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The Brain. Late Developmental Regions. Structure Derived from Regions. Early Developmental Regions. Thalamus . The 6 Divisions of the Brain. . (Cerebrum). Epithalamus. . . . . . General Anatomy of Cerebrum: Two Hemispheres - Left and Right.
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Late Developmental Regions Structure Derived from Regions Early Developmental Regions Thalamus
The 6 Divisions of the Brain (Cerebrum) Epithalamus
General Anatomy of Cerebrum: Two Hemispheres - Left and Right. • Two significant gyri: Precentral gyrus (motor). • Postcentral gyrus (sensory).
Five Lobes of the Cerebrum • Frontal • Parietal • Temporal • Occipital • Insula
Cerebral Nuclei Or Basal ganglia
Functions of the Cerebrum • Awareness of ourselves and sensations. • Initiate and control voluntary movements. • Communicate • Memory. Cerebrum has 5 Lobes Frontal Lobe - memory, behavior, personality, movement. Parietal Lobe - somatic sensory perception. Temporal Lobe - auditory and olfactory perception. Occipital Lobe - visual perception. Insula Lobe - visceral perception.
Broca’s area Wernike’s area
The Limbic System = “Emotional Brain” • Anatomical Location: • Medial aspect of cerebral hemispheres. • Also within the diencephalon. • Composed of: • Septal nuclei, cingulate gyrus, hippocampus and amygdala. • The fornix links the limbic system together.
The Reticular System - widespread connections, ideal for arousal of the brain as a whole. Reticular activating system (RAS) - Maintains consciousness and alertness. Functions in sleep and arousal from sleep.
Diencephalon = 1) Epithalamus, 2) Thalamus and 3) Hypothalamus 1) Epithalamus - Forms “roof” of third ventricle. - Includes the pineal gland (body). Releases melatonin.
2) Thalamus • Largest portion of the diencephalon. * Contains ~ a dozen major nuclei which act as the “gateway” to cerebral cortex. * Afferent impulses converge on thalamus. * Nuclei organize and amplify or tone down signals - habituation
3) Hypothalamus Main visceral control center of the body Regulates body temperature Regulates circadian rhythms Processes olfaction and feeding reflexes
Functions of the Hypothalamus: • 1. Controls autonomic nervous system (ANS) • 2. Control of the endocrine system • 3. Regulation of body temperature (Tb) • 4. Regulation of hunger and thirst sensations • 5. Regulation of sleep-wake cycles 6. Sex drive • Overall: Controls much of behavior via emotional • responses (Limbic) and ANS - Formation of memory
The Brain Stem Midbrain, Pons, Medulla Oblongata
Midbrain Tectum Corpora quadrigemina = ‘four bodies’ (2 pairs) Superior colliculi => nuclei that act in visual reflexes (vision). Inferior colliculi => nuclei that act in auditory reflexes (sound).
The Cerebellum – superior view Located dorsal to the pons and medulla Consists of two cerebellar hemispheres Folia
Functions of Cerebellum Located dorsal to the pons and medulla 1)Controls postural reflexes: - coordinates rapid, automatic adjustments of muscles in body to maintain equilibrium. 2)Produces skilled movements:- - implements routines for fine tuned movements. Refines learned routines (e.g. driving, playing an instrument) until the action becomes routine.
* Thick tracts connecting the cerebellum to the brain stem * Superior, Middle and Inferior Cerebellar Peduncles * Fibers to and from the cerebellum are ipsilateral - run to and from the same side of the body
Pons * Contains the pontine respiratory centers. * Contains the nuclei of cranial nerves V, VI, and VII