Answer:
1. dopamine and serotonin
2. brain and spinal cord
3. controls the function of different processes in the body
4. limbic system
5. Increase brain surface area
6. release hormones into the bloodstream
7. insulation
8. laughing has multiple positive functions in the body
Explanation:
Dopamine is a neurotransmitter (i.e., a chemical messenger) involved in responses to rewards, motivation and memory, while serotonin is another neurotransmitter that controls appetite, mood, wakefulness and sleep onset. The central nervous system (CNS) consists of the brain and spinal cord. The spinal cord acts as a conduit by which messages are sent from the brain to the body and from the body to the brain. Moreover, the brain acts to control all body abilities (e.g., thinking, talk, feeling, walking, breathing, etc). The autonomic nervous system is known to modulate different processes (e.g., blood pressure, digestion, breath) and internal organs (e.g., heart) by acting largely unconsciously, i.e., without a person's conscious effort. The limbic system is a part of the brain that acts to control emotions and memory by modulating autonomic/endocrine functions. Convolutions, folds, and fissures can increase brain surface area, thereby more neurons are packed into the cortex of the brain and thus it is possible to process more information. The endocrine system acts to release hormones into the bloodstream. These hormones travel in the blood to their target cells/tissues, where they regulate different functions (e.g., mood, growth, development, metabolism, reproduction, etc). The myelin is an insulating layer surrounding nerve cells that enables electrical impulses to transmit efficiently around the whole body. Laughing has multiple positive functions: release endorphin hormones that decrease stress, increases the number of immune cells and antibodies, stimulate the activity of internal organs (e.g., heart), quickly relax the muscles, contribute to increase the oxygen uptake rate in blood, etc.
