ASC 512 Nervous System

Central Nervous System (CNS)

• Comprises the brain and spinal cord

Forebrain/Midbrain

• Responsible for control of cognition, senses, and memory

Cerebellum

• Controls fine motor movements

Brain Stem (Hindbrain)

• Controls automatic functions such as respiration and connects the spinal cord to the cerebrum/cerebellum

Spinal Cord

• Carries signals to/from the brain and peripheral nerves

Brain Components

• Cerebrum: responsible for thought, memory, and sensory interpretation
• Thalamus: involved in sensory processing (except smell) and consciousness
• Cerebellum: controls fine motor movements
• Midbrain: acts as a relay between brain structures
• Pons: facilitates signals between the cerebrum and cerebellum
• Medulla: regulates automatic functions

Longitudinal Fissure

• Separates the right and left cerebral hemispheres

Right and Left Cerebral Hemispheres

• The two halves of the brain responsible for various functions

Gyri and Sulci

• Ridges or folds on the surface of the cerebral cortex
• Grooves or furrows between gyri

Olfactory Bulbs

• Structures involved in the sense of smell

Optic Chiasm

• The point at which the optic nerves cross over

Corpus Callosum

• A thick band of nerve fibers connecting the right and left cerebral hemispheres

Ventricles

• Fluid-filled cavities within the brain

Brainstem (Medulla, Pons)

• Controls automatic functions and serves as a pathway for nerve signals between the brain and spinal cord

White and Gray Matter

• White Matter: composed of nerve axons
• Gray Matter: composed of nerve bodies

Peripheral Nervous System (PNS)

• Responsible for carrying information to and from the spinal cord and the rest of the body

Nerve Types

• Sensory Neurons/Nerves: responsible for carrying sensory information
• Motor Neurons/Nerves: responsible for carrying motor information
• Autonomic Neurons/Nerves: control automatic functions
• Mixed Nerves: nerves can be bundles containing both motor and sensory neurons

Cranial Nerves

• Responsible for carrying information to/from sensory organs (e.g., eyes) and muscles of the face and neck
• CN0 (Terminal nerve): associated with the vomeronasal organ, responsible for sensory functions
• CN1 (Olfactory nerve): involved in the sense of smell (sensory function)
• CN2 (Optic nerve): responsible for vision (sensory function)
• CN3 (Oculomotor nerve): responsible for motor functions involving eye muscles
• CN4 (Trochlear nerve): responsible for motor function involving the superior oblique muscle
• CN5 (Trigeminal nerve): divided into ophthalmic (V1), maxillary (V2), and mandibular (V3) branches
• CN6 (Abducent nerve): controls the lateral rectus muscle and retractor bulbi (motor functions)
• CN7 (Facial nerve): motor functions involve facial muscles, sensory function includes taste, autonomic functions include control of salivation and lacrimation
• CN8 (Vestibulocochlear nerve): responsible for hearing and balance (sensory functions)
• CN9 (Glossopharyngeal nerve): motor functions involve the tongue and pharynx, sensory function includes taste, autonomic function includes control of salivation
• CN10 (Vagus nerve): motor functions involve the larynx and pharynx, sensory and autonomic functions extend to abdominal and thoracic organs
• CN11 (Accessory nerve): controls neck muscles
• CN12 (Hypoglossal nerve): responsible for motor functions involving the tongue

Ear Anatomy

• Pinna: visible part of the ear that collects sound
• Vertical Ear Canal: tube that directs sound waves toward the eardrum
• Horizontal Ear Canal: part of the ear canal that leads to the eardrum, producing earwax for protection
• Tympanic Membrane (Eardrum): vibrates to transmit sound
• Middle Ear: space between the eardrum and inner ear, containing tiny bones that pass sound vibrations
• Auditory Ossicles (Malleolus, Incus, Stapes): three small bones in the middle ear that transmit sound vibrations from the eardrum to the inner ear
• Inner Ear: part of the ear where sound vibrations are converted into nerve impulses
• Cochlea: spiral-shaped, fluid-filled structure in the inner ear that converts sound vibrations into electrical signals sent to the brain
• Vestibule/Semicircular Canals: structures in the inner ear responsible for balance and spatial orientation

Eye Anatomy

• Conjunctiva: thin, transparent membrane covering the surface of the eye and inner eyelids
• Cornea: transparent outer layer of the eye that covers the pupil and iris, helping to focus light
• Iris: colored part of the eye that controls the size of the pupil, regulating the amount of light that enters
• Retina: light-sensitive tissue lining the back of the eye, containing photoreceptor cells that convert light into nerve impulses
• 3rd Eyelid (Nictitating membrane): translucent membrane that helps protect the eye and keep it moist
• Medial and Lateral Canthi: corners of the eye where the upper and lower eyelids meet
• Anterior Chamber: fluid-filled space between the cornea and iris, helping to maintain the shape of the eye and provide nutrients