Anatomy and Physiology of the Circulatory System and

Anatomy and Physiology of the Circulatory System and Blood

I. Function of blood and circulatory system a. b. c. Distribute heat, food, and oxygen. Removal of waste. Regulation of H 2 O content.

II. Components of Blood a. Cellular Erythrocytes (RBCs) 2. Leukocytes (WBCs) 3. Thrombocytes (Platelets) Erythro = red Leuko = white Cyte = cell Thrombo = clot 1. b. Non-cellular 4. Plasma

Connected to our blood (vascular) system is the lymphatic system, a one-way system that returns excess fluid from tissues to the blood stream – also helps fight infections.

Blood Volume: 58% plasma, 42% blood cells (primarily RBCs) l Body volume = 5 -6 liters; 9 -12 pints (8% of body weight) Blood is sticky, thick (5 times as thick as water), salty taste, and ph=7. 4 l

III. Origin of Blood Cells A. B. As a child: all bones produce blood cells. As an adult only: humerus, femur, sternum, ribs, scapula, clavicle, vertebrae, ilia, and cranium.

IV. Erythrocytes/RBCs No nucleus l Life span = 120 days l Small disc shape l Carries O 2 l Surface is elastic so they can squeeze through capillaries. l

V. Leukocytes/WBCs Nucleus l Fights infection l Phagocytes – surround & engulf bacteria & viruses. l CBC = complete blood count l Elevated WBC count = infection l

VI. Plasma 92% H 2 O + salts (Na+, K+, Mg+, Cl-) l Proteins (fibrogenin, hormones, enzymes, vitamins…) l After a meal - ↑ nutrients in the plasma l After exercise - ↑ in wastes in the plasma l

VII. Platelets Small, no nucleus, irregular shape. l Initiate a blood clotting chain of reactions. l

VIII. Blood Clotting/Coagulation/Homeostasis Small vessels constrict l Platelets stick to surface of wound until plug is formed. l

IX. Blood Types l Discovered by Karl Land Stemer – 1900 A. Genetics 3 Genes: A, B, O AA + AO A BB + BO B AB OO O

X. Importance of Blood Typing 1. 2. 3. Blood transfusions – if wrong, tiny blood clots throughout the body. Legal-paternity cases – determine who parents can or can’t be (father) Rh factor – l l A blood protein Rh+ - 85% Rh- - 15% - important to know in pregnancy.

The Heart Structure I. l l l Hollow muscular organ; sits about 2/3 to the left of the midsagittal plane. Have a set number of cells at birth – only ↑ in size of cells. Enclosed in a pericardial sac (pericardium) – actually 2 membranes – outer parietal and inner visceral – between the two is pericardial fluid which prevents friction due to heartbeats.

l l Muscle wall = myocardium – striated, involuntary cells 4 chambers 1. 2. 3. 4. l Top = atria – receiving chambers Bottom = ventricles – pumping chambers Right side = pulminary circulation Left side = systemic circulation Right side receives deoxygenated blood and pumps to the lungs then to the left side of the heart out to the body.

II. Heart Valves l l Right Atria Tricuspid valve Right Ventricle Left Atria Semilunar valve Bicuspid valve Left Ventricle Right Ventricle Left Ventricle Semilunar valve Pulmonary Artery Aorta * Bicuspid valve is much stronger than the tricuspid because the left ventricle exerts a greater force than the right.

III. Blood Supply to the Heart Since the heart is a muscle, it also needs blood, oxygen and nutrients. l Coronary arteries supply myocardium with blood. l If coronary artery is blocked…must bypass blockage. l

IV. Heart Conducting System 1. Specialized heart muscle cells in right atrium that set the pace of the heartbeat = pacemaker or SA node

V. 1. 2. 3. Control of the Heart Hormones – thyroid, adrenal (increases heart rate) brought on by stress and fear. Nervous System – variety of receptors cause nerves to release a variety of chemicals. Chemical Influence l l Atropine – nightshade plant that increases heart rate greatly. Muscarine – poisonous mushroom - stops heart entirely.

PHOTOS Nightshade Plant containing atropine Poisonous Mushroom containing muscarine

VI. Factors Affecting Heart Rate 1. 2. 3. Age – pre-birth 140 -160 then declines until age 20 when it is constant at 7075/min. Sex – women slightly higher than men. Physical Conditioning – athletes lower.

VII. Heart Sounds A. Lub – sound of ventricles contracting l B. Best heard at approximately over the 5 -6 th rib of left sternum. Dub – sound of closing semilunar valves. l l Sound is shorter in duration & higher pitch. Best heard between 2 nd and 3 rd ribs near the sternum.

VIII. Heart Disorders 1. 2. 3. 4. 5. Ischemia – lack of blood to part of the heart. Fibrillation – heart irregularities. Tachycardia – rapid heart beat. Heart murmur – from faulty valves Atrial or ventricular holes l l mix O 2 & CO 2 blood. Victim turns blue.