Nervous System Lecture Notes PDF

Structure of the Nervous system Textbook Chapter 49 https://pollev.com/barbaraakum216 1 Topics to cover A. Organisation of the nervous system B. Hierarchy of the vertebrate nervous system C. The Central Nervous system D. The Peripheral nervous system E. Nerv...

Structure of the Nervous system Textbook Chapter 49 https://pollev.com/barbaraakum216 1 Topics to cover A. Organisation of the nervous system B. Hierarchy of the vertebrate nervous system C. The Central Nervous system D. The Peripheral nervous system E. Nervous System disorders 2 Complex nervous system: Organisation Central nervous system (CNS), where integration takes place; ○ Brain or simpler clusters called ganglia ○ Spinal cord Peripheral nervous system(PNS), which carries information into and out of the CNS Neurons of both the CNS and PNS require supporting cells called glial cells, or glia 3 4  Functional hierarchy of the vertebrate nervous system CENTRAL NERVOUS SYSTEM CNS (information processing) PERIPHERAL NERVOUS SYSTEM Afferent neurons Efferent neurons Autonomic Motor system Sensory nervous system PNS receptors Control of skeletal muscles Enteric nervous Internal Sympathetic Parasympathetic system and external division division stimuli Control of smooth muscles, cardiac muscles, glands Figure 49.8 5 C. The Central Nervous System Figure 49.11 6 Brain and Information processing Figure 49.16 Each of the four lobes of the cerebral cortex has specialized functions, some of which are listed here. Some areas on the left side of the brain (shown here) have different functions from those on the right side (not shown) 7 The Spinal Cord - A reflex The spinal cord conveys information to and from the brain and generates basic patterns of locomotion The spinal cord also produces reflexes independently of the brain A reflex is the body’s automatic response to a stimulus –For example, a doctor uses a mallet to trigger a knee-jerk reflex 8 The Spinal Cord and the knee-jerk reflex Figure 49.5 9 D. The Peripheral Nervous System Transmits information to and from the CNS and regulates movement and the internal environment Two types of neurons ○ Afferent neurons transmit information to the CNS ○ Efferent neurons transmit information away from the CNS https://anatomytool.org/content/cenveo-drawing-efferent-neurons-afferent-neurons-and-interneurons-english-labels 10 The Peripheral Nervous System Two efferent components: ○ motor system ○ autonomic nervous system The motor system carries signals to skeletal muscles and can be voluntary or involuntary The autonomic nervous system regulates smooth and cardiac muscles and is generally involuntary ○ Sympathetic - regulates arousal and energy generation (“fight-or-flight” response) ○ Parasympathetic - antagonistic effects on target organs and promotes calming and a return to “rest-and-digest” functions The enteric nervous system exerts direct, partially independent, control over the digestive tract, pancreas, and gallbladder 11 Motor and autonomic nervous system pathways Figure 49.8 12 The autonomic nervous system 13 D. Nervous system disorders Schizophrenia Depression Alzheimer’s disease Parkinson’s disease Drug addiction 14 Schizophrenia Severe mental disturbance Characterized by psychotic episodes in which patients have a distorted perception of reality Strong genetic component Neuronal pathways that use dopamine as a neurotransmitter are disrupted in schizophrenia Image credit: Nature Reviews Neurology volume 20, pages 22–35 (2024) 15 Depression Depressed mood, abnormalities in sleep, appetite, and energy level Two major types: major depressive disorder and bipolar disorder (manic-depressive disorder) Neuronal pathways that use monoamine (Serotonin) as a neurotransmitter are disrupted Drugs: fluoxetine (Prozac), increase activity of biogenic amines in the brain. NORMAL DEPRESSION PROZAC TREATED Image credit: https://www.open.edu/openlearn/health-sports-psychology/health/understanding-depression-and-anxiety/content-section-4.1 16 Alzheimer’s Disease Mental deterioration (dementia) characterized by confusion and memory loss The incidence of Alzheimer’s disease increases with age It is associated with formation of amyloid plaques and neurofibrillary tangles in the brain There is also massive shrinkage of brain tissue, reflecting the death of neurons in many areas of the brain A hallmark of Alzheimer’s disease is the presence in brain tissue of neurofibrillary tangles surrounding plaques made of B-amyloid (LM) 17 Alzheimer’s Disease Amyloid plaques disrupt cell-to-cell communication 18 Parkinson’s Disease Motor disorder: muscle tremors, poor balance, a flexed posture, and a shuffling gait Death of dopamine-secreting neurons in the midbrain The incidence increases with advancing age A dopamine-related drug called L-dopa can reduce the severity of Parkinson’s disease symptoms Image Source: anti-agingfirewalls.com 19 Effects of addictive drugs on the reward system Nicotine Inhibitory neuron Opioids Dopami ne- releasin g Cocaine VTA neuron Figure 49.24 20