Unit 4 Reflex and Signalling

Question 1

The Reflex Arc is involved in

Answer 1

Withdrawal reflex

Question 2

The Reflex Arc is a circuit

Answer 2

That does not require the brain’s coordinating effort

Question 3

How are Interneurons also involved

Answer 3

Interneurons connected to the reflex circuits send signals to the brain, making you aware of the stimulus that caused the reflex

Question 4

What occurs when the reflex is a withdrawal one

Answer 4

You feel the pain shortly after the withdrawal

Question 5

With a withdrawal reflex and feeling the pain shortly after the withdrawal, the delay of feeling pain is a result of what?

Answer 5

The extra time required for impulses to travel from the neurons of the reflex to the brain

Question 6

State the steps of the Reflex Arc (Withdrawal Reflex) - 6 steps

Answer 6

1. Pain receptor in finger stimulates afferent neuron.
2. Afferent neuron transmits impulses to spinal cord
3. Interneurons in spinal cord integrate message/information
4. One efferent neuron stimulates the flexor muscle to contract
5. Other efferent neuron sends inhibitory signals that keeps the extensor muscle from contracting
6. Bicep muscle contracts, withdrawing hand from pain.

Question 7

Cytosol in neuron cell body does what

Answer 7

Provides a lot of resistance to the transmission of currents; thus, compared to electrical current, impulses travel much more slowly.

Question 8

During transmission, nerve impulses do not

Answer 8

Lose strength

Question 9

The site at which neuron-neuron connections occur is called

Answer 9

a synapse

Question 10

What connects in Neuron-Neuron Connections

Answer 10

Another neuron or effectors (muscles or glands)

Question 11

One side of synapse is

Answer 11

axon terminal or presynaptic cell

Question 12

Presynaptic Cell Meaning

Answer 12

Neuron that transmits signal

Question 13

Other side of synapse is

Answer 13

Dendrite or cell body of post-synaptic cell

Question 14

Postsynaptic Cell Meaning

Answer 14

neuron, or effector such as a muscle cell that receives the signal

Question 15

Two Synapse Types

Answer 15

Chemical
Electrical

Question 16

Chemical Synapse

Answer 16

Neurotransmitter, a chemical messenger is released by an axon terminal at a synapse.

Question 17

Chemical Synapse (how are neurons positioned)

Answer 17

plasma membranes of the presynaptic and postsynaptic cells are separated by a narrow gap called a synaptic cleft

Question 18

Electrical Synapse

Answer 18

plasma membranes of the presynaptic and postsynaptic cells are in direct contact, allowing the current to flow directly from one neuron to the next

Question 19

Electrical Synapse Step 1

Answer 19

When an electrical impulse arrives at the axon terminal, a gap junction allows ions to flow directly between the two cells, providing unbroken transmission of the electrical signal

Question 20

What does Electrical Synapse allow for?

Answer 20

Allow for very rapid transmission and synchronous activity in a group of neurons

Question 21

All animals cells have

Answer 21

Separation of positive and negative charges across plasma membrane.

Question 22

Positivity and Negativity in Cell

Answer 22

Positive outside; negative inside

Question 23

What is Positivity and Negativity difference in cell produce?

Answer 23

A voltage across the membrane called membrane potential.

Question 24

What is membrane potential caused by?

Answer 24

Uneven distribution of Na+ and K+ inside and outside the cell.