Chapter 5: Integumentary System

Question 1

Why is skin an organ?

Answer 1

Because it is
- composed of several types of tissues
- performs specific functions
- vascular
- innervated

Question 2

What are the seven integument functions?

Answer 2

1. Protection
2. Prevention of water loss or gain
3. Temperature regulation
4. Metabolic regulation
5. Immune defence
6. Sensory reception
7. Secretion

Question 3

Describe The structure of skin

Answer 3

• Epidermis: outer, thinner layer - epithelial
• dermis: inner, thicker layer - connective
• Hypodermis/subcutaneous: beneath the dermis and attaches the skin to the underlying tissues or organs

Question 4

What are the cell types in the epidermis?

Answer 4

• keratinocytes (85%)
• melanocytes (8%)
• Intraepidermal macrophages/Langerhan cells (5%)
• tactile/Merkel cells (2%)

Question 5

What are the 5 layers of the epidermidis from deep to superficial

Answer 5

1. Stratum basale
2. Stratum Spinosum
3. Stratum granulosum
4. Stratum luciclum
5. Stratum corneum

Question 6

What are the properties of stratum basale?

Answer 6

• cuboidal/columnar in a single row
• nuclei are large and there’s a large amount of cell organelles, but small mitochondria
• made of melanocytes and Merkel cells

Question 7

What are the properties of stratum Spinosum?

Answer 7

• several layers of polygonal keratinocytes
• made up of immune cells that act as phagocytes

Question 8

What are the properties of stratum granulosum?

Answer 8

• 3 to 5 layers of keratinocytes
• Lamellar granules release contents to help form the water barrier

Question 9

What are the properties of stratum luciclum?

Answer 9

• thin, clear, and only 2 to 3 cells thick
  -present only in thick skin (palms and soles)

Question 10

What are the properties of stratum corneum?

Answer 10

• 20 to 30 layers of dead, scaly, interlocking cells called corneocytes
• Will eventually shed

Question 11

How is skin colour determined?

Answer 11

By three pigments:
1) hemoglobin: red in colour
2) melanin: pigment produced by melanocytes
3) carotene: yellow/orange from foods (carrots, squash…)

Question 12

What are the six skin markings?

Answer 12

1) Nevus (mole): localized overgrowth of melanocytes
2) freckles: yellow or brown spots of high melanocyte activity
3) hemangioma: proliferation of blood vessels that form a benign tumour
4) capillary hemangiomas: bright, red to dark purple (appear in childhood)
5) Cavernous Hemangiomas: large, dermal vessels
6) friction ridges: skin texture, (e.g., fingerprints)

Question 13

Describe The connective tissue in the dermis

Answer 13

Contains collagen, elastic, and reticular fibres for tensile strength, as well as sweat glands, sebaceous glands, hair follicles, nerve endings, and smooth muscle

Question 14

What are the two layers of the dermis?

Answer 14

1) papillary layer: interlocks with epidermal ridges, and contains capillaries
2) reticular layer: large collagen, boundaries; includes glands, blood vessels, hair, follicles, and nerves

Question 15

What are lines of cleavage?

Answer 15

Tension lines (incisions across lines of cleavage heal slower than with the lines)

Question 16

How do Stretch marks form?

Answer 16

Skin is overstretched -> collagen fibres tear -> striae form

Question 17

Describe the SubQ layer

Answer 17

Functions: protect, store energy, and thermal insulation
Composition: areolar and adipose tissue

Question 18

What are the 3 types of hair?

Answer 18

1) Lanugo: on fetus
2) Vellus: fine and non pigmented and is on most of the body
3) terminal: coarse and pigmented

Question 19

What are the 4 functions of hair?

Answer 19

1) protection
2) heat retention
3) sensory reception
4) visual identification

Question 20

What are the 3 layers of hair?

Answer 20

1) medulla: core of loose cells
2) cortex: layers of hardened flat cells
3) cuticle: outer coating