Ch.9: Muscles and Muscles Tissue Part 2 Flashcards
A _______ consist of one motor neuron and all the muscle fibers it innervates or supplies
Motor unit
true or false: when a motor neuron fires (transmit an action potential), all the muscle fibers it innervates contract
True
Contraction where muscle length changes and tension is constant
Isotonic contractions
Contraction where muscle length stays the same yet tension increases
Isometric Contractions
Skeletal muscles are described as voluntary, but even relaxed muscles are almost always slightly contracted
Muscle tone
Three pathways for generating ATP during muscle activity
Direct phosphorylation, Anaerobic pathway, Aerobic pathway
Characteristic of Direct Phosphorylation
Creatine Phosphate and ADP energy source: CP no oxygen use Product 1 ATP per CP 15 Second duration
Characteristic of Anaerobic Pathway (quick money)
Gylcolysis and lactic acid formation energy source: glucose No oxygen use Product: 2 ATP per glucose, lactic acid 30-40 seconds duration
Characteristic of Aerobic Pathway(bank)
Aerobic cellular respiration
energy source: glucose, pyruvic acid, free fatty acid, amino acids
oxygen use required
products 32 ATP per glucose, CO2, and H2O
duration hours
_______ responsible for muscle soreness during intense exercise
lactic acid
______ state of physiological inability to contract even though the muscle still may be receiving stimuli
Muscle Fatigue
For a muscle to return to its resting state all the following must occur
Oxygen reserves in myoglobin must be replenished
lactic acid must be reconverted to pyruvic acid
glycogen stores must be replaced
ATP and creatine phosphate reserves must be resynthesized
Three types of Skeletal Muscle Fibers
Slow oxidative fibers, Fast oxidative fibers, Fast glycolytic fibers
Characteristic of Slow oxidative fibers
contracts slowly, depends on oxygen, high endurance, red
Characteristic of Fast Glycolytic fibers
contracts rapidly, does not use oxygen, depends on glycogen, tires quickly
this type of exercise result in more efficient muscle metabolism and in greater endurance,strength, and resistance to fatigue
aerobic endurance exercise
this type of exercise results to muscle hypertrophy, bulging muscles. strength not stamina is important
resistance exercise
overload principle
forcing a muscle to work hard increases muscle strength
The alternating contraction and relaxarion of these layers mixes substances in the lumen and squeezes them through the organs internal pathways this propulsive action is called
peristalsis
Differences of Smooth muscle myofilaments and Skeletal muscle
thick filaments are fewer but have myosin heads along their entire length
no troponin
thick and thin filaments are arranged diagnolly
intermediate filament- dense body network (anchor)
Special Features of Smooth muscle contraction
- Stress-relaxation response (great volume without causing strong contractions that would expel its content)
- lack of sarcomeres, able to stretch a total range of 150%
- Hyperplasia, divide to increase their numbers
a group of inherited muscle-destroying diseases that muscles initially enlarge due to deposits of fat and connective tissue but the muscle fiber atrophy and degenerate
Muscular dystropy
The most common and serious form is _____ , inherited as a sex link recessive disease. Rarely live beyond their 20s
Duchenne muscular dystrophy
