Chapter 44: The Circulatory System

1.

Question: Circulatory System components (Cardiovascular system) Answer: Heart (four-chambered muscular pump), Blood vessels, Blood

2.

Question: Circulatory System components (Lymphatic system) Answer: Collects excess interstitial fluid (IF or ECF)

3.

Question: Heart valves function Answer: Prevent backflow of blood

4.

Question: Atrioventricular valves (AV valves) Answer: Located between the atrium and the ventricle

5.

Question: Right AV valve Answer: Tricuspid valve

6.

Question: Left AV valve Answer: Mitral valve

7.

Question: Semilunar valves Answer: Aortic and pulmonary semilunar valves

8.

Question: Pulmonary circuit blood flow Answer: Right atrium receives deoxygenated blood from the body

9.

Question: Systemic circuit blood flow Answer: Carries oxygenated blood to the body

10.

Question: Anatomical organization of arteries and veins study Answer: Study the tunics (Tunica adventitia, Tunica media, Tunica intima) and how they differ

11.

Question: Branching of blood vessels Answer: Arteries-arterioles-capillaries-venules-smaller veins-large veins

12.

Question: Animal Circulatory Systems primary function Answer: Transport nutrients and gases through the body

13.

Question: Basic Elements of Circulatory Systems in Complex Animals Answer: Fluid, Heart, Vessels

14.

Question: Open Circulatory System Answer: Vessels leaving the heart release hemolymph directly into body spaces (sinuses or hemocoel)

15.

Question: Hemolymph Answer: Blood-like fluid in open circulatory systems, mixes with interstitial fluid

16.

Question: Open Circulatory System in Arthropods Answer: Hemolymph spills out of blood vessels into sinuses, making up the hemocoel

17.

Question: Open Circulatory System in most Mollusks (Heart) Answer: Three chambers: two atria receive hemolymph from gills, single ventricle pumps to sinuses

18.

Question: Closed Circulatory System Answer: Blood is confined to blood vessels and is distinct from the interstitial fluid

19.

Question: Substances exchange in Closed Circulatory System Answer: Between blood and interstitial fluid, then between interstitial fluid and cells

20.

Question: Amphibian Heart Answer: Three-chambered heart with two atria and one ventricle

21.

Question: Amphibian Heart (Oxygenated blood) Answer: From lungs and skin enters the left atrium

22.

Question: Amphibian Heart (Deoxygenated blood) Answer: From the body enters the right atrium

23.

Question: Avian and Mammalian Heart Answer: Four-chambered heart (two atria and two ventricles), double heart with separate pulmonary and systemic circuits

24.

Question: Systemic Circulatory System Answer: Transports blood to organs, tissues, and cells throughout the body

25.

Question: Pulmonary Circulatory System Answer: Moves blood between the heart and lungs for oxygen and carbon dioxide exchange

26.

Question: Human blood components (Formed elements) Answer: Erythrocytes (RBCs), leukocytes (WBCs), and platelets suspended in plasma

27.

Question: Human blood functions Answer: Transports cells and molecules, stabilizes pH and salt composition, regulates body temperature

28.

Question: Blood plasma components (major) Answer: Water (90%)

29.

Question: Blood plasma components (other) Answer: Glucose, amino acids, plasma proteins, dissolved gases, ions, lipids, vitamins, hormones, metabolic wastes

30.

Question: Blood cells developmental origin (adults) Answer: Red bone marrow (vertebrae, sternum, ribs, pelvis)

31.

Question: Blood cells originate from Answer: Multipotent stem cells

32.

Question: Multipotent stem cells differentiate into Answer: Myeloid stem cells and Lymphoid stem cells

33.

Question: Myeloid stem cells give rise to Answer: Erythrocytes, platelets, neutrophils, basophils, eosinophils, and monocytes

34.

Question: Lymphoid stem cells give rise to Answer: B lymphocytes and T lymphocytes

35.

Question: Plasma ions (most abundant) Answer: Na+ and Cl–

36.

Question: Erythrocytes life span (average) Answer: About 120 days

37.

Question: Erythrocytes destruction Answer: Engulfed by macrophages in spleen, liver, and bone marrow

38.

Question: Erythrocyte number control Answer: Negative feedback mechanism

39.

Question: Human blood groups determined by Answer: Antigens (glycoproteins) on erythrocyte surfaces (agglutinogens)

40.

Question: Leukocytes (white blood cells) functions Answer: Eliminate dead/dying cells, remove debris, defend against invaders

41.

Question: Blood platelets (thrombocytes) function Answer: Take part in blood clotting

42.

Question: Mammalian heart structure Answer: Four-chambered muscular pump (two atria, two ventricles)

43.

Question: Heart location Answer: Chest, above diaphragm in mediastinum, posterior to sternum in pericardial cavity

44.

Question: Heart chambers (Atria) Answer: Small, thin-walled, receive blood from veins/lungs, then contract

45.

Question: Heart valves groups Answer: Atrioventricular (AV) valves and Semilunar (SL) valves

46.

Question: AV valves function Answer: Prevent backflow from ventricles to atria

47.

Question: Tricuspid valve location Answer: Between the right atrium and right ventricle

48.

Question: Mitral valve location Answer: Between the left atrium and left ventricle

49.

Question: SL valves function Answer: Prevent backflow into ventricles

50.

Question: Pulmonary valve location Answer: Between the right ventricle and the pulmonary trunk

51.

Question: Aortic valve location Answer: Between the left ventricle and the aorta

52.

Question: Heart sounds "lub" (S1) Answer: Closure of the AV valves

53.

Question: Heart sounds "dub" Answer: Closure of the SL valves

54.

Question: Pulmonary circuit flow Answer: Deoxygenated blood from right ventricle to lungs

55.

Question: Systemic circuit flow (from heart) Answer: Oxygenated blood from left ventricle throughout the body

56.

Question: Superior vena cava carries blood from Answer: Head and forelimbs to heart

57.

Question: Inferior vena cava carries blood from Answer: Abdominal organs and hind limbs to heart

58.

Question: Pulmonary artery carries Answer: Deoxygenated blood from the right ventricle to the lungs

59.

Question: Aorta carries Answer: Oxygenated blood through systemic circuit

60.

Question: Coronary arteries function Answer: Supply oxygenated blood to the cardiac muscle cells

61.

Question: Coronary veins function Answer: Empty into the right atrium

62.

Question: Neurogenic hearts Answer: Beat under control of nervous system

63.

Question: Myogenic hearts (mammals) Answer: Contraction initiated by specialized cardiac muscle cells

64.

Question: Cardiac Conduction System Answer: Network of specialized cardiac muscle cells that initiates and distributes electrical impulses

65.

Question: Cardiac Cycle Answer: Sequence of events that occur and repeat with every heartbeat (Systole: ventricular contraction, Diastole: ventricular relaxation)

66.

Question: Blood flow direction Answer: From higher pressure to lower pressure

67.

Question: Atrioventricular node (AV node) location Answer: Heart wall between the right atrium and right ventricle

68.

Question: AV node function Answer: Excited by atrial contraction, generates signal to bottom of heart (Bundle of His, Purkinje fibers)

69.

Question: Bundle of His and Purkinje fibers function Answer: Provide the heart’s conducting system for synchronized ventricular contraction

70.

Question: Electrical Conduction Pathway of the Heart Answer: SA node (origin) – Atria – AV node – Bundle of His – Bundle branches – Purkinje fibers – Myocardial cells of the ventricles

71.

Question: Electrocardiogram (ECG/EKG) Answer: Graphic record of the heart’s electrical activity (conduction of impulses)

72.

Question: ECG represents Answer: Electrical events that precede heart contractions

73.

Question: Atrial depolarization (ECG wave) Answer: P-wave

74.

Question: P-wave represents Answer: Firing of the SA node stimulating atrial depolarization and contraction

75.

Question: PR interval represents Answer: Time for electrical waves to conduct from SA node to AV node

76.

Question: QRS complex represents Answer: Ventricular depolarization and contraction

77.

Question: T-wave represents Answer: Ventricular repolarization

78.

Question: Measuring Blood Pressure instrument Answer: Sphygmomanometer (inflatable cuff and pressure gauge) and stethoscope

79.

Question: Systolic pressure Answer: Artery maximally stretched during ventricular contraction

80.

Question: Diastolic pressure Answer: Artery recoils no further during ventricular relaxation

81.

Question: Pulse pressure Answer: Additional pressure from heart relaxing to contracting

82.

Question: Veins function Answer: Conduct blood away from organs/tissues and return it to the heart

83.

Question: Veins blood volume at rest Answer: 70% of total blood volume

84.

Question: Veins tunics Answer: Tunica intima, Tunica media, Tunica adventitia (same three layers as arteries)

85.

Question: Veins vs. Arteries (walls) Answer: Thinner walls with little elastin

86.

Question: Veins contain Answer: Interior one-way valves to keep blood flowing toward the heart

87.

Question: Veins as blood reservoirs Answer: Thin walls expand/contract over a wide range

88.

Question: Blood flow rate (total) Answer: Equal to the cardiac output

89.

Question: Blood flow velocity vs. cross-sectional area Answer: Inversely related

90.

Question: Blood flow velocity (highest) Answer: Aorta (smallest cross-sectional area)

91.

Question: Blood flow velocity (lowest) Answer: Capillaries (largest total cross-sectional area)

92.

Question: Endothelium tissue type Answer: Simple squamous epithelium

93.

Question: Cardiac Output (CO) Answer: Heart rate × Stroke volume

94.

Question: Factors determining blood pressure (transcript) Answer: Cardiac output, Total peripheral resistance (TPR), Total blood volume

95.

Question: Total Peripheral Resistance (TPR) Answer: Degree of constriction of blood vessels; determines diastolic pressure

96.

Question: Short-term blood pressure regulation Answer: Sympathetic autonomic nervous system, Endocrine system (epinephrine, norepinephrine)

97.

Question: Long-term blood pressure regulation Answer: Renin-Angiotensin-Aldosterone System (RAAS)

98.

Question: Baroreceptors Answer: Stretch receptors in walls of blood vessels (aorta, carotid sinus) and cardiac muscle

99.

Question: Baroreceptors function Answer: Constantly provide information about blood pressure to the medulla

100.

Question: Low blood pressure effect on baroreceptors (transcript) Answer: Activates cardioaccelerator center, increases sympathetic activity, increases heart rate and stroke volume

101.

Question: High blood pressure effect on baroreceptors (transcript) Answer: Activates cardioinhibitory center, increases parasympathetic activity, decreases heart rate

102.

Question: Chemoreceptors location Answer: Aorta and carotid arteries

103.

Question: Chemoreceptors function Answer: Detect O2 content of the blood

104.

Question: Low O2 concentration effect (transcript) Answer: Brain stem increases heart rate and force of heartbeat

105.

Question: Lymphatic system function Answer: Helps balance fluid content of blood and participates in body’s defenses

106.

Question: Lymph nodes function Answer: Monitor and cleanse lymph, contain macrophages and lymphocytes

107.

Question: Lymph nodes contain Answer: Macrophages (phagocytes) and Lymphocytes (produce antibodies)

108.

Question: What are the components of the circulatory system? Answer: C. Heart, blood vessels, and fluid

109.

Question: Which system helps balance the fluid content of the blood and participates in the body’s defenses against invading disease organisms? Answer: The lymphatic system

110.

Question: Atherosclerosis Answer: Development of fatty streaks and plaques inside major arteries (thickening of the walls - arteriosclerosis)

111.

Question: Risks of Atherosclerosis Answer: Carotid artery plaque (stroke/CVA), Coronary artery plaque (heart attack/MI), Peripheral artery disease

112.

Question: Endothelium tissue Answer: Simple squamous epithelium

113.

Question: Cardiac output (CO) calculation Answer: Heart rate × Stroke volume (amount of blood pumped per minute)

114.

Question: Systolic pressure regulation (transcript) Answer: Primarily determined by cardiac output

115.

Question: Diastolic pressure regulation (transcript) Answer: Primarily regulated by total peripheral resistance (TPR)

116.

Question: Treatment for high systolic pressure (transcript) Answer: Drugs that reduce or regulate cardiac output

117.

Question: Treatment for high diastolic pressure (transcript) Answer: Drugs that reduce total peripheral resistance (vasodilation)

118.

Question: High fluid volume/blood volume effect (transcript) Answer: Higher blood pressure

119.

Question: Low fluid volume/blood volume effect (transcript) Answer: Lower blood pressure

120.

Question: Short-term blood pressure regulation mechanisms (transcript) Answer: Baroreceptor reflex, Chemoreceptor reflex, Endocrine (epinephrine/norepinephrine)

121.

Question: Barrow receptor locations (transcript) Answer: Aorta, Carotid sinus, Walls of the heart (cardiac muscle)

122.

Question: Chemoreceptor responses (low oxygen) (transcript) Answer: Increase secretion of vasodilators, increase heart rate and force

123.

Question: Adrenal medulla and blood pressure (transcript) Answer: Secretes epinephrine and norepinephrine, which increase heart rate and stroke volume

124.

Question: Lymphoid tissue examples (secondary) (transcript) Answer: Spleen, lymph nodes, tonsils, MALT (mucosa-associated lymphatic tissue), appendix

125.

Question: Lymph node clusters (transcript) Answer: Neck, axillary region, groin, abdominal, chest cavities

126.

Question: Cardiac Cycle: Steps Answer: Atrial depolarization (P-wave), Atrial contraction, AV node delay, Ventricular depolarization (QRS complex), Ventricular contraction, Isovolumetric contraction, Ventricular ejection, Ventricular repolarization (T-wave), Isovolumetric relaxation, Atrial filling

127.

Question: Electrical Conduction Pathway: Steps Answer: SA node fires, Atrial depolarization, AV node delay, Impulse travels down Bundle of His, Bundle branches, Purkinje fibers, Ventricular depolarization

128.

Question: Developmental Origins of Blood Cells: Steps Answer: Multipotent stem cell, Myeloid stem cell lineage OR Lymphoid stem cell lineage, Differentiation into specific blood cell types

129.

Question: Open Circulatory System: Process Answer: Heart pumps hemolymph into sinuses/hemocoel, Hemolymph bathes organs directly, Re-enters heart through valves (ostia in some)

130.

Question: Closed Circulatory System: Process Answer: Heart pumps blood through vessels, Exchange of substances occurs between blood and interstitial fluid, then between interstitial fluid and cells, Blood returns to the heart

131.

Question: Blood flow through the heart (simplified) Answer: Body -> Right Atrium -> Right Ventricle -> Lungs -> Left Atrium -> Left Ventricle -> Body

132.

Question: Blood vessel tunics Answer: Tunica Intima (innermost), Tunica Media (middle), Tunica Adventitia/Externa (outermost)

133.

Question: Arteries vs. Veins (lumen) Answer: Arteries have smaller lumen; Veins have larger lumen

134.

Question: Arteries vs. Veins (elastic tissue) Answer: Arteries have more elastic tissue

135.

Question: Capillaries structure Answer: Single layer of endothelium

136.

Question: Precapillary sphincters Answer: Smooth muscle cuffs regulating blood flow into capillaries

137.

Question: Velocity of blood flow Answer: Highest in aorta, lowest in capillaries

138.

Question: Erythropoiesis regulation Answer: Hypoxia -> Kidneys release Erythropoietin (EPO) -> Bone marrow stimulates RBC production

139.

Question: Hemoglobin components Answer: Four polypeptide chains (two alpha, two beta), each with a heme group containing iron

140.

Question: Heme function Answer: Binds and carries oxygen

141.

Question: Breakdown of Erythrocytes: Steps Answer: Macrophages in spleen/liver/bone marrow engulf old RBCs, Hemoglobin broken down into heme and globin, Iron recycled, Heme converted to bilirubin, Bilirubin processed by liver, excreted in bile/urine/feces

142.

Question: Blood Plasma composition (by volume) Answer: Water (90%), Plasma proteins (7-9%), Other solutes (1-2%)

143.

Question: Major Plasma Proteins Answer: Albumins, Globulins, Fibrinogen

144.

Question: Formed Elements of Blood (Percentages approx.) Answer: Erythrocytes (99%), Leukocytes (<1%), Platelets (<1%)

145.

Question: Leukocyte types Answer: Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils

146.

Question: Platelet formation Answer: Fragments of megakaryocytes in bone marrow

147.

Question: Vasoconstriction Answer: Narrowing of blood vessels, increases blood pressure

148.

Question: Vasodilation Answer: Widening of blood vessels, decreases blood pressure

149.

Question: Arteries carry blood Answer: Away from the heart (usually oxygenated, except pulmonary artery)

150.

Question: Veins carry blood Answer: Towards the heart (usually deoxygenated, except pulmonary veins)

151.

Question: Single Circulation (Fish) Answer: Blood passes through the heart only once per circuit (heart -> gills -> body -> heart)

152.

Question: Double Circulation (Mammals, Birds) Answer: Blood passes through the heart twice per circuit (pulmonary and systemic circuits)

153.

Question: Three-chambered heart (Amphibians, Reptiles) Answer: Two atria and one ventricle, allows mixing of oxygenated and deoxygenated blood (less in reptiles due to partial septum)

154.

Question: Four-chambered heart (Mammals, Birds, Crocodilians) Answer: Two atria and two completely separate ventricles, prevents mixing of oxygenated and deoxygenated blood

155.

Question: SA Node (Sinoatrial Node) Answer: Pacemaker of the heart, initiates electrical impulses

156.

Question: AV Node (Atrioventricular Node) function (detailed) Answer: Receives impulse from SA node, delays it, then sends it to the ventricles

157.

Question: Purkinje Fibers function (detailed) Answer: Rapidly conduct impulses throughout the ventricular myocardium, causing coordinated contraction

158.

Question: ECG Waves represent (detailed) Answer: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization)

159.

Question: Blood Pressure Measurement (Korotkoff sounds) Answer: Sounds heard through a stethoscope when measuring blood pressure, resulting from turbulent blood flow through a compressed artery

160.

Question: Lymph Answer: Excess interstitial fluid collected by lymphatic vessels

161.

Question: Lymphatic Vessels Answer: Vessels that carry lymph towards the heart, have valves to prevent backflow

162.

Question: Immune function of Lymphatic System Answer: Lymph nodes filter lymph for pathogens and cancerous cells; lymphocytes initiate immune responses

163.

Question: Arterioles Answer: Small arteries that regulate blood flow to capillaries

164.

Question: Venules Answer: Small veins that collect blood from capillaries

165.

Question: Blood Brain Barrier Answer: Selective barrier formed by tight junctions in brain capillaries, restricting substance movement

166.

Question: Gas Exchange in Capillaries Answer: Oxygen and nutrients move out of blood into interstitial fluid and tissues; Carbon dioxide and wastes move from tissues into blood via diffusion

167.

Question: Myocardial Infarction (Heart Attack) Answer: Damage to heart muscle due to lack of blood supply, often caused by blocked coronary arteries

168.

Question: Stroke (Cerebrovascular Accident) Answer: Damage to brain tissue due to interrupted blood supply, can be caused by blocked or burst arteries

169.

Question: Hypertension Answer: Abnormally high blood pressure

170.

Question: Hypotension Answer: Abnormally low blood pressure

171.

Question: Blood Typing Antigens Answer: Glycoproteins on the surface of red blood cells (e.g., A antigen, B antigen)

172.

Question: Blood Typing Antibodies Answer: Antibodies in plasma that react with foreign blood antigens (e.g., Anti-A, Anti-B)

173.

Question: Universal Blood Donor Answer: Type O negative (O-) because it lacks A and B antigens

174.

Question: Universal Blood Recipient Answer: Type AB positive (AB+) because it has both A and B antigens and no plasma antibodies

175.

Question: Lymphatic System (one-way circuit) Answer: Lymph flows from tissues towards the heart; no circulation like blood.

176.

Question: Importance of gap junctions in cardiac muscle Answer: Allow rapid spread of ions and electrical signals, enabling synchronized contraction of heart muscle cells.

177.

Question: Function of AV node delay Answer: Allows the atria to contract completely and empty blood into the ventricles before ventricular contraction begins.

178.

Question: Importance of healthy lifestyle for blood vessels (transcript) Answer: Enough exercise, enough sleep, good food (healthy dietary regimen) can help prevent clogged arteries.

179.

Question: Treatment for atherosclerosis (transcript) Answer: Lifestyle changes (diet, exercise), medication, and procedures like stent insertion to maintain blood flow.

180.

Question: Cardiac output is the result of Answer: The pressure generated when the ventricles are contracting (systolic pressure).

181.

Question: Diastolic pressure is regulated by Answer: Total peripheral resistance (TPR).

182.

Question: Sympathetic nervous system effect on blood pressure (transcript) Answer: Increases heart rate, increases stroke volume, promotes vasoconstriction (increases blood pressure).

183.

Question: Parasympathetic nervous system effect on blood pressure (transcript) Answer: Decreases heart rate (decreases blood pressure).

184.

Question: Aldosterone function (transcript) Answer: Increases sodium reabsorption in kidney tubules, leading to increased water reabsorption and blood volume (long-term blood pressure regulation).

185.

Question: Cortisol function (transcript) Answer: Mineralocorticoid that increases sodium reabsorption (similar to aldosterone).