Functions of the Nervous System
The nervous system is a complex network that allows an organism to communicate with its environment, enabling sensory perception, motor responses, integration of information, and regulation of bodily functions.
- Sensory Components: Detect environmental stimuli via sensory receptors. Examples include visual, auditory, chemoreceptors, and somatosensory receptors.
- Motor Components: Generate movements, control cardiac and smooth muscle contractions, and regulate glandular secretions.
- Integrative Components: Receive, process, and store sensory information to orchestrate appropriate motor responses.
- The nervous system is divided into central- and peripheral- nervous system.
- Central nervous system (CNS), are the brain and spinal cord.
- Peripheral nervous system (PNS), consists of peripheral sensory receptors, nerves and ganglia.
Physiology of the Neuron
Neurons, or nerve cells, are specialized for receiving, processing, and transmitting signals.
Neuron Structure
- Cell Body (Soma): Contains the nucleus, endoplasmic reticulum, and Golgi apparatus, responsible for protein synthesis and processing.
- Dendrites: Tapering processes that receive information from other neurons via neurotransmitter receptors.
- Axon: Arises from the axon hillock, conducts action potentials to transmit information to target cells.
- Axon Hillock: Region of the cell body where the axon originates. It adjoins the spike initiation zone, where action potentials are generated.
- Myelin Sheath: Insulation that increases conduction velocity. Breaks in the sheath occur at the nodes of Ranvier.
- Presynaptic Terminals: Axon endings that release neurotransmitters into the synapse to communicate with target cells.
Spinal cord
has a segmental organization and its functions are:
- Information transmission, via afferent & efferent neurons.
- Segmental reflexes, when an afferent signal enters one segment and an efferent impulse is sent from the same segment as a response (reflex) without it reaching your brain for the person to make a voluntary decision.
- Simple motor patterns
- Final common pathway for motor responses