Arteries, Veins Arteries, Veins and Lymphaticsand Lymphatics

Presented by:Dr. Shady A. M. Negm

Bachelor's Degree School of Dentistry, Pharos University.

ArteriesArteries

• ArteriesArteries are are blood vessels that that carry blood carry blood away away from the from the heart. This . This blood is normally blood is normally oxygenated, oxygenated, exceptions made for exceptions made for the the pulmonary and and umbilical arteries

DescriptionDescription

• Arterial pressure varies between the peak Arterial pressure varies between the peak pressure during heart contraction, called the pressure during heart contraction, called the systolic pressure, and the minimum, or pressure, and the minimum, or diastolic pressure between contractions, pressure between contractions, when the heart expands and refills.when the heart expands and refills.

• Arteries carry blood away from the heart. Arteries carry blood away from the heart. Except for the Except for the pulmonary arteries, which , which carry blood to the lungs for oxygenation, all carry blood to the lungs for oxygenation, all arteries carry oxygenated blood away from arteries carry oxygenated blood away from the heart to the tissues that require oxygen. the heart to the tissues that require oxygen.

Anatomy ( Gross anatomy )Anatomy ( Gross anatomy )

• The arterial system of the The arterial system of the human body is is divided into divided into systemic arteries, carrying , carrying blood from the heart to the whole body, blood from the heart to the whole body, and and pulmonary arteries, carrying blood , carrying blood from the from the heart to the to the lungs..

Systemic arteriesSystemic arteries

• Systemic arteries are Systemic arteries are the arteries of the the arteries of the systemic circulation, , which is the part of the which is the part of the cardiovascular system which carries which carries oxygenated blood away from the heart, to away from the heart, to the the body, and returns , and returns deoxygenated blood deoxygenated blood back to the heart.back to the heart.

Pulmonary arteriesPulmonary arteries

• Pulmonary arteries are Pulmonary arteries are the arteries of the the arteries of the pulmonary circulation, , which is the portion of which is the portion of the the cardiovascular system which carries which carries deoxygenated deoxygenated blood away from the heart, to away from the heart, to the the lungs, and returns , and returns oxygenated blood back oxygenated blood back to the heart.to the heart.

Anatomy (microscopic Anatomy (microscopic anatomy )anatomy )

The outermost layer is known as the The outermost layer is known as the tunica externa formerly composed of formerly composed of connective tissue. Inside this layer is the . Inside this layer is the tunica media, or , or mediamedia, which is made up of , which is made up of smooth muscle cells and elastic tissue. The cells and elastic tissue. The innermost layer, which is in direct contact innermost layer, which is in direct contact with the flow of blood is the with the flow of blood is the tunica intima, , commonly called the commonly called the intimaintima. This layer is . This layer is made up of mainly made up of mainly endothelial cells. The . The hollow internal cavity in which the blood hollow internal cavity in which the blood flows is called the flows is called the lumen

Types of arteriesTypes of arteries

The AortaThe Aorta The The aorta is the root is the root systemic

artery. It receives blood directly artery. It receives blood directly from the left from the left ventricle of the of the heart via the heart via the aortic valve. As the . As the aorta branches, and these aorta branches, and these arteries branch in turn, they arteries branch in turn, they become successively smaller in become successively smaller in diameter, down to the diameter, down to the arteriole. . The The arterioles supply supply capillaries which in turn empty into which in turn empty into venules. . The very first branches off of the The very first branches off of the aorta are the aorta are the coronary arteries, , which supply blood to the heart which supply blood to the heart muscle itself. These are followed muscle itself. These are followed by the branches off the aortic by the branches off the aortic arch, namely the arch, namely the brachiocephalic artery, the , the left common carotid and the and the left subclavian arteries. arteries.

ArteriolesArterioles

• Arterioles, the , the smallest of the true smallest of the true arteries, help regulate arteries, help regulate blood pressure by the by the variable contraction of variable contraction of the smooth muscle of the smooth muscle of their walls, and deliver their walls, and deliver blood to the blood to the capillaries. capillaries.

CapillariesCapillaries

• The The capillaries are are where all of the where all of the important exchanges important exchanges happen in the happen in the circulatory system. The . The capillaries are a single capillaries are a single cell in diameter to aid cell in diameter to aid fast and easy diffusion fast and easy diffusion of gases, sugars and of gases, sugars and other nutrients to other nutrients to surrounding tissues. surrounding tissues.

PathologyPathology

Blood pressureBlood pressure

• Systemic arterial pressures, are generated by arterial pressures, are generated by the forceful contractions of the heart's the forceful contractions of the heart's left ventricle..

• Healthy resting arterial pressures, are relatively Healthy resting arterial pressures, are relatively low, mean systemic pressures typically being low, mean systemic pressures typically being under 100 mmHg, about 1.8under 100 mmHg, about 1.8  lbf/inlbf/in²², above , above surrounding surrounding atmospheric pressure (about 760 (about 760 mmHg).mmHg).

• Over time, elevated arterial Over time, elevated arterial blood sugar, , lipoprotein cholesterol, and , and pressure, , smoking, , and other factors are all involved in damaging and other factors are all involved in damaging both the both the endothelium and walls of the arteries, and walls of the arteries, resulting in resulting in atherosclerosis..

AtheromaAtheroma

• An An atheroma or or plaque in the artery plaque in the artery wall is a build up of wall is a build up of cell debris, that cell debris, that contain lipids contain lipids (cholesterol and fatty (cholesterol and fatty acids), calcium and a acids), calcium and a variable amount of variable amount of fibrous connective fibrous connective tissue tissue

VeinsVeins

VeinVein

• veinsveins (from the (from the Latin venavena) are ) are blood vessels that carry that carry blood towards the towards the heart. Most . Most veins carry deoxygenated blood from the veins carry deoxygenated blood from the tissues back to the heart; exceptions are the tissues back to the heart; exceptions are the pulmonary and and umbilical veins, both of which , both of which carry oxygenated blood to the heart. Veins carry oxygenated blood to the heart. Veins differ from differ from arteries in structure and function; in structure and function; for example, arteries are more muscular than for example, arteries are more muscular than veins, veins contain valves, and they carry veins, veins contain valves, and they carry blood away from the heart. blood away from the heart.

AnatomyAnatomy • In general, veins function to return In general, veins function to return

deoxygenated blood to the deoxygenated blood to the heart, and are , and are essentially tubes that collapse when their essentially tubes that collapse when their lumens are not filled with blood. The thick are not filled with blood. The thick outermost layer of a vein is made of outermost layer of a vein is made of connective tissue, called tunica adventitia or , called tunica adventitia or tunica externa. Deeper are bands of tunica externa. Deeper are bands of smooth muscle called tunica media, which called tunica media, which are, in general, thin, as veins do not function are, in general, thin, as veins do not function primarily in a contractile manner. The primarily in a contractile manner. The interior is lined with interior is lined with endothelial cells called called tunica intima. Most veins have one-way flaps tunica intima. Most veins have one-way flaps called venous valves that prevent blood called venous valves that prevent blood from flowing back and pooling in the lower from flowing back and pooling in the lower extremities due to the effects of extremities due to the effects of gravity. .

Notable veins and vein Notable veins and vein systemssystems

• The The pulmonary veins carry relatively carry relatively oxygenated blood from the lungs to the heart. oxygenated blood from the lungs to the heart. The The superior and and inferior venae cavae carry carry relatively deoxygenated blood from the upper relatively deoxygenated blood from the upper and lower systemic circulations, respectively.and lower systemic circulations, respectively.

• A A portal venous system is a series of veins or is a series of veins or venules that directly connect two venules that directly connect two capillary beds. Examples of such systems . Examples of such systems include the include the hepatic portal vein and and hypophyseal portal system

• The The Thebesian veins within the myocardium of within the myocardium of the heart are valveless veins that drain directly the heart are valveless veins that drain directly into the chambers of the heart. The coronary into the chambers of the heart. The coronary veins all empty into the veins all empty into the coronary sinus which which empties into the right atrium.empties into the right atrium.

ClassificationClassification

• Veins are classified in a number of ways, Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. including superficial vs. deep, pulmonary vs. systemic, and large vs. small. systemic, and large vs. small.

• Superficial veinsSuperficial veins– Superficial veins are those whose course are those whose course

is close to the surface of the body, and is close to the surface of the body, and have no corresponding arteries.have no corresponding arteries.

• Deep veinsDeep veins– Deep veins are deeper in the body and are deeper in the body and

have corresponding arteries.have corresponding arteries.

• Pulmonary veinsPulmonary veins– The The pulmonary veins are a set of veins are a set of veins

that deliver oxygenated blood from the that deliver oxygenated blood from the lungs to the heart. to the heart.

• Systemic veinsSystemic veins– Systemic veins drain the tissues of the drain the tissues of the

body and deliver deoxygenated blood to body and deliver deoxygenated blood to the heart.the heart.

Clinical Clinical significancesignificance

PhlebologyPhlebology

• Phlebology is the medical discipline that Phlebology is the medical discipline that involves the diagnosis and treatment of involves the diagnosis and treatment of disorders of venous origin. Diagnostic disorders of venous origin. Diagnostic techniques used include the history and techniques used include the history and physical examination, venous imaging physical examination, venous imaging techniques and laboratory evaluation techniques and laboratory evaluation related to venous related to venous thromboembolism. The . The American Medical Association has added American Medical Association has added phlebology to their list of self-designated phlebology to their list of self-designated practice specialties. A medical specialist in practice specialties. A medical specialist in Phlebology is termed a Phlebology is termed a Phlebologist. A . A related image is called a related image is called a phlebography

Venous diseasesVenous diseases

• Deep vein thrombosis :Deep vein thrombosis :

Deep-vein thrombosis is a Deep-vein thrombosis is a condition in which a condition in which a blood clot forms in a deep forms in a deep vein, which can lead to vein, which can lead to pulmonary embolism and and chronic venous chronic venous insufficiency. insufficiency.

• Thrombophlebitis :Thrombophlebitis :

Thrombophlebitis is an Thrombophlebitis is an inflammatory condition of inflammatory condition of the veins related to the veins related to blood clots. .

Lymph vesselLymph vessel

• lymph vesselslymph vessels are thin walled, are thin walled, valved structures that carry structures that carry lymph. As part of the . As part of the lymphatic system, lymph vessels are , lymph vessels are complementary to the complementary to the cardiovascular system. . Lymph vessels are lined by Lymph vessels are lined by endothelial cells, , and deep to that have a thin layer of and deep to that have a thin layer of smooth muscles, and , and adventitia that bind the that bind the lymph vessel to the surroundings. Lymph lymph vessel to the surroundings. Lymph vessels are devoted to propulsion of the lymph vessels are devoted to propulsion of the lymph from the from the lymph capillaries, which are mainly , which are mainly concerned with absorption of concerned with absorption of interstitial fluid from the tissues. Lymph vessel that carries from the tissues. Lymph vessel that carries lymph to a lymph to a lymph node are called the are called the afferent lymph vessel, and one that carries it , and one that carries it from a lymph node is called the from a lymph node is called the efferent lymph vessel, from where the lymph , from where the lymph may travel to another lymph node or may be may travel to another lymph node or may be returned to a vein, or may travel to a larger returned to a vein, or may travel to a larger lymph duct. Lymph ducts drain the lymph into . Lymph ducts drain the lymph into one of the one of the subclavian veins and thus return it to and thus return it to general general circulation. .

FunctionFunction

• Lymph vessels act as a reservoir from Lymph vessels act as a reservoir from plasma and other substances including plasma and other substances including cells that leaked from the vascular system cells that leaked from the vascular system and transport lymph fluid back from the and transport lymph fluid back from the tissues to the circulatory system. Without tissues to the circulatory system. Without functioning lymph vessels, lymph cannot functioning lymph vessels, lymph cannot be effectively drained and be effectively drained and edema typically typically results. results.

General structure of General structure of LymphaticsLymphatics

• There is an inner lining of single flattened There is an inner lining of single flattened cells composed of a type of cells composed of a type of epithelium that that is called is called endothelium, and the cells are , and the cells are called called endothelial cellsendothelial cells. This layer . This layer functions to mechanically transport fluid functions to mechanically transport fluid and since the and since the basement membrane on on which it rests is discontinuous; it leaks which it rests is discontinuous; it leaks easily.The next layer is that of easily.The next layer is that of smooth muscles that are arranged in a that are arranged in a circular fashion around the endothelium, circular fashion around the endothelium, which by shortening (contracting) or which by shortening (contracting) or relaxing alter the diameter (caliber) of the relaxing alter the diameter (caliber) of the lumen. The outermost layer is the . The outermost layer is the adventitia that consists of fibrous tissue. that consists of fibrous tissue.

• The general structure described here is The general structure described here is seen only in larger lymphatics; smaller seen only in larger lymphatics; smaller lymphatics have fewer layers. The smallest lymphatics have fewer layers. The smallest vessels (vessels (lymphaticlymphatic or or lymph capillaries) lack ) lack both the muscular layer and the outer both the muscular layer and the outer adventitia. As they proceed forward and in adventitia. As they proceed forward and in their course are joined by other capillaries, their course are joined by other capillaries, they grow larger and first take on an they grow larger and first take on an adventitia, and then smooth muscles. adventitia, and then smooth muscles.

Lymph vesselsLymph vessels

• The lymph capillaries drain the lymph to The lymph capillaries drain the lymph to larger larger contractilecontractile lymphatics, which have lymphatics, which have valves as well as smooth muscle walls. valves as well as smooth muscle walls. These are called the These are called the collecting collecting lymphatics.As the collecting lymph vessel .As the collecting lymph vessel accumulates lymph from more and more accumulates lymph from more and more lymph capillaries in its course, it becomes lymph capillaries in its course, it becomes larger and is called the larger and is called the afferent lymph vessel as it enters a lymph as it enters a lymph node. Here the lymph percolates through node. Here the lymph percolates through the lymph node tissue and is removed by the lymph node tissue and is removed by the the efferent lymph vessel. .

• An efferent lymph vessel may directly An efferent lymph vessel may directly drain into one of the (drain into one of the (right or or thoracic) ) lymph ducts, or may empty into another lymph ducts, or may empty into another lymph node as its afferent lymph vessel. lymph node as its afferent lymph vessel. Both the lymph ducts return the lymph to Both the lymph ducts return the lymph to the blood stream by emptying into the the blood stream by emptying into the subclavian veins

Head & NeckHead & Neck

Circulatory systemCirculatory system

• Blood circulates from the upper circulates from the upper systemic loop originating at the originating at the aortic arch, and includes: the , and includes: the brachiocephalic artery, , left left common carotid and left and left subclavian artery. The head and neck are . The head and neck are emptied of blood by the emptied of blood by the subclavian vein and and jugular vein. .

Blood supplyBlood supply

• The The brachiocephalic arterybrachiocephalic artery or trunk is the or trunk is the first and largest first and largest artery that branches to form that branches to form the the right common carotid artery and the artery and the right subclavian artery. This artery provides . This artery provides blood to the right upper chest, right arm, blood to the right upper chest, right arm, neck, and head, through a branch called right neck, and head, through a branch called right vertebral artery. The right and left vertebral . The right and left vertebral artery feed into the artery feed into the basilar artery and upward and upward to the to the Posterior cerebral artery, which , which provides most of the brain with oxygenated provides most of the brain with oxygenated blood. The blood. The posterior cerebral artery and the and the posterior communicating artery are within the are within the circle of Williscircle of Willis. .

• The The left common carotid arteryleft common carotid artery divides divides to form the: to form the: internal carotid artery (ICA) (ICA) and an and an external carotid artery (ECA). The (ECA). The ICA supplies the brain. The ECA supplies ICA supplies the brain. The ECA supplies the neck and face. the neck and face.

• The The left subclavian arteryleft subclavian artery and the and the right right subclavian arterysubclavian artery, one on each side of , one on each side of the body form the the body form the internal thoracic artery, , the vertebral artery, the the vertebral artery, the thyrocervical trunk, and the , and the costocervical trunk. The . The subclavian becomes the axiliary artery at subclavian becomes the axiliary artery at the lateral border of the first rib. The the lateral border of the first rib. The left left subclavian arterysubclavian artery also provides blood to also provides blood to the left upper chest and left arm. the left upper chest and left arm.

Blood-brain Blood-brain barrierbarrier

• The The Blood-brain barrier (BBB) is semi- (BBB) is semi-permeable membrane that controls the permeable membrane that controls the capillary leak potential of the circulatory capillary leak potential of the circulatory system. In most parts of the body, the system. In most parts of the body, the smallest blood vessels, called smallest blood vessels, called capillaries, are , are lined with endothelial cells. lined with endothelial cells. Endothelial tissue tissue has small spaces between each individual cell has small spaces between each individual cell so substances can move readily between the so substances can move readily between the inside and the outside of the vessel. However, inside and the outside of the vessel. However, in the brain, the endothelial cells fit tightly in the brain, the endothelial cells fit tightly together to create a together to create a tight junction and and substances cannot pass out of the substances cannot pass out of the bloodstream. Some molecules, such as bloodstream. Some molecules, such as glucose, are transported out of the blood by , are transported out of the blood by active transport. .

Blood returnBlood return

• Blood from the brain and neck flows within Blood from the brain and neck flows within the the cranium via the via the internal jugular veins, , a continuation of the a continuation of the sigmoid sinuses. The . The right and left right and left external jugular veins drain drain from the from the parotid glands, facial muscles, , facial muscles, scalp into the subclavian veins. The right scalp into the subclavian veins. The right and left vertebral veins drain the vertebrae and left vertebral veins drain the vertebrae and muscles into the right subclavian vein and muscles into the right subclavian vein and into the and into the superior vena cava, into the , into the right atrium of the of the heart. .

Lymphatic systemLymphatic system

• The lymphatic system drains the head and The lymphatic system drains the head and neck of excess neck of excess interstitial fluid via via lymph vessels or capillaries, equally into the or capillaries, equally into the right lymphatic duct and the and the thoracic duct..

• Lymph nodes line the cervical spine and neck Lymph nodes line the cervical spine and neck regions as well as along the face and jaw.regions as well as along the face and jaw.

• The The tonsils also are lymphatic tissue and help also are lymphatic tissue and help mediate the ingestion of pathogens.mediate the ingestion of pathogens.

• Tonsils in humans include, from superior to Tonsils in humans include, from superior to inferior: inferior: nasopharyngeal tonsils (also known (also known as as adenoids), ), palatine tonsils, and , and lingual tonsils..

• Together this set of lymphatic tissue is called Together this set of lymphatic tissue is called the tonsillar ring or the tonsillar ring or Waldeyer's ring..

Nervous systemNervous system

• The The nervous systemnervous system is composed of a is composed of a central nervous system (CNS), (CNS), brain and and spinal cord, and the , and the peripheral nervous system (PNS), (PNS), cranial nerves and and spinal nerves. The . The CNS is located within the CNS is located within the dorsal cavity, and the , and the PNS extends through the . The central nervous PNS extends through the . The central nervous system provides control and coordination of all system provides control and coordination of all eleveneleven body systems and utilizes the body systems and utilizes the endocrine system to form to form hormone chemical chemical messengers that transport through the blood to messengers that transport through the blood to influence the activity of individual cells of the influence the activity of individual cells of the body and their associated tissues, organs and body and their associated tissues, organs and systems. systems.

• The CNS receives sensory (The CNS receives sensory (afferent) input ) input from the PNS and directs the flow of from the PNS and directs the flow of information to information to association neurons ( (interneurons), located in the ), located in the grey matter of of the spinal cord and brain to create the spinal cord and brain to create chemical synapse responses which in turn responses which in turn cause the formation of motor (cause the formation of motor (efferent nerve) ) responses to responses to stimulus. .

• The CNS is protected by the The CNS is protected by the cranium, , vertebral column, meninges, cerebrospinal vertebral column, meninges, cerebrospinal fluid. The spinal cord, which is an extension of fluid. The spinal cord, which is an extension of the brain, and brain stem are joined at the the brain, and brain stem are joined at the base of the cranium at the foramen magnum. base of the cranium at the foramen magnum.

• The PNS has two subdivisions :The PNS has two subdivisions :

A)somatic nervous system (SNS). The SNS A)somatic nervous system (SNS). The SNS is associated with the voluntary control of is associated with the voluntary control of body movements through the action of body movements through the action of skeletal muscles, and also reception of skeletal muscles, and also reception of external stimuli. external stimuli.

B) the autonomic nervous system (ANS). B) the autonomic nervous system (ANS). The ANS is divided into subsystems: the The ANS is divided into subsystems: the sympathetic nervous system (SNS) and sympathetic nervous system (SNS) and the parasympathetic (PNS) nervous the parasympathetic (PNS) nervous systems. The SNS and PNS often have systems. The SNS and PNS often have opposing effects in the same organs or opposing effects in the same organs or physiological systems, and the ANS is a physiological systems, and the ANS is a major factor in maintaining homeostasis. major factor in maintaining homeostasis.

ReferencesReferences