MCAT Content / Skin System / Functions In Homeostasis And Osmoregulation

Functions in Homeostasis and Osmoregulation

Topic: Skin System

The skin helps with the homeostasis and osmoregulation of the human body.

Homeostasis refers to the relatively stable state inside the body of an animal. The goal of homeostasis is the maintenance of equilibrium around a specific value of some aspect of the body or its cells called a set point. The integumentary system functions in thermoregulation—the ability of an organism to keep its body temperature within certain boundaries—even when the surrounding temperature is very different. This process is one aspect of homeostasis: a dynamic state of stability between an animal’s internal and external environment. The skin assists in homeostasis (keeping different aspects of the body constant, e.g., temperature). It does this by reacting differently to hot and cold conditions so that the inner body temperature remains more or less constant. The process of skin-based thermoregulation occurs through several means including radiation, convection, conduction, perspiration, and arrector pili muscles.

Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body’s water content; that is it keeps the body’s fluids from becoming too dilute or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution the more water wants to go into the solution. Although the kidneys are the major osmoregulatory organ, the skin and lungs also play a role in the process. Water and electrolytes are lost through sweat glands in the skin, which helps moisturize and cool the skin surface. While perspiration is used primarily to regulate body temperature, sweat also assists the human excretory system function by removing waste.


Practice Questions

Khan Academy

MCAT Official Prep (AAMC)

Biology Question Pack, Vol. 1 Question 16

Key Points

• The skin assists in homeostasis and osmoregulation.

• Homeostasis refers to the relatively stable state inside the body of an animal. he integumentary system functions in thermoregulation.

• The skin assists in homeostasis by reacting differently to hot and cold conditions so that the inner body temperature remains more or less constant through a variety of means including radiation, convection, conduction, perspiration, and arrector pili muscles.

• Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body’s water content.

• Although the kidneys are the major osmoregulatory organ, the skin and lungs also play a role in the process.

• Water and electrolytes are lost through sweat glands in the skin, which helps moisturize and cool the skin surface. Sweat also assists the human excretory system function by removing waste.


Key Terms

Evaporation: What happens when water crosses the skin via sweat glands and then dissipates into the air; this process cools body temperature to within the body’s tolerance range.

Homeostasis: The ability of a system or living organism to adjust its internal environment to maintain a stable equilibrium; such as the ability of warm-blooded animals to maintain a constant temperature.

Thermoregulation: A process that allows your body to maintain its core internal temperature. A healthy internal body temperature falls within a narrow window.

Radiation: The emission of energy as electromagnetic waves or as moving subatomic particles.

Convection: The movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

Conduction: The process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.

Perspiration: The process of sweating.

Arrector pili muscles: Any of the small muscles attached to hair follicles in mammals; when the muscles contract they cause the hairs to stand on end.

Osmoregulation: The process by which the body regulated the osmotic pressure of any organism’s fluids in order to keep the homeostasis of the organisms’ water level constant.

Osmosis: A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

Sweat: Moisture exuded through the pores of the skin, typically in profuse quantities as a reaction to heat, physical exertion, fever, or fear.



Billing Information
We had trouble validating your card. It's possible your card provider is preventing us from charging the card. Please contact your card provider or customer support.
{{ cardForm.errors.get('number') }}
{{ registerForm.errors.get('zip') }}
{{ registerForm.errors.get('coupon') }}
Tax: {{ taxAmount(selectedPlan) | currency spark.currencySymbol }}

Total Price Including Tax: {{ priceWithTax(selectedPlan) | currency spark.currencySymbol }} / {{ selectedPlan.interval | capitalize }}