Week 2 - Integumentary System

Question 1

What is the integumentary System

Answer 1

The skin and its accessory structures

Question 1

What are the layers of the integumentary system

Answer 1

• epidermis
• dermis
• hypodermis

Question 2

What are the cell types in the epidermis (4)

Answer 2

• keratinocytes
• melanocytes
• Merkel cells
• Langerhans cells

Question 3

What are Keratinocyte cells

Answer 3

• The cell which manufactures and stores the protein keratin
• Produces the stratum Basale layer of cells which undergo continous cell division
• Keratinocyte on the surface of the skin is dead

Question 4

What are melanocyte cells

Answer 4

• Spider shaped cells in the stratum Basale
• Synthesizes melanin which forms pigment shields to protect the nucleus from UV damage
• Provides hair and skin its colour

Question 5

What are Merkel Cells

Answer 5

• located in the stratum Basale
• functions as a sensory receptor for touch

Question 6

What are Langerhans cells

Answer 6

• Star shaped cells between keratinocytes
• they ingest foreign substances and activate immune system
• mostly in stratum spinosum

Question 7

What is the acronym for the layers of the epidermis

Answer 7

Can Lemurs Get Some Bamboo

Come Lets Get Sun Burnt

Question 8

What are the layers of the epidermis

Answer 8

1. Corneum
2. Lucidum*
3. Grandulosum
4. Spinosum
5. Basale

Question 9

What is the Stratum Corneum

Answer 9

• Outermost epidermal layer
• Dead cells
• essentially flat membranous sacs filled with keratin
• Protects from abrasion and biological and chemical assaults
• function - waterproofing and protection

Question 10

What is the Stratum Lucidum

Answer 10

• Smooth seemingly translucent layer of the epidermis
• 2nd layer
• Only found in the thick skin of palms, soles and feet
• dead and flattened keratinocytes (cells)
  function - extra stretch
• packed with eleiden, a clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent (i.e., lucid) appearance

Question 11

What is Stratum Grandulosum

Answer 11

• nuclei and other organelles disintegrate as the cells die leaving behind keratin (causing it to look grainy?)
• start of waterproofing and keratin production
• grainyappareance due to keratohyalin and lamellar granules (secrete water resistant glycolpids)

Question 12

What is Structum spinosum

Answer 12

Function - tension resisting and start of keratin synthesis
Includes langerhands cells
Keratinocytes begin synthesis of keratin

Question 13

What is Stratum Basale

Answer 13

• The deepest epidermal layer and attaches the epidermis to the basal lamina below which lies the dermis
• Consists of 1 layer of mitotic stem cells - where one daughter cell pushed into more superficial layers
• Cells are constantly going through mitosis to produce new cells
• Melanocytes and occasional Merkel cells at epidermal - dermal junction

Question 14

What are the layers of the Dermis

Answer 14

1. Papillary Dermis
2. Reticular Dermis
3. Hypodermis

Question 15

What does the dermis contain

Answer 15

• Blood and lymph vessels
• Nerves
• Appendages, hair follicles, nails, glands

Question 16

What is the papillary Dermis

Answer 16

• Thin sheet of areolar connective tissuewhich projects into the stratum Basale of the epidermis to form finger like dermal papillae
• Contains Meissner corpuscles which are free nerve endings and touch receptors
• Contains abundant small blood vessel

Question 17

What is the Reticular Dermis

Answer 17

• Makes up of 80% of the dermis
• Made up of dense irregular connective tissue (elastin and collagen fibers)
• Rich sensory and sympathetic nerve supply
• Contains elastin fibres for elasticity of the skin enabling movement
• contains collagen fibres to provide structure and strength, collage also binds water to keep the skin hydrated

Question 18

What is the hypodermis

Answer 18

• Above the connective tissue wrapping skeletal muscles - not a part of the skin
• well vascularized loose areolar connective tissue and adipose tissue
• Provides insulation and functions as fat storage(energy storage)*
• loosely anchors the skin to the underlying structures*
• where most of the body fat is stored

Question 19

What are the skin appendages (glands) (3)

Answer 19

• Eccrine glands
• Apocrine glands
• Sebaceous glands

Question 20

What are Eccrine glands

Answer 20

• Sweat Gland
• Found on the surface of the skin (mostly hands and feet)
• Duct opens in pores on skin’s surface
• Primary component of thermoregulation and thus helps maintain homeostasis
• Secretionis hypotonic (contains mostly water), some salt, antibodies, antimicrobial peptide

Question 21

What are Apocrine Glands

Answer 21

• Associated with hair follicles in areas such as armpits and gential regions
• Ducts empty into hair follicles
• In addition to water and salts apocine sweat includes fatty acids and proteins (subject to bacterial decomposition and hence BO)

Question 22

What are Sebaceous glands

Answer 22

• type of oil gland found everywhere except for palms and soles
• Produces sebum secreted into hair follicles
• Sebum helps lubricate and waterproof the skin and hair - prevents water loss from the skin

Question 23

What makes the epidermis waterproof

Answer 23

Glycolipids