Untitled Quiz

Study Notes

The nervous system is a complex network of billions of neurons and neuroglia.
It is responsible for communication and control throughout the body.
The nervous system is divided into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
Neurology specializes in the study and treatment of nervous system disorders.

The central nervous system is the body's control center.
It consists of the brain and the spinal cord.
Brain components:
- Cerebrum
- Brainstem
- Cerebellum
Spinal Cord components:
- Cervical cord
- Thoracic cord
- Lumbar cord
- Sacrococcygeal cord

The peripheral nervous system connects the CNS to the rest of the body.
It consists of:
- Spinal nerves (31 pairs)
- Cranial nerves (12 pairs)
- Peripheral nerves
- Autonomic nerves

Neurons are the functional units of the nervous system.
They are specialized cells that transmit information via electrical impulses.
- Cell body/ Soma: Contains the organelles, processes and interprets messages.
- Dendrites: Receive stimuli and transmit information towards the cell body.
- Axon: Transmits information away from the cell body, often much longer than dendrites, covered by the axolemma.
- Axon terminal: The distal end of the axon that transmits the impulse to another neuron or effector organ.

The myelin sheath is a lipid-rich insulating material covering the axon.
- It increases the speed of electrical impulse transmission.
It is produced by Schwann cells in the PNS and oligodendrocytes in the CNS.
Nodes of Ranvier: Gaps between myelin sheaths that allow for saltatory conduction. This allows for the impulse to skip across the myelin sheath, increasing conduction speed.

Sensory (afferent) neurons: Conduct impulses from receptors to the CNS.
Association or Interneurons: Relay information between sensory and motor neurons.
Motor (efferent) neurons: Convey motor impulses from the CNS to effectors.

Support and protect neurons.
They're found in both the CNS and the PNS.
CNS:
- Astrocytes: Provide structure and metabolic support, regulate electrolyte balance, form the blood-brain barrier (BBB), and repair damaged neural tissue.
- Oligodendrocytes: Produce myelin in the CNS.
- Microglia: Phagocytic cells, part of the nervous system's defense against infection or injury.
- Ependymal cells: Line the ventricles of the brain and spinal cord, producing cerebrospinal fluid (CSF).
PNS:
- Schwann cells/ Neurolemnocytes: Produce myelin in the PNS.
- Satellite cells: Support and protect peripheral neurons.

White matter: Represents the axons of neurons, primarily myelin.
Gray matter: Represents the cell bodies of neurons arranged in a layered manner.

Peripheral nerves are composed of:
- Epineurium: Outermost layer.
- Perineurium: Covers fascicles.
- Endoneurium: Covers individual nerve fibers.

Synapses are communication points between neurons.
They allow for the transfer of information from one neuron to another.
The most common type of synapse is the axodendritic synapse, which occurs between the axon terminal of one neuron and the dendrite of another.
Synapses: communication between neurons, usually occurs from the axon terminal of the transmitting neurons to the receptive region of the receiving neuron.