Intro to brain structure and function

what are the layers of the brain (superficial-innermost)

• scalp + loose connective tissue, periosteum

• bone

• dura mater

• arachnoid mater

• pia mater

where can spread of infection occur between in brain

• from scalp to cranial cavity or brain via emissary veins

what are the 3 meninges

• dura mater (thick, tough)

• arachnoid mater (blood vessels beneath, more flexible)

• pia mater (closely applied to brain matter→ follows contours of brain = very thin)

what are the 3 dural reflections/folds of the dura mater

• falx cerebri (related to cerebral cortex)

• tentorium cerebelli

• falx cerebelli (related to cerebellum)

what does rostral mean

anterior

what does caudal mean

posterior

what is parietal formaina

small crevices in bone of brain→ contain emissary veins

what is the string-like structure in arachnoid mater

trabeculi = connective tissue

what is sub-arachnoid space used for

harbouring CSF

what direction does falx cerebri run

sagittally and vertically

what shape is falx cerebri

sickle-shaped

what direction does tentorium cerebelli run

horizontally

which direction does falx cerebelli run

sagittally

what partially separates the two cerebral hemispheres

by falx cerebri

what separates cerebella hemispheres

falx cerebelli

what does tentorium cerebelli separate

separates occipital lobe and back of cerebral hemispheres

and occipital lobe from cerebellum

what structures are found at margins of falx cerebri

• superior sagittal sinus

• inferior sagittal sinus

what is a structural feature of arachnoid mater

arachnoid granulations

what occurs in arachnoid granulations

reabsorption of CSF occurs- keeps it in circulation

what type of haematoma is shown here

subarachnoid heaematoma

what type of haematoma is shown here

subdural haematoma

what type of haematoma is shown here

epidural haematoma

what does arachnoid mater contain

• blood vessels

• CSF

• granulations

what creates foldings of brain

cortical sulci and cortical gyri

what sulcus is in front of central sulcus

precentral sulcus

what sulcus is behind central sulcus

post central sulcus

what are coritcal gyri

• elevated parts/ridges of brain

what gyrus is found in front of central sulcus

precentral gyrus= primary motor cortex

what gyrus is found behind centra sulcus

post central gyrus= primary (somato)sensory cortex

what are the 4 lobes of the brain

• frontal

• parietal

• temporal

• occipital

what is frontal lobe responsible for

• personality

• attention

• motivation

• planning movement

what is parietal lobe responsible for

• integrating sensory info

• language processing

what is temporal lobe responsible for

• memory

• sensory processing

• language comprehession

what is occipital lobe responsible for

• vision

what are the 3 structural parts of brain derived from embryological structure

• hindbrain (rhombencephalon)

• midbrain (mesencephalon)

• forebrain (prosencephalon)

what 2 structures does hindbrain differentiate into

metencephalon

mylencephalon

what structures are derived from metencephalon

• pons

• cerebellum

what structure is derived from mylencephalon

medulla oblongata

what structure does midbrain differentiate into

mesencephalon

what structures are derived from mesencephalon

• tectum (colliculi)

• tegmentum

• peduncles

what structures does forebrain differentiate into

• diencephalon

• telencephalon

what structures are derived from diencephalon

• thalamus

• hypothalamus

what structures are derived from telencephalon

• basal ganglia and cortex

what are the 3 aspects of brain stem (superior- inferior)

• midbrain

• pons

• medulla oblongata

which cranial nerve branches off superior from cerebral peduncles

oculomotor nerve (3rd cranial nerve supplying eye)

which cranial nerve lies beneath cerebral peduncles

trochlear nerve

why is the red nucleus red

enriched with iron

what function is cerebllum responsible for

• balance

• coordination

• synchronisation of muscles

what is found in ventricles

CSF

what volume of CSF is exchanged 3 times/day

150ml

how much CSF is produced approx. each day

500 ml

function of CSF

• assists in circulating substances

• provides cushioning

• absorbs shock

where is CSF produced

choroid plexus (cells that line ventricles)

what is CSF exchanged between

ECF and blood stream

accumulation of CSF in ventricles causes what

hydrocephalus

what septum covers lateral ventricle

septum pellucida

which part of the brain contains the cerebral aqueduct

midbrain

what vertebral level in an adult can you take CSF samples

L3-L4

L4-L5

what vertebral level in infants is it safe to take CSF samples

• at or below L4-L5

what are the ventricles

• inter-connected, fluid filled cavities

• cushion brain

• bathe it in CSF

components of ventricles

• lateral ventricles

• third ventricles

• cerebral aqueduct

• fourth ventricle

what is the arterial supply of brain

• internal carotid artery

• vertebral arteries

terminal branches of internal carotid artery

• anterior cerebral aa

• middle cerebral aa

what do vertebral arteries join to form

• basilary artery

what does basilar artery give rise to

posterior cerebral arteries

what is circle of willis

formed from cerebral blood supply

major anastomosis for brain

what arteries form subcortical blood supply

• anterior cerebral artery

• lenticulostriate arteries

• middle cerebral artery

which sinuses form surface venous drainage

• superior sagittal sinus

• confluence of sinuses

• transverse sinuses

• sigmoid sinus

what sinuses and veins form medial venous drainage

• inferior sagittal sinus

• straight sinus

• internal cerebral veins

what structures from blood brain barrier

• endothelial tight junctions

• basement membrane

• pericytes

• astrocytes

what is blood brain barrier

ensures circulatory system (blood) is kept separate from extracellular fluid

basement membrane surrounds what cells

endothelial ccells

label the cortical sulci

• left= precentral sulcus

• right= central sulcus

• bottom= lateral sulcus

label the cortical sulci

• left= central sulcus

• right= precentral sulcus

• bottom= parieto-occipital sulcus

label the sulci

top left= marginal sulcus

top right= parieto-occipital sulcus

lower left= cingulate sulcus

lower right= calcarine sulcus

label the gyri

• left= precentral gyrus

• right= postcentral gyrus

label the lobes

• top left= frontal

• top right= parietal

• bottom right= occipital

• bottom left= temporal lobe

label from top to bottom

• cerebral hemisphere

• corpus callosum

• ventricle

• diencephalon

• midbrain

• pons

• medulla

inferior view of brain ventral view of midbrain

cerebral peduncles

posterior view of brain with dorsal view of midbrain

• tectum: superior and inferior colliculi

label top labels of transverse midbrain

• top left→ cerebral aqueduct

• middle top→ tectum

• top right→ periaqueductal grey

label bottom labels of transverse midbrain

• bottom left→ substantia nigra

• bottom middle→ cerebral peduncles

• bottom right→ red nucleus

what is cerebellum responsible for

• balance

• coordination

• synchronisation of muscles

components of midbrain

• cerebral peduncles

• substantia nigra

• red nucleus

• tectum

• reticular formation

what are cerebral peduncles responsible for

motor tracts

what is the tectum responsible for

vision and hearing

what is reticular formation responsible for

consciousness

role of pons

some direct connections with cortex

what is medulla responsible for

• respiration

• heart rate

• vomiting

• sneezing

role of thalamus

• major relay station for sensory information from body

role of hippocampus

• memory

• spatial navigation

role of hypothalamus

• hormone synthesis

• temperature

• hunger

• thirst

• sleep

what is role of caudate nucleus and putamen (basal ganglia)

• planning movement

• cognition

• emotion

label ventricular system

• top= lateral ventricles

• middle side= interventricular foramen

• bottom right= third ventricle

• middle bottom= cerebral aqueduct

• bottom left= fourth ventricle

label ventricular system

• top right= lateral ventricle

• top left= interventricular foramen

• middle= third ventricle

• left bottom= cerebral aqueduct

• right bottom= fourth ventricle

Label left side (top to bottom)

• superior sagittal sinus

• choroid plexus

• interventricular foramen

• third ventricle

• interpeduncular cistern

• cisterna pontis

label right side top to bottom

• arachnoid granulation

• lateral ventricle

• cerebral aqueduct

• fourth ventricle

• cisterna magna

label left side top to bottom

• midbrain

• colliculi

• cerebral aqueduct

• fourth ventricle

• cisterna magna

• cisterna pontis

label right side top to bottom

• lateral ventricle

• inter-ventricular foramen

• third ventricle

• interpeduncular cistern

label the arteries

• top= middle cerebral artery

• bottom left =basilar artery

• bottom middle= vertebral artery

• bottom right= superior cerebellar artery