The Immune System - Part 1 (week 7) Flashcards
what is the blood made up of? (2 points)
- blood is made up of ‘formed elements’ (eg - cell fragments, platelets) and mostly water
- erythrocytes, leukocytes and platelets
state the function of plasma
plasma carries blood cells, protein, nutrients, metabolite products, and other molecules being transported around the body
state what it is meant by the key term - haematocrit
haematocrit refers to the percentage of blood that is made of erythrocytes compared to the total blood volume (men = 45%, women = 42%)
state the approximate blood volume and erythrocyte volume of an average 70kg man
BV - 5.5 L
EV - 2.5 L (0.45 x 5.5)
state what it is meant by the key term - bulk flow
bulk flow refers to the rapid flow of blood throughout the body
state the function of erythrocytes
erythrocytes function to transport O2 and CO2
state 3 structural facts about erythrocytes
- biconcave
- fluid membrane
- large SA
- no nuclei or organelles
- no DNA or RNA (no mitosis)
state the average amount of haemoglobin (Hb) values (g/100ml) in both men and women
men = 15.5g / 100 ml women = 14g / 100 ml
state the location of erythropoiesis
erythropoiesis occurs in the bone marrow
state what it is meant by the key term - reticulocytes
young erythrocytes in bone marrow contain few ribosomes which produce a web-like appearance (reticular) when stained - reticulocytes
what occurs within one day of being a reticulocyte
ribosomes are lost within 1 day of a reticulocyte, so no protein production occurs henceforth
erythrocytes have a relatively short life span. approximately how long is their life span?
120 days
what is the breakdown produce of Hb, and what is it’s effect
- BILIRUBIN - the breakdown product of Hb is called bilirubin
- gives plasma a yellow colour when returned to the circulation
the production of erythrocytes required what 4 nutrients (macro/micro)?
carbohydrates, amino acids, lipids, iron
- state the function of iron
2. state the percentages of iron in 3 different locations in the body
- O2 binds to iron via Hb
- 50 % iron found bound to Hb
- 25 % in body cells
- 25 % bound to Ferritin in the liver
state what it is meant by the key term - transferrin
Transferrin is a plasma iron-transporter protein
what is Folic Acid ? and where can it be found ?
- Folic acid (vitamin B9) it is required to synthesis the nucleotide Thymine
- is found in leafy plants, yeast and liver.
state what it is meant by the key term - Vitamin B12
Vitamin B12 is needed by Folic acid. it is found in animal products and is used to aid the absorption of Folic acid in the GI tract
state what it is meant by the key term - anaemia
anaemia is the decrease in the ability of the blood to carry oxygen and is due to 3 things: A) a decrease in the total number of erythrocytes, B) low Hb per erythrocyte, C) a combination of both
state 5 causes of anaemia
- dietary deficiencies of iron (iron deficiency anaemia), Folic acid or Vitamin B12
- bone marrow failure due to toxins or cancer
- blood loss from body (haemorrhage)
- inadequate secretion of erythropoietin (EPO) from the kidneys via kidney disease
- excessive destruction of erythrocytes (eg - sickle cell disease)
what hormone, and where is it secreted, stimulates erythropoiesis
erythropoietin, secreted by the kidneys, is the hormone responsible for stimulating erythropoiesis
state the 7 steps in erythrocyte replacement
- decrease in O2 delivery to kidneys
- kidneys increase erythropoietin secretion
- plasma erythropoietin levels increase
- bone marrow increases erythrocyte production
- blood Hb concentration increases
- blood O2 carrying capability increases
- restoration of O2 delivery
state what it is meant by the key term - haemostasis
haemostasis is the term used to define the stoppage of bleeding
when a blood vessel is ruptured, what is the response, and why (2 points)
- response is to constrict - slows blood flow to that area
2. presses endothelial surfaces together inducing a ‘stickiness’ which ‘glues’ them together
within the microcirculation, the reduction of bleeding depends on what two processes?
- the formation of a platelet-plug
- blood coagulation (clotting)
*platelets used in both processes
state what it is meant by the key term - Fibrinogen
Fibrinogen (a plasma protein) supports the platelet plug
explain the 4 steps (not general points) of how platelets are used in blood loss
- injury to vessel disturbs endothelium - exposes collagen
- platelets adhere to collagen via an intermediary - von Willebrand factor (vWF)
- platelets release ADP and serotonin that induce changes in metabolism, shape and surface protein expression on the platelets - platelet activation
- also release actin and myosin to aid contraction
state the name of the intermediary which aids platelets to adhere to collagen
von Willebrand factor (vWF)
state the value of the total number of erythrocytes in the blood
5,000,000 / mm^3 of blood
state the value for the total number of leukocytes in the blood
7000 / mm^3 of blood
state the percentage of leukocytes that are neutrophils in the blood
50-70 %
state the percentage of leukocytes that are eosinophils in the blood
1-4 %
state the percentage of leukocytes are basophils in the blood
0.1-0.3 %
state the percentage of leukocytes that are monocytes in the blood
2-8 %
state the percentage of leukocytes which are lymphocytes in the blood
20-40 %
state the total number of platelets in the blood
250,000 / mm^3 of blood
