Basic structure and action potential Flashcards
What does the CNS consist of
brain and spinal cord
What are the two main types of cells
- NEURONS (recieve and transmit info in electrochemical form)
- GLIAL CELLS (supports neurons in function e.g nutrition/cleaning)
What are the main components of a neuron
- CELL BODY
- DENDRITES (brings info into neuron)
- AXON (mylen sheath, interruptions in the sheath is called nodes of ranvier)
- AXON TERMINAL
Describe the Multipolor neuron, Bipolor neuron and Monopolar neuron
Multipolor neuron - many dendrites and a single neuron
Bipolor neuron - single dendrite at one end and single axon at other end
Monopolor neuron - single branch going in two directions with a soma in the middle
What does PNS consits of
- Sensory neurons (afferent, skin to CNS)
- Motor neurons (efferent, CNS to muscle)
- interneurons (connection point between sensory and motor neurons)
Outline the glial cell: Astrocytes
- largest glial cell
- helps regulate blood flow in the brain
Outline the glial cell: Microglia
- smallest glial cell
- removes dead cells (part of immune system)
Outline the glial cells: Oligodendrocytes/schwann cells
produces myelin which dramatically increases speed which action potential travels down axon
What is a nerve impulse
An electrical message transmitted down axon
What is the membrane potential
The difference in electrical charge between the inside and outside of the cell (-70 mV) (polarization)
What is the resting potential
state of neuron prior to sending off a nerve impulse
What kind of gradient does a neuron membrane potential maintain
electrical
The membrane is selectively permeable (some chemicals pass more freely than others), what chemicals cant pass freely
- sodium (Na+)/Chloride (CL-) = higher concentration outside of the cell
- Potassium (K+) = higher concentration inside the cell.
Salty banana
What two gradients drive Na+ in and pushes K+ out
- electrical gradient
- concentration gradient
Describe hyperpolarization and depolarization in the action potential
hyperpolarization - membrane potential becomes more negative than when at resting potential
depolarization - membrane potential becomes more positive than when at resting potential
When does a nerve impulse (action potential) occur
when the threshold of excitation is met, threshold varies (-65mv)
What is the name for the state before membrane returns to resting potential
temporary hyperpolarisation
The sodium potassium pump restores the original distribution of ions, what is the quantity of Na+ and K+
3Na+ ions exported out for every 2k+ ions brough into the cell
What are absolute and relative refractory periods
Absolute = first part of the period, membrane cant produce an AP
Relative = second part of the period, stronger than usual stimulus to trigger another AP
What quantity is resting potential
- 70 mv
what is all or none law
when amplitude and velocity of action potential is the same for a given neuron
What is the rate law
strength of a stimulus is represented by the firing rate of an axon
how do signals travel through axon
jumps from node to node (saltatory conduction)
What is the sights at which the cell synthasizes new protein molecules called
ribosomes
what is the resting potential of a neuron
the net negative charge on the inside of the neuron
what function cant glia cells do
transmit information
