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Part 1 The Circulatory System Ms. Ghtaura Functions of the circulatory system – Transportation • Respiratory: • Nutritive: carry • Excretory: removes to cells (e.g. amino acids and glucose) products (e.g. urea) – Regulation • Hormones: carries from the endocrine glad to target organ tissue (e.g. insulin) • Temperature: controls by adjusting blood flow to of body – Protection • Clotting: blood loss when blood vessel is • Immunity: defends against and destroying microorganisms or foreign substances Ms. Ghtaura by Composition of Blood - Plasma Blood is a fluid used for transporting suspended cells & dissolved substances It is composed of and Plasma is composed of the following: i. ii. gases: iii. : glucose, amino acids, lipids, & vitamins iv. ions (salts): with trace amounts of Ca2+, K+, & Zn2+ v. waste: vi. hormones: secreted from cells vii. : a. : made by liver for blood clotting b. : made by liver to maintain osmotic pressure of blood by increasing solute concentration of blood c. : made by liver to transport small molecules antibodies: made by white blood cells during immune response to foreign invader Ms. Ghtaura Composition of Blood – Blood Cells Blood is a fluid used for transporting suspended cells & dissolved substances It is composed of plasma and blood cells Blood cells are produced from stem cells in within certain bones and are composed of the following: i. Red blood cells: transport & some • biconcave disc: provides large surface area for • each contains large amount of Ms. Ghtaura Composition of Blood – Blood Cells Blood is a fluid used for transporting suspended cells & dissolved substances It is composed of plasma and blood cells Blood cells are produced from stem cells in bone marrow within certain bones and are composed of the following: ii. White blood cells: defend body against disease caused by invaders, i.e. provide immunity against pathogens • larger than red blood cells • function of certain cells: a. detect antigen: protein, polysaccharide, or glycoprotein on surface of foreign invaders that • triggers immune response, i.e. any molecule not by host & stimulates production of antibodies b. produce antibody: protein that binds to specific antigen, which activates other white blood cells that destroy Ms. Ghtaura Composition of Blood – Blood Cells Blood is a fluid used for transporting suspended cells & dissolved substances. It is composed of plasma and blood cells Blood cells are produced from stem cells in bone marrow within certain bones and are composed of the following: iii. Platelets: cell fragments involved in blood with NOTE: if accidently cut your hand using knife, then platelets control bleeding, while microorganisms (e.g. bacteria) on blade trigger immune response by white blood cells Ms. Ghtaura Blood Vessels - Veins • Veins – carry blood from to • Venules – Veins branch into – carries from capillaries to Ms. Ghtaura Blood Vessels - Arteries • Arteries – carry blood from to • Arterioles – Arteries branch into – carries blood from to Ms. Ghtaura Blood Vessels - Capillaries • Capillaries – exchanges nutrients from blood with from cells – A single–cell layer thick wall and narrow diameter facilitates rapid between and Ms. Ghtaura Circuits • Pulmonary Circulation – carries blood from right ventricle to lungs & oxygenated blood from lungs to left atrium of heart, i.e. pathways between heart & lungs • Systemic Circulation – carries blood from left ventricle through body & deoxygenated blood from body to right atrium of heart, i.e. pathways between & NOTE: volume of blood entering/exiting pulmonary circulation always equal to volume of blood exiting/entering systemic circulation Ms. Ghtaura The Heart Pulmonary circulation Ms. Ghtaura Blood Vessels in the Heart Anterior vena cava A. vena cava: – i. anterior: carries blood from head & arms to – ii. posterior: carries blood from abdomen & legs to heart B. aorta: carries from heart to body C. pulmonary: blood – i. arteries: carries from heart to lungs – ii. veins: carries from lungs back to heart blood blood posterior vena cava Ms. Ghtaura Pulmonary veins Pulmonary arteries Heart Chambers A. B. • atria: collects blood from veins & pumps blood into ventricles – Left atrium – oxygenated blood from the enters the left atrium via the veins – Right Atrium – deoxygenated blood enters the right via the and vena cava ventricles: pump blood out from heart to arteries – Left ventricle – collects oxygenated blood from the left via the valve – Right Ventricle – collects deoxygenated blood from the right atrium via the atrioventricular valve septum: wall that sides right & left NOTE: heart muscles receive oxygenated blood from aorta via coronary arteries & deoxygenated blood returned via coronary veins Ms. Ghtaura Valves in the Heart A. atrioventricular valves: (bicuspid/mitral or tricuspid valve) prevent backflow of blood from into atria during contraction of • B. chordae tendineae: connective tissue that prevents atrioventricular valves from inverting during of ventricles, i.e. provides structural support for valves semi–lunar valves: (pulmonary or aortic valve) prevent backflow of blood from into during relaxation of ventricles Chordae tendineae Ms. Ghtaura Passage of blood flow deoxygenated blood oxygenated blood anterior & posterior vena cava right atrium left atrium atrioventricular valve right ventricle left ventricle semilunar valve pulmonary trunk pulmonary arteries Ms. Ghtaura Coronary arteries and veins • arteries bring oxygen and nutrients to the cells • Coronary veins the blood from the muscular tissue of the into the atrium Ms. Ghtaura Heart Beat • • • • • • • SA (sinoatrial) node is in the upper dorsal wall of the right atrium AV (atrioventricular) node is located n the base of the right atrium The SA node a heartbeat every 0.85 seconds, causing the atria (when full of blood) to contract By the time this signal reaches the AV node, the delay allows the atria to finish its and then allows the ventricles to begin their contraction via AV bundle and fibres. Atrioventricular bundle (AV bundle or bundle of HIS) and the Purkinje Fibres consist of cardiac muscle fibres that help the to contract bundle runs down the septum Purkinje fibres spread through the ventricular (tissue) Ms. Ghtaura Heart Beat • The cardiac control center is located in the via the autonomic nervous system. • The nervous system has two divisions: – – (in the brain) division - decreases rate during rest division - increases rate by during exercise or stress • When our bodies are active or under stress, the sympathetic division increases the and nodal activity via hormones such as epinephrine and norepinephrine • As a result, our heart beat is stronger and faster The heart contains nervous tissue (modified myocardial tissue) which make up the and nodes in the heart Ms. Ghtaura Heart Beat 1. diastole: ventricles relaxed – initially, relaxed, atrioventricular valves open, and valves closed – sinoatrial (SA) node in right atrium impulse, which stimulates contraction of both atria – when impulse reaches junction between atrium & ventricle, atrioventricular (AV) node stimulated 2. systole: ventricles contract – atria begin to and atrioventricular valves begin to – impulse travels through Purkinje fibres, which & semi–lunar valves open Ms. Ghtaura contraction of both Blood Pressure • Is the measure of blood against the wall of a blood vessel • Systolic pressure is the arterial pressure reached when blood is pushed out of the heart – Systole = contraction of • Diastolic pressure force exerted on artery between (occurs when the ventricles are relaxed) – Diastole = relaxation of ventricles Ms. Ghtaura Blood Pressure arterial pressure measured with a on arm • recorded with systolic pressure “ ” diastolic pressure in (millimetres of mercury) • normal blood pressure range of brachial artery is typically 90/60 to / mmHg Ms. Ghtaura Abnormal Conditions 1. hypotension: low blood pressure caused by decreasing blood volume from: – – excessive (exercise, diarrhea, or vomiting) 2. hypertension: high blood pressure caused by: – increasing blood (high salt intake) – increasing rate of flow (stress) – to blood flow (atherosclerosis) Ms. Ghtaura