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Chapter 9 part II
Muscle Contraction, Smooth muscles
19
Anatomy
11th Grade
12/10/2009

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Term
Where does lactic acid go?
Definition
The lactic acid defuses out of the muscles and into the blood stream then it is picked up by the liver, heart, or kidney cells.
Term
When muscle contractile activity reaches 70% what happens?
Definition
  • Muscles start to buldge and compress blood vessels.
  • Oxygen delivery is impared.
  • Pruvic acid is turned into lactic acid.
Term
Define Muscle Fatigue
Definition
Thee muscle is in a state of physiological inability to contract.
Term
4 reasons muscle fatigue happens
Definition
  1. ATP production fails to keep up with ATP use.
  2. There is a realtive deficit of ATP causing contracture.
  3. Lactic acid accumulates in the muscle.
  4. Ionic imbalances are present
Term
Intense Exercise
Definition

Intense exercise produces rapid muscle fatigue with rapid recovery.

  • Na+-K+ pumps cant restore ionic balances fast enough.
Term
Low Intensity Exercise
Definition

Low intensity exercise produces slow developing fatigue.

  • SR is damaged and Ca2+ regulation is desrupted.
Term
Oxygen Debt
Definition

The extra amount of oxygen needed for the restoration processes.

  • oxygen reserves must be replenished.
  • lactic acid must be converted to pyruvic acid
  • glycogen stores must be replaced.
  • ATP and CP reserved must be resythesized.
Term
Heat Production
Definition
  • Only 40% of energy released in muscle activity is useful as work.
  • The other 60% is given off as heat.
  • High heat levels are prevented by radiation of heat from the skin and sweating.
Term
What is the force of contraction affected by?
Definition
  • The number of muscle fibers
  • How bulky the muscle fibers are.
  • Frequency of stimulation
  • Degree of muscle stretch- muscles contract strongest when they are 80-120% of their normal resing length.
Term
How is the speed of contaction determined?
Definition
By speed in which the ATPases split ATP.
Term
3 funtional characteristics of muscle fiber types
Definition
  1. Slow oxidative fibers- contract slowly, have slow acting myosin ATPases and are fatigue resistant.
  2. Fast ovidative fibers- contract quickly, have fast myosin ATPases and have moderate resistance to fatigue.
  3. Fast glycolytic fibers- contract quickly, have fast myosin ATPases and are easily fatigued.
Term
Smooth muscle shape, organization of layers, location, connective tissue.
Definition
  • Spindle shaped
  • Organized into 2 layers→longitudinal and circular.
  • Found in walls of hollow organs.
Term
What is peristalsis?
Definition
Alternating contactions and relaxations of smooth muscles that mix and squeeze substances through the lumen of hollow organs.
Term
Innervation of smooth muscle.
Definition
  • Smooth muscle lacks nueromuscular junctions.
  • Innervating nerves of automonous nervous systems have bullous swellings called varicosities.
  • Varicosities release nuerotransmitters into wide synaptic clefts called defuse juncions.
Term
How is the SR and myofiliments different from the skeletal muscle?
Definition
SR is less developed and lacks a specific pattern relative to myofilaments.
Term
Smooth muscle has no ______, and no_______.
Definition
  1. Visible striations
  2. Sarcomeres
Term
Proportion and organization of myofilaments in smooth muscles.
Definition
  • Thick and then filaments are present
  • The ration of thick to think filaments are much lower than in skeletal muscle.
  • Arranged diagonally causing smooth muscle to contract in a corkscrew way.
Term
Whole sheets of smooth muscle exhibit what?
Definition
Slow synchronized contraction.
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