Nervous System

Question 1

Nervous system

Answer 1

-Senses, interprets, and issues commands as a response to conditions in the body’s environment
-this process is made possible by very complex communication system organized as a grid of neurons
-messages are sent across the plasma membrane of neurons through a process called action potential
-these messages occur when a neuron is stimulated past a necessary threshold
-the stimulations occur in a sequence from the stimulation point of one neuron to its contact with another neuron
-at the point of contact, called a chemical synapse, a substance is released that stimulates or inhibits the action of the adjoining cell
-this network fans out across the body and forms the framework for the nervous system
-the direction of the information flows depends on the specific organizations of nerve circuits and pathways

Question 2

Three functional types of neurons

Answer 2

Sensory neurons
Motor neurons
Interneurons

Question 3

Sensory neurons

Answer 3

Transmit signals to the central nervous system (CNS) from the sensory receptors associated with touch, pain, temperature, hearing, sight, smell, and taste

Question 4

Motor neurons

Answer 4

Transmit signals from the CNS to the rest of the body such as by signaling muscles or glands to respond

Question 5

Interneurons

Answer 5

Transmit signals between neurons
-ex. Interneurons receive transmitted signals between sensory neurons and motor neurons

Question 6

In general, a neuron consists of three basic parts

Answer 6

Cell body
axon
dendrites

Question 7

Cell body (soma)

Answer 7

Contains the nucleus of the neuron

Question 8

Axon

Answer 8

-Transmits the impulses away from the cell body
-the axon is insulated by oligodendrocytes and the myelin sheath with gaps known as the nodes of Ranvier
-the axon terminates at the synapse

Question 9

Question 10

CNS

Answer 10

Consists of brain and spinal cord

Question 11

[CNS]
Spinal cord

Answer 11

-Spinal cord is encases in the bony structure of the vertebrae, which protects and supports it
-it’s nervous tissue functions mainly with respect to limb movement and internal organ activity
-major nerve tracts ascend and descend from the spinal cord to the brain

Question 12

[CNS]
Brain

Answer 12

Brain consists of the hindbrain, midbrain, and forebrain

Question 13

[CNS]
Brain: HINDBRAIN

Answer 13

The hindbrain includes the medulla oblongata, cerebellum, and pons

Question 14

[CNS]
Brain: MIDBRAIN

Answer 14

-The midbrain integrates sensory signals and orchestrates responses to these signals
-The midbrain is associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation, acting as a sort of relay station for auditory and visual information.

Question 15

[CNS]
Brain: FOREBRAIN

Answer 15

The forebrain includes the cerebrum, thalamus, and hypothalamus

Question 16

[CNS]
Brain: FOREBRAIN—CEREBRAL CORTEX

Answer 16

The cerebral cortex is a thin layer of gray matter covering the cerebrum

Question 17

[CNS]
Brain lobes

Answer 17

The brain is divided into four main lobes, the frontal lobe, the parietal lobe, the occipital lobe,and the temporal lobe

Question 18

[CNS]
Brain lobes: FRONTAL

Answer 18

The frontal lobe is located in the front of the brain is responsible for a short term and working memory and information processing as well as decision-making, planning, and judgment

Question 19

[CNS]
Brain lobes: PARIETAL

Answer 19

The parietal lobe is located slightly toward the back of the brain and the top of the head and is responsible for sensory input as well as spatial positioning of the body

Question 20

[CNS]
Brain lobes: OCCIPITAL

Answer 20

-The occipital lobe is located at the back of the head, just above the brain stem
-this lobe is responsible for visual input, processing, and output, specifically, nerves from the eyes enter directly into this lobe

Question 21

[CNS]
Brain: CEREBELLUM

Answer 21

-The cerebellum plays a role in the processing and storing of implicit memories
-specifically, for those memories developed in classical-conditioning learning techniques
-the role of the cerebellum was discovered by exploring the memory of individuals with damaged cerebellums -these individuals were unable to develop stimulus responses when presented via a classical conditioning technique
-researchers found that this was also the case for automatic responses
-ex. when these individuals were presented with a puff of air into their eyes, they did not blink, which would have been a naturally occurring and automatic response in an individual with no brain damage

Question 22

[CNS]
Brain: BRAINSTEM

Answer 22

-the posterior area of the brain that is connected to the spinal cord is known as the brainstem
-the midbrain, the pons, and the medulla oblongata are the three parts of the brain stem
-information from the body is sent to the brain through the brainstem, and information from the brain is sent to the body through the brainstem
-the brainstem is an important part of respiratory, digestive, and circulatory functions

Question 23

[CNS]
Brain: MIDBRAIN

Answer 23

-the midbrain lies above the pons and medulla oblongata
-the parts of the midbrain include the tectum, the tegmentum, and the ventral tegmentum.
-The midbrain is an important part of vision and hearing
-the pons comes between the midbrain and the medulla oblongata
-information is sent across the pons from the cerebrum to the medulla and the cerebellum
-the medulla oblongata (or medulla) is beneath the midbrain and the pons
-the medulla oblongata is the piece of the brainstem that connects the spinal cord to the brain
-so, it has an important role with the autonomic nervous system in the circulatory and respiratory system

Question 24

PNS

Answer 24

Consists of the nerves and ganglia throughout the body and include sympathetic nerves that trigger the “fight or flight” response, and the parasympathetic nerves which control basic body functions

Question 25

PNS Sympathetic nerves

Answer 25

Control fight or flight response

Question 26

PNS Parasympathetic nerves

Answer 26

Control basic body function

Question 27

Autonomic Nervous System [ANS]

Answer 27

-Maintains homeostasis within the body -controls the functions of the internal organs, blood vessels, smooth muscle tissues, and glands -this is accomplished through the direction of the hypothalamus, which is located above the midbrain

Question 28

[ANS] Hypothalamus

Answer 28

-hypothalamus controls the ANS through the brainstem -with this direction from the hypothalamus, the ANS helps maintain a stable body environment (homeostasis) by regulating numerous factors including heart rate, breathing rate, body temperature, and blood pH

Question 29

[ANS] Consists of two divisions

Answer 29

The sympathetic nervous system and the parasympathetic nervous system

Question 30

[ANS] Sympathetic nervous system

Answer 30

-Controls the body‘s reaction to extreme, stressful, and emergency situations -ex. the sympathetic nervous system increases the heart rate, signals the adrenal glands to secrete adrenaline, triggers the dilation of pupils, and slows digestion

Question 31

[ANS] Parasympathetic nervous system

Answer 31

-counteracts the effects of the sympathetic nervous system -ex. the parasympathetic nervous system decreases the heart rate, signals the adrenal glands to stop secreting adrenaline, constrict the pupils, and returns the digestion process to normal

Question 32

Somatic Nervous System [SNS]

Answer 32

-Controls the five senses and the voluntary movement of skeletal muscle -this system has all of the neurons that are connected to sense organs -efferent (motor) and afferent (sensory) nerves health of somatic nervous system operate the senses and the movement of skeletal muscle

Question 33

[SNS] Efferent nerves

Answer 33

Bring signals from the central nervous system to the sensory organs and the muscles

Question 34

[SNS] Afferent nerves

Answer 34

-bring signals from the sensory organs and the muscles to the central nervous system -the somatic nervous system also performs in voluntary movements which are known as reflex arts

Question 35

Reflex

Answer 35

-Simplest act of the nervous system -an automatic response without any conscious thought to a stimulus via the reflex arc

Question 36

Reflex arc

Answer 36

-Simplest nerve pathway, which bypasses the brain and is controlled by the spinal cord -ex. the classic knee-jerk response (patellar tendon reflex), the stimulus is the reflex hammer hitting the tendon, and the response is the muscle contracting, which jerks the foot upward -the stimulus is detected by sensory receptors, and a message is sent along a sensory (afferent) neuron to one or more interneurons in the spinal cord -the interneurons transmit this message to a motor (efferent) neuron, which carries the message to the correct effector (muscle)