Chapter 44: The Circulatory System

Question: Circulatory System components (Cardiovascular system)

Answer: Heart (four-chambered muscular pump), Blood vessels, Blood

Lymphatic system function

Answer: Collects excess interstitial fluid (IF or ECF)

Question: Heart valves function

Answer: Prevent backflow of blood

Question: Atrioventricular valves (AV valves)

Answer: Located between the atrium and the ventricle

Question: Right AV valve

Answer: Tricuspid valve

Question: Left AV valve

Answer: Mitral valve

Question: Semilunar valves

Answer: Aortic and pulmonary semilunar valves

Question: Pulmonary circuit blood flow

Answer: Right atrium receives deoxygenated blood from the body

Question: Systemic circuit blood flow

Answer: Carries oxygenated blood to the body

Question: Anatomical organization of arteries and veins study

Answer: Study the tunics (Tunica adventitia, Tunica media, Tunica intima) and how they differ

Question: Branching of blood vessels

Answer: Arteries-arterioles-capillaries-venules-smaller veins-large veins

Question: Animal Circulatory Systems primary function

Answer: Transport nutrients and gases through the body

Question: Basic Elements of Circulatory Systems in Complex Animals

Answer: Fluid, Heart, Vessels

Question: Open Circulatory System

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

Question: Hemolymph

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

Question: Open Circulatory System in Arthropods

Answer: Hemolymph spills out of blood vessels into sinuses, making up the hemocoel

Question: Open Circulatory System in most Mollusks (Heart)

Answer: Three chambers: two atria receive hemolymph from gills, single ventricle pumps to sinuses

Question: Closed Circulatory System

Answer: Blood is confined to blood vessels and is distinct from the interstitial fluid

Question: Substances exchange in Closed Circulatory System

Answer: Between blood and interstitial fluid, then between interstitial fluid and cells

Question: Amphibian Heart

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

Question: Amphibian Heart (Oxygenated blood)

Answer: From lungs and skin enters the left atrium

Question: Amphibian Heart (Deoxygenated blood)

Answer: From the body enters the right atrium

Question: Avian and Mammalian Heart

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

Question: Systemic Circulatory System

Answer: Transports blood to organs, tissues, and cells throughout the body

Question: Pulmonary Circulatory System

Answer: Moves blood between the heart and lungs for oxygen and carbon dioxide exchange

Question: Human blood components (Formed elements)

Answer: Erythrocytes (RBCs), leukocytes (WBCs), and platelets suspended in plasma

Question: Human blood functions

Answer: Transports cells and molecules, stabilizes pH and salt composition, regulates body temperature

Question: Blood plasma components (major)

Answer: Water (90%)

Question: Blood plasma components (other)

Answer: Glucose, amino acids, plasma proteins, dissolved gases, ions, lipids, vitamins, hormones, metabolic wastes

Question: Blood cells developmental origin (adults)

Answer: Red bone marrow (vertebrae, sternum, ribs, pelvis)

Question: Blood cells originate from

Answer: Multipotent stem cells

Question: Multipotent stem cells differentiate into

Answer: Myeloid stem cells and Lymphoid stem cells

Question: Myeloid stem cells give rise to

Answer: Erythrocytes, platelets, neutrophils, basophils, eosinophils, and monocytes

Question: Lymphoid stem cells give rise to

Answer: B lymphocytes and T lymphocytes

Question: Plasma ions (most abundant)

Answer: Na+ and Cl–

Question: Erythrocytes life span (average)

Answer: About 120 days

Question: Erythrocytes destruction

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

Question: Erythrocyte number control

Answer: Negative feedback mechanism

Question: Human blood groups determined by

Answer: Antigens (glycoproteins) on erythrocyte surfaces (agglutinogens)

Question: Leukocytes (white blood cells) functions

Answer: Eliminate dead/dying cells, remove debris, defend against invaders

Question: Blood platelets (thrombocytes) function

Answer: Take part in blood clotting

Question: Mammalian heart structure

Answer: Four-chambered muscular pump (two atria, two ventricles)

Question: Heart location

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

Question: Heart chambers (Atria)

Answer: Small, thin-walled, receive blood from veins/lungs, then contract

Question: Heart valves groups

Answer: Atrioventricular (AV) valves and Semilunar (SL) valves

Question: AV valves function

Answer: Prevent backflow from ventricles to atria

Question: Tricuspid valve location

Answer: Between the right atrium and right ventricle

Question: Mitral valve location

Answer: Between the left atrium and left ventricle

Question: SL valves function

Answer: Prevent backflow into ventricles

Question: Pulmonary valve location

Answer: Between the right ventricle and the pulmonary trunk

Question: Aortic valve location

Answer: Between the left ventricle and the aorta

Question: Heart sounds "lub" (S1)

Answer: Closure of the AV valves

Question: Heart sounds "dub"

Answer: Closure of the SL valves

Question: Pulmonary circuit flow

Answer: Deoxygenated blood from right ventricle to lungs

Question: Systemic circuit flow (from heart)

Answer: Oxygenated blood from left ventricle throughout the body

Question: Superior vena cava carries blood from

Answer: Head and forelimbs to heart

Question: Inferior vena cava carries blood from

Answer: Abdominal organs and hind limbs to heart

Question: Pulmonary artery carries

Answer: Deoxygenated blood from the right ventricle to the lungs

Question: Aorta carries

Answer: Oxygenated blood through systemic circuit

Question: Coronary arteries function

Answer: Supply oxygenated blood to the cardiac muscle cells

Question: Coronary veins function

Answer: Empty cardiac muscle cell blood into the right atrium

Question: Neurogenic hearts

Answer: Beat under control of nervous system

Question: Myogenic hearts (mammals)

Answer: Contraction initiated by specialized cardiac muscle cells

Question: Cardiac Conduction System

Answer: Network of specialized cardiac muscle cells that initiates and distributes electrical impulses

Question: Cardiac Cycle

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

Question: Blood flow direction

Answer: From higher pressure to lower pressure

Question: Atrioventricular node (AV node) location

Answer: Heart wall between the right atrium and right ventricle

Question: AV node function

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

Question: Bundle of His and Purkinje fibers function

Answer: Provide the heart’s conducting system for synchronized ventricular contraction

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

Question: Electrocardiogram (ECG/EKG)

Answer: Graphic record of the heart’s electrical activity (conduction of impulses)

Question: ECG represents

Answer: Electrical events that precede heart contractions

Question: Atrial depolarization (ECG wave)

Answer: P-wave

Question: P-wave represents

Answer: Firing of the SA node stimulating atrial depolarization and contraction

Question: PR interval represents

Answer: Time for electrical waves to conduct from SA node to AV node

Question: QRS complex represents

Answer: Ventricular depolarization and contraction

Question: T-wave represents

Answer: Ventricular repolarization

Question: Measuring Blood Pressure instrument

Answer: Sphygmomanometer (inflatable cuff and pressure gauge) and stethoscope

Question: Systolic pressure

Answer: Artery maximally stretched during ventricular contraction

Question: Diastolic pressure

Answer: Artery recoils no further during ventricular relaxation

Question: Pulse pressure

Answer: Additional pressure from heart relaxing to contracting

Question: Veins function

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

Question: Veins blood volume at rest

Answer: 70% of total blood volume

Question: Veins tunics

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

Question: Veins vs. Arteries (walls)

Answer: Veins have thinner walls with little elastin

Question: Veins contain

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

Question: Veins as blood reservoirs

Answer: Thin walls expand/contract over a wide range

Question: Blood flow rate (total)

Answer: Equal to the cardiac output

Question: Blood flow velocity vs. cross-sectional area

Answer: Inversely related

Question: Blood flow velocity (highest)

Answer: Aorta (smallest cross-sectional area)

Question: Blood flow velocity (lowest)

Answer: Capillaries (largest total cross-sectional area)

Question: Endothelium tissue type

Answer: Simple squamous epithelium

Question: Cardiac Output (CO)

Answer: Heart rate × Stroke volume

Question: Factors determining blood pressure (transcript)

Answer: Cardiac output, Total peripheral resistance (TPR), Total blood volume

Question: Total Peripheral Resistance (TPR)

Answer: Degree of constriction of blood vessels; determines diastolic pressure

Question: Short-term blood pressure regulation

Answer: Sympathetic autonomic nervous system, Endocrine system (epinephrine, norepinephrine)

Question: Long-term blood pressure regulation

Answer: Renin-Angiotensin-Aldosterone System (RAAS)

Question: Baroreceptors

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

Question: Baroreceptors function

Answer: Constantly provide information about blood pressure to the medulla

Question: Low blood pressure effect on baroreceptors (transcript)

Answer: Activates cardioaccelerator center, increases sympathetic activity, increases heart rate and stroke volume