ANATOMY & PHYSIOLOGY OF SKIN AND HAIR

1. Draw and label a diagram of the Epidermis.

2. Draw and label a diagram of the dermal and subcutaneous layer Of the skin

Please make sure that you include all the things from the table below.

3. Fill in the following table:

STRUCTURE POSITION FUNCTION
Papillary layer Upper layer of dermis Provides nutrients for the living cells of epidermis Reticular layer Second layer of dermis Collagen, elastic & reticular fibbers gives skin strength elasticity and support which all help to maintain skin’s tone.

Subcutaneous layer Situated below the dermis, consists of Adipose tissue(fat) and areola tissue Adipose tissue protects against injury and insulates keeping body warm. Areola tissue elastic fibbers making layer strong and flexible Eccrine glands Coiled tubular glands open directly onto skins surface Regulate body temperature, help eliminate waste Apocrine glands Connected to hair follicles, only found in genital and underarm regions Produce a fatty secretion. Breakdown of secretion by bacteria and leads to body odour Hair follicles Sac or sheath of epidermal cells and connective tissue, surrounds root of hair Holds hair in place and enclose the hair shaft, provides hair with vital nourishment – contains dermal papilla which supplies blood to hair Sebaceous glands Small sac-like pouches Produce an oily substance known as Sebum (contains fat, cholesterol and cellular debris) coats surface of skin and hair shaft preventing excess water loss

Arrector pili Smooth muscle of sensory fibbers attached at angle to base of hair follicle Makes hair stand erect in response to cold or experiencing emotions as fright and anxiety Blood vessels Runs through dermis and subcutaneous layers Brings nutrients and oxygen to germinating cells in the epidermis and remove waste products. Sensory nerve ending All over body more on finger tips and lips Stimuli sends messages through sensory nerves to brain – aware of pain, touch, heat and cold Motor nerve ending dermis Transmit impulses to the effector organs: muscles and glands. Capillaries Throughout dermis and subcutaneous layer The site of where exchange of substances between blood and body tissues take place

4. List and discuss the functions of the skin
Sensation: contains sensory nerve endings which send messages to the brain. A nerve respond to touch, pressure, pain, and cold, hot and allows us to recognise things from their shape and feel. Heat regulation: regulates body temperature by –

• Losing too much heat the blood capillaries near skins surface contract, keeping warm blood away from skins surface and closer to major organs. • When body is too warn blood capillaries dilate allowing warm blood to flow near skins surface to cool the body. • Evaporation of sweat from skins surface also assist in the cooling of the body. • Arector pili muscles raise hairs and trap air next to the skin when heat is needed to be retained. • Adipose tissue of the dermis and subcutaneous layers help insulate body against heat loss. Absorption: skin is mostly waterproof and has limited absorption properties. However substances which the epidermis can absorb include fat soluble substances such as oxygen, carbon dioxide, fat soluble vitamins, steroids, along with small amounts of water. Protection: acts as a protective organ –

• Fat cells of the subcutaneous layer protect bones and major organs from injury. • Melanin – produced in basal layer, helps protect the body from harmful effects of ultra violet radiation. • Cells located in the Horny layer overlap like scales prevent micro-organisms penetrating the skin and prevent excessive water loss from body. • A film of sebum and sweat o...

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