10.2 Coordination in Animals

In animals, coordination of various activities such as movement and behavioral changes is achieved through two main systems: the nervous system and hormones. These systems work together to regulate physiological functions and responses.

Influence of Hormones

Hormones are biochemical substances secreted by ductless glands (endocrine glands) and play a crucial role in coordinating activities in animals. The main functions of hormones include regulating growth, development, and physiological processes. They are often referred to as chemical messengers because they are carried by the blood from their place of origin to distant organs, where they exert their effects.

• Stimulating vs. Inhibitory Hormones: Initially, hormones were thought to only stimulate activities, but it was later discovered that some hormones also act as inhibitors. These hormones control various physiological functions in the body, and even small amounts can have significant effects.

• Long-Term Effects: Hormones have a long-term influence on the function and development of the nervous system, affecting behavior, emotions, and responses to stimuli.

• Role in Behavior: Hormones significantly impact an individual’s behavior, nature, and emotional impulses.

Hormones are secreted in response to specific needs and are regulated by the nervous system, which controls when and where the hormones act, similar to how a manager oversees workers.

Example of Pheromones:

• Pheromones are chemical signals used by animals, like ants, to communicate. When an ant finds food, it secretes a pheromone that other ants follow to the food source. Once the food is consumed, the pheromone secretion stops, signaling the other ants to stop coming. This mechanism is used in pest control, where pheromones can be utilized to attract and eliminate harmful insects without harming the environment.

Influence of the Nervous System

The nervous system plays a vital role in coordinating various activities in the body, such as walking, talking, thinking, laughing, and crying. It works closely with hormones to regulate and integrate the activities of different organs.

Key Functions of the Nervous System:

• Coordination and Integration: The nervous system coordinates the activities of various organs and physiological processes, maintaining connections between different body parts and ensuring proper functioning.

• Response to Stimuli: The nervous system allows the body to respond to both external stimuli (e.g., sound, sight, taste, touch) and internal stimuli (e.g., heat, pressure, chemicals). Sensory nerves detect these stimuli, which are then processed by the brain, and responses are sent through motor nerves to glands and muscles.

• External Stimuli: These come from the environment, such as light, sound, and touch, which are sensed by organs like the eyes, ears, skin, and tongue.

• Internal Stimuli: These originate from within the body, including factors like internal pressure or temperature changes.

• Motor and Sensory Nerves: Sensory neurons transmit impulses from the sensory organs (e.g., eyes, ears, skin) to the brain, while motor neurons carry responses from the brain to muscles and glands, coordinating body functions accordingly.

Through the coordination of the nervous system and hormones, animals can effectively respond to both internal and external stimuli, ensuring proper functioning and adaptation to the environment.