Animal -Nervous System

Key Notes:

Definition of the Nervous System

• The nervous system is a complex network of cells and tissues that coordinates the actions and sensory information of an organism.

• It consists of the brain, spinal cord, and nerves.

Main Divisions

• Central Nervous System (CNS): Comprises the brain and spinal cord; responsible for processing information and controlling responses.

• Peripheral Nervous System (PNS): Includes all the nerves outside the CNS; connects the CNS to limbs and organs.

Functions of the Nervous System

• Sensory Function: Receives stimuli from internal and external environments through sensory receptors.

• Integration: Processes and interprets sensory information to determine the appropriate response.

• Motor Function: Sends signals to muscles and glands to initiate actions.

Types of Neurons

• Sensory Neurons: Transmit sensory information from receptors to the CNS.

• Motor Neurons: Carry signals from the CNS to effectors (muscles and glands).

• Interneurons: Connect sensory and motor neurons within the CNS, facilitating communication.

Structure of Neurons

• Cell Body: Contains the nucleus and organelles.

• Dendrites: Receive signals from other neurons.

• Axon: Conducts impulses away from the cell body to other neurons or muscles.

• Myelin Sheath: Insulates the axon to speed up signal transmission.

Synapses

• Junctions where neurons communicate with each other or with target cells (muscles, glands).

• Neurotransmitters are released from one neuron and bind to receptors on another, facilitating signal transmission.

Nervous System Disorders

• Common disorders include Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis.

• These conditions can affect cognitive functions, movement, and overall nervous system health.

Importance of the Nervous System

• Controls voluntary and involuntary actions.
• Enables communication between different parts of the body.

• Facilitates response to changes in the environment.

Interaction with Other Systems

• Works closely with the endocrine system to regulate bodily functions.

• Coordinates with the muscular system for movement and reaction.

Adaptation and Evolution

• Nervous systems have evolved in complexity across different animal species, reflecting adaptations to their environments and lifestyles.