Atonomiy of blood
Blood is a circulating tissue composed of fluid plasma
and cells redl, white blood cells, platelets. Medical terms related
to blood often begin in hemo- or hemato- from the Greek word "haima"
for "blood".The main function of blood is to supply nutrients
oxygen, glucose and constitutional elements to tissues and to remove
waste products such as carbon dioxide and lactic acid). Blood also
enables cells (leukocytes, abnormal tumor cells and different substancesamino
acids, lipids, hormone to be transported between tissues and organs.
Problems with blood composition or circulation can lead to downstream
tissue dysfunction
Anatomy of blood
Blood is composed of several kinds of these formed elements of
the blood constitute about 45% of whole blood. The other
55% is blood plasma, a yellowish fluid that is the blood's
liqui The normal pH of human arterial blood is approximately
7.40. Blood is about 7% of the human body weight [1].
Red blood cells or erythrocyt In mammals, these corpuscles
lack a nucleus and organelles, so are not cells strictly
speaking. They contain the blood's hemoglobin and distribute
oxygen. The red blood cells together with endothelial
vessel cells and some other cells are also marked by
proteins that define different blood types.
White blood cells or leukocytes , are part of the immune
system; they destroy infectious agents.
Platelets or thrombocytes are responsible for blood
clotting or coagulation and are involved in inflammation.
Blood plasma is essentially an aqueous solution containing
blood plasma proteins, and trace amounts of other materials.
Some components are:
blood clotting factors
immunoglobulins hormones various other proteins Together,
plasma and corpuscles form a non-Newtonian fluid whose
flow properties are uniquely adapted to the architecture
of the blood vessel
Physiology of bloodProduction and degradationBlood cells are produced
in the bone marrow; the process is termed hematopoiesis. The proteinaceous
component is produced overwhelmingly liver, while hormones are produced
by the endocrine glands and the watery fraction maintained by the
gut and the kidney.Blood cells are degraded by the spleen and the
Kupffer cells in the liver. The liver also clears proteins and amino
acids (the kidney secretes many small proteins into the urine.
Transport of oxygen
The amount of oxygen dissolved in blood is directly proportional
to the PO2 of the blood.The hemoglobin molecule is the primary transporter
of oxygen. 98.5% of the oxygen is chemically combined with the Hb.
Only 1.5% is physically dissolveSmall invertebratesIn some small
invertebrates like insects, oxygen is simply dissolved in the plasma.
Larger animals use respiratory proteins to increase the oxygen carrying
capacity. Hemoglobin is the most common respiratory protein found
in nature. Hemocyanin contains copper and is found in crustaceans
and mollusks. It is thought that tunicates might use vanabins proteins
containing vanadium for respiratory pigment bright green, blue,
or orange.In many invertebrates, these oxygen-carrying proteins
are freely soluble in the blood; in vertebrates they are contained
in specialized red blood cells, allowing for a higher concentration
of respiratory pigments without increasing viscosity or damaging
blood filtering organs like the kidneys.
Insects
In insects, the bloodis not involved in the transport
of oxygen.(Openings called tracheae allow oxygen from
the air to diffuse directly to the tissues). Insect
blood moves nutrients to the tissues and removes waste
products.
Transport of carbon dioxide
When systemic arterial blood flows through capillaries,
carbon dioxide diffuses from the tissues into the blood.
Some carbon dioxide is dissolved in the blood. Some
carbon dioxide reacts with hemoglobin to form carbamino
hemoglobin. The remaining carbon dioxide is converted
to bicarbonate and hydrogen ions. Most carbon dioxide
is transported through the blood in the form of bicarbonate
ions
Transport of hydrogen ionsSome oxyhemoglobin loses oxygen and becomes
deoxyhemoglobin. Deoxyhemoglobin has a much greater affinity for
H+ than does oxyhemoglobin so it binds most of the hydrogen ions.
Health and disease
Ancient medicineHippocratic medicine
considered blood one of the four humors As many diseases
were thought to be due to an excess of blood, bloodletting
and leeching were a common intervention until the 19th
century it is still used for some rare blood disorders)In
classical Greek medicine, blood was associated with
air, springtime, and with a merry and gluttonous personality.
It was also believed to be produced exclusively by the
liver.Diagnosis
Blood pressure and blood tests are amongst the most commonly performed
diagnostic investigations that directly concern the blood.
Pathology
See also blood diseasesProblems with
blood circulation and composition play a role in many
diseases.Wounds can cause major blood loss (see bleeding).
The thrombocytes cause the blood to coagulate, blocking
relatively minor wounds, but larger ones must be repaired
at speed to prevent exsanguination. Damage to the internal
organs can cause severe internal bleeding, or hemorrhage.
Circulation blockage can also create many medical conditions
from ischemia in the short term to tissue necrosis ngrene
in the long term.
Hemophilia is a genetic illness that causes dysfunction
in one of the blood's clotting mechanisms. This can
allow otherwise inconsequential wounds to be life-threatening,
but more co results in hemarthrosis, or bleeding into
joint spaces, which can be crippling.
Leukaemia (more often called leukemia is a group of
cancers of the blood-forming tissues.
Major blood loss, whether traumatic or not , as well
as certain blood diseases like anemia and thalassemia,
can require blood transfusion. Several countries have
blood banks to fill the demandble blood. A person receiving
a blood transfusion must have a blood type compatible
with that of the donor.
Blood is an important vector of infection. HIV, the
virus causes AIDS, is transmitted through contact between
blood, semen, or the bodily secretions of an infected
person. Hepatitis B and C are transmitted primarily
through blood contact. Owing to blood-borne infections,
bloodstained objects are treated as a biohazard.
Infection of the blood is bacteremia or sepsis. Malaria and trypanosomiasis
are blood-borne parasitic infections.
TreatmentBlood transfusion is the most direct therapeutic use of blood. It
is obtained from volunteers by blood donation. As there are different
blood types, and transfusion of the incorrect blood may cause seomplications,
crossmatching is to ascertain the correct type is transfused.Other
blood products administered intravenously are platelets, blood plasma,
cryoprecipitate and specific coagulation factor concentrates.Many
forms of medication (from antibiotics to chemotherap areered intravenously,
as they are not readily or adequately absorbed by the digestive
tract.As stated above, diseases are still treated by removing blood
from the circulation.
Mythology and religionDue to its importance to life, blood is associated with a large
number of beliefs. One of the most basic is the use of blood as
a symbol for family relationships; to be "related by blood"
related by ancestry or descendance, rather than marriage. This bears
closely to bloodlines, and sayings such as "blood is thicker
than water" and "bad blood", as well as "Blood
brother".
pean paganism
Among the Germanic tribes blood was used
during the sacrifices, the Blóts. The blood was
considered to have the power of its originator and after
the butchering the blood was sprinkled on the walls,
on the statues of the gods and on the participants themselves.
This act of sprinkling blood was called bleodsian in
Old English and the terminology was borrowed by the
Catholic Church becoming to bless and blessing. The
Hittite word for blood, ishar was a cognate to words
for "oath" and "bond", see Ishara.
In Judaism, blood cannot be consumed even in the smallest quantity
); this is reflected in the dietary laws. Blood is purged from meat
by salting and pickling.Other rituals involving blood are the covering
of the blood of fowl and game after slaughtering ( the reason given
by the Torah is: use the soul of every animal is [in] his blood"
, although from its context in Leviticus 3:17 it would appear that
blood cannot be consumed because it is to be used in the sacrificial
service (known as the korbanot), in the Temple in Jerusalem.Ironically,
Judaism has historically been the religion to be most affected by
blood libels.
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