Lecture 5 - Blood and Bone Marrow Flashcards
Blood - what is it, what is equivalent to ground substance, solubility and what happens with clotting, how do you view blood cells and stains
-a specialized CT consisting of blood & immune system cells suspended in plasma
-plasma is tissue fluid equivalent to ground substance minus fibers
-fibres of blood are soluble; the proteins become fibrous upon activation of coagulation (clotting)
Blood cells viewed via cell smears
-special stain: (Wright’s) eosin + 2 different basic dyes
-basophilic substances still blue
even though hematoxylin not used
what are the three components of blood and what is included in each
- plasma - water(92%), proteins (7% by weight, albumin biggest part), other solutes
-erythrocytes
-buffy coat - platelets, leukocytes (neutrophils, lymphocytes, monocytes, basophils, eosinophils)
components of blood - formed elements and leukocytes - what are they, what are their features
“Formed Elements” = Erythrocytes & platelets (thrombocytes)
* no nuclei*
* “fragments” of cells
Leukocytes (white blood cells)
-Granulocytes:
* nucleated blood cells with specific granules or storage vesicles
-Agranulocytes:
* nucleated blood cells without “specific” granules
erythrocytes - what else are they called, what are they involved in, how abundant, staining, % hemoglobin, where is it present
- also called red blood “cells” (RBCs)
- involved in O 2 /CO 2 exchange and blood pH balance
- most abundant “formed element” in blood (~40% of volume)
- homogeneous eosinophilic cytoplasm – 30% hemoglobin
- present in most tissue sections; internal scale bar (7-8 μm)
erythrocyte morphology and staining
- anuclear bi-concave discs for maximum surface area
- very eosinophilic due to high hemoglobin (protein) content (NOT due to presence of
iron!)
leukocytes - what do they look like, what arent they involved in, what is their function, what are they associated with
- nucleated cells of blood are larger than erythrocytes
- not really involved in functionality of blood directly
- travelling from site to site & surveillance
- associated with responses to tissue damage, infection, immunity
blood and immune system cells - what do they come from, what does it give rise to, daughter cells, what happens when they go from bone marrow to the blood stream
- all blood and immune system cells come from a common stem cell precursor in the bone marrow
- common precursor gives rise to stem cells for erythrocytes and platelets, and for leukocytes
- these stem cells give rise to lineage specific progenitors
- daughter cells differentiate mostly in the bone marrow into the functionally different cell types
From the bone marrow, cells enter the blood stream and:
* stay in blood and act in blood
* travel via blood & exit into loose CT all over the body (transient CT cells)
* transient cells may re-enter circulation or remain in tissue
what cells are present in blood vs CT vs both
Blood - erythrocytes, platelets, monocytes, basophils
CT - marcophage, plasma cell (from B lymphocyte)
Both - lymphocytes, eosinophil, neutrophil
granulocytic leukocytes - what in included in this classifications, common features, unique features
-eosinophils, basophils, neutrophils
common features:
* derived from common bone marrow precursor
* multilobed nucleus
* auzurophilic granules (1o granules; lysosomes)
unique features:
* specific granules (2o granules)
* unique functionality for each cell type
Neutrophils (PMNs) - abundance, appearance and staining, function, how its seen in TEM
- most abundant granulocyte in blood
- multi-lobed nucleus; immature version has band-like nucleus
- pale, poorly stained cytoplasm
- specific granules not abundant or large, so best seen in TEM
- usually first immune cells to enter site of inflammation/infection; kill microorganisms by phagocytosis and secretion of antibacterial enzymes/peptides/ROS
eosinophils - size, appearance, what do they granules contain, function
- mid-sized & fairly abundant leukocyte in blood
- large bi-lobed (occasionally tri lobed) nucleus
- pale, poorly stained cytoplasm; large prominent eosinophilic specific granules
- granules contain rod-shaped inclusions visible in TEM
- kill endo-parasites (e.g. round worms, flukes, etc.) & modulate basophil and mast cell activity
basophils - how common, appearance, granule stain
- very rare; < 0.5% of all leukocytes
- large tri-lobed nucleus
- pale, poorly stained cytoplasm
- large deeply stained basophilic granules; may obscure nucleus
- granules stain metachromatic (cause color shift) with Toluidine Blue
basophil functions - where are cells release from and what is done, what does degranulation cause, mast cells
- cells released from bone marrow & circulate for short time
- modulate allergic reactions:
immediate reaction to second
stimulus by an antigen (via IgE) - degranulation causes vasodilation, edema, mucus
secretion, bronchiole constriction - can be life threatening: systemic
- Mast Cells are related cell type found in tissue- usually more localized response but can also
be systemic response
agranulocytic leukocytes - what cell types are included, how is it directly related to immune responses, general features
-lymphocytes, monocytes
-Directly related to immune responses:
- humoral immunity (lymphocytes)
- intrinsic immunity (monocyte/macrophage)
-General Features:
- no obvious specific granules
- azurophilic granules (lysosomes) as all leukocytes do; may or may not be obvious in LM
- nucleus not multilobed
- relatively sparse cytoplasm
lymphocytes - size, appearance, what is prominent and what does it look like
- smallest nucleated cell in blood; often not much larger than RBC
- very little cytoplasm; cytoplasm usually basophilic
- nucleus with dense heterochromatin; nucleus is often only prominent feature, especially in tissue sections