Muscular System The 3 Types of Muscles SKELETAL MUSCLE STRUCTURE.

Slides:



Advertisements
Similar presentations
The Muscular System.
Advertisements

Structure and Function of Skeletal Muscle
Muscular System Chapter 8.
Muscle Function.
Muscular System.
Muscle Physiology.
Skeletal Muscle Contraction
January 9, 2015  Journal: Name three muscles that can be found in your leg.
The Muscular System. Muscular System Functions MOVEMENT MOVEMENT Maintain Posture Maintain Posture Stabilize Joints Stabilize Joints Generate HEAT Generate.
Muscular system SKELETAL MUSCLE Skeletal muscle is made up of hundreds of muscle fibers –Fibers consists of threadlike myofibrils –Myofibrils composed.
MUSCLE TISSUE.
Muscle Fibers. Muscle fiber is the muscle cell Each skeletal muscle contains hundreds to thousands of these fiber cells.
Chapter 9 Muscles and Muscle Tissue
Muscle Structure and Function
OBJECTIVES At the end of this lecture the student should be able to: Define different types of muscles Enumerate cellular organization of human skeletal.
The Muscular System What do skeletal muscles do? How do muscles work?
7.2 Microscopic Anatomy and Contraction of Skeletal Muscle
Muscle Contraction Tendon – cord of dense fibrous tissue attaching the muscle to a bone. Epimysium – the sheath of fibrous connective tissues surrounding.
MUSCLE CONTRACTION. Microscopic Anatomy of Skeletal Muscle Sarcomere Contractile unit of a muscle fiber Figure 6.3b.
The Muscular System Skeletal muscle consists of numerous muscle cells called Muscle fibers. Muscle fiber terminology and characteristics Sarcolemma = plasma.
Lecture # 17: Muscular Tissue
Exercise 14 Microscopic Anatomy, Organization, and
1 Structure of Skeletal Muscle We will begin our look at the structure of muscle starting with the largest structures and working our way down to the smallest.
Skeletal Muscle Tissue Contraction Chapter 10 Anatomy and Physiology Mr. Knowles Liberty Senior High School.
Muscles are made of many individual cells called fibers The Fascia connects the individual fibers to form a muscle and it separates muscles from each.
 Produce skeletal movement  By contraction of muscle fibers  True of all = cardiac, smooth, skeletal  Maintain posture/body position  Some muscles.
Muscle Tissue A primary tissue type, divided into: A primary tissue type, divided into: –skeletal muscle –cardiac muscle –smooth muscle.
Exercise 14 Microscopic Anatomy, Organization, and
Skeletal Muscle Contraction
Dr.Mohammed Alotaibi MRes, PhD (Liverpool, England) Department of Physiology College of Medicine King Saud University.
Muscle Physiology Dynamics of Muscle Contraction MMHS Anatomy.
II. Skeletal Muscle Overview A. Skeletal Muscle Distinguishing Characteristics Striated Voluntary Multi-nucleated B. Functions Movement Maintain Posture.
Three types of muscle Skeletal – attached to bone
Muscular System Notes. Microscopic Muscle Anatomy  Myfibrils  About 1-2 micrometers in diameter  Length of a muscle fiber  Composed of multiple myofilaments.
Anatomy of skeletal muscle ppt #1 Unit 4 Muscles
Outline I. Types of Muscle II. Anatomy of Skeletal Muscle III. Sliding Filament Theory IV. Role of Ca+ in regulating muscle contraction.
Gross Anatomy of Skeletal Muscle
Lecture #21 Date ____ n Chapter 49 ~ Sensory and Motor Mechanisms.
MUSCULAR SYSTEM Structure and Function. Skeletal Muscle Properties 1. Excitability = ability to receive and respond to a stimulus  Also called irritability.
The Muscular System. The characteristics of muscle tissue enable it to perform some important functions, including:  Movement – both voluntary & involuntary.
Muscle voluntary, striated involuntary, striated auto-rhythmic involuntary, non-striated evolved first multi-nucleated digestive system arteries, veins.
Muscle MCQs.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings WHOLE MUSCLE CONTRACTION:PART 1 Motor units All the muscle fibers innervated.
Muscular System Chapter 9. Three types of Muscle Tissue  Skeletal  Smooth  Cardiac.
The Muscular System What do skeletal muscles do? How do muscles work?                      
UNIT 7: MUSCULAR SYSTEM Chapter 9. GENERAL OVERVIEW: STRUCTURE –Hierarchy of skeletal muscles: muscle, fascicles, fibers, myofibrils, myofilaments –Coverings.
MUSCULAR SYSTEM Part 3: Muscle Structure & Contraction.
Structure and Function of Skeletal Muscle. Skeletal Muscle Human body contains over 400 skeletal muscles 40-50% of total body weight Functions of skeletal.
The Muscular System What do skeletal muscles do? How do muscles work?
Muscle contraction.
The Muscular System What do skeletal muscles do? How do muscles work?
Muscles (View Video).
A skeletal muscle is composed of a variety of tissues
Introduction The Muscular System.
Introduction The Muscular System.
“The beginning of wisdom is to call things by their right names.”
The Muscular System.
The Muscular System.
NOTES: The Muscular System (Ch 8, part 2)
The Anatomy of Skeletal Muscle
Arrangement of a Muscle
Muscular System.
Muscle Anatomy and Physiology
Muscle Anatomy.
Muscle relationships and types of contractions
The Muscular System.
Topic 7-3: Skeletal Muscle Fibers
LECTURE 3: Muscular System
The Muscular System Muscle Contractions
7 The Muscular System.
Presentation transcript:

Muscular System

The 3 Types of Muscles

SKELETAL MUSCLE STRUCTURE

– Epimysium (epi = upon) – Perimysium(peri = around) – Endomysium(endo = within) Myo = Muscle Um= Membrane Skeletal Muscle Structure: Connective Tissue Coverings

Skeletal Muscle Structure: Structure Hierarchy 1.Whole Muscle 2.Muscle Facicle 3.Muscle Fiber (cell) 4.Myofibril 5.Filament Largest Smallest

Skeletal muscle fiber (cell) Muscle Fascicle Surrounded by perimysium Surrounded by endomysium Endomysium Perimysium Skeletal muscle Surrounded by epimysium Epimysium Tendon Skeletal Muscle Structure

Microanatomy of a Muscle Fiber (Cell) sarcolemma transverse (T) tubules sarcoplasmic reticulum terminal cisternae myofibril thin myofilament thick myofilament triad mitochondria nuclei myoglobin

I-Band A-Band H- Zone Z-Line M-Line

SARCOMERE

Sarcomere Z line A band H zone I band Zone of overlap M line Zone of overlap Thin myofilaments Thick myofilaments

Muscle fiber myofibril Thin filamentsThick filaments Thin myofilament Myosin molecule of thick myofilament sarcomere Z-line

Sarcomere Structure Striations form a repeating pattern along the muscle fiber called sarcomeres. Z Line – separates sarcomeres. I bands (light bands) are composed of actin filaments attached to Z lines. A bands (dark bands) are composed of myosin overlapping actin attached to Z lines. A central region (H zone) consists of myosin only with a thick line, the M line.

Organization of these protein filaments leads to light and dark striations seen in skeletal muscle under the light microscope which denote each sarcomere.

Z line Thin myofilaments M line Thick myofilaments Z line Myofilaments of Sarcomere

Protein Filaments Myosin: Thick filament of twisted protein strands with globular ends called cross-bridges. Actin: Thin filament protein which can be found in a complex with two other muscle proteins, tropomyosin and troponin.

Thick myofilament ( has ATP & actin binding site)

Thin Myofilament (myosin binding site)

Actin filaments – Has an active sites where it interacts with myosin – Resting – active site covered by tropomyosin which is held in place by troponin Myosin – Head attaches to actin during contraction – Can only happen if troponin changes position, moving tropomyosin to expose active site

Activation of muscles releases calcium which causes troponin to move tropomyosin out of the binding site.

Sliding Filament Theory Myosin heads attach to actin molecules (at binding (active) site) Myosin “pulls” on actin, causing thin myofilaments to slide across thick myofilaments, towards the center of the sarcomere Sarcomere shortens, I bands get smaller, H zone gets smaller, & zone of overlap increases

43 Contraction Cycle Repeating sequence of events that cause the thick & thin filaments to move past each other. 4 steps to contraction cycle Cycle keeps repeating as long as there is ATP available & high Ca+2 level near thin filament

STEP 1 – ATP binds to head of myosin causing it to detachment from actin

STEP 2 – Hydrolysis of ATP (breaks ATP to use energy) – Energy used to “spring load” the myosin head.

Step 2

STEP 3 – attachment of myosin to actin to form crossbridges

STEP 4 – Power stroke!

Myosin and Actin will remain in “expended” state until a new ATP binds the myosin

51 Steps in the Contraction Cycle Notice how the myosin head attaches and pulls on the thin filament with the energy released from ATP

LETS SEE IT IN ACTION