Nervous System

Question 1

What are the two types of nervous systems? And what do they include?

Answer 1

CNS - central nervous system: brain and spinal chord.

PNS - peripheral nervous system : somatic (voluntary actions) and autonomic (automatic actions).

Question 2

What are the two branches one somatic nervous system? What does SAME stand for and what does the A and E mean?

Answer 2

1. Sensory (sensations)
2. Motor (movement)
   Sensory
   Afferent - meaning, going to the brain.
   Motor
   Efferent - meaning, from the brain.

Question 3

What is the somatic nervous system responsible for?

Answer 3

For your voluntary actions.

And motor and sensory information.

Question 4

What is the autonomic nervous system responsible for?

Answer 4

Involuntary actions of internal organs and glands.

Eg, blinking, breathing, digestion and heart rate.

Question 5

What are the two branches coming off the autonomic nervous system? What do they do?

Answer 5

1. Sympathetic:
   - activated in times of stress.
   - responsible for your fight, flight or freeze mode.
   - increases heart rate.
   - increases breathing.
   - its protective, and we don’t control it.
   - pupils dilate.
2. Parasympathetic:
   - brings everything back down like a parachute.
   - returning to a state of calm known as homeostasis.
   Eg, digestion resting.

Question 6

What does a sensory neuron do?
What does a motor neuron do?
What does an inter neuron do?

Answer 6

SN - conveys the sensation to the brain (CNS)
MN - sends messages away from the CNS to the specific muscle, gland or organ.
IN - relays signals between the sensory neurons (the middle man).

Question 7

What are the components of a neuron?

Answer 7

Dendrites, soma, axon, terminal buttons, myelin sheath, glial cells, nucleus.

Question 8

Function of dendrites:

Answer 8

Branch like segments of a neuron, which receive signals from other neurons or sensory receptors via the synapse and deliver these to the soma.

Question 9

Function of the soma:

Answer 9

The cell body, and the largest part of the neuron, that controls the metabolism and maintenance of the cell.

Question 10

Function of the axon:

Answer 10

The part of the neuron along which the electrochemical nerve - impulse is transmitted.

Question 11

Myelin sheath function:

Answer 11

Myelin sheath is a white, fatty, waxy substance that coats some axons and insulates them, protecting them from electrical interference from other neurons. This increases the efficiency of transmission of nerve impulses.

Question 12

Terminal buttons function:

Answer 12

The end of each axon has terminal buttons that secrete a chemical called a neurotransmitter whenever information is sent down the axon in the form of electrical impulses.

Question 13

Glial cells function:

Answer 13

Cells that play an important role in supporting neurons by surrounding and holding them in place, supplying nourishment and oxygen, removing dead neurons and insulating neurons to increase the speed of nerve impulse transmission.

Question 14

Nucleus function:

Answer 14

It contains the majority of the cell’s genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.

Question 15

What is a neural pathway?

Answer 15

The pathways that nerve impulses take along the neurons, and allow on part of the nervous system to communicate with another.
A neural path way can carry messages from the body to the brain (afferent pathways), from the brain to body (efferent pathways) or within the brain itself.

Question 16

What is a synapse?

Answer 16

A synapse is a junction between two neurons. The presynaptic neuron releases molecules of neurotransmitters from vesicles (sacs full of neurotransmitters), which then fit into receptor sites on the postsynaptic neuron. The charge builds up until a signal, the ‘action potential’ is sent down the postsynaptic axon.

Question 17

What is a neurotransmitter?

Answer 17

A chemical that help the communication across nerve synapses.

Question 18

What is the difference between a reflex action and a reaction?

Answer 18

Reflexes are involuntary actions that do not involve the brain when responding to a stimulus. They occur almost instantly when triggered by a certain external stimulus.

Eg, when we feel the cold, out body’s REFLEX produces goosebumps and causes shivering to try and induce warmth. HOWEVER, our conscious REACTION - with the same goal (to stay warm) - is to rub the skin on our arms or perhaps jump up and down on the spot.