Topic_1_Part_1_Nervous_system_-_Modular

Nervous System

The system that receives information, processes it, and coordinates responses; it comprises the central and peripheral nervous systems.

Central Nervous System (CNS)

Consists of the brain and spinal cord; it controls most functions of the body and mind.

Peripheral Nervous System (PNS)

Includes all the nerves outside the CNS; carries messages to and from the CNS.

Neuron

The functional unit of the nervous system specialized for transmitting impulses.

Action Potential

A rapid reversal of membrane potential that propagates along the axon when a neuron is stimulated.

Resting Potential

The electrical potential difference across a neuron's membrane when it is not actively transmitting signals, typically around -70mV.

Synapse

The junction between the axon terminal of one neuron and the receiving cell.

Autonomic Nervous System

Regulates involuntary body functions; consists of the sympathetic and parasympathetic divisions.

Sympathetic Nervous System

Part of the autonomic nervous system that prepares the body for 'fight or flight' response.

Parasympathetic Nervous System

Part of the autonomic nervous system that promotes 'rest and digest', conserving energy and maintaining body functions.

Reflex Arc

The direct route from a sensory neuron to an interneuron and then to a motor neuron, allowing for an automatic response.

Myelin Sheath

An insulating layer surrounding axons, which increases the speed of nerve impulse transmission.

Nodes of Ranvier

Uncovered areas of the axon between myelin sheaths, facilitating rapid signal conduction.—> salatory conduction

Voltage-Gated Sodium Channels

Channels that open during action potential allowing Na+ ions to rush into the neuron.

Depolarization

The process during an action potential whereby the membrane potential becomes less negative due to Na+ influx. more Na inside,

Repolarization

The process that restores the membrane potential to its resting state after depolarization. K channels open, K ions exit the axon, bringing it back to its resting potential(-70mV)

Synaptic Cleft

The gap between the presynaptic neuron and the postsynaptic neuron where neurotransmitters are released.

Neurotransmitter

Chemical messengers that transmit signals across a synapse from one neuron to another.

Acetylcholine

A neurotransmitter involved in muscle activation and the autonomic nervous system functions.

Sensory Neuron

Neurons that carry signals from sensory receptors to the CNS.

Motor Neuron

Neurons that convey impulses from the CNS to effectors (muscles or glands).

Interneuron

Neurons located in the CNS that connect sensory and motor neurons.