blood Flashcards
how much of BW is blood
7-8%
how much of blood is plasma
45-65%
is plasma acidic or alkaline
alkaline
what does plasma consist of
dissolved gases, electrolytes, proteins, CHOs, lipids, hormones
red blood cells proper name
erythrocytes
white blood cells proper name
leukocytes
platelets proper name
thrombocytes
erythrocytes are highly specialized in that they contain
hemoglobin
hemoglobin in erythrocytes function
carries O2 and CO2, maintains shape of erythrocytes
what do erythrocytes look like in mammals
round, biconcave, anucleate
erythrocytes cytoplasm
acidophilic
60% water
40% solid (Hb)
life span of erythrocytes
120 days
what is the most numerous blood cell
erythrocytes (RBCs)
is birds and reptiles erythrocytes are
nucleated
erythrocytes are released into circulation as an immature form called
reticulocyte
reticulocyte
immature erythrocyte, slightly larger
leukocytes are responsible for
bodys immune response
clinical significance of number of leukocytes in blood
infection/ inflammation
they migrate to other tissues so numbers in blood is variable
2 groups of leukocytes
granular leukocytes (basophils (blue), neutrophils (white) and eosinophils (red) )
non-granular leukocytes (lymphocytes and monocytes)
what is the most numerous of granulocytes (granular leukocytes)
neutrophils
(in carnivores most numerous of all leukocytes)
why are neutrophils ‘white”
light staining granules that are usually not visible
describe neutrophil nucelus
multi-lobed when mature;
U or S shaped in immature cells
barr bodies
inactive X chromosome in females, seen as a little dot on the nucleus of neutrophils
neutrophils function
- Phagocytose bacteria & other particulate material
- degraded by enzymes contained within the granules
- Mobilised in large numbers to focus of infection
main constituent of pus
neutrophils
how many days are neutrophils in circulation
5 days
eosinophils are slightly ____ than nuetrophils
larger
why are eosinophils ‘red’
large acidophilic granules that stain red
eosinophil nucleus
bilobed
what do granules in eosinophils contain
hydrolytic enzymes & peroxidases
functions of eosinophils
- phagocytose antigen/antibody complexes
- kill helminth parasites
- rest against invading worms & release
contents of granules onto them - Implicated in hypersensitivity reactions
- a blood smear from an animal with flea allergy dermatitis
will show an eosinophilia
basophils frequency
rare
basophils are precursors to
tissue mast cells
why are basophils ‘blue’
many large darkly basophilic granules
basophil granules contain
histamine, heparin and serotonin
basophil nucleus
bilobed nucleus often obscured by granules
basophil functions
- In addition to eosinophils, involved in response to helminth parasites
- Appear to play an important role in the activation of a subset of T lymphocytes
- Implicated in hypersensitivity reactions such as asthma, hayfever, & anaphylactic shock
lymphocytes found in
circulation in blood and lymph
lymphocytes are concentrated in lymphoid tissue such as
lymph nodes, nodules, spleen and peyer’s patches in intestine
after neutrophils, what is the 2nd most abundant leukocyte in blood
lymphocytes
lymphocyte nucleus
oval/ kidney shaped
two forms of lymphocytes
small; most
large
what is the body’s immunological defense system
lymphocytes
3 classes of lymphocytes
T cells, B cells, natural killer cells
T cells
- responsible for cell-mediated immune response
- release granules that kill virus-infected & tumour cells
- small lymphocytes
B cells
- produce antibodies (humoral immune response)
- subset of B cells are plasma cells
- small lymphocytes
Natural killer cells
- cell-mediated immune response
- release granules that kill virus-infected and tumour cells
- large lymphocytes
monocytes frequency
around 5% of leukocytes
what is the largest leukocyte
monocytes
monocyte nucleus
Large, eccentric nucleus that is relatively pale-staining
Nuclear shape is variable: often indented & becomes
more horseshoe-shaped as cell matures
May have 2 or more nucleoli
monocyte function
- Have little function in circulating blood
- Highly motile and phagocytic
- Leave the blood after about 3 days & enter tissues:
- macrophages (free roaming within tissue)
- histiocytes (fixed within tissue)
- Respond to: necrotic tissue, microorganisms, inflammation
- Present with neutrophils in pus
- Multinucleate giant cells form by fusion of macrophages
- reminiscent of osteoclasts
thrombocytes are not
whole cells; cytoplasmic fragments of a large cell; megakaryocyte
thrombocytes size
very small
what do thrombocytes assist in
formation of blood clots (thrombi)
how do thrombocytes appear on blood smears
in clumps
thrombocytes contain granules that store factors associated w
coagulation, inflammation, immune function
thrombocytes respond to damaged endothelium in 2 stages;
- Aggregate to form an immediate plug, temporarily stops haemorrhage
- Catalyse the formation of fibrin clot, forms a more permanent seal
production of new blood cells is called
haematopoiesis
where does haematopoiesis occur (production of new blood cells)
- bone marrow
- lymphatic organs (ex spleen)
- liver of fetus and young
____ cells serve as origin for each line of blood cells
stem
haemoatopoiesis of erythrocytes
- Erythropoiesis
- Derived from myeloid stem cells in the bone marrow, which
give rise to a large nucleated cell: proerythroblast - Nucleus undergoes chromatin condensation & is extruded
- Enter circulation as reticulocytes
- Remnants of rRNA in cytoplasm
- Severe haemorrhage/haemolysis
- erythrocyte production increases
- proportion of reticulocytes in circulation
increases (reticulocytosis)
lymph consists of
- Excess interstitial fluid
- Ions – similar concentrations to plasma
- Proteins – lower concentrations than plasma
- large proteins don’t leave capillaries
- Cells – lymphocytes, macrophages
- Foreign matter – microbes, proteins
- Lipids from digestion; lipid molecules that are too big to enter circulatory system enter via the lymphatic system
- lacteals in the intestinal villi
describe how blood leaves the heart
Blood leaves the heart and travels to tissues via
vessels of diminishing size:
* elastic arteries (e.g. aorta)
* muscular arteries
* arterioles
* capillaries and sinusoids
venules collect blood from
capillaries
* medium veins
* large veins return blood to the heart
(e.g. vena cava)
elastic arteries
- large vessels
- transport blood from the heart
- walls contain large proportion of elastic fibres
- stretch & recoil as blood pumped
- limited amounts of smooth muscle
muscular arteries
- large amounts of smooth muscle
- reduced elastic tissue
arterioles
- much smaller than muscular arteries
- 1-2 layers of smooth muscle only
capillaries and sinusoids
- thin walled: endothelium on a basement membrane
- sinusoids are wider in diameter than capillaries
- areas where there is a high exchange of solutes
venules
- small venules resemble capillaries, but more expanded
- larger venules contain a layer of smooth muscle
medium veins
- comparable in size to muscular arteries, but muscle layer is much thinner
large veins
- thicker wall and larger lumen, but similar structure
valves
- occur in many veins where diameter >2mm
- free edges flow in direction of blood
- prevent back-flow
Differentiating Arteries from Veins
- Arteries & veins which supply the same tissue are usually
side by side - Artery walls are thicker; more smooth muscle & elastic fibres
- Artery walls remain circular, veins collapse
- Elastic fibres recoil
- constrict lumen of arteries
- Arterial endothelium folded; smooth in veins
lymph vessels
- Vessels of varying size
- lymphatic capillaries
- lymphatic vessels –> major lymph trunks
*Structure is similar to blood vessels:
* single layer of endothelial cells
* collagen & elastin fibres in larger vessels
* smooth muscle also present in larger vessels
*Permeable, blind-ending
* Branch & anastomose
* form a network within connective tissue
* Close to capillaries & venules
lymph vessels ___ in size as they approach thorax
increase
where are lymph vessels smallest
in peripheral tissues
flow of lymph (unidirectional)
blind-ending lymphatic capillaries
–>
afferent lymphatic vessels
–>
lymph node
–>
efferent lymphatic vessels
–>
major lymph trunk
–>
large vein in the neck
