19.3 RBCs Flashcards
hemoglobin (Hb)
% of RBC proteins
red pigment that binds and transports oxygen & CO2. Hb accounts for 95% of RBC’s intracellular proteins
RBC count
in males? females?
number of RBCs per microliter
males: 4.5-6.3 million RBCs
females: 4.2-5.5 million RBCs
blood of an average adult contains ___ RBCs
25 trillion
RBCs account for ___ of cells in the human body
1/3
rouleaux
stacks of red blood cells formed in narrow blood vessels
RBC diameter
7.8 micrometers
RBC thickness
2.85 micrometers
center narrows to .8 micrometers
lifespan of RBC
<120 days
because RBC’s lack _____ & _____ they cannot divide or synthesize structural proteins
nuclei and ribosomes
RBCs also lack _____, so they obtain energy through anaerobic metabolism of glucose
mitochondria
nromal ranges of Hb content (males/females)
male: 14-18 g/dl
female: 12-16 g/dl
Hb structure
- quaternary
- 2 alpha chains, 2 beta chains
- each chain is a globular protein subunit and contains single molecule of heme
heme
non-protein pigment complex
-holds iron ion, interacts w/ oxygen to form oxyhemoglobin (HbO2)
oxyhemoglobin (HbO2)
hemoglobin molecule whose iron is bound to oxygen
-bright red
deoxyhemoglobin (HbO2)
hemoglobin molecule whose iron is not bound to oxygen
-dark red
fetal hemoglobin
binds to oxygen more readily, can “steal” oxygen from maternal bloodstream
hydroxyurea/butyrate
stimulate production of fetal hemoglobin in adults
each RBC contains ______ Hb molecules
280 million
carbaminohemoglobin
Hb bound to CO2
anemia
- results from low hematocrit, reduced Hb content of RBCs, or low RBC count
- interferes with oxygen delivery
- weakness, lethargy, confusion.. organ function deteriorates
RBC travels ____ miles in 120 days
700
% of RBCs replaced each day?
1%
how many new RBCs enter bloodstream each second?
3 million
hemoglobinuria
red-brown urine resulting from large number of broken down RBCs
hematuia
presence of intact RBCs in urine
-result of kidney damage of damaged vessels along urinary tract
biliverdin
organic compound with green color.. result of heme unit being stripped of iron
bilirubin
converted from biliverdin
- orange-yellow pigment
- excreted in bile
- causes jaundice if not excreted properly
bilirubin gets converted to pigments _____ & _____, which are converted to _____ & _____ when exposed to oxygen
- urobilinogens & stercobilinogens
- urobilins (yellow) & stercobilins (brown)
transferrin
plasma protein that binds to iron in bloodstream
iron is stored in two protein-iron complexes:
ferritin & hemosiderin
only site of RBC production in adults
red bone marrow
erythropoiesis (occurs in what tissue?)
RBC formation.. occurs in myeloid tissue (red bone marrow)
myeloid tissue location
vertebrae, sternum, ribs, skull, scapulae, pelvis, and proximal limb bones
hematologists
blood specialists
hemocytoblasts
multipotent stem cells.. produce:
- myeloid stem cells (divide into RBCs and several classes of WBCs)
- lymphoid stem cells (divide into various lymphocytes)
stages of RBC maturation
1) proerythroblast, 2) basophilic erythroblast, 3) polychromatophilic erythroblast 4) normoblast, 5-7) reticulocyte
- ->mature RBC
reticulocytes make up __% of RBC population in blood
0.8%
erythropoiesis requires adequate supplies of (three things)
amino acids, iron, & vitamins (B12, B6, & folic acid)
in order to absorb vitamin B12, we need
intrinsic factor (produced in stomach)
causes of pernicious anemia
possible causes: B12 deficiency, problem with intrinsic factor production, or problem with absorption of B12 bound to intrinsic factor
erythropoiesis is indirectly stimulated by
T4, androgens, and GH
hypoxia
low oxygen levels in tissues
EPO 2 major effects:
1) stimulates cell division rates in erythroblassts and in stem cells that produce erythroblasts, 2) speeds up RBC maturation by accelerating Hb synthesis
blood doping & EPO administration
can raise hematocrit to 65+, placing intolerable strain on the heart
elevated hematocrit (may reflect erythrocytosis or leukocytosis)
polycythemia
Reticulocyte count (retic.) is elevated
reticulocytosis
elevated RBC count
erythrocytosis/polycythemia
MCV (mean corpuscular volume)
(normal = 82-101 cubic micrometers)
elevated: macrocytic
depressed: microcytic
MCHC (mean corpuscular hemoglobin concentration)
(normal = 27-34 pg/microliter)
elevated: hyperchromic
depressed: hypochromic