University:
American Career College
Course:
MICR112 | General Microbiology
Academic year:

2019
Views:

243

Pages:

16
Author:

Kelsey Zavala

 Skeletal ◦ Attached to bones ◦ Nuclei multiple and peripherally located ◦ Striated,Voluntary ◦ Smooth ◦ Walls of hollow organs, blood vessels, intrinsic muscles eye, glands, erector pili muscle of the skin ◦ Single nucleus centrally located ◦ Not striated, involuntary, gap junctions in visceral smooth  Cardiac ◦ ◦ ◦ ◦ Heart Single nucleus centrally located Striations, involuntary, intercalated disks Cardiac muscle found in the wall of the heart and in the base of the large veins the empty into the heart. Figure 10–1. Structure of the 3 muscle types. The drawings at right show these muscles in cross section. Skeletal muscle is composed of large, elongated, multinucleated fibers. Cardiac muscle is composed of irregular branched cells bound together longitudinally by intercalated disks. Smooth muscle is an agglomerate of fusiform cells. The density of the packing between the cells depends on the amount of extracellular connective tissue present. Longitudinal Section Transverse Section Smooth Muscle Comparison of Three Muscle Types Structure of Skeletal Muscle: Connective Tissue Covering  Epimysium (upon, outside)  Perimysium (around)  Endomysium (within) Connective Tissue, Nerve, Blood Vessels Endomysium ◦ Surrounds individual muscle fibres ◦ A layer of reticular fibers ◦ Only small – diameter blood vessels and the finest neuronal branches are present within the endomysium. Organization I: Perimysium Perimysium is a thicker connective tissue laye that surronds a group of fibers to form a bundel or fascicle. Fasicles are functional units of muscle fibers that tend to work together to perform a spesific function. Larger blood vessels and nerves travel in the perimysium. Organization II: Epimysium  A sheath of dense connective tissue that surrounds a collection of fascicles that constitutes the muscle.  The major vascular and nerve supply of the muscle penetrates the epimysium. Organization III: Figure 10–3. Cross section of striated muscle stained to show collagens type I and III and cell nuclei. The endomysium is indicated by arrowheads and the perimysium by arrows. At left is a piece of epimysium. Picrosiriushematoxylin stain. High magnification.