Biol 222 Part 3-2023.pptx

Circulatory System (4 Hours, Chapter 23) Biology (Biol-222) Circulatory System Outlines Functions of human circulatory system. Components of human circulatory system. Blood Blood vessels. Heart. Cardiovascular circuits. Heart sound. Pacemaker. Biology (Biol-222) 2 Circulatory Syste...

Circulatory System (4 Hours, Chapter 23) Biology (Biol-222) Circulatory System Outlines Functions of human circulatory system. Components of human circulatory system. Blood Blood vessels. Heart. Cardiovascular circuits. Heart sound. Pacemaker. Biology (Biol-222) 2 Circulatory System Objectives Upon completion of this part, students should be able to:  Know the functions and components of the human circulatory system.  Know the cardiovascular circuits and differentiate between them.  Define the heart sound.  Know the pacemaker. Biology (Biol-222) 3 Circulatory System Functions of the circulatory system  Distributes nutrients.  Transports and exchanges oxygen & carbon dioxide.  Removes waste materials.  Has a specific role in body defenses.  Prevents excessive bleeding.  Regulates body temperature.  Takes excess fluid from interstitial fluid to the blood. Biology (Biol-222) 4 Circulatory System Cardiovascul ar system Human circulatory system consists of: Lymphatic system  Cardiovascular system  Lymphatic system Cardiovascular system consists of:  Heart  Blood  Blood vessels Biology (Biol-222) 5 Circulatory System Blood Is a fluid connective tissue consisting of:  Plasma: • Liquid part. • Transports substances (nutrients, gases, hormones, ….).  Formed elements: 1.Red blood cells (RBCs or Erythrocytes). 2.White blood cells (WBCs or Leucocytes). 3.Platelets (Thrombocytes). All blood cells arise from stem cells in red bone marrow. Biology (Biol-222) 6 Circulatory System All blood cells arise from stem cells in red bone marrow Biology (Biol-222) 7 Circulatory System RBCs (Erythrocytes):  Mature RBCs have no nuclei.  Transport oxygen and some carbon dioxide. WBCs (Leukocytes):  Have nuclei.  Defend the body against pathogens. Platelets (Thrombocytes):  Cell fragments with no nuclei.  Have a role in blood clotting or coagulation. Biology (Biol-222) 8 Circulatory System 55% Water 90% Proteins 54% Dissolved salts (sodium, potassium, calcium) Transported substances (O2, CO2, nutrients, wastes, hormones) Biology (Biol-222) 9 Circulatory System Blood vessels   Are tubes of different diameters. Transport the blood to the heart (veins) or away from the heart (arteries). Biology (Biol-222) 10 Circulatory System Blood vessels & Arteries arterioles Heart Veins Capillaries Arteries Venules Biology (Biol-222) & Veins venules Arterioles Capillaries Circulatory System11 Wall of blood vessels 12 Circulatory System Biology (Biol-222) 12 Circulatory System Arteries & Arterioles Arterie  Havesa thick muscular wall with elastic fibers.  Carry blood away from the heart.  Carry oxygenated blood (oxygen-rich blood) to the body tissues except pulmonary arteries.  Have the highest blood pressure.  Branch into smaller arterioles that deliver blood to capillaries. Biology (Biol-222) 13 Circulatory System Capillaries  Are branches of arterioles (where the speed of blood flow drops).  Have the thinnest wall of blood vessels (single layer of squamous epithelium).  They permit the exchange of materials between blood & body cells. Biology (Biol-222) 14 Circulatory System Veins & venules Blood from capillary beds enters venules (little veins) which merge into veins. Veins  Have a thinner wall than arteries.  Carry blood back to the heart.  Veins carry deoxygenated blood (oxygen-poor blood) to the heart except pulmonary veins.  Veins have the lowest blood pressure. Biology (Biol-222) 15 16 Circulatory System  Veins often have pressure-sensitive, one-way valves that allow blood to flow toward the heart when they are open and prevent the backward flow when closed.  Skeletal muscles contraction help the movement of blood in veins in the lower regions like legs. Biology (Biol-222) 16 Circulatory System Heart  It is a cone-shaped, muscular pump organ.  It is located in the thoracic cavity between the lungs. Biology (Biol-222) 17 18 Circulatory System Heart structure Biology (Biol-222) 18 Circulatory System Heart structure Biology (Biol-222) 19 Circulatory System Layers of the heart wall The heart is surrounded by a sac called Pericardium. Three layers of the heart: 1- Epicardium (outer): Thin layer attached to the pericardium. 2- Myocardium (middle): The bulk of the heart wall consists mostly of cardiac muscles. 3- Endocardium (inner): Is the epithelial lining of the heart chambers. Biology (Biol-222) 20 Circulatory System The heart chambers The human heart is divided into right and left sides, each side is divided into two chambers, so the heart consists of four hollow chambers separated from each other by septa. Heart Chambers:  Two upper small thin-walled atria.  Right atrium  Left atrium  Two lower big thick-walled ventricles.   Right ventricle Left ventricle Biology (Biol-222) 21 Circulatory System The heart chambers Right atrium Left atrium Left ventricle Right ventricle Biology (Biol-222) 22 Circulatory System The heart valves  Human heart has four one–way valves.  They prevent a backflow of the blood. The valves are:  Two Atrioventricular Valves (AV valves).  Two Semilunar Valves. Biology (Biol-222) 23 Atrioventricual (AV) valves 24 Circulatory System  Lying between the atria and the ventricles.  Are supported by chordae tendineae. Right Av valve )tricuspid valve( These valves are:  Tricuspid valve lies on the right side of the heart.  Bicuspid (or mitral) valve lies on the left side of the heart. Left Av valve bicuspid or mitral( )valve Biology (Biol-222) 24 Circulatory System Semi lunar valves  Lying between the ventricles and their attached vessels. These valves are:  The pulmonary semilunar valve lies between the right ventricle & the pulmonary artery.  The aortic semilunar valve lies between the left ventricle & the aorta. Biology (Biol-222) Pulmonary semilunar valve Aortic semilunar valve 25 Circulatory System The heart valves Left Atrioventricular valve (bicuspid) Right Atrioventricular valve (tricuspid) Aortic samilunar valve Pulmonary semilunar valve Biol 222 Biology (Biol-222) 26 Circulatory System Cardiovascular circuits The cardiovascular system consists of two distinct circuits: pulmonary and systemic circuits (double circulation). 1. The pulmonary circuit Heart Blood Lungs 2. The systemic circuit Heart Blood Body Biology (Biol-222) 27 Circulatory System Cardiovascular circuits Pulmonary circuit (short):  The right side of the heart pumps the blood to the lungs and back to the heart.  In the lungs, blood gets O2 and gets rid of CO2. Systemic circuit (long):  The left side of the heart pumps the blood to the body tissues and back to the heart.  It delivers oxygenated blood to the body cells to supply the cells with O2 and picks up the cellular wastes (CO2). Biology (Biol-222) 28 Circulatory System  The Pulmonary and Systemic Circuits Blood Blood course course Superior vena cava In lungs Inferior vena cava (Dexygenated blood) )Oxygenated blood( Pulmonar y veins Right atrium Right ventricle Left atrium Left ventricle Pulmonar y arteries Aort a Lungs Biology (Biol-222) Rest of the body Oxygenated( )blood 29 Circulatory System Biology (Biol-222) 30 Circulatory System Blood flow through the heart  The right atrium receives deoxygenated blood or oxygen poor blood (low in O2, rich in CO2) from the head and upper region of the body via the superior vena cava and from the legs and lower region of the body via inferior vena cava (vena cavae are the largest veins).  The right atrium contracts, pressure in the right atrium increases, tricuspid valve opens, and the blood passes to the right ventricle. Biology (Biol-222) 31 Circulatory System Blood flow through the heart  The right ventricle contracts, pressure in the right ventricle increases, tricuspid valve closes, and pulmonary semilunar valve opens, deoxygenated blood is pumped in the main pulmonary artery.  The pulmonary artery divides into the right & left pulmonary arteries that carry the blood to the two lungs, gas exchange occurs in capillaries where the blood picks up O2 & gives CO2 (pulmonary circuit). Biology (Biol-222) Circulatory System32 Circulatory System Blood flow through the heart  Oxygenated blood or oxygen rich blood (rich in O2, low in CO2) returned to the left atrium from the lungs via pulmonary veins.  The left atrium contracts, pressure in the left atrium increases, the bicuspid (mitral) valve opens, and the blood passes to the left ventricle (has thick muscular wall). Biology (Biol-222) Circulatory System33 Circulatory System Blood flow through the heart  The left ventricle contracts, pressure in the left ventricle increases, bicuspid (mitral) valve closes, and aortic semilunar valve opens, oxygenated blood is pumped in the aorta (the largest artery).  Aorta branches to major body regions, where O2 is used & CO2 is produced (systemic circuit).  Deoxygenated blood from tissues returns through superior and inferior vena cavae to the right atrium of the heart. Biology (Biol-222) Circulatory System34 Circulatory System Heart sounds Are two sounds Lub & Dup, result from the :closing of heart valves  At each “lub”, the AV valves are closing as the two ventricles contract (systole). It is longer and louder.  At each “dup”, the semilunar valves are closing as the ventricles relax (diastole). Biology (Biol-222) 35 Circulatory System Cardiac Conduction System Biology (Biol-222) 36 Circulatory System There are two nodal tissues 1. Sinoatrial node (SA node, pacemaker):  In the wall of the right atrium.  It initiates and sends out a muscle exciting electrical signals about 70/min to AV node and to both atria causing them to contract at the same time. Biology (Biol-222) 37 Circulatory System 2. Atrioventricular node (AV node, electric bridge to the ventricles):  Located in the right atrium.  There is a critical pause before the AV node transmits the impulse to the atrioventricular bundle.  This pause allows the atria to complete their contraction that pumps blood into the ventricles before the impulse is transmitted to the cells of the ventricle itself. Biology (Biol-222) 38 Circulatory System 3. Atrioventricular bundle (AV-bundle):  They arise from the AV node.  Signals from AV node travel through AV bundle which branches into two bundles that spread the signals in the wall of ventricles causing them to contract at the same time.  Bundle branches descend and reach the apex of the heart where they connect with the Purkinje fibers Biology (Biol-222) 39 Circulatory System Activity Name three of the functions of the -1 .cardiovascular system Name the chambers and valves of the human -2 .heart True or false 3- Capillaries are the thinnest of the blood vessels. 4- The pulmonary circuit pumps blood into the human body. Biology (Biol-222) 40 The Human Respiratory System (6 Hours, Chapter 23) Biology (Biol-222) Outlines Respiratory System • Purpose of respiration • Main functions of the respiratory system • Human Respiratory System - Air passage - Nostrils and mouth - Pharynx and larynx - Glottis, epiglottis, vocal cords - Trachea - Bronchus, bronchioles - Alveoli - Breathing mechanisms - Exchange of gases • Respiratory membrane • Gas exchange • Selected Video Links Biology (Biol-222) 42  Purpose of respiration Respiratory System  Respiration is a physiological process by which animals obtain oxygen and get rid of waste carbon dioxide by diffusion mechanism across a moist respiratory surface.  In most animals, the circulatory and respiratory systems work together to allow gas exchange.  Gas exchange is necessary because animals make ATP mainly by aerobic respiration, which requires oxygen and produces carbon dioxide (occurs at the cellular level). Biology (Biol-222) 43 Respiratory System  But physiologically, respiration is the process that helps gases to enter and leave an animal body by crossing a moist respiratory surface, usually a thin layer of epithelium (Physiological respiration). Biology (Biol-222) 44 Main functions of the respiratory system 1. Gas exchange: It draws air into and out of the lungs to get oxygen and expel carbon dioxide. 2. Vocalization “produce sound”: such as speech. 3. Smelling as it contains olfactory membrane that functions in detecting odors. 4. Help in getting rid of excess body heat. 5. Maintains the PH balance. 6. Plays a role in homeostasis. Biology (Biol-222) 45 Respiratory System  Respiration includes: 1- Breathing (ventilation): movement of air in and out of lung (inspiration and expiration). 2- External (pulmonary) respiration: Exchange of gases between air and blood through the respiratory surface in the lung. 3- Internal respiration: exchange of gases between blood and tissue fluid (interstitial fluid). 4- Cellular respiration: cells use oxygen to produce ATP. Biology (Biol-222) 46 Respiratory System Human Respiratory System Biology (Biol-222) 47 Respiratory System Respiratory airways Expirati on Inspirati on Nostrils (nasal opening) nasal cavity, mouth (oral cavity) Pharynx (throat), larynx (voice box), trachea (windpipe), two bronchi, bronchioles alveoli Biology (Biol-222) 48 Respiratory System Human Respiratory System Biology (Biol-222) 49 Respiratory System  During the passage of air from the nasal cavity to the alveoli, it is filtered, warmed and moistened. Biology (Biol-222) 50 Respiratory System A. Nasal cavity  It opens into the pharynx.  Capillaries lwarm the air.  Mucus-producing cells also secrete mucus which clean air from dust and debris.. A B  Olfactory lining layer used to detect odors B. Pharynx (throat)  Common passage for food and air.  It is the entrance to the larynx. Biology (Biol-222) 51 Respiratory System C. Larynx (voice box)  Located at the top of the trachea and has two pairs of horizontal folds (vocal cords). C  Vocal cord: consist of skeletal muscle covered by mucussecreting epithelium.  Vibration of vocal cords produces sounds.  The gap (opening) between the vocal cords is called the glottis. Biology (Biol-222) 52 Respiratory System Glottis and vocal cords of the larynx Biology (Biol-222) 53 Respiratory System  Swallowing:  Movement of food from the mouth to the stomach through the pharynx and esophagus.  During swallowing, the flap like epiglottis flops/moves down, vocal cords constrict and the opening of the larynx (glottis) is covered with epiglottis.  When food or drink enters the larynx, reflexive cough expels it out.  If food passes through the larynx and obstructs trachea, chock occurs (the person can not cough, speak, or breath and needs help). Biology (Biol-222) 54 Respiratory System D. Trachea - (windpipe) • It extends from larynx and branches to two bronchi (left and right). • It is supported and held opened by C- shaped hyaline cartilage. E. Bronchi (2) • The two branches of the trachea. • Inside each lung, each bronchus branches into bronchial tree. The branches are called bronchioles. D E F F. Bronchioles • Are fine branches of the bronchial tree. • Each bronchiole ends in an alveolar sac Biology (Biol-222) 55 G. Alveoli • Alveoli are the functional units of the lungs. • They are lined with simple squamous epithelial cells and secretory cells which release a substance (called a surfactant) that lubricates the walls, preventing them from sticking together and collapsing. • Alveoli are the site for gas exchange. Biology (Biol-222) 56 Respiratory System • Alveoli are surrounded by pulmonary capillaries which carry blood from the circulatory system (pulmonary circuit). • Alveoli exchange gases with blood flowing through pulmonary capillaries. Blood oxygenated in these capillaries returns to the heart, which then pumps it to the body’s tissues. Biology (Biol-222) 57 Respiratory System Biology (Biol-222) 58 Respiratory System Respiratory surface/membrane Respiratory membrane must be: • Thin: gases can diffuse quickly only over very short distances. • Moist: gases cross a cell membrane quickly only if they first dissolve in a fluid and then diffuse across the lipid bilayer of plasma membranes. • Has a large surface area: to speed gas exchange. Biology (Biol-222) 59 Respiratory System Gas exchange at the respiratory membrane • The respiratory surface consists of the wall of the alveolus, the wall of the capillary, and their fused basement membranes. • Gases (O2 and Co2) diffuse across this threelayered membrane between the air inside alveoli and the blood pulmonary capillaries. • It is a passive process occurs by simple diffusion. Biology (Biol-222) 60 Respiratory System H. Lungs • Two cone-shaped organs for gas exchange. • They are soft, spongy and elastic consisting of millions of alveoli. • They are found inside the ribcage (chest, thoracic cavity) to the left and right of the heart above the diaphragm. • The left lung has two lobes, the right lung has three lobes. • A two-layer-thick pleural membrane covers each lung’s outer surface and lines the inner thoracic thoracic cavity. Biology (Biol-222) 61 Respiratory System The diaphragm • It is a broad sheet of smooth muscle partition beneath the lungs between the thoracic and abdominal cavities. • Of all smooth muscles, only the diaphragm can be controlled voluntarily. • Movements of the diaphragm and intercostal muscles (the skeletal muscles between the ribs) allow breathing. The diaphragm Biology (Biol-222) 62 Respiratory System Biology (Biol-222) 63 Respiratory System Respiratory cycle • Respiratory cycle (breathing, ventilation) consists of two phases: 1- Inspiration (Inhalation) 2- Expiration (Exhalation) Biology (Biol-222) 64 Respiratory System A. Inspiration (Inhalation) • It is a single breath of air drawn into the airway. • It is an active process even at rest as it is controlled by nerve impulse and requires muscle contraction. During inhalation: 1. The diaphragm contracts and moves down. 2. The intercostal muscles contract, the rib cage moves upward and outward. 3. The thoracic cavity expands, the lung volume increases. 4. Air is pulled into the lung. Biology (Biol-222) 65 Respiratory System B. Passive expiration • It is a single breath out. (exhalation) • It is passive process at rest as it does not require muscle contraction at rest. • It becomes active by contracting the intercostal and abdominal muscles during exercise and forced expiration. During exhalation: 1. The diaphragm relaxes and moves up. 2. The intercostal muscles relax and the ribcage moves downward and inward. 3. The lung recoils and the lung volume decreases. 4. Air is pushed out of the lung. Biology (Biol-222) 66 Respiratory System Gas exchange CO2 and O2 follow the partial pressure gradient (from higher pressure to lower) Biology (Biol-222) 67 Respiratory System Gas exchange in the lung • Normally, inhaled(alveoli) air in the lung contains more O2 and less CO2. • The blood in the pulmonary capillaries contains less O2 and more CO2. • O2 diffuses from air in the lung to blood in the pulmonary capillaries (along its partial pressure gradient). • CO2 diffuses from blood in the pulmonary capillaries to the air in the lung (along its partial pressure gradient). • After gas exchange, exhaled air contains more CO2 and less O2. Biology (Biol-222) 68 Respiratory System Gas exchange in the tissues • Cells usually use O2 and produce CO2. • Concentration (partial pressure) of O2 is higher in tissue capillaries. • CO2 diffuses from cells to the blood in tissue capillaries. • O2 diffuses from the blood in tissue capillaries to inside the cells. Biology (Biol-222) 69 Respiratory System Oxygen transport In the lung  Some oxygen can dissolve in plasma, but not enough to meet the body’s needs.  Nearly all the oxygen you inhale becomes bound to hemoglobin (Hb) in your red blood cells. O diffuses from the alveoli to the plasma of the blood in the pulmonary capillaries, then binds with hemoglobin to form oxyhemoglobin (HbO2) in the RBCs.  2 O2 + Hb HbO2 Biology (Biol-222) 70 Respiratory System Oxygen transport In the tissues:  HbO2 O2 + Hb  O2 diffuses from RBCs to the plasma of the blood in the tissue capillaries to interstitial fluid (tissue fluid), then to inside the cells. • Hemoglobin is a protein (globin) with an ironcontaining cofactor called heme associated with it. • Oxygen binds reversibly to the iron in hemoglobin hemoglobin and oxygen transport Biology (Biol-222) 71 Respiratory System • Hemoglobin tends to let go of oxygen in regions where the oxygen concentration is low, the temperature is warm, the pH is low, and the concentration of carbon dioxide is high. • Such conditions occur in contracting muscles and other metabolically active tissues. • After giving up oxygen to tissues, red blood cells return to the pulmonary capillaries where they pick up more oxygen. • On their return trip from the tissues to the lungs, red blood cells carry a bit of carbon dioxide bound to hemoglobin. Biology (Biol-222) 72 Respiratory System Carbon dioxide In the tissues: transport  CO2 diffuses from the cells to interstitial fluid (tissue fluid), to the blood in the tissue capillaries.  Three mechanisms transport CO2 to the lung: 1. Dissolved in blood plasma. 2. Bind with haemoglobin to form carbaminohaemoglobin (HbCO2)in the RBCs. CO2 + Hb HbCO2 Most of CO2 is transported in the form of .3 bicarbonate ions in the RBCs by help of enzymes, .dissolves in the plasma, and is carried to the lungs carbonic acid bicarbonate Biology (Biol-222) - + 73 Respiratory System Carbon dioxide transport In the lung: • CO2 detach from hemoglobin. HbCO2 • CO2 + Hb Bicarbonate reacts with hydrogen ions to form carbonic acid which dissociates into CO2 and water. bicarbonate HCO3- + H+ carbonic acid H2CO3 CO2 + H2O CO2 and H2O diffuse from the plasma of the blood in the pulmonary capillaries to inside the alveoli and move out with exhaled air. Biology (Biol-222) 74 Respiratory System Hemoglobin and carbon dioxide transport Biology (Biol-222) 75 Video links HUMAN REPIRATORY SYSTEM https://www.youtube.com/watch?v=h-wATTsMBBA LUNG ANATOMY https://www.youtube.com/watch?v=Aw9OJLTlClQ INPIRATION AND EXPIRATION https://www.youtube.com/watch?v=lr5dDmTASos RESPIRATION https://www.youtube.com/watch?v=GjfD55C9v38 Biology (Biol-222) 76 Respiratory System Activity 1. Name three of the functions of the respiratory system. 2. Name the mechanism by which gas exchange occurs? 3. Name three of air passageways in the human respiratory system. 4. What is the name of the protein that binds and transport oxygen in the human body? 5. Explain how air moves into the lungs during inhalation. Biology (Biol-222) 77 Respiratory System 6. The process in which cells use oxygen to produce ATP is called _____________. A. B. C. D. Aerobic respiration. Anaerobic respiration. External respiration. Internal respiration. 7.During gas exchange, molecules of gases need to cross which of the following multilayered structure? A. B. C. D. Olfactory membrane. Pleural membrane. Respiratory membrane. Basement membrane Biology (Biol-222) Biology (Biol-222) 78 Respiratory System 8. A patient was suffering from a condition that makes his airways very dry. Which of the following is expected to happen to the gas exchange in this patient? A. Stay normal. B. Becomes faster. C. Becomes easier. D. Will slow down. Biology (Biol-222) 79