Muscle Tissue Flashcards
can shorten with force and pull on attachment points
contractility
can stretch or extend
extensibility
can generate electricity
excitability
can recoil back to original position
elasticity
The functional unit of skeletal muscle is called a
sarcomere
Human muscles are powered by _____________, which is generated in the body through _______________.
ATP; cellular respiration
______________ muscle is a voluntary muscle that usually connects two bones, _____________ muscle is an involuntary, fatigue-resistant muscle found exclusively in the heart, and ______________ muscle is an involuntary muscle found in viscera (internal organs).
skeletal; cardiac; smooth
Which of the following is NOT a function of muscles in the human body?
movement
posture
balance
generating heat
all of the above are functions of muscles in the human body
In order for actin and myosin to be able to carry out their function, ______________ must first rush into the cell to remove the molecule that normally blocks them from grabbing and sliding across each other.
calcium
The specific neurotransmitter that sends the signal from a motor neuron to muscles is
acetylcholine
The generic name for a protein that transmits a neuron’s signal from one neuron to another, or from a neuron to a muscle fiber (muscle cell) is called
a neurotransmitter
The ion that depolarizes (flips the electric charge) of a muscle cell is _____, and the ion that repolarizes (resets the electric charge) is _____.
Na+; K+
A bundle of muscle fibers (muscle cells) is called a ________________.
fascicle
The neurons that carry the signals from the brain to effectors, such as muscles, to carry out their effects, such as movement, are called ______________
motor neurons
The site at which the nerve and muscle come together is called the
neuromuscular junction
Muscle contractions in which a muscle is flexed without moving (like when holding a textbook straight out in front of you) are called _____________ contractions.
isometric
Activating more and more motor units in a muscle to reach the required strength for a given task is called
recruitment
Isotonic muscle contractions in which the muscle is lengthening while contracting (like when slowly extending your arm to put something down gently) are called ______________ contractions.
eccentric
A group of muscle fibers innervated by the same motor neuron are called a
motor unit
In order for a muscle to have optimal contraction when needed, the sarcomeres should be _____________ at rest.
at their optimal length
_______________ is the constant state of partial muscle contraction maintained by the central nervous system. _______________ is when the muscles are more flaccid and weak than they should be and ______________ is when they are too rigid, spastic, and overactive.
muscle tone; hypotonia; hypertonia
Which of the following performance enhancing substances is NOT correctly paired with its effect?
creatine: increases muscle mass and endurance
Burst activities, like sprinting, use anaerobic _____________ fibers, while high endurance activities like marathons or posture use aerobic _____________ fibers, and the ____________ fibers fall in between for activities like walking.
fast glycolytic; slow oxidative; fast oxidative (intermediate)
Endurance exercise triggers all of the following EXCEPT:
angiogenesis (new blood vessel formation)
more mitochondria in the muscle cells
the formation of more muscle cells (hyperplasia)
more myogloben in the muscle cells
the formation of more muscle cells (hyperplasia)
Resistance (strength) training triggers all of the following EXCEPT:
formation of more muscle cells (hyperplasia)
increase in tendon strength
increase in bone density
increase in muscle cell size (hypertrophy)
the formation of more muscle cells (hyperplasia)
Which of the following is NOT true regarding cardiac muscle cells?
They are autorhythmic, meaning they can initiate contractions without outside influence
They have multiple nuclei due to multiple stem cells fusing during their formation
They are highly fatigue resistant due to a high number of mitochondria and myoglobin
They have intercalated discs with gap junctions that allow large sections of muscles to contract together as one
They have multiple nuclei due to multiple stem cells fusing during their formation
Skeletal and cardiac muscle heal through
scarring and fibrosis
In cardiac muscle, the desmosomes function to
prevent the cells from pulling apart
Smooth muscle heals through
hyperplasia
new cell formation
regeneration via stem cells called pericytes
all of the above
Which of the following is NOT true regarding smooth muscle cells?
They are present in internal organs, such as blood vessels, the intestines, the eyes, and the bladder
They do not have a neuromuscular junction
They are composed of functional units called sarcomeres
They can increase in size due to an increase in the number or cells or size of the cells.
They are composed of functional units called sarcomeres
Smooth muscle contractions can be stimulated by
the autonomic (automatic/involuntary) nervous system
hormone stimulation (ligands)
stretching (mechanoreceptors)
built-in pacesetter cells
all of the above
Identify the two types of myrofilaments
actin and myosin
Identify the 2 molecules that Ca2+ moves out of the way to expose the binding sites on actin:
troponin and tropomyosin
The ___________ is defined as the region between two z-lines
sarcomere
Identify 3 sources of ATP for muscle contraction:
creatine phosphate, glycolysis aerobic, respiration
Identify 2 possible causes of muscle fatigue
Lack of ATP;Lactic acid buildup affecting pH and enzymes;Na+ and K+ imbalances from repeated use; sarcoplasmic reticulumand/or sarcolemma damage affecting Ca2+ regulation
