Chapter 7: The Cardiovascular System Flashcards
1
Q
How many chambers does the heart contain?
A
4
2
Q
Where does deoxygenated blood enter the heart? Where does oxygenated blood exit the heart?
A
- Deoxygenated enters at the right side of the heart
- Oxygenated exits at the left side
3
Q
How is deoxygenated blood moved to the lungs?
A
By way of the pulmonary arteries
4
Q
How is oxygenated blood moved to the heart?
A
By way of the pulmonary veins
5
Q
What are the two types of circulation?
A
- Pulmonary circulation
- Systemic circulation
6
Q
What are atria?
A
Thin-walled structures where blood is received
7
Q
The atria may receive blood from what? (2)
A
- Venae cavae (deoxygenated blood entering the right heart)
- Pulmonary veins (oxygenated blood entering the left heart)
8
Q
The atria contract to push blood into the __________.
A
ventricules
9
Q
What is the mnemonic for atrioventricular valves?
A
LAB: Left Atrium = Bicuspid (mitral)
RAT: Right Atrium = Tricuspid
10
Q
The atria are separated from the ventricles by what?
A
Atrioventricular valves
11
Q
The ventricles are separated from the vasculature by what?
A
Semilunar valves
12
Q
What does the pulmonary valve separate?
A
The right ventricle from pulmonary circulation
13
Q
What does the aortic valve separate?
A
The left ventricle from the aorta
14
Q
How many leaflets do the semilunar valves have?
A
Three
15
Q
Name the components of the electrical conduction system of the heart, in order.
A
- Sinoatrial node (SA node)
- Atrioventricular node (AV node)
- His (AV bundle) and its branches
- Purkinje fibers
16
Q
Where does impulse initiation occur for the electrical conduction system of the heart? How many signals per minute are generated without requiring any neural input?
A
- SA node
- 60-100 signals per minute
17
Q
Where is the SA node located?
A
Wall of the right atrium
18
Q
What percentage of cardiac output does the atrial kick account for?
A
5-30%
19
Q
Where is the AV node located?
A
At the junction of the atria and ventricles
20
Q
Where is the bundle of His?
A
Embedded in the interventricular septem
21
Q
The muscle cardiac cells are connected by what?
A
Intercalated discs
22
Q
The parasympathetic system slows down the heart rate, provided by the ______ nerve.
A
vagus
23
Q
What happens during systole?
A
Ventricular contraction and closure of the AV valves occurs and blood is pumped out of the ventricles
24
Q
What happens during diastole?
A
The heart is relaxed, the semilunar valves are closed, and blood from the atria fills the ventricles
25
Contraction, which increases blood pressure, is during _________, while ________ is responsible for relaxation.
systole
| diastole
26
What is the equation for cardiac output? What is the average cardiac output for humans?
- CO = HR x SV
- Heart Rate (beats per minute)
- Stroke Volume (Volume of blood pumped per beat)
- 5 liters per minute
27
When does the first sound (lub) appear?
When the two AV valves close at the start of systole to prevent backflow into the atria
28
When does the second sound (dub) appear?
When the two semilunar valves close at the end of systole to prevent backflow into the ventricles
29
What happens in terms of pressure and volume when the aortic valve opens?
- Pressure increases
| - Volume decreases
30
What happens in terms of pressure and volume when the aortic valve closes?
- Pressure decreases
| - Volume increases
31
Blood travels away from the heart in ________.
arteries
32
What is the largest artery?
Aorta
33
All blood vessels are lined with what kind of cells?
Endothelial cells
34
What are the functions of endothelial cells in the cardiovascular system? (3)
- Helps to maintain the vessel by releasing chemicals that aid in vasodilatation and vasoconstriction
- Allow white blood cells to pass through the vessel wall and into the tissues during an inflammatory response
- Release chemicals when damaged that are necessary in the formation of blood clots to repair the vessel and stop bleeding
35
How are arteries and veins similar in terms of structure? How are they different?
- They are composed of the same types of cells
| - Arteries have much more smooth muscle than veins
36
Most arteries contain (oxygenated/deoxygenated) blood. What are the exceptions?
- Oxygenated
| - Pulmonary arteries and umbilical arteries
37
Smaller, muscular arteries are known as what?
Arterioles
38
Why must the left side of the heart generate much higher pressures?
To overcome the resistance caused by systemic arteries
39
How thin are the walls of capillaries? How do red blood cells travel through capillaries?
- Single endothelial cell layer
| - Single-file line
40
What is the interface for communication of the circulatory system with the tissues?
Capillaries
41
What causes a bruise?
When capillaries are damaged, blood can leave the capillaries and enter the interstitial space
42
Veins are (elastic/inelastic).
inelastic
43
Veins carry (oxygenated/deoxygenated) blood. What are the exceptions?
- Deoxygenated
| - Pulmonary and umbilical veins
44
_________ are smaller venous structures that connect capillaries to the larger veins of the body
Venules
45
Are veins or arteries able to stretch to accommodate greater amounts of blood?
Veins
46
The pressure at the bottom of the _______ ______ _____ can be quite high, going as high as 200 mmHg or more.
inferior vena cava
47
What structures do veins possess to push blood forward and prevent backflow?
Valves
48
What are varicose veins? Who is susceptible?
- Veins that have valves that were unable to close
| - Pregnant women
49
What is the external force that veins rely on to generate the pressure to push blood toward the heart?
Skeletal muscles, which squeeze the veins as the muscles contract
50
Blood returns to the heart from the body via the _______ ________
venae cava
51
What is the pathway of blood circulation?
- Right atrium (tricuspid valve)
- Right ventricle (pulmonary valve)
- Pulmonary artery
- Lungs
- Pulmonary veins
- Left atrium (mitrall valve)
- Left ventricle (aortic valve)
- Aorta
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
- Venae cavae
- Right atrium
52
Which tree portal systems in the body have blood that pass through two capillary beds?
- Hepatic portal system
- Hypophyseal portal system
- Renal portal system
53
What are the two capillary beds of the hepatic portal system?
Blood leaving the capillary beds in the walls of the gut passes through the hepatic portal vein before reaching the capillary beds in the liver
54
What are the two capillary beds of the hypophyseal portal system?
Blood leaving capillary beds in the hypothalamus travels to a capillary bed in the anterior pituitary to allow for paracrine secretion of releasing hormones
55
What are the two capillary beds of the renal portal system?
Blood leaving the glomerulus travels through an efferent arteriole before surrounding the nephron in a capillary network called the vasa recta
56
Which valve prevents backflow in the right atrium?
Tricuspid valve
57
Which valve prevents backflow in the right ventricle?
Pulmonary valve
58
Which valve prevents backflow in the left atrium?
Mitral (bicuspid) valve
59
Which valve prevents backflow in the left ventricle?
Aortic valve
60
Do arteries, capillaries, or veins contain valves?
- Arteries: no
- Capillaries: no
- Veins: yes
61
Do arteries, capillaries, or veins contain much smooth muscle?
- Arteries: yes, a lot
- Capillaries: no
- Veins: yes, a little
62
Why does the right side of the heart contain less cardiac muscle than the left side?
The right side of the heart pumps blood into a lower-resistance circuit and must do so at lower pressures; therefore, it requires less muscle
63
What percentage of plasma to cells is blood composed of?
- 55% plasma
| - 45% cells
64
What is plasma?
The liquid portion of blood, which is an aqueous mixture of nutrients, salts, respiratory gases, hormones and blood proteins
65
What are the three major categories of the cellular component of blood?
- Erythrocytes
- Leukocytes
- Platelets
66
Blood cells are all formed from what type of cell? Where do they originate from?
From hematopoietic stem cells, which originate in the bone marrow
67
What is an erythrocyte?
Specialized cell designed for oxygen transport
68
How is oxygen bound to an erythrocyte?
- Each molecule of hemoglobin contained in a red blood cell can bind four molecules of oxygen
- Oxygen does not dissolve in the aqueous cytoplasm of the cell as it is nonpolar
69
What is the function of the biconcave structure of red blood cells?
- The shape assists them in traveling through tiny capillaries
- The shape increases the cell's surface area, which allows for greater gas exchange
70
What happens when red blood cells mature? Why?
- When they mature, the nuclei, mitochondria, and other membrane-bound organelles are lost
- Makes space for the molecules of hemoglobin
71
What kind of biochemical mechanisms do red blood cells carry-out for energy purposes?
Glycolysis with lactic acid (arising from fermentation) as the main by-product
72
Can red blood cells divide? Why or why not?
No, since they lack nuclei
73
How long can erythrocytes survive in the bloodstream? How are they degraded?
- 120 days
| - The cells in the liver and spleen phagocytize old red blood cells and recycle them for their parts
74
What is a hematocrit measure?
Measurement of how much of the blood sample consists of red blood cells, given as a percentage
75
What is a normal hemoglobin amount for males and females?
- Males: 13.5 and 17.5
| - Females: 12.0 and 16.0
76
What is a normal hematocrit amount for males and females?
- Males: 41 and 53%
| - Females: 36 and 46%
77
What percent of total blood volume do leukocytes comprise?
Less than one percent
78
What are the two classes of leukocytes?
- Granulocytes
| - Agranulocytes
79
Name the three granulocytes.
Neutrophils, eosinophils, and basophils
80
What are granulocytes?
Leukocytes that contain cytoplasmic granules that are visible by microscopy
81
What is the function of the granules in granulocytes? What are they involved in?
- The granules contain a variety of compounds that are toxic to invading microbes, and their contents can be released through exocytosis
- Involved in inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites
82
Name the two agranulocytes.
Lymphocytes and monocytes
83
What is the primary function of lymphocytes?
Involved in the specific immune response, the body's targeted fight against particular pathogens, such as viruses and bacteria
84
Many vaccines work by training ___________, which help our body learn from experience and are prepared to mount a fast response upon repeated exposure to familiar pathogens.
lymphocytes
85
Where do B-cells mature? What are they responsible for?
- Spleen or in lymph nodes
| - Responsible for antibody generation
86
Where do T-cells mature? What are they responsible for?
- Thymus
| - Kill virally infected cells and activate other immune cells
87
What is the primary function of monocytes?
Phagocytize foreign matter such as bacteria
88
Once they leave the bloodstream and enter an organ, monocytes are renamed __________.
macrophages
89
What is the macrophage population called in the central nervous system, skin, and bone?
- CNS: microglia
- Skin: Langerhans cells
- Bone: osteoclasts
90
What are thrombocytes (platelets)? What are they released from?
Cell fragments or shards released from cells in the bone marrow known as megakaryocytes
91
What is the primary function of platelets?
Assist in blood clotting
92
What is the production of blood cells and platelets called? What is it triggered by?
- Hematopoiesis
| - Hormones, growth factors, cytokines
93
What is the function of erythropoietin? What is it secreted by?
- Secreted by the kidney
| - Stimulates mainly RBC development
94
What is the function of thrombopoietin? What is it secreted by?
- Secreted by the liver and kidney
| - Stimulates mainly platelet development
95
What are the two major antigen families relevant for blood groups?
- ABO antigens
| - Rh factor
96
What are the four blood types?
- A
- B
- AB
- O
97
Which ABO antigens are dominant, and which is recessive?
- A and B are dominant
| - O is recessive
98
What are the antigens produced by O? What are the antibodies produced? What can it donate to? What can it receive from?
- Antigens: none
- Antibodies: anti-A and anti-B
- Can donate to A, B, AB, O (universal donor)
- Can receive from O only
99
What are the antigens produced by A? What are the antibodies produced? What can it donate to? What can it receive from?
- Antigens: A
- Antibodies: anti-B
- Can donate to A, AB
- Can receive from A, O
100
What are the antigens produced by B? What are the antibodies produced? What can it donate to? What can it receive from?
- Antigens: B
- Antibodies: anti-A
- Can donate to B, AB
- Can receive from B, O
101
What are the antigens produced by AB? What are the antibodies produced? What can it donate to? What can it receive from?
- Antigens: A and B
- Antibodies: none
- Can donate to AB only
- Can receive from A, B, AB, O (universal recipient)
102
What is the Rh factor?
The presence (+) or absence (-) of the specific allele D
103
Rh-positivity follows what kind of inheritance?
- Autosomal dominant inheritance
| - One positive allele is enough for the protein to be expressed
104
What is erythroblastosis fetalis?
- If a women is Rh- and her fetus is Rh+, she will begin making antibodies against it
- Any subsequent pregnancy in which the fetus is Rh+ will present a problem
- Maternal anti-Rh antibodies can cross the placenta and attack the fetal blood cells, resulting in hemolysis of the fetal cells
105
Which cell type(s) in blood do not contain nuclei?
Erythrocytes and platelets
106
What is the definition of blood pressure? What is it measured with? How is it expressed?
- A measure of the force per unit area exerted on the wall of the blood vessels
- Measured with a sphygmomanometer
- Expressed as a ratio of the systolic to diastolic pressures
107
When does blood pressure drop during circulation? When is the largest drop?
- Gradually drops from the arterial to venous circulation
| - The largest drop occurs across the arterioles
108
How can Ohm's law (V = IR) be translated into circulation?
- P = CO x TPR
- P is the pressure differential across the circulation
- CO is the cardiac output
- TPR is the total peripheral resistance
109
What is the effect of opening capillary beds that are all in parallel with each other?
Decreases vascular resistance (like adding another resistor in parallel) and, assuming the body can compensate, increase cardiac output
110
How is blood pressure regulated?
- Using baroreceptors in the walls of the vasculature
| - Baroreceptors detect changes in the mechanical forces on the walls of the vessel
111
What do baroreceptors signal when blood pressure is too low?
Stimulate the sympathetic nervous system, which causes vasoconstriction, increasing blood pressure
112
What happens when chemoreceptors sense that blood osmolarity is too high? What does it indicate?
- Possible dehydration
- Promotes the release of ADH, which is made in the hypothalamus and stored in the posterior pituitary, which increases the reabsorption of water and blood pressure
113
What is the function of atrial natriuretic peptide (ANP)?
Aids in the loss of salt within the nephron, acting as a natural diuretic with loss of fluid when blood pressure is too high
114
What is a normal partial pressure of O2 (PaO2)? Why is it inconvenient?
- 70 - 100 mgHg
| - Since it involves taking a sample of blood from an artery
115
What is oxygen saturation? How is it measured?
- Percentage of hemoglobin molecules carrying oxygen (around 97%)
- Easily measured using a finger probe
116
Explain the feedback-like (spiralling forward) mechanism of oxygen bound to hemoglobin. What is it called?
- As heme groups acquire an oxygen molecule, the affinity increases due to conformational changes
- With the removal of one molecule of O, the affinity of heme for oxygen decreases, making it easier for oxygen to leave the groups
- Cooperative binding
117
The cooperative binding curve of oxygen to hemoglobin looks like what?
Sigmoidal (S-shaped)
118
What is the partial pressure of O2 in the lungs, in the tissues at rest, and in tissues during exercise?
- Lungs: 100%
- Tissues during rest: 40%
- Tissues during exercise: 20%
119
The vast majority of CO2 exists in the blood as what? Why?
- HCO3- (bicarbonate ion)
| - As an ion, it has high solubility in water, making it an effective method of transport
120
What happens when CO2 enters a red blood cell?
It encounters carbonic anhydrase, which catalyzes the combination reaction between CO2 and water to form carbonic acid (H2CO3)
121
What does carbonic acid dissociate into?
A proton and the bicarbonate anion
122
What happens when HCO3- enters the alveolar capillaries?
Combines with a proton to form H2CO3, and is catalyzed by carbonic anhydrase to CO2 (and excreted)
123
What is the Bohr effect? How does it affect the oxyhemoglobin curve?
- Increased CO2 production causes a right shift in the bicarbonate buffer equation, resulting in increased H+
- H+ binds to hemoglobin, reducing its affinity for oxygen
- Causes a right shift in the oxyhemoglobin curve
- Results in greater unloading of oxygen into the tissues
124
What are the five factors that can cause a right shift in the oxyhemoglobin dissociation curve? What does that reflect?
- High partial pressure of CO2
- High H+
- Low pH
- High temperature
- High concentration of 2,3-biphosphoglycerate
- Indicates a decreased affinity for oxygen
125
How can the renal system compensate for hyperventilation (excess CO2 blown off)?
Increases the excretion of bicarbonate, which brings the pH back to normal
126
How can the bicarbonate buffer system compensate for renal tubular acidosis type I, in which the kidneys are unable to excrete acid effectively?
The excess CO2 formed in the process can be exhaled, and the person may increase respiratory rate to compensate, bringing the pH back to normal
127
How does fetal hemoglobin compare to adult hemoglobin? How does that affect the oxyhemoglobin dissociation curve?
- Fetal hemoglobin has a higher affinity for oxygen
| - Left-shifted curve compared to adult hemoglobin
128
Where are carbohydrates and amino acids absorbed into the bloodstream? How do they enter systemic circulation?
- Absorbed into the capillaries of the small intestine
| - Via the hepatic portal system
129
How are fats absorbed into the blood stream? How do they enter systemic circulation?
- Absorbed into lacteals in the small intestine
| - Bypassing the hepatic portal circulation to enter systemic circulation via the thoracic duct
130
What happens when peptide hormones reach their target tissue?
They activate cell-surface receptors
131
What happens when steroid hormones reach their target tissue?
They diffuse into the cell to activate intracellular or intranuclear receptors
132
What are the two essential pressure gradients to maintain a proper balance of fluid volume and solute concentrations between the blood and the interstitium?
- Hydrostatic pressure
| - Osmotic pressure
133
What is hydrostatic pressure?
- The force per unit area that the blood exerts against the vessel walls
- Pushes fluid out of vessels
- Dependent on blood pressure driven by the heart and the elastic arteries
134
What is osmotic pressure? What is it also called?
- Pulls fluid back into the vessels
- Dependent on the number of particles (usually proteins) dissolved in the plasma
- Oncotic pressure
135
At the arteriole end of a capillary bed, how does hydrostatic pressure compare to oncotic pressure?
- Hydrostatic > oncotic
| - Net efflux of water from the circulation
136
At the venule end of the capillary bed how does hydrostatic pressure compare to oncotic pressure?
- Hydrostatic < oncotic
| - Net influx of water back into the circulation
137
What are Starling forces?
Balance between the hydrostatic pressure and oncotic pressure, which is essential for maintaining proper fluid volumes and solute concentrations
138
Accumulation of excess fluid in the interstitium results in a condition called ______.
edema
139
How does lymphatic fluid returned to the central circulatory system?
By way of a channel called the thoracic duct
140
What are clots composed of? What do they prevent?
- Coagulation factors (proteins) and platelets
| - Prevent blood loss
141
What happens when the endothelium of a blood vessel is damaged?
Exposes the underlying connective tissue, which contains collagen and a protein called tissue factor
142
What happens when platelets come into contact with exposed collagen?
- They sense this as evidence of injury
| - They release their contents and begin to aggregate
143
What are coagulation factors secreted by? What is their function?
- Secreted by the liver
| - Sense tissue factor and initiate a complex activation cascade
144
What is the endpoint of the coagulation activation cascade?
- Activation of prothrombin to form thrombin by thromboplastin
- Thrombin can then convert fibrinogen into fibrin
- Fibrin acts as a net to capture RBCs and other platelets, which forms a stable clot
145
How is a blood clot broken down?
Plasmin, which is generated from plasminogen
146
In bacterial sepsis, a number of capillary beds throughout the body open simultaneously. What effect does this have on blood pressure?
- Opening up more capillary beds, which are in parallel, will decrease the overall resistance of the circuit
- Cardiac output will increase in an attempt to maintain constant blood pressure
