Anatomy-Muscular System Muscle Types, Characteristics & Function

Bell Work Grab your note taker from the front table Discuss in your groups the anatomical movements at each joint Be ready to demonstrate different anatomical movements!

Objectives Students will be able to: Define terms for muscle types & characteristics Identify muscle types, characteristics & function Label & give examples of muscle types Compare muscle response to USE and DISUSE List skeletal muscle contractions & response to stimulus

Terminology Striated Striped Voluntary Metric Length of muscle Myo Muscle Tendon Connects muscle to bone Contraction Shortening or tensing of a muscle Striated Striped Voluntary Conscious control by will/choice Involuntary Not under conscious control

General Characteristics Muscles provide ACTION for the body Excitable Muscles are electrically excitable Action occurs when nerve cell stimulates the muscle cell Contractable Muscle cells contract Shorten or tense

General Characteristics Extensible Ability to stretch from the normal resting length Elastic Ability to return from a stretch to normal resting length

Muscle Types-Smooth Characteristics Occurs in layers in walls of hollow internal organs Blood vessels, digestive system, urinary system & other internal organs Involuntary

Muscle Types-Smooth Structure Elongated cells with tapered ends Not striated Shorter than skeletal muscle cells

Anatomy-Muscular System Muscle Types-Smooth Function Slower to contract & relax Can maintain longer contraction (endurance) Wave like contractions

Muscle Types-Smooth Smooth Muscle Cells Microscope View Stained

Muscle Types-Smooth Myofibrils Contractile part of muscle fiber Nucleus Hereditary material, controls metabolism Sarcoplasm Protein to control cell metabolism Cell Membrane Surrounds cell Myofibrils Nucleus Sarcoplasm Cell Membrane

Muscle Types-Cardiac Characteristics Occurs only in the heart Involuntary

Muscle Types-Cardiac Structure Striated cells joined end to end Cells interconnected in branching networks Intercalated disks between cells to hold cells together

Muscle Types-Cardiac Function Capable of long contractions Has strength & appearance of skeletal muscle Has endurance of smooth muscle

Muscle Types-Cardiac Cardiac Muscle Cells Microscope View Stained

Muscle Types-Cardiac Striations Stripes Intercalated Disks Branch Striations Stripes Intercalated Disks Separate cells & hold cell together Nucleus Contains hereditary material & controls cell metabolism Nucleus Intercaladed Disks

Muscle Types-Skeletal Characteristics Attached to bone by a tendon Function together with bones to provides movement Voluntary

Muscle Types-Skeletal Structure Striated Cylindrical shape with rounded ends Covered by loose connective tissue called “fascia”

Muscle Types-Skeletal Function Contraction occurs when muscle cell is stimulated by an electro-chemical impulse from a nerve Muscle contracts & moves body part

Muscle Types-Skeletal Skeletal Muscle Cells Microscopic View Stained

Muscle Types-Skeletal Epimysium Connective tissue surrounding muscle Perimysium Connective tissue surrounding bundle of fibers Endomysium Connective tissue surrounding muscle fiber Blood Vessel Perimysium Endomysium Epimysium Bone Tendon

Muscle Types-Skeletal Fascicle Small bundle Muscle fiber Elongated contractile cell Muscle Fiber Fascicle Blood Vessel Endomysium Perimysium Epimysium Bone Tendon

Skeletal Muscle Response to Use Hypertrophy Increase in muscle fiber size Not in # muscle fibers More forceful contraction

Skeletal Muscle Response to Disuse Atrophy Decrease in muscle fiber size Not in # muscle fibers Less forceful contraction

What does that mean? Contraction strength directly related to diameter of muscle fiber The BIGGER the muscle fiber – the more you have used that muscle The SMALLER the fiber – the Less you have used that muscle

3 Types of Muscle Contractions Isometric Muscle contracts but does not shorten Concentric Muscle shortens during contraction Eccentric Muscle lengthens during contraction

Muscle Response Threshold Response Minimal strength of stimulus to get a contraction Muscle remains unresponsive until a certain strength of stimulus is applied

Muscle Response 2. All-or-None Response Muscle fibers are completely relaxed or contracted Stimulus must be threshold strength or greater to get a contraction No Partial Contraction of muscle fibers Either you contract or you don’t!

Muscle Types-Skeletal

Wrap it up… On a sheet of paper… List an example of Smooth muscle Cardiac muscle Skeletal muscle AND give me One characteristic Its structure One function TURN IN ONCE YOU ARE FINISHED! Example: Smooth muscle (give example) Characteristic Structure Function