Circulation & Blood Vessels Chapter 14 Pages 274 – 296

Blood Circulation Page 275 Major circulatory systems Cardiopulmonary circulation – blood to the lungs & back Systemic circulation – blood to the tissues & cells & back Specialized circulatory systems Coronary circulation –blood to the heart & back Portal circulation –blood from the organs of digestion to the liver through the portal vein Fetal circulation – occurs in the pregnant female. The fetus obtains oxygen & nutrients from the mother’s blood.

Cardiopulmonary Circulation Page 275 Cardiopulmonary Circulation Deoxygenated blood from the heart flows to the lungs, where carbon dioxide is exchanged for oxygen Oxygenated blood then returns to the heart

Page 276 Figure 14-2 Right atrium  tricuspid valve  right ventricle  pulmonary valve  pulmonary arteries  lungs  pulmonary veins  left atrium  bicuspid (mitral) valve  left ventricle  aortic valve  aorta  body  vena cava

Systemic Circulation Pages 275 – 277 Circulates nutrients, oxygen, water, & secretions Carries away waste products Helps equalize body temperature Aids in protecting the body from harmful bacteria The aorta’s 1st three branches Common coronary artery Brachiocephalic artery Subclavian arteries

Page 275 Figure 14-1 Right atrium  tricuspid valve  right ventricle  pulmonary valve  pulmonary arteries  lungs  pulmonary veins  left atrium  bicuspid (mitral) valve  left ventricle  aortic valve  aorta  body  vena cava

Coronary Circulation Page 277 Brings oxygenated blood to the heart muscle Right & left branches of the coronary artery Exchange of oxygen & waste occurs at capillary level Deoxygenated blood returns through the coronary veins to the coronary sinus (a trough in the posterior wall of the right atrium)

Portal Circulation Pages 277 – 278 A branch of the general circulation Veins from the pancreas, stomach, small intestine, colon, & 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

Page 277 Figure 14-4

Fetal Circulation Pages 278 – 279 Occurs in the unborn baby (fetus) Fetus obtains oxygen & nutrients from the mother’s blood, not through its own lungs & digestive system The fetal blood does not mix with the mother’s blood; the exchange of gases, food, & waste occurs through the placenta The most common symptom of congenital heart defect is cyanosis (a bluish discoloration to the skin & mucous membrane caused by a lack of oxygen in the blood)

Page 279 Blood Vessels Arteries – Carry oxygenated blood away from the heart to capillaries (exception – pulmonary arteries) Capillaries – Smallest blood vessels & Can only be seen through a microscope Veins – Carry deoxygenated blood away from the capillaries to the heart

Arteries Page 279 Layers of the walls Tunica adventitia (externa) = consists of fibrous connective tissue with bundles of smooth muscle cells that lend great elasticity to the arteries. Tunica media = middle arterial layer Tunica intima = inner layer Aorta leads away from the heart & branches into smaller arteries Smaller arteries branch into arterioles Arterioles give rise to the capillaries

Capillaries Pages 279 – 281 Connect the arterioles & venules Muscle & connective tissue disappear & they become a simple endothelial cell layer Selective permeability Control of blood flow by precapillary sphincters – this system allows for regulation of blood flow to so-called active tissues.

Pages 281 – 282 Veins 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 cava Superior vena cava returns blood from the upper part of the body Inferior vena cava returns blood from the lower part of the body

Venous Return Pages 282 – 283 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, can cause drowsiness

Pages 283 – 284 Blood Pressure Systolic blood pressure = pressure measured at the moment of contraction. Diastolic blood pressure = pressured measured when the ventricles relax Pulse pressure = the difference between the systolic & diastolic Normal values – 120/80 Factors that affect blood pressure Volume of blood – loss of blood loss of pressure Blood viscosity – thicker blood higher pressure Total peripheral resistance – narrow vessels higher pressure Stressors – muscles around the vessel contract higher blood pressure

Page 284 Pulse Alternating expansion & contraction of an artery as blood flows through it (It should be the same as the heart rate) Can feel pulsating beat at certain points on the body; where the artery is near the surface of the skin and over a bone (pulse points)

Pulse Points Pages 284 – 285 Brachial artery – at the crook of the elbow, along the inner border of the biceps muscle Common carotid artery – in the neck, along the front margin of the sternocleidomastoid muscle, near the lower edge of the thyroid cartilage Femoral artery – in the inguinal or groin area Dorsalis pedis artery – on the anterior surface of the foot, below the ankle joint Popliteal artery – behind the knee; (hard to feel) Radial artery – at the wrist, on the same side as the thumb (most common site for taking the pulse) Temporal artery – slightly above the outer edge of the eye Pressure points can be used to stop bleeding distal to the pulse point

Effects of Aging Page 283 SB Arteries become less elastic, dilated & elongated Systolic BP increases due to reduced elasticity Baroreceptors become rigid & less sensitive to pressure changes, causing postural hypotension Can correct many congenital heart defects Baroreceptors = sensor in the artery monitors the blood pressure

Disorders of Circulation & Blood Vessels Page 285 Disorders of Circulation & Blood Vessels Aneurysm = ballooning out of an artery, accompanied by a thinning arterial wall, caused by a weakening of the blood vessel. Arteriosclerosis = occurs when the arterial walls thicken because of a loss of elasticity as aging occurs. Atherosclerosis = occurs when deposits of fat form along the walls of the arteries. Gangrene = death of body tissue due to an insufficient blood supply caused by disease or injury.

Disorders of Circulation & Blood Vessels Pages 285 – 287 Disorders of Circulation & Blood Vessels Phlebitis (thrombophlebitis) = inflammation of the lining of a vein, accompanied by clotting of blood. Embolism = a traveling blood clot. Varicose veins = swollen veins that result from a slowing of blood flow back to the heart. Hemorrhoids = varicose veins in the walls of the lower rectum & the tissues around the anus. Cerebral hemorrhage = bleeding from blood vessels within the brain. Peripheral vascular disease = caused by blockage of the arteries, usually in the legs.

Disorders of the Blood Vessels Pages 287 – 290 Disorders of the Blood Vessels Hypertension = high blood pressure Normal – Less than 120/80 Pre-hypertension – 120–130/80–89 Stage I hypertension – 140–159/90–99 Stage II hypertension – 160 & above/100 & above White coat hypertension = only high around Dr. Hypotension = low blood pressure Transient ischemic attacks (TIAs) = temporary interruptions of blood flow to the brain. Cerebral vascular accident (CVA) = sudden interruption of the blood supply to the brain [stroke] Strokes can cause: hemiplegia = paralysis on the left or right side of the body Aphasis = loss of speech & memory Dysphasia = inability to say what one wishes. **** An acronym to help assess whether someone is having a stroke is F-A-S-T Face – ask the person to smile & see if one side of the face droops down Arms – ask the person to raise both arms; watch to see if one arm drifts down Speech – ask the person to repeat a simple sentence; check for slurred speech or if the sentence is repeated back correctly Time – if any symptoms are present, call for emergency help immediately

Hypoperfusion/Shock Pages 290 – 291 Inadequate flow of blood carrying oxygen to the organs & body systems Hypoperfused tissue will stop working properly Main causes of hypoperfusion Excessive blood or fluid loss Change in size of the arteries & veins (may be too dilated, & not enough pressure to move blood through the blood vessels. Inadequate pumping of the heart Body will attempt to compensate for shock by increasing the respiration rate, increasing heart rate, or sacrificing blood supply to organs to protect blood flow to the brain.