Biol 2030 lec exam two

functions of the circulatory system

• @@circularity system@@: consists of the heart, blood, and blood vessels
• @@cardiovascular system@@: refers to only the heart and blood vessels
• Functions of the circulatory system:

     1. TRANSPORT- ^^O2^^, CO2, Nutrients, wastes, hormones, stem cells   2. PROTECTION- inflammation, limit the spread of infection, destroy cancer cells, neutralize toxins, and initiate clotting.   3. REGULATION- Fluid balance, stabilizes pH or ECF, and temperature control.

Components of blood

• adults have 4-6 L of blood
• Liquid connective tissue: cells and extracellular matrix
• @@Plasma@@: Matrix of blood, clear light yellow fluid
• Formed elements: blood cells (red, white, and platelets)
• Hematocrit- centrifuge blood to separate components

  $*Erythrocytes settle first and are heaviest, white blood cells and platelets are only 1$

7 kinds of formed elements

1. @@Erythrocytes@@: Red blood cells

• @@Platelets@@: cell fragments from special cells in bone marrow

  @@Leukocytes@@: White blood cells. Divided into two categories   * GRANULOCYTES (with granules)   * \          3. @@Neutrophils@@   * \          4. @@Eosinophils@@   * \          5. @@Basophils@@ \n   * AGRANULOCYTES ( Without granules)   * \          6. @@Lymphocytes@@   * \          7. @@Monocytes@@ \n

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Blood Plasma

• @@Plasma@@- liquid portion of blood   * serum: remaining fluid when blood clots and solifs are removed identical to plasma except for absence of fibrinogen (holds blood clots together)
• Three major categories of plasma proteins   * ^^Albumins^^ : Smallest and most abundant; influences blood pressure, bloodflow, an fluid balance   * ^^Globulins^^ (antibodies): provide immune functuons   * ^^Fibrinogen^^: precursor of fibrin threads that help form blood clots

$*formed by liver (liver makes proteins)$

• dissolved O2, CO2, and Nitrogen electrolytes.

Blood Viscosity and Osmolarity

• @@Viscosity@@: Resistance of a fluid to flow, resulting from the cohesion of its particles   * whole blood 4.5-5.5 times as viscous as water   * Plasma is 2.0 times as viscous as water
• @@Osmolarity@@: total molarity of those dissolved particles that cannot pass through the blood vessel wall. (measure of solute inh a solution) -Water always diffuses from low to high   * if to high, blood absorbs too much water, increasing the blood pressure   * if to low, to much water stays in the tissue, blood pressure drops, edema occurs   * optimum osmolarity is achieved by bodys regulation of sodium ions, proteins, and red blood cells

$*Albumen regulates water in blood/tissues$

Starvation and plasma protein deficiency

• Hypoprotenimia: deficiency of plasma proteins   * Extreame starvation   * liver or kidney disease   * severe burns
• Kwashiorkor: children with severe protein deficiency   * Thin arms   * Distended abdomen

How blood is produced

• Adult production of 400 billion platelets, 100-200 billion RBC, and 10 billion WBCs every day
• @@Hemopoiesis@@: production of blood
• @@Hemopoietic tissues@@ produce blood cells   * Yolk sac produces stem cells for first blood cells   * liver stops producing blood cells at birth   * splen remains involved with lymphocyte production
• Red bonme marrow produces all seven formed elements
• @@colony- forming unit@@- specialized stem cells only producing one class of formed element of blood
• @@Myeloid Hemopoiesis@@- blood formation in the bone marrow
• @@Lymphoid Hemopoiesis@@- blood formation in the lymphatic organs

Erythrocytes

• Two principle functions   * carry O2 from lungs to tissues   * Pick up CO2 from tissues and bring to lungs

*inssuificient EBC can cause death in minutes due to lac of oxygen to tiussues

• disk shaped cell with thick rim   * ^^Lack of nucleus^^: no mitosis   * ^^lack of mitocondria^^: anarobic resperitaion   * ^^full of hemoglobin^^ to carry O2
• Gas transport: major function
• O2 must bind to hemogloben
• @@Carbonic anhydrase@@ (CAH) in cytoplasm   * $*found inside red blood cell$   * produces carbonic acid from CO2 and water   * important role in gas transport and pH balance

Hemoglobin

• four protein chains
• four Heme groups each carrying one O2   * nonprotein moiety that binds O2 to Fe at its center   * *1 hemoghloben can bind 4 O2
• @@Men have more RBC and Hemogloblen@@   * women have a menstrual cycle and more body fat

Erythrocyte production

• Erythropoiesis (EPO)- RBC production   * EPO made buy kidneys   * The average lifespan of RBC is 120 days   * development takes 3-5 days
• Production

     1. Pluripotent stem cell   2. Erythrocyte colony-forming unit (committed cell)      * has receptors for EPO from kidneys   3. precursor cells      * Erythroblasts multiply and synthesize hemoglobin      * Reticulocyte discards nucleus to make room for hemoglobin   4. mature cell (Erythrocyte)

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Iron Metabolism

Erythrocyte homeostasis

1. hypoxemia is sensed by the liver and kidneys

2. secretion of EPO from kidneys
3. stimulation of red bone marrow
4. accelerated erythropoiesis (formation of red blood cells)
5. increased RBC count
6. increased O2 transport

• negative feedback control   * Dropped RBC causes Hypox$emia$ (‘emia’ means blood)   * Kidney production of preproprotein stimulates bone marrow

    *erythropoiesis (EPO) is RBC production   * RBC increases in 3-4 days

• Stimuli for increasing EPO   * Low levels of O2   * high altitude   * increase exercise   * loss of lung tissue in emphysema

Erythrocyte death and disposal

• RBC rupture (Hemolysis) in narrow channels of spleen and liver
• macrophages in the spleen (spleen considered RBC graveyard)   * Digests membrane bits   * separates heme from globin

Erythrocyte disorders

• @@polycythemia (High RBC count)@@   * primary polycythemia     * cancer of erythropoietin cell line in red bone marrow     * High RBC count high as ^^11 million^^ RBC   * Secondary polycythemia     * from dehydration, emphysema, high altitude, or physical conditioning     * RBC up to ^^8 million^^   * Dangers of polycythemia     * increased blood volume, pressure, viscosity     * can lead to embolism, stroke, or heart failure
• @@Anemia@@   * inadequate EPO or hemoglobin synthesis   * kidney failure and insufficient erythropoietin     * Hemorrhagic anemias from bleeding     * Hemolytic amenia from RBC destruction   * Dangers     * Tissue hypoxia and necrosis     * pt lethargic, shortness of breath with exertion, necrosis to the brain, heart, or kidney     * blood osmolarity is low, producing tissue edema     * blood viscosity is low, cardiac failure
• @@Sickle cell disease@@   * hereditary defect in mostly African descent (due to malaria)   * differed only on the 6th amino acid on the bata chain   * full carriers usually don’t survive without medical help   * can lead to kidney failure, heart failure, stroke, joint pain, or paralysis

Blood typing

• Agglutinogens are RBC antigens
• Called antigen A and B
• Ditermined by glycolipids on RBC surface
• antibodies are called agglutinins

I is recessive

A is dominant

B is dominant

• RH group: Rh+ is if you have the D antigen
• Rh- people can only receive from other Rh- people but Rh+ can receive from Rh- and Rh+

Hemolytic disease of the newborn

Can occurr if Rh- mother has formed antibodies and is pregnant with a second Rh+

• prevention   * RhoGAM given to prevent Rh- women

WBC form and function

• least abundant formed element
• protects against infectious microorganisms and other pathogens
• conspicuous neculus
• retaint their organelles for protein synthesis
• granules

Types of leukocytes

• granulocytes   * Nutrophils - aggressively antibacterial     * nurtophilia- rise in number of nutrophils in response to bacterial infection   * Eosinphils- releases enzyme to destroy large parasites     * increased numbers in parasitic infections, collagen disease, allergies, and diseases of the spleen   * Basophils- secreasts histamine (speeds flow o blood to an injured area) and Heparin ( promotes mobility of other WBCs in the area.     * increased numbers in chickenpox, sinitis, diabeties.
• Agranulocytes   * Lymphocytes- Distroy cells ( cancer, foreign, and infected cells)     * coordinate actions to other immune cells     * secrete antibodies to provide immune memory     * increased number in diverse infections and immune responses   * monocytes- leaves blood stream to transform into macrophages     * increased numbers in viral infections and inflammation

Leukocyte life history

• leukopoiesis- production of white blood cells
• Hemopoiteic stem cells differeate into:   * myeoblasts- from nutrophils, eosinophils, basophils   * monoblasts- from monocytes   * lymphoblasts- gove rise to all forms of lymphocytes
• red bone marrow stores and releases monocytes and granulocytes

Leukocyte life cycle

• circulating WBC do not stay in blood stream   * granulocytes leave in 8 hours and live 5 days longer   * monocytes leave in20 hours, transform into macrophages, and live several years   * lymphocytes provide long term immunity (decades) being continuously recycled from blood to tissue fluid to luymph back to blood.

Lekocyte disorders

• lueokpenia- low WBC count, below 5,000 WBCs   * causes: radiation, poisons, infectious diseases   * effects: elevated risks of infection
• Leukpcytosis: high WBC count, above 10,000   * causes: infection, allergy, diseases   * differential WBC count: identifies what percentage of total WBC consists of each type of leukocyte.
• leukemia: cancer of hematopoietic tissue usually producing a very high number of circulating leukocytes   * myeloid leukemia: uncontrolled granulocyte production   * Lymphoid lukema: uncontrolled lymphocyte or monocyte production

  ## Platelets

  Small fragments of megakaryocyte

• platelet function:   * secrete vasoconstriction that help reduce blood loss   * stick together to form platelet plugs ( collegon is found under skin layer and is stickey)   * secrete procoagulants to promote clotting   * chemically attract nuetrophils and monocytes to sites of inflammation   * secrete growth factors that stimulate mitosis to repair blood vessels
• Platelet production:   * Thrombopoiesis: Stem cells that becomnme megakaryoblasts   * Megakaryoblasts: repeatedly replicate DNA without dividing   * \

  ## Platelets and hemostasis

• Hemostasis: the cessation of bleeding   * hemorrhage: excessive bleeding
• Three homeostacic mechanisms   * vascular spams   * platelet plug formation   * coagulation ( blood clotting)
• vascular spasm- prompt constriction of a broken vessel.   * causes: pain receptors   * most immediate protection against blood loss
• platelet plug formation- plsayelet psudeopods stick to damaged vessels and other psudeoods contract   * collagen is directly under endotheial tissue and is sticky. platelets stick to collagen.
• Coagulation- clotting. conversion of fibrinogen into fibrin threads framework together   * procoagulants (clotting factors)- usually produced by the liver   * extrenisic pathway- factors released by damaged tissues begin to cascade ( activate one factor and it will activate the next)   * intrinsic pathway Factors found in blood begin to cascade

Caogulation of intrinsic and extrensic pathways

The fate of blood clots

• clot retraction occurs within 30 minutes
• fibrinolysis- dissolution of a clot   * @@plasminogen turns into plasma which dissolves fibrin that breaks up clot@@
• Thre prevention of inappropriate clotting is caused by a prostacyclin coated endothelium

Clotting disorders

• Hemophilia- deficiencies in one factor or another in coagulation   * usually missing Factor 8/VIII   * Physical exertion causes bleeding and pain
• Hematomas- blood colt in the tissues outside of the vessel
• Thrombosis- blood clotting inside a blood vessel
• embolus- anything that can travel in the blood and block blood vessels

Blood vessel anatomy

• arteries- caqrry blood away from the heart
• veins- carry blood to the heart \
• capillaries- connects smallest arteries to smallest veins
• vessel walls   * Tunica interna- inner most layer, lines blood vessels and exposed to blood     * Endthelium- simple squamous epithelium overlaying basement membrane. normally repels blood cells and platelets   * Tunica Media- middle layer that consists of smooth muscle     * regulates diameter of the blood vesssel   * Tunica Externa- outermost layer     * provides passage for small nerves, lymphatic vessels

  ## Arteries

• classified by size   * conducting (elastic or large) arteries     * biggest arteries ( aorta, common corotid, pulmonary trunk,..)   * Distributing (muscular or medium) arteries     * distributes blood to specific organs   * Resistance (small) arteries     * Arterioles: smallest arteries     * control amount of blood to various organs

Aneurysm

Weak point in artery or heart wall

• forms thin- walled, bulging sac and may rupture at any time
• dissecting aneruysm   * blood acculumulates between tunics of artery and separates them.

Atrial sense organ

• sensory structures in walls of major blood vessels that monitor blood pressure and chemistry   * carotid sinuses: baroreceptors monoter blood pressure and found in internal carotid   * carotid bodies: chemoreceptors, stableize pH

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