The Nervous System

Question 1

Function of the Central Nervous System

Answer 1

A rapid communication system which acts as the main coordinator of body functions.

1. Regulates the internal environment
2. Regulates and coordinates all other body systems (including higher functions ie. thinking, reasoning, emotions)

Question 2

How does the nervous system communicate?

Answer 2

Through the use of electrical and chemical signals carried out by neurons.

Question 3

Basic structures of the Neuron

Answer 3

1. Dendrites
2. Cell body
3. Axon
4. Axon terminals

Question 4

How is information sent through the Nervous System?

Answer 4

1. Information comes in through the sensory receptors (eys, skin, fingers, etc).
2. It is transmitted as sensory input to the CNS (brain and spina cord).
3. The CNS integrates this information.
4. The CNS sends motor output out to the body.
5. This output triggers the effector, causing muscles to move according to the signal sent.

Question 5

Parts of the Central Nervous System

(CNS)

Answer 5

The CNS is made up of the brain and the spinal cord.

Thes organs contain neural tissue, blood vessels and connective tissues.

Question 6

Parts of the Peripheral Nervous System

Answer 6

PNS is comprised of the cranial and spinal nerves and all nerves outside the CNS.

Question 7

Function of the CNS

Answer 7

Integrates, processes and coordinates sensory data and motor commands.

Question 8

Function of the PNS

Answer 8

Sends sensory data from the sense organs to the CNS and motor commands from the CNS to the peripheral tissues and organs.

Question 9

Two Divisions of the Peripheral Nervous System

Answer 9

1. Afferent Division - sensorty data from the sense organz to the CNS
2. Efferent Division - Motor commands from the CNS to the effector organs

Question 10

Two Parts that Make up the Efferent Division of the PNS

Answer 10

1. Somatic Nervous System - controls muscle contractions
2. Autonomic Nervous System - Controls reflexes, organs and tissues not under voluntary control.

Question 11

What is the Efferent Division of the Nervous System?

Answer 11

Part of the Peripheral Nervous Sytem.

Controls motor commands from the CNS to the effector organs.

Question 12

What is the Afferent Division?

Answer 12

Part of the PNS.

Nerves pass sensory information from the sense organs to the CNS.

Question 13

Somatic Nervous System

Answer 13

Controls skeletal muscle contractions. Conscious ability to move your muscles.

Question 14

Autonomic Nervous System

Answer 14

Controlled at subconscious level.

This includes reflex actions, all organs and tissues not under voluntary control (including smooth muscle of the walls of airways and blood vessels).

Separated into two systems:

1. Sympathetic
2. Parasympathetic

Question 15

Two Parts of the Autonomic Nervous system

Answer 15

1. Sympathetic - mobilizes the body during stressful situations (flight or flight)
2. Parasympatheic - responsible for aquisition and storage of resources, predominates when the body is at rest.

Question 16

Sympathetic Autonomic Nervous System

Answer 16

Responsible for mobilizing the body to deal with stressful situations (fight or flight) and predominates during times of stress.

Question 17

Parasympathetic Autonomic Nervous System

Answer 17

Responsible for the acquisition and storage of resources and predominates when the body is at rest.

Question 18

Four Parts of the Brain

Answer 18

1. Cerebrum
2. Diencephalon
3. Brain Stem
4. Cerebellum

Question 19

Cerebrum

Answer 19

Divided into two cerebral hemispheres.

Each hemisphere controls the contralateral side of the body.

Question 20

What is the Diencephalon composed of?

Answer 20

1. Thalamus
2. Hypothalamus

Question 21

Function of the Thalamus

Answer 21

Comprised of several clusters of neurons.

Is the main relay center for sensory information arriving in the brain.

Screens out unimportant information beforing routing the signals to the appropriate area of the cerebral cortex.

Plays an important role in controling voluntary movement.

Question 22

Function of the Hypothalamus

Answer 22

Lies beneath the thalamus.

Is connected to the pituitary gland.

Controls the release of hormones from this gland.

Made up of a large number of (neuron) nuclei.

Repsonsible for regulating sleep and wake cycles, apetite, thirst, water balance, sexual behavior, and body temperature.

Overall control of the Autonomic Nervous System.

Question 23

Three Structures of the Brain Stem

Answer 23

1. Medulla Oblongata
2. Pons
3. Midbrain

Question 24

What type of tissue is found in the brain stem?

Answer 24

The tissue in the brain stem is different than that of the rest of the nervous system.

It is composed mainly of white matter with small clusters (nuclei) of gray matter scattered throughout.

Question 25

Reticular formation

Answer 25

Nuclei of gray matter scattered throughout the brain stem.

Question 26

Function of the Brain Stem

Answer 26

A two way conduction system. Sensorty pathways conduct signals up from the spinal cord to the rest of the brain, and motor pathways conduct signas down from the brain to the spinal cord. Some nerve fibers pass through, but most synapse in the brain stem.

Question 27

Reticular Activating System | (RAS)

Answer 27

Neurons of the reticular formation (gray matter nuclei scattered throughout the brain stem) receive sensory imput and communicate nervous energy to the cerebral cortex, cardiovascular and respiratory systems.

Question 28

Stimulation of RAS Nerves...

Answer 28

Arouses and maintains consciousness, maintains alertness and attention,

Question 29

Lack of Stimulation of RAS nerves....

Answer 29

(ie darkness or a quiet room) Induces drowsiness.

Question 30

How to general anesthetics function?

Answer 30

Supress the RAS nerves.

Question 31

How is clinical manifestation of brain death determined?

Answer 31

Lack of electrical activity in the brain stem.

Question 32

Vital Centers associated with Autonomic Reflexes found in the medulla include:

Answer 32

1. **The Cardiovascular Center** - Controls the rate and force of contraction of the heart. 2. **The Respiratory Center** - controls the rate and depth of breathing 3. **The Reflex Centers** - irriation of airways or stomach activate the reflex centers in the medulla to induce coughing, sneezing or vomitting ot remove the irritant. Swallowing and blinking reflexes are also associated with the medulla.

Question 33

Cardiovascular Center

Answer 33

Found within the medulla. Controls the rate and force of the contraction of the heart. Also contains the vasomotor center which controls the diamater of blood vessels (especially arterioles and arteries).

Question 34

Vasomotor Center

Answer 34

Located within the Cardiovascular center of the medulla (in the brain stem). Controls the diamter of blood vessels (especially arterioles and arteries).

Question 35

Respiratory Center

Answer 35

Located in the medulla within the brain stem. Controls the rate and depth of breathing. Functions in close association with similar nuclei in the pons.

Question 36

Reflex Centers

Answer 36

Located in the medulla of the brain stem. Irritation in the airways or stomach activate this reflex center which induces coughing, sneezing or vomiting to remove the irritant. Swallowing and blinking reflexes are also associated with the medulla.