Biology 212Anatomy & Physiology I

Dr. Thompson

Blood

Biology 212Anatomy & Physiology I

Dr. Thompson

Blood

Blood:

Volume:

Components: Formed Elements:

Plasma:

pH: Buffered to remain stable

Erythrocytes

Primary Function –

Biconcave disks

No nucleus

4.5-5.5 million per microliter (cubic millimeter)4.5-5.5 billion per milliliter (cubic centimeter)Slightly higher in men

Hemoglobin

Each molecule: 4 large Globin proteins Each surrounding an iron- containing Heme Group

Oxygen

Erythrocyte formation = OccursDeveloping erythrocytes =

Erythropoiesis regulated

Erythrocytes also carry specific glycoproteins, or antigens, on their surfaces which are responsible for blood types

If transfused into person with incompatible blood type,

Erythrocytes normally survive

Trapped and destroyed

Iron

Leukocytes(White blood cells)

Five different types of cells

All formed

4,000 to 10,000 per cubic millimeter or4,000,000 to 10,000,000 per milliliter (cubic centimeter)

Each type has specific functions, but in general:Leukocytes function in body defenses by: Engulfing Directly Producing Secreting Secreting

Leukocytes

Grouped into twocategories

Abundant, distinct granules =

Few, small granules =

Granular Leukocytes

Named accordingto how these granules react toroutine lab stains("Wright's Stain"is most common)

The nucleus of each type also has a characteristic shape and/or density

Three types:

Neutrophils

.

Granules presentin cytoplasm butstain weakly withboth acidic andbasic stains

Nucleus

Also called

Eosinophils

Granules attractacidic stain eosin,therefore stainred or orange

Nucleus

Basophils

Granules attractthe basic stain hematoxylin,therefore stainblue or purple

Nucleus

Outside of circulation:

Agranular Leukocytes

Two unrelated types of leukocytes, neither of whichhas abundantgranules:

The nucleus of each type also has a characteristic shape and density

Monocytes

Nucleus

Stains

Cytoplasm

Outside of circulation:

Lymphocytes

Nucleus

Varying amounts of cytoplasm

Lymphocytes

Two types oflymphocytes withdifferent functionsin immune system,but they appear identical in blood:

All leukocytes formed in bone marrow, then enter blood

But:

Not particularly active when in the blood.

Most leukocytes are using the blood to get to other tissues and organs, where they differentiate and become active

Since they generally function outside of the circulatory system, primarily in the connective tissues of other organs,

All leukocytes can leave (and most can also reenter) the blood vessels by a process called

Therefore: All of the leukocytes, and the cells which they mature into, are normally found in connective tissues throughout the body

Platelets

Function

250,000 to 500,000 per cubic millimeter

or

250,000,000 to 500,000,000 per milliliter (cubic centimeter)

Platelets

Fragments of muchlarger cells,

which remain in

When blood vessels are damaged, the flow of blood through them must be stopped until the body can repair the injury.

This is called

It involves three processes in rapid sequence:

Vasospasm

When blood vessels are damaged, the flow of blood through them must be stopped until the body can repair the injury.

This is calledIt involves three processes in rapid sequence:

Formation of a Platelet Plug

- Under normal conditions, platelets do not stick to each other or to the walls of blood vessels

- As new platelets attach, they also

- When a blood vessel is injured, it releases chemicals which cause platelets to attach to each other and to the injured part of the vessel. This is

When blood vessels are damaged, the flow of blood through them must be stopped until the body can repair the injury.

This is called

It involves three processes in rapid sequence:

Formation of a Fibrin Blood Clot

- This involves a series of sequential chemical reactions in which the products of the first reaction serve as the catalysts of the second reaction, whose products are the catalysts of the third reaction, whose products are the catalysts of the fourth reaction, etc.

- This allows for a very rapid increase in the rate at which the clot forms.

- It also allows many chances to stop the process if it began by mistake or gets too far away from where the vessel was injured.

Formation of a fibrin blood clot involves 13 "clotting factors".

Each of these is the reactant for the next of these sequential reactions

Factor Synonyms

Factor I Fibrinogen

Factor II Prothrombin

Factor III Tissue Thromboplastin

Factor IV Calcium

Factor V Proaccelerin

Factor VI Labile Factor

Factor VII Prothrombin accelerator

Factor VIII Antihemophilic Factor A

Factor IX Antihemophilic Factor B

Factor X Stuart Factor

Factor XI Thromboplastin Antecedent

Factor XII Hageman Factor

Factor XIII Fibrin Stabilizing Factor

Formation of a fibrin blood clot involves 13 "clotting factors".

Each of these is the reactant for the next of these sequential reactions

Last reaction:

Once the fibrin clot has formed,

Over the next 30 to 60 minutes,

End result: Dense network of interconnected strands of fibrin with platelets, erythrocytes, and leukocytes trapped within it.

Over next few days, after vessel has time to repair itself: Clot is dissolved and removed by processcalled

Plasma protein

converted to activeenzyme

which dissolvesfibrin.