The Peripheral Nervous System Flashcards
Name the three parts of a neuron
Axon, dendrite, cell body
What carries information to the cell body?
Dendrites
What carries information from the cell body?
Axon
Plaques of demyelination and axon loss throughout the central (but not peripheral) nervous system
Multiple sclerosis
What structure protects the spinal cord?
The spinal cord is protected by the bones of the spinal column, the vertebrae
At what vertebral level does the spinal cord end in adults and children?
The spinal cord ends at L1 in adults and L3 in children
What does the spinal cord consist of?
The spinal cord consists of neurons which form white matter tracts ascending to and descending from the brain, and some forming relays within the grey matter of the spinal cord
What is the vertebral canal?
The lining up of vertebral foramen (open space) in the vertebral column
Where do nerves enter the body?
Dorsal roots or dorsal horn
What is the outer section of a neuron formed from?
White matter
What is the inner section of a neuron formed from?
Grey matter
Nerves that travel to the CNS are…?
Afferent
Nerves that travel from the CNS are…?
Efferent
Subconscious control of our bodies, generally innervating smooth muscle of tissues or glands. It is involved with actions such as temperature control (via sweating and vasomotor), continence, secretions and gastric motility.
Autonomic nervous system
Difference between sympathetic and parasympathetic nervous system
In general, the sympathetic system prepares the body for intense physical activity, whilst the parasympathetic system relaxes the body and inhibits high energy functions
Which nervous system is stimulated to increase heart rate?
Sympathetic
Which nervous system is stimulated to increase salivary gland saliva secretion?
Parasympathetic
Location of sympathetic neurons and their ganglia
Thoracic or lumbar spinal cord, ganglia in chains far from target organ
Location of parasympathetic neurons and their ganglia
Cranial nerves or lumbo-sacral spinal cord, ganglia are close to target organ
What is the somatic nervous system responsible for?
The somatic nervous system is responsible for conscious control of the body and associated sensory functions
What are the four types of somatosensation?
Touch (pressure), pain (nociception), temperature (specifically changes in temperature), proprioception (location of the body in space, spacial awareness)
What do somatic efferent nerves innervate?
Somatic efferent neurons innervate skeletal muscle
What are the two types of somatic neuron?
Spinal nerves and cranial nerves
The origin of nerve signals initiating movement
(Brain) Precentral gyrus
Mediator of message from brain to skeletal muscles
(Cross Section of Spinal Cord) Corticospinal tract
The messenger cell that carries the command to contract muscles
Axon
The messenger axon cell tells muscle cells to contract at this intersection
Neuromuscular junction
Neurons from which nervous systems are carried in spinal nerves?
The spinal nerves are a part of the peripheral nervous system and carry both somatic and autonomic neurons
What is a dermatome?
Area of skin supplied by sensory afferents from one spinal nerve
What is a myotome?
A group of muscles supplied by motor efferents and sensory afferents from one spinal nerve
What is a plexus?
A network of interconnecting nerves, nerves form groupings in the plexus and leave as peripheral nerves
What are the special senses?
Taste, smell, sight, hearing and balance
List the cranial nerves
Olfactory, optic, oculomotor, trochlear, trigeminal, abducent, facial, vestibulocochlear, glossopharyngeal, vagus, accessory and hypoglossal nerves
CN I Olfactory
Special sense, afferent from nasal mucosa carries information related to smell
CN II Optic
Special sense, afferent for vision from the retina
CN III Oculomotor
Controls eye movement and pupil constriction
CN IV Trochlear
Motor to one muscle that moves eye
CN V Trigleminal
Afferent from surface of face, senses touch, motor efferent to muscles of mastication (chewing)
CV VI Abducent
Somatic: motor efferent to one muscle of the eye
CN VII Facial
Special sense: taste from tongue. Somatic: motor to muscles of facial expression. Autonomic: Motor efferent to glands in saliva secretion
CN VIII Vestibulocochlear
Special sense: hearing and balance
CN IX Glossopharyngeal
Special sense: taste. Somatic: motor efferent to swallowing and afferent sensation from external ear. Autonomic: secretomotor to one salivary gland and afferent sensation from carotid body and sinus
CN X Vagus
Somatic: motor muscles pharynx, larynx and palate. Autonomic: parasympathetic innervation of smooth muscle in trachea, bronchi, HI tract and cardiac muscle
CN XI Accessory
Somatic: motor to soft palate pharynx and to two big muscles in the neck
CN XII Hypoglossal
Somatic: motor to muscles of the tongue
