Lecture 23

Question 1

Blood is ____ of total body weight

Answer 1

• 7%
• 5L in men
• 4L in women

Question 2

Blood

Answer 2

• a connective tissue with very water extracellular matrix (1/4 of ECF) and cellular elements
• RBC (erythrocytes) —> gas transport
• WBC (leukocytes) —-> serve different immune functions
• platelets (thrombocytes) —> important for clotting and hemostasis. They used to be cells and then got broken into tiny little bits

Question 3

How can blood components be separated

Answer 3

If we take a sample of blood and put it into a small capillary tube and spin it really quickly by the process of centrifugation heavy stuff will settle and light stuff will stay suspended in the solution

Question 4

Hematocrit

Answer 4

Tells us about our red blood cell count

Question 5

If RBC count is low you can be diagnosed with _____

Answer 5

Anemia

Question 6

Hematopoeisis

Answer 6

• Synthesis of new blood cells occur in red bone marrow of pelvis, ribs, cranium and proximal ends of flat bone
• within active bone marrow 25% of the developing cells will become RBCs and 75% will become WBCs because we don’t need as many RBCs and we synthesize WBCs more often

Question 7

Pluripotent hematopoietic cell

Answer 7

A pool of cells that can divide and differentiate and become any one of RBC, WBC or platelet

Question 8

Megakaryocyte

Answer 8

• plate that gets smashed into platelets
• a large cells that has started mitosis many times but never finished and then is smashed and we get platelets

Question 9

Cytokines

Answer 9

Controls the production and development on blood cells
- erythropoietin is synthesized by the kidneys and goes to red bone marrow and turns up production for RBCS
- thrombopoietin is synthesized by the liver and increases differentiation of megakaryocytes and platelet production

Question 10

WBC and RBC life span

Answer 10

WBC: 6-12 hours
RBC: 120 days

Question 11

What happens when there’s low O2 level in arterial blood

Answer 11

Hypoxia

Question 12

Name 2 cytokines and their functions

Answer 12

1. erythropoietin: synthesized by the kidneys and goes onto bone marrow and turns up production of erythrocytes
2. thrombopoietin: synthesized by the liver and influences growth of megakaryocytes and platelets

Question 13

RBCs

Answer 13

• job is to cart oxygen around the whole body therefore they are packed with oxygen binding protein called hemoglobin
• 120 day lifespan
• biconcave and bendy
• no nucleus or mitochondria

Question 14

hemoglobin

Answer 14

• has 4 subunits and at the center of each of these subunits contains a chemical structure called a porphyrin and at the center of this ring is iron which is the oxygen binding site
• can carry 4 oxygen molecules
• is cooperative (binds none or all)

Question 15

Formation of a platelet plug

Answer 15

• due to damaged vessel elements like collagen are exposed to inside of vessel
• collagen is sticky so it sticks to platelets and releases platelet factors
• platelet factors recruit more platelets so that all those small bits of platelets can stick together and form a tiny bandaid solution called a platelet plug

Question 16

2 ways we can loose RBC

Answer 16

1. Accelerated RBC loss
   - blood loss
   - hemolytic anemia (RBC are destroyed faster than they are made: sickle cell anemia (genetic) —> 1 amino acid substitution that bust RBC, RBC is no longer round and biconcave and malaria (acquired) —> carried by mosquitoes and if you have sickle cell anemia you are protected
2. Decreased RBC production
   - aplastic anemia (drugs or radiation)
   - dietary insufficiencies (iron, folic acid or vitamin B12 deficiencies)

Question 17

Buffy layer

Answer 17

Platelets and WBC between RBC and plasma

Question 18

Totipotent

Answer 18

Can become any type of cell in the body

Question 19

Hemolytic anemia

Answer 19

When RBCs are being destroyed faster than they are made

Question 20

The coagulation cascade

Answer 20

Intrinsic pathway (from within)
- we don’t need anything other than what’s already present in the vessel
- cascade involving plasma proteins that is initiated my exposure of sticky collagen which will activate a series of coagulation factors

Extrinsic pathway (from outside)
- we need something from outside the vessel which is tissue factor
- tissue factor leaks in from ruptured vessel and activates a series of coagulation factors

MERGE POINT
- both pathways will merge to lead to activation of factor 10
- activated factor 10 will convert inactive prothrombin to thrombin
- thrombin will then convert soluble fibrinogen to insoluble fibrin
- insoluble fibrin will stick to itself and form a cross linked protein mesh net over the surface of the injury and this will trap RBC which is our clot

Question 21

Hemostasis

Answer 21

• vasoconstriction because we want to send less blood
• platelet plug
• coagulation cascade
• fibrinolysis

Question 22

Fibrinolysis

Answer 22

• tissue is repaired and clot is dissolved due to enzyme plasmin which will return insoluble fibrin to soluble fibrinogen

Question 23

What are antigens

Answer 23

If you have those antigens you can receive that type of blood

Question 24

What does the +/- associated with your blood type refer too

Answer 24

It refers to whether you carry the rhesus factor antigen

Question 25

You naturally produce antibodies to the antigens you don’t have

Answer 25

True, but does not apply to Rh

Question 26

Why cant O receive blood from blood type B

Answer 26

Because they produce antibodies against A and B Blood will agglutinate

Question 27

What blood type is the universal done

Answer 27

O- because they don’t have antigens

Question 28

What blood type is the universal acceptor

Answer 28

AB+ because they don’t have plasma antibodies

Question 29

Rh factor incompatibility during pregnancy

Answer 29

- you do not naturally produce Rh antibodies unless exposed to it - so if dad is Rh+ and mom is Rh-, but fetus is Rh+ —> Rh antigens from fetus can enter mothers blood during delivery and in response she will develop antibodies to Rh+ - so if she gets pregnant again with and Rh+ child the antibodies she was will attack the fetal blood - to prevent inject mother with anti Rh antibodies before birth of first child