The nervous system -notes

Central Nervous System (CNS)

brain and spinal cord.

Peripheral Nervous System (PNS)

outside of the brain and spinal cord, including nerves and ganglia.

-PNS nervous project to target organs and to muscles (efferent)

-These nerves also carry sensory information to the brain (afferent)

NS consists of :

Neurons (Cells responsible for receiving & transmitting electrochemical information) and supporting and immune cells

Neurons

Cells responsible for receiving and transmitting electrochemical information.

Can be classified as

-number of axon processes:

• multipolar: one axon, many dendritic branches

• unipolar: one stalk that splits into 2 branches

• bipolar: one axon, one dendritic tree

-Function

• sensory neurons carry messages toward brain

• motor neurons carry messages to muscles

• interneurons connect cells

Supporting cells

-Various types

-provide a wide variety of supportive functions

Multipolar Neuron

A type of neuron with one axon and many dendritic branches.

Bipolar Neuron

A type of neuron with one axon and one dendritic tree.

Unipolar Neuron

A neuron with one stalk that splits into two branches.

Astrocytes

Star-shaped supporting cells in the CNS that maintain the blood-brain barrier and regulate the chemical environment.

Oligodendrocytes

The most common glial cell type in the CNS that forms myelin sheaths around axons.

Microglia

Small immune cells in the CNS that clear away dead cells and protect against disease.

Schwann Cells

Glial cells that produce myelin sheath around PNS axons and assist in their regeneration.

Action Potential (AP)

A stereotyped change in membrane potential that propagates along neurons.

Resting Membrane Potential (RMP)

The difference in voltage between the inside and outside of a neuron at rest.

Saltatory Conduction

The process by which action potentials jump from node to node in myelinated axons.

Synapse

The junction between the terminal button of an axon and the membrane of another neuron.

Neurotransmitters

Chemicals released by terminal buttons that alter the activity in other neurons.

Reuptake

The process of transporting a neurotransmitter back into the cytoplasm of the presynaptic neuron.

Neuroplasticity

The brain's ability to reorganize and change its structure and function throughout the lifespan.

Neurogenesis

The process by which new neurons are generated.

Cerebrospinal Fluid (CSF)

A fluid that surrounds the brain and spinal cord, providing cushioning and reducing weight.

Dura Mater

The outermost layer of the meninges protecting the brain and spinal cord.

Arachnoid

The middle layer of the meninges, which overlies the arachnoid space.

Pia Mater

The innermost layer of the meninges, closely adhering to the brain.

Gyri

The bulges or ridges in the cerebral cortex.

Sulci

Small grooves on the surface of the cerebral cortex.

Fissures

Large grooves on the surface of the cerebral cortex.

Frontal Lobe

The lobe of the brain responsible for executive functions, decision-making, and motor control.

Parietal Lobe

The lobe of the brain responsible for processing sensory information.

Occipital Lobe

The lobe of the brain primarily responsible for visual processing.

Temporal Lobe

The lobe of the brain involved in auditory processing and memory.

Nerve

A collection of axons outside the central nervous system.

Tract

A collection of axons inside the central nervous system.

Nucleus

A collection of cell bodies inside the central nervous system.

Ganglion

A collection of cell bodies outside the central nervous system.

Stem Cells

Immature cells with the potential to develop into various types of cells.