Biology Science 1

Integumentary System

2 Major layers of the skin

1. Epidermis

2. Dermis 

1. Epidermis 

Contains 2 Layers : ( actually 5 layers )

1. Stratum Corneum (outermost layer)

- Also known as " Horny Layer "

- Has Keratinocyte ; Produce Keratin ; Keratin has waterproof property 

- Functions of Keratin > To prevent water loss from the body and Act as a barrier against bacteria 

2. Stratum Germinativum 

- Also known as " Germinative Layer "

- Has Melanocyte ; Produce Melanin 

- Functions of Melanin > Produce skin colour and Protect skin from UltraViolet (UV) Rays

- Finger prints formed by Papillae 

2. Dermis

Contains 6 structures :

1. Blood vessels > Transport oxygen and nutrients and to Regulate body temperature 

2. Nerve > Sensation ( e.g. pain, touch, temperature etc. )

3. Hair and Hair follicle 

4. Arrector Pill Muscle > Involuntary muscle. Contraction of muscle can develop ' goosebumps '

5. Sebaceous gland > Produce SEBUM. Keep skin moist and soft. Prevent hair from brittle 

6. Swear gland > Regulate body temperature

Function of the Skin 

[ STaMP ]

S > Sensation ( Sensory Perception )

T > Temperature (Thermoregulation )

M > Metabolism 

P > Protection 

Body response to HOT Stimuli 

1. Blood vessels > Vasodilate > More blood to flow to skin > More heat loss from skin by : Radiation, Conduction and Convection 

2. Sweat glands > Stimulate sweat glands > Produce more sweat > More heat loss by Evaporation 

Body response to COLD Stimuli 

1. Blood vessels > Vasoconstrict > Less blood flow to skin > More blood flow to major organs ( e.g. heart, brain etc. ) > Less heat loss from skin

2. Sweat glands > Inhibit sweat glands > Produce less sweat > Less heat loss by Evaporation 

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