Module 4- Nervous System

Central Nervous System

Brain cord & spine

Peripheral Nervous System

Cranial nerves and associated sensory ganglia. Spinal nerves, dorsal root ganglia and autonomic ganglia.

Autonomic nervous system

Apart of PNS. Controls internal and other self regulated body functions. Includes sympathetic (arousing) and parasympathetic (calming)

Somatic Nervous system

Part of PNS. Communicates with sense organs and voluntary muscles, includes sensory (afferent) and motor (efferent)

Cell

Basic functioning unit

Three times of neurons

Sensory, internuncial and motor

Cranial Nerves

12 pairs. Peripheral nervous system. Connects brain directly to sensory organs.

Spinal nerves

31 pairs. Peripheral nervous system. Acts as: motor nerves to permit movement and sensory to perceive stimuli.

Cerebral Lobe

Split in 4 lobes. Frontal, parietal, temporal and occipital

Frontal lobe

Front of brain, responsible for decision making and voluntary movement

Occipital lobe

Bottom back part of brain, where visual cortex is.

Pons

Located above medulla; regulates breathing and is responsible for chewing, tasting and secretion of saliva.

Midbrain

Located superior to the pons. Controls reflex movement and pupil dilation.

Medulla oblongata

Lowest part of brain that connects brain to spine. Responsible for controlling vital autonomic and reflex functions essential for survival. Ex, heart rate, BP and breathing

3 meninges

Pia Mater, arachnoid, dura mater

Pia mater

Inner layer of meninges that contains nerve tissue

Arachnoid

Middle layer of meninges made of delicate, lace like membrane

Dura mater

Outer layer of meninges that protects CNS from damage from contact with bony surface like skull and spine

Cerebrospinal Fluid (CSF)

Acts as watery cushion or shock absorber to protect CNS. Transport nutrients (mostly protein and carbs) to brain and spinal cord. Formed continuously within the ventricles of the brain at a rate of 450 mL a day.

Synapse

A specialized junction between two neurons or neuron and muscle / gland, that allows an electrical impulse pass from one cell to the next

Olfactory nerve

1st cranial nerve (CN1) - responsible for sense of smell

Palpation

Clinical examination technique where a healthcare provider uses their hands or fingertips to touch and feel a patients body

Percussion

Physical exam technique that involves tapping the surface of the body with fingers, hands or small hammer to creative vibration and audible sounds to assess organs, detect fluid or air, or airway clearance. Determines density, size and position of underlying organs.

Auscultation

Medical practice of listening to internal body sounds - such as heart, lungs, and GI tract with stethoscope

Inspection

Visual examination of patients body, skin and specific features.

Dx in children’s ears

Otitis Externa - inflection of external auditory canal that causes pain and hearing loss

Otitis media - Infection of the middle ear often associated with respiratory infections

Ear irrigation

Clears out ear wax. May be needed prior to procedures

Audiometry

Noninvasive diagnostic test that measures a persons ability to hear sounds by evaluating loudness and pitch

Tympanometry

Quick, painless test that evaluates middle ear function. Not direct hearing test, measures how well sound energy travels through middle ear.

Tuning fork exams

Rinne & Weber tests

Rinne: bed side heating test that composes air conduction to bone conduction using 512hz

Weber: quick screening that uses tuning fork to determine if a person has unilateral conductive or sensorineural hearing loss

Myopia

Nearsighted. Common refractive error where close up objects appear clear, but distant look blurry. (Opposite of hyperopia)

Primary cause is shape of eye. Typically eye is larger or longer in its axial length (front of cornia to retina). Cornea may be steeper than normal or eye itself may be larger than normal.

Ptosis

Term for droopy eyelid caused by weakness, stretching or nerve dysfunction of the muscle reasonable for lifting the eyelid

Can be dude to congenital condition or result of aging, presence of excess fatty gold, or neurological factor

Outer ear

Vibrations picked up by the pinna of the outward and directed down the external auditory canal to the ear drum (tympanic membrane)

• pinna (auricle) visible skin and cartilage structure that catches and guides sound wave

• External auditory canal: tube that leads from outside the eardrum and produces earwax

• Tympanic membrane (eardrum): thin tissue sheet that moves back and forth when sound waves hit, marking boundary of middle ear

Middle ear

Sound waves vibrate the membrane and the malleus attached to the inner surface. The malleus then “strikes” the incus, which moves the stapes.

These 3 small bones and surrounding area is the middle ear. It communicates vibrations to the inner ear by stapes pushing against the fluid in the vestibule of the inner ear through the oval window.

Middle is ear is connected by means of the Eustachian tub to the throat. The tube equalizes air pressure in middle ear.

• auditory ossicles: 3 small bones - malleus (hammer), incus (anvil), and stapes (stirrup)- that link eardrum to inner ear and boost sound force

• Eustachian tube: small passage that links middle ear to back of the nose to balance air pressure

• Tympanic cavity: air filled space that holds ossicles and proactive muscles like tensor tympani and stapedius

Otitis media

Group of inflammatory diseases and infections affecting the middle ear space just behind the eardrum