Muscle Physiology

Summer Prematriculation Program

Summer 2004

Rahul Dave’

Rdave2@uic.edu

(312) 996-7610

Rm 206 CMW

Muscles act in many organ

systems

Muscles need a signal to contract

Muscle Anatomy

MotorUnit

Nerve branch

Muscle

Main Nerve

SkeletalMuscle

Smooth Muscle

Cardiac Muscle 1

Cardiac Muscle 2

Intercalated Disc

3 Fiber Types

Fuel ATP Fatigues?

Fast White Glyc High Hard

Fast Red Oxid High Medium

Slow Red Oxid Low Easy

Motor Unit Size

Recruitment Order

Use

Fast White Large Third Power Lift

Fast Red Medium Second Jogging

Slow Red Small First Postural mm

Z-disc

H-zone

M-line

A-band I-ban

d

I-ban

d

Sarcomere Structure

Sliding Filament Theory

Brown Tropomyosin

Yellow Troponins

Blue Actin

Black Myosin Head Bind Site

Other Muscle Proteins

Pink Myosin

Smooth Muscle Structure

Muscle Structure

• Describe the hierarchy of organization in muscle

• Distinguish smooth, skeletal and cardiac muscle based on histology

• Understand and rationalize the differences between fiber types

• Know the skeletal muscle sarcomere structure cold.

Nerve-Muscle

Interface

Excitation-Contraction Coupling

Cross Bridge Cycle

Smooth MuscleNerve-Muscle Interface

E-C Coupling (Smooth)

G

Neurotransmitter

SR

IP3 PIP2

Ca2+

Crossbridge Cycle (Smooth)

Muscle Contraction

• Know each step in transmission across the neuromuscular junction

• Know each step in E-C Coupling for striated muscle

• Know each step in the cross-bridge cycle for striated muscle

• Know the differences between smooth and striated (skeletal + cardiac) muscle

Preload and Afterload

Preload

The force (load) a muscle exerts prior to contraction.

Pre-contraction

Afterload

Force muscle exerts during contraction.

After [the start of] contraction

Demonstration

Frank-Starling Law

Force-Velocity Curve

Exercise Physiology

These are all adaptations

• Learning new motor patterns

• Strength exercises: muscle hypertrophy

• Endurance exercises: changes in muscle metabolism

Muscle Diseases

Metabolism• Lactic Acidosis• Glycogen Storage Diseases

Muscle Function• Dilated Cardiomyopathy• Muscular Dystrophy• Malignant Hyperthermia

Neurologic• Hirschsprung’s disease• Myesthenia Gravis• Multiple Sclerosis• Parkinson’s Disease• Polio