Unit 2 Chapter 10+11 (Muscle Tissue + System) Flashcards
Where is cardiac muscle tissue located
in the heart
Where is skeletal muscle tissue located
attached to all bones via tendons
Where is smooth muscle tissue located
walls of hollow visceral organs (liver, pancreas, intestines)
Is cardiac muscle tissue under voluntary or involuntary control
involuntary control
Is skeletal muscle tissue under voluntary or involuntary control
voluntary control
Is smooth muscle tissue under voluntary or involuntary control
involuntary control
What are the functions of muscle tissue
-Change chemical energy into mechanical energy to produce movement
-Stabilizes Joints
-Posture
-Generate heat
What are the characteristics of muscle tissue
-Electrical excitability
-Contractility
-Extensibility
-Elasticity
-Amitotic
What is muscle tension
The force generated by the contraction of the muscle
What are the 4 different names individual muscle cells can be referred to as
-Muscle fibers
-Myofibers
-Myocytes
-Muscle cells
What is muscular dystrophy
Progressive weakening of the skeletal muscles
What is muscular hypertrophy
Exercising that makes your muscle’s individual cells increase in only size
What is muscular atrophy
The decrease in size and wasting of muscle tissue
What is aponeurosis
A broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone
How are muscle fibers and connective tissue arranged in skeletal muscle
Muscle fibers are bundled together and wrapped in a connective tissue covering. Each muscle is surrounded by a connective tissue sheath called the epimysium. Fascia, connective tissue outside the epimysium, surrounds and separates the muscles.
How do connective tissue components assist skeletal muscle function
They furnish support and protection for the delicate cells and allow them to withstand the forces of contraction. The coverings also provide pathways for the passage of blood vessels and nerves.
What is muscle origin
A muscle’s proximal attachment; the end of the muscle closest to the torso
What is muscle insertion
A muscle’s distal attachment; the end of the muscle furthest away from the torso
What is the function of the sarcolemma
Plasma membrane of muscle fibers (actively transports substrates into the muscle cell, serves as a docking location for proteins originating in the basement membrane and cytoskeleton, and also transmits neural excitatory impulses that lead to muscle contraction)
What is the function of the T tubule
Maintain the SR calcium store under the tight control of membrane depolarization
What is the function of myofibril
To produce muscle contraction and relaxation.
What is the function of the sarcoplasmic reticulum
stores, releases, and retrieves Ca++
What is the function of the sarcomere
Composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction
What is the function of the Z disc
attachment sites for thin filaments (actin)
What protein component make up thick filaments
Myosin
What protein component make up thin filaments
Actin
What is a synapse
A narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical
signal in the target cell
What are the components of the neuromuscular junction
Synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal
What happens when acetylcholine binds to its receptor
The shape of the entire receptor changes slightly, opening the channel
How do muscle fibers get excited at the neuromuscular junction
Excitation signals from the neuron are the only way to functionally activate the fiber to contract.
What is excitation-contraction coupling
Skeletal muscle being stimulated in order to fire an action potential
What is the sliding filament mechanism
Describes the mechanism that allows muscles to contract
-Myosin binds to actin. The myosin then alters its configuration, resulting in a “stroke” that pulls on the actin filament and causes it to slide across the myosin filament.
What is the cross bridge cycle
The mechanism where the muscle contraction occurs through the sliding of the muscle protein one past another
How do muscle fiber contraction results in body movement
The formation of actin–myosin cross-bridges leads to the sarcomere shortening involved in muscle contraction. These contractions extend from the muscle fiber through connective tissue to pull on bones, causing skeletal movement.
Describe skeletal muscle fiber relaxation
The motor neuron stops releasing its chemical signal, Acetylcholine, into the synapse at the NMJ
What happens when an entire skeletal muscle relaxes
Tropomyosin begins to cover myosin-binding sites
What is a motor unit
The actual group of muscle fibers in a muscle innervated by a single motor neuron
What is a twitch contraction
An involuntary contraction of the fibers that make up a muscle
Describe wave summation
The addition of successive neural stimuli to produce greater contraction
Describe motor unit recruitment
The successive activation of the same and additional motor units with increasing strength of voluntary muscle contraction
What is a cramp
An involuntary contraction of a muscle that occurs suddenly and does not relax, very episodic
Caused by dehydration, prolonged or strenuous exercise
What is a spasm
Occur when your muscle involuntary and forcibly contracts uncontrollably and can’t relax, more general term
What is muscle tone
Low levels of muscle contraction that occur when a muscle is not producing movement
How is muscle tone important to the health of the muscular system
-Allows muscles to continually stabilize joints and maintain posture
-Muscles never fatigue completely, as some motor units can recover while others are active
What is the difference between isotonic and isometric contractions
-In isotonic contractions, the tension in the muscle stays constant, a load is moved as the length of the muscle shortens
-In isometric contractions, the muscle produces tension without changing the angle of a skeletal joint and involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load
What is the difference between concentric and eccentric isotonic contractions
-A concentric contraction involves the muscle shortening to move a load
-An eccentric contraction occurs as the muscle tension diminishes and the muscle lengthens
Which isotonic contraction preferentially stimulate muscle growth and development, concentric or eccentric
Eccentric
What is muscle fatigue
When a muscle can no longer contract in response to signals from the nervous system
What is oxygen debt
The amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction
What are slow oxidative muscle fibers
Muscle fibers that contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP
What are fast glycolytic muscle fibers
Muscle fibers that have fast contractions and primarily use anaerobic glycolysis, fatigue quicker than other muscle fibers
What are the benefits for the body when doing aerobic training
increase stamina, reduce health risks, manage chronic illnesses, clears arteries, boosts mood
What are the benefits for the body when doing anaerobic training
Strengthens bones, Burns fat, Builds muscle, Maintains muscle mass
What are the 3 ways ATP is generated
glycolysis, citric acid cycle, oxidative phosphorylation
What are the 4 sources of ATP that the muscle uses for energy
-Free ATP (low levels circulating freely within muscles)
-Creatine Phosphate
-Anaerobic Glycolysis
-Oxidative Phosphorylation
What is the order of energy sources when using ATP during muscle contraction
Free ATP, Creatine phosphate, oxidative phosphorylation, glycolysis
