Table of contents (expand)
18. Blood. Formed elements of the blood. Erythrocytes and platelets
Blood is considered a modified type of connective tissue. Mesodermal is composed of cells and cell fragments (erythrocytes, leukocytes, platelets), fibrous proteins (fi-brinogen), and an extracellular fluid and proteins (plasma). It also contains cellular elements of the immune system as well as humoral factors.
The formed elements of the blood include erythrocytes, leukocytes, and platelets.
Erythrocytes, or red blood cells, are important in transporting oxygen from the lungs to tissues and in returning carbon dioxide to the lungs. Oxygen and carbon dioxide carried in the RBC combine with hemoglobin to form ox-yhemoglobin and carbaminohemoglobin, respectively.
Mature erythrocytes are denucleated, biconcave disks with a diameter of 7-8 mm. The biconcave shape results in a 20-30% increase in sur face area compared to a sphere.
Erythrocytes have a very large surface area: volume ratio that allows for efficient gas transfer. Erythrocyte membranes are remarkably pliable, enabling the cells to squeeze through the narrowest capillaries. In sickle cell anemia, this plasticity is lost, and the subsequent clogging of capillaries leads to a sickle crisis. The normal concentration of erythrocytes in blood is 3,5-5,5 million/mm 3 in women and 4,3-5,9 million/mm 3 in men. The packed volume of blood cells per total volume of known as the hematocrit. Normal hematocrit values are 46% for women and 41-53% for men.
When aging RBCs develop subtle changes, macropha-ges in the bone marrow, spleen, and liver engulf and digest them. The iron is carried by transferring in the blood to certain tissues, where it combines with apoferritin to form ferritin. The heme is catabolized into biliver-din, which is converted to bilirubin. The latter is secreted with bile salts.
Platelets (thromboplastids) are 2-3 mm in diameter.
They are a nuclear, membrane-bound cellular fragments derived by cytoplasmic fragmentation of giant cells, called megakaryocytes, in the bone marrow.
They have a short life span of approximately 10 days.
There are normally 150-000 platelets per mm400 of blood. Ultrastructurally, platelets contain two portions: a peripheral, light-staining hyalomere that sends out fine cytoplasmic processes, and a central, dark-staining granulomere that contains mitochondria, vacuoles, glycogen granules, and granules. Platelets seal minute breaks in blood vessels and maintain endothelial integrity by adhering to the damaged vessel in a process known as platelet aggregation. Platelets are able to form a plug at the rupture site of a vessel because their mem brane permits them to agglutinate and adhere to surfaces.
Platelets aggregate to set up the cascade of enzymatic reactions that convert fibrinogen into the fibrin fibers that make up the clot.
new words
mesodermal - mesodermal
erythrocytes - erythrocytes
platelets - platelets
carbon - carbon
dioxid - dioxide
span - span
light-staining - light staining
to aggregate - connect
Author: Elena Belikova
<< Back: Thoracic wall
>> Forward: Blood. Formed elements of the blood. Leukocytes
We recommend interesting articles Section Lecture notes, cheat sheets:
▪ Marketing. Lecture notes
▪ Accounting. Crib
▪ Internal illnesses. Crib
See other articles Section Lecture notes, cheat sheets.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
The existence of an entropy rule for quantum entanglement has been proven
09.05.2024
Quantum mechanics continues to amaze us with its mysterious phenomena and unexpected discoveries. Recently, Bartosz Regula from the RIKEN Center for Quantum Computing and Ludovico Lamy from the University of Amsterdam presented a new discovery that concerns quantum entanglement and its relation to entropy. Quantum entanglement plays an important role in modern quantum information science and technology. However, the complexity of its structure makes understanding and managing it challenging. Regulus and Lamy's discovery shows that quantum entanglement follows an entropy rule similar to that for classical systems. This discovery opens new perspectives in the field of quantum information science and technology, deepening our understanding of quantum entanglement and its connection to thermodynamics. The results of the study indicate the possibility of reversibility of entanglement transformations, which could greatly simplify their use in various quantum technologies. Opening a new rule ... >>
Mini air conditioner Sony Reon Pocket 5
09.05.2024
Summer is a time for relaxation and travel, but often the heat can turn this time into an unbearable torment. Meet a new product from Sony - the Reon Pocket 5 mini-air conditioner, which promises to make summer more comfortable for its users. Sony has introduced a unique device - the Reon Pocket 5 mini-conditioner, which provides body cooling on hot days. With it, users can enjoy coolness anytime, anywhere by simply wearing it around their neck. This mini air conditioner is equipped with automatic adjustment of operating modes, as well as temperature and humidity sensors. Thanks to innovative technologies, Reon Pocket 5 adjusts its operation depending on the user's activity and environmental conditions. Users can easily adjust the temperature using a dedicated mobile app connected via Bluetooth. Additionally, specially designed T-shirts and shorts are available for convenience, to which a mini air conditioner can be attached. The device can oh ... >>
Energy from space for Starship
08.05.2024
Producing solar energy in space is becoming more feasible with the advent of new technologies and the development of space programs. The head of the startup Virtus Solis shared his vision of using SpaceX's Starship to create orbital power plants capable of powering the Earth. Startup Virtus Solis has unveiled an ambitious project to create orbital power plants using SpaceX's Starship. This idea could significantly change the field of solar energy production, making it more accessible and cheaper. The core of the startup's plan is to reduce the cost of launching satellites into space using Starship. This technological breakthrough is expected to make solar energy production in space more competitive with traditional energy sources. Virtual Solis plans to build large photovoltaic panels in orbit, using Starship to deliver the necessary equipment. However, one of the key challenges ... >>
| Random news from the Archive Pedestrians are safer with robot cars
13.05.2012
Engineers from the Massachusetts Institute of Technology have found a way to solve the problem of communication between robot cars and pedestrians.
At present, many problems of automated transport have been practically solved: robots have learned to avoid obstacles, move in traffic, navigate on a map, and pass each other at intersections. However, it is impossible to introduce automatic road transport until the main problem - the safety of pedestrians - is solved.
Imagine the situation: you are standing on a pedestrian crossing and you see how a robot car rolls up to it, slowing down. Is it possible to transfer? Will the car stop or vice versa - it will rush forward? If a person is driving, you can understand whether he sees a pedestrian or not - in extreme cases, you can exchange gestures. With a robot, it's more difficult.
A group of engineers at MIT have developed a simple device that lets others know what's on the mind of a robot car. The system is equipped with several types of alarms. For example, when a car notices you, bright LED lights start flashing in different colors - from orange to red (depending on the distance). If the car does not see the pedestrian, then the lights are blue. Also, the robot-driver using the speakers can offer the pedestrian to cross the road or vice versa to stop. Thus, the robot can tell the pedestrian about his "plans" even more than a live driver.
|
Other interesting news:
▪ A new generation of transistor matrices from Toshiba
▪ Renewables have overtaken fossil fuels
▪ electronic fly
▪ iRiver P8 media player
▪ Wrist atomic clock
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Personal transport: land, water, air. Article selection
▪ article Looking for a person. Popular expression
▪ article What animals served the sailors as live canned food? Detailed answer
▪ Article Fennel vegetable. Legends, cultivation, methods of application
▪ article Automotive tachometer. Encyclopedia of radio electronics and electrical engineering
▪ article Submarine from grapes. Focus Secret
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese