Transcript Class Topics - Seneca High School

7/17/2015
Title:
Anat & Phys
11/30/06
Objectives:
To learn about the physiology of muscles.
Class Topics
• Review questions
• Review contraction
• Notes
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–
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Relaxation
Energy sources
Isometric and isotonic contractions
Contraction graphs
Do, or do not do. There is no ‘try’.
Yoda
Friday, July 17, 2015 10:53 PM
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Class Assignments
What
•
•
•
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Read 197-212
Muscle Physiology quiz
Contraction assignment
Muscle physiology test
By When
12/4/06
12/4/06
12/4/06
12/8/06
• Due this class period
• Due next class period
• Due in the future
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Review
1.
Sketch a myofibril
–
Label A band, I band, Z line, H zone,
sarcomere, actin, myosin
2. What is the purpose for nuclei in
the muscle cell?
3. What is the purpose for
mitochondria in the muscle cell?
4. What connective tissue covering is
found surrounding each fascicle?
5. What are three proteins are found
in the “thin filament”?
6. What is a 1:10 ratio of motor
neurons to muscle cells used for?
What muscles?
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Muscle physiology quiz
• Topics
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–
–
–
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Organelles
All or none principle
Myofibril anatomy
Neuromuscular junction
Connective tissue coverings
Innervation ratios
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Contraction
step by step
1 Stimulation - acetylcholine released from
motor neuron
2 Muscle fiber stimulation by acetylcholine
& calcium ions are released from the
sarcoplasmic reticulum
3 Calcium ions bind to troponin molecule
4 Troponin molecules change shape causing
tropomyosin to rotate and expose active
sites on the actin molecule
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Contraction
step by step
5 Cross bridges form between actin
(active sites) and myosin filaments
(globular proteins)
6 Actin filaments slide along myosin
filaments (ATP used) due to a swivel
action of myosin globular protein
7 Muscle fiber shortens as contraction
occurs
Wisconsin Online - animation
Texas A&M University - animation
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Relaxation
1 Acetylcholine decomposes and muscle
fiber is no longer stimulated
2 Calcium ions are Actively TransPorted
into sarcoplasmic reticulum
3 Cross bridges between actin and
myosin are broken – troponin is no
longer activated and it (and
tropomyosin) rotates back into
resting position over actin active
sites
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Relaxation (cont.)
4 Actin and myosin slide apart
5 Muscle fiber lengthens and resting
state is reestablished
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Pattern Puzzle
• Put the paragraph on contraction
back together
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From: http://biomedia.bio.purdue.edu/GenBioLM/
GBMuscle/html/myofilaments.html
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Assignment
• In a series (at least 7) of pictures,
draw a representation of contraction
and relaxation.
• Include a written basic overview of
what is occurring in each step.
• 10 pts.
“Don’t tell people how to do things. Tell them what to do and let
them surprise you with their results.”
George Patton
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Energy Sources for Contraction
1 ATP - found on each globular protein
of myosin - 1 or 2 contractions
2 Creatine phosphate - 25 secs. changes ADP into ATP so the body
can use it for energy
3 Other sources
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Other Sources of NRG
• Cellular respiration - using stored
glucose and oxygen to form ATP
– very efficient
• Anaerobic Respiration
– no oxygen
– changes glucose to pyruvic acid and then
to lactic acid - discomfort in muscles
– inefficient energy source
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From: http://www.nismat.org/physcor/energy_supply.html
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Anaerobic Respiration
• Oxygen debt
– oxygen goes toward decomposition of
lactic acid - not respiration
• Muscle fatigue
– too much lactic acid - low pH - no
contraction
• Muscle cramp
– muscle contracts but doesn’t relax
– not enough ATP to move calcium ions
back into SR
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Muscle Tone
• Sustained contraction occurring in
muscle fibers at all times - resting
muscle
• Used for posture, body positioning,
reflexes, and keep body firm
• Lost when a person passes out
– dead weight
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Athletes
• Higher tolerance to lactic acid
• more capillaries in muscles
• More muscle tone
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Contraction types
• Tetanic contractions
– sustained contraction produced by rapid
sequence of stimuli
• Types of tetanus
– 1. Isotonic
– 2. Isometric
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Isotonic
• Produces movement as the muscle
pulls the bone toward a stationary
structure
• ex. Bicep curl
• All movements!
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Isometric
• Produces muscle tensions, but the
muscle does not shorten
• No body movement
• ex. Pushing an immovable object
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Twitch
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Muscle Types
HO “Muscle, Genes, and Athletic Performance”
• Slow twitch
– Type I
• Fast twitch
– Type IIe
– Type IIx
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