Chapter 4 Midterm 1 Flashcards
Why do we use 60 Hz in lights?
Is the deadliest frequency, made so that people would be cautious around it
Who was the first to propose a mechanistic theory of behaviour?
Descartes
Two types of experiments were first done to deduce the relationship between electricity and animal tissue, what were they?
Electrical stimulation- current left a stimulator and entered tissue, stimulated it and thenflowed back to stimulator through reference electrode.
- stimulating electrode delivered current ranging from 2 to 10 milliamps, can produce a response without damaging tissue.
Electrical recording- Brain makes current and this is measured by an EEG- diff in voltage between recording electrode and reference electrode was recorded.
How are seizures treated?
They are diagnosed by putting you to sleep and inducing a seizure and then measuring electrical currents using eeg.
What are the most common seizures?
Febral seizures, these seizures are induced by infections which turns into a fever, if kids pant they change alkalinity of blood this combined with heat causes seizures
What did Galvani do?
Applied an electrical current to a dissected nerve and induced a twitch in the muscle
What did Fritsch and Hitzig do?
Found that electrical stimulation of the neocortex causes movement (arms and legs)
What did Bartholow do?
First report of human brain stimulation
What did Caton do?
First to attempt to measure electrical currents of the brain and electrodes on the skull
What did Berger do?
Developed the electroencephalogram (EEG), was a graph of electrical activity from the brain and represents the average graded potential of many neurons.
What did von HelmHoltz discover?
That the flow of information in the nervous system is too slow to a flow of electricity.
Nerve conduction is 30-40 meters/second
Electricity is 3x10^8 meters/second- a million times faster
Do the ions travel along the axon?
No a wave of charge travels along the axon.
How does the wave travel through the axon?
Sodium rushes in and potassium rushes out, as the ions go up and down the wave from the ions travel across the axon
What is an oscilloscope?
is a computer than can display the change in voltage over time.
What animal has the largest axon? Why?
in north atlantic squid, this helps the squid live in very cold waters as axon can stimulate muscles to propell themsleves through water, otherwise squid couldn’t live there as ions wouldn’t be able to move in that cold of water.
What is a concentration gradient?
Is a term that describes the relative differences in concentration of a substance between two spatial locations.
Why can’t chloride ions disperse evenly in a semipermeable membrane?
Because they have attraction to sodium ions, so they aggregate towards the membrane surface.
What is the membranes resting potential?
-70 mV
What did Hodgkin and Huxley do?
Measured electric potential of axon of north atlantic squid
What are the concentrations of anions and potassium inside the axon, relative to outside the axon
Have higher concentration inside
What are the concentrations of chloride and sodium inside the axon, relative to outside the axon
have higher concentration outside