Human Muscles

Types of Muscle Cells Skeletal (Voluntary, Striated) Muscle

these are muscles you control; the ones you exercise.

Smooth (Involuntary, Smooth) Muscle these are muscles you cannot control They work the inner parts of the body (viscera)

Cardiac Muscle (Involuntary, striated) myogenic due to interconnections These muscles of the heart do not get tired.

Types of Muscle Cells

Smooth Muscle Cells

Cardiac Muscle Cells

Skeletal Muscle Cells

Tissues in Skeletal Muscles

1. Skeletal muscle tissue

2. Connective Tissue Components

3. Nervous Tissue

Connective Tissue Components

Endomysium Perimysium

Fascicles Epimysium Tendon

Tendon Pictures

Aponeurosis Also may be formed

from the three fibrous wrappings

may merge with the wrappings of another muscle.

Size and Shape of FibersSize: varies from large to smallShape: varies

Broad: Latisimus dorsi Narrow: Sartorius Flat: Latisimus dorsi Bulky: Gastrocnemius Long: Sartorius Circular: Orbicularis oris Triangular: Deltoid

Shape: Broad Latisimus dorsi

Shape: Narrow Sartorius

Shape: Flat Latisimus dorsi

Shape: Bulky Gastrocnemius

Shape: Long Sartorius

Shape: Circular

Orbicularis oris

Shape: Triangular

Deltoid

Fiber ArrangementArrangement of SMF within the muscle, varies.

Parallel to long axis Converge to narrow attachment Oblique are slanted Pennate – “think feather pen” Bipennate Curved

Parallel to long axis

Horizontal: Transversus abdominis

Vertical

Rectus abdominis

Converge to narrow attachment

Pectoralis major

Oblique are slanted

External oblique

Pennate – “think feather pen” Vastus group

Bipennate “two feathered”

Rectus femoris

Curved

Fibers are circular Orbicularus oris

Attachment of Muscles-Joints Most muscles attach

articulating bones across a joint.

Upon contraction of the muscle, one bone remains in a fixed position and the other moves. Femur

Pelvis

Attachment of Muscles-

Origin

Origin The point of attachment that does not move during

muscle contraction.

Pelvis

Attachment of Muscles-

Insertion

Insertion – the point of attachment that does move when the muscles contract.

Femur

Attachment of Muscles-Contraction

Typically, when a muscle contracts, the insertion is moved closer to the origin.

ROLE OF MUSCLES, BONES, AND JOINTS IN MOVEMENT Lever

any rigid bar free to move around a fixed point called a fulcrum

Lever system Rigid bar - a bone

F = Fulcrum - joint a point around which the rigid bar rotates

L = Load: Weight – resistance something that is moved

P = Pull - Muscle contraction force producing the movement

Muscle GroupsMuscles work

together! Some muscles in a group contract while other relax. Prime mover Antagonist Synergists Fixator muscles

Prime MoverA muscle or group

of muscles which directly performs a specific movement. Flexion of

forearmBiceps brachii is PM

Antagonist When actively contracting, they oppose the movement

of the prime mover. They are relaxed when the

prime mover is contracting. Flexion of forearmT. brachii

is anatagonist

Synergistscontract at the same

time as the prime movers;

they complement the prime movers. Flexion of

forearmbrachialis is synergist

Fixator muscles

usually serve to stabilize joints. They help to maintain balance and posture during the contractions of the prime movers.

Naming of MusclesLocationFunction - named for what they doShape - shape of the muscleDirection of fibers - orientation of fibersNumber of divisions or heads - connectionsPoints of attachment - what bones are

attached to OR bone markingsSize - how big is the muscle relative to

other muscles

Location brachialis - in the arm

Function - named for what they do

Adductor group move leg toward the

midline

Shape - shape of the muscle deltoid - triangular

muscle in the shoulder

Direction of fibers - orientation of fibers rectus abdominus

rectus refers to up and down

Oblique slanting

transversus

Number of divisions or heads – connections

biceps brachii

Points of attachment What bones are

attached to OR bone markings

Sternocleidomastoid

Size

how big is the muscle relative to other muscles Gluteus maximus – in human beings, bigger than

gluteus medius and minimus.