Skin

Question 1

Stratum Corneum

Answer 1

Known as horny layer, it is the outer layer of the epidermis. Contains flat dead keratinised cells. These cells are grayscale desquamated from the skin

Question 2

Stratum Lucidum

Answer 2

Known as clear layer. Cells are flat, contains keratin but have no nuclei. This layer is thin on the face but thicker on palms of hands and soles of feet

Question 3

Stratum Granulosum

Answer 3

Known as the granular layer. The cell nuclei being to break down causing cells to die. The spiny outgrowths become less prominent. The production of keratin starts by the formation of keratohyalin granules

Question 4

Stratum Spinosum

Answer 4

Known as prickle layer. These layers have spiny outgrowths. It is through these outgrowths that melanin granules nether the cells from melanocytes. The stratum germanitivum and this layer are the only living part of the epidermis

Question 5

Dermal Papilla

Answer 5

Situated at the base of the follicle

Enclosed by the hair bulb

Attached to the connective tissue sheath

Has an extensive blood supply

More than one may be present call pili multigemi

Question 6

Sensory nerve endings

Answer 6

These carry nerve impulses from the skin to the brain

They are sensitive to heat, cold, pain, pressure and touch

Question 7

Blood Supply

Answer 7

Bring nutrients and oxygen to the active new cells forming in the epidermis and the removal of waste products

The blood vessels are also invoked in regulating of the body temperature

Question 8

Lymph Vessels

Answer 8

These are found within the dermis and the subcutaneous layers

Lymph vessels are responsible for absorbing toxins, waste and CO2 from the surrounding cells and tissues

Lymph nodes are found within the lymph vessels. They house white blood cells to fight of infection and kill microbes and pathogens that have entered the body and in turn the lymphatic system

Question 9

Hair Follicle

Answer 9

Down growth of the epidermis, lies at an angle. Erector pili muscle is attached to the follicle bulge.

Sebaceous glands are attached and open into the follicle

Question 10

Arrector Pili Muscle

Answer 10

Small bundles of smooth muscle fibres attached to the hair follicles and stimulated by sympathetic nerve fibres in response to fear and cold

Nerve impulses carried from the brain by motor nerves cause the muscles to contract, causing a small bump in the skin allowing the upright hairs to trap a layer of insulating still air near the skin, hence fading the body temperature. This is commonly known as goosebumps. The arrector pili muscle is attached at an angle near the base of the follicle

Question 11

Sebaceous Glands

Answer 11

These glands are found all over the body apart from on the palms of hands and soles of feet. They differ in size, and are much larger on the face, neck and upper chest. They produce sebum which is excreted via hair follicle. Sebum softens and waterproofs the skin, reduces water loss and prevents hair from becoming too brittle, although over production of sebum causes greasy hair and cause spots or acne, if it blocks the hair follicle. It has bacterial action in the follicle and skin, may cause infected area if blocking hair ducts

Sebum has slight antiseptic and fungicidal propertied which help protect the skin. Sebum secretion is stimulated by the production of androgen hormones from the adrenal glands