Blood Pressure Homeostasis and Circulatory Shock Flashcards

A set of vocabulary flashcards covering the homeostatic control of blood pressure, related medications, and the types and signs of circulatory shock based on Patton Ch 30 lecture notes.

Blood pressure

The pressure exerted by blood on the walls of the arteries.

Systolic pressure

The highest pressure in the arteries during systole.

Diastolic pressure

The lowest pressure in the arteries during diastole.

Sphygmomanometer

A mercury-filled instrument used to measure blood pressure by inflating a cuff to exceed systolic pressure and slowly releasing it to detect pulsing sounds.

Hypertension

A condition of sustained elevated arterial pressure of $140/90\,mmHg$ or higher.

Hypotension

Low blood pressure characterized by a systolic pressure below $100\,mmHg$.

Orthostatic hypotension

Temporary low blood pressure and dizziness when rising suddenly from a sitting or reclining position.

Pulse Pressure ($PP$)

The difference between systolic and diastolic pressure, calculated as $PP = SBP - DBP$.

Mean Arterial Pressure ($MAP$)

The average pressure in the arteries, calculated using the formula $MAP = \frac{SBP + 2(DBP)}{3}$.

Cardiac Output ($CO$)

One of the two primary factors determining blood pressure, calculated as $SV \times HR$.

Peripheral Resistance ($PR$)

The resistance to blood flow determined by blood vessel diameter, blood viscosity, and blood vessel length.

Vasomotor pressoreflexes

Reflexes involving baroreceptors in the aorta and carotid arteries that maintain homeostasis by altering heart rate and vessel dilation in response to blood pressure changes.

Vasomotor chemoreflexes

Reflexes involving chemoreceptors in the carotid and aortic bodies that detect $CO_2$, low $O_2$, or low $pH$ ($H^+$) to adjust heart rate and stroke volume.

RAAS (Renin-Angiotensin-Aldosterone System)

A long-term indirect renal mechanism where Renin leads to the formation of Angiotensin II, causing vasoconstriction and stimulating the secretion of Aldosterone and ADH.

Aldosterone

A hormone that causes $Na^+$ retention by the kidneys to increase blood volume and blood pressure.

Antidiuretic hormone (ADH)

A hormone from the posterior pituitary that promotes $H_2O$ retention by the kidneys to increase blood volume.

Atrial natriuretic peptide (ANP)

A chemical that decreases blood pressure by decreasing blood volume.

Nitric oxide (NO)

A potent vasodilator that causes a decrease in blood pressure.

ACE inhibitors

Antihypertensive medications that prevent the formation of Angiotensin II to prevent vasoconstriction and the release of ADH and Aldosterone.

Beta-blockers

Medications that calm the heart to lower blood pressure by reducing heart rate and stroke volume.

Chronotropic action

A term referring to the timing of the heart rate; positive chronotropic medications increase heart rate.

Inotropic action

A term referring to the power of cardiac contraction; negative inotropic medications decrease the force of contraction.

Digoxin

A drug with positive inotropic action that increases intracellular calcium to produce stronger cardiac contractions.

Atropine

A drug with positive chronotropic action that blocks parasympathetic (vagal) input to increase heart rate.

Calcium channel blockers

Drugs with negative inotropic and negative chronotropic action that reduce calcium entry into cardiac cells to decrease contractility and heart rate.

Circulatory shock

Inadequate blood flow to meet tissue needs, resulting in poor tissue perfusion, tissue damage, and signs such as tachycardia and low blood pressure.

Hypovolemic shock

A type of shock caused by reduced fluid volume, such as the loss of blood, plasma, or gastrointestinal fluids.

Cardiogenic shock

Shock caused by the reduced pumping of blood, as seen in heart failure.

Distributive shock

A category of shock where fluid is in the wrong compartment, often due to extreme vasodilation or leaky vessels; examples include Sepsis and Anaphylactic shock.

Sepsis

The most common cause of distributive shock, resulting from infection that makes blood vessels leaky, allowing fluid to move into the interstitium.