Chapter 12 : Circulatory System Flashcards

Question

What causes blood to move from the atria to the ventricles?

Answer 1

Atrial contraction

Answer 2

Made up of: Heart: Central pump Blood vessels: Move blood through body Blood: Transport medium

Answer 3

- Muscular pump - Provides the force necessary to circulate blood to all tissues in body -- Tissues need a continuous supply of oxygen and nutrients -- Metabolic waste products must be removed - Pumps five liters of blood every minute

Answer 4

Located in thoracic cavity between the lungs - Posterior to sternum - Anterior to vertebral column Two thirds of heart mass is to the left of body’s midline (one third is to the right) Apex: Pointed end of heart -- Extends downward to level of fifth intercostal space Base: Opposite end -- Larger and less pointed than apex -- Has several large vessels attached to it Size of heart varies with size of individual -- Average is 9 cm wide and 12 cm long (size of a closed fist)

Answer 5

Loose-fitting, double-layered sac that encloses the heart consisting of: - Fibrous pericardium: Outer layer of pericardium -- Consists of tough, white fibrous connective tissue - Parietal pericardium: Serous membrane that lines the fibrous pericardium - Visceral pericardium: Parietal pericardium reflects back onto the surface of the heart to form the visceral pericardium * Also called epicardium

Answer 6

Small space between parietal and visceral layers of pericardium - Contains a thin layer of serous fluid * Reduces friction between the membranes as they rub against each other during heart contractions

Answer 7

(same as the visceral pericardium) consists of a serous membrane - Thin protective layer, firmly anchored to underlying muscle - Contains blood vessels that nourish heart wall

Answer 8

Composed of cardiac muscle tissue. Contraction of myocardium provides force that ejects blood from heart and moves it through vessels - Endocardium: Smooth inner lining of heart wall * Permits blood to move easily through heart * Forms the valves of the heart

Answer 9

Thin-walled chambers - Receive blood from the veins

Answer 10

Thick-walled chambers - Forcefully pump blood out of the heart

Answer 11

Receives deoxygenated blood from superior vena cava and inferior vena cava - Superior vena cava: Returns blood to heart - Inferior vena cava: Returns blood to heart

Answer 12

Receives oxygenated blood from lungs through four pulmonary veins

Answer 13

Partition that separates right and left atria Fossa ovalis: Thin region in the septum, represents an opening (foramen ovale) that is present between the atria in the fetal heart

Answer 14

Receives blood from the right atrium - Pumps it to lungs, where it picks up oxygen

Answer 15

Receives blood from left atrium - Pumps it to tissues of body

Answer 16

Thick, muscular partition between the right and left ventricles

Answer 17

1. Superior vena/ Inferior vena cava 2. Right atrium 3. Tricuspid (AV) valve 4. Right ventricle 5. Pulmonary artery 6. Pulmonary veins 7. Left atrium 8. Mitral (AV) valve 9. Left ventricle 10. Aorta (arch)

Answer 18

- Permit the flow of blood from atria into corresponding ventricle - Prevent backflow of blood from ventricles into atria - Consist of a fibrous connective tissue ring and double folds of endocardium * Form the cusps of the valve – attached to papillary muscles in the ventricles by chordae tendineae Tricuspid valve: Between right atrium and right ventricle * Has three cusps Bicuspid (mitral) valve: Between left atrium and left ventricle * Has two cusps

Answer 19

- Located at the bases of the large vessels that carry blood from the ventricles - Each valve consists of three cuplike cusps - Prevent the flow of blood back into the ventricles - Pulmonary SL valve: Located at the exit of the right ventricle in the base of the pulmonary trunk - Aortic SL valve: Located at the exit of the left ventricle in the base of the aorta

Answer 20

Both atria contract at the same time. Both ventricles contract at the same time. Heart functions as two pumps - Pulmonary circulation: Pump on the right side * Pumps blood to lungs - Systemic circulation: Pump on the left side * Pumps blood to rest of body - Blood enters right atrium through superior vena cava and inferior vena cava * Low in oxygen and high in carbon dioxide - Flows through tricuspid valve into right ventricle - Passes through pulmonary SL valve - Flows into pulmonary trunk and into pulmonary arteries - Blood carried to lungs - Carbon dioxide is released and oxygen is picked up - Pulmonary veins carry blood to left atrium - Blood flows through bicuspid valve into left ventricle - Flows through aortic SL valve into aorta - Distributed to all parts of the body through the systemic circulation

Answer 21

Myocardium - Needs a continuous supply of oxygen and nutrients - Has an extensive network of blood vessels Two coronary arteries branch from aorta - Right and left coronary arteries have numerous branches Functions - Pump blood to the lungs through the pulmonary circulation - Pump blood to the rest of the body through the systemic circulation - Accomplished by contraction and relaxation of the cardiac muscle in the myocardium

Answer 22

- Located in the right atrium, near entrance of superior vena cava - Initiates impulses without neural stimulation * 70-80 times per minute - Establishes basic rhythm of the heartbeat * Called the pacemaker of the heart - Impulses travel throughout atrial myocardium * Cause atria to contract simultaneously * Impulses reach AV node

Answer 23

Located in floor of right atrium, near interatrial septum - Cells in the AV node conduct impulses more slowly * Causes brief delay as impulses travel through the node Atrioventricular bundle, bundle branches, and conduction myofibers - From AV node, impulses travel through AV bundle (bundle of His) to right and left bundle branches - Bundle branches * Extend along the right and left sides of the interventricular septum * Branch profusely to form conduction myofibers (Purkinje fibers) - Conduction myofibers transmit impulses to myocardium * Cause ventricles to contract simultaneously—blood is forced out through SL valves into aorta

Answer 24

Consists of one heartbeat - Two atria contract at same time - Then relax while two ventricles contract With a heart rate of 75 beats per minute, one cardiac cycle lasts 0.8 second - Atrial systole: Contraction of the atria (0.1 second) * AV valves are open * Ventricles are in diastole (relaxed) * Blood is forced into ventricles - Ventricular systole: Contraction of ventricles (0.3 second) * Atria are in diastole (relaxed)—filling with blood returned through venae cavae All chambers are in simultaneous diastole (0.4 second) * 70% of ventricular filling occurs during this period

Answer 25

First heart sound: Lubb - Caused by closure of AV valves Second heart sound: Dupp - Caused by closure of SL valves Pause between dupp of the first beat and lubb of second beat - Entire heart is resting Abnormal heart sounds: Murmurs - Caused by faulty valves

Answer 26

Primary transport medium - Provides cells with nutrients and oxygen - Removes metabolic wastes Connective tissue Consists of cells and cell fragments (formed elements) suspended in an intercellular matrix (plasma) Blood is the only liquid tissue in the body Blood volume in an average adult - Female: 4-5 liters - Male: 5-6 liters Functions - Transportation - Regulation - Protection Transportation - Carries oxygen and nutrients to cells - Transports carbon dioxide and nitrogenous wastes from the tissues to the lungs and kidneys - Carries hormones from endocrine glands to target tissues Regulation - Regulates body temperature * Removes heat from skeletal muscles: - Fluid and electrolyte balance * Salts and plasma proteins contribute to the osmotic pressure - pH regulation through the action of buffers in the blood Protection - Clotting mechanisms prevent fluid loss through hemorrhage when blood vessels are damaged - Phagocytic white blood cells help protect against microorganisms - Antibodies in the plasma help protect against disease

Answer 27

Plasma: 55% of blood volume Red blood cells: 45% of blood volume Buffy coat - Consists of WBCs and platelets - Forms a thin white layer between the plasma and RBCs

Answer 28

Liquid portion of the blood - 90% water - Remaining portion is approximately 100 different organic and inorganic solutes

Answer 29

Most abundant solute Remain in blood and interstitial fluid - Are not used for energy Many are synthesized in liver Types - Albumins - Globulins Fibrinogen

Answer 30

60% of plasma proteins Produced in liver Contribute to osmotic pressure of blood Play role in maintaining fluid balance between blood and interstitial fluid Play role in maintaining fluid balance between blood and interstitial fluid * If the osmotic pressure of blood decreases, fluid moves from blood into interstitial spaces * If blood osmotic pressure increases, fluid moves from interstitial spaces into blood

Answer 31

36% of the plasma proteins Three types * Alpha and beta globulins: Produced in the liver * Gamma globulins: Produced in lymphoid tissue

Answer 32

4% of plasma proteins Produced in liver Functions in blood clotting * During clotting process, soluble fibrinogen is converted into insoluble fibrin * When blood clots in a test tube, liquid that remains is called serum

Answer 33

Urea and uric acid: Waste products of protein and nucleic acid catabolism - Transported to the kidneys for excretion Respiratory gases - Oxygen and carbon dioxide Electrolytes - Important in: * Muscle contraction * Nerve impulse conduction * pH of body fluids

Answer 34

Erythrocytes: Red blood cells (RBCs) Leukocytes: White blood cells (WBCs) Thrombocytes: Platelets

Answer 35

Production of blood cells - Before birth * Occurs primarily in liver and spleen - After birth * Red bone marrow in specific regions of body * Some WBCs are produced in lymphoid tissue - Hemocytoblast: a stem cell in the bone marrow from which blood cells develop * Seven different cell lines develop from the hemocytoblast

Answer 36

Characteristics and functions of RBCs - Most numerous of formed elements - RBC range for adult * Female: 4-5.5 million RBCs/cubic millimeter (mm3) of blood * Male: 4.5-6.2 million RBCs/cubic millimeter (mm3) of blood Biconcave disks: Thin in middle and thicker around periphery * Provide flexibility for moving through capillaries * Provide maximum surface area for diffusion of gases Mature RBCs do not have a nucleus (anucleate) * During development, the nucleus is lost from the cell * Gives cell more room for hemoglobin Develop from stem cells in red bone marrow * Move from bone marrow into blood while still immature Function of erythrocytes: * Transport oxygen and, to a lesser extent, carbon dioxide Hemoglobin * Makes up one third of each erythrocyte * Heme: Formed from a pigment that contains iron * Globin: Protein * Heme combines with oxygen in the lungs: oxyhemoglobin (bright red) * Oxygen is released to diffuse into tissue cells: Deoxyhemoglobin (darker red in color)

Answer 37

Negative feedback mechanism Erythropoietin: Stimulates erythrocyte production (erythropoisesis) Liver produces erythropoietin in inactive form * Secretes it into blood Renal erythropoietic factor (REF): Activates erythropoietin When blood oxygen concentration is low, kidneys release REF into blood—activates erythropoietin Stimulates red bone marrow to produce RBCs Additional RBCs combine with oxygen * Increases blood oxygen concentration As blood oxygen concentration increases, levels of REF and active erythropoietin decrease—RBC production decreases Needed for RBC production * Iron * Vitamin B12 * Folic acid Intrinsic factor - Produced by stomach - Needed for absorption of vitamin B12 in the intestines - Without intrinsic factor, vitamin B12 cannot be absorbed * Results in pernicious anemia

Answer 38

Lifespan of an erythrocyte: 120 days As erythrocyte ages, cell membrane becomes fragile Macrophages (phagocytic cells in spleen and liver) remove them from circulation Replaced by an equal number of new cells * 2 million erythrocytes are destroyed and replaced every second Hemoglobin separates into heme and globulin * Heme broken down into iron compound used to make new hemoglobin, bilirubin (yellow bile pigment) * Globin (protein) broken down into amino acids and added to supply of amino acids available in body

Answer 39

Characteristics and functions of WBCs - Larger than erythrocytes - Fewer in number - Normal WBC count: 4,500-11,000 cells/mm3 - Derived from hemocytoblast stem cells * Do not lose their nuclei Leukocytes do most of their work in the tissues * Use blood as transport medium * Move through capillary walls into tissue spaces: Diapedesis Provide a defense against organisms that cause disease

Answer 40

Granules in the cytoplasm - Neutrophils - Eosinophils - Basophils

Answer 41

No granules in the cytoplasm - Lymphocytes - Monocytes

Answer 42

Normal range: 50%-70% of WBCs Purple, multilobed nucleus (3-5 lobes) Many fine granules in cytoplasm * Stain violet-pink Band: Immature neutrophil * Curved, nonsegmented nuclei * 0%-5% of neutrophils normally present in band form First leukocytes to respond to tissue damage Engulf bacteria by phagocytosis Neutrophils and bands increase during acute infections

Answer 43

Normal range: 1%-4% of WBCs Segmented nucleus (no more than two lobes) Large granules in the cytoplasm: stain bright reddish orange Function: * Neutralize histamine—number increases during allergic reactions * Destroy parasitic worms

Answer 44

Normal range: 0%-1% of WBCs S-shaped nucleus Large, coarse granules in cytoplasms * Stain dark bluish-black * Almost completely obscure details of nucleus Secrete histamine and heparin * Histamine: Dilates blood vessels * Heparin: Inhibits blood clot formation

Answer 45

Normal range: 20%-35% of WBCs Large round or slightly indented nucleus * Stains a deep purplish blue Small rim of sky-blue cytoplasm around nucleus Produces antibodies Increase in lymphocytes occurs with certain viral diseases * Infectious mononucleosis, mumps, chicken pox, rubella, viral hepatitis

Answer 46

Largest WBC Normal range: 3%-8% of WBCs U-shaped or kidney-shaped nucleus * Surrounded by abundant cytoplasm * Stains grayish-blue Macrophages: Monocytes that leave the blood and enter the tissues * Engulf bacteria and cellular debris * Finishes the cleanup process started by neutrophils

Answer 47

Also known as platelets Consist of small fragments of large cells: Megakaryocytes Develop from hemocytoblasts in red bone marrow Normal range: 150,000 to 500,000 platelets/mm3 of blood Function: - Close breaks in blood vessels * Become sticky and clump together to form platelet plugs Initiate the formation of blood clots

Answer 48

Blood vessels that are torn or cut permit blood to escape into surrounding tissues or to outside of the body - Excessive blood loss may result in death Injured blood vessels trigger reactions to minimize blood loss and tissue damage Hemostasis: The stoppage of bleeding - Consists of three processes * Vascular constriction * Platelet plug formation * Coagulation

Answer 49

First response to blood vessel injury Contraction of smooth muscle in vessel walls (constriction) - Restricts flow of blood through opening in the vessel - Lasts only a few minutes - Allows enough time for other aspects of hemostasis to begin Platelets secrete a chemical: Serotonin - Stimulates smooth muscle contraction in vessel wall * Prolongs the vascular constriction

Answer 50

Normally platelets do not: - Stick to each other - Stick to blood vessel walls When blood vessel breaks: - Underlying connective tissue is exposed - Attracts platelets * Accumulate in damaged region * Adhere to connective tissue and each other Creates a platelet plug * Obstructs tear in the vessel

Answer 51

Formation of a blood clot Procoagulants: Factors in the blood that promote clotting Anticoagulants: Factors in the blood that inhibit clotting Normally anticoagulants override procoagulants * Blood remains fluid and does not clot When vessels damaged, procoagulants increase activity. Results in the formation of a clot. Involves a series of chemical reactions - Platelets and damaged tissues release chemicals * Initiate a series of reactions * Result in formation of prothrombin activator In the presence of calcium ions and prothrombin activator, prothrombin (inactive) is converted thrombin (active) Thrombin converts fibrinogen (inactive) fibrin (active) * Fibrin threads form a mesh After a clot has formed: - Fibrin strands contract: Clot retraction * Causes clot to shrink - Fibroblasts migrate into clot * Form fibrous connective tissue—repairs damaged area - Clot is eventually dissolved: Fibrinolysis

Answer 52

Based on the presence or absence of certain antigens on the surface of RBC membrane Blood types are inherited Blood types - Type A: A antigen - Type B: B antigen - Type AB (universal recipient): A and B antigens - Type O (universal donor): Neither A nor B antigens Certain blood antibodies develop in plasma shortly after birth - Type A blood * B antibodies - Type B blood * A antibodies - Type AB blood * Neither A nor B antibodies - Type O blood * A and B antibodies Blood type is the same antigen and opposite antibody

Answer 53

First studied in rhesus monkey Rh positive (Rh+): Rh antigen - 85% of population Rh negative (Rh–): Do not have Rh antigen - 15% of population Inherited trait Normally, neither Rh+ nor Rh individuals have Rh antibodies - If Rh– person is exposed to Rh+ blood (through blood transfusion or transfer of blood between a mother and fetus) * Individual develops Rh antibodies - If exposed to Rh+ blood a second time * Transfusion reaction results

Answer 54

Channels through which blood is distributed to body tissues Pulmonary vessels transport blood from right ventricle to lungs and back to left atrium Systemic vessels carry blood from left ventricle to all parts of the body and then return it to right atrium

Answer 55

Carry blood away from heart Pulmonary arteries transport blood that has a low oxygen content - From right ventricle to lungs Systemic arteries transport oxygenated blood from left ventricle to body tissues Blood is pumped from ventricles into large elastic arteries - Branch repeatedly into smaller arteries * Branching results in microscopic arteries: Arterioles Artery wall - Tunica intima: Innermost layer - Tunica media: Middle layer * Consists of smooth muscle * Usually the thickest layer * Provides support for the vessel * Changes vessel diameter—to regulate blood flow and blood pressure - Tunica externa: Outermost layer

Answer 56

Smallest and most numerous of the blood vessels Form connection between - Vessels that carry blood away from the heart (arteries) - Vessels that return blood to heart (veins) Capillary wall consists of a thin endothelium (one cell layer) Permits exchange of materials between * Blood in the capillary * Adjacent tissue cells Capillary is so small, erythrocytes must pass through them in single file Slows blood flow * Allows time for transport of substances across capillary endothelium

Answer 57

Carry blood toward heart After blood passes through capillaries: Enters the smallest veins: venules Flows into progressively larger veins until reaches the heart Vein walls - Same three layers as the arteries - Less smooth muscle and connective tissue * Makes walls of veins thinner and less rigid than those of arteries * Blood in the veins has less pressure than blood in the arteries * Veins can hold more blood: holds 70% of the total blood volume Venous valves - Located in medium and large veins - Keep blood flowing toward heart

Answer 58

The blood vessels of the body are functionally divided into two distinct circuits - Pulmonary circuit - Systemic circuit

Answer 59

Transports blood from right side of the heart to lungs -- Then returns it to left side of heart Contains oxygen-poor blood (increased levels of carbon dioxide) Pathway for pulmonary circuit - Blood is returned to right atrium from the tissue cells of the body - Blood passes through tricuspid valve into right ventricle - During ventricular systole * Blood is ejected through pulmonary SL valve into pulmonary trunk * Divides into right and left pulmonary arteries - Each pulmonary artery enters a lung * Divides into smaller vessels until they become capillaries - Capillaries of the lungs form networks * Surround the air sacs: Alveoli CO2 diffuses from capillary blood into alveoli O2 diffuses from alveoli into blood Oxygenated blood enters pulmonary venules * Form progressively larger veins until two pulmonary veins emerge from each lung - Blood is carried to left atrium In pulmonary circuit: - Arteries carry deoxygenated blood away from heart - Veins carry oxygenated blood to heart

Answer 60

Provides blood supply to all body tissues Carries oxygen and nutrients to cells Picks up carbon dioxide and waste products Carries oxygenated blood from left ventricle through the arteries to the capillaries in the tissues From tissue capillaries, deoxygenated blood returns through a system of veins to right atrium

Answer 61

Three primary functions - Returns excess interstitial fluid to the blood to maintain homeostasis - Fats and fat-soluble vitamins are absorbed from the intestinal tract into specialized lymph capillaries - Defense against invading microorganisms and disease Fluid in the lymphatic vessels Derived from blood plasma - Some plasma escapes at the arteriole end of a capillary - Most reenters the venule end of the capillary, but 10% remains in the tissue space as interstitial fluid - As fluid accumulates, tiny lymph vessels pick it up and it becomes lymph

Answer 62

Carry fluid away from the tissues and return it to the venous system Lymph capillaries merge to form larger and larger vessels until it reaches two lymphatic ducts - Right lymphatic duct * Receives lymph from the upper right quadrant of the body and empties into the left subclavian vein - Thoracic duct * Drains lymph from the remaining three quadrants of the body and empties into the left subclavian vein Lymph nodes are located along the various vessels of the lymphatic system - Filter lymph Walls are thin and have valves No pressure, so flow is sporadic and sluggish Obstructions may cause tissue fluid to accumulate, resulting in edema

Answer 63

Characterized by clusters of lymphocytes and other cells with a meshlike framework of connective tissue fibers - When the body is exposed to foreign substances - Lymphocytes proliferate then enter blood and travel to the site of the foreign substance

Answer 64

Small bean-shaped structures located along lymphatic vessels Filter lymph as it flows through the vessels so it is cleansed by lymphocytes and macrophages Three superficial regions of clusters * Inguinal nodes: Groin region * Axillary nodes: Armpit * Cervical node: Neck

Answer 65

- Cluster of lymphatic tissue under mucous membrane of the nose, mouth, and throat Pharyngeal tonsils: Near opening of nasal cavity in the pharynx, adenoids Palatine tonsils: Near opening of oral cavity into the pharynx Lingual tonsils: Near the base of the tongue Protect against pathogens that may enter the body through the nose and mouth

Answer 66

Located in the upper left quadrant of abdominal cavity, under diaphragm and behind stomach Largest lymphatic organ Filters blood like lymph node filters lymph Acts as a reservoir for blood and destroys old erythrocytes

Answer 67

Soft, two-lobed organ located anterior to ascending aorta, posterior to the sternum - Large in infants and children, decreases in size after puberty - Primary function is the maturation of special lymphocytes called T lymphocytes - Produces hormone thymosin, stimulates maturation of lymphocytes in other organs

Answer 68

Provide initial defense against invading agents - First line of nonspecific defense -- Intact of unbroken skin or mucous membranes -- Motion of fluids, such as tear, saliva, and urine -- Chemical protection against invaders - Second line of nonspecific defense -- Chemicals such as interferon and complement, phagocytosis, and inflammation - Primary cells involved in immunity are lymphocytes and macrophages

Answer 69

- Programmed to be selective and act against specific pathogens—“specificity” - System remembers invading agents to launch quicker attack—“memory” - Lymphocytes must recognize the difference between “self” and “non-self” -- “Non-self” molecules are called antigens -- An immune response triggered against “self”— autoimmune diseases -- T lymphocytes—responsible for cell-mediated immunity -- B lymphocytes—responsible for antibody-mediated immunity

Answer 70

T cells directly attack invading antigens Most effective against virus-infected cells, cancer cells, foreign tissue cells, fungi, and protozoan parasites Foreign antigens are present to T cells with receptors for that antigen—T cell divided into 4 clones Killer T cells—directly destroy the cells with offending antigen Helper T cells—stimulate B cells and promote immune response Suppressor T cells—inhibit B cells and immune response Memory T cells—promote a fast and more intense response upon reexposure

Answer 71

B cells are responsible for production of antibodies to inactivate invading antigens Can be called humoral immunity Most effective against bacteria, viruses outside body cells, and toxins—involved in allergic reactions Foreign antigens presented to specific B cells and helper T cells with correct receptors Helper T cells stimulate B cells to form two clones -- Plasma cells—produce antibodies -- Memory B cells—promote a fast and more intense response upon reexposure

Answer 72

Each antibody is only capable of reacting with a specific antigen.  Five types of immunoglobulins - IgA - IgG - IgM - IgE - IgD

Answer 73

- Four ways to acquire immunity - Active immunity: Individual’s own body responds and produces memory cells - Passive immunity: Immune agents are transferred to an individual - Natural immunity: Immunity is acquired through normal everyday living - Artificial immunity: Deliberate action is taken to acquire immunity (vaccination)

Answer 74

- Numerous “age-related” changes occur in the heart - Cardiac changes that were once thought to be result of aging are now believed to be the consequence of being sedentary - Difficult to isolate aging process of the heart

Chapter 12 : Circulatory System Flashcards

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