Chapter 8 Flashcards
Fibrous connective tissue covering muscles
Fascia
How many muscles do we have
600
Add muscles to bone
Tendons
Sheet of connective tissue which attaches muscles to muscle
Aponeurosis
Single muscle cell
Muscle fiber
Fibers made out of proteins myosin (thick) and actin (thin) that plays a role
Myofibrils
What produces striations?
Myofibrils
Connection between motor neuron and muscle fiber
Neuromuscular junction
Motor neuron and muscle fibers it controls
Motor unit
Neurotransmitter that stimulates a skeletal muscle fiber
Acetylcholine
Steps for stimulus for contraction
Muscle impulses signals the release of calcium ions
Linkages form between actin and myosin and muscle fibers contract
Acetylcholine is decomposed by enzyme acetylcholinesterase
Calcium ion transported back
Linkages between actin and myosin break and muscle fiber relaxes
What is the energy source for contraction
ATP
Red pigment in blood that carries oxygen
Hemoglobin
Reddish brown pigment, only found in muscles that carries oxygen
Myoglobin
What is the advantage of having hemoglobin and myoglobin in the same place
This reduces muscle requirement for continuous blood supply
How does lactic acid form
During strenuous exercise, oxygen deficiency may cause lactic acid to accumulate in muscles
Amount of oxygen liver requires to convert lactic acid to glucose and to restore ATP and creatine phosphate
Oxygen debt
3 causes of muscle fatigue
Caused by lactic acid, poor blood supply, or lack of acetylcholine in motor neurons
Minimal strength required to cause contractions
Threshold stimulus
Recording of an electrically stimulated muscle
Myogram
Single contraction that lasts only a fraction of a second
Twitch
Delay between time stimulus was applied and time muscle responded
Latent period
Increased force of contraction by a muscle when twitches occur so rapidly that next twitch occurs before previous one relaxes
Summation
Forceful, sustained contraction without even partial relaxation
Tetanic contraction ????
Explain process of recruitment of motor units
Increase in # of motor units being activated as more motor neurons respond to higher stimuli
As stimulus increases, requirement of motor units continue until all possible units are activated and muscle contracts with maximum tension
Summation and recruitment together can produce sustained contraction of increasing strength
Sustained contractions
When a muscle is a rest, some sustained contraction occur
Muscle tone
Name 2 types of smooth muscle and differ them
Multiunit smooth muscle- fibers separated and less organized found in iris of eye and walls of blood vessels, contract only in respond to stimulation from motor nerves
Lisceral- sheets of cells in close contact, follow in walls of hollow organs, can stimulate each other and cause repeated contractions=rhythmically
Wavelike motion occurring in intestines to force contents along
Peristalsis
Immovable end of the muscle
Origin
Moveable end of the muscle
Insertion
Provides most of the movement
Prime mover (agonist)
Assist the prime mover
Synergists
Resists action of prime mover
Antagonists
Criteria they use in naming muscles (6) q
Size, shape, location, action, # of attachments, and direction of fibers
Factors that limit endurance
Loss of muscle glycogen Loss of fat reserves Low level of blood sugar Lack of oxygen Accumulation of lactic acid (lack of oxy) Heat build up in muscles
3 types of muscle fuel
Carbohydrates-primary fuel
Fat-secondary fuel
Protein- never be a source of fuel
Hitting the wall
When muscles run out of glycogen and become uncoordinated and hurt
Depletion
Your muscles will learn to store more fuel if their supply is used up frequently
Carbohydrate packing
Limit carb in take for three days, then next 3 days eat many carbs
Bonking
Body runs out of liver glycogen, blood sugar drops, brain can’t function properly
Similarities and differences between smooth and skeletal q
Smooth lacks striations; skeletal has them
BOTH contain actin and myosin; BOTH make contractions happen
Smooth-2 neurotransmitters(acetylcholine and norepinephrine); skeletal only one (acetylcholine)
Smooth-contracts slower but maintains contraction longer than skeletal
Similarities of cardiac and smooth
Similarities of cardiac and skeletal
- Involuntary and have myosin and actin
2. Composed of striated cells
From smallest to largest name structure of skeletal muscle
Thick and thin filaments, Myofibrils, muscle fibers, fascicles, muscle
