histology of connective tissues

Connective Tissues

Embryonic Connective

Tissues

Mesenchymal Connective Tissue

Mucoid Connective Tissue

Loose Connective Tissues

Areolar Connective Tissue

Adipose Tissue Reticular

Connective Tissue

Dense Connective Tissues

Dense Regular Connective Tissue

Dense Irregular Connective Tissue

Elastic Connective Tissue

Connective Tissues of Special

Purposes

Cartilage

Hyaline Cartilage Fibrocartilage Elastic Cartilage

Bone Tissue Blood

Histology of Connective Tissues

Embryonic Connective Tissues

Types Histological Findings Specialized Cells Histological Appearance

Mesenchyme

Location

Under the skin of

developing feotus

Around blood vessels in

the adult

Function

Form other type of CT

Irregular shaped

mesenchymal cells

Ground substance of

reticular fibers

Mesenchymal cells

Mucous Connective

Tissue

Location

Umbilical cord

Function

Support

Widely scattered Fibroblasts

o Spindle-shaped cells

Ground substance is

viscous, jelly-like

appearance (Wharton’s

jelly)

o Containing Collagenous

fibers

Fibroblast

Loose Connective Tissues

Types Histological Findings Specialized Cells Histological Appearance Areolar Connective Tissues

Location

Subcutaneous layer of skin

Lamina Propia of mucous

membrane

Around

o Blood vessels

o Nerves

Function

Strength

Elasticity

Support

Interspersed cells

o Fibroblast

o Adipocytes

o Macrophages

o Plasma cells

o Mast cells

Semi fluid ground substances

with fibers

o Collagen (reddish in color and

thick)

o Elastin (darkly stained)

o Reticular

Subcutaneous of

skin

o Histiocytes

Lungs

o Alveolar

macrophages

Nerves

o Microglial cells

Adipose Tissue

Location

Subcutaneous layer of skin

Around heart and kidneys

Yellow marrow

Behind eye balls

Pading around joints

Function

Reduces heat loss

Energy reservoir

Supports and protects

Adipocytes

o Large

o Centrally located

droplects of fat

o Peripherally located

nuclei

Adipocytes

Reticular Connective Tissue

Location

Stroma

Red marrow

Reticular lamina of

basement membrane

Around blood vessels

Function

Supports

Barrier

Production of myeloid

lineage

Networks of interlacing

Reticular fibers with

Reticular cells

Numerous Myeloid Stem

Cells (stained darkly red)

Reticular cells

Dense Connective Tissues

Types Histological Findings Specialized Cells Histological Appearance Dense Regular

Connective Tissue

Location

Tendon and ligaments

Aponeurosis

Function

Provides strong

attachment between

various structures

Consists of numerous fibers

which is arranged in

ORDERLY manner

o Collagenous fibers

With Fibroblasts in between

arranged in rows

(Fibrocytes in mature

tendon)

Fibroblasts

Dense Irregular

Connective Tissue

Location

Fascia

Periosteum

Pericardium

Perichondrium

Heart valves

Function

Provides strength

Consist mostly Collagenous

fibers arranged

DISORDERLY

With RANDOMLY located

Fibroblasts

Fibroblasts

Elastic Connective Tissue

Location

Wall of Elastic artery

Respiratory tracts

Vocal cords

Wavy bands of Elastic fibers

(darkly stained) and

branching in all directions

Fibroblasts may present in

between

Fibroblasts

Connective Tissues with Specialized Functions

Cartilages

Types Histological Findings Specialized Cells Histological Appearance

Hyaline Cartilage

(Marble hard)

Location

Ends of long bone

Cartilagenous ring of

respiratory tract

Fetal skeleton

Function

Smooth surface for joint

movement

Flexibility

Support

Outer layer

o Perichondrium which is Dense

Irregular CT

Inner layer

o Chondrogenic area (not visible)

Spindled shape cells of

Chondroblasts

o Young cartilage

Single oval Chondrocyte in

lacunae

o Mature Cartilage

Lacunae

Isogenous group of cells (5-6

cells)

Highly basophilic territorial matrix

(due to GAG)

Interterritorial matrix

Fibers are INVINSIBLE due to high

concentration of GAG

Chondroblasts

Chondrocytes

Elastic Cartilage

(Rubber-like)

Location

Epiglotis

Nose

Ear auricle

Eustachian tube

Function

Supports

Maintain shape

Inner layer

o Chondrogenic area (not visible)

Spindled shape cells of

Chondroblasts

o Young cartilage

Single oval Chondrocyte in

lacunae

o Mature Cartilage

Lacunae

Isogenous group of cells (1-2

cells)

Less basophilic territorial matrix

(due to GAG)

Interterritorial matrix

o Elastin fibers are clearly VISIBLE due to

lesser concentration of GAG

Fibrocartilage

(In Between)

Location

Pubic symphasis

Intervertebral disk

Function

Support

Fusion

Lacunae

o Isogenous group of cells

(3-4 cells)

Fairly visible collagenous

and elastic fibers

Skin layer

Subcutaneous layer

Elastic Cartilage


Types Histological Findings Specialized

Cells

Histological Appearance

Bone Location

Compact bone

Spongy bone

Function

Support

Protection

Storage (marrow)

Movement

Lamellae

o Outer circumferential (not

seen)

Below Periosteum

o Inner circumferential (not

seen)

Before Endosteum

o Interstitial

In between the Osteon

Osteons

o Haversian canal in the middle

o Volksman’s canal runs

longitudinally (connecting the

Haversian canal)

o Lacunae and canaliculi for

Osteocytes

o Cementing line between the

lacunae

Osteoblast

Osteoclast


Blood

Types Histological Findings Histological Appearance Red Cells

Function

Gas carrying through

Heamoglobin

Haemoglobin (Hb)

Fetal Hb

o HbF (100%)

2 alpha

2 gamma

Adult

o HbA 1 (96%)

2 alpha

2 beta

o HbA 2 (2%)

2 alpha

2 delta

o HbF (2%)

2 alpha

2 gamma

Anucleated (NO NUCLEUS) and NO organelles, to give

more space for Haemoglobin (therefore considered to

be Post-cellular structure)

Pallor in the center, indicating biconcave in shape

Formation

Induced by Erythropoietin (EPO) from Peritubular

capillary of the Kidneys

Pluripotent Hemopoeitic Stem Cell –> CFU-S –> BFU-E –>

CFU-E –> Basophilic Erythroblast –> Polychromatophilic

Erythroblast –> Orthochromatophilic/Eosinophilic

Erythroblast –> ejection of nucleus –> Reticulocyte –>

Erythrocyte

Platelets Function

Heamostasis

Smooth disk in shape

Anucleated (NO NUCLEUS), therefore considered to be

post-cellular structure

Contains several organelles

Formation

Induced by Thrombopoietin from Liver

Pluripotent Heamopoeitic Stem Cell –> CFU-S –>CFU-

Meg–> Megakaryoblast –> Promegakaryocyte –>

Metamegakaryocyte –> Megakaryocyte –> Platelets

Megakaryocytes (in the Red Marrow)

Huge polyploidy cell

Multinucelated with dispersed chromatin

Numerous basophilic granules

Numerous cytoplasmic blebs


Granulocytes

Types Histological Findings Histological Appearance

Neutrophils

Function PMN, phagocytic

cells

Light pink cytoplasm

Lack of specific granules

Multilobulated nuclei, 2-3 lobes

Dark blue nucleus

The most abundant in leukocytes in the blood

Formation

Induced by Colony Stimulating Factor release by marrow cells

Pluripotent Heamopoeitic Stem Cell –> CFU-S –> CFU-GM –> CFU-G

–> Myeloblast –> Promyelocyte –> Neutromyelocyte –> Stab cells –

> Neutrophils

Basophils

Function Stimulates

hypersensitivity

Large amount of granules, they even compressed against its cell

membrane giving its angular appearance

The granules are stained by hematoxylin (BLUE) – acidic in nature

Basophil is the rarest leukocytes found in a normal blood smear

Formation

Induced by Colony Stimulating Factor released by marrow cells

Pluripotent Heamopoeitic Stem Cell –> CFU-S –> CFS-basophil –>

Myeloblast –> Promyelocyte –> Basophil myelocyte –> Basophil

metamyelocyte –> Stab cell –> Basophil

Eosinophils

Function

Stops

hypersensitivity Helminthic

infection

Contained numerous pinkish or reddish-orange granules

Azurophilic granules also present

Bilobed nucleus, makes it looks like a sausage with nuclear

projection linking the two lobes

Eosinophil is one of rarest leukocytes found in the normal blood

smear

Formation Induced by Colony Stimulating Factor released by marrow cells

Pluripotent Heamopoeitic Stem Cell –> CFU-S –> CFU-Eosinophil –>

Myeloblast –> Promyelocyte –> Eosinophil myelocyte –> Eosinophil

metamyelocyte –> Stab cell –> Eosinophil

Neutrophil


Agranulocytes

Types Histological Findings Histological Appearance

Lymphocytes Function

T cell

o T helper Cell (CD4+)

Induce the

formation of

Antibody and

memory cells by B

cell

o T cytotoxic Cell (CD 8+)

Killed tumor and

viral-infected cells

B cell

o Produce Antibody and

memory cells o Once entered the

tissue will be called as

Plasma cells

Contained a very huge nucleus located at the

center of the cell

Due to the huge size of nucleus, the cytoplasm is

somehow pushed to the periphery giving its

distinctive shape of a blue rim

The nucleus has a dense heterochromatin

Formation

Produce in red marrow, mature in Thymus

Pluripotent Heamapoeitic Stem Cell –> CFU-

Lymphocyte –> CFU-Lymphocyte T/Lymphocyte B

–> T/B lymphocyte –> T/B lymphoblast –> T/B

Lymphocyte

Monocytes

Function

Will form the

Mononuclear

Phagocyte System

The largest blood cell in the circulating

bloodstream

Nucleus is accentric, kidney shaped, and having

coarse chromatin network

Formation

Produce and mature in red marrow

Pluripotent Heamopoeitic Stem Cell –> CFU-S –>

CFU-GM –> CFU-Monocyte –> Promonocyte –>

Monocyte

Once enter the tissue it will form MACROPHAGE

histology of connective tissues

Documents