Histology

Question 0

Layers of the epidermis (5)

Answer 0

Top to bottom:

1. Stratum corneum
2. Stratum lucidum (only in thick skin)
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale

Question 1

Functions of integumentary system (6)

Answer 1

1. Forms a tough protective barrier
2. Energy reservoir: adipose tissue in subcutaneous layer
3. Initiate an immune response
4. Site of wound healing
5. Excretion of metabolic products
   6.

Question 2

Histology of Psoriasis

Answer 2

• Acanthosis (epidermal hyperplasia: abnormally thick)
• Parakeratosis (nuclei retention in the stratum corneum)
• Munro microabcesses: collections of neutrophils in the stratum corneum
• Thinning of the epidermis above elongated dermal papillae (results in Auspitz sign)

Question 3

Histology of Lichen Planus

Answer 3

inflammation of the dermal epidermal junction with a saw-tooth appearance

Question 4

Pemphigus Vulgaris

Answer 4

• Suprabasal blisters
• acantholysis (separation) of stratum spinosum
• Basal layer has tombstone appearance
• Immunofloresence highlights IgG surrounding keratinocytes (fish net appearance)

Question 5

Visual features of a motor neuron?

Answer 5

Multi-polar (many dendrites, but only ever one axon), large, pale nucleus (un-condensed DNA), obvious nucleolus.

Question 6

Visual identification of an astrocyte

Answer 6

Cytoplasmic process ends on a blood vessel or a capillary

Question 7

What makes myelin in CNS vs PNS?

Answer 7

CNS: oligodendrocyte
PNS: Schwann cells

Question 8

Which layer of connective tissue is particularly important for the blood/brain barrier?

Answer 8

Perineurium

Question 9

Ganglia

Answer 9

Where ALL the nerves and neuronal cell bodies in the PNS are found.

Question 10

Endoneurium

Answer 10

Found within the nerve bundle

Question 11

How to differentiate dense connective tissue from neural tissue?

Answer 11

Both have an organized, wavy appearance, but neural tissue has spaces that represent the nodes of Ranvier.

Question 12

Capsule/satellite glial cells

Answer 12

Protective function, support for neuronal cell bodies

Question 13

Nissle bodies

Answer 13

• granular, basophilic substance found in neurons (esp large neurons)
• made up of rough ER
• site of protein synthesis

Question 14

What are the distinguishing features between basal and squamous cell carcinoma?

Answer 14

• Squamous cell carcinoma lacks the palisading seen in basal cell carcinomas.
• Squamous cell will show many odd looking cells mixed in with some mature keratinocytes (originated higher in the epidermis).

Question 15

What is the histological hallmark of melanoma?

Answer 15

A nest of melanocytes, distinguishable because they tend to be wrapped in a pale bubble.

Question 16

What immunohistochemical stains are used to diagnose melanoma, and to what specifically do they bind? (2)

Answer 16

1. HMB-45 (marker of melanocytes, positive looks like red granules)
2. S-100 (a calcium binding protein present in melanocytes)

Question 17

Distinguish melanoma from nevi histologically.

Answer 17

Benign nevi show mature keratinocytes with no other oddballs mixed in, and no mitosis.

Question 18

What are the two stains used to identify fungal stains?

Answer 18

GMS and PAS.

Question 19

Glassy bodies are characteristic in histology of what diagnosis?

Answer 19

Molluscum contagiosum

Question 20

How are purkinje fibers distinguished from cardiac muscle?

Answer 20

Purkinje fibers stain paler.

Question 21

How do you distinguish cardiac and skeletal muscle (both striated)?

Answer 21

The nuclei are on the periphery in skeletal muscle (many nuclei) while cardiac muscle nuclei are in the center (1 or 2 nuclei). Cardiac muscle also branches.

Question 22

Where are neurons always found in the periphery?

Answer 22

In a ganglion.

Question 23

What is distinctive about the nucleus in smooth muscle?

Answer 23

It assumes a corkscrew shape when the muscle contracts because it gets caught in the middle.