Muscle Tissue and Organization Flashcards
Why are muscles considered organs?
they are composed of muscle, epithelial, connective, and nervous tissue
What do muscles convert?
chemical energy into physical energy
Types of muscle tissue
skeletal, smooth, and cardiac
typically voluntary muscle tissue
skeletal
typically involuntary muscle tissue
smooth and cardiac
Is essential for propelling materials through our internal tubes (i.e. peristalsis)
smooth muscle
is essential for the pumping of blood (found only in the walls of the heart)
cardiac muscle
specific characteristics ALL muscle cells exhibits
Excitability, Contractility, Elasticity, and Extensibility
another name for muscle cells
muscle fibers
muscle fiber property which means it responds to electrical stimuli
Excitability
muscle fiber property which means it contracts to move bones or propel materials inside the body
Contractility
muscle fiber property which means the muscle cell will recoil to its resting length when the applied tension is removed
Elasticity
muscle fiber property which means a muscle cell is capable of extending in length in response to the contraction of opposing muscle cells
Extensibility
length of a single muscle fiber
as long as the muscle itself
hypertrophy
increase in muscle fiber size (not number)
often follows regular exercise
hypertrophy
Functions of skeletal muscle tissue
- Body Movement (using bones as levers)
- Maintenance of Posture (stabilize joints for upright position)
- Temperature Regulation
- Storage and Movement of Materials (sphincters vs. orifices)
- Support by Stabilizing the Body Walls (prevent displacement of internal structures)
When a student falls asleep in lecture hall, muscular control of the bones and joints is lost, allowing the head to droop forward and the temporomandibular joint to become depressed. Which function of skeletal muscle tissue is absent in this situation?
Maintenance of Posture
Gross anatomy of skeletal muscle includes:
muscle attachments, blood vessels, and nerves
At the ends of a muscle the connective tissue layers merge to form a fibrous cordlike ______, which typically attaches to bone.
tendon
Sometimes the tendon forms a thin, flattened sheet, called an _______. (Greek for “from sinew”)
aponeurosis
which characteristic does a tendon share with a muscle cell?
tendons have some elasticity
the less moveable attachment of a muscle. where does it typically lie?
the origin, which typically lies proximal to the insertion
the more moveable attachment of a muscle. where does it typically lie?
the insertion, which typically lies distal to its origin
Why are skeletal muscles classified as voluntary?
they are controlled by the Somatic (voluntary) Nervous System
the neurons (nerve fibers) that stimulate muscle contraction and innervate muscle fibers within the muscle
motor neurons
neurons that travel away from the center of activity (which is the CNS). another term for motor neurons
efferent neurons
muscle fibers will do this if they are not periodically stimulated to contract by motor neurons
atrophy (waste away)
atrophy
to waste away muscle fibers
the long extension of each motor neuron that transmits a nerve impulse to a muscle fiber
axon
where does the axon travel through?
the fibrous coverings of the muscle
sends impulses to the brain and spinal cord about the activity of the muscles
sensory neurons
neurons that travel towards the CNS. another term for sensory neurons
afferent neurons
bundles of muscle fibers lie parallel to each other within each muscle and are termed _____.
fascicles
The organization of fascicles in different muscles varies in these four different patterns.
- Circular muscles
- Parallel muscles
- Convergent muscles
- Pennate muscles
pattern where fascicles are are concentrically arranged around an opening or recess
Circular muscles
Why is a circular muscle also called a sphincter?
because the contraction of the muscle closes off an opening (orifice)
another name for circular muscles
sphincters
an example of a sphincter that is found within the lips and surrounds the opening of the mouth. Why is this so special?
the orbicularis oris muscle, which is the first sphincter of the digestive tract
pattern where fascicles run parallel to its long axis.
parallel muscles