Djdj Flashcards
1
Q
What are the main functions of blood?
A
1) Transportations of water, dissolved gases, nutrients, hormones, and metabolic wastes (nitrogen compounds, such as ammonia, urea, uric acid)
2) pH regulation and electrolyte balance
3) Prevention of fluid loss at inury site.
4) Defence against toxins and pathogens - immune system.
5) Stabilisation of body temperature.
2
Q
Whats an electrolyte?
A
electrolyte = positively / negatively charged ions
3
Q
What is our blood temperature?
A
37 - 37.6 degrees celcius
4
Q
blood vs water?
A
5 tiems more viscous than water.
5
Q
pH of blood?
A
Slightly alkaline (pH ≈ 7.38 - 7.42)
6
Q
How much body weight does blood make up?
A
Healthy adults: ≈ 7 to 8 % of body weight
7
Q
what is blood made up of?
A
46-63% plasma and 37-54% formed elements.
8
Q
what makes up plasma?
A
water - 92%
plasma proteins - 7%
regulatory proteins - <1%
other solutes - 1%
9
Q
what is water made up of and where is it produced?
A
fluid
absorbed by intestinal tract or produced by metabolism.
10
Q
what is the major function of water/fluid?
A
transport medium
11
Q
what is the 7% of plasma proteins made up of?
A
albumin - 54-60%
globulins - 35-38%
fibrinogen - 4-7%
12
Q
what are the <1% regulatory protein made up of?
A
hormones and enzymes.
13
Q
what are the 1 percent of other solutes in the plasma made up of?
A
nutrients, gases, and wastes.
14
Q
where is albumin produced?
A
liver
15
Q
where is globulins produced?
A
alpha globulins - liver
beta globulins - liver
gamma globulins (immunoglobulins) - plasma cells.
16
Q
where is fibrinogen produced?
A
liver
17
Q
where are hormones and enzymes produced?
A
various sourcesn
18
Q
where are the 1 percent “other solutes” produced?
A
absorbed by intestinal tract and exchanged in respiratory system or produced by cells.
19
Q
major function of albumin?
A
maintain osmotic concentration, transport lipid molecules,
20
Q
major functions of alpha globulins?
A
transport, maintain osmotic concentration
21
Q
major function of beta globulins?
A
transport, maintain osmotic concentration
22
Q
major function of gamma globulins?
A
immune responses
23
Q
major function of fibrinogen?
A
blood clotting in hemostasis
24
Q
major function of hormones and enzymes?
A
regulate various body functions
25
major functions of nutrients, gases, and wastes?
numerous and varied
26
what are formed elements composed of?
erythrocytes (99%)
leukocytes <1%
platelets <1%
27
what are the <1% leukocytes made up of?
granular leukocytes, neutrophils, eosinopils and basophils
and agranular leukocytes, lymphocytes and monocytes
28
where are platelets produced?
megakaryocytes and red bone marrow.
29
erythrocytes major function?
transport gases, especially o2 andf co2
30
major function of granular leukocytes and neutrophils, and eosinophils and basophils?
non specific immunity
31
major function of agranular leukocytes, lymphocytes, and monocytes?
lymphocytes: specific immunity
monocytes: non specific immunity
32
platlets majhor functions?
haemostasis
33
where are erythrocytes produced?
red bone marrow
34
where are granular leukocytes, neutrophils, eosinophils, and basophils produced?
red bone arrow
35
Serum albumin is used to detect ...
...diseases in blood.
36
Different types of puncture?
Venipuncture (phlebotomy)
Arterial puncture
Capillary blood
37
What are the size of plasma proteins?
Large in size
38
Plasma proteins do not cross...
... capillary walls -> generate osmotic pressure.
39
What is the function of albumins?
transport fatty acids and various hormones
40
What is the function of globulins?
antibodies and transport hormones (alpha, beta, gamma).
41
Whats the function of fibrinogen?
blood clotting coagulation
42
slide 11
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43
what are immunoglobulins also known as?
gammaglobulins
44
What are gammaglobulins/immunoglobulins?
antibodies
45
types of antibodies/immunoglobulins?
IgG
IgA
IgE
IgD
IgM
46
Which antibodies have heavy chains?
IgG
IgA
IgE
IgD
47
What is fibrinogen also known as?
AKA Factor I
48
fibrinogen is a type of...
...glycoprotein
49
how much fibrinogen is in plasma?
200 – 400 mg/dL (0.2 to 0.4 g/dL)
50
percent fibrinogen in plasma?
4% of total blood plasma
51
What is the difference between blood serum and blood plasma?
blood plasma = the liquid that is left after rbc and wbc and platelets have been removed from it.
blood serum = the liquid that is left after blood clotted and clotting factors removed.
52
what does blood plasma and blood serum contain?
plasma = contains water, electrolyites, nuteients, hormones, proteins,, waste products, gases.
serum = water, electroyltes, waste products, nutrients, hormones, proteins, but no clotting proteins.
53
function of blood serum?
diagnostic tests due to presence of antibodies and other proteins used in immune response.
54
function of blood plasma?
transporting nutrients, hormones, and waste products, and it plays a role in maintaining blood pressure and volume. contains clotting factors. and oxygen + co2.
55
Whats VLDL?
very low density lipoproteins
56
whats LDL?
low density lipoproteins
57
Whats HDL?
high density lipoprotein.
58
Lipoproteins examples?
chylomicrons, VLDL, LDL, HDL
59
total cholesterol desirable range in children?
<170 mg/dL
60
Desirable range of cholesterol in adults?
<200 mg/dL
61
high range of cholesterol in children?
>/= 200 mg/dL
62
high range of cholesterol in adults?
borderline risk = 200-39 mg/dL
high risk >/= 239 mg/dL
63
desirable range of LDL cholesterol in children <18 yrs?
desirable = <110 mg/dL
64
high range of LDL cholesterol in children?
borderline risk = 110-129 mg/dL
high risk = >130 mg/dL
65
LDL ranges in adults?
optimal = <100 mg/dL
near or above optimal = 100-129 mg/dL
borderline high = 130-159 mg/dL
high = 160 - 189 mg/dL
very high = >190 mg/dL
66
HDL-C ranges?
desirable = >59 mg/dL
borderline = 5.0-6.0
undesirable = <40 mg/dL
67
TC/HDL ranges bitch ass?
desirable = <5.0
borderline = 5.0-6.0
undersirable = >6.0
68
Range of borderline risk of atherosclerosis by cholesterol in adults?
200-239 mg/dL
69
Range of high risk of atherosclerosis by cholesterol in adults?
>/= 239 mg/dL
70
What is SpO2 ?
Peripheral Oxygen Saturation
71
What does pulse oximetry measure?
Hemoglobin saturation with oxygen
72
What are the limitations of pulse oximetry?
Gives no indication of:
- Ventilation
- base deficit
- carbon dioxide levels
- blood pH
- bicarbonate (HCO3−)
- In severe anaemia (blood will carry less total oxygen despite haemoglobin being 100%
saturated)
- Nail polish
73
Whats an erythrocyte?
red blood cell
74
WHere are erythrocytes produced?
bone marrow
75
Whats the function of erythrocytes?
Transport O2 / CO2
76
What are erythrocytes missing?
No mitochondria – use anaerobic metabolism
77
What kind of metabolism do erythrocytes use?
anaerobic metabolism
78
carbonic anhydrase makes ...
... the whole process goes faster
79
how much haemoglobin (Hb) in healthy men?
Healthy men ≈ 15 - 16 (g / dL)
80
How much haemoglobin (Hb) in healthy women?
Healthy women ≈ 13 - 14 (g/ dL)
81
Carbon monoxide is known as...
... the suilent killer since is has no color or smell. Each year in britain about 50 peopke die and 200 are severely injured by carbon monoxide poisoning.
82
Shape of erythrocytes
biconcave discs
83
Features of biconcave discs?
– large surface area to volume ratio.
– flexibility when entering small capillaries and branches.
84
What are erythrocytes missing?
No nucleus
No ribosomes
No cell division / protein production
85
Whats the usual RBC count for men?
Men: 5 to 5.4 x 10^6 ± 300.000 / mm3
86
Whats the usual RBC count for women?
Women: 4.0 to 5.3 x 106 ± 300.000 / mm3
87
Men are at greater risk for cardiovascular disease than...
... pre-menopausal women
88
Once past the menopause, womens risk for cardiovascular disease is...
...similar to men
89
What is Haematocrit also known as?
Packed cell volume.
90
How does haematocrit work?
after centrifuge, blood moves to bottom, plasma moves to the top.
91
How can haematocrit be measured?
Can be measured using a ruler.
92
What should haematocrit be in males?
40-54%
93
What should haematocrit be in females?
37-47%
94
Effect of tobacco smoking on haematocrit?
Immediate effect = decreasing PO2 (pressure of oxygen). Results in increased blood pressure.
Also chronic effects, causing increased PCV.
95
Describe Compensatory erythrocyte modulation
increased cell number
increased viscosity
increased vascular resistance
96
go look at slide 32
97
go look at slide 35
98
Where are Hematopoietic stem cells found?
located inside the bone marrow
(sternum, ribs, spine, etc)
99
What can Hematopoietic stem cells differentiate into?
differentiates into either CLP (Colony lymphoid
progenitor) or CMP (Colony
myeloid progenitor)
100
What are CLP?
Colony lymphoid progenitor
101
What are CMP?
Colony myeloid progenitor
102
What can CLP differentiate into?
1) T-Lymphocyte
2) B-Lymphocyte/Plasma cell
103
What can CMP differentiate into?
1) Erythrocyte
2) Megakaryocyte / Platelet
3) Basophil/Mast cell
4) Eosinophil
5) Neutrophil
6) Monocyte/Macrophage/Kupffer cell/Langerhans cell/Dendritic cell.
104
What are the two types of leukemia?
Lymphoblastic leukaemia
Myelogenous leukaemia
105
What is erythropoietin?
a hormone, which helps haematopoietic stem cells to differentiate into erythrocytes.
106
erythropoietin converts haematopoietic stem cells ...
...into proerythroblasts
107
Where is erythropoietin produced?
Renal tubular epithelial cells.
108
What does erythropoietin do?
turns hematopoietic stem cells into proerythroblasts
109
After hematopoietic stem cells are turned into proerythroblasts by erythropoietin, what happens then to the proerythroblasts?
Proerythroblasts are turned into erythrocytes.
110
What happens after erythrocytes are formed from proerythroblasts?
Tissue oxygenation
(pH / pCO2 / pO2 / bicarbonate)
111
How is hypovolaemia, anaemia, low hb, low flow, and pulmonary disease decreased?
Tissue oxygenation
(pH / pCO2 / pO2 / bicarbonate
112
What is the process of colony myeloid progenitor (CMP) differentiatioin into erythrocytes?
Colony myeloid progenitor -> Proerythroblast -> Basophil erythroblast -> polychromatophil erythroblast -> orthochromatic erythroblast -> reticulocyte -> erythrocyte
113
Whats the 1st generation mutation of proerythroblast?
basophil erythroblast
114
Hb level of basophil erythroblast?
low Hb
115
Whats happening to polychromatophil erythroblasts Hb level?
Hb accumulation
116
Whats happening to orthochromatic erythroblasts Hb level?
Hb accumulation + nucleus condensation
117
What changes occur in a reticulocyte erythrocyte?
- Nucleus, Golgi, mitochondria expelled
- Goes from bone marrow to capillaries -> diapedesis
118
vitamin b12 is very important for the blood. Alot of it found in...
... organ meats such as liver
119
What vitamins are found in mature erythrocytes?
Vitamin B12 (AKA cobalamin) & Folic acid
120
What is vitamin b12 also known as?
cobalamin
121
folic acid also importnat and found in ...
... greens such as broccoli
122
Whats the turnover of erythrocytes?
Rapid turnover (≈ 90 to 120 days)
123
How does nutrition deficiency affect turnover rate?
nutrition deficiency = inadequate cell production. Affects turnover rate. Better diet = shorter turnover
124
differentiation and maturation of erythrocytes is dependant on?
nutritional status.
125
Where can iron come from?
iron can come from red meats, and also vegetables + plants
126
What are the characteristics of iron-deficiency anaemia?
Impaired nuclear division & maturation &
damaged cytoskeleton
Fragile membrane – short lifespan
127
What does hypochromic mean?
hypochromic = low in colour
128
How does blood look in iron deficiency anaemia?
1) Hypochromic microcytic cells
2) Poikilocytosis (variation in shape)
3) Anisocytosis (variation in size)
129
What are the main clinical lab findings in iron-deficiency anaemia?
Parameter Change
Haemoglobin Down
Haematocrit Down
Red blood cell distribution width Up
Mean corpuscular volume Down
Erythropoietin Up (not always)
Ferritin Down
Serum iron Down
Serum transferrin Up
Total iron binding capacity Up
130
What is the function of ferritin?
intracellular protein storing iron and releasing it in a controlled fashion. Act as
buffer to prevent iron deficiency / overload
131
What is the function of transferrin?
iron-binding blood glycoprotein which controls levels of free iron in plasma
132
What is pernicious anaemia also known as?
Biermer's anaemia / Addison's anaemia / Addison–Biermer anaemia
133
Pernicious anaemia involves...
... a problem in the alimentary cannal causing causing problems with absorbing b12
134
What and where is Pernicious anaemia?
Gastrointestinal tract – Vit B12 malabsorption
135
what kind of atrophy happens in Pernicious anaemia?
Gastric mucosa atrophy -> incapacity to produce normal gastric secretion
136
What is the function of gastric gland parietal cells?
Produces intrinsic factor which binds to B12
137
What does intrinsic factor bind to?
binds to specific sites in the brush border membrane - ileum cells -> pinocytosis
138
What does megaloblast mean?
an unmatured cell (blastic), but is still big (mega)
139
What causes megaloblastic anaemia?
Folic acid deficiency
140
What causes folic acid deficiency?
Poor nutrition
Coeliac disease
141
What is enlarged erythrocytes called?
Macrocytosis
142
What is Microcytic hypochromic anaemia?
smaller than normal red blood cells (microcytic), with less haemoglobin content, causing a paler than normal appearance (hypochromic).
143
What is Microcytic hypochromic anaemia caused by?
- rapid haemorrhage
- chronic haemorrhage
- small erythrocytes - haemoglobin deficiency.
- iron losses > iron absorption
144
Aplastic anaemia is common in people suffering with...
...cancer
145
People with aplastic anaemia have no...
... have no functional bone marrow.
146
Aplastic anaemia can be caused by...
... gamma radiation / excessive X ray.
147
Aplastic anaemia can result in...
...death within a few weeks.
148
Define lytic.
lytic = lysis ; splitting apart
149
What are the membranes of erythrocyte like in Haemolytic anaemia?
Fragile membranes
150
What is Haemolytic anaemia?
rupture of red blood cells through capillaries due to turbulence and pressure. variation. Causes low rbc count, causing anemia.
151
In Haemolytic anaemia, red blood cells have a shortened...
... life span
152
What are the three types of Haemolytic anaemia?
1. Hereditary spherocytosis (Minkowski–Chauffard syndrome)
2. Sickle-cell disease
3. Erythroblastosis fetalis -> Haemolytic disease of the new-born
153
What are the red blood cells like in Hereditary spherocytosis
(Minkowski–Chauffard syndrome) ?
the blood cells have a round / ball shape, making it harder to squeeze through gaps when delivering gases.
154
Incidence rate of Hereditary spherocytosis (Minkowski–Chauffard syndrome)?
Incidence ≈ 1:5000 (Caucasians)
155
Shape of erythrocytes in Hereditary spherocytosis (Minkowski–Chauffard syndrome)?
Sphere-shaped erythrocytes
156
In Hereditary spherocytosis (Minkowski–Chauffard syndrome), erythrocytes have low resistance to...
...turbulence & pressure variation
157
Hereditary spherocytosis (Minkowski–Chauffard syndrome) can cause what disorder?
splenomegaly
158
what is splenomegaly?
enlargement of the spleen
159
Clinical severity of Hereditary spherocytosis (Minkowski–Chauffard syndrome)?
Clinical severity varied
= MCS exhibits incomplete
penetrance in its expression
160
What is sickle cell disease?
Autosomal recessive genetic blood disorder; a mutation that causes Haemoglobin S
161
Whats the genetic condition that causes sickle cell disease?
HbS homozygous
162
Whats is HbS homozygous referred to as?
HbSS
163
What is HbS homozygous?
When an individual has two copies of the sickle cell gene from both parents.
164
What are heterozygous carriers of sickle cell disease referred to as?
condition is referred to as HbAS
165
What mutations result in sickle cell disease?
Mutation in 6th codon of β goblin gene
166
What kind of mutation is sickle cell disease?
Point mutation in the β-globin chain of haemoglobin
167
What happens to erythrocytes in sickle cell disease when exposed to low PO2 (oxygen pressure)?
Crystal-shape precipitation (polymerisation) when exposed to low PO2
168
What is Erythroblastosis fetalis ?
Haemolytic disease of the new-born
169
What happens in Erythroblastosis fetalis?
Rh+ Foetus erythrocytes -> attacked by Rh- mother’s antibodies
170
What is Polychromasia (or polychromatophilia)?
the presence of a high number of immature erythrocytes (erythroblasts) in the blood, which were release prematurely from bone marrow.
May involve crenated cells.
171
What does Polychromasia (or polychromatophilia) indicate?
an increased rate of red blood cell production
172
What are crenated cells?
RBCs that have a spiky or abnormal shape because of changes in the membrane.
173
What is Primary polycythaemia?
overproduction of red blood cells, white blood cells and also platelets in bone marrow.
174
What is Primary polycythaemia also known as?
Polycythemia vera (PCV) or erythraemia
175
Haematocrit in Primary polycythaemia?
Haematocrit = 60 to 70%
176
What is the RBC count in Primary polycythaemia?
7 to 8 million / mm3
177
What causes Primary polycythaemia?
Genetic aberration -> haemocytoblast cells don’t stop proliferating
178
What are the affects of Primary polycythaemia on the blood?
- Increased blood volume – ingurgitation
- Increased viscosity
- Decreased blood flow
179
What is the RBC count in Secondary polycythaemia?
6 to 8 million / mm3
180
Secondary polycythaemia causes...
... Chronic hypoxia
181
What is Secondary polycythaemia also known as?
Physiological polycythaemia (naturally increased erythropoietin)
182
What is Physiological polycythaemia ?
naturally increased erythropoietin
183
What is hypoxia?
a deficinency of oxygen in the blood.
184
What is blood doping?
Blood doping refers to when an athlete artificially increases the number of RBC in their body to enhance athletic performance. - This is typically done to improve endurance and oxygen delivery to muscles during intense exercise.
185
Blood doping can cause ...
... Congestive heart failure
186
Do people living in the mountains have high or low oxygen levels?
Low. Can cause hypoxia.
187
What are White blood cells also known as?
leukocytes
188
What do leukocytes contain and not contain?
Contain nuclei but not Hb
189
What do leukocytes defend against?
Defend body against pathogens
190
What do leukocytes remove?
Removes toxins, wastes, and damaged cells.
191
What do leukocytes detect?
detect chemical signs of damage.
192
How many classes and groups of white blood cells?
5 classes, 2 groups
193
What are the two groups of leukocytes?
Granular (granulocytes) and Agranular (agranulocytes)
194
neutrophils receives signals for...
...recruitment
195
neutrophils travel to the bloodstream anf from there will ...
... profuse into intercellular space (the space between cells).
196
Neutrophil have the ability to ...
... penetrate through cells to the other side, without causing any damage. This process is called diapedesis.
197
where are neutrophils stored?
bone marrow
198
the bone marrow signals for...
...recruitment (of neutrophils).
199
neutroophils travel in blood stream then profuse into...
...intercellular spaces.
200
What kind of movement does neutrophil have?
amoeboid movement, allows them to phagocytose
201
Neutrophils cas phagocytose what?
bacterial/viral toxins, degeneration products (cell debris)
202
slide 66
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203
What does the complement system consist of?
Opsonization; Chemotaxis; Cell Lysis; Clumping of antigen
bearing agents
204
in the blood are called monocytes. Once in the tissues, they are known as ...
...macrophages
205
Depending on where we find the monocytes, we can....
.... call them different names.
206
Function of macrophages/monocytes?
detect and engulf viral poteins, dead cells, bacteria whichthought any soecific immunity
207
slide 67
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208
process leading to inflammation?
pathogen = bacteria./fungus/virus triggers infection then inflammation when other white cells attracted.
209
inflammatory response triggers prod of many chemical signals. Triggers neighbouring cells to release...
histamine, serotonin, prostaglandins, complement system reaction products, lymphokines (T cell).
210
what are lymphokines?
chems that recruit things like t cells.
211
inflammation also causes vasodilation, which is when...
...Blood vessel loosens. tissue becomes hot, red, swollen.
212
inflammation calso causes increased permeability (vascular permeability). what is this?
as a result of vasod, opening of pores in cell walls, allows interstitial liquid to leak into intercellular space. Can cause oedema.
213
inflammation also causes increased fibrinogen - coagulation.
214
what is recruited to the site of infammation?
immune cells recruited to clear the area.
215
what disease can inflammation cause?
oedema
216
how is inflammation controlled?
TNF-alpha, Interleukin 1, GM-CSF (granulocyte-macrophage
colony-stimulating factor), G-CSF (Granulocyte colony-stimulating factor), M
CSF (Monocyte colony-stimulating factor)
217
what liquid does inflammation result in?
Suppuration / pyogenesis (Pus)
218
dd
dd
219
What are Eosinophils ?
they are very weak macrophages
220
What do eosinophils present?
chemotaxis.
221
Number of eosinophils increase in ...
...parasitic infections.
222
What do eosinophils release?
adhere and release hydroplytic enzymes and highly reactive oxygen species (ROS).
223
What are basophils ?
Large mastocytes (mast cells) in surrounding capillaries
224
What do basophils release?
heparin and histamine
225
why do basophils release histamine?
histamine released to resolve allergic reaction. Anti histamines taken to drive back this response.
226
basophils have roles in what?
role in allergy and inflammation
227
What kind of enzyme are basophils?
Lysosomal enzymes
228
what binds to basophils?
Specific IgE binds to basophil
229
lysis =
release
230
where are t cells produced and where are they matured and specialised?
thymus
231
T cell specificity –
Millions of different antigens
232
where do b cells mature?
mature in liver during foetal life
in bone marrow after birth
233
b cell diversity
same cell produces many types of humoral immunity (ab)
234
millions of lymphocyte clones stored in...
lymphoid tissue – subsequent infection triggers exponential proliferation
235
The two types of lymphocytes?
B lymphocytes and t lymphocytes.
236
What are B lymphocytes responsible for?
production of antibodies (Humoral immunity Ab).
237
What are T lymphocytes responsible for?
cellular immunity - the cell itself attacks the enemy (activated t lymphocytes) - go to front line of infection.
238
Lymphocyte action depemds on...
...exposure to antigens (acquired immunity)
239
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240
73
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241
What is leukocytosis?
increased leukocytes.
242
What can cause leukocytosis?
Generally infection, also cancer, drugs, chronic stress
243
What is neutrophilia?
increased neutrophil granulocytes
244
What can causes neutrophilia?
Acute infections, certain types of leukaemia, haemolysis, drug intoxication, etc.
245
What is lymphocytosis?
increased lymphocytes
246
What causes lymphocytosis?
Mumps, rubella, infectious mononucleosis, lymphatic leukaemia, pertussis, pyogenic infections in childhood, etc.
247
What is monocytosis?
increased monocytes
248
What causes monocytosis?
Chronic pyogenic infections, bacterial endocarditis, infectious hepatitis, monocytic leukaemia, rickettsial disease, etc.
249
Whats eosinophilia?
increased eosinophils
250
What can cause eosinophilia?
Skin diseases, infestations, hay fever, asthma, allergic responses, Hodgkin disease.
251
Whats basophilia?
increased basophils
252
What could cause basophilia?
Leukaemia, advanced anaemia, malaria, lead poisoning, etc.
253
Someone with eosinophil could be infested with....
....could be infested with parasites, on the surface of our bodyy and the inside of the body.
254
What can neutrophils, eosinophils, and basophils be categorised into?
polymorphonuclear granulocytes
255
what percentage of leukocytes are neutrophils?
62%
256
what percentage of leukocytes are eosinophils?
2.3
257
what percentage of leukocytes are basophils?
0.4
258
what percentage of leukocytes are monocytes?
5.3
259
what percentage of leukocytes are lymphocytes?
0.3
260
normal leukocyte count?
7000 / ul
261
define leukopenia?
abnormal lowering of leukocytes
262
define neutropenia?
decreased neutrophils
- Cancer drugs, hereditary disorders of the bone marrow, radiation
therapy, vitamin B12 and folate deficiency, etc.
263
define Lymphocytopenia
decreased lymphocytes
- Aids, Hodgkin's disease, cancers of the lymphatic system, certain types
of leukaemia, malnutrition, etc.
264
how many platelets per ul?
* ≈ 150,000 – 450,000 /μL
265
Platelets are a major participant in ...
... clotting system
266
how often are platelets replaced?
* Continuously replaced (9-12 days)
267
how many platelets are held in the spleen?
* 1/3 held in the spleen
268
the megakaryocyte (MK) cytoplasm forms what?
forms long pseudopodial processes which penetrate the sinusoidal endothelial cells releasing platelets into venous sinuses and into the peripheral blood.
269
Platelets are simply...
...small fragments of megakaryocyte cytoplasm released into the blood.
270
what is haemostasis?
* The cessation of bleeding
– prevents loss of blood through vessel walls
– Most effective in smaller vessels
271
the three phases of haemostasis?
– vascular phase (vascular spasm) (first phase)
– platelet phase (second phase)
* Platelet adhesion
* Platelet aggregation (platelet plug)–
- coagulation phase (blood clotting)
272
what happens in platelet phase?
platelet phase = platelets will land, with finbriongen which forms into fibrin, which forms a clot to stop bleeding.
273
what is plasmin?
plasmin is an enzyme which converts fibrin into fibrin degradation products.
