circulation and gas exchange 2 Flashcards
1
Q
what is blood?
A
Blood is a connective tissue with cells suspended in plasma
2
Q
what is serum?
A
Blood plasma with clotting factors removed is called serum
3
Q
what are the types of cells suspended in blood as well as their functions?
A
-white blood cells (leukocytes): defence and immunity
-platelets: blood clotting
-red blood cells (erythrocytes): transport of O2 and some CO2
4
Q
what are the components of plasma as well as their functions?
A
5
Q
what’s in plasma?
A
- carries the cells and cell fragments (red and white blood cells and platelets)
- the transparent, straw-colored plasma consists of water, ions, various plasma proteins, nutrients, waste products, respiratory gases, and hormones
- about 90% water.
- includes ions (blood electrolytes) which
maintaining osmotic balance and buffer the blood.
6
Q
what does proper functioning of muscles and nerves depend on?
A
Proper functioning of muscles and nerves depends on the concentrations of ions in the interstitial fluid, which reflects concentrations in the plasma.
7
Q
how does plasma help with transport?
A
Plasma carries a wide variety of substances in transit from one part of the body to another
1) nutrients
2) metabolic wastes
3) respiratory gases
4) hormones.
8
Q
what do plasma proteins do?
A
- buffer against pH changes.
- help maintain osmotic balance
- contribute to the blood’s viscosity.
- specific proteins transport otherwise-insoluble lipids in the blood.
- immunoglobulins (antibodies) help combat viruses and other foreign agents that invade the body.
- Fibrinogen helps plug leaks when blood vessels are injured.
9
Q
A
10
Q
what do red blood cells do?
A
1) red blood cells (erythrocytes)
- transport oxygen
- the most numerous blood cells.
11
Q
what do white blood cells do?
A
2) white blood cells
- function in defense
12
Q
what are platelets?
A
platelets are pieces of cells
- also called thrombocytes
- involved in clotting
13
Q
what are the types of white blood cells? (leucocytes)
A
-neutrophils
-eosinophils
-basophil
-monocyte
-lymphocyte
14
Q
what does oxygen transport depend on in the erythrocyte?
A
- oxygen transport depends on rapid diffusion of oxygen across the red cell’s plasma membranes
15
Q
what do erythrocytes look like?
A
these cells look like small biconcave disks, presenting a great surface area
16
Q
what does the lack of nuclei for a red blood cell allow for?
A
lack nuclei (leaves more space in the tiny cells for hemoglobin, the iron-containing protein that transports oxygen)
17
Q
how do erythrocytes generate ATP?
A
lack mitochondria and generate their ATP exclusively by anaerobic metabolism
18
Q
true or false, red blood cells have a mitochondria?
A
false, they dont
19
Q
how many oxygen molecules does a hemoglobin bind to?
A
Each hemoglobin molecule binds up to four molecules of O2
20
Q
what does hemoglobin bind to?
A
O2 and Nitric oxide
21
Q
what happens as red blood cells go through the capillary beds of lungs?
A
As red blood cells pass through the capillary beds of lungs oxygen diffuses into the erythrocytes and hemoglobin binds O2 and NO
22
Q
what happens in the systemic capillaries?
A
In the systemic capillaries, hemoglobin unloads oxygen and it then diffuses into body cells
23
Q
what does NO do?
A
NO relaxes the capillary walls helping delivery of O2 to the cells
24
Q
do we have more red or white blood cells?
A
more red
25
what type of structure is hemoglobin?
quaternary
26
how does NO make blood vessels dilate?
relaxes the smooth muscle cells in the blood vessel
27
what do white blood cells do most of the time?
White blood cells spend most of their time outside the circulatory system, patrolling through interstitial fluid and the lymphatic system, fighting pathogens
28
what are the types of lymphocytes?
-B cells
-T cells
29
what are platelets? where do they orginate from?
Platelets are fragments of cells
- they have no nuclei and originate as pinched-off cytoplasmic fragments of large cells in the bone marrow.
- function in blood clotting.
30
How do lymphocytes and erythrocytes form?
31
what are the two main classes of white blood cells?
-granulocytes
-agranulocytes
32
what are granulocytes?
includes Neutrophils, Eosinophils and Basophils
33
what are agranulocytes?
includes Lymphocytes and Monocytes
34
what's another word for white blood cell?
leukocytes
35
what's another word for red blood cell?
erythrocytes
36
true or false, all white blood cells are able to migrate out of blood vessels into surrounding tissue?
true
37
what is the difference between granulocytes and agranulocytes?
This classification depends on whether granules can be distinguished in their cytoplasm
38
what are neutrophils?
single multilobed nucleus. They are the commonest type of white blood cell. Neutrophils are born in the bone marrow. They circulate in the blood for 6-10 hours, and then enter the tissues. They are phagocytic and will destroy damaged tissue and bacteria. They are important in inflammatory reactions.
39
what is the most common white blood cell?
neutrophils
40
what are eosinophils?
two lobed nucleus. These cells have large granules - these stain bright red, or reddish-purple.They phagocytose antigen-antibody complexes. A high eosinophil blood count may indicate an allergic reaction.Eosinophils are also important in killing parasitic worms
41
what are basophils?
blue-staining granules and a bilobed nucleus. These cells are involved in immune responses to parasites and also play a role in allergic reactions.
42
what are lymphocytes?
have a small spherical nucleus and abundant dark staining condensed chromatin. There are 2 types. The B-cells develop into plasma cells which make antibodies, T-cells attack viruses, cancer cells, and transplants. Lymphocytes play a major role in the immune response
43
what are monocytes?
a large eccentrically placed nucleus, which is kidney bean shaped.They have abundant cytoplasm, and some fine pink/purple granules in cytoplasm. Monocytes in the circulation are precursors of tissue macrophages that are actively phagocytic. Monocytes circulate in the blood for 1-3 days, and then migrate into body tissues, where they transform into macrophages. They will phagocytose dead cells and bacteria. Monocytes are important in the inflammatory response.
44
how long do erythrocytes circulate for?
Erythrocytes usually circulate for only about 3 to 4 months and are then destroyed by phagocytic cells in the liver and spleen.
44
45
what happens to old cellular elements of blood after they are destroyed by phagocytic cells in the liver and spleen?
Enzymes digest the old cell’s macromolecules, and the monomers are recycled.
Many of the iron atoms derived from hemoglobin in old red blood cells are built into new hemoglobin molecules.
46
where do erythrocytes, leukocytes and platelets develop from?
all develop from a single population of cells, pluripotent stem cells, in the red marrow of bones, particularly the ribs, vertebrae, breastbone, and pelvis
47
what does pluripotent mean?
Pluripotent means that these cells have the potential to differentiate into any type of blood cells or cells that produce platelets.
48
how can we experimentally treat leukemia?
remove pluripotent stem cells from a patient, destroy the bone marrow, and restock it with noncancerous pluripotent cells.
49
what are the different types of erythrocyte production control?
- If the tissues do not receive enough oxygen, the kidney converts a plasma protein to a hormone called erythropoietin, which stimulates production of erythrocytes.
- If blood is delivering more oxygen than the tissues can use, the level of erythropoietin is reduced, and erythrocyte production slows
50
what are the steps of blood clotting?
The clotting process begins when the endothelium of a vessel is damaged and connective tissue in the wall is exposed to blood.
(1) Platelets adhere to collagen fibers and release a substance that makes nearby platelets sticky.
(2) The platelets form a plug.
(3) The seal is reinforced by a clot of fibrin when vessel damage is severe.
51
what is hemophilia?
Hemophilia is an inherited defect in any step of the clotting process
- characterized by excessive bleeding from even minor cuts and bruises
52
what prevents spontaneous clotting?
Anticlotting factors in the blood normally prevent spontaneous clotting
53
what are thrombus? who gets them?
Sometimes platelets clump and fibrin coagulates within a blood vessel, forming a clot called a thrombus, and blocking the flow of blood.
These potentially dangerous clots are more likely to form in individuals with cardiovascular disease
54
what is a heart attack?
heart attack is the death of cardiac muscle tissue resulting from prolonged blockage of one or more coronary arteries
55
what is a stroke?
A stroke is the death of nervous tissue in the brain
56
what is the link between thrombus, strokes and heart attacks?
Heart attacks and strokes frequently result from a thrombus that clogs a coronary artery or an artery in the brain
57
what's an embolus?
thrombus may originate at the site of blockage or it may develop elsewhere and be transported (now called an embolus) until it becomes lodged in an artery too narrow for it to pass
58
what's atherosclerosis?
growths called plaques develop in the inner wall of the arteries, narrowing their bore.
- the smooth muscle layer of an artery thickens abnormally and becomes infiltrated with fibrous connective tissue and lipids such as cholesterol
59
what is arteriosclerosis?
plaques also become hardened by calcium deposits, commonly known as hardening of the arteries.
60
true or false, Vessels that have been narrowed are more likely to trap an embolus and are common sites for thrombus formation
true
61
what is angina pectoris?
if a coronary artery is partially blocked, a person may feel occasional chest pains, a condition known as angina pectoris.
62
what is angina pectoris a sign of?
This is a signal that part of the heart is not receiving enough blood
63
what are foam cells?
Foam cells are a type of macrophage that localize to fatty deposits on blood vessel walls, where they ingest low-density lipoproteins and become laden with lipids, giving them a foamy appearance
64
what is hypertension
high blood pressure
65
what does hypertensions promote?
promotes atherosclerosis and increases the risk of heart disease and stroke
66
what does high blood pressure cause?
high blood pressure causes chronic damage to the endothelium that lines arteries, promoting plaque formation
67
what are non genetic factors that cause hypertension?
nongenetic factors include smoking, lack of exercise, a diet rich in animal fat, and abnormally high levels of cholesterol in the blood.
68
true or false, the tendency to develop hypertension and atherosclerosis is inherited
true, to a certain extent
69
what is the LDL HDL ratio?
- measure of an individual’s cardiovascular health or risk of arterial plaques can be gauged by the ratio
70
which is the bad cholesterol?
LDL
71
what is LDL
LDL (low density lipoprotein) is associated with depositing of cholesterol in arterial plaques.
72
what is plaque?
Plaque is made up of deposits of cholesterol and other substances in the artery
73
what is HDL?
(high density lipoprotein) may reduce cholesterol deposition
74
what does HDL do to reduce cholesterol deposition?
scavenges blood for LDL and brings it to liver to metabolize it
75
what is gas exchange?
Gas exchange (respiration) is the uptake of molecular oxygen (O2) from the environment and the discharge of carbon dioxide (CO2) to the environment.
- works together with the circulatory system
76
what are the four processes of respiration?
respiratory system:
-pulmonary ventilation
-external respiration
circulatory system:
-transport
-internal respiration
77
what is pulmonary ventilation?
movement of air into and out of lungs
78
what is external respiration?
exchange of O2 and CO2 between lungs and blood
79
what is transport?
Transport of O2 and CO2 in blood
80
what is internal respiration?
exchange of O2 and CO2 between systemic blood vessels and tissues
81
what are the respiratory surface?
lungs
82
how does CO2 and O2 cross the respiratory surface?
diffusion
83
what does diffusion require respiratory surfaces to be?
1) thin
2) have large areas
3) moist (necessary for gas phase diffusion)
84
where are the capillaries in the lungs?
Lungs have a dense net of capillaries just under the epithelium that forms the respiratory surface
85
what do lungs look like?
Lungs have a spongy texture and are honeycombed with a moist epithelium
86
how does air enter the body?
Air enters through the nostrils and is then filtered by hairs, warmed and humidified, and sampled for odors
- nasal cavity leads to the pharynx, and when the glottis is open, air enters the larynx
87
what is the wall of the larynx reinforced by?
wall of the larynx is reinforced by cartilage
88
what is the voice box?
- larynx is adapted as a voicebox in which vibrations of a pair of vocal cords produce sounds
89
how does talking work?
sounds are high-pitched when the cords are stretched tight and vibrate rapidly and low-pitched when the cords are less tense and vibrate slowly
90
true or false, the trachea is maintained by rings of cartilage
true
91
what does the trachea fork into?
forks into two bronchi
92
what do bronchus branch into?
each bronchus branches repeatedly into finer and finer tubes, called bronchioles.
93
how is the epithelium lining the major branches of the respiratory tree?
- is covered by cilia and a thin film of mucus.
- mucus traps dust, pollen, and other particulate contaminants, and the beating cilia move the mucus upward to the pharynx, where it is swallowed.
- the tiniest bronchioles dead-end as a cluster of air sacs called alveoli.
94
what does the alveolar wall consist of?
Single layer of squamous epithelium
Scattered cuboidal cells secrete surfactant and antimicrobial proteins
95
what's a surfactant?
Surfactant is body’s detergent-like lipid and protein complex that helps reduce surface tension of alveolar fluid and this prevents alveolar collapse
96
how does oxygen enter the body? how does carbon dioxide leave the body?
Oxygen dissolves in the moist film and rapidly diffuses across the epithelium into a web of capillaries that surrounds each alveolus
Carbon dioxide diffuses in the opposite direction.
97
in the systemic circuit, what is the link between cellular respiration and the systemic circuit?
-during cell respiration, we need O2 as a reactant so the capillaries give the tissue this
-the CO2 leaves as its a product of cellular respiration
98
how do humans ventilate?
negative pressure breathing
99
what are the lungs enclosed by?
double-walled sac (called the pleural sac)
100
what is the pleural sac?
The lungs are enclosed by a double-walled sac (called the pleural sac) with the inner layer of the sac adhering to the outside of the lungs and the outer layer adhering to the wall of the chest cavity.
101
what is between the two layers of the pleural sac? what does this allow for?
fluid
- A thin space filled with fluid separates the two layers.
- Because of surface tension, layers can slide smoothly past each other, but they cannot be pulled apart easily.
Surface tension couples movements of the lungs to movements of the rib cage
102
what happens during inhalation?
Contraction of the rib muscles expands the rib cage by pulling the ribs upward and the breastbone (sternum) outward.
- diaphragm contracts and descends like a piston. The diaphragm is a sheet of skeletal muscle that forms bottom wall of thoracic cavity
- most of the time it contracts involuntarily
- increases the lung volume, and air pressure within the alveoli becomes lower than atmospheric pressure.
- air rushes into the respiratory system.
103
what is the diaphragm?
diaphragm contracts and descends like a piston. The diaphragm is a sheet of skeletal muscle that forms bottom wall of thoracic cavity
104
what happens during exhalation?
- the rib muscles and diaphragm relax.
This reduces lung volume and increases air pressure within the alveoli.
This forces air up the breathing tubes and out through the nostrils.
- muscle actions described above are for shallow breathing, when at rest
During vigorous exercise, other muscles of the neck, back, and chest further increase ventilation volume by raising the rib cage even more.
105
what happens during exhalation during rigorous exercise?
During vigorous exercise, other muscles of the neck, back, and chest further increase ventilation volume by raising the rib cage even more.
106
what does surfactant allow for?
A substance called surfactant helps the alveoli to stay open for gas exchange. By reducing the surface tension of the fluid on the alveoli, the alveoli remain open even during exhalation.
107
why do premature babies struggle to breathe?
Because surfactant is made later in pregnancy, premature babies are lacking a sufficient quantity and this will lead to respiratory distress in the premature newborn
108
why does surfactant allow the alveoli to stay open during expiration?
owering surface tension at the air–liquid interface and thus preventing alveolar collapse at end-expiration
109
what is tidal volume?
The volume of air inhaled and exhaled with each breath
110
what is the maximum tidal volume called?
vital capacity
111
what is the average tidal volume for a human at rest
500 ml
112
why is there a residual volume in the alveoli after expiration?
some air remains in the lungs, the residual volume, because the alveoli do not completely collapse. needed to keep alveoli open. amount of air that remains after forced expiration
113
what is the inspiratory reserve volume?
amount of air that can be inspired forcibly beyond the tidal volume (2100–3200 ml)
114
what is the expiratory reserve volume?
amount of air that can be forcibly expelled from lungs (1000–1200 ml)
115
what are respiratory capacities?
Combinations of two or more respiratory volumes
116
what is the inspiratory volume?
sum of TV + IRV
117
what is Vital capacity?
sum of TV + IRV + ERV
118
what is total lung capacity?
sum of all lung volumes (TV + IRV+ ERV + RV)
119
what is dead space?
does not contribute to gas exchange
Consists of air that remains in passageways
~150 ml out of 500 ml TV
120
what is forced vital capacity?
amount of gas forcibly expelled after taking deep breath
121
what is forced expiratory volume?
amount of gas expelled during specific time interval of FVC
Healthy individuals can expel 80% of FVC in 1st second
122
what is minute ventilation?
: total amount of gas that flows into or out of respiratory tract in 1 minute
Normal at rest = ~ 6 L/min
Normal with exercise = up to 200 L/min
Only rough estimate of respiratory efficiency
123
what happens since the lungs do not completely empty and refill with each breath cycle
newly inhaled air is mixed with oxygen-depleted residual air.
- maximum oxygen concentration in the alveoli is considerably less than in the atmosphere.
- limits the effectiveness of gas exchange.
124
what controls the rate and depth of breath?
Control centers in the brain regulate the rate and depth of breathing
- most of the time autonomic mechanisms regulate our breathing
125
where are the breathing control centers located in the brain?
the medulla oblongata and the pons
126
what does the medulla do to control breathing?
the medulla’s center sets basic breathing rhythm, triggering contraction of the diaphragm and rib muscles
127
what does the pons do?
aids the medulla via its control center
128
what does the negative feedback inhibition mechanism in the lungs do?
negative-feedback mechanism via stretch receptors prevents our lungs from overexpanding by inhibiting the breathing center in the medulla
129
where do cues about the concentration of CO2 come from?
cues about CO2 concentration come from slight changes in the pH of the blood and cerebrospinal fluid bathing the brain
130
what does the medulla control center of the brain do?
monitors the CO2 level of the blood and regulates breathing activity appropriately
131
why does carbon dioxide lower the pH?
Carbon dioxide reacts with water to form carbonic acid, which lowers the pH
132
what happens when the medulla control center registers a slight drop in blood pH?
When the control center registers a slight drop in pH, it increases the depth and rate of breathing, and the excess CO2 is eliminated in exhaled air
133
what happens when we hold our breath?
-CO2 levels in blood rise
-CO2 combines with water to form carbonic acid
-carbonic acid dissociates to form HCO3- AND H+ (which makes blood more acidic)
-PH sensors detect change and send signal to the brain, forcing the person to breathe
134
true or false, oxygen concentration levels usually have a big effect on breathing
false
135
what happens at high altitudes? why does this process work?
- when the O2 level is severely depressed (at high altitudes) sensors in the aorta and carotid arteries in the neck send alarm signals to the breathing control centers, which respond by increasing breathing rate.
- Normally, a rise in CO2 concentration is a good indicator of a fall in O2 concentrations, because these are linked by the same process - cellular respiration.
136
what is hyperventilation?
increased depth and rate of breathing that exceeds body’s need to remove CO2
purges the blood of so much CO2 that the breathing center temporarily ceases to send impulses to the rib muscles and diaphragm
137
what can hyperventilation be caused by?
anxiety attacks
138
how can we stop hyperventilation?
Treatment: breathing into paper bag increases CO2 levels being inspired
139
control of breathing is only effective when it is matched to...
the circulatory system
140
what does gas diffusion depend on?
Diffusion depends on differences in partial pressure
141
what is partial pressure?
the contribution of a particular gas to the overall total
142
how do gasses diffuse?
A gas will always diffuse from a region of higher partial pressure to a region of lower partial pressure
143
what is her atmospheric pressure at sea level?
At sea level, the atmospheric pressure = 760 mm Hg
144
is there more O2 or CO2 in the air?
a lot more O2
145
what happens during gas exchange in the lungs?
Blood arriving at the lungs via the pulmonary arteries has a lower PO2 and a higher PCO2 than the air in the alveoli.
- As blood enters the alveolar capillaries, CO2 diffuses from blood to the air within the alveoli, and oxygen in the alveolar air dissolves in the fluid that coats the epithelium and diffuses across the surface into the blood.
By the time blood leaves the lungs in the pulmonary veins, its PO2 has been raised and its PCO2 has been lowered
146
what happens during gas exchange in the tissues?
-In the tissue capillaries, gradients of partial pressure favor the diffusion of oxygen out of the blood and carbon dioxide into the blood.
Cellular respiration removes oxygen from and adds carbon dioxide to the interstitial fluid by diffusion
-After the blood unloads oxygen and loads carbon dioxide, it is returned to the heart and pumped to the lungs again, where it exchanges gases with air in the alveoli.
147
what do respiratory pigments do?
Respiratory pigments transport gases and help buffer the blood
148
what would happen if we had no hemoglobin?
- a person exercising consumes almost 2 L of O2 per minute, but at normal body temperature and air pressure, only 4.5 mL of O2 can dissolve in a liter of blood in the lungs.
- If 80% of the dissolved O2 were delivered to the tissues (an unrealistically high percentage), the heart would need to pump 500 L of blood per minute - a ton every 2 minutes.
149
what is the respiratory pigment?
Hemoglobin, the respiratory pigment increases the amount of oxygen in the blood to about 200 mL of O2 per liter of blood.
150
what does hemoglobin consist of?
Hemoglobin consists of four subunits, each with a cofactor called a heme group that has an iron atom at its center, found in erythrocytes
151
why do we need respiratory pigments?
a person exercising consumes almost 2 L of O2 per minute, but at normal body temperature and air pressure, only 4.5 mL of O2 can dissolve in a liter of blood in the lungs. we need a certain amount of oxygen, but not enough can dissolve into our blood to cater to our needs
152
how much O2 can dissolve into blood at normal body temperature? what does this mean?
4.5 mL of O2 can dissolve in a liter of blood in the lungs. this means that the heart would have to pump an unrealistic amount of blood to oxygenate all the tissues
153
does hemoglobin bind reversibly or irreversibly to oxygen
reversibly, cause its needs to be able to unload it in all parts of the body
154
true or false, the subunits of the hemoglobin cooperate?
true
155
how do the subunits of the hemoglobin cooperate?
induces the remaining subunits to change their shape slightly such that their affinity for oxygen increases/decreases:
As O2 binds, Hb changes shape, increasing its affinity for O2 increases
As O2 is released, Hb shape change causes a decrease in affinity for O2
156
what happens as O2 saturation of hemoglobin increases?
P02 in blood also increases
157
true or false, the O2 saturation of hemoglobin is very big during exercise?
false. its very low (20%)
158
where is the evidence of cooperatively in the dissociation curve?
the steep slope
159
what is the link between pO2 and O2 saturation of hemoglobin?
even a slight change in PO2 of the tissues causes hemoglobin to load or unload a substantial amount of O2
corresponds to the range of partial pressures found in body tissues
160
what is the Bohr shift?
a drop in pH lowers the affinity of hemoglobin for O2, an effect called the Bohr shift.
161
what are the different factors that affect the hemoglobin/O2 bond?
-PH of the tissue
-temperature of the tissue
162
why does the PH of the blood affect the bond between the O2 and the hemoglobin?
because if the PH is lower, that means we have too much CO2, which means that we need more O2 in the blood, therefore the hemoglobin will release the O2
163
why does the temperature of the blood affect the bond between the O2 and the hemoglobin?
At higher temperatures the affinity of hemoglobin for oxygen is decreased. When a tissue is more metabolically active, its temperature will increase. Because the Hb has less affinity for oxygen at these higher temperatures, oxygen will be released to the metabolically active tissue
164
other than transporting oxygen, what else does hemoglobin do?
Hemoglobin also helps transport carbon dioxide and assists in buffering blood pH
165
what are the three different ways in which carbon dioxide is transported in the solution?
- 7% of the CO2 released by respiring cells is transported in solution.
- 23% binds to amino groups of hemoglobin (called carbaminohemoglobin)
- 70% is transported as bicarbonate ions.
166
what happens to CO2 made by respiring cells?
CO2 from respiring cells diffuses into the blood plasma and then into red blood cells, where some is converted to bicarbonate, assisted by the enzyme carbonic anhydrase
167
which enzyme converts CO2 to bicarbonate in the red blood cell?
carbonic anhydrase
168
what is the equilibrium between bicarbonate and CO2?
The reaction that is catalyzed:
H2O + CO2 = H+ + HCO3-
The reverse reaction is also catalyzed. Carbonic anhydrase solubilizes carbon dioxide gas so we can breathe it out.
169
what happens at the lungs with the bicarbonate equilibrium?
At the lungs, the equilibrium shifts in favor of conversion of bicarbonate to CO2
170
What is the relationship between partial pressure and oxygen saturation?
As the partial pressure of oxygen increases, the number of oxygen molecules bound by hemoglobin increases, thereby increasing the saturation of hemoglobin.
171
Explain the diagram with the transport/release of CO2 from the erythrocytes
