The Atacama Desert: The driest desert in the world Kelsey Graczyk
The three bodily systems most affected by the Atacama Desert are:
The Integumentary System:
Made up of the skin, hair, and nails.
In the desert climate, the body brings a series of heat-losing (thermolytic) mechanisms into operation.
When the body temperature exceeds 91 degrees F., the skin starts to secrete sweat to cool off.
Lost water must be replaced in order to maintain fluid balance throughout body.
If the fluid is not replaced the body is forced to draw on its tissue reserves- leading to dehydration.
The Nervous System : - consists of the brain and the spinal cord, and the peripheral nervous system
Dehydration, or the loss of body water is from sweating, urination, vomiting, and diarrhea. The symptoms are thirst, which is the first symptom, water present in the blood, lymph, and intestinal fluid is then lost. It affects the proper functioning of the heart, central nervous system, and organs containing smooth muscle.
Hallucinations can occur in the desert during extreme fatigue, which cause the mechanism within the brain that helps to distinguish conscious perceptions from internal, memory-based perceptions to misfire.
The Cardiovascular System: -contains the heart and blood vessels.
It distributes nutrients from food throughout your body, feeding your bones, nerves, organs, and tissues in your body. With very little food in the desert, the cardiovascular system can no longer distribute nutrients and shuts down causing the heart to stop beating.
The cardiovascular system also helps stabilize body temperature and pH to maintain normal homeostasis. However, in the desert the body temperature rises dramatically and the cardiovascular system can no longer support the high temperatures, leading to death.
Location of Atacama Desert:
NE Lat/Long: S 21.14 / W 64.63 NW Lat/Long: S 20.05 / W 70.1 SW Lat/Long: S 25.87 / W 71.55 SE Lat/Long: S 26.96 / W 65.84
Google earth link
Physical Conditions: -covering a 966 km (600 mi) strip of land on the Pacific coast of South America -20 million-year-old desert is 50 times drier than California’s Death Valley. -occupies 181,300 square kilometers (70,000 mi²) in northern Chile, composed mostly of salt basins, sand, and lava flows. -virtually sterile because it is blocked from moisture on both sides by the Andes mountains and by the Chilean Costal Range. -extends from the Pacific Ocean to the Andes Mountains and in the middle of this desert, at an altitude of 7,000 feet
Homeostasis : an organism’s ability to regulate its internal environment so as to maintain a stable, constant condition.
In the desert the body is trying to maintain normal body temperature of 98 degrees F. However, with extremely high temperatures the body temperature rises dramatically causing overheating.
Our blood, is more than 83% water and flows throughout our body, distributing nutrients, oxygen, and antibodies on demand. In a desert the body loses mass amounts of water from sweat due to high temperatures. The fluid loss overwhelms the body's ability to compensate, blood pressure falls (hypotension) and a person may go into shock, in which organs in the body may not get enough oxygen to function and thus fail.
Maximum temperatures humans can endure:
108 degrees F is the maximum temperature a human can endure in the desert before they die.
When the body starts climb over 102 degrees, thermoregulation sets in which is the ability of an organism to keep its body temperature within certain boundaries, even when temperature surrounding is very different.
If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as heat stroke occurs.
Adaptations of the human body in the desert:
Physiological and Anatomical:
Sweat glands under the skin secrete sweat (a fluid containing mostly water with some dissolved ions) which travels up the sweat duct, through the sweat pore and onto the surface of the skin. This causes heat loss by evaporation; however, a lot of essential water is lost.
The hairs on the skin lie flat, preventing heat from being trapped by the layer of still air between the hairs. These flat hairs increase the flow of air next to the skin increasing heat loss by convection. When environmental temperature is above core body temperature, sweating is the only physiological way for humans to lose heat.
Arterioles Vasodilation occurs, this is the process of relaxation of smooth muscle in arteriole walls allowing increased blood flow through the artery. This redirects blood into the superficial capillaries in the skin increasing heat loss by radiation and conduction.
In the desert when temperatures reach over 100 degrees it is necessary to use as little energy as possible. One way to conserve energy is to sleep during the day and travel at night to avoid the sun.
Another adaptation is to obtain any amounts of water that can be found. One way of doing this is to find rocks where moisture is held or shade where moisture can accumulate.
-Thermoregulation. Wikipedia. 4 December 2008.
-Wong, Lena (1997). “Temperature of a Healthy Human.” The Physics Factbook . 8 December 2008.
-Davis, Nicole. "Atacama Desert, Chile," National Geographic Adventure. February 2002. 8 December 2008.