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Learn about the anatomical divisions of the nervous system, including the central nervous system (CNS) and peripheral nervous system (PNS). Explore the functions of the nervous system, types of neurons, membrane potential, action potential, synapses, and neurotransmitters. Understand the role of the meninges and cerebrospinal fluid in protecting the brain. Discover the different regions of the brain and their functions. Gain knowledge about common brain injuries, cerebrovascular accidents, and degenerative brain diseases.
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NS & Brain Ch 11
Anatomical Divisions of the Nervous System Central Nervous System (CNS) • brain • spinal cord Peripheral Nervous System (PNS) • cranial nerves • spinal nerves
CNS PNS
Function of the Nervous System sensory input motor input sensory receptor effector integration
Typical Neuron dendrite cell body Myelin sheath Synapse axon
Types of Neurons bipolar eye, ear, & olfactory unipolar Dorsal root ganglion cells multipolar most abundant type in CNS
Neuron Membrane Outside cell Na+ -70mV K+ Inside cell
Synapses Ca2+ Presynaptic neuron Postsynaptic membrane Synaptic vesicles containing neurotransmitters
Neurotransmitters • Acetylcholine- slows heart rate; PNS • Glutamate- most prevalent neurotransmitter in the brain • Aspartate- in CNS • GABA- inhibitory neurotransmitter • Glycine- inhibitory neurotransmitter • Norepinephrine- awakening from deep sleep • Epinephrine- increase heart rate • Dopamine- movement of skeletal muscles • Seratonin- sensory perception, temp regulation, mood, sleep • Nitric oxide- may play a role in memory and learning • Enkephalin- inhibit pain impulses by suppressing release of substance P • Substance P- enhances perception of pain tyrosine
skin skull dura mater arachnoid layer pia mater cerebral cortex Coverings of the Brain-Meninges
Menenges: • Covers and protects CNS • Protects blood vessels and encloses venus sinuses • Contains CSF • Forms partition within the skull
Cerebruspinal Fluid Brain Ventricles CSF Spinal Cord Lf. Ventricle Rt. Ventricle Saggital View Anterior View
CSF • 150 ml in adult • contains: glucose, proteins,lactic acid, urea, cations, anions, WBC • Functions: • Reduces wt. of brain by 97% • Prevents head injury • Supplies brain with nutrition • Transports hormones along ventricular channels
Cerebrum Parietal Lobe Frontal Lobe Temporal Lobe Occipital Lobe
cerebrum corpus callosum thalamus hypothalamus pituitary pons medulla oblongata spinal cord Pineal gland mid brain cerebellum
Cerebrum • Involved with higher brain functions. • Processes sensory information. • Initiates motor functions. • Integrates information.
Motor, Sensory & Association Cortex Primary motor cortex Primary somatosensory cortex Premotor cortex Wernicke’s Area speech Frontal association area speech taste reading hearing smell vision Broca’s Area Primary Auditory cortex Primary visual cortex
Max Fig. 49-17 Seeing words Hearing words Min Speaking words Generating words
Right-Left Specialization of the Cerebrum left side • language development • mathematical & learning capabilities • sequential thought processes right side • visual spatial skills • musical and artistic activities • intuitive abilities
The Limbic System The Limbic System
Thalamus • Relay center for sensory tracts from the spinal cord to the cerebrum. • Contains centers for sensation of pain, temperature, and touch. • Involved with emotions and alerting or arousal mechanisms.
Hypothalamus Regulates: • autonomic control center- blood pressure, rate and force of heart contraction, center for emotional response and behavior • body temperature • water balance and thirst • sleep/wake cycles • appetite • sexual arousal • control of endocrine functioning: • Acts on the pituitary gland through the release of neurosecretions.
Midbrain • Contains ascending and descending tracts to the cerebrum and thalamus. • Reflex center for eye muscles. • Also involved with processing visual and auditory information (connects head movements with visual and auditory stimuli).
Pons • Connects the two halves of the cerebellum. • Regulates breathing.
Medulla Oblongata • Composed of nerve tracts to and from the brain (these tracts cross over left to right and right to left) • May be regarded as an extension of the spinal cord • Almost all of the cranial nerves arise from this region
Medulla Oblongata • Contains control centers for many subconscious activities • Respiratory rate • Heart rate • Arteriole constriction • Swallowing • Hiccupping • Coughing • Sneezing
Cerebellum • Controls and coordinates muscular activity. • Important in equilibrium, posture and movement.
Traumatic Brain Injuries • Concussion • Contusion • Subdural or subarachnoid hemorrhage • Contrecoup injury • Punch Drunk Syndrome
Cerebrovascular Accidents (CVAs) • Ischemia • Thrombus • Embolism • Arteriosclerosis • Stroke
Degenerative brain diseases • Alzheimer’s • Down’s • Parkinson’s • Huntington’s Chorea • MS • Epilepsy • Schizophrenia
Normal Alzheimer’s
Normal Alzheimer’s Extreme shrinkage of cortex Cerebral cortex Severely enlarged ventricles Extreme shrinkage of hippocampus Hippocampus Entorhinal cortex
Normal Alzheimer’s
Down’s syndrome Problems in using spatial and contextual to form new memories: a function of the hippocampus Effects transmission of neurons between the locus coeruleus and hippocampus Scientists may have cure for Down’s http://www.sciencedaily.com/releases/2013/07/130717132330.htm