Cardio anatomy/definitions Flashcards
Age Related Structural Changes of the Heart
- Deposition of lipids (fats, oils), lipofuscin (granules), & amyloid (protein aggregates) in smooth muscles tissue
- ↑connective tissue & fibrousity
- Hypertrophy left ventricle
-↑diameter of atria - Valves stiffen and calcify
- ↓pacemaker cells in sinoatrial and atrioventricular nodes
- ↓conduction fibers
- ↓ sensitivity to autonomic innervation
- ↓rate of tension development during contraction
Age Related Functional Consequences of the Heart
- ↓excitability
- ↓cardiac output
- ↓venous return
- Susceptibility to dysrhythmia
- ↓maximal heart rate that can be attained
- ↓(efficiency) dilation of cardiac arteries during activities
- ↓(efficiency) left ventricular filling in early diastole leading to reduced stroke volume
- ↑afterload, leading to weakening of heart muscle
Age Related Structural Changes of the Blood Vessels
- Altered ratio of smooth muscle to connective tissue and elastin in vessel walls
- ↓Baroreceptor responsiveness
- Susceptibility to plaque formation within vessel
- Rigidity & calcification of large arteries (esp. aorta)
- Dilation & ↑tortuosity of veins
Age Related Functional Consequences of the Blood Vessels
- ↓efficient delivery of oxygenation blood to muscle and organs
- ↓cardiac output
- Less efficient venous return
- Susceptibility to venous thrombosis
- Susceptibility to orthostatic hypotension
Pulmonary Function Anatomical and Physiological Changes with age
- Stiffened cartilage in ribs & vertebrae
- ↑stiffness/compression of annulus fibrosis in intervertebral disks
- ↓strength & endurance of respiratory musculature
- ↓elastic recoil for expiration
- ↓vital capacity
- Greater mismatch between ventilation & perfusion within lung
Pulmonary Function Functional consequences with age
- Greater airspace within aveoli = less surface area for O2/CO2 exchange
- ↑work of breathing
- ↓force during inspiration
- ↓efficient cough
- ↓exercise tolerance
- ↓resting PaO2
Cardiovascular Consequences of Bed Rest and Immobility
- ↓ Exercise tolerance
- ↓CO & ↓VO2max
- Due to limited SV resulting from reduced blood volume, limited ventricular filling & limited end-diastolic volume
- ↑Resting HR
- To compensate for ↓CO
- ↓Resting and maximum SV
- ↑Venous Compliance
- Which results in increased venous pooling (especially upon return to upright positions)
- ↓Orthostatic Tolerance
- Venous Pooling
Hematologic Consequences of Bed Rest and Immobility
↓ Blood Volume
↓ Red blood cells (RBCs)
Bed rest reduces RBC mass by 5% to 25%: decreased oxygen carrying capacity (decreasing O2 to exercising muscles)
Combination: decreased RBCs and contracted plasma volume may be represented in an elevated hematocrit (HCT)
↑risk of deep vein thrombosis (DVT)
Elevated HCT: increases the resistance to blood flow that may overly stress a compromised cardiovascular system and increase the risk of DVTs
Apex of heart
The lowest part of the heart formed by the inferolateral part of the left ventricle.
It projects anteriorly and to the L at the level of the 5th intercostal space and the L midclavicular line.
Base of heart
- The upper border of the heart
- Involving the left atrium, part of the right atrium, and the proximal portions of the great vessels.
- It lies approximately below the second rib at the level of the second intercostal space.
Endocardium
The endothelial tissue that lines the interior of the heart chambers and valves.
Epicardium
- The serous layer of the pericardium.
- contains the epicardial coronary arteries and veins, autonomic nerves, and lymphatics.
Myocardium
The thick contractile middle layer of muscle cells that forms the bulk of the heart wall.
Pericardium
A double-walled connective tissue sac that surrounds the outside of the heart and great vessels
Aorta
The body’s largest artery and the central conduit of blood from the heart to the body.
The aorta begins at the upper part of the left ventricle, and after ascending for a short distance arches backward and to the left (arch of the aorta).
It then descends within the thorax (thoracic aorta) and passes into the abdominal cavity (abdominal aorta)
Superior vena cava
The vein that returns venous blood from the head, neck, and arms to the right atrium
Inferior vena cava
The vein that returns venous blood from the lower body and viscera to the right atrium
Pulmonary arteries
The arteries that carry deoxygenated blood from the right ventricle to the left and right lungs.
Pulmonary veins
The veins that carry oxygenated blood from the right and left lungs to the left atrium.
Coronary Arteries
carry oxygenated blood to the myocardium.
R&L coronary arteries arise from the ascending aorta just beyond where the aorta leaves the L ventricle
Sinus node artery supplies
R atrium
R marginal artery supplies
R ventricle
Posterior descending artery supplies
Inferior walls of both ventricles
Inferior portion of the interventricular septum
Circumflex artery supplies
L atrium
Posterior and lateral walls of the L ventricle
Anterior and interior walls of the L ventricle
L anterior descending artery supplies
Anterior portion of the interventricular septum
Innervation of the Heart
- Cardiac automaticity is intrinsic to the SA node
- ANS influences the HR, rhythm, and contractility
- Sympathetic - release of epinephrine and norepinephrine. Stimulates to increase contractility and beat faster
- Parasympathetic - acetylcholine from vagus. Slows HR from influence on SA node.
Cardiac conduction system
SA node
internodal tracts,
AV node
Common AV bundle/bundle of His
R and L bundle branches
Purkinje fibers
Normal blood volume
4-5 L (women slightly less than mens)
Hypovolemia
- Decreased blood volume, specifically the volume of plasma.
- Causes: bleeding, dehydration from vomiting, diarrhea, sweating, severe burns, and diuretic medications used to treat hypertension.
- Signs and symptoms: orthostatic hypotension, tachycardia, and elevated body temperature.
Hypervolemia
- Fluid overload, refers to increased blood plasma.
- Causes: excess intake of fluids (e.g., IV or blood transfusion) and sodium or fluid retention (e.g., heart failure, kidney disease).
- Signs and symptoms: swelling in the legs, ascites (fluid in the abdomen), and fluid in the lungs.
Plasma
- Liquid component of blood, in which the blood cells and platelets are suspended.
- Consists of water, electrolytes, and proteins, and
- Accounts for more than half of the total blood volume.
- Important in regulating blood pressure and temperature.
Red blood cells (aka erythrocytes)
- approximately 40% of blood volume.
- Contain hemoglobin, a protein that gives blood its red color and enables it to bind with oxygen.
Anemia
When the number of red blood cells is too low (anemia), the blood carries less oxygen, resulting in fatigue and weakness.
Polycythemia
Red blood cells is too high (polycythemia)
Blood is too thick
increasing the risk of stroke or heart attack.
Blood platelets (thrombocytes)
- Assist in blood clotting by clumping together at a bleeding site and forming a plug that helps to seal the blood vessel.
Thrombocytopenia
- Low number of platelets
- Increases the risk for bruising and abnormal bleeding.
Thrombocythemia
- High number of platelets
- Increases the risk of thrombosis, which may result in a stroke or heart attack.
Polycythemia
Red blood cells is too high (polycythemia)
Blood is too thick
increasing the risk of stroke or heart attack.
White Blood Cells (leukocytes)
Protect against infection.
A low number of white blood cells (leukopenia) increases the risk of infection.
An abnormally high number of white blood cells (leukocytosis) can indicate an infection or leukemia.
Different types of white blood cells
There are five main types of white blood cells (Fig. 6-3):
* Neutrophils: help protect the body against infections by ingesting bacteria and debris.
- Lymphocytes: consist of three main types - T lymphocytes and natural killer cells, which help protect against viral infections and can detect and destroy some cancer cells, and B lymphocytes, which develop into cells that produce antibodies.
- Monocytes: ingest dead or damaged cells and help defend against infectious organisms.
- Eosinophils: kill parasites, destroy cancer cells, and are involved in allergic responses.
- Basophils: participate in allergic responses.
Right atrium
Receives venous blood from the superior and inferior vena cava.
R ventricle
Receives venous blood from the right atrium through the tricuspid valve.
Pushes blood into the pulmonary artery and pulmonary circulation.
Left atrium
Receives arterial blood from the pulmonary veins.
Left ventricle:
Receives blood from the left atrium. Pushes blood into the aorta and the systemic circulation.
Tricuspid valve
Prevents right ventricular blood from going back into the right atrium.
Pulmonary valve
Prevents blood from returning to the right ventricle.
Mitral valve
Prevents left ventricular blood from returning to the left atrium.
Aortic valve
Prevents the systemic blood from returning to the left ventricle.
Atrioventricular valves
Blood from each atrium flows to each ventricle through these valves. The valves close upon ventricular contraction to avoid backflow.
Atrial systole
The contraction of the right and left atria pushing blood into the ventricles.
Atrial diastole
The period between atrial contractions when the atria are repolarizing.
Ventricular systole
Contraction of the right and left ventricles pushing blood into the pulmonary arteries and aorta.
Ventricular diastole
The period between ventricular contractions when the ventricles are repolarizing.
Preload:
Refers to the tension in the ventricular wall at the end of diastole.
It reflects the venous filling pressure that fills the left ventricle during diastole.
Afterload
Refers to the forces that impede the flow of blood out of the heart,
Primarily the pressure in the peripheral vasculature, the compliance of the aorta, and the mass and viscosity of blood.
Stroke volume (SV):
Refers to the volume of blood ejected by each contraction of the left ventricle.
Normal SV ranges from 60 to 80 ml depending on age, sex, and activity.
Cardiac output (CO):
The amount of blood pumped from the left or right ventricle per minute.
It is equal to the product of stroke volume and heart rate.
Normal CO for an adult male at rest is 4.5 to 5.0 L/min with women producing slightly less.
CO can increase up to 25 L/min during exercise.
CO = HRxSV
Baroreceptor reflex
- Mechanoreceptors that detect changes in pressure. (and helps manage BP)
- Includes arterial baroreceptors (high pressure receptors located in the carotid sinus, aortic arch, and origin of the right subclavian artery) and cardiopulmonary receptors (low pressure receptors).
- Sympathetic activation leads to increased cardiac contractility, increased heart rate, vasoconstriction, and arterial vasoconstriction, ultimately leading to increased blood pressure via elevation of total peripheral resistance and cardiac output. (increasing HR)
- Parasympathetic activation leads to a decrease in heart rate and a small decrease in contractility, resulting in a decrease in blood pressure. (decreasing HR)
Bainbridge reflex
- An increase in venous return stretches receptors in the wall of the right atrium which sends vagal afferent signals to the cardiovascular center within the medulla.
- The signals inhibit parasympathetic activity, resulting in an increased heart rate.
Chemoreceptor reflex
- Located in the carotid bodies and the aortic body
- Respond to changes in pH status and blood oxygen tension.
- Arterial partial oxygen pressure of < 50 mm Hg or in conditions of acidosis— the chemoreceptors stimulate the respiratory centers and increase the depth and rate of ventilation.
In addition, the ensuing activation of the parasympathetic system reduces heart rate and myocardial contractility. In the case of persistent hypoxia, the CNS will be direct stimulated with a resultant increase in sympathetic activity.
Valsalva maneuver
- Forced expiration against a closed glottis produces increased intrathoracic pressure, increased central venous pressure, and decreased venous return.
- The resultant decrease in cardiac output and blood pressure is sensed by baroreceptors, which reflexively increase heart rate and myocardial contractility through sympathetic stimulation.
- When the glottis opens, venous return increases and blood pressure and heart contractility increase.
- The increase in blood pressure is sensed by baroreceptors, which reflexively decrease the heart rate through the parasympathetic efferent pathways.
What stimulus activates the bainbridge reflex?
increase in venous return
What converges at the base of the heart to create the cardiac plexus?
Vagus and sympathetic cardiac nerves
What hormone is released by the vagus nerve to create parasympathetic reaction by the heart?
Acetylcholine
What is the force that impedes the flow out of the heart?
Afterload
What is the volume of blood ejected by each contraction of the L ventricle
Stroke Volume
Where to palpate the dorsalis pedal pulse
palpable between the distal end of the tibia and the proximal talus on the anterior aspect of the ankle.
What is the double-walled connective tissue sac that surrounds the outside of the heart and great vessels?
Pericardium.
layers of the pericardium contain fluid that serve as a constant source of lubrication for the heart and limits infection.
Which structure serves as a conduit for both food and air?
Pharynx
Part of both the respiratory and digestive systems. Specifically, it is a passageway that connects the nasal and oral cavities to the larynx and the oral cavity to the esophagus.
Which of the following coronary arteries typically supplies blood to the atrioventricular node?
right coronary artery
The right coronary artery supplies blood to the atrioventricular node in 90% of individuals. The left circumflex artery supplies blood to the atrioventricular node in the remaining 10%
Which muscle does the subclavian artery course through?
Scalenes
The subclavian artery courses through the anterior and middle scalenes. This is an area that can cause an issue with thoracic outlet syndrome resulting from compression of the subclavian artery by the scalenes.
Which of the following muscles is a primary contributor to forced expiration?
Rectus Abdominis
Internal intercostals
Approximately how much of the total blood volume is located in the venous system?
67%
Approximately 2/3 of total blood volume is stored within the venous vasculature.
Veins have a greater ability to distend compared to arteries and therefore can expand to accommodate higher volumes of blood.
In fetal heart circulation, which structure connects the two atria?
foramen ovale
The foramen ovale connects the two atria and allows blood entering the right heart to bypass the pulmonary circuit and the collapsed, nonfunctional fetal lungs.
Which characteristic has a direct relationship with an individual’s lung volume?
height
Height has a direct relationship with lung volume and therefore should be measured and recorded.
Which arteries are considered branches of the left coronary artery?
circumflex artery and left anterior descending artery
The left coronary artery branches into the circumflex artery and left anterior descending artery. The right coronary artery branches into the right marginal artery and posterior descending artery.
Where is pleural fluid located?
between the visceral and parietal pleura
The pleural fluid resides between the visceral pleura on the surface of the lungs and the parietal pleura on the surface of the chest cavity. The pleural fluid provides lubrication to reduce friction between the pleural layers during inspiration.
Blood from the medial side of the lower extremity is drained by the:
great saphenous vein
The great saphenous vein brings deoxygenated blood up from the medial side of the leg where it empties into the femoral vein and continues toward the heart via the inferior vena cava.
Systemic circulation pathways
L ventricle (O2) → aorta → arteries → arterioles →
capillaries in the tissues of the body.
Capillaries (no O2 aka deoxygenated blood) → venules → veins.
Veins of UE and LE:
* Superficial: beneath the skin between the two layers of superficial fascia
- Deep: the deep veins accompany the arteries.
Both types of veins have valves, but they are more numerous in the deep veins than in the superficial veins and in lower extremity veins more than upper extremity veins.
Rate pressure product (RPP)
- Index of myocardial oxygen consumption and coronary blood flow.
- physiological correlate onset of angina pectoris or ECG abnormalities in pts with heart disease
- These S&S are typically reproduced at same RPP
*RPP = HR x SBP
Which 2 physiological processes occur from forced expiration and closed glottis in the Valsalva maneuver?
decreased venous return
increased central venous pressure
Increased BP
Decreased HR
What is the amount of blood pumped from L or R ventricle per minute termed?
cardiac output
Ejection fraction
- Measure of L ventricular contractility
- Stroke volume/L ventricular end-diastolic volume (amount of blood in before contraction and after contraction)
- Normal = 55-70%
- best indicator of cardiac function.
Perfusion Index
- ratio of pulsatile blood flow to non-pulsatile static blood flow in peripheral tissue
- normally monitored with pulse oximeter.
- indication of the pulse strength at the sensor site
Frank-Starling relationship
- stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (end diastolic volume)
- an increase in the preload will increase the cardiac output
Frank-Starling relationship
- stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (end diastolic volume)
- an increase in the preload will increase the cardiac output
Anatomic Dead Space (VD)
The volume of air that occupies the non-respiratory conducting airways.
Expiratory Reserve Volume (ERV)
The maximal volume of air that can be exhaled after a normal tidal exhalation.
ERV is approximately 15% of total lung volume.
Forced Expiratory Volume (FEV)
The maximal volume of air exhaled in a specified period of time: usually the 1st, 2nd, and 3rd second of a forced vital capacity maneuver.
Forced Vital Capacity (FVC)
The volume of air expired during a forced maximal expiration after a forced maximal inspiration.
Functional Residual Capacity (FRC)
The volume of air in the lungs after normal exhalation.
FRC = ERV + RV. FRC is
approximately 40% of total lung volume.
Inspiratory Capacity
The maximal volume of air that can be inspired after a normal tidal exhalation.
IC = TV + IRV. IC is approximately 60% of total lung volume.
Inspiratory Reserve Volume (IRV)
The maximal volume of air that can be inspired after normal tidal volume inspiration.
IRV is approximately 50% of total lung volume
Minute volume expiratory (VE)
The volume of air expired in one minute.
VE = TV › respiratory rate.
Peak Expiratory Flow (PEF)
The maximum flow of air during the beginning of a forced expiratory maneuver.
Residual Volume
The volume of gas remaining in the lungs at the end of a maximal expiration.
RV is approximately 25% of total lung volume.
Tidal Volume
Total volume inspired and expired with each breath during quiet breathing.
TV is approximately 10% of total lung volume.
500 mL
Total Lung Capacity (TLC)
The volume of air in the lungs after a maximal inspiration; the sum of all lung volumes.
TLC = RV + VC or TLC = FRC + IC.
What percentage of the vital capacity is a patient typically able to exhale during the forced expiratory volume in one second (FEV1)?
75%
FEV1 is the percentage of the vital capacity which is expired in the first second of a maximal expiration. This value is typically greater than 75% of vital capacity, but would not approach 100%. FEV1 is significantly reduced in obstructive lung disease due to increased airway resistance
What is the maximum voluntary ventilation (MVV)?
MVV refers to the maximum amount of air a subject can breathe in 12 seconds. The obtained value is expressed in liters per minute (L/min).
Vital Capacity (VC)
The volume change that occurs between maximal inspiration and maximal expiration
VC= TV + IRV + ERV.
VC is approximately 75% of total lung volume.
Which test is used to differentiate between restrictive and obstructive diseases?
static lung volumes
Static lung volumes include total lung capacity, functional residual capacity, and residual volume. These measures are useful in differentiating restrictive and obstructive diseases as well as detecting hyperinflation.
Inspiratory Capacity
The maximal volume of air that can be inspired after a normal tidal exhalation.
IC = TV + IRV. IC is approximately 60% of total lung volume.
Apnea
absence of spontaneous breathing
Biot’s
irregular breathing: breaths vary in depth and rate with periods of apnea; often associated with increased intracranial pressure or damage to the medulla
Bradypenia
slower than normal respiratory rate;
‹ 12 breaths/minute in adults;
may be associated with neurologic or electrolyte disturbance, infection or high level of cardiorespiratory fitness
Cheyne-Stokes (periodic)
decreasing rate and depth of breathing with periods of apnea;
can occur due to central nervous system damage
Eupnea
normal rate and depth of breathing
Hyperpnea
increased rate and depth of breathing
Hypopnea
decreased rate and depth of breathing
Kussmaul’s
deep and fast breathing; often associated with metabolic acidosis
Paradoxical
chest wall moves in with inhalation and out with exhalation; due to chest trauma or paralysis of the diaphragm
Tachypnea
faster than normal respiratory rate
>20 breaths/minute in adults
What is the typical RPE scale?
6-20
Self-assessment of difficulty of workload
RPE Scale – Very, very light
7
RPE Scale – Very light
9
RPE Scale – Fairly Light
11
RPE Scale – Somewhat Hard
13
RPE Scale – Hard
15
RPE Scale – Very Hard
17
RPE Scale – Very Very Hard
19
What is 13 on the RPE equivalent to MHR
70%
What is the upper limit (on 6-20 RPE scale) of prescribed training HR in early cardiac rehab
RPE of 11-13
When is RPE typically used?
after heart transplant, patients taking beta blockers, individuals who cannot feel their pulse
What intensity for warm-up using RPE scale (6-20)
10
A rating of perceived exertion (RPE) scale is used to quantify a patient’s overall sense of effort during activity. The warm-up and cool-down portions of the exercise program should occur at an RPE value of 9-11 using Borg’s (20-point) Rating of Perceived Exertion Scale.
An RPE of 16 (on 6-20 scale) is equivalent to what MHR%?
85%
EKG stuff
