the central nervous system presentation dawn part 1
TRANSCRIPT
BY,
DAWN V TOMY M.PHARM.,ASST. PROFESSOR,
DEPT. OF PHARMACOLOGY,
ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
1
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
2
INTRODUCTION
• The central nervous system (CNS) consists of the brain and spinal cord.
• The brain is encased in the skull, and protected by the cranium.
• The brainstem connects the brain to the spinal cord. Brain communicate
with the peripheral nervous system (PNS) through the spinal cord.
• The spinal cord starts from the base of the skull, continues
through the foramen magnum, lies caudally to the brain and is protected
by the vertebra and terminates at the first or second lumbar vertebra.
CENTRAL NERVOUS SYSTEM (CNS)
The brain is situated in the cranial cavity formed by the cranial and
facial bones. It is protected by the meninges. It is nourished and
cushioned by the Cerebrospinal Fluid (CSF) formed in ventricles.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
3
ANATOMY OF THE BRAIN
STRUCTURE OF THE BRAIN.
4Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
An adult brain weighs between 1.3 to 1.4 kg and has a volume of about 1200 cc.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
5
BRAIN
6
Major parts of the brain:
•Cerebrum
• Frontal lobes
• Parietal lobes
• Occipital lobes
• Temporal lobes
• Insula
•Diencephalon
•Epithalamus
•Thalamus
•Subthalamus and
•Hypothalamus
•Brainstem
• Medulla oblongata
•Pons
•Midbrain
•Cerebellum
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Major Parts of the Brain
7
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
8
• It helps to maintain homeostasis.
• Interprets sensations.
• Determines perception.
• Stores memory.
• Reasoning.
• Makes decisions.
• Coordinates muscular movements.
• Regulates visceral activities.
• Determines personality.
FUNCTIONS OF THE BRAIN.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Brain Development
9
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
BLOOD FLOW
10
Supply: Internal carotid and vertebral arteries.Return: Internal jugular veins (from head to heart)
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
BLOOD BRAIN BARRIER (BBB)
11
The endothelial cells of the braincapillaries along with thick basementmembrane and astrocytes forms tightjunctions which selectively passessubstances from blood to brain.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
CSF AND CEREBRAL VENTRICLES
12
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Ventricles and Cerebrospinal Fluid
13
• There are four (4) ventricles• The ventricles are interconnected cavitieswithin cerebral hemispheres and brain stem.• The ventricles are continuous with thecentral canal of the spinal cord.• They are filled with cerebrospinal fluid (CSF).
• The four (4) ventricles are:• Lateral ventricles (2)
• Known as the first and second ventricles
• Third ventricle• Fourth ventricle
• Interventricular foramen.• Cerebral aqueduct.
Lateral ventricle
Third ventricle
Fourth ventricle
(a)
Interventricular
foramen
Cerebral
aqueduct
To central canal
of spinal cord
Third ventricle
(b)
Cerebral
aqueduct
To central canal
of spinal cord
Fourth
ventricle
Lateral
ventricle
Interventricular
foramen
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
14
A lateral ventricle is located in each hemisphere ofthe cerebrum. Anteriorly, the lateral ventricles areseparated by a thin membrane, the septumpellucidum. The 3rd ventricle is a narrow cavity alongthe midline; superior to the hypothalamus andbetween the right and left halves of thalamus. The4th ventricle lies between the brain stem and thecerebellum. The 4th ventricle is continuous with thecentral canal of spinal cord.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
15Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Formation of CSF in the ventricles.
16
CSF is produced in the choroid plexuses which are network ofcapillaries in the walls of the ventricles.The ependymal cells that cover the capillaries formcerebrospinal fluid from the blood plasma by filtration andsecretion process.The ependymal cells joined by tight junctions in the choroidcapillaries forms the blood-cerebrospinal fluid barrierpermitting selective diffusion, thereby protecting the brainand spinal cord from potentially harmful blood-bornsubstances.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Cerebrospinal Fluid
17
•Circulates in ventricles, centralcanal of spinal cord, and thesubarachnoid space.• Completely surrounds the brainand spinal cord.• Excess or wasted CSF is absorbedby the arachnoid villi.• It is a clear fluid similar to bloodplasma.• Volume is only about 120 ml.• Nutritive and protective function.• Helps maintain stable ionconcentrations in the CNS.
Third ventricle
Fourth ventricleCerebral aqueduct
Subarachnoid space
Arachnoid mater
Dura mater
Pia mater
Pia materCentral canal of spinal cord
Subarachnoid space
Filum terminaleArachnoid mater
Dura mater
Arachnoid
granulations
Choroid plexuses
of third ventricle
Blood-filled
dural sinus
Choroid plexus of
fourth ventricle
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
18Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
THE COMPOSITION OF CSF.
19
Total volume of CSF is 80 to 150mL in anadult. It contains Glucose, Proteins, Lacticacid, Urea, Cations (Na+, K+, Ca2+ andMg2+) and Anions (Cl- and HCO3
-). It alsocontains WBCs.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
20
The CSF contributes to brain and spinal cord homeostasis in 3 ways.
1. Mechanical protection: It serves as shock absorbing medium that protects thedelicate tissues of the brain and spinal cord from impacts by not letting them hitthe bony walls of the cranial and vertebral cavities. The fluid also buoys the brainfloating it in the cranial cavity.
2. Chemical protection: Provides an optimal chemical environment for accurateneuronal signalling. Ionic composition to be maintained in homeostasis as evenslight changes in them can affect the production of action potentials andpostsynaptic potentials.
3. Circulation: CSF is a medium for exchange of nutrients and waste productsbetween the blood and nervous tissue.
FUNCTIONS OF CSF
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Meninges
21
• The meninges• Membranes of CNS• Protect the CNS• Three (3) layers:
• Dura mater• “Tough mother”• Venous sinuses• Falx
• Arachnoid mater• “Spiderweb-like”• Space contains cerebrospinal fluid (CSF)
• Pia mater• “Faithful mother”• Encapsulates blood vessels
Scalp
Cranium
Cerebrum
Cerebellum
Spinal cord
Meninges
Meninges
Cerebrum
(b)(a)
Gray matterWhite matter
Subarachnoid spaceFalx cerebri
Pia mater
Dura mater
Bone of skullSubcutaneous tissueSkin
Tentorium
cerebelli
Vertebra
Dural sinus Arachnoid
granulation
Arachnoid
mater
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
22
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
23
Protective covering of the brain:The cranium and the cranial meninges surround and protect the brain.The cranial meninges are continuous with spinal meninges. They are:1. The outer dura mater (The cranial dura mater has 2 layers and
spinal dura mater has only one layer).2. The middle arachnoid mater and3. The inner pia mater.
The space between Dura mater and arachnoid mater is known assubdural space and that between arachnoid mater and pia mater isknows as subarachnoid space which is filled with cerebrospinal fluid(CSF).
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
24
The parts of brain are separated by 3extensions of the dura mater. They are:1. The falx cerebri which separates 2
hemispheres of cerebrum.2. The falx cerebelli which separates 2
hemispheres of cerebellum and3. The tentorium cerebelli which separates
the cerebrum from the cerebellum.Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
25Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Meninges of the Spinal Cord
26
Spinal cord
Spinal cord
Pia mater
Arachnoid mater
Dura mater
Dorsal root
Dorsal root
Spinal nerve
Epidural space
(a) (b)
Ventral root
Dorsal root
ganglion
Thoracic
vertebra
Spinal
nerve
Dorsal root
ganglion
Subarachnoid space
Dorsal branch
(dorsal ramus)
Ventral branch
(ventral ramus)
Ventral root
Epidural space
Body of vertebra
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
STRUCTURE OF CEREBRUM.
27Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Structure of the Cerebrum
28
• Corpus callosum
• Connects cerebral hemispheres
(a commissure)
• Gyri
• Bumps or convolutions.
• Sulci
• Grooves in gray matter
• Central sulcus.
• Fissures
• Longitudinal: separates the
cerebral hemispheres
• Transverse: separates cerebrum
from cerebellum
• Lateral fissure (sulcus) of
Sylvius.
Central sulcus
Gyrus
Sulcus
Frontal lobeLateral fissure of sylvius
Parietal lobe
Occipital lobe
Central sulcus
Parietal lobe
Occipital lobe
(a)
(b) (c)
Parietal lobe
Central sulcus
Occipital lobeFrontal lobe
Insula
Temporal lobe
Longitudinal
fissure
Transverse
fissure
Cerebellar
hemisphere
Retracted
temporal lobe
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
29Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Lobes of the Cerebrum
30
• Five (5) lobes bilaterally:
• Frontal lobe
• Parietal lobe
• Temporal lobe
• Occipital lobe
• Insula aka ‘Island of
Reil’
(c)
Parietal lobe
Central sulcus
Occipital lobeFrontal lobe
Insula
Retracted temporal lobe
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
31Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Functions of the Cerebral Lobes
32
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Functional Regions of the Cerebral Cortex
33
Cerebral cortex:
Thin layer of gray matter that constitutes the outermost portion of
cerebrum, contains 75% of all neurons in the nervous system
Frontal eye field
Central sulcus
Parietal lobe
Occipital lobe
Cerebellum
Brainstem
Interpretation of auditory
patterns
Lateral sulcus
Auditory area
Sensory areas involved with
cutaneous and other senses
Sensory speech area
( Wernicke’s area)
Combining visual images,
visual recognition of objects
Visual area
Temporal lobe
Motor speech area
(Broca’s area)
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Front lobe
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Motor Areas (pre-central sulcus)
34
Frontal eye field
Central sulcus
Parietal lobe
Occipital lobe
Cerebellum
Brainstem
Interpretation of auditory patterns
Lateral sulcus
Auditory area
Sensory areas involved with
cutaneous and other senses
Sensory speech area
( Wernicke’s area)
Combining visual images,
visual recognition of
objects
Visual area
Temporal lobe
Motor speech area (Broca’s area)
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Front lobe
• Primary motor areas
• Frontal lobes
• Control voluntary muscles
• Broca’s area
• Anterior to primary motor
cortex
• Usually in left hemisphere
• Controls muscles needed
for speech
• Frontal eye field
• Above Broca’s area
• Controls voluntary movements
of eyes and eyelids
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Motor Areas
35
Parietal lobe
Sensory area
Central sulcus
Motor area
Frontal lobe
Swallowing
ForearmArm Pelvis
Thigh
Leg
Lips
Forearm ArmNeck Pelvis
Thigh
Leg
Genitals
(a) Motor area (b) Sensory area
Longitudinal
fissure
Salivation
Vocalization
Mastication
Facial
expression
Thumb,
fingers,
and hand
Trunk
Foot and
toes
Tongue and
pharynx
Teeth and
gums
Upper
face
Hand, fingers,
and thumb
Trunk
Foot and
toes
Longitudinal
fissure
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Sensory Areas (post-central sulcus)
36
• Cutaneous sensory area• Parietal lobe
• Interprets sensations on
skin
• Visual area• Occipital lobe
• Interprets vision
• Auditory area• Temporal lobe
• Interprets hearing
• Sensory area for taste
• Near base of the central sulcus
• Sensory area for smell• Arises from centers deep within
the cerebrum
Frontal eye field
Central sulcus
Parietal lobe
Occipital lobe
Cerebellum
Brainstem
Interpretation of auditory patterns
Lateral sulcus
Auditory area
Sensory areas involved with
cutaneous and other senses
Sensory speech area
( Wernicke’s area)
Combining visual images,
visual recognition of
objects
Visual area
Temporal lobe
Motor speech area
(Broca’s area)
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Front lobe
Wednesday, December 17,
2014
ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Sensory Areas
37
Parietal lobe
Sensory area
Central sulcus
Motor area
Frontal lobe
Swallowing
ForearmArm Pelvis
Thigh
Leg
Lips
Forearm ArmNeck Pelvis
Thigh
Leg
Genitals
(a) Motor area (b) Sensory area
Longitudinal
fissure
Salivation
Vocalization
Mastication
Facial
expression
Thumb,
fingers,
and hand
Trunk
Foot and
toes
Tongue and
pharynx
Teeth and
gums
Upper
face
Hand, fingers,
and thumb
Trunk
Foot and
toes
Longitudinal
fissure
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Association Areas
38
• Regions that are not primary motor or primary sensory areas.
• Widespread throughout the cerebral cortex.
• Analyze and interpret sensory experiences.
• Provide memory, reasoning, verbalization, judgment, emotions…
Frontal eye field
Central sulcus
Parietal lobe
Occipital lobe
Cerebellum
Brainstem
Interpretation of auditory patterns
Lateral sulcus
Auditory area
Sensory areas involved with
cutaneous and other senses
Sensory speech area
( Wernicke’s area)
Combining visual images,
visual recognition of
objects
Visual area
Temporal lobe
Motor speech area
(Broca’s area)
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Front lobe
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Association Areas
39
• Frontal lobe association areas
• Concentrating
• Planning
• Complex problem solving
• Parietal lobe association areas
• Understanding speech
• Choosing words to express
thought
• Temporal lobe association areas
• Interpret complex sensory
experiences
• Store memories of visual scenes,
music, and complex patterns
• Occipital lobe association areas
• Analyze and combine visual
images with other sensory
experiences
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Hemisphere Dominance
40
• The left hemisphere is dominant in most individuals
• Dominant hemisphere controls:
• Speech
• Writing
• Reading
• Verbal skills
• Analytical skills
• Computational skills
• Nondominant hemisphere controls:
• Nonverbal tasks
• Motor tasks
• Understanding and interpreting
musical and visual patterns
• Provides emotional and intuitive
thought processes
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Memory
41
• Short term memory
• Working memory
• Closed neuronal circuit
• Circuit is stimulated over and
over
• When impulse flow ceases,
memory does also unless it
enters long-term memory via
memory consolidation
• Long term memory
• Changes structure or
function of neurons
• Enhances synaptic
transmission
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
FUNCTIONS OF CEREBRUM.
42
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Functions of the Cerebrum
43
• Interpreting impulses• Initiating voluntary movements• Storing information as memory• Retrieving stored information • Reasoning• Seat of intelligence and personality
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
STRUCTURE OF BASAL NUCLEI
44Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Basal Nuclei /Basal Ganglia
45
Basal nuclei are masses of grey
matter deep within the white
matter of cerebral hemisphere with
connections to the cerebral cortex
and thalamus.
The basal nuclei form part of the
extrapyramidal tracts and are
involved in initiating muscle tone
in slow and coordinated activities.
• Caudate nucleus, putamen, and
globus pallidus.
• Produce dopamine.
Thalamus
Hypothalamus
Brainstem
Putamen
Cerebellum
Spinal cord
Longitudinal
fissure
Right cerebral
hemisphereCaudate
nucleus
Globus
pallidus
Basal
nuclei
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
46
Thalamus
Hypothalamus
Brainstem
Putamen
Cerebellum
Spinal cord
Longitudinal
fissure
Right cerebral
hemisphereCaudate
nucleus
Globus
pallidus
Basal
nuclei
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Basal ganglia lateral to thalamus is the
lentiform nucleus (lens shaped) divided
into 2 as:
a. Globus pallidus (globus=ball,
pallidus=pale) closer to thalamus.
b. Putamen (putamen=shell) closer
to cerebral cortex.
Caudate nucleus (caud=tail) ‘C’ shaped,
large head, tail arches over the
thalamus.
Caudate nucleus along with putamen
and globus pallidus is known as corpus
striatum.
Subthalamic nuclei interconnect the
globus pallidus in each cerebral
hemisphere.
47
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Functions:
To help regulate initiation and termination of movements in coordination with cerebral
cortex.
Putamen precedes or anticipates body movement.
Caudate nucleus responsible for eye movement.
Globus pallidus helps to regulate the muscle tone required for specific body movements.
It also controls subconscious contractions of skeletal muscles.
They initiate and coordinate cognitive processes such as attentions, memory, planning, and
may act with the limbic system to regulate emotional behaviours.
It estimates the passage of time.
It is associated with psychiatric disorders like:
o Obsessive compulsive disorder.
o Schizophrenia and
o Chronic anxiety all due to the dysfunction in circuits between basal ganglia and the
limbic system.
STRUCTURE OF DIENCEPHALON
48Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Diencephalon
49
• Between cerebral hemispheres and above the brainstem.
• Surrounds the third ventricle.
•Thalamus.
• Epithalamus.
• Hypothalamus.
• Optic tracts.
• Optic chiasm.
• Infundibulum.
• Posterior pituitary.
• Mammillary bodies.
• Pineal gland.Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
50Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Diencephalon
51
Thalamus:
•It makes up 80% of the diencephalon.
•The thalamus consists of two masses of nerve cells
(nuclei) and fibres, situated within the cerebral
hemispheres just below the corpus callosum, one on each
side of the third ventricle.
•It sends axons to regions of the cerebral cortex.
•Nuclei act as relay stations for incoming sensory
messages.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
52
Functions:
•Relays all sensory impulses to the cerebral cortex. Sensory input
from the skin, viscera and special sense organs is transmitted to the
thalamus (Receives all sensory impulses except smell).
•Afferent impulses converge on the thalamus. Nuclei organize and
amplify or tone down signals (Gateway for sensory impulses
heading to cerebral cortex).
•Channels impulses to appropriate part of cerebral cortex for
interpretation.
•Helps motor functions by transmitting information from the
cerebellum and basal ganglia to the primary motor area of the
cerebral cortex.
•Also helps in maintaining consciousness.Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Diencephalon
53
Hypothalamus:
•It is composed of a number of group of nerve cells.
•It is situated inferior and anterior to the thalamus, immediately
above the pituitary gland (pituitary gland projects inferiorly).
•The hypothalamus is linked to the posterior lobe of the pituitary
gland by nerve fibres and to the anterior lobe by a complex system
of blood vessels.
•Maintains homeostasis by regulating visceral activities.
• Links nervous and endocrine systems (hence some say the
neuroendocrine system.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
54
Functions:
• Control of the endocrine system (The secretion of hormones from both lobes
of the pituitary gland).
• The control of the autonomic nervous system (mainly visceral control center
of the body).
• The control of emotional responses (e.g. pleasure, fear, rage sexual
behaviour including mating and child rearing), control of behavior.
• Regulation of body temperature.
• Regulation of hunger and thirst sensations.
• Regulation of sleep-wake cycles: Biological clocks or circadian rhythms
(e.g. sleeping and waking cycles) by hormone melatonin from pineal gland.
• Formation of memory.Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Diencephalon
55
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Epithalamus:
• Forms part of the “roof” of the third ventricle, consists of a
tiny group of nuclei Includes the pineal gland (pineal
body), which secretes the hormone melatonin under
influence of the hypothalamus and the habenular nuclei.
Infundibulum:
• A hollow funnel shaped stalk that connects the
Hypothalamus and the posterior lobe of pituitary.
56
The Limbic System (the emotional brain)
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
1. Limbic lobe – rim of cerebral cortex on the medial surface of each hemisphere.
a. Allows us to shift between thoughts.
b. Interprets pain as unpleasant – cingulate gyrus (cingul=belt) lies above corpus callosum.
Parahippocampal gyrus lies in the temporal lobe below.
2. Dentate gyrus (dentate=tooth head) – lies between hippocampus (seahorse shape) and
parahippocampal gyrus.
3. Amygdala (amygda=almond shaped) stimulation of it produces fear and aggression. It composed of
groups of neurons located close to caudate nucleus.
4. Septal nuclei – lies in the septal area formed by regions under corpus callosum and the paraterminal
gyrus (cerebral gyrus).
5. Mammillary bodies of the hypothalamus – they are the 2 round masses near the cerebral peduncles.
6. Anterior and medial nucleus – it participate in limbic circuits.
7. Olfactory bulbs – flattened bodies of olfactory pathway that rests on the cribriform plate of the ethmoid
bone of the skull.
8. Fornix, striaterminalis, striamedullaris, medial forebrain bundle and mammillothalamic tract are
interconnected by bundles of myelinated axons.
57
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
58
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
59
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
60
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
61
Functions:
It plays an important role in a range of emotions including pain,
pleasure, docility, affection and anger (helps in experiencing intense
pain or extreme pleasure).
It is also involved in olfactory (smelling) and memory.
Stimulation of limbic system area produces tameness and affection.
Hippocampus functions in memory.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
THE STRUCTURE OF BRAIN STEM
62Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Brainstem
63
Three parts:
1. Medulla Oblongata
2. Pons
3. Midbrain
Spinal cord
Thalamus
HypothalamusDiencephalon
Pons
Midbrain
Corpus
callosum
Corpora quadrigemina
Cerebral
aqueduct
Reticular
formation
Medulla
oblongata
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Medulla Oblongata
64
Pyramidal tract
Pons
Optic nerve Optic chiasma
Thalamus
Spinal cord
Pituitary gland
Pineal gland
Optic tractMammillary body
(a) (b)
Olive
Corpora quadrigemina
Cerebral
peduncles
Superior
colliculus
Inferior
colliculus
Third
ventricle
Fourth
ventricle
Cerebellar
pedunclesMedulla
oblongata
• Enlarged continuation of
spinal cord
• Conducts ascending and
descending impulses between
brain and spinal cord
• Contains cardiac, vasomotor,
and respiratory control
centers.
• Contains various nonvital
reflex control centers
(coughing, sneezing,
swallowing, and vomiting)
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
65Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
66Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
67Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Pons
68
Pyramidal tract
Pons
Optic nerve Optic chiasma
Thalamus
Spinal cord
Pituitary gland
Pineal gland
Optic tractMammillary body
(a) (b)
Olive
Corpora quadrigemina
Cerebral
peduncles
Superior
colliculus
Inferior
colliculus
Third
ventricle
Fourth
ventricle
Cerebellar
pedunclesMedulla
oblongata
• Rounded bulge on underside
of brainstem.
• Between medulla oblongata
and midbrain.
• Helps regulate rate and
depth of breathing.
• Relays nerve impulses to and
from medulla oblongata and
cerebellum.
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Midbrain
• Between diencephalon and pons
• Contains bundles of fibers that join lower parts of brainstem and spinal cord with
higher part of brain
• Cerebral aqueduct
• Cerebral peduncles (bundles of nerve fibers)
• Corpora quadrigemina (centers for visual and auditory reflexes)
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
70Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
71Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
72Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Reticular Formation
73
•The reticular formation is a
collection of neurones in the core
of the brain stem (runs through
the central core of the medulla,
pons and midbrain), surrounded
by neurons which conduct
ascending and descending nerve
impulses between the brain and
the spinal cord. It has widespread
connections ideal for arousal of
the brain as a whole
•Filters incoming sensory
information.
• Arouses cerebral cortex into
state of wakefulness.
Spinal cord
Thalamus
HypothalamusDiencephalon
Pons
Midbrain
Corpus
callosum
Corpora
quadrigemina
Cerebral
aqueduct
Reticular formation
Medulla
oblongata
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
74
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Functions:
The reticular formation is involved in:
Coordination of skeletal muscle activity associated with voluntary
motor movement and the maintenance of balance.
Coordination of activity controlled by the autonomic nervous system,
e.g. cardiovascular, respiratory and gastrointestinal activity.
Selective awareness that functions through the reticular activating
system (RAS) which selectively blocks or passes sensory information
to the cerebral cortex (Maintains consciousness, alertness and also
functions in sleep and arousal from sleep).
Types of Sleep
75
• Slow wave
• Non-REM sleep
• Person is tired
• Decreasing activity of
reticular system
• Restful
• Dreamless
• Reduced blood pressure and
respiratory rate
• Ranges from light to heavy
• Alternates with REM sleep
• Rapid Eye Movement (REM)
• Paradoxical sleep
• Some areas of brain active
• Heart and respiratory rates irregular
• Dreaming occurs
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
STRUCTURE OF CEREBELLUM
76Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Cerebellum
77
• Situated inferior to occipital
lobes, posterior to pons and
medulla oblongata
• Has two hemispheres.
• Vermis connects hemispheres.
• Cerebellar cortex (gray matter).
• Arbor vitae tree of life (white
matter).
• Cerebellar peduncles (nerve fiber
tracts).
• Dentate nucleus (largest nucleus
in cerebellum).
Thalamus
Superior
peduncle
Middle peduncle
Inferior peduncle
Pons
Medulla oblongata
Cerebellum
Corpus callosum
Longitudinal
fissure
Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
78Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
79
Functions:
•Integrates sensory information concerning
position of body parts.
•Smoothens and coordinates contractions
of skeletal muscles.
•Regulates posture and balance.
•Cognition and language processing.Wednesday, December 17,
2014ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.
Wednesday, December 17,
2014
80
ST.JOSEPH’S COLLEGE OF PHARMACY, CHERTHALA.