blood physiology Flashcards
(97 cards)
1
Q
cellular components of blood
A
- RBCs (erythrocytes)
- WBCs (leucocytes)
- platelets (thrombocytes)
2
Q
plasma is ___% water
A
98
3
Q
plasma contains what
A
water, ions, plasma proteins (albumin, globulin, fibrinogen), clotting factors
4
Q
serum
A
plasma without the clotting factors
5
Q
blood transports what
A
Oxygen, carbon dioxide, nutrients,
hormones, waste products
6
Q
blood functions
A
- transport
- homeostasis
- protection against infections
- blood clottings
7
Q
functions of RBCs
A
- Oxygen (O2) transport
- Carbon dioxide (CO2) transport
- Buffer
8
Q
gas diffusion
A
high pressure –> low pressure
9
Q
Gas diffuses between terminal _____ due to difference in partial pressure
A
bronchioles and alveoli
10
Q
The rate of gas diffusion depends on the
A
partial pressure of gases.
11
Q
how are oxygen and carbon dioxide transported in blood
A
can both be dissolved in blood, or bound to haemoglobin.
In addition, the majority of carbon
dioxide is transported in the form of bicarbonate
12
Q
Dissolved O2 concentration =
A
= (PO2) x (O2 solubility at body temperature)
13
Q
henry’s law
A
the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas
14
Q
Erythrocytes (red blood cells) contain lots of _____ molecules
A
haemoglobin
15
Q
Each haemoglobin molecule contains ___ subunits
A
4
16
Q
Each of the 4 subunits of hemoglobin is bound to a
A
heme molecule
17
Q
Each heme molecule (on each of the subunit of hemoglobin) binds to an
A
O2 molecule
18
Q
→ Each haemoglobin molecule can carry up to
A
4 molecules O2
19
Q
hemoglobin binding O2 summary
A
- Erythrocytes (red blood cells) contain lots of haemoglobin molecules
- Each haemoglobin molecule contains 4 subunits
- Each subunit is bound to a heme molecule
- Each heme molecule binds to an O2 molecule
→ Each haemoglobin molecule can carry up to 4 molecules O2
20
Q
More red blood cells = ____oxygen that can be transported
A
more
21
Q
Oxyhaemoglobin (Hb−O2) is formed when
A
O2 binds to haemoglobin
22
Q
Oxyhaemoglobin is what colour
A
bright red-coloured molecule and so Oxygenated blood is bright red
23
Q
Hb + O2 ↔ Hb−O2
reversible; where is oxygen loaded and unloaded
A
- Oxygen is loaded onto RBCs at the lungs (high concentration of O2)
- Oxygen is unloaded at the tissues (low concentration of O2)
24
Q
The affinity of haemoglobin to O2 ____ as more O2 is bound
A
increases
25
is the curve between PO2 and O2 saturation of Hb is linear
no– sigmoidal curve
26
When all four heme sites are occupied by O2, the haemoglobin is said to be
saturated
27
when one to three of the heme sites are occupied w O2 the hemoglobin is said to be
partially saturated
28
A haemoglobin saturation of 100 percent would mean
every single heme unit in all of the
erythrocytes of the body is bound to oxygen.
29
In a healthy individual with normal
haemoglobin levels, haemoglobin saturation generally ranges from
95 to 99 percent
30
gases will travel from an area of higher partial pressure, to an area of
lower partial pressure
31
the more oxygen binds to heme, the affinity
increases
32
as the partial pressure of oxygen increases, a ____ percentage of oxygen molecules are bound by heme
greater
33
at lower partial pressures of
oxygen, ____ oxygen molecules will be bound by heme
fewer
34
in the lungs, at higher partial pressures of oxygen, the PO2 can change without much change in the
O2 sat, or oxygen concentration
35
______ plays a major role in how much oxygen is bound to heme in the lungs, as well as how much the oxygen dissociates from heme at the body tissues
partial pressure of oxygen
36
Although we consider venous blood returning to the heart to be deoxygenated some oxygen is still bound to haemoglobin, what is this oxygen for
This is an oxygen reserve that can be accessed when the tissues suddenly demand more oxygen.
37
P_50
the PO2 at 50% Hb saturation
38
what does P_50 indicate
Indicates the general affinity of O2 for Hb
39
right shift: P_50 increases
Increases O2 unloading at a given PO2
40
4 primary conditions in which more oxygen needed to be offloaded into peripheral tissues
- temp increase
- PCO2 increase
- decrease pH (increase H+)
- increase in metabolite of RBCs; BPG (BPG is biproduct of glycolysis)
41
Carbon monoxide (CO) has _____ affinity for the oxygen binding sites on haemoglobin than oxygen does
greater
42
HbCO of 50%
[Hb] is normal but 50% is bound
to CO rather than O2
* carbon monoxide poisoning
43
Anaemia
only 50% haemoglobin concentration
44
Converting CO2 into
HCO3-
* Carbonic anhydrase reaction
* RBC involvement
* 70-90% of CO2
45
Carrying of CO2 by Hb
* Hb binding
* Related to O2 content
* 5-23% of CO2
46
CO2 dissolved in plasma
* CO2 solubility
* 5-7% of CO2
47
3 ways of CO2 transport
convert, carry and dissolve
- convert; into bicarb
- carry; by Hb
- dissolve; into plasma
48
Chloride shift
HCO3- diffuses into the plasma
and is replaced by Cl-
49
Carbonic anhydrase (CA) causes carbon dioxide and water to form
carbonic acid
50
Carbonic anhydrase (CA) causes carbon dioxide and water to form carbonic acid, which then dissociates into two ions:
H+ and bicarbonate
51
bicarb concentration higher in or out RBCS
Bicarb tends to build up in the red blood cells, so there’s a greater concentration inside, than in the surrounding blood plasma
52
At the pulmonary capillaries what happens to RBCs in terms of bicarb and chloride
Much of the bicarb in the plasma diffuses back into the red blood cells in exchange for chloride ions (reaction reversed)
Hydrogen ions and bicarb join to form carbonic acid, which is converted back into carbon dioxide and water by carbonic anhydrase. Carbon dioxide then diffuses out of the red blood cells and into the plasma, where it diffuses across the respiratory membrane into the alveoli to be exhaled.
53
Carbaminohaemoglobin is formed when
haemoglobin and CO2 bind
is easily reversible
54
Oxygenated blood has slightly
____ CO2 than deoxygenated
lower
55
CO2 -Hb dissociation curve more
_____ than the O2-Hb dissociation curve
linear
56
Blood CO2 levels are maintained
within very _____ parameters
narrow
40 – 45 mmHg
57
erythropoiesis
RBC production
58
erythropoiesis stimulated by
erythropoietin (EPO)
59
erythropoietin (EPO) produced by
kidney
60
erythropoietin (EPO) is produced in response to
hypoxia (low oxygen in the kidney tissue)
61
Hypoxia
- Reduced availability of O2 at tissues
- Under-oxygenation of organs, tissues and cells
- Impairs normal metabolism
- If severe, can lead to cellular death
62
Hypoxaemia
- Low concentration of O2 in arterial blood (PaO2)
63
4 main types of tissue hypoxia
1) Cytopathic
* Mitochondrial dysfunction inhibits effective utilisation of oxygen
* Septic shock
2) Anaemic
* Blood doesn’t have enough O2 carrying capacity
3) Stagnant
* Low cardiac output
* Low tissue perfusion
4) Hypoxemic
* Low PaO2 leading to low delivery of O2 to tissues
64
Coagulation
Process by which blood turns from a liquid to a gel; Forming blot clot
65
coagulation results in
haemostasis
* Begins almost instantly when endothelium of a blood vessel is damaged
* Stops blood loss
* Followed by repair process
66
Haemostasis
innate response for the body to stop bleeding
67
3 things that happen in haemostasis
1) vascular spasm
2) primary haemeostasis
3) secondary haemostasis
68
vascular spasm (first step of haemostasis)
- vasoconstriction of blood vessels
- damaged vessels constrict, reducing the amount of blood flow; helping reduce blood loss.
-Collagen fibres are exposed at the site of the injury; collagen promotes the adhesion of platelets to the site of the injury
69
primary haemostasis (second step of haemostasis)
* Platelets immediately
form a “plug” at site of injury
* Degranulate; they release granules that contain things like
- Serotonin; helps increase vasoconstriction
- ADP; attracts more platelets
- Thromboxane A2, helps platelet aggregation
* Positive feedback loop
70
secondary haemostasis (third step of haemostasis)
* Occurs simultaneously
* Proteins in blood plasma
(clotting factors) respond
in a complex “clotting cascade”
* Form fibrin strands from inactive fibrinogen
* Fibrin strands strengthen
platelet “plug”
71
Granulocytes
WBCs that contain granules
include
*neutrophils
*eosinophils
*basophils
72
Agranulocytes
WBCs that lack visible granules, include
* B lymphocytes
* T lymphocytes
* Natural killer cells
* Monocytes (macrophages)
73
Innate Immune Response
non-specific immune reactions
74
Chemotaxis
part of innate immune response: attracted by chemical substances released
75
Phagocytosis
part of innate immune response: engulf and digest
76
innate immune response activates adaptive immune system via
antigen presentation
77
The major white blood cell in the circulation is the
neutrophil
78
usually first cells to arrive at site of infection
neutrophil
79
neutrophil involved predominantly in
phagocytosis
80
Monocytes are found in the blood, and differentiate into _____ in the tissues
macrophages
81
Monocytes function
phagocytic cells
82
Dendritic cells functions
- phagocytic
- main function is activation of T cells
- engulf antigen material, process it, and present it on their cell surface to T cells
83
Eosinophils, basophils and mast cells are specialised to produce
inflammatory mediators
84
natural killer cells function
kill infected cells
involved in cell‐mediated, cytotoxic innate immunity
85
adaptive immune response
Specific – adaptive immune reactions
* Immunological “memory”
* Leads to enhanced response to future exposes to pathogen
* Slower - lag time between exposure and maximal responses
86
cells of the adaptive immune response
B cells: Make antibodies that bind to pathogens
T cells; Including:
CD4+
* “Helper” T cells
* Help coordinate immune response
* Differentiate into Th1, Th2, Th17 and Treg cells
CD8+
* Cytotoxic T cells
* Kill infected/tumour cells without damaging surrounding tissues
87
How many oxygen molecules can bind to one haemoglobin protein?
4
88
Why does the oxygen-haemoglobin dissociation curve have a sigmoidal shape?
As each oxygen molecule binds to haemoglobin, the affinity for the next oxygen molecule is increased
89
Which of the following factors shifts the oxygen-haemoglobin dissociation curve to the left?
A.
High temperature
B.
High concentration of CO2
C.
Increase in pH
D.
Decrease in pH
C.
Increase in pH
90
Which of the following factors will shift the oxygen-haemoglobin dissociation curve to the right?
A.
Decrease in pH
B.
Decrease in body temperature
C.
Decrease in 2,3 DPG
D.
Decrease in hydrogen ion concentration
Decrease in pH
91
Which of the following ions is bicarbonate exchanged for in a red blood cell?
Chloride
92
Which of the following statements is CORRECT when comparing the CO2-haemoglobin dissociation curve to the O2-haemoglobin dissociation curve?
The CO2-Hb dissociation curve is more linear
93
Which of the following statements is NOT true regarding carbon dioxide transport in the blood?
A.
There is more CO2 dissolved in the blood than O2
B.
The solubility of oxygen is greater than that of carbon dioxide
C.
Less carbon dioxide is bound to haemoglobin as compared to oxygen
D.
The majority of the carbon dioxide in the body is in the form of bicarbonate ions
B.
The solubility of oxygen is greater than that of carbon dioxide
94
What is the first response that takes place when a blood vessel is injured?
Vascular smooth muscle cells of the damaged vessels constrict, reducing the amount of blood flow through the area
95
Which of the following statements BEST describes "secondary haemostasis"?
The clotting cascade leads to the formation of fibrin strands around the platelet "plug", from inactive fibrinogen
96
Which of the following cells contributes towards adaptive immune responses
A.
Neutrophil
B.
CD4+ T cell
C.
Macrophage
D.
Eosinophil
CD4+ T cell
97
Which of the following cells identifies and removes foreign substances through phagocytosis?
A.
Basophil
B.
B cell
C.
Neutrophil
D.
Natural killer cell
C.
Neutrophil
