Midterm Exam Prep - Neuroanatomy PDF

Midterm Exam: Principles in Neuroanatomy Anatomical and Functional Organization of the Nervous System The Nervous System Consists of Central and Peripheral Divisions Central nervous system (CNS): the brain and spinal cord. Peripheral nervous system (PNS): all parts of the nervous s...

Midterm Exam: Principles in Neuroanatomy Anatomical and Functional Organization of the Nervous System The Nervous System Consists of Central and Peripheral Divisions Central nervous system (CNS): the brain and spinal cord. Peripheral nervous system (PNS): all parts of the nervous system found outside the skull and spinal column. Nerves: a collection of axons bundled together outside the central nervous system. The Central and Peripheral Nervous Systems The Peripheral Nervous System (PNS) Peripheral nervous system (PNS): Somatic nervous system: connects brain and major muscles and sensory systems. Autonomic nervous system: Nerves that primarily control the viscera (internal organs) Enteric nervous system: local network of neurons that governs function of the gut The Somatic Nervous System The somatic nervous system has two major divisions: The cranial nerves: a set of 12 paired nerves that emerge directly from the brain (including the brainstem) rather than the spinal cord. The spinal nerves: Spinal nerves are 31 pairs of nerves that emerge from the spinal cord and connect the spinal cord to the body. The Somatic Nervous System: The Cranial Nerves The Somatic Nervous System: The Spinal Cord and Spinal Nerves The Autonomic Nervous System The autonomic nervous system has three major divisions: Sympathetic nervous system Parasympathetic nervous system Enteric nervous system The Autonomic Nervous System: The Sympathetic and Parasympathetic Systems Sympathetic nervous system: activation prepares the body for action (fight or flight response->increased blood pressure, heart rate, pupils dilate). Parasympathetic nervous system: activation is often in opposition to sympathetic activity (rest and digest). The Autonomic Nervous System: Sympathetic vs. Parasympathetic The Autonomic Nervous System: The Enteric Nervous System The enteric nervous system (ENS) is a complex and specialized subdivision of the autonomic nervous system that primarily governs the function of the gastrointestinal (GI) tract. The ENS is responsible for managing the processes of digestion, including the movement of food through the digestive tract (peristalsis), secretion of digestive enzymes, absorption of nutrients, and regulation of blood flow to the gut. The Autonomic Nervous System: The Enteric Nervous System Sometimes referred to as the "second brain," the ENS operates largely independently of the central nervous system (CNS), though it does communicate with it. Brain-Body Orientation: Six Views of the Brain Anterior View Posterior View Dorsal View Ventral View Lateral View Midsagittal View Three Customary Orientations for Viewing the Brain Three orientations for viewing the brain and body: Horizontal plane—divides brain into an upper (dorsal) and lower part (ventral) Sagittal plane—divides brain into right and left halves (medial towards midline, lateral away from the midline); midsagittal means directly in the center/middle Coronal plane—divides brain into front (anterior) and back (posterior) regions Three Customary Orientations for Viewing the Brain and Body Horizontal Plane Sagittal Plane Coronal Plane Two Colors of Brain Tissue: White Matter and Gray Matter Two main colors of brain tissue: White matter: Consists mostly of axons with white myelin sheaths. o Fiber/Tract—a bundle of axons Gray matter: Contains more cell bodies and dendrites, which lack myelin. o Nuclei—a collection of neurons White Matter – axonal fiber tracts; are white due to myelin Gray Matter – neuronal cell bodies and dendrites White Matter Gray Matter Gyri (gyrus sing.) – smooth/flat surface of the cerebral cortex Sulci (sulcus sing.) – groves/indentations of the cerebral cortex Gyri Sulci Specialized Support Systems Protect and Nourish the Brain Brain and spinal cord are surrounded by three protective membranes, the meninges: Dura mater— (Latin “tough mother”) tough outermost sheet Arachnoid—(Latin “spiderweb-like) substance between the dura mater and pia mater that cushions the brain Pia mater— (Latin “tender mother) delicate innermost layer The Meninges: Three Protective Membranes: Overview of the Brain: A Lateral View Overview of the Brain: Midsagittal (midline) View Overview of the Brain: Ventral View (from below) Cerebral Cortex - outermost layer of the brain, involved in higher level processing Longitudinal Fissure - separates the left and right cerebral hemispheres Frontal Lobe - higher level cognition; motor control Parietal Lobe - processes spatial information Central Sulcus - a fissure that divides the frontal lobe from the parietal lobe Temporal Lobe - audition (hearing); olfaction (smell), aspects of learning Sylvian (Lateral) Fissure - a deep fissure that separates temporal lobe from frontal and parietal lobes Occipital Lobe - visual processing Precentral Gyrus - primary motor cortex (movement control); anterior to central sulcus Postcentral Gyrus - primary somatosensory cortex (touch), posterior to central sulcus Prefrontal Cortex - cognitive control; regulates attention; problem solving Orbitofrontal Cortex - decision making; influences emotional responses Auditory Cortex - processing of auditory (sound) stimuli Broca’s Area - speech production Broca’s Area Wernicke’s Area - language comprehension Wernicke’s Area Cingulate Gyrus - helps regulate emotion and pain Corpus Callosum - nerve fiber tracts that connects the two cerebral hemispheres. Fornix - aids in the recall of episodic memory Thalamus - the sensory “relay” station; sends sensory information to cortex Hypothalamus - homeostasis, hunger/thirst, body temperature, controls pituitary Pineal Gland - secretory gland that releases melatonin Superior Colliculus - paired gray matter structures that receive visual information Inferior Colliculus - paired gray matter structures that receive auditory information Midbrain - integrates sensory information; helps to respond to sound Pons - breathing and heart rate; sleep and dreaming Medulla - breathing, heart rate, blood pressure Cerebellum - regulation of movement, coordination, balance, and posture Olfactory Bulbs - provides receptors for smell Optic Chiasm - point where two optic nerves meet; directs visual stimuli Mammillary Bodies – aids in long-term memory consolidation Basal Ganglia - includes structures important for motor control and movement Caudate Nucleus - motor planning, integrates spatial information with motor behavior Putamen - involved in the general execution of all movements Globus Pallidus - controls conscious and proprioceptive awareness/movements Substantia Nigra - “black substance” modulates movements, produces dopamine Subthalamic Nucleus (photo is a horizontal cut and dorsal view of midbrain) - involved in motor impulse control and stopping movements Limbic System - includes structures important for emotion, memory, and cognition Amygdala - regulates emotion (fear and aggressive behavior) Hippocampus - facilitates learning and memory Stria Terminals - controls autonomic, neuroendocrine, and behavioral responses Septal Nuclei - plays a role in pleasure, reward, and reinforcement Septal Nuclei The Ventricular System: The Cerebral Ventricles Cerebral Ventricular System Third Ventricle - produces and secretes CSF Lateral Ventricle - circulates nutrients to brain - removes waste Cerebral Aqueduct - canal that connects third and fourth ventricle Interventricular Foramen - contains choroid plexus (cells surrounding blood vessels that produce CSF) Fourth Ventricle - main cushion and shock absorber for the brain