion binding?
Smooth muscle has some unique properties, such as low energy
usage, and the ability to maintain contraction over long periods. Tie
these properties to the function of smooth muscle in the body.
and Clinical Application
Jim Fitch decided that his physique le± much to be desired, so he
joined a local health club and began to “pump iron” three times
weekly. A±er three months of training, during which he li±ed
increasingly heavier weights, he noticed that his arm and chest
muscles were substantially larger. Explain the structural and
functional basis of these changes.
Related Clinical Terms
inﬂammation) Also known
; a group of conditions involving chronic
inﬂammation of a muscle, its connective tissue coverings and
tendons, and capsules of nearby joints. Symptoms are nonspeciﬁc
and involve varying degrees of tenderness associated with speciﬁc
trigger points, as well as fatigue and frequent awakening from sleep.
Protrusion of an organ through its body cavity wall. May
be congenital (owing to failure of muscle fusion during
development), but most o±en is caused by heavy li±ing or
obesity and subsequent muscle weakening.
pain) Muscle pain resulting from any
Myofascial pain syndrome
Pain caused by a tightened band of
muscle ﬁbers, which twitch when the skin over them is touched.
Mostly associated with overused or strained postural muscles.
disease, suﬀering) Any disease of
A form of muscular dystrophy that is less
common than DMD; in the U.S. it aﬀects about 14 of 100,000
people. Symptoms include a gradual reduction in muscle mass
and control of the skeletal muscles, abnormal heart rhythm,
and diabetes mellitus. May appear at any time; not sex-linked.
Underlying genetic defect is multiple repeats of a particular gene
on chromosome 19. Because the number of repeats tends to
increase from generation to generation, subsequent generations
develop more severe symptoms. No eﬀective treatment.
Acronym for rest, ice, compression, and elevation. ²e
standard treatment for a pulled muscle, or excessively stretched
tendons or ligaments.
A sudden, involuntary twitch in smooth or skeletal muscle
ranging from merely irritating to very painful; may be due to
chemical imbalances. In spasms of the eyelid or facial muscles,
called tics, psychological factors may be involved. Stretching and
massaging the aﬀected area may help end the spasm. A cramp is
a prolonged spasm; usually occurs at night or a±er exercise.
Commonly called a “pulled muscle,” a strain is excessive
stretching and possible tearing of a muscle due to muscle
overuse or abuse. ²e injured muscle becomes painfully
inﬂamed (myositis), and adjacent joints are usually immobilized.
(1) A state of sustained contraction of a muscle that
is a normal aspect of skeletal muscle functioning. (2) An
acute infectious disease caused by the anaerobic bacterium
and resulting in persistent painful spasms of
some skeletal muscles. Progresses to ﬁxed rigidity of the jaws
(lockjaw) and spasms of trunk and limb muscles. Usually fatal
due to respiratory failure.
AT T H E C L I N I C
Let’s continue our tale of Mrs.
DeStephano’s medical problems,
this time looking at the notes made
detailing observations of her skeletal
Severe lacerations of the muscles of the right leg and knee
Damage to the blood vessels serving the right leg and knee
Transection of the sciatic nerve (the large nerve serving most of
the lower limb), just above the right knee
Her physician orders daily passive range-of-motion (ROM) exercise
and electrical stimulation for her right leg and a diet high in
protein, carbohydrates, and vitamin C.
Describe the step-by-step process of wound healing that
will occur in her ﬂeshy (muscle) wounds, and note the
consequences of the speciﬁc restorative process that occurs.
What complications in healing can be anticipated owing to
vascular (blood vessel) damage in the right leg?
What complications in muscle structure and function result
from transection of the sciatic nerve? Why are passive ROM
and electrical stimulation of her right leg muscles ordered?
Explain the reasoning behind the dietary recommendations.
(Answers in Appendix H)