basic histology - graftonps.org

Basic Histology By Mrs. Bailey

Primary Tissues 1. Epithelial Tissue

2. Connective Tissue

3. Muscle Tissue

4. Nervous Tissue

• Very cellular

• Supported by underlying connective tissue

• Epithelial & connective tissue are separated by a basement

membrane, which is produced by both tissues.

• Packed together tightly & orderly.

Tight junctions may occur between cells.

• Avascular. Receives its nutrients

by diffusion from the underlying

connective tissue.

• Two types:

a. Covering/Lining

b. Glandular

Epithelium

• Faces a space such as the lumen

of a blood vessel or intestine.

Apical surface = adjacent

to lumen

Basal surface = adjacent

to basement membrane

• Mucous membranes - line organs and cavities

- secretion of mucous from glands

Serous membranes - cover and protect organs

Hint: These surfaces are “places”, not “things”.

Covering/Lining Epithelium

a. Exocrine b. Endocrine secretions enter ducts secretions enter bloodstream

Glandular Epithelium

Epithelial Tissue Types

Layers : Simple - single layer – provides a selective

barrier allowing diffusion, filtration, secretion,

and absorption.

Stratified - several layers –

subject to wear and tear –

forms a protective barrier.

Pseudostratified –

appears to be several layers,

but is actually only a single layer.

Shapes

• Squamous - flattened

• Cuboidal - cube

• Columnar - cylindrical

• Transitional – change shape

They are rounder when the tissue

is relaxed and flatter when the

tissue is stretched.

NOTE: When viewed from

the apical surface, all epithelial

cells have a similar shape.

Types of Epithelial Tissue

Simple SQUAMOUS Epithelium

Epithelial lining of an blood vessel.


Epithelial lining of an alveolus.

Refer

to

page

127


Epithelial lining of an alveolus.


(1) Outer layer of Bowman's capsule (yellow arrows)

(2) Inner layer of Bowman's capsule (red arrows)

(3) Capillary endothelial cells (purple arrows)


Our

microscope

slide

Simple CUBOIDAL Epithelium

Ovary Surface Refer

to

page

128


Collecting tubules of Kidney


What would this area be called?


Our

microscope

slide

Simple COLUMNAR Epithelium

Refer

to

page

129


Microvilli


Gall bladder

Goblet cell

Intestine - Villus


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slide

Name those parts!


5

Stratified Squamous Epithelium

Cheek cells


NON-keratinized

Refer

to

page

130


Keratinized Waterproof!


NON-keratinized

Our

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Transitional Epithelium

Refer

to

page

131

Urinary

Bladder


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Pseudostratified Ciliated Columnar Epithelium

All of the cells are in contact with the basement membrane, but not all

of them reach the surface. The cells that do reach the surface are either

ciliated or goblet cells (mucus-secreting cells). Refer to

page 131

Respiratory Tract


1

2

3

4


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• Most abundant tissue in the body.

• Supports epithelial tissue and connects it to other tissues.

Provides coverings that support and protect muscle and

nervous tissue.

• Most are not very cellular, usually containing more

matrix than cells.

• Most are vascular and regenerate easily.

Cells: Fibroblasts, Macrophage, Plasma cells,

Mast cells, Adipocytes, WBC's

Connective Tissue

EXCEPTIONS: Tendons – poorly vascularized; do NOT heal easily

Cartilage – avascular - does NOT heal easily

Connective Tissue Matrix Ground substance + Fibers

(Composition is used in classifying connective tissue)

Ground Substance = polysaccharides + proteins

Fibers:

• Collagen - most abundant protein in body

• Elastic fibers - stretchable (in skin, BV, lungs)

• Reticular fibers - support and strength

• Loose

• Dense

• Cartilage

• Bone

• Blood

Types of Connective Tissue

Loose Connective Tissue • Fibers are loosely arranged.

• Collagen, elastic, and reticular fibers provide strength,

elasticity, and support.

• Fibroblasts and adipocytes permanently reside here.

• Subcutaneous layer of skin.

Areolar

Reticular

Adipose

Areolar Connective Tissue

Fibroblast

nucleus

Mast cell

Elastic

fiber

Collagen

fiber

Ground

substance

Refer to page 136

Areolar Connective Tissue

Our

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Reticular Connective Tissue

Reticular

fiber

Ground

substance

Refer to page 138

Nucleus of

Reticulocyte

Now you try …………….

Reticular Connective Tissue

Our

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slide

Adipose Tissue

Refer to page 137

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Adipose Tissue

Dense Connective Tissue • Matrix is packed with fibers and contains very little ground

substance and few fibroblasts.

• Tendons, Ligaments, Skin dermis, Artery wall

Dense Regular

Dense Irregular

Dense Regular Elastic

Dense Regular Connective Tissue Tendon

Refer

to

page 139

Dense Regular Connective Tissue

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Dense Irregular Connective Tissue Skin Dermis

Refer

to

page 139

Dense Regular Elastic

Connective Tissue

Wall of Artery; Ligament

Elastic fiber

Collagen

bundles

Fibroblast

nucleus

Now you try ……………. HINT: This is an ARTERY, which contains dense regular elastic CT.

• Peach outlines?

• Blue arrows?

• Green arrow?

• Grey block arrow?

• Yellow block arrow?

Cartilage Contains cells called chondrocytes housed in spaces called

"lacunae". Some lacunae contain more than one chondrocyte ...

these are daughter cells formed after division.

Hyaline - ends of bone; support rings of respiratory tubes

Elastic – elastin fibers; epiglottis; nose

Fibrocartilage - much collagen; intervertebral discs

Refer to page 140

Hyaline Cartilage

1.

2.

3.


Hyaline Cartilage

Our

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Refer to page 141

Elastic Cartilage

Elastic Cartilage

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Refer to page 141

Fibrocartilage

Fibrocartilage

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Bone • Dense - middle portion (osteon); Spongy – ends (trabeculae)

• Bone tissue is unlike other

connective tissues in that

the extracellular matrix

becomes calcified.

• Lamellae – layers of matrix;

concentric = within osteons;

interstitial = in between osteons.

• Contains cells called

osteocytes housed in

lacunae.

• Haversian Canal - extends the length of each osteon

through its center; contains blood vessels, lymphatic

vessels, and nerves.

• Volkmann’s Canals – connect Haversian canals to each

other; communication; contain nerves and vessels that

carry blood and lymph from the exterior bone surface to

the osteons.

• Canaliculi – tiny canals radiating

in all directions from the lacunae

and connecting them to each other

as well as to the Haversian canal.

Bone

Bone Osteon

Volkmann’s

canals

Concentric

lamellae

Interstitial

lamellae

Haversian

canal

Lacunae

Refer to page 140

Canaliculi

1.

2.

3.

4.

What do you refer

to each of the

“larger circles”?


Bone

Our

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slide

Blood

Refer to page 142

Platelets

White

blood cells

(Leukocytes)

Red

blood cells

(Erythrocytes)

Plasma

matrix

Blood

Our

microscope

slide

Muscle Tissue • Contains muscle cells and connective tissue. Thin layers of

connective tissue surround muscle cells to protect and support

them.

• Very cellular. Muscle cells = muscle fibers.

Fibers contain many microfilaments (myofilaments) - cause

muscle cells to shorten (contract) when stimulated.

Skeletal (striated; voluntary; multinucleated cells)

Cardiac (striated; involuntary; multinucleated cells;

branching cells; intercalated disks)

Smooth (non-striated; involuntary; uninucleated cells;

tapered cells)

Muscle Tissue - Skeletal

Refer to page 144

Our

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Muscle Tissue - Skeletal

Muscle Tissue - Smooth

Refer to page 144

Similar to

our

microscope

slide

Muscle Tissue - Smooth

Muscle Tissue - Cardiac

Refer to page 145

Our

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Muscle Tissue - Cardiac

Nervous Tissue • Forms the brain, spinal cord, and nerves.

• Two basic categories of nervous tissue cells:

a. Neurons – receive and send information; amitotic

REVIEW: axon, dendrite, cell body

b. Neuroglial cells – support the neurons; divide and

replace themselves

• Highly vascularized

Refer to page 146

Glial cells

Nervous Tissue

Our

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slide

1. 2.

3.

1&2


3

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