Chapter 9 Muscles and Muscle Tissue
Objectives:
- Review
the differences between skeletal, cardiac and smooth muscle
- Examine
the gross anatomical features of skeletal muscle
- Explore
the microscopic anatomy of skeletal muscle, and the specific arrangement
of each element in relation to the others
- Explain
the sliding filament theory of muscle contraction
- Describe
the structural arrangement of the neuromuscular junction, and explain the
generation of an action potential across the sacrolemma
- Define
a motor unit, and explain the events of a muscle twitch
- Identify
the graded muscle response, and explain how factors affect graded
responses.
- Define
muscle tone, and discuss in the context of isometric and isotonic
contraction
- Describe
the mechanism through which muscles are supplied with ATP.
- Underscore
the effects of exercise.
- Explain
the muscle disorder, muscular dystrophy.
Review:
I. Comparison of Skeletal, Cardiac and Smooth Muscle
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Skeletal Muscle |
Cardiac Muscle |
Smooth Muscle |
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II. Internal Structure
of a Skeletal Muscle
Skeletal Muscle is
composed of connective tissue and contractile cells
The entire muscle is surrounded by -
Skeletal tissue is made up of-
Each fascicle is surrounded by a
connective tissue later -
III.
Internal Structure of a Fascicle
Within the
fascicle, the third connective tissue layer, the -
All 3 connective
tissue layers bind the muscle cells together, providing strength and support to
the entire muscle. They merge at the ends of the muscle and are continuous with
the ___________.
Muscle Cell
IV.
Internal structure of a skeletal muscle cell (fiber)
Skeletal muscle cells are often
referred to as __________.
Nucleus-
Sarcolemma-
Sarcoplasmic reticulum-
Terminal cisternae-
T tubule-
Triad-
Cytosol-
Mitochondrion-
Myofibril-
V.
Structure of a Myofibril
The myofibril is made of contractile
proteins called __________________.
Two types of
myofilaments
Thin
filaments (made of protein ____________)
Thick
filaments (made of protein _____________)
Arrangement of
Myofilaments
Thick myofilaments form
_____________bands
Thin myofilament form
_______________ bands.
The bands are alternating form
______________________.
A band
I band
During contraction the I
band gets ____________________.
Z line
H zone
During contraction the H
zone gets __________________
M line
Sarcomere-
V.
Review Organizational Levels of a Skeletal Muscle
Bundle within a bundle organization
Pyramid
VII.
Sliding Filament Theory of Muscle Contraction
Components includes
the following:
Thick filaments
Thin filaments
Thick and thin
filaments
ATP
Calcium Ions
6 Step of Cross Bridge Cycling
1. Exposure of Binding site on Actin
2. Binding of Mysoin to Actin
3. Power Stroke of the Cross bridges
4. Disonnecting the Cross Bridge from Actin
5. Re-energizing and repositioning the cross bridge
6. Removal of Calcium Ions
Calcium Pumps
Multiple Cross Bridge Cycles
Mutiple Filaments
Review of the Role of ATP
The Neuromuscular Junction
Definitions
Resting Membrane potential
Action Potential
Depolarization
Role of the Motor Neuron
Overview of Neuromuscular Junction Action
Arrival of Action Potential At Axon
Terminal
Fusion of Synaptic vesicle
Acetylcholine Binds to Receptor Sites
Breakdown of Acetylcholine
Action Potential Propagation
Calcium Release from Terminal
Cisternal
Contraction of Muscle Cell
Contraction of a
Muscle Cell
Motor Unit-
Muscle Twitch
Latent period
Period of contraction
Period of relaxation
Graded muscle responses
Wave Summation
Incomplete tetnus
Complete tetnus
Multiple unit summation
or Recruitment
Treppe
Muscle tone
Isotonic contractions
Isometric contractions
Muscle Metabolism
ATP is regenerated from 3 pathways
Direct phosphorylation
Anaerobic mechanism
(glycolysis and lactic acid formation)
Aerobic mechanism
(aerobic cellular respiration)
Muscle Fatigue
Oxygen Debt
Effect of Exercise on Muscles
Aerobic exercise
Resistance exercise
Disuse atrophy
Overuse injuries
Anabolic Steroids
Muscle Disorder
Muscular Dystrophy