brain gross anatomy
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Brain-2
BrainAnterior
Posterior Inferior view
Brain-3
Brain: Gross Anatomy• Brain
– Part of CNS contained in cranial cavity
• Brainstem: connects spinal cord to brain; integration of reflexes necessary for survival
• Cerebellum: involved in control of locomotion, balance, posture
• Diencephalon: thalamus, subthalamus, epithalamus, hypothalamus
• Cerebrum: conscious thought, control
Brain-4
Sagittal Section of Brain
Cerebrum
Cerebellum
Thalamus
Hypothalamus
Midbrain
Pons
Medulla Oblongata
Brainstem
Diencephalon
Brain-5
Brainstem
Pyramid
(a) Anterior view
(b) Posterolateral view
Midbrain
MidbrainPons
Brainstem
Olive
Superior colliculusInferior colliculus
Olive
Pons
Brainstem
Superior cerebellarpeduncleMiddle cerebellarpeduncleInferior cerebellarpeduncle
Medulla oblongata
Medullaoblongata
Pyramidaldecussation
Brain-7
BrainstemMedulla Oblongata
• transmits ascending and descending impulses between the brain and spinal cord
• pyramids – nerve tracts – conscious control of skeletal muscle
• center for vital reflexes – heart rate, BP, respiration, swallowing, coughing, sneezing
• olives - nuclei involved in balance, coordination, modulation of sound
• nuclei of cranial nerves V, VII, IX, X, XI, XII
Brain-8
BrainstemPons
• ascending and descending nerve tracts
• nuclei
• sleep centre, respiratory centre
Anterior• Pontine nuclei – communication between
cerebrum and cerebellum
Posterior• nuclei of cranial nerves V, VI, VII, VIII
BrainstemMidbrain• most superior portion of the brainstem
• nuclei of cranial nerves III, IV, V
• Tectum: 4 nuclei - form mounds on dorsal surface of midbrain
- each separate part is a colliculus
- two superior colliculi involved in visual reflexes
- two inferior colliculi involved in hearing
Reticular Formation
• Group of nuclei scattered throughout brainstem
• Cloud throughout the brainstem
• Controls cyclic activities such as sleep-wake cycle
Brainstem
Brain-10
Brain-11
Purkinje cell
Golgicell
Granulecell
Mossy fiberAxon of Purkinje cell
(b) Inferior view
Cerebellum
Lateral hemisphere
FoliaVermis
Anteriorlobe
Posteriorlobe
Vermis
Anterior lobe
FoliaPons
Flocculonodularlobe
Lateralhemisphere
Medullaoblongata
Posteriorlobe
Arborvitae
(a) Medial view
Vermis
Flocculonodular lobe
Brain-13
CerebellumCommunicates with other regions of the CNS:
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superior cerebellar peduncle – midbrain
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middle cerebellar peduncle – pons
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inferior cerebellar peduncle – medulla oblongata
3 Regions:
1. Flocculonodular lobe – balance2. Vermis – gross motor coordination (Anterior), fine
motor coordination (Posterior)3. Lateral hemisphere – fine motor coordination
Brain-14
Diencephalon• between brainstem and cerebrum• 4 main components:
• Thalamus• Subthalamus• Epithalamus• Hypothalamus
Diencephalon, medial view
ThalamusInterthalamicadhesion
Hypothalamus
Pituitary gland
HabenulaPineal gland Epithalamus
Subthalamus
Brain-16
DiencephalonThalamus• largest part of the diencephalon
• lateral portions connected by interthalamic adhesion - surrounded by third ventricle
• receives major portion of sensory input – projections to cerebral cortex
• Auditory impulses – medial geniculate nucleus
• Visual impulses – lateral geniculate nucleus
Interthalamicadhesion
Lateral geniculatenucleus
Brain-18
DiencephalonSubthalamus
• inferior to the thalamus
• ascending and descending nerve tracts
• subthalamic nuclei – controlling motor function
Thalamus
Hypothalamus Subthalamus
Brain-19
DiencephalonEpithalamus
• posterior and superior to the thalamus
• Habenula – emotional and visceral responses to odor
• Pineal gland – may influence the onset of puberty
Thalamus
Hypothalamus
HabenulaPineal gland EpithalamusSubthalamus
Brain-21
DiencephalonHypothalamus• most inferior portion of the diencephalon
• contains a stalk – infundibulum connecting the hypothalamus to the pituitary gland
• link between the nervous and endocrine system
• many clusters of nuclei that control bodily functions
• mood and emotion
Paraventricularnucleus
Infundibulum
Supraopticnucleus
Preoptic area
Pituitary gland
Brain-23
Cerebrum• outer layer – cerebral cortex (gray matter)
• deep clusters of nuclei (gray matter)
• in between – cerebral medulla (white matter)
Gray matter
White matter
Basal nuclei
Brain-24
Cerebrum
Anterior
Frontal lobe-Motor function-Aggression, mood
Parietal lobe-touch, taste, pressure-blood pH-not smell, vision, hearing
Occipital lobe-reception and integration of visual input
Temporal lobe-olfactory, auditory input-memory
Central sulcus
Lateral fissure
Brain-26
CerebrumCerebral Medulla
• nerve tracts connect the cortex to other areas of cortex or other parts of the CNS
• Association fibers – connect areas of cerebral cortex within the same hemisphere
• Commissural fibers – connect the cerebral hemispheres (Corpus Callosum)
• Projection fibers – between the cerebrum and other parts of the brain and spinal cord (Internal capsule)
Brain-27
CerebrumCerebral Medulla
Longitudinalassociationfibers
Commissural fibers(corpus callosum)
NucleiCortex
Shortassociationfibers
Projection fibersInternalcapsule Cerebral
medulla
Association fibersCommissural fibersProjection fibers
(a) Anterior view
Projectionfibers inthe internalcapsule
AnteriorCerebrum
Brainstem
(b) Lateral view Cerebellum
Posterior
Brain-28
Meninges
(a) Anterosuperior view
Skull
Subdural space
Arachnoid mater
Subarachnoid space
Pia mater
Cerebrum
Periosteal duraMeningeal dura
Dura mater
Dural venous sinus(superior sagittal sinus)
Brain-29
Ventricles
Lateral ventricle
Cerebral aqueduct
Fourth ventricle
Third ventricle
Lateral view
Posterior horn oflateral ventricle
Central canalof spinal cord
Anterior horn oflateral ventricleInterventricularforamen
Inferior horn oflateral ventricle
Brain-30
Cerebrospinal Fluid
Ependymalcells
Connectivetissue
Capillarycontainingblood CSF enters
the ventricle
Section of choroidplexus
Choroid plexus oflateral ventricle
1
2
3
4
5
1
• serum-like fluid lacking proteins, but containing nutrients• bathes and protects the brain and spinal cord• most synthesized in the choroid plexus – lateral ventricles
Superiorsagittal sinus
Arachnoid granulation
Subarachnoid space
Median aperture
Lateral aperture
Subarachnoid spaceCentral canal ofspinal cord
i Clicker QuestionThe pyramids are __________ nerve tracts
that are involved in the conscious control of __________ .
A. ascending, smooth muscle B. ascending, skeletal muscle C. descending, smooth muscle D. descending, cardiac muscle E. descending, skeletal muscle
The medulla oblongata does not include the
A. nuclei of some cranial nervesB. OlivesC. PyramidsD. centers for some vital reflexesE. thalamus
i Clicker Question
iClicker Question
The pineal gland is found in the
A. subthalamus. B. thalamus. C. epithalamus. D. hypothalamus. E. pons.
i Clicker Question
The infundibulum connects
A. the hypothalamus and pituitary gland. B. the thalamus and hypothalamus. C. the thalamus and epithalamus. D. the thalamus and subthalamus. E. the medulla and the pons.
i Clicker Question
The primary motor cortex is located in the
A. frontal lobe. B. occipital lobe. C. postcentral gyrus. D. precentral gyrus. E. temporal lobe.
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