Nervous system: The Central Nervous System PDF

Nervous system: the central nervous system Paul Austin School of Medical Sciences https://www.theguesthouseocala.com/ Structure of the nervous system The central nervous system is made up of the brain the spinal cord The peripheral nervous system is made up of the cranial nerves the spinal nerves Th...

Nervous system: the central nervous system Paul Austin School of Medical Sciences https://www.theguesthouseocala.com/ Structure of the nervous system The central nervous system is made up of the brain the spinal cord The peripheral nervous system is made up of the cranial nerves the spinal nerves The University of Sydney Arrangement of the nervous system The University of Sydney Arrangement of the nervous system The University of Sydney The Brain The forebrain The largest region. Contains the cerebral cortex and the thalamus, hypothalamus, pineal gland and limbic system within it. The hindbrain Includes the brainstem and cerebellum. The brainstem includes the midbrain, pons and the medulla oblongata. The midbrain connects the rest of the brainstem to the cerebral cortex. The pons is the “bridge” between the midbrain and medulla The medulla oblongata is where the brain transitions to the spinal cord. - Contains the respiratory and cardiovascular control centres. The University of Sydney The Cerebral Cortex The cerebral cortex is divided into right and left cerebral hemispheres. They are connected by the corpus callosum. Each of the hemispheres is divided into four lobes: frontal, parietal, temporal and occipital. The University of Sydney The Brain https://theconversation.com/explainer-the-brain-11196 The University of Sydney Cerebral hemispheres https://upload.wikimedia.org/wikipedia/commons/6/64/Coronal_cross-section_of_human_brain.jpg The University of Sydney https://ecampusontario.pressbooks.pub/conceptsbiocdnremediate/chapter/16-3-the-central-nervous-system/ Lobes of the cortex The University of Sydney https://qbi.uq.edu.au/brain/brain-anatomy/lobes-brain The functions of the lobes Frontal lobe The frontal lobe is generally where higher executive functions including emotional regulation, planning, reasoning and problem solving occur. Parietal lobe The parietal lobe is responsible for integrating sensory information, including touch, temperature, pressure and pain. Temporal lobe The temporal lobe is responsible for processing sensory information, and is particularly important for hearing, recognising language, and forming memories. Occipital lobe The occipital lobe is the major visual processing centre in the brain. The University of Sydney Other forebrain regions The thalamus processes sensory information. The hypothalamus is the major control centre of the autonomic motor system. It is involved in some hormonal activity and connects the hormonal and nervous systems. The hypothalamus also helps regulate homeostasis. The pineal gland produces the hormone melatonin, which regulates our sleep-wake cycles. Just like the hypothalamus, it is also involved in regulating hormonal functions. The limbic system regulates behavioural and emotional responses. Most important parts are the hippocampus and the amygdala. The basal ganglia are involved in including control of voluntary motor movements, habit learning, eye movements, cognition and emotion. The University of Sydney The cerebellum The cerebellum coordinates gait and maintains posture, controls muscle tone and voluntary muscle activity but is unable to initiate muscle contraction. The cerebellum receives information about voluntary muscle movements from the cerebral cortex and from the muscles, tendons, and joints. balance from the vestibular nuclei. Damage results in a loss in the ability to control fine movements, maintain posture, and motor learning. The University of Sydney Regions of the cerebellum The University of Sydney https://www.ncbi.nlm.nih.gov/books/NBK545251/figure/article-882.image.f1/?report=objectonly The brainstem The brainstem connects the forebrain to the spinal cord and cerebellum. Many ascending and descending tracts pass through the brain stem. It is responsible for many vital functions of life, such as breathing, consciousness, blood pressure, heart rate, and sleep. The University of Sydney The brainstem The University of Sydney Pathways through the CNS The University of Sydney The spinal cord Carries motor and sensory signals between the brain and periphery and coordinates reflexes. The spinal cord is organised into segments, with pairs of spinal nerves emerging from each segment. The University of Sydney Spinal cord The spinal cord is composed of grey matter and white The white matter is composed of fibre tracts of myelinated sensory and motor axons. Knowledge of where each tract is located, and what information it carries allows localisation of damage. The University of Sydney Decussation Sensory pathways decussate (cross-over) from one side of the CNS to the other. Each cerebral hemisphere receives sensory information from the opposite side of the body. Motor pathways decussate from one side of the CNS to the other. Each cerebral hemisphere controls the opposite side of the body. The University of Sydney Decussation Sensory pathways Motor pathway is perceived in right cerebral cortex Right cerebral cortex controls... left body movement The University of Sydney Left body sensation… Spinal nerves http://www.clipartbest.com/clipart-eiMyM7LRT The University of Sydney By KDS4444 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=53368293 Spinal nerves The University of Sydney https://www.cancer.org Abd-Elsayed A. (2019) Sacral Plexus. In: Abd-Elsayed A. (eds) Pain. Springer, Cham. https://doi.org/10.1007/978-3-319-99124-5_103 Peripheral nerves Large anatomical nerves are formed when spinal nerves coalesce. Large anatomical nerves are made up of many nerve fibres. Some are motor fibres Some are sensory fibres The University of Sydney Dermatomes The University of Sydney https://smart.servier.com/smart_image/dermatomes/ The Cranial Nerves The University of Sydney https://biologydictionary.net/cranial-nerves/ Autonomic nervous system The autonomic nervous system (ANS) functions without conscious control to maintain homeostasis. It controls cardiac muscle smooth muscle exocrine glands endocrine glands Divided into sympathetic - “fight or flight”, sympathetic nerves supply many tissues including the adrenal gland which releases adrenaline parasympathetic system - “rest and digest”, parasympathetic nerves supply many tissues The University of Sydney Summary Specific regions of the brain have specific functions. Different regions of the brain are linked to allow maximum functional integration. The linkages are by tracts (pathways). The brain is built layer on layer, with the most complex functions being controlled at the highest levels. Knowing the anatomy of the brain and the pathways allows accurate diagnosis of damaged areas in the brain. The University of Sydney