BIOC32H3 Lecture Notes - Lecture 9: Lumbar Puncture, Choroid Plexus, Subarachnoid Space
BIOC32
LECTURE 9
The Central Nervous System (1)
The Nervous System
● Enteric → gut
Evolution of the Brain
● In jelly fish the nerve net functions together
to co-ordinate movement
● Flat worms = simple nervous system. Nerve
cell bodies restricted to the head.
● Annelids and segmented worms have
clusters of nerve cells (ganglia) through the
body
○ Allows functions equivalent to
spinal reflexes in humans to be
carried out
● In vertebrates the forebrain is more complex
e.g structures like cortex and cerebellum
● Animals increase in complexity and
specialisation as move up phylogenetic tree
○ CNS more complex in humans than
other animals
○ Forebrain is larger
■ Has folds to increase
surface area
Cortex Increases in Size in Higher Mammals
● Area at bottom is below the cortex
● Subcortex of animals and humans are
similar so it’s useful to study them
● Human cortex is the most complex part of
the brain
Anatomical Terminology
● Ventral moves up to become rostral
BIOC32
LECTURE 9
Development of the Nervous System
● Neural plate
○ Region in the embryo that forms the
CNS
Embryonic Day 20: Neural plate Cells Migrate to
Midline
● cells migration elevates the neural crest and
depends the neural groove
● 3 weeks post generation of embryonic cell
○ See development of neural plate
Embryonic Day 23: Neural Tube Formation
●Lumen forms the central cavity (ventricles) of
the CNS
●Lining of lumen becomes gap junction cells
and neural stem cells
●Outer layers become neurons and glia
(central nervous system (CNS))
●Neural crest becomes sensory and motor
neurons of (peripheral nervous system
(PNS))
● Outer layers become the actual neurons and
glia
Embryonic Week 4: The Anterior Neural Tube Forms
Specialized Regions of the Brain
● At week 4 cerebrum (cortex) is similar in size
to other brain regions
Embryonic Week 6: 7 Major Regions of CNS Formed
Embryonic Week 11
BIOC32
LECTURE 9
● Week 11: Growth of cerebrum (cortex)
accelerates
● At birth the cerebrum surrounds the
diencephalon, midbrain and pons
● Cranial nerves: Carry information to and
from brain for entire body
Which of the Following is NOT associated with
signalling downstream of the G protein Gs?
A. cAMP
B. Adenylyl cyclase
C. Phospholipase C
D. Protein kinase A
1. Bone Protects the Central Nervous
System (CNS)
● 3 protective layers surround the brain:
1. Bone
2. Connective tissue
3. Fluid
● Bone
○ Forms strong protective casing
around the CNS
○ Brain is encased in bony skull or
cranium
○ Spinal cord runs through vertebral
column
2. Meninges (connective tissue) support
and protect the CNS
● 3 layers:
1. Dura mater (thickest). Contains veins that
drain blood through sinuses (cavities)
2. Arachnoid mater (lose)
3. Pia mater (thin). Tightly associated with the
brain. Contains arteries that supply
● Very elastic ; strong
blood to the brain.
● Beneath pia mater is EC fluid that bathes
neurons
3. Cerebrospinal Fluid (CSF) cushions the
CNS
Document Summary
Subcortex of animals and humans are similar so it"s useful to study them. Human cortex is the most complex part of the brain. In jelly fish the nerve net functions together to co-ordinate movement. Annelids and segmented worms have clusters of nerve cells (ganglia) through the body. Allows functions equivalent to spinal reflexes in humans to be carried out. In vertebrates the forebrain is more complex e. g structures like cortex and cerebellum. Animals increase in complexity and specialisation as move up phylogenetic tree. Cns more complex in humans than other animals. Lining of lumen becomes gap junction cells and neural stem cells. Neural crest becomes sensory and motor (central nervous system (cns)) neurons of (peripheral nervous system (pns)) Outer layers become the actual neurons and glia. Embryonic week 4: the anterior neural tube forms. Region in the embryo that forms the. Embryonic day 20: neural plate cells migrate to.
