Aparat Cardiovascular

APARAT CARDIOVASCULAR

blood vessels consist of concentric layers or "tunics" of different tissue types

ELASTIC ARTERIES

• In the aorta, the tunica media constitutes the greater part of the vessel wall. It is made up of multiple elastic lamellae alternating with thin layers of circularly oriented smooth muscle . The boundary between the tunica intima and media is not readily defined, and the internal elastic lamina is merely the innermost of the many elastic lamellae within the wall. The tunica adventitia essentially lacks elastic lamellae, and is mainly loose connective tissue and blood vessels (vasa vasorum).

Smooth muscle and elastic fibers make up the tunica media. The elastic tunica intima is not easily defined

ADVENTICEA AORTEI

Medium magnification view of a medium-sized muscular artery. The lumen (L) contains only small amounts of blood cells. The tunica media (TM) is bounded on the inner side by a wavy thick band of elastin, the internal elastic lamina (see higher magnification view). The tunica adventitia (TA) contains a substantial amount of elastin

• Consists of a thick tunica media that consists of smooth muscle and elastin. It is surrounded by a narrow tunica adventitia that is made up of collagen. The tunica intima is a thin layer made up of elastin

Low magnification view of a medium-sized muscular artery (A) and a medium- sized vein (V), stained with an elastic stain. Both vessels run in parallel and are enclosed in fibrous

connective tissue.

• Elastic artery (carotid) and large vein (jugular). • Contrast the artery with the vein . Observe the intima, media, and adventitia. In the artery, the elastic lamellae are readily observed. The aorta compared to the carotid artery has a thicker intima and more elastic lamellae in the media.

Tunica intima faces the lumen. Smooth muscle and elastic fibers make up the tunica media. Underneath is the tunica adventitia made of loose connective tissue.

Aorta, human 40+ years, Verhoeff Van Gieson stain.

that elastic and collagen fibers are easy to visualize in this slide.

Aorta, human new born, Verhoeff Van Gieson stain.

1. Endothelial cell lining 2. Subendothelial layer 3. Internal elastic lamina

Elastin in the form of fenestrated elastic lamellae (esp elastic arteries)

ARTERE MUSCULARE

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In muscular arteries, smooth muscle becomes the predominant constituent of the tunica media. Internal and external elastic laminae are prominent. The tunica intima is thinner than the intima of elastic arteries. Slide 81 Spermatic cord. This slide has several muscular arteries mixed in with atypical veins of the pampiniform plexus . These veins contain a greater amount of smooth muscle than most veins of this size. Also note the outer longitudinal arrangement of smooth muscle in these veins. Observe the characteristic three layers of the arteries present. Note the large amount of circularly arranged smooth muscle in the media of the muscular arteries. Slide 47 Submaxillary gland, Verhoeff's hematoxylin; mucicarmine & methyl green. Find the muscular arteries . Internal and external elastic laminae (or membranes) are stained black and therefore readily observed. Look carefully in the media of the arteries and you should be able to resolve elastic fibers also.

SLIDE 29 • Peripheral arteries, veins, and nerves tend to travel and branch in parallel. Wherever one of these structures is found, the other two are likely to be closeby. • In this specimen, elastic tissue is colored dark purple, cytoplasm (in smooth muscle and nerve) is lighter purple, and collagen is pale pink. The background is adipose connective tissue. • Note differences between artery and vein, most notably the thickness of the vessel wall relative to the lumen. • The intima is not noticable at this magnification (although intimal flaps of a valve are visible in the large vein). • The media is the thickest, most conspicuous layer of the artery, much less pronounced in the vein. • In this loose connective tissue, the adventitia comprises distinct layer.

In this trichrome stained specimen, collagen is colored blue and smooth muscle is red. Red blood cells (RBCs) in the arterial lumen are brighter red. The red texture in the upper-left corner of the image is cross-sectioned smooth muscle in wall of the (unidentified) organ from which this specimen was taken

Col. tricromica

In this trichrome stained specimen, collagen is colored blue and smooth muscle is red. Red blood cells in the venous lumen are brighter red. The background is adipose

connective tissue

Arterial wall, elastin stain

In this specimen, elastic tissue is colored deep purple, collagen is pale pink and cytoplasm (in smooth muscle and nerve) is purple.

ARTERIOLE

The intima of the small artery is visible only as a "dotted line" of nuclei of endothelial cells, exactly at the edge of the arterial lumen. These nuclei look round rather than flat because post-mortem contraction of smooth muscle in the media has caused longitudinal wrinkles in the endothelium

Arteriole, longitudinal section

Because smooth muscle fibers encircle the vessel, when the arteriole is sectioned longitudinally, the elongated (cigar-shaped) nucleus of each muscle cell is cut in cross-section and thus appears small and round.

VENELE • 3 layers tunica intima, tunica media, & tunica adventitia are present in the vein but they are much thinner

The tunica media and the tunica adventita are not clearly defined. Each layer contains smooth muscle and collagen

Valves in veins prevent blood from "backing up" in the low-pressure vessels.

CAPILARELE

Capillaries in the Uterine Tube Capillary in cross section with a red blood cell. The lining of the vessels is only one cell thick

Capillaries in Skeletal Muscle Capillaries are small thin walled vessels. The "discs" in the lumen are blood cells

CORDUL

Cardiac Muscle with Purkinje Fibers.

Cardiac Muscle Cardiac muscle has a single nucleus and they are connected by intercalated discs that run transverse to the muscle cell. The connective tissue divides the cell fibers.

Cardiac muscle fibers The dark lines are intercalated discs.

Cardiac Muscle Transverse section the intercalated discs are not visible.

Cardiac Muscle Cardiac muscle cells are connected by intercalated discs that run transverse to the cell

Capillaries in the heart muscle Cardiac tissue in both transverse and longitudinal sections

This image illustrates a longitudinal-section of cardiac muscle, stained to highlight intercalated disks. Muscle striations should be visible at this magnification, but in this digital image they are obscured by pixellation. Click on thumbnail for a specimen stained with H&E.

Cardiac Muscle Cardiac muscle cells are connected by intercalated discs that run transverse to the cell

This image illustrates a longitudinal-section of cardiac muscle, clearly demonstrating the branching nature of cardiac muscle fibers. Intercalated disks.are unstained (pale). Muscle striations should be visible at this magnification, but in this digital image they are obscured by pixellation

As seen here, Purkinje fibers (cardiac muscle fibers specialized for electrical conduction) are somewhat larger and have paler cytoplasm (with relatively fewer myofibrils) than ordinary cardiac muscle.

Cardiac Muscle Layers of the cardiac muscle are epicardium (outer) myocardium (middle) & endocardium (inner)

Cardiac Muscle Purkinje fibers that are stained lighter and darker stained cardiac muscle of the myocardium.