Download Skeletal Muscle Mechanics

‫الرحمن‬
‫هللا‬
‫بسم‬
‫ّ‬
‫الرحيم‬
‫ّ‬
Skeletal Muscle Mechanics
By: Dr. Khurram Irshad
OBJECTIVES
To Learn
 Structure of Skeletal Muscle
 How muscle length shortens during the
process of contraction
Muscle Physiology
Contraction Specialists
Helps to maintain Homeostasis
Classification
i.
Types
Skeletal Muscles
40% of
body weight
i.
Smooth Muscle
10% of body
weight
i.
Cardiac Muscles
Classification of Muscles
i.
ii.
Striated
- Skeletal muscles
- Cardiac Muscle
Unstraited
- Smooth muscles
i. Voluntary muscles
- Skeletal muscles
(Innervated by somatic
nerves)
ii. Involuntary muscles
- Smooth muscles
- Cardiac muscles
(Innervated by autonomic nerves)
Structure of Skeletal Muscle
Molecular Basis of Skeletal
Muscle Contraction
Sliding Filament Theory
Cross Bridge Activity
Rise in intracellular calcium ion Concentration
Triggers cross bridge activity
Cross Bridge Cycle
The Tubules and Sarcoplasmic
Reticulum
Simple (Single) Muscle Twitch
Excitation-Contraction Coupling
Skeletal Muscle Mechanics
Muscles can produce contraction/power
of different grades by
1.
2.
The number of muscle fibers contracting
within a muscle.
Tension developed by each contracting
fiber.
The number of muscle fibers
contracting within a muscle
Tension develop by each contracting
fiber

Frequency of stimulation.

The length of fiber at the onset of contraction.

The extent of fatigue.

The thickness of fiber.
Frequency of stimulation
The length of fiber at the onset of
contraction
Source of energy required for skeletal
muscle contraction and relaxation
ATP
Sources:
1.
Stored ATP (only limited stores are available)
2.
Creatine Phosphate (CP)
3.
Oxidative Phosphorylation
4.
Glycolysis.
Fatigue
“Inability of a muscle to maintain a
continuous tension for a prolonged
period of time”
Causes:
i. Muscle Fatigue:
- Accumulation of lactic acid
- Depletion of energy stores
ii.
Central Fatigue:
iii.
Neuro Muscular Fatigue:
Types of Muscle Contraction
There are two types of muscle contraction.
1.
Isotonic
ii. Isometric
Types of Muscle Fibers
-
Slow-oxidative (type I) fibers
-
Fast-oxidative (type IIa) fibers
-
Fast-glycolytic (type IIb) fibers
Thank you