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MCAT Biology > Chapter 7: The Cardiovascular System > Flashcards

Chapter 7: The Cardiovascular System Flashcards

1
Q

After blood travels through veins, it is returned to the right side of the heart where it is pumped to the lungs to be ________________.

A

reoxygenated

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2
Q

________________ blood returns to the left side of the heart where it is once again pumped to the rest of the body.

A

oxygenated

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3
Q

What are the two pumps of the circulatory system?

A

Pulmonary circulation and systemic circulation

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4
Q

The right side of the heart accepts ____________ blood returning from the body and moves it to the lungs by way of the pulmonary ____________. This constitutes the first pump, which is ________________ circulation.

A

deoxygenated; arteries; pulmonary

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5
Q

The second pump is the left side of the heart, which receives ________________ blood from the lungs by way of the pulmonary ________ and forces it out to the body through the ________. This is ____________ circulation.

A

oxygenated; veins; aorta; systemic

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6
Q

The ________ are thin-walled structures where blood is received from either the ________ ____________ (deoxygenated blood entering the right side of the heart) OR the ________________ ________ (oxygenated blood enterting the left side of the heart).

A

atria; venae cavae; pulmonary veins

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7
Q

What is the valve between the right atrium and ventricle?

A

tricuspid valve

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8
Q

What is the valve between the left atrium and ventricle called?

A

bicuspid (mitral)

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9
Q

The valve that separates the right ventricle from pulmonary circulation is known as the ____________ valve.

A

pulmonary

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10
Q

The valve that separates the left ventricle from the aorta is the ____________ valve.

A

aortic

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11
Q

How many leaflets do the semilunar valves have?

A

three

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12
Q

Which side of the heart is more muscular?

A

the left side b/c the blood must be pumped to the body

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13
Q

What is the pathway of electrical conduction in the heart, in order?

A
  1. Sinoatrial (SA) node
  2. Atrioventricular (AV) node
  3. Bundle of His (AV bundle)
  4. Purkinje fibers
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14
Q

Where does impulse initiation begin?

A

SA node; no neurological input required

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15
Q

As the depolarization wave spreads from the SA node, it causes what to happen to the 2 atria?

A

They contract simultaneously

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16
Q

Atrial ____________ (contraction) results in an increase in atrial pressure that forces a little more blood into the ventricles.

A

systole

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17
Q

The additional volume of blood caused by atrial systole is called the ________ ________ and accounts for 5-30% of cardiac output.

A

atrial kick

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18
Q

After the SA node, the signal reaches the ____ ________, which sits at the junction of the atria and ventricles. The signal is delayed here. Why?

A

AV node; allows the ventricles to fill completely before they contract

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19
Q

After the AV node, the signal travels down the ____________ of ________ and its branches, which are embedded in the ________________ ________.

A

bundle of His; interventricular septum

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20
Q

After the bundle of His, the electrical signal travels to the ____________ ____________, which distribute the electrical signal through the ventricular muscle.

A

Purkinje fibers

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21
Q

The muscle cells are connected by ________________ ________, which contain many gap junctions directly connecting the cytoplasm of adjacent cells. This allows for coordinated ventricular contraction.

A

intercalated discs

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22
Q

The circulatory system is under ____________ control.

A

autonomic

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23
Q

____________ signals speed up the HR and increase contractility, ________________ signals, provided by the ________ nerve, slow down the HR.

A

sympathetic; parasympathetic; vagus

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24
Q

Each heartbeat is composed of 2 phases. What are they?

A

Systole and diastole

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25
Q

During ________, ventricular contraction and closure of the ____ valves occurs. Blood is pumped out of the ventricles.

A

systole; AV

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26
Q

During ____________, the ventricles are relaxed, the ____________ valves are closed, and blood from the atria fills the ventricles.

A

diastole; semilunar

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27
Q

________ ________ is the total blood volume pumped by a ventricle in a minute.

A

cardiac output

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28
Q

How do you calculate cardiac output (CO)?

A

CO = heart rate (HR, bpm) x stroke volume (SV, blood volume pumped per beat)

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29
Q

Blood travels away from the heart in ____________.

A

arteries

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30
Q

What is the largest artery?

A

aorta

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31
Q

Arteries ultimately branch into ____________, which lead to ____________ that perfuse the tissues.

A

arterioles; capillaries

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32
Q

On the venous side of the capillary network, capillaries join together into ____________, which join to form ________.

A

venules; veins

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33
Q

Venous blood empties into the superior and inferior ________ ________ for entry into which side of the heart?

A

vena cavae; right

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34
Q

All blood vessels are lined with ________________ cells, which release chemicals that aid in vasodilation and vasoconstriction and also aid in blood clot formation.

A

endothelial

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35
Q

Most arteries contain ________________ blood.

A

oxygenated

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36
Q

Which arteries contain deoxygenated blood?

A

pulmonary and umbilical arteries

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37
Q

________ are thin-walled, inelastic veins that transport blood to the heart.

A

Veins

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38
Q

All veins carry ____________ blood, with the exception of which veins?

A

deoxygenated; pulmonary and umbilical

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39
Q

________ are smaller venous structures that connect capillaries to the larger veins of the body.

A

venulues

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40
Q

Which has more smooth muscle - arteries or veins?

A

arteries

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41
Q

What gives veins less recoil than arteries?

A

the smaller amount of smooth muscle

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42
Q

Which can stretch more to accommodate larger quantities - arteries and veins?

A

veins

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43
Q

How do veins prevent backflow?

A

They have valves that will slam shut if blood tries to move backward

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44
Q

What happens if valves fail?

A

varicose veins

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45
Q

Most veins are surrounded by ____________ muscles, which squeeze the veins as the muscles contract.

A

skeletal

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46
Q

How does blood circulate?

A
  1. Deoxygenated blood arrives at heart from superior (from above) and inferior (from below) venae cavae at the right atrium
  2. From the right atrium, it goes through the tricuspid valve into the right ventricle
  3. From the right ventricle, it goes through the pulmonary valve to the pulmonary arteries, to the lungs
  4. Gas exchange
  5. The pulmonary veins carry oxygenated blood to the left atrium, which travels through the bicuspid (mitral) valve to the left ventricle
  6. From the left ventricle, blood flows through the aortic valve, to the aorta, to the rest of the body
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47
Q

In most cases, blood will pass through (how many?) capillary bed(s) before returning to the heart.

A

one

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48
Q

There are, however, 3 ________ ____________ in the body, in which blood will pass through 2 capillary beds inseries before returning to the heart.

A

portal systems

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49
Q

In the ________ portal system, blood leaving capillary beds in the walls of the gut passes through the hepatic portal vein before reaching the capillary beds in the liver.

A

hepatic

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50
Q

In the ________________ portal system, blood leaving capillary beds in the hypothalamus travels to a capillary bed in the ____________ ____________ to allow for paracrine secretion of releasing hormones.

A

hypohyseal; anterior pituitary

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51
Q

In the ________ ____________ system, blood leaving the glomerulus travels through an efferent arteriole before surrounding the nephron in a capillary network called the ________ ________.

A

renal portal; vasa recta

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52
Q

________ is the liquid portion of blood, an aqueous mixture of nutrients, salts, respiratory gases, hormones, and blood proteins.

A

Plasma

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53
Q

Plasma can be further refined via the removal of ____________ ____________ into ________.

A

clotting factors; serum

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54
Q

What are the 3 cellular categories that comprise the cellular portion of blood?

A
  1. erythrocytes
  2. leukocytes
  3. platelets
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55
Q

All blood cells are formed from ________________ stem cells, which originate from where?

A

hematopoietic; bone marrow

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56
Q

The ____________, or red blood cell, is a specialized cell designated for oxygen transport.

A

erythrocyte

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57
Q

Why doesn’t oxygen not dissolved in the cytoplasm of the red blood cell?

A

Molecular oxygen is nonpolar and has low solubility in aqueous environments

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58
Q

Each erythrocyte contains about 250 million molecules of ____________, each of which can bind how many molecules of oxygen?

A

hemoglobin; 4

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59
Q

Do red blood cells have organelles, nuclei, or mitochondria?

A

No

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60
Q

How do red blood cells get ATP without mitochondria?

A

Since there are no mitochondria, they cannot undergo oxidative phosphorylation, so they rely on glycolysis for ATP, with lactic acid as the main byproduct

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61
Q

Can red blood cells divide? Why?

A

No, because they lack nuclei

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62
Q

____________ usually comprise less than 1% of total blood volume.

A

leukocytes

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63
Q

What are the 2 classes of leukocytes?

A
  1. granulocytes
  2. agranulocytes
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64
Q

How many types of leukocytes are there?

A

5

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65
Q

What are the 3 types of granulocytes?

A
  1. neutrophils
  2. eosinophils
  3. basophils

They all end in -phil!

66
Q

Why are granular leukocytes called that?

A

Because they contain cytoplasmic granules that are visible by microscopy

67
Q

What characterizes granulocytes?

A
  • Have compounds that are toxic to invading microbes that can be released through exocytosis
  • Involved in inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites
68
Q

What are the 2 agranulocytes?

A
  1. lymphocytes
  2. monocytes
69
Q

What characterizes agranulocytes?

A
  • They do not have granules that are released by exocytosis.
  • They are important in the specific immune response (targeted)
70
Q

How do many vaccines work?

A

They target agranulocytes and expose them to a weakened pathogen to create memory cells

71
Q

Where does lymphocyte maturation take place?

A

Either bone marrow or thymus

72
Q

What lymphocytes are produced in the bone marrow? What are they responsible for?

A

B-cells; antibody generation

73
Q

What lymphocytes are produced in the thymus? What are they responsible for?

A

T-cells; kill virally infected cells and activate other immune cells

74
Q

What do monocytes do?

A

Phagocytize foreign matter, like bacteria

75
Q

Once monocytes leave the bloodstream and enter an organ, monocytes are renamed ____________. They can have specific names depending on which organ they are in.

A

macrophages

76
Q

Macrophages in the CNS are called ____________; in the skin, they are called ________________ cells; in bone, they are called ____________.

A

microglia, Langerhans cells, osteoclasts

77
Q

________________ or ________ are cell fragments or shards released from cells in bone marrow known as ________________.

A

thrombocytes, platelets, megakaryotcytes

78
Q

What do platelets do?

A

Assist in blood clotting and are present in high concentrations

79
Q

The production of blood/platelets is called ____________, and is triggered by a number of hormones, growth factors, and cytokines.

A

hematopoiesis

80
Q

________________ is secreted by the kidney and stimulates RBC development. ____________ is secreted by the liver and kidney and stimulates mainly platelet development.

A

erythropoietin, thrombopoietin

81
Q

Red blood cells express surface proteins called ____________. It is any specific target (usually a protein) to which the immune system can react.

A

antigens

82
Q

What are the two major antigen families relevant for blood groups?

A
  1. ABO antigens
  2. Rh factor
83
Q

What does codominance mean?

A

A person can express one, both, or none of the ABO antigens

84
Q

Which alleles are codominant in the ABO system?

A

A and B

85
Q

Which allele is recessive to both the A and B alleles?

A

O

86
Q

What are the symbols for each allele of ABO?

A

IA and IB are codominant; i (O) is recessive

87
Q

People with type ____ blood are universal donors because their blood will not cause ABO-related hemolysis in any recipient.

A

O

88
Q

A recipient who is type O will produce both anti-A and anti-B antibodies, so what kind of blood can they receive?

A

Type O only

89
Q

People with type ____ blood are considered universal recipients because they can receive blood from all types: no blood antigen is foreign to these individuals.

A

AB

90
Q

Whole blood is almost never given in a trasnfusion; what is given instead?

A

packed RBCs, with no plasma

91
Q

Antibodies are created in response to ____________, and they specifically target that.

A

antigens

92
Q

An individual who is Rh-negative would not have any ____-____ antibodies prior to exposure to blood that contains it.

A

anti-Rh

93
Q

The ____ factor is also a surface protein expressed on RBCs.

A

Rh

94
Q

Rh+ and Rh- refers to the presence or absence of a specific allele called ____.

A

D

95
Q

If a person who is pregnant is Rh- and the fetus is Rh+, what happens?

A

They person becomes sensitized to the Rh factor and the person’s immune system will begin making antibodies against it

96
Q

For subsequent pregnancies in which the fetus is Rh+, what will happen if the mom has anti-Rh antibodies? What is this called?

A

The anti-Rh antibodies can cross the placenta and attack the fetal blood cells, resulting in hemolysis of the fetal cells.

Erythro-blastosis fetalis

97
Q

there is les concern with maternal-fetal ABO mismatching because antibodies against AB antigens are of a class called ____, which does not readily cross the placenta (unlike anti-Rh IgG antibodies).

A

IgM

98
Q

Blood pressure is a measure of what? What can be used to measure it?

A

force per unit area exerted on the wall of the blood vessels; sphygmomanometer

99
Q

Blood pressure is expressed as a ratio of what?

A

Systolic (ventricular contraction) to diastolic (ventricular relaxation) pressures

100
Q

Pressure gradually (drops/raises?) from the arterial to venous circulation. Where does the largest drop occur?

A

drops; cross the arterioles

101
Q

Just like an electromotive force (voltage) drives a current through a given electrical resistance, the ____________ ____________ across the circulatory system drives ____________ ____________ through a given ____________ ________________.

A

pressure gradient; cardiac output; vascular resistance

102
Q

Ohm’s law (V = IR) can be translated into an equation for circulation. What is it?

A

ΔP = CO x TPR

P = pressure differential
CO = cardiac output
TPR = peripheral resistance

103
Q

Arterioles and capillaries act like ____________ in a circuit.

A

resistors

104
Q

Resistance is based on what 3 factors?

A
  1. Resistivity
  2. Length
  3. Cross-sectional area
105
Q

Relationship between blood vessel length and resistance?

A

Longer = more resistance

106
Q

Relationship between cross-sectional area of blood vessel and resistance?

A

Larger = less resistance

107
Q

With the exception of 3 portal systems, all systemic capillary beds are in ____________ with each other. Thus, opening them up will (increase/decrease?) vascular resistance and, if the body can compensate, increase ________ ________.

A

parallel; decrease; cardiac ouput.

108
Q

Blood pressure is regulated using ____________ in the walls of the vasculature.

A

baroreceptors

109
Q

What do baroreceptors detect?

A

Changes in the mechanical forces on the wall of the vessel

110
Q

When the blood pressure is too low, they can stimulate the ____________ nervous system, which causes ________________, which increase blood pressure.

A

sympathetic; vasoconstriction

111
Q

Chemoreceptors can sense when the ____________ of the blood is too high, which could indicate dehydration.

A

osmolarity

112
Q

Dehydration prompts the release of ____________ hormone, a peptide hormone made in the ____________ but stored in the posterior pituitary, which increases the reabsorption of water, which increases blood volume and pressure.

A

antidiuretic; hypothlamus

113
Q

If blood pressure is too high, specialized atrial cells are able to secrete what hormone?

A

atrial natriuretic peptide

114
Q

What does atrial natriuretic peptide (ANP) do?

A

It aids in the loss of salt within the nephron, which acts as a natural diuretic with loss of fluid.

115
Q

Oxygen is carried by ____________.

A

hemoglobin

116
Q

How many subunits does hemoglobin have?

A

4

117
Q

Where does oxygen bind in the heme group?

A

At the central iron atom

118
Q

The binding of releasing of O2 from the iron atom is what type of reaction?

A

redox

119
Q

Blood oxygen levels is measured as the ________ ____________ of O2. It requires arterial blood sampling.

A

partial pressure

120
Q

________ ____________ is the % of hemoglobin molecules carrying oxygen and can be measured with a finger probe.

A

oxygen saturation

121
Q

In the lungs, oxygen diffuses into the ____________ capillaries.

A

alveolar

122
Q

As the first oxygen binds to a heme group, it induces a conformational shift in hemoglobin from what to what?

A

Taut to relaxed

123
Q

After the first oxygen binds, the conformational shift (increases/decreases?) hemoglobin’s affinity for oxygen.

A

increases

124
Q

Once all subunits are bound, the removal of one molecule of oxygen induces another conformational shift that (increases/decreases) the overall affinity for O2.

A

decreases

125
Q

Carbon dioxide gas, like O2, is ____________ and thus has low solubility in the aqueous plasma.

A

nonpolar

126
Q

The vast majority of CO2 exists in the blood as the ____________ ion.

A

HCO3-

127
Q

WHen CO2 enters an RBC, it encounters the enzyme ____________ ____________, which catalyzes the combination reaction between CO2 and H2O to form ____________ ________.

A

carbonic anhydrase; carbonic acid (H2CO3)

128
Q

Carbonic acid, a weak acid, will dissociate into what 2 things?

A

proton + bicarbonate anion

129
Q

The hydrogen ion (proton) and bicarbonate ion both have (low/high) solubilities in water. This is why they are an effective way of transporting metabolic waste products to the lungs for excretion.

A

high

130
Q

What is the CO2 reaction?

A
131
Q

____ can have allosteric effects on the oxyhemoglobin dissociation curve.

A

pH

132
Q

If CO2 increases, the equation shifts right, causing increased H+. These protons can bind to hemoglobin, which does what? What is this called?

A

Reduces hemoglobin’s affinity for oxygen; the Bohr effect

133
Q

Exercise causes a ________ shift of the oxyhemoglobin curve. What happens to PaCO2 during exercise? [H+]? Temp?

A

right; increases, increases, increases

134
Q

________ ____________ has a higher affinity for oxygen than adult hemoglobin (HbA). Why?

A

fetal hemoglobin; fetal RBCs must literally pull O2 off of maternal hemoglobin and onto fetal hemoglobin

135
Q

If someone hyperventilates, excess CO2 is blown off, which shifts the bicarbonate buffer system ________ and decreases the concentration of protons. This leads to an increase in pH. This is known as respiratory ____________.

A

left; alkolosis

136
Q

How does the kidneys compensate for respiratory alkalosis?

A

Increases excretion of bicarbonate

137
Q

Carbs and amino acids are absorbed into capillaries of the ________ ____________ and enter the systemic circulation via what portal system?

A

systemic circulation; hepatic

138
Q

Fats are absorbed into ________ in the small intestine, bypassing the hepatic portal circulation to enter systemic circulation via the ____________ duct.

A

lacteal; thoracic

139
Q

Wastes enter the bloodstream by traveling down (what?) from the tissues to the capillaries.

A

concentration gradients

140
Q

Hormones enter the circulation where? How does this occur?

A

Enter the circulation via exocytosis

141
Q

____________ pressure is the force per unit area that the blood exerts against the vessel walls.

A

Hydrostatic

142
Q

What generates hydrostatic pressure?

A

Contraction of the heart and the elasticity of the arteries

143
Q

Where is hydrostatic pressure measured?

A

upstream in the large arteries as blood pressure

144
Q

What does hydrostatic pressure do?

A

Pushes fluid out of the bloodstream and into the interstitium through the capillary walls

145
Q

________ pressure is the “sucking” pressure generated by solutes as they attempt to draw water into the bloodstream. Because most of this is attributable to plasma proteins, itis called ____________ pressure.

A

osmotic; oncotic

146
Q

At the arteriole end of a capillary bed, which type of pressure is larger than the other? What does this cause?

A

hydrostatic pressures > oncotic pressure

net efflux of water from circulation - causes hydrostatic pressure to drop, but osmotic pressure stays the same

147
Q

At the venule end of a capillary bed, ________ pressure (pushing fluid out) is below ________ pressure (drawing fluid in), and there is a net influx of water back into the circulation.

A

hydrostatic; oncotic

148
Q

The balance of hydrostatic and osmotic pressures are called ____________ ________ is essential for maintaining the proper fluid volumes and solute concentrations inside and outside the vasculature.

A

Starling forces

149
Q

Accumulation of excess fluid in the interstitium results in a condition called ________.

A

edema

150
Q

Some interstitial fluid is also taken up by the lymphatic system. Most lymphatic fluid (________) is returned to the central circulatory system by way of a channel called the ________ ________.

A

lymph; thoracic duct

151
Q

Again, ____________ protect the vascular system in the event of damage by forming a clot.

A

platelets

152
Q

Clots are composed of what 2 things? What do they prevent?

A

Coagulation factors (proteins) and platelets; prevent/minimize blood loss

153
Q

When the endothelium of a blood vessel is damaged, it exposes the underlying connective tissue, which contains ________ and a protein called ________ ________.

A

collagen, tissue factor

154
Q

When platelets come into contact with exposed collagen, they sense this as evidence of injury. What do they do in response?

A

They release their contents and begin to aggregate

155
Q

While platelets aggregate, what else occurs?

A

Coagulation factors (typically secreted by liver) sense tissue factor and initiate a complex activation cascade.

156
Q

The endpoint of the cascade is the activation of ____________ to form ________ by ____________.

A

prothrombin, thrombin, thromboplastin

157
Q

Thrombin converts ________ into ________

A

fibrinogen to fibrin

158
Q

What does fibrin do?

A

Forms small fibers that aggregate and cross-link into a woven structure that captures RBCs and other platelets to form a stable clot over the area of damage.

159
Q

____________ formation, or blood clotting, occurs when blood vessels are injured.

A

Thrombus

160
Q

What begins the process of blood clotting?

A

Platelets attach to the matrix that becomes exposed when the endothelial cells lining blood vessels are disrupted.

161
Q

After platelets attach, ____________ molecules are activated, causing them to adhere to circulating proteins like ____________, which form bridges to additional platelets.

A

integrin; fibrinogen

162
Q

What breaks down clots? What is it generated from?

A

Plasmin; plasminogen

MCAT Biology (12 decks)

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