Module 5 - Integumentary

Question 1

Identify the three layers of the skin in order

Answer 1

Epidermis, dermis, hypodermis

Question 2

Identify the five layers of the epidermis

Answer 2

1. stratum corneum - outer most layer
2. stratum lucidum - second layer
3. stratum granulosm - third layer
4. stratum spinosum - white nuclei
5. stratum basale - bottom layer

Tip: “Come Lets Get Sun Burnt”

Question 3

Describe the stratum corneum

Answer 3

1. outer most layer of epidermis
2. composed of corneocytes
3. these cells serve as protective barrier against environmental factors
4. continually sheds dead cells, replacing them with new cells from lower layers

Question 4

Describe the Stratum lucidum

Answer 4

1. second layer of epidermis
2. translucent
3. found in thick skin of palms and soles
4. composed of keratinocytes

Question 5

Describe Stratum granulosum

Answer 5

1. third layer of epidermis
2. contains proteins that help form keratin
3. plays role in dehydration and hardening of keratinocytes

Question 6

Describe stratum spinosum

Answer 6

1. composed of layers of keratinocytes which are connected by desmosomes
2. desmosomes provide mechanical strength to epidermis
3. this layer also contains dendritic cells which are involved in immune response

Question 7

Describe stratum Basale

Answer 7

1. Deepest layer of epidermis
2. in direct contact with underlying dermis
3. contains single layer of cuboidal stem cells which divide to produce new keratinocytes
4. responsible for skin regeneration + repair

Question 8

Identify the four major cell types in the epidermis

Answer 8

1. keratinocytes
2. Melanocytes
3. Intraepidermal macrophages (langerhan’s cell)
   4.Tactile epithelial cells (Merkel cells)

Question 9

Describe keratinocytes

Answer 9

*Develop in basal layer and move up to top layer
*protection to stop pathogens and UV and physical injuries
*Keratin production for strength and flexibility of skin
*Waterproofing – produces lipids to prevent water loss

Question 10

Describe Melanocytes

Answer 10

*Important for protection as they protect DNA within keratinocytes from UV damage

Question 11

Describe Intraepidermal Macrophages (Langerhans Cells):

Answer 11

• type of immune cell
• they capture microbes/allergens that come into contact with the skin
• They serve as a crucial component of the skin’s defense against pathogens and play a role in allergic responses.

Question 12

Describe Tactile Epithelial Cells (Merkel Cells):

Answer 12

1. located in the stratum basale
2. They are involved in the sensation of touch.
3. Merkel cells form synapses (connections) with sensory nerve endings in the skin and play a role in detecting pressure, texture, and shapes.
4. These cells are particularly abundant in areas of the body where fine touch discrimination is important, such as the fingertips.

Question 13

Identify conditions that arise when there is a disruption in homeostasis of the major cells in the epidermis

Answer 13

1. Albinism – little or no melanin production (one impacts hair skin and eyes and one impacts only eyes)
2. Vitiligo – patches of skin lose their pigment (cow look) ; autoimmune response, genetic factors, oxidative stress, neural
3. Skin cancer – basal cell carcinoma, squamous cell carcinoma, malignant melanoma

Question 14

Describe the sensory function of the skin

Answer 14

1.Mechanoreceptors – respond to physical changes
2.Thermoreceptors – temperature (cold 25-30, warm 30-46)
3.Nociceptors – pain – only signal at tissue damage

Question 15

Identify the 6 mechanoreceptors of the skin

Answer 15

1. Hair follicles
2. Meissner corpuscles – indentation and slipping
3. Pacinian corpsucles – vibration
4. Merkel complexes – texture understanding
5. Ruffini corpuscles – stretch
6. Tactile epithelial cells – sensitive to touch areas like fingertips, lips, base of hair follicles

Question 16

Describe the components and functions of the dermis, with specificity to the two division

Answer 16

Dermis is composed of connective tissue containing collagen and elastic fibres

Its two regions:
1. Papillary regions
- Lies below epidermis
- Houses capillaries, thermoreceptors, meissners corpuscles
- Responsible for formation of fingertips
- Release growth factors

2. Reticular region
   - Deeper region
   - Dense irregular connective tissue
   - Secures skin
   - Houses larger blood vessels
   - Provides nutrients for skin
   - Plays role in temp regulation

Question 17

Describe the components and functions of the hypodermis

Answer 17

1. Attaches skin to underlying tissue and organs
2. Temperature regulation
3. Stores fat – important for cushioning
4. Energy provisions
5. Important for stretch

Question 18

Describe the structure and function of the hair

Answer 18

Description:
- Present on most surfaces except palms, anterior surfaces of fingers and the soles of feet.
- Composed of dead, keratinized epidermal cells
Genetics determines thickness and distribution

Parts of the hair include:
- The shaft above the skin surface
- The follicle below level of the skin
- A root that penetrates into the dermis
The dermis includes
- Epithelial root sheath
- A dermal root sheath

The function of hair:
- Protection from UV, foreign particles in nasal passage and ears
- Sensory function
- Thermoregulation
- Communication

Question 19

Summarise the life cycle of the hair

Answer 19

1. Anagen phase
   - growth stage
   - 85% of hair present here
   - longer they are here the longer they will grow
2. Catagen phase
   - hair stops growing and becomes detached from the base of the follicle
   - last a few weeks
3. telogen phase
   - 15% of hair in this stage
   - no connection to the root
   - loss

Question 20

Describe the structure and function of the nail

Answer 20

Structure:
1. Made of keratinized epidermal cells
2. free edge, transparent nail body plate with a whitish lunula at its base, nail root embedded in a fold of skin

Function:
protecting digits and contributing to tactile sensation

Question 21

Name and describe the major glands in the integumentary system

Answer 21

1. Sebaceous oil glands
   connected to hair follicles.
2. Eccrine sweat glands
   all over the body. clear, odorless unless theres bacteria, regulate body temp, functional from birth.
3. Apocrine sweat glands
   armpts nipples and genital area. Thicker sweat, odor present, activated by emotional stress, hormonal changes, active around puberty, larger than eccrine glands
4. Ceruminous glands
   modified apocrine glands, work with sebaceous glands to produce ear wax, protects ear canal against physical change and microbial invasion.

Tip: Some Eat Apple Crumble

Question 22

Describe wound healing and differentiate between the two major types

Answer 22

Two kinds of wound healing can occur, depending on the depth
1. Epidermal – heals fast, might not even notice
2. Deep (dermis and subcutaneous layer) – inflammation, proliferative, remodelling

Question 23

Explain what causes aging in the integumentary system

Answer 23

The integumentary system changes with age: * Wrinkles develop.
* Dehydration and cracking occurs.
* Sweat production decreases.
* A decrease in the numbers of functional melanocytes results in gray hair and atypical skin pigmentation.
* Subcutaneous fat is lost, and there is a general decrease in skin thickness.
* Nails may also become more brittle.

Question 24

Describe the classification of burns

Answer 24

1. First-Degree Burns (Superficial Burns):
   - least severe type of burn
   - only affect the epidermis
   - redness, minor pain, swelling
   - healing time: few days to a week
   - usually no scarring
2. Second-Degree Burns
   - affect both the epidermis and the layer beneath it, known as the dermis.
   - redness, blistering, severe pain, and swelling. Blisters may form, and the skin can appear moist or weeping.
   - Healing Time: superficial burns usually within a few weeks and may result in scarring. Deeper second-degree burns may require longer healing time and may also cause scarring.
3. Third-Degree Burns
   - extend through the epidermis and dermis and damage underlying tissues, such as muscles and nerves. - - The skin may appear charred, white, or leathery.
   -These burns often result in numbness because nerve endings are destroyed, although the surrounding area may be painful.
   - Healing is slow and often requires surgical intervention, such as skin grafts. Scarring is significant, and functional and cosmetic impairment is common.
4. Fourth-Degree Burns
   - most severe and extend beyond the skin and into the underlying muscle and bone. The skin often appears blackened and charred, and the damage is extensive.
   - Healing is extremely slow and often requires extensive surgery, including grafts and amputation in some cases. These burns can be life-threatening.

Question 25

Describe deep wound healing

Answer 25

• Deep wound healing occurs when an injury extends to the dermis and subcutaneous layer.
• Three major stages:
  1. Inflammation
  2. Proliferative
  3. Remodeling

Question 26

Describe proliferative Phase of wound healing

Answer 26

Enhanced migration of keratinocytes, fibroblasts, endothelial cells, and leukocytes to the wound area.
1. granulation - by fibroblasts to form collagen
2. epithelialisation - wound closure
3. angiogenisis - formation of new blood cells

Question 27

Describe inflammatory phase of wound healing

Answer 27

• Hemostasis Stage:
• Stabilisation and cessation of bleeding in the wounded area - blood clotting
  –> Vasoconstriction
  –>Platelets adhere to the exposed collagen and other components at the injury site.
  –> Formation of a platelet plug (1)
• Acute Inflammation Stage:
• Release of cytokines and growth factors.
• Migration of leukocytes to the wounded region.

Question 28

Describe remodelling phase of wound healing

Answer 28

• Surge in the activity of Matrix Metalloproteinases (MMPs).
  –> Breaks down temporary structures and creates pathways for cells like fibroblasts and keratinocytes to move

–> occurs 3 or more weeks after injury
1. collagen synthesis and remodelling
* Replacing collagen type III with collagen type I – this is stronger!
* Initiation of apoptosis (programmed cell death) for provisional
* Clears out debris from wound site endothelial cells, fibroblasts, and myofibroblasts in the wound.
2. decreased vascular permeability
3. scar formation –> composed of collagen fibres

Question 29

How sun exposure causes aging

Answer 29

1. UV radiation
2. UV radiation causes collagen breakdown which weakens collagen fibres resulting in loss of skin elasticity and development of fine lines and wrinkles
3. Uv radiation breaks elastin fibres leading to sagging and formation of deep wrinkles
4. photoaging - fine lines, wrinkles, freckles, uneven skin tone
5. blood vessel damage - leading to formation of visible veins on face
6. decreased skin hydration - UV radiation damages skin natural barrier causing it to lose moisture. dry skin = more prone to premature aging

Question 30

Rule of nines

Answer 30

The rule of nines is used to estimate the surface area of an adult affected by a burn. It allows rapid assessment, treatment decisions, and is a predictor of patient outcomes and mortality.

Question 31

Factors affecting wound healing

Answer 31

1. age
2. infection
3. medication
4. medical conditions
5. wound characteristics
   6.psychological factors (stress)