Blood Composition and Functions
Blood Overview
What is Blood?
Function: Blood transports oxygen, nutrients, hormones, and wastes. It is involved in processes such as clotting and fighting infections.
Importance: Key for transportation of substances to distant body locations. Clotting proteins found in blood prevent life-threatening bleeding from minor injuries.
Mechanism: Blood is moved through vessels by the pumping action of the heart. It contains different types of blood cells, including red blood cells (carry oxygen), clotting proteins (stop bleeding), and white blood cells (fight infections).
Composition and Functions of Blood (10.1)
Learning Objectives
Describe the composition and volume of whole blood.
Understand the composition of plasma and its role in the body.
Composition of Blood
Blood is a unique fluid tissue, consisting of:
Formed Elements: Living blood cells suspended in a liquid matrix.
Plasma: Nonliving fluid part that contains dissolved proteins visible as fibrin strands during clotting.
Separated blood components:
Plasma: Rises to the top
Formed Elements: Heavier components fall to the bottom
Erythrocytes (Red Blood Cells): Most of the bottom pellet; responsible for oxygen transport.
Buffy Coat: Thin whitish layer containing white blood cells and platelets.
Percentages of Blood Components
Erythrocytes: ~45% of blood volume (known as hematocrit).
White Blood Cells and Platelets: Less than 1%.
Plasma: ~55% of blood volume.
Physical Characteristics of Blood
Characteristics:
Texture: Sticky, opaque, heavier than water (5 times thicker).
Color: Varies from scarlet (oxygen-rich) to dull red/purple (oxygen-poor).
Taste: Characteristic metallic and salty.
pH: Slightly alkaline (7.35 - 7.45).
Temperature: 38°C (100.4°F); slightly higher than body temperature.
Volume: Approximately 8% of body weight; 5-6 liters in healthy adults.
Plasma Composition
Water: Approximately 90% of plasma volume; solvent for other substances.
Dissolved Substances: Over 100 types, including nutrients, salts, gases, hormones, proteins, and metabolic wastes.
Plasma Proteins: Most abundant solutes. Functions include:
Albumin: Carries molecules, blood buffer, maintains osmotic pressure.
Clotting Proteins: Prevent blood loss.
Antibodies: Protect against pathogens.
Plasma composition adjusts based on cell interaction, diet, and homeostatic mechanisms keeping levels constant despite fluctuations.
Formed Elements of Blood (10.1d)
Learning Objectives
List types of formed elements and their main functions.
Understand anemia, polycythemia, leukopenia, and leukocytosis and their causes.
Types of Formed Elements
Erythrocytes (Red Blood Cells)
Function: Transport oxygen and help carry carbon dioxide.
Count: Normally about 4-6 million cells/mm³.
Leukocytes (White Blood Cells)
Function: Body defense. Count ranges from 4,800 to 10,800/mm³.
Platelets
Function: Essential for blood clotting. Count ranges from 150,000 to 400,000/mm³.
Conditions related to Blood Components
Anemia: Decrease in RBCs or hemoglobin leading to insufficient oxygen transport.
Polycythemia: Excess of RBCs; increases blood viscosity, causing sluggish circulation.
Leukopenia: Deficiency of WBCs, often due to chemicals or diseases.
Leukocytosis: Increased WBC count, indicating infection.
Hematopoiesis (Blood Cell Formation) (10.1e)
Learning Objective
Explain the role of the hemocytoblast.
Hematopoiesis Process
Location: Occurs in red bone marrow concentrated in the axial skeleton, girdles, and epiphyses.
Stem Cells: Hemocytoblasts give rise to all blood cells, differentiating into either lymphoid (producing lymphocytes) or myeloid (producing other blood elements) cells.
Production Rate: Red marrow produces around 100 billion new blood cells daily.
Development of Red Blood Cells
RBCs lose their nuclei and organelles; they mature into reticulocytes before being released into circulation.
Erythropoietin hormone triggers RBC production in response to low oxygen levels.
Erythropoietin Mechanism
Feedback Control: Released by kidneys when blood oxygen is low, stimulating faster RBC production.
Blood Clotting Process (Hemostasis) (10.2)
Learning Objectives
Describe the hemostatic response when blood vessels break.
Hemostasis Overview
Process: Quick, localized series of reactions triggered by blood vessel injury, involving:
Substances normally in plasma
Released substances from platelets and damaged tissue cells.
Phases of Hemostasis: 1) Vascular spasm, 2) Platelet plug formation, 3) Coagulation (clot formation).
Key Components: Clotting factors, platelets, and endothelial cells engage in the process, ensuring effective blood loss prevention.
Factors Affecting Clotting
Enhancers: Tissue factors, activated platelets, and coagulation factors.
Inhibitors: Certain medications and conditions that alter normal clotting mechanisms, leading to either excessive clotting or bleeding conditions.
10.1 Composition and Functions of Blood
Composition and Volume of Whole Blood: Understand what whole blood consists of and its typical volume in the human body.
Plasma Composition and Role: Describe what plasma is made of and its functions within the body.
Types of Formed Elements: List the different cell types (erythrocytes, leukocytes, platelets) found in blood and outline their primary functions.
Blood Disorders: Define conditions such as anemia, polycythemia, leukopenia, and leukocytosis, including their causes and effects.
Role of the Hemocytoblast: Explain the function of hemocytoblasts in producing different types of blood cells.
10.2 Hemostasis
Blood-Clotting Process: Provide a detailed description of how blood clotting occurs when blood vessels are injured.
Factors Influencing Clotting: List factors that may affect the blood clotting process, including genetic and environmental elements.
10.1 Anemia in Kidney Disease
Why do many people with advanced kidney disease become anemic?
Low blood O₂-carrying ability leads to anemia due to:
Decreased Red Blood Cell (RBC) count
Decreased amount of hemoglobin
Decreased availability of O₂
Homeostatic Responses:
Stimulus - Low blood oxygen-carrying ability due to the reasons mentioned above.
Kidneys and Liver Response:
Kidneys (and liver to a smaller extent) release erythropoietin.
Erythropoietin Action:
Stimulates red bone marrow to produce more RBCs and enhance erythropoiesis.
Result:
Increases RBC count and restores oxygen-carrying capacity of blood.
10.1a Formation of White Blood Cells and Platelets
Stimulating Factors:
White blood cells (leukocytes) and platelets formation is stimulated by hormones known as colony stimulating factors (CSFs) and interleukins.
CSFs enhance the ability of mature leukocytes to protect the body by responding to specific signals such as inflammatory chemicals and certain bacteria.
Thrombopoietin:
Produced by the liver to accelerate the production of platelets from megakaryocytes.
Bone Marrow Biopsy:
Procedure to withdraw a small sample of red marrow from flat bones (e.g., ilium or sternum).
Used for microscopic examination to diagnose conditions like leukemia.
Did You Get It?
8. Name of the stem cell giving rise to all formed elements: Hematopoietic stem cell.
9. Property of RBCs limiting life span to about 120 days: Lack of nuclei and organelles.
10. Difference in platelet production: Platelet formation is regulated primarily by thrombopoietin, unlike other formed elements which have a more complex regulation involving erythropoietin and other factors.
10.2 Hemostasis
Learning Objectives
Describe the blood-clotting process.
Identify factors that inhibit or enhance the blood-clotting process.
Definition: Hemostasis (hem = blood; stasis = standing still) is the process of stopping bleeding when a blood vessel wall breaks.
10.2a Phases of Hemostasis
Three major phases involved:
Vascular Spasms:
Immediate vasoconstriction occurs to narrow the blood vessel and decrease blood loss.
Triggers include:
Direct injury to smooth muscle cells
Stimulation of local pain receptors
Release of serotonin from platelets.
Platelet Plug Formation:
Platelets become sticky and adhere to exposed collagen fibers of the damaged vessel.
Release chemicals that enhance vascular spasms and attract more platelets to the site, forming a platelet plug.
Coagulation Events:
Injured tissues release tissue factor (TF) which interacts with PF3 (platelet factor 3) and calcium ions (Ca²⁺).
This interaction forms thrombin, which converts fibrinogen (soluble) into fibrin (insoluble) to create a meshwork trapping RBCs and forming a clot.
Clot Formation Timeline: Blood clots within 3 to 6 minutes post-injury. Clot retracts within the hour to aid healing.
10.2b Disorders of Hemostasis
Imbalance Types:
Undesirable Clot Formation:
Clots can form in unbroken vessels, termed a thrombus.
Pulmonary thrombosis can cause fatal hypoxia if it blocks blood flow to the lungs.
An embolus is a traveling thrombus that can lodge in smaller vessels, potentially causing strokes or other critical issues.
Risks include:
Roughened endothelium
Physical blows or accumulation of fatty materials
Slow or pooling blood (often in immobilized patients).
Anticoagulants: Used clinically include aspirin, heparin, and warfarin.
Bleeding Disorders:
Common causes include:
Thrombocytopenia (deficiency of platelets)
Impaired liver function leading to deficits in clotting factors.
Thrombocytopenia: Results in spontaneous bleeding due to insufficient platelets. Characterized by petechiae (small purplish blotches).
Hemophilia: Various hereditary disorders resulting from lack of clotting factors, requiring plasma or clotting factor injections for treatment.
Vitamin K Deficiency: Can be corrected with supplements, whereas severe liver impairment may necessitate blood transfusions.
Did You Get It?
11. Factors enhancing thrombus formation: Roughened endothelium, slow blood flow, local pooling of blood.
10.1 Anemia in Kidney Disease
Why do many people with advanced kidney disease become anemic?
Low blood O₂-carrying ability leads to anemia due to:
Decreased Red Blood Cell (RBC) count
Decreased amount of hemoglobin
Decreased availability of O₂
Homeostatic Responses:
Stimulus - Low blood oxygen-carrying ability due to the reasons mentioned above.
Kidneys and Liver Response:
Kidneys (and liver to a smaller extent) release erythropoietin.
Erythropoietin Action:
Stimulates red bone marrow to produce more RBCs and enhance erythropoiesis.
Result:
Increases RBC count and restores oxygen-carrying capacity of blood.
10.1a Formation of White Blood Cells and Platelets
Stimulating Factors:
White blood cells (leukocytes) and platelets formation is stimulated by hormones known as colony stimulating factors (CSFs) and interleukins.
CSFs enhance the ability of mature leukocytes to protect the body by responding to specific signals such as inflammatory chemicals and certain bacteria.
Thrombopoietin:
Produced by the liver to accelerate the production of platelets from megakaryocytes.
Bone Marrow Biopsy:
Procedure to withdraw a small sample of red marrow from flat bones (e.g., ilium or sternum).
Used for microscopic examination to diagnose conditions like leukemia.
Did You Get It?
8. Name of the stem cell giving rise to all formed elements: Hematopoietic stem cell.
9. Property of RBCs limiting life span to about 120 days: Lack of nuclei and organelles.
10. Difference in platelet production: Platelet formation is regulated primarily by thrombopoietin, unlike other formed elements which have a more complex regulation involving erythropoietin and other factors.
10.2 Hemostasis
Learning Objectives
Describe the blood-clotting process.
Identify factors that inhibit or enhance the blood-clotting process.
Definition: Hemostasis (hem = blood; stasis = standing still) is the process of stopping bleeding when a blood vessel wall breaks.
10.2a Phases of Hemostasis
Three major phases involved:
Vascular Spasms:
Immediate vasoconstriction occurs to narrow the blood vessel and decrease blood loss.
Triggers include:
Direct injury to smooth muscle cells
Stimulation of local pain receptors
Release of serotonin from platelets.
Platelet Plug Formation:
Platelets become sticky and adhere to exposed collagen fibers of the damaged vessel.
Release chemicals that enhance vascular spasms and attract more platelets to the site, forming a platelet plug.
Coagulation Events:
Injured tissues release tissue factor (TF) which interacts with PF3 (platelet factor 3) and calcium ions (Ca²⁺).
This interaction forms thrombin, which converts fibrinogen (soluble) into fibrin (insoluble) to create a meshwork trapping RBCs and forming a clot.
Clot Formation Timeline: Blood clots within 3 to 6 minutes post-injury. Clot retracts within the hour to aid healing.
10.2b Disorders of Hemostasis
Imbalance Types:
Undesirable Clot Formation:
Clots can form in unbroken vessels, termed a thrombus.
Pulmonary thrombosis can cause fatal hypoxia if it blocks blood flow to the lungs.
An embolus is a traveling thrombus that can lodge in smaller vessels, potentially causing strokes or other critical issues.
Risks include:
Roughened endothelium
Physical blows or accumulation of fatty materials
Slow or pooling blood (often in immobilized patients).
Anticoagulants: Used clinically include aspirin, heparin, and warfarin.
Bleeding Disorders:
Common causes include:
Thrombocytopenia (deficiency of platelets)
Impaired liver function leading to deficits in clotting factors.
Thrombocytopenia: Results in spontaneous bleeding due to insufficient platelets. Characterized by petechiae (small purplish blotches).
Hemophilia: Various hereditary disorders resulting from lack of clotting factors, requiring plasma or clotting factor injections for treatment.
Vitamin K Deficiency: Can be corrected with supplements, whereas severe liver impairment may necessitate blood transfusions.
The Cardiovascular System
Overview of the Cardiovascular System
Definition: The cardiovascular system delivers oxygen and nutrients to body tissues and removes waste products like carbon dioxide through the blood.
Importance:
If the cardiovascular system fails, waste accumulates in the tissues.
Organs cannot function properly; depletion of oxygen leads to organ failure and death.
Mechanism of Action:
The heart pumps blood throughout the body via blood vessels.
Blood flow relies on the heart's pumping action and changes in blood pressure.
Heart and Blood Vessels
Common Perception: Many people equate the cardiovascular system solely with the heart, although it comprises more components including blood vessels which serve as pathways for blood transport.
Continuous Exchange: The body's cells constantly uptake nutrients and excrete waste, a process that must persist indefinitely to sustain life, even during sleep.
Cells exchange substances only with interstitial fluid in the vicinity, necessitating a continuous system for replenishing nutrients and maintaining waste disposal.
Function of the Cardiovascular System:
Major function: Transportation.
Major transport vehicle: Blood.
Carries essential substances: Oxygen, nutrients, cell wastes, hormones, and more for homeostasis.
Anatomy of the Heart
Size, Location, and Orientation
Physical Description: The heart is about the size of a human fist and weighs less than one pound. It is cone-shaped.
Location: Enclosed within the inferior mediastinum (middle section of the thoracic cavity) between the lungs.
Its apex points toward the left hip and rests on the diaphragm, around the fifth intercostal space, where stethoscopes are placed to check heart rates.
The broad base points toward the right shoulder, just beneath the second rib.
Coverings and Walls of the Heart
Pericardium Structure:
Composed of three layers
Fibrous Pericardium: Outermost layer providing protection and anchorage.
Serous Pericardium: Two-layered-
Parietal Layer: Lines the fibrous pericardium.
Visceral Layer (Epicardium): Encloses the heart wall.
Pericardial Cavity: Fills with lubricating serous fluid to minimize friction during heart beats.
Heart Wall Layers:
Epicardium: Also the visceral pericardium.
Myocardium: Thick layer of cardiac muscle responsible for contractions and linked by intercalated discs allowing ion flow between cells.
Endocardium: Thin layer lining the heart chambers, continuous with blood vessel linings.
Homeostatic Imbalances
Pericarditis: Inflammation, leading to decreased serous fluid, resulting in painful adhesions disrupting heart movements.
Heart Chambers and Associated Vessels
Components: Four chambers
Atria: Superior chambers, primarily receive blood.
Ventricles: Inferior, thick-walled chambers that pump blood out of the heart.
Path of Blood:
Blood flows from body veins into the atria and then to the ventricles. The ventricles contract and propel blood into circulation.
Circuits and Functionality
Double Pump System:
Right Side: Pumps oxygen-poor blood to the lungs (pulmonary circuit) via the superior and inferior vena cavae.
Left Side: Pumps oxygen-rich blood to the body (systemic circuit) via the aorta.
Pulmonary Circuit: Blood travels from the right ventricle to the lungs, where gas exchange occurs (oxygen intake and carbon dioxide removal) before returning to the left atrium.
Systemic Circuit: Oxygen-rich blood gets pumped from the left ventricle to body tissues, and oxygen-poor blood returns to the right atrium via systemic veins.
Structural Differences in Ventricles: The left ventricle possesses thicker walls due to the increased pressure required to pump blood throughout the body compared to the right ventricle.
Heart Valves
Types of Valves
Atrioventricular (AV) Valves:
Located between the atria and ventricles. Prevent backflow into the atria when ventricles contract.
Left AV Valve: Bicuspid (Mitral) Valve - two cusps.
Right AV Valve: Tricuspid Valve - three cusps.
Chordae Tendineae: Tendinous cords that anchor the valve cusps to the ventricular walls.
Semilunar Valves:
Located at the base of the arteries leaving the ventricles, comprising the pulmonary semilunar valve and the aortic semilunar valve. Each has three cusps.
Valve Functionality
AV Valve Operation:
Open during heart relaxation to permit blood flow.
Close when ventricles contract to prevent backflow.
Intraventricular Pressure Rise: Forces AV cusps upward, closing the valves.
Semilunar Valve Operation:
Open during ventricular contraction to allow blood to enter arteries.
Close during relaxation to prevent blood from reentering the heart.
Homeostatic Imbalances - Valve Function
Incompetent Valve: Allows backflow, causing inefficient circulation.
Valvular Stenosis: Stiff valve requiring more forceful contraction, increasing cardiac workload.
May lead to heart failure requiring valve replacement (mechanical, biological, or synthetic).
Cardiac Circulation
Coronary Arteries: Supply oxygen and nutrients to the heart muscles (myocardium).
Drainage: Cardiac veins empty into the coronary sinus, which drains into the right atrium.
Homeostatic Imbalances: Rapid heart rates can shorten blood supply to the myocardium, leading to Angina Pectoris (chest pain), which may escalate to Myocardial Infarction (heart attack).
An area may become infarcted when oxygen supply is insufficient, resulting in cell death.
Summary of Key Terms
Intercalated Discs: Junctions between myocardial cells that facilitate electrical impulses.
Chordae Tendineae: Tendinous cords that anchor AV valve cusps.
Coronary Sinus: Vessel collecting blood from cardiac veins to the right atrium.
Epicardium: The visceral layer of the pericardium, part of the heart wall.
Myocardial Infarction (MI): A heart attack caused by reduced blood flow to the heart.
Structural Relationships in the Heart
The location and orientation of the heart relative to surrounding organs and structures is crucial for understanding its anatomy and function. The effective arrangement of chambers and valves ensures adequate blood flow in a manner that supports both pulmonary and systemic circulation efficiently.
The Heart
Function of Major Anatomical Areas: The heart consists of four chambers: the atria (receiving blood) and ventricles (pumping blood). The right side handles oxygen-poor blood while the left side deals with oxygen-rich blood.
Pathway of Blood: Blood flows from body veins into the atria, then to the ventricles, before being pumped out to the lungs (right side) and the body (left side).
Pulmonary vs. Systemic Units: The pulmonary circuit carries blood to the lungs for oxygenation, while the systemic circuit delivers oxygenated blood to body tissues.
Function of Heart Valves: Prevent backflow into the atria and ventricles, ensuring one-way blood flow.
Functional Blood Supply: The coronary arteries supply oxygen and nutrients to the heart muscles.
Intrinsic Conduction System: Includes nodes (SA node, AV node) and pathways that facilitate impulse conduction, dictating heart rhythm.
Electrocardiogram (ECG): Provides information about heart rhythm and electrical activity.
Key Terms: Define systole, diastole, stroke volume, cardiac cycle, heart sounds, and heart murmur.
Vagus Nerve and Heart Rate: Stimulation of the vagus nerve slows heart rate, while exercise and epinephrine increase it.
Blood Vessels
Structure and Function: Differentiate among arteries, veins, and capillaries regarding their structure and roles in circulation.
Major Arteries and Veins: Identify the main vessels and the body regions they supply.
Pulse: Define and list several pulse points throughout the body.
Blood Pressure: Factors affecting blood pressure and its significance for health.
Hypertension and Atherosclerosis: Definitions and potential health risks associated with each condition.
Capillary Exchange: Describe the mechanism by which oxygen, nutrients, and waste are exchanged across capillary walls.
Chapter 11: The Cardiovascular System
The Heart's Conduction System
Intrinsic Conduction System:
A unique system responsible for regulating the heart's rhythm.
Composed of special tissue that resembles both muscular and nervous tissue, allowing for spontaneous contractions.
Key Components:
Sinoatrial (SA) Node:
Located in the right atrium; acts as the heart's "pacemaker".
Initiates each heartbeat and sets the basic rhythm, conducting impulses at a rate of approximately 75 depolarizations per minute.
Atrioventricular (AV) Node:
Located at the junction of the atria and ventricles.
Delays the impulse after it passes from the atria to allow complete contraction of the atria.
AV Bundle (Bundle of His):
Pathway that transmits impulses from the AV node to the bundle branches.
Bundle Branches:
Located in the interventricular septum and conduct impulses towards the ventricles.
Purkinje Fibers:
Spread throughout the ventricular myocardium, leading to coordinated contraction of ventricles.
Physiology of the Heart
Primary Function:
Pumps blood continuously through the body; performs approximately 6,000 quarts (about 1500 gallons) of work per day.
Cardiac Muscle Property:
Spontaneous contraction ability; can beat independently from nerve impulses, unlike skeletal muscle cells.
Importance of Heart Valves:
Prevent backflow of blood within the heart chambers.
Critical for maintaining the efficiency of the pumping action.
Heart Rhythmic Activity
Atrial Cells vs. Ventricular Cells:
Atrial cells generally contract at about 60 beats per minute, while ventricular cells contract at 20-40 beats per minute.
Conduction Pathway
Impulse Travel:
The depolarization wave moves from the SA node to the AV node, then through the AV bundle, right and left bundle branches, and finally to the Purkinje fibers, resulting in contraction.
Electrocardiogram (ECG) Insights
Information Obtained:
Can detect abnormalities in heart rhythm and electrical activity, potentially indicating damage (e.g., myocardial infarction).
Heart Rate Regulation
Autonomic Nervous System Regulation:
Acts similarly to gas pedals and brakes to adjust the heart rate.
Factors Influencing Heart Rate:
Stimulation of the Vagus Nerve:
Slows heart rate during non-crisis times.
Exercise:
Increases heart rate due to higher oxygen demands.
Hormones (e.g., Epinephrine):
Increase heart rate and contractility.
Ions:
Alter heart activity based on levels of sodium, potassium, calcium, etc.
Cardiac Cycle
Definition:
Events that occur during one complete heartbeat: contraction (systole) and relaxation (diastole).
Average heart rate leads to a cardiac cycle of about 0.8 seconds.
Phases of the Cardiac Cycle:
Atrial Diastole (Ventricular Filling):
Heart is relaxed, AV valves open, blood passively flows into ventricles.
Atrial Systole:
Atria contract, filling ventricles completely.
Isovolumetric Contraction:
Atria relax, ventricles contract with all valves closed.
Ventricular Systole (Ejection Phase):
Ventricles contract; pressure exceeds that in arteries, and blood is ejected.
Isovolumetric Relaxation:
Ventricles relax; all valves are closed momentarily.
Heart Sounds
Sounds Described:
"Lub" (first sound from AV valve closure) and "Dup" (second sound from semilunar valve closure).
Heart Murmurs:
Result from turbulent blood flow; can be normal in children or indicate issues in adults.
Cardiac Output (CO)
Definition:
Volume of blood pumped from each ventricle per minute: CO = HR × SV.
Normal resting CO = 5.25 L/min (based on HR of 75 bpm and SV of 70 mL).
Factors Affecting Stroke Volume:
Preload:
Amount of stretch of cardiac muscle before contraction; influenced by venous return.
Contractility:
Strength of ventricular contraction, affected by calcium, sympathetic stimulation, etc.
Afterload:
Pressure the ventricles must overcome to eject blood.
Homeostatic Imbalance: Congestive Heart Failure (CHF)
Definition:
Condition where heart's pumping efficiency decreases, failing to meet tissue needs.
Symptoms:
Left heart failure leads to pulmonary congestion; right failure leads to peripheral congestion.
Treatment:
Digitalis may be administered to enhance contractility and stroke volume.
Blood Vessels
Structure and Function:
Arteries carry blood away from the heart; veins return blood to the heart; capillaries provide exchange between blood and tissues.
Circulatory System Concept:
Blood circulates through a closed system with continuous movement (first described by William Harvey).
Ch. 11: The Cardiovascular System
11.1 The Heart
Identify and describe the function of the major anatomical areas of the heart.
Trace the pathway of blood through the heart.
Compare and contrast the pulmonary and systemic units.
Describe the function of the heart valves.
Name the functional blood supply of the heart.
Name the elements of the heart's intrinsic conduction system and describe the pathway of impulses through this system.
Explain what information an electrocardiogram provides.
Define systole, diastole, stroke volume, cardiac cycle, heart sounds, and heart murmur.
Describe how stimulation of the vagus nerve, exercise, epinephrine, and/or various ions affects the heart rate.
11.2 Blood Vessels
Compare and contrast the structure and function of arteries, veins, and capillaries.
Identify the major arteries and veins along with the major body region supplied by each.
Define pulse, and list several pulse points.
Define blood pressure and list factors that affect and determine blood pressure.
Define hypertension and atherosclerosis and describe possible health conditions for each.
Describe the exchange that occurs across capillary walls.
Chapter 11: The Cardiovascular System
11.1 Heart Rate and Regulation
Average heart rates:
Females: 72-80 beats per minute
Males: 64-72 beats per minute
Factors influencing heart rate:
Heat: Increases heart rate by boosting metabolic rate of heart cells, causing phenomena such as
Rapid heartbeat during fever due to increased metabolic demand.
Exercise generates heat, which similarly affects heart rate.
Cold: Decreases heart rate directly.
Exercise:
Increases heart rate via sympathetic nervous system controls.
Increases stroke volume through muscular pump action.
11.1 Homeostatic Imbalance
Congestive Heart Failure (CHF):
Characterized by reduced heart pumping efficiency leading to inadequate circulation.
Caused by:
Coronary Atherosclerosis: Clogging of coronary vessels with fatty build-up.
Hypertensive Heart Disease: Increased heart workload due to high blood pressure.
Myocardial Infarctions: Events leading to non-contracting scar tissue formation.
Result:
Lower stroke volume due to weak contractions, treated with digitalis to enhance contractility and cardiac output.
Potential Failures:
Left Heart Failure:
Leads to pulmonary congestion as blood backs up into the lungs.
Symptoms: Pulmonary edema from increased lung pressure causing fluid leakage into lung tissue.
Right Heart Failure:
Causes peripheral congestion with blood backing up into systemic circulation.
Symptoms: Edema in distal extremities, swelling in feet, ankles, and fingers.
Overall heart failure may occur as one side failing strains the other.
11.2 Blood Vessels
11.2a Structure and Function of Blood Vessels
Vascular System: Closed transport system for blood circulation.
Components:
Arteries: Carry blood away from the heart.
Veins: Drain tissues and return blood to the heart.
Capillaries: Connection between arteries and veins, facilitating exchange between blood and body tissues.
11.2b Comparison of Blood Vessel Structures
Microscopic Anatomy:
Arteries have three layers (tunics):
Tunica Intima:
Inner layer made of endothelium and connective tissue.
Provides a slick surface to decrease friction.
Tunica Media:
Middle layer consisting of smooth muscle and elastic fibers, thicker in arteries.
Responsible for adjusting vessel diameter, influencing blood pressure.
Tunica Externa:
Outer layer made of fibrous connective tissue that supports and protects vessels.
Structural Differences:
Arteries: Thicker walls, especially tunica media for robust blood flow management.
Veins: Thinner walls; larger lumen, have valves to prevent backflow due to low blood pressure and gravity.
Capillaries: One-cell thick walls allowing exchange of substances.
11.2c Capillary Beds and Blood Flow
Capillary Function:
Microcirculation refers to blood flow through capillary beds, with blood flow controlled by the constriction of arterioles.
Precapillary Sphincters: Control blood flow into capillaries; can redirect flow through shunts.
11.2d Varicose Veins
Caused by prolonged standing or obesity; results in twisted veins and can lead to thrombophlebitis, a dangerous condition where blood clots form.
11.2e Gross Anatomy of Blood Vessels
Major Arteries of Systemic Circulation
Aorta:
Largest artery, branches, and their functions:
Ascending Aorta: Supplies the coronary arteries.
Aortic Arch:
Branches: Brachiocephalic trunk (branches into R. common carotid and R. subclavian arteries), L. common carotid artery, L. subclavian artery.
Thoracic Aorta: Supplies intercostal muscles, lungs, esophagus, and diaphragm.
Abdominal Aorta: Supplies celiac trunk, renal arteries, gonadal arteries, lumbar arteries, and inferior mesenteric artery.
Major Veins of Systemic Circulation
Veins Draining into Superior Vena Cava:
Includes radial, ulnar, basilic, cephalic, vertebral, and internal jugular veins.
Veins Draining into Inferior Vena Cava:
Includes anterior tibial, posterior tibial, fibular veins, and great saphenous veins, leading to common iliac veins.
11.3 Physiology of Circulation
Blood Pressure
Definition: Pressure blood exerts against vessel walls; crucial for maintaining circulation.
Blood Pressure Measurements:
Expressed in mm Hg, with systolic pressure over diastolic pressure (e.g., 120/80 mm Hg).
Measured using the auscultatory method at the brachial artery.
Influences on Blood Pressure:
Cardiac output (CO) and peripheral resistance (PR) determined by the formula:
Factors Increasing BP: Exercise, vasoconstriction from sympathetic nervous system, blood volume, and viscosity.
Capillary Exchange
Mechanisms for substance exchange:
Direct diffusion (lipid-soluble gases).
Diffusion through intercellular clefts (fluid and small solutes).
Diffusion through pores (fenestrated capillaries).
Transport via vesicles (for lipid-insoluble substances).
11.3 Developmental Aspects of the Cardiovascular System
Fetal Shunts: Modifications to the circulatory system for fetal circulation function prior to birth.
Aging Effects: Cardiovascular modifications over time and strategies to maintain heart health.
Summary
Each aspect of the cardiovascular system is crucial for maintaining homeostasis, ensuring adequate blood circulation, and adapting to body demands through complex regulatory mechanisms.
Ch. 11.1 The Heart
Identify and describe the function of the major anatomical areas of the heart.
Trace the pathway of blood through the heart.
Compare and contrast the pulmonary and systemic units.
Describe the function of the heart valves.
Name the functional blood supply of the heart.
Name the elements of the heart's intrinsic conduction system, and describe the pathway of impulses through this system.
Explain what information an electrocardiogram provides.
Define systole, diastole, stroke volume, cardiac cycle, heart sounds, and heart murmur.
Describe how stimulation of the vagus nerve, exercise, epinephrine, and/or various ions affects the heart rate.
Ch. 11.2 Blood Vessels
Compare and contrast the structure and function of arteries, veins, and capillaries.
Identify the major arteries and veins along with the major body region supplied by each.
Define pulse, and list several pulse points.
Define blood pressure and list factors that affect and determine blood pressure.
Define hypertension and atherosclerosis, and describe possible health conditions for each.
Describe the exchange that occurs across capillary walls.
Additional Notes from the Cardiovascular System:
Average heart rates are typically between 72-80 beats per minute for females and 64-72 for males.
Factors affecting heart rate include heat, cold, and exercise, which influences the sympathetic nervous system and stroke volume.
Congestive Heart Failure (CHF) refers to reduced heart pumping efficiency leading to inadequate circulation, possibly caused by coronary atherosclerosis or hypertensive heart disease.
Blood pressure is defined as the pressure blood exerts against vessel walls and is vital for maintaining circulation.
Ch. 11.1 The Heart
Identify and describe the function of the major anatomical areas of the heart:
Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cavae.
Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary arteries.
Left Atrium: Receives oxygenated blood from the lungs via the pulmonary veins.
Left Ventricle: Pumps oxygenated blood to the body through the aorta.
Trace the pathway of blood through the heart:
Body → 2. Superior/Inferior Vena Cavae → 3. Right Atrium → 4. Tricuspid Valve → 5. Right Ventricle → 6. Pulmonary Valve → 7. Pulmonary Arteries → 8. Lungs → 9. Pulmonary Veins → 10. Left Atrium → 11. Mitral Valve → 12. Left Ventricle → 13. Aortic Valve → 14. Aorta → 15. Body
Compare and contrast the pulmonary and systemic units:
Pulmonary Circuit:
Transports deoxygenated blood from the right Ventricle to the lungs to gain oxygen, then returns oxygenated blood to the left atrium.
Systemic Circuit:
Transports oxygenated blood from the left ventricle to the rest of the body and returns deoxygenated blood to the right atrium.
Describe the function of the heart valves:
Atrioventricular Valves (Tricuspid and Mitral): Prevent backflow of blood into the atria during ventricular contraction.
Semilunar Valves (Pulmonary and Aortic): Prevent backflow into the ventricles after contraction.
Name the functional blood supply of the heart:
Coronary Arteries: Supply blood to heart muscle.
Cardiac Veins: Drain deoxygenated blood from the heart muscle into the right atrium via the coronary sinus.
Name the elements of the heart's intrinsic conduction system:
Sinoatrial (SA) Node: Primary pacemaker setting the heart rate.
Atrioventricular (AV) Node: Delays impulse before it passes to ventricles.
Bundle of His: Carries impulses to the ventricles.
Purkinje Fibers: Distribute impulses throughout ventricles for contraction.
Explain what information an electrocardiogram provides:
Measures electrical activity of the heart, showing heart rate, rhythm, and issues such as arrhythmias or myocardial infarctions (heart attacks).
Define systole, diastole, stroke volume, cardiac cycle, heart sounds, and heart murmur:
Systole: Phase when the heart muscle contracts.
Diastole: Phase when the heart muscle relaxes.
Stroke Volume: Amount of blood pumped by each ventricle during a contraction.
Cardiac Cycle: Complete sequence of heart contraction and relaxation.
Heart Sounds: Sounds produced by valves closing.
Heart Murmur: Abnormal sound indicating turbulent blood flow.
Describe how stimulation of the vagus nerve, exercise, epinephrine, and/or various ions affects the heart rate:
Vagus Nerve Stimulation: Lowers heart rate (parasympathetic).
Exercise: Increases heart rate (sympathetic).
Epinephrine: Increases heart rate and cardiac output during stress.
Various Ions (e.g., potassium, calcium): High potassium can decrease heart rate; calcium can enhance contraction strength.
Ch. 11.2 Blood Vessels
Compare and contrast the structure and function of arteries, veins, and capillaries:
Arteries: Thick, elastic walls; carry oxygenated blood away from the heart, withstand high pressure.
Veins: Thinner walls, larger lumen; carry deoxygenated blood back to the heart, have valves to prevent backflow.
Capillaries: One cell thick; facilitate gas and nutrient exchange between blood and tissues.
Identify the major arteries and veins along with the major body region supplied by each:
Aorta: Supplies the entire body.
Coronary Arteries: Supply the heart muscle.
Carotid Arteries: Supply the head and neck.
Femoral Artery: Supplies the thigh and leg.
Jugular Veins: Drain head and neck into superior vena cava.
Femoral Vein: Drains the leg into inferior vena cava.
Define pulse and list several pulse points:
Pulse: Expansion and recoil of arteries with each heartbeat.
Pulse Points:
Carotid (neck)
Radial (wrist)
Femoral (groin)
Popliteal (behind knee)
Dorsalis pedis (top of foot).
Define blood pressure and list factors that affect and determine blood pressure:
Blood Pressure: The force of blood against vessel walls.
Factors: Cardiac output, blood volume, vascular resistance, viscosity, and elasticity of arteries.
Define hypertension and atherosclerosis and describe possible health conditions for each:
Hypertension: Persistently high blood pressure; can lead to heart disease, stroke, and kidney damage.
Atherosclerosis: Buildup of fatty deposits in artery walls; can lead to coronary artery disease, heart attacks, and strokes.
Describe the exchange that occurs across capillary walls:
Exchange of oxygen, carbon dioxide, nutrients, and waste products occurs through diffusion, osmosis, and filtration due to concentration gradients and pressure differences.
The Respiratory System
Overview
The respiratory system serves three primary functions:
Provides oxygen to the body
Removes carbon dioxide
Helps regulate blood pH
Critical Importance:
Oxygen is essential for cellular function; cells cannot survive without it for extended periods.
Accumulation of carbon dioxide leads to acidification of blood, adversely affecting cell performance.
Anatomy of the Respiratory System
13.1 Functional Anatomy of the Respiratory System
Learning Objectives:
Identify and name organs along the respiratory passageway from the nasal cavity to alveoli.
Describe protective mechanisms inherent in the respiratory system.
Respiratory Organs
The respiratory system is composed of:
Nose
Pharynx
Larynx
Trachea
Bronchi (including primary bronchi and their branches)
Lungs (which contain alveoli)
Air Passageways:
The upper respiratory tract comprises the passageways from the nose to the larynx.
The lower respiratory tract includes the structures from the trachea to the alveoli.
Function of Conducting Passageways:
Purify, humidify, and warm the air before it reaches the alveoli to ensure fewer irritants reach the lungs.
13.1a The Nose
Nasal Structure:
The nose is the visible part of the respiratory system.
Air enters through the nostrils (nares) and passes into the nasal cavity.
The nasal cavity is divided by the nasal septum into right and left halves.
Olfactory receptors are located within the thin mucosa in the superior nasal cavity.
Respiratory Mucosa:
The lining of the nasal cavity consists of respiratory mucosa that warms air and traps foreign particles.
Ciliated cells move mucus towards the throat for swallowing and digestion.
Cold temperatures can slow cilia action, leading to a runny nose.
Conchae:
Lateral walls feature conchae that enhance air turbulence and surface area, trapping inhaled particles.
Palate:
Divides the nasal and oral cavities. Comprises the hard palate (anterior, bony) and soft palate (posterior, unsupported).
Paranasal Sinuses:
Located within frontal, sphenoid, ethmoid, and maxillary bones.
Lessen skull weight, contribute to voice resonance, and produce mucus that drains into the nasal cavity.
Homeostatic Imbalances:
Cleft Palate: Birth defect leads to respiratory and oral difficulties.
Rhinitis: Inflammation of nasal mucosa due to infections or allergens, leading to nasal congestion.
Sinusitis: Inflammation of sinuses affecting voice quality.
13.1b The Pharynx
The pharynx (throat) is approximately 13 cm (5 inches) long.
Divided into three regions:
Nasopharynx: Air passes from nasal cavity to oropharynx here.
Oropharynx: Common passageway for air and food.
Laryngopharynx: Underneath larynx, conducting air to the larynx.
Epiglottis: Flap directing food to the esophagus and preventing it from entering the larynx.
Tonsils:
Lymphatic tissues (pharyngeal, palatine, and lingual tonsils) are important for protecting against infection.
Homeostatic Imbalances:
Tonsillitis: Can lead to the swelling of tonsils and obstruct nasopharynx.
13.1c The Larynx
The larynx (voice box) routes air and food correctly and is involved in speech.
Made up of hyaline cartilages and elastic cartilage (epiglottis).
Thyroid cartilage: Forms the Adam’s apple.
The epiglottis: Prevents food from entering the larynx.
Vocal Folds: Positioned within the larynx, enable sound production via their vibration as air passes.
13.1d The Trachea
The trachea (windpipe) measures 10-12 cm long, leading from the larynx to the bronchi.
Composed of C-shaped cartilage rings ensuring it remains open.
The trachealis muscle allows trachea to contract during swallowing.
Homeostatic Imbalances:
Tracheal obstruction is life-threatening; choking can cause suffocation. - Heimlich maneuver is often employed in emergencies.
13.1e The Main Bronchi
The right main bronchus is broader and straighter than the left, making it more likely for foreign objects to become lodged.
13.1f The Lungs
The lungs occupy most of the thoracic cavity.
Each lung is covered by visceral pleura (pleural coverings) and is divided into lobes (left lung has 2 lobes; right lung has 3).
Pleural Membrane Function:
Provide lubrication allowing the lung movement during respiration.
13.2 Respiratory Physiology
Learning Objectives:
Define terms such as cellular respiration, external and internal respiration, pulmonary ventilation, expiration, and inspiration.
Respiration Processes
Pulmonary Ventilation: Movement of air into and out of lungs (breathing).
External Respiration: Gas exchange (oxygens and carbon dioxide) between alveoli and pulmonary blood.
Respiratory Gas Transport: Movement of oxygen and carbon dioxide within the bloodstream.
Internal Respiration: Gas exchange between systemic blood and body tissues.
Mechanics of Breathing
Inspiration:
Involves contraction of diaphragm and external intercostals, increasing thoracic cavity volume leading to negative pressure, drawing air into lungs.
Expiration: Techniques largely involve elasticity of lungs; air is expelled passively as lung volume decreases.
Forced Expiration: When diseased, internal intercostal muscles and abdominal muscles are engaged to help expel air forcefully.
Respiratory Volumes and Capacities
Tidal Volume (TV): Normal air volume exchanged during quiet breathing (approx. 500 ml).
Inspiratory Reserve Volume (IRV): Maximum additional air inhaled after tidal volume (approx. 3,100 ml).
Expiratory Reserve Volume (ERV): Maximum air exhaled forcibly after normal expiration (approx. 1,200 ml).
Residual Volume: Air remaining post-maximal expiration (approx. 1,200 ml).
Vital Capacity (VC): Total air exchanged (TV + IRV + ERV, approximately 4,800 ml in males).
Dead Space Volume: Portion of air that does not reach alveoli (approximately 150 ml).
Functional Volume: Air successfully leading to gas exchange (~350 ml).
Conclusion
The respiratory system and its components play crucial roles in ventilation and gas exchange within the body, essential for maintaining cellular functions and overall metabolic processes.
The Respiratory System
Overview
The respiratory system serves three primary functions:
Provides oxygen to the body
Removes carbon dioxide
Helps regulate blood pH
Critical Importance:
Oxygen is essential for cellular function; cells cannot survive without it for extended periods.
Accumulation of carbon dioxide leads to acidification of blood, adversely affecting cell performance.
Anatomy of the Respiratory System
13.1 Functional Anatomy of the Respiratory System
Learning Objectives:
Identify and name organs along the respiratory passageway from the nasal cavity to alveoli.
Describe protective mechanisms inherent in the respiratory system.
Respiratory Organs
The respiratory system is composed of:
Nose
Pharynx
Larynx
Trachea
Bronchi (including primary bronchi and their branches)
Lungs (which contain alveoli)
Air Passageways:
The upper respiratory tract comprises the passageways from the nose to the larynx.
The lower respiratory tract includes the structures from the trachea to the alveoli.
Function of Conducting Passageways:
Purify, humidify, and warm the air before it reaches the alveoli to ensure fewer irritants reach the lungs.
13.1a The Nose
Nasal Structure:
The nose is the visible part of the respiratory system.
Air enters through the nostrils (nares) and passes into the nasal cavity.
The nasal cavity is divided by the nasal septum into right and left halves.
Olfactory receptors are located within the thin mucosa in the superior nasal cavity.
Respiratory Mucosa:
The lining of the nasal cavity consists of respiratory mucosa that warms air and traps foreign particles.
Ciliated cells move mucus towards the throat for swallowing and digestion.
Cold temperatures can slow cilia action, leading to a runny nose.
Conchae:
Lateral walls feature conchae that enhance air turbulence and surface area, trapping inhaled particles.
Palate:
Divides the nasal and oral cavities. Comprises the hard palate (anterior, bony) and soft palate (posterior, unsupported).
Paranasal Sinuses:
Located within frontal, sphenoid, ethmoid, and maxillary bones.
Lessen skull weight, contribute to voice resonance, and produce mucus that drains into the nasal cavity.
Homeostatic Imbalances:
Cleft Palate: Birth defect leads to respiratory and oral difficulties.
Rhinitis: Inflammation of nasal mucosa due to infections or allergens, leading to nasal congestion.
Sinusitis: Inflammation of sinuses affecting voice quality.
13.1b The Pharynx
The pharynx (throat) is approximately 13 cm (5 inches) long.
Divided into three regions:
Nasopharynx: Air passes from nasal cavity to oropharynx here.
Oropharynx: Common passageway for air and food.
Laryngopharynx: Underneath larynx, conducting air to the larynx.
Epiglottis: Flap directing food to the esophagus and preventing it from entering the larynx.
Tonsils:
Lymphatic tissues (pharyngeal, palatine, and lingual tonsils) are important for protecting against infection.
Homeostatic Imbalances:
Tonsillitis: Can lead to the swelling of tonsils and obstruct nasopharynx.
13.1c The Larynx
The larynx (voice box) routes air and food correctly and is involved in speech.
Made up of hyaline cartilages and elastic cartilage (epiglottis).
Thyroid cartilage: Forms the Adam’s apple.
The epiglottis: Prevents food from entering the larynx.
Vocal Folds: Positioned within the larynx, enable sound production via their vibration as air passes.
13.1d The Trachea
The trachea (windpipe) measures 10-12 cm long, leading from the larynx to the bronchi.
Composed of C-shaped cartilage rings ensuring it remains open.
The trachealis muscle allows trachea to contract during swallowing.
Homeostatic Imbalances:
Tracheal obstruction is life-threatening; choking can cause suffocation. - Heimlich maneuver is often employed in emergencies.
13.1e The Main Bronchi
The right main bronchus is broader and straighter than the left, making it more likely for foreign objects to become lodged.
13.1f The Lungs
The lungs occupy most of the thoracic cavity.
Each lung is covered by visceral pleura (pleural coverings) and is divided into lobes (left lung has 2 lobes; right lung has 3).
Pleural Membrane Function:
Provide lubrication allowing the lung movement during respiration.
13.2 Respiratory Physiology
Learning Objectives:
Define terms such as cellular respiration, external and internal respiration, pulmonary ventilation, expiration, and inspiration.
Respiration Processes
Pulmonary Ventilation: Movement of air into and out of lungs (breathing).
External Respiration: Gas exchange (oxygens and carbon dioxide) between alveoli and pulmonary blood.
Respiratory Gas Transport: Movement of oxygen and carbon dioxide within the bloodstream.
Internal Respiration: Gas exchange between systemic blood and body tissues.
Mechanics of Breathing
Inspiration:
Involves contraction of diaphragm and external intercostals, increasing thoracic cavity volume leading to negative pressure, drawing air into lungs.
Expiration: Techniques largely involve elasticity of lungs; air is expelled passively as lung volume decreases.
Forced Expiration: When diseased, internal intercostal muscles and abdominal muscles are engaged to help expel air forcefully.
Respiratory Volumes and Capacities
Tidal Volume (TV): Normal air volume exchanged during quiet breathing (approx. 500 ml).
Inspiratory Reserve Volume (IRV): Maximum additional air inhaled after tidal volume (approx. 3,100 ml).
Expiratory Reserve Volume (ERV): Maximum air exhaled forcibly after normal expiration (approx. 1,200 ml).
Residual Volume: Air remaining post-maximal expiration (approx. 1,200 ml).
Vital Capacity (VC): Total air exchanged (TV + IRV + ERV, approximately 4,800 ml in males).
Dead Space Volume: Portion of air that does not reach alveoli (approximately 150 ml).
Functional Volume: Air successfully leading to gas exchange (~350 ml).
Conclusion
The respiratory system and its components play crucial roles in ventilation and gas exchange within the body, essential for maintaining cellular functions and overall metabolic processes.