Cardiovascular System Chapters 11, 12
Oxygen enters the cardiovascular system by diffusing from alveoli into blood cells in the capillaries, then binding to hemoglobin in red blood cells.
Blood Hematology- the study of blood, blood forming tissues, and the disorders associated with them. Blood consists of 2 components. Plasma (55%) Water (92%). Proteins (8%). Formed Elements (45%) Erythrocytes (99%)- red blood cells. Leukocytes (<1%)- white blood cells. Platelets (<1%)- a fragment of cytoplasm enclosed in a cell membrane.
Characteristics of Blood 1 Drop of blood contains 250 million blood cells. Blood is denser than water. Blood temperature is about 100.4 F. ph= 7.35-7.45. Blood is about 8% of total body weight. Blood volume in Men is 5-6 liters (1.5 gallons). Women is 4-5 liters (1.2 gallons).
Hemoglobin 280 million molecules of hemoglobin per red blood cell. Hemoglobin- oxygen binding protein/pigment. Globin protein that consists of 4 polypeptide chains. Heme molecules are attached to each polypeptide chain. Each heme contains an iron ion (Fe+2) that binds to oxygen. Transports oxygen from the lungs to tissue cells and transports part of the carbon dioxide to the lungs.
Hematocrit and Blood Disease Hematocrit- percentage of blood occupied by cells. Female normal range 38-46% (aver.- 42%) Male normal range 40-54% (aver.- 46%) Anemia- reduced RBCs or not enough hemoglobin. Hemoglobinopathyblood disease.
Anatomy The Heart Cone-shaped, the size of a closed fist (5 inches in length, 3.5 inches in width, 2.5 inches thick). The heart has: 2 atria (upper chambers). 2 ventricles (lower chambers). 4 valves. The heart consists mostly of myocardium (cardiac muscle tissue). Function Pump blood. About 3,600 gallons pumped per day. Beats about 72 times per minute, over 100,000 times per day.
The Heart- external
The Heart- internal
Atrial Systole The Cardiac Cycle Diastole Ventricular Systole
Measuring Blood Pressure Sphygmomanometer Blood Pressure- a measure of arterial pressure in the brachial artery. Systolic pressure= pressure during contraction (120 mm Hg). Diastolic pressure= pressure during relaxation (80 mm Hg).
The valves prevent backflow of blood Pulmonary valve Aortic valve Bicuspid (mitral valve) Tricuspid valve
Normal Heart vs. Mitral Valve Prolapse
Internal Conduction System Sinoatrial node (SA, pacemaker). Atrioventricular node (AV). Atrioventricular bundle. Purkinje Fibers.
Heart Arteries Arterioles Capillaries Venules Veins Heart Heart Heart Vein Artery Venule Capillary Arteriole
Arteries vs. Veins Each have the 3 layers. The middle layer of an artery shows more smooth muscle. The lumen is smaller in arteries. Veins often contain valves. Veins are blood reservoirs, and hold 65% of blood. Artery Smooth Muscle Valve Vein
Capillaries are sites of exchange Capillaries are microscopic, narrow vessels. Substances are exchanged through the plasma membrane of the capillary. Arterial end of capillary Blood pressure forces fluid out of the capillary. Venous end of capillary Fluid is drawn back into the capillary by osmotic pressure.
Blood pressure Decreases in capillaries. Blood velocity Decreases in capillaries due to greater surface area.
Pulse- a pressure wave created by the ejection of blood from the left ventricle into the aorta.
Drainage- the flow of blood back to the heart. Accomplished by Skeletal muscle contraction. Valves in veins. Respiratory movements.
Atherosclerosis Atherosclerosis- the buildup of lipids in the artery walls. (athero- yellow; sclerosis- hardening). Buildup of fatty deposits (plaques), particularly LDLs (bad cholesterol), obstructs blood flow. Leading cause of heart attacks (death of heart muscle cells) and strokes (death of brain cells).
Balloon Angioplasty A catheter and baloon are threaded into the coronary artery to the point of blockage. The balloon is inserted into the blocked area and inflated. Plaque is pushed to the artery walls.
Coronary Bypass Surgery
Lymphatic System Cardiovascular + Lymphatic = Circulatory System
Lymphatic Components Lymphatic vessels and ducts. Lymph- fluid. Lymphatic Organs Red bone marrow Thymus Spleen Lymph nodes Diffuse lymphatic tissue Tonsils, adenoids & Peyer s patches.
Function #1- Draining excess interstitial fluid & plasma proteins from tissue spaces. About 85% of what exits the arterial end is reabsorbed by the venous end of the capillaries. The 15% that doesn t return is excess tissue fluid, it is absorbed by the lymphatic system.
Lymph is returned to the bloodstream just above the heart in the brachiocephalic veins.
Function #2- Transporting dietary lipids and vitamins from the GI tract to the blood.
Function #3- Facilitating immune responses by recognizing microbes or abnormal cells and killing them directly or by antibodies.
Basophil Eosinophil Neutrophil 1% 3% 66% Lymphocyte Monocyte 24% 6%
White Blood Cells Function- fight infection; defend against pathogens that invade the body. Granular leukocytes Neutrophils- phagocytosis and destruction of bacteria (pus). Eosinophils- destroy worms, lessen the severity of allergies. Basophils- release histamine, a chemical that attracts other white blood cells to the site of infection, causes blood vessels to dilate. Agranular leukocytes Lymphocytes T cells- attack viruses, cancer cells, and transplanted tissue cells. B cells- develop into plasma cells that secrete antibodies. Natural killer cells- attack microbes and tumor cells. Monocytes- develop into phagocytotic macrophages.
Red Bone Marrow Spongy bone- site of red and white blood cell production. Stem cells in the marrow give rise to all formed elements.
Lymph Node Anatomy Bean-shaped organ, up to 1 inch long (1-25 mm), located along lymphatic vessels. Scattered throughout body but concentrated near mammary glands, axillae, and the groin. About 600 per human.
Lymph Node Function Lymph nodes filter lymph. House macrophages that phagocytize debris, cancer cells, viruses, and bacteria. House lymphocytes that mount attacks on pathogens.
Spleen Anatomy 5 inch long organ between stomach and diaphragm. Function Destroy bacteria and viruses. The white pulp consists of mostly lymphocytes and macrophages. Filter old and damaged red blood cells and pathogens from blood. The red pulp consists of mostly lymphocytes and macrophages.
Thymus Gland Large in infants (70 g), atrophied in adult (3 g). 2 lobed organ. Each lobule has a cortex and medulla. The cortex is tightly packed with lymphocytes & macrophages. Chief Function Aid in the maturation of T- lymphocytes.
Lymphatic Nodules Lymphatic nodulesoval-shaped concentrations of lymphatic tissue. Tonsils- form a ring around the throat where they protect against disease organisms that are inhaled or swallowed. Peyer s patcheskeep bacteria from breaching the wall of the ileum. Pharyngeal tonsil (adenoid) Palatine tonsil Lingual tonsil