The Muscular System Lab 7 REVIEW What are

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) A muscle cell (fiber) is a bundle of myofibrils Myofibrils

Myofibrils of a Muscle Fiber (Cell) Myofibrils Muscle fiber

SKELETAL MUSCLE Human Body Explorer link

Skeletal Muscle Location Structure Function Attached to the skeleton Long, thin cells (fibers) are: - striated - multinucleated - nuclei are in the periphery of the cell posture, movement, stabilizes joints 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 I Sarcomere A

A-bands, I-bands, Sarcomeres, & Sarcolemma I I I A A I I Sarcomeres Sarcolem ma A I Sarcomere

Skeletal Muscle 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

Cardiac Muscle Location Structure Function Wall of the heart Cells (myocytes) are: provide pressure - faintly striated - branching for the circulation 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 Central nuclei Branching cells are in 3 -D; may not be particularly visible in 2 -D 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. E. T. Connective Tissue T. E. C. T. Epithelial Tissue

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

Smooth Muscle Cells are arranged closely to form sheets.

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 Skele tal m uscle fiber Motor Neuron Axon

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

Neuron Axon le mu l a t Ske Axon Terminal sc ber i f le

Muscles Origin, Insertion, Action, Innervation

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

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

Innervation The nerve that acts on the muscle Musculocutaneous

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 Mentalis Sternocleidomastoid Buccinator Masseter Trapezius

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

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

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

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

Transverse abdominus Internal oblique External oblique Rectus abdominus External oblique

Rectus abdominus Directions of the fibers

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

Tibialis anterior Extensor digitorum longus Gastrocnemius Tibialis posterior Soleus Fibularis longus 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/Med. Ed/Gross. Anatomy/ dissector/mml/index. htm Click here