Week 3: Blood Pressure & Homeostasis

A comprehensive set of vocabulary flashcards covering key terms, hormones, reflexes, pathological states, and physiological principles related to blood pressure regulation and cardiovascular homeostasis.

Blood Pressure (BP)

The force exerted by blood against a vessel wall as it flows through the circulatory system.

Flow

The volume of blood moving through a vessel, organ, or tissue per unit time.

Perfusion

Blood flow per given mass or volume of tissue; reflects delivery of oxygen and nutrients.

Systolic Pressure

Arterial pressure recorded during ventricular contraction (the top number in BP).

Diastolic Pressure

Arterial pressure recorded when the heart is relaxed between beats (the bottom number).

Pulse Pressure

The difference between systolic and diastolic pressures; indicator of arterial health.

Mean Arterial Pressure (MAP)

Average arterial pressure during one cardiac cycle; calculated as (systolic–diastolic)/3 + diastolic.

Hypertension

Chronic resting blood pressure > 140/90 mmHg.

Hypotension

Chronically low resting blood pressure below normal levels.

Arteriosclerosis

Age-related stiffening and loss of elasticity in arterial walls.

Atherosclerosis

Accumulation of lipid and calcium deposits in arterial walls, producing hard, narrowed arteries.

Peripheral Resistance

Opposition blood encounters in peripheral vessels; governed by viscosity, vessel length, and radius.

Blood Viscosity

Thickness of blood determined mainly by red blood cells and plasma proteins.

Vasodilation

Widening of a blood vessel’s radius, decreasing resistance and lowering BP.

Vasoconstriction

Narrowing of a blood vessel’s radius, increasing resistance and raising BP.

Cardiac Output (CO)

Volume of blood pumped by the ventricles each minute; heart rate × stroke volume.

Stroke Volume

Amount of blood ejected by each ventricle in a single beat.

Heart Rate

Number of heartbeats per minute.

Blood Volume

Total quantity of blood circulating in the body.

Renin-Angiotensin-Aldosterone System (RAAS)

Kidney-initiated hormonal pathway that raises blood volume and pressure.

Angiotensin II

Potent vasoconstrictor that increases thirst and stimulates aldosterone release.

Aldosterone

“Salt-retaining” hormone that promotes renal sodium and water reabsorption, raising blood volume.

Natriuretic Peptides (ANP)

Cardiac hormones that promote sodium and water excretion, lowering blood volume and pressure.

Antidiuretic Hormone (ADH, Vasopressin)

Hormone that causes kidneys to reabsorb water, increasing blood volume and pressure.

Catecholamines (Epinephrine & Norepinephrine)

Adrenal medulla hormones that stimulate vasoconstriction and raise BP.

Autoregulation

Tissue’s ability to adjust its own blood supply through local mechanisms.

Vasomotor Center

Region of the medulla that regulates vessel diameter via autonomic reflexes.

Baroreflex

Reflex responding to arterial stretch to stabilize blood pressure.

Chemoreflex

Reflex adjusting circulation in response to blood pH, CO₂, and O₂ levels.

Medullary Ischemic Reflex

Autonomic response to reduced brainstem perfusion that elevates blood pressure.

Vasoactive Chemicals

Locally released substances (e.g., histamine, prostaglandins) that alter vessel diameter.

Angiogenesis

Growth of new blood vessels, often triggered by hypoxic tissues.

Capillary Hydrostatic Pressure

Blood pressure within capillaries that drives fluid filtration into tissues.

Colloid Osmotic Pressure

Osmotic pull exerted by plasma proteins drawing fluid back into capillaries.

Diffusion (Capillary Exchange)

Passive movement of small molecules down concentration gradients across capillary walls.

Transcytosis

Vesicular transport of large molecules across endothelial cells.

Filtration

Movement of fluid out of capillaries at the arterial end driven by hydrostatic pressure.

Reabsorption

Return of fluid into capillaries at the venous end driven by osmotic pressure.

Venous Return

The flow of blood back to the heart via veins.

Venous Valves

Flaplike structures in veins that prevent backflow of blood.

Skeletal Muscle Pump

Compression of veins by contracting muscles, propelling blood toward the heart.

Respiratory Pump

Pressure changes during breathing that move venous blood toward the heart.

Gravity (Venous Return)

Effect that allows blood from the head and neck to flow downward to the heart.

Thrombus

A stationary blood clot attached to a vessel wall.

Embolus

A traveling clot or fragment that can lodge in smaller vessels.

Transient Ischemic Attack (TIA)

Brief interruption of cerebral blood flow causing temporary stroke-like symptoms without lasting damage.

Cerebrovascular Accident (CVA, Stroke)

Sudden loss of brain function due to prolonged ischemia or hemorrhage.

Ischemic Stroke

Stroke caused by clot-induced blockage of a cerebral vessel (≈80 % of cases).

Hemorrhagic Stroke

Stroke caused by rupture of a cerebral vessel leading to bleeding within or around the brain.

Circulatory Shock

State in which cardiac output is insufficient to meet metabolic needs.

Cardiogenic Shock

Shock resulting from inadequate cardiac pumping, often after myocardial infarction.

Low Venous Return (LVR) Shock

Shock due to insufficient blood returning to the heart.

Hypovolemic Shock

Most common LVR shock; produced by blood or fluid loss from hemorrhage, burns, or dehydration.

Obstructed Venous Return Shock

Shock caused by a physical blockage compressing a vein and impeding flow.

Venous Pooling Shock

Shock in which normal blood volume gathers in lower limbs, reducing return to the heart.

Neurogenic Shock

Form of venous pooling shock due to loss of vasomotor tone after brainstem injury or emotional stress.

Septic Shock

Shock from bacterial toxins that induce vasodilation and increased capillary permeability.

Anaphylactic Shock

Severe allergic reaction causing widespread vasodilation and capillary leakage.

Edema

Accumulation of excess fluid in interstitial spaces, often impairing tissue function.