Directions: In the following table, list all of the cranial nerves in order, usi
ID: 94843 • Letter: D
Question
Directions: In the following table, list all of the cranial nerves in order, using proper numbering and names. State what part of the CNS they emerge from (forebrain, midbrain, pons, or medulla). State whether each is sensory, motor, or both. Name their function. Use proper spelling.
Nerve #
Nerve Name
Emerges from:
Sens/Mot or Both
From rostral to caudal order, name the structures and junctions that make up the brainstem.
In the adult brain, which three of five brain vesicles form the brainstem?
What are the cerebellar peduncles and where are they located?
The cranial nerve nuclei for motor functions are located more ventrally in the brainstem, and those for sensory functions are located more dorsally. True or false? _______________
Where is the pyramidal decussation?
Nerve #
Nerve Name
Emerges from:
Sens/Mot or Both
Explanation / Answer
Nerve
Nerve Name
Emerges from (originates from)
Sensory/Motor/Both
Function
0
Terminal
Lamina terminalis
Sensory
Terminal nerve is involved in the detection of pheromones.
I
Olfactory
Telencephalon
Sensory
Transmits the sense of smell from the nasal cavity.
II
Optic
Retinal ganglion cells
Sensory
Transmits visual signals from the retina of the eye to the brain
III
Occulomotor
Anterior aspect of Midbrain
Motor
Moves the eyeball and eyelid, adjusts the lens of the eye for near vision and also constricts the pupil of the eye via motor fibres distributed to muscles located in and around the eye
IV
Trochlear
Dorsal aspect of Midbrain
Motor
Moves the eyeballs by sending nerve impulses to the superior oblique muscles which are among the group of muscles that rotate the eyeballs in their sockets.
V
Trigeminal
Pons
Both
Largest cranial nerve and splits into the following 3 divisions viz; Ophthalmic nerve, Maxillary nerve and Mandibular nerve. The motor fibres of all 3 divisions control the facial muscles involved in chewing. The sensory fibres convey sensations of touch, pain and temperature from the front of the head including the mouth and also from the meninges.
VI
Abducens
Pons
Motor
Moves the eyeballs outwards by sending nerve impulses to the lateral rectus muscles.
VII
Facial
Pons
Both
Sensory fibres are concerned with taste via the taste buds at the front of the tongue.
Motor fibres control secretion of tears via the lacrimal glands and saliva via the sublingual salivary glandsas well as facial expressions via some of the muscles of facial expression.
A branch of the facial nerve regulates the tension on the ear ossicles
VIII
Vestibulocochlear
Lateral to CN VII
Sensory
2 branches
Aids equilibrium by carrying impulses from the semicircular canals - providing info about posture, movement and balance.
2. Cochlear nerve:
Carries impulses from the cochlea, so is known as the nerve of hearing.
IX
Glossopharyngeal
Medulla
Both
Motor Fibres:-
Sensory Fibres
X
Vagus
Posterolateral sulcus of Medulla
Both
Motor Fibres:
Under conscious control Stimulates voluntary muscles that effect swallowing, coughing and speech.
Under unconscious control
Stimulates the contraction and relaxation of smooth muscle in the gastrointestinal tract. Can trigger reduction (slowing) of heart-rate.
Stimulates secretion of digestive fluids
Sensory Fibres:
Monitors blood pressure
Monitors levels of oxygen and carbon dioxide in blood
Sensations of touch, pain and temperature from that area
Sensations from visceral organs in thorax and abdomen
XI
Accessory
Cranial and Spinal Roots
Motor
Arises from two roots, cranial and spinal.
Cranial parts: Controls swallowing movements because nerve fibres
Spinal Parts: Governs movement of the head and shoulders by supplying the sternocleidomastoid and trapezius muscles in the (anterior and posterior) regions of the neck.
XII
Hypoglossal
Medulla
Motor
Supplies the muscles of the tongue - responsible for the tongue movements involved in speech and swallowing
Question:- Name the structures and junctions that make up the brainstem.
Answer:- The brain stem includes the (1) medulla, (2) pons and (3) midbrain. The diencephalon, the caudal part of the forebrain, is included
The medulla, or myelencephalon, is located between the pons and spinal cord. At its caudal end, it is continuous with the spinal cord. At its rostral end, the medulla is continuous with the pons.
The pons lies between the medulla oblongata and the midbrain. It contains tracts that carry signals from the cerebrum to the medulla and to the cerebellum and also tracts that carry sensory signals to the thalamus. The pons is connected to the cerebellum by the cerebellar peduncles.
The midbrain is divided into three parts.
The first is the tectum. The tectum comprises the paired structure of the superior and inferior colliculi. Superior to the inferior colliculus, the superior colliculus marks the rostral midbrain.
The second part is the tegmentum which forms the floor of the midbrain, and is ventral to the cerebral aqueduct. Several nuclei, tracts, and the reticular formation are present in this region.
The third part, the ventral tegmentum is composed of paired cerebral peduncles. These transmit axons of upper motor neurons.
Question:- 3 of 5 brain vesicles of brainstem
Answer:- Brainstem comprises majorly of diencephalon, mesencephalon, pons of the metencephalon, and myelencephalon.
Question:- Location of cerebellar peduncles
Answer:- Cerebellar peduncles connect cerebellum to brainstem. It is a nerve tract that permits communication between the cerebellum and the other parts of the central nervous system. Three pairs of cerebellar peduncles conduct this communication. The inferior peduncles bring sensory information about the actual position of body parts such as limbs and joints. The middle peduncles transmit information about the desired position of these parts. After integrating and analysing the information from these two sources, the cerebellum sends impulses through the superior peduncles to the midbrain.
Question:- The cranial nerve nuclei for motor functions are located more ventrally in the brainstem, and those for sensory functions are located more dorsally- True or false
Answer:- False. The 12 cranial nerves can be divided into sensory, motor, or mixed nerves. Overall, sensory nerve nuclei tend to be located in the lateral brainstem, while motor nuclei tend to be located medially.
Question:- Where is pyramidal decussation?
Answer:- Pyramidal decussation is located at lower border region of medulla oblongata.
Nerve
Nerve Name
Emerges from (originates from)
Sensory/Motor/Both
Function
0
Terminal
Lamina terminalis
Sensory
Terminal nerve is involved in the detection of pheromones.
I
Olfactory
Telencephalon
Sensory
Transmits the sense of smell from the nasal cavity.
II
Optic
Retinal ganglion cells
Sensory
Transmits visual signals from the retina of the eye to the brain
III
Occulomotor
Anterior aspect of Midbrain
Motor
Moves the eyeball and eyelid, adjusts the lens of the eye for near vision and also constricts the pupil of the eye via motor fibres distributed to muscles located in and around the eye
IV
Trochlear
Dorsal aspect of Midbrain
Motor
Moves the eyeballs by sending nerve impulses to the superior oblique muscles which are among the group of muscles that rotate the eyeballs in their sockets.
V
Trigeminal
Pons
Both
Largest cranial nerve and splits into the following 3 divisions viz; Ophthalmic nerve, Maxillary nerve and Mandibular nerve. The motor fibres of all 3 divisions control the facial muscles involved in chewing. The sensory fibres convey sensations of touch, pain and temperature from the front of the head including the mouth and also from the meninges.
VI
Abducens
Pons
Motor
Moves the eyeballs outwards by sending nerve impulses to the lateral rectus muscles.
VII
Facial
Pons
Both
Sensory fibres are concerned with taste via the taste buds at the front of the tongue.
Motor fibres control secretion of tears via the lacrimal glands and saliva via the sublingual salivary glandsas well as facial expressions via some of the muscles of facial expression.
A branch of the facial nerve regulates the tension on the ear ossicles
VIII
Vestibulocochlear
Lateral to CN VII
Sensory
2 branches
- Vestibular nerve:
Aids equilibrium by carrying impulses from the semicircular canals - providing info about posture, movement and balance.
2. Cochlear nerve:
Carries impulses from the cochlea, so is known as the nerve of hearing.
IX
Glossopharyngeal
Medulla
Both
Motor Fibres:-
- Modulate swallowing via supply to muscles of the throat (pharynx) area
- Parasympathetic control of secretion of saliva (via supply to the parotid salivary glands)
Sensory Fibres
- Monitors blood pressure
- Monitors levels of oxygen and carbon dioxide in blood
- Coordination of some muscle activity e.g. in some swallowing muscles
- Sensations of taste, touch, pain and temperature from posterior third of the tongue and tissues of the soft palate
X
Vagus
Posterolateral sulcus of Medulla
Both
Motor Fibres:
Under conscious control Stimulates voluntary muscles that effect swallowing, coughing and speech.
Under unconscious control
Stimulates the contraction and relaxation of smooth muscle in the gastrointestinal tract. Can trigger reduction (slowing) of heart-rate.
Stimulates secretion of digestive fluids
Sensory Fibres:
Monitors blood pressure
Monitors levels of oxygen and carbon dioxide in blood
Sensations of touch, pain and temperature from that area
Sensations from visceral organs in thorax and abdomen
XI
Accessory
Cranial and Spinal Roots
Motor
Arises from two roots, cranial and spinal.
Cranial parts: Controls swallowing movements because nerve fibres
Spinal Parts: Governs movement of the head and shoulders by supplying the sternocleidomastoid and trapezius muscles in the (anterior and posterior) regions of the neck.
XII
Hypoglossal
Medulla
Motor
Supplies the muscles of the tongue - responsible for the tongue movements involved in speech and swallowing
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