Cranial nerves 1 Flashcards
What are cranial nerves?
12 pairs which Link the face, head and neck to the brain
How many spinal nerves are there?
31 pairs which connect to the rest of the body to the spinal cord.
What are the 12 cranial nerves names?
|- Olfactory nerve || -Optic nerve |||- Oculomotor nerve |V - Trochlear nerve V - Trigeminal nerve V| -Abducent nerve VV||- Facial nerve V|||- Vestibulo- cochlear nerve |X- Glossopharyngeal nerve X - Vagus nerve X|- Accessory nerve X||- Hypoglossal nerve
What nerves are connected to the cerebrum?
| || - Optic nerve
- Olfactory nerve
What are the other 10 nerves connected to?
Brainstem
What are the olfactory bulbs?
collection of neurones that sit underneath the first part of your brain received direct input from receptors up your nose.
-The chemoreceptors attaché themselves to chemical receptors up your nose which are attached to axons which send info to the olfactory bulb
What is the optic nerve?
-begin with a bunch of neurones infront of the eye especially in retina.
What are the 3 main divisions of the brainstem?
- Midbrain
- Pons- bridge between midbrain and medulla
- Medulla
What is anopcia?
Damage to optic nerve
What do the prefixes a- and an- mean?
can’t (nerve damage)
What are each cranial nerve : important features?
- Number and name
- Composition- sensory, voluntary motor , autonomic
- Region/tissues supplied: sensory or motor
- Foramen, fissure or canal nerve passes through
- Function and simple tests
- Effects of nerve damage/lesions
What are all involuntary autonomic systems?
- Parasympathetic : for resting and digesting
- Increase smooth muscle contraction and glandular secretion
What are sensory nerves?
- Have receptors which are connected to an axon which sends sensory information to neurone inside CNS and the synapse activate excitatory neurones in the CNS
What are the neurones that convey sensory info from these tissue to neurone in the CNS?
- Ganglion cells- primary sensory neurones
e. g cells in retina which send info to your brain down optic nerve which are called retinal ganglion cells
What are the somatic motor neurones?
Inside CNS - that have axons which come out and send signals to directly innovate via excitatory synapses skeletal or voluntary muscles.
What are the autonomic motor neurones?
-Inside CNS- send axons out into the peripheral system but don’t directly innervate target tissue such as a smooth muscle or gland, they stop off and make synaptic contact with neurones in peripheral NS (autonomic ganglion cells)- which make synaptic contact with the target tissues they are innervating.
What are the cranial nerves composition of somatic and special senses?
- Smell (1 olfactory); vision (2 optic)
- Somatic (5 trigeminal and 9 glossopharngeal)
- Taste ( 7 facial and 9 glossopharyngeal)
- Vestibular and hiring/auditory (8 vestibular cochlear)
What are the cranial composition of motor: voluntary movements of skeletal muscles?
-Eyes (3, Oculomotor; 4, Trochlear; 6, Abducent)
-Chewing/Mastication (5, Trigeminal): Facial expression (7, Facial)
-Swallowing/Vocal apparatus (9, Glosspharyngeal, 10 Vagus)
Neck (11, Accessory): Tongue (12, Hypoglossal)
What are the cranial nerves composition of motor: autonomic/parasympathetic to smooth muscle and glands?
- Iris sphincter + ciliary (pupil constriction + accommodation = 3 Oculomotor)
- Lacrimal gland (for aqueous tear production = 7 Facial)
- Salivary glands (for digesting = 7 Facial & 9 Glosspharyngeal)
- Heart, lungs, stomach glands etc (for resting & digesting = 10 Vagus)
How do cranial nerves pass?
Each cranial nerve enters (sensory neurones) or exits (motor, autonomic neurones ) the skull through a specific hole (aka: canal, foramen, fissure). -Several small; some large (foramen magnum)
What is are the 3 pairs of spaces the skull is made from?
- 2 Anteroir fossa
- 2 Middle fossa
- 2 Posterior fossa
What is a cribriform plate?
perforated plate of bone- tiny holes
- Is part of a bone which sits behind your nose.
- Olfactory bulb sit above these tiny holes
What do these holes in the skull do (tiny holes)?
- These holes are designed are designed to take axons coming from your nose directly up to target neurones in your skull.
What is the foramen magnum?
- Big whole in skull - brainstem connects to spinal cord and big arteries come in to your skull through this too.
What is the | - Olfactory nerve?
- Purely sensory nerve
- Sense of smell
- Olfactory receptors in the nasal mucosa
What is the foramen of the |- olfactory nerve?
-Those olfactory receptors are attached to axons (olfactory filaments) which pass through cribriform plate (holes) in the ethmoid bone
What is the destination of the | - olfactory nerves?
-neurones of the olfactory bulbs are underneath the brain and then activate those neurones and those neurones send axons of their own via olfactory tracts to higher brain centres for conscious smell perception.
How can |- olfactory nerves be damaged?
- can be ruptured by head injury- (rupture olfactory filaments which means there is no longer a connection in receptors of nose to olfactory bulbs )
- causing loss of sense of smell
What is anosmia?
loss of sense of smell
What is the process of |- Olfactory nerve ( and tract )?
there is mucous membrane up your nose- have receptors for various stimuli that you may inhale up your nose which are attached to olfactory filaments
-These travel up the tiny holes in the cribriform plate- to make excitatory synaptic contact with neurones in then olfactory bulbs which send axons down olfactory tract to higher centres in the brain.
What is the 2nd cranial nerve ?
Optic nerve - ||