Brain Structure
02.04.2016
Nervous System
Nervous System
Central Nervous
System
Brain
Spinal Cord
Peripheral
Nervous System
Cranial nerves,
spinal nerves,
peripheral ganglia
Brain
Brain
Brain Stem
Forebrain
Cerebral
Cortex
Basal
Ganglia
Limbic
System
Hindbrain
Midbrain
Diencephalon
Meninges of Central Nervous System
Meninges – protect and cover brain and spinal
cord
1. Dura mater
2. Arachnoid membrane
Subarachnoid space
3. Pia matter
https://www.youtube.com/watch?v=opfC4JIUPd0
Meninges of
Peripheral Nervous System
1. Dura mater
2. Pia mater
Brain Ventricles
• Two lateral ventricles
(1st and 2nd ventricles)
• 3rd ventricle
• 4th ventricle
• Cerebral aqueduct
connects 3rd and 4th ventricle
https://www.youtube.com/watch?v=Zm-TsqsgCHc
Cerebro-Spinal Fluid
Protection
1. reduce pressure (absorbs shock)
2. nutrition
3. waste removal
• Extracted from blood
• Manufactured by choroid plexus (in ventricles)
• Manufactured and reabsorbed continuously
• Reabsorbed into blood stream
https://www.youtube.com/watch?v=asQo6cmOjd0
Central Nervous System
• Brain
• Spinal cord
Brain – Gross Structure
Cerebral cortex:
Gyrus
“Bump” on the brain’s surface
Sulcus
Fold / groove between gyri
Fissure
A long, deep sulcus
Lobes of the Brain
Functional Brain Areas
Cerebral Cortex
• Divided into two hemispheres
– Connected by corpus callosum
• Left hemisphere
– Verbal, verbally mediated processes, analytical,
sequential information processing
• Right hemisphere
– Non-verbal, holistic, simultaneous information
processing
Corpus Callosum
• Largest white matter
tract
• Connect corresponding
parts of cortex in R and
L hemispheres
– Anterior
– Posterior
– Body
Corpus Colostomy
• To prevent spread of epileptic activity
• Split brain (Roger Sperry 1913-1994):
– Can not name image in left visual field
– Can not name object touched by left hand
– Personality, intelligence, emotions intact
https://www.youtube.com/watch?v=zx53Zj7EKQE
Forebrain
Basal Ganglia
• Multiple
subcortical
nuclei
• Main functions:
motor control,
eye movements,
motivation
Basal Ganglia
Parkinson’s disease
Loss of Dopamine producing cells in substantia nigra
Neurodegenerative disease
• Motor symptoms:
–
–
–
–
–
•
Tremor
Bradykinesia (slow movement)
Rigidity
Postural instability
Dysarthria, difficulty swallowing
Cognitive symtoms:
– Cognitive slowing, micrographia
– Distractability, disorganization, forgetfulness, difficulty planning
– Depression, apathy, anxiety
https://www.youtube.com/watch?v=3wg9ExKwZy4
Basal Ganglia
Huntington’s disease
Striatum
Neurodegenerative genetic disorder
Motor symptoms:
– Uncontrollable jerky movements
– Lack of coordination
– Unsteady gait
Cognitive symptoms:
– Memory, executive functions impairment
– Anxiety, depression
https://www.youtube.com/watch?v=4HgFUvVyHYQ
Limbic system
• Group of cortical
and subcortical
structures
• Main functions:
memory,
emotions,
arousal
https://www.youtube.com/watch?v=GDlDirzOSI8
https://www.youtube.com/watch?v=PNx9m54fjao
Limbic System
(functions of some structures)
Hippocampus
• Learning new memories (transfer from short-term memory to long-term
memory)
• Spatial memory
Amygdala
• Emotions (fear, anxiety)
• Prepare body for emergency reactions
• Attention
• Autobiographical memory (in particular, emotional memories)
• Social processing (in particular, recognition of emotions in others)
Thalamus
• Subcortical sensory relay
Hypothalamus
• Hormones production
Diencephalon
Thalamus – relays sensory
and motor signals to cortex,
regulates consciousness,
sleep, alertness
Hypothalamus – part of
endocrine system, links
nervous system to
endocrine system via
pituitary gland
• Four F’s
Brain Stem
Hindbrain
1. Metencephalon
– Pons Varolii – cranial nerves for
equilibrium, hearing, taste,
facial sensation& expressions
– Cerebellum – movement
coordination
2. Myelencephalon (medulla
oblongata)
- cranial nerves (VI-XII)
- IV ventricle
3. Reticular formation - activation
Midbrain, Mesencephalon
Tectum:
–
–
Superior colliculi - vision
Inferior colliculi - hearing
Tegmentum
- Movements
Reticular formation - arousal
Spinal Cord
Bell-Magendie Law
• Roots = bundles of axons
• Dorsal roots
 Axons entering spinal cord
 Carry sensory information
• Ventral roots
 Axons exiting spinal cord
 Carry motor information
Dorsal = Toward the back
Ventral = Toward the stomach
Signal Transmission
from and to the Spine
The Cranial Nerves
• 12 pairs of nerves (Left and Right)
 Connect brain to receptors and muscles of head and internal organs
 Originate in nuclei (groups of neurons) in brain
• Functions
 Sensation and movement in head
 Parasympathetic nervous system
The Cranial Nerves
Number and Name
Major Functions
I. Olfactory
Smell
II. Optic
Vision
III. Oculomotor
Control of eye movements, pupil constriction
IV. Trochlear
Control of eye movements
V. Trigeminal
Skin sensations from most of the face; Control of jaw muscles for chewing and
swallowing
VI. Abducens
Control of eye movements
VII. Facial
Taste from the anterior 2/3 of the tongue; Control of facial expressions, crying,
salivation, and dilation of the head’s blood vessels
VIII.Auditory/Vestibuloc Hearing, equilibrium
ochlear
IX. Glossopharyngeal
Taste and other sensations from throat and posterior 1/3 of the tongue; Control of
swallowing, salivation, throat movements during speech
X. Vagus
Sensations from neck and thorax; Control of throat, esophagus, and larynx;
Parasympathetic nerves to stomach, intestines, and other organs
XI. Spinal Accessory
Control of neck and shoulder movements
XII. Hypoglossal
Control of muscles of the tongue
The Cranial Nerves