Chapter 2a And 2b (2b Is Bookmarked )

Question 1

What does the nervous system enable

Answer 1

Brains and body to exchange neural messages and communicate with one another

Question 2

Central nervous system

Answer 2

The central nervous system comprises the brain and spinal cord and is therefore ‘central’ to the
body. It is from this centre that all bodily activity is coordinated and integrated.

a major division of
the nervous system comprising the brain
and spinal cord, which receives neural messages from and transmits
neural messages to the peripheral nervous system

Question 3

Two main divisions of the nervous system

Answer 3

Central
Peripheral

Question 4

Brain and spinal cord

Answer 4

Brain a complex organ contained within the skull that coordinates mental processes and behaviour, and regulates bodily activity, Carrie’s motor info from cns to muscles
Spinal cord a cable of nerve tissue that extends from the brain, connecting it to the peripheral nervous system, Carries sensory info from sensory receptors to the cns (transmits messages to and from the brain)

Question 5

Peripheral nervous system

Answer 5

The peripheral nervous system comprises all the neurons outside of the brain and spinal cord. These neurons are in the periphery of your body, connecting the central nervous system with your external world.

a major division of
the nervous system comprising every neuron in the body outside the central nervous system

Question 6

Divisions of the peripheral nervous system

Answer 6

Somatic
Autonomic

Question 7

Somatic nervous system

Answer 7

The somatic nervous system is a division of the peripheral nervous system that transmits
neural messages related to voluntary motor movement. The somatic nervous system comprises:
• sensory neural pathways, which are made up of sensory neurons.
• motor neural pathways, which are made up of motor neurons.
Sensory neural messages travel from sensory receptors, which are nerve endings that detect sensations, to the central nervous system via afferent neural pathways in the somatic nervous system. Motor neural messages travel from the central nervous system to skeletal muscles, which are muscles connected to the skeleton that carry out voluntary motor movements,
via efferent neural pathways in the somatic nervous system. In this way, the somatic nervous system has an important role in responding to sensory stimuli and initiating voluntary motor movements. You will learn more about this in the next lesson of this chapter.

Processes sensory and motor info received from pns

Question 8

Autonomic nervous system

Answer 8

The autonomic nervous system is a division of the peripheral nervous system that regulates visceral muscles, organs, and glands, and transmits neural messages to the central nervous system about their activity.
The autonomic nervous system controls visceral muscles, organs, and glands, which are muscles, organs, and glands not connected to the skeleton that are predominantly self-regulating and do not require conscious control. In this way, the autonomic nervous system is involved
in unconscious responses, which you will learn more about in the next lesson of this chapter.

Not consciously controlled

Question 9

Divisions of the autonomic nervous system

Answer 9

Sympathetic
Parasympathetic

Question 10

Sympathetic and parasympathetic nervous system

Answer 10

Sympathetic nervous system
The sympathetic nervous system is a division of the autonomic nervous system that activates visceral muscles, organs, and glands, preparing the body to respond to a threat or stressor. Sympathetic responses energise the body, enabling it to engage in high levels of physical activity and confront a threatening or stressful situation.
Parasympathetic nervous system
The parasympathetic nervous system is a division of the autonomic nervous system that maintains the optimal and balanced functioning
of visceral muscles, organs, and glands. This involves returning them
to optimal and balanced functioning after experiencing heightened bodily arousal due to sympathetic responses, as well as maintaining homeostasis. If visceral muscles, organs, and glands remained at this increased level
of functioning, even once the threat or stressor is no longer present, bodily resources would become depleted.

Question 11

Neuron and 3 types

Answer 11

A neuron is a nerve cell that receives and transmits neural information. The nervous system is composed of billions of neurons arranged in neural pathways along which neural messages are transmitted. In this way, the neuron is the basic functional unit of the nervous system.
Motor
Sensory
Interneuron

Question 12

Motor sensory and interneuron

Answer 12

Motor neurons (also known as efferent neurons) neurons that transmit neural messages about motor movement from the central nervous system to the peripheral nervous system
Sensory neurons (also known as afferent neurons) neurons that transmit neural messages about bodily sensations from the peripheral nervous system to the central nervous system
Interneurons neurons that transfer neural messages between sensory neurons and motor neurons

Question 13

Efferent v afferent

Answer 13

CNS to pns v pns to cns

Question 14

What made of interneuorns and what’s made of sensory and motor neuron

Answer 14

I: all parts of sensory nervous system
SaM: all past of peripheral ns

Question 15

Viceral organs and glands controlled by autonomic ns

Answer 15

Salivary glands
Lungs
Arteries
Adrenal
Kidney
Intestine
Bladder
Iris (eye)
Heart
Sweat glands
Stomach
Liver
Colon
External sex organs

Question 16

Are neurons the basic functioning unit of the ns

Answer 16

Yes

Question 17

The —- ns controls skeletal muscles whereas the —— ns controls viceral muscles organs and glands

Answer 17

Somatic, autonomic

Question 18

What controls skeletal muscle movements

Answer 18

1The somatic nervous system, which is a division of the peripheral nervous system, controls skeletal muscles.2

Question 19

What controls viceral muscles organs and glands

Answer 19

Autonomic ns

Question 20

Neuron roles

Answer 20

A neuron is a nerve cell that receives and transmits neural information.1There are three types of neurons, which are interneurons, sensory neurons, and motor neurons.2The neuron is the basic functional unit of the nervous system. This is because the nervous system is made up of neurons arranged in neural pathways.3It is along these neural pathways that both sensory and motor neural messages are transmitted around the body, enabling various divisions of the nervous system to communicate with one another.4

Question 21

Conscious response

Answer 21

Conscious responses are deliberate and voluntary actions that are intentionally initiated by the brain and performed by the body. Therefore, conscious responses involve the central nervous system because the brain is a component of the central nervous system. The performance of a conscious response by the body also involves the somatic nervous system, which is a division
of the peripheral nervous system. Table 1 explains how the central nervous system and the somatic nervous system interact to enable conscious responses to internal and external sensory stimuli.

Question 22

Sensory receptors

Answer 22

a nerve ending that detects internal sensations in the body and external sensations from the environment

Question 23

Conscious response to internal and external stimuli

Answer 23

The sensory stimulus comes into contact with sensory receptors, which are nerve endings that detect internal sensations in the body and external sensations from the environment.

This sensory neural message is transmitted via afferent pathways in the somatic nervous system, and then the spinal cord, to the brain.

The brain processes this sensory information, coordinating and initiating a conscious motor response.

This motor neural message is transmitted via efferent pathways in the spinal cord, and then the somatic nervous system,
to skeletal muscles.

The skeletal muscles carry out the conscious motor response to the sensory stimulus.

Question 24

Spinal cord damage

Answer 24

If a person sustains damage to their spinal cord, these neural messages may not
be effectively and efficiently transmitted. This may cause significant sensory impairments, such as numbness and tingling, and significant motor impairments, such as weakness and loss of movement. In extreme cases, the person may experience a complete loss of sensation and mobility below the site of the spinal cord injury.

Question 25

Unconscious response

Answer 25

Unconscious responses are automatic and involuntary actions that are performed by the body independently of the brain. They occur without conscious awareness in response to internal and external sensory stimuli. The unconscious responses that you will learn about are:
• physiological responses of the autonomic nervous system • the spinal reflex.

Question 26

Physiological responses of the autonomic ns

Answer 26

autonomic nervous system, which is a division
of the peripheral nervous system, controls visceral muscles, organs, and glands that are predominantly self-regulating and do not require conscious control. In this way, the autonomic nervous system is involved in the unconscious physiological responses of these visceral muscles, organs, and glands.

The sympathetic nervous system becomes dominant when a person is confronted with a threat or stressor, whereas the parasympathetic nervous system is dominant during rest and physical inactivity. There are different unconscious physiological responses of the visceral muscles, organs, and glands that occur depending on which of these divisions is dominant. When the sympathetic nervous system is dominant, physiological responses occur to energise the body, preparing
it to confront or escape the threat or stressor. When the parasympathetic nervous system is dominant, physiological responses occur that maintain optimal and balanced functioning.

Question 27

Physiological unconscious responses of autonomic ns

Answer 27

Sympathetic responses:
• Heart rate increases to increase blood flow, enabling high levels of physical activity.
• Breathing rate increases and lung airways
expand to increase oxygenation, enabling
high levels of physical activity.
• Pupils dilate to allow more light to enter
the eyes, improving vision.
• Adrenal glands secrete stress hormones,
such as adrenaline, to energise the body.
• Sweat glands are activated, increasing
perspiration.
• Digestion is inhibited to conserve energy
required for high levels of physical activity.
• The bladder relaxes to conserve energy,
enabling this energy to be directed to other bodily processes that need it more during high levels of physical activity.
• The body releases more glucose to energise the body.
Parasympathetic:
• The heart beats at a steady and regular rate that supports optimal and balanced functioning.
• Lung airways constrict, enabling a steady and regular breathing rate.
• Pupils constrict according to external light levels, allowing an appropriate amount of light to enter the eyes for adequate vision.
• Adrenal glands do not secrete stress hormones, such as adrenaline, to allow the body to rest.
• Sweat glands are regulated, controlling perspiration.
• Digestion occurs normally, enabling food to be metabolised by the body.
• The bladder constricts and urination is controlled.
• The body releases less glucose to allow the body to rest and prevent the depletion of energy stores.

Question 28

Fight or flight

Answer 28

flight-or-fight-or-freeze response, which is an involuntary response that occurs when a person is confronted by a threat or stressor. This response involves the unconscious physiological responses of the sympathetic nervous system,

Question 29

What response is performed at rest v at stress

Answer 29

Rest: unconscious physiological responses of the parasympathetic nervous system occurred as your body maintained optimal and balanced functioning.
Stress: unconscious physiological responses of the sympathetic nervous system occurred as your body reacted to the threat or stressor.

Question 30

Spinal reflex

Answer 30

an unconscious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain.

The spinal reflex occurs automatically and involuntarily. This unconscious response requires less processing than conscious responses because it is immediately initiated by the spinal cord in response to sensory stimuli, rather than consciously processed by the brain. Furthermore, the neural signal involved in the spinal reflex travels a shorter distance to the spinal cord
than conscious responses do to the brain. In this way, the spinal reflex has evolved to protect humans from harm, enabling them to quickly and immediately respond to danger before they have even consciously registered it.

Question 31

Spinal reflex explanation

Answer 31

A dangerous or harmful sensory stimulus is detected by sensory receptors,
which transmit this sensory message via sensory neurons in the somatic nervous system to the spinal cord.

An interneuron in the spinal cord immediately relays this sensory neural signal from a sensory neuron to
a motor neuron as a motor neural signal, initiating an automatic and unconscious motor response.

The motor message is transmitted via motor neurons in the somatic nervous system to skeletal muscles, which carry out this unconscious motor response to the dangerous or harmful sensory stimulus.

The sensory message continues to travel via afferent tracts in the spinal cord to the brain. Then, the brain independently registers the sensation that triggered the spinal reflex.

Question 32

Reflex arc

Answer 32

The path along which the neural signal is transmitted as part of the spinal reflex is called the reflex arc. The sensory neural message travels from sensory receptors to the spinal cord. It then loops around at the spinal cord, and, now as a motor neural message, travels from the spinal cord to skeletal muscles, which completes the reflex arc.

Question 33

Tip

Answer 33

Some exam questions may require you to identify whether the response described in a scenario is conscious or unconscious. There are specific words to look out for that indicate the type of response. For example, imagine a scenario that describes a person withdrawing their hand after touching an object. If the scenario states that the person ‘decides’ to withdraw their hand, this implies that the response is conscious. By contrast, if the scenario states that the person ‘immediately’ withdraws their hand, this implies that the response is unconscious.

Question 34

Why enables certain responses to sensory stimuli

Answer 34

Conscious: Enabled by the somatic nervous system (PNS) and the CNS
Unconscious>
-physiological: Enabled by the autonomic nervous system (PNS)
-spinal reflex: Enabled by the somatic nervous system (PNS) and the spinal cord in the CNS
Sympathetic (physiological): Enabled by the sympathetic nervous system (PNS)
Parasympathetic (physiological): Enabled by the parasympathetic nervous system (PNS)

Question 35

What initiates conscious response

Answer 35

Bain

Question 36

What subdivision enables conscious response

Answer 36

Somatic ns and central nervous system

Question 37

What enable unconscious responses

Answer 37

Autonomic ns

Question 38

What is the spinal cord initiated by

Answer 38

Interneurons

Question 39

Is spinal reflex conscious or not

Answer 39

Not

Question 40

Similarities and difference between conscious motor response to sensory stimuli and spinal reflex

Answer 40

Both conscious motor responses to sensory stimuli and the spinal reflex are initiated by the central nervous system.1However, these responses are initiated by different components of the central nervous system, with conscious motor responses being initiated by the brain and the spinal reflex being initiated by the spinal cord.2

Question 41

How nervous system can coordinate the conscious response of putting on a jacket when feeling cold

Answer 41

Sensory receptors on the person’s skin would detect the sensation of the cold weather.1This sensory information would be transmitted via sensory neural pathways in the somatic nervous system and afferent tracts in the spinal cord to the brain.2The brain would receive and process this sensory neural message of the cold weather, and coordinate and initiate a conscious motor response to put on a jacket.3This motor neural message would be transmitted via efferent tracts in the spinal cord and motor neural pathways in the somatic nervous system to skeletal muscles, which would carry out the motor movement of putting on a jacket in response to the cold weather.

Question 42

When explaining a response…

Answer 42

State conscious or unconscious
State motor or sensory