celule din creier 1 Flashcards
What did Luigi Galvani do?
He demonstrated that nerves conduct electricity
Galvani connected a nerve taken from a frog leg to a metallic wire
He pointed the metallic wire at the sky during a thunderstorm
This resulted in a muscular contraction of the frogs leg
What did Ramon y Cajal do?
He was able to identify different part of the neurones (the axon and the synapse)
This disputed the previous idea that communications flows through an interrupted net
What did Otto Loewi do?
Otto Loewi demonstrated that neurones communicate with each other by means of chemical transmission.
He took the still-beating hearts of 2 frogs, one with a vagus nerve and one without
He placed them into separate buckets
He stimulated the heart with a vagus and the heart beating started to slow down. Then he collected the fluid of the stimulated heart and poured the liquid into the 2nd bucket where the second heart started to slow down too.
This demonstrates that after the stimulation of the first heart, some substance was diffused in the liquid of the first bucket, and then when the liquid was poured in the 2nd bucket this substance stimulated the 2nd heart.
He named the chemical substance vagusstoff
What are the 2 main types of brain cells?
Neurons - receive information and transmit it to other cells
Glia cells - provide chemical support to neurones. They do not transmit information
What are the 3 main types of glia?
- Astrocytes
- Oligodendrocytes
- Microglia
What are the functions of astrocytes?
Hold neurones in place
Provide nourishment to neurones
Form the blood brain barrier
Provide support in the synapse
What are the functions of oligodendrocytes?
Provide myelin sheath to neuronal axons
What are the functions of microglia?
Smallest of the glia cells
Clean up dead tissue
Support the immune system
Who introduced the terms neurone and synapse?
Charles Sherrington
What are neurones?
Specialised cells that transmit information to other cells and muscle and gland cells
What are dendrites?
They receive messages from presynaptic terminals of another neurone.
Transfer messages to the soma of the neurone.
Some contain dendritic spines which are small outgrowths that increase dendrites’ surface area allowing a greater number of connections.
What is an axon?
Long tube that carries information (action potential) from the cell body down to the terminal buttons
Covered in myelin which speeds information
What is the presynaptic terminal?
terminal buttons
Contains special chemicals called neurotransmitters which are released into the synaptic cleft.
The receptor area may be either on a dendrite or the soma of the next neurone.
What is action potential?
An electrical current that travels along the axon.
As it travels down the axon, there is a change in polarity across the membrane.
The Na+ and K+ ion channels open and close as the membrane reaches the threshold potential in response to a signal from another neurone.
What is membrane potential?
The difference in the electrical charge between inside and outside of the neurone’s cell.
