Human Neuropsychology Lecture: Functional Anatomy of the Nervous System PDF

Human Neuropsychology Lecture 6 BIO N173 / PSY 163/ PSYCH 162 Functional Anatomy of the Nervous System 0 1 2 3  The Nervous System Functions Detect stimuli in the envir...

Human Neuropsychology Lecture 6 BIO N173 / PSY 163/ PSYCH 162 Functional Anatomy of the Nervous System 0 1 2 3  The Nervous System Functions Detect stimuli in the environment Recognize the significance of external stimuli Make decisions based on the significance Execute an appropriate response “Every function of the human body is under control of the nervous system” Gray’s Anatomy 40th ed. 4  Major Divisions The Peripheral Nervous System (PNS) Detect environmental stimuli Transmit information to the CNS Carry out orders given by the CNS The Central Nervous System (CNS) Receive and analyze information Make executive decisions Transmit decisions back to the PNS 5  Peripheral Nervous System Somatic Nervous System Afferent: carry information from sensory neurons to the CNS Efferent: carry information from the CNS to motor neurons Nerves are always in pairs, one efferent (motor) and one afferent (sensory) 31 pairs of spinal nerves 12 pairs of cranial nerves 6 PNS: Cranial Nerves (12 pairs) 7 PNS: Spinal Nerves (31 pairs) 8 Autonomic Nervous System The cervical nerves primarily serve somatic motor control and sensory function in the neck, shoulders, arms and diaphragm. Sexual Function: PANS initially promotes erection (vasodilation). SANS then controls ejaculation and vaginal contraction during orgasm (vasoconstriction). This ensures correct timing of things. Bladder Function: PANS contracts bladder and relaxes sphincter (urination). SANS relaxes bladder and contracts sphincter (urine storage). This prevents urination in stressful situations. 9 Components of the Reflex Arc 10 Fight or Flight Response 11  Central Nervous System Spinal cord Located in vertebrate spinal column. Limited analysis and decision making. Transmits information to and from the brain. Brain Located in the skull. Analyzes sensory information and makes appropriate responses. 12  Central Nervous System The Brain Weighs only about 1400 grams (2% of the average body weight). Complex structure is folded into gyri (hills) and sulci (valleys). Why is it folded like this? 13 14 Hindbrain (Rhombencephalon) Metencephalon Pons: sensory relay Cerebellum: maintaining posture, timing, planning movements, etc... Myelencephalon Medulla: controls basic life functions, e.g. breathing, heart rate, vomiting, etc. The medulla contains part of the reticular formation (reticular activating system) which plays a role in arousal and sleep regulation. 15  Midbrain (Mesencephalon) Mesencephalon Tectum (roof): contains the superior colliculus which control eye movements and the inferior colliculus which handles auditory information. Tegmentum (floor): contains part of the reticular formation, the substantia nigra which releases dopamine, the red nucleus which controls body movements. What happens if there is a problem with the substantia nigra that prevents it from producing enough dopamine? 16 Brainstem The brainstem consists of the hindbrain (metencephalon and myelencephalon) as well as the midbrain (mesencephalon). 17  Diencephalon Thalamus: a central relay station consisting of: Lateral Geniculate Nucleus (LGN): visual processing Medial Geniculate Nucleus (MGN): auditory processing Hypothalamus: involved in homeostatic control Pituitary gland: involved in hormonal control (master gland) Pineal gland: releases melatonin and is involved in sleep-wake cycle. 18  Telencephalon I: Limbic System The Limbic System: governs emotions such as anger, happiness, and fear and is involved in the storage and retrieval of memories. Includes hippocampus and amygdala. 19 Telencephalon II: Basal Ganglia Basal Ganglia Have widespread connections to the cortex and forebrain and are involved in the initiation of voluntary movements, maintaining muscle tone and posture Contain the caudate nucleus, the putamen, and the globus pallidus. The caudate nucleus and the putamen are referred to as the striatum due to their striped appearance. 20 Telencephalon III: Neocortex Occipital lobe—primary function is the analysis of visual information Parietal lobe—processes sensory information and is involved in spatial perception. Temporal lobe—processes auditory information and language (Wernicke’s area) Frontal lobe—motor programming, complex intellectual functioning, speech production (Broca’s area), personality, and executive function. 21  Cortical Homunculus Somatosensory and motor cortices have a physical representation of the body Wilder Penfield (1891-1976) 22 The Ventricular System 23  The Vascular System ~400 miles of blood vessels 24 The Vascular System 25