309D S08 Exam 2 Checklist-F

309D S08 Exam 2 Checklist-F - Bio 309D: Exam #2 Review...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Bio 309D: Exam #2 Review Checklist Friday, March 28 Chapter 7: pages 111-119 Nervous system Neuriglial cell (glial cell) more numerous Functions does not participate in transmission of electrical signals; support neurons Schwaan cell forms myelin sheath by wrapping around the axon many times Neuron functional unitys of nervous system Sensory (afferent) neuron carry info. toward CNHS from sensory neurons Interneuron (association neuron) integrate/interpret sensory signals & decide on appropriate response; most numerous Motor (efferent) neuron carry info. away from CNS to an effector (muscle/gland) Dendrite thin, branched processes; carry info. toward cell body; receiving position Cell body Axon long extension that branches near end into axon terminals; carries info. away from cell body; usually myelinated Axon terminals tip of a branch of an axon; releases a chemical (neurotransmitter) that alters activity of target cell Myelin sheath insulating outer layer around axons Functions speeds up conduction of electrical signal down azxn; helps in repair of damaged neurons Structure composed of plasma membrane of Schwann cells that wrap around axon Node of Ranvier gap between Schwann cells; impulses jump from one node to the next Nerve bundle of parallel axons from many neurons; covered w/tough connective tissue Sensory nerve contains sensory neurons Motor nerve contains motor neurons Mixed nerve Nerve impulse/signal Membrane potential difference in charge across membrane; due to distribution of ions Ion channel (gated) hydrophilic pores in membrane through which ions can pass w/o input of energy Sodium-potassium pump (Na + -K + pump) carrier proteins actively transport Na+ & K+ ions across membrane; 3 Na+ Resting membrane potential membrane potential of neuron not transmitting signal; -70mV Resting ion distribution: Na+ and K+ inside negative compared to outside; outside high [Na+], low K+] Electrical signal created by ion movements across membrane Graded potential transient local changes in membrane potential; magnitude of change varies w/strength of stimulus Hyperpolarization makes cytoplasm more negative Depolarization makes cytoplasm more positive; caused by inward flow of positively charged Na+ ions Action potential triggered when depolarization reaches threshold value Rising phase (depolarization) opening of Na+ channels; Na+ enters cell; more positive membrane potential Falling phase (repolarization) K+ channels open; Na + channels close; K+ exits cell; more negative membrane potential All-or-nothing intensity of signal does not vary w/strength of stimulus that triggered it Conduction movement of action potential through axon; occur sequentially along length of axon; do not diminish Synaptic transmission change form electrical signal to chemical signal when action potential reaches end of axon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

309D S08 Exam 2 Checklist-F - Bio 309D: Exam #2 Review...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online