Human Anatomy and Physiology II - Lecture notes - 1. Blood PDF

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Blood Cardiovascular System:  Functions to act as a transport mechanism for the human body o Provides nutrients (macro and micronutrients) to muscles o Gases, such as oxygen and carbon dioxide, are carried through the CV system carbon dioxide is an end product of metabolism that is exchanged enzymes combust nutrients with gases in order to fuel the body o Transports end products of metabolisms (ex. hormones)  Components of CV system o Heart is the central pump produces a force to generate movement of blood throughout the system  Cardiac muscles functions as an energy generator and consumer o Blood vessels (vasculature) are extensions of the heart (cardiac muscles) throughout the body  The CV system is a closed loop of vessels and in order for things to get in and out of the system they must diffuse through the cell walls of blood vessels o Blood is the fluid contained within the CV system that circulates the molecules  Slide 19.3 19.1- Functions of Blood  Transport gases, nutrients and waste products o Oxygen, carbon dioxide and metabolic end products o Glucose, amino acids, fatty acids and vitamins o Urea, uric acid, creatinine, ammonia are end products that can be toxic so they CV rid itself of these substances through diffusion o Bilirubin is the breakdown product of red blood cells o Lactic acid is the end product of anaerobic respiration and is converted into glucose by the liver  Transport of processed molecules (ex. vitamin D precursor from skin to liver and kidney)  Transport of regulatory molecules (ex. hormones from the endocrine glands to the rest of the body)  Regulation of pH o Normal blood pH is between 7.35 and 7.45 o Intense exercise makes the blood a more acidic environment this leads the blood to buffer protons protons come from the lactic acid produced from the increased glucose breakdown  Maintenance of body temperature o Core temperature must stay as steady as possible while even if skin is hot and sweating kidney is most susceptible to heat-related injuries

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o Heat transfer from muscle tissue to blood to skin to the external environment o When we exercise we sweat in order to internally rid ourselves of the heat generated from metabolically active muscles blood flows through muscles and collects the heat then gets rid of it through the skin/sweat Protection against foreign substances o Antibodies are produced in the blood in response to infection and pathogens Clot formation o As we move the blood vessels compress and causes small lesions our blood has a built in self repair mechanism to fix these damaged tissues

Composition of Blood:  8% of total body weight is blood (approx 4-6L in adults)  Plasma makes up 55% of blood: o Proteins 7% (albumins, globulins, fibrinogen) o Water 91% o Other solutes 2% (ions, nutrients, waste products, gases, regulatory substances)  Formed elements makes up 45% contains platelets (250-400 thousand), 4.26.2 million RBC and white blood cells, 5 types: o Neutrophils 60-70% o Lymphocytes 20-25% o Monocytes 3-8% o Eosinophils 2-4% o Basophils 0.5-1% Plasma:  Liquid part of blood 91% water and 9% proteins, ions, nutrients, waste products, gases, regulatory substances o Contains colloid, suspended substances, which allow for solutes to be dissolved in fluids  Proteins in the plasma: o Albumins are the most abundant (58%) and help with transportation of fatty acids, thyroid hormones and osmotic pressure (draws water from extracellular places so this protein regulates the fluid pressure) o Globulins (38%) transports lipids, some carbohydrates, hormones, ions and antibodies o Fibrinogen (4%) aids with blood clotting because it forms a mesh network over lesions in the CV system Formed Elements:  Red blood cells, erythrocytes, make up 95% of formed elements

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o Shaped as bioconcave discs with no nucleus or mitochondria this means they cannot self repair or adapt (don’t live very long) also they use anaerobic metabolism because they cannot use oxygen (no mitochondria) o Contain hemoglobin to transport oxygen to tissues and carbon dioxide from tissues o Converts carbon dioxide and water to carbonic acid (H2CO3)  Does this through carbonic anhydrase  Carbon dioxide and water are products of anaerobic metabolism need to get rid of these so they don’t build up in the blood White blood cells, leukocytes, make up 5% of formed elements o Granulocytes have large granules and multi-lobed nuclei can proliferate in response to infection have three distinct types:  Neutrophils  Eosinophils  Basophils o Agranulocytes have small granules and nuclei that are not lobed neutralize foreign pathogens have two distinct types:  Lymphocytes  Monocytes Platelets (thromocytes) o Cell fragments with cell membranes o Form platelet plugs in response to lesion this sticks to exposed part of CV system and signals release of chemicals necessary for blood clotting Slide 19.10 Hematopoiesis (hemopoiesis) is the process of blood cell production o Pre-birth all tissues do this but post-birth only red bone marrow and the lymphatic system do o Stem cells are all the formed elements derived from a single population (hemocytoblst) differentiates into proerythroblasts (red blood cells), myeloblasts (basophils, neutrophils and eosinophils), lymphyoblasts (lymphocytes), monoblasts (monocytes) and megakaryoblasts (platelets) o Slide 19.11 Red blood cells o 5.4 million/microlitre in adult men and 4.8 million/microlitre in adult women o 1/3 hemoglobin and 2/3 lipids/ATP/carbonic anhydrase o Transport functions:  Oxygen 98.5% is bound to hemoglobin and 1.5% is dissolved in plasma  RBC oxygen vs. Plasma oxygen RBC oxygen is more important because oxygen consumption because there is so much muscle tissue

Carbon dioxide 23% is bound to hemoglobin, 7% dissolved in plasma and 70%as bicarbonate (conjugate base to carbonic acid)  H+ generated from carbonic anhydrase reaction o Hemoglobin is the quaternary protein structure that has 4 components (globin beta1/2 alpha 1/2)  1 oxygen is bound to each heme (iron) and there are 4 heme’s per hemoglobin= 4 oxygen/hemoglobin under resting conditions we only really need to use one oxygen so when we start exercising or moving out cells can then use more oxygen as the metabolic rate increases  Oxyhemoglobin is a hemoglobin that is fully saturated with oxygen (all 4 binding sites)  Deoxyhemoglobin is a hemoglobin with no oxygen bound to it  Carbaminohemoglobin is a hemoglobin with carbon dioxide found to it (occurs in the blood leaving tissues)  Hemolytic anemia is when a low RBC count leads to low blood oxygen and thus a decreases ability to deliver oxygen  Factors affecting RBC count: autoimmune, enzyme deficiency, free radical accumulation 

Erythropoiesis:  2.5 million red blood cells are degenerated per second but there are 25 trillion red blood cells in the circulation they last about 120 days in circulation  Erythropoiesis is the production of red blood cells time required to produce a single RBC is about 4 days  RBC production is stimulated by low blood oxygen levels, which result from a number of conditions: o Decreased number of RBC (can be due to loss of blood/hemorrhaging, which typically requires a donation of about 8-10%) o Decreased/defective hemoglobin o High altitude creates a hypoxic environment oxygen molecules are spread out therefore it is harder for us to get the oxygen into our blood o Increased demand for oxygen (ex. during exercise)  Low blood oxygen levels stimulate erythropoiesis by increasing formation of erythropoietin, a hormone produced by the kidney, which stimulates the bone marrow to make more RBC o 98.5% of oxygen in CV system is in our RBC so if we loose RBC it will cause oxygen levels to decrease= stimulating body to make more RBC o Decreased oxygen= decreased RBC because they carry oxygen o This is an inhibitory process (when oxygen is present erythropoiesis does not occur) o Slide 19.14  Cell division requires folate, b12, iron and vitamin C o Folate and B12 are required to DNA synthesis o Iron is required for hemoglobin production o These activate enzymes that are required for production of RBC  More RBC= greater oxygen carrying capacity o Athletes may want to do this in order to be able to increase oxygen transportation to muscle therefore increase exercise intensity and endurance  Darbepoetin alfa-albumin (Aranesp) is a drug used to treat anemia through activating the bone marrow to make more RBC o Boosts body’s natural mechanism o Can treat anemia caused by kidney disease (don’t make the erythropoietin) or cancer treatments Hemoglobin Breakdown:  Slide 19.16  Hemoglobin is broken down by macrophages into heme and globin chains  Globin chains are broken down into amino acids and are metabolized/used to build new proteins (red arrow)  Heme releases the iron and the iron-free heme is then converted to biliverdin converted to bilirubin (chemical group) transported to the liver where it becomes part of bile, which aids in fat emulsification (blue arrow)

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The iron that was taken off of the heme is combined with transferring and recycled to various places (liver, spleen and bone marrow) for storage and making new hemoglobin (green arrow)

White Blood Cells (leukocytes):  These form the thin, white layer known as the buffy coat  WBC protect the body against microorganism and remove dead cells/debris lack hemoglobin but are nucleated therefore allowing them to proliferate when the body needs (ex. if body is invaded by pathogens)  Movements of WBC: o Ameboid has pseudopods that are extensions of their membranes (false feet) that allows them to move across surfaces and engulf particles o Diapedesis cells become thin, elongate and move either between or through endothelial cells of capillaries capillaries are essentially only endothelial cells therefore WBC can move out of CV through them and then enter tissues to attack pathogen or health tissues (this happens in autoimmune diseases such as DM Type 1) o Chemotaxis attraction to and movement towards foreign materials or damages cells accumulation of dead WBC and bacteria is pus  How does a WBC know if a cell is bad or damages? o Injured/damaged cells release chemoattractants, such as cytokines (proteins), that will drawn WBC to them o Cytokines as a stress signal and initiate a pro-inflammatory response in the tissue  WBC have increased energy demand when we are sick therefore eating carbs when we are sick is good provides the extra energy to these WBC in order for them to metabolize the carbs to fuel their increased metabolic rate/more cells  Neutrophils o Most abundant WBC (60-70%) o Tri/multilobed nuclei o Last about 10-12 hours in circulation after which they leave the CV system and last about 1-2 days in tissues o When they enter tissues:  Seek out and phagocytize bacteria surround and engulf bacteria  Secrete lysozymes which is an enzymes that is capable of destroying/metabolizing certain bacteria that they engulf o These are pro-inflammatory  During muscle injury they will become inflamed problem is if they are stuck in this stage of inflammation and the tissue cannot heal  Eosinophils o 2-4% of WBC o Often have a two lobed nucleus

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o Active in allergic reactions destroy inflammatory chemicals like histamine in order to reduce inflammation o Release chemicals that help destroy tapeworms, flukes, pinworms and hookworms Basophils o 0.5-1% of WBC o Increase in number for allergic and inflammatory reaction o Produce histamine that increase vasodilatation and bronchial constriction (restricts smooth muscle and breathing decreases) o Produce heparin, which inhibits blood clotting deactivates factors that would normally lead to formation of clots Lymphocytes o 20-25% of WBC o Smallest WBC (just slightly larger than RBC) o Originate in red bone marrow but they migrate through blood to lymphatic tissues (lymph nodes, spleen, tonsils, lymphatic nodules and thymus) where they proliferate to make more lymphocytes o Produce antibodies, which are proteins that destroy bacteria/cells with viruses/tumor cells Monocytes o 3-8% of WBC o Largest WBC o Remain in circulation for about 3 days after which they leave and turn into macophages they migrate into various tissues and phagocytize bacteria, dead cells, cell fragments and other debris o Monocytes typically increase with chronic infection o They are involved with CV disease because they try to regulate fat in the CV but they fat overtakes it and it can become artherosclerotic plaque

Platelets/Thrombocytes:  These are cell fragments pinched off from megakaryocytes, in red bone marrow, and enter circulation as platelets  Life expectancy is about 5-9 days  Surface glycoproteins allow these molecules to adhere to other molecules (ex. collagen) good if trying to repair lesions but too much of these can put you at risk for heart attacks or strokes  Platelets are important in preventing blood loss: o Form platelet plugs these are accumulations of platelets at blood vessel ‘breaks’ o Promote formation and contraction of clots they are release a chemical (fatty acid derivative) that will recruit more platelets to the break site (too much of this enzyme will cause a clot)...