Cell types & tissues

Question 1

What are common methods of histology sample collection?

Answer 1

• Cell scraping
• Fine needle aspiration (FNA)
• Punch biopsy
• Surgical biopsy

Question 2

What is fixation and why is it essential?

Answer 2

Fixation preserves tissue in a life-like state by preventing autolysis and degradation, allowing accurate histological analysis

Question 3

How does formaldehyde fix tissue?

Answer 3

By cross-linking proteins via methylene bridges, stabilising cellular structures

Question 4

Consequences of poor fixation?

Answer 4

Tissue distortion, artefacts, poor staining, and potential misdiagnosis

Question 5

Why is paraffin embedding used?

Answer 5

To support tissue so it can be cut into thin sections for microscopy

Question 6

What thickness are routine histology sections?

Answer 6

Approx 5-10 µm.

Question 7

Difference between microtome and cryotome?

Answer 7

Microtome cuts paraffin-embedded tissue; cryotome cuts frozen tissue for rapid diagnosis

Question 8

Why is staining required in histology?

Answer 8

Most tissues are transparent; stains provide contrast to visualise structures.

Question 9

What is the most commonly used histological stain?

Answer 9

Haematoxylin and Eosin (H&E).

Question 10

What does haematoxylin stain and why?

Answer 10

Acidic (basophilic) structures such as DNA and RNA, staining nuclei purple/blue.

Question 11

What does eosin stain and why?

Answer 11

Basic (acidophilic) structures such as cytoplasmic proteins and extracellular fibres, staining them pink.

Question 12

What is Whole Slide Imaging (WSI)?

Answer 12

Digital scanning of entire histology slides at high resolution for virtual microscopy and analysis.

Question 13

Correct approach to analysing a histology image?

Answer 13

Identify tissue at low magnification first, then increase magnification to confirm cell types.

Question 14

What cellular structures can be identified in routine histology?

Answer 14

Cell membrane, cytoplasm, nucleus, nucleolus, chromatin.

Question 15

What does a prominent nucleolus indicate?

Answer 15

High protein synthesis and active transcription.

Question 16

What are mitotic figures and why are they important?

Answer 16

Visible stages of mitosis; indicate cell proliferation and are often increased in tumours.

Question 17

Key histological features of apoptosis?

Answer 17

Cell shrinkage, chromatin condensation, nuclear fragmentation, no inflammation.

Question 18

What are the four basic tissue types?

Answer 18

Epithelial, connective, muscle, nervous.

Question 19

How is epithelium classified?

Answer 19

By number of layers and cell shape.

Question 20

Function of simple squamous epithelium?

Answer 20

Rapid diffusion and filtration (e.g. alveoli, glomeruli).

Question 21

Function of simple cuboidal epithelium?

Answer 21

Secretion and absorption (e.g. glands, kidney tubules).

Question 22

Function of simple columnar epithelium?

Answer 22

Absorption and secretion; often contains goblet cells.

Question 23

Why is stratified squamous epithelium protective?

Answer 23

Multiple cell layers resist abrasion and damage.

Question 24

Where is transitional epithelium found and why?

Answer 24

Urinary bladder; allows stretching without tearing.

Question 25

Main components of connective tissue?

Answer 25

Cells, fibres (collagen, elastic), and extracellular matrix.

Question 26

Function of dense regular connective tissue?

Answer 26

Provides strong tensile strength in one direction (e.g. tendons).

Question 27

Three types of muscle tissue?

Answer 27

Smooth, skeletal, cardiac.

Question 28

Key identifying features of cardiac muscle?

Answer 28

Striations, branching fibres, central nuclei, intercalated discs.

Question 29

Main function of nervous tissue?

Answer 29

Transmission of electrical signals for coordination and control.

Question 30

Why does cell structure reflect function?

Answer 30

Cellular specialisations optimise cells for their specific physiological roles.

Question 31

What is the FIRST step when analysing a histology image?

Answer 31

Look at the image at low magnification to identify the main tissue type (epithelium, connective, muscle, nervous).

Question 32

What should you do AFTER identifying the tissue type?

Answer 32

Increase magnification to confirm cell shape, layering, and special features.

Question 33

Image shows purple nuclei and pink cytoplasm/ECM — what stain is this?

Answer 33

Haematoxylin and Eosin (H&E).

Question 34

In H&E, what structures stain purple and why?

Answer 34

Nuclei (DNA/RNA) because haematoxylin binds acidic structures.

Question 35

Thin, flat cells with flattened nuclei; very thin layer lining spaces — identify the tissue.

Answer 35

Simple squamous epithelium. Key features: Flat cells, minimal cytoplasm Likely location: Alveoli, glomeruli, blood vessels Function: Rapid diffusion/filtration

Question 36

Cube-shaped cells with round central nuclei forming tubules — identify the tissue.

Answer 36

Simple cuboidal epithelium. Key features: Cuboidal cells, circular nuclei Likely location: Kidney tubules, glands Function: Secretion and absorption

Question 37

Tall cells with elongated nuclei; goblet cells may be present — identify the tissue

Answer 37

Simple columnar epithelium. Key features: Tall cells, basal nuclei, goblet cells Likely location: GI tract Function: Absorption and secretion

Question 38

Many layers of cells with flattened surface cells — identify the tissue.

Answer 38

Stratified squamous epithelium. Key features: Multiple layers, flattened surface cells Function: Protection

Question 39

Epithelium with dome-shaped surface cells; thickness varies — identify the tissue.

Answer 39

Transitional epithelium. Likely location: Urinary bladder Function: Stretching

Question 40

Thin lining of flattened cells inside a vessel lumen — what is this called?

Answer 40

Endothelium (simple squamous epithelium).

Question 41

How can you identify a blood vessel in histology?

Answer 41

Presence of a lumen, endothelial lining, and often red blood cells.

Question 42

Parallel collagen fibres with flattened fibroblast nuclei — identify the tissue.

Answer 42

Dense regular connective tissue. Likely location: Tendons, ligaments Function: Tensile strength in one direction

Question 43

Large empty-looking cells with thin cytoplasm pushed to the edge — identify the tissue.

Answer 43

Adipose tissue.

Question 44

Spindle-shaped cells with central nuclei and no striations — identify the muscle

Answer 44

Smooth muscle.

Question 45

Striated muscle fibres with branching cells and central nuclei — identify the muscle

Answer 45

Cardiac muscle Extra feature: Intercalated discs

Question 46

Cluster of large neuron cell bodies with supporting cells — identify the structure

Answer 46

Nerve ganglion.

Question 47

Darkly stained, condensed nucleus; cell shrinkage — what process is occurring?

Answer 47

Apoptosis.

Question 48

Numerous mitotic figures in tissue — what does this suggest?

Answer 48

High cell proliferation (e.g. growth, repair, or tumour).

Question 49

What THREE things should you always state in an image ID answer?

Answer 49

Tissue type, key identifying features, and function.