Blood + Physiology Flashcards
Blood makes up __% of body weight in mammals
7-8%
45-65% of blood volume is made of
Plasma (mostly water)
Plasma is __ and contains (6)
-alkaline
-dissolved gases, electrolytes, proteins, CHOs, lipids, and hormones
~45% of blood is made of
Formed elements (erthyrocytes, leukocytes, and thrombocytes)
Erythrocytes (3)
-highly specialized in that they contain haemoglobin
-round, biconcave, lack a nucleus (in mammals), relatively small
-plastic, can conform to narrow vessels
Erythrocytes are also called
Red blood cells
Haemoglobin (3)
-found in RBCs
-carries oxygen and carbon dioxide
-helps maintain the shape of RBCs
White blood cells are also called
Leukocytes
RBCs have a life span of
120 days
Platelets are also called
Thrombocytes
In birds and reptiles, the erythrocyte is
Nucleated
The most numerous blood cell in the body are
RBCs
RBCs have an ___ cytoplasm which stains ___ and is composed of
-acidophilic (stains purple)
-60% water and 40% solid (Haemoglobin)
Reticulocyte (4)
-immature RBC
-slightly larger
-methylene blue staining as there are rRNA remnant
-proportion is clinically significant
Leukocytes are responsible for
The body’s immune response
Two groups of leukocytes
-granular
-non-granular
5 types of leukocytes (from most abundant in body to least)
-Neutrophils
-Lymphocytes
-Monocytes
-Eosinophils
-Basophils
3 types of granular leukocytes
-neutrophils
-eosinophils
-basophils
2 types of non-granular leukocytes
-lymphocytes
-monocytes
Main component of pus are
Neutrophils
Neutrophils (7)
-most numerous granulocyte
-most numerous leukocyte in carnivores
-large
-lightly staining granules
-multilobed when mature
-U or S shaped when immature
-proportion of mature to immature cells is clinically important
Band neutrophils are
Immature neutrophils that have a U or S shaped nucleus
A “left shift” means
There are more immature neutrophils than mature
Barr body
Neutrophils in females, inactive X chromosome
Neutrophils stay in circulation for
5 days
Function of neutrophils (3)
-phagocytose bacteria and other particulate material
-enzymes within granules degrade bacteria
-mobilize in large number to infection are
Eosinophils (5)
-relatively infrequent (2-8% of leukocytes)
-granular
-slightly larger than neutrophils
-large, acidophilic granules that stain red
-bilobed nucleus
Eosinophils granules contain
Hydrolytic enzymes and peroxidases
Function of eosinophils (3)
-phagocytose antigen/antibody complexes
-kill helminth parasites by resting against the worm and releasing granule contents onto them
-implicated in hypersensitivity reactions (ie. an animal with flea allergy dermatitis will show increase in eosinophils)
Basophils (5)
-rarely encountered (up to 1.5% of leukocytes)
-similar in size to eosinophils
-precursor to tissue mast cells
-large, darkly basophilic granules that appear blue
-bilobed nucleus but difficult to see because of granules
Basophil granules contain (3)
-histamine
-heparin
-serotonin
Basophil function (3)
-response to helminth parasites
-activation of a subset of T lymphocytes
-implicated in hypersensitivity reactions (ex. Asthma, hayfever, and anaphylactic shock)
The second most abundant leukocyte are
Lymphocytes
Two forms of lymphocytes
-small (97% of blood lymphocytes)
-large
Lymphocytes (4)
-found in blood and lymph circulation
-concentrated in lymphoid tissue (lymph nodes, nodules, spleen, and Peyer’s patches in intestine)
-ovoid to kidney-shape nucleus
-large nucleus compared to cytoplasm
Lymphocytes are the body’s
Immunological (cell mediated and humeral) defence system
3 classes of lymphocytes
-T cells
-B cells
-Natural Killer cells
T cells (3)
-small lymphocytes
-cell-mediated immune response
-release granules that kill virus-infected and tumour cells
A subset of B cells are
Plasma cells
B cells (3)
-small lymphocytes
-humoral immune response
-produce antibodies
Natural Killer Cells (3)
-large lymphocytes
-cell-mediated immune response
-release granules that kill virus infected and tumour cells
The largest leukocyte are the
Monocytes
Monocytes (5)
-large
-constitute around 5% of leukocytes
-large, eccentric nucleus that is relatively pale staining
-nuclear shape is variable
-may have 2+ nucleoli
Multinucleated giant cells are formed by
The fusion of macrophages
Function of monocytes (5)
-little function in circulating blood
-highly motile and phagocytes
-leave blood after 3 days and enter tissues
-respond to: necrotic tissue, microorganisms, and inflammation
-present with neutrophils in pus
Free roaming monocytes within tissue are
Macrophages
Fixed monocytes within the tissue are
Histiocytes
Thrombocytes (5)
-assist in the formation of blood clots (thrombi)
-cytoplasmic fragments of a large cell (megakaryocyte)
-very small
-appear in clumps
-contain granules that store factors associated with coagulation, inflammation, and immune function
True or False: Thrombocytes are not whole cells
True! Thrombocytes are cytoplasmic fragments of megakayocytes
2 stages of thrombocyte response to damaged endothelium:
- Aggregate to form an immediate plug to temporarily stop haemorrhage
- Catalyze the formation of fibrin clot to form a more permanent seal
Stem cells serve as the
Origin for each line of blood cells
Production of new blood cells is called
Haematopoiesis
Haematopoiesis occurs in (3)
-bone marrow
-lymphatic organs (ie. spleen)
-liver of fetus and young animals
The formation of red blood cells is called
Erythropoiesis
Erythropoiesis steps (3)
- Myeloid stem cells in bone marrow give rise to a L;argue nucleated cell (Proerythroblast)
- Nucleus undergoes chromatin condensation and is extruded as a Reticulocyte (immature RBC)
- Reticulocytes enter circulation and contain remnants of rRNA in cytoplasm
Severe haemorrhage/haemolysis will
Increase erythrocyte production
Reticulocytosis is when
Proportion of reticulocytes in circulation increases
Lymph consists of (6)
-excess interstitial fluid
-ions
-proteins
-cells (lymphocytes and macrophages)
-foreign matter (microbes and proteins)
-lipids from digestion
Lipid molecules that are too big to enter the circulatory system enter via ___ through ___
-lymphatic system
-lacteals in the intestinal villi
Two cell types found in lymph
-lymphocytes
-macrophages
Blood leaving the heart follows this pattern:
Elastic artiers (aorta) —> muscular arteries —> arterioles —> capillaries and sinusoids
Venules collect
The blood from capillaries
Blood returning to the heart follows this pattern:
Venules —> medium veins —> large veins (Vena Cava)
Valves (3)
-occur in many veins
-free edges flow in direction of blood
-prevent the back flow of blood
Elastic arteries (4)
-Aorta
-large vessels that transport blood from the heart
-walls contain large proportion of elastic fibres that stretch and recoil as blood is pumped
-limited amounts of smooth muscle
Muscular arteries (2)
-large amount of smooth muscle
-reduced elastic tissue
Arterioles (2)
-smaller than muscular arteries
-1-2 layers of smooth muscle only
Capillaries and sinusoids (2)
-thin walled: endothelium on a basement membrane
-sinusoids are wider (high exchange of solutes)
Venules (2)
-small Venules resemble capillaries but more expanded
-large Venules contain a layer of smooth muscle
Medium veins (2)
-similar in size to muscular arteries
-muscle layer is thinner
Large veins (3)
-ie. Vena Cava
-thick wall
-large lumen
Arteries vs Veins (3)
-artery walls are thicker with more smooth muscle and elastic fibres
-artery walls remain circular (ie. veins are able to collapse)
-arterial endothelium is folded (smooth in veins)
Smallest lymph vessels found in peripheral tissue are
Lymphatic Capillaries
Lymph vessel structure (4)
-similar to blood vessels
-single layer of endothelial cells
-collagen and elastin fibres in larger vessels
-smooth muscle present in larger vessels
Lymph vessels increase in size as
They approach the thorax
All lymph returns to
Venous circulation
The flow of lymph is
Unidirectional
Lymph flows in this pattern:
Blind-ending lymphatic capillaries —> afferent lymphatic vessels —> lymph node —> efferent lymphatic vessels —> major lymph trunk —> large vein in neck
Lymph vessels (4)
-permeable
-blind ending
-branch and anastomose to form a network within the connective tissue
-located close to capillaries and Venules
Four functions of blood
-transport of O2, CO2, nutrients, hormones, and waste
-homeostasis of body temperature, extracellular fluid, and pH buffering
-protection against infections
-blood clotting
Plasma without clotting factors is called
Serum
The Buffy coat consists of
WBCs and platelets
Gas (O2 and CO2) diffuses between
The terminal bronchioles and alveoli
CO2 in the body takes the form of
HCO3- (bicarbonate)
Haemoglobin molecules contains
4 subunits, each bound to a heme molecule
Each heme molecule binds to
An O2 molecule
Each haemoglobin molecule can carry up to
4 molecules of oxygen
More RBCs = more
Oxygen that can be transported
When oxygen binds to haemoglobin it is called
Oxyhaemoglobin (Hb-O2)
Oxygenated blood is
Bright red
The affinity of haemoglobin to O2
Increases as more O2 is bound
As more O2 binds to Hb,
More O2 can bind easier to Hb
P50 is the
PO2 at 50% Hb saturation
A right shift in the oxygen-Hb dissociation curve (2)
-P50 increases
-more O2 is off loaded in tissue
A left shift in the oxygen-Hb dissociation curve means (2)
-P50 decreases
-Hb holds onto O2
Alterations in the oxygen-Hb dissociation curve can occur by changes in (4)
-temperature
-PCO2
-H+ (Bohr effect)
-2,3 DPG (BPG) —> by product of glycolysis
Carbon monoxide has a
Greater affinity for the oxygen binding sites on haemoglobin than oxygen
CO poisoning is when
Haemoglobin concentration is normal but 50% is bound to CO rather than O2
Anaemia is when
Haemoglobin concentration is at 50%
Three purposes to CO2 transport
-convert CO2 to bicarbonate
-carry via haemoglobin
-dissolve in plasma
Carbaminohaemoglobin is formed when
Haemoglobin and CO2 bind
Bicarbonate is produced within
RBCs
A chloride shift is when
Bicarbonate goes into plasma and chloride comes out of cell
The CO2-Hb dissociation curve is ___ compared to O2-Hb dissociation curve
More linear
CO2 blood levels are maintained within very narrow parameters =
40-45 mmHg
Erythropoiesis is stimulated by
Erythropoietin (EPO) - a hormone produced by the kidney in response to hypoxia
Hypoxia (3)
-low O2 in tissue
-impairs normal metabolism
-can lead to cellular death
Hypoxaemia is when there is a
Low concentration of O2 in arterial blood
Tissue Hypoxia can occur in 4 ways
-Cytopathic (mitochondrial dysfunction, septic shock)
-Anaemic (blood does not have enough O2 carrying capacity)
-Stagnant (low cardiac output, low tissue perfusion)
-Hypoxemic (low O2 in arterial blood leading to low delivery of O2 to tissue)
Coagulation is a process by which
Blood turns from a liquid to a gel forming a blood clot
3 steps to Haemostasis
- Vascular Spasm
- Primary Haemostasis
- Secondary Haemostasis
What occurs during step 1 of Haemostasis
Vascular Spasm
-vasoconstriction helps reduce blood loss
-exposed collagen fibres bind with platelets
What occurs during step 2 of Haemostasis
Primary Haemostasis
-platelets immediately form a plug at site of injury
-degranulation occurs: Serotonin increases vasoconstriction (ie. decreases blood entering the area); ADP attracts more platelets to area; Thromboxane A2 aggregates and degranulates platelets
-positive feedback loop
What occurs during step 3 of Haemostasis
Secondary Haemostasis
-occurs simultaneously
-clotting factors (proteins in blood plasma) respond in a clotting cascade
-fibrin strands are formed via inactive fibrinogen to strengthen the platelet plug
Innate immune response (4)
-fast
-activate adaptive immune regions
-Neutrophils, Monocytes, Dendritic Cells, Granulocytes, and Natural Killer Cells
-phagocytosis
Adaptive Immune Reposne (4)
-ie. acquired immune response
-specific
-slower
-leads to enhanced response to future exposure of pathogens (ie. antibodies)
Cells of the adaptive immune response include (3)
-B cells
-T Cells (CD4+ and CD8+)
-Natural Killer Cells
First cells to arrive during immune response are the
Neutrophils
7 cells of the innate immune response
-neutrophils
-monocytes (differentiate into macrophages)
-dendritic cells
-eosinophils
-basophils
-mast cells
-Natural killer cells
Dendritic cells activate
T Cells of the adaptive immune system
CD4+ (3)
-helper T cells
-coordinate immune response
-differentiate into inflammatory mediators
B cells make
Antibodies that bind to pathogens
CD8+ (2)
-cytotoxic T cells
-kill infected/tumour cells without damaging surrounding tissue
How many oxygen molecules can bind to one haemoglobin protein
4
A decrease in pH will
Increase acid and increase O2 offloading
What is the first thing that occurs when a blood vessel is injured
Vascular smooth muscle cells of the damaged vessel constrict, reducing the amount of blood flow to the area
