Plasma Composition
By ScholarRx
Updated March 9, 2021
access_time8 min
Learning Objectives (3)
After completing this brick, you will be able to:
● Define blood plasma and explain its importance and function.
● 1
● Compare and contrast the contents of plasma and serum.
● 2
● Understand how plasma components are used in medicine.
● 3
cableCASE CONNECTION
Over the chaos and loud conversation in the emergency department,
you hear your resident yell, “We need four more units of packed red
cells and six units of fresh frozen plasma to room 5. STAT!” All the
commotion centers on DW, a 65-year-old man transferred by
helicopter from a local hospital where he was initially evaluated and
treated for a massive GI bleed secondary to a large duodenal ulcer.
He received eight units of packed RBCs at the other hospital. DW’s
hemoglobin now is very low, and he is unresponsive. His blood
pressure is 88/56 mm Hg and heart rate 110/min.
Besides ordering an emergent consult to GI and the packed RBCs for
transfusion, why did your resident call for fresh frozen plasma in DW’s
,condition? Consider your answer as you read, and we’ll revisit at the
end of the brick.
GO TO CONCLUSION arrow_downward
What Is Plasma?
When you hear the word blood, what do you picture in your mind?
Most likely, your brain conjures up an image of thick, red liquid. But
what would blood look like if you removed all the red cells? You’d be
left with a murky yellowish liquid that would clear up once you
removed the white cells and platelets. This lovely, clear, straw-
yellow, liquid portion of blood is known as plasma.
Normal Blood Composition
Blood is made up of four main components: red blood cells (RBCs),
white blood cells (WBCs), platelets, and plasma. Almost half (45%)
of the blood volume consists of the cellular components; plasma is the
remaining 55%. If you centrifuge a tube of blood, the cells and plasma
separate and form distinct layers, making it easy to visualize their
relative proportions (Figure 1).
,Figure 1
Credit: ©ScholarRx
The RBCs are heaviest and land at the bottom of the tube. A “buffy
coat” consisting of WBCs and platelets will be found in the middle.
Plasma is the component that is liquid and found at the top of a
centrifuged tube of blood; composed of ~92% water, it surrounds all
the other cellular components to help carry them throughout the body.
, The high water content encourages smooth blood flow and decreases
the blood’s viscosity, or thickness. Severe dehydration can deplete the
plasma’s water, causing a variety of problems. Some of these issues
include hypotension and electrolyte imbalances.
Plasma Composition
Despite being mostly water, blood plasma actually contains tons of
important protein, molecules, and dissolved salts. About 7% of
plasma is composed of proteins and about 1% is composed of
inorganic salts like sodium, potassium, calcium, carbonate, and
phosphate.
The three important types of proteins found in plasma are albumin,
immunoglobulins, and fibrinogens. The majority of the protein
portion of plasma is albumin, which allows plasma to be a key
regulator of blood osmolality. Albumin concentration is the main
force drawing water from the tissues into the blood. For example, if
albumin is leaking into the tissue, water will follow the albumin in an
effort to dilute it. This leaking of fluid into the tissue is known as
edema. We will see albumin come into play in a variety of disorders
throughout our study of the human body. Albumin is also an
important carrier protein for calcium, hormones, and drugs. The next
protein component is globulins, aka antibodies, which are the immune
system’s circulating proteins that help fight infections. Plasma also
holds the clotting factors, the largest one being fibrinogen.
Plasma Functions
By ScholarRx
Updated March 9, 2021
access_time8 min
Learning Objectives (3)
After completing this brick, you will be able to:
● Define blood plasma and explain its importance and function.
● 1
● Compare and contrast the contents of plasma and serum.
● 2
● Understand how plasma components are used in medicine.
● 3
cableCASE CONNECTION
Over the chaos and loud conversation in the emergency department,
you hear your resident yell, “We need four more units of packed red
cells and six units of fresh frozen plasma to room 5. STAT!” All the
commotion centers on DW, a 65-year-old man transferred by
helicopter from a local hospital where he was initially evaluated and
treated for a massive GI bleed secondary to a large duodenal ulcer.
He received eight units of packed RBCs at the other hospital. DW’s
hemoglobin now is very low, and he is unresponsive. His blood
pressure is 88/56 mm Hg and heart rate 110/min.
Besides ordering an emergent consult to GI and the packed RBCs for
transfusion, why did your resident call for fresh frozen plasma in DW’s
,condition? Consider your answer as you read, and we’ll revisit at the
end of the brick.
GO TO CONCLUSION arrow_downward
What Is Plasma?
When you hear the word blood, what do you picture in your mind?
Most likely, your brain conjures up an image of thick, red liquid. But
what would blood look like if you removed all the red cells? You’d be
left with a murky yellowish liquid that would clear up once you
removed the white cells and platelets. This lovely, clear, straw-
yellow, liquid portion of blood is known as plasma.
Normal Blood Composition
Blood is made up of four main components: red blood cells (RBCs),
white blood cells (WBCs), platelets, and plasma. Almost half (45%)
of the blood volume consists of the cellular components; plasma is the
remaining 55%. If you centrifuge a tube of blood, the cells and plasma
separate and form distinct layers, making it easy to visualize their
relative proportions (Figure 1).
,Figure 1
Credit: ©ScholarRx
The RBCs are heaviest and land at the bottom of the tube. A “buffy
coat” consisting of WBCs and platelets will be found in the middle.
Plasma is the component that is liquid and found at the top of a
centrifuged tube of blood; composed of ~92% water, it surrounds all
the other cellular components to help carry them throughout the body.
, The high water content encourages smooth blood flow and decreases
the blood’s viscosity, or thickness. Severe dehydration can deplete the
plasma’s water, causing a variety of problems. Some of these issues
include hypotension and electrolyte imbalances.
Plasma Composition
Despite being mostly water, blood plasma actually contains tons of
important protein, molecules, and dissolved salts. About 7% of
plasma is composed of proteins and about 1% is composed of
inorganic salts like sodium, potassium, calcium, carbonate, and
phosphate.
The three important types of proteins found in plasma are albumin,
immunoglobulins, and fibrinogens. The majority of the protein
portion of plasma is albumin, which allows plasma to be a key
regulator of blood osmolality. Albumin concentration is the main
force drawing water from the tissues into the blood. For example, if
albumin is leaking into the tissue, water will follow the albumin in an
effort to dilute it. This leaking of fluid into the tissue is known as
edema. We will see albumin come into play in a variety of disorders
throughout our study of the human body. Albumin is also an
important carrier protein for calcium, hormones, and drugs. The next
protein component is globulins, aka antibodies, which are the immune
system’s circulating proteins that help fight infections. Plasma also
holds the clotting factors, the largest one being fibrinogen.
Plasma Functions
