Without the sun, the body needs external sensors to regulate its temperature.
Goose bumps, "the willies" and "chilled to the bone" are all expressions used to describe the body's response to inadequate warmth on a blustery winter night. Chills force blood to return to the heart and circulate through the limbs and back to the torso. Sensory neurons under the skin send messages to the brain regarding body temperature changes. The hypothalamus alerts the brain and activates the human thermostat to increase warming blood flow throughout the body.
Sensory Messages
Sensory receptors on the skin alert the brain to environmental temperature changes.
Sensory neuron receptors on the skin's surface transmit information to the human skeleton. This information allows the human skeleton to judge proximity, temperature, light, touch and other sensations. The largest organ in the body, the skin protects the internal organs and tissues with these receptors. When the body's temperature drops from exposure to external cold, sensory neurons transmit electrical impulses to an area deep in the brain, the hypothalamus. This ancient regulator ensures the activation of vital body functions. Body temperature maintains at approximately 98.6 degrees F.
Decreased Body Temperature
Little hairs on the surface of the skin, erector pili, stand upright when the body is cold. Goose bumps raise the hairs on the arm to add a layer of insulation for the body. Cold water produces body chills quicker than cold air. Cold and wet conditions reduce the body's temperature quickly, which can lead to hypothermia. The heart draws blood to the extremities, circulating this stock back to the torso to protect the organs. Heat loss from exposed body parts such as the head and hands reduces the body temperature quickly. Any ongoing heat loss results in significant symptoms of hypothermia such as shivering, drowsiness, shallow breathing and consequent loss of consciousness
Blood Flow
Without insulating head wear, heat escapes the body quickly.
Cold increases blood flow and heart rate. In an attempt to adapt to these temperatures, the skin receptors send requests the nervous system, which increases noradrenalin release. This chemical hormone triggers the secretion of glucose and enhances blood flow to the skeletal muscles. Rapid Increases in energy to the muscles cause them to shake. This effect increases overall body temperature, rushing warming blood circulating through the body rapidly. Noradrenalin release activates chemicals in the pituitary gland that reduce hunger, digestion, elimination and coordination, temporarily. Diverting all its heat resources, blood from the heart maintains body temperature.
The Hypothalamus
The hypothalamus, near the brain stem, is the body's system regulator.
The hypothalamus lies deep within the brain, closest to the brain stem. It is responsible for all automatic organ functions, such as heartbeat, breathing, fluid and electrolyte balance, hunger, sleep and body temperature. The skin receptors transmit a message through the nervous system to the hypothalamus. Taking control, the hypothalamus increases heartrate and blood flow, causing the shaking reaction from glucose release in the muscles. The hypothalamus monitors the basic human life functions.
Tags: blood flow, body temperature, back torso, body temperature, body temperature