NS - 4 (Brain)

Question 1

Discuss the ventricles of the brain with reference to

• origin
• lateral, 3rd And 4th

Answer 1

Origin

• neural tube enclosed by neurocoel
• neurocoel form chambers lined w/ ependyma

Lateral

• in each CH
• Sep by median partition = septum pellucidum

3rd Ven

• Ven of diencephalon
• comm w/ LV via intraVentricular Foramen of Munro

4th Ven
- connect w/ 3rd Ven via cerebral aqueduct

Question 2

Discuss how blood is supplied and removed by brain

Answer 2

Supply by Int carotid + Vertebral artery

Removed from Dural sinus by int jugular vein

Question 3

Discuss 4 ways the brain is protected

Answer 3

CSF

• choroid plexus
• in subarachnoid space
• > arachnoid granulation is a cluster of villi that absorb CSF into venous circ

Meninges - DAP

Bones

Biochemical isolation - Blood brain barrier by astrocytes that release chems

Question 4

Describe the flow of CSF

Answer 4

Cp -> LV -> Foramen Munro -> 3v -> CA -> 4v -> Foramen luschka -> SAS -> Arachnoid villi

Question 5

Give the function for each of the regions of the brain

• cerebrum (5)
• basal nuclei (6)
• MO
• Pons
• Cerebellum
• midbrain
• thalamus
• hypothalamus
• lymbic system
• diencephalon

Answer 5

cerebrum

• ch receive sense, sensory motor
• correspondence b/w functions and region of CC not precise
• White matter
• > association fibres either Arcuate (connects Gyri) or Longitudinal (connects frontal lobes)
• > Commisural fibres either Ant. Commisural or corpus Callosum
• > Projection fibres pass diencephalon and link CC w/ diencephalon

basal nuclei (subconscious thought + learned movements )

• masses of grey matter
• 6 functions
• > subconscious skeletal muscle control
• > alter compound via feedback loop
• > info from integration centre
• > lateral processes in nuclei
• > nuclei project to cc
• > Substantia nigra inhibit activity (dopamine )
• 4 parts
• > amygdaloid body = ant. Tail of caudate nucleus
• > corpus striatum = Corpus striatum + lentiform nucleus
• > lentiform nucleus= medial globus pallidus + lateral globus pallidus
• > Caudate nucleus = follows lateral vent., slender curved tail, large head

MO (coordinate autonomic reflexes + control visceral functions

• comm w/ brain and spinal cord via Tracts
• has 3 groups of nuclei
  -> Autonomic (Reticular fibres)= Reg vital functions
  -> sensory/motor = provide commands
  -> relay (3 stations)
  ~ nucleus Gracilis = pass somatic sense info to Thalamus
  ~ Solitary nucleus = receive visceral sensory info via SC and cranial nerves
  ~ Olivary nucleus = relay info about somatic motor commands to CC

Pons

• Sensory and motor nuclei
• nuclei w/ resp are part of Reticular formation
• nuclei relay info to and from Cerebellum
• ascend , descend and transverse tracts
• > transverse fibres link nuclei w/ opp cerebral hemisphere

Cerebellum (postural muscles and conscious + unconscious movement)

• 5 main structures
  -> Vermis = sep CH
  -> flocculonodular lobe below 4th ven
  -> Purkinje cells = receive synapse input
  -> Arbour vitae = internal white matter relay to Purkinje cells
  -> 3 peduncles
  ~ Sup = link cerebrum w/ Midbrain
  ~ mid = connect cerebral hemispheres w/ pons
  ~ Inf = allow comm b/w cerebellum and MO

thalamus (final relay station = relay b/w basal nuclei and cerbral cortex)

• filter small portions
• 5 thalamic Nuclei groups
• > lateral group = affect emotional states
• > post. Group = (pulvinar, Lat Geniculate, Medial Geniculate nucleus)
• > Vent. Group = relay from Basal Nuclei to Supplementary Motor Area, info about proprioception (pain and touch)
• > Medial group = awareness, connect hypothalamus w/ frontal lobe
• > Ant. Group = lymbic system, emotional state and motivation

hypothalamus = 8 functions C(4)P(2)R Stat!

• circadian rhythm
• coordination vol and autonomic functions
• coordination activities
• control autonomic functions
• provide subconscious control
• produce emotional and behavior
• reg body temp
• secrete hormones (ADH and oxytocin)

limbic system

• 5 parts
• > amygdaloid body
• > lymbic lobe
• > Fornix
• > ant. Nucleus of thalamus
• > reticular formation

diencephalon = integrates sensory info w/ motor commands

• thalamus, Epithalamus, hypothalamus
• pineal gland = secrete melatonin

Question 6

List and describe the 3 primary and 5 secondary embryological dev stages, and list the part of the brain they develop into

Answer 6

3 primary

• prosencephalon -> telencephalon (cerebrum)
• > diencephalon (thalamus, hypothalamus, Epithalamus)
• mesencephalon -> midbrain
• rhombencephalon -> mesencephalon (pons)
• > myelencephalon (medulla oblongata)

5 secondary
- telen (cerebrum -> LV)

• diencephalon (3rd Ven)
• mesen (midbrain -> cerebral aqueduct )
• metencephalon (cerebellum and pons -> 4th Ven)
• myelencephalon (medulla oblongata -> 4th Ven)