Development of Nervous System and Cranial Nerves

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Questions and Answers

What sensory function do the cochlear nerves perform?

Vision

Hearing (correct)

Equilibrium

Taste

Which cranial nerve is responsible for innervating the stylopharyngeus muscle?

Hypoglossal nerve (CN XII)

Facial nerve (CN VII)

Glossopharyngeal nerve (CN IX) (correct)

Vagus nerve (CN X)

What is the origin of the vestibulocochlear nerve (CN VIII)?

Pons

Medulla oblongata (correct)

Cerebellum

Midbrain

Which cranial nerve provides sensory function to the oropharynx?

Glossopharyngeal nerve (CN IX) Signup and view all the answers

What is a primary function of the vagus nerve?

Vocalization and swallowing Signup and view all the answers

The vestibular nerves primarily transmit signals related to which function?

Balance Signup and view all the answers

Which structure does the glossopharyngeal nerve exit through?

Jugular foramen Signup and view all the answers

Which cranial nerve is involved in the secretion of saliva from the parotid gland?

Glossopharyngeal nerve (CN IX) Signup and view all the answers

What is the role of cranial nerves in the peripheral nervous system?

Transmitting muscle commands and sensory information Signup and view all the answers

How many paired cranial nerves are there?

12 Signup and view all the answers

Which cranial nerve is primarily responsible for facial sensation?

Trigeminal nerve Signup and view all the answers

Which of the following cranial nerves is involved in the sense of smell?

Olfactory nerve Signup and view all the answers

Which cranial nerve is responsible for controlling most of the eye's movements?

Oculomotor nerve Signup and view all the answers

Which cranial nerve is responsible for movement of the tongue?

Hypoglossal nerve Signup and view all the answers

Which cranial nerve is involved in taste sensation from the posterior part of the tongue?

Glossopharyngeal nerve Signup and view all the answers

Which cranial nerve is purely sensory?

Olfactory nerve (CN I) Signup and view all the answers

Which cranial nerves are classified as mixed nerves?

Trigeminal (CN V) and Facial (CN VII) Signup and view all the answers

Which cranial nerve primarily controls eye movement?

Oculomotor nerve (CN III) Signup and view all the answers

Which cranial nerves have parasympathetic fibers?

Oculomotor (CN III) and Glossopharyngeal (CN IX) Signup and view all the answers

The optic nerve is responsible for which function?

Receiving signals for vision Signup and view all the answers

Which cranial nerve does not contain sensory fibers?

Abducens (CN VI) Signup and view all the answers

What is known about the origin of the olfactory nerve?

It originates in the nasal cavity. Signup and view all the answers

What is the main function of the trochlear nerve?

Controlling eye movements Signup and view all the answers

Study Notes

Development of Nervous System/ Cranial Nerve

The nervous system develops in the third week of human embryonic development.
Neuroectoderm appears and forms the neural plate.
A groove forms along the neural plate.
By week four, the neural plate folds inwards, creating the neural tube.
The neural tube is filled with cerebrospinal fluid (CSF).
The neural crest differentiates and migrates away from the neural folds.
The three germ layers are formed at gastrulation (3rd week of gestation).
- Ectoderm: Outer layer, forms skin and nervous tissue.
- Mesoderm: Middle layer, forms muscle, blood, and connective tissue.
- Endoderm: Innermost layer, forms the gut, lung, and urogenital tracts.
Neurulation is the process of folding and closure of the neural plate.
- Neural folds close, neural crest migrates away.
- Closure starts in the middle of the tube, then progresses rostrally and caudally.
Failure of neuropores to close can cause neural tube defects.
- Anterior neuropore: Anencephaly
- Posterior neuropore: Spina bifida
The spinal cord and vertebral column have the same length until the third month.
The spinal cord ends at L2 or L3 in adults while the dural sac terminates at S2.
The filum terminale is a long, thin strand that attaches the end of the dural sac to the coccyx.
Sometimes the spinal cord can be tethered to the dural sac, causing hydrocephalus (swelling of brain ventricles).
Primary brain vesicles (prosencephalon, mesencephalon, and rhombencephalon) develop at the rostral end of the neural tube.
Secondary brain vesicles (telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon) develop further.
The telencephalon differentiates into the cerebral hemispheres.
The diencephalon differentiates into the thalamus and hypothalamus.
The mesencephalon differentiates into the midbrain (colliculi).
The metencephalon differentiates into the pons and cerebellum.
The myelencephalon differentiates into the medulla.
The spinal cord also differentiates.

Cranial Nerves

Cranial nerves are 12 paired nerves in the Peripheral Nervous System (PNS).
They are responsible for sensory input and muscle commands.
There are different types of cranial nerves.
- Sensory nerves only carry sensory information.
- Motor nerves only carry motor commands.
- Mixed nerves carry both sensory and motor information.
Cranial nerves are involved in sensory and motor functions in the face and head.
Olfactory nerve (CN I) transmits smell signals.
Optic nerve (CN II) transmits vision signals.
Oculomotor nerve (CN III) controls most eye muscles and pupil constriction.
Trochlear nerve (CN IV) controls superior oblique eye muscle.
Trigeminal nerve (CN V) supplies sensory information to the face (ophthalmic, maxillary, mandibular branches), and motor to muscles of mastication.
Abducens nerve (CN VI) controls lateral rectus eye muscle.
Facial nerve (CN VII) controls facial expression, taste buds, and salivary/lacrimal glands.
Vestibulocochlear nerve (CN VIII) transmits signals for hearing and balance.
Glossopharyngeal nerve (CN IX) controls swallowing, taste, and parotid salivary glands.
Vagus nerve (CN X) controls many functions like heart rate, breathing, and digestive system.
Accessory nerve (CN XI) controls neck and shoulder muscles.
Hypoglossal nerve (CN XII) controls tongue muscles.

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Description

Explore the intricate processes involved in the development of the nervous system, starting from the third week of embryonic development. This quiz covers the formation of the neural plate, neural tube, and the roles of the three germ layers. Test your knowledge about neurulation and its significance in preventing neural tube defects.