Cardiovascular l Flashcards
(114 cards)
1
Q
Which take blood away from the heart, arteries or veins?
A
Arteries
2
Q
Which take blood towards the heart, arteries or veins?
A
Veins
3
Q
Name the external layer of the venous circuit (large vein)?
A
Tunica externa
4
Q
Name the middle smooth muscle layer of the venous circuit (large vein)?
A
Tunica media
5
Q
Name the inner layer of the venous circuit (large vein)? This area has 3 of its own layers (Elastin, endothelium, proteins, etc).
A
Tunica interna
6
Q
Why does the venous system contain most of the blood in the body?
A
Contains most of the blood to function as a reservoir from which more blood can be added to the circulation under appropriate conditions (such as exercise). For example, during exercise, there is an increased metabolic demand, and so blood is moved from the venous to arterial pathways).
7
Q
In greatest to least order, describe the distribution of blood in the body.
A
Systemic veins, Lungs/Systemic arteries, Heart, Capillaries
Systemic veins: 60-70%
Systemic arteries: 10-12%
Lungs: 10-12%
Heart: 8-11%
Capillaries: 4-5%
8
Q
Most of the blood volume is in the ______ system.
A
Venous
9
Q
Unlike arteries, which provide _______ to the flow of blood from the heart, veins are able to ________ as they accumulate addition amounts of blood (capacitance vessels).
A
Resistance, expand
10
Q
What is the average pressure in veins vs arteries?
A
Veins : 2 mmHg
Arteries: 100 mmHg
11
Q
The venous press is too low to return blood to the heart. To help veins of the lower limbs return blood, the veins pass between skeletal muscle groups which provide _______ to help move the blood back. What is this described as?
A
Contractions. This is known as the “skeletal muscle pump”. As the muscle contracts, blood is massaged up the vein to bring it to the heart. This is a one way valve, blood does not go back down due to gravity.
12
Q
Describe the mechanism used by the veins to help venous blood from the abdominal and thoracic regions return to the heart.
A
To help the venous blood from the abdominal to thoracic regions, the act of breathing: contraction of the diaphragm and pressure in the abdomen from breathing squeezes the veins and helps the venous blood return to the heart.
13
Q
What helps to ensure the one-way flow of blood back to the heart?
A
Venous valves
14
Q
Describe the phenomenon of varicose veins.
A
- Decreased movement in the leg
- Less skeletal movement pump
- Blood stays in the limb
- 1 way valves pull apart not as well working
- Clots develop
- Cannot deliver nutrients as well - dead tissue
15
Q
In the aorta, the major artery of the heart, and other larger arteries, there are numerous layers of elastin fibres between the smooth muscle cells of the ____________ (middle layer).
A
Tunica media
16
Q
The large elastic artieries (found in the aorta and other large arteries) _________ when the pressure of the blood rises as a result of the ventricles’ contraction.
A
Expand. They expand with increasing levels of blood.
17
Q
Describe the activity of blood in the arteries when the level of blood increases and decreases.
A
The large elastic arteries expand when the pressure of blood rises as a result of ventricles’ contraction. The arteries recoil like a stretched rubber band when the blood pressure falls during relaxation of the ventricles.
18
Q
The elastic recoil of the arteries drives blood during the ______ phase when the heart is resting and not providing pressure.
A
Diastolic.
19
Q
There are over _______ capillaries in the body.
A
40 billion
20
Q
Capillaries provide a total surface area of ___________ for exchanges between blood and interstitial fluid.
A
1000 square miles
21
Q
________ decreases blood flow to the capillary bed, _________ increases it.
A
Vasoconstriction decreases blood flow to the capillary bed, vasodilatation increases it.
22
Q
Unlike the arterial and venous tissues, the walls of the capillaries are composed of how many cell layers?
A
One cell layer
23
Q
A lack of SM and CT makes it ______ to exchange materials between blood and tissues.
A
Easier
24
Q
At the arterial end of capillaries what enter? What exits the venous end of capillaries?
A
At the arterial end of arteries, oxygen, nutrients, hormone, small molecules, etc enter at approximately 37 mmHg. At the venous end of the capillaries, carbon dioxide and wastes exit the capillary at approximately 17 mmHg.
25
Describe the difference between net filtration pressure and net oncotic pressure.
Net filtration pressure describes the difference in hydrostatic pressure. Net oncotic pressure describes the difference is osmotic pressure.
26
At the arterial end of a capillary, blood pressure forces fluid out of the capillary to the fluid _____________. At the venous end, fluid is drawn back into the capillary from neighbouring tissue cells by ________.
Surrounding the tissue cell, by osmotic pressure
27
Describe the location of blood pressure in decreasing order from highest to least blood pressure in the areas of the heart.
Left ventricle, large arteries, small rates and arterioles, Capillaries, venues, large veins
28
Blood flow is a representation of driving forces / __________.
Resistance
29
________________, a 19th century physician helped with the discovery of blood flow.
Jean Leonard Marie Poiseuille
30
Resistance in blood flow depends on three major factors. List them.
1. Tube/blood vessel radius
2. Viscosity of the blood
3. Tube/blood vessel length
31
Describe the trend associated with blood flow and vessel radius.
Lower radius = higher resistance = less blood flow
Increased radius = less resistance = more blood flow
32
How is vessel radius regulated in the heart?
By smooth muscle contraction. Smooth muscle contraction lowers the radius of the blood vessel and lowers blood flow
33
Describe the trend associated with blood flow and blood viscosity.
Higher viscosity = higher friction = higher resistance = decreased blood flow
Lower viscosity = less friction = less resistance = increased blood flow
Increased hematocrit (%of volume plasma in red blood cells) = higher interaction between RBCs = higher clots = higher blood clots = decreased vessel radius = decreased blood flow
34
Describe the trend associated with blood flow and vessel length.
Increased length = increased friction = increased resistance = decreased blood flow
Decreased length = decreased friction = decreased resistance = increased blood flow
35
Describe the distribution of blood within the circulatory system at rest.
Review slide 28.
36
Where does gas exchange occur?
Capillary beds of the lungs and all body tissues.
37
The ______ carries de-oxygenated blood to the hearts right atrium.
Vena cava
38
Which vein carries highly oxygenated blood to the heart?
Pulmonary veins
39
Describe the uniqueness to do with the pulmonary artery and pulmonary vein.
The pulmonary artery is an artery with low O2 but is still considered an artery because it is travelling AWAY from the heart. The pulmonary vein is a vein that carries oxygenated blood to the blood, but it still considered a vein because it carries blood TO the heart.
40
Put these terms in order according to air passageways.
Bronchus
Oral cavity
Pharynx
Larynx
Nasal cavity
Trachea
Lung
1. Nasal cavity
2. Oral cavity
3. Pharynx
4. Larynx
5. Trachea
6. Bronchus
7. Lung
Review slide 30
41
The nasal cavity leads to the _____ (throat), a nasal passage connecting the nasal cavity with the larynx.
Pharynx
42
The larynx is where air is diverted towards the _______ and food is diverted to the esophagus to the _______.
Lungs, stomach
43
Where are the vocal cords located?
The larynx. These are folds in the lining tissue of the larynx.
44
What are the two main functional zones of the respiratory system?
The conducting zone and the respiratory zone.
45
List some functions of the conducting zone of the respiratory system.
- No gas/air exchange
- Humidifies, warms , and transports air to the lungs and then out
46
List the structures involved in the conducting zone of the respiratory system.
- Trachea
- Primary bronchus
- Bronchial tree
- Terminal bronchioles
47
List the structures involved in the respiratory zone of the respiratory system.
- Respiratory bronchioles
- Alveolar sacs (Alveolus)
- Terminal bronchiole
48
Describe the function of the alveolus in the lungs (the respiratory zone).
Increase the surface area of the lungs to increase surface area used for gas exchange.
49
During inspiration and compliance of the respiratory system, describe the action of the chest and the diaphragm.
Breathing in: Chest expands, diaphragm contracts and moves downward.
When we inhale, we increase thoracic volume and decrease intrapulmonary pressure, making it lower than the external pressure. This increases the space in your chest cavity, and your lungs expand into it. The muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.
50
What is intrapulmonary pressure?
Pressure in the alveoli and airway of the lungs.
51
Describe the physical properties of the lungs during inspiration and compliance. Describe compliance and how this applies to breathing and the lungs.
- For inspiration to occur, the lungs must be able to expand when stretched --> They must have high compliance.
Compliance = Distensibility and Stretchability
- Having a high compliance, the lungs must be able to expand under pressure with ease.
- Lung compliance is a change in lung volume per change in transpulmonary pressure = dV/dP
- At any given pressure, there will be greater or less expansion depending on the compliance of the lungs
- Lung disease reduces compliance.
52
During expiration and of the respiratory system, describe the action of the chest and the diaphragm.
- Chest contacts
- Diaphragm relaxes
When you breathe out, or exhale, your diaphragm and rib muscles relax, reducing the space in the chest cavity. As the chest cavity gets smaller, your lungs deflate, similar to how air releases from a balloon.
53
Describe the physical properties of the lungs during expiration and elasticity. Describe elasticity and how this applies to breathing and the lungs.
- For expiration to occur, the lungs must get smaller when tension is released. They must have elasticity.
- Elasticity is the tendency of a structure to return to its initial slide after being distended.
- Because of the high content of elastin proteins, the lungs are very elastic and resist distension.
- The lungs re normally stuck to the chest wall, they are are always in a sate of elastic tension.
54
Describe the trend that applies to tension during inspiration and expiration.
The tension increases during inspiration when the lungs are stretched and is reduced by elastic recoil during expiration.
55
The lungs are always in a state of elastic tension.
Choose the correct statement:
A. The intrapulmonary pressure is greater than the intrapleural pressure outside the lung.
B. The intrapulmonary pressure is less than the intrapleural pressure outside the lung.
A
56
Define transpulmonary pressure.
The difference between the intrapulmonary pressure inside the lung and intrapleural pressure outside the lung to keep the lungs against the chest wall.
57
Describe pneumothorax, a collapsed lung.
Air enters the pleural space, the space between the lung and the chest wall. This leads to increased intrapleural pressure. The transpulmonary pressure to keep the lung against the chest wall is abolished. The lung collapses due to elastic recoil and is no longer attached to the lung wall.
58
Although contraction of the diaphragm and intercostal muscles cause the chest cavity to increase in volume, the lungs cannot inflate unless ______________.
They are attached to the inner wall of the chest cavity.
59
Describe the challenges associated with having a chest wound.
A person who has a chest wound cannot inflate the lung on the wounded side, even though she/he continues to ventilate. Air can be brought in or out, but cannot inflate the lung.
60
The outer lung surface and inner surface of the chest cavity are made with membranes called ____________. These membranes will facilitate expansion.
Pleural membranes
61
Describe the two places where the plural membranes in the lung are attached.
The plural membranes consist of one membrane layer attached to the surface of the lung (visceral), and one membrane layer attached to the inner wall of the chest cavity (parietal).
62
What do the plural membranes produce?
They produce a mucous rich lubricating fluid.
63
Where is the plural fluid (mucous-rich lubricating fluid) found after it is produced by the plural membranes?
It can be found in the space between the two membranes called the pleural space.
64
What is the function of the plural fluid in the lungs?
Holds the two plural membranes together. As the volume of the thoracic cavity changes, so does the volume of the lungs. The pleural fluids the "glue" that holds the lungs attached to the inner wall of the thoracic cavity. The plural fluid is also the lubricant that allows the lungs to slide easily within the thoracic cavity as they inflate and deflate.
65
What are the physical properties of the lungs?
1. Inspiration and Compliance
2. Expansion and elasticity
3. Surface Tension
4. Lung volumes and capacities
66
Surface tension in the lungs is exerted by fluid in the ______.
Alveoli
67
How is surface tension in the lungs created?
It is created by the attraction between water molecules, which pulls them together. As the number of H-bonds increase, the surface tension inside the cells increases. This surface tension would cause the alveoli to collapse.
68
Fluid from the alveoli contains surfactant. Describe the composition of this fluid.
It is a mixture of phospholipids and hydrophobic surfactant proteins.
69
Surfactant is secreted into the alveoli by ________.
Type ll Alveolar cells.
70
Surfactant lowers surface tension in the alveoli. What benefit does this present?
This prevents the alveoli from collapsing during expiration.
71
Describe 'Respiratory Distress Syndrome' .
Surfactant is produced late in fetal life. Premature babies are sometimes born with lungs that lack sufficient surfactant and their alveoli are collapsed as a result.
72
Define tidal volume.
Volume of gas inspired or expired in an unforced respiratory cycle.
73
Define inspiratory reserve.
Maximum volume of gas that can be inspired during forced breathing in addition to tidal volume.
74
Define expiratory reserve.
Max volume of gas that can be expired during forced breathing in addition tidal volume.
75
Define residual volume.
Volume of gas remaining in lungs after max expiration.
76
Define total lung capacity.
Total amount of gas in the lungs after a max inspiration. The sum of all four lung volumes.
77
Define vital capacity.
Max amount of gas expired after a max inspiration. (Everything but residual)
78
Define inspiratory capacity.
Max amount of gas that can be inspired after a normal tidal expiration. (Tidal + inspiratory)
79
Define functional residual capacity.
The amount of gas remaining in the lungs after a normal tidal expiration. (expository reserve + residual)
80
List the places of anatomical dead space (dead volume). This is where no gas exchange occurs. There is approximately 150 mL of dead space in the body.
- Nose
- Mouth
- Larynx
- Trachea
- Bronchi
- Bronchioles
81
What is the percentage of fresh air reaching the alveoli if the anatomical dead space is 150 mL and the tidal volume is 500 mL?
150 mL is dead space therefore:
500-150 = 350 mL
350/500 mL x 100 = 70%
82
What is the percentage of fresh air reaching the alveoli if the anatomical dead space is 150 mL and the total volume is 2000 mL?
2000-150 mL = 1850 mL reaching alveoli
1850/2000 x 100 = 93%
83
If the tidal volume increases, what happens to the percentage of fresh air reaching the alveoli with a dead volume of 150 mL?
The percentage increases.
84
What is the role of hemoglobin in the respiratory and cardiovascular system?
- Hemoglobin (Hb) contains iron and is present in the cytoplasm of rd blood cells.
- It is a binding agent and releases iron and oxygen into the tissues of other cells.
- It chemically combines with O2, but can also release the gas when the cells need it.
- Hb acts as an O2 shuttle from the lungs to the body tissues.
85
The hemoglobin molecule is composed of ____ beta chains, _____ alpha chains, and ____ heme group(s).
2 beta, 2 alpha, 1 heme group
86
1 heme group can form how many how many bonds to oxygen?
4 bonds
87
What is the role of CO2 in regulating the binding of O2 with hemoglobin in the lungs?
In the lungs:
- CO2 diffuses from the blood to the alveoli
- Lowers the blood CO2 levels
- This reduces the acidity of blood in the lungs
- Higher pH
- Lower CO2 higher O2
- Hemoglobin has a higher affinity for oxygen
88
What is the role of CO2 in regulating the binding of O2 with hemoglobin in the tissues?
In the tissues:
- Blood CO2 levels are high because the cells produce the gas as an excretory product
- O2 levels are low because it is being used by the cells
- Increases the acidity of the blood in the tissues
- Lowers pH
- Oxygen unloading to be taken up by the tissues
89
The acidity of the plasma (which is directly related to plasma CO2 content) determines either O2 combines with Hb to form _____________.
Oxyhemoglobin
90
When there is low acidity and a higher pH in the lungs, what happens to Hb?
O2 binds with Hb to form oxyhemoglobin.
91
When there is high acidity and lower pH in the tissues, what happens with oxygen and Hb?
O2 is released from oxyhemoglobin.
92
Hb also has binding sites for ______. It acts as a shuttle for this compound from body tissues to lung.
CO2
93
Describe The Bohr Effect.
The Bohr effect is a phenomenon first described in 1904 by the Danish physiologist Christian Bohr. Hemoglobin's oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide.
94
In the lungs O2 is _______ the blood and CO2 is ______ the blood.
Entering, leaving
95
How does oxygen enter the blood in the lungs (UPTAKE)?
-O2 dissolves in the lining fluid film of the alveoli, diffuses through the walls of the alveoli and blood capillaries into the plasma.
- O2 then diffuses into RBCs and combines chemically with Hb to form oxyhemoglobin.
96
Where does oxyhemoglobin formation occur? Why?
In the lungs because CO2 levels in the lungs are low.
97
How is oxygen released in the tissues?
- O2 is released from oxyhemoglobin and diffuses into body tissues.
- Disassociation of Hb and O2 occurs in the tissues because plasma CO2 levels in the body tissues are high (as pH decreases it is more acidic).
98
In the body tissues, O2 is being _______ by the cells and CO2 is being _______ by the cells.
Used, produced
99
Where does the dissociation of oxyhemoglobin take place? Why?
In the tissues because plasma CO2 levels in the body tissues are high and as pH increases it is more acidic.
100
Blood acidity ____ as CO2 diffuses from the plasma to the alveolar sac allowing O2 to combine with Hb to form oxyhemoglobin (HbO2).
Decreases (pH up)
101
Blood acidity ______ as CO2 diffuses from body cells to the plasma causing oxyhemoglobin (HbO2) to dissociate into Hb and O2; the O2 diffuses into the body cells.
Increases (pH lowers)
102
CO2 is a byproduct of ________. It is constantly produced and there is constant movement, by diffusion, from body cells into the blood plasma.
Metabolism
103
How much of the CO2 in the blood is dissolved into molecular CO2?
About 10%
104
Approximately how much CO2 is also carried attached chemically to Hb?
Approximately 20%
105
What are carbamino compounds?
When Co2 is chemically attached to Hb
106
Co2 transport: As CO2 diffuses from body cells into the plasma, it diffuses into RBCs and is converted into _______ (HCO3-).
Bicarbonate ion
107
What enzyme present in RBCs is responsible for converting CO2 from body cells into the plasma into bicarbonate ions?
Carbonic anhydrase
108
Give the equation of the bicarbonate equation in RBCs (spontaneous).
CO2 + H2O --> H2CO3 --> H+ + HCO3-
109
In the lungs, CO2 is lost due to alveolar air sacs, give the equation of biocarbonate and hydrogen back to CO2.
HCO3- + H+ --> H2CO3 --> CO2 + H2O
110
What is the enzyme that works in the CO2 conversion to bicarbonate in red blood cells (the bicarbonate equation)
Carbonic anhydrase
111
During exercise, there is a simultaneous ________ in O2 consumption and CO2 production by muscles. This is matched with an increase in lung ventilation.
Increase.
112
What are the two proposed mechanisms that may explain the increased ventilation during exercise? Describe them.
1. Neurogenic
- Sensory nerve activity from exercising limbs may stimulate respiratory muscles
- Input from the cerebral cortex may stimulate the brain stem centres to modify ventilation
- HELP EXPLAIN THE IMMEDIATE INCREASE IN VENTILATION THAT OCCURS AS EXERCISE BEINGS
2. Humoral (Chemical)
- PCo2 and pH in the region of chemoreceptors may be diffrent in downstream regions
- Variations cannot be detected by blood samples and can still stimulate chemoreceptors
- HELP EXPLAIN THE CONTINUED RAPID AND DEEP VENTILATION AFTER EXERCISE HAS STOPPED
113
Describe te lactate threshold and endurance training.
- The cardiopulmonary system may not deliver adequate amounts of O2 at the begging of a workout
- Time lag to make CV adjustments
- During this time muscles metabolize anaerobically
114
What is the lactate threshold and what is it used for?
- Used for continued heavy exercise
Maximum rate of oxygen consumption that can be attained before anaerobic metabolism produces a rise in blood lactate levels
- Rise in levels du to aerobic limitation of the muscles, not the CP system
