Neurons and synaptic transmissions

Question 1

1-How many neurons are in the nervous system

2-What percentage of them are located in the brain

Answer 1

• 100 billion

- 80%

Question 2

What are the three types of neurons

Answer 2

• motor
• relay
• sensory

Question 3

What is the basic structure of a neuron

Answer 3

• cell body, including the nucleus which contains dendrites these carry nerve impulses to the cell body

Question 4

What does the axon do

Answer 4

• caries the impulse away from the cell body down the length of the neuron

Question 5

1-What does the myelin sheath do

2-What is the myelin sheath segmented by to speed up electrical transmissions

Answer 5

• protects the axon and speeds up electrical transmissions of the impulse
• gaps called nodes of ranvier

Question 6

The synapse includes a space between them as well as a __________ ________ ___ __________ _______ ____

Answer 6

• presynaptic terminal and postsynaptic receptor site

Question 7

signals within neurons are transmitted electrically, however signals between neurons are transmitted __________ __ ________ _____________

Answer 7

• chemically by synaptic transmission

Question 8

When the elctrical impulse reaches the end of the neuron it triggers the release of ________________ ____ ____ ____ ______ ________ ________

Answer 8

• neurotransmitter from tiny sacs called synaptic vesicles

Question 9

What are neurotransmitters

Answer 9

• chemicals that diffuse across the synapse to the next neuron in the chain

Question 10

What does each neurotransmitter have

Answer 10

• it’s own specific molecular structure that fits perfectly into a post-synaptic receptor site, similar to a lock and key

Question 11

What does the neurotransmitter serotonin cause

Answer 11

• inhibition in the receiving neuron resulting in the neuron becoming more electrically charged and less likely to fire

Question 12

What does adrenaline cause

Answer 12

• excitation of the postsynaptic neuron by increasing its positive charge and making it more likely to fire

Question 13

What is the space between two synapses called

Answer 13

• synaptic cleft

Question 14

How are signals within neurons transmitted

Answer 14

• electrically

Question 15

How are signals between neurons transmitted

Answer 15

• chemically by synaptic transmission

Question 16

When the electrical impulse reaches the end of the neuron ___________ ________ it triggers the release of ________________ from tiny sacs called ________ ________

Answer 16

• presynaptic terminal
• neurotransmitter
• synaptic vesicles

Question 17

What are neurotransmitters

Answer 17

• chemicals that diffuse across the synapse to the next neuron in the chain