Transcript Blood
Bio 257 Day 35 Today’s topics: Ch 11 Blood Ch 13 Blood vessels Circulatory System CV System blood blood vessels heart Lymphatic System Lymphatic organs Lymph Lymphatic vessels Blood • Functions: – Transports = O2,CO2, nutrients, hormones, wastes – Regulates = pH, body temp., osmolality, ions – Protects = against blood loss, foreign microbes & toxins Blood • Characteristics: - more viscous than water – pH 7.35-7.45 – 5-6 liters – divided into 2 components or portions Blood • 2 Components: 1.Formed elements = cells & cell fragments ( 45%) 2. non-formed elements = non-cellular, plasma (55%) Red Blood Cells An important measurement involving RBCs is the hematocrit. The hematocrit is the ratio of blood cells to plasma (ie packed red blood cells). It’s reflective of the body’s O2 carrying capacity. What’s the hematocrit in the sample below? Blood • Blood A)is a type of epithelial tissue. B)consists of formed elements only. C)transports waste products to cells. D)makes up over 50% of the body's weight. E)has a total volume of approximately 5 liters. Plasma • Characteristics: 1. straw-colored 2. 91.5 % water & 8.5 % dissolved solutes (including CO2) 3. Some solutes are plasma proteins Plasma • 3 types Plasma Proteins: 1. albumin 2. globulins 3. fibrinogen Plasma Proteins • Albumin: 1. Most abundant 2. Synthesized by liver 3. Function: maintains blood’s osmotic pressure (water movement between tissue & blood) to maintain blood volume Plasma • The major component of plasma is A)ions. B)proteins. C)water. D)gases. E)nutrients. Plasma Proteins • Globulins: 1. produced by liver 2. 3 types (alpha, beta and gamma) 3. alpha & beta globulins fxn = transport fat and fat-soluble vitamins Plasma Proteins • Globulins: 4. Gamma globulins also called immunoglobulins or antibodies – fxn to protect and provide immunity Plasma Proteins • Fibrinogens: 1.fxn = blood clot formation Chem. Rx: Clotting factors Prothrombin ------ thrombin thrombin Fibrinogen ---- fibrin threads for clot Injury to vessel and exposure of connective tissue to exposed chemicals (thromboplastin) starts the clotting cascade Plasma Proteins Plasma proteins A)include albumin, globulins, and fibrinogen. B)are a major factor in determining osmotic pressure of blood. C)are responsible for clot formation. D)include antibodies and many other chemicals that function in immunity. E)have all of these properties. Formed Elements • Include: – White blood cells= leucocytes – Red blood cells= erythrocytes – Platelets = thrombocytes • Form a platlet plug when a break in a BV occurs. • trigger-collagen exposed by BV damage Formed Elements • Leucocytes (wbc’s) – – – – 5 kinds Nucleated (polymorpho-nucleated) Larger but less numerous than rbc’s Fxn • 1 protect against invading microbes • 2 remove dead cells/debris from tissues – Divided into 2 categories Formed Elements • Leucocytes (wbc’s) – 2 categories 1.Agranulocytes = cytoplasm w/o granules 2.Granulocytes = cytoplasm w/ granules Leucocytes (wbc’s) • Agranulocytes (2) – Lymphocytes = large nucleus(2/3), provide immunity 1. 2 kinds lymphocytes T lymphocytes B lymphocytes (antibodies) Leucocytes (wbc’s) • Agranulocytes (2) 2. Monocytes = round, kidney- shaped or lobed nucleus 1. phagocytic wbc’s 2. can enter tissues = -diapedisissqueeze b/w cells that form BV walls -outside blood move in the spaces b/w cells by amoeboid motion Here we see a WBC squeezing its way out of a blood vessel – in other words, performing diapedesis. Damaged Cell WBC WBC Releases chemicals that attract WBCs (known as chemotactants). WBC WBC WBCs converge on the area – i.e., they exhibit positive chemotaxis. They then release more chemotactants to attract more WBCs. Leucocytes (wbc’s) • Granulocytes (3) – Neutrophils = pink granules (phagocytic) – Basophils = blue granules • release histamine/heparin – Eosinophils= red granules • Release chemicals to dec inflammation and attack worm parasites In this picture, find: RBCs, 2 neutrophils, an eosinophil, a basophil, a monocyte, a lymphocyte, and a platelet. Never Neutrophils Let Lymphocytes Monkeys Monocytes Eat Eosinophils Bananas Basophils Leucocytes (wbc’s) The white blood cells called granulocytes are A)erythrocytes, thrombocytes, and megakaryoblasts. B)monocytes, macrophages, and neutrophils. C)neutrophils, basophils, and eosinophils. D)lymphocytes and monocytes. E)thrombocytes, monocytes, and macrophages. Erythrocytes (rbc’s) • Characteristics – Biconcave discs = thin center & thick edges – Flexible – Life span 120 days – No nucleus – Smaller than wbc’s but more numerous - Main component is pigmented protein called hemoglobin CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. Erythrocytes (rbc’s) • Function – Transport oxygen and carbon dioxide by hemoglobin – Hemoglobin = 4 globin and 4 hemes (Fe2+), (carries 4 O2) Note: hemoglobin molecules rbc Erythrocytes (rbc’s) • Function – O2 binds to iron of the hemoglobin – CO2 binds to globin or rbc’s converts it to H2CO3 then bicarbonate and H+ Note: Too much CO2 causes acidosis pH < 7.35 (Hypoventilation) Erythrocytes (rbc’s) • Function – Types of hemoglobin 1.Oxyhemoglobin = hemoglobin w/ O2, bright red (arterial blood) 2.Carbaminohemoglobin= hemoglobin w/ CO2 dk. red (venous blood) Note the 4 heme groups associated with the 4 polypeptide chains of the hemoglobin protein. Each has an iron in its center. How many O2 molecules could a single hemoglobin carry? Erythrocytes (rbc’s) • Function – Types of hemoglobin 3. Carboxyhemoglobin = hemoglobin w/ CO, pink Erythrocytes (rbc’s) • Function – 4 Blood Types 1. ABO blood Groups A blood type B blood type Ab blood type O blood type Erythrocytes (rbc’s) • Function – 4 Blood Types 2. Determined by cell markers or receptors on rbc membrane called antigens - A antigens - B antigens - no A or B antigens Erythrocytes (rbc’s) Blood Types Antigen Type A blood A antigens Type B blood B antigens Type AB blood A & B antigens Type O blood No A or B antigens Plasma • Contains antibodies which bind to blood antigens and cause agglutination clumping of rbc’s • A person has opposite antibodies to their antigens Blood A blood Antigen (on RBC) A antigens Antibodies (in plasma) Anti-B antibodies B blood B antigens Anti-A antibodies AB blood A&B antigens No anti-A or B antibodies O blood No A or B antigens Both anti-A & B antibodies Plasma • Rh factor • presence of Rh antigens on surface of RBC Rh + • absence of Rh antigens on RBC Rh- Erythroblastosis • hemolytic disease of newborns • develops when: • mother (Rh-) X father (Rh+) fetus Rh+ Erythroblastosis • mother (Rh-) w/ fetus Rh+ • any fetal blood leaking to mother is enough for her to produce Rh antibodies • Rh antibodies agglutinate fetal blood • RhoGAM – shot inactivates Rh antigen Hemolytic Disease of the Newborn (HDN) Blood • Hematopoeisis-blood cell production • All blood cell production occurs in the red bone marrow, which is found in the: – Axial skeleton – Pelvic and pectoral girdles – Proximal epiphyses of the humeri and femurs. • All blood cells are made from stem cells. Hematopoiesis Red Blood Cell Production erythropoeisis = red blood cell production, requires a hormone from kidney called erythropoietin Consider K2 – the mountain below. – How would spending time on its upper slopes affect your body’s EPO levels? – How would it affect your blood viscosity? Platelets • thrombocytes = cell fragments • produced from megakarocytes that shed their cytoplasm (large cells) • normally repel each other,unless activated • function = hemostasis (stoppage of bleeding) Hemostasis • 3 steps (upon damage to blood vessel) Step 1: Vascular Spasm = smooth muscle in blood vessels constricts to reduce blood loss Hemostasis • 3 steps (upon damage to blood vessel) Step 2: Platelet plug = platelets stick to injury site and each other forming a plug Hemostasis • 3 steps (upon damage to blood vessel) Step 3: Blood clot formation = activated fibrin threads form a meshwork around plug, condensing it to a clot Clot dissolution • fibrinolysis by enzyme, plasmin •prevents unwanted clots b/c blood contains anticoagulants heparin (basophils) antithrombin (liver) RBC’s Erythrocytes A)are biconvex disks. B)have several nuclei in each cell. C)divide frequently. D)contain large quantities of hemoglobin. E)have all of these properties. Circulation • Heart provides the major force for circulation of blood • Peripheral Circulation fxn: – Carry blood- Hearttissuesheart – Exhange nutrients,waste,gases • Nutrients and oxygenBlood vessel (BV) to cells • Wastes and carbon dioxidecells to BV – Transport-hormones, immune mediators, clotting factors, enzymes, nutrients, gases, waste products… – Regulate BP by heart and circulation working together – Direct flow to tissues when increased blood flow is required Features of Blood vessels • Arteries carry blood away from the heart – decrease in diameter an increase in # as they project away from the heart – Repeated branching eventually leads to arterioles • Blood flows from the arterioles to capillariesthin walls allow for exchanges (nutrient and wastes) to occur b/w blood and tissue fluids. – Precapillary sphincters regulate flow through capillary networks • Blood flows from the capillaries to veins and returns the blood to the heart – Veins (thinner walled structures than arteries) increase in diameter and decrease in # as they project towards the heart. Blood vessel structure • 3 layers (except in capillaries and venules) – Tunica intima (innermost layer) • Endotheliumsimple sq epithelium, basement membrane and small qty of connective tissue – Tunica media (middle layer) • Contains variable qty’s of elastic and collagen fibers – Tunica adventitia (outer layer) • Denser connective tissue adjacent to tunica media and more loose connective tissue towards the outer portion of the BV wall Blood vessel structure Blood vessel structure Capillary wall Capillary wallsimple squamous epi. allows exchange of gases, nutrients and wastes Capillary network Smooth muscle cells (precapillary sphincter) regulate flow through the capillaries. flow increasesdilation flow decreaseconstriction Circulatory system (blood flow) Rt atriumRt ventriclepulmonary trunk pulmonary arterieslung capillaries (lose CO2 and gain O2)Lt atriumLt ventricle Aortaarteries (to all of body)tissue capillariesVeins (back to heart) Blood psi • BP-measure of force blood exerts against the blood vessel walls. – In arteries exhibits a cycle dependency on the rhythmic contractions of the heart (i.e., heart contracts and psi increases and as heart relaxes blood perfuses through tissues) – Systolic psi-ventricles contractblood forced into arteriespsi maximum – Diastolic psi-ventricles relaxbp in arteries falls to a minimum value – Measured in mm Hg (100 mm Hg psi great enough to lift a column of mercury 100 mm) Blood psi measurement When cuff psi exceeds Brachial artery psino sound Systolic psifirst sound heard when brachial artery psi exceeds cuff pressure during systole (turbulent flow) Diastolic psipsi when sound disappears. When cuff psi decreases below the psi in the brachial artery and remains open during systole and diastole. (Nonturbulent flowno sound) Capillary exchange 1. BP > osmotic driving force 2. Osmotic driving force > BP 3. 0.9 of fluid that leaves the arterial end reenters at the venous end. 0.1 of the fluid passes into the lymphatic capillaries Local Blood Flow Control Dilation-inc. blood flow Constriction-dec. blood flow Nervous regulation of blood vessels Vasomotor center regulates the frequency of action potentials in nerve fibers innervating blood vessels. Increased firing rate vasoconstriction Decreased firing rate vasodilation Baroreceptor reflex 1.Baroreceptorsdetect change in bp 2. Impulses sent to cardioregulatory and vasomotor centers 3.Increased release of ACh from Vagus nerve dec. HRoccurs in response to inc. BP 4.Increased release of Norepi inc. HR and stroke volume (volume per beat)occurs in response to dec. BP 5.Increased Norepi release increases vasoconstrictionoccurs in response to dec. BP Net effect-responses keep bp in normal Range. Chemoreceptor control of BP 1.Chemoreceptors monitor 02 CO2 and pH in blood 2.Chemoreceptors in the medulla Monitor CO2 and pH 3.Dec O2 and inc C02 and dec pH decrease in ACh release. Norepi release predominates. 4.Dec O2, inc CO2 and dec pH increases Norepi release increases HR and Stroke volume 5.Dec blood O2, inc CO2 and Dec pH inc Norepi release and increases vasoconstriction Net effect: inc BP, greater Blood flow through lungs, inc O2, dec CO2. Fxn under emergency conditions Triggered when O2 falls very low or when CO2 becomes sig elevated Hormonal Regulation of BP 1. Dec O2, inc CO2 dec pH, stress fight or flight responses inc impulses to medulla O. 2.Impulses via descending pathways increases Epi and some Norepi. release from A.medulla Net effect: inc ventilation, inc O2, dec CO2, inc pH, shunting of blood from viscera to sk. muscle Renin-Angiotensin-Aldosterone Mechanism (hormonal regulation) 1. Dec. BP detected by Kidneys inc renin secretion 2.Renin converts Angiotensinogen to Angiotensin I (AI) 3.Angiotensin-converting Enzyme (ACE) converts AI to Angiotensin II (AII) 4.AII inc. BP by vasoconstriction 5.AII stimulates Adrenal cortex to secrete aldosterone 6.aldosterone inc. Na+ reabsorption inc. blood vol., dec. urinary vol inc. BP Vasopressin (ADH) mechanism (hormonal regulation) Triggers- inc. osmolality, dec. BP ADH secretion. ADH inc. water reabsorption back into the vascular space or bloodstream. Large amounts of ADH vasoconstriction. Net effect: maintain blood psi Control of BP (slow-acting/long-term) Atherosclerotic plaque Arteriosclerosis(Artery) changes in arteries that make them less elastic, less compliant Atherosclerosisresults from deposition of material in the walls of arteries to form plaques. The material contains cholesterol and can eventually be dominated by deposition of dense connective tissue and Ca++ salts