5.1.3-neuronal communication

Question 1

what are 2 functions of sensory receptors
5.1.3(a)

Answer 1

1. only respond to a specific stimulus
2. Acts as transducers

Question 2

what are transducers
5.1.3(a)

Answer 2

converts one form of energy into another
eg-stimulus (kinetic, mechanical or chemical)
into action potential-electrical

Question 3

describe the pacinian corpuscle
5.1.3(a)

Answer 3

-lamellae
-sensory neuron

Question 4

why is the pacinian corpuscle a transducer
5.1.3(a)

Answer 4

converts mechanical into electrical energy

Question 5

how is an action potential generated in a pacinian corpuscle
5.1.3(a)

Answer 5

1. Mechanical pressure causes pressure sensitive Na+ channels to open
2. Na+ enters neuron and the build up of positive charge inside causes depolarisation
3. Multiple generator potentials build up when the threshold value is reached this causes an action potential which is sent to the CNS

Question 6

what does the size of the stimulus determine
5.1.3(a)

Answer 6

-size of the receptor potential
-number of action potentials triggered

Question 7

what is the role of sensory neurons
5.1.3(b)

Answer 7

carry action potentials from the sensory receptor to CNS

Question 8

what is the role of motor neurons
5.1.3(b)

Answer 8

carry action potentials from CNS to effector cells eg-muscles and glands

Question 9

what is the role of relay neurons
5.1.3(b)

Answer 9

connect sensory and motor neurons

Question 10

what is the mylein sheath made up of
5.1.3(b)

Answer 10

schwann cells which secrete mylein

Question 11

what are gaps between the axon called
5.1.3(b)

Answer 11

Nodes of ranvier-action potentials jump from one node to the next this is known as saltatory conduction-this increases transmission speed.

Question 12

what do all neurons have
5.1.3(b)

Answer 12

-Plasma membrane with many gated ion channels
-have a cell body with many mitochondria (for ATP production) ribosomes (for synthesis of channel protein and neurotransmitter proteins) and the cell nucleus

Question 13

what is a resting potential
5.1.3(c)

Answer 13

-when its not transmitting an action potential
-actively transporting ions across the membrane

Question 14

what is resting potential
5.1.3(c)

Answer 14

voltage across a neuron membrane when not stimulated

Question 15

what is a refractory period
5.1.3(c)

Answer 15

-during hyperpolarisation this section of the axon membrane is unresponsive
-ensures action potential are discrete/ can only travel in one direction.