Applied Physio Exam 3

Cardiovascular System

A system composed of the heart (pump), blood vessels (distributers), and blood (transport)

Heart

The pump of the cardiovascular system that circulates blood throughout the body.

Vasculature

The network of blood vessels that distribute blood.

Blood

The fluid that transports gases, nutrients, waste products, immune responses and heat.

Pulmonary System

The part of the cardiovascular system that carries deoxygenated blood from the right heart to the lungs, and returns oxygenated blood to the left heart.

Systemic System

The part of the cardiovascular system that carries oxygenated blood from the left heart through the aorta and to the body

Poiseuille’s Law

Governs steady state laminar flow in narrow tubes

Qv = ((πΔP a^4) / (8ηL) )(deltaP/ deltaX)

Compliance

The ability of a vessel to expand or contract in response to changes in pressure.

DeltaP (pressure) = Delta V (volume)/ C (compliance)

Viscosity

A measure of a fluid's resistance to flow, important for blood flow dynamics.

Hematocrit

The fraction of blood volume that is occupied by red blood cells.

Height of RBCs/Total height —> usually packed red blood cells = 45%

Waste Products in Blood

Includes CO2, urea, ammonia, and lactic acid among others.

Nutrients in Blood

Includes glucose, amino acids, fatty acids, vitamins, and minerals transported by blood.

Formed elements in blood

Components of blood that include red blood cells, white blood cells, and platelets.

Vascular Pressure

The pressure required to drive blood flow through the vascular system.

Arteries

Carry blood away from the heart, high pressure, oxygenated

Capillaries

max exchange of O2 and CO2, nutrients and waste

veins

carry blood to the heart, low pressure, deoxygenated

why do you need circulation in the cardiovascular system?

Diffusion to and from the environment is too slow

Diffusion Coefficient

1.8 × 10^-5 cm²/s

Diffusion Equation

X² = 2D (delta)t

R equation

(8n deltaX)/Pi a^4

Acid

A substance that dissociates in water to add H+ to a solution.

HA —> H+ + A-

Base

A substance that associates in water to remove H+ from a solution.

A- + H+ —> HA

Henderson-Hasselbalch Equation

An equation used to calculate pH based on the concentration of bicarbonate and carbonic acid.

It is expressed as pH = pK + log[A-]/[HA]

Bicarbonate System

The most important buffer system in the plasma that is significantly accelerated by carbonic anhydrase.

Carbonic Anhydrase

An enzyme that increases the rate of bicarbonate production by converting carbon dioxide and water into carbonic acid.

Respiratory Acidosis

A condition caused by hypoventilation leading to an increase in blood CO2 and a decrease in blood pH.

Respiratory Alkalosis

A condition caused by hyperventilation leading to a decrease in blood CO2 and an increase in blood pH.

Renal System

The body's system that adjusts bicarbonate concentration slowly but completely to regulate pH. adjusts [HCO-3]

pK

The negative logarithm of the dissociation constant which indicates the pH at which a buffer has maximum capacity.

pK = -logKD

Hypoventilation

A decrease in ventilation sufficient to increase the concentration of carbon dioxide in the blood. leads to acidosis

Hyperventilation

An increase in ventilation leading to a decrease in the concentration of carbon dioxide in the blood. leads to alkalosis

Metabolic Acidosis

A condition characterized by a decrease in blood pH due to an increase in H+ ions from non-respiratory causes.

Metabolic Alkalosis

A condition characterized by an increase in blood pH due to a loss of H+ ions or an excess of bicarbonate.

Dissociation Equilibrium Constant (KD)

A measure of the tendency of a compound to dissociate into its components in solution.

KD = [A-][H+]/[HA]

strong acids = high KD and strong bases = low KD

Chemical buffers in plasma

proteins- have a number of different pKs and can change pH over a wide range

Phosphate buffers- 1mM of plasma only, primary in cells, contributes largely to intracellular buffer capability

pH regulation through CO2 equation

pH = 6.10 + log[HCO-3]/0.0308 Pco2

O2 Dissociation Curve

Graph showing the relationship between the partial pressure of O2 and the saturation of hemoglobin.

Bohr Effect

The phenomenon where increased CO2 levels lead to decreased affinity of hemoglobin for O2.

Diffusion Distance

The distance gases must travel to move between alveoli and blood, typically about 1 µm.

Pulmonary Ventilation

The process of moving air in and out of the lungs.

Acidosis

A condition where the pH of blood is below 7.35.

Alkalosis

A condition where the pH of blood is above 7.44.

Atmospheric Pressure (PB)

The pressure exerted by the weight of the atmosphere, typically around 760 mmHg.

Interstitial Fluid PO2

The partial pressure of oxygen in the fluid surrounding cells, typically around 40 mmHg.

Saturation of Hemoglobin (SO2)

The percentage of available hemoglobin binding sites occupied by oxygen.

Hemoglobin Concentration

The amount of hemoglobin in the blood, typically 15 g/dL.

Acid-Base Regulation

The mechanisms the body uses to maintain pH within a narrow range.

Haldane Effect

The phenomenon where the binding of O2 to hemoglobin decreases its affinity for CO2.

Oxygen Consumption (VO2)

The rate at which oxygen is used by tissues, typically expressed in mL/min.

Qa calculated with Cos rate

Qa = Qco2/PaCo2(Pb (barometric pressure)-47)

and

PaCO2 = QcO2/Qa (Pb-47)

Alveolar gas equation

PaO2 = flO2 (mole fraction of gas inspired) x (Pb - 47 ) - 1/R x PaCO2

Co2 carried into blood from tissue to lung equations

Qco2 = Qa([Co2]v - [CO2]a)

Oxygen consumption equation

Qo2 = Qa([O2]a - [O2]v)

Hemoglobin and Oxygen

hemoglobin delivers oxygen to tissues, only dissolved )2 diffuses across membrane

Oxygen dissociation curve

sensitive to T, pH and [CO2]. exercise shifts T, pH and [CO2] resulting in more O2 delivery. Main mechanism of O2 delivery

Oxygen delivery to tissues

2% dissolved, 98% from hemoglobin. Continuous gradient of Po2 from blood to mitochondria. O2 diffuses down partial pressure gradients

Co2 carried in blood

dissolved CO2 reacts with H2O to make HCO-3. Dissociates into H and bicarbonate. Dissolved 10%, As HCO-3 85%, and carbamino compounds 5%

Alveoli

Small air sacs in the lungs where gas exchange occurs.

Surfactant

A lipoprotein that lowers surface tension and stabilizes alveoli, reduces the work of breathing

Pleural fluid

Fluid that reduces friction and connects the lungs to the chest wall. helps sliding of two surfaces and reduces friction. helps maintain lung volume

Tidal Volume (TV)

The amount of air inhaled or exhaled during normal respiration.

Inspiratory Reserve Volume (IRV)

The maximum amount of additional air that can be inhaled after a normal inhalation.

Expiratory Reserve Volume (ERV)

The maximum amount of additional air that can be exhaled after a normal exhalation.

Residual Volume (RV)

The amount of air remaining in the lungs after a forced exhalation. cannot be measure by spirometry

Vital Capacity (VC)

The maximum amount of air that can be exhaled after a maximum inhalation.

IRV + TV + ERV

Total Lung Capacity (TLC)

The total volume of air in the lungs after maximal inhalation.

IRV + TV + ERV + RV

Forced Vital Capacity (FVC)

The total volume of air that can be forcefully exhaled after full inhalation.

Alveolar ventilation (QA)

The flow of fresh air that reaches the alveoli and participates in gas exchange.

Qa = Ve (respiration rate) x (Vt - tidal volume - Vd(anatomic dead space) )

Respiratory exchange ratio (R)

The ratio of CO2 produced to O2 consumed during metabolism.

R = QCO2/QO2

Henry’s Law

Relates the concentration of a gas in liquid to its partial pressure.

[A] ( concentration of dissolved gas) = Alpha(a) (solubility of gas) x Pa (partial pressure of gas)

Dead space

The part of the respiratory system where gas exchange does not occur.

Bronchodilation

Widening of the bronchi, allowing for increased airflow.

Bronchoconstriction

Narrowing of the bronchi, which can reduce airflow.

Respiration rate (RR)

The number of breaths taken per minute.

Law of Laplace

A principle that describes the relationship between pressure, surface tension, and radius in alveoli, influencing their stability and inflation.

P (pressure) = 2 y( or T surface tension)/ r (radius)

Functional residual capacity (FRC)

The volume of air remaining in the lungs after a passive exhalation, which includes the residual volume and expiratory reserve volume.

RV + ERV

Pulmonary Ventilation

rate at which air moves out of lungs. increases 15 fold during exercise

Qv = RR x TV

Pulmonary fibrosis

stiff lungs

Reynolds number

predicts laminar or turbulent flow

Re = 2aV(average velocity)p(density of air)/n(viscosity) or 2aQv/A(area)n

above 2500 is turbulent and below 2000 is laminar

BTPS to STPD conversion

Vbtps = 1.2104 Vstpd

Microvascular Network

The network of small blood vessels that includes arterioles, capillaries, and venules, facilitating exchange.

Venoconstriction

The constriction of veins which helps to increase venous return to the heart.

Skeletal Pump

The mechanism by which contraction of skeletal muscles helps propel blood through the veins toward the heart.

Thoracic Pump

The pressure changes in the thorax during breathing that assist in returning blood to the heart.

Total Peripheral Resistance (TPR)

The overall resistance to blood flow within the circulatory system, primarily affecting blood pressure.

Arterial Compliance

The ability of arteries to expand and contract with blood pressure, influencing blood flow and pressure.

Long-term Blood Pressure Regulation

received input from intestines and kidneys and discards fluid and waste through skin, lungs and intestines and kidney

Net Filtration Pressure (NFP)

The difference between hydrostatic pressure and osmotic pressure that determines fluid movement in capillaries.

Vasodilation

dilatation of arteries which decreases resistance and increases blood flow to tissues.

Vasoconstriction

The narrowing of blood vessels, which increases resistance and decreases blood flow. reduction of arteries

strenuous exercise on CO

increases heart rate, cardiac contractility, causes vasoconstriction and vasodilation to optimize cardiac output during physical activity. ½ of circulating energy is from skeletal muscles

short term arterial pressure regulation (neurogenic control)

fast acting.Mediated by baroreceptors- aortic arch or carotid sinus stretch sensors. send signal to brain to adjust heart rate and vessel tone, maintaining blood pressure homeostasis.

Hormonal cardiac regulation

Intermediate, takes minutes to hours. RAA, ADH and ANP. Hormones adjust sodium concentrations to maintain water, all act on kidneys

RAA (Renin-Angiotensin-Aldosterone)

secrets enzyme renin by kidneys- decreases arteriolar pressure, decreases Na2+ concentration, renal sympathetic nerve system. renin cleaves angiotensinogen in blood

forms angiotensin 1 and 2- raises blood pressure, Na2+ reabsorbed to blood, increase blood volume

increases thirst and releases ADH

ADH

synthesized by hypothalamus, constricts blood vessels and reduces urine output. promotes reabsorption of water by the kidneys

ANP

expressed in response to atria stretch, stimulates salt and water excretion in kidneys to rid the body of the excess fluid and reduce pressure

Atrial Depolarization

Represented by the P wave in an ECG.

PR segment

Represents the AV nodal delay, allowing for atrial contraction.

QRS complex

Represents sequential depolarization of the ventricles.