Topography of the brain

Question 1

What embryological layer does the nervous system form from?

Answer 1

Ectoderm

Question 2

What happens in neurological development at day 20?

Answer 2

1. Neuroectoderm receives inductive signals from notochord in mesoderm causing cells to thicken and form neural plate.
2. Lateral margins of neural plate fold inwards to form neural tube

Question 3

What happens in neurological development at day 24?

Answer 3

Tube thickens and neural crest cells migrate into periphery and differentiate into:

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

Question 4

At day 24 of development what do the following layers begin to become?

1. mantle layer
2. ependymal layer
3. lumen

Answer 4

1. becomes brain parenchyma (spinal cord)
2. lines ventricles of NS
3. becomes ventricles and central canal

Question 5

How does Anencephaly occur?

Answer 5

failure of anterior neuropore to close- forebrain herniates. fatal.

Question 6

How does Spina bifida occur?

Answer 6

failure of posterior neural tube to close.

Question 7

What are the two types of spina bifida?

Answer 7

Spina bifida occulta: hidden, vertebral arch defect only

Spina bifida cystica: meninges projects out posteriorly

Question 8

Name the 3 primary brain vesicles

Answer 8

1. Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)

Question 9

Name the secondary brain vesicles.

Answer 9

Prosencephalon - Telencephalon & Diencephalon
Mesencephalon-
Rhombencephalon- myelencephalon & metencephalon

Question 10

What do the secondary vesicles develop into?

Answer 10

Telencephalon: cerebral hemispheres 
Diencephalon: thalamus and hypothalamus 
Mesencephalon: midbrain 
Myelencephalon: medulla
Metencephalon: cerebellum & pons

Question 11

What are the main components of the Telencephalon?

Answer 11

Cerebral hemispheres
Parts of limbic system
Basal Ganglia

Question 12

What are the names of the lobes in which the cerebral hemispheres are divided into?

Answer 12

Parietal
Temporal
Frontal
Occipital

Question 13

What is the cerebral cortex?

Answer 13

Outer layer of the cerebral hemispheres, folded to form gyri and sulci

Question 14

What are the main sulci and gyrus you need to know?

Answer 14

Central sulcus: dividing frontal and parietal lobes
Precentral gyrus: motor (in frontal lobe)
Postcentral gyrus: sensory (in parietal lobe)
Lateral sulcus: dividing parietal and temporal lobes

Question 15

What are the sensory functional areas of the cerebral cortex?

Answer 15

Somatosensory cortex (parietal)
Visual cortex (occipital) 
Auditory cortex (temporal) 
Olfactory cortex (temporal) 
Gustatory cortex (temporal- hidden)

Question 16

What are the motor functional areas of the cerebral cortex?

Answer 16

Primary motor cortex- movement (frontal)

Motor speech area of Brocca (frontal)

Question 17

Describe the corpus callosum

Answer 17

White matter tract linking cerebral hemispheres.

Contains deep brain structures forming neural pathways of limbic system and basal ganglia

Question 18

What are the main components of the limbic system?

Answer 18

Fornix- telencephalon
Cingulate cortex- telencephalon
thalamus- diencephalon
hypothalamus- diencephalon
mamillary bodies- diencephalon
amygdala- telencephalon
hippocampus- hippocampus

Question 19

What does the fornix (white matter tract) connect?

Answer 19

Hippocampus and mamillary bodies.

Question 20

What are the basal ganglia?

Answer 20

Interconnected nuclei at base of the forebrain

Question 21

What are the basal ganglia made up of?

Answer 21

Corpus striatum: 2 nuclei forming basal ganglia are lentiform nucleus (split into putamen (outer) and globus pallidus (inner)) and caudate nucleus

Question 22

Describe the shape and positioning of the basal ganglia

Answer 22

Caudate- C shaped. sits in wall of lateral ventricle
Lentiform- lens shaped
Lentiform nucleus sits lateral to caudate nucleus
the limbic system is medial to lentiform & caudate nuclei

Question 23

What are the capsules in the telencephalon?

Answer 23

The internal capsule forms the major white matter tract connecting the cortex to the brainstem. Also forms the internal wall of the lentiform nucleus
The external capsule forms the external wall of the lentiform nucleus

Question 24

What are the 2 components of the diencephalon?

Answer 24

1. Thalamus

2. Hypothalamus

Question 25

Describe the structure and function of the thalamus

Answer 25

Paired structure connected by interthalamic region relays sensory information to the cortex involved with voluntary movement, personality & consciousness

Question 26

Describe the structure and function of the hypothalamus

Answer 26

positioned inferiorly to thalamus. Sits between optic chiasm (CN2) and mamillary bodies. involved in homeostasis, coordinates ANS and endocrine responses. Involved in thermoregulation, feeding, drinking, circadian rhythms.

Question 27

What structure connects pituitary gland to hypothalamus?

Answer 27

Infundibulum

Question 28

What parts of the brain make up the brain stem?

Answer 28

Pons- Rhombencephalon Medulla- Rhombencephalon Midbrain- Mesencephalon

Question 29

What are the components of the midbrain?

Answer 29

Cerebral peduncles (feet of brain): white matter tracts connecting pons with diencephalon Superior colliculus: eye movements Inferior colliculus: auditory. Substantial nigra: dopamingeric neurons, part of basal ganglia Red nucleus: motor coordination- relay between cortex and cerebellum

Question 30

What is the function of the pons?

Answer 30

Relays information to the cerebellum

Question 31

What are the components of the pons?

Answer 31

Middle cerebellar peduncles- white matter tracts linking brain stem with cerebellum Reticular formation- nuclei concerned with sleep, motor control

Question 32

What are the components of the medulla oblangata?

Answer 32

Pyramid: corticospinal tract- main voluntary motor pathway Olive: formed by olivary nuclei- motor relay to cerebellum Cuneate tubercle and gracile tubercle- nuclei form part of ascending tract

Question 33

What is the function of the medulla oblangata?

Answer 33

contains nuclei that are important in controlling respiration and the cardiovascular system

Question 34

Describe the structure of the cerebellum

Answer 34

Posterior to brainstem Outer grey matter and underlying white matter 2 cerebellar hemispheres divided into 3 lobes contains nuclei

Question 35

What are the main functions of the cerebellum?

Answer 35

Control of posture Coordinating and planning limb movements Control of eye movements

Question 36

Name the 3 lobes of the cerebellum and what they control

Answer 36

Anterior lobe - Posture Floccculondular lobe- Eye movement Posterior lobe- Fine motor movement

Question 37

How is the cerebellum connected to the brainstem?

Answer 37

Cerebellar peduncles (as part of pons)