The Blood System Flashcards
Main functions of blood
TRANSPORTATION of respiratory gases, nutrients, waste and hormones
REGULATION of body temperature, pH and ion composition of interstitial fluids
PROTECTS against blood loss - clotting, against infection - immune system
what temperature can blood be
38/39 degrees Celsius
hematocrit
the packed red cell volume of blood
hematocrit percentage of blood
42% in women
45% in men
plasma percentage of blood
58% in women
55% in men
what are the products of blood spun with anti-coagulants and their constituent’s
hematocrit - RBCs
buffy coat - platelets and WBCs
plasma - water, proteins, inorganic solutes, organic substnaces
what does albumin carry and what does it maintain
carrier of lipid soluble substances (drugs, hormones)
maintains osmotic pressure
types of globulins and their roles
alpha and beta - transport water insoluble substances including clotting factors
gamma - antibodies
fibrinogen
inactive precursor of clot’s fibrin meshwork
contents of erythrocytes
crucial enzymes for glycolysis and carbonic anhydrase
no nucleus
contents of reticulocytes
same as erythrocytes
remnants of organelles
what properties of RBCs support their function
flat concave shape allows large surface area
flexible membrane can squeeze through capillaries
contains Hb for oxygen transport
haemoglobin
a pigment made of 4 globin chains and a heme group
haem binding to oxygen
weak and reversible so its senstive to pH changes in blood
1 oxygen molecule per group
why does oxygenated blood appear red
Hb is a pigment
high iron content is reddish when combined with oxygen
Hb O2 binding
loose and reversible
depends on PO2
Hb CO2 binding
when PCO2 is high
different binding site than O2
forms carbamino Hb
Hb CO binding
same binding as oxygen
240x higher affinity for CO
why do erythrocytes have short life spans
how long is it
no DNA so cannot synthesise proteins or divide
120 days
erythropoiesis
bone marrow generation of new red blood cells
where do old RBCs die
the spleen
what controls erythropoiesis
where does it act
erythropoietin from the kidneys in response to reduced O2 delivery
red bone marrow
when there is haemorrhage or blood loss
reticulocyte levels increase, peaks at 4-7 days
decreases by 2 weeks when Hb becomes normal
remains high in there is further blood loss
epogen
what is it used for
synthetic erythropoietin
surgery and chemotherapy
dialysis patients
doping
what are the products of haemoglobin broken down to
globin - amino acids
haem - iron (stored as ferritin), bilirubin (taken up by liver)
what is bilirubin used for
secreted into intestine in bile
metabolized into stercobilin by -gut bacteria and excreted
what food nutrients absorbed from intestines for erythropoiesis
iron, vit B12, protein, folic acid
what happens to aged and damaged RBCs
engulfed by macrophages of liver and bone marrow
why do babies get jaundice
why is it treated with UV
their liver is not developed enough to remove bilirubin
transforms bilirubin into water-soluble isomers that can be eliminated without conjugation in the liver
symptoms of anaemia
fatigue, paleness, shortness of breath, increased heart rate, and chills
causes of anaemia
nutritional
pernicious (vit B12)
aplastic (lack of erythropoiesis)
renal
haemorrhagic
haemolytic
malaria
sickle cell
polycythaemia
too many circulating RBCs
primary vs secondary polycythaemia
primary - genetic or cancer cause bone marrow to over produce
secondary - reduced O2 delivery causes over production (high altitude, sleep apnoea, heart/lung diseases)
thick blood vs thin blood
thick blood: polycythaemia, high bp, more platelets lead to clots
thin blood: anaemia, less platelets, more bruising
