Chapter 5 - Muscular System Flashcards
What is the muscular system?
This system links the nervous and nervous system and is responsible for generating the forces that MOVE the human body.
Note: Bones help us stand up straight, where as the muscles help us move and attach to the bones via tendons.
What are the 3 types of muscles in the body?
skeletal, cardiac (heart), and smooth (tissues and internal organs)
What is skeletal muscle? What are the primary functions?
The type of muscle tissue that connects to bones and generates the forces that create movement.
Primary functions: Produce movement, support the skeletal system (bones), help with homeostasis by producing heat.
What is the fascia?
The first layer of connective tissue. It surrounds the skeletal muscles and bones.
What is epimysium?
The inner layer of the fascia that directly surrounds the muscle. Also known as “deep fascia”.
What are fascicles?
The largest bundle of fibers that within a muscle. Fascicles are surrounded by perimysium.
What is perimysium?
Connective tissue surrounding a muscle fascicle.
What is endomysium?
Connective tissue that wraps around individual muscle fibers within a fascicle.
What is glycogen?
Glucose (sugar), that is deposited and stored in bodily tissues (like liver and muscle cells). The storage form of carbohydrates.
What is myoglobin?
Protein-based molecule, that carries oxygen into the muscles.
What is myofibrils?
Where contraction of a muscle occurs. They are the contractile components of a muscle cell.
*These are the circles within the muscle fiber.
The myofilaments (actin and myosin) are contained within a myofibril.
What is myofilaments?
The filaments of a myofibril; include actin and myosin.
What is Actin?
A thin myofilament that helps produce muscular contraction.
What is Myosin?
A thick myofilament that helps product muscular contraction.
What is Sarcomere?
The structural unit of a myofibril composed of actin and myosin filaments between two Z-lines. This is the functional unit of the muscular system, this is where muscular contraction occurs.
What is the Z-line?
The meeting point of each sarcomere.
What is neural activation?
The nervous system’s signal that tells a muscle to contract.
The communication link between the nervous system and the muscular system.
What is the neuromuscular junction?
The specialized site where the nervous system communicates directly with muscle fibers.
What is synapse?
A junction or small gap between the motor neuron and muscle cells.
What is a motor unit?
A motor neuron and all of the muscle fibers that it innervates.
What is action potential?
Nerve impulse that is relayed from the central nervous system, through the peripheral nervous system, and into the muscle across the neuromuscular junction.
What are neurotransmitters?
Chemical messengers that cross the synapse between neuron and muscle and assist with nerve transmission.
Essentially, neurotransmitters represent the translation of the nervous system’s electrical message into a form the muscle cells can understand and act on.
What is Acetylcholine (ACh)?
A neurotransmitter used by the neuromuscular system
It helps the action potential cross the synapse into the muscle, which initiates the steps in a muscle contraction.
What is Sliding Filament Theory?
The series of steps in muscle contraction involving how myosin (thick) and actin (thin) filaments slide past one another to produce a muscle contraction, shortening the entire length of the sarcomere.
What is excitation-contraction coupling?
The physiological process of converting an electrical stimulus to a muscle contraction.
What is a power stroke?
The myosin heads bind to actin and pull them toward the sarcomere center, which slides the filaments past each other, shortening the muscle.
What is ATP (Adenosine Triphosphate)?
A high-energy molecule that serves as the main form of energy in the human body; known as the energy currency of the body.
What is resting length?
The length of a muscle when it is not actively contracting or being stretched.
What are Type I muscle fibers?
Muscle fibers that are small in size, generate lower amounts of force, and are more resistant to fatigue.
(Standing up, maintaining posture)
What are Type II muscle fibers?
Muscle fibers that are larger in size, generate higher amounts of force, and are faster to fatigue.
(Physical activities - Running or Jumping)
What is the All-or-nothing principle?
Motor units cannot vary the amount of force they generate; they either contract maximally or not at all.
What are Capillaries?
The smallest blood vessels and the site of exchange of elements between the blood and the tissues.
What is the main difference between Type I and Type II muscle fibers?
Type I - smaller in size, less force produced, slow to fatigue, “slow twitch”, more capillaries, increased oxygen delivery
Type II - larger in size, more force produced, “fast twitch”, fewer capillaries, short-term contractions
