Circulatory and Respiratory System

Flashcards of key vocabulary from the lecture notes.

Cardiac Cycle

All of the mechanical events that occur during a complete heartbeat, from its generation to the beginning of the next heartbeat.

Systole

Alternate between contraction.

Diastole

Alternate between relaxation.

Heart rate

The number of heart beats per minute.

Stroke volume

The volume of blood ejected from the ventricle with each contraction.

Cardiac output

Amount of blood pumped by the heart per minute.

Venous return

The rate of blood flow back to the heart.

End-diastolic volume

The volume of blood in the ventricles at the end of diastole.

End-systolic volume

The volume of blood remaining in the ventricles at the end of systole.

Ejection fraction

The percentage of blood ejected from the ventricle with each contraction.

Preload

The initial stretching of the cardiac myocytes prior to contraction.

Afterload

The resistance against which the heart must pump.

Total peripheral resistance

The total resistance to blood flow in the systemic circulation.

Mean arterial blood pressure

The average arterial pressure throughout one cardiac cycle.

Chronotropic

Refers to the rate of contraction.

Inotropic

Refers to the force of contraction (myocardial contractility).

Dromotropic

Refers to the speed of conduction through the heart’s electrical conduction system.

Preload

Volume entering ventricles.

Afterload

Resistance left ventricle must overcome to circulate blood.

Inotropic State

The strength of contraction.

Preload

Capacity of ventricles to stretch at the end of diastole.

Frank-Starling Mechanism

The heart’s ability to change its force of contraction in response to changes in LV filling.

Afterload

Resistance to ventricular ejection.

Inotropic State

Positive inotropes shift the curve to the left, which enable cardiac muscle to generate more force at any given preload.

Systolic BP (SBP)

Pressure in arteries during ventricular systole.

Diastolic BP (DBP)

Pressure in arteries during ventricular diastole.

Pulse pressure

SBP – DBP.

Mean arterial pressure (MAP)

Weighted average of SBP and DBP.

Orthostatic Hypotension

Drop in BP that accompanies the change from supine to standing.

Total Peripheral Resistance (TPR)

The resistance to blood flow offered by all of the systemic vasculature.

Increased PNS tone

Decreases HR and SV.

Increased SNS tone

Increases HR and SV.

Increased EPI & NE concentrations

Increases HR and SV.

Increased renin-angiotensin-aldosterone pathway activity

Increases SV and plasma volume.

Increased anti-diuretic hormone (ADH) concentration

Increases SV and plasma volume.

Increased atrial natriuretic peptide (ANP) concentration

Decreases SV and opposes the renin-angiotensin-aldosterone pathway.

Increased SNS tone

Vasoconstriction.

Increased EPI & NE concentrations

Vasoconstriction or vasodilation.

Increased Angiotensin II concentration

Vasoconstriction.

Beta Blocker

Decreases stimulation of beta-adrenergic receptors in the heart and blood vessels. Result: Decreased HR and SV, and vasodilation.

Calcium channel blocker

Decreases intracellular calcium in the heart and blood vessels. Result: Decreased HR and SV, and vasodilation.

Angiotensin Converting Enzyme (ACE) inhibitor

Decreases conversion of angiotensin I -> angiotensin II. Result: Decreased production of aldosterone, increased urinary excretion of sodium and water, and vasodilation.

Diuretic

Increases urine output. Result: Decreased Q

Angiotensin II Receptor Blocker (ARB)

Decreases receptor binding of angiotensin II. Result: Decreased stimulation of aldosterone secretion, increased urinary excretion of sodium and water, and Vasodilation.

Renin Inhibitor

Inhibits the binding of renin to angiotensinogen. Result: Decreased production of angiotensin II and stimulation of aldosterone secretion, increased urinary excretion of sodium and water, and Vasodilation.

Baroreceptors

Sense degree of stretch in vessels.

Lymphatic System

Network of lymph, lymph vessels, lymph nodes, and lymphatic organs.

Edema

An abnormal increase in interstitial fluid if net filtration exceeds net reabsorption.

Ascites

Edema in the peritoneal cavity of the abdomen, most commonly seen in individuals with cirrhosis of the liver.

Lymphedema

Progressive swelling that occurs when protein-rich fluid accumulates in the interstitium.

Visceral Pleura

Covers the surface of each lung and is inseparable from the tissue of the lung.

Parietal Pleura

Inner surface of chest wall, diaphragm, and mediastinum.

Pleurisy

Inflammation of the pleurae. Sharp chest pains are the primary symptom.

Diaphragm

Primarily innervated by phrenic nerve (C3-C5).

External intercostals

Primarily innervated by intercostal nerves (T1- T11).

Alveolar Surface Tension

An expression of intermolecular attraction at the surface of a liquid.

Surfactant

Detergent-like substance produced by type II alveolar cells that lowers alveolar surface tension and prevents alveoli from collapsing.

Pulmonary Compliance

How easily the lungs and chest wall can expand or contract.

Airflow

Pressure difference at the two ends of the airway.

Inspiratory Capacity (IC)

Maximal volume of air that can be inhaled.

Functional Residual Capacity (FRC)

Volume of air left in the lungs at the end of normal exhalation.

Vital Capacity (VC)

Volume of air that can be forced out the of the lungs following a maximal inhalation.

Total Lung Capacity (TLC)

Total volume of air that can be contained in the lungs

Forced expiratory volume (FEV1)

The maximum volume of air forcibly exhaled in 1 second.

Forced expired volume / forced vital capacity ratio (FEV1/FVC)

Percentage of FVC forcibly exhaled in 1 second.

Forced expiratory flow (FEF25-75)

Maximum mid-expiratory flow rate, measured by drawing a line between points representing 25% and 75% of FVC.

Obstructive Pulmonary Disease

Airflow is impeded during expiration and obstruction of the small airways, which compromises airflow out of the lungs Abnormally high amount of air left in the lungs at end-expiration.

Restrictive Pulmonary Disease

Lungs cannot fully expand during inspiration. Lung and/or chest wall stiffness, nerve and/or muscular damage, muscular weakness.

Barrel chest

Lungs are persistently over-inflated with air; trapped air and alveolar distension change the size and shape of the chest.

Fear of dyspnea

The sensation of being short of breath. Can occur at any ventilatory rate.

External respiration

Pulmonary gas exchange.

Internal respiration

Systemic gas exchange.

Partial pressure of gases in atmosphere

Increased pO2 -> increased diffusion rate of O2 from inspired air to alveoli to pulmonary circulation.

Distance over which diffusion occurs

Small diffusion distance (thin membranes) -> increased diffusion rate.

Molecular weight and solubility of gases

Lower molecular weight -> increased diffusion.

Transport of Oxygen in the Blood (Modes of Transport)

Dissolved in Plasma = ~1.5%.

Transport of Oxygen in the Blood (Modes of Transport)

Bound to hemoglobin (HbO2) = ~98.5%.

Transport of Carbon Dioxide in the Blood (Modes of Transport)

Dissolved in plasma= ~9%.

Transport of Carbon Dioxide in the Blood (Modes of Transport)

Bound to hemoglobin (HbCO2)= ~13%.

Transport of Carbon Dioxide in the Blood (Modes of Transport)

Bicarbonate ions (HCO3 -)= ~78%.

Oxygen-Hemoglobin Dissociation Curve

High pO2 facilitates loading of O2 onto Hb in RBCs. Occurs in pulmonary capillaries.

Facilitating Delivery

Low pO2 facilitates unloading of O2 to tissues. Occurs in systemic tissue capillaries, particularly exercising muscles.

Hypoxemia

Low PaO2.

Hypocapnia

Low PaCO2.

Hypercapnia

High PaCO2.

Acidemia

pH < 7.35.

Alkalemia

pH > 7.45.

Hypoxemia

Common symptoms of this include shortness of breath, rapid breathing, coughing, wheezing, and changes in skin color.

Stroke Volume

Cardiac output is defined as heart rate multiplied by what?

20 mmHg

Orthostatic hypotension is diagnosed by a drop in systolic blood pressure greater than what value?

10 mmHg

Orthostatic hypotension is diagnosed by a drop in diastolic blood pressure greater than what value?

Peritoneal Cavity

Ascites is a specific type of edema that occurs where?

Increase

Increased total vessel length will have what effect on TPR?

Increase

Increased blood viscosity will have what effect on TPR?

Decrease

Increased plasma ANP concentration will have what effect on TPR?

Decrease

Increased catecholamine levels will have what effect on TPR?

O2 and CO2

Arterial blood gas refers to the measurement of what two primary gasses?

Three

The right lung has how many lobes?

Two

The left lung has how many lobes?

Phrenic

The diaphragm is primarily innervated by which nerve?