Microanatomy

Question 1

What are the key features of the skin

Answer 1

Sweat pore, sebaceous gland, sweat duct, hair follicle, sweat gland, pacinian corpuscle, arrector pili muscle, free nerve endings, Meissner’s corpuscle, hair shaft

Question 2

What are two synonyms for the hypodermis

Answer 2

Subcutis and superficial fascia

Question 3

What is the function of Meissner’s corpuscle

Answer 3

Touch mechanoreceptor

Question 4

What is the function of pacinian corpuscle

Answer 4

Pressure/ vibration mechanoreceptor

Question 5

What is the function of the arrector pilli

Answer 5

Smooth muscle of arrector pili contracts to pull the hair shaft upright to trap air in and aid insulation

Question 6

What are the two layers of the dermal-epidermal junction

Answer 6

Top layer= stratum basale

Bottom layer= paillary dermis

Question 7

What fibres are located in the papillary dermis

Answer 7

Collagen

Question 8

What junctional complex present in the stratum spinosum is affected in pemphigus

Answer 8

Desmosomes

Question 9

What effect does sunlight have on the skin

Answer 9

Causes skin to age prematurely- damage to skin layers

Question 10

Describe the histological changes in the skin that may account for the differences seen in the skin of the infant and older person

Answer 10

Epidermis thins; loss of matrix and water from the dermis results in wrinkles; loss of elastic and other fibres from dermis (elastosis) results in ‘leathery’ look to skin; hypodermis thins; melanocytes decrease but remaining melanocytes increase in size- ‘age/liver spots’; sebaceous gland produce less sebum- dried appearance of skin; sweat glands produce less sweat

Question 11

Which cells, layers or structures are involved in vitamin D production

Answer 11

Stratum basale/ spinosum

Question 12

Which cells, layers or structures are involved in waterproofing

Answer 12

Stratum corneum

Question 13

Which cells, layers or structures are involved in sensory perception

Answer 13

Pacinian corpuscle

Question 14

Which cells, layers or structures are involved in protection from UV radiation

Answer 14

Melanocyte

Question 15

Which cells, layers or structures are involved in temperature regulation

Answer 15

Sweat duct

Question 16

What is the function of a Merkel cell

Answer 16

Involved in fine sensory perception, also neuroendocrine

Question 17

Why are melanocytes dendritic cells

Answer 17

They are branched and the dendrites transfer the melanin to adjacent epidermal cells

Question 18

Name a disease in which the concentration of salt NaCl is increased in sweat

Answer 18

Cystic fibrosis

Question 19

Why is cystic fibrosis more common in populations in higher latitudes than near the equator

Answer 19

Don’t know advantages of cystic fibrosis trait. Gene may lend resistance to Cholera and other sources of bowel inflammation, diarrhea and dehydration

Question 20

What the key differences between thick and thin skin

Answer 20

Thickness of the stratum corneum and extent of papillary ridges, absence of hair follicles in thick skin, stratum lucidum present in thick skin

Question 21

What are the main histological changes seen in the epidermis in psoriasis

Answer 21

Hyperkeratosis (abnormal maturation of the skin and thickening of the stratum corneum); loss of stratum granulosum or granular layer; epidermal hyperplasia with thickening of the stratum basale and spinosum and elongation of papillary ridges (hyperproliferation); vascular dilation (vessels are abnormal as well); generalised inflammation with lymphocytes in the dermis and epidermis

Question 22

What are the cells, fibres and ground substance found in connective tissue proper

Answer 22

Extracellular matrix; collagen fibres; ground substance; mesenchymal cell; elastic fibres; fibroblast; reticular fibres; blood vessel; macrophage; adipocyte

Question 23

Where are elastic fibres found

Answer 23

In elastic cartilage

Question 24

Where are chondrocytes found

Answer 24

In fibrocartilage

Question 25

What are the 3 types of cartilage

Answer 25

Elastic cartilage, fibrocartilage, hyaline cartilage

Question 26

Name two sites in the body where you would find elastic cartilage

Answer 26

Larynx and auricle of external ear

Question 27

Name two sites in the body where you would find fibrocartilage

Answer 27

Intervertebral disc (annulus fibrosus) and pubic symphysis

Question 28

Name two sites in the body where you would find hyaline cartilage

Answer 28

Articular ends of long bones and trachea

Question 29

In long bone, what is located between the endosteum (inside) and periosteum (outside)

Answer 29

Compact bone

Question 30

What cartilage is located on the end of the proximal epiphysis in compact done

Answer 30

Articular cartilage

Question 31

What is located in the metaphysis of long bone

Answer 31

Red bone marrow and spongy bone

Question 32

What is the inside of long bone called

Answer 32

Medullary cavity

Question 33

What is a BMU (basic multicellular unit)

Answer 33

Local groups of osteoclasts and oesteoblasts

Question 34

What is the function of the BMU

Answer 34

Responsible for bone remodelling

Question 35

What is meant by skeletally immature

Answer 35

Open growth plates

Question 36

What are osteoclasts

Answer 36

Large multinucleate bone cells which absorb bone tissue during growth and healing

Question 37

What are osteoblasts

Answer 37

Cells which secrete the substance of bone

Question 38

What is an osteocyte

Answer 38

A bone cell formed when an osteoblast becomes embedded in the material it has secreted

Question 39

Describe the stages of an injury to the skin with the loss of tissue which heals by second intention

Answer 39

Development of granulation tissue, “organisation”, scar formation, wound contraction