Body Temperature Regulation

What are three symptoms of SAD?

-Depression -Weight gain -Fatigue

What is zeitgeher?

External stimulus that initiates or resets a biological rhythm, such as sunlight (time giver)

Where is the suprachiasmatic nucleus? What is it responsible for?

-A small group of cells located in the hypothalmus, just above where the optic nerves meet, also known as the optic chiasm -Controls the physiological functions of the body

How does the amount of melatonin in the bloodstream affect sleep?

-Sun goes down, melatonin increases and remains high through the night -Sun comes up, melatonin decreases making us wake up naturally -If you wake up before the level of melatonin in the bloodstream has decreased, it is common to still feel very sleepy

What is seasonal affective disorder (SAD)? How is sunlight involved?

-When our sleep cycle is not balanced, it can have physiological impact. A form of depression that can result when there is too little or even too much sunlight -Lack of sunlight can impact the sleep-wake cycle as well as the amount of certain hormones produced and or/released

Is someone in Alaska, California, Washington, or Florida more likely to suffer from seasonal affective disorder during the winter months? Why?

Alaska, because SAD is extremely common on nordic countries due to the lack of no light

What is the biological or circadin rhythym?

Any cycle that repeats daily (sleep and wakefulness)

What is the most comon treatment for SAD?

Light therapy, which is simply an amount of time each morning exposed to a light box

What is melatonin?

Natural ability to regulate sleeping and waking with a hormone controlling it

If you were locked in a room with the light on for a week, do you think you would be awake the entire week?

No, because biological rhythms can actually be due to internal regulating mechanisms that can be influenced by external factors

What are three functions of the human body that are controlled by biological rhythms?

Physical activity, body temperature, and digestive activity

What organs produce melatonin in the body?

Pineal gland and the skin

Explain how sunlight entering the eye causes the production and/or release of melatonin.

When light reaches the retina, the light particles stimulate neurons that convert light into an electrical pulse that travels down the optic nerve. At the optic chiasm, the impulses stimulate the cells in the suprachiasmatic nucleus to start ot stop producing/releasing melatonin