The Muscular System Lab 7

Objective 4 Human Muscles

LOCATION Muscles named for LOCATION Frontalis Infraspinatus Occipitalis Buccinator Mentalis Supraspinatus Latissimus dorsi -Bone -Bone marking -Body region -Location

LOCATIONS Muscles named for ATTACHMENT LOCATIONS Sternocleidomastoid Sternum Clavicle Mastoid Process Iliocostalis Ilium Costals

SHAPE Muscles named for SHAPE Teres minor Rhomboid major Rhomboid minor Trapezius (Trapezoid) Orbicularis oculi (Orb = Circular) Orbicularis oris Rhombus Teres major (Teres = Round)

SIZE Muscles named for SIZE Pectoralis major Pectoralis minor Adductor magnus Adductor longus Adductor brevis Adductor magnus... short

SIZE Muscles named for SIZE (cont.) Gluteus medius Gluteus maximus Gluteus minimus Vastus lateralis Vastus medialis Vast - large Tensor facsiae latae (lata = wide)

External oblique Internal oblique Rectus abdominus Transverse abdominus External oblique DIRECTION OF MUSCLE FIBERS Muscles named for DIRECTION OF MUSCLE FIBERS

NUMBER OF HEADS (ORIGINS) Muscles named for NUMBER OF HEADS (ORIGINS) Biceps brachii

ACTION Muscles named for ACTION Flexor carpi radialis Flexor carpi ulnaris Pronator teres Supinator

OTHER REPRESENTATIONS Masseter “Mass eater” Soleus “Flat sandal” or “Sole fish Sartorius “Taylor’s muscle”

How many of these muscles can you name?

Muscles Origin, Insertion, Action, Innervation

Origin The immovable (or less moveable) bone to which the muscle is attached Biceps brachii Scapula

Insertion The movable bone to which the muscle is attached (The bone that the muscle moves) Biceps brachii Radius

Action Joint movement(s) caused by contraction of the muscle Flexes and supinates forearm

Innervation The nerve that acts on the muscle Musculocutaneous

dissector/mml/index.htm Click here Muscular System

REVIEW What are the four tissue types? Epithelial Connective Muscular Nervous

Objective 1 Types of Muscle Tissue

SKELETAL MUSCLE

Structure of SKELETAL MUSCLE Muscle  Fascicles  Muscle Fibers (cells)  Myofibrils A muscle cell (fiber) is a bundle of myofibrils

Myofibrils Myofibrils of a Muscle Fiber (Cell) Muscle fiber Myofibrils

SKELETAL MUSCLE Human Body Explorer link

Skeletal Muscle LocationStructureFunction Attached to theLong, thin cells (fibers) are:posture, movement, skeleton - striatedstabilizes joints - multinucleated - nuclei are in the periphery of the cell The plasma membrane of the muscle fiber

Skeletal Muscle Whole mount, oil immersion Note multi-nucleation

Striations in skeletal muscle due to sarcomeres

Striations of the myofibrils are seen through the muscle fiber

Striations: A bands & I bands (dark bands) (light bands)

A-bands, I-bands, & Sarcomere A I Sarcomere A

AI A I A I A I AAA III A-bands, I-bands, Sarcomeres, & Sarcolemma Sarcomeres Sarcolemma

Skeletal Muscle Note nuclei on the periphery of the cells (fibers) Longitudinal section, oil immersion Sarcolemma A-band I-band Nuclei Sarcomere

CARDIAC MUSCLE

The heart muscle (myocardium) forms the bulk of the heart. It is arranged in a spiral or circular bundles. Cardiac muscle bundles “Helical heart” model

CARDIAC MUSCLE – Lab notes

Cardiac Muscle LocationStructureFunction Wall of the heartCells (myocytes) are: provide pressure - faintly striated for the circulation - branching of blood - with one (or two) centrally placed nuclei Cells are connected by intercalated discs (gap junctions/desmosomes) Intercalated Disc Nucleus

Heart muscle is made of different cell types that ‘talk’ to each other so the tissue can respond to changing conditions and efficiently pump blood round the body. This image by Patrizia Camelliti and Peter Kohl shows the microscopic architecture of heart muscle, showing the muscle in red closely associated with fibroblast cells in green. Branching cells

Cardiac Muscle Branching cells are in 3-D; may not be particularly visible in 2-D Central nuclei Intercalated disk

Cardiac Muscle Intercalated disk Central nuclei

Cardiac Muscle Intercalated discs

SMOOTH MUSCLE

Smooth muscle is found in the walls of hollow visceral organs. Contractions force fluids and other substances along. Cells are arranged closely to form sheets. Connective Tissue Epithelial Tissue E.T. E.T. C.T. C.T. C. T.

Smooth Muscle LocationStructureFunction Walls of hollowCells are:move fluids organs- spindle shapedand other contents - have a single nucleus - not striated nucleus

Smooth Muscle Cells are arranged closely to form sheets.

Smooth Muscle Note cell and nucleus shapes

REVIEWCardiac muscle Smooth muscle Skeletal muscle

Objective 2 Connective Tissue Coverings of Skeletal Muscle

sarcolemma Note that the endomysium surrounds the sarcolemma

Skeletal Muscle, cs

Skeletal Muscle, cs & ls A muscle fiber is filled with myofibrils Nuclei

Objective 3 Neuromuscular Junction

Reflex Arc N-M junction (Myoneural junction)

Neuromuscular Junction Skeletal muscle fiber Motor Neuron Axon Axon terminal

Motor Neuron AxonAxon Terminal Skeletal muscle fiber Neuromuscular Junction as you will see it under the microscope

Axon Terminal Neuron Axon Skeletal muscle fiber