Heart Anatomy and Physiology

• Exam III contents include: Heart and Neck Vessels, Peripheral Vascular and Lymphatics, Lungs and Thorax + Other previous material.

Heart Anatomy and Physiology

• Precordium, pericardium, pericardial sac, myocardium, endocardium, and mediastinum
• Pericardium/Pericardial Sac consists of two outer layers called parietal and fibrous.
• Myocardium is the muscle that makes the heart beat.
• Endocardium lines the inside of the myocardium.
• Mediastinum refers to the spaces in the chest that hold the heart.

Heart Position in Chest Cavity

• Base (top) sits at the 2nd intercostal space, right side, along the right and left sternal border.
• Apex (bottom) lies at the 5th intercostal space, left side, on the midclavicular line.

Circulation of the Heart

• Unoxygenated blood flows through the superior/inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonic valve, and pulmonary artery before heading to the lungs.
• Oxygenated blood returns from the lungs via pulmonary veins, entering the left atrium, mitral valve, left ventricle, aortic valve, and aorta, and is then distributed to the rest of the body.

Fetal Circulation

• Lungs are nonfunctioning.
• Oxygenated blood is pumped from the placenta to the right side of the heart.
• Two openings act as shunts that direct blood straight to the aorta and systemic circulation foramen ovale and ductus arteriosus.
• Fetal shunts typically close within 10 to 15 hours, but can take up to 48 hours where murmurs may be auscultated.
• Failure of fetal shunts to close indicates a congenital abnormality.
• Newborns are typically pinkish, show no signs of dyspnea and do not have liver enlargement.

Heart Valves

• S1 heart sound occurs when the tricuspid and mitral valves CLOSE.
  • The tricuspid valve separates the right atrium and ventricle.
  • The mitral valve separates the left atrium and ventricle.
• S2 heart sound occurs when the aortic and pulmonary valves CLOSE.
  • The aortic valve separates the left ventricle and aorta.
  • The pulmonary valve separates the right ventricle and pulmonary artery.

Systole and Diastole

• Systole is when the heart contracts and blood is ejected out.
• Diastole is when the heart relaxes and blood fills inside.

Apical Pulse

• Apical pulse or PMI (point of maximal impulse) is found at the 5th intercostal space on the midclavicular line.
• A displaced apex signifies enlargement of the right ventricle or right atrium due to lung/cardiac disease

Heart Sounds

• S1 starts systole and produces a "lub" sound due to the closing of the atrioventricular (AV) valves, notably the tricuspid and mitral valves and is loudest at the apex.
• S2 starts diastole and produces a "dub" sound from closing of the semilunar valves like the pulmonary and aortic valves and is loudest at the base.

Extra Heart Sounds

• S3 (Ventricular gallop) occurs during diastole, when the heart is normally silent. Sounds can be heard during ventricular filling, listen to all auscultatory areas with diaphragm and bell. Can be earliest sign of heart failure, overload, anemia, pregnancy, hypothyroidism + normal in children or athletes.
• S4 (Atrial gallop) occurs at the end of diastole when the ventricle resists filling, listen with diaphragm and bell and can be normal in older adults + coronary artery disease.

Stethoscope Use

• The diaphragm is best for high-pitched sounds.
• The bell is best for low-pitched sounds.
• Use both to assess the heart valves.
• Use the bell when assessing the carotid artery.

Cardiac Assessment

• Lift: area over the heart lifts each beat.
• Heave: increase in systolic pulsation that can be felt directly over the heart.
• Thrill: vibration/buzzing felt directly over the heart.

Bruits

• Indicates turbulation in the carotid artery
• Best assessed by listening with the bell of the stethoscope over the carotid artery.

Jugular Venous Distention

• Jugular venous distention indicates right heart problems.

Heart Failure

• Clinical signs: chest pain, shortness of breath, irregular heartbeat, jugular venous pressure, referred pain

Cardiac History and Risk Factors

• History: Surgery, heart diagnosis, chest pain, claudication, edema, hypotension, caffeine
• Risk: smoking, environment/conditions, family history

Key Terms

• Dyspnea: shortness of breath
• Dyspnea on Exertion (DOE): shortness of breath during exercise
• Paroxysmal Nocturnal Dyspnea (PND): shortness of breath while sleeping
• Angina: chest pain
• Orthopnea: shortness of breath while lying down
• Nocturia: waking up at night to urinate
• Orthostatic hypotension: sudden drop in blood pressure upon standing after being immobile for a long period of time

Cardiovascular Disease

• African Americans are at greater risk for cardiovascular disease due to socioeconomic factors.
• Stenosis: vessel thickening/stiffening due to scarring or plaque buildup.
• Regurgitation: backflow of blood due to valves that are not closing properly which sounds like murmurs and rumbles.
• Heart failure: heart cannot pump enough blood.

Peripheral Vascular and Lymphatics

• Veins drain deoxygenated blood and waste products from tissues back to the heart, have a low pressure system, valves to prevent backflow, thinner walls with greater diameter, and are more distensible to hold more blood.
• Capacitance is the ability to stretch.
• Arteries pump freshly oxygenated blood to all body tissues, operate under a high-pressure system, have strong walls with elastic fibers for stretching, and generate a pulse through pressure waves.

Blood Return to the Heart

• Blood returns to the heart through veins via skeletal and smooth muscle contractions and pressure gradients from breathing.

Aging Effects on Arteries

• Elastin decreases with age, reducing the body's ability to pump.

Peripheral Pulses

• Radial: wrist under the thumb
• Brachial: between the bicep and inner elbow
• Femoral: below the inguinal and anterior superior iliac spine
• Posterior Tibial: inside and below the ankle bone
• Carotid: on the neck
• Dorsalis Pedis: on the foot

Grading Pulses

• 0: absent
• 1+: weak
• 2+: normal
• 3+: increased, full bounding

Capillary Refill Test

• Checking by pushing down on nail bed to cut off circulation (skin turns white), and blood (color) to return, in less than 3 seconds.

Homan's Sign

• Involves forcefully straightening the leg (dorsiflex) and pulling the foot towards the body where pain in the calf indicates a positive sign may check for DVT (deep vein thrombosis).

Lymphatic System

• Circulates lymph, retrieves excess fluid and plasma from the interstitium, and returns it to the blood supply.

Lymph Nodes

• Cervical Nodes: Head, neck, and face
• Axillary Nodes: Arms, chest, and upper back.
• Inguinal Nodes: Legs, lower abdomen, and pelvis.
• Mesenteric Nodes: Abdomen, specifically the intestines.
• Mediastinal Nodes: Chest (thoracic cavity).
• Popliteal Nodes: Lower leg and foot.
• Supraclavicular Nodes: Neck and upper chest.
• Normal nodes are non-palpable and abnormal are palpable, hard, fixed, and swollen.

Doppler Stethoscope

• Used when a pulse cannot be manually found.
• Magnifies the pulse and produces a whooshing sound + determines Peripheral Artery Disease (PAD).

Arterial vs. Venous Symptoms

• Acute Arterial: distal to occlusion, may involve ENTIRE leg, throbbing, sudden onset, pain, pallor, pulselessness, paresthesia, paralysis, history of vascular disease, procedure, trauma
• Acute Venous: CALF, intense sharp deep muscle tender to touch, sudden onset, pain may increase with sharp dorsiflexion, red warm swollen leg
• Chronic Arterial: deep muscle pain, usually in calf, intermittent claudication, feels like a cramp, numbness, tingling, feeling of cold, chronic, onset gradual after exertion, activity bothers with elevation, cool pale skin, older adults, smoking, hypertension
• Chronic Venous: calf, lower leg, aching, tiredness, feeling of fullness, chronic pain, increases at end of the day, bothers with prolonged standing, sitting, relief elevation, lying, walking, edema, weeping ulcers, at risk job, obesity, pregnancy, bed rest, heart failure

Claudication, DVT, Venous Stasis, and Aneurysm

• Claudication: muscle fatigue or pain when walking caused by peripheral artery disease (PAD).
• DVT: deep vein thrombosis, usually in legs caused by venous stasis, injury, and hypercoagulability.
• Venous Stasis: ulcers due to abnormal vein function caused by inadequate venous return, immobility, pregnancy, obesity.
• Aneurysm: ballooning/weakening of an artery caused by atherosclerosis weakening of arterial walls, hypertension (high BP).

Pitting Edema

• Press skin for 5 seconds. Non Pitting edema: no indentations should be left
• 1+: mild, slight indentation, no swelling
• 2+: moderate, indentation subsides rapidly
• 3+: deep pitting, indentation remains for a short time, leg appears swollen
• 4+: very deep pitting, indentation lasts along time, leg is grossly swollen and distorted

Lungs

Lung Location

• Lungs are located in the pleural cavity.
• Apex (top): 3-4 cm above the clavicles
• Base (bottom): rests on the diaphragm. Anterior is the front while posterior is located at T10 to T12 on inspiration.
• The left lung is smaller with 2 lobes, narrower, and longer.
• The right lung is shorter, bigger, and has 3 lobes.

Respiration Physiology

• Respiration is involuntary controlled by the brain stem (pons and medulla control respiration).
• Hypercapnia (increased CO2) stimulates breathing.
• Hypoxemia (decreased O2) also stimulates breathing.

Muscles of Respiration

• Includes the muscles of the neck, shoulders, and abdomen.
• Sternal and intercostal retraction.
• Abdominal muscles contract to push the diaphragm upwards to squeeze the lungs.

Angle of Louis

• The angle of Louis can be found at the 2nd rib, it is where the trachea bifurcates or splits into branches.

APGAR Scoring System

• Appearance, pulse, grimace, activity, and respiration.
• Assesses the heart rate, respiratory effort, muscle tone, reflex irritability, and color of newborns in order to assess health.
• Is performed at 1 minute and 5 minutes after birth.
• A score of 7-10 signifies good condition so only suctioning of the nose and mouth is needed.

Lung Assessment Techniques

• Inspection, percussion, palpation, and auscultation.
• Breathing should be deep and complete

Breath Sounds

• Bronchial: over trachea/larynx, expiration is greater than inspiration, high pitch, loud, anterior only
• Bronchovesicular: heard over major bronchi, moderate pitch/amplitude, anterior/posterior, inspiration=expiration
• Vesicular: heard over peripheral lung fields, low pitch, soft, anterior/posterior, inspiration greater than expiration

Resonance and Hyperresonance

• Resonance is normal in adult lungs where low pitch drumming noise, fast, indicative emphysema.
• Hyperresonance is normal in children but in adult lungs, high pitched drumming noise, indicative of too much air, musical.

Diaphragmatic Excursion

• Normal excursion is 3-5 cm, should move symmetrically on both sides.
• Less than 3 cm may indicate restrictive lung diseases, pleural effusion, and diaphragm dysfunction.
• If one side moves less than the other, it can indicate unilateral lung disease.

Assessing Chest

• Diaphragmatic excursion measures the contraction of the diaphragm.
• Respiratory expansion measures the equality of the chest on both sides when breathing.
• Chest should be twice the size as the back, barrel chest would cause the AP diameter to be different than 2:1.

Tactile Fremitus Assessment

• Palpate to feel for vibrations on the chest wall while the patient speaking

Adventitious Sounds

• Crackles/Rales: short popping sounds, heard on inspiration, not cleared with coughing.
  • Pulmonary edema, pneumonia
• Ronchi (wheeze): high pitched, musical, squeaking sounds, air is compressed.
  • Tumors, asthma, bronchitis, emphysema
• Stridor: high pitched crowing sound, louder over neck than chest, obstruction or swollen upper airway.
  • Epiglottis/croup.
• Pleural friction rub: coarse and low pitched, grating quality, sounds like crackles but close to the ear.
  • Caused when pleurae become inflamed and lose normal lubrication.
• Axillary: armpit region
• Intercostal spaces: muscles used during labored breathing
• Paroxysmal nocturnal dyspnea: trouble breathing while sleeping
• Atelectasis: collapsed lung
• Retraction: body is using extra muscles to help with breathing due to difficulty in air intake
• Tachypnea: rapid shallow respirations (less than 20-24)
  • Fever, exercise, respiratory distress
• Bradypnea: slow respirations (less than 10)
  • Drug induced, increased intracranial pressure, coma
• Hyperventilation: increase in depth and rate
• Kussmual's respirations: increased rate/depth in attempt to compensate for acidosis
  • Diabetic ketoacidosis
• Cheyne Stokes: cycle of waxing/waning respirations in a regular pattern, increasing then decreasing rate and depth (periods of apnea)
  • Increased ICP, drug overdose, meningitis, renal failure. Normal in infants.

Age Related Changes for Lungs and Thorax

• More calcified costal cartilages: less mobile thorax
• Decreased strength of respiratory muscles
• Lungs more rigid, harder to inflate
• Decreased ventilation of lung bases
• Fewer alveoli
• Kyphosis: exaggerated posterior curvature of spine