Practical 1: Morphology

Question 1

What are the two types of epithelia

Answer 1

Covering epithelia and glandular epithelia

Question 2

How do we distinguish epithelia types
(3)

Answer 2

By their expression of cytokeratins

Pan cytokeratin antibodies will show all epithelia

Specific cytokines are expressed in specific cell types

Question 3

How are epithelial cells specialised for their function?
(3)

Answer 3

Structural modification of their surface

Special types of junctional complexes

Internal modifications (associated with manufacture or secretion)

Question 4

What two statements can be said about all epithelial cells?

Answer 4

All cells rest upon a basement membrane

All epithelia are a-vascular

Question 5

What is the basis behind the classification of covering epithelia

Answer 5

Covering epithelia are classified based on:

The number of layers

The shape of the surface cells

Question 6

What are the two classifications of covering epithelia based on their number of layers

Answer 6

Single layer = simple epithelium

Multiple layers = stratified epithelium

Question 7

How is covering epithelium classified based on surface cells?
(3)

Answer 7

Flat plate like = squamous

Height = width = cuboidal

Height > width = columnar

Question 8

Describe simple epithelia

Answer 8

Epithelia that are one cell thick

Question 9

Describe pseudo-stratified epithelia

Answer 9

Epithelia that appear to be more than one cell thick but all the cells rest on the basement membrane

Question 10

Describe stratified epithelia

Answer 10

These are many cells thick

Question 11

Describe squamous epithelia

Answer 11

Epithelia made up of flattened cells shaped like paving stones or ‘fried eggs’

Question 12

Describe cuboidal epithelia

Answer 12

Epithelia made up of isodiametric cells

Question 13

Describe columnar epithelia

Answer 13

Epithelia made up of cells that are taller than they are wide

Question 14

Describe transitional epithelia

Answer 14

Made up of cells that change their shape when the epithelium is stretched

Question 15

What is glandular epithelium?
(3)

Answer 15

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

Question 16

How do gland cells function
(2)

Answer 16

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

Question 17

What type of epithelium are glands derived from and how does this process occur
(3)

Answer 17

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

Question 18

What are the different classifications of glandular epithelium

Answer 18

Single cell glands

Multicellular glands

Question 19

What are single cell glands

Answer 19

Glands associated with surface epithelium

Question 20

Give an example of a single cell gland

Answer 20

Goblet cell

Question 21

What are multicellular glands?
(3)

Answer 21

Glands made of more than 1 secretory cells

Embedded within underlying connective tissue

Divided into two types: exocrine and endocrine

Question 22

What is the difference between exocrine and endocrine glands?

Answer 22

Endocrine have ducts

Exocrine are ductless

Question 23

What are the two cell populations seen in connective tissue?

Answer 23

Resident cell populations

Transient cell populations

Question 24

What cells make up the resident cell population of connective tissue?

Answer 24

Fibroblasts and fribrocytes

Macrophages

Mast cells

Chromatophores (pigment)

Adipocytes

Question 25

What four cells make up the transient cell population of connective tissue?

Answer 25

Plasma cells Eosinophils Neutrophils Lymphocytes

Question 26

Comment on fibroblasts and fibrocytes as a cell population

Answer 26

Most important and most common connective tissue cell

Question 27

What do fibroblasts do?

Answer 27

They actively produce the extracellular matrix (ECM), fibres and groundsubstance

Question 28

How do you identify fibroblasts

Answer 28

They have prominent nucleoli and a basophilic cytoplasm

Question 29

How do you identify fibrocytes

Answer 29

They are involved in the maintenance of the extra cellular matrix They can differentiate into other types of CT cell

Question 30

List the three types of connective tissue fibres produced by fibroblasts

Answer 30

Collagen fibres Reticular fibres Elastic fibres

Question 31

Write a note on collagen fibres (3)

Answer 31

15 different types High tensile strength/low elasticity Fibres arranged in bundles

Question 32

What do reticular fibres do?

Answer 32

They provide a delicate framework in lymph nodes, liver and spleen and around blood vessels and nerves

Question 33

What do elastic fibres do?

Answer 33

Provide strength and can stretch and recoil

Question 34

What are the four types of connective tissue

Answer 34

Loose (areolar) CT Dense (irregular and regular) CT - common Reticular CT Adipose CT

Question 35

How is connective tissue categorised

Answer 35

Based on variation in quantity and arrangement of fibres associated with the extracellular matrix

Question 36

Where is muscle found in the body (3)

Answer 36

Walls of hallow organs Muscles associated with the skeleton Heart

Question 37

What are the three types of muscle fibres

Answer 37

Smooth Skeletal (striated) Cardiac (striated)

Question 38

What are the two types of muscle

Answer 38

Voluntary Involuntary

Question 39

List the six functions of the liver

Answer 39

Regulation of blood glucose levels Regulation of blood lipid levels Synthesis of plasma proteins Detoxification Excretion (blood filtering) Exocrine secretion

Question 40

What type of connective tissue is found in the liver

Answer 40

Reticular fibres

Question 41

What are the three regions of the respiratory system?

Answer 41

Conducting airways Transitional region Gas exchange surfaces

Question 42

What structures make up the conducting airway of the lung (8)

Answer 42

Nose Nasal cavity Nasopharynx Larynx Trachea Two primary bronchi Lobar Bronchi Bronchioles

Question 43

What structure makes up the transitional region of the lung

Answer 43

Respiratory bronchioles

Question 44

What three regions make up the gas exchange surfaces

Answer 44

Alveolar ducts Alveolar sacs Alveoli

Question 45

What is the role of mucous in the respiratory system (4)

Answer 45

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

Question 46

What does BALT stand for

Answer 46

Bronchial associated lymphoid tissue in lamina propria

Question 47

Describe the structure of the bronchioles (6)

Answer 47

No cartilage Smooth muscle Pseudo stratified ciliated columnar No seromucous glands Goblet cells starting to disappear Clara (Club) cells appear

Question 48

What are alvoeli

Answer 48

Sac like pockets lined by simple squamous epithelium Type 1 pneumocytes Type 2 pneumocyte

Question 49

What is a type 1 pneumocyte

Answer 49

Squamous alveolar cell 97% of alveoli

Question 50

What is a type 2 pneumocyte

Answer 50

Septal cells 3% of alveoli Produce surfactant Reduce surface tension

Question 51

What are the four layers of the GI tract

Answer 51

Mucosa Submucosa Muscularis Externa Serosa/adventitia

Question 52

What is the mucosa

Answer 52

Epithelium

Question 53

What is the submucosa

Answer 53

Connective tissue + blood vessels + glands

Question 54

What is the muscularis externa of the GIT

Answer 54

Inner circular muscle Outer longitudinal muscle

Question 55

What is the serosa/adventita

Answer 55

A serous membrane inside the body cavity A loose layer of CT outside the body cavity