Blood is 55% Plasma (Liquid)

The plasma portion of blood is:

• 91% Water

• 2 % Salts, gases (O2, CO2),

nutrients, wastes,

hormones, vitamins, etc…

• 7% Proteins (ie: clotting

proteins, albumin,

immunoglobulins…)

Maintains blood volume

Transports molecules

Blood is 45% Formed Elements (Solids)

The solid portion of blood is:

Red Blood Cells

(RBCs) Erythrocytes

White Blood Cells

(WBCs) Leukocytes

Platelets Thrombocytes

Blood

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Structure of Red Blood Cells

Red Blood Cells (RBC’s)

• No nuclei

• Transport CO2 and O2 and H+

(acts like a buffer)

• Biconcave discs

• Live for ~ 120 days (4 months)

• Contain hemoglobin molecules,

carbonic anhydrase, and antigens

• Made in the red bone marrow

Erythrocytes

Transports oxygen as oxyhemoglobin (bright red)

Hb + O2 ------------------------------- HbO2

Transports carbon dioxide as carboxyhemoglobin

Hb + CO2 ------------------------------- HbCO2

Transports hydrogen ions as reduced hemoglobin (thus

acting as a buffer)

Hb + H+ ------------------------------- HHb

Note: fetal hemoglobin has a

greater affinity for oxygen than

maternal hemoglobin!

Hb attaches to oxygen when

it’s cool, high pH, and low

pressure (ie: at the lungs)!

Do NOT copy – FYI for later

White Blood Cells

(Leukocytes)

• Formed in bone marrow & lymph tissue

• WBC’s can squeeze out of blood vessels to attack invaders.

• Role: Fight Infection - by producing

antibodies OR through phagocytosis

of pathogen

White blood cell squeezes out of

blood vessel to attack invaders

WBCs Differ from

RBCs:

• have nucleus

• Larger & fewer in

number

1. Basophiles – release histamine when damaged which causes capillaries

to dilate and release fluid – fluid leaks into tissues =

swelling

2. Neutrophils

3. Eosinophils

4. Monocytes – becomes macrophages (really large) at site of infection

(inflammatory response)

5. Lymphocytes = T-cells →triggers immune response

= B-cells → release antibodies

5 Types of WBCs

Phagocytic

Platelets

(Thrombocytes)

• They are just fragments of

cells (irregular shape) with

no nuclei

Platelets • We produce ~ 200

billion/day

• Made in bone marrow

• Aid in blood clotting

• Recognize micro tears in blood vessels

& bind together to form a blood clot

Clot formation:

After injury, an enzyme is secreted to change a

blood protein called fibrinogen (soluble) to fibrin

(insoluble protein)

platelets + fibrinogen “fibrin”

(in plasma)

Fibrin clumps at injury site & partially blocks leak

Fibrin threads trap blood cells to clot the injured

site

BLOOD TYPES

Antigens/Antibodies & Blood Type

Antigens and Antibodies

have different but related

functions!

Antigen: an identification glycoprotein on a RBC

• 2 kinds of antigens on human RBC's: A and B

• Therefore, 4 possible blood types:

Antigen A Type A blood

Antigen B Type B blood

Antigens A & B Type AB blood

No Antigens Type O blood

• Made by the WBC cells in the body

• Will bind to foreign proteins with foreign antigens

• This causes AGGLUTINATION = clumping

• WBC’s will then destroy the agglutinated cells

Antigen (Foreign)

+ Antibody (Yours)

(Agglutinization)

Y + = Y

Y Y

Y Y

Y Y Y Y Y

Antibody: a protein designed to combat any

foreign protein

Our blood has antibodies that are opposite to

the antigens we have on our RBC’s.

So we don’t attack our own blood!

WHY?

This is what it ‘looks’ like

Type A has B antibodies

Type B has A antibodies

Type O has A and B antibodies

Type AB has No antibodies

• Therefore blood transfusions are tricky:

introducing foreign antigens can lead to…

DEATH

Note: Antibodies are REMOVED from donated

blood – they cannot cause agglutination

Blood Type A B AB O

A

B

AB

O

yes

clumps

yes

clumps

clumps

yes

yes

clumps

clumps

clumps

yes

clumps

yes

yes

yes

yes

Blood donor

The Rh factor is another antigen that may be present

on the RBC. The presence of this antigen plays a role

in childbirth.

•If you are Rh+ you have the antigen and don’t have the

‘D’ antibodies. (85% of Caucasions are Rh+)

•If you are Rh – you don’t have the antigen. You don’t

normally have the ‘D’ antibodies, but can make them if you

are exposed to Rh antigens.

Rh + NO ANTIBODIES

Rh - HAS ANTIBODIES, BUT

ONLY WHEN EXPOSED

TO Rh+ BLOOD

Do NOT copy

•If Rh antigens are mixed with Rh antibodies,

agglutination occurs.

Do NOT copy

Donor Recipient

Anti-Rh

Antibodies

in Recipient's

Blood

Rh + Rh -

Rh - Rh +

Will Produce

anti-Rh

Antibodies

Will Not

Produce

anti-Rh

Antibodies

Do NOT copy

Rh -

Blood

Rh +

Blood

WHY ELSE IS THIS IMPORTANT?

•If an Rh- mother can has an Rh+ baby,

complications can occur with a second

pregnancy.

•Normally, the mother / fetal blood does not

mix or cross the placenta.

•However, at birth, there is usually some

mixing, and the mother will begin to produce

Rh antibodies in response to the Rh

antigens on the baby's Rh+ RBC's.

•There is no danger for either the mother or

the first baby.

These antibodies will agglutinate the baby's blood.

BUT…If the mother becomes pregnant with

another Rh+ baby, the mother’s antibodies

(made during the birth of the 1st child) are small,

and can cross the placenta.

This will cause the baby to

die / be still born

(Erythroblastosis).

Do NOT copy

How can this be prevented?

When the first Rh+ baby is born, doctors can destroy the

Rh+ blood cells in the mother's plasma before the

mother has time to make the Rh antibodies.

An injection of Rh immune globulin injection (RhoGAM)

does this.

Do NOT copy

THE END of blood & blood

types