Nervous System

Chapter 49

• Organization correlates w/ lifestyle– Sessile molluscs w/ simple– Complex molluscs w/ complex

• Nerve net is connected nerve cells– Cnidarians to regulate gastrovascular cavity

• Nerves are bundles of nerve cells– Echinoderms w/ branched nerve nets– Bilateral animals w/ cephalization– Platyhelminthes w/ CNS– Arthropods and annelids w/ ganglia– Vertebrates w/ CNS and PNS

Comparative Nervous Systems

Vertebrate Nervous Systems

Nervous System

Central Nervous System (CNS)

Brain Spinal Cord

Peripheral Nervous System (PNS)

Motor (efferent)

Autonomic(involuntary)

Sympathetic Parasympathetic

Somatic

(voluntary)

Sensory (afferent)

Cerebral Hemispheres

• Demonstrate lateralization– Left: math, speech, concrete processing, logic– Right: creativity, facial and pattern recognition

• Contralateral control• Corpus callosum communicates• 4 lobes

http://faculty.washington.edu/chudler/split.html

Cerebral Lobes• Frontal

– Reasoning, planning, personality, problem solving– Process emotional and painful info– Voluntary mov’t– Learned planned activities

• Parietal (2)– Sensory information– Integrating sensory and motor

• Temporal (2)– Auditory senses and memory– Broca’s and Wernicke’s area (left)

• Occipital– Visual information

Other Brain Anatomy

• Olfactory bulb• Brainstem

– Hindbrain• Basic life processes

– Respiration– Heart rate– Emesis

• Cerebellum– Coordination and balance– Proprioceptive input

– Midbrain• React to visual and auditory stimuli• Optic lobes in non-mammal vertebrates

– Reticular formation

• Relative brain size– Animals– Male/female

• Cerebral cortex– Cortical folding– Mammals increase association

areas• Complex behavior and learning

• Cerebellum– Cat/dog

• Olfactory bulb• Limbic system w/avoidance

Comparative Brain Anatomy

Arousal and Sleep

• Reticular formation– Sensory filter for info into cerebral cortex

• More info = more alert• Selective attention

– LSD, sleep, alcohol inhibits• Pineal gland w/ melanin

– From 5-HT from tryptophan– Peak at night– Signal sleep stimulate areas

• Essential for survival• Dolphins 1 hemisphere at a time