232 Lecture 3 exam Flashcards
Describe and understand the functions of blood.
-Transporting dissolved gases, nutrients, hormones and metabolic wastes. Carries O2 to peripheral tissues and carbon dioxide from those tissues back to the lungs. Distributes nutrients. Absorbs wastes produced by tissue cells and carries to kidneys.
-Regulating the pH and Ion composition of interstitial fluids. Such as calcium or potassium. Blood also absorbs and neutralizes acids.
-Restricting fluid losses and injury sites. contains enzymes and other substances that respond to breaks in vessel walls by initiating the clotting process.
-Defending against toxins and pathogens. Blood transports white blood cells and delivers antibodies.
-Stabilizing body temperature. Blood absorbs the heat generated by active skeletal muscles and redistributes it to other tissues.
Describe the major components of plasma
Plasma is plasma protains, other solutes (nutrients, electrolytes, and wastes) and water.
Plasma proteins which are disolved in the plasma is mainly albumins, globulins, and fibrinogen.
Describe the major components in the formed elements
The formed elements of blood are made up of red blood cells, white blood cells and cell fragments known as platelets.
Distinguish between the major plasma proteins (albumins, globulins, fibrinogens)
Albumins - the majority. important for transporting fatty acids, thyroid hormones, and some steroid hormones, and other substances.
Globulins - second most abundant. Examples are antibodies, transport globulins that bind to small ions, hormones, and substances that would other wise be disposed in the urine. Hormone-binding proteins, metalloproteins (transport metal ions), apolipoprotwins, lipoprotein, and steroid-binding proteins.
Fibrinogens - functions in clotting. soluble protein that will be converted to fibrin (insoluble protein).
Know the normal ranges for hematocrit of males and females
The normal hematocrit, or packed cell volume (PCV), in adult males is 46 and in adult females is 42
Describe the structure of RBC’s, and its effects of RBC function
RBC is a biconcave disc with a thin central region and a thicker outer margin. The cytoplasmic surface of an RBC plasma membrane is a meshwork of flexible proteins. The biconcave shape and flexible plasma membrane have three important effects on RBC function:
-Gives each RBC a large surface-area-to-volume ratios. This allows a faster exchange between the RBS’s interior and the surrounding plasma.
-Enables RBCs to form stacks that smooth blood flow through narrow blood vessels. They stack like dinner plates and dissociate repeatedly without affecting the cells involved (aka rouleaux)
-Enables RBCs to bend and flex when entering small capillaries.
Describe and understand the structure of hemoglobin, and its function.
Hemoglobin (Hb) molecule has 2 alpha chains and 2 beta chains of polypetides. Each Hb chain contains a single molecule of heme, a nonprotein pigments complex that forms a ring. Each heme unit holds an iron ion in a way that the iron can interact with an oxygen molecule forming oxyhemoglobin, HbO2, making the red color. Since iron-oxygen interaction is very weak, it can easily dissociate without damaging the heme unit or O2 molecule. When not bound to O2 it is called deoxyhemoglobin.
Once the O2 binds to one Heme the other 3 increase binding probability exponentially.
Know the normal ranges for hemoglobin for males and females
males - 14-18 g/dL
females - 12-16 g/dL
Describe and understand the process of recycling of red blood cell components.
Macrophages of the spleen, liver, and red bone marrow play a central role in recycling red blood cell components.These phagocytes engulf aged red blood cells and also detect and remove Hb molecules from hemolyzed RBCs. Hemoglobin remains intact only inside RBCs. If Hb released by hemolysis is not phagocytized, its components will not be recycled.
Describe and understand the process of erythropoiesis, including regulatory factors
- Erythropoiesis is the formation of RBCs and it occurs throughout life.
- Embryonic blood cells appear in the bloodstream during the third week of development. these cells divide repeatedly, rapidly increasing in number. Blood forms primarily in the vessels of the embryonic yolk sac during the first 8 weeks. As other organ systems appear, some of the embryonic blood cells move out of the bloodstream and into the liver, spleen, thymus and bone marrow. These emryonic cells differentiate into stem cells that divide to produce blood cells. The liver and spleen are the primary sites of hemopoiesis from the second to fifth months. But as the skeleton enlarges, the bone marrow becomes increasingly important.
- In adults erythropoiesis takes place only in red bone marrow (myeloid tissue). this tissue is located in portions of the vertebrae, sternum, ribs, skull, scapulae, pelvis, and proximal limb bones. In extreme situations like blood sustained blood loss yellow marrow can convert to red marrow.
- Regulation: Erythropoiesis is stimulated directly by the hormone erythropoietin (EPO) (and indirectly by other hormones). EPO is produced when external organs, especially the kidneys are exposed to a low concentration of oxygen (hypoxia). 1) during anemia; 2)when blood flow to the kidneys declines; 3) when the oxygen content of air in the lungs declines, due to disease or high altitude; and 4) when the respiratory surfaces of the lungs are damaged.
- EPO travels to the red bone marrow, and stimulates stem cells for RBCs. Two major effects 1) it stimulates cell division rates in erythroblast and in the stem cells that produce erythroblasts, and 2) it speeds up the maturation of RBCs, mainly by accelerating Hb synthesis.
- Stages of RBC Maturation: Hemocytoblasts, or hematopoietic stem cells (HSCs) in the red bone marrow must divide. They produce a myeloid stem cells (turns into RBC and several WBC), or lymphoid stem cells(which produce WBC lymphocytes). RBC go from myeloid stem cells to proerythroblast, to basophilic erythroblast, to polychromatophilic erythroblast, to a normoblast (ejects it nucleus), then enters the blood stream as a reticulocyte where it matures to a RBC.
Describe and understand the ABO blood types and their importance.
Blood type is determined by the presence or absence of specific surface antigens in RBC plasma membranes. The surface antigens involved are integral membrane glycoproteins whose characteristics are genetically determined. They can have up to 50 surface antigens but ones with particular importance is A, B, and Rh (or D).
Type A has RBCs with surface antigen A only, Type B has surface antigen B only, and Type AB has both A and B, while Type O has neither A nor B. Rh blood group is based on the presence or absence of Rh surface antigen (positive means there is an antigen, and negative means there isn’t an antigen). Type A also has anti-B antibodies, while Type B has anti-A antibodies, Type AB has neither, and Type O has both anti-A and B antibodies. This is important to insure that a person doesn’t reject the blood when there is a transfusion. You would need to insure you give the correct blood to the correct recipient.
Blood transfusion: Focus on Donor Antigens and Recipients Antibodies.
Differentiate between the structure and function of the 5 types of white blood cells.
- Never Let Monkeys Eat Banana’s
- Neurtophils - Structure: round cell; nucleus lobed and may resemble a string of beads; cytoplasm contains large, pale inclusions. Functions: Phagocytic: engulf pathogens or debris in tissues, release cytotoxic enzymes and chemicals.
- Lymphocytes - Structure: generally round cell, slightly larger than RBC; round nucleus; very little cytoplasm. Function: cells of lymphatic system, providing defense against specific pathogens or toxins.
- Monocytes - Structure: Very large cell; kidney bean-shaped nucleus; abundant pale cytoplasm. Function: Enter tissues to become macrophages; engulf pathogens or debris.
- Eosinophils - Structure: round cell; nucleus generally in two lobes; cystomplasm contains large granules that generally stain bright red. Function: Phagocytic: Enfulf antibody labeled materials, release cytotoxic enzymes, reduce inflammation; increase in allergic and parasitic situations.
- Basophils - Structure: Round cell; nucleus generally cannot seen through dense, blue-stained granules in cytoplasm. Function: Enter damaged tissues and release histamine and other chemicals that promote inflammation.
Describe and understand the origins and differentiation of all the formed elements.
Hemocytoblast divisions give rise to myeloid stem cells or lymphoid stem cells. Myeloid stem cells produce progenitor cells that divide to produce red blood cells, platelets, and white blood cells expept for lymphocytes. The targets of erythropoietin (EPO) and the four colony-stimulating factors (CSFs) are indicated. Lymphoid stem cells produce the various lymphocytes.
Describe the structure, function, and production of platelets.
Platelets are disc-shaped cell fragments. Play a major role in vascular clotting system.
Function: (1)Releasing chemicals important to the clotting process. (2) Forming a temporary patch in the walls of damaged blood vessels. (3) Reducing the size of a break in a vessel wall.
Production: AKA thrombocytopoiesis. Takes place in the red bone marrow. Megakaryocytes, enormous cells with a large nuclei, manufacture sturctural proteins, enzymes and membranes. They then begin shedding cytoplasm in small membrane-enclosed packets. These packets are the platelets that enter the bloodstream. One megakaryocyte can produce about 4,000 platelets before the end of its life when phagocytes engulf its nucleus for breakdown and recycling.
Discuss and understand the process of hemostasis
- Hemostasis is the stopping of bleeding, which stops the loss of blood through the walls of damaged vessels.
- The Vascular Phase: The vascular phase of hemostasis lasts for about 30 minutes after the injury occurs. The endothelial cells contract and release endothelins, which stimulate smooth muscle contraction and endothelial division. The endothelial cells become “sticky” and adhere to platelets and each other.
- The Platelet Phase: The platelet phase of homeostasis begins with the attachment of platelets to sticky endothelial surfaces, to the basement membrane, to exposed collagen fibers, and to each other. As they become activated, platelets release a variety of chemicals that promote aggregation, vascular spasm, clotting and vessel repair.
- The Coagulation Phase: Bloody clotting involves a comples sequence of steps leading to the conversion of circulating fibrinogen (a soluble protein) into fibrin (an insoluble protein). As the fibrin network grows, blood cells and additional platelets are trapped in the fibrous tangle, forming a blood clot that seals off the damaged portion of the vessels. (Extrinsic pathway, Intrinsic pathway and Common pathway).
- Clot Retraction: Once the firbrin meshwork has formed platelets and red blood cells stick to the fibrin strands. the platelets then contract, and the entire clot begins to undergo clot retraction, a process that continues over 30-60 minutes.
Explain Coagulation phase
Extrinsic pathway and intrinsic pathway create an activator complex that activates Factor X. Factor X turns into Prothrombin activator. The Prothrombin activator combines with Prothrombin to create Thrombin. The Thrombin combines with Fibrinogen to create Fibrin.
Outline the general paths of systemic, pulmonary, and coronary circulation.
Pulmonary circuit - carries blood to and from the lungs
Systemic circuit - transports blood to and from the rest of the body.
Coronary circulation - meets the high oxygen and nutrient demands of the cardiac muscle cells. The coronary arteries originate at the base of the ascending aorta. Interconnections between arteries, called arterial anastomoses, ensure a constant blood supply. The great, posterior, small, anterior, and middle cardiac veins are epicardial vessels that carry blood from the coronary capillaries to the coronary sinus.
Describe the location of the heart and its surface features.
The heart is located in the thoracic cavity near the anterior chest wall, directly posterior to the sternum. The great vessels, both veins and arteries, are connected to the superior end of the heart at its base. The base sits posterior to the sternum at the level of the third costal cartilage, centered about 1.2cm to the left side. Standard measurements for determining heart size take into account age, height, weight, and sex. Midsagittal doesn’t divid it into equal parts. The center of the base lies slightly to the left of the midline. Sits in the anterior portion of the mediastinum, the region between the two pleural cavities.
Describe the structural organization of the pericardium, and its function.
The pericardium surrounds the heart and consists of an outer fibrous pericardium and an inner serous pericardium. The fibrous pericardium contains a dense network of collagen fibers that stabilize the position of the heart and associated vessels within the mediastinum. The inner serous pericardium is a two-layered membrane (outer-parietal layer; inner-visceral layer or epicardium). The potential, fluid-filled space between these two serous layers is pericardial cavity filled with pericardial fluid (about 15-50mL). This acts as a lubricant, reducing friction between the opposing visceral and parietal surfaces as the heart beats.
Identify the layers of the heart wall
Identify the internal structures of the heart
Identify and describe the components of the, conduction system
The components of the cardiac conduction system include the SA node, the AV node, the AV bundle, the AV bundle branches, and the Purkinje cells.
The Sinoatrial (SA) node is embedded in the posterior wall of the right atrium, near the entrance of the superior vena cava. The primary dirver of the heart rate, aka cardiac pacemaker.
The relatively large atrioventricular (AV) node is located at the junction between the atria and ventricles, near the opening of the coronary sinus. The pacemaker cells of this node send on signals from the cells of the SA node, and act as a backup to the SA node pacemaker cells.
In the atria, conducting cells are found in internodal pathways in the atrial walls. These pathways distribute the contractile stimulus to atrial muscle cells as this electrical impulse travels from the SA node to the AV node.
In the ventricles, conducting cells include those in the atrioventricular (AV) bundle and the bundle branches that run between the ventricles, as well as the Purkinje fibers, which distribute the stimulus to the ventricular myocardium.
Describe and understand impulse conduction through the heart
Identify the major features on an ECG, and describe what they represent
Describe and understand the steps in an action potential of a cardiac contractile cell.
Describe and understand the phases of the cardiac cycle (fig 20-16)
The phases of the cardiac cycle-atrial systole, atrial diastole, ventricular systole, and ventricular diastole. When the cardiac cycle begins all four chambers are relaxed, and the ventricles are partially filled with blood. During atrial systole the atria contract, filling the ventricles completely with blood. Atrial systole lasts 100 msec. The atria next enter atrial diastole, which continues until the start of the next cardiac cycle. Ventricular systole (lasts 270 msec) begins at the same time as atrial diastole. The ventricles push blood through the systemic and pulmonary circuits and toward the atria. The heart then enters ventricular diastole, which lasts 530 msec.
Describe and understand the pressure and volume relationships in the cardiac cycle (fig. 20-17)
1) Atrial contraction begins.
2) Atria eject blood into the ventricles.
3)Atrial systole ends; Av valves close.
4) Isovolumetric ventricular contraction occurs.
5) Ventricular ejection occurs.
6) Semilunar valves close.
7) Isovolumetric relaxation occurs.
8) AV valves open; passive ventricular filling occurs.
Know what causes the “lub”, “dub” of heart sounds
There are four heart sounds, named S1 through S4. The first heart sound (S1) known as the “lubb”, is start of ventricular contraction when the AV valves close and the semilunar valves open. S2 occurs at the beginning of ventricular filling, when the semilunar valves close and the AV valves open. The third and fourth heart sounds are usually very faint and are seldom audible in healthy adults. S3 is the blood flowing into the ventricles and S4 is the atrial contraction.
Define cardiac output and describe the factors that influence this variable.
Cardiac output (CO) is the amount of blood pumped by the left ventricle in 1 minute. Cardiac output can be adjusted by changes in either heart rate or stroke volume. The heart rate (HR), the number of heartbeats per minute, can be adjusted by the activities of the autonomic nervous system or by circulating hormones. Stroke volume (SV) is the amount of blood pumped out of a ventricle during each contraction.
Describe the factors that influence stroke volume
EDV and ESV
- EDV - (End-Diastolic Volume) two factors affect this; the amount of blood in the ventricle at the end of diastole: Filling time and the venous return.
1. venous return - amount of blood returning to the heart through veins. (variable on heart rate.)
2. filling time - the duration of ventricular diastole. (Depends on HR; faster=shorter filling time)
3. preload - the degree of stretching in ventricular muscle cells during ventricular diastole. Directly proportional to the EDV. ^EDV=^preload. - ESV - End-Systolic volume
1. ANS -
2. hormones - E, NE and T3 are positively inotropic (increase HR). Some drugs treat hypertension are negatively inotropic (decrease HR).
3. contractility - the amount of fouce produced during a contration, at a given preload.
4. vasodilation/vasoconstriction - Vasodilation alters hemodynamics in such a way as to increase stroke volume. vasoconstriction reduces the stroke volume
5. afterload - how much pressure is needed to open the semilunar valves.
Describe the general structure of vessel walls
- tunica intima is the inner layer of the vessel
- Tunica media is the middle layer of the blood vessel. Contains sheets of smooth muscle tissue in a framework of loose connective tissue.
- Tunica externa or tunica adventitia, is the outer layer of a blood vessel.it is a connective tissue sheath. in arteries, it contains collagen fibers with scattered bands of elastic fibers. In veins, it is generally thicker than the tunica media and contains networks of elastic fibers and bundles of smooth muscle cells.
Distinguish between the types of blood vessels based on structure and function
- Arteries
1. elastic arteries - the walls are not very thick realative to the external vessel diameter, but they are extremely resilient. The tunica media of these vessels contains relatively few smooth muscle fibers and high density of elastic fibers. Elastic rebound occurs to some degree in all elastic arteries.Pressure rises rapidly during ventricular systole and the elastic arteries expand as the stroke volume is ejected.
2. muscular arteries - or medium-sized arteries, have a thicker tunica medica with a greater percentage of smooth muscle fibers that elastic arteries.
3. arterioles - considerably smaller than muscular arteries. They have a poorly defined tunica externa, and their tunica media consists of scattered smooth muscle fibers that may not form a complete layer. They change in their luminal diameter that affect the amount of force required to push blood around. - Capillaries
1. continuous capillaries - Continuous capillaries have an endothelium that completely surrounds the lumen. Tight junctions and desmosomes connect the endothelial cells. Permit water, small solutes, and lipid-soluble substances to diffuse into the interstitial fluid. At the same time they prevent the loss of blood cells and plasma protains.Bulk transport by means of endocytosis or exocytosis at the inner endothelieal surface.
2. fenestrated capillaries - contain “windows,” or pores in their walls, due to an incomplete or perforated endothelial lining. This allows for rapid exchange of water and solutes between blood and interstitial fluid. - Capillary beds - Interconnected collective network of capillaries.
- Veins
1. venules - collect blood from capillaries. Thy resembel expanded capillaries, and lack a tunica media.
2. medium-sized veins - correspond in general size to medium-sized arteries. in these veins, the tunica media is thin, and it contains relatively few smooth muscle fibers.
3. large veins - include the superior and inferior venae cavae and their branches within the abdominopelvic and thoracic cavities.they have a thin tunica media and large lumen.
Describe the factors that affect total peripheral resistance
Peripheral resistance is the resistance of the entire cardiovascular system.The total peripheral resistance of the cardiovascular system reflects a combination of: vascular resistance, blood viscosity, and turbulence.
* vascular resistance - is the forces that oppose blood flow in the blood vessels. The most important factor is friction between blood and the vessel walls. The amount of friction depends on two factors: vessel length and internal vessel diameter.
* blood viscosity - is the resistance to flow caused by interactions among molecules and suspended materials in a liquid.
* turbulence - high flow rates, irregular surfaces, and sudden changes in vessel luminal diameter upset the smooth flow of blood, creating eddies and swirls (known as turbulence). which increases resistance and slows blood flow.
Describe how diffusion, filtration, and reabsorption play a role in exchange in capillaries
- diffusion - tends to eliminate the concentration gradient. It occurs most rapidly when 1) the distance involved are short, 2) the concentration gradient is steep, and 3) the ions or molecules involved are small.
- filtration - the removal of solutes as a solution flows across a porous membrane. Solutes too large to pass through the pores are filtered out of the solution. Driven by hydrostatic pressure.
- reabsorption - occurs as a result of osmosis. the osmotic pressure (OP) of a solution represents the pressure that must be applied to prevent osmotic movement across a membrane.
Identify the forces acting across capillary walls.
At the arterial end of a capillary, capillary hydrostatic pressure (CHP) is greater than blood colloid osmotic pressure (BCOP), so fluid moves out of the capillary (filtration). Near the venule, CHP is lower than BCOP, so fluid moves into the capillary (reabsorption).
Describe and understand the three mechanisms of cardiovascular regulation
-Autoregulation
-Neural mechanisms
-Hormones
- Autoregulation - under normal resting conditions, cardiac output remains stable, and peripheral reistance whitin individual tissues is adjusted to control local blood flow. Vasomotion is controlled locally by changes in the concentration of chemical and disolved gases in the interstitial fluids.
- Neural mechanisms - the nervous system adjusts cardiac output and perpheral resistance to maintain adequate blood flow to vital tissues and organs. The center primarily responsible for these regulatory activities is the cardiovascular (CV) center of the medulla oblongata. Using E and NE directly from the medulla oblongata to the heart and vessels to either decrease/increase HR or vasodilation/vasoconstriction respectively.
- Hormones - endocrine system regulates cardiovascular performance in both the short trem and the long term. ADH, angiotensin II, EPO, and ANP and BNP. ADH stimulates water conservations in the kidneys reducing blood pressure. Angiotensin II stimulates aldosterone causing Na+ reabsorption and K+ loss. Stimulates the secretion of ADH, completing the effects of aldosterone. Stimulates thirst, increasing blood volume. Stimulates CO and constriction of arterioles, increasing systemic blood pressure.
Explain how the cardiovascular system responds to various demands on exercise and hemorrhaging
- exercise - The skeletal muscle and the heart get priority while rest of the body (except the brain) reduce blood distribution. The brain stays the same no matter what. While during rest and digest the kidneys and abdominal viscera get priority.
- hemorrhaging -
Understand the anatomy and importance of the hepatic portal circulation
Begins in the capillaries of the digestive organs and ends in the liver sinusoids. It contains substances absorbed from the stomach and intestines. The Hepatic portal system delivers things like glucose and amino acids directly to the liver for storage, metabolic conversion or excretion.
Understand the importance of the cerebral arterial circle to brain function
It is a fail safe incase there is a blockage that blood can still be delived to parts of the brain by going around.
Understand fetal circulation
The fetal circulation is basically bacwards with the oxygenated vs deoxygenated. The umbilical vein is oxygenated bringing blood from the placenta to the babies liver then to heart with an opening in the foramen ovale and ductus arteriosus. down the aorta to the umbilical arteries to be reoxygenated in the placenta.
