What percentage of leukocytes do monocytes constitute?
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Around 5%.
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What percentage of leukocytes do monocytes constitute?
Around 5%.
What is the size range of neutrophils?
10 - 12 μm.
How long do neutrophils typically remain in circulation?
5 days.
What was the understanding of basophils' functions until recently?
Poorly understood until around 2009.
What are basophils precursors to?
Tissue mast cells.
What is the function of the free edges of valves in veins?
They allow blood to flow in the direction of the blood.
How do medium veins compare in size to muscular arteries?
They are comparable in size, but the muscle layer is much thinner.
What is a characteristic of lymph vessels?
They are permeable and blind-ending.
What is the process of producing new blood cells called?
Haematopoiesis.
What is the structure of capillaries?
Thin-walled with endothelium on a basement membrane.
Where do lymph vessels form a network?
Within connective tissue.
How many layers of smooth muscle do arterioles have?
1 to 2 layers of smooth muscle only.
What is a key characteristic of the walls of elastic arteries?
They contain a large proportion of elastic fibers.
Where does haematopoiesis primarily occur?
In bone marrow and lymphatic organs (e.g., spleen).
What is the structure of lymph vessels?
They have a single layer of endothelial cells.
What are the smallest vessels in peripheral tissues?
Lymphatic capillaries.
What characterizes muscular arteries?
They have large amounts of smooth muscle and reduced elastic tissue.
Where do valves occur in blood vessels?
In many veins where the diameter is greater than 2 mm.
What is a key characteristic of erythrocytes regarding their shape?
They are very plastic and can conform to narrow vessels.
What happens to lymphatic vessels as they approach the thorax?
They increase in size.
What is the composition of erythrocytes' cytoplasm?
60% water and 40% solid (hemoglobin).
What is the flow direction of lymph?
Unidirectional.
What type of stem cell is responsible for producing lymphocytes?
Lymphoid stem cell.
What is the primary function of NKC?
To identify and destroy infected or cancerous cells.
How do lymph vessels connect with each other?
They branch and anastomose.
How do sinusoids differ from capillaries?
Sinusoids are wider in diameter than capillaries.
What is the amount of smooth muscle in elastic arteries?
Limited amounts.
What percentage of leukocytes do basophils represent?
Up to 1.5%.
What type of granules do eosinophils have?
Large, acidophilic granules that are red.
How long do monocytes circulate in the blood before entering tissues?
About 3 days.
What is the primary function of lymphocytes?
To serve as the body's immunological defense system.
What is the primary function of leukocytes?
Responsible for the body's immune response.
What do lymphatic vessels eventually form?
Major lymph trunks.
Which type of blood cell is the most numerous?
Erythrocytes.
How do the size of eosinophils compare to neutrophils?
Eosinophils are slightly larger, measuring 10 - 15μm.
What is the main focus of Episode 3 of 'Cells at Work'?
The episode focuses on the influenza virus and the body's immune response.
What are the two types of cells monocytes can differentiate into after leaving the blood?
Macrophages (free roaming) and histiocytes (fixed within tissue).
In which year was the Atlas of Microscopic Anatomy published?
What is the size range of basophils?
10 - 15 μm.
What is the lifespan of thrombocytes in the bloodstream?
Approximately 7 to 10 days.
What is the size range of erythrocytes?
4 - 8 μm.
What are the larger vessels that lymphatic capillaries lead to?
Lymphatic vessels.
What do valves in veins prevent?
Back-flow of blood.
What is a haemocytoblast?
A type of stem cell that gives rise to blood cells.
What is the lifespan of erythrocytes?
120 days.
What factors can affect the number of leukocytes in the blood?
Infection and inflammation.
Name the types of granular leukocytes.
Basophils, neutrophils, and eosinophils.
What is a unique characteristic of monocytes regarding nucleoli?
They may have 2 or more nucleoli.
What is the shape of erythrocytes?
Round and biconcave.
What is the process of erythrocyte formation called?
Erythropoiesis.
What do monocytes present with in pus?
Neutrophils.
What are the characteristics of large veins?
They have a thicker wall and larger lumen, but a similar structure to medium veins.
How do arterioles compare in size to muscular arteries?
Arterioles are much smaller than muscular arteries.
How do neutrophils degrade the material they phagocytose?
Using enzymes contained within their granules.
What is a distinguishing feature of monocytes' nuclei?
They have a large, eccentric nucleus that is relatively pale-staining.
Where are lymph vessels located in relation to capillaries and venules?
They are close to capillaries and venules.
What serves as the origin for each line of blood cells?
Stem cells.
What is a progenitor cell?
A cell that is derived from a stem cell and can differentiate into a specific type of cell.
What do efferent lymphatic vessels lead to?
Major lymph trunk.
What colors are associated with the different granular leukocytes?
Basophils (blue), neutrophils (white), eosinophils (red).
What is a key structural difference between artery walls and vein walls?
Artery walls are thicker.
What are the three classes of lymphocytes based on functional grounds?
T cells, B cells, and Natural killer cells.
What type of parasites are basophils involved in responding to?
Helminth parasites.
What are elastic arteries?
Large vessels that transport blood from the heart.
What are the two types of cells activated by NKC?
B Cells and T Cells.
How do elastic arteries respond as blood is pumped?
They stretch and recoil.
In what areas are capillaries and sinusoids typically found?
In areas where there is a high exchange of solutes.
What do larger venules contain?
A layer of smooth muscle.
What role do macrophages play in the immune response to influenza?
They engulf and digest pathogens, including the influenza virus.
Where does the lymph ultimately drain into?
Large vein in the neck.
Where are thrombocytes produced?
In the bone marrow from megakaryocytes.
What is the first type of blood vessel that blood encounters after leaving the heart?
Elastic arteries (e.g. aorta).
What does NKC stand for?
Natural Killer Cells.
How do leukocytes interact with other tissues?
They migrate to other tissues.
What percentage of leukocytes do eosinophils represent?
2 - 8%.
What happens to neutrophils during an infection?
They are mobilized in large numbers to the focus of infection.
What follows the afferent lymphatic vessels in the lymphatic flow?
Lymph node.
What is the main constituent of pus?
Neutrophils.
What specialized protein do erythrocytes contain?
Haemoglobin.
Do blood cells have a limited life span?
Yes, blood cells have a limited life span.
What percentage of body weight does blood constitute in mammals?
7 - 8%.
What percentage of blood volume is plasma?
45 - 65%.
What components are dissolved in plasma?
Gases, electrolytes, proteins, carbohydrates, lipids, hormones.
How do eosinophils respond to helminth parasites?
They kill helminth parasites and release granule contents onto them.
What do proerythroblasts enter circulation as?
Reticulocytes.
What will a blood smear from an animal with flea allergy dermatitis show?
Eosinophilia.
What are thrombocytes commonly known as?
Platelets.
What does the fibrin clot formed by thrombocytes provide?
A more permanent seal.
What is the primary function of neutrophils?
To phagocytose bacteria and other particulate material.
What is the primary function of monocytes in circulating blood?
They have little function in circulating blood.
What are the two main groups of leukocytes?
Granular and Non-granular leukocytes.
What is the primary function of thrombocytes?
To aid in blood clotting.
What do small venules resemble?
Capillaries, but are more expanded.
How does the nuclear shape of monocytes change as they mature?
It often becomes more horseshoe-shaped.
What is a blast cell?
An immature precursor cell that is in the process of developing into a specific type of blood cell.
What triggers monocytes to respond?
Necrotic tissue, microorganisms, and inflammation.
What are the types of non-granular leukocytes?
Lymphocytes and monocytes.
What shape do immature neutrophils (band neutrophils) have?
'U' or 'S' shaped.
From which type of stem cells are erythrocytes derived?
Myeloid stem cells in the bone marrow.
What is the primary function of thrombocytes?
Assist in the formation of blood clots (thrombi).
How commonly are basophils encountered?
They are rarely encountered.
In what type of reactions are eosinophils implicated?
Hypersensitivity reactions.
What are leukocytes commonly known as?
White blood cells.
What is the largest type of vein that returns blood to the heart?
Large veins (e.g. vena cava).
How do lipids from digestion enter the lymphatic system?
Through lacteals in the intestinal villi.
What is the size range of monocytes?
15 - 20μm.
What are thrombocytes commonly known as?
Platelets.
What are neutrophils?
The most numerous type of granulocytes and leukocytes in carnivores.
Which organ is involved in haematopoiesis in fetuses and young animals?
The liver.
How do thrombocytes contribute to hemostasis?
By aggregating at the site of a blood vessel injury.
What is the shape of the nucleus in eosinophils?
Bilobed nucleus.
How does the body recognize the influenza virus?
Through specific receptors on immune cells that detect viral particles.
What are some locations where lymphocytes are concentrated?
Lymph nodes, nodules, spleen, and Peyer’s patches in the intestine.
What is a distinctive feature of basophils' nucleus?
It is bilobed and often obscured by granules.
What do B cells produce?
Antibodies, contributing to the humoral immune response.
What role does haemoglobin play in erythrocytes?
It carries oxygen and carbon dioxide.
What is the size range of thrombocytes?
2 - 4 μm (very small).
What collects blood from capillaries?
Venules.
What do the granules in thrombocytes store?
Factors associated with coagulation, inflammation, and immune function.
What are the two stages of thrombocyte response to damaged endothelium?
What happens to large lipid molecules that cannot enter the circulatory system?
They enter via the lymphatic system.
What type of capillaries are involved in the lymphatic system?
Blind-ending lymphatic capillaries.
What additional components are found in larger lymph vessels?
Collagen and elastin fibers, as well as smooth muscle.
How do neutrophils' granules appear?
Lightly staining and usually not visible ('white').
What is a characteristic feature of mature neutrophils?
They have a multilobed nucleus.
What do the granules in basophils contain?
Histamine, heparin, and serotonin.
What role do basophils play in relation to T lymphocytes?
They are involved in the activation of a subset of T lymphocytes.
How are basophils visually characterized?
By many large, darkly basophilic granules.
What are the main components of lymph?
Excess interstitial fluid, ions, proteins, cells, foreign matter, and lipids.
How do T cells and Natural killer cells kill infected cells?
By releasing granules that target and destroy virus-infected & tumor cells.
Why is the proportion of reticulocytes clinically significant?
It indicates reticulocytosis, which can reflect the body's response to anemia or other conditions.
What is the function of a myeloid stem cell?
To give rise to various types of blood cells, excluding lymphocytes.
What is the primary function of erythrocytes?
To carry O2 and CO2.
How are arteries and veins positioned in relation to the same tissue?
They are usually side by side.
What type of muscle is present in larger lymph vessels?
Smooth muscle.
Are eosinophils frequent or infrequent in the blood?
Relatively infrequent.
What are thrombocytes also known as?
Platelets.
What forms multinucleate giant cells?
Fusion of macrophages.
What is the large nucleated cell that gives rise to erythrocytes?
Proerythroblast.
What is the function of elastic fibers in arteries?
They recoil and constrict the lumen of arteries.
What percentage of blood lymphocytes are small lymphocytes?
97%.
Which type of cell is primarily involved in fighting the influenza virus?
White blood cells (leukocytes).
Where are lymphocytes primarily found?
In circulation in blood and lymph, and concentrated in lymphoid tissue.
What is the role of T cells in the immune response?
Responsible for cell-mediated immune response and killing virus-infected & tumor cells.
What is the abundance rank of lymphocytes among leukocytes in blood?
They are the second most abundant leukocyte after neutrophils.
In what type of reactions are basophils implicated?
Hypersensitivity reactions such as asthma, hayfever, and anaphylactic shock.
What happens to the nucleus of a proerythroblast during erythropoiesis?
It undergoes chromatin condensation and is extruded.
What is the function of Natural killer cells?
They are involved in cell-mediated immune response and kill virus-infected & tumor cells.
What is the term for the increase in the proportion of reticulocytes in circulation?
Reticulocytosis.
What type of muscle and fibers are more abundant in arteries?
More smooth muscle and elastic fibers.
What type of blood vessel follows elastic arteries?
Muscular arteries.
What is one of the primary functions of eosinophils?
Phagocytose antigen/antibody complexes.
What is the shape of a lymphocyte's nucleus?
Ovoid to kidney-shaped.
What is the size range of small lymphocytes?
6 - 9 μm.
How do the ion concentrations in lymph compare to plasma?
They are similar.
What is the pH nature of plasma?
Alkaline.
Are thrombocytes whole cells?
No, they are cytoplasmic fragments of a large cell called megakaryocyte.
What are plasma cells?
A subset of B cells that produce antibodies.
How do reticulocytes differ from mature erythrocytes?
Reticulocytes are slightly larger and contain remnants of rRNA, which can be seen as stippling when stained with methylene blue.
What staining method is used to identify reticulocytes?
Methylene blue staining.
What foreign matter can be found in lymph?
Microbes and proteins.
What is the significance of the immune response depicted in the episode?
It illustrates how the body defends itself against viral infections.
Do erythrocytes have a nucleus in mammals?
No, they are anucleate.
What are the smallest blood vessels that blood travels through before reaching capillaries?
Arterioles.
What is the main difference between mammalian and avian/reptilian erythrocytes?
Mammalian erythrocytes have no nucleus or organelles when mature, while those in birds and reptiles are nucleated.
What is the immature form of erythrocytes released into circulation called?
Reticulocyte.
What remains in the cytoplasm of reticulocytes?
Remnants of rRNA.
What triggers an increase in erythrocyte production?
Severe haemorrhage or haemolysis.
What is the purpose of the immediate plug formed by thrombocytes?
Temporarily stops hemorrhage.
What do the granules of eosinophils contain?
Hydrolytic enzymes and peroxidases.
What happens to veins when they are not filled with blood?
Veins collapse.
What are erythrocytes commonly known as?
Red blood cells.
What type of blood vessel is larger than venules and returns blood to the heart?
Medium veins.
What shape do artery walls maintain?
They remain circular.
What is a Barr body?
An inactive X chromosome found in females.
What are the formed elements of blood?
Erythrocytes, leukocytes, and thrombocytes.
How does the endothelium of arteries differ from that of veins?
Arterial endothelium is folded, while veins are smooth.
What is the concentration of proteins in lymph compared to plasma?
Lower concentrations than plasma.
What types of cells are found in lymph?
Lymphocytes and macrophages.
Why is the proportion of mature to immature neutrophils clinically important?
It can indicate health status or response to infection.
What are multinucleate giant cells reminiscent of?
Osteoclasts.
What are the sites of exchange between blood and tissues?
Capillaries and sinusoids.
How do thrombocytes appear on blood smears?
Often in clumps.
What is the size range of large lymphocytes?
12 - 15 μm.
