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Lina Le Period 6 Cardiovascular System - Coggle Diagram
Lina Le Period 6 Cardiovascular System
ABO, Rh blood types
ABO blood groups
Based on presence or absence of two agglutinogens (A and B) on surface of RBCs
Blood may contain preformed anti-A or anti-B antibodies (agglutinins)
Vital Signs
Arterial Blood pressure
Systemic arterial BP is measured indirectly by auscultatory methods using a sphygmomanometer
Pressure is released slowly, and examiner listens for sounds of
Korotkoff with a stethoscope
Increase pressure in cuff until it exceeds systolic pressure in brachial artery
Wrap cuff around arm superior to elbow
Systolic pressure: normally less than 120 mm Hg
Pressure when sounds first occur as blood starts to spurt through artery
Diastolic pressure: normally less than 80 mm Hg
Pressure when sounds disappear because artery no longer constricted; blood flowing freely
Respiratory Rate
Pulse
Radial pulse (taken at the wrist): most routinely used, but there are other clinically important pulse points
Pressure points: areas where arteries are close to body surface
Can be compressed to stop blood flow in event of hemorrhaging
Body Temperature
Venous Blood Pressure
Changes little during cardiac cycle
Low pressure of venous side requires adaptations to help with venous return
Factors aiding venous return
Respiratory pump: pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand
Sympathetic venoconstriction: under sympathetic control, smooth muscles constrict, pushing blood back toward heart
Muscular pump: contraction of skeletal muscles “milks” blood back toward heart;valves prevent backflow
Anatomy of the Heart
Surface features
Coronary sulcus (atrioventricular groove)
Anterior interventricular sulcus
Anterior position of interventricular septum
To identify that it is the anterior interventricular sulcus, it will be diagonal/ at an angle
Posterior interventricular sulcus
Landmark on posteroinferior surface
To identify that it is the posterior interventricular sulcus, it will be vertical
Internal features
Interatrial septum : separates atria
Interventricular septum: separates ventricles
Four chambers
Left and right ventricles
Make up most of the volume of heart
Right ventricle: most of anterior surface
Left ventricle: posteroinferior surface
Trabeculae carneae: irregular ridges of muscle on ventricular walls
Papillary muscles: project into ventricular cavity
Anchor chordae tendineae that are attached to heart valves
Thicker walls than atria
Actual pumps of heart
Right ventricle: Pumps blood into pulmonary trunk
Left ventricle: Pumps blood into aorta (largest artery in body)
Left and right atria
Atria: the receiving chambers
Small, thin-walled chambers; contribute little to propulsion of blood
Auricles: appendages that increase atrial volume
Right atrium: receives deoxygenated blood from body
Three veins empty into right atrium:
Inferior vena cava: returns blood from body regions below the diaphragm
Superior vena cava: returns blood from body regions above the diaphragm
Coronary sinus: returns blood from coronary veins
Left atrium: receives oxygenated blood from lungs
Heart Valves
Ensure unidirectional (one way) blood flow through heart – prevents backflow of blood
Open and close in response to pressure changes
Two major types of valves
Atrioventricular valves located between atria and ventricles
Tricuspid valve (right AV valve): made up of three cusps and lies between right atria and ventricle
Mitral valve (left AV valve, bicuspid valve): made up of two cusps and lies between left atria and ventricle
Chordae tendineae: anchor cusps of AV valves to papillary muscles that function to:
Hold valve flaps in closed position
Prevent flaps from everting back into atria
Semilunar valves located between ventricles and major arteries
Two semilunar (SL) valves prevent backflow from major arteries back into ventricles
Open and close in response to pressure changes
– Each valve consists of three cusps that roughly resemble a half moon
– Pulmonary semilunar valve: located between right ventricle and pulmonary trunk
– Aortic semilunar valve: located between left ventricle and aorta
Major Functions of the Cardiovascular System
Brings oxygen and nurtients to every cell in the body
Removes wastes like carbon dioxide
protects the body from disease/ clotting open wounds
regulating body temperature
Blood Flow through the Heart and Body
Right side of the heart
Superior vena cava (SVC), inferior vena cava (IVC), and coronary sinus →
Right atrium →
Tricuspid valve →
Right ventricle →
Pulmonary semilunar valve →
Pulmonary trunk →
Pulmonary arteries →
Lungs
Left side of the heart
Four pulmonary veins →
Left atrium →
Mitral valve →
Left ventricle →
Aortic semilunar valve →
Aorta →
Systemic circulation
Disorders of the Cardiovascular System
Blood Disorder
Anemia
Blood has abnormally low O2-carrying capacity that is too low to support normal metabolism
Sign of problem rather than disease itself
Symptoms: fatigue, pallor, dyspnea, and chills
Three groups based on cause: blood loss, not enough production of RBCs, too many RBCs being destroyed
Blood loss
Hemorrhagic anemia
Rapid blood loss
Treated by blood replacement
Chronic hemorrhagic anemia
Slight but persistent blood loss
Primary problem must be treated to stop blood loss
Not enough production of RBCs
Iron-deficiency anemia
May be caused by hemorrhagic anemia, and/or low iron intake or impaired absorption
Treatment: iron supplements
Too many RBCs being detroyed
Thalassemias
Typically found in people of Mediterranean ancestry
One globin chain is absent or faulty
RBCs are thin, delicate, and deficient in hemoglobin
Many subtypes that range in severity from mild to extremely severe
If very severe, monthly blood transfusions may be required
Sickle-cell anemia
mutated hemogloblin
RBCs become crescent shaped when O2 levels are low
Misshaped RBCs rupture easily and block small vessels
Results in poor O2 delivery and pain
Prevalent in black people of the African malarial belt and their
descendants
Possible benefit: people with sickle cell do not contract malaria
Kills 1 million each year
• Individuals with two copies of Hb-S can develop sickle-cell anemia
• Individuals with only one copy have milder disease and better chance of surviving malaria
Treatment: acute crisis treated with transfusions; inhaled nitric oxide
Leukocyte Disorders
Overproduction of abnormal WBC
Leukemias
Treatments: irradiation, antileukemic drugs; stem cell transplants
Death is usually from internal hemorrhage or overwhelming infections
Cancerous cells fill red bone marrow, crowding out other cell lines
Leads to anemia and bleeding
Immature, nonfunctional WBCs flood bloodstream
Without treatment, all leukemias are fatal
Named according to abnormal WBC clone involved
Myeloid leukemia involves myeloblast descendants
Lymphocytic leukemia involves lymphocytes
Cancerous condition involving overproduction of abnormal WBCs
Usually involve clones of single abnormal cell
Infectious mononucleosis
Highly contagious viral disease (“kissing disease”)
Usually seen in young adults
Caused by Epstein-Barr virus
Results in high numbers of typical agranulocytes
Involve lymphocytes that become enlarged
Symptoms:Tired, achy, chronic sore throat, low fever
Runs course with rest in 4–6 weeks
Abnormally low WBC count
Leukopenia
may be drug induced; particularly by anticancer drugs or glucocrticoids
Disorders of Hemostasis
Thromboembolic disorders: result in undesirable clot formation
Anticoagulant drugs: used to prevent undesirable clotting
Heparin: used clinically for pre- and postoperative cardiac care as well as to prevent venous thrombosis
Warfarin and direct oral anticoagulants: reduce risk of stroke in patients prone to atrial fibrillation in which blood pools in heart
Aspirin: antiprostaglandin that inhibits thromboxane A2; lowers heart attack incidence by 50%
Bleeding disorders: abnormalities that prevent normal clot formation
Hemophilia
Includes several similar hereditary bleeding disorders
Symptoms include prolonged bleeding, especially into joint cavities
Treatment: injections of genetically engineered factors; has eliminated need for plasma transfusion and risk of contracting hepatitis or HIV
Pericarditis
Inflammation of pericardium
Cardiac tamponade
Excess fluid that leaks into pericardial space
Can compress heart’s pumping ability
Treatment: fluid is drawn out of cavity (usually with syringe)
Angina pectoris
Thoracic pain caused by fleeting deficiency in blood delivery to myocardium
Cells are weakened
Myocardial infarction (heart attack)
Areas of cell death are repaired with noncontractile scar tissue
Prolonged coronary blockage
Defects in intrinsic conduction system may cause:
Arrhythmias: irregular heart rhythms
Uncoordinated atrial and ventricular contractions
Fibrillation: rapid, irregular contractions
Heart becomes useless for pumping blood, causing circulation to cease; may result in brain death
Treatment: defibrillation interrupts chaotic twitching, giving heart “clean slate” to start regular, normal depolarizations
Heart murmurs: abnormal heart sounds heard when blood hits obstructions
Usually indicates valve problems
Incompetent (or insufficient) valve: fails to close completely, allowing backflow of blood
Causes swishing sound as blood regurgitates backward from ventricle into atria
Stenotic valve: fails to open completely, restricting blood flow through valve
Causes high-pitched sound or clicking as blood is forced through narrow valve
Tachycardia: abnormally fast heart rate (>100 beats/min)
If persistent, may lead to fibrillation
Bradycardia: heart rate slower than 60 beats/min
May result in grossly inadequate blood circulation in nonathletes
May be desirable result of endurance training
Congestive heart failure (CHF)
Progressive condition; CO is so low that blood circulation is inadequate to meet tissue needs
Reflects weakened myocardium caused by:
Persistent high blood pressure: aortic pressure 90 mmHg causes myocardium to exert more force
Chronic increased ESV causes myocardium hypertrophy and weakness
Multiple myocardial infarcts: heart becomes weak as contractile cells are replaced with scar tissue
Coronary atherosclerosis: clogged arteries caused by fat buildup; impairs oxygen delivery to cardiac cells
Heart becomes hypoxic, contracts inefficiently
Dilated cardiomyopathy (DCM): ventricles stretch and become flabby, and myocardium deteriorates
Drug toxicity or chronic inflammation may play a role
Varicose veins : dilated and painful veins due to incompetent (leaky) valves
Factors that contribute include heredity and conditions that hinder venous return
Elevated venous pressure can cause varicose veins
Hypertension
Prehypertension if values elevated but not yet in hypertension range
May be transient adaptations during fever, physical exertion, and emotional upset
Often persistent in obese people
Prolonged hypertension is major cause of heart failure, vascular disease, renal failure, and stroke
Also accelerates atherosclerosis
Heart must work harder; myocardium enlarges, weakens, and becomes flabby
Sustained elevated arterial pressure of 140/90 mm Hg or higher
Hypotension
Low blood pressure below 90/60 mm Hg
Usually not a concern unless it causes inadequate blood flow to tissues
Often associated with long life and lack of cardiovascular illness
Circulatory shock
Condition where blood vessels inadequately fill and cannot circulate blood normally
Inadequate blood flow cannot meet tissue needs
Hypovolemic shock results from large-scale blood loss
Vascular shock results from extreme vasodilation and decreased peripheral resistance
Cardiogenic shock results when an inefficient heart cannot sustain adequate circulation
Edema : abnormal increase in amount of interstitial fluid
Caused by either an increase in outward pressure (driving fluid out of the capillaries) or a decrease in inward pressure
Structural and Functional differences between Blood Vessel Types
Arteries: carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus
Muscular arteries
Elastic arteries give rise to muscular arteries
Also called distributing arteries because they deliver blood to body organs
Account for most of named arteries
Active in vasoconstriction
Elastic arteries: thick-walled with large, low-resistance lumen
Act as pressure reservoirs that expand and recoil as blood is ejected from heart
Arterioles
Arterioles: smallest of all arteries
Control flow into capillary beds via vasodilation and vasoconstriction of smooth muscle
Also called resistance arteries because changing diameters change resistance to blood flow
Lead to capillary beds
Blood vessels: delivery system of dynamic structures that begins and ends at heart
Veins: carry blood toward heart; deoxygenated except for pulmonary circulation and umbilical vessels of fetus
Formation begins when capillary beds unite in postcapillary venules and merge into larger and larger veins
Venules
Capillaries unite to form postcapillary venules
Consist of endothelium and a few pericytes
Very porous; allow fluids and WBCs into tissues
Larger venules have one or two layers of smooth muscle cells
Have all tunics, but thinner walls with large lumens compared with corresponding arteries
Blood pressure lower than in arteries, so adaptations ensure return of blood to heart
Other adaptations
Venous valves
Prevent backflow of blood
Most abundant in veins of limbs
Venous sinuses
Flattened veins with extremely thin walls
Tunica media is thin, but tunica externa is thick
Contain collagen fibers and elastic networks
Capillaries: direct contact with tissue cells; directly serve cellular needs
Microscopic vessels; diameters so small only single RBC can pass through at a time
Walls just thin tunica intima; in smallest vessels, one cell forms entire circumference
Supply almost every cell
Functions: exchange of gases, nutrients, wastes, hormones, etc., between blood and interstitial fluid
Layers of the Heart
Myocardium: circular or spiral bundles of contractile cardiac muscle cells
Endocardium: innermost layer; is continuous with endothelial lining of blood vessels
lines the heart chambers
Epicardium: visceral layer of serous pericardium
Major Blood Vessels
Coronary arteries
Heart receives 1/20th of body’s blood supply
Left coronary artery supplies interventricular septum, anterior ventricular walls, left atrium, and posterior wall of left ventricle; has two branches:
Both left and right coronary arteries arise from base of aorta and supply arterial blood to heart
Right coronary artery supplies right atrium and most of right ventricle; has two branches:
Right marginal artery
Posterior interventricular artery
Coronary veins
Several anterior cardiac veins empty directly into right atrium anteriorly
Coronary sinus empties into right atrium; formed by merging cardiac veins
Middle cardiac vein in posterior interventricular sulcus
Small cardiac vein from inferior margin
Great cardiac vein of anterior interventricular sulcus
Cardiac veins collect blood from capillary beds
Cardiac Cycle and the ECG
Electrocardiograph can detect electrical currents generated by heart
Electrocardiogram (ECG or EKG) is a graphic recording of electrical activity
Electrodes are placed at various points on body to measure voltage differences
12 lead ECG is most typical
Composite of all action potentials at given time; not a tracing of a single AP
Main features
P wave: depolarization of SA node and atria
QRS complex: ventricular depolarization and atrial repolarization
T wave: ventricular repolarization
P-R interval: beginning of atrial excitation to beginning of ventricular excitation
S-T segment: entire ventricular myocardium depolarized
Q-T interval: beginning of ventricular depolarization through ventricular repolarization
Normal ECG Tracings
sinus rhythm
Abnormal ECG Tracings
Second-degree heart block
AV node fails to conduct some SA node impulses
There are more P waves than QRS waves
There are usually two P waves for each QRS wave
Ventricular fibrillation
Electrical activity is disorganized. Action potentials occur randomly throughout the ventricles
Results is chaotic, grossly abnormal ECG deflections
Seen in acute heart attack and after an electrical shock
Junctional rhythm
SA node is nonfunctional
P waves are absent
AV node paces the heart at 40-60 beats per minute
Cardiac cycle: blood flow through heart during one complete heartbeat
Atrial systole and diastole are followed by ventricular systole and diastole
Cycle represents series of pressure and blood volume changes
Diastole: period of heart relaxation
Mechanical events follow electrical events seen on ECG
Systole: period of heart contraction
Major Components and Functions of Blood
Functions: Blood is the life-sustaining transport vehicle of the cardiovascular system
Regulation
What blood regulates
Maintaining body temperature by absorbing and distributing heat
Maintaining normal pH using buffers; alkaline reserve of bicarbonate ions
Maintaining adequate fluid volume in circulatory system
Protection
How blood protects
Preventing blood loss
Plasma proteins and platelets in blood initiate clot formation
Preventing infection
Agents of immunity are carried in blood: Antibodies, Complement Proteins, White Blood Cells (WBC)
Transport
What blood transports
Delivering O2and nutrients to body cells
Transporting metabolic wastes to lungs and kidneys for elimination
Transporting hormones from endocrine organs to target organs
Components
Formed elements
Erythrocytes (red blood cells, or RBCs)
Functions
Erythrocytes are small-diameter (7.5 μm) cells that contribute to gas transport
Cell has biconcave disc shape, is anucleate, and essentially has no organelles
Filled with hemoglobin (Hb) for gas transport
Production
Hematopoiesis: formation of all blood cells
Erythropoiesis: formation of Red Blood cells
Occurs in red bone marrow
Hormonal Control
Erythropoietin (EPO): hormone that stimulates formation of RBCs
Always small amount of EPO in blood to maintain basal rate
Released by kidneys (some from liver) in response to hypoxia
Life Span
Life span: 100–120 days
RBCs are anucleate, so cannot synthesize new proteins, or grow or divide
Old RBCs become fragile, and Hb begins to degenerate
Leukocytes (white blood cells, or WBCs)
Leukocytes, or WBCs, are the only formed element that is complete cell with nuclei and organelles
Function in defense against disease
Can leave capillaries
Move through tissue spaces
Leukocytosis: increase in production of WBCs as a response to infection
Separated into 2 major categories
Granulocytes: contain visible cytoplasmic granules
Eosinophils
2-4% of WBC count
Structure: biobed nucleus, red cytoplasmic granules
Neutrophils
50-70% of WBC count
Structure: multiobed nucleus, pale red and blue cytoplasmic granules
Basophils
0.5-1% of WBC count
Structure: Biobed nucleus, purple-black cytoplasmic granules
Agranulocytes: do not contain visible cytoplasmic granules
Lymphocytes
25-45% of WBC count
Structure: large spherical nucleus, thin rim of pale blue cytoplasm
Monocytes
3-8% of WBC count
Structure: kidney-shaped nucleus, abundant pale blue cytoplasm
Leukopoiesis: production of WBCs are stimulated by two types of chemical messengers (interleukins, Colony-stimulating factors) from red bone marrow and mature WBCs
Platelets
Platelet: fragments of larger megakaryocyte
Involved in blood clotting process
Function: form temporary platelet plug that helps seal breaks in blood vessels
Platelet formation is regulated by thrombopoietin
Blood has three layers
Erythrocytes on bottom (~45% of whole blood)
Hematocrit: percent of blood volume that is RBCs
WBCs and platelets in Buffy coat (< 1%)
Thin, whitish layer between RBCs and plasma layers
Plasma on top (~55%)
Blood plasma is straw-colored sticky fluid
Albumin: makes up 60% of plasma proteins