The Nervous System M5

Question 1

Explain the difference in the speed of conduction of an action potential along the length of a myelinated neuron and a non-myelinated neuron.

Answer 1

1. conduction is faster in myelinated neuron. 2. action potential can only occur where VG channels present. 3. myelinated neurons have longer sections with no VG channels present. 4. ion transfer can only take place at the nodes. 5. Saltatory conduction - action potential jumps from node to node

Question 2

Define Saltatory conduction

Answer 2

the propagation of an action potential along myelinated axons, from one node to another.

Question 3

How is the strength and intensity of a stimulus communicated to the brain.

Answer 3

The larger the intensity, the higher the frequency of action potentials.

Question 4

Define spatial summation

Answer 4

When impulses arrive from different neurons

Question 5

Define temporal summation

Answer 5

When impulses arrive at different times, and are added up.

Question 6

Describe the function of Pituitary gland

Answer 6

controlled by the hypothalamus, releases hormones to stimulate glands, the connection between the nervous and endocrine system

Question 7

Describe the function of the cerebellum

Answer 7

underneath the cerebrum, reasonable for control of movement and balance. Impulses are received from receptors in ears, muscles and joints.

Question 8

Describe the function of the medulla oblongata

Answer 8

found at the base of the brain, responsible for autonomic control of HR/BR

Question 9

Describe the function of the hypothalamus

Answer 9

found in the middle fo the brain. responsible for temp regulation, osmoregulation and produces a hormone that influences the pituitary gland

Question 10

Describe the function of the cerebrum

Answer 10

Divided into two hemispheres, conscious thought, intelligence, speech and memory.

Question 11

How do the structure of a motor neurone and sensory neuron?

Answer 11

a motor neuron has cells body at the end, the cell body is in the brain, dendrites connected to the cell body, longer axon, no dendron, the axon connects to effector

Question 12

How does the axon diameter affect the speed of conduction

Answer 12

Speed increased due to their being more voltage-gated sodium ion channels.

Question 13

Suggest an explanation for the fact that action potentials are not generated constantly wearing clothes.

Answer 13

sodium ion channels remain open so the resting potential is not re-established, ions are in the wrong place for correct ion movement.

Question 14

Outline the roles of synapses in the nervous system

Answer 14

1. cell signalling 2. transmission is in one direction. 3. convergence/divergence 4. low-level stimuli filtered out 5. prevents fatigue and over stimulation 5.permist memory and learning

Question 15

Suggest what impact temperature has on the speed of conduction

Answer 15

the increased amount of fo kinetic energy means ions can diffuse faster across the membrane which leads to faster depolarisation

Question 16

Explain the difference between a dendron and an axon.

Answer 16

Axon will carry the impulse away from the cell body whereas a dendron will carry the impulse towards the cell body.

Question 17

Types of the postsynaptic cell

Answer 17

Chlorogenic synapse is between two neurons, that can trigger an excitatory response or inhibitory, AP creates depolarization and enzyme is a synaptic cleft.
whereas a neuromuscular synapse ar between a motor neuron and a muscle, can only produce an excitatory response, AP triggers contraction, and the enzyme is in postsynaptic membrane.