The human brain is made of 100 billion neurons. Each neuron has a nucleus that contains genes. Many neurons bind together to form a nerve.

Which cell relays messages from one tissue to another?

Neurons are primarily composed of this cell?

The function of sneezing is to expel mucus containing foreign particles from the nasal cavity. A person sneezes when foreign particles pass through the nasal hair which triggers the release of chemical that activates body system causing sneezing. What body part is activated?

Humans feel hungry when their empty stomachs contract and glucose levels in their body drop. Both of the situations stimulate neurons that send messages to the brain which are interpreted as hunger. What body systems are involved in this process as described?

Which system is responsible for the overall control of all the internal processes that occur in the body?

The urinary bladder is a muscular organ of the excretory system that collects urine excreted by the kidney. How does the nervous system help the urinary system in excretion?

The brain has 3 major sections that send and receive signals to control all the activities that keep a person functioning efficiently. Which major section controls breathing and heart beat?

Which 2 body systems interact and initiate movement?

The muscles in the wall of the blood vessels contract or relax to vary the blood flow. Which body system regulates the contraction and relaxation of the muscles?