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blood functions
- 1. transportation of gases, nutrients & hormones
- 2. regulation of pH, body temp
- 3. protection through clotting, WBC
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blood components
- blood plasma (extracellular matrix): 91.5% water, 8.5% solutes (mostly hemoglobin and also hepatocytes which synth proteins)
- formed elements: RBC, WBC, Platelets
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blood cell formation
- red bone marrow is primary site
- Negative feedback regulates # of RBCS and platelets
- makes WBC in response to pathogens
- pluripotent stem cells can develop into many different types of cells
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Red Bone Marrow role
- primary site of blood cell formation
- made of yellow fat cells
- the RBCs that are here are immature and have nucleus to divide. Once mature, they lose nucleus to make way for more hemoglobins to carry oxygen
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Do elements divide once they leave bone marrow
No, except for lymphocytes
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What do stem cells produce
- 1. myeloid cells: give rise to RBC, platelets, monocytes, neutrophils, basophils, eosinophils
- 2. Lymphoid cells: give rise to lymphocytes
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RBCs
- contain hemoglobin
- donut shaped w/strong plasma membrane
- glycolipids in membrane responsible for ABO & Rh types
- lack nucleus & other organelles such as mitochondria
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Hemoglobin
- 4 polypeptide chains w/4 hemes attached
- transports 23% of total CO2
- NOxide binds to hemoglobin, releasing NO causing vasodilation..improving blood flow and oxygen delivery
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RBC lifecycle
- 120 days
- destroyed RBCs removed by macrophages in spleen & liver
- Globin, Iron are reused
- Heme ends up in urine or feces
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Erythropoiesis
- Process by which RBC's are produced
- starts in red bone marrow with proerythroblast
- negative feedback balances this
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hypoxia
when tissues are NOT receiving enough O2. This causes the release of erythropoietin to MAKE more RBC's
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WBCs
- have Nuclei, NO hemoglobin
- two types:
- granular: neutro, baso, eosinophils
- Agranular: lymphocytes & monocytes
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leukocytosis
a protective response from foreign substances
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Leukopenia
DECREASE in WBC's :(
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WBC's lifespan
- generally live for a few days
- EXCEPT lymphocytes, which can live for years!
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WBC fxn when pathogen present
WBC's leave the bloodstream and squeeze b/w ENDOTHELIAL cells
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neutrophils
- use LYSOZYMES to kill bacteria
- Small in #, but act QUICKLY
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monocytes
- differentiate into macrophages to destroy microbes
- large in #'s, but take LONGer to arrive
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basophils
- release heparin, histamine, seratonin
- intensify inflammatory reaction
- ie: antihistamine
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eosinophils
releases enzymes (histaminase) which attack parasites
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lymphocytes components
- B-cells: destroy bacteria & toxins
- T-cells: attack viruses, fungi, cancer & some bac
- NK cells: attack wide variety of microbes
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Platelets/Thrombocytes
- Myeloid stem cells develop into MEGAkaryocytes
- help stop blood loss by clotting
- disc shaped, NO nucleus, short lifespan
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STEM cell transplants (2 types)
- Bone marrow: replaces bone marrow with healthy individual, taking 2-3 weeks for enough WBC's to be produced
- Cord-blood: stem cells taken from umbilical cord before birth, can be stored indefinitely
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Bone marrow transplant risks
Graft-vs HOST disease: the red bone marrow transplanted produces T-cells that attack host tissues
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Hemostasis
- A sequence of 3 things that occur to STOP bleeding
- 1. vascular spasm: smooth muscles in artery CONTRACT
- 2. platelet PLUG formation: platelets accumulate in large #'s
- 3. blood clotting
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Blood Groups: ABO
- ABO
- ABO: if have type A blood, you have the A antigen (and B antibodies, so NO B antigen)
- O is universal donor, AB is universal ACCEPTOR (has neither antibodies so does not agglutinate
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Rh and Hemolytic disease
Occurs when Rh- mother (w/out Rh antigen) has a Rh+ child. This results in Rh antibodies in mother, which can affect a 2nd child who is Rh+ (mom's antibodies will attack antigen)
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