The skin plays important roles in protection, sensing stimuli, thermoregulation, and vitamin D synthesis. It is the first layer of defense to prevent dehydration, infection, and injury to the rest of the body. Sweat glands in the skin allow the skin surface to cool when the body gets overheated. Thermoregulation is also accomplished by the dilation or constriction of heat-carrying blood vessels in the skin. Immune cells present among the skin layers patrol the areas to keep them free of foreign materials. Fat stores in the hypodermis aid in both thermoregulation and protection. Finally, the skin plays a role in the synthesis of vitamin D, which is necessary for our well-being but not easily available in natural foods.
Prevents the entrance of harmful physical and chemical agents into the body
Melanin protects us from the harmful ultraviolet rays of the sun
Lipids prevent excessive water and electrolyte loss
Acidic pH of skin kills most bacteria and microorganisms that come in contact with our skin
Hair acts as an insulator, protects our eyes, and filters out foreign particles in our nose
6. Immune (dendritic) cells in skin function as innate immunity to detect foreign bodies
Receptor sites for changes in temperature (hot and cold) and pressure (pleasure and pain) are found in the skin.
Combinations of stimulations result in the sensations of itching, burning, and tickling.
Normal body temperature is regulated by blood vessel dilation and constriction in the dermis of the skin.
Sweating is an evaporation process that cools the body.
Fat stores act as energy source and for insulation.
The skin manufactures vitamin D through exposure to ultraviolet rays of the sun.
Sebum has antifungal and antibacterial properties.
Sweat contains waste products such as urea, uric acid, and ammonia, so it is also an excretion.
Meissner corpuscle
(also, tactile corpuscle) receptor in the skin that responds to light touch
Pacinian corpuscle
(also, lamellated corpuscle) receptor in the skin that responds to vibration
rickets
disease in children caused by vitamin D deficiency, which leads to the weakening of bones
vitamin D
compound that aids absorption of calcium and phosphates in the intestine to improve bone health
1. In humans, exposure of the skin to sunlight is required for ________.
A) vitamin D synthesis
B) arteriole constriction
C) folate production
D) thermoregulation
A
2. One of the functions of the integumentary system is protection. Which of the following does not directly contribute to that function?
A) stratum lucidum
B) desmosomes
C) folic acid synthesis
D) Merkel cells
C
3. An individual using a sharp knife notices a small amount of blood where he just cut himself. Which of the following layers of skin did he have to cut into in order to bleed?
A) stratum corneum
B) stratum basale
C) papillary dermis
D) stratum granulosum
C
4. As you are walking down the beach, you see a dead, dry, shriveled-up fish. Which layer of your epidermis keeps you from drying out?
A) stratum corneum
B) stratum basale
C) stratum spinosum
D) stratum granulosum
A
5. If you cut yourself and bacteria enter the wound, which of the following cells would help get rid of the bacteria?
A) Merkel cells
B) keratinocytes
C) Langerhans cells
D) melanocytes
C
1. Why do people sweat excessively when exercising outside on a hot day?
Sweating cools the body when it becomes warm. When the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate, and the sweat glands begin to secrete more sweat. The evaporation of the sweat from the surface of the skin cools the body by dissipating heat.
2. Explain your skin’s response to a drop in body core temperature.
When the core body temperature drops, the body switches to heat-conservation mode. This can include an inhibition to excessive sweating and a decrease of blood flow to the papillary layers of the skin. This reduction of blood flow helps conserve body heat.