Transcript Histology Of Respiratory System

THE RESPIRATORY SYSTEM
• The complex of organs and tissue which are
necessary to exchange blood carbon dioxide
(CO2) with air oxygen (O2) is called the
respiratory system. It consists of
• structures, which function as ducts, and which
together are called the Conductive Portion of
the respiratory system
• structures which form the Respiratory Portion
of the respiratory system, in which the exchange
of CO2 and O2 is occurring and
Nasal Cavity
• The Nasal cavity is divided into three structurally
and functionally different parts.
• The Vestibules (the first ~1.5 cm of the conductive
portion following the nostrils) are lined with a
keratinised stratified squamous epithelium.
Hairs, which filter large particulate matter out of the
airstream, and sebaceous glands are also present.
•
At the transition from the vestibule to the
respiratory region of the nasal cavity the epithelium
becomes first stratified squamous and
then pseudostratified columnar and ciliated.
Mucus producing goblet cells are present in the
epithelium.
The olfactory epithelium
• Formed by Olfactory Cells, Sustentacular Cells
and basal cells. Basal cells can be identified by their
location. Sustentacular cells are preferentially
located in the superficial cell.
• Cilia are not visible and goblet cells are absent
from the olfactory epithelium. Cilia do not move,
because they Lack Dynein Arms which are
necessary for cilial motility. The cell membrane
covering the surface of the cilia contains olfactory
receptors which Lightly stained rounded areas in
the lamina propria represent bundles of Olfactory
Axons in the lamina propria. Small mucous glands,
Olfactory Glands Or Bowman's Glands,
Nasal Cavity, Olfactory Region, rat - Alcian blue &
van Gieson
Respiratory region of the nasal cavity - H&E, van
Gieson
Nasal Cavity
• The surface of the lateral parts of the nasal
cavity is thrown into folds by bony projections
called Conchae. These folds increase the
surface area of the nasal cavity and create
turbulence in the stream of passing air, both of
which facilitate the conditioning (warming,
cooling and filtration) of the air. Mucous and
serous glands in the connective tissue
underlying the epithelium, the lamina propria,
supplement the secretion of the goblet cells.
Superficial Blood Vessels
Pharynx
• The pharynx connects the nasal cavity with the
larynx.
• The pharynx is either lined with respiratory
epithelium (nasopharynx) or with a stratified
squamous epithelium (oropharynx), which
also covers the surfaces of the oral cavity and
the oesophagus. Lymphocytes frequently
accumulate beneath the epithelium of the
pharynx.
• Accumulations of lymphoid tissues surrounding
the openings of the digestive and respiratory
passages form the Tonsils.
Pseudostratified Columnar Epithelium
• Composed of one Layer of Cells
• All cells of this type of epithelium are in contact with the
basement membrane, but not all of them reach the
surface of the epithelium.
• Nuclei of the epithelial cells are typically located in the
widest part of the cell. Consequently, the nuclei of cells
which do or do not reach the surface of the epithelium
are often located at different heights within the
epithelium and give the epithelium a stratified
appearance.
• The epithelium will look stratified but it is not - hence its
name "pseudostratified".
• Pseudostratified columnar epithelia are found in the
Respiratory System
Pseudostratified columnar epithelium
Larynx
• The vocal folds of the larynx control airflow and
allow the production of sound. The vocal folds
are lined by stratified squamous epithelium
and contain the muscle (striated, skeletal) and
ligaments needed to control the tension of the
vocal folds. The larynx is supported by a set of
U/C shaped cartilages.
• The number of goblet cells is variable and
depends on physical or chemical irritation of
the epithelium which increase goblet cell
number. Prolonged intense irritation of the
epithelium may lead to its transformation to a
stratified squamous epithelium (squamous
metaplasia).
Cartilage Platelets
Tertiary Bronchiole
Alveolar Cells
•
•
Alveolar type I cells (small alveolar cells or type I
pneumocytes) are extremely flattened (the cell may be
as thin as 0.05 µm) and form the bulk (95%) of the
surface of the alveolar walls.
Alveolar type II cells (large alveolar cells or type II
pneumocytes) are irregularly (sometimes cuboidal)
shaped. They form small bulges on the alveolar walls.
Type II alveolar cells contain large number of granules
called cytosomes (or multilamellar bodies), which
consist of Precursors To Pulmonary Surfactant (the
mixture of phospholipids which keep surface tension
in the alveoli low) . There are less type II cells than
type I cells. But since Type I are smaller in size we
see more type I in one focus of the section.
4
1
2
3
5
6
Organ? 40X
1
2
3
4
Organ? 400X
Tissue from Trachea slides 2-3
Slide # 2: Trachea (40X)
1. Lumen of the trachea
2. Epithelium of the Trachea
3. Submucosa
4. Seromucous Gland
5. Hyaline Cartilage
6. Adventitia
Slide # 3: Trachea (400X)
1. Lumen
2. Pseudostratified Ciliated Columnar Epithelium (Cilia not
seen)
3. Lamina Propria
4. Submucosa
7
3
1
5
2
8
4
6
Organ? 40X
2
8
6
1
5
7
4
3
Organ? 100X
2
5
3
1
6
7
4
Organ? 400X
Tissue from Tertiary Bronchi slides 57
Slide # 5: Tertiary Bronchi with Lung tissue (40X)
1. Lumen
2. Epithelium of the Tertiary Bronchi
3. Lamina Propria
4. Seromucous Gland
5. Hyaline Cartilage
6. Smooth Muscle
7. Blood Vessel
8. Lung Tissue
Tissue from Tertiary Bronchi slides 57
Slide # 6: Tertiary Bronchi with Lung tissue (40X)
1. Lumen
2. Epithelium of the Tertiary Bronchi
3. Lamina Propria
4. Seromucous Gland
5. Hyaline Cartilage
6. Smooth Muscle
7. Submucosa
8. Lung Tissue
Tissue from Tertiary Bronchi slides 57
Slide # 7: Tertiary Bronchi with Lung tissue (400X)
1. Lumen
2. Pseudostratified Ciliated Columnar Epithelium
3. Lamina Propria
4. Seromucous Gland
5. Hyaline Cartilage
6. Smooth Muscle
7. Submucosa
2
3
1
5
4
Organ? 40X
2
5
3
1
4
Organ? 100X
3
2
1
Organ? 400X
Tissue from Lung slides 11-13
Slide # 11: Lung (40X)
1. Visceral pleura
2. Respiratory bronchiole
3. Alveolar duct
4. Alveolar sac
5. Alveolus
Slide # 12: Trachea (100X)
1. Visceral pleura
2. Respiratory bronchiole
3. Alveolar duct
4. Alveolar sac
5. Alveolus
Tissue from Lung slides 11-13
Slide # 13: Lung (40X)
1. Alveolar sac
2. Alveolus
3. Blood Vessel
Cystic Fibrosis and the Lungs
Cystic Fibrosis
• One of the most common autosomalrecessive diseases.
• First seen in newborn babies as:
•
•
•
•
•
Persistant diarrhea
Frequent Pneumonia
Chronic coughing
Salty skin
Poor Growth
Cystic Fibrosis
– Autosomal recessive Genetic disorder
Mutation in CFTR (cystic fibrosis
transmembrane conductance regulator) gene
– Product of this gene makes chloride ion
channel
•
Inherited disease of secretory glands
(which make mucous and sweat)
Cystic Fibrosis
• Pathophysiology
– Mutation in the CFTR gene
– The protein created by this gene is anchored
to the outer membrane of cells in the sweat
glands, lungs, pancreas, and other affected
organs
– The protein spans this membrane and acts as
A Channel Connecting The Inner Part Of
The Cell (Cytoplasm) To The Surrounding
Fluid
Cystic Fibrosis
• Pathophysiology
– This channel is primarily responsible for
Controlling The Movement Of Chloride
From Inside To Outside Of The Cell;
however, in the sweat ducts it facilitates the
movement of chloride from the sweat into the
cytoplasm
– When the CFTR protein does not work,
Chloride Is Trapped Inside The Cells In The
Airway And Outside In The Skin
Cystic Fibrosis
• Mucus Becomes Thick And Sticky
• Mucus Builds Up In Lungs And Blocks
Airways
• Buildup Of Mucus Makes It Easy For
Bacteria To Grow
• This Leads To Repeated, Serious Lung
Infections. Over Time, These Infections
Can Severely Damage Lungs
Healthy and CF Lung
Cystic Fibrosis (GIT)
• The thick, sticky mucus also can Block
Tubes, or ducts in pancreas
• As a result, the digestive enzymes that
pancreas makes can't reach small intestine
• Intestines can't fully absorb fats and proteins
• This can cause vitamin deficiency and
malnutrition
• It also can cause bulky stools, intestinal gas,
a swollen belly from severe constipation, and
pain or discomfort
Cystic Fibrosis (SKIN)
• Also causes sweat to become very salty
• As a result body loses large amounts of
salt during sweating
• This can upset the balance of minerals in
blood
CF and the Lungs
• The lungs when affected by CF have very
thick mucous.
• Unlike other parts of the body that it is
unknown why the missing CFTR gene
effects the lungs so greatly.
• The mucous that builds up is able to hold
bacteria so large amounts of bacteria
begin to grow in the lungs.
Genetic information about CF
• The (CFTR) gene responsible for Cystic
Fibrosis (CFTR) was determined to be at
the location to be 7q31.2.
• The gene that is encoded is 1480 proteins
long with the mutation causing CF coming
at the 508th amino acid location with the
loss of phenylalanine
How the lungs work
• The lungs work after receiving air by:
– The air enters the nose or mouth where it is
filtered, warmed, and moistened.
– The air then travels down the throat and
enters the trachea.
– The air proceeds down the trachea, which
branches into the left and right bronchi.
– These two main stem bronchi continue to
branch into smaller bronchi and they
eventually branch into bronchioles.
How the lungs work continued
• After the air reaches the bronchioles:
– The bronchioles end in sacs known as alveoli.
They act as balloons that inflate when
breathing in.
– Gas exchange occurs at the alveoli. The
concentration of oxygen is greater in the
alveoli during inspiration then in the capillaries
so the oxygen will diffuse across the alveolar
walls and enter the blood plasma and carbon
dioxide undergoes the opposite process.
Definitions
• Emphysema - abnormal permanent enlargement of
the airspace distal to the terminal bronchioles,
accompanied by destruction of their walls and without
obvious fibrosis.
• Chronic Bronchitis - presence of chronic
productive cough for 3 months in each of 2 successive
years…
• COPD - disease state characterized by airflow
limitation that is not fully reversible.
DEFINITION
• COPD is characterised by airflow obstruction.
• air flow obstruction is usually progressive
• It is not fully reversible
• does not change markedly over several months
.
• The disease is pre-dominantly caused by smoking.
CAUSES OF COPD
SMOKING:
•90 % of cases,are caused by smoking
•15% are susceptible.
•Lung function decline is 3 times faster
•If smoking stops, at one year FEV1 decline is age related
(Morgan & Britton 2003)
ALPHA 1 ANTITRIPSIN DEFICIENCY:GENETIC
•Found in only 1% of cases.
OCCUPATIONAL EXPOSURE TO RESPIRATORY
POLLUTANTS:
Chemicals, dust, atmospheric pollutants, inherited tendency
CHRONIC BRONCHITIS
•
•
•
Continuous inflammation of the cells lining the
bronchi
Mucous hypersecretion
Destruction of the cilia, impairing mucous clearance
leading to increased risk of infection
Diagnosed by the production of sputum and cough on
most days for three months in two consecutive years
EMPHYSEMA
• Destructive of the alveoli and terminal bronchioles
• Loss of elasticity of smaller airways
• Loss of patency of bronchioles