Blood Vessels and Circulation PDF

◦ Pulmonary Vessels  Transport blood from the right ventricle of the heart through the lungs & back to the left atrium. ◦ Systemic Vessels  Transport blood from the left ventricle of the heart through all parts of the body and back to the right atrium.  Blood flow is ensured by t...

◦ Pulmonary Vessels  Transport blood from the right ventricle of the heart through the lungs & back to the left atrium. ◦ Systemic Vessels  Transport blood from the left ventricle of the heart through all parts of the body and back to the right atrium.  Blood flow is ensured by the heart’s pumping action.  Carries blood  Exchange of nutrients, wastes products & gases with tissues  Blood pressure regulation  Directs blood flow to the tissues ◦ Types of Blood Vessel  Arteries  Veins  Capillaries  carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation  Elastic arteries  Muscular arteries  arterioles TYPES OF ARTERIES Pulmonary Circulation The pulmonary circulation is the portion of the circulatory system which carries deoxygenated blood away from the right ventricle, to the lungs, and returns oxygenated blood to the left atrium and ventricle of the heart. Blood Vessels of the Systemic Circulation: Arteries Systemic circulation: 1. carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. 2. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart. BRANCHES OF THE AORTA The arch of the aorta has three branches: ▪ the brachiocephalic artery (which divides into ▪ right common carotid artery and the ▪ right subclavian artery), the left common carotid artery, and the left subclavian artery. THORACIC and ABDOMINAL OARTA MAJOR arteries of the human body. ▪ The aorta. ▪ arteries of the head and neck. ▪ common carotid artery. ▪ external carotid artery. ▪ arteries of the upper extremity. ▪ The subclavian artery ▪ The axillary artery ▪ The arteries of the trunk. ▪ The descending aorta. ▪ The arteries of the lower extremity. The femoral artery. ARTERIES OF THE UPPER LIMBS Thoracic Aorta and Its Branches Branches from the thoracic aorta include bronchial arteries, mediastinal arteries, esophageal arteries, pericardial arteries, superior phrenic artery. The thoracic aorta and the esophagus run parallel for most of its length, with the esophagus lying on the right side of the aorta. MAJOR ARTERIES OF THE PELVIS Two branches: ▪ the inferior epigastric ▪ deep circumflex iliac arteries. ▪ The internal iliac artery enters the pelvis to supply blood to pelvic organs, gluteal muscles, and the perineum. Arteries of the Lower Limbs The main artery of the lower limb is the femoral artery. It is a continuation of the external iliac artery (terminal branch of the abdominal aorta). The external iliac becomes the femoral artery when it crosses under the inguinal ligament and enters the femoral triangle. Major Systemic Veins Major Systemic Veins The capillaries, where the gaseous exchange occurs, merge into venules and these converge to form larger & larger veins until the blood reaches either the superior vena cava or inferior vena cava, which drain into the right atrium. VEINS OF THE HEAD and NECK Blood from the brain and neck flows from: (1) within the cranium via the internal jugular veins, a continuation of the sigmoid sinuses. right and left external jugular veins drain from the parotid glands, facial muscles, scalp into the subclavian veins. VEINS OF THE UPPER LIMBS There are two prominent superficial veins of the upper limb; ✓ Cephalic ✓ basilic veins, and these two extensive veins originate from the venous networks of the dorsum of the hand. The hand is drained by superficial and deep veins. THORACIC and ABDOMINAL VEINS The veins of the thorax are: the pulmonary, which carry the blood from the lungs to the left side of the heart; and the superior vena cava and its tributaries, which return the venous blood from the head and neck, the upper extremities, and the walls of the thorax, to the right side of the heart. VENOUS HEPATIC PORTAL SYSTEM The superior mesenteric vein and the splenic vein come together to form the actual hepatic portal vein. The inferior mesenteric vein connect s on the splenic vein, but in some people, it is known to connect on the portal vein or the superior mesenteric vein. HEPATIC PORTAL CIRCULATION Veins of the Lower Limb The superficial veins of the lower limb run in the subcutaneous tissue. There are two major superficial veins – the great saphenous vein, and the small saphenous vein. The great saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the great toe. Blood pressure is the force of circulating blood against the walls of blood vessels. Most of this pressure is due to work done by the heart by pumping blood through the circulatory system. "blood pressure" usually refers to the pressure in large arteries of the systemic circulation. Pulse pressure is the difference between systolic and diastolic blood pressure. It is measured in mmHG. It represents the force that the heart generates each time it contracts. Resting blood pressure is normally approx. 120/80 mmHg, which yields a pulse pressure of approximately 40 mmHg.  Factors Affecting Pulse Pressure  STROKE VOLUME (SV) ◦ stroke volume (SV) is the volume of blood pumped from the left ventricle per beat. ◦ The term stroke volume can apply to each of the two ventricles of the heart, although it usually refers to the left ventricle.  Vascular Compliance ◦ simply the basic concept of compliance applied to a vascular segment. ◦ the vascular compliance is the relationship between the volume of blood within a vascular segment and the blood pressure which is generated by the presence of that volume. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the neck (carotid artery), wrist (radial artery), at the groin (femoral artery), behind the knee (popliteal artery), near the ankle joint (posterior tibial artery), and on foot (dorsalis pedis artery). HOMEOSTATIC CONTROL OF BLOOD FLOW BARORECEPTOR REFLEXES ✓ Chemoreceptors in the brain monitor the level of carbon dioxide in the blood, as well as the pH level, or acid content. ✓ Increased carbon dioxide or decreased pH level causes the chemoreceptors to signal the heart to beat faster.  BAROREFLEX MECHANISM  The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure automatically causes the heart rate to decrease and also causes blood pressure to decrease. Decreased blood pressure decreases baroreflex activati on and causes heart rate to increase and to restore blood pressure levels. RENIN-ANGIOTENSIN-ALDOSTERONE MECHANISM RENIN-ANGIOTENSIN-ALDOSTERONE MECHANISM  The renin-angiotensin-aldosterone system (RAAS) is a signaling pathway responsible for regulating the body's blood pressure. Stimulated by low blood pressure or certain nerve impulses (e.g. in stressful situations), the kidneys release an enzyme called renin. DISEASES OF THE CARDIOVASCULAR SYSTEM  Atherosclerosis(narrowing of the arteries)  Heart attack.  Abnormal heart rhythms, or arrhythmias.  Heart failure.  Myocardial Infarction  Stroke  Heart valve disease.  Congenital heart disease.  Heart muscle disease (cardiomyopathy) ◦ Atherosclerosis ◦ Aneurysm ◦ Heart attack ◦ Myocardial Infarction  Assignment :  Diseases and Disorders of the cardiovascular System