Circulation and Blood Vessels Chapter 14 Circulation and Blood Vessels

Objectives Trace the path of cardiopulmonary circulation Name and describe the specialized circulatory systems Trace the blood in fetal circulation List the types of blood vessels Identify the principal arteries and veins of the body Describe some disorders of the blood vessels Define the key words that relate to this chapter

Blood Circulation Major circulatory systems Cardiopulmonary circulation Systemic circulation Specialized circulatory systems Coronary circulation Portal circulation Fetal circulation

Cardiopulmonary Circulation Deoxygenated blood from the heart to the lungs where carbon dioxide is exchanged for oxygen. The oxygenated blood then returns to the heart. Review of blood flow through the heart and lungs

Systemic Circulation Circulates nutrients, oxygen, water, and secretions Carries away waste products Helps equalize body temperature Aids in protecting the body from harmful bacteria The aorta and its branches

Coronary Circulation Brings oxygenated blood to the heart muscle Right and left branches of the coronary artery Exchange of oxygen and waste occurs at capillary level Deoxygenated blood returns through the coronary veins to the coronary sinus

Portal Circulation A branch of the general circulation Veins from the pancreas, stomach, small intestine, colon and spleen empty their blood into the hepatic portal vein which goes to the liver Liver ensures that the blood’s glucose concentration is kept within a relatively narrow range

Fetal Circulation Occurs in the unborn baby (fetus) Fetus obtains oxygen and nutrients from the mother’s blood; not through their own lungs and digestive systems The fetal blood does not mix with the mother’s blood; the exchange of gases, food and waste is passed through the placenta

Blood Vessels Arteries Capillaries Veins

Arteries Carry oxygenated blood away from the heart to capillaries (exception – pulmonary arteries) Layers of the walls Tunica adventitia or externa Tunica media Tunica intima Aorta leads away from the heart and branches into smaller arteries Smaller arteries branch into arterioles Arterioles give rise to the capillaries

Capillaries Smallest blood vessels Can only be seen through a microscope Connect the arterioles and venules Muscle and connective tissue disappear and they become a simple endothelial cell layer Selective permeability Control of blood flow by precapillary sphincters

Veins Carry deoxygenated blood away from the capillaries to the heart Layers of the walls Tunica externa, Tunica media, Tunica intima Walls much thinner than arteries Do not have to withstand as much pressure Veins have valves so blood flows in one direction Toward the heart Largest vein is the vena cavae Superior vena cava returns blood from upper part of body Inferior vena cava returns blood from the lower part of the body

Venous Return Valves help keep venous blood moving Skeletal muscles contract to push venous blood along its path Pressure changes occur when we breath which helps bring venous blood back to the heart Stationary positioning can decrease flow back to the heart for oxygenation

Blood Pressure Systolic blood pressure Diastolic blood pressure Pulse pressure Normal values Systolic pressure averages 120 mm/Hg Diastolic pressure averages 80 mm/Hg Normal range 95/60 to 120/80

Pulse Can feel pulsating beat at certain points on the body Should be same as heart rate Can feel pulse on the body where the artery is near the surface of the skin and over a bone These are called pulse points

Pulse Points 7 paired pulse points Brachial artery Common carotid artery Femoral artery Dorsalis pedis artery Popliteal artery Radial artery Temporal artery Pressure points can be used to stop bleeding distal to the pulse point

Congenital Heart Defects Occur when there is a malformation of the heart during fetal development Most common symptom Cyanosis Microscopic surgery Can correct many congenital heart defects

Disorders of the Blood Vessels Aneurysm Arteriosclerosis Atherosclerosis Gangrene Phlebitis or thrombophlebitis Embolism Varicose veins Hemorrhoids Cerebral hemorrhage Peripheral vascular disease

Disorders of the Blood Vessels Hypertension Normal Less than 120/80 Pre-hypertension 120-130/80-89 Stage I hypertension 140-159/90-99 Stage II hypertension 160 and above/100 and above White coat hypertension Hypotension Transient ischemic attacks (TIAs) Cerebral vascular accident (CVA)

Hypoperfusion Inadequate flow of blood carrying oxygen to the organs and body systems Hypoperfused tissue will stop working properly Hypoperfusion leads to shock Body attempts to compensate for hypoperfusion by increasing respiratory rate, increasing the heart rate or sacrificing organs to protect blood flow to the brain