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Nervous system overview (48.1). Sensory Input Transmit information Light, sound, touch, heat smell, taste, etc Integration CNS (central nervous system) Brain and nerve cord analyzes and interprets Motor Output PNS (peripheral nervous system) carries information into and out of CNS - PowerPoint PPT Presentation
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Nervous system overview (48.1)
• Sensory Input– Transmit information
• Light, sound, touch, heat smell, taste, etc
• Integration– CNS (central nervous system)
• Brain and nerve cord analyzes and interprets
• Motor Output– PNS (peripheral nervous system)
• carries information into and out of CNS
• Transmission triggers an activity or causes an effect such as muscle contraction
Fig 48.3
• Neural cell/Neuron– Branched dendrites
• Receive signals from other neurons
• Shorter, highly branched– Single axon
• Transmits signals to other neurons
• Longer– Synaptic terminals (fig 48.4)
• Axons / dendrite junctions• Pass information through
chemical neurotransmitters– Glia
• Supporting cells to nourish, insulate, and regulate fluids
Brain and embryonic developmentAfter gastrulation…• Neural plate forms
– Dorsal orientation– “cephal to caudal” direction
• Neural tube forms– Infolding of plate, forming groove and
crest– Fuses to form tube– Cephal end enlarges = brain– Rest is spinal cord
• Mesoderm– Coelom formation– Somites give rise to segmented
structures• Endoderm
– Gastrovascular developmentFig 47.13
Continued brain development into multiple lobes, enlargements, and extensions
Fig 49.9
• Forebrain Cerebrum – Two hemispheres
• Left: logical, temporal, language• Right: Spatial, abstract, artistic, gestalt
(perceiving “whole” rather than parts)– Cerebral Cortex
• Outer gray matter– Highly infolded (high surface area)
• Sulcus (folds) between gyrus (tissue)• Increased s/a = more gray matter and
generally more intelligence– Lobes are connected by underlying
white matter• Corpus callosum is the main L/R
connection
– Frontal lobes• Primary motor cortex (motor skills),
muscle control, speech, smell, memory, and integration from other areas
– Parietal lobes• Somatosensory, touch, pressure stimuli
– Temporal lobes• Hearing, balance
– Occipital lobes• Visual centers (visualizing an event or
how to spell something)
• Thalamus– Two egg-shaped masses– Cerebral sensory impulses and
emotional center (limbic system)• Along with Amygdala (fight or flight)
– Plays role in process:• Sensation, Motor activities, waking up,
learning, memory
• Hypothalamus– Connects to pituitary
• Stores hormones for regulation in endocrine system
– Homeostatic control functions• Autonomic controls, physiological
emotions, body temp., thirst and satiety, circadian rhythms
• Midbrain– White matter masses connects to
cerebrum and cerebellum– Visual and auditory reflex centers
• HindbrainBrain stem and cerebellum– Pons connects upper and lower center
• Respiratory center with hypothalumus
• Cerebellum• Athletic brain: refining and directing motor
activities• “athletic memory”
• Medulla oblongata• Autonomic reflexes: cardio regulatory, blood
pressure, respiratory, vomiting, couching
Brain ventricles and CSF• Ventricles are remnants
of early hollow tube• Filled with Cerebral
Spinal Fluid– Derived from blood
plasma; with lots of ions– Liquid cushion– “fatty” brain mass
“floats”, protected, supported, w/o rigid or sharp edged structures
Meninges
Meninges 2
Reflex arc
Peripheral Nervous System – radiates to and from CNS & includes Somatic (SNS) and autonomic (ANS)Somatic: mechanoreceptors, pain, chemo-, photo-, thermoreceptorsAutonomic: unconscious visceral reception; antagonistic (opp. Effects)
ANS Sympathetic ANS Parasympathetic
Taste/smell
Eye
Eye from text
Ear
• Malleus (hammer)
• Incus (anvil)
• Stapes (stirrup)
Cochlea
Cochlea2
Basilar/Tectorial Membrane
Saccule/Utricle
Vestibular apparatus
Macula with Otoliths
Cupula of semicircular canal