Regulation of Mean Arterial Pressure (MAP)

Vocabulary flashcards covering key terms involved in neural and hormonal regulation of mean arterial pressure, blood oxygen, and pH.

Mean Arterial Pressure (MAP)

The average pressure in the aorta that drives blood through the systemic circuit.

Baroreceptor

Pressure-sensing receptor located in vessel walls that detects changes in blood pressure.

Chemoreceptor

Receptor that senses chemical changes—primarily blood O₂ and H⁺ (pH) levels.

Medulla Oblongata

Brainstem region that integrates baro- and chemoreceptor input and coordinates cardiovascular reflexes.

Integrating Center

The processing site (medulla) that compares sensory data to set points and issues efferent commands.

Aortic Arch Baroreceptors

Baroreceptors embedded in the aortic arch wall, directly monitoring MAP.

Carotid Sinus Baroreceptors

Pressure receptors in the dilated portion of the common carotid arteries; back-up MAP monitors for cerebral perfusion.

Venous Baroreceptors (Volume Receptors)

Low-pressure receptors at the vena cava–right atrium junction that gauge total blood volume.

Vagus Nerve (Cranial Nerve X)

Carries sensory signals from aortic arch baro-/chemoreceptors and parasympathetic output to the heart.

Glossopharyngeal Nerve (Cranial Nerve IX)

Transmits sensory input from carotid sinus baro-/chemoreceptors to the medulla.

Cardiac Control Center

Medullary nuclei that regulate heart rate and contractility.

Cardiac Accelerator Center (CAC)

Sympathetic subdivision that speeds the heart and boosts contractility.

Cardiac Inhibitory Center (CIC)

Parasympathetic subdivision that slows heart rate via the vagus nerve.

Vasomotor Center

Medullary nuclei that adjust blood vessel diameter.

Vasoconstrictor Center

Sympathetic neurons that increase vascular smooth-muscle tone, raising resistance.

Vasodilator Center

Neuronal group that reduces sympathetic tone, promoting vessel dilation.

Sympathetic Cardiac Nerves

Efferent fibers that elevate heart rate and contractility when activated.

Parasympathetic Vagus Output

Efferent pathway that decreases heart rate when activated.

Total Peripheral Resistance (TPR)

Sum of systemic vascular resistance; major determinant of MAP.

Baroreceptor Reflex

Rapid negative-feedback loop that adjusts heart and vessel activity to correct MAP deviations.

Chemoreceptor Reflex

Response that alters cardiovascular output to correct blood O₂ or pH abnormalities.

Catecholamines

Hormones (epinephrine, norepinephrine) released by adrenal medulla during sympathetic activation.

Norepinephrine (NE)

Primary sympathetic neurotransmitter that binds mainly α₁ receptors to induce vasoconstriction.

Epinephrine (Epi)

Adrenal hormone that binds β₁ to stimulate the heart and β₂ to dilate skeletal/cardiac muscle vessels.

α₁-Adrenergic Receptor

Receptor on most systemic vessels that mediates vasoconstriction when stimulated by NE or Epi.

β₁-Adrenergic Receptor

Receptor on cardiac muscle that increases heart rate and contractility when activated.

β₂-Adrenergic Receptor

Receptor on skeletal- and cardiac-muscle vessels and airways that triggers vasodilation/bronchodilation when bound by epinephrine.

Fight-or-Flight Redistribution

Sympathetic pattern that constricts most vessels (α₁) while dilating those to heart & skeletal muscle (β₂).

Proprioceptor Input

Joint-movement signals that alert the medulla to physical activity and pre-emptively raise MAP.

Set Point

The target value for a physiological variable (e.g., normal MAP, O₂, pH) used for feedback comparison.

Cardiac Output (CO)

Volume of blood pumped by the heart per minute; product of heart rate and stroke volume.

Vasomotor Nerves

Sympathetic fibers that innervate vascular smooth muscle to regulate vessel tone.

Antidiuretic Hormone (ADH)

Posterior-pituitary hormone that promotes renal water reabsorption and acts as a vasoconstrictor to raise MAP.

Angiotensin II

Potent vasoconstrictor hormone formed in the renin–angiotensin pathway; elevates MAP and stimulates aldosterone.

Aldosterone

Adrenal cortical hormone that increases Na⁺ and water reabsorption to expand blood volume.

Atrial Natriuretic Peptide (ANP)

Cardiac hormone that promotes vasodilation and renal Na⁺/water loss, lowering blood volume and MAP.

Blood Volume Regulation

Kidney-mediated adjustments of water excretion that influence venous return and MAP.