Lecture 1: Anatomy of the Skin, part 1 Flashcards
What does our skin protect?
Underlying tissues and organs
What does our skin protect our tissues/organs from?
4
- Impact
- Abrasion
- Fluid floss
- Chemical attack
What does are skin excrete? (3)
- Salts
- Water
- Organic wastes
How does our skin excrete substance?
Through integumentary glands
How does our skin help maintain our body temperature?
2
- Insulation
- Evaporative cooling
What are three things produced by our skin?
3
- Melanin
- Keratine
- Vitamin D3
What is the function of Melanin?
Protect underlying tissue from ultraviolet radiation
What is the function of Keratin?
2
- Protects against abrasion
- Acts as water repellent
What is the function of Vitamin D3?
Involved in calcium metabolism
What is Vitamin D3?
Steroid hormone
What is Vitamin D3 converted to?
Calcitriol
What is stored in the skin?
Lipids
Where are lipids stored in the dermis?
Adipocytes
Where are lipids stored in the subcutaneous layer?
Adipose tissue
What can our skin detect? (4)
- Touch
- Pressure
- Pain
- Temperature
What does our skin relay information to?
The nervous system
What can lipid/fat reserves be used for?
Energy
How does skin Anatomy relate to its function or performance?
(4)
- Ageing
- Pigmentation
- Skin cancer
- Tattoo
What are 2 functions of skin pigmentation?
- Protection from UV radiation
- Vitamin D production
Does protection from UV radiation require high or low pigmentation?
High pigmentation
Does Vitamin D production require high or low pigmentation?
Low pigmentation
What is the ‘lowest’ level of biological organisation?
Chemical level
What is the ‘middle’ level of biological organisation?
Cellular level
What is the ‘highest’ level of biological organisation?
Tissue level
What are the 4 tissue-types?
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
What are the functions of
Epithelial Tissue?
(3)
- Covers exposed surfaces
- Lines internal surfaces
- Form secretory glands
What are the functions of Connective Tissues?
3
- Fills internal space
- Provides structural support
- Stores energy
What are the functions of Muscle Tissue?
Contracts to produce movement
What are the functions of Nervous tissues?
2
- Conducts electrical impulses
- Carries information
How many primary layers of Skin are there?
3
What are the 3 primary layers of skin?
- Epidermis
- Dermis
- Hypodermis
What 2 layers compose the Cutaneous membrane?
- Epidermis
- Dermis
What layer composes the Subcutaneous layer?
Hypodermis
What are features of the Epidermis?
3
- Stratified barrier
- Mostly keratinocytes
- No circulation (avascular)
What are features of the Dermis?
2
- Contains protein fibres for strength
- Vascular (nourishes epidermis)
What layers comprise the Dermis?
2
- Papillary layer
- Reticular layer
What layers comprise the Epidermis?
5
- Stratum Corneum
- Stratum Lucidem
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
What Epidermal layer is only found in thick skin?
Stratum Lucidem
What does Reticular layer/structure mean?
Mesh like structure, comprised mainly of collagen
What is the purpose of the wavy Papillary layer/Epidermal ridge?
Increase surface area between Dermis/Epidermis
What are features of the Stratum Corneum (horny layer)?
2
- Dead layer
- Dried-out hard cells with no nuclei
What are features of the Stratum Granulosum (granular layer)?
(2)
Contains granules that promote:
- Dehydration of the cell
- Cross linking of keratin fibres
What are the features of the Stratum Spinosum (spinous, spiny or prickle cell layer)?
(2)
- Desmosomes link cells together
- Cells become increasingly flattened as they move upwards
What are the features of the stratum basale (basal layer)?
2
- Columnar regenerative cells
- As the basal cell divides, a daughter cell migrates upwards to replenish the layer above
What are Keratinocytes?
Cells with large amounts of keratin
What is special about the Stratum Corneum?
It can be completely removed
What does the epidermis act as for keratinocytes?
It acts as a Keratinocyte conveyor
What tissue type dominates the Epidermis?
Epithelial tissue
What are the 2 types of Epithelia?
Simple/Stratified Epithelia
What are the cell types of either simple or stratified Epithelia?
(3)
- Squamous
- Cuboidal
- Columnar
What is the cell structure of the Epidermis?
Stratified Squamous epithelium
What are features of the Dermis?
3
- Not shed
- contain protein fibres for strength
- Vascular (nourishes the epidermis)
What are the protein fibres contained with in the Dermis?
2
Collagen/Elastin
Features of the Hypodermis?
2
- Contains adipose tissue (for insulation)
- Is subcutaneous
Where is ‘thick skin’ found?
Palms of hands and Soles of feet
What are features of ‘thick skin’?
2
- No hair
- Extra epidermal layer
What are the results of ageing skin?
6
- Thin epidermis
- Thin dermis
- Slower skin repair
- Drier epidermis
- Impaired cooling
- Less pigmentation
What causes sagging/wrinkling in ageing skin?
Reduced collagen
What causes a Drier Epidermis in ageing skin?
Less Sebum
What causes impaired cooling in ageing skin?
Less sweat/perspiration
What is a physical result of less skin pigmentation?
2
- Pale skin
- Grey hair
What are physiological responses to skin ageing?
6
- Altered hair follicle and fat distribution
- Fewer active follicles
- Slower skin repair
- Reduced blood supply
- Diminished immune response
- Fewer Melanocytes
What are Melanocytes?
Specialised skin cells that produce Melanin
What does smoking do to skin ageing?
It increases skin ageing
How does smoking effect skin ageing?
3
- ‘Reactive oxygen’ damages collagen and elastin
- Causes vasoconstriction
- Nicotine increases Vasopressin
What is Vasopressin?
A pituitary hormone which increases blood pressure
What are the functions of Skin?
6
- Protect
- Excrete
- Maintain
- Synthesis products
- store
- Detect
What is the largest and most visible organ of the body?
The Skin
What % of body weight is skin?
16%
What is the approximate surface area of skin?
1.5 - 2 square meters
