Sem 4 Week 6 Lecture 4

Front 1

CNS has

Back 1

-high metabolic requirements
-requires 10-20% of cardiac output
-vunlnerable to interruption of blood flow

Front 2

Auto-regulation of cerebral blood flow maintains adequate perfusion even when

Back 2

Arterial BP changes significantly or if blood gases change.

Front 3

Circle of Willis

Back 3

-provides arterial supply to brain
-formed by vertebro-basilar system and Internal Carotid system
-anastomose to form a circle which allows blood to reach brain if one is damaged.

Front 4

Vertebro-basilar artery

Back 4

Through vertebral artery coming via foramen magnum.

Front 5

External carotid artery

Back 5

-Doesnt go into cranial cavity
-supplies head,face,skull
-middle meningeal artery

Front 6

Vertebral artery goes thru

Back 6

transverse foraminae of C1-C6 BUT NOT C7 !!

Front 7

ICA goes thru

Back 7

carotid canal

Front 8

Vertebral artery hooks around

Back 8

C1

Front 9

Vertebral artery unite at level of

Back 9

PONS

Front 10

Post. Communicating Artery between

Back 10

ICA & PCA

Front 11

Superior Cerebellar artery supplies

Back 11

Top of cerebellum

Front 12

Ant. Inferior Cerebellar Artery supplies

Back 12

Inferior surface of cerebellum

Front 13

Posterior Inferior Cerebellar Artery supplies

Back 13

Inf. surface of cerebellum.

Front 14

Anterior Cerebral Artery supplies

Back 14

MEDIAL part of FRONTAL + PARIETAL lobes

Front 15

Territories for ACA include

Back 15

Motor and sensory cortices for lower limb.

Front 16

ACA arches over

Back 16

corpus callosum

Front 17

MCA supplies

Back 17

LATERAL surface of brain including parts of frontal ,parietal and occipital lobes + Insula

Front 18

Territories include

Back 18

Motor + sensory cortices for:
-most of body(except lower limb)
-parieto-occipital assoc. areas
-language areas

Front 19

PCA supplies

Back 19

MEDIAL & INFERIOR surfaces of temporal + occipital lobes

Front 20

Territories of PCA include

Back 20

Visual cortex

Front 21

Lenticulostriate arteries supply

Back 21

Basal ganglia and Internal capsule.

Front 22

Pontine branches supply

Back 22

ventral pons.

Front 23

Small perforating branches supply

Back 23

-deep structures where they come off main arteries
-optic chiasm,Ant. hypothalamus
-ventral midbrain
-Post. hypothalamus & thalamus

Front 24

Lenticulostriate arteries come off

Back 24

MCA

Front 25

WHich arteries supply midbrain?

Back 25

-PCA + superior cerebellar artery

Front 26

What supplies pons ?

Back 26

Basilar artery

Front 27

What supplies ventral(MEDIAL) medulla?

Back 27

Ant. spinal arteries

Front 28

WHat supplies posterior part of medulla?

Back 28

PICA

Front 29

Medial part of medulla consists of

Back 29

-Medial lemniscus
-Pyramids
-hypoglossal nucleus

Front 30

Medial medullary syndrome

Back 30

Cerebrovascular syndrome associated with Ant. Spinal Artery

Front 31

Medial medullary syndrome

Back 31

-ipsilateral paralysis & atrophy of tongue(LMN)(hypoglossal nucleus)
-Contralateral somatosensory hemideficit(medial lemniscus)
-Contralateral hemiparesis-->UPM (CST)

Front 32

Ant. Spinal arteries give off

Back 32

Circumferential branches

Front 33

Opthalmic artery

Back 33

Passes into orbit : -->eye(including retina),top of nasal cavity and frontal scalp.

Front 34

Anterior choroidal artery supply

Back 34

Structures in deep LATERAL hemispheres--> optic tract,lateral ventricles,hippocampus

Front 35

Cerebral veins run in

Back 35

Subarachnoid space and drain into a series of sinuses

Front 36

Pathway of venous blood from cerebral veins to Internal Jugular Vein.

Back 36

cerebral veins-->superior sagittal sinus--> confluence of sinuses-->transverse sinus-->sigmoid sinus-->IJV

Front 37

Each venous sinus is

Back 37

A space between 2 layers of dura

Front 38

Dura consists of

Back 38

-Endosteal layer
-meningeal layer

Front 39

How does CSF get to venous system?

Back 39

Via arachnoid villi in superior sagittal sinus.

Front 40

What can diffuse across BBB ?

Back 40

Gases and some lipid soluble susbtances

Front 41

What are actively transported across BBB?

Back 41

Glucose and A.A

Front 42

Lack of glc and O2 in brain causes

Back 42

Permanent capillary occlusion due to swelling of endothelial lining of cerebral capillaries only after a few minutes w/o blood.

Front 43

Brain makes up

Back 43

2% of adult body weight.

Front 44

How many carotid and vertebral arteries make up brain's arterial system?

Back 44

2 carotid and 2 vertebral.

Front 45

ICA enters cranial cavity thru

Back 45

Carotid canal

Front 46

Carotid canal is found in

Back 46

Middle cranial fossa

Front 47

ICA gives off anterior choroidal artery which supplies

Back 47

Anterior Hippocampus and Posterior limb of Internal Capsule.

Front 48

MCA supplies

Back 48

Lateral cortical convexity

Front 49

Deep perforating branches arise from

Back 49

ACA supplying frontal lobe + superior cortical areas as far back as the parietal lobve.

Front 50

Each vertebral artery in the neck loops backward and upwards around atlas(C1) to pierce dura and enter cranial cavity thru foramen magnum.

Back 50

True

Front 51

Shortly after entering cranial cavity,vertebral artery gives

Back 51

PICA

Front 52

PICA supplies

Back 52

-Inferior part of cerebellum
-lateral third of medulla
-choroid plexus of 4th ventricle

Front 53

2 vertebral arteries fuse on

Back 53

Ventral surface of medulla to form basilar art.

Front 54

What happens at the rostral border of pons?

Back 54

Basilar artery terminates by branching into 2 post. cerebral arteries(send deep perforating branches into cerebrum)

Front 55

PCA pass backwards around

Back 55

Cerebral peduncles

Front 56

RAS

Back 56

maintain consciousness

Front 57

PCA continue backwards to supply

Back 57

Occipital lobe

Front 58

Post. choroidal artery supply choroid plexus of 3rd + lateral ventricles.

Back 58

True

Front 59

Ateriolar branches of surface vessels perforate brain tissue at

Back 59

Right angles to supply deep tissues.

Front 60

Larger perforating branches from circle of Willis supply

Back 60

Midbrain,diencephalon,corpus striatum + internal capsule.

Front 61

Perforating branches of ACA supply

Back 61

preoptic and suprachiasmatic regions of hypothalamus.

Front 62

Lenticulostriate arteries supply

Back 62

-Striatum
-Anterior thalamus
-major portion of internal capsule.

Front 63

Post. perforating branches supply

Back 63

Anterior + medial portions of thalamus,subthalamus,middle and post. regions of hypothalamus AND the MEDIAL parts of cerebral peduncles.

Front 64

Borders of territories of the ACA,MCA and PCA are called

Back 64

Watershed areas(areas of marginal blood flow)-where small anastomoses link the ends of cerebral arteries.

Front 65

Perforating vessels supplying deep brain regions

Back 65

lack anastomoses and are called END-ZONES.

Front 66

Aneurysms

Back 66

Dilations in wall of an artery and often develop at sites of branching of arteries in and near ARTERIAL CIRCLE.--> swellings have thin walls that can rupture or leak--> subarachnoid haemorrhage.

Front 67

Major venous system of bran consists of

Back 67

cerebral veins

Front 68

Cerebral veins

Back 68

-have very thin walls
-no muscular layer
-no valves
-lie in subarachnoid space

Front 69

Both set of veins empty into

Back 69

Dural venous sinuses--> IJV

Front 70

Dural venous sinuses

Back 70

Endothelium-lined venous channels surrounded by dura and periosteum.

Front 71

Superficial cerebral veins drain

Back 71

Cortex and adjacent white matter--> then empty into SSS or cavernous sinus.

Front 72

Deep veins drain

Back 72

-Basal ganglia
-Diencephalon
-Nearby white matter
---> empty into straight sinus.

Front 73

Superior sagittal and straight sinuses join at

Back 73

Confluence of sinuses

Front 74

Transverse sinuses arise from

Back 74

Confluence of sinuses and connect with IJV

Front 75

Trauma to the head may tear a superior cerebral vein,resulting in

Back 75

SUBDURAL haemorrhage.

Front 76

Ventral spinal cord is supplied by

Back 76

SINGLE Anterior Spinal artery

Front 77

Dorsal spinal cord supplied by

Back 77

2 or more posterior spinal arteries.

Front 78

Except most ROSTRALLY, ant. and post. spinal arteries are fed along their course by several

Back 78

Segmental spinal arteries -arise from segmental branches of aorta & iliac arteries.

Front 79

Ant. spinal VEINS run along

Back 79

Midline

Front 80

Post. spinal VEINS run along

Back 80

Line of ventral and dorsal roots

Front 81

Ant. and Post Spinal veins drain into

Back 81

Ant. and Post. Radicular veins---> empty into epidural venous plexus.

Front 82

Calibre of cerebral BV controlled by 2 main types of autoregulation:-

Back 82

1.Mechanoregulation via fluctuations in systemic BP.
2.Chemoregulation via blood or tissue gases and pH

Front 83

When systemic BP increases,

Back 83

brain arterioles constrict.

Front 84

Normal individuals have a constant cerebral blood flow between

Back 84

Mean arterial pressure of 60-150 mmHg

Front 85

When arterial CO2 is raised,

Back 85

brain arterioles dilate and cerebral blood flow increases.

Front 86

Blood flow to brain measured by

Back 86

-PET
-fMRI

Front 87

PET

Back 87

-computer generated image based on metabolism of injected radioactively labelled substances
-records local variations in blood flow,reflecting neural activity.

Front 88

fMRI

Back 88

-relies on magnetic signals detected in an activated brain region in relation to its degree of oxygenation

Front 89

Depending on the degree to which it is saturated by O2,

Back 89

Hb can alter the magnetic signal detected in tissue exposed to magnetic fields used for MRI.