6.5 Blood Flashcards
What are the components of blood?
Plasma
Formed elements: RBC, WBC, platelets
What is plasma composed of?
90% water
6-8% protein: albumin, globulins, fibrinogen
1% electrolytes: Na+, Cl-, HCO3-, K+, Ca2+
nutrients: glucose, amino acids, vitamins, lipids
waste: urea, creatinine, bilirubin
dissolved gases: O2, CO2
hormones: steroid and thyroid hormones carried by plasma proteins
How does plasma act as a buffer?
because plasma is 90% water, it acts as a pH buffer, resisting changes in pH
How does plasma maintain osmotic balance?
ater, electrolyte, protein content balanced to maintain osmotic gradients
What are the plasma proteins? Which is most common?
Albumin protein: carrier maintains osmotic balance between blood and ECF Globulin proteins: carriers form antibodies (made by WBC’s) Fibrinogen: blood clotting
What is the structure of an RBC?
biconcave, “donut” shape flattened small size (7.5 μm diameter) no nucleus, few organelles (no mitochondria) structural proteins 97% hemoglobin protein
What makes hemoglobin?
4 subunits:
2 A, 2 B
4 Fe molecules
How many oxygen molecules can each HgB carry?
4
Where are old RBCs degraded? How?
By macrophages in spleen, liver, red marrow
What happens to heme, iron, and the globin in HgB?
Heme–> bilirubin, sent to liver to be excreted as bile
Iron- taken up by macrophages for reuse
Globin- broken to AAs and recycled
What causes jaundice?
Bilirubin build up
What causes Hyperbilirubinemia?
Increased breakdown of RBCs
Decreased elimination of bilirubin by liver
What is hematopoiesis?
blood cell formation from stem cells in the red bone marrow
Where does erythropoiesis occur? What hormone stimulates it? Describe the process
occurs in Red Bone Marrow: sternum, ribs, pelvis, long bones
requires hormone: erythropoieitin (EPO)
stimulus: low O2
kidneys release EPO
effector: red bone marrow
response: increased erythropoiesis, make more RBC’s
Stem cells make more stem cells which make RBCs, WBCs, platelets
Reticulocyte- precursor cell to RBCs, can measure reticulocyte to see if problem with maturation of RBCs
What are the stimulus, receptor, control center, effector and response of erythropoiesis regulation?
stimulus: low O2 in blood
receptor: kidney cells, increased hypoxia inducing factor (HIF)
control center: kidneys increase erythropoietin (EPO)
effector: red bone marrow
response: make more RBC’s
Why are B12 and folate important for RBC production?
necessary for DNA synthesis and stem cell division
** including Hematopoeitic stem cells
Very sensitive, even slight changes in B12 and Folic acid levels affect production
Some anemias are from low B12 levels
Where is iron absorbed, carried, and stored?
Absorbed by small intestine
recycled after RBC breakdown
carried through bloodstream to bone marrow by transferrin protein
carried to the liver for storage as ferritin
What is anemia? What are common causes
Anemia occurs when blood oxygen carrying capacity is too low Many causes: Blood Loss trauma bleeding Low RBC production iron deficiency B12 deficiency EPO deficiency red bone marrow damage High RBC breakdown genetic diseases (sickle cell anemia, thalassemia’s)
What are the 5 types of WBCs?
Neutrophils Lymphocytes(B-lymphocytes, T-lymphocytes) Monocytes Eosinophils Basophils
What are the function of neutrophils? Prevalence
(50-70%): phagocytes, first response to infection, stress, inflammation
engulf and destroy bacteria using lysosomal enzymes in granules
release free radicals
What is the function of lymphocytes? Prevalence?
25%) form adaptive immunity
B-cells: produce antibodies against foreign cells or viruses
T-cells: kill infected cells, cancerous cells
What is the function of monocytes?
Become macrophages
phagocytes, inflammation, antigen response
engulf and destroy pathogens, debris
What is the function of eosinophils? Prevalence?
(2-4%): allergic reaction and parasite defense
release chemical mediators and enzymes: histamine, nucleases, lipase, plasminogen in granules
What is the function of basophils, prevalence?
(0.5 -1%): inflammation, allergy and parasite defense
histamine, prostaglandins, leukotrienes, heparin in granules
