Transcript Ch 3 lec 1 - Play Psych Mun

CHAPTER 3
Structure of the Nervous System
Directions in the Nervous System
 Anterior/Rostral
= Front
 Posterior/Caudal = Back
 Dorsal = Top
 Ventral = Bottom
 Lateral = Toward the side
 Medial = Toward the midline
 Ipsilateral= Same side
 Contralateral= Opposite side
Fig. 3.1
Coronal
Fig. 3.2
Brain Slices and Planes
Coronal *Cross Section or *Frontal Section
Transverse section at right angles to the neuraxis.
Sagittal
Fig. 3.2
Brain Slices and Planes
Sagittal Section
•
•
Section parallel to neuraxis and perpendicular to the ground.
Midsagittal Plane – special type of sagittal section through the
corpus callosum separating the hemispheres.
Horizontal
Fig. 3.2
Brain Slices and Planes
Horizontal Section
Section made through the brain parallel to the ground.
Meninges
The MENINGES

Meninges

Dura Mater – tough, flexible
outermost layer.

Arachnoid Membrane – middle
layer of the meninges.


Subarachnoid Space – space
between arachnoid membrane and
pia mater filled with CSF.
Pia Mater – last layer of the
meninges, which adheres to the
surface of the brain.
Figure 3.6

Figure 3.4
Obstructive
hydrocephalus
The Ventricular System

CSF surround the brain (protection)

Four ventricles (lateral-2, third and fourth connected by cerebral aqueduct)

Choroid plexus- produces CSF (125 ml/day)

Arachnoid granulations: absorb CSF
Development of the CNS


Begins around 18th
day after conception
A patch of tissue
on the dorsal
surface of the
embryo becomes
the neural plate
Development of the CNS
Neural plate folds to form the neural
groove
Figure 3.7
Development of the CNS



The neural groove then
fuses to form the neural
tube…
Walls of the neural tube
become the CNS
Neural crest becomes the
PNS
Figure 3.7
Figure 3.8
Brain Development

Early and later development of the human nervous system
Cellular Development
 Totipotent
– earliest cells have the ability to become
any type of body cell
 Stem
cells
 Multipotent
– with development, neural plate cells
are limited to becoming one of the range of mature
nervous system cells
 Progenitor
cells
Migration of Neurons

Once cells have been created through cell division in the
ventricular zone of the neural tube, they migrate

Migrating cells are immature, lacking axons and dendrites

Inside-out migration

Progenitor cells have limited capacity to replicate

First Step: Symmetrical Division


Progenitor -> progenitor
Increases the size of the ventricular zone
Figure 3.10
Second: Asymmetrical Division
•development where a progenitor cell
divides into one progenitor cell and one
brain cell

Asymmetrical division (7 weeks after conception)




First produces radial glia
Cell bodies of RG in the VZ and processes extend to the pia
Guide the migration of new neurons (neurogenesis)
Ends after 3 months
Cellular Development and Migration

Cajal-Retzius cells
 Develop
after radial
glia
 Migrate to just inside
the pia (Layer 1)
 Orderly migration:
 Build
on each
successive layer
 All end up below C-R
Anatomical Subdivisions
Anatomy Basics
Major Division
Ventricle
Subdivision
Principle Structures
Lateral
Telencephalon
Third
Diencephalon
Cerebral
aqueduct
Mesencephalon
Fourth
Metencephalon
Forebrain
Midbrain
Hindbrain
Myelencephalon
Cerebral cortex
Basal ganglia
Limbic System
Thalamus
Hypothalamus
Tectum
Tegmentum
Cerebellum
Pons
Medulla oblongata
The Forebrain
 Largest
section of the
brain, comprised of the:
 Telencephalon

Cerebral hemispheres
 Cerebral Cortex
 Limbic System
 Basal Ganglia
 Diencephalon


Thalamus
Hypothalamus
Figure 3.8
The Forebrain
– contains
most of the cerebrum.
 Telencephalon
1.
Figure 3.8
Cerebral Cortex – thin,
wrinkled layer of tissue
covering the brain
consisting of sulci (groove),
fissures (big groove), and
gyri (convolution).




Frontal Lobe
Parietal Lobe
Temporal Lobe
Occipital Lobe
Figure 3.16
The Forebrain
Figure 3.16
 Telencephalon
 Primary




cortices
Visual cortex
Auditory cortex
Somatosensory cortex
Motor cortex
 Association

Figure 3.15
cortices
Associated with all primary
cortices
Figure 3.16
Limbic System
2.
Limbic System – set of
structures involved in
learning, memory, and
emotion. Major structures
of the limbic system
include:





Limbic Cortex (cingulate!)
Hippocampus
Amygdala
Fornix
Mammillary Bodies (part of
the hypothalamus)
Figure 3.19
Basal Ganglia
3.
Basal Ganglia – set of
structures involved in
processing information for
motor movement. Major
structures of the basal
ganglia motor system
include:



Caudate Nucleus
Putamen
Globus Pallidus
Figure 3.20
Forebrain: The Diencephalon

Thalamus and
hypothalamus

Thalamus:
Dorsal diencephalon
 Two lobes connected by
the massa intermedia
 Many nuclei

LGN
 MGN
 Cerebellum->VLN-> motor

Figure 3.8
Forebrain: The Diencephalon
Hypothalamus

Below thalamus

Many nuclei


Many diverse
behaviours
Endocrine- Pituitary
Figure 3.21
Hypothalamus regulates the autonomic nervous
system, controlling the pituitary gland, and
integrating species-typical behaviors.
Hypothalamic Portal System

Endocrine system

Hormones are secreted from the hypothalamus through the
venous portal system to anterior pituitary

These stimulate hormone release from AP


Can control other glands or the hormones are the messengers
AP- ‘master gland’


Gonadotropin-releasing hormone causes the anterior pituitary gland
to secrete gonadotropic hormones, which play a role in reproductive
physiology and behavior
Hypothalamus also releases hormones in the posterior
pituitary


oxytocin - stimulates milk ejection and uterine contractions during childbirth
Vasopressin - regulates urine output by the kidneys
The Midbrain

Also known as the
mesencephalon and is
comprised of the tectum and
tegmentum.


Tectum (roof) – contains the
superior (vision) and inferior
(auditory) colliculi (singular is
colliculus).
Figure 3.8
Tegmentum (floor) – contains
the periaqueductal gray matter,
reticular formation, red nucleus,
and substantia nigra all of
which share a role in motor
movement.
Figure 3.23c and d
The Hindbrain

The Hindbrain
 Contains
both the
metencephalon
and the
myelencephalon.
Figure 3.8
The Hindbrain
– a structure
comprised of the cerebellum
and the pons.
 Metencephalon

Cerebellum – appears as a
mini brain and is involved in
motor coordination.

Pons – contains part of the
reticular formation and is
involved in sleep and arousal.
Figure 3.23
The Hindbrain
–
contains the medulla
oblongata containing
portions of the reticular
formation
 Myelencephalon
 Is
involved in basic life
functions, such as
respiration and regulation
of the cardiovascular
system.
Figure 3.23
The Central Nervous System

The Spinal Cord
 Function:
distribute motor
fibers to the effector organs
of the body (glands and
muscles) and to collect
somatosensory information
to be passed on to the brain
 Protected by the vertebral
column
 Composed
vertebrae
of 24 individual
Primary Components of the
Spinal Cord
 Spinal
Roots – a bundle of
axons surrounded by
connective tissue that occur in
pairs, which fuse and form a
spinal nerve
 Dorsal Roots – the spinal roots
that contain incoming
(afferent) sensory fibers
 Ventral Roots - the spinal
roots that contain outgoing
(efferent) motor fibers
The Peripheral Nervous System

Somatic Nervous System

Portion of the PNS comprised of the spinal nerves and
cranial nerves involved in transmitting sensory information
and controlling voluntary movement.
 Spinal Nerves


Cranial Nerves


Peripheral nerves attached to the spinal cord.
Set of 12 motor and/or sensory nerves attached to the
ventral surface of the brain.
The Autonomic Nervous System
 Portion of the PNS concerned with the regulation of smooth
muscle, cardiac muscle, and glands
The Autonomic
Nervous System
 Sympathetic
Division of the
ANS
 Nervous
system components
involved in arousal and
preparing the body for the
expenditure of energy.

‘Fight or flight’
 Parasympathetic
Division of
the ANS
 Nervous
system components
involved in relaxing the body,
often competing with those of
the sympathetic division.

‘rest and digest’