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Biology 20 > Human Systems - Part 2 > Flashcards

Human Systems - Part 2 Flashcards

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1
Q

The circulatory system:

A

The circulatory system is a complex transport system consisting of the heart, a network of blood vessels and blood.

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2
Q

The main functions of the circulatory system are:

A
  1. Transport of respiratory gases, hormones, nutrients and wastes. 2. Regulation of body temperature. 3. Protection from blood loss and disease.
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3
Q

The heart:

A

The heart is a muscular organ that pumps blood throughout the body. The muscle tissue of the heart is composed of cardiac muscle cells.

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4
Q

The mammalian heart has ____ chambers.

A

four

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5
Q

Atria:

A

The atria are the thin-walled, upper chambers of the heart.

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6
Q

The right atrium:

A

The right atrium collects deoxygenated blood from the body and moves it into the right ventricle.

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7
Q

The left atrium:

A

The left atrium collects oxygenated blood from the lungs and moves it into the left ventricle.

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8
Q

Ventricles:

A

The ventricles are the thick-walled, lower chambers of the heart.

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9
Q

The right ventricle:

A

The right ventricle collects blood from the right atrium and pumps it out of the heart towards the lungs.

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10
Q

The left ventricle:

A

The left ventricle collects blood from the left atrium and pumps it out towards the body. The left ventricle has thicker walls than the right ventricle because it must contract with more force in order to pump blood out to all the parts of the body.

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11
Q

The septum (heart):

A

The septum is a muscular wall that separates the right atrium and right ventricle from the left atrium and left ventricle. The septum is thicker between the ventricles because the ventricle contract with more force than the atria.

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12
Q

Venae cavae:

A

The venae cavae are blood vessels that carry deoxygenated blood from the body into the right atrium.

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13
Q

The superior vena cava:

A

The superior vena cava carries blood from the head, arms and chest into the right atrium.

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14
Q

The inferior vena cava:

A

The inferior vena cava carries blood from the lower part of the body into the right atrium. The inferior vena cava is the largest vein in the human body.

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15
Q

The aorta:

A

The aorta carries oxygenated blood from the left ventricle towards the body. The aorta is the largest artery in the human body.

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16
Q

The pulmonary arteries:

A

The pulmonary arteries carry deoxygenated blood from the right ventricle of the heart to the lungs to be oxygenated.

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17
Q

The left pulmonary artery:

A

The left pulmonary artery carries blood to the left lung.

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18
Q

The right pulmonary artery:

A

The right pulmonary artery carries blood to the right lung.

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19
Q

The pulmonary veins:

A

The pulmonary veins carry oxygenated blood from the lungs into the left atrium of the heart.

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20
Q

The left pulmonary veins:

A

The left pulmonary veins carry blood from the left lung.

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21
Q

The right pulmonary veins:

A

The right pulmonary veins carry blood from the right lung.

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22
Q

Coronary arteries:

A

Coronary arteries branch off of the aorta and carry oxygenated blood to the cells of the heart.

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23
Q

Coronary veins:

A

Coronary veins transport deoxygenated blood from the cells of the heart into the right atrium.

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24
Q

The atrioventricular (AV) valves:

A

The atrioventricular (AV) valves allow blood to flow from the atria to the ventricles and prevent the backflow of blood from the ventricles to the atria.

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25
Q

The right atrioventricular valve:

A

The right atrioventricular valve, also called the tricuspid valve, controls blood flow between the right atrium and the right ventricle.

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26
Q

The left atrioventricular valve:

A

The left atrioventricular valve, also called the bicuspid valve, controls blood flow between the left atrium and the left ventricle.

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27
Q

Chordae tendinae:

A

Strong, string-like tendons called chordae tendinae attach the atrioventricular valves to papillary muscles in the walls of the ventricles. The chordae tendinae prevents the valves from inverting.

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28
Q

The semilunar valves:

A

The semilunar valves allow blood to flow from the ventricles to the aorta and the pulmonary arteries, preventing the backflow of blood.

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29
Q

The pulmonary semilunar valve:

A

The pulmonary semilunar valve controls blood flow from the right ventricle to the pulmonary trunk, which connects to the pulmonary arteries.

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30
Q

The aortic semilunar valve:

A

The aortic semilunar valve controls blood flow from the left ventricle to the aorta.

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31
Q

Arteries:

A

Carry blood away from the heart.

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32
Q

Arterioles:

A

Arterioles are smaller arteries that branch off of larger arteries.

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33
Q

Capillaries:

A

Connect arterioles to venules; site of nutrient and gas exchange between the blood and body cells.

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34
Q

Veins:

A

Carry blood towards the heart.

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35
Q

Venules:

A

Smaller veins that branch off of larger veins.

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36
Q

Arteries have _____ distinct layers.

A

three

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37
Q

The outer layer of an artery consists of…

A

connective tissue and elastic tissue.

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38
Q

The middle layer of an artery:

A

The middle layer consists of elastic tissue and smooth muscle tissue. This middle layer is much thicker in arteries than in veins.

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39
Q

The inner layer of an artery:

A

The inner layer is primarily composed of connective tissue.

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40
Q

Why do arteries have thick elastic walls?

A

Arteries have thick, highly elastic walls because they carry high-pressure blood coming from the heart.

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41
Q

How do ventricles affect blood flow in arteries?

A

The ventricles of the heart contract with significant force, so the blood in the arteries exerts significant pressure on the walls of the arteries. As the ventricles of the heart contract, the walls of the arteries expand as blood is forced through and recoil as the ventricles relax. This expansion and recoil provide additional pumping action to keep blood flowing in the right direction. Artery expansion can be felt as a pulse at various points in the body.

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42
Q

Capillaries are the (smallest/largest) blood vessels in the body.

A

smallest

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43
Q

Capillaries are arranged in networks called _________ ____. The walls of capillaries are ___ cell layer thick. The diameter inside a capillary is just large enough for blood cells to travel through ______ ____. Blood pressure is _____ in capillaries than in arteries.

A

capillary beds, one, single file, lower

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44
Q

Capillaries are the site of exchange between the…

A

blood and the cells of the body.

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45
Q

Almost every cell in the body is in direct contact with a _________. Oxygen and nutrients move from blood in the capillaries into the _____ of the body. Carbon dioxide and wastes move from the cells of the body into the blood in the ___________.

A

capillary, cells, capillaries

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46
Q

The exchange that happens at the capillary level is vital for the functioning of other human body systems. Capillaries are the site of gas exchange in the _______ of the lungs. Capillaries in the _____ of the small intestine allow for the absorption of nutrients from food. Capillaries provide the ______ for and remove the ______ ________ from muscle cells. Capillaries play an important role in the filtering of blood in the _________ system.

A

alveoli, villi, oxygen, carbon dioxide, excretory

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47
Q

The amount of blood flowing through a capillary is controlled depending on…

A

the needs of particular cells at any given time.

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48
Q

When cells have lower metabolic needs, blood can bypass the capillary through the action of ____________ __________.

A

precapillary sphincters

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49
Q

When a precapillary sphincter is (closed/open), blood will be shunted directly from the arteriole to the venule.

A

closed

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50
Q

Veins have _____ distinct layers.

A

three

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51
Q

The outer layer of veins:

A

The outer layer consists of connective tissue and elastic tissue.

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52
Q

The middle layer of veins:

A

The middle layer consists of elastic tissue and smooth muscle tissue. This middle layer is much thinner in veins than in arteries.

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53
Q

The inner layer of veins:

A

The inner layer is primarily composed of connective tissue.

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54
Q

The walls of veins are _______ than arteries and the diameter is ______ than arteries.

A

thinner, larger

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55
Q

Blood pressure is lowest in _____, so thick, muscular walls are not necessary.

A

veins

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56
Q

What do veins use to keep blood flowing to the heart?

A

Veins use skeletal muscles and one-way valves to keep blood flowing toward the heart.

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57
Q

How does skeletal muscle aid in blood circulation in veins?

A

Contraction of skeletal muscles next to veins pushes blood past a one-way valve. As the muscles relax, the one-way valve behind the blood closes, preventing the backflow of blood.

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58
Q

Vasodilation:

A

Vasodilation is the widening of blood vessels due to the relaxation of smooth muscles in the blood vessels. When the internal environment of the body is too warm, vasodilation of blood vessels near the surface of the skin allows more heat to dissipate from the blood into the environment.

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59
Q

Vasoconstriction:

A

Vasoconstriction is the narrowing of blood vessels due to the contraction of smooth muscles in the blood vessels. When the internal environment of the body is too cold, vasoconstriction of blood vessels near the surface of the skin prevents heat loss from the blood to the environment.

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60
Q

Myogenic Muscle:

A

Cardiac muscle is called myogenic muscle because it has the ability to contract without external nervous stimulation.

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61
Q

The strength and rate of the heartbeat are under ___________ control of the nervous system.

A

involuntary

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62
Q

The sinoatrial (SA) node:

A

The sinoatrial (SA) node generates an electrical signal that stimulates the simultaneous contraction of the atria. The SA node is referred to as the pacemaker of the heart because it sets the rhythm of the heart at about 70 beats per minute (bpm).

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63
Q

The atrioventricular (AV) node:

A

As the atria contract, the electrical signal is transmitted to the atrioventricular (AV) node. The impulse is delayed at the AV node to allow time for the ventricle to fill with blood.

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64
Q

Bundle of His:

A

The bundle of His transmits the signal through the left and right bundle branches that divide into the Purkinje fibres.

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65
Q

The Purkinje fibres:

A

The Purkinje fibres stimulate the simultaneous contraction of the ventricles.

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66
Q

How is the “Lubb-dubb” sound made?

A

As the ventricles contract, the AV valves are forced shut, producing the “lubb” sound. As the ventricles relax, the pulmonary and aortic semilunar valves close, producing the “dubb” sound.

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67
Q

The cardiac cycle can be divided into two main phases —

A

diastole and systole.

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68
Q

Diastole:

A

Diastole refers to the period of time when the ventricles are relaxed and the heart is filling with blood.

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69
Q

Systole:

A

Systole refers to the periods of time in which the ventricles are contracting.

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70
Q

Blood pressure:

A

Blood pressure is a measure of the force exerted by blood on the walls of the arteries.

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71
Q

Where is blood pressure measured and why? What is used?

A

Blood pressure is measured in arteries because the pressure is highest in the arteries. It is measured using a sphygmomanometer.

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72
Q

The coronary pathway:

A

The coronary pathway involves the transport of blood to and from the cells of the heart itself.

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73
Q

The pulmonary pathway:

A

The pulmonary pathway involves the transport of blood from the heart to the lungs and back.

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74
Q

The systemic pathway:

A

The systemic pathway involves the transport of blood from the heart to the body and back.

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75
Q

Systolic pressure:

A

Systolic pressure is the pressure in arteries when the ventricles are contracting.

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76
Q

Diastolic pressure:

A

Diastolic pressure is the pressure in arteries when the ventricles are relaxed.

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77
Q

The four main components of blood are:

A

Plasma, erythrocytes (red blood cells), leukocytes (white blood cells) and platelets

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78
Q

Blood components can be separated by mass using a __________.

A

centrifuge

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79
Q

Plasma:

A

The liquid portion of blood. Plasma makes up approximately 55% of blood volume. Plasma contains about 90% water and 10% dissolved substances, such as proteins, lipids, glucose, gases and salts (electrolytes). Examples of plasma proteins include hormones, enzymes, antibodies and fibrinogens involved in blood clotting.

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80
Q

The water in plasma allows it to help maintain homeostasis by:

A

Having viscosity and fluidity. Delivering nutrients and electrolytes to the body’s cells. Transporting dissolved gases, blood cells and plasma proteins. Moving metabolic waste products from the body’s cells to the kidneys, liver and lungs for excretion. Maintaining blood and cell osmotic pressure. Distributing thermal energy throughout the body.

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81
Q

Approximately 45% of blood volume is made up of _____ _____.

A

blood cells

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82
Q

Stem cells:

A

Bone marrow has stem cells that develop into blood cells and platelets.

83
Q

Red blood cells are called ____________.

A

erythrocytes

84
Q

Why are red blood cells red?

A

The red colour is due to iron in hemoglobin.

85
Q

What does hemoglobin do in red blood cells?

A

Hemoglobin transports oxygen and carbon dioxide.

86
Q

Describe the shape of red blood cells:

A

The cells are about 7 μm in diameter, and the biconcave shape increases surface area to maximize gas exchange.

87
Q

How are red blood cells produced in humans?

A

In humans, red blood cells are produced by nucleated stem cells in the bone marrow.

88
Q

Red blood cells lose their nucleus at maturity, so they are said to be __________.

A

enucleated

89
Q

The lack of a nucleus and mitochondria in red blood cells allows for…

A

more room for hemoglobin molecules.

90
Q

After about ___ days, red blood cells die and are broken down in the _____ and ______.

A

120, liver, spleen

91
Q

White blood cells are called __________.

A

leucocytes

92
Q

“leuco-” means “____”, “-cyte” means “____”

A

white, cell

93
Q

White blood cells are part of the immune system and are found in _____ and _____.

A

blood, lymph

94
Q

Describe white blood cells:

A

White blood cells are larger than red blood cells, nucleated, and comprise approximately 1% of blood volume.

95
Q

What do white blood cells target?

A

White blood cells target pathogens, such as viruses, bacteria and foreign cells.

96
Q

Platelets are also called _____________.

A

thrombocytes

97
Q

Describe platelets:

A

Platelets are enucleated, 2-4 μm in diameter, and produced by nucleated cells in the bone marrow called megakaryocytes.

98
Q

Platelets are involved in…

A

blood clotting.

99
Q

A blood clot prevents…

A

excess blood loss when a blood vessel is injured or torn.

100
Q

The steps involved in the blood clotting process are:

A

When a blood vessel is torn, platelets are attracted to the site of the wound. Platelets stick to the jagged edge of the wound, pile up and begin to plug the tear. The platelets release thromboplastin. Thromboplastin and calcium ions in the plasma convert prothrombin (a soluble plasma protein) into thrombin (an insoluble plasma protein). Thrombin converts fibrinogen into fibrin threads. The fibrin threads trap red blood cells and platelets to form a clot and prevent excess bleeding at the wound site.

101
Q

The lymphatic circulatory system:

A

A network of vessels and glands that extend throughout the body.

102
Q

The lymphatic system is a part of both the ___________ and ______ systems.

A

circulatory, immune

103
Q

The main functions of the lymphatic system are:

A

Lipid absorption in the lacteals of the digestive system, protection against disease, and osmoregulation.

104
Q

Osmoregulation:

A

The regulation of water in the blood.

105
Q

Lymph capillaries:

A

Closed-end tubes that lie next to the capillaries of the cardiovascular circulatory system.

106
Q

As blood circulates through the capillaries of the cardiovascular circulatory system, some of the plasma leaks out into the ____________ _____.

A

interstitial fluid

107
Q

The fluid that is absorbed by the lymphatic vessels is called _____.

A

lymph

108
Q

How does the lymphatic system carry lymph back to the cardiovascular circulatory system?

A

The lymphatic vessels carry lymph back to the cardiovascular circulatory system through large ducts that empty into veins
near the heart.

109
Q

How is lymph pushed through lymphatic vessels?

A

Pressure is low in lymph vessels, so skeletal muscles and one-way valves are used in the transport of lymph, (similar to the transport process in veins).

110
Q

Bone marrow:

A

A spongy material found in the centre of large bones, such as the femur, ribs and pelvic bones.

111
Q

What is produced in bone marrow?

A

Erythrocytes and leukocytes are produced in the bone marrow.

112
Q

Lymph nodes:

A

The lymph nodes are glands that are found throughout the lymphatic system.

113
Q

How do lymph nodes fight off infection? How are lymph nodes involved in maturation?

A

The lymph nodes contain leucocytes to fight off infection and are also the site of maturation for some leucocytes.

114
Q

Why do lymph nodes swell?

A

When a person is fighting off an infection, the number of leucocytes in the lymph nodes increase, causing the lymph nodes to swell.

115
Q

Pathogens:

A

Pathogens are organisms that cause disease.

116
Q

Give three examples of pathogens:

A

Examples include bacteria, viruses and fungi.

117
Q

The immune system:

A

Consists of all of the organs, tissues and processes that protect the human body from pathogens.

118
Q

The first line of defence:

A

Consists of all of the initial physical and chemical barriers that prevent the entry of pathogens into the body.

119
Q

Innate:

A

A person is born with it.

120
Q

Nonspecific:

A

It protects the body from pathogens in general and not particular pathogens.

121
Q

The ____ acts as both a physical and chemical barrier to infection.

A

skin

122
Q

This is the largest physical barrier in the body.

A

The skin

123
Q

This acts as a chemical barrier because it produces enzymes, called lysozymes, that kill microbes.

A

The skin

124
Q

Why can’t microorganisms live on the skin?

A

Perspiration is slightly acidic, making the skin inhospitable for microorganisms.

125
Q

What does saliva contain that helps deter microorganisms?

A

Saliva contains lysozymes and other antimicrobial agents.

126
Q

How do mucus and cilia get rid of pathogens physically?

A

Mucus physically traps pathogens that enter the respiratory tract and the beating of the cilia propels the pathogen-containing mucus up and out of the respiratory tract.

127
Q

How do mucus and cilia get rid of pathogens chemically?

A

Mucus acts as a chemical barrier because it contains lysozymes that chemically destroy microbes.

128
Q

How do tears get rid of pathogens physically?

A

Tears act as a physical barrier by flushing foreign substances out of the eyes.

129
Q

How do tears get rid of pathogens chemically?

A

Tears act as a chemical barrier because they contain lysozymes that destroy microbes.

130
Q

How does stomach acid get rid of pathogens chemically?

A

The low pH destroys many of the pathogens that are ingested with food.

131
Q

Fever:

A

Fever is an increase in body temperature triggered by infection.

132
Q

How does a fever deter pathogens?

A

The increased temperature makes it difficult for pathogens to survive and help to speed up the immune response.

133
Q

What is included in the first line of defence?

A

The skin, tears, stomach acid, mucus and cilia.

134
Q

What is included in the second line of defence?

A

Fever, inflammation, macrophages and natural killer cells.

135
Q

Inflammation:

A

Inflammation is the swelling and redness triggered by damage to body tissues.

136
Q

How is inflammation caused?

A

Inflammation is caused by vasodilation that occurs near the site of injury or infection and hormones that increase the permeability of capillaries.

137
Q

How does inflammation help the immune system?

A

The increased blood flow allows more immune system cells to travel to the site.

138
Q

Macrophages:

A

Macrophages are leucocytes that recognize and destroy pathogens through phagocytosis.

139
Q

Phagocytosis:

A

Phagocytosis is the process by which macrophages engulf pathogens and destroy them using enzymes.

140
Q

Antigen-presenting:

A

Macrophages take cell membrane marker molecules, called antigens, from the pathogen and push them to the surface of the
macrophage in a process called antigen-presenting.

141
Q

Natural killer cells belong to a class of leucocytes called ___________.

A

lymphocytes

142
Q

Natural killer cells:

A

Natural killer cells detect and destroy human cells that have become cancerous or have been infected by a virus.

143
Q

How is the third line of defence activated?

A

When pathogens bypass or overwhelm the innate immune responses.

144
Q

Lymphocytes:

A

The primary leucocytes involved in the third line of defence.

145
Q

What do lymphocytes do?

A

They are produced for specific pathogens in response to infection by a particular pathogen.

146
Q

T lymphocytes:

A

T lymphocytes, or T cells, are leucocytes that mature in the thymus gland.

147
Q

Helper T cells:

A

Helper T cells bind to and recognize foreign antigens presented by macrophages and release chemical signals that stimulate other T cells and B cells to mount an immune response to that specific pathogen.

148
Q

Killer T cells/cytotoxic T cells:

A

Killer T cells, or cytotoxic T cells, destroy pathogens and human cells
infected by viruses by puncturing the cell membrane.

149
Q

Suppressor T cells:

A

Suppressor T cells communicate with helper T cells and slow and suppress the immune response to ensure that healthy tissues are not destroyed.

150
Q

Memory T cells:

A

Memory T cells remain in the bloodstream after infection and are able to respond quickly if that particular pathogen is encountered again.

151
Q

B lymphocytes/B cells:

A

B lymphocytes, or B cells, are leucocytes that mature in the bone marrow.

152
Q

What do B cells do after being activated by helper T cells?

A

Once activated by helper T cells, B cells divide to produce plasma cells and memory B cells.

153
Q

Plasma cells:

A

Plasma cells produce large quantities of antibodies that attach to specific antigens found on a pathogen.

154
Q

Antibodies:

A

Antibodies are Y-shaped proteins that bind to antigens and neutralize a pathogen, making it easier for a macrophage to engulf and destroy the pathogen.

155
Q

Memory B cells:

A

Remain in the bloodstream after infection and are able to quickly mobilize an immune response.

156
Q

How do immunizations work?

A

Immunizations work by stimulating an acquired immune response.

157
Q

Vaccine:

A

A vaccine contains either an inactive form of the pathogen or a synthetic compound that resembles the pathogen. The immune system goes through the acquired immune response so that when that particular pathogen is encountered, the immune response will be faster and stronger.

158
Q

The principal structures of the excretory system include the:

A

Kidneys, ureters, urinary bladder and urethra

159
Q

Kidneys:

A

Kidneys are located on either side of the spine toward the back and they are protected by muscle, fat and ribs. Each kidney is about the size of your fist. About 25% of cardiac output is sent to the kidneys at rest. Kidneys are responsible for maintaining homeostasis in the blood by filtering metabolic wastes and balancing water, pH and ions.

160
Q

Ureter:

A

Wastes from the blood leave the kidney through a tube called the ureter. Each ureter is approximately 30 cm long and connects each kidney to the urinary bladder.

161
Q

How do things move through the ureter?

A

Peristaltic contractions, gravity and fluid pressure help move urine down the ureter to the bladder.

162
Q

The urinary bladder:

A

The urinary bladder collects urine from both ureters. In adults, the bladder can hold up to about 600mL of urine. A sphincter separates the bladder from the urethra.

163
Q

Urethra:

A

The urethra is a tube of smooth muscle that transports urine from the bladder to the outside of the body. Voluntary control of the urethra is controlled by a second sphincter. In adults, the length of the urethra is about 20 cm in males and 4 cm in females, which can contribute to higher incidences of urinary tract infections (UTI) in females.

164
Q

Blood pumped through the aorta branches to the kidneys via the _____ ________.

A

renal arteries

165
Q

Blood exits the kidneys via the _____ _____, which join the inferior vena cava.

A

renal veins

166
Q

The kidney has three regions:

A

Cortex, medulla, and renal pelvis.

167
Q

Cortex:

A

Outer region.

168
Q

Medulla:

A

Middle region.

169
Q

Renal Pelvis:

A

The hollow region where the kidney is connected to the ureter.

170
Q

Describe how the direction of blood flow differs in the renal arteries and the renal veins:

A

While renal arteries deliver blood from the aorta to the kidney to be filtered, renal veins do the opposite by taking filtered blood from the kidneys to the inferior vena cava.

171
Q

Where in the kidneys are the nephrons located?

A

Nephrons are located within the renal pyramids of the kidneys.

172
Q

Nephrons filter what?

A

Filter the plasma of blood, remove toxins, and regulate water and ions in the blood.

173
Q

What are three waste products found in urine?

A

Water, ions and toxins.

174
Q

What is a kidney stone?

A

Crystallized calcium oxalate passing from the kidney through the ureter to the bladder.

175
Q

The nephron is the functional unit of the _______.

A

kidneys

176
Q

Functions of the nephron:

A

Filtering the blood to remove wastes, forming urine and maintaining appropriate blood plasma compositions.

177
Q

As much as __% of the body’s blood is filtered by the kidneys at any time.

A

25

178
Q

What blood vessels are involved with the nephron?

A

Blood vessels associated with the nephron include the afferent arteriole, the efferent arteriole and the peritubular capillaries.

179
Q

Blood flows from the renal artery into ________ __________, that branch into a capillary bed called a __________.

A

afferent arterioles, glomerulus

180
Q

Blood flows from the glomerulus through the ________ _________ to the ___________ ___________ that surround the tubular parts of the nephron.

A

efferent arteriole, peritubular capillaries

181
Q

How does blood move through the kidneys?

A

Diffusion.

182
Q

Blood leaves the nephron through a venule that connects to the _____ ____.

A

renal vein

183
Q

Fluid from the blood enters the Bowman’s capsule which narrows into the ________ ______.

A

proximal tubule

184
Q

Fluid moves from the proximal tubule into descending and ascending sections of the ____ __ _____ and into the ______ ______.

A

loop of Henle, distal tubule

185
Q

Distal tubules from many nephrons connect to the __________ _____ which lead to the renal pelvis and exit the kidney via the ureter.

A

collecting ducts

186
Q

What things don’t pass through the Bowman’s capsule?

A

Blood cells, platelets and large proteins do not pass through the Bowman’s capsule into the urine.

187
Q

What happens in the proximal tubule?

A

Almost all nutrients, such as glucose and amino acids, are reabsorbed into the peritubular capillaries using active and passive transport. Most of the sodium ions are reabsorbed by active transport into the peritubular capillaries. Chloride and bicarbonate ions follow due to charge attraction. Water moves out of the proximal tubule by osmosis.

188
Q

The descending branch of the loop of Henle:

A

The descending branch of the loop of Henle is permeable to water, not solutes. Water leaves the filtrate to the area of higher solute concentration in the capillaries. The filtrate becomes concentrated with salts.

189
Q

The ascending branch of the loop of Henle:

A

The ascending branch of the loop of Henle is permeable to solutes, not water. Salts diffuse out of the filtrate into the capillaries.

190
Q

Hypertonic:

A

Excess solute.

191
Q

Reabsorption in the distal tubule:

A

Salts and bicarbonate can be actively transported out of the filtrate into the capillaries. Water follows by osmosis.

192
Q

Reabsorption in the collecting duct:

A

Salts can be actively transported out of the filtrate. Water and urea can diffuse out of the collecting duct.

193
Q

How is reabsorption limited?

A

Reabsorption of each substance is limited by a threshold level.

194
Q

Secretion:

A

The active transport of wastes from the peritubular capillaries to the filtrate in the proximal and distal tubules.

195
Q

Wastes secreted from the blood into the filtrate include:

A

Toxins, urea, ammonia, drugs, and potassium ions.

196
Q

The pH of blood plasma is regulated by a balance of ________ ___ secretion and ___________ ___ reabsorption.

A

hydrogen ion, bicarbonate ion

197
Q

Two hormones that cause increased water reabsorption from the nephron into the blood are:

A

Antidiuretic hormone (ADH) and aldosterone.

198
Q

When ADH or aldosterone is present…

A

Urine volume decreases and urine concentration increases.

199
Q

What hormone is released when dehydration occurs?

A

Antidiuretic hormone (ADH).

200
Q

What is ADH released by?

A

ADH is released by the pituitary gland.

201
Q

How does ADH increase plasma water levels and blood pressure?

A

ADH works to increase plasma water levels and blood pressure by increasing water permeability in the distal tubule and collecting duct. More water is able to be reabsorbed into the blood in the capillaries.

202
Q

When is aldosterone released?

A

Aldosterone is released when blood pressure is low.

203
Q

Where is aldosterone released?

A

Aldosterone is released by the adrenal glands located on top of the kidney.

204
Q

What does aldosterone do?

A

Aldosterone increases sodium ion reabsorption in the nephron, which increases water reabsorption.

Biology 20 (5 decks)

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