Topography of the brain Flashcards
NEURULATION PT 1
i) which germ layer forms the nervous system?
ii) where do neurectoderm cells recieve inductive signals from?
iii) when the NE cells thicken - what do they form?
iv) what has to happen for the neural tube to form?
v) at what day is the neural tube formed?
i) ectoderm
ii) NE cells recieve inductive signals from the notochord
iii) NE cells thicken and form the neural plate
iv) the lateral neural plate margins have to fold inwards to form the neural tube
v) neural tube is formed at embryonic day 20
NEURULATION PART 2
i) when the neural crest cell migrate to the periphery what 4 things do they form?
ii) label diagram A-E and what each layer later becomes
iiii) at what embryonic day does the neural crest migration and neural tube thickening happen?
iv) what layer does the brain parenchyma and spinal cord arise from?
i) form into 1) autonomic and sensory neurons/glia
2) cells of adrenal gland
3) epidermis
4) skeletal/connective tissue of the head
ii) A - neural crest cells (migrate to periphery and form into 4 cell types)
B - ectoderm (sits over the top)
C - mantle layer (bulk of neural tube and becomes the brain parenchyma - spinal cord)
D - Ependymal layer (becomes lining of ventricles of brain)
E - Lumen (becomes ventricles and central canal of spinal cord)
iii) embryonic day 24
NEURAL TUBE DEFECTS
i) how many out of 1000 established pregnancies do NT defects occur in?
ii) what defect is due to failure of anterior neuropore to close? is this embryonic lethal?
iii) what defect is failure of the posterior NT to close? is this embryonic lethal?
i) 1 in 1000 establish pregnancies = neural tube defects
ii) failure of ant NT to close = ancephaly (forebrain herniates out the foetus) = fatal
iii) failure of post NT to close = spina bifida = not embryonic lethal
SPINA BIFIDA
i) is the failure of which end of the neural tube to close?
ii) what % mortality is it associated with? how can this be reduced?
iii) what does it lead to?
iv) what is a) spina bifida oculta and b) spina bifida cystica?
- which one is more serious?
v) what type of spina bifida is shown in the picture?
i) failure of the posterior NT to close
ii) associated with 25% mortality and this can be reduced by taking folic acid supplement
iii) leads to an open vertebral canal
iv) a) oculta = hidden and vertebral arch defect only
b) cystica = meninges project out (meningocele which is full of CSF and spinal contents can herniate out)
- SB cystica is more serious
v) spina bifida cystica
PRIMARY BRAIN VESICLES
i) what are the three primary vesicles and what do they become?
ii) after folding the flexures are developed - what are these called? label the areas A-E on the folded brain
iii) label A-C on the primary vesicle diagram
i) three primary vesicles = prosencephalon > forebrain
mesencephalon > midbrain
rhombencephalon > hindbrain
ii) cephalic and cervical flexure
A - prosencephalon
B - mesencephalon
C - rhombencephalon
D - cephalic flexure
E - cervical flexure
iii) A = prosencephalon
B = mesencephalon
C = rhombencephalon
SECONDARY BRAIN VESICLES
i) which end expands to form the secondary vesicles?
ii) name the structures that the prosen, mesen, rhomben further differentiate into? label the diagram
iii) which flexure is developed on folding of the secondary vesicles? which structures does it develop between? label the folded diagram
i) cranial end
ii) prosen
(A1) telencephalon > cerebral hemis
(A2) optic vesicles > eyes
(A3) diencephalon > thalamus/hypothalamus
mesen
- doesnt differentiate into anything, just keeps growing
rhomben
(C1) metencephalon > pons/cerebellum
(C2) myencephalon > medulla
iii) Flexure X = pontine flexure is developed between the meten and myencephalon
ADULT BRAIN
which brain vesicles did each structure develop from?
- ceb hemispheres - telencephalon
- thalamus/hypothalamus - diencephalon
- midbrain - mesencephalon
- pons - metencephalon
- medulla - myelencephalon
GREY AND WHITE MATTER
i) what does grey matter predominantly contain? give two examples
ii) what does the white matter mainly contain?
iii) what weighted is the MRI? what colour are grey and white matter on this kind of scan?
i) grey matter contains neuronal cell bodies eg cerebral cortex and brain nuclei
ii) white matter contains myelinated axons
iii) T1 weighted (dark fluid)
GM - dark
WM - light
CEREBRAL HEMISPHERES
i) which vesicle do these arise from? which two brain areas also arise from this vesicle?
ii) what are the four lobes of the cerebrum?
iii) label the gyri and sulci on the picture A-D
i) arise from the telecephalon (basal ganglia and limbic system also arise from here)
ii) frontal, temporal, parietal, occipital
iii) A = lateral sulcus (divides temporal and parietal)
B = precentral gyrus (motor)
C = central sulcus (div frontal from parietal)
D = post central gyrus (sensory)
FUNCTIONAL AREAS OF THE CORTEX
i) what % of the brain cortex do sensory and motor areas constitute?
ii) what does the primary motor cortex control? where does it sit on the brain?
iii) what does the somatosensory cortex control? where does it sit on the brain?
iv) what lobe is the visual cortex found in?
v) what lobe do the auditory, olfactory and gustatory cortex sit in?
vi) what area does motor speech area of broca sit in?
i) 20% of brain cortex
ii) primary motor cortex = movement and sits in the precentral gyrus
iii) somatosensory controls touch, pain, proprioception and sits in the post central gyrus
iv) visual cortex is found in the occipital lobe
v) aud, olfactory and gustatory are found in the temporal lobe
vi) brocas area is in the prefrontal cortex
CORPUS CALLOSUM
i) what is it?
ii) what are the three parts of the CC from ant to posterior? where do motor anx sensory axons it?
ii) what is the nname of the white matter wiring that spreads to all different parts of the brain?
i) white matter tract linking the cerebral hemispheres
ii) genu > body > splenium
- motor axons @ genu and sensory axons @ body
iii) white matter wiring spreading into brain = corona radiata
LIMBIC SYSTEM
i) which two brain vesicles does it span?
ii) label A-E
iii) what is the fornix? what two structures does it connect?
i) spans the telencephalon and the diencephalon
ii) A - cingulate cortex
B - fornix
C - thalamus
D - hypothalamus
E - amygdala
iii) fornix is a semicirculat white matter tract that connects the hippocampus with the mamillary bodies of the hypothalamus
what is the structure labelled A?
the fornix
HIPPOCAMPUS
i) where does it sit anatomically?
ii) what is label A and B?
i) sits in the floor of the lateral ventricle
ii) A = fornix
B = hippocampus
what brain structure is highlighted on the MRI?
the hippocampus
BASAL GANGLIA PT 1
i) the BG is a series of interconnected nuclei in which part of the forebrain?
ii) what is the corpus striatum composed of? (2 nuclei)
iii) what can one of these structures be further divided into?
iv) which nucleus is lens shaped?
v) which nucleus is C shaped? where does this nucleus sit?
vi) label the nuclei A-B3
i) basal ganglia is at the base of the forebrain
ii) corpus striatum = lentiform nucleus and caudate nucleus
iii) lentiform can be subdivided into putamen and globus pallidus
iv) the lentiform nucleus is lens shaped
v) the caudate is V shaped and sits in the wall of the lateral ventricle
vi) A = lentiform nucleus
B1 = head of caudate, B2 = body of caudate, B3 = tail of caudate
BASAL GANGLIA PT 2
i) where does the lentiform nucleus sit in relation to the caudate?
ii) label A-D on the diagram
i) lentiform nucleus sits lateral to the caudate
ii) A = lentiform nucleus (cont putamen and GP)
B1 = head and body of caudate B2 = tail of caudate nucleus
C = putamen D = globus pallidus
which structure of the basal ganglia is indicated by A?
the head of the caudate nucleus (sits in the wall of the lateral ventricle)
THE CAPSULES
i) what are they?
ii) what does the internal capsule form? and what two structures does it connect?
iii) what does the internal capsule form the internal wall of?
iv) what does the external capulse form the external wall of?
v) label structures A-D
i) white matter tracts in the brain
ii) internal capsule forms the major white matter tract and it connects the cortex to the brainstem
iii) internal capsule forms the internal wall of the lentiform nucleus
iv) external capusule forms the external wall of the lentiform nucleus
v) A = internal capulse
B = external capulse
C = putamen
D = Globus pallidus
DIENCEPHALON
i) what primary brain vesicle does the diencephalon orignate from?
ii) what are the two components of the diencephalon?
iii) what position does it sit in the brain?
iv) label structures A and B on the picture
i) originates from the prosencephalon
ii) thalamus and hypothalamus
iii) sits in a central location
iv) A = thalamus
B = hypothalamus
HYPOTHALAMUS
i) where does it sit in relation to the thalamus?
ii) what two structures does it sit between?
iii) what is its main role? name three ways which it does this
iv) it controls secretions from which gland that sits below it? what connects these two structures?
v) label structures A-C
i) sits inferior to the thalamus
ii) sits between the optic chiasm and mamillary bodies
iii) main role is homeostasis
1) co-ordinates ANS and endocrine responses
2) involved in thermoreg/feed/drink/circadian rhythms
3) receieves input from limbic system
iv) controls secretions of the pituitary gland that sits below it - connected by an infundibulum
v) A = thalamus
B = hypothalamus
name structures A, B and C
what do system do these three structures make up?
A = mamillary body of hypothalamus
B = fornix
C = hippocampus
- make up the limbic system
MESENCEPHALON AND RHOMBENCEPHALON
i) what does each become in the mature brain?
ii) name structures A, B and C
i) mesencephalon > midbrain
rhombencephalon > brainstem = pons and medulla
ii) A = midbrain
B = pons
C = medulla
MIDBRAIN
i) which brain primary brain vesicle does it arise from?
ii) name the three main components of the midbrain
iii) it contains white matter tracts that connect the pons to what?
iv) what are the superior and inferior colliculi associated with and what is their function?
v) name structures A-C
i) arises from the mesencephalon
iii) colliculi, tegmentum and cerebral peduncles
iii) contains WM tracts that connect the pons to the diencephalon
iv) superior colliculus = assoc with vision and involved in eye movements (takes in info from the optic tract)
inferior colliculus = assoc with hearing and is a relay nuclei from the auditory cortex to the temporal lobe
v) A = cerebral peduncles
B = superior colliculus (vision)
C = inferior colliculus (auditory)
PONS
i) what is its primary role?
ii) what structure connects it to the cerebellum?
iii) what structure do its transverse fibres form?
iv) which nuclei does it contain that is associated with sleep and motor control?
v) name structures A and B
i) primary role is relaying information to the cerebellum
ii) conected to the cerebellum by the middle cerebellar peduncle
iii) transverse fibres of the pons form cerebellar peduncles (pontine fibres)
iv) contains the reticular formation - sleep and motor control
v) A = middle cerebellar peduncle
B = pons
MEDULLA OBLONGATA
i) which structure does it contain that contains the corticospinal tract? what is the main role of the tract?
ii) which structure is the motor relay to the cerebellum?
iii) which two tubercles form part of the ascending tract? what nuclei sits underneath these?
iv) which two important systems are controlled here?
v) label structures A-D
i) the pyramids contain the corticospinal tract which is the main voluntary motor pathway (motor info from primary motor cortex > spinal cord)
ii) motor relay to the cerebellum = olive which contains olivary nuclei
iii) gracile and cuneate tubercle - cuneate and gracile nuclei sit below these and form ascending pathways to brain
iv) control of respiration and cardiovascular system
v) A = pyramids
B = olive
C = cuneate nucleus
D = gracile nucleus
