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Circulation and Gas Exchange Flashcards

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1
Q

Circulatory systems link exchange surfaces with

A

cells throughout the body.

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2
Q

Coordinated cycles of heart contraction drive

A

double circulation in mammals.

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3
Q

Patterns of blood pressure and flow reflect the structure and arrangement of

A

blood vessels.

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4
Q

Blood components function in

A

exchange, transport, and defense.

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5
Q

Gas exchange occurs across

A

specialized respiratory surfaces.

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6
Q

Breathing ventilates the

A

lungs

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7
Q

Adaptations for gas exchange include

A

pigments that bind and transport gases.

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8
Q

Why are gas exchange and circulation linked in multicellular organisms? What’s the deal for a unicellular organism?

A

direct transfer of materials between every cell and the environment is not possible. Instead multicellular rely on specialized systems that carry out exchange and the rest of the body;
Unicellular exchange occurs directly with the external environment

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9
Q

What’s going on with axolotl?

A

tiny blood vessels lie close to the surface of each filament in the gills. Across the surface, there is a net diffusion of O2 from the surrounding water into the blood and of CO2 from the blood into water. The short distances involved allow diffusion to be rapid. Pumping of the hear propels the o2 rich blood from the gill filaments to all other tissues of the body. There more short range exchange occurs, involving nutrients and o2 as well as co2 and other wastes

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10
Q

O2 and CO2 (and other small nonpolar molecules) can move between cells and their immediate surroundings by

A

diffusion

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11
Q

What are the limits of diffusion? How long does it take for a substance to diffuse from one point to another? Why does this put a substantial constraint on the body plan of any animal?

A

very slow for distances more than a few millimeters;
time it takes is proportional to the square of the distance;
Cannot diffuse as quickly as it needs to over big areas

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12
Q

Natural selection has resulted in two general solutions to the diffusion problem. What are they?

A

A body plan that places many or all cells in direct contact with the environment;
A circulatory system

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13
Q

How are the organisms the moon jelly Aurelia and the planarian Dugesia able to get nutrients (including oxygen) to their cells and get wastes (including carbon dioxide) away from their cells?

A

a central gastrovascular cavity functions in the distribution of substances through the body

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14
Q

What are the basic component of a circulatory system?

A

a circulatory fluid, a set of interconnecting vessels, and a muscular pump(the heart)

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15
Q

What is the basic structure of an open circulatory system? What is the circulatory fluid? Is it distinct from the interstitial fluid?

A

the circulatory fluid, called hemolymph, is also the interstitial fluid that bathes body cells; Heart contraction pumps the hemolymph through the circulatory vessels into interconnected sinuses, spaces surrounding the organs. Within the sinuses, chemical exchange occurs between the hemolymph and body cells. Relaxion of the heart draws hemolymph back in through pores, which are equipped with valves that close when the heart contracts

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16
Q

What are the advantages of an open circulatory system?

A

lower hydrostatic pressures make it less costly

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17
Q

What is the basic structure of a closed circulatory system? What is the circulatory fluid? Is it distinct from the interstitial fluid?

A

a circulatory fluid called blood is confined to vessels and is distinct from the interstitial fluid. One or more hearts pump blood into large vessels that branch into smaller ones that infiltrate the organs. Chemical exchange occurs between the blood and the interstitial fluid, as well as between the interstitial fluid and body cells

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18
Q

What are the advantages of a closed circulatory system?

A

high blood pressure, which enables the effective delivery of o2 and nutrients to the cells of larger and more active species; also well suited to regulating the distribution of blood to different organs

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19
Q

What is another term for the closed circulatory system of humans and other vertebrates?

A

cardiovascular system

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20
Q

What are the components of the cardiovascular system?

A

Arteries, veins, and capillaries

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21
Q

What distinguished veins from arteries?

A

Arteries carry blood from the heart to organs veins carry blood back to the heart

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22
Q

The hearts of all vertebrates contain two or more chambers. The chambers that receive blood entering the heart are called ________, and the chambers responsible for pumping blood out of the heart are called _________.

A

atria; ventricles

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23
Q

tell me about single circulation.

A

blood passes through the heart once in each complete circuit through the body

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24
Q

tell me about double circulation.

A

the pumps for the two circuits are combined into a single organ; one pump delivers oxygen poor blood to the capillary beds of the gas exchange tissues, where there is a net movement of O2 into the blood and of CO2 out of the blood; then this now oxygen rich blood enters the other pump contract of the heart propels this blood through the body

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25
Q

What is the overall organization of the mammalian cardiovascular system? What is the path of blood around the body?

A

Contraction of the right ventricle pumps blood to the lungs via the pulmonary arteries. As the blood flows through capillary beds in the left and right lungs, it loads O2 and unloads CO2. Oxygen rich blood returns from the lungs via the pulmonary veins to the left atrium of the heart.. Next O2 rich blood flows into the heart’s left ventricle via the aorta, which conveys blood to arteries leading thought the body. First branches to coronary arteries then to capillary beds in the head and arms. The aorta then depends into the abdomen, supplying o2 rich blood to the arteries leading to capillary beds in the abdominal organs and legs. With in the capillaries there is a net diffusion of o2 from the blood to the tissues and of CO2 into the blood. Capillaries rejoin, forming venues, which convey blood to veins. O2 poor blood from the head, neck and forelimbs is channeled into the superior vena cava vein. The inferior vena cave, drains blood from the trunk and hind limbs. they both empty their blood into the right atrium

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26
Q

What is the overall organization of the mammalian heart?

A

Located behind the sternum Size of a clenched fist and consists mostly of cardiac muscles. The two atria have relatively thin walls and serve as collection chambers of blood returning to the heart from the lungs or other body tissues. Much of the blood enters the atria flows into the ventricles while all heart chambers are relaxed. Remainder is transferred by contraction of the atria before the ventricles begin to contract.

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27
Q

What are the basics of a cardiac cycle?

A

When the heart contracts, it pumps blood; when it relaxes, its chambers fill with blood . one complete pumping and filling is the cardiac cycle

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28
Q

What is cardiac output? What are the two factors that determine cardiac output?

A

the volume of blood each ventricle pumps per minute; heart rate and stroke volume

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29
Q

Four valves in the heart prevent backflow and keep blood moving in the correct direction. What are these valves?

A 
2 Atrioventricular (AV) valve; 
2 Semilunar valves
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30
Q

steps involved in controlling heart rhythm.

A

Signals from SA node spread through atria; Signals are delayed at AV node; Bundle branches pass signals to heart apex; signals spread through ventricles

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31
Q

The heartbeat originates within the heart itself. What are autorhythmic cells?

A

they can contract and relax repeatedly without any signal from the nervous system

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32
Q

What is the sinoatrial node and what does it do?

A

Pacemaker, sets the rate and timing at which all cardiac muscle cells contract

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33
Q

What is the atrioventricular node and what does it do?

A

other autorhythmic cells ; delays the impulses for about .1 sec; this allows the atria to empty completely

34
Q

What are the walls of capillaries like?

A

Very thin walls, which consist of just an endothelium and a surrounding layer called basal lamina

35
Q

As blood passes from arteries to arterioles to capillaries, what is happening to the velocity of the blood? Why?

A

It slows because the number of capillaries is enormous; the total cross-sectional area is much greater in capillary beds than in the arteries

36
Q

What does decreased velocity of blood flow (along with the thin walls of the capillaries) have to do with what is happening in capillary beds?

A

the vessels generate substantial resistance to flow

37
Q

What is systolic pressure?

A

When the heart contracts

38
Q

What is diastolic pressure?

A

ventricles are relaxed

39
Q

What is pulse?

A

the rhythmic bulging of the artery walls with each heartbeat

40
Q

Relatively high blood pressure is responsible for the movement of blood through arteries. But, blood pressure in veins is relatively

A

low

41
Q

What are the mechanisms that assist with the return of venous blood to the heart?

A

valves help maintain the unidirectional flow

42
Q

What’s the deal with smooth muscle in veins?

A

smooth muscles in the walls of venues and veins contract during exercise to help keep the unidirectional flow

43
Q

What’s the deal with exercise and skeletal muscle in veins?

A

if you stop exercising abruptly; the muscles stop contracting and not enough blood can return to the heart

44
Q

Blood pressure is very low in capillary beds, and capillaries lack

A

smooth muscle.

45
Q

What regulates blood flow through capillary beds?

A

constriction or dilation of the arterioles that supply capillary beds; or pre capillary sphincters

46
Q

What’s the deal with fluid exchange between capillaries and the interstitial fluid?

A

blood pressure tends to drive fluid out of the capillaries, and the presence of blood proteins tends to pull fluid back

47
Q

If there is a net loss of fluid from capillaries, what happens to it?

A

the lost fluid and proteins return to the blood via the lymphatic system

48
Q

What is the lymphatic system?

A

includes a network of tiny vessels intermingled among capillaries of the cardiovascular system, as well as larger vessels into which small vessels empty

49
Q

What is lymph?

A

the fluid lost by capillaries after it enters the lymphatic system by diffusion

50
Q

What are lymph nodes and what do they do?

A

small, lymph-filtering organs which play an important role in the body defense;

51
Q

Blood is composed of about 55% plasma and 45%

A

cellular elements.

52
Q

What are the components of plasma and what are their functions?

A

ions and proteins that, together with the blood cells, function in osmotic regulation, transport, and defense

53
Q

What are the cellular elements of blood and what are their functions?

A

leukocytes (white blood cells)- defense and immunity
platelets- blood clotting
erythrocytes (red blood cells)- transport o2 and some co2

54
Q

Cellular elements of blood have limited life spans. Where do new cells come from?

A

stem cells

55
Q

Cholesterol travels in blood plasma mainly in particles that consist of thousands of

A

cholesterol molecules and other lipids bound to a protein.

56
Q

What is low-density lipoprotein (LDL) and what does it do?

A

delivers cholesterol to cells for membrane production

57
Q

What is high-density lipoprotein (HDL) and what does it do?

A

scavenges excess cholesterol for return to the liver

58
Q

What’s the deal if your ratio of LDL to HDL is high?

A

individuals with a high ratio of LDL to HDL are at substantially increased risk for atherosclerosis

59
Q

What is atherosclerosis?

A

the hardening of the arteries by accumulation of fatty deposits

60
Q

What is a heart attack (myocardial infarction)?

A

the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries

61
Q

What is a stroke?

A

the death of nervous tissue in the brain due to lack of O2

62
Q

Why do people take statins to reduce the risk of cardiovascular disease?

A

they can lower LDL levels and thereby reduce the risk of heart attack

63
Q

Why do people take aspirin to reduce the risk of cardiovascular disease?

A

inflammation plays a central role in atherosclerosis and thrombus formation and aspirin inhibits the inflammatory response

64
Q

Why do people control blood pressure to reduce the risk of cardiovascular disease?

A

chronic high blood pressure damages the endothelium that lines the arteries, promoting plaque formation

65
Q

What are the parts of the mammalian respiratory system pharynx, larynx, trachea, bronchus,bronchiole, diaphragm, nasal cavity

A

nasal cavity and pharynx- where air is inhaled
larynx- tips the epiglottis of the glottis so food goes down the esophagus
trachea- wind pipe
bronchi- trachea branches into two of these each one leading to the lung
bronchioles- within the lung the bronchi branch into these
alveoli- where gas exchange occurs

66
Q

Where exactly is gas exchange happening?

A

alveoli

67
Q

What is the surface area of alveoli like compared to the surface area of the skin?

A

it is 50 times that of the skin

68
Q

What protects alveoli from contamination?

A

white blood cells patrol the alveoli, engulfing foreign particles

69
Q

Mammals employ negative pressure breathing. What’s happening here?

A

pulling, rather than pushing, air into their lungs; using muscle contraction to actively expand the thoracic cavity

70
Q

What happens when the diaphragm moves down and the rib cage expands?

A

inhalation

71
Q

Involuntary mechanisms ensure that gas exchange is coordinated with

A

blood circulation and with metabolic demand.

72
Q

Describe the chart with medulla and blood ph

A

As CO2 level increases in the blood, pH gets lower. This is detected in the cerebrospinal fluid that surrounds the brain and spinal cord by the medulla. Ventilation increases and CO2 level decreases, raising blood pH.

73
Q

This control of breathing is in response to the level of CO2 in the blood and blood pH. Can blood O2 level have an effect on breathing? What’s the connection between the aorta/carotid sensors and breathing control centers in the brain?

A

o2 usually has little effect; when the o2 level drops very low, o2 sensors in the aorta and the carotid arteries in the neck send signals to the breathing control centers, which respond by increasing the breathing rate

74
Q

Blood flowing through the alveolar capillaries has lower PO2 and higher PCO2 than air in the alveoli. What’s going to happen?

A

net diffusion of o2 down its partial pressure gradient from the air in the alveoli to the blood

75
Q

Blood flowing through the systemic capillaries has higher PO2 and lower PCO2 than body tissue cells. What’s going to happen?

A

net diffusion of o2 out of the blood and co2 into the blood

76
Q

O2 is not really very soluble in water (and thus in blood), which poses a problem for animals that rely on the circulatory system to deliver O2. What is the animal’s answer to this problem?

A

animal transport most of their o2 bound to proteins called respiratory pigments

77
Q

What is the respiratory pigment of almost all vertebrates and many invertebrates?

A

hemoglobin

78
Q

Where is hemoglobin located in vertebrates?

A

contained in erythrocytes (red blood cells)

79
Q

What is a hemoglobin molecule like?

A

has four subunits (polypeptide chains), each with a cofactor called a heme group that has an iron atom at its center

80
Q

How is O2 transported by hemoglobin?

A

each iron atom binds one molecule- thus each hemoglobin can care 4 o2 molecules

81
Q

What causes O2 to be released from hemoglobin in the systemic capillaries?

A

the production of co2 during cellular respiration promotes the unloading of o2

82
Q

How is CO2 transported from the interstitial fluid surrounding tissues to the lungs and into the alveolar spaces?

A

through plasma into erythrocytes

Biology (21 decks)

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