Chapter 1: The Nervous System

Question 1

_______________ is the master controlling and communicating system of the body.

Answer 1

The nervous system

Question 2

The Nervous System has three overlapping functions:

Answer 2

Sensory Input

Integration

Motor Output

Question 3

The nervous system processes and interprets the sensory input and makes decisions about what should be done at each moment. This process is called ___________ .

Answer 3

Integration

Question 4

The nervous system uses millions of sensory receptors to monitor changes occurring both inside and outside the body. These changes are called ________ and the gathered information is called ___________.

Answer 4

Stimuli

Sensory input

Question 5

The nervous system causes a response by activating effector organs (muscles and glands). This response is called:

Answer 5

Motor output.

Question 6

The Nervous System consists of two principal divisions.

Answer 6

The Central Nervous System (CNS)

The Peripheral Nervous System (PNS)

Question 7

Consists of the brain and spinal cord which occupies the dorsal body cavity. Known as the integrating and command center of the Nervous System.

Answer 7

The Central Nervous System (CNS)

Question 8

The part of the Nervous System outside the CNS and consists mainly of the nerves that extend from the brain and spinal cord.

Answer 8

The Peripheral Nervous System (PNS)

Question 9

What is the function of the Central Nervous System (CNS)?

Answer 9

It interprets incoming sensory information and dictates responses based on past experience, reflexes and current conditions.

Question 10

___________ carry impulses to and from the spinal cord and cranial nerves carry impulses to and from the brain. These peripheral nerve serve as communication lines that link all parts to the CNS.

Answer 10

Spinal nerves

Question 11

The Peripheral Nervous System has two subdivisions:

Answer 11

The Sensory (afferent) division

The Motor (efferent) division

Question 12

Keeps the CNS constantly informed of events going on inside the body. It consists of nerve fibres that transmit impulses to the CNS from sensory receptors, located throughout the body.

Answer 12

The Sensory (afferent) division

Question 13

Two parts of the sensory (afferent) division:

Answer 13

Somatic Afferents

Visceral Afferents

Question 14

Sensory fibres that convey impulses from the skin, skeletal muscles and joints.

Answer 14

Somatic Afferents

Question 15

Sensory fibres that convey impulses from the visceral organs.

Answer 15

Visceral Afferents

Question 16

Consists of nerve fibres that transmit impulses from the CNS to effector organs. These impulses activate muscles to contract and glands to secrete (these fibres bring about a motor response).

Answer 16

The Motor (efferent) division

Question 17

Two parts of the Motor (efferent) division :

Answer 17

Somatic Nervous System

Autonomic Nervous System

Question 18

Made up of somatic motor nerve fibres that conduct impulses from the CNS to skeletal muscles.

Answer 18

Somatic Nervous System

Question 19

Made up of visceral motor nerve fibres that conduct impulses from the CNS to smooth muscles, cardiac muscles and glandular epithelial tissue.

Answer 19

Autonomic Nervous System

Question 20

The Autonomic Nervous System itself has two divisions called:

Answer 20

Sympathetic Nervous System

Parasympathetic Nervous System

Question 21

True or False:

Parasympathetic Nervous System is also known as “ fight and flight” system.

Answer 21

False:

Sympathetic Nervous System (fight and flight) Parasympathetic Nervous System (rest and digest)

Question 22

There are no intervening synapses; nerve conduction is from the spinal cord or brainstem, directly to somatic effectors.

Answer 22

Somatic Nervous System

Question 23

Its activity is evident when we are excited or find ourselves in an emergency or threatening situations.

Answer 23

Sympathetic Division (Thoracolumbar)

Question 24

Chiefly concerned with keeping our body energy as low as possible, even as it directs vital activities such as digestion and elimination. It is most active in non-stressful situations.

Answer 24

Parasympathetic Division (Craniosacral division)

Question 25

Cells of the Nervous System:

Answer 25

Neurons Glia cells (neuroglia)

Question 26

\_\_\_\_\_\_\_\_ are nerve cells. They are the structural unit of the nervous system.

Answer 26

Neurons

Question 27

Function of neurons:

Answer 27

They conduct messages in the form of impulses from one part of the body to another.

Question 28

What are the characteristics of neurons?

Answer 28

Extreme longevity They can not divide (usually) Exceptionally high metabolic rate

Question 29

Characteristics of neurons. True or False a) Extreme longevity - Nerve cells can live over a hundred years (or, as long as the person lives). b) They can not divide (usually) - They can not be replaced if destroyed. c) Exceptionally high metabolic rate - They constantly need oxygen and glucose; without it, they will die in a matter of 3 to 5 minutes.

Answer 29

True

Question 30

Each neuron consists of three parts:

Answer 30

Dendrites Cell body Axon

Question 31

Also called the soma. It contains a nucleus and most other organelles,except for centrioles.

Answer 31

Cell body

Question 32

They are receptor, input regions that conduct impulses towards the cell body. All the organelles present in the cell body, are also present in the dendrites.

Answer 32

Dendrites

Question 33

Conducts impulses away from the cell body. It contains the same organelles that are found in the cell body (with exception of the nucleus).

Answer 33

Axon

Question 34

True or false: Each neuron has one axon.Although each neuron has only one axon, the axon may branch to form axon collaterals . These axon collaterals extend from the axon, at right angles. The distal end of the axon branches into axonal terminals, synaptic knobs.

Answer 34

True

Question 35

The axon arises from a cone shaped region of the cell body called \_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 35

The axon hillock

Question 36

\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - Supporting cells that do not specialize in transmitting impulses. Instead, they help protect and hold the functioning neurons together. Outnumber neurons in the CNS 9 to 1 and make up about half the mass of the brain.

Answer 36

Glia cells (neuroglia)

Question 37

Types of Glia (supporting) cells in the CNS:

Answer 37

Astrocytes Microglia Oligodendrocyte Ependymal

Question 38

Star-shaped and most abundant glia cells. They anchor small blood vessels (capillaries) to neurons and help form the blood-brain barrier.

Answer 38

Astrocytes

Question 39

\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is a selective barrier that separates the blood tissue and the nervous tissue, against harmful chemicals that might be in the blood.

Answer 39

The blood - brain barrier

Question 40

What are the functions of blood - brain barrier ?

Answer 40

\* Protects the brain from the possible leakage of harmful chemicals, from the blood into the brain. \* Keeps some helpful drugs, such as antibiotics, from gaining access to the brain, in order to deal with such harmful diseases as bacterial meningitis.

Question 41

They are a type of macrophage and are usually stationary and monitor the health of nearby neurons. Extremely important because cells of the immune system are denied access to the CNS.

Answer 41

Microglia

Question 42

Response of microglia when neurons are injured.

Answer 42

When microglia sense that neurons are injured, or in trouble, they enlarge and move about and act as microbe-eating scavengers.

Question 43

\_\_\_\_\_\_\_\_\_\_\_\_ - Help hold nerve fibres together and form myelin sheaths, on axons in the CNS.

Answer 43

Oligodendrocyte

Question 44

\_\_\_\_\_\_\_\_\_\_\_\_\_ - line the central cavities of the brain and spinal cord. They form a permeable barrier between the cerebrospinal fluid that fills those cavities and the tissue fluid bathing the cells of the CNS. Their cilia help to circulate the CSF.

Answer 44

Ependymal

Question 45

Supporting cells (Glia cells) of the PNS:

Answer 45

Schwann cells Satellite cells

Question 46

\_\_\_\_\_\_\_\_\_\_ - These cells wrap themselves around axons of some nerve fibres found in the PNS.

Answer 46

Schwann cells

Question 47

The outer cell membrane of the Schwann cell is called the ________ and can play an important role in the regeneration of cut and injured axons.

Answer 47

Neurilemma

Question 48

Schwann cells along the axon do not touch and leave gaps called \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 48

Nodes of Ranvier

Question 49

\_\_\_\_\_\_\_\_\_\_\_ - Very similar to Schwann cells except for location. These cells surround neuron cell bodies within ganglia and play a role in controlling the chemical environment surrounding the neuron.

Answer 49

Satellite cells

Question 50

Classification of Neurons:

Answer 50

Structural Classification Functional classification

Question 51

Three major types of structural classification of neurons:

Answer 51

a. Multipolar b. Bipolar c. Unipolar

Question 52

Neurons can be grouped structurally according to the number of processes, extending from their cell body.

Answer 52

Structural Classification

Question 53

Group neurons according to the direction in which the nerve impulse travels, in relation to the CNS

Answer 53

Functional classification

Question 54

Type of structural classification of neurons that: a) Have three or more processes (all dendrites except for a single axon) b) Most common type in humans c) Major type in CNS d) Neurons have numerous branching dendrites and one axon. e) Some neurons in this class do not have an axon, only dendrites.

Answer 54

Multipolar

Question 55

Type of structural classification of neurons that: a) Have two processes (one is a dendrite, the other is an axon) b) Rare in adult body c) Found only in special sense organs like the retina of the eye

Answer 55

Bipolar

Question 56

Type of structural classification of neurons that: a. Also called ___________ because they originate as bipolar and change during embryonic development. b. Here a single process emerges from the cell body. The process divides into proximal and distal fibres. c. The more distal process is called \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. d. The process entering the CNS is called \_\_\_\_\_\_\_\_\_\_\_\_\_. e. The cell bodies are found in the ganglia in the PNS

Answer 56

Unipolar pseudo-unipolar peripheral process central process

Question 57

Types of functional classification of neurons:

Answer 57

Sensory neurons Motor neurons nterneurons (association neurons)

Question 58

Which statement is false regarding Sensory neurons? a. They transmit impulses from sensory receptors in the skin and internal organs towards the CNS. b. Most sensory neurons are multipolar and their cell bodies are located in dorsal root ganglia inside the CNS. c. Functionally, only the most distal parts of these unipolar neurons act as impulse receptor sites and the peripheral process formed by the joining of the dendritic branches, are often very long.

Answer 58

B. ## Footnote Correct: Most sensory neurons are unipolar and their cell bodies are located in dorsal root ganglia outside the CNS

Question 59

Type of functional classification of neurons: These neurons lie between motor and sensory neurons.Typically multipolar and are only found in the CNS. Make up over 99% of the neurons in the body.

Answer 59

Interneurons (association neurons)

Question 60

\_\_\_\_\_\_\_\_\_\_ carry impulses away from the CNS to effector organs, they are multipolar. Most cell bodies are located in the CNS (except for the ANS). They form junctions with their effector organs called the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 60

Motor neurons neuromuscular junctions

Question 61

Type of functional classification of neurons: These neurons lie between motor and sensory neurons.Typically multipolar and are only found in the CNS. Make up over 99% of the neurons in the body.

Answer 61

Interneurons (association neurons)

Question 62

\_\_\_\_\_\_\_\_\_\_ carry impulses away from the CNS to effector organs, they are multipolar. Most cell bodies are located in the CNS (except for the ANS). They form junctions with their effector organs called the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 62

Motor neurons neuromuscular junctions