Chapter 1: Structure and Functions of the Body Flashcards
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Describe the Macrostructure of Muscles
Large, Visiablestructures
Organs
Skeletal Muscles that contain muscle tissue, connective tissue, nerves, and blood vessels.
Describe Microstructures of Muscles
Connective Muscle Layers:
AKA Schematic of a muscle:
Epimysium ——(the outer layer)
Perimysium ——(surrounding each fasciculus/group of
fibers)
Endomysium—— (surrounding individual fibers)
Where does muscle growth occur on a cellular level?
Adds to Actin and Myosin
What is a sarcomere?
Functional contractile unit of muscle
Primarily made of Actin and myosin
Measured from z line to z line
What are Myofilaments?
Actin & Myosin
Actin
Thin filament
Molecules arranged in double helices
(like DNA)
Myosin
Thick Filament with the cross-bridge heads
pulls z-line toward center of sarcomere and shortening the muscle fiber
What are the 5 phases of the sliding filament theory?
- Resting phase
—Little Ca in Sarcoplasm
— Myosin heads detached
—Tripomyosin covers binding sites on actin - Excitation-Contraction coupling phase
—Ca released from action potential
— Ca binds to Troponin = conformational shift
— Troponin pulls tropomyosin away
— Myosin headds bind to actin - Contraction Phase
—Cocked heads
— Power storke (myosin fires and attches)
—ATP binds to myosin, making to release
— ATP hydrolyzed by ATPase and releases energy
— Back in the cocked position - Recharge Phase
—continues as long as there is Ca, ATP and ATPase - Relaxation phase
— Ca os sequestered, preventing heads from contracting
— CA is pumped (takes energy) back into SR
Motor end plate
The muscle fiber area is innervated by a motor neuron (axonal terminal)
—Muscle site of axonal terminal—
Acetylcholine
Neurotransmitters released by motor neuron NMJ
Action potential
All-or-None principle
Twitch
Summation
Motor Unit
Tetanus
…..
Proprioception
Kinesthetic sense
(aware of where the body is)
Proprioceptors
Specialized sensory receptors that give you the kinesthetic sense
Roles:
——Facilitate activation of muscle contraction
––in between the fibers (parallel)
Golgi Tendon Organs
In series with extrafusal fibers
where the tendon and muscle meet (at the myotendinous junction)
Roles:
Inhibits muscle activation when too heavy
——inhibits motor neurons if force is excessive
–– occurs with resistance training
Muscle Spindle
Stretch Reflex (stretch-shortening cycle, squat before jump)
An important part of an SSC
They tell when a muscle is stretched, deformed muscle, neuron causing the muscle to contract)
What are the primary functions of Cardiovascular functions?
- Transport nutrients
- Removes waste products
- Aids in regulation of:
—Acid Balance
—Fluid Compartments (sweating)
—Temperature
Types of Blood vessels …..
What are the two major functions of the blood?
Transpots O2 form lungs to tissues
Transports CO2 from tissues to lungs
Can regulate acid-bases
Neuromuscular activity is supported through continuous delivery of O2 (and energy yielding nutrients; e.g., glucose) to and removal of CO2 (and other waste products; e.g., H+) from working tissues via_____ and ____ systems
Respiratory and Cardiovascular
What is the purpose of a Sarcoplasmic reticulum and T-Tublules
SR
—Network of tublules
—Calcium
T-Tubules
—AP Propagation
