physiology Chp 15

What are the two main types of blood vessels?

Arteries and veins

What function do arteries serve in the cardiovascular system?

pressure reservoir to store pressure.

What is the primary role of veins?

Volume reservoir to store blood volume.

How is the diameter of arterioles regulated?

homeostatically adjustable/regulated

What mechanism controls blood flow into capillaries?

arteriole sphincters.

What happens when arteriole sphincters are constricted?

Diverts blood away from capillary beds.

What is the skeletal muscle pump?

The action of skeletal muscles squeezing veins to help move blood toward the heart.

What is the significance of valves in veins below the heart?

To ensure that blood moves unidirectionally upward toward the heart.

What occurs during ventricular contraction?

Major arteries swell as they receive an influx of blood, storing pressure.

What is mean arterial pressure (MAP)?

calculated as diastolic pressure plus one-third of pulse pressure and reflects average pressure driving blood into the arterioles.

What is systolic pressure?

The normal high pressure in the arteries during ventricular contraction.

What is diastolic pressure?

The normal low pressure in the arteries during ventricular relaxation.

What is pulse pressure?

The difference between systolic and diastolic pressure (S - D).

What factors influence blood pressure?

Cardiac output, arteriole resistance, total blood volume, and blood distribution.

How does the body make rapid adjustments to blood pressure?

Adjustments are made via changes in cardiac output and peripheral resistance.

What role do the kidneys play in blood pressure regulation?

make slower adjustments to blood volume, influencing blood pressure.

What is hemodynamics?

The study of fluid dynamics as applied to blood flow.

What happens to blood pressure as blood flows through the circulatory system?

Decreases

What is the relationship between mean arterial pressure and cardiac output?

Mean arterial pressure is proportional to both cardiac output and arteriole resistance.

What is the primary mechanism for regulating blood distribution?

Arteriole sphincter constriction

What is the effect of arterial elastic recoil?

Allows for steady blood flow from arteries to arterioles during ventricular relaxation.

What is the significance of elastic tissue in arteries and veins?

provides the ability to stretch and recoil, helping to maintain blood pressure.

What happens when sphincters to capillaries are open?

Blood flows into the capillary beds for exchange with the tissue.

What determines how easily blood moves from the arteries to the arterioles?

Arteriolar resistance

What are the two main influences on arteriolar resistance?

Local and systemic control mechanisms

What is myogenic autoregulation?

The automatic contraction of smooth muscle in response to being stretched

What happens to arteriole diameter when blood supply increases?

Arteriole diameter increases due to stretching of smooth muscle, leading to reflexive contraction and eventual decrease in diameter.

What types of signaling influence arteriolar diameter?

Paracrine and autocrine signaling

What neurotransmitter is primarily involved in sympathetic control of arteriolar resistance?

Norepinephrine

What effect does increased norepinephrine have on blood vessel diameter?

It causes vasoconstriction.

What is the role of epinephrine in arteriolar resistance?

Acts at β2-receptors to cause vasodilation.

What is hyperemia?

Locally increased blood flow.

What is active hyperemia?

Increased local blood supply in response to changing blood gas levels.

What is reactive hyperemia?

Increased blood flow that occurs after exertion.

What is the primary function of the cardiovascular system?

Transport.

What is the secondary function of the cardiovascular system?

Exchange of materials across capillary walls.

What type of cells make up the walls of capillaries?

Single layer of flattened endothelial cells.

What are the two pathways for material exchange in capillaries?

Para-cellular pathway and trans-cellular pathway.

What is bulk flow in the context of capillaries?

Mass movement of fluid into or out of capillaries due to pressure gradients.

What causes filtration in capillaries?

Hydrostatic pressure exceeding colloid osmotic pressure.

What causes absorption in capillaries?

Colloid osmotic pressure exceeding hydrostatic pressure.

What is edema?

Local fluid accumulation due to failure of filtered fluid to return to circulation.

What are two primary causes of edema?

Inadequate drainage of lymph and filtration far greater than absorption.

What is the leading cause of morbidity and mortality in the country?

Cardiovascular disease (CVD).

What are the major controllable risk factors for cardiovascular disease?

Smoking, obesity, sedentary lifestyle, untreated hypertension.

What is metabolic syndrome?

A chronic condition characterized by poor diet, lack of exercise, and other risk factors contributing to heart disease.

What is the role of baroreceptors in cardiovascular function?

They sense blood pressure and mediate fast increases in heart rate and peripheral resistance.

What happens to capillary flow velocity as total cross-sectional area increases?

Capillary flow velocity decreases.

What type of capillaries have many large pores for high rates of fluid exchange?

Fenestrated capillaries.

What is the relationship between capillary density and metabolic activity?

Capillary density is related to the metabolic activity of cells.