stabilizes and supports components of skeletal muscle
Surrounds muscle at each organization level.
Basic skeletal muscle unit. Capable of force production and shortening. Arrangement of protein filaments and gives straight appearance.
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
• 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
• Ability to repeat a specific motor unit recruitment pattern
• Results in success performance of a skill
• Requires practice
• Located within the skeletal muscle
• 2 functions: monitor stretch and length of muscle
• initiate a contraction when muscle is 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
The layer of connective tissue that surrounds the outside of the skeletal muscle is called the:
The formation of cross bridges in the contractile process in skeletal muscle is initiated by:
Calcium binding to tropomyosin
A successful endurance athlete would likely have ________ compared to a sedentary person.
a higher percentage of type I fibers
Which of the following events in muscle contraction is the FIRST to occur chronologically ?
the innervating alpha-motor neuron has an action potential
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Peripheral NERVOUS SYSTEM
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
Transport O2 to tissues and removal of waste (CO2)
Transport nutrients to tissues
Regulation of body temperature
delays impulse by 1/10 of second, allowing atria to contract before ventricles
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