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43: The Immune System - Coggle Diagram

- - - - Coordinated cycles of heart contraction drive double circulation in mammals
        
        Closer Look
        
        Heart contracts and relaxes in a rhythmic cycle.
        Cardiac Cycle: complete sequence of pumping and filling
        Systole: Contraction phase
        Diastole: relaxation phase
        
        Cardiac Output: Vol. of blood each ventricle pumps per minute. Is determined by two factors, heart rate and stroke volume.
        Heart rate: number of beats per minute
        Stroke volume: amount of blood pumped by a ventricle in a single contraction
        
        4 valves w/n heart prevent back flow of blood, keeping blood flowin gin th right direction. Valves are made of connective tissue, which open from one side.
        Atriioventricular valve (AV): located between atrium and ventricle.
        Semilunar valve: located at the two exits of the heart, pulmonary and aorta.
        
        If blood does flow backward, this is due to a defective valve, which produces an abnormal sound called a heart murmur.
        
        Maintaining a hearts Rythmic beat
        
        Sinoatrial (SA) node: cluster of cells, which act as a pacemaker, setting the rate and timing for the cardiac muscles to contract Produces electrical pulses.
        Electrocardiogram (EKG) measures electrical activity of the heart via electrodes placed on skin.
        
        The impulses from the SA node reach other nodes such as the atrioventricular (AV) node.
    - - Blood vessel structure and Function
        
        ALL blood vessels contain a cavity lined with an endothelium, single layer of flattened epithelial cells. This minimizes the resistance to fluid flow.
        
        Capillaries have very thin walls, consisting of endothelium and surrounding Extracellular layer.
        Exchange of substances between blood and interstitial fluid happens here because the vessel wall are thin enough.
        
        Artiries and veins have walls the consist of two layers of tissue surrounding the endothelium.
        In Arterial walls they are thick, strong, and elastic to accommodate for the blood pumped by the heart at high pressure.
        
        Veins convey blood back to the heart at a lower pressure, thus not requiring thick walls.
      - Blood Flow Velocity
        
        Blood slows as it moves from arteries to aterioles to the mich narrower capillaries.
      - Changes in Blood Pressure during Cardiac Cycle
        
        Arterial blood pressure is highest which the heat contracts during ventricular systole. This pressure is called, systolic pressure.
        Pulse: rythmic bulging of the artery walls w/ every heartbeat.
        Diastolic Pressure: lower but still substantial blood pressure when ventricles are relaxed.
      - Regulation of Blood Pressure
        
        Vasocontriction: smooth muscles in arteriole walls contract, arteriole narrows. Increases blood pressure upstream in the arteries.
        Vasodilation: increase in diameter that causes blood pressure in arteries to fall.
      - Capillary Function
        
        Blood flows through only 5-10% of the body’s capillaries. Each tissue will have many capillaries, supplying blood at all times.
        
        How is blood flow in capillary beds altered?
        
        One mechanism is via constriction or dial action of the arterioles that supply capillary beds.
        The other is by precapillary sphincters, rings of smooth muscle which regulate the passage of blood into particular sets of capillaries.
      - Fluid return via the Lymphatic System
        
        Adult human body loses 4-8 L of fluid from the capillaries to surrounding tissue. The lost fluid and the blood proteins w/n it are recovered and returned to the blood via the lymphatic system.
        Recovered fluid is called lymph.
        
        Movment of lymph from peripheral tissues to the heart relies on lymph vessels, similar to cardiovascular mechanisms.
        Lymph vessels, like veins, have valves which prevent back flow of fluid. Defective valves can result in edema, swelling.
        Along a lymph vessels are small, lymph-filtering organs called lymph nodes, which play an important role in the body’s defense.
    - - Blood Composition and Function
        
        Plasma: liquid matrix, suspending cells that making up connective tissue.
        Dissolved in the plasma is ions and proteins that, function in oso optic regulation, transport, and defense.
        Plasma also contains many other substances in transit like, hormones, nutrients, metabolic wastes, and respiratory gases.
        Although similar, plasma has higher protein concentration than interstitial fluid.
        
        Two classes of blood cells: Red blood cells, which transport oxygen, and white blood cells, which function as defense.
        Blood contains platelets, cell fragments that are involved in the clotting process.
        Erythrocytes, red blood cells, function to transport oxygen.
        Hemoglobin, the iron-containing protein which transports oxygen.
        When hemoglobin has an abnormal shape, this is called sickle cell disease. This impairs the function of the circulatory system, prevent the delivery of oxygen and nutrients and removal of carbon dioxide and wastes.
        5 types of White blood cells, leukocytes, work to defend against mirror organisms and foreign substances in the blood.
        
        Stem cells: can reproduce indefinitely, located in red marrow inside of bones.
        Erythroprotein (EPO): hormone that stimulates the generation of more erythrocytes.
      - Cardiovascular Disease
        
        Thrombus: blood clot
        Artherosclerosis: hardening of the arteries by accumulating fatty deposits.
        Heart Attack: myocardial infarction, damage or death of cardiac muscle tissue from a blockage of coronary arteries.
        Stroke: death of nervous tissue in the brain due to lack of oxygen.
        Hypertension: high blood pressure, contributes to strokes and heart attacks
    - - Gas exchange along respiratory surfaces
        
        Gas exchange: gas undergoes net diffusion
        Partial Pressure: high concentration to low concentration
        Air is more conductive than water to gas exchange
        
        Structure/Orginazation of respriatory surfaces will differ between animal species.
        
        In aquatic animals, gills are more common. Gills are folds on the outside of the body that are specialized for gas exchange in the water.
        Effectiveness is increased by ventilation, and counter current exchange between blood and water.
        
        In insects, gas exchange is done through a tracheal system. This is a branched network of tubes that bring Oxygen to cells directly.
        Spiders, land snails, and most terrestrial vertebrates have internal lungs.
        
        In mammals, air is inhaled through nostril passages to the trachea, bronchi, bronchioles, and dead end alveoli, where gas exchange occurs.
        
        Lungs: localized respiratory organs
        Larynx: upper part of respiratory tract
        trachea: windpipe
        Bronchi: trachea’s branches leading to each lung
        Bronchioles: w/n the lung the bronchi branch off further in to finer tubes
        Alveoli: air sacs clustered at the tips of the tiniest brochioles where gas exchange occurs.
    - - Respriatory pigments: proteins that circulate with the blood/hemolyph and are often contained within specialized cells.
        They greatly increase the amount of oxygen that can be carried in the circulatory fluid.
        
        Hemoglobin, myoglobin and hemocyanin.
        hemoglobin is great for delivery of Oxygen to tissues that are consuming Oxygen.
        Myoglobin is better for diving mammals which may need to store oxygen for longer periods of time.
    - - Circulatory systems exchange surfaces with cells in the body, which is done by diffusion.
        
        Unicellular organisms exchange directly through the plasma membrane to external enviroment.
        Multicellular organisms have two basic methods.
        
        Simple body plan: many or all cells are placed in direct constancy with environment, allowing each cell to exchange materials directly.
        
        Circulatory system is linked to the exchange of gases with the environment and body cells.
        
        Molecules in and around cells, like oxygen and carbon dioxide, undergo random thermal motion, aka Diffusion.
        Different kinds of organisms do this in different ways.
      - Gastrovascular Cavities
        
        Animals with a simple body plan, allowing for direct contact and exchange with the environment, have a Gastrovascular cavatity.
        
        Gastrovascular Cavity: functions in the distribution of substances throughout the body
        
        This bathes both inner and outer tissue layers in a fluid, allowing for exchange of gases and cellular waste.
      - Open and Closed Circulatory Systems
        
        Contains 3 basic components: circulatory fluid, interconnecting vessels, and a heart.
        
        Heart: muscular pump which powers circulation by using metabolic energy to elevate the circulatory fluids hydrostatic pressure. This fluid then flows through the vessels and back into the heart.
        
        Transportation of fluid though out the body, allows the circulatory system to connect the aqueous environment of the body cells to the organs that exchange gases, absorb nutrients, and dispose of waste.
        
        Open Circulatory System: Circulatroy fluid, Hemolymph, is also the fluid which bathes the body cells
        
        Arthropods and some mollusks, have this.
        Contraction of heart, pumps Hemolymph throughout the circulatory vessels into spaces surrounding the organs,
        
        Advantages: Uses less energy, better for smaller or less active animals
        
        Closed Circulatory System: circulatory fluid, blood, is confined to vessels and is distinct from interstitial fluid.
        
        One or more hearts pump blood into large vessels that branch into smaller vessels, infiltrating tissue and organs.
        Chemical exchange occurs between the blood and interstitial fluids, and between interstitial fluid and body cells.
        
        Advantages: high enough blood pressure allows for more effective delivery of Oxygen and nutrients in larger and more active animals.
      - Organization of Vertebrate Circulatory Systems
        
        Cardiovascular System: describes the heart and blood vessels in vertebrates. Blood circulates though extensive network of vessels.
        
        3 main types of blood vessels: Arteries, Veins, and Capillaries
        
        Arteries: carry blood from the heart to organs.
        These branch into arterioles, smaller vessels which carry blood to capillaries
        
        Capillaries: microscopic vessels with very thin, porous walls.
        Capillary beds: network of capillaries, which infiltrate tissues.
        Capillaries converge into venules, which converge into veins, vessels that carry blood back into the heart.
        
        Hearts of all vertebrates have either two or more muscular chambers
        
        Atria: receive blood entering the heart
        
        Ventricles: pump blood out of the heart
      - Single Circulation vs Double CIrculation
        
        Single Circulation: blood travels through the body and returns to its starting point in a single circuit (loop)
        
        Heart has two chambers: an atrium and a ventricle. Blood entering the heart collects in the atrium before transfer to the ventricle
        
        Double Circulation: two circuits of blood flow to a single organ.
        
        In one circuit: right side of heart pumps oxygen-poor blood to the capillary beds of gas exchange tissues.
        In the other circuit: left side of heart pumps oxygen-enriched blood from the gas exchange tissues to capillary beds in organs and tissues throughout the body.
        Provides vigorous flow of blood to the brain, muscles, and other organs because the heart repressurizes the blood after it passes through the capillary beds of the lungs or skin.
    - - Animals breathe in different ways from each other.
        Some use positive pressure breathing, which forces air down the trachea. Amphibians operate this way.
        Some use negative pressure breathing, which inflate the lungs via pulling air into the lungs when the rib muscles and diaphragm contract. This is done by mammals.
      - Diaphram: sheet of skeletal muscle that forms the bottom wall of the cavity.
        tidal volume: vol. of air inhaled and exhaled with each breath
        vital capacity: tidal volume during maximal inhalation and exhalation
        residual volume: air the remains after a force exhaltaion
      - Air is regulated by involuntary mechanisms, which ensure that gas exchange is coordinated.