Blood vessel

There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

An artery (plural arteries) is a blood vessel that takes blood away from the heart to all parts of the body (tissues, lungs, etc).

The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body.

The microcirculation is the circulation of the blood in the smallest blood vessels, the microvessels of the microvasculature present within organ tissues.

There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system.

The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body.

The cardiovascular (from Latin words meaning "heart" and "vessel") system comprises the blood, heart, and blood vessels.

There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

A capillary is a small blood vessel from 5 to 10 micrometres (µm) in diameter, and having a wall one endothelial cell thick.

The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body.

Blood is circulated around the body through blood vessels by the pumping action of the heart.

There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

Veins are blood vessels that carry blood toward the heart.

When blood vessels connect to form a region of diffuse vascular supply it is called an anastomosis.

A circulatory anastomosis is a connection (an anastomosis) between two blood vessels, such as between arteries (arterio-arterial anastomosis), between veins (veno-venous anastomosis) or between an artery and a vein (arterio-venous anastomosis).

The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body.

The circulatory system comprises the heart and blood vessels (arteries, veins and capillaries).

The middle layer tunica media is the thickest layer in arteries. It consists of circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins don't have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins.

Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels.

The outer layer is the tunica adventitia and the thickest layer in veins. It is entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries (vasa vasorum) in the larger blood vessels.

The vasa vasorum is a network of small blood vessels that supply the walls of large blood vessels, such as elastic arteries (e.g. aorta) and large veins (e.g. venae cavae).

There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

The epithelium in all birds and animals is derived from the ectoderm and endoderm with a small contribution from the mesoderm, forming the endothelium, a specialized type of epithelium that composes the vasculature.

Arterioles

An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries.

The outer layer is the tunica adventitia and the thickest layer in veins. It is entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries (vasa vasorum) in the larger blood vessels.

Nerves are bundled and often travel along with blood vessels, since the neurons of a nerve have fairly high energy requirements.

Venules

A venule is a very small blood vessel in the microcirculation that allows blood to return from the capillary beds to drain into the larger blood vessels, the veins.

The outer layer is the tunica adventitia and the thickest layer in veins. It is entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries (vasa vasorum) in the larger blood vessels.

The tunica externa (New Latin "outer coat") — also known as the tunica adventitia (New Latin "additional coat"), or adventitia for short — is the outermost tunica (layer) of a blood vessel, surrounding the tunica media.

In general, arteries and arterioles transport oxygenated blood from the lungs to the body and its organs, and veins and venules transport deoxygenated blood from the body to the lungs.

The main tissue is that which is unique for the specific organ, such as the myocardium, the main tissue of the heart, while sporadic tissues include the nerves, blood vessels, and connective tissues.

It is also increased in inflammation in response to histamine, prostaglandins and interleukins, which leads to most of the symptoms of inflammation (swelling, redness, warmth and pain).

Inflammation (from inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molecular mediators.

(The values are reversed in the pulmonary circulation.) In addition to carrying oxygen, blood also carries hormones, waste products and nutrients for cells of the body.

Both lungs have a central recession called the hilum at the root of the lung, where the blood vessels and airways pass into the lungs.

Vasodilation is a similar process mediated by antagonistically acting mediators.

Vasodilation is the widening of blood vessels.

Cancer, for example, cannot progress unless the tumor causes angiogenesis (formation of new blood vessels) to supply the malignant cells' metabolic demand.

Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis.

The inner layer, tunica intima, is the thinnest layer. It is a single layer of flat cells (simple squamous epithelium) glued by a polysaccharide intercellular matrix, surrounded by a thin layer of subendothelial connective tissue interlaced with a number of circularly arranged elastic bands called the internal elastic lamina. A thin membrane of elastic fibers in the tunica intima run parallel to the vessel.

It is also increased in inflammation in response to histamine, prostaglandins and interleukins, which leads to most of the symptoms of inflammation (swelling, redness, warmth and pain).

However, while COX-1 and COX-2 are both located in the blood vessels, stomach and the kidneys, prostaglandin levels are increased by COX-2 in scenarios of inflammation and growth.

Atherosclerosis, the formation of lipid lumps (atheromas) in the blood vessel wall, is the most common cardiovascular disease, the main cause of death in the Western world.

Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels.

The middle layer tunica media is the thickest layer in arteries. It consists of circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins don't have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins.