Lecture 19: Peripheral Blood and Hematopoeisis Flashcards
what is peripheral blood “circulating blood”
blood that is not in bone marrow or other sites or hematopoiesis nor in lymphatic organs
**within a CLOSED circulation system
Functions of Peripheral Blood
- transport (nutrients, waste, cells, etc)
- coagulation
- thermoregulation
- acid base balance (buffer)
- osmotic balance (pressure)
what is peripheral blood composed of
specialized CT
cells (formed elements)
plasma (ECM)
what are the formed elements of peripheral blood
Erythrocytes (RBCs) : gas transport (O2, CO2)
Leukocytes (WBCs) : host defense
Platelets : coagulation
what stain is used in a peripheral blood stain
Romanovsky stains: Eoisin and methylene blue
what is the purpose of the biconcave disk shape of erythrocytes?
it maximizes cell surface area and maneuverability through small blood vessels
how are erythrocytes (RBCs) formed?
via erythropoiesis
what cell type makes up a majority (40-45%) of total blood volume
erythrocytes (RBCs)
characteristics of RBCs
- no organelles
- no nucleus
- lots of hemoglobin
Erythropoiesis basics
- 7 days
- happens in bone marrow
- stimulated by hypoxia
term for immature RBCs and why would they enter into circulation prematurely
immature RBCs = RETICULOCYTES
- enter into circulation prematurely if there is great blood loss
( in humans in carnivores )
What is the function of leukocytes and where do they carry it out
function in the CT extracellular (interstitial spaces) even though they are transported in the peripheral blood
- function = host defense
lifetime of WBCs?
short-lived (hours/days)
- die via apoptosis & cleaned up by macrophages
What are the 2 types of Leukocytes?
WBCs are differentiated based on the presence or absence of certain granules in their cytoplasm
Granulocytes & Agranulocytes
What are the 3 granulocytes?
neutrophils, eosinophils (pink), basophils (purple)
- have lobulated nuclei
- have specific granules
- poorly developed rER and golgi
- few mitochondria
- short lived
what are the 2 types of agranulocytes?
Lymphocytes (B&T) and monocytes
- no specific granules
- round/indented nuclei
What are the granules that all granulocytes have
primary granules = lysosomes (azurophilic granules)
secondary granules = enzymes w/ specific functions
what is the most numerous WBC and what is its function
Neutrophils (60-70% of WBC count)
function: phagocytosis and destroying bacteria, they release cytokines
- multilobed nuclei
- cytoplasm is pale - neutral
- utilize glucogen
- major component of pus (pus=exploded neutrophils)
what is the purpose of neutrophils releasing cytokines?
cytokines recruit more leukocytes & promote inflammation and fever (pyrogenic)
function and characteristics of eosinophils
<4% of WBC count
function: parasite destruction
- bilobed nucleus
- pink cytoplasm
- specific granules
- major basic protein (MBP) is antiparasitic
- cat’s eye appearance at TEM
function and characteristics of basophils
<1% of WBC count
function: initiate inflammatory response & hypersensitivity reactions
- odd shaped nucleus usually obscured
- purple cytoplasm
- specific granules
- heparin, histamine
similar structure / function as mast cells
function and characteristics of Agranular leukocytes
different from granulocytes in that..
- no specific granules
- long-lived
- non-lobed nuclei
function and characteristics of Agranular Lymphocytes
2nd most numerous WBC (20-25%)
function: immunity
- nucleus is round and large
- light blue cytoplasm (thin b/c nuc so big)
- lots of free ribosomes
**only WBC that return to blood after being in CT or a lymphatic organ
what is the only WBC that returns to blood after being in CT or a lymphatic organ
agranular lymphocytes
function and characteristics of Monocytes
largest WBC
function: become macrophages
- pale/gray cytoplasm
- bean/oval shaped nucleus
- golgi, lysosomes, mitochondria
Platelets (Thrombocytes)
<0.2% of total blood volume
function: limit hemorrhage
- anucleate
- dark cytoplasm
- short lived, removed by macrophages
- have demarcation channels
Where do Platelets (Thrombocytes) originate from
come from megakaryoctyes in bone marrow
- a single megakaryocyte can shed 5-10,000 platelets
what are the demarcation channels that platelets have
invaginations of the plasma membrane that separate cytoplasmic fragments into proplatelets that ‘break off’ to form platelets
what hematological problem is this
polycythemia (too many RBC)
what hematological problem is this
anemia
what hematological problem is this
leukocytosis - WBC explosions
what is this
eosinophil
- bilobed nucleus
- pink cytoplasm
- anti-parasitic SGs
what is this
Basophil
- odd shaped nucleus
- purple cytoplasm
- inflammations SGs
what is this
neutrophil
- multilobed nucleus
- pale cytoplasm
- antibacterial SGs
