Circulation and Immunity Slides PDF (2022)

Unit D2: The Circulatory and Immune Systems  Did You Know? ➔ All the blood vessels in your body would stretch out to 100 000 km – enough to go around the Earth more than twice! ➔ A blue whale’s heart is about the size of a compact car and only beats 5 times/min. ➔ A shrew has a heart...

Unit D2: The Circulatory and Immune Systems  Did You Know? ➔ All the blood vessels in your body would stretch out to 100 000 km – enough to go around the Earth more than twice! ➔ A blue whale’s heart is about the size of a compact car and only beats 5 times/min. ➔ A shrew has a heart rate of about 1000 beats/min ➔ Blood is never blue!!! System Main Functions of the Circulatory System 1. Transport gases, nutrients, hormones, and wastes in the body. 2. Regulate internal temperature. 3. Protect against blood loss from injury and against disease-causing microbes and toxins.  Major Components of the Circulatory System 1. Heart: an organ that pushes blood through the body. 2. Blood vessels: pathways for blood to travel through. 3. Blood: carries nutrients, gases, water, wastes, and other materials throughout the body. Structure of the Heart – Let’s LABEL! Structure of the Heart Heart Structure Function - Made of specialized myogenic cardiac muscle (muscle cells Cardiac muscle called myocyte cells) - under involuntary control, rhythmic - myogenic contractions – muscle cells contract, no nerve stimulation needed - Fibrous sac Pericardium - holds heart in centre of chest Myogenic Muscle Contraction Chambers Top “receiving” Chambers: Right Atrium Left Atrium Bottom “pumping” Chambers: Right Ventricle Left Ventricle  - Muscular wall Septum - separates the left side and right side of heart Superior vena Collects oxygen-poor blood from the cava head, chest and arms. Inferior vena cava Collects oxygen-poor blood from parts of the body below the heart. Pulmonary Vessels that carry oxygen-poor blood Arteries from right ventricle to the lungs. *Only arteries that carry O2-poor blood (Arteries = Away from heart)  Carry oxygen-rich blood from lungs to left atrium Pulmonary *Only veins that carry O2-rich blood Veins - Largest blood vessel in body - O2 rich blood in left ventricle → Aorta AORTA → body - Branches into coronary arteries to carry blood to heart tissue  Tricuspid valve Separates the right atrium (Right AV valve) from the right ventricle *Three flaps* Bicuspid valve Separates the left atrium (Left AV valve or Mitral Valve) from the left ventricle *Two flaps*  Bicuspid Valve or Left AV Valve Right AV Valve  Pulmonary semilunar valve: separates Semilunar valves right ventricle from pulmonary trunk (arteries carrying O2-poor blood). Aortic semilunar valve: separates the left ventricle from the aorta.  - Strong, fibrous strings - prevent valves from inverting when Chordae heart contracts Tendinae - controlled by papillary muscles in ventricles. Structure of the Blood Vessels Blood Structure Function Vessel Description Type - 3 cell layers - Carry blood AWAY from Artery thick the heart - Elastic walls - Expansion/recoil (pulse) - Smaller of the artery keeps the opening than blood flowing and veins (b/c maintains blood pressure walls are - Arteriole = smaller thicker) branch of an artery; connects artery to capillaries  - 1 cell layer thick Networks for the Capillary - blood cells must exchange of matter travel single file (O2, CO2, nutrients, waste) between the blood and cells. Vein - 3 cell layers thick Carry blood TOWARDS the - Thinner walls than heart. arteries, so larger inner circumference Contain low pressure blood - One-way valves (1/12th the pressure of prevent back-flow arteries!) of blood - Not elastic (can’t Rely on skeletal muscles contract like and valves to keep blood arteries) flowing. Venules = branch of a vein; connect vein to capillary A. Muscles contract and B. Muscles relax, blood in vein flows squeeze vein, pushing back briefly. Slight backward flow blood past the one-way forces valve closed, this prevents valve further backflow. Structural Comparison of Arteries, Veins and Capillaries ⚫ Both arteries and veins have 3 cell layers, but arteries are thicker Outer layer connective & elastic tissue Middle layer elastic and smooth muscle tissue Inner layer flat, smooth cells (one cell thick) O2 rich blood from heart O2 poor blood back to heart Pathways of the Circulatory System ⚫ The pulmonary pathway transports blood between the right side of the heart and the lungs. ⚫ The systemic pathway transports blood between the left side of the heart and the body. ⚫ The coronary pathway provides blood to the muscle tissue of the heart itself. Tracing Blood Flow Through the Pulmonary & Systemic Pathways How a Heart Pumps Blood (1 min) https://youtu.be/JA0 Wb3gc4mE Let’s label the pathway of blood! Bloodmobile Song (2 min) https://youtu.be/Futnu_6NmQo  The Heart Beat 1. The sinoatrial (SA) node (“pacemaker”) is a bundle of specialized muscle tissue that generates an electrical signal to stimulate the atria to contract. 2. As the atria contract, the signal reaches the atrioventricular (AV) node, where it is delayed. 3. The AV node transmits the electrical signal through a bundle of specialized fibers called the bundle of His. 4. The bundle of His relays the signal through two bundle branches that divide into fast-conducting Purkinje fibers. 5. The Purkinje fibers initiate the contraction of the ventricles. Beating Heart Animation (1:30) https://youtu.be/zhqO33nWoDM  Order of Events: Heart Beat ➔ Blood enters atria → SA node stimulates atria → contract ➔ Bicuspid & tricuspid valves open → blood moves into ventricles ➔ Purkinje Fibers stimulate ventricles → contract ➔ Bicuspid & tricuspid valves close “LUB”, semilunar valves open → blood leaves ventricles → semilunar valves close “DUB” Electrocardiogram (ECG)  Blood Pressure ➔ Blood pressure is the pressure exerted on vessel walls by blood as it passes through. ➔ When the ventricles contract (“systole”) and force blood into the pulmonary arteries and aorta, the pressure in the arteries increases. ◆ The maximum pressure during ventricular contraction is called systolic pressure. ➔ The ventricles then relax (“diastole”) and the pressure in the arteries decreases. ◆ The lowest pressure before the ventricles contract again is called the diastolic pressure. ➔ BP measured using a sphygmomanometer Systolic 120 mmHg Diastolic 80 mmHg ➔ Nicotine and caffeine increase heart rate and blood pressure (due to temporary restriction of blood vessels).  Cardiac Output and Stroke Volume ➔ Cardiac output (mL/min) = amount of blood pumped by the left ventricle per minute (Average: 5000 mL/min if fit) ➔ Stroke volume (mL) = amount of blood forced out of the left ventricle with each heartbeat (Ave: 60-80mL) ➔ Heart rate (bpm) = number of times the heart beats per minute (Ave: 60-100 bpm) ➔ Cardiac output (mL/min) = heart rate x stroke volume Ave: ≈ 5L/min if fit  Cardiovascular Fitness ➔ A low resting heart rate indicates cardiovascular fitness because it means that stroke volume is high ➔ Regular cardiovascular exercise will ◆ enlarge the ventricular chambers ◆ increase the distensibility of the ventricles Miguel Indurain – 28 bpm!! ◆ strengthen the ventricle walls. Blood Pressure and Velocity in the Vessels 8.2 Blood and Circulation FLUID portion = plasma Formed (SOLID) portion = RBC, WBC, platelets (all produced in bone marrow) 1. Red Blood Cells (Erythrocytes) ➔ Make up about 44% of the blood volume. ➔ Lifespan of about 120 days then they are broken down in the liver and excreted as bile pigments. ➔ Extra red blood cells are stored in the spleen. ➔ A mature red blood cell is enucleated (no nucleus) to allow it to hold more hemoglobin. ➔ Hemoglobin is an iron-containing protein that binds oxygen (it also carries 25% of CO2 In blood!!) Fun Fact: Each RBC contains about 250 million hemoglobin molecules and each hemoglobin can bind up to 4 O 2 mol’s! ➔ Anemia is caused by insufficient red blood cells or hemoglobin. ➔ When in a hypoxic (low O2) environment for a prolonged period of time, humans will produce more red blood cells (e.g. high altitudes, low level carbon monoxide exposure). 2. White Blood Cells (Leukocytes) ➔ Make up less than 1% of the total blood volume (but may more than double if fighting infection). ➔ Life span 5-20 days ➔ Leukocytes are the cells of the bodyʼs immune response. 3. Platelets (Thrombocytes) ➔ Platelets are fragments of cells that form when larger cells in the bone marrow break apart. ➔ Make up a fraction of 1% of the blood volume. ➔ They have no nucleus and they live for about 2-8 days. ➔ Function: aid in blood clotting.  Functions of Blood 1. Transport of… ➔ hormones (signaling molecules) throughout the body. ➔ nutrients, vitamins, and minerals from digested food. ➔ gases between the respiratory system and body tissues. ➔ Wastes from cells are transported through the blood to be excreted from the body. 2. Blood Clotting ➔ When injury to a blood vessel occurs, substances released by the broken blood vessel attract platelets to the site. FIBRIN = insoluble strands that form a mesh around injured area; mesh traps blood cells. This is a blood clot! 3. Homeostatic Regulation ➔ When the bodyʼs internal environment becomes too warm the nervous system stimulates the blood vessels close to the skin to dilate – called vasodilation. Heat can be transferred from blood to skin to air ➔ Note: The body also cools itself by sweating. FYI! Dehydration can be a problem if trying to get rid of excess heat via sweating when you have a fever – this is why fluid intake important! ➔ When the external environment is too cold, blood vessels near the surface of the skin constrict – vasoconstriction. This will reduce heat loss from blood and across skin ➔ The body also generates heat by shivering. ➔ Vasodilation and vasoconstriction may be controlled by the brain in response to changes in blood pressure also used regulate blood pressure. ◆ If BP too high, vasodilation creates larger opening, more blood flow - blood pressure will decrease. ◆ If BP too low, vasoconstriction will create smaller opening, harder to push blood - causes blood pressure to increase. ➔ Exercising – increases vasodilation in the muscles, heart, and lungs so tissues can access more oxygen!  Circulation and the Action of Capillaries ➔ The capillaries are the site of exchange between the blood and the cells of the body tissues. ➔ Wastes and CO2 leave the cells of the body and enter the bloodstream. ➔ Nutrients (e.g. glucose, amino acids), oxygen and water leave the bloodstream and enter the cells of the body. ➔ Blood can be shunted directly from the artery to the vein, bypassing the capillaries through the action of sphincters that tighten and close the opening. ◆ This controls how much blood is flowing through various tissues of the body at any given time.  Fun Facts About Cap’s! ➔ Capillaries are the only blood vessels thin enough for diffusion of gases and other materials (recall that blood flow is slowest through capʼs – this allows time for diffusion!) ➔ Any given cell in the body is one to three cell widths away from a capillary ➔ You have about 1 billion capillaries in your body – total surface area about the same as a football field!  8.3 The Lymphatic System ➔ The lymphatic circulatory system is a network of vessels with associated glands (synthesize substances) and nodes (knot-like mass of tissue) that extends throughout the body. ➔ Thymus gland: site of T-cell maturation (type of WBC) ➔ Spleen: stores RBCʼs; also contains monocytes (precursor to macrophage) ➔ Red bone marrow: site of RBC, WBC and platelet production. ➔ The lymphatic vessels contain a fluid called lymph, which is made up of interstitial fluid (the fluid that surrounds cells). ➔ Lymph forms in closed end tubes in capillary beds (different to blood, which is in continuous circuit to and from heart). ➔ Lymph vessels have valves to ensure one way flow (just like veins!)  Main Functions of the Lymphatic System ➔ Help maintain the balance of fluids in the body. ◆ Some blood plasma escapes the capillaries and becomes part of the interstitial fluid. ◆ Lymphatic vessels absorb interstitial fluid and carry it to ducts that empty into large veins near the heart. ➔ Transport products of fat digestion from the small intestine into the bloodstream. ➔ Help defend against disease-causing organisms. ◆ T-lymphocytes and B-lymphocytes (types of WBCʼs) are found in the lymph nodes (they mature there). ◆ The lymph nodes also contain macrophages to trap and destroy bacteria circulating within the body. ◆ This is why, when your body is fighting an infection, you can sometimes feel swollen lymph nodes (e.g. back of neck)  8.4 The Defence System The Need for an Immune System ➔ Bacteria, fungi, protists, viruses, and other microbes are in the air we breathe, the food we eat, and the water we drink. Recognize this enemy?? ➔ The human body is an ideal place for microorganisms to live and reproduce. ➔ Most microorganisms in the body cause little or no damage to us, but some, called pathogens can be dangerous. ➔ The human body protects itself by preventing the entry of pathogens and destroying pathogens that do enter.  The First Line of Defence – Non-Specific ➔ All of the initial physical and chemical barriers of the body: ◆ Eyelashes (physical) – prevent pathogens from entering the eye. ◆ Cilia of the respiratory tract (physical) – actively moves debris out of the respiratory tract. ◆ Tears (chemical and physical) – wash away foreign particles; contain the enzyme lysozyme ◆ Stomach acid (HCl) (chemical) – low pH kills microorganisms. ◆ Mucus (physical) – traps foreign particles throughout the respiratory tract. ◆ Nose hairs (physical) – trap foreign particles, preventing them from entering the respiratory tract.  ◆ Skin (physical and chemical) perspiration (sweat) is acidic and skin oils contain bactericides that kill many bacteria skin cells contain a tough, indigestible protein called keratin. Keratin adheres skin cells to each other and forms protective layer on outside of skin – prevents pathogens from slipping between cells ◆ Vomiting and diarrhea (physical) – clear pathogens out of the digestive tract. ➔ Most pathogens enter the body through the mucous membranes lining the digestive, respiratory, urinary, and reproductive system (are these systems open or closed?)  The Second Line of Defence – Non-Specific, Cell-Mediated Immunity ➔ Inflammation – non-phagocytic leukocytes (white blood cells) arrive at the site of infection and release histamines. ◆ Histamines cause the blood vessels to dilate and become more permeable to fluid and leukocytes – this results in redness, swelling, and pain. ➔ Fever – some leukocytes release chemicals that stimulate an increase in body temperature to slow the growth of bacteria. Did You Know? People with allergies (hypersensitivity to something in environment) take anti-histamine medication to reduce or block histamines! ➔ Macrophages are white blood cells that kill bacteria using phagocytosis , a process by which they ingest and destroy the bacteria with digestive enzymes. ➔ Macrophages are non-specific – they will engulf any “foreign body” ➔ Dead macrophages and bacteria are visible as pus at the site of infection Immune Cells Eating Bacteria (1:21) https://youtu.be/iZYLeIJwe4w ➔ After a pathogen has been destroyed the macrophage pushes the foreign antigen to its surface – this is called antigen-presenting.  The Third Line of Defence – Specific, Antibody-Mediated Immunity ➔ Antigens = marker molecules found on the surface of pathogens. ➔ Toxins and other substances produced by bacteria can act as antigens. ➔ The body distinguishes between self-cells and pathogens by recognizing antigens. Our own cells have antigens too! ➔ Lymphocytes – WBCʼs that are involved in cell-mediated and antibody-mediated immunity. Divided into two groups: T-Cells B-Cells ➔ Antigen receptors on lymphocytes allow them to recognize foreign antigens directly or from antigen-presenting macrophages. 1. T Cells = Thymus Lymphocytes ➔ Mature in the thymus gland. Four Types: ➔ Helper T cells: recognize the antigen presented by macrophages and give off chemical signals that stimulate T cells to divide and activates more macrophages. ➔ Helper T cells release chemicals and bind to B cells, activating them and providing information about the specific pathogen. Helper T-Cells ➔ Killer T cells , (aka or cytotoxic T cells, bind with infected cells (e.g. cancer and viruses) and destroy them by puncturing holes in their cell membranes (using a protein called perforin). ➔ Suppressor T cells slow and suppress the process of cellular immunity after the infection has been cleared (so that normal cells donʼt get destroyed). ➔ Memory T cells remain in the bloodstream and are able to act quickly if that particular pathogen is encountered again. 2. B cells = Bursa Lymphocytes ➔ Mature in the bone marrow. ➔ Once a B cell is activated by a helper T cell, it enlarges and divides to produce memory B cells and plasma cells. ➔ The plasma cells produce enormous quantities of the same antibody and release these antibodies into the bloodstream. ◆ Antibodies = Y-shaped proteins that recognize and bind to foreign antigens, neutralizing the pathogen. ◆ Antibodies have a shape that is complimentary (specific) to a specific antigen.  Pathogens that have been neutralized by antibodies are easier for macrophages to engulf and destroy. ➔ After the infection has been fought off, memory B cells and antibodies remain in the blood, to fight off future infection by that pathogen. R Immune Response Summary (Text p. 294) E A D T H R O U G H A Mind Map is a great way to summarize your learning. A copy of this one is posted…I recommend recreating it for yourself as you study what you’ve learned. Immunity = ability to resist disease ⚫ Active immunity ⚫ Immunity that is acquired from the body producing antibodies in response to exposure to an antigen. ⚫ Active immunity develops from exposure to the pathogen or through vaccinations ⚫ Passive immunity ⚫ results when a person receives antibodies from another person or animal. ⚫ Does not last as long as active immunity ⚫ Antibodies can cross the placenta during pregnancy and are also present in breast milk.  Skip- DO NOW! Immune System Analogy Blood Types: The ABO System ⚫ Blood types are inherited – each parent has two alleles for blood type, you get one allele from each parent ⚫ Only certain types of blood are compatible with one another because red blood cell membranes carry specific antigens and people produce specific antibodies that will attack RBCʼs that are not your own type ⚫ Agglutination is the clumping of red blood cells that occurs when incompatible blood types are mixed and the antibodies bind to the antigens. ⚫ Agglutinated red blood cells can clog blood vessels, blocking circulation (hence movement of O2 and CO2, nutrients etc.) and causing severe damage to organs. 1 tsp of the wrong blood type could kill a person! Anti-A and/or Anti-B antibodies appear in blood within several months after birth Blood Groups – text p. 296 ⚫ Blood transfusions – you can donate ⚫ RBCʼs ⚫ Plasma ⚫ Platelets ⚫ Whole blood (has to be perfect match to receiver) For RBC donations… ⚫ Which blood type is the “universal recipient” and why? ⚫ Which blood type is “universal recipient” and why? Which type would be “universal plasma donor”?  O A B AB Blood Types – The Rh System ⚫ The Rh factor is another group of antigens found on red blood cells. ⚫ People WITH the Rh antigen are termed Rh positive (Rh+) and they do not produce anti-Rh antibodies. ⚫ FYI: Most people are Rh+ ⚫ People WITHOUT the Rh antigen are termed Rh negative (Rh-) and they can produce anti-Rh antibodies. ⚫ People who are Rh- usually do not have antibodies to the Rh factor, but they may make them when they are exposed to the Rh factor during a blood transfusion or pregnancy. Blood Types with Rh factor FYI: O- is the true universal donor ⚫ Rh- mom gives birth to Rh+ baby – during delivery, mom and babyʼs blood can mix ⚫ Mom now exposed to Rh-antigen on babyʼs RBCs – foreign invader detected!!! ⚫ Mom builds antibodies against Rh-antigen ⚫ Subsequent pregnancy with another Rh+ baby → anti-Rh antibodies from mom may cross placenta and enter babyʼs bloodstream and attack babyʼs RBCs ⚫ Hemolytic Disease of Newborns (HDN) – blood cells swell, rupture = very low RBC count - can lead to brain damage, deafness, death ⚫ Prevent this problem by injecting Rh- mother with antibody preparation at 28th week of pregnancy and within 72 hours after first birth – injection will attack any of babyʼs RBCʼs in motherʼs blood before her body starts immune response and builds any Rh-antibodies Videos from today: https://www.youtube.com/watch?v=HQWlcSp9Sls https://www.youtube.com/watch?v=xfZhb6lmxjk Blood Typing Site - posted to google classroom - work through it and practice identifying the blood types based on how they clump with A, B, and/or Rh antibodies