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Cells to systems > Lecture 9 > Flashcards

Lecture 9 Flashcards

1
Q

What can the fluid material circulation the cardiovascular system do

A

maintains homeostasis

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2
Q

What does Plama contain

A 
v Rich in protein – albumin, globulins, Ig,
fibrinogen
v Regulatory substances, nutritional
substances, salts, waste
v Removal of fibrinogen-fibrin → serum
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3
Q

What are the percentages of material in plasma

A 
• 90-92% water.
• 6-7% proteins
• Albumin – colloid osmotic pressure
• Globulin – enzymes, antibodies
• Fibrinogen – polymerizes into fibrin
during coagulation or clot formation
• 2-3%
• Fats
• Carbohydrates (glucose)
• Electrolytes
» Bicarbonate, calcium, chloride,
magnesium, phosphorus, potassium,
sodium
• Gases (O2, CO2)
• Chemical messengers
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4
Q

What is the name for red blood cells

A

erythrocytes

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5
Q

what is the name for white blood cells

A
  • leukocytes
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6
Q

What are the amount of RBC(erythrocytes) in mammals

A

v Present in large numbers (500-1000 x > leukocytes)
v Measured in millions (106/mm3 (µl), 109/ml or 1012/L)
v Variation in number (6-14 x106/mm3) and size (4-12 µm) in
domestic species
v RBC number varies in an individual
• nutritional state, physical activity, age

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7
Q

What is the structure composition of RBC

A 
v commonest blood cell
v Water (60%) + haemoglobin (40%)
v Biconcave disk – maximises surface
area
v No nucleus in mammals (exceptions
– foetus)
v Stains eosinophilic
v Ultrastructure:
• homogenous, electron dense
• no organelles in mature mammalian
RBC
• Haemoglobin
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8
Q

What is the function of RBC

A

v Carry O2, CO2 & H+ (buffering role)
v Life-span is about 80 d in cats; 100-
120 d in dogs & humans; 150 d in
horses, cattle & sheep

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9
Q

What are Reticulocytes

A 
immature red blood cells
v 1% of the red cells in the human
body.
v develop and mature in the red bone
marrow
v circulate for about a day in blood
before developing into mature RBC
v Mammalian reticulocytes do not
have a cell nucleus
v Mammalian reticulocytes do have a
reticular (mesh-like) network of
ribosomes (basophilic stain)
v Increase in circulating reticulocytes
indicates increased RBC production
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10
Q

What animal’s RBC lose their nucleus and mitochondria

A

mammals

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11
Q

What was the reason for losing nucleus and mitochondria

A

v Allows them to carry more haemoglobin, and
more oxygen
• Doesn’t seem to be a problem in other groups
• Birds do have air sacs
v Bi-concave disc aids diffusion
v No mitochondria, so don’t use the oxygen
they carry
• Produce energy by glycolysis
v Short answer – we don’t know why
mammalian RBC loose their organelles

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12
Q

How oxygen can a haemoglobin carry

A

4

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13
Q

Where does majority of the CO2 go to

A

89% go to erythrocyte

11 go to the blood

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14
Q

How does CO2 enter the cell

A

Aquaporin (AQP1)

Rhesus

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15
Q

Why can RBC carry CO2

A 
Most is transported by the
RBC as bicarbonate ions or
combined with haemoglobin
v RBC have high levels of carbonic
anhydrases so more bicarbonate
is produced than in plasma
v Cl-HCO3 exchanger transports
bicarbonate out of RBC,
promoting formation of more
bicarbonate within the RBC
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16
Q

How do CO2 cross the RBC plasma membrane

A

Classical membrane
diffusion
v Diffusion through pores –
“gas channels”

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17
Q

What are involved in haemostasis (clotting)

A

platelets

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18
Q

Structure of platelets

A

v Small, ovoid bodies
v Cytoplasmic pieces ‘budded off’ from
megakaryocyte

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19
Q

Lifespan of platelets

A

Lifespan 8-10 days (sequestered in the

spleen)

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20
Q

What is the composition of the platelet granules

A

• Dense granules
v ADP, serotonin (a vasoconstrictor), calcium
• Alpha granules
v Thrombospondin, fibrinogen

21
Q

How does platelets clot blood

A

aggregation and coagulation

22
Q

What is aggregation for blood clotting

A

platelet adherence
Aggregation – associated with endothelial cell injury;
formation of platelet plug

23
Q

What is coagulation for blood clotting

A

fibrin formation
– initiated at larger sites of injury;
formation of a clot (thrombus)

24
Q

What events does injury trigger

A 
2 events 
v The activation and deposition
of platelets at a wound site
v Activation of the coagulation
pathway
• Prothrombin converted to
thrombin
• Thrombin causes fibrinogen
to polymerize into fibrin
v These lead to the formation
of a fibrin seal on the
deposited platelets
v “Plugs the leak”
25
Q

What is haematocrit

A

Packed cell volume (PCV),

26
Q

What are Haemopoietic stem cell (HSC)

multipotent cell

A

v they can form any
blood cell line
v Myeloid and lymphoid

27
Q

How do the stem cell differentiate

A

Controlled by lineageindependent and
lineage-specific
cytokines and growth
factors

28
Q

What is the role of hamopoiesis

A

• To maintain homeostasis:
v Short lifespan of mature blood cells requires continual
replacement throughout life
• Enable a rapid response to life-threatening conditions
:
v Blood loss
• RBC numbers are tightly regulated
v Infection
• WBC numbers increase to fight infection

29
Q

What cells need to be removed and replaced?

A

dangerous cell types:
v Neutrophils and eosinophils
• Once activated they are damaging to surrounding tissues

30
Q

Where are the sites of haomopoiesis for embryo

A

Yolk sac, liver and spleen

31
Q

Where are the sites of haomopoiesis for foetus

A

Liver, spleen and bone marrow

32
Q

Liver, spleen and bone marrow juvenile

A

• Bone marrow – reducing sites with age

33
Q

• Bone marrow – reducing sites with age adult

A

Bone marrow – proximal ends of
femurs, pelvic flat bones, vertebrae
skull, ribs and sternum

34
Q

What does haemopoietic stem cells (HSC) interact with in the bone marrow

A

v Stromal fibroblasts
v Osteoblasts
v Endothelial cells
v Extra-cellular matrix

35
Q

What does receptors on HSC bind to

A

v Stromal adhesion molecules
v Membrane bound stromal growth
factors
v Soluble growth factors

36
Q

What does receptor binding control

A

gene

expression and directs development

37
Q

What cause erythrorpoiesis? (differentiating into erythrocyte)

A

Stimulated by

erythropoietin (EPO

38
Q

What causes thrombopoiesis?? (differentiating into megakarycyte)

A

Stimulated by

thrombopoietin (TPO)

39
Q

What is erythropoiesis controlled by

A 
controlled by
erythropoietin (EPO)
produced by fibroblast-like
cells in the cortex and outer
medulla of the kidney
v Shortens cell cycle time
v Increased rate of maturation
v Increased rate of release from
bone marrow
40
Q

When does exocytosis of nucleus happen during erythropoiesis?

A

When normoblast form into reticulocyte

41
Q

When does the mitochondria and ribosomes be lost

A

When Reticulocyte form into erythrocyte

42
Q

What does increase presensce of circulating reticulocytes

A

Indicative of recent increase in

erythropoiesis

43
Q

What does Decrease in oxygen delivery to tissues leads to

A

o tissues leads to the

p

44
Q

What causes Decreases in oxygen level (hypoxia)

A 
§ Low blood volume
§ Anaemia
§ Low haemoglobin
§ Poor blood flow
§ Pulmonary disease
45
Q

Anaemia

A

reduction in the ability of blood to carry oxygen

46
Q

Polycythaemia

A

abnormally increased number of RBC

v Bone marrow cancer or abnormal erythropoietin production

47
Q

Erythrocytes

A

Oxygen and carbon dioxide transport

48
Q

Platelets

A

Haemostasis

49
Q

Erythropoiesis

A

Role of hypoxia and erythropoietin

Cells to systems (25 decks)

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