Overview of the Nervous System PDF

Fundamentals of Human Anatomy Nervous System and Physiology Dr Anna Gould Overview Intended Learning Outcomes 1. Describe the functions of the nervous system 2. Describe the organisation of the nervous system 3. Identify the major parts of...

Fundamentals of Human Anatomy Nervous System and Physiology Dr Anna Gould Overview Intended Learning Outcomes 1. Describe the functions of the nervous system 2. Describe the organisation of the nervous system 3. Identify the major parts of the brain 4. Describe the gross anatomical features of the spinal cord 5. Describe the protective structures of the brain and spinal cord  Controls the body’s internal environment to maintain homeostasis Functions Allows for experience and of interpretation of a range of sensations Nervous System Controls all voluntary movements and mediates automatic reactions Responsible for perceptions, behaviours and memories  Peripheral Nervous System Somatic Nervous System (SNS) SNS consists of: Somatic and special sense receptors Sensory neurons – carries impulses from receptors to CNS Motor neurons – carries impulses from the CNS to skeletal muscles Motor response to a sensory stimulus Pause: Can you think of any examples? Afferent - sensory neurones carry information from cranial and spinal nerves to CNS or from a lower to a higher level in the CNS Integrative – interneurones integrate and analyse sensory information and decide on action Efferent – motor neurones carry information from brain to Spinal Cord or from CNS to cranial or spinal nerves Effectors – Muscle fibres and glands Autonomic Nervous System The Central Nervous System The human brain Your amazing brain… Most complex organ in your body Contains 86 billion neurons 10 to 50 trillion neuroglia On average, each neuron forms 1000 synapses with other neurons PHOTOGRAPH BY FRED HOSSLER/GETTY IMAGES Major parts of the brain Corpus Callosum Cerebrum Cerebrum consists of: 1. An outer cerebral cortex 2. Internal region of cerebral white matter 3. Grey matter nuclei deep within the white matter – Basal Ganglia  PHOTOGRAPH BY FRED HOSSLER/GETTY IMAGES Hills/Peaks Gyri Valleys/troughs Fissures (deep) Sulci (shallow) Longitudinal Fissure Squire, 2008 Central Sulcus Primary Motor Area/ Primary Somatosensory Area/ Lobes of the cerebrum  Frontal Lobe – responsible for What do movement but also associated with reasoning, planning, motor each of aspects of speech, emotions, these and problem solving. Short term/working memory. lobes Parietal Lobe - associated do? with the perception of sensory stimuli, orientation and recognition. Occipital Lobe - associated with visual processing Temporal Lobe - associated with perception and recognition of auditory stimuli, memory (long term) and receptive language.  “He had become fitful, irreverent, grossly profane, and showed little deference for other workers. Impatient and obstinate yet capricious and vacillating, he was unable to proceed with any plans”.  Basal Ganglia Group of brain structures located underneath the cerebral cortex but on top of the brainstem  Diencephalon: Thalamus Located in the middle of the brain at the base of the cerebrum, below the cerebral cortex and above the midbrain Brainstem Midbrain Pons Medulla Oblongata AnatomyTV Continuous with spinal cord below and diencephalon/cerebrum above Cerebellum Found just below the cerebrum and behind the pons Involved in the co-ordination of movement and motor learning amongst other functions  Ventricles Ventricles consist of four cerebrospinal fluid (CSF) filled cavities within the brain One lateral ventricle projects forwards into each hemisphere of the cerebrum (1 and 2) The third ventricle sits between the right and left halves of the thalamus The fourth ventricle lies between the brainstem and the Clinical Application: Hydrocepha lus Abnormal build up of fluid in the ventricles In infants, it can be cause by blocked cerebral aqueduct Causes the ventricles to widen, putting pressure on the brain’s tissues – can cause brain damage or death Shakeel et al., 2019  Spinal Cord Carries incoming and outgoing messages between the brain and the rest of the body. 100 million neurons and even more neuroglia compose the spinal cord Extends from the brain stem (medulla) to the second lumbar vertebra Tortora, p240  Transverse section through the spinal cord  Motor/ Efferent Sensory/ (descending Afferent ) tract (ascending) tract 7. Anterior horn cell Tortora, p.568 Cardiac muscle, smooth muscle and Protective structures: Meninges Meninges are three membranes that cover the brain and spinal cord Outermost D Dura Mater A Arachnoid P Pia Mater Innermost https://www.youtube.com/watch?v=CIkgQcmv0Xs Intended Learning Outcomes 1. Describe the functions of the nervous system 2. Describe the organisation of the nervous system 3. Identify the major parts of the brain 4. Describe the gross anatomical features of the spinal cord 5. Describe the protective structures of the brain and spinal cord Further reading Tortora’s principles of anatomy and physiology Chapter 14 The Brain and Cranial Nerves (14.1 – 14.7) Chapter 13 The Spinal Cord and Spinal Nerves (13.1)