The document discusses the three types of muscular tissue: skeletal, cardiac, and smooth. Skeletal muscle is voluntarily controlled and moves bones. Cardiac muscle is only found in the heart and contracts involuntarily. Smooth muscle is located in internal organs and blood vessels and usually contracts involuntarily. Muscular tissue functions to produce movement, stabilize positions, move substances in the body, and generate heat. The properties of excitability, contractility, extensibility, and elasticity enable muscular tissue to function and contribute to homeostasis.

1. MuscularTissue

2. Overview of MuscularTissue
• Types of MuscularTissue
• The three types of muscular tissue *NB*
• Skeletal
• Cardiac
• Smooth
• Skeletal MuscleTissue
• So named because most skeletal muscles move bones
• Skeletal muscle tissue works mainly in a voluntary manner
• Its activity can be consciously controlled
• Skeletal muscles also are controlled subconsciously to some extent
• Ex: the diaphragm alternately contracts and relaxes mostly without
conscious control

3. Overview of MuscularTissue
• Cardiac MuscleTissue
• Found only in the walls of the heart
(Myocardium / Middle layer)
• Action is involuntary
• Contraction and relaxation of the heart is not consciously
controlled
• Smooth MuscleTissue
• Located in the walls of hollow internal structures
• Blood vessels, airways, digestive tract and many other
organs
• Usually involuntary

4. Overview of MuscularTissue
Functions of MuscularTissue
• Producing Body Movements
• Walking and running
• Stabilizing Body Positions
• Posture
• Moving Substances Within the Body
• Heart muscle pumping blood
• Moving substances in the digestive tract
• Generating heat
• Contracting muscle produces heat
• Shivering increases heat production

5. Overview of MuscularTissue
Properties of MuscularTissue
•Properties that enable muscle to function
and contribute to homeostasis
• Excitability
•Ability to respond to stimuli
• Contractility
•Ability to contract forcefully when stimulated
• Extensibility
•Ability to stretch without being damaged
• Elasticity
•Ability to return to an original length

6. Skeletal MuscleTissue
ConnectiveTissue Components
• Fascia
• Dense sheet or broad band of irregular connective tissue that
surrounds muscles
• Epimysium
• The outermost layer
• Separates 10-100 muscle fibers into bundles called fascicles
• Perimysium
• Surrounds numerous bundles of fascicles
• Endomysium
• Separates individual muscle fibers from one another
• Tendon
• Cord that attach a muscle to a bone

7. Skeletal MuscleTissue

8. Skeletal MuscleTissue
Microscopic Anatomy
• The number of skeletal muscle fibers is set
before you are born
• Most of these cells last a lifetime
• Muscle growth occurs by hypertrophy
• An enlargement of existing muscle fibers
• Testosterone and human growth hormone
stimulate hypertrophy
• Satellite cells retain the capacity to regenerate
damaged muscle fibers

9. Contraction and Relaxation of Skeletal Muscle
The Sliding Filament Mechanism
(How muscles contract)
• Myosin heads attach to and “walk” along the
thin filaments at both ends of a sarcomere
• Progressively pulling the thin filaments toward
the center of the sarcomere
• Z discs come closer together and the
sarcomere shortens
• Leading to shortening of the entire muscle

10. Contraction and Relaxation of Skeletal Muscle
(The Sliding Filament Mechanism)

11. Control of MuscleTension
MuscleTone
(Major Factor In Posture)
• A small amount of tension in the muscle due to
weak contractions of motor units
• Small groups of motor units are alternatively
active and inactive in a constantly shifting
pattern to sustain muscle tone (light muscle tension)
• Muscle tone keeps skeletal muscles firm
• Example: Keeps the head from slumping
forward on the chest

12. Control of MuscleTension
Types of muscle contractions
• Isotonic contraction (Movement/Dynamic)
• The tension developed remains constant while the
muscle changes its length
• Isometric contraction (Static)
• The tension generated is not enough for the object to
be moved and the muscle does not change its length

13. Control of MuscleTension

14. Types of Skeletal Muscle Fibers
Muscle fibers contract at different speeds,
and vary in how quickly they fatigue
Muscle fibers are classified into 2 main types
Slow oxidative fibers (SlowTwitch, Red in colour)
• Used in endurance activities
• Good at burning oxygen with Carbohydrates/Fats/Protein to
produce energy within the muscle.Waste product is CO2 & H20
and have a high resistance to fatigue
Fast glycolytic fibers (FastTwitch, White in colour)
• Used in explosive sprint type activities
• Only burn sugar to produce energy within the muscle.Waste
product is Lactic acid and they fatigue quickly

15. (SlowTwitch)
(Fast Twitch)