Chapter 12 - Blood Flashcards
Describe the composition of blood
Approximately 7% of body weight
55% plasma
45% formed elements
Describe the funcitons of blood
Transportation
* Oxygen, nutrients, waste products, hormones,
platelets
Regulation
*Body temperature, tissue fluid content, blood pH
Defense system
* White cell phagocytosis, platelets
Describe the functions of blood
- Transport oxygen to tissues (hemoglobin)
–Oxygen, nutrients, waste products, hormones,
platelets
–Transport carbon dioxide to lungs - Regulation
–Body temperature, tissue fluid content, blood pH - Defense system
–White cell phagocytosis, platelets
Describe the difference between plasma and serum
Plasma is the liquid portion of the blood after all the blood cells have been removed. Water is the main ingredient in plasma.
Serum contains all the other proteins found in plasma’s water but the clotting factors are removed.
If a blood sample from an animal sits in a tube for several minutes, you’ll notice a layer of colorless or straw-colored fluid at the top of the sample, a small thin white layer, and then a clot of gel-like red material at the bottom.
- Top: Serum
- Middle: white blood cells (not always visible to the naked eye)
-Bottom: blood clot
Fibrinogen is not found in serum
*Plasma protein
*Assists in the blood clotting process
* Leaves plasma to help clot blood
Not as important- To use plasma for testing, you must add an anticoagulant to the blood sample to block the clotting process. Anticoagulants used include heparin or sodium citrate.
Describe the structure of Erythrocytes
Erythrocytes = Red blood cells
–biconcave disks—cells with deep depressions in the center of each side. -(Dogs/humans -Other species have round cells without the central depressions)
Cell membrane is quite flexible,
–allows the red blood cell to squeeze through even the narrowest capillary.
-Erythrocyte cell membrane is close the capillary endothelium
–improves the efficiency of gas exchange by decreasing the distance across which the gases must travel.
–Appearance
* Non-nucleated
*Stain red
Mature erythrocytes of most mammals don’t possess a nucleus, while immature erythrocytes in the bone marrow have a nucleus.
–As it grows, it loses this nucleus and starts producing hemoglobin.
——Can’t manufacture new proteins or divide to produce more cell
Describe the function of Erythrocytes
The primary responsibility of the erythrocyte is the transport of gases throughout the body. Oxygen is carried from the lungs to the cells, and carbon dioxide is carried from the cells to the lungs.
Describe the structure of Leukocytes
White blood cells
Leukocytes are generally slightly larger than erythrocytes, and all possess a nucleus; thus, unlike erythrocytes, they’re capable of normal protein synthesis.
Formed in bone marrow by stem cells
Two categories of leukocytes are granulocytes and agranulocytes- color and granules depend on specific type.
*Neutrophils
*Eosinophils
*Basophils
* Lymphocytes
* Monocytes
Describe the function of Leukocytes
Provide defense for the body against foreign invaders
*Phagocytosis
*Immunity
Each type has its own role
** not function but something to remember
Produced in bone marrow
* Use peripheral blood to travel to site of activity
Describe the structure of Thrombocytes
Platelets
Not complete cells
* Pieces of cytoplasm from giant multinucleated bone marrow cells
Appearance on blood smear:
* Non-nucleated
* Round to oval in shape
* Clear cytoplasm
* Small blue to purple granules in cytoplasm
* Size varies by species
* Generally smaller than RBCs
* Macroplatelets are occasionally seen
Describe the function of Thrombocytes
Most important for normal hemostasis
* Formation of platelet plug
*Stabilization of the plug
Clotting process: complex!
Absence of platelets can result in bleeding disorders
Describe the structure of the hemoglobin molecule
It is a protein
Made of four heme units associated with on globin chain
–each heme unit contains an iron molecule to which a O2 molecule attaches
List and describe the blood cell parameters of the CBC
One of the most useful clinical evaluations
*Plasma proteins
* Red blood cells
* White blood cells
*Platelets
Health status of animal is reflected in results
Describe the indications and goals of transfusion
Used to replace fluid or blood that has been lost or destroyed
*Involves taking blood or blood component from donor animal and injecting it into recipient animal
Indications for a transfusion
* Rapid blood loss
*Severe anemia
* Coagulation factor deficiency
* Lower than normal plasma protein
* Thrombocytopenia
Describe the two parts of the lymphatic system
Primary (lymphocytes)
* Thymus
*Bursa of Fabricius (Avian)
*Peyer’s patches - Intestinal tract
Secondary - where invaders are fought
*Spleen
* Lymph nodes
* Tonsils
Thymus
Located in cranial thoracic region (mediastinum)
Most prominent in young animals
*Atrophies with age
Produces mature T-cells from precursors sent from the bone marrow
Cells leave thymus and travel to secondary lymphoid tissue
*Important in stimulating cell-mediated immune response
Animal Lymphoid Organs
Bursa of Fabricius
* Found only in birds
* Round sac located above the cloaca
*Similar in structure and function to the thymus Lymphoid Organs
Peyer’s patches
* Located in wall of small intestine (GALT)
*Structure and functions vary among species
*Activate B cells to produce antibodies
Describe the formation of lymph fluid
Lymph starts outas excessive tissue fluid
Capillaries in tissue join to form larger vessels to propel lymph toward the heart
Lymph eventually joins bloodstream
Describe the circulation of the lymphatic system
Excessive interstitial fluid picked up by small lymph capillaries
— Fluid enters/leaves tissue spaces due to blood pressure and osmotic pressure
Lymph capillaries join together to form larger and larger lymph vessels
Utilization of one-way valves and body movements to propel lymph toward the heart
Lymph passes through at least one lymph node and picks up lymphocytes
Macrophages in lymph node remove microorganisms
Lymph is emptied into vena cava just before large vein enters the heart
Lymph has come full circle (Secret of Life!)
* Originated in plasma
* Has returned to plasma
Blood
A fluid connective tissue
A living tissue even after it is taken from an animal
* RBCs utilize plasma glucose for energy
* Glucose cannot be replenished in a tube after RBCs use it
Functions
* Transport oxygen to tissues (hemoglobin)
* Transport carbon dioxide to lungs
* Maintain cell shape and deformability
Can be categorized as
*Whole Blood contained in cardiovascular system (unclotted)
*Peripheral Blood
hemoglobin
Found in erythrocytes-
a protein molecule with an iron molecule in the center. Hemoglobin binds both oxygen and carbon dioxide for transport.
Hemoglobin is manufactured in the immature erythrocyte (which still possesses a nucleus) in the bone marrow. However, once the erythrocyte matures, no nucleus and no endoplasmic reticulum are present to manufacture more hemoglobin. This fact is crucial, because under certain conditions, the hemoglobin molecule is irreversibly damaged and becomes of no use for gas transport.
Hematopoiesis
Production of all blood cells
Continuous process throughout animal’s life
Occurs primarily in red bone marrow
*Adult sites: skull, ribs, sternum, vertebral column, pelvis, proximal ends of the femurs
* Less-active bone marrow = yellow bone marrow
Occurs in liver and spleen in times of great need
What is found in Plasma
Water containing
Dissolved electrolytes
pH buffers
Proteins of many types and functions
Fats
Sugars
Vitamins
Minerals
nucleated red blood cells (NRBCs)
Immature erythrocytes in the bone marrow have a nucleus
Life span of red blood cells
Normal life span varies with species
* From mice (20-30 days) to cats (68 days) to dogs (120 days) to horses and sheep (150 days) to cows (160 days). (Important one to remember is dogs and cats - )
Process of aging = senescence
*Enzyme activity decreases
* Cell membrane loses deformability
*About 1% of cells removed from circulation daily
* Destruction: extravascular or intravascular
Inflammation
Inflammation in tissue is clinically defined by four classic hallmarks: redness, heat, swelling, and pain. Inflammation is a consequence of the body’s attempt to fight infection or repair damaged tissue.
Granulocytes
A type of leukocytes
Prominent granules appear in their cytoplasm when viewed on a stained blood smear
Eosinophils
* Granules pick up acidic stain and appear red
Basophils
* Granules pick up basic stain and appear blue
Neutrophils
* Don’t pick up either stain well
* Appear colorless or faintly violet
Agranulocytes
A type of leukocyte
* Lymphocytes and monocytes
WBCs that don’t contain specific staining granules in their cytoplasm
Include lymphocytes and monocytes
Lymphocyte Characteristics
Easily recognized by round or oval nucleus
Minimal, clear, almost colorless cytoplasm
Most live in lymphoid tissue and circulate between these tissues and blood
Lymphocyte Functions
3 different types of lymphocytes and plasma cells with individual functions that regulate the immune system
T lymphocytes (T cells) - Responsible for cell-mediated immunity and active B cells
B lymphocytes (B cells) - humoral immunity
Natural killer (NK) cells -Kill virus infected cells, stressed cells and tumor cells
Plasma Cells - Release antibodies
T lymphocytes (T cells)
–Most lymphocytes in peripheral blood are T cells
— Start in bone marrow and then processed/Mature in thymus before going to peripheral lymphoid tissue
— Then migrate to other lymphoid tissues and the blood
—Single nucleus
Function
—-Responsible for cell-mediated immunity
—- Responsible for activating B cell
They are like marines- do hand to hand combat
B lymphocytes (B cells)
Inactive B cells travel through lymph nodes, spleen, and other lymphoid tissue
* Rarely in peripheral blood
Responsible for antibody production
* Each B cell produces only one antibody type against one specific antigen
* Surface receptors are shaped to fit only one antigen shape (epitope)
Extracellular
Differentiate into plasma cells (plasma cells make antibodies)
Single nucleus
Artillery- shoot antibodies
Natural Killer (NK) Cells
Surveillance and Destruction
Granular lymphocytes found in blood and lymph
Have ability to identify and kill virus-infected cells
Bind to cell and induce cellular changes that lead to cellular death = apoptosis
* Do not ingest the target cell
2 types of receptors
*Killer-activating receptor (KAR)
*Killer-inhibitory receptor (KIR)
Part of both innate and adaptive immune systems
Memory Cells
Both T cells and B cells can become memory cells
Clones of an original lymphocyte (B and T cells)
Stay in lymph nodes or circulate in blood
* Look for antigen that originally triggered their
activation
* When find antigen, immune response is activated
* Response stronger and quicker than initial
response
Clotting Process
Also called coagulation cascade
mediated by about 30 proteins known as clotting factors
*Platelet adhesion
*Platelet aggregation
* Thrombin is formed
* Converts fibrinogen to strands of fibrin
* Fibrin attaches to platelet surface cementing platelets in place (clot)
hemolysis
Old red blood cells are destroyed. Allows for the components of the red blood cell to be put back into circulation to help build new red blood cells.
extravascular hemolysis,
the old erythrocyte is removed from circulation via macrophages. (90%)
-Macrophages destroy the cell, leaving amino acids, iron, and heme.
-heme is then further broken down into bilirubin.
–Iron is transported to the bone marrow where it will make new red blood cells
–The amino acids and the bilirubin are then taken to the liver for recycling.
—The amino acids are used to make more proteins.
–bilirubin becomes conjugated (bound to glucuronic acid)
– extracted from intestines as bile pigment
– converted to urobilinogen by intestinal bacteria
—- eliminated as feces and urine
If the liver is overwhelmed with the bilirubin, it can be deposited in the tissues, causing them to take on a yellowish-hue called jaundice or icterus.
Intravascular hemolysis
- old red blood cell is destroyed while still in the blood vessel.
- 10% of hemolysis (most is extravascular)
- Many stresses can cause rupture of blood cell in blood vessel
- the red blood cell releases hemoglobin into circulation.
—It’s then taken to the liver by haptoglobin
— if there is an excess it’s taken up by the kidneys and released in urine, called hemoglobinuria, causing the urine to take on a red color.
Less important: Sometimes, the hemoglobin is in such supply that it changes the color of the plasma to pink, red, or brown—a condition known as hemoglobinemia.
heme
The part of certain molecules that contains iron
Packed Cell Volume
= Hematocrit (Hct)
Volume of packed RBCs measured and expressed as a percent of total volume of blood
Lymphatic system
2 separate parts of animal’s immune system
System of ducts and fluid lymph
*System picks up fluid leaked from capillaries
* Lymph ducts carry lymph to blood vessels near heart
* Lymph is put back into bloodstream
System of lymphoid organs and tissues
* Lymph nodes, spleen, thymus, tonsils, and gut associated lymph tissue (GALT)
Lymphatic System Functions
Removal of excess tissue fluid
*Inadequate lymph drainage can result in edema
Waste material transport
Filtration of lymph
* Lymph passes through lymph nodes
Protein transport
think sewage system
Lymph Characteristics
Transparent or translucent liquid
Contains varying numbers of cells
*Primarily lymphocytes
Different from plasma
* More water, sugar, and electrolytes
* Fewer of the larger proteins found in plasma
Lymph from digestive system = chyle
*Postprandial (after dinner or lunch) lipemia
(lymph system similar to airplane security line)
Secondary Lymphoid Organs
Include spleen, lymph nodes, and tonsils
Enlarge in response to antigenic stimulation
Main function
* Trap and process antigens and mature lymphocytes that mediate immune responses
Spleen General facts
Largest lymphoid organ
Storage of blood
Lymphocyte cloning
Removal of old RBC’s
(Secret of Life!)
Spleen Physiology
Acts as a reservoir for blood when animal is at rest
*Spleen gets larger when storage spaces are filled with blood
When body needs excess blood cells:
* Trabeculae contract
*Blood is squeezed back into circulation
*Spleen gets smaller
Not essential for life (splenectomy)
White pulp has immunological functions
*Phagocytic cells react to antigens in bloodstream
Macrophages in red pulp remove worn, damaged
blood cells
Lymph nodes
Small, kidney bean-shaped filters located along lymphatic vessels throughout the body
Trap antigens and other foreign materials in lymph
2 sections
* Cortex
— Lymph nodules
* Medulla
—Tissue macrophages, B cells and T cells
Drain to organs in their associated locations
Can give clue to health of an animal
* Nodes more easily palpated when enlarged in response to antigenic stimulation
* Fine Needle Aspirate (FNA) and cytology for evaluation for abnormalities
Tonsils
Nodules of lymphoid tissue that are not covered with a capsule
Found in epithelial surfaces all over the body
* Most familiar in pharyngeal region
* *Pharynx, larynx, urinary, & reproductive tracts
Present at beginning of lymph draining system
Function to prevent spread of infection into respiratory and digestive systems before it can cause disease
Part of the MALT system
Tonsils vs. Lymph Nodes
Tonsils
* Found close to moist epithelial surfaces
* Found at beginning of lymph drainage system
* No capsule
Lymph nodes
* Found along lymph vessels
* Have a capsule
Erythropoiesis
The process by which red blood cells are created.
Fibrinogen
Clotting agent
pluripotential
A type of stem cell from which all cells have evolved
Hypoxia
Oxygen deficiency. Leads to the production of blood. Many causes. Bluish tinge of mucus membranes
How does red blood cell carry oxygen to tissues
Erythrocytes carry oxygen to tissues through the production of the protein hemoglobin that binds with the oxygen. Hemoglobin is a protein composed of two components—heme and globin. Every heme group can carry a molecule of oxygen. Four heme groups attach to each globin molecule, so each hemoglobin molecule can carry four molecules of oxygen. The oxygen attaches to iron atoms (Fe++) that are part of each heme group.
Neutrophils
40 - 75% of circulating leukocytes
polymorphonuclear (many lobed nucleus - PMN)
Larger than RBC
Smaller than monocytes
Doesn’t stain well
Involved in early stage of inflammation- think of them as traffic cops
Phagocytosis in tissues
Diapedesis
The process in which the white blood cells squeeze through the endothelium
Chemotaxis
– process that attracts neutrophils to inflammatory chemicals at site of infection
Opsonization
- Coating process that makes microorganism more recognizable
*Allows neutrophil to begin phagocytosis
Encapsulated microorganism is coated with a plasma protein
*A specific antibody = opsonin
Neutrophil Phagocytosis
Microorganisms are engulfed and enclosed in phagosome
Cytoplasmic granules move close to edge of phagosome
Granules release lysosomal enzymes which help kill the microorganisms
Eosinophil Characteristics
Named for red granules of mature cells when viewed on a stained blood smear
Segmented nucleus – usually 2 lobes
Slightly larger than neutrophils
Produced in bone marrow
Stay in blood circulation for 3-8 hours before migrating to tissue, where they remain
Eosinophil Functions
Inflammatory response
– allergic reactions (anaphylaxis)
Immunity
Phagocytosis
in body tissue
Basophil Characteristics
Named for the blue granules of mature cells when viewed on a stained blood smear
Multi-lobed nuclei
Similar in size to neutrophils
Basophil Functions
Least phagocytic of the granulocytes - initiates immune response
Contents of granules
* Histamine
* Heparin
Share some characteristics with tissue mast cells
*Both contain Immunoglobulin E
in body tissue
Monocyte characteristics
Largest WBC in circulation
Nuclei can be of many different shapes
* Round to pseudo-lobed
Abundant cytoplasm
*Stains gray
* May contain vacuoles
Super PacMan Phagocytosis in blood or tissues
Monocyte Functions
Participates in inflammatory response
Known as macrophage when it enters tissues
* Lives in tissues for 100+ days
Tissue macrophages and monocytes
* Constitute mononuclear phagocyte system (MPS)
* Clean up cellular debris after an infection/inflammation clears up
* Can also ingest antigens
Antigen
a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies.
vena cava
The superior vena cava and inferior vena cava are very large veins that bring deoxygenated blood to your heart to get oxygen.
GALT
All the lymphoid tissue in the gut is collectively called GALT (gut-associated lymphoid tissue).
The Spleen anatomy
Tongue-shaped organ located on the left side of the abdomen
* Near stomach in simple-stomached animals
* Near the rumen in ruminants
Covered with capsule of fibrous connective tissue and smooth muscle
* Trabeculae from capsule go into soft tissue of spleen
*Smooth muscle cells contract and squeeze blood out of spleen and back into circulation
Whole Blood
Contained in the cardiovascular system
Peripheral Blood
Circulating in blood vessels carrying oxygen, nutrients and waste products
Composition of Plasma
– 7% proteins
—- Albumins
——Globulins
— Fibrinogen
–91% water
–2% Other solutes
—ions
— nutrients
– waste products
—gases
—-regulatory substances
Composition of formed elements of blood
-Erythrocytes (5.5 - 8.5 mill)
-Platelets ( 200-500 thous, number per cubic mm)
-Leukocytes (6 - 17 thous)
– 60 - 77% neutrophils
– 12 - 30% Lymphocytes
– 3 - 10% monocytes
– 2 - 10% Eosinophils
– (rare) Basophils
-
Kidneys blood cells
*releases erythropoietin to stimulate erythrocyte production by the bone marrow
*Can take up hemoglobin and release in urine, called hemoglobinuria, causing the urine to take on a red color.
– hemoglobin mainly taken by the liver
biconcave shape of erythrocytes
provides more membrane surface area for diffusion of oxygen and carbon dioxide.
renders the cell deformable and thus can take in water.
provides a central pallor to the cell
Haptoglobin
the transport plasma protein that picks up hemoglobin in the blood and takes it to the liver
-intravascular hemolysis
Band Cells
Immature form of neutrophils, which are the most commonly produced white blood cell.
multipotent
cells that can renew for extended periods of time and differentiate into specific cell types with specific functions
Penia
deficiency
