practical 2 Flashcards
(235 cards)
Smooth muscle
*resides in the walls of hollow organs
*involuntary/ not striated
*contracts slowly and rhythmically
Cardiac muscle
*involuntary
*own intrinsic contraction rhythm
Skeletal muscle
*make up 40% of body mass
*voluntary
*can contract rapidly, but tires rapidly
upper motor lesion
loss of muscle function as a consequences of strokes damaging neurons in the brain
Excitability
ability of muscle cells (muscle fibers) to respond to stimuli, such as nerve impulses or electrical signals. When stimulated, muscle cells generate action potentials
Contractility
All muscle cells shorten when stimulated
Extensibility
All muscle cells can be stretched, sometimes even more so than their resting lenght
Elasticity
All muscle cells, after being stretched, can recoil to their resting length
skeletal muscle is not _________. (Meaning the muscle does not contract rhythmically)
autorhythmic
What are some functions of muscles?
*generate movement
*Keeps us stationary to maintain posture and balance
*stabilize joints
*generate a lot of heat
tendons connect _______ to _______
tendons connect muscle to bone
when referring to AOI’s, what does the insertion of a muscle imply
the insertion of a muscle refers to the bone or structure that moves
when referring to AOI’s, what does the origin of a muscle imply
the origin of a muscle refers to the bone or structure that is stationary
what is the difference between a direct attachment and an indirect attachment?
direct: the
periosteum/perichondrium is fused with the muscle’s epimysium
indirect: more common, durable, and small (example: tendon). they can blend into the fascia of other muscles to form an attachment
what is a tendon
aka aponeurosis is an example of an indirect attachment. tendons are mostly collagen and rope-like extensions of a muscle’s connective tissue.
- pass around friction points such as boney projections or joints
two or more muscles often work ___________(against each other)
antagonistically; if one muscle is contracting, the other is extending
true or false: skeletal muscle fibers are very large, and multinucleated
true
the sarcolemma of a muscle is known to be the cell ____________; while the sarcoplasm is the ___________
membrane; cytoplasm
_____________ are repeating units of myofibrils, which are themselves repetitive units of skeletal muscle
sarcomeres
sarcomeres display alternating dark __ bands and light __ bands
A; I
- A bands contain thick filaments
- I bands contain thin filaments
sarcomere
runs from Z line to Z line
what protein bisects the H zone
myomesin
what is the contractile unit of muscle
sarcomere
what is the area around the z disc with only thin filaments
light I band