Blood Components and Functions

• Exam #2 study guide, Crash Courses, Faith's Quizlet cover the following chapters and topics:
  • Chapter 19: Blood
  • Chapter 20: The Heart
  • Chapter 21: Blood Vessels

Functions of Blood

• Blood helps to maintain homeostasis in the body in seven ways:
• Transports gases, nutrients, and waste products (e.g., oxygen)
• Transports processed molecules (e.g., precursor of vitamin D from skin to liver then kidneys)
• Transports regulatory molecules
• Regulates pH and osmosis
  • The normal pH of most body tissues is between 7.35 and 7.45
• Maintains body temperature
  • Warm blood shunted to the interior of the body
• Protects against foreign substances (e.g., antibodies)
• Facilitates clot formation

Components of Blood Plasma

• Blood plasma includes:
• Plasma: The liquid part of blood, making up 55% of its volume
• Plasma is a colloid, meaning it contains suspended substances that don't settle out of solution
• Proteins (7% of plasma):
• Albumins: Contribute to viscosity, osmotic pressure, act as buffers, and transport fatty acids, bilirubin, and thyroid hormones
• Albumins are the most abundant plasma proteins (58%)
• Globulins: Transport lipids, carbohydrates, hormones, ions, antibodies, and complement
• Fibrogen: involved in blood clotting
• Fibrogen is the least abundant plasma protein (4%)
• Water (91% of plasma): Acts as a solvent and suspending medium for blood components
• Electrolytes: Involved in osmosis, membrane potentials, and acid-base balance
• Glucose, amino acids, triglycerides, cholesterol, and vitamins
• Urea, uric acid, creatinine, and ammonia salts
• Products of protein metabolism
• Breakdown product of red blood cells
• End product of anaerobic respiration
• Oxygen, carbon dioxide, and inert nitrogen
• Hormones and enzymes

Formed Elements of Blood

• Red blood cells (erythrocytes):
  • Biconcave discs without a nucleus, containing hemoglobin
  • Transport oxygen and carbon dioxide
  • Most abundant formed element in the blood
  • Have a short lifespan because they lack a nucleus
• White blood cells (leukocytes):
  • Protect the body against microorganisms and remove dead cells and debris
  • Granulocytes: Have large granules in their cytoplasm and multi-lobed nuclei
  • Neutrophils
  • Eosinophils
  • Basophils
  • Agranulocytes: Have small granules in their cytoplasm and nuclei that are not lobed
  • Lymphocytes
  • Monocytes
• Platelets (thrombocytes):
  • Cell fragments
  • Form platelet plugs and release chemicals necessary for blood clotting (coagulation)
  • Carry growth factors

Hemoglobin

• Structure and Function
• Hemoglobin transports oxygen in the blood
• Types
  • Embryonic and fetal: Have a greater affinity for oxygen than adult hemoglobin.
  • Fetal production stops after birth
  • Adult: Primary type in adults
  • Oxyhemoglobin: Transports oxygen
  • Deoxyhemoglobin: Ready to bind oxygen
  • Carbaminohemoglobin: Transports carbon dioxide
• Function
  • Transports oxygen from lungs to tissues (98.5% bound to hemoglobin, 1.5% dissolved in plasma)
  • Transports carbon dioxide from tissues to lungs (7% dissolved in plasma, 23% bound to hemoglobin, 70% as bicarbonate ions)
  • Carbonic Anhydrase is an enzyme found within RBC, facilitates the conversion of CO2 + H2O →↔ H2CO3 → H+ +HCO3-
• Composition:
  • Four globin molecules (polypeptide chains): transport carbon dioxide and nitric oxide
  • NO induces smooth muscles to relax, lowering BP
  • Four heme molecules: transport oxygen which each contain one iron atom
  • Iron is required for oxygen transport, absorbed in the upper small intestine with assistance from stomach acid and vitamin C.
  • Iron is lost in urine, feces, and menstrual fluid

Erythropoiesis

• Erythropoiesis*
• Erythropoietin: Hormone produced mostly by the kidneys, secretion increases when blood oxygen levels are low, stimulates red bone marrow to produce more red blood cells
• Hematopoiesis: process of blood cell production
• Stem cells (hemocytoblast): give rise to all formed elements
• Proerythroblasts: Develop into red blood cells
• Myeloblasts: Develop into basophils, neutrophils, eosinophils
• Lymphoblasts: Develop into lymphocytes
• Monobalsts: Develop into monocytes
• Megakaryoblasts: Develop into platelets
• Red blood cell production requires B12, folic acid, and iron
  • Stem cells > proerythroblasts > early erythroblasts > intermediate erythroblasts > late erythroblasts > reticulocytes
  • Reticulocytes found in higher concentration in male than in female because of testosterone
  • Immature red blood cell that first leaves the bone marrow and enters the bloodstream

Leukocytes

• Neutrophils are the "first line of defense"
  • After leaving bone marrow, stay in circulation for 10-12 hours and then move to other tissues
  • Motile cells that phagocytize bacteria, antigen-antibody complexes, and other foreign matter
  • Contain lysozyme
  • Last 1-2 days
  • Account for 60-70% of WBCs (majority)
• Eosinophils
  • Leave circulation and enter tissues during inflammatory responses and are prevalent in allergic reactions
  • Destroy inflammatory chemicals like histamine
  • Release chemicals to destroy tapeworms, flukes, pinworms, and hookworms
  • Account for 2-4% of WBCs
• Basophils
  • Least common
  • Leave circulation and migrate through tissues
  • Play a role in inflammatory and allergic reactions produce histamine and heparin (blood thinning agent)
  • Account for less than 1% of WBCs
• Lymphocytes
  • Produced in red bone marrow and migrate to lymphatic tissues to proliferate
  • Responsible for antibody production
  • Extensively studied within the immune system
  • Account for 20-25% of the WBCs
• Monocytes
  • Remain in circulation for 3 days, then leave circulation to become macrophages
  • Phagocytic cells that break down antigens and present them to lymphocytes for recognition
  • Account for 3-8% of the WBC

Platelets

• Fragments pinched off from megakaryocytes in red bone marrow
• Glycoproteins and proteins on the surface allow adhesion to other molecules (e.g., collagen)
• Prevent blood loss
  • Forms platelet plugs
  • Promotes formation and contraction of clots
• Hemostasis: Hemostasis stops bleeding through three stages:
  • Vascular spasm: vasoconstriction of damaged blood vessels, caused by thromboxanes from platelets and endothelin from damaged endothelial cells
  • Platelet plug formation
  • Coagulation or blood clotting
  • Two pathways: extrinsic and intrinsic
  • Fibrin fibers (fibrinogen)
  • Requires vitamin K

Blood Groups

• ABO Blood Group System
  • Blood type is determined by antigens (agglutinogens) on the surface of RBCs
  • Antibodies (agglutinins) can bind to RBC antigens, resulting in agglutination (clumping) or hemolysis (rupture) of RBCs
• Rh Blood Group
  • Types:
  • Rh positive: Rh antigens present, no Rh antibodies
  • Rh negative: No Rh antigens present, has Rh antibodies
  • Hemolytic disease of the newborn (HDN):
  • Rh positive fetus, Rh negative mother; late in pregnancy, fetal Rh antigens cross the placenta
  • Mother creates antiRh antibodies (primary response)
  • Subsequent Rh positive pregnancy may initiate secondary response and HDN, where maternal antibodies cross the placenta and destroy fetal RBCs
  • RhoGAM injections contain antibodies against Rh antigens, attaching to and destroying fetal RBCs

Cardiovascular Terms

• PlasmaLiquid part of blood
• Erythropoiesis: RBCs last 120 days in circulation (enucleated)
• RBC life cycle depends on Erythropoiesis
• Proerythroblast: develop into red blood cells
• Megakaryoblast: develops into platelets
• Bilirubin breakdown product of RBCs that is unable to be recycled; waste product
• *Chemotaxis attraction to and movement toward foreign materials or damaged cells (WBCs)
  • Eg. histamine and inflammation
  • Accumulation of dead white cells and bacteria is pus
• Diapedesis cells become thin, elongate and move either between or through endothelial cells of capillaries
• Thrombus a blood clot attached to a blood vessel wall
• Embolus a thrombus which has broken off and is in the bloodstream
• Agglutination: clumping of red blood cells
  • Caused by: a bad transfusion - antibodies, to antigens
• Antigen protein identifiers "flags" if the molecule belongs to the body - calls out to the antibodies.
• Antibody marks foreign antigens for destruction by WBCs
• Reticulocyte: immature RBC first leaves the bone marrow and enters the bloodstream

The Heart

• Apex: The bottom point of the heart
• Base: The top of the heart
• Functions:
  • Generating blood pressure
  • Routing blood, separating into pulmonary and systemic circulations
    • Pulmonary: Through the lungs; right side of the heart
    • Blood entering: deoxygenated
    • Blood exiting: oxygenated
    • Systemic: Through the body; left side of the heart
    • Blood entering: oxygenated
    • Blood exiting: deoxygenated
  • Ensuring one-way blood flow with valves
  • Regulating blood supply according to metabolic rates
• Layers of the Heart Wall:
  • Pericardium: or pericardial sac
  • Fibrous: tough, fibrous outer layer, prevents over distention, acts as anchor
  • Serous: thin, transparent inner layer
  • Parietal Pericardium lines the fibrous outer layer
  • Visceral Pericardium (epicardium) covers heart surface
  • The two are continuous and have a pericardial cavity with pericardial fluid, and prevents friction
  • Heart Wall:
  • Epicardium (visceral pericardium): serous membrane; smooth outer surface of the heart
  • Myocardium middle layer composed of cardiac muscle cell and responsible for heart contracting
  • Endocardium: smooth inner surface of heart chambers
  • Pectinate Muscle muscle ridges in auricles and right atrial wall
  • Trabeculae Carnae muscular ridges and columns on the inside walls of ventricles

Arteries

• Exit aorta just superior to point where aorta exits heart
  • Right Coronary Artery-Lies in the coronary sulcus, Smaller than the left. Extends to posterior aspect of the heart
    • Right Marginal Artery to lateral wall of right ventricle
    • Posterior Interventricular Artery: lies in posterior interventricular sulcus, supplies posterior and inferior aspects of hear
  • Left Coronary Artery- exits aorta near right coronary
    • Branches: -left Anterior Descending Artery: in anterior interventricular sulcus -Left Marginal Artery: supplies lateral wall of left ventricle -Circumflex Artery: extends to posterior aspect

Veins

• Great cardiac vein and small cardiac vein drain right margin of heart
• Coronary sinus: veins empty here then into the right atrium
• Review the structure and functions of the chambers of the heart
  • Atria
  • Right Atrium: Three major opening to receive blood returning from the body
    • Superior vena cava
    • Inferior vena cava
    • Coronary sinus*
  • Interatrial septum wall between the atria, contains a depression, the foramen ovale, a remnant of the fetal opening between the atria
  • Left Atrium: four openings receive blood from the pulmonary veins
• Ventricles
  • From the lungs
  • Right Ventricle: opens to the pulmonary trunk
  • Left Ventricle: opens to aorta
  • Atrioventricular Canals: openings between atria and respective ventricles
  • Interventricular Septum: between the two ventricles

Valves

• Atrioventricular valves (AV valves)-
  • Each valve has leaf-like cusps that are attached to cone-shaped papillary muscle by tendons (chordae tendineae)
    • Right: three cusps (tricuspid)
    • Left: two cusps (bicuspid, mitral)
  • Valve Open- canal is atrioventricular
• Semilunar valve- Right (pulmonary- lungs) and Left (aortic)
  • Each cusp is shaped like a cup
  • When cusps are filled, valve is closed; when cusps are empty, valve is open
• Valve actions during the cardiac cycle
  • Ventricular diastole: AV valves are open allowing blood to flow from atria to ventricles. Semilunar valves are closed.
  • Ventricular systole: AV valves are closed to prevent backflow into atria. Semilunar valves are open, allowing blood ejection into aorta and pulmonary trunk.

Cardiac Cycle

• Period of isovolumetric Contraction (systole) and Ejection (systole)
  • Pressure in the ventricles has increased where it is greater than the pressure in the pulmonary trunk and the aorta.
  • Push cusps of the semilunar valves against the vessels, opening the valve
  • Blood is ejected from the ventricles
• Pressures in the two ventricles are different 120 mm Hg in the left ventricle; 25 mm Hg in the right ventricle.
  • Blood in the left ventricle pumps to whole body
  • Blood in the right ventricles pumps to the lungs
• Period of Isovolumetric Relaxation (diastole)
• Passive Ventricular Filling (diastole)/Active Ventricular filing (diastole)

Cardiac Muscle

• Structural and Functional Characteristics:
  • has a plato phase due to calcium
  • Elongated, branching cells containing 1-2 centrally located nuclei, contains actin and myosin myofilaments
  • Intercalated disks: specialized cell-cell contacts, Cell membranes interdigitate; desmosomes hold cells together, Gap junctions for action potentials cell to cell, connects all the cells together
• Electrically, cardiac muscle of the atria and ventricles behaves as a single unit
• The Conducting System:
  • SA node ("pacemaker of the heart”)-sinoatrial node
    • Medial to opening of superior vena cava/ pacemaker-Specialized cardiac muscle cells generates spontaneous action potentials Action potentials pass to atrial muscle cells and AV node
  • AV node: atrioventricular node
    • Medial to the right atrioventricular valve conducts action potentials slower
      • Ensures ventricles receive signal to contract after atria have contracted
  • AV bundle- passes through hole in cardiac skeleton to reach interventricular septum
  • Right and left bundle branches- extend beneath endocardium to apices of right and left ventricles
  • Purkinje fibers- large diameter cardiac muscle cells with few myofibrils; many gap junctions, conduct action potential to ventricular muscle cells

Electrocardiogram

• Electrocardiogram: records electrical events in the myocardium, correlated mechanical events
  • P wave- depolarization of atrial contraction signifies onset of atrial contraction (muscle contracting)
  • QRS complex ventricular depolarization; signifies ventricular contraction -Atria simultaneously, ventricles contract/ Atria simultaneously
  • T wave- repolarization of ventricles; precedes ventricular relaxation(muscle goes back to relax)
  • PQ interval (PR interval): atria contact and begin to relax/ventricles contract
  • QT interval ventricles contract begin to relax
• Heart Sounds and Significance:
  • First Heart Sound "lubb": *Atrioventricular valves and surrounding fluid vibrations as valves close at beginning or ventricular systole
  • Second heart sound "dubb": *Aortic/and or pulmonary valve or valve closure at beginning of diastole that is longer
  • Third heart sound (occasional): turbulent blood flow into the ventricles, end of heart
  • Ventricular diastole is the last and longest heart sound

Blood Pressue Terms

• Mean arterial pressure average in aorta
  • Blood pressure measurement in arm a reflection of aorta/NOT ventricular pressure
  • MAP = Cardiac Output x Peripheral Resistance
    • CO is amount pumped by heart per minute
    • CO = SV x HR
• **SV: stroke volume (blood beat)
• **HR: * number Heart rate (of beats per minute)
  • Cardiac reserve: diff.rest and maximum
  • PR is total resistance against pumped
  • Affected by pressure, vessels
• Affecting (increase MAP)
  • Decreased , blood PH, Increased CO2, O2, exercise, emotions, heart rate, cardiac output
  • Volume, exercise, and pressure to volume and stroke
  • Decreased Pressure, Decreased PH, Increased Carbon,Decreased
  • vasoconstriction,resistance

Heart Regulation

• Extrinsic Regulation: neural and hormonal control-Parasympathetic "vagal tone" (increases=vagal tone)
• Sympathetic-cardiac (heart rate and force),vessels, atrial, ventricular, Epi increases cardiac output, lower ESV-heart
• SympatheticstimulationadrenalmedullaEpiVessels (vasodilation, volume)
• (Pressure)Increases(blood)volumeElevatesblood decrease/reduce
• (Epi)Vessels:(arterioles)-bloodELEVATEDblood

Temperature regulation

• Hormonal: Epi and Adrenal medulla Response:excitement/stress
• FunctionIncreaseincreaseDecreaseDecrease
• PulmonaryThrough
• SystemicThrough body

Definitions

• Pectinate AtriumMuscular (atrium)
• PapillaryAttach
• TrabeculaeCarnaeVentriclesthink
• ChordaeVentricles
• CoronaryVeins at RIGHT atrium
• Angioplasty -- Expands clot(catheter) -- Intercalated Cellto
• Intercalated

Vessels

• Fiberslarge action to
• completeMuscle -Dicrotic slightly
• monitor-BaroreceptorcarotidsAorta
• Carotidsmedulla oblongota
• Semilunar (aortic) Shaped Each-cup ValveWhen isvalve VALVEisopen
• Systolecontractions Systale, diastolic ,hormonal and
• Diastoletypesregulation-characteristics
• • regulation is normal,neural/hormonal

Chapter 21: Blood Vessels

Types of Vessels

List order:

1. Heart
2. Elastic-Artery
3. Artery
4. Arteriole
5. Metarteriole
6. Capillary
7. Venule
8. Vein
9. Large/Med
10. Veins

Capillaries

• Site of exchange within tissue --Wallthin:endothelial CT

• Scattered are present

  -Substancesmove: -Through Diffusion -TypeContinuousmuscleNervebrain barrier/fenestratedGapsvilli of kidney/Sinusoidallarge gland -Network:Flowsmetarteriolessphincters

Vessels

• Portal: between
• Layers: Layersout -Tunica - Endothelium - Membrane - C.T - Elastica
  • Tunica Muscle
    • Vasoconstriction:decrease
    • increase
  • Tunicavarries CT

Specific Information

• VeinsElasticsmooth elasticity/ stretch
• Arteriesspecific) - Elastic-diameters - MediumVesselsconstricting - SmallVesselsdilation -WallsDiameter -ValveFolds
• Valveslower extremities extremetiesValve
• UnmyelinatedvasoconstrictionSmallbyPara

Other info

• Vascstrictr/detect
• Arteriole:media Pressure
  • VesselselasticEasily Arterio wallsPressure

Vessels

• The major arteries that supply blood include:
  • The common carotid
  • Carotid sinus
  • Internal/External carotid arteries
• List arteries Lt.Subclavian/Axillary/Brachial to include brachiocephalic Subclavian / Axillary / Brachial / ulnar

Blood Information

blood on the wall due to blood •moves due pressure turbulent bypressure

Properties

• Pressure:
• of liquid to flow
• influenced RBC

Other definitions.

• Pressurerates -to - vessel (F=DxP;)Weak bulging out out an
  • Compliance-Compliancedecreases.Pressure rises The radial artery to rate and rhythm is most frequent.

Wall

• Describe across of substance

  -CapillaryExchangeThe out of capillaries: -diffusionexchange :Acrossdiffusing - O2, steroids, -H20 spaces

Affect pressure affect fluid BloodPressure,perm

Capillaries

• Fluid out of capillaries at arterial end
• Fluid into: --chemicals -Edema fluid from

Information

• toneaffec
• The blood pressure-standing Position -hydrostatic

The blood flow.

-regulatingsphincters

hormonal controls

• Nervous Control to to increase --excitory/inhibitory sympathetic --hormones

Test your knowledge of blood components and functions, including red blood cells, hemoglobin, carbon dioxide transport, iron absorption, and plasma proteins. Assess your understanding of blood's role in oxygen transport, temperature regulation, and homeostasis.