Flashcards in Week 4 Deck (36):
What are physical characteristics of blood?
red, sticky, opaque, metallic taste, accounts for 8% body weight
Main functions of blood
transport- moving substances around body
Regulation- maintenance of homeostasis
Protection- protects body from trauma and invasion.
What type of transport does blood perform?
deliver oxygen to body cells from lungs.
delivery of CO2 to lungs
transportation of lungs
What does the blood regulate?
Maintenance of body temperature
maintenance of pH levels
Maintenance of appropriate blood volume
How does the blood protect?
Prevention of blood loss by forming clots
prevention from infection- white blood cells, antibodies
What is the composition of blood?
Fluid connective tissue, plasma and formed elements
what percent of the blood is plasma?
What are the three components of plasma?
water, electrolytes and proteins
What percent do erythrocytes take up?
What is the remaining 1% of the blood?
What is hematocrit?
The percent of erythrocytes in the blood
Why is a percentage used and not a count?
A percentage is used because erythrocytes can vary in size, therefore if you count them it won't be accurate to compare between people as sizes may be different.
What is polycythemia?
Polycythemia is when the percentage of RBC is too high
What is it called when there is a low percentage of RBC?
How big are erythrocytes?
What shape do RBC have and why?
biconcave disc, they have this so their surface area is large and can be flexible to move through small spaces.
What is hemaglobin made up of?
Each hemaglobin has four red heme groups bound to the protein globin with an iron in the centre of each heme.
Where does oxygen loading occur and how does it work?
Oxygen loading occurs in the lung.
1. oxygen diffuses from alveoli into blood
2. then diffuses from blood into erythrocytes
3. oxygen binds to iron in haemoglobin
4. blood becomes ruby red
Where does oxygen unloading occur and how does it work?
Oxygen unloading occurs in body tissues.
1. oxygen detaches from iron in haemoglobin
2. oxygen diffuses from erythrocytes into blood
3. diffuses from blood into tissue cells
What is erythropoiesis?
erythrocyte production, approximately 2 million produced every second.
How does erythropoiesis work?
1. Hypoxia (lack of oxygen) due to decreased RBC count, decreased amount of hemaglobin, decreased availability of oxygen
2. kidney releases erythropoietin
3. erythropoietin stimulates bone marrow
4. enhanced erythropoiesis increased RBC count
5. ability to carry oxygen rises.
What is anemia?
Anemia occurs when blood oxygen carrying capacity is too low to support normal metabolism.
What causes anemia?
iron deficiency, pernicious anemia (lack of vit B12). sickle cell anemia (abnormal hemaglobin), aplastic anemia (bone marrow not producing enough RBC)
What are the two types of polycythemia?
primary (bone marrow cancer) and secondary (high altitude, less oxygen available)
What do leukocytes do?
Defend against disease, provide surveillanec, destroy infected or cancerous cells
What does diapedesis mean?
Leukocytes can do this, move between blood stream and into tissue.
What are the two types of leukocytes?
Granulocytes and agranulocytes
Name the granulocytes
neutrophil, eosinphil and basophil
Name the agranulocytes
Lymphocytes and monocytes
What are platelets?
Cytoplasmic fragments, last formed element of the blood
What is the process to stop bleeding through a wound?
1. vascular spasm - smooth muscle contracts, causing vasoconstriction
2. platelet plug formation- platelets stick to exposed collagen fibres
3. coagulation- reinforces platelet plug with fibrin
If someone's blood type is A+, what antigens do they have?
They have A antigens and Rhesus antigens.
If someone does not have a rhesus antigen, are they positive or negative?
They would have a negative blood type
What blood group is known to be a universal donor?
What blood group is known to be the universal recipient?