ppt 2 part 2 of brain structures/functions

what is the function of the cerebellum(1) ______ of muscle movements (2)

the function of the cerebellum is motor coordination, blueprints of muscle movements

what is the purpose of the corpus callosum?

connects the 2 cerebral hemispheres for communication

what is the purpose of the thalamus

processing for incoming sensory info and relay center (helps process signals) for cerebral cortex communication

what is the purpose of hypothalamus

“involuntary control center”

what is the purpose of the epithalamus

connects the limbic system with other parts of the brain

what is the function of the pineal gland

secrete melatonin; regulates circadian rhythm

function of midbrain

connector between brainstem & thalamus, unconscious and startle reflexes

function of longitudinal fissue

completely divides cerebrum into left and right hemispheres

function of pons

smoothens & modifies signals from medulla oblongata (sleep, respiration)

function of medulla Oblongata

contains the vital centers+ tracts connecting brain and spinal cord

function of pituitary gland & where does it sit

sits in the sella turcica and regulates growth

review* what are the layers of the meninges (3)

1. dura matter

2. arachnoid matter

3. pia matter

what are ventricles? what are they filled with? they are continuous with the….

1. ventricles are hollow spaces within the brain

2. ventricles are filled with cerebrospinal fluid (CSF)

3. ventricles are continuous with central canal

when it comes to forebrain midbrain hindbrain, where are each of the ventricles located?

• Forebrain-lateral and 3rd ventricles

• Midbrain- cerebral aqueduct

• Hindbrain- 4th ventricle

where does cerebrospinal fluid come from? what does it have that makes up CSF? what is the purpose of CSF?

it is produced by choroid plexus in the ventricles

The choroid plexus has capillaires that filters blood plasma to make CSF

CSF cushions the brain

if there is no proper drainage of CSF where does it collect?

CSF collects in ventricles if it does not properly drain

Cerebrospinal fluid and ____) lessens impact of the brain with the skull in case of an accident

duramater

what is the blood drainage structure in the brain?

dural sinus

the dural sinus collects csf from? how does this structure “articulate” with arachnoid granulations

arachnoid granulations (villi)

arachnoid granulations (villi) project into the dural sinus

explain what hydrocephalus is? what is it a side effect of ? how can it be treated?

1. hydrocephalus collection of CSF in brain ventricles

2. a side effect of down syndrome

3. can be treated by aspirating fluid (draining it)

how many pathways/routes are there for blood to reach the brain?

2

name order of 1st arterial pathway into brain— what does it travel up through?

• common carotid artery

• internal carotid artery

• travels up through carotid canal

name order of 2nd arterial pathway into brain—

the vertebral artery runs along the ____ and passes through the _________. Once inside this it becomes ____ artery

• subclavian artery

• vertebral artery

• basilic artery

the vertebral artery runs along the spine and passes through the foramen magnum once inside, it becomes the basilar artery

both arterial roots meet where?

the circle of willis

what forms the circle of wills? describe its form/shape what sits in the middle of it .

if you look at an inferior view of the brain (bottom) you can see two internal carotid arteris coming from the sides and the basilar artery coming from below. when they connect they form a loop which is the circle of willis

the pituitary gland sits in the middle of the circle of willis

what is the purpose of the circle of willis

it is a safety net, if one artery is blocked blood can reroute through the orther side

how many pairs of arteries branch of the circle of willis, what do they supply?

NAME THEM and state what part of the brain they supply (broadly)

3 pairs of arteries these arteries supply the brain itself

1. anterior cerebral arteries- supply the front of the brain

2. middle cerebral arteries- supply the sides of the brain

3. posterior cerebral arteries- supply the back of the brain

where does the basilar artery feed into in the circle of willis?

posterior part of the circle

venous drainage order from the brain(1) what foramen is passed? (2)

dural sinus drains into

PASSES THROUGH JUGULAR FORAMEN

internal jugular vein drains into

brachiocephalic vein

what is a sinus? give me 3 examples of sinus’s you’ve learnt in this course what do each of those sinus’s collect

• a sinus is a hollow space

• We’ve learnt abut the coronary sinus-collects deoxygenated blood and carries it to right atrium

• paranasal sinus- air filled hollow space that fills when congested

• dural sinus - blood filled space built in dura mater folds

what is the longitudinal fissure? what sits underneath it (it is connective tissue)

• longitudinal fissure is a “line”/ grove that goes down midline of brain between both hemispheres

• The corpus callosum sits underneath

the dura matter has 2 layers what are they and can you describe their characteristics?

• OUTER LAYER:Periosteal layer- fused directly to inside of skull bone (inner lining of skull)

• INNER LAYER: Meningeal layer- folds into brain fissures

from outer to inner what is the order of the meninges

• dura mater

• arachnoid mater

• pia mater

What is the dural fold and what is its job? whats another name for it

A sheet of dura mater that dips down between the two cerebral hemispheres

(called the falx cerebri).

Its job is to act as a divider/wall between the hemispheres.

the tentorium cerebeli is a a dural fold between where? is it vertical or horizontal fold

it is a dural fold between cerebrum and cerbelum

it is a horizontal fold

falx cerebi is located where and divides what

falx crebri is the most posterior dural fold, it divides the two hemispheres of the cerebellum careful not to confuse this with cerebrum

each dural fold has a sinus, how many are running along the edge of falx cerebri what are thier names?

FALX CEREBRI SINUS’S

• Superior saggital sinus

• inferior saggital sinus

each dural fold has a sinus, how many are running along the edge of tentorium cerebelli what are thier names? which ones are paired? which one is not on the edge of the sinus

TENTORIUM CEREBELLI SINUS’S

• straight sinus

• transverse sinus (paired)

sigmoid sinus (paired) NOT on edge (more function as drainage)

what does paired mean

it comes in two, there is one on each side of the brain

what is the confluence of sinus’s

where are the sinus’s pool together in the back of the brain

where is the Cavernous sinus? is it paired? where does it drain?

• the cavernous sinus is at the base of the skull (near sella turcica and pituitary gland)

• yes it is paired

• it drains toward front of brain

what is the order of blood drainage in the sinus’s remember there is two starting points

superior sagittal sinus drains into. | Inferior saggital sinus drains into

transverse sinus drains into | straight sinus drains into

sigmoid sinus drains into

internal jugular vein drains into

brachiocephalic vein

sinuses do not have any valves meaning….

blood can flow any direction

how is cerebrospinal fluid produced and drained

chorid plexus produces CSF → CSF ciruculates through ventricles around brain → arachnoid granulations absorb it back into dural sinus → blood drains through the venous drainage pathway