Blood Lectures Flashcards
1
Q
Where does blood move?
A
Through the plasma which is found in the capillaries of the circulatory system
2
Q
Why is blood a highly dynamic tissue?
A
It is constantly moving a making exchanges
3
Q
What are the three functions of blood?
A
- Transport
- Acid-Base Balance
- Protection
4
Q
What does blood transport?
A
-Nutrients
-Respiratory gasses
-Wastes
-Hormones
-Temperature regulation
5
Q
How does blood help with temperature regulation?
A
Metabolic reactions generate heat, as blood moves out to our extremeties, it can cool the body
6
Q
What makes up blood?
A
Plasma - 55 %
Buffy Layer - WBCs and platelets
Red Blood Cells - 45%
7
Q
True or false: Blood is made up of both ECF and ICF?
A
True
8
Q
What component of blood is the extracellular fluid?
A
Plasma
9
Q
What component of blood is the intracellular fluid?
A
Fluid inside the blood cells
10
Q
Define Normovolemia
A
Normal blood volume
11
Q
Define Hypovolemia
A
Lower blood volume
12
Q
Define Hypervolemia
A
Higher blood volume
13
Q
What is the hematocrit?
A
The percentage of blood volume occupied by red blood cells
14
Q
How is hematocrit calculated?
A
Height of the red blood cell column/ height of the whole blood column and then times 100%
15
Q
What is a normal hematocrit?
A
45%
16
Q
What components make up the plasma?
A
-Over 90% water
-Contains ions, high in sodium chloride
-Contains nutrients, respiratory gasses and wastes (glucose, amino acids, lipids, O2, Urea, Lactic acid, CO2)
-Contains proteins(colloids)
17
Q
What is the difference between the ISF and plasma?
A
Plasma contains proteins
18
Q
What are the different ways to separate proteins from plasma?
A
- Differential precipitation by salts
- Sedimentation in ultracentrifuge
- Immunological characteristics
- Electrophorectic Mobility (most common)
19
Q
What is electrophoresis?
A
Separating molecules based on movement of charged particles along a voltage gradient
20
Q
What influences the rate of migration in electrophoresis?
A
- The number and distribution of charge (more charged moves closer to positive pole )
- The molecular weight of each protein (heavy protein migrates slower)
21
Q
What does the size of the bands on the paper indicate?
A
Larger band = more of that protein
22
Q
What is serum and why is it used in electrophoresis?
A
Serum is plasma with no fibrinogen(clotting factor). It is used for electrophoresis because this way the sample won’t clot when trying to run it on the gel matrix
23
Q
Where do most plasma proteins originate?
A
Liver
24
Q
What plasma proteins are produced at the liver?
A
- Albumin
- Fibrinogen
- Globulins (alpha-1, alpha-2, beta)
25
Where are gamma globulins (Y) produced?
The lymphoid tissue
26
What happens when the liver is diseased?
Plasma proteins decrease
27
How will the electrophoretic pattern change in renal disease?
The albumin peak will be much smaller because the kidney tubules will become too permeable and the smallest protein will be lost into the urine(albumin)
28
How will the electrophoretic pattern change in a bacterial infection?
Gamma globulin peak will increase because these are the antibodies
29
What is the smallest plasma protein?
AlbuminW
30
How are globulins shaped?
Globulins have a variety of shapes and sizes
31
What are transcapillary dynamics?
Plasma proteins determine the distribution of fluid between the plasma and the ISF compartments
32
What separate the ISF and the plasma ?
The capillary wall
33
What is the capillary wall permeable/immpermeable to ?
Permeable: H2O and ions
Impermeable : Proteins
34
what is the water distribution between ISF and plasma?
15% (ISF) and 5% (plasma)
3:1 ratio
35
What is the ECF?
ISF and Plasma
36
What is the osmolarity of the ECF?
300 mOsm
37
Why can plasma proteins exert an osmotic effect ?
Because they are non-diffusable molecules and cannot cross the capillary wall to equally distribute themselves
38
What is colloidal osmotic pressure(COP)?
Osmotic pressure resulting from proteins in the plasma that cannot cross the capillary wall
39
How much pressure do the proteins exert?
25 mmHg
40
What does the COP do?
Water from the ISF wants to flow into the plasma
41
What happens if COP increase/decreases?
COP increase: more water will flow into the plasma
COP decrease: more water will flow into the ISF
42
What are the two types of transport across the capillary wall?
Filtration (bulk flow)
Osmotic flow
43
What is bulk flow/filtration?
Water flowing into the ISF. Plasma in the blood vessel is under pressure which tend to "push out" fluid from inside the capillaries into the ISF
44
What is osmotic flow?
Plasma protein create COP which tend to "pull in" or retain fluid inside the capillaries
45
What are filtration and osmotic flow known as?
Starling Forces
46
Are starling forces responsible from exchange of nutrients, gasses and wastes across the capillary?
No, these molecules are small enough that they do not cause a pressure difference and therefore are transported via diffusion
47
How does blood flow through the circulatory system?
1. Oxygenated blood pumps through arteries from the heart
2. Exchanges occur at the capillary bed
3. Blood that lacks nutrients and has CO2 goes back to the heart via the venules
48
Why do no exchanges occur in the arteries?
Arteries are associated with a basement membrane and muscles that make exchanges too hard
49
Why do exchanges occur at the capillay beds?
Capillary beds are only made up of a single layer of endothelial cells
50
What does BP 120 over 80 mean?
Everytime the heart pumps you have 120 mmHg of pressure in the circulatory system. By the time you reach the capillaries that pressure will have decreased significantly due to friction with the walls
51
What is BP right before the capillary beds?
35 mm Hg
52
What is the BP right after the capillary beds?
15 mm Hg
53
What is the net filtration pressure ?
Hydrostatic pressure pushing out the fluid into the ISF
54
What balances the net filtration presure to make sure the volumes remain constant between the ISF and the plasma?
The net absorption pressure
55
Ture or False: Exchanges of fluid occurs across the entire capillary bed?
True
56
What happens to the fluid pushed out of the capillaries into the ISF?
90% of the fluind is reabsorbed into the capillaries
10% of the fluid is moved from the ISF and carried away by the lymphatic vessels
57
What is the lymphatic system?
A network of blind ended tubules that coalesce to form lymphatic vessels, whoch form lymphatic ducts whith drain into the large veins in the chest. The lymphatic system is found everywhere where we have capillaries
58
Why are lymphatic vessels so permeable?
Similar to the capillary beds, lymphatic vessels are made up of a single layer o f endothelial cells.
59
What are lymphatic vessels permeable to ?
Highly permeable to all ISF constituents incluidng proteins
60
How much blood is in our body?
5L
61
Do capillaries leak proteins into the ISF?
Normally, they do not how ever if they do then proteins can be absorbed by lymphatic vessels
62
Which proteins contribute the most to COP?
Osmotic pressure depens on the number of osmotically active particles
It is directly proportional to its concentration in the plasma (higher concentration more COP)
It is inversely proportional to molecular weight (lower weight proteins cause more COP)
63
What proteins exert the most COP?
Albumin because it has the smallest molecular weight
64
Factors that effect transcapillary dynamics?
1. Hydrostatic pressure
2. COP
3. Capillary permeability
4. Lymphatic drainage
65
How can hydrostatic pressure effect transcapillary dynamics?
High BP will increase hydrostatic pressure causing more fluid to want to move out of the capillaries (can cause edema)
66
How can capillary permeability effect transcapillary dynamics?
Increased permeabiliy can caused us to lose proteins to the ISF which wil change fluid dynamics (more fluid going out into the ISF)
67
What is edema?
Accumulation of excess fluid in the interstitial spaces (not enough in the plasma)
68
How can decreased plasma protein cause edema?
There will be a lower COP, which will cause less fluid to be pulled into the plasma
69
How can increase capillary permeability cause edema?
Lower COP (proteins leaking out into the ISF)
70
How can obstruction of lymphatic drainage cause edema?
This can cause a backup in the lymphatic vessels leading to more fluid in the ISF
71
What can cause decreased COP?
1. Renal disease (losing protein to urine)
2. Liver disease (not producing the proteins)
3. Pregnancy (fetus compresses veins, less venous return)
72
How can we treat edema?
Diuretics- to increase fluid loss via urination
73
What is Kwashiorkor?
Severe protein malnutrition
74
What is oncotic pressure?
If proteins leak out of the capillary walls into the ISD they can exert oncotic pressure. Which will lead to more fluid wanting to be pulled out into the ISF
75
Who is at risk of reduced lymphatic drainage?
Women who had breast cancer and whose lymph nodes were removed, can lead to edema because the 10% that is supposed to be drained via the lymphatic system won't be drained
76
What is elephantiasis?
Blockage of lymphatic drainage resulting from parasite infection (filaria nematode)
77
What three roles do plasma proteins play in our body?
1. Help determine the distribution of fluid between the plasma and the ISF by starling forces
2. Contribute to the viscosity of plasma (viscosity contributes to blood pressure)
3. Contribute to the buffering power of plasma (help maintain a pH of 7.4)
78
What do fibrinogen and some glubins do ?
Essential for clotting
79
What do Y-globulins do ?
Provide resistance to infection
80
What does albumin do ?
Act as carriers for lipid, minerals and hormones
81
Where do all blood cells come from?
A pluripotent hematopoietic stem cell in the bone marrow
82
What type of blood cells exist?
-Red blood cells
-Platelets
-White blood cells
83
What is the life span of each blood cell ?
RBC: 120 days
Platelets: 7-8 days
White blood cells: hours-years
84
Rank the blood cells from smallest to largest?
Smallest: Platelets
Medium: RBCs
Largest: White blood cells
85
What is hematopoiesis?
Blood cell production
86
What is erythropoiesis?
Production of red blood cells
87
What is Thromobopoiesis?
Production of platelets
88
What is leukopoiesis?
Production of white blood cells
89
What does the pluripotential stem cell do?
1. Self-replicates: to replenish the stem cell population(division)
2. Commits to becoming one of the three blood cells (differentiation_
90
What does an inducer do to the pluripotential stem cell?
Induces it to differentiate into a blood cell
91
What does a stimulant do to commited stem cells?
Stimulates them to produce their specific blood cell
92
What are cytokines?
Substances/hormone which are release by one cell and affect the growth, development, and activity of another cell
93
What is a hematopoietic growth factor (HGF)?
A cytokine that influences the proliferation and differentiation of blood cell precursors
94
Where does hematopoiesis occur?
3-4 weeks: yolk sac
After 3 months the fetus will continue production in the liver and spleen.
After birth production will occur in the bone marrow
95
In what bones do we produce blood cells?
Throughout life we produce blood cells in the bone marrow of the axial skeleton
Up until 30 we also produce blood cells in the long bones
96
Where does hematopoiesis occur in long bones?
In the proximal ends of the long bones (epiphysis)
97
What is the function of RBCs?
Facilitate transpor of respiratory gases (delivers oxygen to all the cells of the body via circulatory system)
98
What is the shape of the RBC?
Biconcave disk (thinner in the middle then at the edges)
99
Why do RBCs have this shape(protein)?
Spectrin, a fibrous protein, forms a flexible network linked to the cell membrane
100
What are the advantages of the RBC biconcave shape?
-Maximizes surface area and minimizes diffusion distance (increase CO2 and O2 diffusion efficiency)
-Higher degree of flexibility (allows RBCs to squeeze through the narrow capillaries)
101
What is a CBC?
Complete blood count (ie. how many RBCs)
102
Terms that define cell size?
Normocytic - normal size
Microcytic - smaller size
Macrocytic - bigger size
103
Terms that define cell shape?
Sickle cell
Spherocyte
104
True/False: Men have more RBCs than women?
True
105
what is rate of production and destruction?
Rate of production = rate of destruction. Every second your body makes 2 million new RBCs and destroys 2 million
106
What are RBCs made up of?
-Water
-Lipids, proteins, ions
- 33% Hemoglobin
107
What don't RBCs contain?
-NO organelles (mitochondria , ER, nucleus)
108
How do RBCs generate energy?
RBCs generate enrgy anaerobically with glycolytic enzymes (glucose)
109
What is the role of carbonic anhydrase in RBCs?
Converts CO2 to bicarbonate which is easier to transport
110
How many oxygen molecules can each hemoglobin bind?
Four
111
What is oxyhemoglobin vs deoxyhemoglobin?
Oxyhemoglobin: When hemoglobin is bound to oxygen
Deoxyhemoglobin: When hemoglobin is not bound to oxygen
112
What is the hemoglobin structure?
Made up of four chains(globin portion):
- 2 alpha chains
-2 beta chains
Associated with each chain is a heme group
Each heme group is then associated with a ferrous iron
113
What protein has a similar MW to hemoglobin?
Albumin
114
when the heme is saturated with O2 in the lungs what colour do it become?
Bright Red
115
When the heme is dissociated from the O2 in the tissues what colour does it become?
Dark Red
116
What is the point of hemoglobin?
Increases the solubility of oxygen in blood, so more oxygen can be transported
117
What are the three functions of hemoglobin?
1. transport of oxygen
2. Transport of CO2
3. Acts as a buffer to maintain pH of blood
118
Why are hemoglobins in the RBCs and not just in the plasma?
-Plasma viscosity would increase if Hb were dissolved in it
-Plasma COP would increase
- Hb would be lost through the kidney because its the same size as albumin
119
Do men have more Hb then women?
Yes, because they also have more RBCs
120
What affects the binding of O2 to Hb?
1. Temperature
2. Ionic composition
3. pH
4. pCO2(how much CO2 is present)
5. Intracellular enzyme contraction
121
How are RBCs produced?
Pluripotent stem cells commits to the myeloid stem cell then division occurs (nucleus) before RBCs join the circulation they will lose their nucleus and other organelles
1. Decrease in size
2. Loss of nucleus and organelles
3. Accumulation of Hb
122
How long does RBC production take?
3-5 days
123
What is erythropoietin ?
A cytokine that acts on myeloid stem cells to proliferate in RBCs
124
What is a reticulocyte?
Newly produced RBCs still have part of their ER (these only last 24 hrs)
125
Reticulocyte index?
Reflects the amount of effective erythropoises in the bone marrow
126
What determines the number of RBCs a person has?
1. O2 requirements
2. O2 availability
127
Who needs more RBCS?
-If i start exercising more I will have increase O2 requirements (more RBCS)
-If I am at a higher altitude there is less oxygen and I will need more O2 (more RBCs)
128
Where is erythropoietin(EPO) produced?
Kidney
129
What is hypoxia and what causes it ?
Not getting enough oxygen to the tissues
Causes:
-Decreased RBC count
-Decreased O2 availability
-Increase tissue demand for O2
130
What causes erythropoietin to be released?
Hypoxia
131
How is erythropoiesis regulated?
1. Blood circulates and is filtered through the kidneys, if the kidneys sense hypoxia they will release EPO.
2. The EPO will travel in the plasma and stimulate the bone marrow to produce more RBCs
3. This will increase oxygen in the plasma
4. Kidney will sense the increase in oxygen an will decrease its release of erythropoietin
132
What is erythropoiesis regulation an example of?
Negative feedback
133
What is negative feedback?
The thing that stimulated it also turns it off (oxygen)
134
How does a severe hemorhage affect RBC content?
1. Severe blood loss = loss of RBCs
2. Less Hb available for O2 transport
3. Reduced supply of O2 to kidneys (hypoxia)
4. Increase production of EPO
5. Increased production of erythrocytes
6. More Hb in blood for O2 transport
135
2 effects of EPO?
1. Committed stem cell will divide more into RBCs
2. Maturation of RBCs will occur much faster
136
How does testosterone effect erythropoietin ?
-Increases the release of erythropoietin
-Increases the sensitivity of RBC precursors to erythropoietin(don't need as much to stimulate RBC production)
137
How does estrogen effect erythropoietin?
-Decreases the release of EPO
-Decreases the sensitivity of RBC precursors to EPO
138
How do RBCs last for 120 days?
Due to the glycolytic enzymes that provide them with energy
139
Do RBCs have anyway to prolong their lives?
NO
140
How are old RBCs removed from the circulation?
As RBCs travel through the capillaries they get damaged and can't repair themselves, so macrophages eat them
141
Where do RBCs get eaten by macrophages?
In the liver and spleen
142
What happens to the RBC once it is digested in the phagocyte?
The phagocyte will release its contents, so that they can be reused by other cells
143
What is the RBC digested into (what components)?
-Hemoglobin
-Iron
-Globin(4 chains)
144
How is the globin recylced?
The globin is recycled into a pool of amino acids which can then be reused to make proteins
145
What happens to iron when it is released from the macrophage?
The iron is toxic if free in the body, so transferrin will bind to it and stores it in the liver, spleen and gut in the protein ferritin. When the body need Fe the ferritin will release it
146
What happens to the Hemoglobin after phagocytosis?
Most of it is sent to waste. The heme part of the hemoglobin is broken down into the pigment, bilirubin, this is what makes plasma yellow. The pigment gets processed in the liver into other pigments and is excreted in the feces
147
What happens if plasma has too much bilirubin?
Your plasma will be much more yellow and because you have capillaries everywhere the skin and eyes will appear yellow (jaundice)
148
Why is neonatal jaundice so common?
When the umbilical cord is cut the babies have an excess of RBCs and undergo a lot of hemolysis. This will breakdown a lot of heme into bilirubin
149
Causes of jaundice?
1. Excess hemolysis
2. Liver damage (bilirubin will back up through the blood, can't go through the intestinal tract)
3. Bile Duct Obstruction (if the bile duct is blocked (gallstone/tumour) bilirubin will back up into blood)
150
Normal dynamic for RBCs
Production = Destruction
151
What is polycythemia?
Producing more RBCs than you are destroying
152
What is anemia?
Prodcuing less RBCs than you are destroying (decrease in O2 carrying capacity of blood)
153
How to know if someone has polycythemia/anemia?
1. Number of RBCs(CBC)
2. Amount of Hb
3. Hematocrit
154
Describe the hematocrit of someone with polycythemia
They will have lower plasma volume and higher RBC volume
155
What would the hematocrit of a dehydrated person look like?
Very similar to that of someone with polycythemia
156
Describe the hematocrit of someone with anemia
They will have higher plasma volume and lower RBC volume
157
Can fluid retention cause the same hematocrit as anemia?
Yes
158
Can we rely on hematocrit to decide wether someone has polycythemia or anemia?
NO
159
What is the difference between relative polycythemia and absolute polycythemia?
Relative(not rela polycythemia):
- Caused by a decrease in plasma volume(ex. dehydration)
Absolute(REAL polycythemia)
-You really do have more RBCs than you should have and it could be physiological or pathological
160
What is physiological polycythemia?
Secondary effect that occurs due to higher need of O2 or lower O2 availability
-your body is working as it should but is just producing excess RBCs
161
What can cause physiological polycythemia?
- High altitude
-Increased physical activity
-Chronic lung disease
-Heavy smoking
162
What is pathological polycythemia?
Primary effect that occurs due to tumors of cells producing EPO or unregulated RBC production by bone marrow
- Your body is not working as it should
163
Why is polycythemia bad?
- Increases blood viscosity, thicker blood moves slower and increase risk of clots
164
Classifications of anemia?
Size: Microcytic, Normocytic, Macrocytic
Color: Normochromic, Hypochromic (less Hb = paler), Hyperchromic (too much Hb =darker)
165
How does diminished production cause anemia?
- Abnormality at the site of production
-Inadequate stimulus
-Inadequate raw materials
166
What type of anemia results from abnormality at the site of production and what is the cause and classification?
Aplastic (Hypoplastic) Anemia
Cause:
-Unknown
-Exposure to radiation (damages he bone marrow)
-Chemicals/drugs(damages he bone marrow)
Classification:
Normocytic, Normochromic (there is just a decrease in production)
167
What type of anemia results from inadequate stimulus and what is the cause and classification?
Stimulation failure anemia
Cause:
-Renal disease (less EPO production)
Classification:
-Normocytic, Normochromic (just not producing enough cells)
168
What type of anemia results from diminished production and what is the cause and classification?
Iron deficieny Anemia (most common)
Cause:
- Increased requirement for Fe (infancy, adolescence, pregnancy)
- Inadequate supply of Fe (dietary deficiency, failure to absorb, loss of Fe in hemorrhage)
Classification:
Microcytic, Hypchromic
(Cells won't make Hb and cells won't be as full)
169
How is iron stored in the body?
65% in hemoglobin
30% stored in ferritin
5% myoglobin
1% enzymes
170
How much iron do Males/Females absorb a day?
Males: 1 mg
Females: 2 mg
170
How much iron do we need a day ?
15-20 mg
171
How much iron does normal eryhtropoisis require?
25 mg Fe/day
172
Where do we get 25 mg of Iron per day?
Normal RBC destruction releases 25 mg/day but 1mg of that iron is lost to urine/feces so we must get it in our diet
173
Why do females require more iron?
Due to menstruation
174
What are the three causes of anemia?
-Diminished production
-Ineffective maturation
-Increase RBC destruction/ reduced RBC survival
175
What type of anemia does ineffective maturation cause and what causes it and what is its classification?
Maturation Failure Anemia
Causes:
-Deficiencies of vitamin B12 and folic acid (required for DNA synthesis)
Classification:
Macrocytic, Normochromic
(cells DNA stops dividing but RNA keeps dividing and filling up the cytoplasm)
176
Where is Vitamin B12 found?
Only in animal products
177
Where is folic acid found?
Leafy greens
178
How can someone have a failure to absorb vitamin B12?
-in order to absorb vitamin B12 the body requires a cofactor, intrinsic factor. If you lack an intrinsic factor in the stomach the B12 is going to be destroyed by the stomach. If you have the intrinsic factor the B12 will couple with it and will be carried through the GI tract to the illeum to be absorbed
179
What type of anemia does increased RBC destruction/Reduced RBC survival\ cause and what causes it and what is its classification?
Hemolytic Anemia (typically accompanied by jaundice)
Causes:
-Congenital
-Acquired (toxins, drugs, antibodies)
- Abnormal RBC membrane structure
(Spherocytosis: less flexible, more fragile = cleared out of the system more)
-Abnormal Enzyme Systems
(lack glycolytic enzymes thus won't last 120 days)
-Abnormal Hb structure
(sickle cell disease) (abnormal structure is broken down more frequently)
180
What is a hematoma?
Accumulation of blood in tissues
181
Hemostasis?
Arrest of bleeding following vascular injury
182
What is the primary Hemostasis?
Begins within seconds of the injury and only lasts minutes
1. Vascular response
2. Platelet response
183
What does primary hemostasis produce?
A platelet plug (can be enough for very small bleeds but from larger bleeds we need secondary hemostasis)
184
What is secondary hemostasis?
Clot formation
The production of a blood clot, long lasting stable structure
185
Steps of Hemostasis?
1. vascular injury : endothelial cells are damaged and blood is leaking
2. Vasoconstriction: Blood vessels contract so there is less blood flow to the site of injury
3. Platelet Plug Formation: Platelets aggregate at the site of injury and create a temporary plug
4. Blood Clot formation
186
What is the vascular response of primary hemostasis?
It is the vasoconstriction of blood vessels to lessen blood loss
-Smooth muscle cells contract, if the vessel is small enough the endothelial cells can stick together
187
Another name for the platelet plug?
White Thrombus
188
Describe the platelets structure.
-No nucleus
-Contains granules that can be secreted for vasoconstriction, platelet aggregation, clotting and growth
- life span 7-10 days
189
Where are platelets produced?
Bone marrow they are a blood cell
190
How does a stem cell become a platelet?
-Myeloid lineage
-Then becomes a megakaryocyte which breaks off into fragments (platelets)
191
What is thrombopoietin?
The cytokine for the production of platelets that acts on the committed cell
192
What is the role of vasodilators like NO and Prostacylcin in blood vessels?
Prevent RBCs, platelets and plasma proteins from sticking to the wall of the endothelium because this could cause an uneeded clot to form and obstructs blood flow.
193
How does platelet plug formation occur?
1. Vasvular injury occurs which exposes collagen. The collagen is sticky and causes platelets to bind to it.
2. The binding of platelets to the collagen causes them to release their granules and attract more platelets
3. Platelets secrete von Willebrand Factor, Thromboxane A2, ADP, Serotonin and PF3
194
What is the role of von Willebrand Factor?
It connects the platelets to the collagen
195
What is the role of ADP and Serotonin?
They are both vasoconstrictors
196
What does PF3 do?
Forms the platelet plug and leads to the coagulation cascade
197
What is the coagulation pathway?
This is the pathway that results in the formation of a blood clot, it is stimulated by the platelet factors
198
Platelet Functions
1. Release vasoconstricting agents/cytokines
2. Form platlet Plug
3. Release clotting factors
4. Participate in clot retraction
5. Promote maintenance of endothelial integrity
199
What is petechia?
A disease caused by a lack of platelets that causes red/purple spots due to bleeding into the skin
200
Abnormal primary hemostatic response?
Leads to prolonged bleeding
Causes:
- Failure of blood vessels to constrict
-Platelet deficiencies
201
What does thromboxane A2 do in platelet plug formation?
Helps platelets adhere to each other by making there membranes sticky
202
What does Aspirin do ?
Inhibits synthesis and release of Thromboxane A2 to prevent clot formation
203
Another name for a blood clot?
Red Thrombus
204
Are RBCs needed in clot formation?
No, clot formation only requires the plasma
205
How do fibrinogen and thrombin form the blood clot?
Fibrinogen is broken down into fibrin in the presence of thrombin which creates a mesh network that form the blood clot
206
What protein is critical for clot formation?
Thrombin
207
What do we need to have in order to produce thrombin?
-Ca 2+
-Prothrombin
-Prothrombinase
208
What are the two ways to get thrombin?
1. Intrinsic Pathway
2. Extrinsic Pathway
209
What are the differences between the Intrinsic and Extrinsic pathways?
Intrinsic:
-Everything needed to activate the pathway can be found in the vascular system
-Take 3-6 minutes
Extrinsic:
-Requires elements from outside the vascular system
-Take 15 -25 seconds
210
is the extrinsic pathway so fast?
As soon as the plug is formed the cell no longer as access to the factors found outside the vascular system
211
Why is the extrinsic pathway so important?
It has a positive feedback effect on the intrinsic pathway to produce even more thrombin
212
Factors required for coagulation
1. Ca 2+
2. Phospholipid
3. Protein Plasma Factors
213
Congenital clotting factor deficiencies?
-Present at the time of birth
-Single-factor hereditary deficiencies
-Ex. Hemophilia (not enough factor 8)
214
Acquired clotting factor deficiencies?
-Acquired during lifetime
-Multi-factor deficiencies
-Liver disease, vitamin K difciencies (most plasma factors are produced in liver and vitamin K is a recquired co-factor)
215
How does clot retraction occur/ what molecule does it?
Thrombosthenin, released by platelets, causes the clots to contract and shrink so that is becomes more solid (increases strength)
-Fluid forced out of the clot
-Draws the tissues together to promote wound healing
216
What keeps the clot in check?
1.Inhibitors of platlet adhesion
2. Anticoagulants : chemicals that block one or more of the reactions of the coagulation scheme
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What is clot lysis?
Removal of the clot after the wound is healed
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How does clot lysis occur?
1. Plasminogen breaks down into plasmin with the help of a plasminogen activator
2. Plasmin breaks down the fibrin network into fibrin fragments
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Name an inhibitor of platelet adhesion?
Aspirin (prevents thromboxane A2 from making platelets sticky)
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What is an anticoagulant and name two examples?
Anticoagulant: Interferes with clot formation
ex. Coumarin - block synthesis of different factors
Heparin- promotes inhibition of thrombin activation
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What is a thrombolytic drug and an example?
A drug that promotes clot lysis
Ex. Streptokinase and Tissue plaminogen Activator both break up the clot to restore blood flow
