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Flashcards in Chapter 4 Deck (48):

What fibres does the ventral and dorsal root carry?

The dorsal roots carry sensory fibres and ventral roots carry motor fibres.


What is the developing ventral and dorsal horn?

The developing ventral horn is called the basal plate and the dorsal horn is called the alar plate,


What is the difference between the nerves that emerge from the brainstem and the spinal cord?

The spinal cord nerves contains both components- motor and sensory. Meanwhile, the cranial nerves sometimes are both sensory and motor, only sensory or only motor.


What is the somatic autonomic system?

The somatic system controls the voluntary muscles and receives sensations from the skin.


What is the autonomic nervous system?

The autonomic nervous system controls the visceral organs, blood vessel and receives visceral sensations.


What is sympathetic and parasympathetic system?

They both are part of the autonomic motor system. The parasympathetic nervous system is responsible for controlling the visceral organs for maintains and doing normal processes. The sympathetic nervous system is responsible for the body to ready up for a flight or fight response.


Where is the visceral motor and visceral sensory found in the spinal cord?

The visceral parts are located to medial to the somatic part.


What are the remnants of the gills in humans?

The first arch forms the jaw and the chewing muscles. The second arch forms the muscles of the facial expressions and the bone at the base of the tongue(hyoid bone). The arches 3-6 forms the bones and muscles of the pharynx and larynx.


What refers to the term somatic?

Somatic is a term referring to the skin, muscles and skeleton.


What does the term visceral refer to?

Internal organs, blood vessels, and glands.


How many spinal nerves are there?

8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal.


How long does the spinal cord extend to

The spinal cord only extends to L1-L2 because the vertebral column grows faster than the spinal cord.


What does the spinal cord form below L1 or L2?

A bundle of the remaining nerve fibres and the meninges called the cauda equina


How many rootlets form the dorsal and ventral roots?

Around 6-12


Who discovered that the ventral roots carried motor fibres and the dorsal roots carried the sensory fibres?

Magendie discovered this almost 200 years ago.


How does the spinal nerve travel?

It exits through the foramina and follow along the rib and supplies the overlying skin and muscles.


What is the area of skin supplied by a single spinal nerve called?

A dermatome.


How was dermatomes studied and mapped?

By the inspection of 100 or more patients with shingles or herpes zoster as these viruses only affects a single dorsal root ganglion. Therefore, painful vesicles appear in only a single dermatome.


Why are dermatome maps useful?

Dermatome maps are useful to determine the location of the pathology and to determine which nerve(s) is or are affected.


Are the dermatomes distorted? If so where?

The dermatomes are distorted in the limbs due to the elongation.


What are the spinal nerves that supply the limbs?

Upper limb-> C5 to T1
Lower limb-> L2 to S1


How are the upper limb neurons re arranged?

They are rearranged in a plexus to combine into three nerves- radial, ulnar and median.


How are the lower limb neurons re arranged?

The lower limb nerves are rearranged in a plexus to form three nerves- femoral, obturator and sciatic.


Which is the biggest nerve in the body and why?

The sciatic nerve is the biggest and is 1 cm thick in humans. This is because they control most of the muscles in the lower limbs.


What are cranial nerves?

Cranial nerves are nerves that emerges from the brainstem or the forebrain.


List all motor cranial nerves.

3- oculomotor
4- trochlear
6- abducens
12- hypoglossal


List all sensory cranial nerves

2- optic
8- vestibocochlear


List all motor and sensory cranial nerves.

5- trigeminal
7- facial
9- glossopharyngeal
10- vagus
11- spinal accessory


What is the different between the the optic and olfactory nerve compared to the other cranial nerves?

They are the extensions of the forebrain.
The nerve fibres are covered with meninges and CSF.
Their myelin is made of oligodendrocytes whilst all other cranial nerves are cover by myelin made by Schwann cells.


What are the functions of the olfactory and optic nerve?

The olfactory nerve supplies the sense of smell(special sensory)
The optic nerve supplies the retina for the sense of vision(special sensory).


What are the functions of the cranial nerve 3?

The third cranial is the oculomotor nerve. It controls four out of the six eye muscles(somatic motor), the constriction of the iris and pupil(visceral motor), and also the lifting muscles in the upper eyelid(somatic motor).


What happens when the third cranial nerve is damaged?

If the third oculomotor is damaged, the person suffers from oculomotor nerve palsy, which causes the eyes to be pulled downwards and outwards, have dilated pupils, drooping eyelids, and the inability to focus on nearby objects. Since the eyes are uncoordinated, the patient suffers from strabismus.


What is the role of cranial nerve 4?

The fourth cranial nerve or trochlear nerve supplies the superior oblique muscle of the eye. If damaged, it causes the eyeball to find it harder to look inward or downwards.


What is the role of cranial nerve 5?

The fifth cranial nerve or trigeminal nerve receives the sensations from the skin of the face an controls masticatory muscles. Sometimes infected with herpes zoster, painful vesicles can appear especially in the forehead and upper eyelid. Usually clears up but patient might experience debilitating pain for over months. Can be treated with an antiviral drug if treatment is started early.


What is the role of cranial nerve 6?

The sixth cranial nerve or abducens nerve controls the lateral rictus muscle of the eyes.


What is the role of the cranial nerve 7?

The seventh cranial nerve or facial nerve controls the muscles of facial expression and receives taste sensation from the front of the tongue. It also supplies the submandibular, sublingual and lacrimal gland. Damage can cause bell palsy, paralysis of one side of the face characterised by drooping lips and eyelids. The taste sensation from the front two thirds of tongue is lost. The damage is often caused by viral infections.


What is the role of cranial nerve 8?

The eight cranial nerve receives auditory, and head position and movement information from the cochlear and vestibule system respectively. Can be damaged by infections, drugs, tutors, and an inflammatory disease called Meniere disease. Severe damage can cause permanent deafness, vertigo and loss of balance. Less severe cases have tinnitus and vertigo.


What is the role of cranial nerve 9?

The ninth cranial nerve or glossopharyngeal nerve detects blood pressure changes, receives taste sensations from the back of the tongue, controls a muscle of the pharynx and the parotid gland.


What is the role of cranial nerve 10?

The cranial nerve supplies to the control and receives sensations of all internal organs from the neck to the brim of the pelvic. It also controls the muscles of the pharynx and larynx.


What is the role of cranial nerve 11?

The eleventh cranial nerve or the accessory/spinal accessory nerve helps the vagus nerve in the supply of the pharynx.


What is the role of cranial nerve 12?

The nerve controls the muscles of the tongue and damage can cause the protruded tongue to deviate to the side of the damaged nerve.


What is the sympathetic and parasympathetic outflow?

The sympathetic outflow is from the region T1 to L2
The parasympathetic outflow is the cranial nerves 3,7,9 and 10, and the region S2-S4(In humans, in mice it is S1-2)


What mainly controls both the branches of the autonomic nervous system?

Mostly hypothalamus, but to a lesser extent even some nuclei in the hindbrain such as the solitary nucleus.


What is the role of the adrenal medulla?

It secretes adrenaline directly into the blood stream amplifying and sustaining the response of the sympathetic nervous system to stress.


What does the sympathetic system work on?

It works on the heart, lungs, gastrointestinal area, bladder, rectum, genitals, circulation of blood to muscles and skin, sweat secretion and chicken skin.


What is the difference between the use of ganglion pain the sympathetic and parasympathetic nervous system?

The parasympathetic has no ganglions or ganglions located closer to the target. Therefore, it has specific targeted approach. Sympathetic has ganglions located closer to the spinal cord which spreads the effect to a huge area.


What are the control centres of the bladder emptying?

There is a nucleus called the Barrington nucleus closer to the locus coeruleus, which commands the bladder to empty. A nearby group of cell can command the stop of urine by causing the urethra to contract.


What is the enteric nervous system?

The enteric nervous system is a part of the parasympathetic nervous that is embedded in the wall of gastrointestinal organs. It is arranged in two layers submucosal and myenteric plexuses of the gut wall. It receives and processes the information such as the nature of gut content and gut distension and then integrates it with the input of the autonomic nervous system. It is capable of sophisticated coordination and exhibits plasticity and learning in response to change in dietary habits or gut disruption,