Anatomy and Physiology 1 Exam 3
Review Questions with Correct Answers
What are the three types of muscle tissue & what are they composed of? -
ANSWERS*Skeletal*
Composed of:
-Parallel, MULTI-nucleated fibers
-Striated due to protein filaments (myosin and actin).
-Surrounded by connective tissue.
*Cardiac*
Composed of:
-Intercalculated discs
-Striations
-Involuntary contractions (autorhythmic).
*Smooth Muscle*
Composed of:
-Non-striated, involuntary.
-Single nuclei.
-Visceral (single unit) smooth muscle found in walls of viscera and the walls of
arteries/veins.
-Smooth muscle fibers (respond to nerve impulses, hormones, and local chemical
factories)
What are the 5 functions of muscle tissue? - ANSWERS1. Producing body movements
2. Stabilizing body positions
3. Regulating organ volume
4. Moving substances within the body
5. Producing heat
Microscopic Anatomy of Striated Muscle Fibers - ANSWERS*Length* - 4-12 inches
*Diameter* - 10-100 micrometers
*Nuclei* - Each fiber has 100+. Number set at birth.
*Hypertrophy*- *Enlargement* of existing fibers. Testosterone promotes further
*enlargement* of muscle fibers.
*Fibrosis* - Replacement of muscle fibers.
*Sarcolemma* - Plasma membrane of a muscle cell
, *Transverse (T) tubules* - Muscle action potentials *travel through the sarcolemma* and
the *T tubules* to quickly spread through the muscle fiber to *ensure that all parts of the
fiber are stimulated at the same time*.
*Sarcoplasm* - Cytoplasm of the muscle fiber. Contains *glycogen* for ATP synthesis
and *myoglobin* (red colored protein that releases oxygen when mitochondria need it to
produce ATP)
*Sarcoplasmic reticulum (SR)* - Fluid-filled system of membranous sacs. End sacs
called *terminal cisterns*. *Calcium stored here in a relaxed muscle fiber and released
during muscle contraction.*
*Myofibrils* aka "little threads" - Contractile organelles in *skeletal muscle tissue*. This
is what gives the *striated appearance*. There are *thin and thick filaments* which are
*involved in the contractile process.*
*Sarcomere* - Basic functional unit of a *myofibril.*
* Z disc* - Separates one sarcomere from the next
*A band* - *Darker* middle part of the sarcomere. Extends *thick filaments* with a zone
of *thin filaments* overlapping on the ends.
*I band* - Lighter part of the sarcomere. Consists of thin filaments and *NO* thick
filaments.
*H zone* - Narrow *center* of the A band. Consists of *thick* but *NO* thin filaments.
*M line* - Supporting proteins that hold the thick filaments together at the *middle of the
H zone.*
*Myosin* - 300 molecules of myosin form a *single thick filament*. Contractile protein
that looks like two golf clubs twisted together.
*Actin* - main contractile protein in thin fi
Neuromuscular junction - ANSWERS*Motor neuron* - Somatic motor neurons *deliver
the electrical signals to muscle tissues for contraction* through a threadlike axon that
extends from the brain/spinal cord to a group of skeletal muscle fibers.
*Motor unit* - Somatic motor neuron with all the muscle fibers that it stimulates.
*Neuromuscular Junction (NMJ)* - *area of contact* between a nerve fiber and the
muscle it supplies.
Review Questions with Correct Answers
What are the three types of muscle tissue & what are they composed of? -
ANSWERS*Skeletal*
Composed of:
-Parallel, MULTI-nucleated fibers
-Striated due to protein filaments (myosin and actin).
-Surrounded by connective tissue.
*Cardiac*
Composed of:
-Intercalculated discs
-Striations
-Involuntary contractions (autorhythmic).
*Smooth Muscle*
Composed of:
-Non-striated, involuntary.
-Single nuclei.
-Visceral (single unit) smooth muscle found in walls of viscera and the walls of
arteries/veins.
-Smooth muscle fibers (respond to nerve impulses, hormones, and local chemical
factories)
What are the 5 functions of muscle tissue? - ANSWERS1. Producing body movements
2. Stabilizing body positions
3. Regulating organ volume
4. Moving substances within the body
5. Producing heat
Microscopic Anatomy of Striated Muscle Fibers - ANSWERS*Length* - 4-12 inches
*Diameter* - 10-100 micrometers
*Nuclei* - Each fiber has 100+. Number set at birth.
*Hypertrophy*- *Enlargement* of existing fibers. Testosterone promotes further
*enlargement* of muscle fibers.
*Fibrosis* - Replacement of muscle fibers.
*Sarcolemma* - Plasma membrane of a muscle cell
, *Transverse (T) tubules* - Muscle action potentials *travel through the sarcolemma* and
the *T tubules* to quickly spread through the muscle fiber to *ensure that all parts of the
fiber are stimulated at the same time*.
*Sarcoplasm* - Cytoplasm of the muscle fiber. Contains *glycogen* for ATP synthesis
and *myoglobin* (red colored protein that releases oxygen when mitochondria need it to
produce ATP)
*Sarcoplasmic reticulum (SR)* - Fluid-filled system of membranous sacs. End sacs
called *terminal cisterns*. *Calcium stored here in a relaxed muscle fiber and released
during muscle contraction.*
*Myofibrils* aka "little threads" - Contractile organelles in *skeletal muscle tissue*. This
is what gives the *striated appearance*. There are *thin and thick filaments* which are
*involved in the contractile process.*
*Sarcomere* - Basic functional unit of a *myofibril.*
* Z disc* - Separates one sarcomere from the next
*A band* - *Darker* middle part of the sarcomere. Extends *thick filaments* with a zone
of *thin filaments* overlapping on the ends.
*I band* - Lighter part of the sarcomere. Consists of thin filaments and *NO* thick
filaments.
*H zone* - Narrow *center* of the A band. Consists of *thick* but *NO* thin filaments.
*M line* - Supporting proteins that hold the thick filaments together at the *middle of the
H zone.*
*Myosin* - 300 molecules of myosin form a *single thick filament*. Contractile protein
that looks like two golf clubs twisted together.
*Actin* - main contractile protein in thin fi
Neuromuscular junction - ANSWERS*Motor neuron* - Somatic motor neurons *deliver
the electrical signals to muscle tissues for contraction* through a threadlike axon that
extends from the brain/spinal cord to a group of skeletal muscle fibers.
*Motor unit* - Somatic motor neuron with all the muscle fibers that it stimulates.
*Neuromuscular Junction (NMJ)* - *area of contact* between a nerve fiber and the
muscle it supplies.
