Nervous System Chapter 12 Flashcards

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Questions and Answers

What is a neuron?

A type of bone cell
A nerve cell; the basic building block of the nervous system (correct)
A brain cell
A type of muscle cell

What are astrocytes?

Neurons that transmit signals
Star-shaped glial cells in the brain and spinal cord (correct)
Types of neurotransmitters
Muscle cells

What is the function of an axon hillock?

It is the part connecting soma and axon, where membrane potentials are summated before being transmitted to the axon.

What differentiates general senses from special senses?

General senses include nociceptors and thermoreceptors; special senses include olfactory and auditory. (D) Signup and view all the answers

What is grey matter?

Major component of CNS; unmyelinated sheaths, somas, glial cells, synapses, capillaries. Signup and view all the answers

What is white matter?

Myelinated axons that connect grey matter and carry nerve impulses to neurons. Signup and view all the answers

Define monosynaptic reflex.

Knee-jerk reaction; transmission of info from a sensory neuron to the appropriate motor neuron through a single synapse in the spinal cord. Signup and view all the answers

What is a polysynaptic reflex?

A reflex that involves one or more interneurons connecting afferent and efferent signals. Signup and view all the answers

What is the role of a somatic motor neuron?

It carries impulses to skeletal muscles and is involved in reflex arcs. Signup and view all the answers

What are the primary functions of sympathetic neurons?

Both B and C (A) Signup and view all the answers

What are visceral sensory neurons part of?

The autonomic nervous system. Signup and view all the answers

Describe a bipolar neuron.

A neuron with two extensions; specialized for the transmission of special senses. Signup and view all the answers

What characterizes a multipolar neuron?

It possesses one axon and many dendrites. Signup and view all the answers

What is the function of glial cells?

They surround neurons and provide support and insulation. Signup and view all the answers

What is the brain's primary role?

Controls and coordinates activities of the nervous system. Signup and view all the answers

What does CNS stand for?

Central Nervous System. Signup and view all the answers

What does PNS stand for?

Peripheral Nervous System. Signup and view all the answers

What are autonomic nerves responsible for?

They serve the internal organs of the body. Signup and view all the answers

What is a nerve impulse?

A message that travels from the dendrites of a neuron to the axon. Signup and view all the answers

Define an axon.

A long nerve fiber that conducts away from the cell body of the neuron. Signup and view all the answers

What is a dendrite?

The branching extensions of a neuron that receive messages and conduct impulses toward the cell body. Signup and view all the answers

What are Schwann cells?

Large nucleated cells that form myelin around the axons of neurons. Signup and view all the answers

What is the node of Ranvier?

A small gap between myelinated segments where the axonal membrane is exposed. Signup and view all the answers

What occurs at a synapse?

Neurotransmitters travel across the space between two neurons. Signup and view all the answers

What is the role of receptors?

To receive information about changes in the environment. Signup and view all the answers

Define effectors in the nervous system.

Muscles or glands that respond to impulses. Signup and view all the answers

What is a stimulus?

Something that causes a response. Signup and view all the answers

What is the cell body of a neuron?

Contains the major concentration of the cytoplasm and the nucleus of the neuron. Signup and view all the answers

What is myelin?

An electrically-insulating phospholipid layer that surrounds the axons of many neurons. Signup and view all the answers

Define reflex.

A relatively simple, involuntary response to a stimulus. Signup and view all the answers

What is resting potential?

The potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse. Signup and view all the answers

What is action potential?

A change in electrical potential that occurs between the inside and outside of a nerve or muscle fiber when it is stimulated. Signup and view all the answers

Define refractory period.

The time after a neuron fires during which a stimulus will not evoke a response. Signup and view all the answers

What is a neurotransmitter?

A chemical messenger that travels across the synapse from one neuron to the next. Signup and view all the answers

What is the spinal cord?

Part of the central nervous system that links the brain to the rest of the body. Signup and view all the answers

What is the cerebellum responsible for?

Balance and coordination. Signup and view all the answers

What is the cerebrum?

The largest part of the brain, controls thinking, reasoning, and memory. Signup and view all the answers

What is the corpus callosum?

Connects the hemispheres; allows them to share information. Signup and view all the answers

What is the role of the pons?

Relay link between the brain and spinal cord. Signup and view all the answers

What does the medulla oblongata regulate?

Heart rhythm, blood flow, and breathing rate. Signup and view all the answers

What are endorphins?

Natural neurotransmitters linked to pain control. Signup and view all the answers

What is the retina?

The light-sensitive layer of the eye composed of receptors (rods and cones). Signup and view all the answers

What are rods?

Rod-shaped receptors in the retina sensitive to dim light but not color. Signup and view all the answers

What are cones?

Receptor cells in the retina that are sensitive to bright light and produce color vision. Signup and view all the answers

What is the pinna?

The visible part of the outer ear that collects sound. Signup and view all the answers

What is the eardrum?

The membrane that separates the outer ear from the middle ear and vibrates when sound waves strike it. Signup and view all the answers

What is the cochlea?

A coiled tube in the inner ear essential for hearing. Signup and view all the answers

What are olfactory cells?

Sensitive nerve cells in the nasal passages. Signup and view all the answers

What is the autonomic nervous system?

The part of the nervous system that controls involuntary actions and responses. Signup and view all the answers

What are eustachian tubes?

Tubes connecting the ear to the throat; helps to equalize pressure. Signup and view all the answers

Define Parkinson's Disease.

A progressive disease that destroys brain cells leading to muscular tremors and slowing of movement. Signup and view all the answers

What is Alzheimer's Disease?

A disease that results in progressive loss of memory and mental capacity. Signup and view all the answers

Define ALS.

Lou Gehrig's Disease; a progressive neurological disease leading to total loss of motor function. Signup and view all the answers

What is Multiple Sclerosis?

A disorder in which myelin is destroyed causing loss of motor activity. Signup and view all the answers

Study Notes

Neuron and Glial Cells

Neurons are the essential nerve cells that form the basis of the nervous system.
Astrocytes are star-shaped glial cells located in the brain and spinal cord, playing a key supportive role.

Neuron Structure

The axon hillock is the junction where the cell body (soma) meets the axon; it is crucial for summing membrane potentials.
Dendrites are extensions that receive signals and direct impulses toward the cell body.
The axon conducts impulses away from the neuron’s cell body, while action potentials are changes in electrical potential during stimulation.

Nervous System Components

Grey matter consists of unmyelinated sheaths, cell bodies, synapses, and capillaries, primarily found in the CNS.
White matter contains myelinated axons that facilitate communication between different grey matter regions.

Reflexes

Monosynaptic reflexes involve a direct connection between sensory and motor neurons, exemplified by the knee-jerk reflex.
Polysynaptic reflexes engage one or more interneurons for processing sensory input, as seen with pain responses (e.g., touching a hot surface).

Types of Neurons

Somatic motor neurons control voluntary movements, linking sensory input with motor responses.
Bipolar neurons have two extensions and are involved in transmitting special sensory information; they are specialized for smell, sight, taste, hearing, and vestibular functions.
Multipolar neurons, the most abundant in the CNS, have one axon and multiple dendrites.

Autonomic Nervous System

The autonomic nervous system (ANS) manages involuntary activities, with visceral sensory neurons sending signals from internal organs.
Sympathetic neurons support the "Fight or Flight" response with short first and long second axons, while parasympathetic neurons facilitate "Rest and Digest" functions through long first and short second axons.

Brain and Spinal Components

The brain coordinates nervous system activities and includes structures such as the cerebrum (thinking) and cerebellum (balance).
The spinal cord links the brain with the rest of the body, playing a vital role in reflex arcs.

Action Potentials and Synaptic Transmission

Resting potential refers to the electrical difference across a neuron's membrane when inactive.
Neurotransmitters are chemical messengers that cross synapses, influencing whether an action potential will occur.

Sensory organs and receptors

The retina contains rods and cones, crucial for vision; rods detect dim light, while cones enable color vision.
The pinna collects sound waves and channels them into the auditory canal, leading to the eardrum, which vibrates in response to sound.

Neurological Disorders

Parkinson's Disease results in tremors and movement difficulties due to neurodegeneration.
Alzheimer's Disease leads to progressive memory loss and cognitive decline.
ALS, or Lou Gehrig's Disease, progressively impacts motor neurons without affecting cognitive function.
Multiple Sclerosis involves the destruction of myelin, disrupting motor activity.

Supporting Structures

Schwann cells form myelin around axons, while nodes of Ranvier are gaps in the myelin sheath that enhance impulse speed.
Eustachian tubes connect the ear to the throat, helping to equalize pressure within the ear.

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Test your knowledge of the nervous system with these flashcards covering key terms such as neurons and astrocytes. This quiz helps reinforce your understanding of the structure and function of the nervous system components. Perfect for students studying neuroscience or biological sciences.