BME-HUMAN ANATOMY-6 CIRCULATORY SYSTEM

Circulatory system - functions Transport of blood gases (O 2 & CO 2 ) Transport of substances (useful staff to and waste products out of the tissues Bleeding control (clotting system stops bleeding from the injuried area) Heat regulation (skin vessels distribute heat through the body)

Components of circulatory system Heart – pumps the blood out Vessels – tubes, where blood flows Blood – is the fluid substance of the body, which carries out all functions of the circulatory system.

Blood (p.681, fig.18.1) It is liquid connective tissue, composed of cells & extracellular fluid, called plasma Its total amount in adults is 4 to 6 L (about 70ml/kg), which comprises only circulating amount. Hematology – is the name of scince, dealing with blood

Blood cells (p.680, fig. 18.1) Erythrocytes (red blood cells, RBCs) Trombocytes (platelets) Leukocytes (white blood cells, WBCs) Granulocytes – Neutrophils – Eosinophils – Basophils Agranulocytes – Lymphocytes – Monocytes

Blood cells - Erythrocytes Function – delivers blood gases: O 2 to tissues & removes CO 2 out of tissues Amount – about 4 mln/ml Life span – about 120 days Nots: Mature cell has no nucleus. Hemoglobin is the protein, which carry blood gases (p.685, fig.18.5).

Blood cells – Trombocytes (platelets) Function – stops bleeding, i.e. one of the blood clotting system components Amount: around /ml Life span: 3 – 5 days

Blood cells - Leukocytes Function: substantial part of immune system Amount: 5000 – 9000/ml Life span: 3 weeks

Blood plazma …composed of liquid part & proteins. Blood proteins are mainly produced by the liver (except for gamma –globulins) – Albumins – Globulins – Fibrinogen

Heart …is muscular organ, which pumps blood through the vessels …is located in chest cavity …consists of 3 layers (p.718, fig.19.3) Epicard (outer) Myocard (mid, muscular) Endocard (inner …has 4 chambers (p.721, fig.19.7) 2 atrium (left & right) 2 ventricles (left & right)

Coronary circulation & Cardiac Conductive System Coronary vessles supply heart with blood (p.724, fig.19.10) – About 65% of world population has 2 coronary vessels – About 35% of world population has 1 coronary vessel Sino-Atrial node is the source of normal heartbeating (p.727, fig.19.12)

Electrocardiogram is recording of the heart electrical currents in the heart by means of an instrument called the electrocardiograph, which amplifies heart signals and register them on moving paper (p.731, fig.19.15) (p.732, fig.19.16) ECG is used for monitoring heart rythm and detect possible coronary problems

Cardiac cycles Cardiac systolic – diastolic operations is the working principle of heart chambers (p.736, fig ). Heart sounds origin from the closing valves during cardiac cycle (p.738, fig.19.20). Heart sounds can be registered by phonocardiography.

Parameters of macrocirculation Heart rate (tachicardia, bradicardia) Stroke volume (amount of blood for a single heart contraction) Cardiac output (amount of blood, pumped out by heart in 1 min) Blood pressure (force that blood presses against the wall). Total peripherial resistance, resistance to blood flow. CO = MAP/TPR

Blood vessels & circulation Artery – are vessels, which carry blood out of the heart (contain 13% of blood). Vein – are vessels, which carry blood to the heart (contain 64% of blood). Capillary – are vessels, which carry blood from arteries to veins. Systemic circulation starts from LV & ends in RA Pulmonary circulation starts from RV & ends in LA