Nervous System Overview

Study Notes

The nervous system controls all body activities, faster than other systems like the endocrine system.
It's divided into two main parts: Central Nervous System (CNS) and Peripheral Nervous System (PNS).

The CNS includes the brain and spinal cord, which are formed by neurons and neuroglia.
The brain is housed in the skull, continuous with the spinal cord via the foramen magnum.
The spinal cord runs through the vertebral canal.
The spinal cord and brain are surrounded by three layers of meninges: dura mater, arachnoid mater, and pia mater.
The space between arachnoid and pia mater is the subarachnoid space, filled with cerebrospinal fluid.

The brain is divided into different regions, each with specific functions.
The forebrain (prosencephalon) has the telencephalon (cerebral hemispheres, basal ganglia, hippocampus, amygdala) and diencephalon (thalamus, hypothalamus, metathalamus, subthalamus).
The midbrain (mesencephalon) is a part of the brainstem.
The hindbrain (rhombencephalon) has the metencephalon (pons, cerebellum) and myelencephalon (medulla oblongata).

The brainstem connects the brain to the spinal cord, regulating basic life functions like breathing and heart rate.
The midbrain is responsible for visual and auditory processing, and motor movement
The pons aids in regulating breathing and communication between brain parts.
The medulla oblongata controls autonomic functions like heart rate, blood pressure, and digestion.
The thalamus is a sensory relay station, directing information to the cerebral cortex.
The hypothalamus regulates bodily functions (e.g. hunger, thirst, body temperature, sleep) and connects the nervous system to the endocrine system.
The spinal cord connects the brain to the PNS and coordinates reflexes through spinal reflex arcs to allow fast reactions without direct brain involvement.
It contains the different spinal cord segments, such as cervical, thoracic, lumbar, sacral, and coccygeal.

The PNS connects the CNS to limbs and organs, enabling communication between them.
It has two main subdivisions: Somatic and Autonomic Nervous Systems.

The somatic nervous system controls voluntary movements and transmits sensory information.
Sensory (afferent) neurons carry information from sensory organs like skin, eyes, and ears to the CNS, allowing perception of stimuli.
Motor (efferent) neurons transmit signals from the CNS to skeletal muscles, enabling voluntary movement.

The ANS regulates involuntary functions like heart rate, digestion, and respiration.
It has two further subdivisions: Sympathetic and Parasympathetic Nervous Systems.
Sympathetic Nervous System: Activates "fight-or-flight" response during stressful situations
Parasympathetic Nervous System: Activates "rest-and-digest" response for relaxation
Enteric Nervous System (ENS): controls gastrointestinal functions, mostly independently of the brain.

Cranial nerves are a set of twelve paired nerves originating from the brain, primarily serving the head and neck.
Each cranial nerve has unique functions (sensory, motor, or mixed).
The presentation describes specific cranial nerves (I-XII) and their functions and pathways.
Olfactory (smell)
Optic (vision)
Oculomotor (eye movements, pupil constriction)
Trochlear (eye movement)
Trigeminal (face sensation, chewing)
Abducens (eye movement)
Facial (facial expression, taste)
Vestibulocochlear (hearing, balance)
Glossopharyngeal (taste, swallowing)
Vagus (voice, swallowing, regulating internal organs)
Accessory (shoulder movement, head rotation)
Hypoglossal (tongue movement).