Heme structure & function Flashcards
functions of blood
- transport of:
- ->metabolic components, nutrients, hormones
- gas exchange
- immune defense
- coagulation
WHOLE BLOOD b/d:
-whats in it
plasma 55%
- ->proteins–albumins, globulins, fibrinogen, prothrombin
- ->water (91%)
- ->other solutes–ions, nutrients, waste products, gases, regulatory processes
formed elements 45%
- ->platlets
- ->leukocytes–neutrophils, lymphocytes, monocytes, eosinophils, basophils
- ->erythrocytes= >99% of formed elements
in a centrifuged sample of blood, what is the layer order
plasma on top
buffy coat
formed elements on bottom
what is plasma mainly consisted of
water
serum vs plasma
serum=plasma thats been allowed to clot in the lab in order to remove fibrinogen and other clotting factors that can interact with diagnostic testing
what contains clotting factors
plasma
most plasma proteins are produced by ?
-except for?
liver
EXCEPT for immunoglobulins aka antibodies-
what produces antibodies
plasma cells in lymph nodes
total blood volume in adult
5.5 L
plasma contains two major groups of plasma proteins
- albumins
2. globulins
list the cellular elements of blood
RBCS (erythryocytes)
WBCS (leukocytes)
Platelets (thrombocytes)
role of erythrocytes
tissue oxygenation
what is the most abundant cells in blood
erythrocytes
erythrocyte structure, life span, what removes old rbcs?
inside=hemoglobin
- mature rbc lacks nucleus and cytoplasmic organelles
- limited life span=100-120 days
- spleen removes RBCs from circulation
role of hemoglobin
carries the gases, electrolytes that regulate diffusion thru cell plasma membrane
role of leukocytes
-categories?
- defend the body against infection
- remove dead or injured host cells
- granulocytes–neutrophils, basophils and eosinophils—all PHAGOCYTES
- agranulocytes
- ->monocytes, macrophages–PHAGOCYTES
- ->lymphocytes—IMMUNOCYTES
role of thrombocytes
blood coagulation
control bleeding
**technically not true cells—they are irregularly shaped cytoplasmic fragements
basic roles of the lymphoid organs
provide sites of:
-residence, proliferation, differentiation or function of lymphocytes and mononuclear phagocytes
largest lymphoid organ
spleen
role of spleen (3)
- functions as site of fetal hematopoiesis
- filters and cleanses the blood
- acts as a resevoir for lymphoctes and other blood cells
list the primary lymphoid organs
thymus
bone marrow
secondary lymphoid organs
spleen
lymph nodes
tonsils
Peyer patches in ileum of small intest
lymph nodes role
-site of development or activity of large number of lymphoctes, monocytes and macrophages
red marrow consists of?
-also called
red aka active or hematopoietic marrow
-also called myeloid tissue
yellow marrow consits of
inactive marrow
where are stem cells found
bone marrow
two most common stem cell populations
- hematopoietic stem cells
2. mesenchmal stem cells
Hematopoietic stem cells
- what are they
- what do they develop into?
progenitors of all hematologic cells
-develop into: blood cells (RBC + WBC + Plats) and osteoclasts
mesenchymal stem cells are?
- role?
- what can they differentiate into?
stromal cells and have a role in maintaining hematopoietic stem cells
-can differentiate into: osteoblasts, adipocytes, chondrocytes
what do osteoblasts and osteoclasts produce?
cytokines
what do cytokines do
proliferate and maintain hematopoietic cells
Myelopoiesis
-define
is the development of GRANULOCYTES (BEN) and monocytes from the differentiate of myeloid progenitor cells in bone marrow
what are the granuloctes and monocytes generated from
Myeloid progenitor cells
lymphocytes are generated from
-what is this process called
lymphoid progenitor cells–>lymphopoiesis
what are platelets derived from and what is the process called
megakaryocytes
process is called thrombopoiesis
what controls thrombopoiesis
thrombopoietin
what do megakaryocytes under during thrombopoiesis
mitosis— but NOT cell division
-cytoplasm and plasm membrane fragment into the platelets
lymphoid progenitor cells differentiate into?
- B cells
- T cells
- NK cells
megakaryocytes differentiate into?
thrombocytes
reticulocytes differentiate into?
erythryocytes
myeloblasts differentiate into?
basophils eosinophils neutrophils (granuloytes)
monocytes—-which then differenatie into dendritic cells and macrophages
colony stimulating factors
- specific hematopoietic growth factors
- needed for prod of myeloid, erythroid, lymphoid and megakaryocytic lineages
where does hematopoiesis occur
- fetus
- after birth
liver
spleen
of the fetus
bone marrow after birth
regulation of erythropoiesis mediated by
erythropoietin
where is erythropoietin secreted and in resp to what
kidneys and in response to tissue hypoxia
erythropoietin (EPO) causes?
compensatory increase in erythryocyte production if oxygen content of blood decreases (anemia, high altitude, pulm dz, etc)
erythropoesis define
development of RBC
erythropoiesis depends on?
vitamin B12 ***
folate ****
B6
riboflavin
niacin
iron binds to ____ in the blood
transferrin
iron is transported to ____ after binding to transferring
macrophages
where is iron stored and as what
stored in cytoplasm as ferritin
describe the steps of iron cycle
-
reutilizes iron released from old or damaged erythrocytes
1. iron binds to transferrin in blod
2. transported to macrophages
3. stored in cytoplasm as ferritin
iron homeostasis is controlled by
hepcidin
what is hepcidin and its role
-where is it produced
small hormone—regulates ferroportin–principal transport for iron from stores in hepatocytes + macrophages (in spleen + intestines)
its prod by hepatocytes
ferroportin role
transmembrane protein— transports the stored iron from hepatocytes, macrophages in spleen/intestines
hemostasis define
arrest of bleeding
two pathways involved w/ hemostasis
PRIMARY HEMOSTASIS
- vasoconstriction
- formation of platelet plug
SECONDARY HEMOSTASIS
- activation of the clotting/coag cascade
- formation of a fibrin bloood clot
basic steps/process for hemostasis
- injury/rupture of BV
- BV around wound constricts—-this reduces blood flow to the damaged area
- activated platelets stick to injury site
- plats become sticky and clump together to form platelet plug
- plats and damaged tissue release clotting factors
- blood clotting mechanism to form Fibrin—–acts like a mesh to stop bleeding
what factors involved with intrinsic pathway
-blood test?
XII XI X IX VIII TEST=aPTT---activated partial thromboplastin time
factors involved for extrinsic pathway
-blood test?
VII
X
TEST=prothrombin time PT
common pathway steps
Prothrombin II + thrombin–>fibrinogen I–>fibrin clot
Fibrinolysis define
ex
enzymatic b/d of the fibrin in blood clots
-process tht prevents blood clots from growing and become problematic
**clot retraction + clot dissolution
EX: TPA
what enzyme is responsible for fibrinolysis
plasmin—splits fibrin and fibrinogen into fibring degradation products that dissolve the clots
life span of RBC
120 days
structure of RBC
-what can affect their strucutre
- disc shape, uniform in size and shape
- inside=hemoglobin
- **B12 deficiency, folate deficiency and iron deficiency can affect their appereance
what is hemoglobin
protein that transport oxygen
infections stimulate _____ to produce a higher number of _____
bone marrow to produce neutrophils
what WBC is incr with allergies
eosinohpils
thrombocytopenia
low platelets
excessive bleeding and bruising
thrombocytopenia
thrombocytosis
too many platelets
what is evaluated in CBC lab test
all the cells that circulate in the blood:
- RBCs
- WBCs
- Plats
anemia
low RBC count
RBC count?
actual number of RBCs in blood sample
hemoglobin lab test
total amount of oxygen-carrying protein in the blood—generally reflects number of RBCs in blood
Hematocrit
measure percentage of total blood volume that consists of RBCs
RBC indicies?
provide information on the physical features of the RBCs
Mean Corpuscular Volume (MCV)
measurement of the avg size of RBCs
Mean corpuscular hemoglobin (MCH)
calculated measurement of the avg AMOUNT of hemoglobin inside your RBCs
mean corpuscular hemoglobin concentration (MCHC)
calculated measurement of the avg CONCENTRATION of hgb inside RBCs
Red Cell distribution width (RDW)
measurement of the variation in size of RBCs
Reticulocyte count
measurement of the absolute count or pervent of newly released young RBCs
WBC differential
can be added if WBC count is too low or high
-differential IDs and counts number of the five types of WBCs present
Mean platelet volume
can be indicated in a CBC or not
-measurement of avg size of plats
platelet distribution width (PDW)
can be included in a CBC or not
-reflects how uniform plats are in size
immature granulocytes
- what is it
- what does it indicate
WBCs that havent fully developed b4 being releasd from bone marrow into cirulation
- only present in bone marrow (NOT in circulating blood)
- can indicate an infection or blood CA
Reticulocyte Hemoglobin
measures hgb present inside of reticulocytes
-often reported as a Mean reticulocyte hemoglobin content or a reticulocyte hemoglobin equivalnt
blood smear
- done when
- wht does it do
as a follow up to abnormal results on an automated CBC
compares WBC size, shape and general apperance to normal WBCs
RBC morphology=evals size, shape and color—-indicator of hgb content
