Flashcards in Chapter 5 (Lecture Objective 3) Deck (23):
What are the two major components of the integumentary system?
The two main components are the skin and its derivatives such as hair, nails, and glands
List the functions of the integumentary system.
The functions of the integumentary system are protection, temperature regulation, metabolic functions, blood reservoir, and excretion.
What type of tissue is the dermis?
The dermis is made up of strong, flexible dense irregular connective tissue
What is the cleavage line, and what is its significance?
A cleavage line is a space in the bundles of collagen that run through the dermis that run parallel to the skin surface within the reticular layer. These are significant for tissue repair. If there was an injury or incision (surgery) that ran parallel to theses lines then it would heal faster and gapes less. Perpendicular incisions would be harder to heal.
What is the effect of sunlight on skin color? Why?
The effect of sunlight on skin is overall skin darkening due to the build up of melanin. Melanin build up is activated by the sun’s stimulation of keratinocytes which activate melanocytes. This is a response to protect the DNA of the skin cells.
Briefly explain why sunburned skin peels rather than being shed as a powder.
Sun burned skin peels because the skins cells are held together by desmosomes which are junctions that tightly hold cells together in order to anchor them during mechanical tension.
What are the two types of sweat glands?
There are two types of sweat glands merocrine and apocrine.
What is acne and how is it formed?
Acne is the inflammation of the sebaceous glands. When there is accumulation of sebum that blocks a sebaceous gland duct a white head forms and when it hardens it becomes a black head. Acne is usually caused by a bacterial infection.
What are ceruminous glands, and what do they produce?
Ceruminous glands are modified apocrine glands that are found on the external ear canal. They produce a secretion that mixes with sebum to form earwax.
What causes male-pattern baldness?
Thought to be caused by a delayed action gene that switches ‘on’ in adulthood and changes the response of the air follicles to DHT (metabolite of testosterone). Follicular growth cycle shortens and most hairs don't emerge from the follicle before shedding.
What are the 3 forms of skin cancer?
Basal cell carcinoma, Squamous cell carcinoma, melanoma.
What is the ABCD rule?
Asymmetry: two sides of the spot do not match
Border irregularity: borders exhibit indentations
Color: spot contains several colors
Diameter: larger than 6mm
These are a set of questions that should be asked about any suspicious looking skin spots.
Describe the rule of nines in burn victims
A method that divides the body into 11 areas, each accounting for 9% of the total body area, plus an additional area around the genitals accounting for 1% of the total body surface area. This is applied in order to determine the total surface area burned in order to estimate the volume of fluid loss.
Describe the following cell types: Merkel cells, melanocytes, basal cells and keratinocytes.
Merkel cells: oval receptor cells found in the skin of vertebrates that have synaptic contacts with somatosensory afferents. They discriminate against light touch signals on the skin.
melanocytes: the sider shaped epithelial cells that synthesize the pigment melanin
basal cells: the epithelial cells that make up the innermost layer of the epidermis
keratinocytes: cells that produce the fibers protein keratin
What are the layers (strata) of the epidermis?
The epidermis is composed of these layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.
What is the function of melanin in keratinocytes?
Melanin forms a photopigment protective layer on the “sunny” side of the keratinocyte’s nucleus in order to protect the DNA from the damaging effects of sunlight.
In a condition known as sunstroke, the victim appears flushed, the skin is warm and dry, and the body temperature rises dramatically. Explain these observations based on what you know concerning the role of the skin in thermoregulation.
The body is dehydrated so sweat is no longer being produced. The flushed skin would be due to blood being pumped to surface which causes vasodilation in order to release heat. But because there is no sweat being produced and evaporating, which carries the heat away, the body temperature continues to rise.
Many medications can be administered transdermally by applying patches that contain the medication to the surface of the skin. These patches can be attached anywhere on the skin except the palms of the hands and the soles of the feet.Why?
The palms and soles have more merocrine sweat glands, which would cause the patch to not stick. This would also make absorption of the medication more difficult. Feet and hands are also high traffic areas of the body that undergo a lot of mechanical stress ie. walking, washing hands, etc. all of which would hinder the medication’s ability to absorb into the body.
Why is a subcutaneous injection with a hypodermic needle a useful method of administering drugs?
Medications are administered into one area of the body but are required to be transported through the organism which requires the circulatory system. The subcutaneous tissue is vascularized tissue therefore it is a tissue that can facilitate a drug moving into the blood for distribution.
Explain why warm, dry climates feel cooler than warm, humid climates, even though the temperatures may be the same.
Humid climates cause sweat evaporation to be more difficult, meaning that less heat is dissipated from the body giving the overall effect of feeling like you're not cooling off.
Why is regional infection or inflammation of the skin usually very painful?
Inflammation of the skin is very painful because Merkel cells are present at the epidermal/dermal junction. These specialized cells are in charge of communicating with the the nervous systems about somatosensory (touch) stimuli. Therefore if the epidermis and dermis are inflamed a touch stimulus will cause the Merkel cells to fire and the body to experience pain.
An 80-year-old grandmother sets her thermostat at 26ºC (80ºF) and wears a sweater on balmy spring days. When asked why, the grandmother says she is cold. Can you give one possible cause for her feeling cold?
One possible reason could be that the subcutaneous fat of the hypodermis may be reduced in an 80-year-old, which makes it difficult for her body to retain the heat it is generating.