Chapter 13
3.) Distinguish between the different formed elements of the blood
1.) Erythrocytes (red blood cells, RBC) -flattened, bioconcave disc, which allow it to fit in capillaries. -carry oxygen -lack nuclei and mitochondria -only last 120 days -each contain hemoglobin molecules, which give blood its red color, and it consists of four protein chains called globins. 2.) Leukocytes (white blood cells) -have a nuclei and mitochondria -move in amoeboid fashion -Diapedsis-movement through the capillary wall into connective tissue. Type of Leukocytes 1.) Granular leukocytes: neutrophils, eosinophils (looks red), basophils (looks blue) 2.) Agranular leukocytes: lymphocytes, and monocytes.
12.) Compare the structures and function of arteries and veins, and the significance of the skeletal muscle pumps.
Arteries contain three layers, or tunics: the interna, media and externa. Moves blood away from the heart. 1.Large arteries, containing many layers of elastin, can expand and recoil with rising and falling blood pressure. 2. Medium and small arteries and arterioles are less distensible and thus provide greater resistance to blood flow. Veins have the same three tunics as arteries but they generally have a thinner muscular layer than comparably sized arteries. Moves blood towards the heart.. 1.) veins are more distensible than arteries and can expand to hold a larger quantity of blood 2.) Many veins have venous valves that ensure a one-way flow of blood to the heart. 3.) the flow of blood back to the heart is aided by contraction of the skeletal muscles that surround veins. The effect of this action is called the skeletal muscle pump.
2.) Describe the relationship between interstitial fluid, plasma, and lymph.
As blood plasma (fluid portion of the blood) passes through capillaries, the hydrostatic pressure of the blood forces some of this fluid out of the capillary walls. Fluid derived from plasma that passes out of capillary walls into the surround tissues is called tissue fluid., or interstitial fluid. Some of this fluid returns directly to capillaries, and some enters into Lympathic vessels located in the connective tissue around the blood vessels. Fluid in lympathic vessels is called lymph. This fluid is returned to the venous blood at specific sites. LOOK for the picture
14.) Explain the causes and dangers of atherosclerosis.
Atherosclerosis is the most common form of arteriosclerosis (hardening of the arteries) and through its contribution to heart disease and stroke. Plaques, protude into the lumen of the artery and thus reduce blood flow. It is currently believed that the process of atherosclerosis begins as a result of damage or insult, such as high blood cholesterol, smoking, hypertension, etc.
13.) Describe the structure and functions of different types of capillaries
Continuous capillaries are those in which adjacent endothelial cells are closely joined together. Found in CNS, muscles, lungs, adipose tissue. The lack of intercellular channels in continuous capillaries in the CNS contributes to the blood-brain barrier. Continuous capillaries in other organs have narrow intercellular channels that permit the passage of molecules other than protein between the capillary blood and tissue fluid. Fenestrated capillaries occur in the kidneys, endocrine gland, and intestines. Covered by a layer of mucoprotein, which serves as a basement membrane over the capillary endothelium. This mucoprotein layer restrict the passage of certain molecules that might other wise be able to pass through the large capillary pores. Discontinuous capillaries are found in the bone marrow, liver and spleen.
1.) Identify the functions and components of the circulatory system
Functions- "Transportation"; All substances essential for cellular metabolism are transported by the circulatory system. Which are; a. Respiratory; Red blood cells, or erythrocytes, transport oxygen to the cells. b. Nutritive; the digestive is responsible for the mechanical and chemical breakdown of food so that it can be absorbed through the intestinal wall into the blood lymphatic vessels c. Excretory; metabolic wastes, excess water and ions. (SHIIIIT THE BODY DONT NEED) 2.) "Regulation"; both hormonal and temperature regulation a. Hormonal; blood carrier hormone from site of origin to target tissue. b. Temperature; aided by the diversion of blood from deeper to more superficial cutaneous vessels or vice versa. 3.) "Protection"- against blood lost, pathogens, toxins, etc. a. Clotting. The clotting mechanism protects against blood loss when vessels are damaged. b. Immune. The immune function of blood is performed by the leukocytes (white blood cells) that protect against pathogens. The major components are 1.) Cardiovascular system- consist of heart and blood vessels 2.) Lymphatic system- consist of lymphatic vessels and lymphoid tissues within the spleen, thymus, tonsils, and lymph nodes.
10.) Describe the pacemaker potential and the myocardial action potential, and explain how the latter correlates with myocardial contraction and relaxation
In a normal heart, the sinoatrial node (SA node), functions as the pacemaker. The cells of the SA node do not maintain a resting membrane potential in the manner of resting neurons or skeletal muscles. Instead, during the period of diastole, the SA node exhibits a slow spontaneous depolarization called pacemaker potential. Because this pacemaker potential occurs during diastole, it is also called a diastolic depolarization. Spontaneous depolarization and automatic heartbeat, involves ion channels in the plasma membrane such as HCH channels, and in the sacroplasmic reticulum. Action potentials are conducted by myocardial cells in the atria and are transmitter to the ventricles by specialized conducting tissue. Once another myocardial cell has been stimulated by action potentials originating in the SA node, it produces its own action potential. When stimulated by action potentials from a pacemaker region, these cells become depolarized to threshold, at which point their voltage regulated Na+ gates open. Action potentials that originated in the SA node spread to adjacent myocardial cells of the right and left atria through the gap junctions between the cells. The impulses cannot be conducted directly from the atria to the ventricles. Therefore, specialized conducting tissue composed of myocardial cells is required. They are AV node, bundle of His, and Pukinje fibers.
15.) explain the cause and significance of angina pectoris.
Myocardial ischemia is associated with increased concentrations of blood lactic acid produced by anaerobic metabolism in the ischemic tissue. This condition is often causes substernal pain, which may also be referred to the left shoulder and arm, as well as to other areas. This referred pain is called angina pectoris
11.) Describe the components of the ECG and their relationships to the cardiac cycle.
Potential difference generated by the heart are conducted to the body surface, where they can be recorded by surface electrodes placed on the skin. The recording thus obtained is called an "electrocardiogram". (not recording of action potential). Each cardiac cycle produces three distinct ECG waves, designated P, QRS, and T. The spread of atrial depolarization thereby creates P waves. The spread of the depolarization into the ventricles is thereby represented by the QRS wave. The plateau phase of the cardiac action potential is related to the S-T segment of the ECG. Finally, repolarization of the ventricles produces the T wave.
4.) Describe the regulation of red and white blood cell production.
Regulation of Leukopoiesis - a variety of cytokines stimulate different stages of leukocyte development. Granulocyte colony-stimulating factor (G-CSF) acts in a highly specific manner to stimulate the development of neutrophils, whereas granulocyte-monocyte colony-stimulating factor (GM-CSF) stimulates the developement of monocytes and esinophils. Regulation of Erythropoiesis -The primary regulator of erythropoiesis is erythropoietin, produced by kidneys in response to tissue hypoxia when the blood oxygen levels are decreased. The stimulation of erythropoesis, has a daily production of new red blood cells, which makes up for the ones that has been destroyed.
8.) Describe the cardiac cycle in terms of systole and diastole of the atria and ventricles
The cardiac cycle refers to the repeating pattern of contraction and relaxation of the heart. The phase of contraction is called systole, and the phase of relaxation is called diastole. There is an atrial systole and diastole. Atrial contraction occurs toward the end of diastole, when the ventricles are relaxed; when the ventricles contract during systole, the atria are relaxed. The heart thus has a two-step pumping action. The right and left atria contract almost simultaneously. 1.) During diastole, first the atria and then ventricles fill with blood. 2.) The ventricles are about 80% filled before the atria contract and add the final 20% to the end-diastolic volume. 3.) contraction of the ventricles ejects about two-thirds of their blood, leaving about one-third as the end-systolic volume.
7.) Describe the structure of the heart and its components
The heart contains four chambers; two atria, which receive venous blood, and two ventricles, which eject blood into arteries. *The right ventricle pumps blood to the lungs, where the blood becomes oxygenated; the left ventricle pumps oxygenated blood to the entire body.*
6.) Distinguish between the systemic and the pulmonary circulation
The path of blood from the heart (right ventricle), through the lungs, and back to the heart (left atrium) completes one circuit: the pulmonary circulation. Oxygen-rich blood in the left atrium enters the left ventricle and is pumped into a very large, elastic artery-the aorta. The aorta ascends for a short distance, makes a U-turn and then descends through the thoracic (Chest) and abdominal cavities. Arterial branches from the aorta supply oxygen-rich blood to all of the organ system and are part of the systemic circulation.
5.) Explain blood typing and blood clotting
There are several groups of red blood cell antigens, but the major group is known as the ABO system. In terms of the antigens present on the red blood cell surface, a person may be type A (with only A antigens), type B (with only B antigens), type AB (with both A and B antigens), or type O (with neither A or B). Antigens are found on the surface of cells to help immune recognize self cells. Antibodies, secreted by lymphocytes in response to foreign cells. Another group of antigens are found on the red blood cells of most people is Rh Factor. Antigen D. Rh-positive has the antigen,. Rh negative does not have the antigen; will not have antibodies unless exposed to Rh+ either through a blood transfusion or pregnancy. Blood clotting 1.) When a blood vessel is injured, a mechanism is activated that promotes hemostasis, or the cessation of bleeding. 2.) Damage exposes collagen fibers to blood producing a. vasocontriction b. formation of platelet plugs b. formation of fibrin protein web.
9.) Explain how the pressure differences within the heart chambers are responsible for blood flow during the cardiac cycle
When the ventricles contract at systole, the pressure within them first rises sufficiently to close the AV valves and then rises sufficiently to open the semilunar valves. 1.) blood is ejected from the ventricles until the pressure within them falls below the pressure in the arteries. At this point, the semilunar valves close and the ventricles begin relaxation. 2.) when the pressure in the ventricles falls below the pressure in the atria, a phase of rapid filling of the ventricles occur, followed by the final filling cause by contraction of the atria.
