Anatomy- The Integumentary system

What are the components of the integumentary system?

Skin

Hair

Nails

Glands

(hair, nails, and glands are appendages)

What are the main functions of the integumentary system?

protection

thermoregulation

sensation

metabolism

What are the three layers of the skin?

Epidermis

Dermis

Hypodermis (subcutaneous)

What is the structure of the epidermis?

stratified squamous epithelium

Cells types in the epidermis

keratinocytes, melanocytes, langerhans cells, merkel cells

What layers make up the epidermis?

Basale

Spinosum

Granulosum

Lucidum (palms/soles)

Corneum

Is the epidermis or the hypodermis the youngest in terms of cell types

Hypodermis - contains the newest formed cells

What layer of the epidermis is constantly producing epidermal cells (keratinocytes)?

stratum basale

What layer of the epidermis is responsible for protein synthesis?

stratum spinosum

What layer of the epidermis has intercellular spaces that are filled with lipid-rich material ?

Stratum granulosum

What layer of the epidermis provides thickness and strength to withstand friction?

stratum lucidum

What layer of the epidermis is composed of dead keratinized cells that are continuously being shed?

Stratum corneum

What two layers make up the dermis?

reticular layer and papillary layer

Describe the reticular layer of the dermis. The top or bottom? The thickness? What does it have in it? Surrounded by? Protects?

- Deep/bottom layer

- Thick

- Has blood vessels, glands, hair follicles, lymphatics, nerves, fat cells

- Surrounded by a net-like structure of elastin and collagen fibers

- Protects skin structure and lets it move and stretch

Describe the papillary layer of the dermis. The top or bottom? The thickness? What does it have in it? Surrounded by? Protects?

- Superficial/top layer

- thin

- Contains touch receptors (Meissner Corpuscles), phagocytes, blood vessels (capillary loops)

- Extends to basement layer of epidermis and forms a strong bond with it

What is the function of the hypodermis?

Insulation, energy storage

What structures can be found in the hypodermis?

adipose tissue and blood vessels

How does skin function as a barrier?

Shields body from pathogens, UV radiation, physical injury, water loss

How does skin function in thermoregulation?

Sweat glands and blood vessels help maintain stable body temperature

How does the skin function with sensory input?

Nerve endings in the skin allow us to feel touch, temperature, pain, etc.

How does the skin function as an immune defense?

in the stratum corneum, keratinocytes and lipids form a physical barrier against pathogens

Langerhans cells and dendritic cells are crucial for detecting and eliminating pathogens

How does the skin function in vitamin D synthesis?

Exposure to sunlight leads the skin to produce vitamin D which is essential for bone health and immune function

What is the function of hair as a skin appendage?

Provide insulation, sensory input, protection from UV radiation and physical trauma

What do hair follicles contain?

hair shafts, sebaceous glands, and arrector pili muscles

What are the function of nails as skin appendages?

Protects the end of fingers and toes - important for grasping and manipulation

What is the function of sebaceous glands?

Produce sebum which contributes to moisture and acts as a barrier against pathogens. Lubericates the skin and hair

What is the function of eccrine sweat glands?

Secrete sweat, which helps to regulate body temperature and eliminate waste product

What is the function of apocrine sweat glands?

Secrete a thicker, sometimes scented fluid, which can contribute to body odor and has a role in thermoregulation

What are some examples of clinically significant pathologies of hair follicles (what diseases can we see within hair follicles)?

Alopecia -

Folliculitis -

Pediculosis -

Hirsutism -

Hypertrichosis -

alopecia

hair loss

folliculitis

infections of the hair follicles

pediculosis

lice

Hirsutism

excessive hair growth from endocrine glands (PCOS)

Hypertrichosis

excessive growth of hair (wolf man)

What are some examples of clinically significant pathologies of the nails (what diseases can we see within the nails?)

Onychomycosis - fungal infection

Psoriasis - irregular pitting, splitting, or "oil drop"

Lichen planus - longitudinal ridging and splitting of nails

Alopecia areata - geometric pitting of the nails

Melanonychia - pigmentation of nails

onchomycosis

fungal infection of the nail

psoriasis

irregular pitting

lichen planus

longitudinal ridging

alopecia areata

geometric pitting of the nails

melanonychia

pigmentation of the nails

What are some examples of clinically significant pathologies of the sebaceous glands (what diseases can we see within the sebaceous glands?)

Acne

Seborrheic dermatitis

Sebaceous cyst

What are some examples of clinically significant pathologies of the sweat glands (what diseases can we see within the sweat glands?)

Hyperhidrosis - excessive sweat production

Bromhidrosis - excessive body odor

Anhidrosis - absence of sweating

Hidradenitis suppurativa - chronic skin condition causing bumps, abscess, tunneling in intertriginous areas

What skin layer are abrasions often limited to?

epidermis

What skin layers are involved in lacerations?

dermis or deeper

What skin layer is affected in a superficial (1st degree) burn?

Epidermis only

What skin layers are affected in a partial-thickness (2nd degree) burn?

Epidermis and dermis

Blistering due to a burn is indicative of what degree burn?

Second

What skin layers are affected in a full-thickness (3rd degree) burn?

Epidermis, dermis, subcutaneous tissue

What skin layers are involved in a 4th degree burn?

Epidermis, dermis, hypodermis (subcutaneous) and muscle or bone

Loss of sensation (nerve damage) due to a sunburn is indicative that the sunburn has damaged what layer of skin?

deeper dermis into hypodermis (full thickness burn)

Blistering due to a sunburn is caused by the separation of what two skin layers?

Epidermis and dermis

What is an eschar formation?

full-thickness burn with dead tissue

How are pressure ulcers staged?

Based on how deeply the wound penetrates the anatomical layers

What stage of a pressure ulcer is characterized by having intact skin with non-blanchable erythema?

Stage 1

What stage of a pressure ulcer is characterized by having a partial-thickness loss of the dermis, which may appear as a blister or shallow ulcer

Stage 2

What stage of a pressure ulcer is characterized by a full-thickness loss extending into subcutaneous fat?

Stage 3

What stage of a pressure ulcer is characterized by having a full thickness with exposed bone, tendon, or muscle?

Stage 4

Why would a pressure wound be unstageable?

They are obscured by slough or eschar

What is the role of the epidermis in wounds/burns?

It is the first line of defense

Regenerates in partial-thickness injuries

What is the role of the dermis in wounds/burns?

Determines burn severity and healing potential

Contains vasculature and nerves

What is the role of the hypodermis in wounds/burns?

Involvement signals more severe injuries, poor healing potential

What is the role of hair follicles/sweat glands in wounds/burns?

Serves as sources of epithelial cells in wound healing

What is the role of nerve endings in wounds/burns?

Helps to localize and quantify pain - damage alters sensation

What are examples different infectious dermatological conditions? Bacterial, viral, and fungal.

Bacterial - impetigo, cellulitis

Viral - HSV, HPV

Fungal - Tinea

Ulcerated nodules, common with basal cell carcinoma (BCC) often occurs on sun-exposed areas. Why?

This is the area where basal cells are more active.

Scaly, red plaques or nodules, indicative to what, relate to disrupted function of what type of cells?

Keratinocytes, SCC

What does the ABCDE rule for melanoma correspond to?

Disordered growth of melanocytes in the epidermis and beyond

- asymmetry, boarder, color, diameter, and evolution

Name the structure and the associated cancer that can be found in the epidermis.

Keratinocytes

Basal cell carcinoma

Squamous cell carcinoma

Name the structure and the associated cancer that can be found in the basal layer.

Stem cells

Basal cell carcinoma

Name the structure and the associated cancer that can be found in the spinous layer .

- Differentiating keratinocytes

-

Squamous cell carcinoma

Name the structure and the associated cancer that can be found in the stratum basale (epidermis)

melanocytes

melanoma

Name the structure and the associated cancer that can be found in the Dermis

- blood vessels, nerves

BCC, SCC, and melanoma (melanoma is most common)

Name the structure and the associated cancer that can be found in the appendages.

- hair follicles, sebaceous glands

rare skin cancers called

- adnexal tumors

Describe the predicted behavior and spread of basal cell carcinoma

Usually slow growing

Rarely metastasizes - stays within the epidermis or superficial dermis

Describe the predicted spread of squamous cell carcinoma

Has a greater risk of metastasis, especially if it invades dermis or deeper

Describe the spread of melanoma

Spreads both lymphatically and hematogenously

Breslow depth is critical for prognosis as it is a directly anatomical measurement

What is the Breslow depth?

how deep the melanoma invades into the dermis/subcutaneous layer

What would you expect to see from a biopsy of a basal cell carcinoma

basaloid cells from basal layer

What would you expect to see from a biopsy of squamous cell carcinoma

keratin pearls and intercellular bridges, indicating keratinocyte origin

What would you expect to see from a biopsy of melanoma

atypical melanocytes in the basal layer or invading the dermis

How are surgical margins determined in a skin cancer biopsy?

by understanding how far cancer might extend anatomically

What do treatments of skin cancer aim to do?

Clear the cancer while preserving key anatomical structures (particularly on the face and hands)