NSSB AP TBL 2.5 - Nervous System and Brainstem

What structure is responsible for smell?

CN I (Olfactory nerve)

Where does CN II originate?

Diencephalon

Which cranial nerve innervates the superior oblique muscle?

CN IV (Trochlear)

Which cranial nerve emerges dorsally from the brainstem?

CN IV (Trochlear)

Which nerve carries sensation from the face?

CN V (Trigeminal)

Which cranial nerve abducts the eye?

CN VI (Abducens)

Which nerve provides taste to the anterior 2/3 of the tongue?

CN VII (Facial)

Which nerve controls hearing and balance?

CN VIII (Vestibulocochlear)

Which nerve provides taste to the posterior 1/3 of the tongue?

CN IX (Glossopharyngeal)

Which cranial nerve provides major parasympathetic output to thoracic organs?

CN X (Vagus)

Which nerve innervates the sternocleidomastoid and trapezius muscles?

CN XI (Accessory)

Which nerve controls tongue movements?

CN XII (Hypoglossal)

What creates the facial colliculus on the dorsal pons?

CN VII fibres looping over CN VI nucleus

Which cranial nerve nucleus lies beneath the facial colliculus?

CN VI nucleus

What cells form the neural plate?

Thickened ectodermal cells

What does the neural plate give rise to?

The entire central nervous system

What do neural folds become after fusion?

The neural tube

What cells migrate from the edges of the neural folds?

Neural crest cells

What does the neural crest form?

PNS structures (ganglia, Schwann cells, melanocytes)

What does the basal plate develop into?

Motor neurons in the ventral horn

What does the alar plate develop into?

Sensory neurons in the dorsal horn

What condition results when vertebral arches fail to fuse but neural tissue is normal?

Spina bifida occulta

What is a meningocoele?

Herniation of meninges only

What is a meningomyelocoele?

Herniation of meninges and neural tissue

What is rachischisis?

Failure of neural folds to fuse, leaving neural tissue exposed

Which brainstem region contains the red nucleus?

Midbrain

What motor tract is associated with the red nucleus?

Rubrospinal tract

What is the function of the rubrospinal tract?

Modulation of limb flexor tone

Which brainstem region receives sensory and motor input from the cortex?

Pons

Which brainstem region contains respiratory control centres?

Medulla

Which brainstem structure is essential for consciousness and arousal?

Reticular formation

Which ventricle lies between the pons and cerebellum?

Fourth ventricle

Which opening allows CSF to exit from the fourth ventricle medially?

Foramen of Magendie

Which openings allow CSF to exit the fourth ventricle laterally?

Foramina of Luschka

Where is CSF produced?

Choroid plexus

What type of cells line the ventricles?

Ependymal cells

Where does CSF drain into the venous system?

Arachnoid granulations

Into which venous sinus does CSF primarily drain?

Superior sagittal sinus

What is the Monro–Kellie doctrine?

Brain + blood + CSF volumes remain constant in a rigid skull

What happens if brain tissue volume increases?

CSF or blood volume must decrease to maintain ICP

What condition results from obstruction of CSF flow?

Non-communicating hydrocephalus

What condition results from impaired CSF absorption?

Communicating hydrocephalus

What is hydrocephalus ex vacuo caused by?

Cerebral atrophy with compensatory ventricular enlargement

What is the protein level in normal CSF relative to blood?

Significantly lower

How does bacterial meningitis alter CSF glucose?

Decreases it

How does bacterial meningitis alter CSF protein?

Increases it

How does bacterial meningitis alter CSF cell counts?

Neutrophil predominance

What is the dura mater composed of?

Periosteal and meningeal layers

What lies between the two layers of dura?

Dural venous sinuses

What forms the falx cerebri?

Infolding of the meningeal dura

What type of membrane is the arachnoid mater?

Avascular connective tissue

What spans between arachnoid and pia mater?

Arachnoid trabeculae

What fills the subarachnoid space?

CSF and cerebral vessels

Which meningeal layer is tightly adherent to brain surface?

Pia mater

What space contains bridging veins?

Subdural space

A rupture of bridging veins results in what?

Subdural hematoma

A rupture of the middle meningeal artery results in what?

Epidural hematoma

What symptom is caused by meningeal irritation?

Neck stiffness (nuchal rigidity)

What clinical sign involves knee flexion resistance on hip flexion?

Kernig’s sign

What type of rash is characteristic of meningococcal meningitis?

Non-blanching petechial/purpuric rash

What is the most common cause of viral meningitis?

Enteroviruses

What is a key symptom of meningitis?

Photophobia

What cells maintain blood–brain barrier integrity?

Astrocytes

What junctions between endothelial cells form the BBB?

Tight junctions

Which molecules cross the BBB most easily?

Lipophilic molecules

What allows glucose to cross the BBB?

GLUT transporters

What effect does inflammation have on BBB permeability?

It increases permeability

Which brain regions lack a BBB?

Circumventricular organs

What is the key function of the BBB?

Protect and stabilise CNS environment

What part of the ventricular system is most prone to blockage?

Cerebral aqueduct

What part of the brainstem contains the nuclei for CN IX, X, and XII?

Medulla

Which brainstem structure is essential for respiratory rhythm generation?

Medulla

What connects the third and fourth ventricles?

Cerebral aqueduct

What connects the lateral ventricles to the third ventricle?

Interventricular foramina (of Monro)

What structure anchors blood vessels to the brain surface?

Pia mater

What lines the subarachnoid space?

Arachnoid on top, pia on bottom

Which meningeal layer contains pain fibres and contributes to headaches?

Dura mater

Which structure reabsorbs CSF into venous blood?

Arachnoid villi

What increases CSF flow into arachnoid granulations?

Increased CSF pressure

What is the main difference between communicating and non-communicating hydrocephalus?

Whether CSF pathways are open or obstructed

What are the three components of intracranial volume in the Monro–Kellie doctrine?

Brain, CSF, and blood

What is the effect of a growing tumour on intracranial dynamics?

Displaces CSF and venous blood

What is the pia-arachnoid complex called?

Leptomeninges

Which meninges are involved in meningitis?

Arachnoid and pia

What symptom is associated with raised intracranial pressure?

Headache

What is the key function of ependymal cells?

CSF circulation and lining ventricles

What is the fourth ventricle continuous with inferiorly?

Central canal of spinal cord

What is the role of the red nucleus?

Motor coordination and flexor tone

What forms the roof of the midbrain?

Tectum

Which nerve exits between the pyramid and olive in the medulla?

CN XII (Hypoglossal)

What structure lies between the pons and medulla?

Pontomedullary junction

Which cranial nerves emerge from the pontomedullary junction?

CN VI, VII, VIII

What causes papilledema?

Increased intracranial pressure

What forms the blood–CSF barrier?

Choroid plexus epithelium

What is the composition of normal CSF?

Low protein, clear, colourless

What happens to CSF protein in viral meningitis?

Mild elevation

What happens to CSF glucose in viral meningitis?

Normal

Which meninges create cisterns filled with CSF?

Arachnoid and pia

What structure contains the arterial circle supplying the brain?

Subarachnoid space

What structure sits in the sella turcica?

Pituitary gland