practical 2 skin

What is the most common connective tissue fiber found in the dermis?

Collagen

Which type of sweat gland (eccrine or apocrine) is involved in evaporative cooling?

Eccrine glands are involved in evaporative cooling.

. Electrolysis is the process of hair removal by using electric current. Explain how this might destroy the process of hair growth in relation to the hair bulb.

Electrical 'burning' of the hair bulb destroys the vascular supply to the hair thus preventing growth of the hair.

The dermis has two main layers. Which one of these is the most superficial?

papillary layer

What does a piloerector muscle do?

A piloerector muscle contracts, pulling the hair upright.

A subcutaneous injection is inserted in the hypodermal or subcutaneous layer. Based on structures found in the hypodermis and not in the epidermis, why is this a preferred area for administering an injection?

Blood vessels are found in the hypodermis and not the epidermis. Injections in the hypodermis will allow the material to flow into the vessels.

The most superficial layer of skin, made of keratinocytes, is dead and provides a protective barrier. If the keratinocytes were alive at the surface, how could that compromise the protective function of the integument?

If the keratinocytes were alive they could be infected with microorganisms and be transmitted from cell to cell.

What material makes the epidermis tough?

Keratin makes the epidermis tough.

What cell type produces a pigment that darkens the skin?

Melanocytes produce the pigment melanin.

The main organ of the integumentary system is the skin. Name three associated structures in the integumentary system.

Nails, hair, and glands

The release of heat from the body by blood vessels occurs in what main layer of the integument?

dermis.

Hair of the axilla can be considered determinate/indeterminate hair

determinate

What integumentary gland secretes an oil-like substance?

The sebaceous glands secrete sebum, a type of oil.

. Distinguish among Pacinian corpuscles, Meissner's corpuscles and pain receptors in the skin.

Pacinian corpuscles are located deep in the dermis and in the hypodermis. They function to receive the sensation of deep pressure. Meissner's corpuscles are located just underneath the epidermis and function to perceive light touch. Pain receptors are located in the dermis and respond to numerous pain stimuli.

Since hair color is determined by pigment in the cortex and the hair shaft is dead, explain the fallacy of a person's hair turning white overnight.

Sudden shock may cause a radical change in hair color but that occurs in the hair root. It takes time for the hair to grow out and, as it does, it may turn white. The effects take longer than overnight.

Approximately how long does it take for the epidermis to renew itself?

The epidermis renews itself about every six weeks.

Which one of the three layers (epidermis, dermis, hypodermis) is not part of the integument?

The hypodermis is not part of the integument

Tattoos consist of ink injected into the skin. Do you think that the ink is injected into the epidermis or the dermis? What support do you give for your answer?

The ink is injected into the dermis. If it was injected into the epidermis the cells would slough off and the tattoo would disappear in weeks.

The outermost portion of the hair is known as the: a. cuticle b. lunula c. root d. medulla

The outermost portion is (a.) cuticle.

What part of the hair is found on the outside of the skin?

The part of the hair external to the skin is the shaft.