E-learning 8 PNS Flashcards
what does the PNS consist of
all of the neurons carrying information to or from the CNS
what neurons carry information to the CNS
affector neurons (a-arrive)
what neurons carry information from the CNS
effector neurons (e - exit)
what 3 parts does the neuron consist of
the axon
the cell body
the dendrites
what does the axon do
carry information away from the cell body. Axons of one neuron connect with the dendrites of other neurons or with other cells at synapses
what does the cell body do
contains the nucleus and all the organelles required for metabolism
what do the dendrites do
carry information to the cell body
what do synapses occur between
neurons and target cells
what can target cells be
other neurons
muscle cells
secretory cells
Electrical transmission along axons terminates at synapses and is relayed to the next cell via what
chemical messengers (neurotransmitters)
what are the neurotransmitters stored in
vesicles
what causes the neurotransmitters to be released into the synaptic cleft and bind to receptors on the post synaptic membrane
when an action potential reached the vesicles
what does the action potential stimulate in the target cell
- a depolarisation in the post synaptic neurons
- contraction in post synaptic muscle cells
- secretion in post synaptic secretory cells
how many cervical nerve pairs are there
8
how many thoracic nerve pairs are there
12
how many lumbar nerve pairs are there
5
how many sacral nerve pairs are there
5
how many coccygeal nerves are there
1
what is the spinal cord protected by
the vertebral column (the spine)
what is the vertebral column made up of
individual vertebrae
what does each vertebra consist of
a vertebral body and a vertebral arch
together what does the vertebral body and vertebral arch form
the vertebral foramen (the opening that the spinal cord resides in)
when several vertebra are stacked, the vertebral foramen align to form what
the vertebral canal
what is the vertebral arch formed of
two pedicles
two lamina
two transverse processes
one spinous process
four articular processes
what do the intervertebral discs form
a fibrocartilaginous joint (a symphysis) between two adjacent vertebrae
what is the purpose of the fibrocartilaginous joint
to allow slight movement
to act as shock absorbers
to hold the two together
what do the discs contain
- annulus fibrosus: outer fibrous ring made up of laminae of fibrocartilage to withstand compression
- nucleus pulposus: gel like center that helos distribute pressure evenly across the disc to act as a shock absorber
- a layer of hyaline cartilage
the outer section of the spinal cord is formed of what
white matter (consist of axons of neurons that form ascending or descending pathways)
ascending pathways travel from…
the body to the brain
descending pathways travel from..
the brain to the body
the inner section of the spinal cord is formed from what
grey matter (where cells bodies of neurons are located and where synapses occur between these cell bodies)
what is a useful landmark for the anterior surface of the spinal cord
the ventral median fissure (a deep groove)
the ascending and descending tracts in the spinal cord carry what nerves
somatic nerves (voluntary nervous system)
autonomic nerves dont run within the spinal cord, they run..
alongside it
dorsal column (back)
ascending sensory neurons carrying fine touch and proprioception information from the limbs run in the dorsal columns
lateral column (side)
descending motor tracts from the cerebral cortex mostly run in the lateral column
anterolateral fasciculus (front)
ascending sensory neurons carrying pain and temperature fibres run in the anterolateral fasciculus
what type of control is the autonomic nervous system
subconscious (temperature control, secretions and gastric motility)
autonomic neurons arise from the brain and spinal cord. they have ganglia (collection of cell bodies) outside the spinal cord when their axons synapse
sympathetic or parasympathetic:
Increased heart rate and force of contraction
sympathetic
constriction of pupil
parasympathetic
contraction of airway smooth muscle
parasympathetic
Increased stomach motility and gastric secretions
parasympathetic
reduced peristalsis
sympathetic
Decreased heart rate and force of contraction
parasympathetic
Decreased gut motility
sympathetic
Relaxation of airway smooth muscle
sympathetic
Increased digestion and gut motility
parasympathetic
dilation of pupil
sympathetic
Sympathetic cell bodies are present in the…
thoracic and lumbar spinal cord
Parasympathetic neurons arise from the cranial nerves or from the…
lumbo-sacral spinal cord.
There are two types of somatic nerves:
-Spinal nerves that arise from the spinal cord
-Cranial nerves that arise directly from the brain
Dorsal (posterior) roots are usually afferent/sensory carrying information from…
the periphery to the CNS.
Ventral (anterior) roots are usually efferent/motor, carrying information from…
the CNS to the periphery in somatic motor and autonomic neurons.
Each spinal nerve supplies a distinct area of skin ________ or distinct group of muscles _________.
dermatome
myotome
cranial nerves:
CNI - olfactory nerve
sensory - smell
CNII - optic nerve
sensory - carries info from the retina
CNIII - oculomotor nerve
motor - controls movements of the eye and some control of the eyelid
also controls pupil constriction
CNIV - trochlear
motor to one muscle that moves the eye
CNV - trigeminal
sensory - senses touch from skin of face
motor - muscles of mastication
CNVI - abducent
motor to one muscle of the eye
CNVII - facial nerve
sensory - taste of anterior part of the tongue
motor - muscles of facial expression and glands that secrete saliva
CNVIII - vestibulocochlear nerve
sensory - hearing
CNIX - glossopharyngeal nerve
sensory - taste
motor - initiating the gag reflex
motor - secretomotor to on saliva gland (parotid)
CNX - vagus nerve
motor - muscles of the pharynx, larynx and palate
responsible for parasympathetic innervation of in trachea, bronchi, GI tract and cardiac muscle
sensory - afferent sensation from GI tract, heart and airways
CNXI - accessory nerve
motor - to two big muscles in the neck
CNXII - hypoglossal nerve
motor - muscles of the tongue
