1. Muscular Tissue Skeletal Cardiac Smooth
Muscular (contractile) tissue is composed of cells called muscle fibers.
Muscle fibers contain actin and myosin filaments; interactions result in animal movement.
Three types of vertebrate muscle tissue are:
Skeletal
Cardiac
Smooth

2. Microscopic Anatomy & Physiology
Myofibrils are contractile portions of fibers that lie parallel and run length of fiber.
Protein filaments:
thick (made of myosin)
thin (made of actin)
Sarcomere has repeating bands of actin and myosin that occur between two Z lines in myofibril.
I band contains only actin filaments.
H zone contains only myosin filaments.
Anatomy of skeletal muscle2.ram

4. Sliding Filament Model
As a muscle fiber contracts, sarcomeres within myofibrils shorten.
As sarcomere shortens, actin filaments slide past myosin; I band shortens and H zone disappears.
Sliding filament theory:
actin filaments slide past myosin filaments because myosin filaments have cross- bridges that pull actin filaments inward, toward their Z line.

5. Sliding Filament Model
Contraction process involves sarcomere shortening, filaments themselves remain same length.
ATP supplies energy for muscle contraction.
Myosin filaments break down ATP to form cross- bridges that attach to and pull actin filament.

6. Muscular Contraction
Ca2+ ions bind to troponin, which causes tropomyosin threads to shift position.
Change in structure of tropomyosin exposes myosin heads with ATP binding sites.
The myosin heads function as ATPase enzymes, splitting ATP into ADP + P
After attaching to actin filaments, myosin cross-bridges bend forward, actin filament is pulled along.

7. Muscular Contraction
While ATP and Ca2+ ions are available, cross-bridges attach; as ADP + P are released, the cross-bridges change their positions and cause a power stroke as filaments pull together.
When another ATP molecule binds to myosin head, cross- bridge detaches and the cycle begins again.
When nerve impulses cease, active transport proteins in the sarcoplasmic reticulum pump calcium ions back into storage sites.

9. http://highered. mheducation
apter10/animation__sarcomere_contraction.html

10. Fast twitch & slow twitch muscles
Slow twitch muscle fibers
contract slowly, but keep going for a long time
more mitochondria for aerobic respiration
less SR  Ca2+ remains in cytosol longer
long distance runner
“dark” meat = more blood vessels
Fast twitch muscle fibers
contract quickly, but get tired rapidly
store more glycogen for anaerobic respiration
sprinter
“white” meat

11. Diseases of Muscle tissue
ALS
amyotrophic lateral sclerosis
Lou Gehrig’s disease
motor neurons degenerate
Myasthenia gravis
auto-immune
antibodies to acetylcholine receptors
Stephen Hawking

12. Botox Bacteria Clostridium botulinum toxin
blocks release of acetylcholine
botulism can be fatal
muscle

13. Rigor mortis no life, no breathing no breathing, no O2
no O2, no aerobic respiration
no aerobic respiration, no ATP
no ATP, no Ca2+ pumps
Ca2+ stays in muscle cytoplasm
muscle fibers continually contract
tetany or rigor mortis
eventually tissues breakdown & relax
measure of time of death

14. Signal Transduction Pathway
Fig. 49.2
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15. Sensory reception begins with the detection of stimuli by sensory receptors.
Exteroreceptors detect stimuli originating outside the body.
Interoreceptors detect stimuli originating inside the body.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

16. Sensory Processing Transduction. Amplification. Transmission.
The conversion of stimulus energy into a change in membrane potential.
Amplification.
The strengthening of stimulus energy that is can be detected by the nervous system.
Transmission.
The conduction of sensory impulses to the CNS.
Integration.
The processing of sensory information.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

17. Sensory Receptors Mechanoreceptors respond to mechanical energy.
Pain receptors = nocioceptors.
Different types of pain receptors respond to different types of pain.
Thermoreceptors respond to heat or cold.
Respond to both surface and body core temperature.
Chemoreceptors respond to chemical stimuli.
Electromagnetic receptors respond to electromagnetic energy.
Photoreceptors respond to the radiation we know as visible light.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings