Nervous SystemsChapter 48

Kate McAteer

Organization of Nervous Systems48.1

Invertebrate nervous systems range in complexity from nerve nets to brains and nerve cords

Vertebrates have a central nervous system (brain and spinal cord) and a peripheral nervous system

Information Processing48.1

PNS nerves transmit sensory and motor signals

CNS integrates information Nervous systems process info in 3

stages: Sensory Input Integration Motor output to effector cells

Neuron Structure48.1 Dendrites Axon Variety of shapes

Ion Pumps and Ion Channels48.2 Membrane potential

Resting potential

Nerve impulses

Hyper/De – Polarization + Action Potential

48.3 Hyperpolarization: increase in

magnitude of membrane potentialVs. Depolarization: decrease… Action potential: brief ‘all or none’

depolarization of a neuron’s plasma membrane

Direct Synaptic Transmission48.4 Neurotransmitter binds to gated ion

channels in the postsynaptic membrane, producing an EPSP or IPSP

After release, neuro. is taken up by surrounding cells or is degraded by enzymes

Single neuron has many synapses on its dendrites and cell body

Indirect Synaptic Transmission48.4

Binding of a neurotransmitter to some

receptors activates signal transduction

pathways , which produce slowly

developing but long lasting effects in

the postsynaptic cell

Neurotransmitters48.4 Same neurotransmitter can produce

different effects on different types of cells

Well known: acetylcholine, biogenic amines, various amino acids and peptides, some gases

PNS48.5 Consists of paired cranial

and spinal nerves and associated ganglia

Divided into somatic nervous system and autonomic nervous system (3 divisions: the sympathetic and parasympathetic divisions and enteric division)

Embryonic Development of Brain48.5 Vertebrate brain develops from 3

regions: Forebrain (most expansive growth) Midbrain Hindbrain

Brainstem + Cerebrum48.5 Cerebrum:

Two hemispheres which are important in learning and planning

Brainstem: Controls homeostatic functions such as

breathing rate, sensory and motor signals, and regulates arousal and sleep

Medulla oblongata, Pons, Midbrain

Cerebellum + Diencephalon48.5 Diencephalon:

Thalamus is main center Hypothalamus maintains homeostasis and

basic survival behaviors Cerebellum:

Helps coordinate motor, perceptual, and cognitive functions

Involved in learning and remembering motor skills

Four Lobes48.6 Frontal

Essential for understanding

language Temporal

Essential for understanding language

Occipital Parietal

Diseases48.7 Schizophrenia (hallucinations)

Depression (incl. bipolar disorder)

Alzheimer’s (senile plaques form in brain)

Parkinson’s (death of dopamine secreting neurons)

Sourceshttp://qwickstep.com/search/four-brain-lobes.htmlhttp://www.google.com/imgres?imgurl=http://http://www.google.com/imgres?imgurl=http://sciencecity.oupchina.com.hk/biology/student/glossary/img/peripheral_nervous_system.jpghttp://qwickstep.com/search/structure-of-neuron.htmlhttp://www.google.com/imgres?imgurl=http://