Nervous Tissue/Neurotransmitters [B] Flashcards
Name the different parts of a nervous cell.
Nucleus, Dendrite, Cell body, Myelin Sheath, Node of Ranvier, Schwann Cell, Axon Terminals
What is the difference between myelinated and non myelinated nervous cells?
Non Myelinated: No myelin sheath, grey, slower impulse transmission, No nodes of Ranvier
Myelinated: Has myelin sheath, white, fast impulse transmission, Has nodes of Ranvier
Which 2 ions are involved in sending impulse signals across the cell?
Sodium (Na+) and Potassium (K+)
What is Saltatory Conduction?
It’s the name given to the movement of impulses by jumping from node to node
What is the state of a node at Resting Potential?
Negative ions inside, Positive outside
-70 Millivolts
What is the state of a node at Action Potential?
Positive ions inside, Negative outside
+40 Millivolts
What is an action potential?
Action potential is an electric signal transmitted across the axon when a nerve impulse is transmitted
Describe the process of a neurone sending an impulse.
Talk about the voltages, channels, ions, terms used
The stimulus exceeds the threshold so the neurone can fire.
The voltage sensitive sodium channels open up at the threshold and Sodium ions flood in (DEPOLARIZATION)
The neurone reaches 40 millivolts and the sodium channels close
Potassium channels open and Potassium leaves to decrease the voltage (REPOLARIZATION)
The voltage falls below -70Mv so there is a quick recovery time
Which ion plays a part in neurotransmission?
Calcium (Ca+)
Describe the process of neurotransmission.
Action potential arrives and calcium channels open up
The calcium ions make vesicles diffuse across the cleft and release neurotransmitters
Neurotransmitters bind to receptors to continue the signal
Some neurotransmitters open up Sodium channels and excess is broken down by enzymes.
What factors can affect impulse transmission?
Temperature
Diameter of the Axon
What does a Schwann cell contain inside?
Nucleus
