Muscle Fiber Contraction

Slides:

Advertisements

Similar presentations

Types of Muscle, structure and Function

Advertisements

A2 Biology Skeletal muscle

Skeletal Muscle Activity: Contraction

Muscular System Chapter 8.

Sliding Filament Theory

Muscle Physiology Chapter 1.

Fig Myofibrils are surrounded by calcium- containing sarcoplasmic reticulum.

CONTRACTION OF SKELETLAL MUSCLE: SLIDING FILAMENT THEORY

The Sliding Filament Theory. Steps to the Sliding Filament Theory 1.A message originates in the brain and is released to the central nervous system (CNS)

Chapter 24 …. a little anatomy and physiology. Levels of organization in the vertebrate body.

Muscles n Skeletal muscle organization and how it contracts.

Muscular system SKELETAL MUSCLE Skeletal muscle is made up of hundreds of muscle fibers –Fibers consists of threadlike myofibrils –Myofibrils composed.

Learning Objective: To be able to explain the sliding filament theory using appropriate terminology.

Warm-Up 4/8/15 1.What is an autoimmune disorder? 2.What how are LEMS and MG similar? 3.How are LEMS and MG different? Test - Tuesday.

Chapter 9 Muscles and Muscle Tissue

Myofibrils are surrounded by calcium- containing sarcoplasmic reticulum.

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neuromuscular Junction Figure 9.7 (a-c)

Muscle Structure and Function

Sliding Filament Theory

Myosin Myosin is a protein molecule found in the thick filaments. Myosin is a protein molecule found in the thick filaments.

Muscle Physiology.

7.2 Microscopic Anatomy and Contraction of Skeletal Muscle

 Name the following movements: ◦ Increasing angle of joint (ex. Straightening arm) ◦ Moving around longitudinal axis: ◦ Moving a limb away from midline.

MUSCLE CONTRACTION. Microscopic Anatomy of Skeletal Muscle Sarcomere Contractile unit of a muscle fiber Figure 6.3b.

Muscle Cells & Muscle Fiber Contractions

Muscles & Skeleton Locomotion Chapter 50. Muscle structure  Muscle fibers  Single cell with many nuclei  Each fiber has a bundle of myofibrils  Each.

Cardiac Muscle Involuntary –heart only Contracts & relaxes continuously throughout life –Contracts without nervous stimulation! –A piece of cardiac muscle.

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.

IN CLASS NOTES = STEPS OF A MUSCLE CONTRACTION. STEP 1 Calcium ions present Ca+ binds to troponin which makes tropomyosin move out of way for myosin head.

Muscles. Smooth muscle Found in the walls of hollow organs and the blood vessels Lack striations Contain less myosin Cannot generate as much tension as.

Chapter 11 Physiology of the Muscular System. Introduction Muscular system is responsible for moving the framework of the body In addition to movement,

Sensory and Motor Mechanisms – chpt 49-. I. Anatomy & physiology of Muscular system n A. 3 types of muscle tissue –1. skeletal muscle aka striated muscle–

Interaction of thick & thin filaments __________________ –_____________________________________ _____________________________________ –_____________________________________.

____ Chapter 49 ~ Sensory and Motor Mechanisms ( Just focusing on motor mechanisms ) Motor Mechanisms.

Sliding Filament.

Synapse – The site of connection between a neuron and a cell. Neurotransmitter – A chemical released at the neuron’s synapse that communicates with the.

Muscle Physiology Dynamics of Muscle Contraction MMHS Anatomy.

The Sliding Filament Theory

Muscular System Notes. Microscopic Muscle Anatomy  Myfibrils  About 1-2 micrometers in diameter  Length of a muscle fiber  Composed of multiple myofilaments.

The Physiology of Skeletal Muscle Contraction

Neuromuscular Junction and Major Events of Muscle Contraction Quiz Review.

Muscular System The 3 Types of Muscles SKELETAL MUSCLE STRUCTURE.

Lecture #21 Date ____ n Chapter 49 ~ Sensory and Motor Mechanisms.

Molecular Basis of Muscle Contraction Standard 9 h. Students know the cellular and molecular basis of muscle ocntraction,including the roles of actin,

MUSCULAR SYSTEM Structure and Function. Skeletal Muscle Properties 1. Excitability = ability to receive and respond to a stimulus  Also called irritability.

All Exercise Occurs at the Cellular Level So how does a muscle cell work – allowing us to move during exercise?

Muscle Contraction. 1.Acetylcholine (Ach) is released from the axon terminal (nerve) into the synaptic cleft and binds to Ach receptors in the sarcolemma.

Muscle voluntary, striated involuntary, striated auto-rhythmic involuntary, non-striated evolved first multi-nucleated digestive system arteries, veins.

Sarcomere Physiology: Sliding Filament Theory This is pretty exciting!

Muscle System. Root Words 3 Kinds of Muscle Skeletal Smooth (stomach, intestine) Cardiac.

Section Sarcolemma- plasma membrane of a muscle fiber 2. Sarcoplasm- cytoplasm 3. Sarcoplasmic reticulum- smooth ER that stores Ca Myofibrils-

MUSCULAR SYSTEM Part 3: Muscle Structure & Contraction.

Muscle Contraction and the Sliding Filament Theory

Initially Sarcolemma is in the Resting Membrane state

Muscle Contraction and the Sliding Filament Theory

The sliding filament theory

EQ: How do our muscles in our body contract?

Introduction The Muscular System.

Neuromuscular Function

Muscle Contraction.

NOTES: The Muscular System (Ch 8, part 2)

Muscle Contraction and the Sliding Filament Theory

NOTES: The Muscular System (Ch 8, part 3)

Muscles & Motion.

Applied Exercise Physiology

Muscle and Muscle Contraction

Sliding Filament Theory

MUSCULAR SYSTEM Human Systems.

Do now activity #1 What are the 3 types of muscle?

Presentation transcript:

Muscle Fiber Contraction Chapter 9 Section 9.4 -2

Muscle Contraction When muscles contract they are physically shortening. They contract because of nerve impulses sent from our brain.

Remember… Skeletal Muscle Organization Different types of Myofilaments 1. Thick Filaments Made of bundles of protein called MYOSIN 2. Thin Filaments Made of bundles of protein called ACTIN Actin and Myosin bind to each other, causing muscle contraction

Actin Myofilament -THIN Made up of 2 strands of protein (ACTIN) molecules Like 2 strings of beads loosely wound together

Myosin Myofilament - THICK Made up of 2 strands of protein (MYOSIN) molecules 10 x larger than thin myofilament 2 ends Long rod Double-headed globular region

How Myofilaments Contract… Myosin head attaches to actin.

How Myofilaments Contract… Myosin head moves. Heads bend backwards, like flexing hand or wrist Because head is chemically bonded to actin, it makes actin get pulled along with the myosin head as it flexes

How Myofilaments Contract… Result: Actin myofilament SLIDES past myosin myofilament in the direction of flex One myosin head flexes, then another and then another, and essentially “walks” along actin

How Myofilaments Contract… Takes energy from ATP to release myosin head from actin This repositions myosin head for each new flex To “lift foot from actin” regarding walking analogy

Check it out… http://www.mcgrawhill.ca/school/applets/abbi o/quiz/ch10/myofilament_contraction.swf

Sliding Filament Model Z line Muscle tissue that is anchored at one end of EACH actin myofilament Because its anchored, when the actin moves, it drags the z line along with it Area between Z lines = sarcomere

When Muscle is Relaxed… Myosin heads are raised and ready to be attached. But they are unable to bind to actin. They are unable to bind because the myosin head’s attachment site on actin is PHYSICALLY BLOCKED by a protein called tropomyosin.

So Logically… Tropomyosin needs to get out of the way for muscle to contract. To do this, we require a protein called TROPONIN.

Regulating Muscle Contraction Muscle contraction is regulated by calcium ions (Ca2+) in the sacroplasm. Sarcoplasm - muscle fibre cytoplasm. The calcium ion concentration regulates the troponin - tropomyosin complex.

Regulating Muscle Contraction LOW concentration causes tropomyosin to inhibit myosin binding. HIGH concentration causes tropomyosin to get out of the way so binding can occur.

Where does this Ca2+ come from? Sarcoplasmic Reticulum When muscle is stimulated to contract, SR releases Ca2+ into myofilament. When muscle is stimulated to relax, and stop contracting, Ca2+ returns to SR via ACTIVE TRANSPORT.

Sliding Filament Theory Video http://www.youtube.com/watch?v=0kFmbrRJq 4w