Chapter 10 Flashcards
The skin is also known as
Cutaneous membrane or integument.
Two primary layer of skin
And the supporting layer
Epidermis and dermis
Supporting layer is hypodermics
Where is thin skin And describe it
Covers most of body
1-3 mm thick
Smooth and has hair
Where is thick skin and describe it
Soles and palms
4-5 mm thick
Ridged no hair
The epidermis is
The outermost and thinnest primary layer
Epidermis is composed of these 4 cells
Keratinocytes, melanocytes, epidermal dendritic cellsm tactile epithelial cells
Role of keratinocytes and % of the epidermis
90% of cells
Waterproof the outer skin
Melanocytes percentage of epidermis and function
5%
Are pigment producing and filter the UV light
Epidermal dendritic cell function
Play a role in immune response
Tactile epithelial cell function
Sensory role in light touch
5 epidermis cell layers from superficial to deep
Stratum corneum (horny layer) Stratum Lucidum (clear layer) Stratum granulosum (granular layer) Stratum spinosum (spiny layer) Stratum basale/germinativum (base layer)
What is the stratum corneum layer made of
Dead cells filled with keratin
What is the stratum lucidum layer made of
Cells filled with keratin precursor
What does the stratum granulosum contain
Cells with high level of lysosomal enzymes
What does the stratum spinosum contain
Cells rich in RNA
What does the stratum basale/ germinativum contain
Cells undergoing mitosis that will travel to skin surface over 35 days
Cell with specialized protective function
Keratinocytes
What is the dermoepidermal junction
Specialized are between epidermis and dermis
Like a layer of glue holding layers together
Blisters are caused by breakdown of this junction
Describe 4 things about the dermis
Deeper and thicker than epidermis
Composed largely of connective tissue—> gives skin its strength
Cells are scattered further apart than epidermis and there are many fibres in between cells
Contains nerve endings, muscle fibers, hair follicles, sweat and subaceous glands, and rich vascular supply.
2 layers of the dermis
Papillary layer (superficial) and reticular layer (deep)
4 features of papillary (superficial) layer
- parallel rows of dermal papillae
- help bind dermis to epidermis
- basis of fingerprinting
- improves our grip
2 features of reticular layer (deeper)
- network of collagenous and stretchable fibres
- number of elastic fibers decreases with age which contributes to wrinkles
Describe dermis growth and repair
Does not continually shed and regenerate itself as the epidermis does
Fibroblasts begin forming dense mass during heal wounding. If normal tissue doesn’t replace it it turns to scar tissue
What are clevage lines in dermis repair
Patterns formed by the collagenous fibers of the reticular layer of the dermis playing a role in incision healing and stretch marks
The hypodermics layer is also known as the
Subcutaneous layer or superficial fascia
Where is the hypodermics located
Under the dermis
What type of tissue is the hypodermics and what type of connection does it form?
Loose connective tissue
Forms connection between skin and other structures
Hypodermics is made primarily of____ and this provide what 3 functions
Primarily fat
- Insulation of heat
- Alternative energy
3 protective cushion
Where is skin pigment produced and by what?
Produced in stratum basale/germinativum and by cells called melanocytes
What is pigment called and what is its primary function
Melanin
Absorb harmful UV radiation from sunlight to prevent sunburn
What is no melanin called
Albinism
7 functions of skin
Protection Sensation Flexibility Excretion Hormone (vitamin d) prod Immunity Temp regulation
4 descriptions of protection function of skin
- physical barrier to microorganisms (keratin)
- barrier to chemical hazards (keratin)
- prevents dehydration (keratin)
- protects against excess UV exposure (melanin function)
2 descriptions of sensation of skin
Skin acts as a sophisticated sense organ
Somatic sensory receptors detect stimuli that permit us to detect pressure, touch, temperature, pain and other general senses
Meissners corpuscles detect
Light touch
Pacinian corpuscles detect
Pressur
3 descriptions of temp regulation of skin
- heat production from muscles
- 80% of heat loss through skin, 20% through mucousa
- Evapouration at high temperature
Two types of heat loss by skin
Sweat - evapouration
Blood flow to skin - radiation
4 accessory organs of the skin
Hair nails, skin, receptor
Hair growth requires ____
An epidermal tube like structure called a hair follicle
Hair follicle is developed by
Epidermal cells growing down into dermal layer
Describe hair papilla
- where hair growth begins
- cup shaped cluster of cells at base of follicle
________ lies hidden in the follicle
Hair root
Visible part of the hair is called
The shaft
Most hair is ____
Invisible
What three body regions are hairless
Lips, palms and soles
Contractions of what cause goosebumps
Arrest or pili
Nails are produced by….
Epidermal cells over ends of fingers and toes
Visible part of nail is called
Nail body
Root of the nail is hidden by the…
Cuticle
Crescent shaped area nearest the root is called
Lunula
Krause end bulbs are
Skin receptors that fell low frequency vibration and fine touch
Free nerve endings feel…
Pain
Two categories if skin glands
Sudoriferous and sebaceous
3 types of sudoriferous glands
Eccrine and apocrine and crumious
3 fasts of eccrine
Most numerous, important and widespread sweat glands
Produce sweat, eliminated through pores
Assist in body heat regulation
3 apocrine facts
Mostly in armpit and around genitalia
Secretion is thicker/ milky (odor caused by bacterial breakdown)
Include ceremonious glands (make ear wax)
3 facts of crumious glands
Specialized sweat gland
Located in the ear
Make ear wax by mixing their secretions with sebum to protect skin of ear canal from dehydration
5 facts of sebaceous glands (oil)
Grow where hair grows
Secrete oil, or sebum, for hair and skin (ducts open into hair follicles)
Level of secretion increase during adolescence
Amount of secretion is regulated by sex hormone
Sebum in sebaceous gland ducts may darken to form black head
Skin cancer may be ____ or ___ and is _____
Genetic or environmental caused and is most common form of cancer
3 common types of cancer and what percentage of cancer do they account for
- Squamous cell carcinoma\
- Basal cell carcinoma
- Malignant melanoma
95% of cancers
4 characteristics f squamous cell carcinoma
Slow growing
Malignant tumour of epidermis
First appear as hard raised nodules
If left untreated, will grow and metastasize
5 facts of basal cell carcinoma
- Most common type of skin cancer
- Usually on upper face
- Least likely to metastasize
- Small raised lesion
- Erodes in the centre forming a bleeding crater
4 facts of malignant melanoma
Most serious form of skin cancer
Can develop from a benign pigment mole
Develops into a dark spreading cancerous lesion
Risk is significantly higher if two blistering sunburns before the age of 2o
Waning signs of melanoma
A- asymmetry B- border (irregular C- colour (unevenness) D- diameter (more than 6 mm) E- evolving (any changes)
4 Causes of burn are
Sunburn, chemicals, electricity and friction
Recovery from burn depending on
Total area involved and severity or depth of burn
Body burn surface Is estimated by
Rule of 9
11 areas
1% at genetials
18 % for trunk`
9 % for legs each side x2
4.5% for arms each side x2
4.5 for head each side
