Integumentary System

Question 1

Name the different sections of hair

Answer 1

Hair root - nourished by blood vessels, has growth phases.

Hair follicle - below the epidermis

Hair shaft - above the epidermis

Hair loses pigment as we age. We also lose more hair than we grow as we age. Hair helps to prevent loss of heat from the head. Hair is made of keratin.

Question 2

Name the glands of the epidermis

Answer 2

Eccrine sweat gland - for cooling the body

Apocrine sweat gland - axillary and anogenital areas only

Sebaceous gland - secretes oil onto the skin and hair to soften and lubricate

Question 3

How is melanoma detected?

Answer 3

A - asymmetry
B - border irregularity 
C - colour (multicoloured. Black, brown, tan, blue and red
D - diameter larger than 6mm
E - evolution. Changes over time

Question 4

The three main skin cancers

Answer 4

Basal cell carcinoma - least malignant and most common. Basal cells invade the dermis. 99% effective treatment by excision. Slow growing and rarely metastasise before discovery. Translucent elevated lesions

Squamous cell carcinoma - rapid growth and metastasis. Red and scaly. From the stratum spinosum. Keratinocytes.

Melanoma - melanocytes. Highly metastatic. Resistant to chemo.

Question 5

Cells of the epidermis

Answer 5

Keratinocytes

Melanocytes

Dendritic cells (aka Langerhans cells - immune cells - phagocytes)

Tactile cells (aka Merkel cells)

Question 6

The integumentary system consists of?

Answer 6

Skin (aka epidermis, aka cutaneous membrane)

Hair

Nails

Cutaneous glands

Question 7

Layers of the epidermis

Answer 7

Stratum basale - basal layer. Continuously replicating

Stratum spinosum - spiny layer

Stratum granulosum - granular layer. Keratinocytes start to die and fill with keratin

Stratum lucidum - clear layer

Stratum corneum - horny layer. Layers of dead cells with thickened membranes, protecting those underneath

Question 8

Functions of the integumentary system

Answer 8

Protection - chemical, physical, biological barrier

Body temperature regulation

Cutaneous sensation

Metabolic functions - vit D

Blood reservoir

Excretion

Question 9

Theory of Water Immersion Wrinkling

Answer 9

• Only occurs in hands and feet, likely because of the abundance of sweat glands and lack of hair
• Sebum is washed away
• Water enters via sweat ducts
• Water causes electrolyte imbalance
• Nerve fibres respond, cause vasoconstriction
• Leads to a downward pull on overlying skin, causing wrinkles.
• People with nerve damage don’t experience this

Question 10

Organ Systems

Answer 10

• Circulatory system
• Respiratory System
• Integumentary System
• Immune System
• Reproductive System
• Digestive System
• Urinary System
• Excretory System
• Central Nervous System
• Peripheral Nervous System
• Endocrine System
• Musculoskeletal System

Question 11

Layers of the skin

Answer 11

• Epidermis, top layers, made up of epithelial cells. Lacks blood.
• Dermis, separated into the papillary layer (below the epidermis) and the reticular layer. The dermis is innervated and vascular, made of collagen fibres. Cleavage lines between the collagen fibres.
• The hypodermis, or subcutaneous layer, is NOT part of the skin.

Question 12

Nerves in the skin

Answer 12

• Lamellar corpuscle = mechano-receptor. Senses pressure

- Tactile corpuscle = mechano-receptor that senses touch.

Question 13

The Rule of Nines

Answer 13

Related to burns

• 11 areas of 9% (99%)
• 9% head and neck (burns to the face are incredibly dangerous because the swelling can cause respiratory failure.
• 18% upper limbs (9% each)
• 36% lower limbs (9% each for each thigh and each lower leg)
• 36% for trunk
• 1% is genitals

Question 14

Burn categorisation

Answer 14

• First-degree - only damages the epidermis. Sunburn is generally a first-degree burn.
• Second-degree - destroys the epidermis and some of the dermis.
• Third-degree - destroys all the epidermis and dermis. Cannot regenerate. Severe fluid loss.