blood components
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BLOOD COMPONENTS
Overview There are 4 main components within
blood that we are concerned with:
1. Red Blood Cells2. White Blood Cells3. Blood Plasma4. Platelets
Blood Blood = a collection of specialized cells
that perform specific functions for an organism
Even though it appears liquid, blood is considered a tissue like skin, muscle, bone, etc
Consists of two distinct elements:1. Fluid plasma portion2. Solid or “formed” portion
Blood About 55% of blood is
plasma, Water Dissolved gases Proteins, sugars, vitamins,
minerals, and waste products.
The remaining 45% of the blood is composed of cells White Blood Cells Red Blood Cells
Red Blood Cells (RBCs) Also called erythrocytes
Make up 44% of the total volume of your blood. The average male has 5.5 million RBCs/mL of
blood the average female has 4.5 million RBCs/mL of
blood
The shape of a RBC is described as a biconcave disk
RBCs The red blood cell is specialized for oxygen
transport Only 2% of the oxygen that enters the blood stream
is transported by the fluid portion of the blood. The remainder is transported by RBCs
these cells vastly increase the oxygen carrying capacity of the blood.
A mature red blood cell has no nucleus but is packed with 280 million molecules of hemoglobin an iron-containing molecule Has several binding sites for oxygen
Hemoglobin Hemoglobin is a pigment molecule, which gives
blood its red color (when bound to oxygen) in humans
RBCs Hemoglobin is specially designed to
perform two opposite functions: Pick up dissolved oxygen from the lungs
and carry it to the cells of the body. Release this oxygen, but only in the
presence of the cells that require it.
This ability is dependent on the structure of hemoglobin
RBCs A hemoglobin molecule contains four iron (Fe) atoms
Each represents a separate binding site (heme group) When the concentration of oxygen is high, each heme
group may form a loose bond with oxygen e.g. In the capillaries of the lungs
When the concentration of O2 is low, this loose bond is broken e.g. in the cells of working muscles
Theoretically, four molecules of oxygen can become attached to one molecule of hemoglobin.
In reality, not all of the possible heme positions will be occupied by oxygen.
Capillaries in the Lungs
Working muscle cells in the body
Oxygen binds to Hb
Oxygen is released from Hb
White Blood Cells (WBCs)
also called leucocytes make up only 1% of your total blood volume.
may increase to more than double normal levels, however, when your body is fighting an infection.
Have a number of different roles that help protect the body from disease-causing agents, or pathogens.
In contrast to red blood cells, all white blood cells have nuclei and appear colourless.
WBCs There are several types of WBCs
1. Macrophages can pass through the walls of the capillaries
to engulf and digest pathogens (phagocytosis = “cell eating”)
part of the body’s innate immune response which is the body’s generalized, automatic
response to infection.
WBCs2. Lymphocytes are non-phagocytic cells involved in the body’s acquired immune
response the body’s ability to recognize and fend off specific
pathogens.
There are two main types of lymphocytes: T cells & B cells Each contribute a specific part of the response that
allows the body to become immune to certain toxins.
WBCs In addition to their role in fighting
disease, lymphocytes can (under particular conditions) undergo changes to become a variety of cell types. Converted into red blood cells the bone
marrow Help construct different kinds of connective
tissue fibres throughout the body.
Platelets Also called thrombocytes They are only fragments of cells that were
created when larger cells in the bone marrow break apart.
Do not contain a nucleus Break down quickly in the blood
each platelet lasts only about a week to 10 days Platelets play an important role in clotting
blood and preventing excessive blood loss after an injury
Blood Clotting Process is not completely understood Clotting is first triggered by the injury.
Does not occur until a blood vessel is brokenA. Platelets are attracted to the site of the damaged
vessels and combine with other clotting agents in the plasma
produces the enzyme thromboplastinB. Thromboplastin reacts with prothrombin to produce
thrombin.C. Thrombin is an enzyme that reacts with a plasma
protein to produce fibrin. Insoluble, forms a mesh of strands that traps escaping
blood and forms the clot
Blood Plasma
The fluid portion of the blood in which the blood cells are suspended.
Also contains substances that play an important role in maintaining the body’s well-being. Fibrinogen (blood clotting) Serum albumin: maintaining the blood volume and blood
pressure. Serum globulin: protein antibodies to defend against
disease. Plasma also plays a role in the transport of carbon
dioxide in the blood. carried in the plasma from tissues to the lungs for gas
exchange.
Plasma Serum = The straw-coloured liquid
that remains when the clotting agents are removed contains cellular nutrients, hormones,
electrolytes, enzymes, hormones, antibodies, and waste materials.
Serum from an animal or a person immune to a particular disease can be injected into a patient to provide temporary immunity from that disease.
Summary Using a full page, copy table 9.2 into
your notebook For each component of blood you are
responsible for knowing: the relative amounts (% or cells per mL
blood) sizes compared to each other lifespan important function(s)
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