Unit 3 - The Nervous System Flashcards

1
Q

Describe six functions of the nervous system.

A

Coordinates movement. It plans, initiates, and asserts ongoing control over every move you make.
** Processes sensory input.** This amazingly diverse category includes smell, vision, taste, hearing, and somatosensory information (pain, warmth, an itch you need to scratch…) These functions allow you to receive and interpret information from your joints, ligaments, muscles, and skin.
**Initiates and maintains life-sustaining functions. **These include your innate need to find water, food, and a mate.
Learns and forms memories: Learning and memory are the primary elements of cognition.
Experiences emotions: These include feelings of fear, pleasure, attachment, and drive.
Controls arousal: Consciousness and sleep regulation are parts of this function.

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2
Q

Describe six functions of the nervous system.

A

Coordinates movement: It plans, initiates, and asserts ongoing control over every move you make.
** Processes sensory input**: This amazingly diverse category includes smell, vision, taste, hearing, and somatosensory information (pain, warmth, an itch you need to scratch…) These functions allow you to receive and interpret information from your joints, ligaments, muscles, and skin.
**Initiates and maintains life-sustaining functions. **These include your innate need to find water, food, and a mate.
Learns and forms memories: Learning and memory are the primary elements of cognition.
Experiences emotions: These include feelings of fear, pleasure, attachment, and drive.
Controls arousal: Consciousness and sleep regulation are parts of this function.

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3
Q

The nervous system are divided into these two systems?

A

The central nervous system (CNS) and peripheral nervous system

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4
Q

Define:

Central nervous system (CNS)

A

The nervous system cells that make up the brain and spinal cord.

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5
Q

Define:

Peripheral nervous system (PNS)

A

The nervous system cells that provide information to the brain and spinal cord.

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6
Q

The nervous system consists mainly of which two cells? In avergare how many are there of each?

A

Neurons: 86 billions
Glia: 1 trillion

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7
Q

Define:

Neuron

A

The nervous system cell that produces action potentials to communicate with other neurons, muscles, or glands.

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7
Q

Define:

Glia

A

The nervous system cell that protects and supports neurons but does not produce action potentials.

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8
Q

Define:

Action potential

A

The electrical signal produced by a neuron or muscle spindle.

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9
Q

Which kind of neuron are there in the human nervous system?

A

Motor neurons
Sensory neurons
Interneurons

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10
Q

Define:

Motor neurons

A

A nervous system cell that transmits information away from the spinal cord to muscles or glands.

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11
Q

Define:

Sensory neurons

A

A nervous system cell that transmits information regarding movement, sight, touch, sound, and smell to the brain and spinal cord.

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12
Q

Define:

Interneurons

A

A nervous system cell that creates circuits between motor or sensory neurons, and within the brain and spinal cord.

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13
Q

Define:

Dendrites

A

The portion of a neuron that receives information from other neurons.

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14
Q

In the context of neurons, define cell body

A

The cell body, or soma, is the bulbous end of a neuron that contains the nucleus (DNA). This part of the neuron integrates information and determines whether there’s enough to create an action potential.

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15
Q

Define:

Axon

A

The axon is the transmitter portion, relaying signals to other neurons, muscles, or organs. The axons that travel from the spinal cord to the feet can be up to a meter long but just 100 microns (a tenth of a millimeter) wide.

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16
Q

Define:

Muscle spindle

A

A muscle spindle is a sensory receptor within muscle that detects changes in length and helps regulate contraction. It sends information to the sensory cell body. The information then travels through the axon to the spinal cord, where it communicates with motor neurons or interneurons.

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17
Q

Define:

Synapse

A

An area between neurons, or between a neuron and muscles or glands, where electrical or chemical signals are transmitted.

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18
Q

Define:

Acetylcholine

A

The chemical (a neurotransmitter) a motor neuron releases to cause muscle contractions.

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19
Q

Define:

Neuromuscular junction

A

The area between a motor neuron and muscle fiber where acetylcholine is released.

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20
Q

Define:

Myelin

A

A fatty sheath around the axon of a nerve that provides electrical insulation, protection, nourishment, and faster signal transmission.

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21
Q

How fast can signals travel through a nerve?

A

Up to 90 m/s

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22
Q

The Peripheral Nervous system (PNS) can be divided into which systems?

A

The PNS can be further subdivided into the somatic nervous system and autonomic nervous system.

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23
Q

Define:

Somatic nervous system

A

The division of the peripheral nervous system that controls voluntary movement.

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24
Q

Define:

Autonomic nervous system

A

The division of the peripheral nervous system that controls subconscious actions such as breathing, heart rate, and digestive processes.

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25
Q

The Automatic Nervous System can be divided into which subsystems?

A

It’s further divided into the sympathetic and parasympathetic nervous systems.

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26
Q

Define:

Sympathetic nervous system

A

The division of the autonomic nervous system that generates the “fight or flight” response.

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27
Q

Define:

Parasympathetic nervous system

A

The division of the autonomic nervous system that generates the “rest or digest” response.

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28
Q

Define:

Norepinephrine

A

The hormone/neurotransmitter released by the CNS and sympathetic nervous system that triggers the “fight or flight” response.

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29
Q

Describe:

The forebrain

A

The forebrain includes the cerebrum, which helps learn and control movement, and the diencephalon, which relays and integrates information from different parts of the brain and spinal cord. The cerebrum is further divided into right and left cerebral hemispheres, which are connected by the corpus callosum.

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30
Q

Describe:

The brainstem

A

The brainstem consists of the midbrain, pons, and medulla. It mediates sensory and motor control of the head, neck, and face along with balance. The brainstem also contains the sensory and motor pathways that travel to other parts of the CNS..

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31
Q

Describe:

The cerebellum

A

The cerebellum (which literally means “little brain”) plans and coordinates movement. It contains more densely packed neurons than does any other subdivision of the brain.

32
Q

Describe:

The spinal cord

A

The spinal cord transmits motor information down from the brain and sensory information up to the brain. It also contains reflex circuits.

33
Q

Define:

Homeostasis

A

The process of keeping physiological systems stable.

34
Q

Define:

Corpus callosum

A

Neural fibers that connect the right and left cerebral hemispheres.

35
Q

Define:

White matter

In the context of the human nervous system

A

The portion of the brain and spinal cord that contain myelinated axons.

Myelin are white in color

36
Q

Define:

Grey matter

In the context of the human nervous system

A

The portion of the brain and spinal cord that contain axons with little or no myelin and cell bodies.

37
Q

Define:

Meninges

A

The membranes that cover the brain and spinal cord to provide protection and nourishment.

38
Q

Define:

Cerebrospinal fluid (CSF)

A

A clear fluid found in the brain and spinal cord that protects and cleans the brain.

39
Q

Define:

Ventricles

In the context of the human nervous system

A

Cavities in the brain that contain cerebrospinal fluid.

40
Q

Where do the spinal cord end?

A

The spinal cord ends around the second lumbar vertebrae (L2). The area between L2 and the sacrum is filled with bundles of spinal nerves, known as the cauda equina. They extend to the bottom of the sacrum and innervate the muscles of the hips, legs, pelvic organs, and sphincter.

41
Q

Define:

Cauda equina

A

A bundle of spinal nerves that begin around the second lumbar vertebrae where the spinal cord ends.

42
Q

Specify the size of the spinal cord and its enlargements.

A

The spinal cord is usually 15 to 19 inches long, depending on a person’s height, and approximately one-half inch across at its narrowest section. The diameter increases in two areas: The cervical enlargement is wider because it contains the nerves that travel to the arms, whereas the lumbar enlargement holds the nerves that travel to the legs. Both structures provide more room for additional cell bodies.

43
Q

Define:

Cervical enlargement

A

The larger diameter area of the spinal cord that contains the nerves that travel to the upper limbs.

44
Q

Define:

Lumbar enlargement

A

The larger diameter area of the spinal cord that contains the nerves that travel to the lower limbs.

45
Q

Define:

Sensory nerve

A

A bundle of axons that carries sensory information into the brain or spinal cord.

46
Q

What is another name for a sensory nerve?

A

Afferent nerve

47
Q

Define:

Motor nerve

A

A bundle of axons that carries motor information away from the brain or spinal cord to muscles or glands.

48
Q

What is another name for a motor nerve?

A

Efferent nerve

49
Q

Define:

Mixed nerve

A

A bundle of axons that carries sensory, motor, and autonomic information.

50
Q

How many spinal nerves are there n the human spinal column? How can they be grouped?

A

Thirty-one pairs of spinal nerves emerge from the spinal cord to control muscles in the body, from the neck down to the toes. They’re divided into regions that correspond with the vertebrae from which they exit, giving you 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves, and 1 pair of coccygeal nerves.

51
Q

Desribe:

Cranial nerves

A

Twelve pairs of nerves that emerge from the brain or brainstem to relay pure sensory, pure motor, or sensory and motor information to the head.

52
Q

Why are there eight pairs of cervical nerves?

A

The C1 spinal nerve exits above the C1 vertebrae and the C2 spinal nerve above the C2 vertebrae, and this above-the-vertebrae arrangement continues until the final C7 vertebrae. That allows room beneath the C7 vertebrae for an extra spinal nerve, and then the below-the-vertebrae arrangement continues down the rest of the vertebral column.

53
Q

Define:

Lower motor neuron

A

A peripheral nervous system cell whose cell body is in the brainstem or spinal cord that innervates muscles or glands.

54
Q

Define:

Motor unit

A

A lower motor neuron and all the muscle fibers it innervates.

55
Q

Define

Henneman’s size principle

A

The fixed, orderly recruitment of motor neurons from smallest to largest.

56
Q

Define:

Motor unit pool

A

A vertical column of cell bodies within the spinal cord that innervate a single muscle. Thos column can span several segemenst (vertebrae).

57
Q

Upper motor neuron

A

A central nervous system cell that synapses with lower motor neurons.

58
Q

Define:

Cerebral cortex

A

The outermost layer of the brain.

59
Q

Define:

Motor cortex

A

The region of the brain consisting of the premotor cortex, primary motor cortex, and supplementary motor area that primarily controls movement.

60
Q

Define:

Neural tract

A

A bundle of axons within the CNS that carries motor or sensory information.

61
Q

Define:

Descending tract

A

A bundle of axons within the CNS that carries motor or sensory information.

62
Q

Define:

Ascending tract

A

A bundle of axons that carry sensory information through the spinal cord to the brain.

63
Q

How many descending tracts are there? Where do they origin and what is their purpose?

A

Within the brain are eight descending tracts per side formed by the axons of upper motor neurons. Three originate in the motor cortex; they’re charged with planning, initiating, and directing movement. The others, which originate in the brainstem, control facial movement and posture. Those are mostly involuntary reflex actions.

64
Q

Define:

Proprioceptors

A

Sensory receptors in the muscles and joints that transmit information to the CNS.

65
Q

Define:

Pyramidal tract

A

A pathway from the motor cortex that helps regulate voluntary movement.

66
Q

Define:

Extrapyrimidal tract

A

A pathway from the brainstem that helps regulate involuntary movement.

67
Q

How many ascending tracts are there? What are their purpose?

A

There are five ascending tracts per side that carry sensory information through the spinal cord up to the brain. Collectively, they communicate the sensations of proprioception, touch, pain, pressure, and vibration.

68
Q

Define:

Muscle spindle

A

A sensory receptor within the skeletal muscle belly that detects changes in muscle length.

69
Q

Define:

Golgi tendon organ (GTO)

A

A sensory receptor within the tendons of a muscle that detects changes in muscle tension.

70
Q

Define:

Alpha-gamma co-activation:

A

A process that allows a muscle spindle to contract at the same rate as the muscle where it resides.

71
Q

Describe how the muscle spindle works.

A

When a muscle lengthens rapidly, a potentially injurious action, the muscle spindle sends a distress signal into the spinal cord. There it forms two synapses: one with the muscle that’s being stretched and the other with its antagonist. This reciprocal innervation causes the muscle that’s being stretched to contract and its antagonist to relax.

72
Q

Define:

Stretch reflex

A

A neural circuit that allows activation of a muscle to occur with simultaneous relaxation of its antagonist.

73
Q

Define:

Basal ganglia

A

Structures within the cerebrum that communicate with the motor cortex to help initiate movement.

74
Q

Define:

Parkinson’s disease

A

A movement disorder caused by a deficiency of dopamine in the basal ganglia.

75
Q

Define:

Huntington’s disease

A

A movement disorder caused by damage to the cells of the basal ganglia.

76
Q

In relation to voluntary movement, what is the role of the cerebellum?

A

The cerebellum both initiates and predicts movement. It then compares the actual motion to what it predicted and uses that information both to fine-tune the movement while it happens and to make better predictions in the future. Therefore, although it doesn’t directly control movement, the cerebellum influences movement in real time and works to make sure the movement is performed a little better the next time around.

77
Q

Defne:

Neuroplasticity

A

The brain’s ability to form new connections.

78
Q

What are the limitation of neuroplasticity in relation to movement?

A

The changes only occur if the movement or exercise is novel and challenging. Easy exercises won’t have the same effect.