T1L8: Introduction to Microscopic Anatomy

Question 1

Stratified squamous epithelium [4]

Answer 1

Stratified → cells pile on top of each other
Squamous → cells are flat

Stratification is necessary at sites of friction with the risk of mechanical damage
Squamous epithelium in internal organs appears white on naked eye examination

Question 2

Keratin

Answer 2

Protein present in skin cells
Produced by keratinocytes
Stratified squamous epithelium either keratinised or not

Question 3

Squamous epithelium lines [6]

Answer 3

• Skin
	• Mouth and tongue
	• Oesophagus
	• Anal canal
	• Vagina
Cervix

Question 4

Columnar epithelium

Answer 4

• More diverse than squamous epithelium:

• Columnar epithelium appears pink/red in organs on naked eye examination  Secrete mucus  and function  depends on the organ

tall and have elongated nuclei

Test tube like structures - crypts

Question 5

Columnar epithelium lines

Answer 5

○ - Respiratory tract→ trachea & bronchi

○ - Gastrointestinal tract→ stomach, small & large intestines

Question 6

Columnar epithelium roles

Answer 6

○ Protects the lining(T) - in the stomach
Traps dust particle (T) - respiratory tract
Acts as lubricant (T) - large bowel and female genital tract

Question 7

Microvilli

Answer 7

Increase SA

Lined by columnar cells with goblet cells

Question 8

Oesophagus

Answer 8

joined to the stomach at the oesophago-gastric junction (OGJ) and lined by Non-keratinised stratified squamous epithelium

Question 9

Upper respiratory tract

Answer 9

Part of the larynx, trachea & bronchi are lined by pseudo-stratified columnar epithelium

Question 10

Pseudostratified Ciliated Columnar Epithelium

Answer 10

• Pseudostratified - because all nuclei do not reach the surface
• The surface shows fine finger-like structures termed cilia
• Line the respiratory tract To trap dust particles (T)
N.B. The cilia, in conjunction with mucus secreted by the cells where the cilia are attached, trap dust particles to stop them getting to the lungs.

Question 11

Cuboidal cells

Answer 11

• Found in glands which secrete specialised fluids, i.e.
○ Salivary glands
○ Sweat glands
○ Endocrine glands secrete hormones
○ Breast produces secretion
On microscopy the white tissue appears pink and consists of fibrous tissue which supports the breast glands.
A single breast gland is lined by cuboidal cells (more round than a cube); the lumen contains milk.

Question 12

Skeletal muscle

Answer 12

• Cells or fibres run parallel to each other
• The cells contain multiple lines termed striations which run perpendicular to the long fibres
Striations are important for the contractile function of the muscle cells

Question 13

Cardiac muscle

Answer 13

• Cells are joined together at irregular junctions termed intercalated discs which resemble a jagged edge
• Intercalated discs are important for the contractile function of the heart
• Cardiac muscle also contains striations
Brown pigment is end product of break down of the muscle (wear and tear) called lipofuschin

Question 14

Fat function

Answer 14

§ P for Protection
§ I for Insulation
§ E for Energy source

Question 15

Fibrous tissue

Answer 15

• Important connective tissue due to its strength e.g. tendons
  
  • Important in healing of wounds to form scars
  • Consists of long fibres containing collagen
  • Fibroblasts produce the protein collagen
  • In healed wounds, scar tissue and fibrous tissue are used interchangeably

Fibrous tissue consists of elongated fibres produced by fibroblasts. The fibres are tightly packed together for maximum strength. Ignore the white spaces – they are artefacts from processing