Date post: | 23-Dec-2015 |
Category: |
Documents |
Upload: | jemimah-daniels |
View: | 213 times |
Download: | 0 times |
Energy Requirements and Skeletal Muscle Anatomy
Energy Source
ATP-energy source for muscle contraction and relaxation
ATP is provided from cellular respiration (mitochondria)
The energy released from ATP breaks down to ADP
Much of the energy forms heat, which keeps our bodies warm
Cellular Respiration
Anareobic: Lack of oxygen Produces 2 ATP & lactic acid
1 glucose = 2 ATP Occurs in cytoplasm Fast process Inefficient ATP production
Areobic Oxygen present Produces CO2 and H2O & 36 ATP
1 glucose=36 ATP Occurs in mitochondria Slow process Efficient ATP production
Anaerobic
Very important during times of limited oxygen availability
Only occur for a short period of time (2-3 minutes)
Some lactic acid can diffuse out of the cell; the rest can cause short-term (a day or two) muscle pain
Anaerobic respiration is limited by depletion of glucose and buildup of lactic acid
Aerobic
During resting activities & long term exercise (long distance running) fatty acids are used primarily for ATP production
Energy Source
Creatine phosphate-high energy which increases regeneration of ATP
Stores energy that can be used rapidly to maintain adequate amounts of ATP
During inactivity: excess ATP is synthesized into creatine phosphate
During activity: reserves of ATP are used first, then energy stored in creatine phosphate is accessed to produce ATP for muscle contraction
Rigor Mortis
After a person dies ATP is not available, the cross bridges that are formed are not released, causing the muscle to become rigid.
Muscle Terminology
Muscle Twitch = Contraction of entire muscle in response to a stimulus
Threshold = The minimal strength required to cause a contraction
All-or-none response = Muscle fiber contract maximally or not at all. “Charlie Horse”
3 phases to muscle twitch 1. Lag Phase 2. Contraction Phase 3. Relaxation Phase
Phases of Muscle Twitch
Tetanus: When muscles remain contracted without relaxing Tetanus is infection of the nervous system with
the potentially deadly bacteria Clostridium tetani
Excess build up and release of Calcium
Muscle Terminology Continued Muscle Fatigue: Results when ATP is used
faster than can be produced and lactic acid builds up faster than can be removed. Muscle loses ability to contract and relax after prolonged exercise or strain
Muscle Cramp: a sustained involuntary contraction
Oxygen Debt: oxygen is used to create ATP, during exercise you may not have enough oxygen --> this causes Lactic Acid to accumulate in the muscles
Muscle Fatigue
Results when ATP is used faster than can be produced and lactic acid builds up faster than can be removed
ATP levels can fall too low for muscle cells to produce the maximum force of contraction
During extreme fatigue muscles may not be able to contract or relax; Physiological Contracture
Most common type of fatigue is psychological; perception of central nervous system
Oxygen Debt
After intense exercise respiration rates & volume remain elevated
Pays back oxygen debt that occurred during activity Converts lactic acid to
glucose Replenish depleted ATP
and creatine phosphate stores
Replenish oxygen stores in lungs, blood and muscles
Magnitude of oxygen debt depends on the intensity & length of time of exercise and the physical condition of the person
Exercise and training improves the ability to carry out both aerobic and anaerobic respiration
Muscle Terminology
Muscle Tone: Constant tension produced by muscles of the body over long periods of time.
Slow Fibers: Contract slowly and resistant to fatigue. Type I myosin “Dark Meat”
Fast Fibers: Contract quickly and fatigue quickly. Type IIa or IIb myosin “White Meat”
Muscle Memory: Muscle learn and remember contractions and actions “shooting a basketball”
Attachment of Muscles
Two points of attachment of each muscle are its origin and insertion
Origin = the immovable end of the muscle Insertion = the movable end of the muscle when a muscle contracts the insertion is moved
toward the origin Muscle are attached to bone with tendons
Origin and Insertion
Agonist vs Antagonist
Agonist = muscles working together to cause movement Example: Biceps brachii
Antagonist = muscles working in opposition to another muscle Example: Triceps brachii
Types of Muscle Contraction
Isometric Isotonic Concentric Eccentric
Muscular System
Front
Muscular System
Back
Muscular System
Side
Muscles of the Head and Neck