H&N6 - Basics of the CNS & Anatomy of the Brain & Brainstem

Question 1

3 differences between the CNS and PNS

Structures
Regeneration
BBB

Answer 1

1. ) CNS is brainstem and spinal cord whilst PNS is spinal and peripheral nerves
2. ) CNS cannot regenerate whilst PNS can
3. ) CNS has a blood brain barrier

Question 2

Anatomical orientation of the brain and brainstem

anterior, inferior, posterior, superior

Answer 2

1. ) Brainstem
   - anterior = ventral, inferior = caudal, posterior = dorsal, superior = rostral,
2. ) Brain - development causes orientation to rotate 90 degrees anti-clockwise
   - anterior = rostral, inferior = ventral, posterior = caudal, superior = dorsal

Question 3

What are sulci, gyri, and fissures?

Answer 3

1. ) Sulcus - groove separating adjacent gyri
   - central and parieto-occipital sulci
2. ) Gyrus - fold in the brain
   - pre and post-central gyri
3. ) Fissure - large split between adjacent large areas of the brain
   - longitudinal and lateral fissure

Question 4

3 parts of the brainstem

Answer 4

1. ) Midbrain (mesencephalon) - top of brainstem
   - responsible for eye movements and reflex responses to sound and vision
   - contains cerebral peduncles which are nerve tracts running from the forebrain into the brainstem
2. ) Pons - middle, bulging part of brainstem
   - responsible for feeding and sleep
3. ) Medulla - bottom of brainstem
   - contains cardiovascular and respiratory centres
   - contains major motor pathways (medullary pyramids)

Question 6

3 features on the inferior aspect of the cerebrum

Answer 6

1. ) Optic Chiasm - where fibres in the visual system cross over
2. ) Uncus - part of temporal lobes that can herniate, compressing the midbrain
3. ) Medullary Pyramids - location of descending motor fibres (1 million axons each)

Question 7

What are the 4(5) lobes of the cerebrum

Answer 7

1. ) Frontal Lobe - cognition, motor function, speech
2. ) Parietal Lobe - sensation and spatial awareness
3. ) Temporal Lobe - memory, smell, hearing, emotional processing
4. ) Occipital Lobe - vision
5. ) Cerebellum - coordination and motor hearing

Question 7

3 features on the medial aspect of the cerebrum

Answer 7

1. ) Corpus Callosum - fibres (white matter) connecting the 2 cerebral hemispheres
2. ) Thalamus - sensory relay station projecting to sensory cortex
   - found in the diencephalon
3. ) Hypothalamus - centre for homeostasis
   - found in the diencephalon

Question 8

4 functional areas of cortex in the cerebrum

Answer 8

1. ) Primary Motor - located on the pre-central gyri , anterior to the central sulcus
2. ) Primary Somatosensory - located on the post-central gyri, posterior to the central sulcus
3. ) Primary Visual - found on posterior occipital lobe
4. ) Primary Auditory - located on temporal lobe
5. ) Primary Olfactory - uncus of the temporal lobe

Question 9

4 features of the cerebellum

Anatomical Features
Functions
Lesions
Sensitivities

Answer 9

1. ) Anatomical Features - very similar to the cerebrum
   - contains folds, 2 hemispheres made up of lobes etc.
   - peduncles connect the cerebellum to brain stem
   - also contains vermis and tonsils
2. ) Functions - coordinating voluntary motor activity:
   - speech, eye movements, limbs, and maintaining balance and posture
3. ) Ipsilateral Lesions - clinical signs manifest on the same side of the body. No decussation
4. ) Alcohol Sensitive - neurones within the cerebellum is very sensitive to the effects of alcohol

Question 10

3 features of the ventricular system in the brain and brainstem

Communications
Divisions

Answer 10

1. ) Cavity filled with CSF
2. ) Communications - with the subarachnoid space and central canal of spinal cord
3. ) Divisions - split into 2 lateral ventricles, 3rd ventricle and 4th ventricle which all communicate with each other
   - septum pellucidum separates the 2 lateral ventricles