60 terms


surround entire muscle
surrounds bundle
surrounds single fiber
Connective Tissue
stabilizes and supports components of skeletal muscle
Surrounds muscle at each organization level.
How many muscles does the human body contain?
600 (40-50% body weight)
Basic skeletal muscle unit. Capable of force production and shortening. Arrangement of protein filaments and gives straight appearance.
tropomin 1
Holds Actin
tropomin T
hold Tropomyosin
tropomin C
can bind calcium
ATP production through aerobic metabolism
As Sarco Shortens
actin filaments slide over myosin.
Z-lines approach end of myosin filaments
As Sarco relaxes
It returns to original length
Less overlap between actin and myosin
The sliding filament theory
• Formation of cross bridges between actin and myosin filaments.
• Reduction in distance between z-lines or sarcomere "power stroke"
• ATP is required for muscle contraction
o Myosin ATPase breaks down ATP as fiber
Biochemical Proporties
o oxidative capacity
o type of ATPase
Contractile Properties
o maximal for production
o Speed of contraction
o muscle fiber efficiency
Fast Fibers (Type IIx)
• Fast-Twitch Fibers
• Fast- Glycolytic
• Anaerobic
Type IIa Fibers
• Intermediate Fibers
• Fast-oxidative
• Glycolic fibers
• Anaerobic and Aerobic
• Type I fibers
• Slow-Twitch
• Slow-Oxidative fibers
• Always Start first
• Aerobic
• 10% muscle mass lost is between 25-50 years of age
• additional 40% lost between 50-80 years of age
• Also a loss of fibers and gain in slow fibers
• Also due to reduced physical activity
Proprioception & Kinetic sense
• How the body sense where it is in space
• Receptors: Located in the muscles and tendons
• Info from proprioceptors is sent to the brain
Learning Effect
• Ability to repeat a specific motor unit recruitment pattern
• Results in success performance of a skill
• Requires practice
Muscle Spindles
• Located within the skeletal muscle
• 2 functions: monitor stretch and length of muscle
• initiate a contraction when muscle is stretched
Stretch Reflex
• Quickly stretched muscle
• Initiate immediate contraction
• Due to being stretched
Golgi Tendon Organ
• Located in the tendon
• 2 functions: monitor and respond to tension in tendon
• inhibits actin of muscle to prevent injury
o Muscle exerts force without changing length
o Pulling against immovable actions
o Postural muscles
o Dynamic constant external resistance
o Muscle shortens during force production
o Muscle produces force but length increases
The two Principal contractile proteins found in the skeletal muscle are:
Actin and Myosin
The layer of connective tissue that surrounds the outside of the skeletal muscle is called the:
Calcium is stored in the:
Sarcoplasmic Reticulum
The formation of cross bridges in the contractile process in skeletal muscle is initiated by:
Calcium binding to tropomyosin
The motor neuron and all the muscle fibers it innervates are called a motor:
The site where the motor neuron and muscle cell meet is called the:
neuromuscular junction
The breakdown of ATP in muscle is accomplishment via enzyme:
A successful endurance athlete would likely have ________ compared to a sedentary person.
a higher percentage of type I fibers
Type IIx Fibers
are fast glycolytic
Which of the following events in muscle contraction is the FIRST to occur chronologically ?
the innervating alpha-motor neuron has an action potential
Three Parts to the structure of a Neuron:
Cell Body, Dendrites, Axon
Conduct Impulses toward the cell body
long nerve fiber that conducts away from the cell body of the neuron
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Central Nervous System
consists of the brain and spinal cord
the sensory and motor neurons that connect the central nervous system to the rest of the body
This nervous system provides involuntary control over smooth muscle, cardiac muscle, and glands.
Sympathetic Nervous System
a branch of the autonomic nervous system and prepares the body for quick action in emergencies; "fight or flight"
Parasympathetic Nervous System
the division of the autonomic nervous system that calms the body, conserving its energy (Rest and Digest)
Sensory- Somatic Nervous system
Carries information from skin, sensory organs, skeletal muscles, joints, and internal organs to CNS; directs voluntary movements
Motor Division
Initiates contraction of muscles and limb movements
the electrical discharge that travels along a nerve fiber
channels for Na+ open and enters cell
Channels for K+ open and it leaves cell
Cardiovascular system
Transport O2 to tissues and removal of waste (CO2)
Transport nutrients to tissues
Regulation of body temperature
Sinoatrial node
the heart's pacemaker, located in the wall of the right atrium
Atrioventricular node
delays impulse by 1/10 of second, allowing atria to contract before ventricles
Purkinje fibers
rapidly spreads impulse to contract throughout ventricles
Cardiac Output
Q = HR (bmp) × SV (mL) (5-Men) (4.5-Women)
Adaptations due to endurance training
Increased cardiac output during endurance activity
Increased oxygen delivery to skeletal muscle
Increased endurance performance
Adaptations due to weight training
Increased ability to maintain cardiac output against increased BP during weight training
force velocity curve
ability of muscles to produce force w/ increasing velocity. muscle force increases, velocity of contraction decreases