Chapter 1 Overview over cardiovascular system

Question 1

The vagus nerve innervates the SA node. What neurotransmitter is released to the cardiac cells and what receptor are they attaching to?

Answer 1

Acetylcholine. Muscarinic receptors.

Question 2

What phenomenon is called Starling’s law of the heart?

Answer 2

Stroke volume increases in proportion with end-diastolic volume of the heart

Question 3

T/F The walls of veins have smooth muscle cells?

Answer 3

True

Question 4

The cells must draw their nutrients from and relate their products into the interstitial fluid, which is the immediate environment of individual cells. However, the interstitial fluid cannot be considered a large reservoir for nutrients or a large sink for metabolic products. Why?

Answer 4

The volume of the interstitial fluid is less than half that of the cells which it serves

Question 5

List 3 conditions, provided by the cardiovascular system, that are essential for regulating the composition of interstitial fluid by the process of diffusion

Answer 5

1. There must be adequate blood flow through the tissue capillaries
2. The chemical composition of the arterial blood must be controlled to be that which is optimal in the interstitial fluid
3. diffusion distances between plasma and tissue cells must be short

Question 6

Diffusion is a poor mechanism for moving substances from an organ to another organ that is 1m or more distant. Which process should be used for transportation?

Answer 6

Convection.

Substances easily move along with blood flow because they are either dissolved or contained within blood

Question 7

These three organs are where blood flows solely to supply the metabolic needs of the tissue. They do not recondition the blood for the benefit of any other organ.

Answer 7

Brain
Heart
and Skeletal muscles

Question 8

• What is the molecule released by sympathetic nerves and what are the receptors involved ?
• effect on arterioles?
• effect on veins/ venules ?

Answer 8

• Release of norepinephrine acting on apha-adrenergic receptors
• arterioles : vasoconstriction : increase of vascular resistance, decrease of blood flow
• veins/ venules ? venoconstriction => decrease of venous volume => increase of venous return and therefore of cardiac filling => Starling law : increase of cardiac output