HUMAN TISSUES by: pr ,Dr, Sanaa El-Sherbiny

Cells are :The unit of structure of

living creatures

In 1665 Robert Hooke, observed thin

sections of cork with a simple

microscope of his own

making. He described his

findings as having

the appearance

of cells in a jail.

Cells and Tissues

• Cytology or cell biology : the study of cells

• Histology : the micro-study of living tissues

and organs of all living creatures .

• Levels of Organization of human:

cell---tissue --organ---systems--body

• Types of organisms:

• Unicellular Organism:

-consists of one cell (bacteria , amiba)

• Multicellular Organism:

-consists of more than one cell ( plants and animals)

Human cell formed of 3 Main Parts

1) Nucleus – a spherical body often located near the center of the cell which contains the chromosomes that carry the genetic code of the cell and serves as the cell’s master control center.

2) Cytoplasm – the fluid medium for the many molecules and organelles the cell contains

3) Cell organelles: Membranous and

non-membranous cell organelles .

Tissue : definition

•Types of tissues

A group of connected, interdependent cells

that cooperate to perform

a specific function

1. Epithelial Tissue

2. Connective Tissue

3. Muscle Tissue

4. Nervous Tissue

Epithelial Tissues • General Features

1- Formed of one or more Cellular Layer

on a Basement Membrane.

2- Not Penetrated By Blood Vessels ,

get Blood supply from underlying connective tissue.

3- but nerve fibers ramify between cells.

4- Rapid Rate of Cell Regeneration.

5- Embriologically derived from

ectoderm, mesoderm or endoderm.

** Structural Classification According to number of layers and

Cell Shapes: 2 types :

simple and stratified.

**Functional Classification: 1-covering-epith.

2-glandular-epith.

3-neuro-epith.

Classifications of Epithelia

• Simple • stratified

Simple epithelium • One layer of cells on a

basement membrane

SIMPLE Squamous . epithelium

**structure: one layer of flat cells

on a basement membrane

**Sites : – THE Lung ALVEOLI

– ENDOTHELIUM

LINING blood and

LYMPHATIC

VESSELS

WHICH 1

IS

YOURS…

1 or 2…?

1

2

simple cuboidal

epithelium

** formed of one layer of cubical cells on a basement membrane

– Sites: lining the secretory

follicles in salivary and

– Thyroid glands.

– Lining medium sized ducts of glands

– Lining kidney tubules .

Simple Columnar Epithelium one layer of columnar cells on a basemen

membrane

Figure 4.3c

simple columnar epithelium (types)

1-Non modified :lining ducts of glands

• 2-Modified:- absorptive Epithelium, lining

the , small intestine

- secretory Epithelium, lining the stomach.

- ciliated, Epithelium, lining the

uterus and fallopian tube

Microvilli

Pseudo-stratified Columnar

Epithelium

• One layer of overcrowded cells with

many levels of nuclei , so is one type

• Of simple epithelium

Pseudostratified Ciliated Columnar Epithelium lining trachea and bronchi

Figure 4.3d

20

بسم هللا الرحمن الرحيم

)رأمنمممار مممما خرر أممما خ ران ممم أولمممير ر ممذااروخمخر رممممنرخطفم يخخ

رل مممارممم م ررمخبمم نخخر وضمموأمممخر ممماخر ممممارممممنرخ مممخرر

رر العظامرووخررم يخخر مخمنة رر شأوآرأونرم خ هارالنذىرأ

رع يخر ر ق )ووخخربكخر

عظيم له ال

(79: 77 سورة يس) صدق ال

Stratified Epithelium

Stratified Squamous Keratinized

Epithelium ( st,sq,ker,epith)

Function: Protection

Locations:

epidermis

of

the skin

Stratified Squamous

Epithelium

• Many layers

• Basal one columnar

• Intermediate layers

• Polygonal in shape

• Upper layers are

• Squamous flat cells with

central oval nuclei

Stratified Squamous non-keratinized Epithelium

:found in* mouth cavity

*conjunctiva of the eye

Figure 4.3e

Transitional Epithelium

Figure 4.3h

TRANSITIONAL EPITH.

• many cell layers -

stretch

• cube-shaped and

elongated cells

• line urinary

bladder, ureters,

and part of urethra

Transitional Epithelium

• 6-8 layers in empty

bladder

• 2-3 layers in full one

• Basal layer columnar

on ill defined b.m

• Intermediate layers

polygonal

• Upper layer large

may be bi-nucleated

• Second layer flask

shaped

GLANDULAR EPITHELIUM

• THE CELLS ARE SPECIALISED FOR SECRETION.

• ACCORDING TO NUMBER OF SECRETORY CELLS WE HAVE:

• UNICELLULAR GLANDS AS GOBLET CELLS.

• MULTICELLULAR GLANDS AS SALIVARYGLANDS.

• Uni-cellular glands as

GOBLET CELLS.

• Multi-cellular

gland

1-ACCORDING TO

SECRETORY PASSAGES

• A-EXOCRIN GLANDS:

• Have duct system

• SUCH AS :salivary glands.

• -ENDOCRINE GLANDS:

• No ducts ,secrete directly into the blood

• SUCH AS:THE PITUITARY GLAND.

Types

Major ♥ Submandibular

♥ Sublingual

♥ Parotid

Minor ♥ Buccal

♥ Labial

♥ Palatine

♥ Lingual

Second Year Section 4 2009/2010

Function Secretion of

saliva

Second Year Section 4 2009/2010

Structure

Second Year Section 4 2009/2010

• Connective tissue element Stroma

• Epithelial element Parenchyma

stroma

1- Capsule

2- Trabeculae

3- Reticular network

Parenchyma 1.Secretory part (salivary acini)

2.Transport system (branching

ducts)

Model of the gland: a bunch of grapes: berry= acinus

stalk of berry: intercalated duct

Classification

According to the nature of

secretion

There are 3 types:

Mucous

Serous

Mucoserous

Second Year Section 4 2009/2010

Second Year Section 4 2009/2010

4-ACCORDING TO SHAPE OF

SECRETORY PART

• ALVEOLAR GLANDS:

• AS MAMMARY GLANDS.

• Tubular GLANDS

• AS GASTRIC GLANDS

• TUBULO-ALVEOLAR

GLANDS AS

SALIVARY GLANDS

NEURO EPITHELIUM • THE EPITHELIAL CELLS ARE SPECIALIZED FOR

RECEPTION OF

• EXTERNAL STIMULI SUCH AS:

• RETINA OF THE EYE, OLFACTORY MUCOSA,

TASE BUDS and ORGAN OF CORTI .

• Neuroepithelium is formed of :

• Sensory cells &

• Supporting cells

• And stem basal

• cells

Taste buds

Olfactory epithelium and all neuro-

epithelium are formed of3 types of cells :

1-sensory cells 2-supporting cells

and 3-basal stem cells

Name this type of epithelium-------

Mention two sites for simple Squamous

Epithelium 1----------

2-------------

Figure 4.3a

This is --- ---- epithelium

Name this type of epithelium-------

Stratified

epithelium

This is ----- ----- ------

epithelium

it is found in -----------------------

This epithelium is --- ----- --------

-------- ------- with ------------ cells.

This is ------ ----- ----------------

its site is -----------------------

The arrow indicates ----- -------

This is ------ ----- -------------epithelium

its site is -----------------------------------

• Identify a tissue type

• 1. mucous gland

• 2. stratified columnar epithelium

• 3. stratified squamous epithelium

• 4. unicellular exocrine gland (goblet cell)

• Identify a tissue type

• 1. alveolar gland

• 2. mucous gland

• 3. simple columnar

epithelium

• 4. simple cuboidal

epithelium

• Identify a tissue type

• 1. mucous gland

• 2. serous gland

• 3. stratified columnar epithelium

• 4. pseudostratified

• 5. transitional epithelium

• Identify a tissue type

• 1. stratified cuboidal epithelium

• 2. stratified columnar epithelium

• 3. simple columnar epithelium

• 4. mucous acinus

• 5- simple columnar epithelium with goblet cells(absorptive )

• This is a histological section of:

• 1- Stratified squamous epithelium.

• 2- simple squamous epithelium.

• 3- simple cuboidal epithelium.

• 4- simple columnar epithelium.

• 5- stratified columnar epithelium.