The Muscular System Lab 7

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 of a Muscle Fiber (Cell)

Human Body Explorer link SKELETAL MUSCLE Human Body Explorer link

Location Structure Function Skeletal Muscle Location Structure Function Attached to the Long, thin cells (fibers) are: posture, movement, skeleton - striated stabilizes joints - multinucleated - nuclei are in the periphery of the cell The plasma membrane of the muscle fiber

Skeletal Muscle Note multi-nucleation Whole mount, oil immersion

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-bands, I-bands, Sarcomeres, & Sarcolemma

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

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

Intercalated Disc Nucleus Cardiac Muscle Location Structure Function Wall of the heart Cells (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

Branching cells 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. http://news.bbc.co.uk/1/shared/spl/hi/pop_ups/05/health_heart_pictures/html/4.stm

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

Cardiac Muscle Central nuclei Intercalated disk

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. Epithelial Tissue C.T. C.T. Connective Tissue E.T. E.T. C. T. Epithelial Tissue

Location Structure Function Smooth Muscle Location Structure Function Walls of hollow Cells are: move fluids organs - spindle shaped and other contents - have a single nucleus - not striated nucleus

Cells are arranged closely to form sheets. Smooth Muscle Cells are arranged closely to form sheets.

Note cell and nucleus shapes Smooth Muscle Note cell and nucleus shapes

REVIEW Skeletal muscle Cardiac muscle Smooth muscle

Objective 2 Connective Tissue Coverings of Skeletal Muscle

Note that the endomysium surrounds the sarcolemma

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 Axon terminal Motor Neuron Axon Skeletal muscle fiber

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

Neuron Axon Skeletal muscle fiber Axon Terminal

Muscles Origin, Insertion, Action, Innervation

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

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

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

The nerve that acts on the muscle Innervation The nerve that acts on the muscle Musculocutaneous

We have to learn the names and locations of a lot of muscles Now the hard part We have to learn the names and locations of a lot of muscles

Objective 4 Human Muscles

Frontalis Orbicularis oculi Orbicularis oris Occipitalis Sternocleidomastoid Mentalis Buccinator Masseter Trapezius

Splenius capitis Trapezius Levator scapulae Supraspinatus Teres minor Infraspinatus Teres major Teres major Rhomboid minor Infraspinatus Infraspinatus Rhomboid major Latissumus dorsi

External intercostals Longissimus External intercostals (longest) Iliocostalis (most lateral) Semispinalis Spinalis (most medial) (along spine)

Pectoralis minor Deltoid Subscapularis Biceps brachii Biceps brachii Serratus anterior Serratus anterior Pectoralis major Brachialis Internal intercostals External intercostals Brachioradialis

Pronator teres Brachioradialis Flexor carpi radialis Palmaris longus Brachioradialis Flexor carpi ulnaris Supinator Extensor carpi radialis longus Extensor digitorum Extensor carpi radialis brevis Extensor carpi ulnaris Pronator teres

Transverse abdominus Rectus abdominus External oblique Internal oblique External oblique

Directions of the fibers Rectus abdominus Directions of the fibers

Adductors Hamstrings Quadriceps Anterior Anterior deep Posterior Iliopsoas Psoas major Iliacus Gluteus minimus Adductors Adductor brevis Adductor longus Tensor facsiae latae Pectineus Adductor longus Adductor magnus Hamstrings Vastus lateralis Gracilis Rectus femoris Gracilis Semimembranosis Quadriceps Biceps femoris Semitendinosis Sartorius Vastus medialis (Medial) (Lateral)

Extensor digitorum longus Tibialis anterior Extensor digitorum longus Gastrocnemius Tibialis posterior Fibularis longus Fibularis longus Soleus Fibularis brevis Extensor halicus longus Flexor digitorum longus Fibularis brevis

How many of these muscles can you name?

http://www.getbodysmart.com Muscular System http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/dissector/mml/index.htm Click here