Tom Petty & The Heartbreakers

Question 1

In what organisms are open circulatory systems found?

Answer 1

Open circulatory systems are found in arthropods and most mollusks

Question 2

The closed vascular system contains:

Answer 2

arteries, capillaries, venules

Question 3

Arteries

Answer 3

carry blood away from the heart and branch into arterioles that feed the capillary beds

Question 4

Capillaries

Answer 4

the site of exchange between blood and tissue fluid

Question 5

Venules

Answer 5

drain the capillary beds and form veins, which deliver blood back to the heart

Question 6

Fish circulatory system

Answer 6

Atrium—receives blood from the body

Ventricle—receives pumped blood from the atrium and sends it to the gills

Blood from the gills collects in the aorta and is distributed throughout the body

Question 7

Where does the right atrium receive blood from?

Answer 7

The right atrium receives deoxygenated blood from the body from the superior and inferior vena cava

Question 8

Super and inferior vena cava

Answer 8

Superior vena cava—blood from upper body

Inferior vena cava—blood from lower body

Question 9

After the right atrium receives blood from the vena cava, where is it sent to?

Answer 9

The pulmonary artery pumps blood from the heart to the lungs,

Question 10

After blood is oxygenated in the lungs, where is it sent to?

Answer 10

oxygenated blood returns to the left atrium of the heart through the pulmonary veins

Question 11

In the mammalian heart: the right ventricle pumps blood through the ______ circuit, the left ventricle pumps blood through the ______ circuit

Answer 11

In the mammalian heart: the right ventricle pumps blood through the “pulmonary” circuit, the left ventricle pumps blood through the “systemic” circuit

Question 12

Why are valves needed in hearts?

Answer 12

Valves prevent backflow of blood

Question 13

What is the atrioventricular (AV) valve?

Answer 13

Atrioventricular (AV) valves lie between the atria and ventricles and prevent backflow when ventricles contract

Question 14

How do the pulmonary valve and aortic valve work together?

Answer 14

The pulmonary valve and aortic valve lie between the ventricles and the major arteries and prevent backflow when ventricles relax.

They are either both open or closed.

Question 15

Two phases of the cardiac cycle

Answer 15

Systole, when ventricles contract;
&
Diastole, when ventricles relax

In the cardiac cycle both sides of the heart contract at the same time—first the two atria contract, then the two ventricles

Question 16

How is heart muscle contraction coordinated?

Answer 16

Cells are in electrical contact with each other through gap junctions—spread of action potentials stimulates contraction in unison

Question 17

What are pacemaker cells?

Answer 17

Some cells in the heart are pacemaker cells and can initiate action potentials without input from the nervous system

Question 18

What are the primary pacemaker cells called?

Answer 18

The primary pacemaker cells are the sinoatrial node.

Question 19

Function of the sinoatrial node

Answer 19

An action potential is generated in the sinoatrial node.

The action potential spreads through gap junctions in the atria and they contract together, but it does not spread to the ventricles

Question 20

The action potential in the atria stimulates what node?

Answer 20

The action potential in the atria stimulates the atrioventricular node.

Question 21

the atrioventricular node.

Answer 21

The node consists of non-contracting cells that send action potentials to the ventricles via the bundle of His. Located inside right atriunm

Question 22

projection of the bundle of His

Answer 22

The bundle divides into right and left bundle branches that run to the tips of the ventricles.

Question 23

Why do heart muscles have longer contraction than skeletal muscles?

Answer 23

Much longer contractions (~300msec) compared to skeletal muscles.

Why?
To allow enough time for emptying and re-filling.

Question 24

How are action potentials in heart tissue different from neurons and other muscle cells?

Answer 24

Action potentials slow to rise, have broader plateau, slower to return to resting potential (which is unstable), compared to other muscle cells and neurons

Question 25

Why are capillaries adaptive for gas exchange?

Answer 25

Capillaries contribute an enormous surface area

Question 26

What is the difference in blood pressure between arteries and capillaries?

Answer 26

Blood pressure and flow through large arteries are high, and are lower through the capillaries.

Question 27

Why is pressure reduced in smaller vessels?

Answer 27

Pressure is reduced in smaller vessels because arterioles and capillaries are highly branched, presenting a large surface area.

Question 28

How do capillaries exchange molecules?

Answer 28

Capillary walls are a single layer of endothelial cells and have tiny holes called fenestrations.

Capillary beds are permeable to water, ions, and small molecules, but not to large proteins.

Question 29

How can the lining of arteries be damaged?

Answer 29

The lining of arteries can be damaged by high blood pressure, smoking, poor diet, or microorganisms

Question 30

What occurs in blood vessel disease?

Answer 30

In atherosclerosis, connective tissue and calcium deposits make the artery wall less elastic (wall is “hardened”), which can precipitate
a heart attack when the coronary arteries are involved.

Question 31

What is a thrombus?

Answer 31

A thrombus (blood clot) may form if platelets stick to the plaque;

Question 32

Embolus

Answer 32

A blood clot becomes an embolus if it breaks loose and moves in the bloodstream.

Question 33

Circulatory system in crawfish

Answer 33

A pump (heart) moves hemolymph through vessels to fluid-filled spaces in viscera.

Fluid returns to the heart through openings with valves—ostia.

Question 34

In closed circulatory systems, what is the relationship between blood and interstitial fluid?

Answer 34

In a closed circulatory system blood is kept separate from the interstitial fluid

Question 35

Advantages of closed circulatory systems:

Answer 35

1) Faster transport through vessels than through interstitial space

2) Blood can be directed to specific tissues by varying resistance (vasoconstriction
or vasodilation)

3) Specialized cells and molecules (nutrients, hormones) can travel in the vessels and be offloaded where needed

4) High pressure system facilitates efficient waste collection and excretion
(e. g. in vertebrate kidney)