Introduction to blood
Introduction to blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the circulatory system is also known as peripheral blood, and the blood cells it carries, peripheral blood cells.
Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume),[3] and contains proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood.[citation needed] The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets (also called thrombocytes).[4] The most abundant cells in vertebrate blood are red blood cells.[5] These contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas thereby increasing its solubility in blood.[6] In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma.
Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated.[7]
Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin.[8] Insects and some mollusks use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen.
Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system.
Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals with lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.
Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Greek word αἷμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue,[9] given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.
BLOOD VOLUME
Blood accounts for 7% of the human body weight, with an average density around 1060 kg/m3, very close to pure water's density of 1000 kg/m3. The average adult has a blood volume of roughly 5 litres (11 US pt) or 1.3 gallons, which is composed of plasma and formed elements.
Composition:
Plasma = 55% of volume
Formed elements = 45%
* Formed elements = RBC’s, WBC’s, Platelets
BIOPHYSICAL CHARACTERISTICS OF THE BLOOD
1) Specific gravity
Blood - 1056 (152-1063) kg/m3
- plasma 1027
- red blood cells 1090
2) Viscosity
- water = 1; blood 4-5.4x more
Syndrome of hyperviscosity – impairment of microcirculation, hypoxia,...
3) Blood pH is regulated to stay within the narrow range of 7.35 to 7.45, making it slightly basic.
4) An average-sized man has about 12 pints of blood in his body, and an average-sized woman has about nine pints.
WHOLE BLOOD
https://medstudyworld.blogspot.com/2021/12/whole-blood.html
extra notes
Did you know?
The body has 60,000 miles of blood vessels. This is long enough to circle the globe more than twice.
It takes a red blood cell less than a minute to move from the heart, through the body, and back to the heart.
Red blood cells live for around 120 days.
Every second your body makes about two million red blood cells.
An average adult heart pumps about five tablespoons of blood per beat.
https://www.britannica.com/science/blood-biochemistry
https://www.austincc.edu/sziser/Biol%202404/2404LecNotes/2404LNExIV/Blood%20&Hematology.pdf
https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/
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