Lecture 8 NS - Organisation of CNS 2

Question 1

What is the structure of the brain?

Answer 1

Question 2

What are the functions of the brainstem?

Answer 2

Controls vital functions -> cardio and resp, cranial nerves provide sensory and motor innervation to the head, ascending and descending pathways connect the spinal cord with the forebrain (as conduit)

Question 3

Where do the cranial nerves innervate?

Answer 3

Facial area

Question 4

What is the reticular activating system?

Answer 4

Controls level of consciousness -> ^ levels = ^ conciousness

Question 5

What are the functions of the cerebellum?

Answer 5

Coordinates movement -> monitors immediate area and modifies movement; and is involved in learning motor skills

Question 6

What are the functions of the diencephalon?

Answer 6

Contains several nuclei with different functions -> Thalamus: acts as relay station for the cerebral cortex; hypothalamus: coordinates homeostatic mechanisms

Question 7

What are the functions of the cerebral hemispheres?

Answer 7

Basal ganglia [core] -> involved in control of movement; cerebral cortex [outside] -> involved in all functions; corpus callosum -> interconnects corresponding parts of 2 hemispheres across midline

Question 8

What are sulci?

Answer 8

Crevices between folds in cortex

Question 9

How are the cortical lobes separated?

Answer 9

By the sulci:

Question 10

What does each sulci separate?

Answer 10

Central sulci -> frontal/parietal. Parieto-occipital -> parietal/occipital Lateral sulcus -> Frontal/temporal

Question 11

What are the different functional cortical areas?

Answer 11

MOTOR: Top -> lower limb; bottom -> head so little man lying up and down. SENSORY: Top -> lower limb, bottom -> head, so another little man. Primary auditory cortex -> for hearing, visual cortex for seeing. White areas are for learning, decision making -> association

Question 12

What are Wernicke’s and Broca’s areas used for?

Answer 12

Wernicke’s understanding language and comprehension; Broca’s for forming speech (tend to be dominant in left hemisphere)

Question 13

What is contained in the ventricular system?

Answer 13

CSF

Question 14

What is the lateral ventrical associated with?

Answer 14

The middle of the lobes -> communicate with the 3rd ventricle

Question 15

What is the third ventricle associated with?

Answer 15

Bisects the diencephalon

Question 16

What does the aqueduct go through?

Answer 16

Goes through the midbrain

Question 17

What does the 4th ventricle go through?

Answer 17

Through the pons

Question 18

What does the central canal go through?

Answer 18

Goes through the medulla, which then continues into the spinal cord

Question 19

What does the choroid plexus do and where is it located?

Answer 19

Inside the ventricles -> vascular gland which filters blood and changes the ionic content of blood and produces CSF

Question 20

What does the CSF in the meninges do?

Answer 20

Protects the brain from bumping into the skull

Question 21

Where does the CSF flow from?

Answer 21

Circulates through ventricular system and subarachnoid space between meninges

Question 22

How is CSF reabsorbed from the brain?

Answer 22

Reabsorbed via arachnoid villi into venous sinuses

Question 23

What is CSF?

Answer 23

Secreted by choroid plexus in ventricles, differs from blood in cellular and ionic content

Question 24

What are the three membranes from outer to inner present in between the skull and the brain?

Answer 24

Dura mater - very tough connective tissue membrane, stuck onto inside of bone; Arachnoid mater - much finer membrane; Pia membrane - attached to surface of cortex, very thin

Question 25

What structure lies in the anterior cranial fossa?

Answer 25

Frontal lobe of cerebral hemisphere

Question 26

What structure lies in the middle cranial fossa?

Answer 26

Temporal lobe of cerebral hemisphere

Question 27

What structure lies in the posterior cranial fossa?

Answer 27

Cerebellum

Question 28

What structure lies directly above the body of the sphenoid bone?

Answer 28

Hypothalamus

Question 29

What structure passes through the foramen magnum?

Answer 29

Medulla

Question 30

What part of the ventricular system relates to the cerebral hemisphere?

Answer 30

Lateral ventricle

Question 31

What part of the ventricular system relates to the diencephalon?

Answer 31

Third ventricle

Question 32

What part of the ventricular system relates to the midbrain?

Answer 32

Aqueduct

Question 33

What part of the ventricular system relates to the pons and medulla?

Answer 33

Fourth ventricle

Question 34

What is the function of the dorsal and ventral horn?

Answer 34

Ventral: contains motoneurone cell bodies. Dorsal: contains interneurones which receive sensory information from the body

Question 35

How does the flow of information work in the dorsal and ventral horn?

Answer 35

Towards the spinal cord in dorsal root and away from spinal cord in ventral root and both ways in the spinal nerve

Question 36

How does the composition of CSF differ from blood?

Answer 36

Normally contains few cells, much less protein, reduced concentration of K+ and Ca2+, higher concentration of Mg2+ and Cl-

Question 37

What are the 2 main types of hydrocephalus and their causes?

Answer 37

Communicating (4 ventricles) and non-communicating (not all ventricles)

Question 38

What are the causes of communicating hydrocephalus?

Answer 38

Block in CSF absorption/flow over brain surface caused by: meningitis, head injury, congenital, haemorrhage (sub-arachnoid)

Question 39

What are the causes of non-communicating hydrocephalus?

Answer 39

Block in ventricular system caused by: aqueduct stenosis, ventricular tumours, paraventricular tumours

Question 40

What are main signs and symptoms of hydrocephalus?

Answer 40

Headache, Drowsiness, Blackouts, Raised intracranial pressure, Increased head circumference (in child)

Question 41

What are epidural/extradural haemorrhages?

Answer 41

Usually due to damaged meningeal artery between skull and the dura after head trauma

Question 42

What are subdural haemorrhages?

Answer 42

Usually due to a damaged vein between the dura and arachnoid membrane

Question 43

How can you distinguish between an epidural and subdural haemorrhage?

Answer 43

The first symptoms (headache, drowsiness, vomiting or seizure) are likely to arise promptly after arterial bleeding in an epidural haemorrhage whereas symptoms may be delayed by hours or days after venous bleeding in a subdural haemorrhage. -\> confirm with imaging

Question 44

What are the structures usually infected in meningitis?

Answer 44

Pia mater and subarachnoid space, with some spread to the upper layers of the cortex in severe cases.

Question 45

What is the structure of the meninges?

Answer 45