Class Notes (811,225)
Canada (494,571)
Physiology (634)
PSL201Y1 (124)
Lecture 2

Physiology Lecture 2.docx

8 Pages
Unlock Document

University of Toronto St. George
Michelle French

Physiology Lecture 2 Sept 17, 2013 The notes only make sense when read alongside the slides. If something's on the slides, it probably isn't in my notes. esp = especially 90-95% of test questions are from lectures. rest is from text. Nervous System at the seat of thinking, feeling, consciousness Central Nervous System (CNS) consists of brain and spinal cord Peripheral Nervous System (PNS) further divided into afferent (info coming in, i.e. visuals) and efferent info (brain computes info, i.e.: I see a black box) each neuron can connect up to 10 000 other neurons PNS lies outside CNS PNS subdivided into autonomic and somatic efferent system carries info out to systems, i.e. to cardiac system skeletal muscle control regulated by somatic: voluntary control Cells in CNS i.e. neurons neurons are excitable - can generate a signal and carry that signal COMPONENTS OF A NEURON soma: cell body dendrite: similar to a net that catches/receives incoming information axon: piece of wire that carries/conducts the signal (action potential) axon hilla: where the axon originates axon terminal: where the neurotransmitters are released presynaptic neuron: before the synapse. the one who sends the signal. post synaptic neuron: after the signal. the one who receives the signal. GLIAL CELLS supporting cells. glued to the system. 5 types of glial cells: 1. astrocytes - mop up transmitters. provide energy. provide guidance for developing neurons (in babies for example). called astrocytes because look like stars under a microscope. 2. ependymal - line cavity of the ventricles in brain 3. microglia - involved in phagocytosis. protection of nervous system. 4. oligodendrocytes - used for myelienation (forming myelin) found in CNS myelin is insulation made of fat piece of biological tissue is not a good conductor signal that you put in, will lose signal by the time it reaches its destination. signal will be blurry at destination. but copper wires are good at conducting signals form myelin/insulation. form several myelin sheaths. myelienate specific sections of the axon. wraps a bunch of axons individually 5. schwann cells - found in PNS. form around one section of an axon myelin sheath helps transmit the signal more efficiently and faithfully shwann cell wraps around cell to form the myelin sheath NODE OF RANVIER unlike coaxial cable, does not myelienate entire axon. areas that are not myelienated. these exposed areas are called node of ranvier. in our body, the conduction velocity of the fastest myelienated axon is 80m/sec vs unmyelinated axon could be as slow as 2m/s not all neurons are myelienated. cats have more myelienation and therefore faster velocity myelin forming cells coaxial cable has insulation that helps better transmission than just a copper wire. signal remains more faithful to where it originated. CASE STUDY what would happen if we lost myelienation? multiple sclerosis -visual disturbance -trouble with coordination and balance -sensations of numbness -memory problems one of the drugs used in alleviating sxs for MS are the ones that block potassium channels ION CHANNELS leak channels: -always open -pores found in membrane through which ions can cross -need them to generate signals -found throughout plasma membrane, throughout neuron i.e.: potassium can always cross through a potassium leak channel
More Less

Related notes for PSL201Y1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.