Practical 1: Morphology Flashcards
What are the two types of epithelia
Covering epithelia and glandular epithelia
How do we distinguish epithelia types
(3)
By their expression of cytokeratins
Pan cytokeratin antibodies will show all epithelia
Specific cytokines are expressed in specific cell types
How are epithelial cells specialised for their function?
(3)
Structural modification of their surface
Special types of junctional complexes
Internal modifications (associated with manufacture or secretion)
What two statements can be said about all epithelial cells?
All cells rest upon a basement membrane
All epithelia are a-vascular
What is the basis behind the classification of covering epithelia
Covering epithelia are classified based on:
The number of layers
The shape of the surface cells
What are the two classifications of covering epithelia based on their number of layers
Single layer = simple epithelium
Multiple layers = stratified epithelium
How is covering epithelium classified based on surface cells?
(3)
Flat plate like = squamous
Height = width = cuboidal
Height > width = columnar
Describe simple epithelia
Epithelia that are one cell thick
Describe pseudo-stratified epithelia
Epithelia that appear to be more than one cell thick but all the cells rest on the basement membrane
Describe stratified epithelia
These are many cells thick
Describe squamous epithelia
Epithelia made up of flattened cells shaped like paving stones or ‘fried eggs’
Describe cuboidal epithelia
Epithelia made up of isodiametric cells
Describe columnar epithelia
Epithelia made up of cells that are taller than they are wide
Describe transitional epithelia
Made up of cells that change their shape when the epithelium is stretched
What is glandular epithelium?
(3)
Cells specialised in producing a fluid secretion that differs in composition from blood or intercellular fluid
The chemical nature of this secretion may be protein, lipid or a complex of carbohydrate and protein
Some glands such as the mammary gland secrete all three substances
How do gland cells function
(2)
Gland cells produce and expel secretions to an extra-cellular compartment
These secretions are products that are not used by the cell itself but are of importance to the organism
What type of epithelium are glands derived from and how does this process occur
(3)
Glands are always derived from covering epithelia
Derived by means of cell proliferation and invasion of sub-adjacent connective tissue
This is then followed by further differentiation to form the actual gland
What are the different classifications of glandular epithelium
Single cell glands
Multicellular glands
What are single cell glands
Glands associated with surface epithelium
Give an example of a single cell gland
Goblet cell
What are multicellular glands?
(3)
Glands made of more than 1 secretory cells
Embedded within underlying connective tissue
Divided into two types: exocrine and endocrine
What is the difference between exocrine and endocrine glands?
Endocrine have ducts
Exocrine are ductless
What are the two cell populations seen in connective tissue?
Resident cell populations
Transient cell populations
What cells make up the resident cell population of connective tissue?
Fibroblasts and fribrocytes
Macrophages
Mast cells
Chromatophores (pigment)
Adipocytes
What four cells make up the transient cell population of connective tissue?
Plasma cells
Eosinophils
Neutrophils
Lymphocytes
Comment on fibroblasts and fibrocytes as a cell population
Most important and most common connective tissue cell
What do fibroblasts do?
They actively produce the extracellular matrix (ECM), fibres and groundsubstance
How do you identify fibroblasts
They have prominent nucleoli and a basophilic cytoplasm
How do you identify fibrocytes
They are involved in the maintenance of the extra cellular matrix
They can differentiate into other types of CT cell
List the three types of connective tissue fibres produced by fibroblasts
Collagen fibres
Reticular fibres
Elastic fibres
Write a note on collagen fibres
(3)
15 different types
High tensile strength/low elasticity
Fibres arranged in bundles
What do reticular fibres do?
They provide a delicate framework in lymph nodes, liver and spleen and around blood vessels and nerves
What do elastic fibres do?
Provide strength and can stretch and recoil
What are the four types of connective tissue
Loose (areolar) CT
Dense (irregular and regular) CT - common
Reticular CT
Adipose CT
How is connective tissue categorised
Based on variation in quantity and arrangement of fibres associated with the extracellular matrix
Where is muscle found in the body
(3)
Walls of hallow organs
Muscles associated with the skeleton
Heart
What are the three types of muscle fibres
Smooth
Skeletal (striated)
Cardiac (striated)
What are the two types of muscle
Voluntary
Involuntary
List the six functions of the liver
Regulation of blood glucose levels
Regulation of blood lipid levels
Synthesis of plasma proteins
Detoxification
Excretion (blood filtering)
Exocrine secretion
What type of connective tissue is found in the liver
Reticular fibres
What are the three regions of the respiratory system?
Conducting airways
Transitional region
Gas exchange surfaces
What structures make up the conducting airway of the lung
(8)
Nose
Nasal cavity
Nasopharynx
Larynx
Trachea
Two primary bronchi
Lobar Bronchi
Bronchioles
What structure makes up the transitional region of the lung
Respiratory bronchioles
What three regions make up the gas exchange surfaces
Alveolar ducts
Alveolar sacs
Alveoli
What is the role of mucous in the respiratory system
(4)
Goblet cells and sub-mucosal glands form the mucus sheet
Particulate matter becomes trapped in this sheet
Mucous is wafter towards pharynx via mucocillary escalator
Serous glands moisten inhaled air
What does BALT stand for
Bronchial associated lymphoid tissue in lamina propria
Describe the structure of the bronchioles
(6)
No cartilage
Smooth muscle
Pseudo stratified ciliated columnar
No seromucous glands
Goblet cells starting to disappear
Clara (Club) cells appear
What are alvoeli
Sac like pockets lined by simple squamous epithelium
Type 1 pneumocytes
Type 2 pneumocyte
What is a type 1 pneumocyte
Squamous alveolar cell
97% of alveoli
What is a type 2 pneumocyte
Septal cells
3% of alveoli
Produce surfactant
Reduce surface tension
What are the four layers of the GI tract
Mucosa
Submucosa
Muscularis Externa
Serosa/adventitia
What is the mucosa
Epithelium
What is the submucosa
Connective tissue + blood vessels + glands
What is the muscularis externa of the GIT
Inner circular muscle
Outer longitudinal muscle
What is the serosa/adventita
A serous membrane inside the body cavity
A loose layer of CT outside the body cavity
