Exercise physiology chapter 7: nervous system

The _____ system is the body's means of perceiving and responding to events in the internal and external environments.

The _____ system is the body's means of perceiving and responding to events in the internal and external environments.

Nervous

_____ refers to the supply of nerves to a particular organ.

Innervention

Match the nerve fibers in the peripheral nervous system with their descriptions
Sensory nerve fibers
Motor nerve fibers

Sensory nerve fibers - conduct information towards CNS
Motor nerve fibers - conduct information from the CNS

The functional unit of the nervous system is the

neuron

T/F Each neuron has only one axon; however, the axon can divide into several collateral branches that terminate at other neurons, muscle cells, or glands.

True

Receptors capable of sensing touch, pain, temperature changes, and chemical stimuli send information to the _____ nervous system concerning changes in environment.

Central

In large nerve fibers, like those innervating skeletal muscles, the axons are covered with an insulating layer of cells called _____.

Schwann cells

Match the parts of the nervous system with their descriptions
Central nervous system
Peripheral nervous system

Central nervous system - contained in the skull (brain) and spinal cord
Peripheral nervous system - consists of nerve cells (neurons) outside the skull and spinal cord

T/F Neurons are considered excitable tissue because of their properties of irritability and conductivity.

True

Match the types of fibers with their role
Afferent neurons
Efferent neurons

Afferent neurons - conduct information towards CNS
Efferent neurons - conduct information away CNS

A neuron is polarized at rest and the electrical charge difference between the outer and inner sides of the neuron is called the

resting membrane potential

Match the regions of the neuron with their descriptions
Cell body
Dendrites
Axon

Cell body - Center of operation for the neuron that contains the nucleus
Dendrites - Serve as a receptive area that can conduct electrical impulses toward the cell body
Axon - Carries the electrical message away from the cell body toward another neuron or effector organ

A factor that is important in determining the magnitude of the resting membrane potential of a cell is the _____.

difference in ion concentrations between the intracellular and extracellular fluids

Contact points between an axon of one neuron and the dendrite of another neuron are called _____.

Synapse

A resting neuron has a negative membrane potential because the concentration gradient promotes the movement of _____ ions out of the cell.

Potassium

The membranes of Schwann cells contain a large amount of a lipid-protein substance called _____.

myelin

Select all that apply
The cell membrane has a sodium or potassium pump that uses energy from adenosine triphosphate and maintains the concentration gradients required for the resting membrane potential. Identify the exchange that occurs during this process.

sodium ions leave the cell
potassium ions enter the cell

Match the specialized properties of neurons with their descriptions
Irritability
Conductivity

Irritability - It is the ability of the dendrites and neuron cell body to respond to a stimulus and convert it to a neural impulse
Conductivity - It is the transmission of a neural impulse along the axon.
It is the transmission of a neural impulse along the axon

During the generation of an action potential, depolarization of the cell occurs when _____ gates open.

sodium

At rest, all cells including neurons are _____.

negatively charged

The all-or-none law of action potentials states that _____.

a nerve impulse will travel the entire length of an axon without a decrease in voltage when initiated

The magnitude of the resting membrane potential of a cell is primarily determined by the _____.

permeability of the membrane to different ions

Chemical messengers used by neurons to communicate with each other during the process of synaptic transmission are called _____.

neurotransmitters

A reason for the negative membrane potential in a resting neuron is the higher permeability of the membrane for _____.

potassium than sodium

Excitatory postsynaptic potentials result in depolarization of the postsynaptic neuron to its threshold leading to the _____.

generation of an action potential

The sodium or potassium pump in a cell membrane helps to generate the resting membrane potential by exchanging _____.

three sodium ions for every two potassium ions

An action potential or nerve impulse is generated when _____.

depolarization reaches a critical value called threshold

The summing of several excitatory postsynaptic potentials (EPSPs) from a single presynaptic neuron over a short time period is termed .

temporal summation

T/F A neural impulse will start out strong and will gradually weaken after traveling the length of the axon

false

After release into the synaptic cleft, some neurotransmitters cause hyperpolarization of the postsynaptic membrane. This hyperpolarization of the membrane is called a(n) _____.

inhibitory postsynaptic potential

Communication between neurons occurs via a process called _____.

synaptic transmission

Conscious recognition of the position of body parts with respect to one another as well as recognition of limb-movement rates is called .

kinesthesia

After release into the synaptic cleft, neurotransmitters bind to receptors on the target membrane, which produces a series of graded depolarizations in the dendrites and cell body. These graded depolarizations are known as _____.

excitatory postsynaptic potentials

Identify the ways in which excitatory postsynaptic potentials (EPSPs) can bring the postsynaptic neuron to threshold. (Check all that apply.)

Spatial summation
Temporal summation

Inhibitory postsynaptic potentials result in the development of a(n) _____.

more negative resting membrane potential

Kinesthesia is accomplished by extensive sensory devices in and around joints known as joint proprioceptors. These include _____.

free nerve endings, Golgi-type receptors, and Pacinian corpuscles

Match the types of joint proprioceptors with their descriptions
free nerve endigs
Golgi-type receptor
pacinian corpuscle

free nerve ending - These receptors are the most abundant and are stimulated strongly at the beginning of a movement; they adapt slightly at first, but then transmit a steady signal until the movement is complete.

Golgi-type receptor -These receptors are found in ligaments around joints and work by adapting slowly.

pacinian corpuscle - These receptors are found in the tissues around joints and adapt rapidly following the initiation of movement to help detect the rate of joint rotation.

Muscle spindles act as length detectors, and are important for achieving a high degree of control in movement. Identify the muscles that are likely to have the highest density of muscle spindles.

hand muscles

The muscle spindle is composed of several thin muscle cells called _____ fibers that are surrounded by a connective tissue sheath.

intrafusal

Identify the joint proprioceptor that adapts rapidly following the initiation of movement.

Pacinian corpuscles

Muscle spindles contain two types of sensory nerve endings called _____ endings.

primary and secondary

Muscle spindles are found in large numbers in most human locomotor muscles and act as _____.

length detectors

The knee-jerk reflex is often evaluated by the physician by tapping the patellar tendon with a rubber mallet. The blow by the mallet stretches the entire muscle and excites the primary nerve endings located in _____.

muscle spindles

The function of a muscle spindle is to assist in the _____.

regulation of movement and to maintain posture

Identify a true statement about the structure of muscle spindles.

muscle spindles run parallel to muscle fibers

When activated, Golgi tendon organs send information to the spinal cord via sensory neurons, which in turn excite _____.

inhibitory neurons

Match the types of nerve endings found in muscle spindles with their functions
Primary ending
Secondary ending

Primary ending - responds to dynamic changes of length
Secondary ending - This provides the central nervous system with continuous information concerning static muscle length

Muscle spindles are responsible for the observation that rapid stretching of skeletal muscles results in a reflex contraction. This reflex is called the _____.

myotatic response

In order to reduce the amount of force generated by a muscle after a vigorous contraction of the muscle group, the Golgi tendon organ (GTO) responds by _____.

instructing the spinal cord to inhibit motor neuron firing

Muscle spindles regulate movement and maintain posture by their ability to detect and cause the central nervous system to _____.

respond to changes in the length of skeletal muscle fibers

The information provided by the muscle chemoreceptors to the central nervous system is important in the control of _____.

cardiovascular and pulmonary responses to exercise

Golgi tendon organs continuously monitor the tension produced by muscle contraction and basically function as a(n) _____.

safety device

The somatic neuron that innervates skeletal muscle fibers is called a(n) _____.

motor neuron

The number of muscle fibers innervated by a single motor neuron is called the _____.

innervation ratio

One of the ways that the central nervous system can increase the force of muscular contraction is by increasing _____.

motor unit recruitment

The orderly and sequential recruitment of larger motor units is called the _____.

size principle

The physiological role of muscle chemoreceptors that respond to chemical changes within the muscle is to provide the central nervous system with information about the _____.

metabolic rate of muscular activity

The primary function of the vestibular apparatus is to _____.

maintain equilibrium and preserve a constant plane of head position

Each motor neuron and all the muscle fibers that it innervates is known as a(n) _____.

motor unit

For coordinated movement to occur, it is absolutely essential that the motor cortex receives input from _____.

subcortical structures

Identify a true statement about the innervation ratio.

it is low in muscle groups that require fine motor control

Which of the following is true of the cerebellum?

It lies behind the pons and medulla.

The progressive activation of more and more motor neurons is referred to as _____.

motor unit requitment

_____ is a series of complex neurons scattered throughout the brain stem which receives and integrates information from all regions of the CNS.

reticular formation

According to the size principle, the first motor units to fire when a muscle is initially activated are _____.

small in size

The spinal mechanism by which a voluntary movement is translated into appropriate muscle action is termed _____.

spinal tuning

Identify how the vestibular apparatus maintains balance.

The receptors contained within the vestibular apparatus are sensitive to any change in head position.

It is sensitive to sudden changes in the direction of body movement.

The simultaneous excitatory and inhibitory activity that occurs during the withdrawal reflex action is known as _____.

reciprocal inhibition

The portion of the cerebrum that is most concerned with voluntary movement is the _____.

motor cortex

The area of the brain that is the final executor of movement programs is the _____.

motor cortex

The primary role of the cerebellum is to aid in the control of movement _____.

in response to feedback from proprioceptors

The medulla, pons, and midbrain are the major structures of the _____.

brain stem

The interaction of the spinal cord neurons and higher brain centers results in the _____.

refinement of movement

The autonomic nervous system plays an important role in _____.

maintaining homeostasis

In the withdrawal reflex, the nerve pathway from the receptor to the central nervous system (CNS) and from the CNS along a motor pathway back to the effector organ is called a _____.

reflex arc

Match the parts of the autonomic nervous system with the actions they perform
Parasymphatetic division
Symphatetic division

Sympathetic division - slows down heart rate
Parasympathetic division - increases heart rate

In the control of voluntary movement, the initial drive to move occurs in the _____.

subcortical areas

Regular aerobic exercise promotes a cascade of brain growth factor signaling that _____.

enhances memory and learning

Identify the true statements about the brain stem

It is located inside the base of the skull just above the spinal cord.
It is responsible for many metabolic functions and cardiorespiratory control.

Identify the muscles that are innervated by the autonomic nervous system

Cardiac muscles

The autonomic nervous system can be separated both functionally and anatomically into two divisions. These are called the _____ divisions.

sympathetic and parasympathetic

T/F Exercise reduces several peripheral risk factors for cognitive decline, including inflammation, hypertension, and insulin resistance.

True