Cat Man Do – Simon’s Cat.
Why Am I So Tired and Sleepy? The compound Adenosine (ah-DEN-o-seen) is one factor. Adenosine is produced in the human body by the degradation of adenosine triphosphate (ATP), the molecule that serves as the “energy currency” for the body’s various cellular functions. The amount of adenosine produced in the brain thus reflects the activity level of its neurons and glial cells. The brain’s intense activity during periods of wakefulness consumes large amounts of ATP and hence causes adenosine to accumulate.
More About Neurons
The neuron is the basic working unit of the brain, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells. Neurons are cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.
More About Glial Cells
The glial cells surround neurons and provide support for and insulation between them. Glial cells are the most abundant cell types in the central nervous system. Types of glial cells include oligodendrocytes, astrocytes, ependymal cells, Schwann cells, microglia, and satellite cells. There are about 86-100 billion neurons in the brain. There are about the same number of glial cells in the brain. The glial cells do not carry nerve impulses. There are different types of glial cells: Astrocyte, Microglia, Oligodendroglia, Satellite Cells and Schwann Cells:
Astrocyte (Astroglia): Star-shaped cells that provide physical and nutritional support for neurons: 1) clean up brain “debris”; 2) transport nutrients to neurons; 3) hold neurons in place; 4) digest parts of dead neurons; 5) regulate content of extracellular space
Microglia: Like astrocytes, microglia digest parts of dead neurons.
Oligodendroglia: Provide the insulation (myelin) to neurons in the central nervous system.
Satellite Cells: Physical support to neurons in the peripheral nervous system.
Schwann Cells: Provide the insulation (myelin) to neurons in the peripheral nervous system.
The accumulation of adenosine during waking periods is thus associated with the depletion of the ATP reserves stored as glycogen in the brain. The increased adenosine levels trigger non-REM sleep, during which the brain is less active, thus placing it in a recovery phase that is absolutely essential—among other things, to let it rebuild its stores of glycogen. Because adenosine is continuously metabolized by the enzyme adenosine desaminase, the decline in adenosine production during sleep quickly causes a general decline in adenosine concentrations in the brain, eventually producing conditions more favourable to awakening.
The human body clock is another factor.
Our bodies are in sync with environmental cues such as light and darkness to help determine when we feel awake and when we feel drowsy. This relates to when the body releases melatonin.
Melatonin is a factor.
Your body releases chemicals in a daily rhythm, which your body clock controls. When it gets dark, your body releases a hormone called melatonin. Melatonin signals your body that it’s time to prepare for sleep, and it helps you feel drowsy. The amount of melatonin in your bloodstream peaks as the evening wears on. Researchers believe this peak is an important part of preparing your body for sleep.