Download Muscle Notes 1

Anatomy & Physiology B
Muscular System 1
Remember from last Trimester?
• What are the three types of muscle tissue?
• Where are each located?
• Which are voluntary and which are
involuntary?
• Which are striated which are unstriated?
• Which are multinucleated?
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3 Types of Muscle Tissue
• Skeletal muscle
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multinucleated
attaches to bone, skin or fascia
striated with light & dark bands visible with scope
voluntary control of contraction & relaxation
3 Types of Muscle Tissue
• Cardiac muscle
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striated in appearance
involuntary control
Uninucleated
autorhythmic because of built in pacemaker
3 Types of Muscle Tissue
• Smooth muscle
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Uninucleated
attached to hair follicles in skin
in walls of hollow organs -- blood vessels & GI
nonstriated in appearance
involuntary
Structure and Organization
• 600 Human skeletal muscles
• Regional descriptions
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functions of muscle
general anatomy of skeletal muscles
muscle shape and function
coordinated actions of muscle groups
Muscle Tissue
• Alternating
contraction and
relaxation of cells
• Chemical energy
changed into
mechanical energy
What are the functions of Muscles?
• Producing body movements
• Stabilizing body positions
• Regulating organ volumes
• bands of smooth muscle called sphincters
• Movement of substances within the body
• blood, lymph, urine, air, food and fluids, sperm
• Producing heat
• involuntary contractions of skeletal muscle (shivering)
Connective Tissue Components
Connective Tissues of a Muscle
• Epimysium
• covers whole muscle belly
• blends into connective tissue that separates muscles
• Perimysium
• slightly thicker layer of connective tissue
• surrounds a bundle of cells called a fascicle
• Endomysium
• thin layer of areolar tissue surrounding each cell
• allows room for capillaries and nerve fibers
Myofibrils & Myofilaments
• Muscle fibers are filled with threads called myofibrils
• Myofilaments (thick & thin filaments) are the
contractile proteins of muscle
Filaments and the Sarcomere
• A bands Thick and thin filaments overlap each other
in a pattern that creates dark band, six thin filaments
surround each thick filament
• I bands – light bands, contains only thin filaments
• Sarcomeres - compartments separated by Z discs.
I
I
A
Overlap of Thick & Thin
Myofilaments within a Myofibril
Dark(A) & light(I) bands visible with an electron microscope
Thick & Thin Myofilaments
• Supporting proteins (M line, titin and Z disc help anchor
the thick and thin filaments in place)
Thick Filaments : Myosin
• Made of 200 to 500 myosin molecules
• Arranged in a bundle with heads (cross bridges)
directed outward in a spiral array around the
bundled tails
• central area is a bare zone with no heads
Thin Filaments : Actin
• Two intertwined strands of fibrous (F) actin
A Band
Overlap of Thick & Thin Filaments
Striations and Sarcomeres
Relaxed versus Contracted
Sarcomere
• Muscle cells shorten because
their individual sarcomeres
shorten
• pulling Z discs closer together
• pulls on sarcolemma
• Notice neither thick nor thick
filaments change length
during shortening
• Their overlap changes as
sarcomeres shorten
Muscle Tissue Components
Now work with it ……
• Textbook : Read pp. 154 - 162
• Packet
• Fill in p. 2-4 in packet
• Color p. 5
__________________
MYOFILAMENTS
Threadlike Protein that consist of:
ACTIN Light Bands
_________:
MYOSIN Dark Bands provide
____________:
energy for movement
SARCOMERE
__________________
Contractile Units made of Actin and Myosin that make up:
MYOFIBRILS
__________________
Which are Organelles found in
MUSCLE
FIBERS (CELLS)
__________________
Which have a plasma membrane called a
SARCOLEMMA
__________________
“Muscle Husk” which is wrapped in
ENDOMYSIUM
__________________
Which is connective tissue that covers the muscle cell
ENDOMYSIUM
__________________
Which is connective tissue that covers the muscle cell
PERIMYSIUM
__________________
Connective tissue that bundles the muscle fibers together to form a:
FASCICLE
__________________
Structure of bundled muscle fibers; many fascicles are bound
together by a tough connective tissue called
EPIMYSIUM
__________________
Which cover the entire muscle and blends into
TENDON
__________________
Cord of Connective tissue to connect muscle
to bone
APONEUROSIS
__________________
“Sheet of connective tissue
Aponeurosis
• Bicipital Aponeurosis
• Epicranial Aponeurosis
• Palmar Aponeurosis
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Origin and Insertion
• Origin: The place where the fixed end
attaches to a bone, cartilage, or connective
tissue.
• Insertion: The site where the movable end
attaches to another structure.
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Origin and Insertion
The tendon at the non-moving (or
fixed) end is known as the origin.
The tendon at the moving end
is known as the insertion.
Muscles pull by contracting – they cannot
push to produce the opposite movement.
MOTION TERMS
• FLEXION: reduces the angle of the joint
from the anatomical position. Flex elbow
• EXTENSION: movement that returns you
to anatomical position. Extend elbow.
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MOTION TERMS
• ABDUCTION: move body part away from
midline; arm, fingers, thumb
• ADDUCTION: bring back to midline;
arms, fingers, thumb
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MOTION TERMS
• ROTATION: pivot on an axis; shake head
“no”; can rotate head and shoulder
• CIRCUMDUCTION: to draw a circle with
body part; shoulder, head
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MOTION TERMS
• PRONATION (to lie prone is on stomach).
Turn hands downward.
• SUPINATION: refers to arms; want a bowl
of soup, supinate
ANKLE MOTION TERMS
Some terms relate only to certain areas, such as the ankle:
• INVERSION: when sole of foot points inward
• EVERSION: sole of foot points outward.
• DORSIFLEXION: lift up toes
• PLANTARFLEXION: move toes down
Coordinated Muscle Actions
• Prime Mover : agonist, produces most of force
• Synergist : aids the prime mover
• stabilizes the nearby joint
• modifies the direction of movement that occurs
• Antagonist
• opposes the prime mover
• preventing excessive movement and injury
• Fixator
• prevents movement of bone that prime mover
is attached to
Muscle Actions for Elbow Flexion
• Prime mover (agonist) =
biceps brachii m.
• Synergist = brachialis m.
• Antagonist = triceps brachii m.
• Fixator = muscle that holds
scapula firmly in place such as
rhomboideus m.
Definitions
How Muscles are Named?
• Nomina Anatomica
• system of Latin names developed in 1895
• updated since then
• English names for muscles are slight
modifications of the Latin names.
Naming Skeletal Muscles
• Location of muscle – bone or body region
associated with the muscle
• Shape of muscle – e.g., the deltoid muscle
(deltoid = triangle)
• Relative size – e.g., maximus (largest),
minimus (smallest), longus (long)
• Direction of fibers – e.g., rectus (fibers run
straight), transversus, and oblique (fibers
run at angles to an imaginary defined axis)
Naming Skeletal Muscles
• Number of origins – e.g., biceps (two
origins) and triceps (three origins)
• Location of attachments – named according
to point of origin or insertion
(sternocleidomastoid)
• Action – e.g., flexor or extensor, as in the
names of muscles that flex or extend,
respectively (extensor digitorum)
Skeletal Muscle Shapes
Arrangement of Fascicles
• Fusiform muscles
• thick in middle & tapered at ends
• biceps brachii m.
• Convergent muscle
• broad at origin and tapering to a
narrower insertion
• Parallel muscles
• parallel fascicles
• rectus abdominis m.
Skeletal Muscle Shapes (2)
• Circular muscles
• act as sphincters
• ring around body opening
• orbicularis oris m.
• Pennate muscles
• fascicles insert obliquely
on a tendon
• unipennate, bipennate or
multipennate
• palmar interosseus m.,
rectus femoris m. &
deltoid m.
Muscles are Not Boring
Figure 10.4b