Gross Structure of the Brain

Nervous System  CNS (central nervous system) Brain Spinal Cord  PNS (peripheral nervous system) Peripheral Nerve Ganglion  CNS (central nervous system) Brain Spinal Cord  PNS (peripheral nervous system) Peripheral Nerve Ganglion

Central Nervous System - Brain

Gross Divisions of the Brain  Cerebrum (cerebral hemisphere)  Diencephalon  Cerebellum  Brainstem  Cerebrum (cerebral hemisphere)  Diencephalon  Cerebellum  Brainstem

telencephalon Cerebral cortex Cerebral white matter Basal ganglia Cerebral cortex Cerebral white matter Basal ganglia metencephalon Cerebellum Pons Cerebellum Pons Primary vesicle Secondary vesicle Derivatives Prosencephalon diencephalon Thalamus Hypothalamus Subthalamus Epithalamus Thalamus Hypothalamus Subthalamus Epithalamus Mesencephalon mesencephalon Midbrain Rhombencephalon myelencephalon Medulla oblongata Embryonic (developmental) divisions of the Brain

Inner Structures of the Brain 1.Basal ganglia 2.Thalamus 3.Hypothalamus 4.Midbrain 5.Pons 6.Medulla oblongata 1.Basal ganglia 2.Thalamus 3.Hypothalamus 4.Midbrain 5.Pons 6.Medulla oblongata

Cerebrum – Cerebral Hemisphere 1.Cerebral Cortex - lobes, gyrus & sulcus 2. Cerebral White Matter (medullary center) 3. Basal Ganglia 1.Cerebral Cortex - lobes, gyrus & sulcus 2. Cerebral White Matter (medullary center) 3. Basal Ganglia Telencephalic structure –lateral ventricles

Lobes of the Cerebral Cortex (lateral surface) 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe

Lobes of the Cerebral Cortex (medial surface) 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe

Lobes of the Cerebral Cortex (basal surface) Lobes of the Cerebral Cortex (basal surface) 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe 1.Frontal lobe 2.Parietal lobe 3.Temporal Lobe 4.Occipital lobe 5.Limbic lobe

Lateral Surface Precentral Gyrus --- primary motor area Superior Frontal Gyrus Middle Frontal Gyrus Inferior Frontal Gyrus Pars Opercularis Pars Triangularis Pars Orbitalis Medial Surface Medial Frontal Gyrus Paracentral Lobule Basal Surface Rectus Gyrus Orbital Gyrus Inferior Frontal Gyrus Lateral Surface Precentral Gyrus --- primary motor area Superior Frontal Gyrus Middle Frontal Gyrus Inferior Frontal Gyrus Pars Opercularis Pars Triangularis Pars Orbitalis Medial Surface Medial Frontal Gyrus Paracentral Lobule Basal Surface Rectus Gyrus Orbital Gyrus Inferior Frontal Gyrus Gyri of the Frontal Lobe ] Broca’s area (dominant hemisphere)

Gyri of the Cerebral Cortex (Lateral Surface)

Broca’s area Pars Opercularis Pars Triangularis Pars Orbitalis

Gyri of the Cerebral Cortex (Medial Surface)

Gyri of the Cerebral Cortex (basal surface) Gyri of the Cerebral Cortex (basal surface)

Gyri of the Parietal Lobe Lateral Surface Postcentral Gyrus ---- primary somesthetic area Superior Parietal Lobule Inferior Parietal Lobule ---- Wernicke’s area Supramarginal Gyrus Angular Gyrus Medial Surface Paracentral Lobule Precuneus Lateral Surface Postcentral Gyrus ---- primary somesthetic area Superior Parietal Lobule Inferior Parietal Lobule ---- Wernicke’s area Supramarginal Gyrus Angular Gyrus Medial Surface Paracentral Lobule Precuneus

Gyri of the Cerebral Cortex (Lateral Surface)

Gyri of the Cerebral Cortex (Medial Surface)

Gyri of the Occipital Lobe Lateral Surface Lateral Occipital Gyrus Superior Occipital Gyrus Inferior Occipital Gyrus Medial Surface Cuneus Lingual Gyrus Basal Surface Lingual Gyrus Occipitotemporal Gyrus Lateral Surface Lateral Occipital Gyrus Superior Occipital Gyrus Inferior Occipital Gyrus Medial Surface Cuneus Lingual Gyrus Basal Surface Lingual Gyrus Occipitotemporal Gyrus

Gyri of the Cerebral Cortex (Lateral Surface)

Gyri of the Cerebral Cortex (Medial Surface)

Gyri of the Cerebral Cortex (basal surface) Gyri of the Cerebral Cortex (basal surface)

Gyri of the Temporal Lobe Lateral Surface Superior Temporal Gyrus Middle Temporal Gyrus Inferior Temporal Gyrus Basal Surface Lingual Gyrus Occipitotemporal Gyrus Medial Occipitotemporal Gyrus Lateral Occipitotemporal Gyrus Lateral Surface Superior Temporal Gyrus Middle Temporal Gyrus Inferior Temporal Gyrus Basal Surface Lingual Gyrus Occipitotemporal Gyrus Medial Occipitotemporal Gyrus Lateral Occipitotemporal Gyrus

Gyri of the Cerebral Cortex (Lateral Surface)

Gyri of the Cerebral Cortex (basal surface) Gyri of the Cerebral Cortex (basal surface)

Gyri of the Limbic Lobe Outer Ring Cingulate Gyrus Isthmus of Cingulate Gyrus Parahippocampal Gyrus Uncus, Uncinate Gyrus Inner Ring Hippocampal Formation Hippocampus, Ammon's Horn Dentate Gyrus Fasciolar Gyrus Indusium Griseum (Supracallosal Gyrus) Paraterminal Gyrus (Subcallosal Gyrus) Subcallosal Area (Parolfactory Area) Outer Ring Cingulate Gyrus Isthmus of Cingulate Gyrus Parahippocampal Gyrus Uncus, Uncinate Gyrus Inner Ring Hippocampal Formation Hippocampus, Ammon's Horn Dentate Gyrus Fasciolar Gyrus Indusium Griseum (Supracallosal Gyrus) Paraterminal Gyrus (Subcallosal Gyrus) Subcallosal Area (Parolfactory Area)

Gyri of the Cerebral Cortex (Medial Surface)

Gyri of the Cerebral Cortex (basal surface) Gyri of the Cerebral Cortex (basal surface)

Cerebral White Matter Projection fiber Corona radiata Commissural fiber Corpus callosum rostrum, genu, trunk, splenium Anterior commissure Commissure of fornix Association fiber Short association fiber Long association fiber Projection fiber Corona radiata Commissural fiber Corpus callosum rostrum, genu, trunk, splenium Anterior commissure Commissure of fornix Association fiber Short association fiber Long association fiber

Fibers of Cerebral White Matter (coronal section) 1. Corpus callosum 2. Internal capsule 3. Superior occipitofrontal fasciculus 4. Superior longitudinal fasciculus 5. Inferior occipitofrontal fasciculus 6. Cingulum 7. Uncinate fasciculus 8. Inferior longitudinal fasciculus 1. Corpus callosum 2. Internal capsule 3. Superior occipitofrontal fasciculus 4. Superior longitudinal fasciculus 5. Inferior occipitofrontal fasciculus 6. Cingulum 7. Uncinate fasciculus 8. Inferior longitudinal fasciculus

Basal Ganglia (traditional concept) Corpus striatum lenticular nucleus putamen globus pallidus caudate nucleus Amygdaloid body Corpus striatum lenticular nucleus putamen globus pallidus caudate nucleus Amygdaloid body

Diencephalon Thalamus Hypothalamus Epithalamus Subthalamus Thalamus Hypothalamus Epithalamus Subthalamus 3 rd ventricle and tela choroidea 3 rd ventricle and tela choroidea

Cerebellum Anterior Lobe Posterior Lobe Flocculonodular Lobe flocculus, nodulus Vermis Paravermal Region Cerebellar Hemisphere Anterior Lobe Posterior Lobe Flocculonodular Lobe flocculus, nodulus Vermis Paravermal Region Cerebellar Hemisphere

Brain Stem Midbrain Pons Medulla Oblongata 4 th Ventricle Rhomboid Fossa Midbrain Pons Medulla Oblongata 4 th Ventricle Rhomboid Fossa

The Nervous System A network of billions of nerve cells linked together i n a highly organized fashion to form the rapid control center of the body. Functions include: –Integrating center for homeostasis, movement, and almost all other body functions. –The mysterious source of those traits that we think of as s etting humans apart from animals

Basic Functions of the Nervous System 1.Sensation Monitors changes/events occurring in and outside the body. Such cha nges are known as stimuli and the cells that monitor them are receptors. 2.Integration The parallel processing and interpretation of sensory information to determine the appropriate response 3.Reaction Motor output. –The activation of muscles or glands (typically via the release of neurotransmitters (NTs))

Organization of the Nervous System 2 Initial divisions: 1.Central Nervous System The brain + the spinal cord –The center of integration and control 2.Peripheral Nervous System The nervous system outside of the brain and spinal cord Consists of: –31 Spinal nerves »Carry info to and from the spinal cord –12 Cranial nerves »Carry info to and from the brain

Peripheral Nervous System Responsible for communication btwn the CNS and the rest of the body. Can be divided into: –Sensory Division Afferent division –Conducts impulses from receptors to the CNS –Informs the CNS of the state of the body interior and exterior –Sensory nerve fibers can be somatic (from skin, skeletal muscles or joints) or visceral (from organs within the ventral body cavity) –Motor Division Efferent division –Conducts impulses from CNS to effectors (muscles/glands) –Motor nerve fibers

Motor Efferent Division Can be divided further: –Somatic nervous system VOLUNTARY (generally) Somatic nerve fibers that conduct impulses from the CNS to skeletal muscles –Autonomic nervous system INVOLUNTARY (generally) Conducts impulses from the CNS to smooth muscle, cardiac muscle, and glands.

Autonomic Nervous System Can be divided into: –Sympathetic Nervous System “Fight or Flight” Exercise, excitement, emergency and embarrassment –Parasympathetic Nervous System “Rest and Digest” –Digestion, defecation, and diuresis These 2 systems are antagonistic. Typically, we balance these 2 to keep ourselves in a state of d ynamic balance.

Antagonistic Control Most internal organs are innervated by both branches of the ANS which exhibit antagonistic control A great example is heart rate. An increase in sympathetic stimulation causes HR to increase whereas an increase in parasympathetic stimulation causes HR to decrease

ANS Structure Both ANS divisions share the same general structure. –Autonomic pathways always consist of 2 neurons in series. –They synapse in an autonomic ganglion The 1 st neuron in the auton omic pathway is the preganglionic n euron, Cell body in CNS, myelinated, and projects to the autonomic ganglion. –While the 2 nd neuron is the postganglionic neuron. Cell body in autonomic ganglion, unmyelinated, and projects to the effector.

Sympathetic vs. Parasympathetic Receptor/NT Differences: Symp.Parasymp. NT at Target SynapseNorepinephrine (adrenergic neurons) Acetylcholine (cholinergic neurons) Type of NT Receptors at Target Synapse Alpha and Beta (  and  ) Muscarinic NT at GanglionAcetylcholine Receptor at GanglionNicotinic

Target OrganParasympathetic Effects Sympathetic Effects Eye (Iris) Stimulates constrictor muscles. Pupil constriction. Stimulates dilator muscles. Pupil dilates. Eye (Ciliary muscle) Stimulates. Lens accommodates – allows for close vision. No innervation. Salivary Glands Watery secretion.Mucous secretion. Sweat Glands No innervation.Stimulates sweating in large am ounts. (Cholinergic) Gallbladder Stimulates smooth muscle to co ntract and expel bile. Inhibits gallbladder smooth mus cle. Arrector Pili No innervationStimulates contraction. Piloerect ion (Goosebumps)

Target OrganParasympathetic Effects Sympathetic Effects Cardiac Muscle Decreases HR.Increases HR and force of contra ction. Coronary Blood Vessels Constricts.Dilates Urinary Bladder; Urethr a Contracts bladder smooth muscl e; relaxes urethral sphincter. Relaxes bladder smooth muscle; contracts urethral sphincter. Lungs Contracts bronchiole (small air p assage) smooth muscle. Dilates bronchioles. Digestive Organs Increases peristalsis and enzyme /mucus secretion. Decreases glandular and muscul ar activity. Liver No innervationNo innervation (indirect effect).

Target OrganParasympathetic Effects Sympathetic Effects Mental Activity No innervation.Increases alertness. Blood Vessels Little effect.Constricts most blood vessels an d increases BP. Exception – dila tes blood vessels serving skeleta l muscle fibers (cholinergic). Uterus Depends on stage of the cycle. Endocrine Pancreas Stimulates insulin secretion.Inhibits insulin secretion.

How Does the Brain Control the ANS? The hypothalamus is the Boss: –Its anterior and medial regions direct parasympathetic function while its posterior and lateral regions direct sympathetic functio n –These centers exert control directly and via nuclei in the reticul ar formation (e.g., the cardiovascular centers in the MO, respira tory centers in MO and pons, etc.) –The connection of the limbic system to the hypothalamus media tes our “flight or flight” response to emotional situations. –The relationship btwn the hypothalamus and the amygdala and periaquaductal gray matter allow us to respond to fear.