Practical 1 - CNS structures, fluid and barriers

Question 1

the brain and spinal cord develope from what?

Answer 1

embryonic neural tube

Question 2

the cranial end of the embryonic neural tube forms what?

Answer 2

the hindbrain, midbrain and forebrain

Question 3

the caudal end of the embryonic neural tube forms…

Answer 3

spinal cord

Question 4

name the lobes of the adult brain

Answer 4

frontal

parietal

occipital

temporal

Question 5

what actaully are the lobes of the brain?

Answer 5

extensivbely folded cerebral cortex

Question 6

what are the gyri and sulci?

Answer 6

crests and grooves of the folded cerebral cortex

Question 7

do some gyri and sulci house important regions?

Answer 7

yep

eg primary motor cortex in pre-central gyrus

Question 8

what are the ventricles?

Answer 8

fluid filled cavities

Question 9

hat do the ventricels contian?

Answer 9

fluid - and the choroid plexus

Question 10

what does the choroid plexus produce?

Answer 10

CSF

Question 11

purpose of CSF

Answer 11

cushions and nourishes the brain from inside (in the ventricles) and outside (in teh subarachnoid space)

Question 12

basically describe the blood supply to the brain

Answer 12

anterior and posterior circulation:

2 internal carotid arteries

2 vertebral arteries

Question 13

what happens if a certain artery suppling the bvrain is occluded?

Answer 13

specific functional deficits

Question 14

what are the 3 expansions at the cranial head of the neural tube?

Answer 14

fore brain

midbrain

hind brain

(spinal cord below)

Question 15

what does the forebrain form?

Answer 15

caudal diencephalon (mainly the thalamus and hypothalamus)

rostral telencephalon (or telencephalic vesicle, one on either side) and these give rise to the cerebral hemispheres.

Question 16

whats the diencephalon?

Answer 16

thalamus and the hypothalamus

Question 17

what is the telencephalon?

Answer 17

forms the cerebral hemispheres

Question 18

what does the midbrain develope into?

Answer 18

mesencephalon

Question 19

what does the hind brain develope into?

Answer 19

Caudal medulla oblongata

rostral pons

Question 20

on what surface does the cerebellum develope?

Answer 20

dorsal surface of the hindbrain

Question 21

picture:

Answer 21

Question 22

Major brain regions:

Answer 22

Question 23

the cerebral hemispheres are folded…..

Answer 23

cerebra lcortex

Question 24

only a proportion of the cerebral cortex is visible where the folds reach the surface: ….

Answer 24

only a proportion of the cerebral cortex is visible where the folds reach the surface: gyri (singular gyrus).

Question 25

Cerebral cortex dips below the surface, resulting in …..

Answer 25

Cerebral cortex dips below the surface, resulting in fissures or sulci (singular sulcus)

Question 26

are gyri and sulci constant between individuals?

Answer 26

No - apart from some main ones

Most of the gyri and sulci are variable between individuals, and between the 2 hemispheres, but some of the larger ones are constant

Question 27

whats the lateral sulcus?

Answer 27

lateral sulcus: a deep fissure in the lateral side, (sometimes called the Sylvian fissure)

Question 28

what does the lateral sulcus separate

Answer 28

separates the temporal lobe from the frontal and parietal lobes

Question 29

whats the central sulcus

Answer 29

Central sulcus: the division between frontal and parietal lobes

Question 30

whats the Parieto-occipital sulcus:

Answer 30

Parieto-occipital sulcus: on the medial surface, separating the occipital and parietal lobes

Question 31

The 4 cerebral lobes are named corresponding to ….

Answer 31

The 4 cerebral lobes are named corresponding to the bones of the skull that overlie them (frontal, parietal, temporal & occipital).

Question 32

Brain surface landmarks

Answer 32

Question 33

On the ventral brain surface (figure 1.4), the _____ and _____ are visible. Because it appears as a bulbous swelling at the top of the cord

Answer 33

On the ventral brain surface (figure 1.4), the medulla and pons are visible. Because it appears as a bulbous swelling at the top of the cord, an older term for the medulla is the bulb (e.g. nerve fibres from cerebral cortex to the medulla are cortico-bulbar fibres.

Question 34

Ventral surface of the brain

Answer 34

Question 35

what is grey matter?

Answer 35

Grey matter refers to the cell bodies and dendrites located in the outer layers of the cerebral cortex and cerebellar cortex, in the deep nuclei (collections of neurons) of the brain, and in the spinal cord dorsal and ventral horns.

Question 36

what is white matter?

Answer 36

White matter refers to the axons that connect different CNS regions, many of which are myelinated, and which may form named nerve tracts

Question 37

In the living brain the grey matter is ______, having many capillaries; in the fixed brain it is _____.

Answer 37

In the living brain the grey matter is pink, having many capillaries; in the fixed brain it is brown.

Question 38

In the spinal cord and brainstem, much of the white matter is located….

Answer 38

In the spinal cord and brainstem, much of the white matter is located on the outer surface.

Question 39

The cerebral and cerebellar cortex have the opposite organisation to the spinal cord.

explain how:

Answer 39

The cerebral and cerebellar cortex have the opposite organisation to the spinal cord: the neurons form a folded outer sheet, with axons running below

poor card i know

Question 40

Deep nuclei (‘sub cortical’) e.g. vestibular nuclei, deep cerebellar nuclei, the amygdala and the basal ganglia, are equivalent to ….. what in the PNS

Answer 40

Deep nuclei (‘sub cortical’) e.g. vestibular nuclei, deep cerebellar nuclei, the amygdala and the basal ganglia, are equivalent to peripheral nerve ganglia

Question 41

function of Glical cells in the CNS>

Answer 41

In addition to neurons, the CNS contains very many glial cells, of which there are several types with different functions (myelination, phagocytosis of debris, homeostatic control of the local neural environment, maintaining a blood-brain barrier)

Question 42

Grey matter can be seen microscopically be using _____ stains (toluidine blue, cresyl violet etc) to stain nuclei and cell bodies (both neuronal and glial)

Answer 42

Grey matter can be seen microscopically be using Nissl stains (toluidine blue, cresyl violet etc) to stain nuclei and cell bodies (both neuronal and glial)

Question 43

White matter can be seen using _____ stains (Weigert-Pal method, osmic acid).

Answer 43

White matter can be seen using myelin stains (Weigert-Pal method, osmic acid).

Question 44

location of Primary motor cortex (Brodmann’s area 4)

Answer 44

Primary motor cortex (Brodmann’s area 4) is anterior to the central sulcus.

Question 45

location of Primary somatosensory cortex (Brodmann’s areas 3, 2 and 1)

Answer 45

Primary somatosensory cortex (Brodmann’s areas 3, 2 and 1) is posterior to the central sulcus.

Question 46

locatrion of Primary visual cortex (area 17)

Answer 46

Primary visual cortex (area 17) is located at the occipital pole, particularly in the calcarine sulcus on the medial face of the hemisphere.

Question 47

location of Primary auditory cortex

Answer 47

Primary auditory cortex is in the lateral temporal lobe.

Question 48

Pain is represented in the …..

Answer 48

Pain is represented in the insula (buried cortex) and in the anterior cingulate cortex, just above the corpus callosum.

Question 49

location of Primary olfactory cortex

Answer 49

Primary olfactory cortex is in the medial temporal lobe.

Olfaction and taste are also represented in parts of the insula.

Question 50

The primary motor and sensory areas of cortex

Answer 50

Question 51

brain ventricles labeled

Answer 51

Question 52

The fluid-filled cavity of the developing cerebral vesicles become….

Answer 52

The fluid-filled cavity of the developing cerebral vesicles become the two large lateral ventricles

Question 53

the two large lateral ventricles are located?

Answer 53

the two large lateral ventricles buried below the cortex of the cerebral hemispheres,

Question 54

how do the 2 lateral ventricles communicate?

Answer 54

communicate via the inter-ventricular foramen (of Munro) with the cavity of the 3rd (III) ventricle, on the midline in the diencephalon (the thalamus and hypothalamus).

Question 55

describe the cerebral aqueduct?

Answer 55

The cavity of the midbrain narrows during development to become the cerebral aqueduct, connecting the 3rd ventricle with the 4th (IV) ventricle in the hindbrain (its roof being formed by the cerebellum).

Question 56

what is the 4th ventricle continuous wiht?

Answer 56

The 4th ventricle is continuous with the central canal of the spinal cord and with the subarachnoid space, via the foramina of Magendie and Luschka

Question 57

what lines the ventricles?

Answer 57

ependyma

Question 58

whats produced at the choroid process?

Answer 58

CFS

Question 59

Matuer ventricular system

Answer 59

Question 60

describe the structure of the choroid plexus

Answer 60

a plexus of blood vessels wrapped in choroid epithelium (formed from pia mater and ependyma), called the choroid plexus, forms CSF from blood in the lateral, 3rd and 4th ventricles

Question 61

attachment of the plexus to adjacent brain structures is known as…

Answer 61

tela choroidea

Question 62

is ther echoroid plexus in the anterior and posterior horns?

Answer 62

no.

but there is in the inferior horn

Question 63

is there choroid plexus in the aqueduct?

Answer 63

nope

Question 64

how does CSF escape the ventricular system

Answer 64

CSF escapes the ventricular system (via the foramen of Magendie and the foramina of Luschka) into the subarachnoid space surrounding the brain and spinal cord.

Question 65

the subarachnoid space is between which meninges?

Answer 65

arachnoid mater and the pia mater.

Question 66

during brain removal - is the dural matter often left on the inner surface of the skull?

Answer 66

yep

Question 67

what does the pia matter cover

is it visible?

Answer 67

The pia mater forms an intimate covering for all superficial parts of the brain and spinal cord, but is not visible to the naked eye

Question 68

what are cisterns

Answer 68

In some places the pia and arachnoid are widely separated to form cisterns containing accumulations of CSF

Question 69

In some places the pia and arachnoid are widely separated to form _____ containing accumulations of CSF

Answer 69

In some places the pia and arachnoid are widely separated to form cisterns containing accumulations of CSF

Question 70

are cisterns separate or connected?

Answer 70

Cisterns are not separate entities but communicate with each other by way of the general subarachnoid space.

Question 71

which are the 2 important cisterns?

Answer 71

The important cisterns are cisterna magna, in the angle between the medulla oblongata and the cerebellum, and the lumbar cistern (from which CSF can be sampled)

Question 72

describe the venous sinuses?

how do they return CSF to the circulation?

Answer 72

formed from the periosteal and meningeal layers of the dura mater

return venous blood from the cerebral circulation via the internal jugular vein

also sites for return of CSF into the systemic circulation via arachnoid villi into the superior sagittal sinus.

Question 73

The brain requires about ____% of resting cardiac output

Answer 73

The brain requires about 15-20% of resting cardiac output

Question 74

and blood flow through the brain approaches …

Answer 74

and blood flow through the brain approaches a litre per minute.

Question 75

2 main pairs of arteries which supply the brain

Answer 75

internal carotid arteries - parts of forebrain

vertebral arteries - brainstem, cerebellum and some ventral and posterior parts of the forebrain

Question 76

which part of the brain do the vertebral arteries supply?

Answer 76

brainstem, cerebellum and some ventral and posterior parts of the forebrain

Question 77

where do most brain blood vessles run?

Answer 77

in subarachnoid space

Question 78

major brain arteries

Answer 78

Question 79

describe the path of the carotid artery

Answer 79

• enters the skull through the carotid canal
• passes through the cavernous sinus in a characteristic S-shape (carotid siphon),
• penetrates the dura into the subarachnoid space.

Question 80

at bifurcation, the carotid artery branches into>?

Answer 80

An anterior cerebral artery

A middle cerebral artery,

Question 81

what does the anterior cerebral artery supply?

Answer 81

frontal lobes

more medial aspects of the parietal and occipital lobes

(include medial aspects of somatosensory and motor cortical areas, which relate to the lower limbs.)

Question 82

describe the path of the anterior cerebral artery

Answer 82

supplies the frontal lobes then passes into the longitudinal fissure where it runs above the corpus callosum to supply more medial aspects of the parietal and occipital lobes.

Question 83

which is the alrgest cerebral artery

Answer 83

mdidle cerebral artery

Question 84

path of the middle cerebral artery

Answer 84

passes into the more lateral and inferior parts of the hemispheres through the lateral sulcus.

Question 85

what do branches of the middle cerebral artery supply

Answer 85

ts branches supply somatosensory and motor cortex relating to upper limb and face, the basal ganglia and cerebral white matter.

Question 86

One or both of the _______ arteries can be found on the ventral aspect of the medulla (they

are frequently unequal in size)

Answer 86

One or both of the vertebral arteries can be found on the ventral aspect of the medulla (they

are frequently unequal in size)

Question 87

where do the vertebral arteries converge? - to form what?

Answer 87

hey converge at the caudal pons to form the midline basilar artery

Question 88

what does the basilar artery groove?

Answer 88

ventral surface of the pons

Question 89

important branches of the basilar artery? (3)

Answer 89

inferior cerebellar arteries (anterior inferior cerebellar artery or ‘AICA’ and posterior inferior cerebellar artery or ‘PICA’

Question 90

ICA, AICA, PICA supply what

Answer 90

These provide the major blood supply to the brain stem (midbrain, pons, medulla)

Question 91

which arteries supply the cerebellum?

Answer 91

PICA AICA and superior cereellar arteries

Question 92

describe ow the basilar artery terminates?

Answer 92

bifurcating into two posterior cerebral arteries which supply the medial occipital lobes, notably visual cortex, and parts of the temporal lobes.

Question 93

cirlce of willis

Answer 93

Question 94

anterior cerebral arteries are united via the …

Answer 94

anterior cerebral arteries are united via the anterior communicating artery

Question 95

Posterior communicating arteries arising from the i………. ……. pass back to anastomose with the posterior cerebral arteries on either side

Answer 95

Posterior communicating arteries arising from the internal carotid or the middle cerebral arteries pass back to anastomose with the posterior cerebral arteries on either side

Question 96

the circle of willis surrounds?

Answer 96

optic chiasm and stalk of the pituitary

Question 97

The cerebral cortex is supplied by …..

Answer 97

The cerebral cortex is supplied by the anterior, middle and posterior cerebral arteries; these have a characteristic area of supply

Question 98

Like CSF, blood in the cerebral vascular system drains into the ,….

Answer 98

Like CSF, blood in the cerebral vascular system drains into the venous sinuses,

Question 99

venous sinuses

Answer 99

Question 100

my mummy says i am gay and have deformed labia; one is

Answer 100

longer than the other. But which? The middle.

Question 101

Superficial veins drain into the…

Answer 101

Superficial veins drain into the superior and inferior sagittal sinuses

Question 102

deep veins drain into the..

Answer 102

deep veins drain into the great cerebral vein and then the straight or transverse sinuses

Question 103

The sinuses lie between ….

Answer 103

The sinuses lie between folds of dura.

Question 104

why is the brainstem a good indicator of death?

Answer 104

if the brain stem is irreversibly damaged then the forebrain, even if undamaged, cannot again function normally.

Brain stem death also indicates a permanent inability to maintain basic homeostatic functions (breathing, cardiovascular control).

Although these can be replaced by life-support machinery, recovery cannot occur after brain stem death

Question 105

Function in the brain stem can be assessed through ….

Answer 105

Function in the brain stem can be assessed through clinical examination of cranial nerve function.

Question 106

describe a cerebrovascular accident

Answer 106

impaired cerebral blood flow

vessel occlusion or vessel rupture / leakage

Loss of blood supply in the territories of each artery gives rise to characteristic clinical symptoms and physical signs

Question 107

why can blood vessel rupture occur?

Answer 107

Vessel rupture can occur due to the bursting of an aneurysm, an excessive localised swelling of the wall of an artery

Question 108

describe an Intracranial haemorrhage

Answer 108

Potential spaces in the cranium are of clinical importance as any bleed (extradural, subdural or subarachnoid haemorrhage) will increase the volume of fluid within the cranium and exert pressure on brain tissue.

Question 109

describe Hydrocephalus:

Answer 109

The narrow passageways in the ventricles are vulnerable to blocking by “space-occupying lesions” (such as tumours) or by intracranial bleeds.

Blockade of CSF flow causes accumulation of CSF proximal to the block, and a rise in pressure, which results in hydrocephalus (lay term, ‘water on the brain’).

This can occur at various sites in the circulatory pathway of CSF, and is a serious clinical condition.

Question 110

what is craniotomy

Answer 110

In neurosurgery, a craniotomy is the surgical removal of a portion of the skull; keyhole surgery is a minimally invasive surgery carried out through a very small incision, with special instruments and techniques including fibre optics.

Question 111

describe Spinal & epidural anaesthesia

Answer 111

The existence of an “epidural” space around the spinal nerves, especially at sacral levels, allows segmental anaesthesia, known as epidural anaesthesia (e.g. for pain relief without general anaesthesia in childbirth).

Anaesthetic can also be introduced into the CSF in the lumbar cistern, a procedure known as spinal anaesthesia, in which the anaesthetic substance acts directly on the spinal cord itself.

Question 112

whats a lumbar puncture

Answer 112

The dural sac, with its lining of arachnoid, extends to the sacrum, forming the lumbar cistern. Within the lumbar cistern a sheaf of spinal roots, the cauda equina (“horse’s tail”), occupies the subarachnoid space. These mobile spinal roots will roll away from a needle introduced through the dura into the subarachnoid space, allowing a sample of CSF to be taken from the lumbar cistern, a lumbar puncture

Question 113

he spinal cord is shorter than the vertebral column; in adults it generally ends….

Answer 113

he spinal cord is shorter than the vertebral column; in adults it generally ends near the lower border of vertebra L1

Question 114

why is a lumbar puncture used?

Answer 114

for diagnostic purposes (e.g. meningitis, subarachnoid haemorrhage), CSF can be obtained from the lumbar cistern as a routine procedure, or more exceptionally from the cisterna magna.

Question 115

describe Cerebral angiography

Answer 115

Cerebral angiography is the visualisation of cerebral vasculature. X-ray angiography requires the injection of radio-opaque fluid into the internal carotid or vertebral vessels. This radiological investigation can be used to examine the vascular tree for constrictions or dilatations. Angiograms can also be generated using MRI, and used in combination with CT (see below).

Question 116

fun info

Answer 116

Structural imaging methods: X-ray Computed Tomography (X-ray CT, or CT) is a form of radiography that uses multiple x-ray images through the brain from different angles to generate a series of continuous slices and produce sectional images of the brain- a CT scan. Nuclear Magnetic Resonance Imaging (MRI) provides images of the brain by measuring regional variations in proton density when placed in a magnetic field and stimulated by a particular radio frequency. MRI images can be produced relatively rapidly and with high resolution and high contrast in any desired plane. The MRI settings may be altered to highlight bone or soft tissues.

Question 117

fun info 2

Answer 117

Functional imaging methods: An advance on MRI allows changes in blood flow to be measured; changes in blood flow may represent changes in metabolic activity, and so this provides a means for assessing changes in brain activity (or function) over time, and is called functional MRI (fMRI). In Positron Emission Tomography (PET), injections of short-lived radioisotopes are given; these attach to a molecule used by the body (e.g. glucose), circulate and are metabolised within the tissues. The high-energy gamma rays emitted by the radioisotopes are detected by the scanner depending on the rates of metabolism or level of blood flow. Radiolabelled ligands can also be used to localise specific receptor types in the living brain with the same method.

Question 118

fat

Answer 118

mamba