Lecture 4 Flashcards
Depolarization is the the result of
Na+ entering the cell
New Na+ channels open when
Graded potential crosses threshold potential
The inside of the cell becomes positively charged when
Na+ channels open and allow Na+ to enter the cell
Depolarization comes after
Graded potential
Voltage-gated Na+ channels are involved in
Depolarization
Repolarization is caused by the
Movement of K+ ions out of the cell
What happens during Repolarization?
Inside returns back to a net negative charge, near resting membrane potential
Voltage gated K+ channels are involved in
Repolarization
What happens during Hyperpolarization?
Cell drops briefly below the resting membrane potential
How are the concentrations of K+ during Hyperpolarization?
Equal at both sounds of the membrane
How is Hyperpolarization corrected?
By using active transport to move K+ back into the cell, returning the cell to -70mV
What should tell us about the function of the neuron?
Its structure
What are the three types of neurons?
- Sensory Neurons
- Brain Neurons
- Vertebrate Motor Neurons
Describe Sensory Neurons:
- One end has dendrites that allow sensory neurons to connect to different neurons
- Another has receptor associated with particular sense
Olfactory receptors are activated by
Chemicals in the air
Brain Neurons are known as
Interneurons
Describe Brain Neurons”
- Large number of dendrites on both ends to maximize connections with other neurons
- Short axon
- Send and receive messages over short distances between neurons
Describe Vertebrate Motor Neurons:
- Long axons for long distances
- Myelinated
- One end branches into neuromuscular junctions that connect neuron with target muscle cell
- Other end has lots of dendrites to connect muscles to the brain or spinal cord
Graded potentials form in the
Soma
The formation of graded potentials results in the
Formation of the action potential
Graded potentials are formed when
Na+ channels open
The Axon Hillock is responsible for
Integration
Graded potential travels through the soma towards the
Axon hillock
What happens in the Axon hillock?
The graded potential crosses threshold potential and causes action potential
Threshold potential is crossed and AP is triggered in axon hillock when
Enough Na+ enters the soma
The Axon Hillock is the region where
Graded potentials cause APs
