Skin

Question 1

what is emphysema

Answer 1

where elastin and collagen are destroyed. the air goes into the lung, however it gets stuck and can not come out on its own.

bronchioles collapse due to this, and alveolar walls and capillaries are destroyed. less surface area for O2 diffusion.

results in increased respiratory rate, and hypoxemia can develop in the latter stages of the disease

Question 2

define metaplasia

Answer 2

transformation of epithelium into a diff type of epithelium

Question 3

define dysplasia

Answer 3

enlargement of tissue caused by unusual cell proliferations.

Question 4

define adenocarcinoma

Answer 4

malignant tumour formed from glandular structures in epithelium

Question 5

what are the functions of skin

Answer 5

protection, thermoregulation, sensation, secretion, vit D synthesis

Question 6

what are the three layers of skin and their primary structures

Answer 6

epidermis -> keratinocytes
dermis -> dense irregular connective tissue + dermal capillaries
hypodermis -> loose CT and adipose tissue

Question 7

what type of parenteral route is used for administering vaccines

Answer 7

intramuscular

Question 8

what are the major functions of the epidermis

Answer 8

maintain fluid and electrolyte balance
protect from UV light
sensory and immune function

Question 9

what are the 4 layers of the epidermis

Answer 9

stratum corneum, stratum granulosum, stratum spinosum, stratum basale

Question 10

what type of epithelium makes up the epiderms

Answer 10

stratified squamous epithelium

Question 11

write about the stratum corneum

Answer 11

thickest layer - 20/30 cells thick. made of dead cells called corneocytes (final stage of keratinocyte differentiation) which contain keratin.

Question 12

write a bit about stratum granulosum

Answer 12

thin layer, 3-5 keratinocytes thick. granules have glycolipids for waterproofing. cells appear darker in a sample due to the presence of these lipids

Question 13

write about stratum spinosum

Answer 13

these are keratinocytes linked by desmosomes, and have bundles of prekeratin.

Question 14

write about stratum basale

Answer 14

layer closest to dermis- has stem cells and younger keratinocytes

Question 15

what cells may be seen scattered through the epidermis

Answer 15

melanocytes, merkel cell, langerhans cells

Question 16

write about melanocytes

Answer 16

can be found in the stratum basale. they synthesise melanins which are taken up by nearby keratinocytes. they scavenge free radicals which protect against UV.

Question 17

write about merkel cells

Answer 17

found in stratum basale, these are sensory receptors for touch.

Question 18

write about Langerhans’ cells

Answer 18

these are aka epiderma dendritic cells. mainly found in the stratum spinosum. are a type of macrophage. they engulf invading pathogens, and become antigen presenting cells. they can release signalling molecules that attract cells of the immune sys.

Question 19

write about basal cell carcinoma

Answer 19

most common, least dangerous, slow growing. arises from basal keratinocytes.

Question 20

write about squamous cell carcinoma

Answer 20

can metastasize to lymph nodes. derived from mature and differentiated keratinocytes.

Question 21

write about malignant melanoma

Answer 21

most dangerous type, and is developed from melanocytes

Question 22

what are the two layers of the dermis

Answer 22

papillary dermis and reticular dermis

Question 23

write about papillary dermis

Answer 23

includes dermal papilla which project into the epidermis. this increased contact area with epidermis preventing detachment
also responsible for dermatoglyphics (fingerprints).
this layer also has capillaries, free nerve endings and capsulated sensory receptors called meissners corpuscles

Question 24

write about the reticular dermis

Answer 24

area between papillary dermis and the subcutaneous tissue. can find structures such as sweat glands, sebaceous glands, hair follicles and nails.w

Question 25

which part of the dermis has collagen and elastin

Answer 25

reticular dermis

Question 26

write a note on sweat glands

Answer 26

secrete NaCl and water. two types:
- eccrine glands: found everywhere. have a cooling purpose. secretion is slighly acidic - lubrication and antifungal. secretes directly onto the skin

• apocrine gland: found in axilla and anogenital area. secretes onto hair. secretions have fat and protein. involved in bacterial breakdown which causes body odour.

Question 27

write a note on sebaceous glands

Answer 27

secretes oily sebum mainly on hair. is highly bactericidal, and is activated by androgens.

Question 28

write a note on hypodermis

Answer 28

innermost layer, connects skin to underlying fascia of bones and muscle. well vascularised, loose, areolar connective + adipose tissue. is an insulator and shock absorber.