Brain formation and fluids

Question 1

Cerebrum/central hemispheres

Answer 1

telencephalon

Question 2

Thalamus and hypothalamus

Answer 2

Diencephalon

Question 3

Telecephalon and diencephalon

Answer 3

Prosencephalon

Question 4

Midbrain

Answer 4

Mesencephalon

Question 5

Pons and cerebellum

Answer 5

Metencephalon

Question 6

Medulla

Answer 6

Myelencephalon

Question 7

myelencephalon and metencephalon

Answer 7

Rhombencephalon

Question 8

Development of the nervous system

Answer 8

Forms early in embryonic life - 3rd week
Develops from ectodermal layer
Neural groove develops in the mid line and neural cells proliferate and form a neural tube
Neural tube forms spinal cord, at the cephalic ( head) end it swells and flexes to form the brain

Question 9

Neuropores

Answer 9

Posterior and anterior neuropores HAVE to close for formation of brain and spinal cord
Posterior - end of spine
anterior - brain
folic acid can help

vertebral column more rapidly than spinal cord

Question 10

3rd month of development - neural tube

Answer 10

Spinal cord extends the entire length of the embryo,spinal nerves pass through the intervertebral foramina at their level of origin

Question 11

How does the neural tube and vertebral column develop past 3 months

Answer 11

Vertebra column and dura lengthen more rapidly than the neural tube/spinal cord ,spinal cord stops and spinal nerves have to run down

Spinal nerves run obliquely from their origin to corresponding level
Large region of vertebral column with no spinal cord

Question 12

Cauda equina

Answer 12

Nerve fibers below the terminal end of the spinal cord

Can access to cerebrospinal fluid within vertebral column and inject anaesthia without affecting spinal cord

Question 13

Where does spinal cord terminate

Where does dural sac and subarchnoid space terminate

Answer 13

Spinal cord l2-l3

s2

Question 14

What is the filum terminale

Answer 14

Below l2-l3
Threadlike extension of the piwqqqa mater forms the filum terminale
Attached to the periosteum of the first coccygeal vertebra and marks the tract of regression of spinal cord

Question 15

What does the prosencephalon give rise to

ONLY ONCE ANTERIOR neuropore has closed

Answer 15

Forebrain
Telencephalon and diencephalon
Secondary vesicles - cerebrum , hypothalamus

Question 16

What does the mesencephalon give rise to

Answer 16

Midbrain
Mesencephalon
secondary vesicles - mid brain

Question 17

What does the rhombencephalon give rise to

Answer 17

Hindbrain
Metencephalon and myelencephalon
secondary- pons, cerebellum,

Question 18

Ventricular system in the brain formation

Answer 18

spaces within neural tube
Either side: from superior to inferior
Lateral ventricles, third ventricles, aqueduct
4th ventricle

Question 19

Cortical development - synapses and prunation

Answer 19

Synapses form fastest at 2-3 years old,

prunation/elimination at birth of nuerones

Question 20

3 meninges of the brain

Answer 20

Dura mater 
subdural space 
Arachnoid mater 
subarachnoid space 
Pia mater
BRain

Question 21

DURA MATER - 2 layers

Answer 21

Thickest

Superficial- endosteal layer
Deep- meningeal, continuous with dura of spinal cord

2 layers close together except for areas where meningeal layer dips down into brain fissures

Question 22

Falx cerbri

Answer 22

Layer of dura meter
Throuhg hemisphere
Vertical fold
Longitudinal fissure

Question 23

tentorium cerebelli

Answer 23

fold lying above the cerebellum and below the cerebrum

roofs over the posterior cranial fossa, opening (tentorial notch )remains to allow the midbrain to pass through

Question 24

Space occupying legion e.g. tumour

Answer 24

Dura is tough and immovable - brain may be pressed against tentorial notch

Question 25

ARACHNOID mater

Answer 25

Seperated from dura by subdural space and seperated from pia by subarachnoid ( CSF) Blood vessels and cranial nerves lie in subarachnoid space Arachnoid bridges over sulci ( grooves) of brain Arachnoid projects through dura into venous sinuses( arachnoid villi forming arachnoid granulations) in some places

Question 26

ARACHNOID VILLI

Answer 26

One way valves | allow CSF to drain into sinuses and then venous system

Question 27

Pia mater

Answer 27

thinnest closesly follows brain surface, extends down to sulci Cerebral arteries entering brain have covering of pia mater

Question 28

Headache - how is it detected

Answer 28

brain itself has NO pain receptors | Stretching/irritation of meninges or blood vessels causes headache

Question 29

Bacterial meninigitis

Answer 29

Inflammation Build up of fluid ( cerebral oedema) and increase in internal pressure = reduced blood supply Diagnosis by CSF - high white cells, high protein, low glucose

Question 30

What fills the ventricle system

Answer 30

CSF- ultrafiltrate of blood

Question 31

How does CSF leak

Answer 31

From 4th ventricle via 2 apertures - median and lateral | goes into subarachnoid space

Question 32

Function of CSF

Answer 32

Removes waste products Transports signalling molecules Renders the brain buoyant Supports, cushions and evenly distributes pressure on teh brain flows all around brain, at arachnoid granulations at TOP - CSF absorbed into SSS

Question 33

How does CSF get secreted

Answer 33

ACTIVELY by choroid plexus tissue

Question 34

Choroid plexus

Answer 34

Network of capillaries seperated from ventricles by choroid epihtelial cells

Question 35

Hydrocephalus

Answer 35

Because CSF is continuously poduced ,blockages in circulation, drainage or excess production cause increase in intracranial pressure - occur at interventricular foramen and cerebral aqueduct - new born = ventricular and skull dilation - adults - cranial cavity is closed , increase in cranial pressure headaches etc

Question 36

How to relieve cranial pressure

Answer 36

Shunt to remove excess fluid | Blockage can be caused by tumour - removing tumor relieves pressure

Question 37

Blood brain barrier

Answer 37

Tight junctions between epithelial cells | Atrocytes on brain side- regulate blood flow , close connections with basement membrane of epihtelial cells

Question 38

How do substances cross blood brain barrier

Answer 38

Water soluble - straight through paracellular Lipid soluble - transcellular lipophilic pathway Transport proteins Receptor mediated transycotsis , insulin Absorpitive transcytosis - albumin

Question 39

CSF from subarachnoid to saggital sinus

Answer 39

The CSF from the subarachnoid space is eventually reabsorbed through outpouchings into the superior sagittal sinus (SSS) known as the arachnoid granulations.