Nervous System Overview Flashcards
What are the two cells of the nervous system?
neuroglia, neurones
What are the functions of the nervous system?
communication, regulating internal events, organising behaviour (external), information storage (memory), sensations, perceptions, emotions
What is the CNS made of?
spinal cord and brain
What is the PNS made of?
cranial nerves and spinal nerves
What is the role of neuroglia cells?
supportive, nutritive role
What cell is responsible for the myelination in the PNS?
Schwann cell
What cell is responsible for the myelination in the CNS?
oligodendrocytes
What regions are white matter in the brain?
highly myelinated regions/axons
What is the role of astrocytes and where are they found?
Astrocytes are star- shaped cells with projections that anchor to capillaries. They form the blood brain barrier, which isolates the CNS from the general circulation. They provide nutrients to neurons in the CNS
What is the role of microglia and where are they found?
Microglia are phago-cytes that move through nervous tissue removing unwanted substances. Remove cell debris, wastes, and pathogens by phagocytosis. Found in the CNS
What is the role of ependymal cells and where are they found?
Ependymal cells are simple cuboidal epithelial cells that line fluid-filled passageways within the brain and spinal cord. Assist in producing, circulating, and monitoring cerebrospinal fluid. Found in CNS
What is the role of oligodendrocytes and where are they found?
Oligodendrocytes are cells with sheet-like processes that wrap around axons. Myelinate CNS axons; provide structural framework. Found in the CNS
What is the role of Schwann cells and where are they found?
Surround all axons in PNS; responsible for myelination of peripheral axons; participate in repair process after injury
What is the role of satellite cells and where are they found?
Surround neuron cell bodies in ganglia; regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in ganglia. Found in the PNS
What are the systems of the PNS?
somatic (SNS) - conscious
autonomic (ANS) -non conscious
How many spinal nerves are there?
31 pairs
What does each spinal nerve contain?
many sensory and motor axons
What is the difference between motor and sensory neurons?
the main function of Sensory Neurons is to send sensory signals from sensory organs to the central nervous system. Motor Nerves are responsible for sending motor commands from the central nervous system to the sensory organs to initiate actions.
What is a dermatome?
regions of body surface that sensory neurons supply structure
What is a myotome?
region of muscle supplied by motor axon
Why are dermatomes important?
Dermatomes are clinically important because damage or infection of a spinal nerve or spinal ganglion produces a loss of sensation in the corresponding region of the skin
What are nerve plexuses?
peripheral neurons that supply particular regions of the body
How many cranial nerves?
12 pairs
Where are cranial nerves especially connected in the brain?
brainstem
What are important cranial nerves in the oral cavity?
- (5)Trigeminal nerve: translates sensory information in the upper and middle face and controls motion in the jaw and ear
- (7)Facial nerve: controls cranial nerves in the face that govern facial expression and taste
- (9)Glossopharyngeal nerve: controls sensory information in the back of the tongue and muscle movement in the back of the throat
- (12)Hypoglossal nerve: controls nerves in the mouth, particularly concerning tongue movement
Describe A delta nerve axons
myelinated however has a small diameter. found in sensory neurones
Describe A beta nerve axons
myelinated with a large diameter. found in sensory neurones
Describe C nerve axons
unmyelinated, not required to be fast. found in sensory neurones and some autonomic nerves
What is afferent?
neurons going towards the CNS (arrival)
not all sensorial afferents will reach the brain - action can occur before (reflex)
What is efferent?
neurons going away from CNS (exit)
What are the spinal nerves and how many of each?
cervical (8)
thorax (12)
lumbar (5)
sacral (5)
coccygeal (1)
What are cranial nerves 1-6?
Olfactory (1)
Optic (2)
Oculomotor (3)
Trochlear (4)
Trigeminal (5)
Abducens (6)
What does the olfactory (I) nerve control?
carries special sensory information responsible for the sense of smell
What does the optic nerve control?
carry visual information from special sensory ganglia in the eyes
What does the oculomotor nerve control?
Muscle function. Your oculomotor nerve provides motor function to four of the six muscles around your eyes. These muscles help your eyes move and focus on objects.
Pupil response. It also helps to control the size of your pupil as it responds to light.
What does the trochlear nerve control?
trochlear nerve controls your superior oblique muscle. This is the muscle that’s in charge of downward, outward, and inward eye movements.
What does the trigeminal nerve control?
controls face, jaw and ear muscles
has 3 divisions
Ophthalmic nerve (V1) (sensory): orbital structures, cornea, nasal cavity, skin of forehead, upper eyelid, eye- brow, nose (part).
Maxillary nerve (V2) (sensory): lower eyelid, upper lip, gums, and teeth; cheek; nose, palate, and pharynx (part).
Mandibular nerve (V3) (mixed): sensory from lower gums, teeth, and lips; palate and tongue (part); motor from motor nuclei of pons
What does the abducens nerve control?
motor eye movement of lateral rectus, the sixth pair of extrinsic eye muscles.
What are the cranial nerves 7-12?
facial nerve (7)
vestibulocochlear nerve (8)
glossopharyngeal nerve (9)
vagus nerve (10)
accessory nerve (11)
hypoglossal nerve (12)
What does the facial nerve control?
taste for front 2/3 of tongue (sensory)
movement of facial expression muscles
supplies glands
temporal, zygomatic, buccal, marginal mandibular, and cervical branches
What does the vestibulocochlear nerve control?
controls special sensory: balance and equilibrium (vestibular nerve)
(sensory) hearing (cochlear nerve)
What does the glossopharyngeal nerve control?
both motor and sensory functions, including:
sending sensory information from your sinuses, the back of your throat, parts of your inner ear, and the back part of tongue
providing a sense of taste for the back 1/3 tongue
stimulating voluntary movement of a muscle in the back of your throat called the stylopharyngeus
What does the vagus nerve control?
both sensory and motor functions, including:
conveying sensation information from your ear canal and parts of your throat
sending sensory information from organs in your chest and trunk, such as your heart and intestines
allowing motor control of muscles in your throat
stimulating the muscles of organs in your chest and trunk, including those that move food through your digestive tract
providing a sense of taste near the root of your tongue
What does the accessory nerve control?
motor nerve that controls the muscles in your neck. These muscles allow you to rotate, flex, and extend your neck and shoulders.
What does the hypoglossal nerve control?
motor movement of tongue muscles
Describe neurones in the somatic nervous system
myelinated and singular
What transmitter works in the SNS?
acetylcholine
Describe neurones in the autonomic nervous system
non-myelinated/ lightly myelinated and two neurones (preganglionic and postganglionic)
What transmitters work in the ANS?
acetylcholine, noradrenaline
What muscle does the SNS effect?
skeletal
What muscles does the ANs effect?
cardiac, smooth
