Blood (p1) Flashcards
What are distribution (transport) functions of the blood?
a) oxygen and nutrients - dleivery of O2 to tissues or nutrients
b) metabolic wastes - conveying metabolic wastes to the liver or lungs (CO2 as a waste product)
c) hormones - many are transported through the blood
What are blood components? Cellular and physical components?
Blood - Only FLUID tissue in the body (formed elements are suspended in plasma)
Cellular;
- erthrocytes (RBCs) -> transportation of oxygen
- leucocytes (WBCs) -> protection against microorganisms
- platelets -> for forming blood clots
Physical;
- O2 rich colour is scarlet, O2 poor colour is dark red
- more dense, viscous than water
- pH = 7.35-7.45, this is monitored al the time and if pH is not within this range, there are mechanisms that kick in to bring it back (acidosis vs alkalosis)
- ~8% of our body weight (lower in females than in males)
What are regulation functions of the blood?
a) body temperature (circulatory system) - distribution, onservation, dissipation
- core body (brain, visceral organs) temp = most important
- blood flow is controlled through the body
- blood can also carry heart -> the ridding of extra heat
b) pH in body tisses (plasma proteins, bicarbonate reserve)
- can soak up extra H+ ions so the blood doesn’t become too acidic
- CO2 + H2O <-> H2CO3 <-> HCO3- + H+
c) adequate fluid volume - enough fluid volume for good blood pressure
What are protection functions of the blood?
a) platelets, plasma proteins - protection against blood loss (formation of blood clots)
b) antibodies, complement, WBCs - protection against infection (components of the immune system)
what consists blood plasma?
- 90% water + many solutes
- plasma proteins
- albumin
what are plasma proteins?
functional proteins which remain in blood
- produced in the liver
what is albumin?
carrier of various molecules (ex. steroids), an important blood buffer and a major osmotic protein
- 60% of all plasma proteins
- blood buffer -> can soak up extra H+ ions to prevent acidic blood
- holds a bunch of water to maintain adequate blood pressure
What is the major osmotic ion?
Na+, sodium = most prevalent ion in bloodstream
- responsible for making sure there are enough fluids in the body
- monitors blood osmolarity (acidity)
If you were to spin a blood sample in a centrifuge, what would be the result of the different layers?
Plasma = top layer
- least dense component
- fluid compartment
- ~55% of whole blood
Buffy coat = middle layer
- leukocytes and platelets
- <1% of whole blood
Erthrocytes = bottom layer
- RBCs
- ~45% of whole blood (hematocrit)
- most dense component
Formed elements = erthrocytes and buffy coat (leukocytes and platelets)
Why do we say that leukocytes only are complete cells?
Leukocytes have nuclei whereas RBCs once they are in the blood no longer have a nuclei
Platelets also dont have a nuclei, only have vesicles for clotting
Most formed elements are short-lived/disposable and are constantly replaced by bone marrow, this is why we call them formed elements rather than cells
What is the function of the spectrin protein?
Responsible for allowing RBCs to slightly change their change, found in the plasma membrane
What is the functional anatomy of an erthrocyte?
Biconcave discs (no nucleus) = “bags of hemoglobin”
- other proteins maintain PM and regulate cell shape (spectrin)
- RBC transport O2 from lungs to tissues, transports ~20% of CO2 back to lungs
- depression in the centre to indicate where the nucleus was before it was ejected
What are some specialized characteristics of erthrocytes that optimize function?
1) Small size and biconcave shape gives a large SA to V ratio
2) >97% non-water composition is hemoglobin
3) No mitochondria, generates ATP anaerobically ∴ they dont use any of the O2 they transport
- RBCs are the major factor contribution to blood viscosity, rate of blood flow is inversely affectd by RBC count
- if RBCs increase, blood flow decreases (slower because its much thicker)
What is hemoglobin?
Hemoglobin (Hb) = protein globin bound to red heme pigment
What is globin?
globin = 4 polypeptide chains (2 α and 2 β)
- 4 Fe-containing central heme groups
- each Fe can reversibly bind to one molecule of oxygen
Why is Hb contained in erthrocytes rather than being a plasma protein?
- keeps it from fragmenting and being lost
- keeps it from contributing directly to osmotic pressure and blood viscosity
What do O2 and CO2 combine with in regard to a Hb?
O2 combines with heme group
CO2 combines with globin part
This causes formation of carbaminohemoglobin
Differences in where O2 and CO2 combine allows for no competition but they do still influence each other