BIOC32H3 Study Guide - Fall 2018, Comprehensive Midterm Notes - Membrane Potential, Electrophysiology, Neuron
BIOC32H3
MIDTERM EXAM
STUDY GUIDE
Fall 2018
BIOC32- Human Physiology
Neurons and Electrophysiology
Lecture 1
• Structure
o Many kinds of neurons in the mammalian brain- some are small, some are large, different
shapes/structures
o Basic structural elements of neuron
▪ Dendrites: there can be many dendrites and they serve to collect neural impulses to
cell body (bring info from tips to body). Dendritic spine stick out of dendrites (when
other neurons interact with dendrites, interaction occurs at the spine)
▪ Axon: just 1 axon per neuron. They send signals out to other types of cells- single
neuron can send out 1 signal (either sending or not sending signal). They branch
(collateral branches far from terminal end and allows for 1 signal to be carried far
away in body)
▪ Axon terminal: at end of each terminal
branch that interacts with adjacent cell
to give signal
▪ Cell body: where you find organelles of
neuron (dense regions called Nissl
substance- dark areas- were actually RER
and 3 ribosomes- meaning neurons must
make lots of protein and use them in
membrane)
o Axons vary in length from 1mm to >1m (brain
are shorter because there are a dense cluster of
them, no need for long distance transport)
o large stacks of RER and free ribosomes;
membrane protein synthesis; biosynthetic
centre of the neuron
• Axonal Transport
o Cellular railroad- MT (composed of tubulin) rails
running along length of axon that is used by
locomotives to transport materials/cargo
(vesicles, proteins, etc.) down and up axon
terminals to and from cell body.
find more resources at oneclass.com
find more resources at oneclass.com
2
o Anterograde transport (from cell body to synapse) → kinesin (+) walks along MT
o Retrograde transport (from Terminal to Body) → Dynein (-)
• Viruses can hijack railway and use it for itself
o Rabies virus
▪ 1. trick neuron to allow it entry by mimicking
structure of natural molecule to bind to receptors in
neuron
▪ 2. uses railway system to transport itself into cell
body thru retrograde transport
▪ 3. uses neurons own biosynthesis machinery to
make new viral protein to get released and start
process over again until virus is at CNS
Nucleus = cluster of cell bodies in CNS Collection of axons in CNS = Tract
Ganglion = cluster of cell bodies in PNS Collection of axons in PNS = Nerve
Nerve fiber = individual axon
Multipolar: Multiple dendrites
Bipolar: Only 2 dendrites which
converge and go to axon. 2 processes
Unipolar: Dendrites come together to
make 1 process at cell body and
immediately become an axon- not a
cell body. Cell body is just at the side.
Sensory: relay info to CNS.
Have receptive endings to
detect sensory info outside or
inside body.
Motor: efferent information.
Away from CNS.
Interneurons: in the CNS
surrounded by bony protective
structures
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Dendritic spine stick out of dendrites (when other neurons interact with dendrites, interaction occurs at the spine: axon: just 1 axon per neuron. They send signals out to other types of cells- single neuron can send out 1 signal (either sending or not sending signal). Nucleus = cluster of cell bodies in cns. Ganglion = cluster of cell bodies in pns. Bipolar: only 2 dendrites which converge and go to axon. Unipolar: dendrites come together to make 1 process at cell body and immediately become an axon- not a cell body. Have receptive endings to detect sensory info outside or inside body. Interneurons: in the cns surrounded by bony protective structures: neurons function: nerve impulse transmission, neurons generate and transmit nerve impulses. Ap occurs when neuron makes its own signal: axon hillock: junction btw cell body and axon. Consists of axon terminals and dendrites of next neuron + space of synaptic cleft.
