Download Muscles, week 1

TOTE THAT BARGE,
LIFT THAT BALE
Human muscles: physiology,
use, disorders, and diseases
Olli 2017
Janice Ott
Mus = little mouse
Sarco = flesh
40-50% body weight
600+ skeletal muscles
Transform chemical energy
(ATP) into mechanical energy
Muscles can only pull,
never push
Functions:
1. Movement
2. Shape
3. Maintain posture
4. Heat
3 Main Types
•  Skeletal
•  Cardiac
•  Smooth
Cardiac Muscle
Smooth Muscle
Skeletal Cardiac
Smooth
Control
Voluntary
Involuntary
Involuntary
Where
Attached to
bones
Heart
Intestines
Blood vessels
Action
Fast.
Must rest
Rapid, steady
pacemaker
Slow.
Stay contracted
Oxygen
Anaerobic
short
Aerobic
Aerobic
Morphology
Striated
Striated
Smooth
Characteristics:
Excitability
Contractibility
Extensibility
Elasticity
Parts
Origin (fixed)
Insertion (movable bone)
usually crosses a joint
shortens muscle
Belly
Connective tissue
endomysium
perimysium
epimysium
tendons (connect muscle to bone)
fascia (connect muscle to muscle)
Blood vessels
Motor units
each muscle has at least
one nerve
Some 4 muscles/1 nerve (fine)
Some 1000 muscles/1 nerve
(gross)
Muscle tone
Constant nerve stimulation
to maintain tone
If no, become flaccid
Micrsoscopic and action
Huge, long cells
Some 30 cm long
A.  Myofibril
1000s/cell
full of myofilaments
thick (myosin)
thin (actin)
B. Sarcoplasmic reticulum
stores calcium ions
C. T tubules
D. Multiple nuclei
E. Many mitochondria
Let’s move a muscle
Sliding filament theory
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
Message from brain
Neuro muscular junction
Neurotransmitter released
Ach attaches to receptors
Message along sarcolemma
Ca++ released from SR
Binds with actin, exposes
Binding site on myosin
9. Filaments pulled together
10. Energy (ATP) releases
11. Everything relaxes
12. Ca++ returns
ATP
Rigor Mortis
Muscles stiffen 3-4 hrs. after death
Peaks at 12 hours
No oxygen, no ATP
No calcium movement
48-60 hours degradation
Curare
Blocks Ach receptors
Only local, not CNS
Treated: rabies, tetanus,
epilepsy, surgery
Animals research
1870s antivivisection laws
Daniele Bovet
1957 Nobel prize
used succinylcholine
for muscle relaxation
Nerve gas
Blocks acetylcholinesterase
Saliva, tears, coughing
Convulsion
Urination, defecation
Asphyxiation: respiratory
Names
Size: maximus, longus
Shape: deltoid, trapezoid
Location: pectoralis, brachia
# of origins: biceps, triceps,
quadriceps
Action: extensor carpii
Main movements:
1. Adduction
2. Abduction
3. Flexion
4. Extension
5. Rotation