Chapter 20: The circulatory System: Blood Vessels and circulation

What are the three main categories of blood vessels?

Arteries, Veins, and Capillaries.

What is the primary function of arteries?

Arteries carry blood away from the heart.

What do veins do?

Veins carry blood toward the heart.

What are capillaries and their main role?

Capillaries are microscopic, thin-walled vessels that connect small arteries to small veins and are the site of material exchange.

What materials are exchanged in capillaries?

Gases, nutrients, wastes, hormones, etc.

How is blood flow defined?

Blood flow is the amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min).

What is the formula for blood flow?

Flow = Difference in pressure/Resistance (F = ΔP/R).

What is blood pressure?

Blood pressure is the force that blood exerts against the wall of a vessel.

What does systolic pressure represent?

Systolic pressure is the peak pressure recorded during ventricular systole.

What does diastolic pressure represent?

Diastolic pressure is the minimum arterial pressure measured during ventricular diastole.

What is the typical systolic and diastolic pressure values for a healthy adult?

Systolic pressure is about 120 mm Hg and diastolic pressure is about 75 mm Hg.

What is the pulse pressure and how is it calculated?

The difference between systolic and diastolic pressure; calculated as 120 - 75 = 45 mm Hg.

What is the mean arterial pressure (MAP) and how is it calculated?

MAP = diastolic pressure + 1/3 pulse pressure; for a typical adult, this is about 90 mm Hg.

How does gravity affect mean arterial pressure?

In standing individuals, MAP differs at various body levels, being lower in the head (about 62 mm Hg) and higher in the ankles (about 180 mm Hg).

What are some health complications caused by high blood pressure?

Heart attack, stroke, heart failure, aneurysm, and metabolic syndrome.

What happens to arteries as one ages that affects blood pressure?

Arteries become less distensible due to arteriosclerosis.

What is atherosclerosis?

The growth of lipid deposits in the walls of the arteries that can lead to rigidity and high blood pressure.

What is hypertension?

Chronic resting blood pressure higher than 140/90.

What is hypotension?

Chronic low blood pressure.

What three variables determine blood pressure?

Cardiac output, blood volume, and resistance to flow.

What are the three main factors affecting peripheral resistance?

Blood viscosity, vessel length, and vessel radius.

What are baroreceptors and where are they located?

Baroreceptors are sensors for blood pressure found in the aortic arch and carotid sinuses.

What effect do baroreceptors have if blood flow increases?

They cause a decrease in heart rate/cardiac output and induce vasodilation.

What role do chemoreceptors play in blood pressure regulation?

They detect oxygen, carbon dioxide, and pH levels, leading to vasoconstriction when oxygen is low or carbon dioxide is high.

How does aldosterone affect blood pressure?

Aldosterone promotes sodium and water retention in the kidneys, increasing blood volume.

What is venous return?

The flow of blood back to the heart.

What are the five mechanisms aiding venous return?

Pressure gradient, gravity, skeletal muscle pump, thoracic pump, and cardiac suction.