18.3: Maintenance of Blood Pressure

Question 1

Short-term control of blood pressure is mediated by the nervous system and the endocrine system.

The sympathetic nervous system increases blood pressure via vasoconstriction and an increase in cardiac output. The parasympathetic nervous system decreases blood pressure through lowering cardiac output. Neural changes in blood pressure are mediated by the baroreceptor reflex arc and chemoreceptors. When the oxygen level decreases sharply, peripheral chemoreceptors trigger a rise in blood pressure. When the pH decreases, the central chemoreceptors trigger a rise in heart rate and blood pressure.

Thyroid hormone, epinephrine, and norepinephrine increase cardiac output. Epinephrine, norepinephrine, and angiotensin-II

Answer 1

Short-term control of blood pressure is mediated by the nervous system and the endocrine system.

• The sympathetic nervous system increases blood pressure via vasoconstriction and an increase in cardiac output. The parasympathetic nervous system decreases blood pressure through lowering cardiac output. Neural changes in blood pressure are mediated by the baroreceptor reflex arc and chemoreceptors. When the oxygen level decreases sharply, peripheral chemoreceptors trigger a rise in blood pressure. When the pH decreases, the central chemoreceptors trigger a rise in heart rate and blood pressure.
• Thyroid hormone, epinephrine, and norepinephrine increase cardiac output. Epinephrine, norepinephrine, and angiotensin-II

Question 2

Long-term control of blood pressure is mediated by the urinary system and the endocrine system.

• Aldosterone, antidiuretic hormone, and angiotensin-II increase blood volume. Atrial natriuretic peptide decreases blood volume.
• The urinary system directly controls blood pressure by increasing or decreasing the amount of water lost from the body as urine.

Answer 2

Long-term control of blood pressure is mediated by the urinary system and the endocrine system.

• Aldosterone, antidiuretic hormone, and angiotensin-II increase blood volume. Atrial natriuretic peptide decreases blood volume.
• The urinary system directly controls blood pressure by increasing or decreasing the amount of water lost from the body as urine.

Question 3

Hypertension

Hypotension

Answer 3

Hypertension, or high blood pressure, is defined as a systolic pressure over 140 mm Hg and/or a diastolic pressure over 90 mm Hg. Hypotension is a systolic pressure lower than 90 mm Hg and/or a diastolic pressure lower than 60 mm Hg.

Question 4

Which of the following hormones decreases heart rate, and thus cardiac output and blood pressure?

acetylcholine

angiotensin-II

epinephrine

norepinephrine

Answer 4

Which of the following hormones decreases heart rate, and thus cardiac output and blood pressure?

acetylcholine

angiotensin-II

epinephrine

norepinephrine