Blood

Dr. Heba Kalbouneh Associate Professor of Anatomy and Histology

Blood - specialized form of connective tissue

- components:

- blood cells (several types)

- plasma (extracellular matrix)

Functions of Blood

• Transport nutrients and respiratory gases

• Transport waste products to organs and tissues where they can be recycled or released

• Transport hormones

• Transport immune cells throughout the body

• Helps regulate body temperature

Blood in the BODY

• 5-6 liters = 6 quarts

• pH of 7.35 -7.45

• Color is dependent on amount of Oxygen

– More oxygen = brighter the red

– Less oxygen = duller the red

Physical Characteristics

• Fluid

– Living 45%

• Cells (formed elements)

– RBC Erythrocytes (carry oxygen)

– WBC Leukocytes (immune)

– Platelets (clotting)

– Non living (Matrix) 55%

• Plasma (straw colored)

– 90% water

– 10 %

» Salt, nutrients, proteins (albumin), waste (CO2, ammonia,

urea), gases, hormones

HEMOCRIT: Ratio of

RBCs to Plasma

BUFFY COAT

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Figure 12-1

Serum = everything in plasma, minus the clotting factors

RBCs WBCs

Types 1 type 5 types

Not true cells True cells

Number Male: 4.5-5.5 million/mm3

female:4-5 million/mm3

4000-11000/mm3

Diameter 6-9um (7.5um) 6-20um

Life span 120 days Few days-years

Origin and

maturation

Bone marrow Bone marrow and lymphoid tissue

Shape Biconcave discs Spherical

Function Gas exchange Defense

Motility Non motile Motile

The Staining of Blood Cells

• Blood smears are usually stained with a mix of:

– Eosin, an acidic dye that stains pink to red

– Methylene blue, a basic dye that stains blue to purple

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Figure 12-3

Polychromatic stain: Giemsa, Wright. Leishman

Erythrocytes (RBCs)

• Small, biconcave discs

• Transport oxygen and CO2, cytoplasm is full of hemoglobin molecules

• Have no nuclei or organelles

• Pick up O2 at lung capillaries and release it at body tissue capillaries

• Survive for ~100-120 days in the circulation. Worn out RBCs are removed by macrophages of the spleen and liver.

During their maturation process, the erythrocytes extrude

their nuclei, and the mature blood cells enter the

bloodstream, without their nuclei

Erythrocytes can be used as a size reference for other cell

types

5 millions/mm3

Biconcave shape provides a large surface to volume ratio,

facilitating gas exchange

Flexible

Eosinophilia/acidophilia due to their

High content of hemoglobin (basic protein)

Sickle cell

Blood cell disorders

Leukocytes

• Originate in the bone marrow and released continuously into the blood

• Travel in bloodstream but function mainly outside of the bloodstream (in loose CT)

• 5 types organized into 2 groups – Granulocytes

• Neutrophils

• Eosinophils

• Basophils

– Agranulocytes

• Lymphocytes

• Monocytes

Granulocytes Agranulocytes

Consequently, most leukocytes are concentrated in the

connective tissue of different organs

Leukocytes perform their major functions outside

the blood vessels

Leukocytes form a mobile army that helps protect the body from damage

By bacteria, viruses, parasites, toxins and tumor cells

Specific granules

(secondary)

Azurophilic granules

Lysosomes

(primary)

Granulocytes

• Cytoplasmic granules (containing enzymes or

chemicals) makes cytoplasm look grainy

• Non-spherical nuclei with lobes

• All are phagocytic; they engulf and consume foreign

cells and material

• 3 main types

Large granules, Red Large granules, blue

Small granules, pale pink/

salmon pink

Basophil

EOSINOPHIL

Neutrophil

Granulocytes: Neutrophils

• Up to 5 lobes in nucleus connected by “threads” of nuclear material (polymorphs)

• light pink cytoplasm

• Called neutrophils because cytoplasm takes up red (acidic) and blue (basic) stains equally

• Specialized for responding to bacterial invasions- Acute infection- acute pyrogenic infections

• Specific granules

(secondary)

- Lysozyme

- Phagocytin

(bactericidal)

- Lactoferrin

(bacteriostatic)

- Collagenase

• Azurophilic granules

(primary)

- Myeloperoxidase

- Acid hydrolase

- Defensins

Polymorphs

Pus cells

Myelocytes

Microphage

Pus is pyrogenic

Few organelles

Neutrophilia

Neutropenia

Granulocytes: Basophils

• Rarest leukocyte – might not see these under the microscopes

• Usually have bi-lobed, S-shaped nuclei but their granules often makes it hard to see

• Has large granules that stain dark purple in basic dyes (basophil = basic loving)

• Granules contain histamine and other molecules that mediate inflammation in allergic reactions and parasitic infections

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Granulocytes: Eosinophils

• Usually have bi-lobed nuclei

connected by a short “thread” of

nuclear material

• Large cytoplasmic granules,

which stain red with the acidic

eosin dye (eosinophil = eosin

loving)

• Help in ending allergic reactions

and in fighting parasitic

infections

Specific granules:

-Crystalloid

-Two parts:

Externum (pale): contains histaminase and sulfatase

Internum (dark): contains basic protein to kill parasites

Neutrophil Eosinophil Basophil

Percentage

(WBCs)

60-70 % 1-4% 0-1%

Size 10-12 um 10-14 um 10-12 um

Life span 3-4 days in

c.t

Few days Few days

Nucleus 2-5 lobes 2 lobes

(horseshoe)

Irregular

(s-shaped)

Phagocytic

activity

Most Least

Motility Most Least

General features

-Spherical in blood stream, irregular in c.t

-Highly motile with different shapes due to their amoeboid movement

-Leave blood stream by migrating between the endothelial cells by

a process called diapedesis

Agranulocytes

• Granules in cytoplasm are absent or too small to

see (nonspecific granules)

– Cytoplasm appears clear blue

• 2 types based on structure (not cell lineage):

– Lymphocytes

– Monocytes

Agranulocytes: Lymphocytes

• Round nucleus occupies most of cell volume

• Cytoplasm is light blue

• T cells

– Has different types, some directly kill foreign or infected cells; others activate phagocytes to destroy microbes

• B cells

– Differentiate into plasma cells

– Secrete antibodies that bind to specific antigens and mark them for destruction by phagocytic cells

Long term immunity

Cell mediated immunity

Humoral immunity

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Lymphocyte

Natural killer cells

(NULL Lymphocyte)

T Lymphocyte B Lymphocyte

Cytotoxic

Helper

Memory cell Plasma cell

Suppressor

Large Small

Suppresses immune response to self Ag

Suppresses immune response of T and B lymphocytes

Kill virus-infected

and damaged cells

Help cytotoxic T

cells and B cells in

their immune

functions

Produces antibodies

Morphologically they can be classified into small (6-8 m) medium (10-14

m) and large (> 18 m).

Different types express specific cell surface proteins

Agranulocytes: Monocytes

• Largest leukocytes

• Clear blueish cytoplasm (frosted glass appearance) & a large C-shaped purple nucleus

• Larger proportion of cytoplasm than lymphocytes

• Travel through bloodstream to reach connective tissues, where they transform into macrophages (large phagocytic cells)- Chronic infections

Never Let Monkeys Eat Bananas

Most common to least

Thrombocytes (Platelets) • Small non-nucleated

cytoplasmic fragments

• Broken off from larger cells called megakaryocytes

• Number: 200,000-400,000/mm3

• Diameter: 2-4 um

• Lifespan 5-10 days

• Aids in clotting by plugging tears in vessel walls

• Control the bleeding by plugging the defects in blood vessels and activating blood clotting cascades

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Platelete has 2 zones

Outer pale basophilic

(clear) perpheriral zone:

hyalomere

Central dark granular

zone: granulomere

Granulomere: contains granules and

organelles

Alpha granules: clotting factors,

growth factors

Dense (delta) granules: serotinin, ATP,

ADP

Lambda granules: lysosomes

Hyalomere: contains cytoskeleton

Microtubule: maintain shape

Actin filaments: help contractions of

platelets and squeezing

Membrane channels

Open canalicular system

Dense tubular system

Have thick glycocalyx

Their main function is to continually monitor the vascular

system and detect any damage to the endothelial lining of

the vessels. If the endothelial lining breaks, the platelets

adhere to the damaged site and initiate a highly complex

chemical process that produces a blood clot

Thus preventing blood loss

IDENTIFY ?

MONOCYTE

Lymphocyte

Platelets and Neutrophil

Blood Cell Formation (Hematopoiesis)

• Begins during embryonic development

– yolk sac, liver, spleen, bone marrow

• Continues throughout life

– only in bone marrow after 28 weeks

• After birth, all blood cells originate in bone

marrow

The red bone marrow is a highly cellular structure and

consists of:

Hemopoietic stem cells

(the precursors of different blood cells) supported by a

reticular tissue.

As the individual ages and becomes an adult, the

red marrow is found primarily in the flat bones of the

skull, sternum and ribs, vertebrae, and pelvic

bones. The remaining bones, primarily the long bones

in the limbs of the body, gradually accumulate

fat, and their marrow becomes yellow. Consequently,

they lose the hemopoietic functions.

Myeloid: Erythroid

5:1

Granulocytes -Neutrophils

-Basophils

-Eosinophils

Erythrocytes

Megakaryocytes

Monocytes

T lymphocyte

B lymphocyte

Natural killer cells

Erythropoiesis: the process which produces erythrocytes

Granulopoiesis: the process which produces granulocytes

Thrombopoiesis: the process which produces thrombocytes

Lymphopoiesis: the process which produces lymphocytes

Monocytopoiesis: the process which produces monocytes

Blood Cell Formation (Hematopoiesis)

Myeloid stem cells Lymphoid stem cells

Hematopoietic stem cell

Reticulocyte

Are immature red blood cells (last stage)

The cell has extruded its nucleus, but is still

capable of producing hemoglobin

Supravital dye: precipitation of reticulum in the

cytoplasm

Normally, only about 1% of all red blood cells in

the bloodstream are reticulocytes

They circulate for about 1-2 days before

developing into mature red blood cells

An increase in reticulocytes ---- blood loss

(hemorrhage)

Reticulocytes

Are immature neutrophils

Band cell differentiates into mature granulocyte

(neutrophil)

Band cell is characterized by having a nucleus

which is curved (band shaped), but not lobar

An increase in band neutrophils: acute infection

Band cells

Band cell is almost a mature neutrophil, just

doesn’t have a segmented nucleus yet

Lymphopoiesis

Lymphoid stem cells

Hematopoietic stem cell

lymphoblast

Prolymphocyte

B Lymphocyte

T Lymphocyte Natural killer lymphocyte

Thymus

BM

Directly into blood

BLOOD TYPES

UNIVERSALITY

BLOOD

TYPE

SURFACE

PROTEIN

ANTIBODY RECEIVE

FROM

A A B A or O

B B A B or O

AB A B None A, B, AB, O

Universal

acceptor

O None A, B 0

Universal

Donor

1- Basophilia (deep blue): affinity for basic

dye methylene blue

(DNA, RNA (RIBOSOMES))

2- Eosinophilia (red): affinity for acidic dye

eosin

(hemoglobin within erythrocyte)

3- Neutrophilia (salmon pink/liliac):

characteristic of the specific

cytoplasmic granules of neutrophil

4- Azurophilia (purple): affinity for azure dyes,

typical of lysosomes

Useful links (optional)

http://highered.mheducation.com/sites/dl/free/0072507470/291136/t_cell_depe

ndent_antigens.swf

http://highered.mheducation.com/sites/dl/free/0072507470/291136/Cytoxic_T_c

ell_activity_against_target_cells.swf

http://highered.mheducation.com/sites/dl/free/0072507470/291136/immRespon

se.swf