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Blood Considered A Tissue

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Last Updated: 02 July 2021

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General | Latest Info

Your blood is made up of liquid and solids. The liquid part, called plasma, is made of water, salts, and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells deliver oxygen from your lungs to your tissues and organs. White blood cells fight infection and are part of your immune system. Platelets help blood to clot when you have cut or wind. Bone marrow, spongy material inside your bones, makes new blood cells. Blood cells constantly die and your body makes new ones. Red blood cells live about 120 days, and platelets live about 6 days. Some white blood cells live less than a day, but others live much longer. There are four blood types:, B, AB, or O. Also, blood is either Rh - positive or Rh - negative. So if you have type blood, it's either positive or negative. Which type you are is important if you need a blood transfusion. And your Rh factor could be important if you become pregnant - incompatibility between your type and baby's could create problems. Blood tests such as blood count tests help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working. Problems with your blood may include bleeding disorders, excessive clotting and platelet disorders. If you lose too much blood, you may need a transfusion.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Bone

Bone, or osseous tissue, is connective tissue that has large amounts of two different types of matrix material. The Organic matrix is materially similar to other connective tissues, including some amount of collagen and elastic fibers. This gives strength and flexibility to tissue. Inorganic matrix consists of mineral salts, mostly calcium, that give tissue hardness. Without adequate organic material in the matrix, tissue breaks; without adequate inorganic material in the matrix, tissue bends. There are three types of cells in the bone: osteoblasts, osteocytes, and osteoclasts. Osteoblasts are active in making bone for growth and remodeling. They deposit bone material into matrix and, after the matrix surrounds them, they continue to live, but in a reduced metabolic state as osteocytes. Osteocytes are found in the lacunae of bone and assist in maintenance of bone. Osteoclasts are active in breaking down bone for bone remodeling, providing access to calcium stored in tissues in order to release it into blood. Osteoclasts are usually found on the surface of tissue. Bones can be divided into two types: compact and spongy. Compact bone is found in shaft of long bone and surface of flat bones, while spongy bone is found at the end of long bone. Compact bone is organized into subunits called osteons. Blood vessels and nerves are found in the center of osteon within a long opening called Haversian canal, with radiating circles of compact bone around it, known as lamellae. Small spaces between these circles are called lacunae. Between lacunae are microchannels called canaliculi; they connect lacunae to aid diffusion between cells. Spongy bone is made of tiny plates called trabeculae, which serve as struts, giving spongy bone strength.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Adipose (Fat) Tissue

Key facts about adipose tissue

DefinitionA type of specialized connective tissue whose main functions are to store the energy, protect the organs and contribute to the endocrine profile of the body
TypesDepending on location; parietal fat and visceral fat Depending on structure; white adipose tissue and brown adipose tissue
StructureAdipocytes (white, brown and beige) Thin extracellular matrix consisting of reticular fibers
FunctionEnergy storing, hormone production, thermal isolation (white adipose tissue); thermogenesis (brown adipose tissue)
Clinical relationsObesity, lipodystrophy

Adipose tissue, or fatty tissue, connective tissue consisting mainly of fat cells, specializes in synthesize and containing large globules of fat, within a structural network of fibres. It is found mainly under skin but also in deposits between muscles, in intestines and in their membrane folds, around the heart, and elsewhere. It is also found in bone marrow, where it imparts yellow colour; yellow marrow is most abundant in adults. Fat stored in adipose tissue comes from dietary fats or is produced in the body. Mammals have two different types of adipose: white adipose tissue and brown adipose tissue. White adipose, most common type, provides insulation, serves as an energy store for times of starvation or great exertion, and forms pads between organs. When muscles and other tissues need energy, certain hormones bind to adipose cells and trigger hydrolysis of triacylglycerol, resulting in release of energy - rich fatty acids and glycerol process know as lipolysis. The enzyme responsible for hydrolysis is lipase, which occurs in blood, certain gastrointestinal juices, and adipose tissue. Lipase is activated by hormones epinephrine, norepinephrine, glucagon, and adrenocorticotropin, which bind to adipocytes. White adipose tissue is also the source of a number of different hormones, which serve various roles in metabolism and endocrine function. Adipose - produce hormones adiponectin, leptin, and resistin are involved in energy metabolism, for example, whereas plasminogen activator inhibitor - 1 prevents dissolution of blood clots. Brown adipose, found mainly in newborn animals, generates heat and actually consumes energy. In humans, percentage of Brown adipose found in the body decreases with age. In other animals, however, particularly those that hibernate, it is found in adults and plays an important role in survival. Species that hibernate experience drop in body temperature and slowing of metabolism during winter dormancy, which allows them to conserve energy. Brown adipose, by consuming energy, releases heat, which is vital for awakening and emergence from dormancy. Brown adipose tissue is typically tan to red in colour. Its colour and heat - generating properties are imparted by the abundance of organelles know as mitochondria found in Brown fat cells. In humans, distribution of adipose tissue in the body can vary depending on sex. In general, men accumulate fat around the waist, and women tend to accumulate more fat around the hips than the waist. Geneticists have located distinct regions in the human genome that are associated with fat distribution, and several genes in particular appear to have greater influence on waist - to - hip ratio in women than in men. Because these genes are involved in regulating activities of fat cells, knowledge of their precise functions could provide insights into biological mechanisms underlying obesity, diabetes mellitus, and cardiovascular disease.


Adipose Tissue Function

The most important role of white adipocytes is energy storage. They store fat in the form of triglycerides inside their cytoplasmic lipid droplets, which help to maintain free fatty acid levels in the blood. For a long time, adipose tissue has been considered only as passive fuel reservoir. Now, it is also considered to be an endocrine organ which secretes several bioactive factors. The most important adipose tissue hormones include leptin and adiponectin. These biofactors circulate through organism and carry information to other metabolically active organs such as the liver, pancreas, muscle, and brain. These factors are of key importance in the pathophysiology of many metabolic disorders. Different localizations of adipose tissue have different roles in the human body. For example, abdominal fat has a different metabolic profile than the rest of fat in the body, and it has the biggest influence on inducing insulin resistance. Parietal fat has an important role in thermoregulation, while visceral fat provides cushion - like support for internal organs, protecting them from mechanical injuries. During reduced caloric intake, amount of parietal adipose tissue decreases, while visceral fat remains undiminished. In contrast to white, brown adipose tissue transforms chemical energy into heat. That way it prevents obesity, other metabolic disorders, and hypothermia. Ready to round up your knowledge of connective tissues? Try out our specially designed customizable quiz:

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Brown fat vs. white fat: Histological features

White fatCell morphology: Large unilocular lipid droplet pushing the organelles to the periphery of the cell Location: Hypodermis, bone marrow Appearance: A net of white polygonal structures
Brown fatCell morphology: Centrally positioned nucleus surrounded by multiple lipid droplets on the periphery of the cell Location: Retroperitoneum, deep cervical and supraclavicular regions of the neck, interscapular, paravertebral regions of the back and mediastinum Appearance: A net of cells filled with numerous empty vacuoles.
* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Blood

Brown fat vs. white fat: Histological features

White fatCell morphology: Large unilocular lipid droplet pushing the organelles to the periphery of the cell Location: Hypodermis, bone marrow Appearance: A net of white polygonal structures
Brown fatCell morphology: Centrally positioned nucleus surrounded by multiple lipid droplets on the periphery of the cell Location: Retroperitoneum, deep cervical and supraclavicular regions of the neck, interscapular, paravertebral regions of the back and mediastinum Appearance: A net of cells filled with numerous empty vacuoles.

Blood is considered connective tissue because it has matrix. Living cell types are red blood cells, also called erythrocytes, and white blood cells, also called leukocytes. The fluid portion of whole blood, its matrix, is commonly called plasma. The cell found in greatest abundance in blood is erythrocyte, responsible for transporting oxygen to body tissues. Erythrocytes are consistently the same size in species, but vary in size between species. Mammalian erythrocytes lose their nuclei and mitochondria when they are released from bone marrow where they are make. Fish, amphibian, and avian red blood cells maintain their nuclei and mitochondria throughout cell life. The principal job of erythrocyte is to carry and deliver oxygen to tissues. Leukocytes are white blood cells of the immune system involved in defending the body against both infectious diseases and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from multipotent cells in bone marrow know as hematopoietic stem cell.S Leukocytes are found throughout the body, including blood and lymphatic system. Different types of lymphocytes make antibodies tailored to foreign antigens and control production of those antibodies. Neutrophils are phagocytic cells that participate in one of the early lines of defense against microbial invaders, aiding in the removal of bacteria that has entered the body. Another leukocyte that is found in peripheral blood is monocyte, which give rise to phagocytic macrophages that clean up dead and damaged cells in the body, whether they are foreign or from host animal. Two additional leukocytes in the blood are eosinophils and basophils, both of which help to facilitate inflammatory response. Slightly - granular material among cells is cytoplasmic fragment of cell in bone marrow. This is called platelet or thrombocyte. Platelets participate in stages leading up to coagulation of blood to stop bleeding through damaged blood vessels. Blood has a number of functions, but primarily it transports material through the body to bring nutrients to cells and remove waste material from them.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Platelets (also called thrombocytes)

Platelets are derived from Bone Marrow megakaryocytes. In mice, platelets often cluster together but may occur AS individual platelets. In both species, diameter of platelets seen on blood smear ranges from 1 to 4 M. Platelet edges are irregular, with pointed filaments and tentacle - like protrusions. Cytoplasm stains light blue with small granules. No nucleus IS present. Although platelets tend to adhere to one another, clumping can also be indicative of suboptimal anticoagulation at time of blood collection. Platelets are crucial for thrombosis and hemostasis, and they respond to endothelial cell injury by activating, clumping, and providing catalytic surface for clotting factors. Platelets, or Thrombocytes, are vital to procoagulant events and contribute to the fibrinolytic process AS well. They are small, irregularly shaped clear cell fragments, which are derived from megakaryocytes. The average lifespan of platelet IS approximately 5 - 9 days. Platelets are at balance of bleeding or clotting events: When platelet numbers are low, excessive bleeding can occur, and when platelet numbers are high, thrombosis can occur. Disorders that reduce the number of platelets but typically cause thrombosis instead of bleeding are heparin - induce Thrombocytopenia and thrombotic thrombocytopenic purpura. Similar to endothelium, undisturbed platelet presents a nonthrombogenic surface. Important components of platelet physiology are surface adhesion protein complexes and platelet secretory granules: - granules, Lysosomes, and Dense granules. Contents of - granules include procoagulant and adhesive proteins such AS fibrinogen, fibronectin, thrombospondin, vWF, P - selectin, HMWK, platelet Factor 4, osteonectin, Factor V, 59 and Factor XI. 226 other - granule contents, 1 - antitrypsin, protein S, TFPI, and platelet inhibitor of Factor XI, are involved in anticoagulant activities. 227 - 229 - granule also contain proteins that meditate both pro - and antifibrinolytic processes. These proteins include plasminogen, 2 - antiplasmin, Factor XIII, and PAI - 1. 230 - 234 in unstimulated platelet, granule contents remain internalized and anionic phospholipid IS sequester in the inner leaflet of the plasma membrane. Prostaglandin I2 and nitric oxide release from endothelial cells, presence of CD39, and inability of normal plasma vWF to bind spontaneously to platelet surface are inhibitory mechanisms that keep platelets unactivated. 235 When vascular system IS perturb, platelet plug formation occurs in stages. During the first stage, platelets adhere and are activated by exposure to collagen and vWF and other matrix components. Cytoskeleton spreads and platelet - fibrinogen aggregates form and contents of granules are secrete. 236 - 238 activated platelets adhere to each other, endothelial cells, leukocytes, and components of the subendothelial matrix. The 239 phosphatidyl serine - rich internal face of cell membranes exposes and presents highly procoagulant surface to circulation. 240 in addition, activated platelets express specific receptors or binding sites for assembly of procoagulant multiprotein complexes. There are approximately 3000 Factor Va binding sites on the activated platelet membrane. 241 Factor Va forms part of the receptor for Factor Xa. Factor Xa IS also reported to bind to effector cell protease receptor - 1 molecules expressed on activated platelets.


Platelet Formation

Platelets are produced during hematopoiesis in a sub - process called thromopoiesis, or production of thrombocytes. Thrombopoiesis occur from common myeloid progenitor cells in bone marrow, which differentiate into promegakaryocytes and then into megakaryocytes. Megakaryocytes stay in bone marrow and are thought to produce protoplatelets within their cytoplasm, which are released in cytoplasmic extensions upon cytokine stimulus. Protoplatelets then break up into hundreds of platelets that circulate throughout the bloodstream, while the remaining nucleus of ruptured megakaryocyte is consumed by macrophages. Megakaryocyte and platelet production is regulated by thrombopoietin, hormone produced by the liver and kidneys. Thrombopoietin stimulates differentiation of myeloid progenitor cells into megakaryocytes and causes release of platelets. Thrombopoietin is regulated by a negative feedback mechanism based on platelet levels in the body, so that high levels of platelets result in lower levels of thrombopoietin, while low levels of platelets result in higher levels of thrombopoietin. Each megakaryocyte produces between 5 000 and 10 000 platelets before its cellular components are fully deplete. Altogether, around 10 to 11 platelets are produced each day in healthy adult.S The average lifespan of platelet is just 5 to 10 days. Old platelets are destroyed by macrophage phagocytosis in the spleen and by Kupffer cells in the liver. Up to 40% of platelets are stored in spleen as reserve, released when needed by sympathetically - induced splenic muscle contractions during severe injury.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

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