Pulmonary Flashcards
(167 cards)
1
Q
What is the main function of the lungs?
A
Gas exchange, bringing oxygen into the body and expelling carbon dioxide.
2
Q
What is the function of the diaphragm?
A
It is a muscle that contracts involuntarily but also has voluntary control, when it contracts it pulls downward and in coordination with the chest muscles pulling the chest open it helps to suck in air to the lungs like a vacuum during inhalation. When it relaxes it moves backup and allows the lungs to recoil and push the air out
3
Q
Should food enter the larynx, the esophagus, or both?
A
The esophagus, the epiglottis covers the larynx to seal it off while eating so that only air should enter the larynx.
4
Q
What is the path of air from the larynx to the alveoli of the lungs?
A
Larynx> trachea > mainstem (primary) bronchi > smaller bronchi >conducting bronchioles > terminal bronchioles > respiratory bronchioles > alveoli
5
Q
How many lobes are in the right lung and how many in the left lung? What are the names of the lobes?
A
The right lung has three lobes - upper lobe, middle lobe, and lower lobe
The left lung has just an upper lobe and lower lobe
6
Q
Is the smooth muscle of the respiratory airways innervated by the somatic or autonomic nervous system?
A
Autonomic
7
Q
Which receptors are in the smooth muscle of the trachea and bronchi? Which are stimulated by the sympathetic nervous system, and which are stimulated by the parasympathetic nervous system and what do they do?
A
beta 2 adrenergic receptors- sympathetic NS, increase diameter of airways
muscarinic receptors- parasympathetic NS, decrease diameter of airways
8
Q
What is the mucociliary escalator?
A
Mucus is secreted by the lining of the large airways to help trap particles to prevent them from getting into the lungs, then ciliated cells beat rhythmically together to move the mucus and any trapped particles from the air towards the pharynx where they can either be spit out or swallowed.
9
Q
Where are alveoli?
A
The terminal structures of the airway system, balloon like structures organized in clusters, where air exchange occurs. Thin epithelial cells line the walls of the alveoli which makes gas exchange easier
10
Q
What types of cells make up the alveoli and what are their functions?
A
Type I and Type II pneumocytes
Type I pneumocytes are the primary cell type in the alveolus and are the cells responsible for exchange of O2 and CO2
Type II pneumocytes are the cells that produce and secrete surfactant
11
Q
What is the function of surfactant?
A
Surfactant helps decrease the surface tension within the alveoli and keeps them open. They can also transform into type I pneumocytes to replace damaged cells
12
Q
How does gas exchange occur at the alveoli?
A
The pulmonary arteries bring deoxygenated blood to the capillaries lining the alveoli, inhaled O2 diffuses from the alveoli to the capillaries and CO2 from the blood diffuses into the alveoli to be exhaled, the pulmonary veins then bring the oxygenated blood back to the heart to pump out to the body
13
Q
What is tidal volume?
A
The volume of air moving in and out with each breath during normal, quiet breathing
14
Q
What is inspiratory reserve volume?
A
The volume of air that can be maximally inhaled above the tidal volume
15
Q
What is expiratory reserve volume?
A
The volume of air that can be maximally exhaled below the tidal volume
16
Q
What is residual volume?
A
The volume of air remaining in the lungs after a maximal exhalation
17
Q
What is functional residual capacity?
A
Expiratory reserve volume + residual volume= functional residual capacity
18
Q
What is inspiratory capacity?
A
Tidal volume + inspiratory reserve volume= inspiratory capacity
19
Q
What is vital capacity?
A
Inspiratory capacity + expiratory reserve volume= vital capacity
20
Q
What is total lung capacity?
A
Vital capacity + residual volume= total lung capacity
21
Q
What are alveoli?
A
The tiny air sacs in the lungs where gas exchange happens
22
Q
How do alveoli overcome surface tension to stay open?
A
By producing surfactant, which is a phospholipoprotein that reduces the surface tension, keeping the alveoli open to allow gas exchange to occur
23
Q
What does difficulty with inflating individual lung alveoli result in?
A
Reduced lung compliance, which is the ability of the lung to stretch and inflate
24
Q
What type of cells primarily line the wall of the alveoli?
A
Type I pneumocytes
25
What is the function of Type II pneumocytes?
Produce and secrete surfactant in the alveoli to overcome surface tension that could cause the alveoli to collapse. Surfactant helps to keep the alveoli open
26
What is the definition tidal volume?
The volume of air moving in and out with each breath during normal,quiet breathing
27
What is the definition of respiratory rate? What is a normal respiratory rate for adults?
The respiratory rate is the number of breaths a person takes per minute
Normally around 15 breaths per minute at rest for an adult
28
What is physiologic dead space?
The volume of air lost due to air trapped in airways (anatomical deadspace) and air lost to malfunctioning alveoli. This volume of air does not participate in gas exchange.
29
What is minute ventilation?
The total rate of air movement into and out of the lungs per minute but does not account for physiologic dead space
30
What is alveolar ventilation?
The total rate of air that functionally participates in gas exchange per minute and does account for physiologic dead space
31
If carbon dioxide production is constant, then the partial pressure of alveolar carbon dioxide is determined by what?
Alveolar ventilation
32
What would an increase in alveolar ventilation cause the alveolar partial pressure of carbon dioxide to do?
Decrease
33
What would a decrease in alveolar ventilation cause the alveolar partial pressure of carbon dioxide to do?
Increase
34
Is alveolar partial pressure of carbon dioxide always greater than, less than,or equal to the arterial partial pressure of carbon dioxide?
Equal to
35
If carbon dioxide production is doubled, what happens to the ventilation rate to keep a constant partial pressure of carbon dioxide in the alveoli?
It also doubles
36
Is hyperventilation or hypoventilation characterized by an increased pO2, a decreased pCO2, and an increased blood pH?
Hyperventilation
37
Is hyperventilation or hypoventilation characterized by a decreased pO2, anincreased pCO2, and a decreased blood pH?
Hypoventilation
38
What is the path of blood in the pulmonary circulation?
Deoxygenated blood from the right ventricle > pulmonary trunk > pulmonary arteries > pulmonary arterioles > pulmonary capillaries > gas exchange at the capillaries with the alveoli > pulmonary veins > oxygenated blood back to the heart into the left atrium
39
What is pulmonary blood flow?
The volume of blood that’s pumped out of the right ventricle over time, usually in 1 minute. Pulmonary blood flow is the cardiac output of the right ventricle
40
Is the blood pressure and resistance in the pulmonary circulation higher or lower than that of the systemic circulation?
Normally much lower in the pulmonary than in the systemic circulation.
41
What is the relationship between pulmonary blood flow and resistance in the pulmonary blood vessels?
Inversely proportional, as resistance goes up pulmonary blood flow goes down
42
How could the pulmonary blood vessels contribute to decreased pulmonary blood flow?
By changing the resistance of the vasculature, a decrease in the diameter of the arterioles from vasoconstriction causes an increase in resistance, and a decrease in blood flow
43
How could the pulmonary blood vessels contribute to increased pulmonary blood flow?
By changing the resistance of the vasculature, an increase in the diameter of the arterioles from vasodilation causes a decrease in resistance, and an increase in blood flow
44
What is the difference between the terms ventilation and respiration?
Ventilation addresses the exchange of air between the atmosphere and the lungs during inspiration and expiration while respiration addresses the exchange of gases between the blood and the cells
45
Is breathing primarily under voluntary or involuntary control?
Primarily involuntary control from the respiratory center but can be voluntarily controlled through commands from the cerebral cortex
46
Which phase of breathing is active, inspiration or expiration?
Inspiration is an active process that involves the diaphragm and the external intercostal muscles during quiet breathing.
47
What is atmospheric pressure?
The pressure of the air in the environment
48
What is alveolar pressure?
The pressure inside the alveoli
49
What is intrapleural (aka intrathoracic) pressure?
The pressure of the fluid inside the pleural cavity that surrounds the lungs
50
What does Boyle’s law state? What is an example of this in action?
At a constant temperature, pressure and volume are inversely related to each other, so when the alveolar pressure decreases, more air will enter the lungs, increasing the air volume
51
Does air move up or down a pressure gradient?
Air always moves down a pressure gradient
52
What signals the need for a new breathing cycle?
Variations in arterial pressure of oxygen PaO2, carbon dioxide PaCO2, or arterial pH
53
What is a normal arterial pressure of oxygen, PaO2?
100mmHg
54
What is a normal arterial pressure of carbon dioxide, PaCO2?
40mmHg
55
What is a normal arterial pH?
7.4
56
How do variations in arterial pressure of oxygen PaO2, carbon dioxide PaO2, or arterial pH initiate changes in breathing
Chemoreceptors sense changes in these factors and send signals to the respiratory center in the brainstem
57
What three major respiratory groups of neurons are found in the respiratory center in the brainstem?
Dorsal respiratory group
Ventral respiratory group
Pontine respiratory group
58
How does the respiratory center typically initiate breathing?
When the dorsal respiratory group in the respiratory center receives information regarding the increase of PaCO2, it sends a command through the phrenic nerve to the diaphragm and through the intercostal nerves to the external intercostal muscles
59
How does the respiratory center support when oxygen requirements are higher like during exercise?
The respiratory center prolongs the action potentials in the phrenic nerve to prolong the contraction of the diaphragm and initiate the activation of accessory respiratory muscles like the sternocleidomastoid and scalene muscles
60
How does the respiratory center limit overventilation with vigorous exercise?
To prevent inhalation occurring when the lungs are already fully inflated, the respiratory center limits the burst of action potentials in the phrenic nerve, making the diaphragm contract less, stopping inspiration and allowing for expiration
61
When does expiration begin in the breathing cycle?
When inspiration ends
62
How is it that expiration is normally a passive process?
The diaphragm relaxes and the air leaves the lungs due to their elasticity. The lungs squeeze back to their initial size and put pressureon the volume of air inside the alveoli. This makes the alveolar pressure increase higher than the atmospheric pressure, creating a pressure gradient that pushes the air out of the lungs.
63
How does the respiratory center support forced exhalation?
The respiratory center is activated and sends signals that decrease the duration of inspiration, leaving more time for a longer expiration.
64
What is hyperventilation?
An increase in breathing frequency and volume above normal
65
What is hypoventilation?
A decrease in breathing frequency and volume below normal
66
What three main factors influence airway resistance?
Air viscosity, airway length, airway radius
67
How does air viscosity influence airway resistance?
As air viscosity increases, airway resistance increases.
68
How does airway length influence airway resistance?
Airway length, the relationship with airway resistance is directly proportional, longer airways have higher resistance than shorter airways.
69
How does airway radius influence airway resistance?
Airway radius, the relationship is inversely proportional, and the radiusis raised to the power four
70
Which of the three main factors that influence airway resistance have the largest effect on airway resistance?
Changes in airway radius has the largest effect on airway resistance, the relationship is inversely proportional, and the radius is raised to the power four. Also, unlike air viscosity and airway length, airway radius can change from minute to minute
71
Which of the three main factors on airway resistance tend not to change much over time?
Both air viscosity and airway length don’t change much overtime, so they don’t contribute that much to changes in airway resistance in real life
72
Relative to the airway from the trachea down to the terminal bronchioles how does the airway resistance change?
Low resistance in the trachea with increasing resistance into the bronchi and bronchioles with resistance decreasing again in the very small terminal bronchioles due to the overall increased cross-sectional area
Each individual terminal bronchiole’s resistance to airflow is high, when you consider all the parallel terminal bronchioles and their increased cross-sectional areas, overall resistance is actually the lowest in the respiratory tract
73
What effect does the parasympathetic nervous system have on the bronchi to control airway resistance and flow?
Bronchoconstriction to increase resistance and decreases airflow
74
What effect does the sympathetic nervous system have on the bronchi to control airway resistance and flow?
Bronchodilation to decrease resistance and increases airflow
75
What is oxygen content?
The amount of oxygen in a certain volume of blood, typically 100mL. It is the sum of the hemoglobin bound oxygen in the blood plus dissolved oxygen in the blood plasma
76
What is oxygen binding capacity?
The maximum amount of oxygen that can be bound to hemoglobin
77
What is hemoglobin?
The main protein found inside of red blood cells that can bind and transport oxygen.
78
What are the two ways that oxygen is transported in the blood?
Dissolved in the blood plasma and bound to hemoglobin
79
How is most of the oxygen transported in the blood?
Bound to hemoglobin inside red blood cells
80
How many oxygen molecules can bind to each hemoglobin molecule in the blood?
4
81
Is hemoglobin always completely bound by 4 oxygen molecules?
No, hemoglobin isn’t always 100% saturated, a hemoglobin might have no O2 bound (0% saturated), one oxygen bound (25% saturated), two bound (50% saturated), three bound (75% saturated), or four bound(100% saturated)
82
What is the relationship between the amount of oxygen that’s bound to hemoglobin is and the amount of oxygen dissolved in the blood?
Directly proportional to one another
83
How is oxygen delivery calculated?
Oxygen delivery is the oxygen content multiplied by the cardiac output (the amount of blood that’s being pumped out by the heart each minute)
84
How is cardiac output calculated?
The stroke volume, the volume of blood pumped per beat from the left ventricle of heart, expressed as mL per heartbeat; multiplied by the heart rate in beats per minute
85
What does the oxygen-hemoglobin dissociation curve show?
How the hemoglobin saturation with oxygen (SO2,), is related to the partial pressure of oxygen in the blood (PO2).
86
What is hemoglobin?
The main protein within red blood cells, and it’s made of four globin subunits, each containing a heme group capable of binding one molecule of O2
87
Is hemoglobin always fully bound by oxygen?
No, each hemoglobin protein can bind 4 molecules of oxygen, but each hemoglobin isn’t always 100% saturated or bound by oxygen.
88
What is a 0% saturated hemoglobin molecule called? What is its state shape?
Deoxyhemoglobin, tense state shape, or T-state
89
What is a 25-100% saturated hemoglobin molecule called? What is its state shape?
Oxyhemoglobin, changing to its relaxed state, or R-state
90
What is pulse oximetry?
A technique that uses the absorption of light wavelengths by hemoglobin to figure out the average oxygen saturation across millions of hemoglobin proteins since hemoglobin absorbs different wavelengths of light as it gets more oxygenated.
91
What is the main factor that influences oxygen saturation?
The partial pressure of oxygen in the blood, at a partial pressure of 25mmHg, hemoglobin proteins might be 50% saturated, called P50; and at a partial pressure of 100mmHg, they might be 98% saturated, meaning most are fully saturated.
92
What does the sigmoidal shape of the oxygen-hemoglobin dissociation curve mean
That hemoglobin has an increasing affinity for O2 as the number of bound O2 molecules goes up.
93
What is positive cooperativity?
That hemoglobin has an increasing affinity for O2 as the number of bound O2 molecules goes up. Binding a 4th O2 molecule is much easier than binding a first O2 molecule
94
What are factors that can cause hemoglobin’s affinity for O2 to change?
Change in PCO2 levels, pH, temperature, 2, 3-DPG
95
What happens to hemoglobin affinity for O2 with increased PCO2? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 decreases and the curve shifts right, a higher PO2 is needed to bind O2 and saturate hemoglobin
96
What happens to hemoglobin affinity for O2 with increased temperature? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 decreases and the curve shifts right, a higher PO2 is needed to bind O2 and saturate hemoglobin
97
What happens to hemoglobin affinity for O2 with increased pH? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 increases and the curve shifts left, a lower PO2 is needed to bind O2 and saturate hemoglobin
98
What happens to hemoglobin affinity for O2 with increased 2,3- DPG? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 decreases and the curve shifts right, a higher PO2 is needed to bind O2 and saturate hemoglobin
99
What happens to hemoglobin affinity for O2 with decreased PCO2? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 increases and the curve shifts left, a lower PO2 is needed to bind O2 and saturate hemoglobin
100
What happens to hemoglobin affinity for O2 with decreased temperature? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 increases and the curve shifts left, a lower PO2 is needed to bind O2 and saturate hemoglobin
101
What happens to hemoglobin affinity for O2 with decreased pH? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 decreases and the curve shifts right, a higher PO2 is needed to bind O2 and saturate hemoglobin
102
What happens to hemoglobin affinity for O2 with decreased 2,3- DPG? What happens to the oxygen-hemoglobin dissociation curve?
Hemoglobin affinity for O2 increases and the curve shifts left, a lower PO2 is needed to bind O2 and saturate hemoglobin
103
Which side of the heart supply blood to the pulmonary capillaries?
Right side
104
Which side of the heart do the pulmonary capillaries deliver blood to?
Left side
105
How does gas exchange between blood and alveoli, and between blood and tissue cells occur?
By simple diffusion.
106
What are the primary three components of alveolar gas exchange?
The surface area of the alveolo-capillary membrane, the partial pressure gradients of the gasses, and the matching of ventilation and perfusion.
107
Specifically, where in the alveoli does gas exchange occur?
Alveolar-capillary membrane, where the cell lining of the alveolar cells meets the endothelial cell lining of the pulmonary capillaries
108
What is the relationship between surface area of the alveolar-capillary membrane and alveolar gas exchange?
Greater surface area yields greater gas exchange (greater diffusion),less surface area results in decreased diffusion
109
How does the partial pressure gradients of the gasses affect alveolar gas exchange?
The driving force for diffusion is the partial pressure difference of the gasses across the membrane, not the concentration difference. The diffusion of oxygen and carbon dioxide are driven across the respiratory membrane by their partial pressure gradients
110
What impact would an increased thickness of the alveolar-capillary wall have on gas exchange?
The rate of diffusion would decrease with increased wall thickness
111
Is the partial pressure difference between the alveolar air and in the pulmonary arteries greater for oxygen or carbon dioxide?
Oxygen
112
A steep oxygen partial pressure gradient occurs through the respiratory membrane because the partial pressure of oxygen in the alveolar air is (greater/less) ________ than the partial pressure of oxygen in the pulmonary arteries
Greater
113
For a fixed amount of gas kept at a fixed temperature, if volume increases what happens to the pressure? (Boyle’s Law) How can this be applied to inspiration and expiration?
If volume increases, pressure decreases; if volume decreases, pressure increases
In inspiration, lung volume increases, which decreases alveolar pressure, creating a negative pressure gradient that allows oxygen to flow into the lungs.
In expiration, the alveolar pressure increases, and the lung volume decreases, making the air exit the lungs.
114
What is the relationship between the amount of gas that dissolves in a liquid and the partial pressure of gas in equilibrium with that liquid at a constant temperature? (Henry’s Law) How is this applied to respiration?
The amount of a gas that dissolves in a liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid
Within the lungs, oxygen and carbon dioxide diffuse between the air in the alveoli (a gas) and the blood (a liquid). Gas from the alveoli can be forced to dissolve into blood, if there is enough pressure applied and a controlled volume
115
Describe the ventilation perfusion balance.
Ventilation refers to the amount of gas that reaches the alveoli while perfusion refers to the blood flow in pulmonary capillaries.
Perfusion can change with arterial constriction and dilation.
Ventilation can change with bronchiolar constriction and dilation.
PCO2 controls ventilation by changing bronchiolar diameter, and PO2 controls perfusion by changing arteriolar diameter of the pulmonary capillaries
116
When alveoli have high PO2 and low PCO2 what happens in the bronchioles and in the pulmonary capillaries?
The bronchioles serving the alveoli constrict because there isn’t much CO2 that needs to be removed
The pulmonary capillaries dilate allowing the blood to pick up the O2
117
When alveoli have low PO2 and high PCO2 what happens in the bronchioles and in the pulmonary capillaries?
The bronchioles serving the alveoli dilate because the CO2 needs to be removed.
The pulmonary capillaries constrict because there is relatively low O2 to be picked up and that allows blood to go to other alveoli that may have more O2
118
What is the relationship of the partial pressure and diffusion gradients between external respiration and internal respiration?
The gradients are reversed
With external respiration the partial pressure of O2 is high in the alveoli and low in the blood and the partial pressure of CO2 is low in the alveoli and high in the blood. This allows O2 to diffuse into theblood and CO2 to diffuse into the alveoli
With internal respiration the partial pressure of O2 is low in the tissues and high in the blood and the partial pressure of CO2 is high in the tissues and low in the blood. This allows O2 to diffuse into the tissues and CO2 to diffuse into the blood.
119
What are four general functions of blood?
Move nutrients and waste around the body, regulate our pH level, help prevent infections, and help prevent the loss of blood during an injury through clotting.
120
After blood is centrifuged, which three distinct layers form, approximately what percept of each are present, and what does each contain?
~45%-the erythrocytes or red blood cells at the bottom (aka hematocrit)
<1%- the buffy coat- contains platelets and immune cells in the middle
~55%- the plasma at the top (90% water, the rest is proteins, electrolytes, and dissolved gases)
121
What is the main function of erythrocytes?
To carry oxygen to tissues and bring carbon dioxide to the lungs
122
What is the shape of erythrocytes? What does this shape help with?
Erythrocytes are shaped liked thin biconcave discs, it makes them flexible enough to fit through very small blood vessels and increases their surface area which helps them conduct gas exchange efficiently.
123
Do erythrocytes have a nucleus or other organelles?
No, they have no nucleus or other organelles like the nucleus, this creates more room for hemoglobin proteins which carry oxygen.
124
Approximately how long to erythrocytes live?
About 120 days
125
Where are erythrocytes regenerated?
In the bone marrow
126
What percent whole blood volume is taken up by the buffy coat? What does this consist of?
<1%, it contains platelets and leukocytes, or white blood cells, most ofthe volume being taken up by the leukocytes.
127
Where is the main role of platelets?
Clotting, they clump together and form a plug that helps seal off a damaged blood vessel and prevent blood loss.
128
Do leukocytes contain organelles?
Yes, they are the only complete cells in blood, they have a nucleus and all the usual organelles
129
What are the general functions of leukocytes?
They help to ward off pathogens like bacteria and viruses, destroy cancerous cells, and neutralize toxins
130
Which leukocytes are called granulocytes? Why are they called this?
Neutrophils, eosinophils, and basophils are all granulocytes. They contain tiny sacs called granules that are filled with inflammatory molecules.
131
What are the general functions of neutrophils?
Neutrophils are the most common granulocyte, about 60% of the leukocytes and these are usually the first to respond to an infection
132
What are the general functions of eosinophils and basophils?
They are granulocytes that make up about 2-5% of leukocytes
Eosinophils are largely responsible for fighting off parasitic infections
Basophils are help in allergic reactions.
133
Which leukocytes do not have granules?
Lymphocytes and monocytes are leukocytes that do not have granules they include B cells, T cells, and Natural killer cells, and make up about 35% of leukocytes
134
What are the general functions of lymphocytes?
Lymphocytes are responsible for the adaptive immune response which includes antibody production and is what allows our immune system to have “memory” so that we can effectively respond to pathogens that have caused infections in the past
135
What are the general functions of monocytes?
Monocytes make up about 5% of the leukocytes - these cells help gobble up bacteria or other pathogens via phagocytosis
136
What is diapedesis?
A process where leukocytes can leave the blood, slipping in between endothelial cells that line the blood vessels and enter tissues.
137
What is plasma comprised of?
Plasma makes up approximately 55% of whole blood and is acellular. About 90% of plasma is water, and the rest is composed of proteins, electrolytes, and dissolved gases.
138
What is the most abundant protein found in blood? What are its primary functions?
Albumin, helps maintain oncotic pressure and albumin is a transport protein - it shuttles fatty acids, calcium, lipid soluble hormones, and even some medications around the body.
139
What is fibrinogen?
An abundant plasma protein involved in clot formation for damaged vessels. Fibrinogen helps platelets attach to one another to form the initial platelet plug.
140
What is serum plasma?
A plasma sample with all clotting factor proteins removed
141
What electrolytes are in plasma? What is their general combined function?
Sodium, potassium, calcium, bicarbonate, and chloride. These electrolytes play vital roles in maintaining normal acid base physiology in the blood, and help regulate blood osmolarity
142
Other than proteins and electrolytes, what other solutes are found in the plasma?
Hormones, nutrients like glucose, and respiratory gases like oxygen and carbon dioxide that are dissolved in the blood
143
What is erythropoietin
A hormone that stimulates the production of erythrocytes or red bloodcells (RBCs) in the bone marrow
144
Where is erythropoietin produced and where does it stimulate the production of red blood cells?
It is produced in the kidneys primarily and the liver. It travels through the blood to the bone marrow where it stimulates immature cells to transform into mature red blood cells.
145
How is erythropoietin production timed?
Production of erythropoietin by the kidneys is constant so the production of mature RBCs is constant. It can be increased if needs change
146
What happens to erythropoietin production when there is decreased oxygen delivery to the tissues?
The kidneys can increase erythropoietin production to increase RBC production
147
What role does erythropoietin play in preventing apoptosis in immature RBCs?
Erythropoietin prevents immature red blood cells from killing themselves by apoptosis, without erythropoietin developing red blood cells die via apoptosis
148
What are two factors that can contributed to decreased oxygen delivery to the tissues?
Decreased blood flow or decreased blood oxygen content
149
Which of the two factors that can contributed to decreased oxygen delivery to the tissues can be helped by increased RBC production?
Decreased blood oxygen content can be improved by increased RBC production, decreased blood flow would not improve with increased RBC production
150
Which organ distinguishes between decreased blood flow or decreased blood oxygen content as a causative factor for decreased oxygen delivery to the tissues?
The kidneys can determine if decreased O2 delivery is due to decreased blood flow or decreased O2 content. If due to decreased O2 content the kidneys produce more erythropoietin, and more RBCs are produced to improve O2 content
151
Why is exogenous erythropoietin sometimes taken by athletes?
Erythropoietin (EPO) is sometimes used as an enhancement agent by athletes who want extra red blood cells to help them in sports like long-distance running and cycling. This is an example of doping in sports and is not healthy or ethical
152
The process of wound healing depends on the formation of what?
A blood clot
153
What is hemostasis?
How the body prevents blood loss to a blood vessel following injury
154
What is primary hemostasis?
The stage of hemostasis where the platelets clump up together and form a plug around the site of injury
155
What is secondary hemostasis?
The stage of hemostasis where the platelet plug is reinforced by a protein mesh made up of fibrin to help keep it together
156
What impact would a decrease in platelet number have on bleeding time?
A decrease in platelet number would increase bleeding time
157
What are the five steps of primary hemostasis?
To achieve the clumping up of platelets the five steps of primary hemostasis are: endothelial injury, exposure, adhesion, activation ,and aggregation
158
Following endothelial injury, what do the smooth muscles surrounding the blood vessels near the site of injury do?
Nerves that are attached to endothelial cells and the smooth muscle cells detect the injury and triggers a reflexive contraction of the smooth muscles. This makes the vessel more narrow to reduce blood flow and ultimately decrease blood loss through the damaged artery
159
What is the impact of increased lactic acid in the bloodstream?
It can lower pH levels in the bloodstream
160
What structures detect increased lactic acid in the bloodstream?
Peripheral chemoreceptors, which are specialized neurons located in the walls of the carotid arteries and the aortic arch
161
What do peripheral chemoreceptors do when they detect decreased blood pH?
These neurons fire more impulses, notifying the respiratory centers in the brainstem that they have to increase the respiratory rate and depth of breathing, called hyperventilation.
162
What is the effect of exercise induced hyperventilation?
More oxygen reaches the alveoli, which are the tiny air sacs where gas exchange occurs.
163
What is the effect of more oxygen in the alveoli due to exercise induced hyperventilation?
It leads to pulmonary vasodilation, reducing the pulmonary vascular resistance, so more blood flows through. We get a more even distribution of pulmonary perfusion, and increased efficiency in gas exchange between the alveoli and the pulmonary capillaries, so more oxygen gets in the blood, and more carbon dioxide leaves the blood.
164
What happens in the cardiac centers in the brainstem when peripheral chemoreceptors firing increases?
The cardiac centers in the brainstem decrease the parasympathetic stimulation to the heart and increase sympathetic stimulation - aka the fight or flight response.
165
What happens to heart rate and cardiac contractility with increased sympathetic stimulation?
When epinephrine gets to the heart, it binds to the adrenergic receptors of the heart muscle, making heart rate and contractility increase. The heart muscle fibers contract faster and stronger and the amount of blood the heart pumps out in a minute increases
166
What happens to the blood vessels to the kidneys, liver, and gastrointestinal system with increased sympathetic stimulation?
Epinephrine causes systemic vasoconstriction, which means visceral blood vessels contract, so there’s reduced blood flow to the kidneys, liver and the gastrointestinal system.
167
What happens to PaO2 and PaCO2 in arterial and venous blood during exercise?
Mean arterial oxygen, and mean carbon dioxide partial pressures, or PaO2 and PaCO2 for short, stay constant. In venous blood, however, oxygen partial pressure is low, but carbon dioxide partial pressure is high during exercise compared to rest.
