Nervous System Part 3 PDF

Nervous System Part 3 Central Nervous System & Peripheral Nervous System Tutor Debbie Hemington Module BMS GDC Learning outcomes As for parts 1 & 2 Intended learning outcomes At the end of the session, you will be able to: Describe the 2 parts of the nervous system List the ke...

Nervous System Part 3 Central Nervous System & Peripheral Nervous System Tutor Debbie Hemington Module BMS GDC Learning outcomes As for parts 1 & 2 Intended learning outcomes At the end of the session, you will be able to: Describe the 2 parts of the nervous system List the key features of the human brain and spinal cord Describe the main areas of the brain and their func=on List the func=ons of cerebrospinal >uid List the groups of spinal nerves Assessment Forma=ve Summa=ve Short answers End of module exams MCQ The central nervous system Brain and spinal cord Brain Weighs around 1.4kg Lies in cranial cavity Comprises of: (Different areas) Cerebrum Thalamus Hypothalamus Mid brain Pons Medulla oblongata Cerebellum Cerebrum Largest part of the brain 3 main func=onal areas associated with; Mental Ac=vi=es-memory, intelligence, problem solving, re>ec=on, judgement, thinking, reasoning, ini=a=ve, inhibi=on, moral sense of responsibility and learning Sensory percep=on-percep=on of pain, temperature and touch Ini=a=on and control of voluntary muscle contrac=on The Cerebrum The outer later The cerebral cortex is highly wrinkled, which makes the brain more eScient, because it can increase the surface area of the brain and the amount of neurons within it. A deep furrow divides the cerebrum into two halves, known as the leT and right hemispheres. The corpus callosum is a bundle of axons which connects these two hemispheres.  Located just above the brain stem between cerebral cortex and the mid brain. Extensive nerve connections to both. Thalamus Main function - relay sensory and motor signals to cerebral cortex. Small structure Sensory receptors in skin & viscera send info about touch, pain & temperature Input from the special sense organs travels here too where there is percep=on but only in basic form Thought to be involved in arousal and the processing of some emo=ons and complex re>exes Thalamus Hypothalamus Situated within the cerebrum AVached to the pituitary gland Controls the output of hormones Controls eHectors of the autonomic nervous system: Emo=onal reac=ons Hunger and thirst Body temperature Biological clocks Mid brain Consists of nuclei and nerve Xbres which connect the cerebrum with the lower parts of the brain and spinal cord. Nuclei act as relay sta=ons for the ascending and descending nerve Xbres and have important roles in auditory and visual re>exes. Pons Contains nerve Xbres, which form a bridge between the two hemispheres of the cerebrum Processes info from several of the cranial nerves  Coordinates voluntary muscle movement. Medulla Oblongata Important and posture and balance and smooth movements. Proprioceptor impulses received here. Proprioceptor is a sensory receptor - receives stimuli from within body - especially position and movement. Is con=nuous with the spinal cord Controls eHectors: Controls vital senses of the body which are responsive to autonomic reflex activity. cardiovascular centre respiratory centre re>ex centres: coughing, vomi=ng, sneezing, swallowing Spinal Cord Nerves conveying impulses from the brain to various organs and =ssues descend through it. Starts in the medulla oblongata and descends through the spinal column.. Spinal cord Elongated, almost cylindrical part of the CNS. Suspended in the vertebral canal Surrounded by meninges & cerebro-spinal >uid Approx the thickness of a liVle Xnger Approx 45cms long Cerebrospinal Juid Cerebrospinal Juid (CSF) is a clear colourless >uid that: occupies the subarachnoid space in the brain acts as a "cushion" or bu_er for the cortex is renewed 4 =mes daily contains proteins, glucose and lymphocytes FuncLons of Cerebrospinal Fluid Protec=on Buoyancy Excre=on of waste products Endocrine medium for the brain. ProtecLon The CSF protects the brain by ‘bu_ering’ the brain. This lessens the impact when there is a blow to the head. Image sourced April 2021 Dreamstime.com Buoyancy Because the brain is immersed in >uid, the net weight of the brain is reduced from about 1400g to about 50g, thus reducing the pressure at the base of the brain. Image sourced April 2021 Q Files ExcreLon of waste products The one-way >ow from the CSF to the blood takes poten=ally harmful metabolites, drugs and other substances away from the brain Image sourced April 2021 Depositphotos Endocrine medium for the brain The CSF serves to transport hormones to certain areas of the brain. Hormones released into the CSF can be carried to remote sites of the brain where they may act. Image sourced April 2021 SubPNG The Peripheral Nervous System Peripheral Nervous System Voluntary Involuntary (heart rate, digestion) Image sourced April 2021 Biology Libre Texts. Autonomic Nervous System The sympatheLc nervous system ac=vates the “Qght or Jight” response during a threat or perceived danger Needed for short term survival The parasympatheLc nervous system restores the body to a state of calm, the “rest and digest” phase Needed for long term survival. Cranial Nerves 12 pairs Origin on inferior surface of the brain - mainly brain stem Some sensory, some motor or mixed Names suggest distribution or function Generally relate to head and neck  Spinal Nerves 31 pairs Leave the spinal canal passing through intervertebral foramina Leaves a small opening between every vertebrae Names according to vertebrae associated with. 8 cervical 12 thoracic 5 lumber 5 sacrum 1 coccyx Intervertebral Foramina Peripheral Nerves Useful links Autonomic Nervous System: Sympathe=c vs Parasympathe=c, Anima=on – YouTube 2-Minute Neuroscience: Divisions of the Nervous System – YouTube