1
Q
what are the 3 parts of the brain stem?
A
1) Midbrain
2) Pons
3) Medulla oblangata
2
Q
what do the cranial nerves supply?
A
exit the brainstem and supply:
- 4 special sense organs in the head responsible for vision, smell, taste and hearing
- (in addition they supply intrathoracic and intraabdominal viscera)
3
Q
where do the peripheral nerves supply?
A
Peripheral nerve roots exit the spinal cord to both sides of the body:
supply sensory and motor fibres to the trunk and limbs
4
Q
what are the 12 cranial nerves?
A
Olfactory Optic Occulomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glassopharynx Vagus Spinal Accessory Hypoglossal
5
Q
what are the meninges of the brain?
A
From brain outwards:
1) pia layer
2) subarachnoid space (filled with cerebrospinal fluid)
3) arachnoid layer
4) dura layer
5) skull
6) skin
6
Q
what is the function of the cerebrospinal fluid (CSF)?
A
- buoyancy
- protection
- clearing wastes
- homeostasis
7
Q
what does it mean for the brain to be high convoluted an what is the purpose of this?
A
- many folds and creases
- a large surface area of brain to fit in the skull
8
Q
what is grey matter and what is white matter?
A
reffers to its apperance in a nerve cell,
- grey matter is the nerve cell body
- white matter is the axon and the myelinated sheath is what gives it this white appearence
9
Q
what is the commissure?
A
-connects the two cerebal hemispheres of the brain
10
Q
what is a ganglion/ ganglia ?
A
- a collection of nerve cell bodies
11
Q
what is a fasicullis and a funicullis and tract?
A
- fasicullis is a bundle of axons and multiple falliculli are known as a funicullis
- then multiple funiculli form a tract
12
Q
how many pairs of nerves are there from the CNS?
A
31 pairs
13
Q
how do the cervical nerves correspond to the vertrbrae?
A
- there are 7 cervical vertebrae but 8 cervical nerves.
- c1 nerve is above c1 vertebrae etc…( same foe each)
- nerve C8 emerges below vertebrae C7
14
Q
how are the spinal nerves in the cervical region different to those in thoracic, lumbar and saccryal ?
A
- in thoracic, lumbar and saccryal regions nerves emerge below the vertebrae
- in the cervical region nerves emerge above the vertebrae
15
Q
what is the gyrus and sulcus?
A
- gyrus is a fold of tissue and the sulcus us the depression after it
16
Q
what is the importance of the central sulcus?
A
- anterior to central sulcus is the motor cortex (pre central gyrus)
- posterior to central sulcus is the sensory cortex (post central gyrus)
17
Q
name the lobes of the brain?
A
- parietal lobes
- frontal lobes
- occipital lobes
- temporal lobes
- cerebellum
18
Q
what is the corona radiata?
A
a fan-shaped mass of white matter fibers passing to and from the cerebral cortex.
19
Q
what is the function of the corpus callosum?
A
- connects right and left hemisphere to communicate with each other
20
Q
what are the 3 regions of the corpus callosum?
A
anterior -genu (latin for bend) -body -splenium posterior
21
Q
where does the cerebellum sit?
A
- posterior cranial fossa
22
Q
where does the spinal cord become not bundled?
A
L1, conus medullaris
23
Q
where nerves for the arms and neves for the legs come off the spinal cord?
A
arms : cervical enlargment
legs: lumbar enlargment
24
Q
why is thoracic spinal cord different?
A
cervical, lumbar, sacral : posterior and anterior horns
thoracic: posterior, lateral and anterior horns
25
where are the sympathetic nerve bodies?
lateral horn in the spinal cord between T1 and L2
26
what is the function of the olfactory nerve (CNI) ?
smell
27
what is the function of the optic nerve (CNII) ?
vision
28
what is the function of the oculomotor nerve (CNIII) ?
muscles in the eye
29
what is the function of the trochlear nerve (CNIV) ?
superior oblique muscle in the eye
30
what is the trigeminal nerve (CNV) split into and whats its function?
ophthalmic - scalp, forehead and nose
maxillary - cheeks, lips and upper mouth/ teeth
mandibular - tongue, lower mouth and muscles of mastication
31
what the function of the Abducens nerve (CNVI) ?
Lateral rectus muscle in the eye
32
what is the function of the facial nerve (CNVII)?
controls the muscles that help you smile, frown, wrinkle your nose, and raise your eyebrows and forehead.
33
what is the function of the vestibulocochlear nerve (CNVIII) ?
hearing and balance
34
what is the function of the glossopharyngeal nerve (CNIX)?
provides motor, parasympathetic and sensory information to your mouth and throat.
35
what is the function of the vagus nerve (CNX)?
the regulation of internal organ functions, such as digestion, heart rate, and respiratory rate, as well as vasomotor activity, and certain reflex actions, such as coughing, sneezing, swallowing, and vomiting
36
what is the function of the spinal accessory nerve (CNXI)?
controls the movement of certain neck muscles.
37
what is the function of the hypoglossal nerve (CNXII)?
controls muscles invloved with movement of the tounge (anteriorly)
38
what are 4 types of glial cells?
Any of the cells that hold nerve cells in place and help them work the way they should:
Astrocytes, Oligodendrocytes, Microglia, Ependymal cells
39
what is the appearence of astrocytes (most common glial cells) ?
Astrocytes are star-shaped glial cells within the brain and spinal cord, and they can have multiple functions
40
what are the functions of astrocytes ?
Metabollic- stores glycogen to be broken down to glucose as fuel for neurone
Regulate extracellular ionic movement - prevents spontaneous depolarisation
Neurotransmitter from extracellular fluid- removes excess neurontransmitters
Control synaptic transmission - some astrocytes release ATP to increase adenosine which inhibits neurone transmission
41
what is the function of Oligodendrocytes (type of glial cell) ?
responsible for insulating the axons in the CNS, produce a myellin sheath.
(equivalent to schwarnn cells in the peripheral nervous system)
42
what is the function of microglia cells (type of glial cells)?
Form the resident immune system of the brain, activated in response to tissue damage and can recognise foreign antigens and can initiate phagocytosis to occur
(origin is mesodermal)
43
what is the function of Ependymal cells (type of glial cell) ?
The ependyma is the thin lining of the ventricular system of the brain and spinal cord. This lining is made up of ependymal cells, the basal membranes of which are attached to astrocytes. The main function of these cells is the production of cerebrospinal fluid (CSF) as a part of the choroid plexus.
Their apical surfaces are covered with cilia and microvilli, which allow for the circulation and absorption of CSF respectively.
44
what is thrombosis and what are the 2 main types?
Thrombosis occurs when blood clots block your blood vessels. 2 types are: venous thrombosis and arterial thrombosis
45
what can the complications of thrombosis be?
Complications of thrombosis can be life-threatening, such as a stroke or heart attack.
46
what is the Basal ganglia?
The “basal ganglia” refers to a group of nuclei below the cortex responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.
47
where does CNI (the olfactory nerve) sit?
CN I is responsible for Olfaction and bulbs pass through the Cribiform Plate of the Ethmoid bone to join the bundles.
48
what is the function of the olfactory epithelium and where is it found?
The olfactory epithelium is responsible for smell and is situated on the inferior surface of the cribiform plate as well as the superior nasal conchae
49
what are the 3 types of cells found on the olfactory epithelium?
* Olfactory Receptor cells - first order neurones
* Supporting cells - collumnar epithellium
* Basal cells - stem cells
50
How does an odorant cause a nerve impulse?
1) Odorant binds to olfactory cillium and causes depolarisation and subsequesntly activation of G protein
2) G protein activates adenylate cyclase to form cAMP from ATP
3) cAMP cause Na+ channels to open so the cell becomes depolarised and causes the generator potential
4) If threshold is reached an action potential will be fired along the olfactory axon
51
what are the 3 layers of the wall of the eyeball?
* Fibrous tunic
* Vascular tunic
* Retina (inner tunic)
52
what are the muscles that control the eyeball?
- superior oblique ( moves eye down and out)
- superior rectus (look upwards)
- inferior rectus (look downwards)
- medial rectus (look inwards)
- lateral rectus (looks outwards)
- inferior oblique (looks up and out)
53
what are the two parts of all photopigments?
- opsin (glycoprotein part)
| - retinal (light absorbing part)
54
what is the process of light absorption by the photopigment?
1) In darkness retinal is bent (cis-retinal) and complementary to opsin
2) when cis-retinal absorbs light it straightens and becomes trans-retinal
3) Bleaching, trans-retinal seperates from opsin as no longer complementary
4) retinal isomerase turns trans-retinal back to cis-retinal
5) regeneration, cis-retinal is reformed so is now complementary to opsin again
55
what is the optic nerve formed from?
optic nerve formed from the retinal ganglion on each side
56
what is the optic chiasm?
its where the optic nerves cross
57
what are the three main regions of the ear?
1. External ear, which collects sound waves and channels then inwards
2. Middle ear, which conveys sound vibrations to the oval window;
3. Internal ear, which houses the receptor for hearing and equilibrium.
58
explain what the ear drum is
the tympanic membrane separates the external ear from the middle ear. Its is a very thin membrane with simple cuboidal epithelium internally and connective tissue composed of collagen, elastic fibres and fibroblasts between epithelial layers.
59
what are the 3 organs responsible for stance equillibrium and dynamic equillibrium?
vestibular apparatus, saccule, utricle and semicircular ducts.
60
How do sound waves travel through the ear?
1) auricle directs sound waves into the external auditory canal and towards the tympanic membrane where it vibrates and causes the ossicles to move
2) As stapes moves it causes it footplate which is connected to the oval window tp vibrate
3) this causes movement of the perilymph of the cochlea, as the oval window bulges inwards it pushes the perilymph of the scala vestibule
4. Pressure waves are transferred to the scala tympani and eventually to the round
window and to the endolymph in the cochlear duct.
5. Waves in the endolymph cause the basilar membrane to move the hair cells. The
stereocilia bend and generate a nerve impulse in the first-order neurones of the
cochlea nerve fibres.
6. Sound waves of various frequencies cause different regions of the basilar membrane to vibrate more intensely than others. At the base, (closest to the oval window), high-frequency vibration and at the apex it is tuned for low-frequency sound waves.
61
where is the cavernous sinus found?
The cavernous sinuses are paired and are situated on the body of the sphenoid bone. It runs from the superior orbital fissure to the petrous temporal bone.
62
what are the contents of the cavernous sinus?
```
on lateral wall:
Oculomotor nerve
Trochlear nerve
Ophthalmic nerve
Maxillary nerve
```
contents:
Internal carotid artery (and sympathetic plexus)
Abducens nerve
63
what nerves pass through the superior orbital fissure?
trochlear nerve
ophthalmic nerve
abducens nerve
oculomotor nerve
64
what cranial nerve passes through the foramen rotundum?
maxillary CN V2
65
what cranial nerve passes through the foramen ovale?
mandibular nerve ( CN V3)
66
what cranial nerves pass through the internal acoustic meatus?
facial (CNV||)
| Vestibulocochlear (CNV|||)
67
what cranial nerves pass through the jugular foramen?
glossopharyngeal (CNIX)
vagus (CNX)
spinal accessory (CNXI)
medical sciences
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