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Neural Control
Nervous System
 Functions (Neurons)
 Sensory input


Detect & receive
Internal or external
 Integration

Process & interpret
 Motor output

Muscles & glands
Nerve Pathway
Stimulus
Response
Sensory
Neurons
Interneurons
Effectors
Motor
Neurons
Nervous System Types
 Nerve Net
 Cnidarians
 Sensory neurons in epidermis
 Motor neurons in all tissues
Nervous System Types
 Ladder-Like
 Plathyhelminthes
 Long nerves
 Ganglia (“brain”)

Integration
Nervous System Types
 Advanced Invertebrates
 More advanced
 Cephalized
 Brain
 Ventral nerve cord
 Branching nerves
Nervous System Types
 Vertebrate
 More advanced
 Many more neurons


1 million in insects
Vertebrates 1,000-1
billion more!
 Two divisions


Central nervous system
Peripheral nervous
system
Nerve Cells
 Neuron
 Primary cell type
 Conducts impulses
 Neuroglial
 Support/nourish neuron
 Non-excitatory
 9:1 ratio
Neuroglial Cells—CNS
Neuroglial Cells—PNS
Neurons
 Characteristics
 Excitable
 Longevity
 High Metabolic Rate
 Sometimes Large
 Amitotic
 May Regenerate
Neurons
 Sensory (afferent)
 Detects stimuli
 Carry signal to CNS
 Interneuron (association)
 Transmit between neurons in CNS
 Motor (efferent)
 Carry signal to muscle or gland
Neurons
 Axon
 Soma
 Dendrite
 Myelin sheath
 Axon terminal
 Synapse
Neurons
 Myelin Sheath
 Insulating
 Myelinated transmit faster
Neurons
 Synapse
 Chemical
 Electrical
Neurotransmitters
 Acetylcholine
 Most common
 Neuromuscular junction
 Norepinephrine
 Involuntary functions
 Dopamine
 Many functions
 Behavior & mental ability
 Serotonin
 Mood
 Sleep
Nerve Impulse
 Resting potential
 Na+ higher outside of cell
 K+ higher inside of cell
Nerve Impulse
Nerve Impulse
Nerve Impulse
 Sodium gates open
 Sodium moves into cell
 Action potential starts
 Potassium gates open
 Potassium moves out of cell
 Electrical charges across
membrane switch
 “Wave” of charge moves along
axon
Nerve Impulse
 Myelinated axons transmit signal faster
Nerve Impulse
 All-or-nothing
 Refractory period
 Cannot respond to signal
Central Nervous System
 Brain & spinal cord
 White matter—myelinated
 Grey matter—unmyelinated
 Meninges
 Cerebrospinal fluid
Central Nervous System
 Brain
 Alligator—0.003% body weight
 Sperm whale—0.06%
 Rat—0.5%
 Human—2%
Brain
 Cerebrum
 Integrates & analyzes
 Frontal lobe—motor control
 Parietal lobe—sensory from body
 Occipital lobe—vision
 Temporal lobe—hearing, emotions
Brain
 Thalamus
 Relay station
 Memories, emotions
 Hypothalamus
 Homeostasis
 Sleep, sex, thirst, etc.
 Medulla Oblongata
 Heart rate, breathing, blood pressure
 Involuntary muscle contractions
Brain
 Pons
 Fine-tune breathing
 Hearing/sight reflexes
 Cerebellum
 Coordinate movement
 Gordon
 Weebles
Brain
 Limbic System
 Learning
 Memory
 Fear & pleasure
 Facial expressions
Peripheral Nervous System
 Cranial & spinal nerves
Peripheral Nervous System
 12 pairs Cranial Nerves
 31 pairs Spinal Nerves
Peripheral Nervous System
 Somatic
 Sensory signals to skeletal muscle
 Synapses in brain or spinal cord
 Reflexes
Peripheral Nervous System
 Reflex arc
Peripheral Nervous System
 Autonomic
 Involuntary
 Cardiac muscle
 Smooth muscle
 Glands
Autonomic Nervous System
 Sympathetic
 “Fight or flight”
 Excitement
 Exercise
 Emergency
 Embarassment
 Parasympathetic
 “Rest & digest”
 Digestion
 Defecation
 Diuresis
Autonomic Nervous System
Organ
Parasympathetic
Sympathetic
Eye (pupil)
Constrict
Dilate
Glands
Stimulates secretion
Inhibits secretion
Heart muscle
Slows & steadies rate
Increases rate & force
Lungs
Constricts bronchioles
Dilates bronchioles
Digestive tract
Increases digestion
Decreases digestion
Bladder
Promotes voiding
Inhibits voiding
Mental activity
No effect
Increases alertness
Autonomic Nervous System
Autonomic Nervous System