T1L3 topography of the brain

Question 1

neurulation

Answer 1

• neuroectoderm receives signals from neurochord
• induces cells to thicken to form neural plate
• lateral edges of this fold in to make neural tube

Question 2

neurochord location

Answer 2

within mesoderm

Question 3

development of ns from:

• neural crest cells
• mantle layer
• ependymal layer
• lumen

Answer 3

neural crest cells:

1. neurons and glia of sensory and autonomic ns
2. cells of adrenal gland
3. epidermis
4. skeletal/connective tissue

mantle layer:
- becomes brain parenchyma

ependymal layer
- lines ventricles

lumen
- becomes ventricles and central canal

Question 4

neural tube defects

Answer 4

1. failure of anterior neuropore to close&raquo_space; anencephaly (fatal)
2. failure of posterior neuropore tube to close&raquo_space; spina bifida (open vertebral canal)

Question 5

development of the brain

Answer 5

expansion of cranial end of neural tube leads to 3 portions:

1. prosencephalon > forebrain
2. mesencephalon > midbrain
3. rhombencephalon > hindbrain

these are primary vesicles

Question 6

prosencephalon >

Answer 6

telencephalon > cerebral hemispheres
optic vesicles > eyes
diencephalon > thalamus/hypothalamus

these are secondary vesicles

Question 7

mesencephalon >

Answer 7

eventually develops into midbrain

Question 8

rhombencephalon >

Answer 8

metencephalon > pons/cerebellum
myelencephalon > medulla

these are secondary vesicles
see s6 x

Question 9

forebrain and brainstem contents

Answer 9

forebrain:

• cerebral hemispheres
• diencephalon

brainstem:
- midbrain (mesencephalon)

• pons (metencephalon)
• cerebellum (metencephalon)
• medulla (myelencephalon)

Question 10

grey vs white matter

Answer 10

grey- mainly neuronal cell bodies (eg cerebral cortex)white- mainly myelinated axons

Question 11

telencephalon

Answer 11

• cerebral hemispheres (frontal, occipital, temporal, parietal)
• limbic system
• basal ganglia

80% of the cortex is involved with perception of the world and cognition

see s12 for functional areas

Question 12

precentral vs postcentral sulcus

Answer 12

precentral = motor
postcentral = sensory

Question 13

corpus callosum

Answer 13

• white matter tract linking cerebral hemispheres

Question 14

deep brain structures

Answer 14

limbic system (memory and emotion)
basal ganglia (posture and voluntary movement)

Question 15

limbic system

Answer 15

spans telencephalon and diencephalon
includes:
- cingulate cortex
- fornix
- hypothalamus
- mammillary bodies
- amygdala
- hippocampus

Question 16

fornix

Answer 16

• semi-circular white tract matter connecting hippocampus and mammillary bodies

Question 17

hippocampus

Answer 17

looks like seahorse (hence the name)

- sits on floor of lateral ventricle

Question 18

basal ganglia

Answer 18

series of interconnected nuclei at base of forebrain

corpus striatum > caudate nucleus
> lentiform nucleus > putamen
> globus pallidus

lentiform is lens shaped
caudate is c shaped and sits in lateral wall of ventricle

• lentiform nucleus sits lateral to caudate nucleus

worth looking at all these slides to learn to cross sections too

Question 19

capsules

Answer 19

the internal capsule is major white matter tract
- connects cortex to brainstem

also an external capsule

Question 20

diencephalon

Answer 20

thalamus and hypothalamus
- central location

thalamus:

• relays sensory information to cortex
• voluntary movement, personality, consciousness

hypothalamus:
- inferior to thalamus
homeostasis:
- ANS and endocrine responses
- involved in thermoregulation, feeding, drinking, circadian rhythms
- receives input from limbic system
- pineal and pituitary gland

Question 21

brainstem contains

Answer 21

• cranial nerve nuclei
• respiratory and cardiovascular centres
• vomiting
• nuclei involved with motor control and sleep
• white matter tracts

Question 22

midbrain

Answer 22

• cerebral peduncles (white matter tracts connecting pons with diencephalon)
• superior colliculus (eye movement)
• inferior colliculus (auditory)
• red nucleus (motor coordination between cortex and cerebellum)
• substantial nigra (part of basal ganglia- dopaminergic neurons)

Question 23

pons

Answer 23

relays info to cerebellum

Question 24

peduncle meanign

Answer 24

stalk like

Question 25

medulla oblongata

Answer 25

ANTERIOR
pyramid:
corticospinal tract - main voluntary motor pathway

olive:
formed of olivary nuclei
motor relay to cerebellum

POSTERIOR
cuneate and gracile tubercles (nuclei form part of ascending tract)
- important for cardio and respiratory systems

Question 26

cerebellum

Answer 26

• outer grey matter
• inner white matter
• two cerebellar hemispheres
• three lobes
• contains nuclei

functions:

• control of posture
• co-ordination and limb movements
• eye movements

connected to brainstem by cerebellar peduncles

see s33 for lobes