Blood Vessels: Blood Pressure, Resistance, and Regulation Vocabulary

A set of vocabulary flashcards covering hemodynamics, resistance factors, mean arterial pressure, and nervous/hormonal regulation of blood pressure based on Chapter 20.

Blood Pressure

the force of blood pushing against the walls of the blood vessels

Systolic Blood Pressure (SBP)

Top number, pressure when the ventricle contract and pump blood out

Diastolic Blood Pressure (DBP)

bottom number, the pressure when the ventricles relax and fill with blood.

Pulse Pressure

The numerical difference between systolic and diastolic pressure, calculated as $\text{Pulse pressure} = \text{Systolic pressure} - \text{Diastolic pressure}$, which provides information regarding arterial elasticity.

Mean Arterial Pressure (MAP)

The average pressure pushing blood through the arteries during one complete cardiac cycle, calculated as $\text{MAP} = \text{Diastolic pressure} + \frac{1}{3}(\text{Systolic pressure} - \text{Diastolic pressure})$.

Venous Return

The volume and flow of blood returning back to the heart from the systemic capillaries.

Venous Valves

Folded structures within veins that prevent blood from flowing backward, ensuring unidirectional flow toward the heart.

Venous Tone

The baseline continuous contraction of smooth muscle in vein walls that narrows the vessel diameter to push blood toward the heart.

Skeletal Muscle Pump

A action where contracting skeletal muscles squeeze adjacent veins to drive blood toward the heart while internal valves prevent backflow.

Respiratory Pump

A mechanism assisting venous return where inhalation lowers intrathoracic pressure and increases intra-abdominal pressure, drawing blood up toward the heart.

Peripheral Resistance (TPR)

The total resistance to blood flow in the systemic blood vessels, influenced by blood viscosity, vessel length, and vessel radius.

Blood Viscosity

The relative thickness or friction-related stickiness of blood, where increased viscosity increases vascular resistance.

Blood Vessel Length

The cumulative distance blood must travel through vessels; increased length generates more cumulative friction, thereby raising resistance.

Blood Vessel Radius

The distance from the center of a blood vessel to its inner wall; small changes in radius exert the strongest effect on vascular resistance.

Lumen

The internal channel or hollow space inside a blood vessel through which blood flows.

Vasomotor Center

A cluster of sympathetic neurons in the medulla oblongata that regulates blood pressure by controlling blood vessel diameter.

Baroreceptors

Specialized stretch-sensitive sensory nerve endings in the carotid sinuses and aortic arch that detect blood pressure fluctuations.

Baroreceptor Reflex

An autonomic nervous reflex mechanism that counteracts acute shifts in blood pressure by altering heart rate, cardiac contractility, and vessel diameter.

Antidiuretic Hormone (ADH)

A hormone produced in the hypothalamus and released by the posterior pituitary that stimulates renal water reabsorption and triggers vasoconstriction at high concentrations.

Aldosterone

A steroid hormone secreted by the adrenal cortex that enhances renal sodium reabsorption and potassium secretion, expanding fluid volume and elevating blood pressure.

Angiotensin II

A potent vasoconstrictive peptide hormone that increases total peripheral resistance, stimulates aldosterone and ADH release, and activates the hypothalamic thirst center.

Angiotensin-Converting Enzyme (ACE)

An enzyme located primarily on blood vessel endothelium in the lungs that catalyzes the conversion of inactive Angiotensin I into active Angiotensin II.

Renin

An enzyme secreted by the kidneys in response to low blood pressure or sympathetic stimulation that cleaves angiotensinogen into angiotensin I.

Angiotensinogen

An inactive precursor plasma protein synthesized continuously by the liver and released into the bloodstream.

Atrial Natriuretic Peptide (ANP)

A hormone released by cardiac atrial cells in response to high blood volume stretch that promotes renal excretion of sodium and water, lowers blood pressure, and induces vasodilation.

Circulatory Shock

A critical condition caused by inadequate mean arterial pressure (MAP) leading to insufficient tissue perfusion, hypoxia, and impaired cellular waste removal.

Thrombus

A stationary blood clot formed within a blood vessel or heart chamber.

Embolus

An unattached mass (such as a detached blood clot) traveling through the bloodstream capable of occluding small blood vessels distant from its site of origin.