T1 L3: Topography of the brain

Question 1

what does neurulation mean?

Answer 1

development of the brain

Question 2

describe the process of neurulation

Answer 2

• Neuroectoderm cells receive inductive signals from notochord
• Cells thicken to form neural plate
• Lateral neural plate margins fold inwards to form neural tube
• embryonic day 20

Question 3

look at slide 2 to label slide

Answer 3

how was it

Question 4

how does the nervous system develop

Answer 4

neural crest cells differentiate into:

1) Neurons and glia of the sensory and autonomic nervous systems
(2) Cells of the adrenal gland
(3) Epidermis
(4) Skeletal/connective tissue of the head

Mantle layer
- Becomes brain parenchyma

Ependymal layer
- Lines ventricles

Lumen
- Becomes ventricles + central canal

embryonic day 24

Question 5

describe some neural tube defects

Answer 5

Anencephaly (fatal)- Failure of anterior neuropore to close

Spina bifida- Failure of posterior neural tube to close

leads to open vertebral canal

Question 6

describe the difference between spina bifida occulta and spina bifida cystica

Answer 6

1) spina bifida occulta: hidden, vertebral arch defect only

2) Spina bifida cystica -meningocele = meninges projects out

Question 7

describe the primary vesicles of the brain

Answer 7

In order:

Prosencephalon = forebrain

mesencephalon= midbrain

rhombencephalon= hindbrain

Question 8

describe the secondary vesicles of the brain and what embryonic day it derives from

Answer 8

• day 36
• Telencephalon-cerebral hemispheres

optic vesicles- eyes

diencephalon = thalamus/hypothalamus

metencephalon = pons/cerebellum

myelencephalon = medulla

Question 9

go through slides 1-7 especially the diff planar views of the brain

Answer 9

how was it

Question 10

describe and identify gray and white matter (slide 8)

Answer 10

gray: mainly neuronal cell bodies (e.g. cerebral cortex, brain nuclei)

White matter - mainly myelinated axons

Question 11

describe what the telencephalon comprises of

Answer 11

Comprises the cerebral hemispheres/cerebral cortex, components of the limbic system and the basal ganglia

Question 12

describe and identify the division of the cerebral hemispheres into lobes

Answer 12

slide 10 how was it

Question 13

give some features of the cerebral CORTEX

Answer 13

Outer layer of cerebral hemispheres

Folded to form gyri and sulci

Question 14

label the precentral gyrus and postcentral gyrus as well as their main feature

Answer 14

pre- motor

post- sensory

slide 11

Question 15

what is the lateral sulcus and identify it

Answer 15

divides temporal from parietal lobe)

slide 11

Question 16

what I the majority of the cortex involved with

Answer 16

in association (perception of world) and cognition

Question 17

LABEL some functional areas of the cortex

Answer 17

• sensory: auditory,olfactory, visual, somatosensory
  motor: primary motor cortex, premotor cortex, motor speech

12

Question 18

describe the corpus callosum and label

Answer 18

13-

white matter tract linking cerebral hemispheres

Question 19

describe 2 deep brain structures

Answer 19

Limbic system
- Involved with emotion and memory

Basal ganglia:
- Involved in the control of posture and voluntary movement

Question 20

what are deep brain structures

Answer 20

-interaction of white and gray matter deep to cerebral hemispheres to form neural pathways that are interconnected

Question 21

what regions of the brain does the limbic system consist of

Answer 21

• Limbic system spans the telencephalon and diencephalon

includes: fornix, cingulate cortex, amygdala, hippocampus, (hypothalamus , mamillary bodies )

Question 22

describe the fornix

Answer 22

The fornix is a semi-circular white matter tract connecting the hippocampus with the mammillary bodies

consist of : body of fornix, mamillary body, amygdala, hippocampus

Question 23

describe the hippocampus

Answer 23

• the hippocampus looks like a sea horse

- consists of the fornix, pes (foot hippocampus) and sits in the floor of lateral ventricles

Question 24

talk through the terminology of the basal ganglia

Answer 24

Corpus striatum

- caudate nucleus, lentiform nucleus- putamen, globus pallidus

Question 25

describe the structures of the basal ganglia

Answer 25

Lentiform nucleus is lens
shaped

Caudate nucleus is C-shaped and sits in wall of lateral ventricle

Question 26

describe the basal ganglia

Answer 26

-Lentiform nucleus sits lateral to caudate nucleus

Question 27

describe the capsules

Answer 27

-internal capsule forms major white matter tract

Question 28

describe the diencephalon

Answer 28

-comprises the thalamus and hypothalamus

Question 29

describe the thalamus

Answer 29

Paired structure

• Relays sensory information to the cortex
• Involved with voluntary movement, personality and consciousness

Question 30

describe the hypothalamus

Answer 30

Inferior to thalamus

Homeostasis:
-Coordinates ANS and endocrine responses

• Involved in thermoregulation, feeding, drinking, circadian rhythms
• Receives inputs from limbic system24-25

Question 31

what do the mesencephalon and the rhombencephalon form

Answer 31

• the brainstem and cerebellum

midbrain- mesencephalon

pons & medulla- rhombencephalon

Question 32

what does the brainstem contain

Answer 32

• Cranial nerve nuclei within all three regions
• Vital respiratory and cardiovascular centres
• Vomiting centre
• Nuclei involved with motor control, sleep
• White matter tracts

Question 33

what are the main functions of the cerebellum

Answer 33

motor control:
- control of posture

• coordinating and planning limb movements
• control of eye movements

Question 34

describe the Medulla oblongata

Answer 34

Pyramid:
Corticospinal tract – main voluntary motor pathway

Olive-
Formed by olivary nuclei
Motor relay to cerebellum

1-Cuneate tubercle,Gracile tubercle
- Nuclei form part of ascending tract
(see spinal cord lecture)