Introduction to Cellular Pathology

Question 1

What is a histology?

Answer 1

Histology is the study of tissues and their structure

Question 2

Recall the different organisations of different structures

Answer 2

• Tissue structure - how cells combine with extracellular material and each other to form a tissue
• Cellular structure - how a cell is shaped, and how the components inside cells are organized to support that cells specific function
• Sub-cellular structure - detailed analysis of organelles and inclusions
• Histochemical structure - molecular analysis of cellular structure

Question 3

What is histopathology?

Answer 3

• the study of tissues affected by disease.
• Useful in making a diagnosis and in determining the severity and progression of a disease.
• Understanding the normal structure and function of different tissues is essential for interpreting the changes that occur during disease.

Question 4

What do histopathology guidelines summarise?(3)

Answer 4

o The types of tissues observed in the human body.
o The classification of the different sub-types for each tissue.
• The embryological origin of each tissue

Question 5

Describe epithelial tissue

Answer 5

• Is made of cells arranged in a continuous sheet with one or more layers; has apical & basal surfaces.
o A basement membrane separates the epithelial layer from the underlying connective tissue.

Question 6

Name the two types of epithelial tissues

Answer 6

1) Covering & lining epithelia;

2) Glandular epithelium (endocrine and exocrine).

Question 7

How are epithelial tissues classified?

Answer 7

o The number of cell layers & the shape of the cells in the top layer

Question 8

How are cell layers classified?(3)

Answer 8

• Simple Epithelium - one cell layer.
• Stratified Epithelium - two or more cell layers.
• Pseudostratified Epithelium - cells are all anchored to the basement membrane (i.e. one cell layer) but not all cells reach the apical surface (nuclei do not align, does not look like one cell layer).

Question 9

What are the three types of shapes of cell layers?

Answer 9

 Cuboidal, columnar, squamous

Question 10

What are the two main groups of connective tissue?

Answer 10

1) Connective tissue proper; 2) Specialized connective tissue.

Question 11

What is the connective tissue made of?

Answer 11

1) ground substance - proteins and polysaccharides;

2) fibres – reticular, collagen and elastic.

Question 12

What types of cells can be found in connective tissues?

Answer 12

o Many different cell types including fibroblasts, macrophages, mast cells, and adipocytes.

Question 13

How are connective tissue proper classified?

Answer 13

o Loose Connective – fibres & many cell types in gelatinous matrix, found in skin & surrounding blood vessels, nerves and organs.

o Dense Connective – bundles of parallel collagen fibres & fibroblasts, found in tendons and ligaments. No space in between

Question 14

What two components make up cartilage?

Answer 14

) collagen & elastin fibres embedded in a matrix of glycoproteins;

2) cells called chondrocytes

Question 15

What are the three types of cartilages?

Answer 15

o Hyaline cartilage – Weakest, most abundant type. Found at end of long bones, & structures like the ear and nose.

o Elastic cartilage - maintains shape, branching elastic fibers distinguish it from hyaline.

o Fibrous cartilage - Strongest type, has dense collagen & little matrix, found in pelvis, skull & vertebral discs.

Question 16

What is the bone composed of?

Answer 16

• Bone is composed of bone cells - osteoprogenitor cells, osteoblasts, osteocytes and osteoclasts – suspended in a matrix consisting of collagen fibres and minerals (opposite to cartilage).

Question 17

In bone development what is the difference between endochondral and membranous?

Answer 17

1) Membranous – as in flat bones, clavicle, or mandible;

2) Endochondral – as in limb and vertebral column bones.

Question 18

Mature bone can be divided into…

Answer 18

1) Compact – concentric circular layers (lamellae) organized in lacunae and a central canal (Harvesian system);
2) Trabecular – slender interlacing parallel lamellae with marrow within the spaces.

Question 19

Describe skeletal muscle(3)

Answer 19

voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones.

Organized in myofibers with nuclei peripherally located.

Forms a lined-up banding pattern from one cell to another when observed longitudinally.

Question 20

What is cardiac muscle?

Answer 20

involuntary, striated, branched, and has intercalated discs. Cells smaller than skeletal muscle with nuclei centrally located.

Question 21

Describe smooth muscle

Answer 21

– involuntary, non-striated, spindle shaped and is found in blood vessels & the GI tract. Cells vary in size and have a fusiform shape. Nuclei observed in different positions.

Question 22

What is neurologia and what is it made up of?

Answer 22

collection of different cell types with supportive role to the neurons.
2. made up of astrocytes, oligodendrocytes, ependymal cells and microglia in the CNS, and Schwann cells and satellite cells in the PNS.

Question 23

What is the different types of neurons?

Answer 23

• Motor Neuron – carry impulses from CNS to muscles and glands.
• Interneuron - interpret input from sensory neurons and end responses to motor neurons.
• Sensory Neuron – receive information from environment and transmit to CNS.

Question 24

What are the three stages of development in all tissues?

Answer 24

• Ectoderm - develops into nervous tissue and epithelial tissue.
• Mesoderm – develops into epithelial tissue, connective tissue and muscle tissue.
• Endoderm – develops into epithelial tissue.