PNS Flashcards
what is the PNS composed of
cranial nerves
spinal nerves
autonomic nerves
(all nerves outside of the brain)
What is an Afferent nerve
nerves that are in charge of sensory information
what are the 2 types of divisions of afferent nerves
somatic nerves- carries signals from the skin, muscle, bone, and joint receptors
Visceral sensory division- carries signals from the organs and tx in the thoracic and abdominal cavities
What is an efferent nerve
in charge of motor information
somatic motor division
Efferent nerves that carries signals from the CNS to the skeletal muscles
Visceral motor division (autonomic nervous system)
controls the part of the body we do not have conscious control over
-sympathetic division “fight or flight “
parasympathetic division back to the homeostasis
List the type of nerves in the PNS
Afferent- contain sensory fibers responsible for communicating information about stimuli.
Efferent neurons- motor fiber responsible for relaying information to the muscular system
Mixed Neurons- contain both sensory and motor fiver
cranial nerve number 1
the olfactory nerve
sensory functions include the sense of smell
cranial nerve number 2
the optic nerve
sensory functions include the sense of vision.
cranial nerve number 3
the oculomotor nerve
motor functions include moving the eyelid and eye muscles
Autonomic nervous system functions include the moving the lens and the constriction of the pupil.
cranial nerve 4
the trochlear nerve
motor functions include the eye muscles
cranial nerve 5
the trigeminal nerve sensory to touch, pain, temperature sensation in face and mouth. autonomic- chewing muscles 3 branches ophthalmic nerve maxillary nerve mandibular nerve
cranial nerve 6
the abducen nerve
moving the the eye muscles
cranial nerve 7
the facial nerve
motor- facial expressions
autonomic nervous system- functions include triggering the secretion of saliva and tears
cranial nerve 8
vestibulocochlear nerve aka auditory nerve
sensory- hearing and balance
motor functions- modifying inner ear hair cells in response to sound waves.
autonomic nervous system
vestibular nerve- carries impulses for equilibrum
cochlear- impulses for hearing
cranial nerve 9
glossopharyngeal nerve
sensory- taste sensations from the tongue and pharynx
motor- swallowing and speech production
ANS- saliva secretions
cranial nerve 10
the Vagus nerve
sensory- taste,BP, breathing and HR, and visceral sensations
motor-swallowing, coughing, and speech production
autonomic- main nerve in control of ANS, mostly parasympathetic
cranial nerve 11
Accessory Nerve
motor- swallowing and the movement of the head and shoulders
ANS- control muscles of the pharynx and larynx
cranial nerve 12
the hypoglossal
movement of the tongue
What does the ANS do ?
controls vital functions that are not under conscious control. Serves the vsicera, glands, smooth muscle and cardiac muscle
main function is to regulate homoeostasis.
what are the types of neurons in the ANS ?
Autonomic Ganglion: the point at which the neurons diverge
-preganglionic neuron-the first neuron in the pair
release acetylcholine to stimulate the postganglionic neuron.
postganglionic neuron- the second neuron in the pair that leads to the effector neuron- secretes noradrenaline
what is the principle of mass activation
Principles of mass activation- one preganglionic neuron can excite a large number of postganglionic fibers
what are the two subdivisions of the ANS?
Sympathetic nervous system- fight or flight
parasympathetic- reversing the effects of the SNS
where is the sympathetic division located
spinal nerves include thoracic (T1-T2) and lumbar (L1-2)
paravetebral gangli- located close to the vertebral column
Adrenal glands
located on tp of kidneys-contains inner medulla modified sympathetic neurons. they produce adrenaline and noreadrenaline to enhance sympathetic postglanglia activity
what are the parasympathetic nerves ?
cranial nerves 3,7,9,10
contain sacral spinal nerves S2-4
What is a cholinergic receptors
neurons that release ACh
two kinds of postsynaptic membrane that bind to ACh
Nicotinic Receptors: Occur in sympathetic & parasympathetic postganglionic neurons and motor end plates at neuromuscular junctions.
Muscarinic Receptors: Found in all effectors stimulated by the parasympathetic system.
Includes smooth muscle, cardiac muscle, & glands.
what are the adrenergic receptors
release norepinephrine (NE) make up the majority of the SNS postganglions noreepinephrine tends to linger in the synapses longer than acetylcholine
hypothalamus
: Integrates & regulates ANS function. Includes cardiac & pulmonary function, sweating, vasodilation & constriction
reticular formation
Reticular Formation: Contains centers for cardiac, respiratory, vasomotor, & gastrointestinal functions.
spina; cords
: Contains centers that regulate the excretory system, without brain involvement.
