Brain

Definition

The brain is the central organ of the nervous system, responsible for processing sensory information, coordinating movement, and enabling cognition, emotions, and behavior. It plays a critical role in interorgan metabolism by integrating signals from various organs to maintain homeostasis and respond to metabolic needs.

5 Must Know Facts For Your Next Test

1. The brain consumes about 20% of the body's total energy expenditure despite representing only about 2% of body weight.
2. Neurons in the brain communicate with each other through synapses using neurotransmitters, which can influence metabolic pathways in other organs.
3. The brain regulates hunger and satiety through pathways that involve hormones like leptin and ghrelin, which are produced by adipose tissue and the stomach respectively.
4. In response to fasting or low energy availability, the brain can signal other organs to initiate gluconeogenesis or mobilize fatty acids for energy.
5. The brain is highly adaptive and can change its structure and function in response to new experiences or metabolic demands, a phenomenon known as neuroplasticity.

Review Questions

• How does the brain interact with other organs to maintain metabolic balance?
  • The brain interacts with various organs through signaling pathways that regulate metabolism. For instance, it receives information about nutrient levels from the blood and can adjust hormonal secretions from glands like the pancreas to control glucose levels. Additionally, the hypothalamus plays a crucial role by integrating signals from peripheral organs such as adipose tissue and the liver to ensure that energy supply meets demand.
• Discuss the role of neurotransmitters in mediating communication between the brain and peripheral tissues in metabolic processes.
  • Neurotransmitters are vital for communication between the brain and peripheral tissues. For example, neurotransmitters like dopamine and serotonin can influence appetite and energy expenditure. When the brain detects changes in metabolic status, it releases specific neurotransmitters that can alter hormone levels from endocrine glands, thereby affecting how other organs respond to energy availability.
• Evaluate the impact of impaired brain function on interorgan metabolism and overall homeostasis.
  • Impaired brain function can significantly disrupt interorgan metabolism and overall homeostasis. Conditions such as neurodegenerative diseases can lead to altered signaling pathways that impact appetite regulation and energy balance. This disruption may cause metabolic disorders like obesity or diabetes as the brain fails to appropriately coordinate responses among organs like the liver, pancreas, and adipose tissue, leading to an inability to maintain stable blood glucose levels or body weight.

Related terms

Hypothalamus: A region of the brain that links the nervous system to the endocrine system via the pituitary gland and plays a key role in regulating metabolic processes, body temperature, and hunger.

Neurotransmitters: Chemical messengers that transmit signals across synapses between neurons in the brain and play essential roles in regulating mood, cognition, and metabolic processes.

Blood-brain barrier: A selective permeability barrier formed by endothelial cells in brain capillaries that protects the brain from harmful substances while allowing essential nutrients to pass through.