Lab 6- Electrodermal Activity (EDA) and Polygraph, Lab-7 Electromyography, Lab 8- Electrooculogram (EOG)

What are the divisions of the nervous system?

sensory division

efferent division

What is the sensory division?

sends information to the CNS

What is the efferent division?

takes information from the CNS

What makes up the central nervous system?

brain and spinal cord

What is the breakdown of efferent neurons?

autonomic neurons

somatic motor neurons

What makes up autonomic neurons?

sympathetic

parasympathetic

What do sympathetic and parasympathetic control?

• cardiac muscle

• smooth muscle

• exocrine glands/ cells

• some endocrine glands/ cells

• some adipose tissue

What do somatic motor neurons control?

skeletal muscles

What is the sensory neurons?

sensory receptors stimulate sensory neurons (afferents) to the central nervous system

What communicates with the digestive tract?

autonomic neurons with neurons of enteric nervous system

What is also known as the autonomic division?

autonomic nervous system

vegetative nervous system

visceral nervous system

What is the parasympathetic system?

“rest and digest”

quietly state after a meal

restore body function

parasympathetic neurons

What is the sympathetic system?

“flight or fight”

responses to strenuous physical activity in emergency or stressful situations

sympathetic neurons

What are the target cells for autonomic neurons?

• smooth muscle

• cardiac muscle

• exocrine and endocrine glands

• lymphoid tissue

• adipose tissue

What are visceral effectors?

• smooth muscle

• glands

• cardiac muscle

• adipocytes

What is the antagonistic control of the autonomic division?

most internal organs are under antagonistic control

one autonomic branch is excitatory, and the other branch is inhibitory

adrenergic receptors

What is electrodermal activity (EDA)?

Changes in the skin’s ability to conduct electricity (conductance).

What is human EDA range?

1-20 microsiemens

What branch is the electrodermal activity associated with?

sympathetic branch

What is the physical response for EDA?

changes in the affective state of a subject

What is EDA affected by?

affected by sweat gland activity and skin responses on the palms of the hands or soles of the feet

What is EDA in highly aroused (alert) state?

Sweat gland activity and the Electrodermal activity increase

What is EDA in relaxation state?

sympathetic activity is low

sweat gland activity and electrodermal activity decrease

What is EDA an index of?

sympathetic activity

What elicits changes in PNS?

changes in emotions

What are examples of sensory stimuli?

smell, taste, hear, see

What are examples of somatic stimuli?

pain, pressure, touch

What do changes in emotion lead to changes in?

changes on psychophysiological variables

What are examples of psychophysiological variables?

• heart rate

• respiratory rate

• blood pressure

• sweat

What is current (I)?

flow of electrical activity generated by our body

What is Resistance (R)?

direction of the current; opposition to the flow of electrical current in a circuit.

What does the direction of the current depend on?

electrical pressure or electromotive force (E)

difference in charges between two points

What does current flow obey?

Ohm’s law

I = E/R

I α E but, I α/R

I=Amp; R=ohms (Ω); E= Volts

What is the flow of painful stimulus to resistance and conductance?

stimulus painful → sympathetic branch → sweat glands → water and electrolytes → resistance low; conductance high

What is biofeedback?

conscious control over phsyiological processes

ie. heart rate, blood pressure

What does biofeedback activate?

It activates specific controls of the parasympathetic branch and decreases the activity of the sympathetic part of the autonomic nervous system

In stressful situations, what does biofeedback do?

increase heart rate, blood pressure, sweat, etc.

decrease biofeedback

What is skeletal muscle?

Skeletal muscle is a collection of muscle cells, or muscle fibers.

actin and myosin

What is the morphology of skeletal muscle fibers?

large, mutlinucleate cells that appear striped or striated under the microscope

What is a muscle fiber?

a long, cylindrical cell with many nuclei near the surface of the fiber.
Attached to Skeletal Muscle

What makes up muscles?

fiber covered by connective tissue

several fibers: fascicle (group of fibers together) covered by connective tissue

several fascicles covered by connective tissue

What is a contraction?

a process that enables us to

1. create force

2. move

3. resist a load

What is to create force?

muscle tension (requires ATP)

What does resist a load require?

requires ATP

What is relaxation?

release of tension created by contraction

What innervates skeletal muscle?

motor neurons

What are motor neurons?

Nerve cells that transmit signals from the spinal cord to muscles, enabling movement.

What is the main chemical messenger in muscle contraction?

Acetylcholine (initiate contraction of skeletal muscle fibers by binding to receptors at the neuromuscular junction) bind to cholinergic receptors → open sodium channels which changes membrane potential of muscle (positive ions produce electrical signals) → contraction

How does contraction happen cellularly?

receive action potential → sarcoplasmic reticulum liberates calcium → calcium is a signal that will bind to accessory protein associated with actin and myosin: troponin (and calcium) and tropomyosin → produce a contraction

What is a neuromuscular junction?

The synapse or connection point between a motor neuron and a skeletal muscle fiber, facilitating communication and muscle contraction.

What tissues are excitable?

nervous and muscle tissue

What does contraction force depend on?

depends on the types and numbers of motor neurons

What is a motor unit?

the basic unit of contraction in skeletal muscle (Group of muscle fibers and somatic motor neuron)

How can contraction be increased?

recruiting additional motor units

What is asynchronous recruitment?

Different motor units take turns maintained the tension (prevent fatigue)

What is the main function of asynchronous recruitment?

prevent fatigue

What is the association between fiber and and motor nerve?

The relationship between muscle fibers and their corresponding motor nerves is that each motor nerve innervates a group of muscle fibers, forming a motor unit that functions together to produce muscle contraction.

What are the possible physiological processes that cause fatigue?

1. accumulation

2. depletion

What is accumulation as possible physiological processes that cause fatigue?

hydrogen ion

lactate

What is depletion as possible physiological processes that cause fatigue?

glycogen

ATP

What is the most efficient surface of energy for ATP production?

Carbohydrates (glucose)

What is fatigue?

Reversible condition in which a muscle is no longer able to generate or sustain the expected power output.

What is electromyography?

The detection, amplification, and recording of changes in skin voltage produced by skeletal muscle

What is the recording obtained from the detection, amplification, and recording of changes in skin voltage produced by skeletal muscle?

electromyogram (EMG)

What are the two principal bioelectric activities that the EMG records?

1. Propagation of motor nerve impulses and their transmission at the neuromuscular junctions of a motor unit.

2. Propagation of the muscle impulses (excitation contraction coupling).

What are the electrical and mechanical events in our muscles?

The electrical events include the generation and propagation of action potentials in muscle fibers, while the mechanical events involve muscle contraction and relaxation as a response to these electrical signals.

muscle action potential

muscle fiber recruitment and contraction

What is a twitch?

a single contraction-relaxation cycle

What is a dynamometer?

records force, tension, or power

What is a dynagram?

a visual output/ record that illustrates the relationship between the force exerted by a muscle and the time during which it is applied.

signal goes up: muscle contract

signal goes down: relaxation of muscles

What does the electrical response on the EMG come from?

Electrical response on the EMG come from the motor neuron action potential and the muscle fiber action potential

What are uses of electromyography in the health care field?

Evaluation of:

• Muscular disorders

• Motor neuron function

• Muscular function after surgery (hand or arms)

What is a muscular disorder?

Disorders: Muscular dystrophy

What is motor neuron function uses of EMG in the health care field?

Problems associated with the connection between the nerve and the muscle: Myasthenia gravis

Movement of each eyeball in its orbit is caused by the individual
contractions of

extrinsic eye muscles (6-voluntary)

skeletal muscles which allow to move the eye ball; voluntary

What are the extrinsic eye muscles?

Superior rectus

inferior rectus,

lateral rectus

medial rectus,

superior oblique

interior oblique

What is the main movement of the eye accredited to (which nerve)?

oculomotor nerve (cranial nerve III)

What is the movement of each eyeball controlled by?

CN III, IV, VI

What is CN III?

oculomotor

What is CN IV?

trochlear (SO)

What is CN VI?

abducens (LR)

What muscles allow to move laterally?

lateral rectus

What muscles allow to move upward?

superior rectus

What muscles allow to move down and laterally?

superior oblique

What muscles allow to move medially?

medial rectus

What muscles allow to move up and laterally?

inferior oblique

What muscles allow to move downward?

inferior rectus

How many cardinal directions of gaze?

nine cardinal directions of gaze

How many muscles contract to move eyes (and difference between right and left eye)?

two muscles (different in left and right eye)

combination of six muscles to move eyes

not using the same muscles in both eyes

What muscle must be accompanied in central gaze?

do not contract all of the muscles, can see the horizon

What does the movement of eyes involve?

extraocular muscles, cranial nerves, and motor control centers of the brain

What is visual fixation?

Muscular control of the eye to keep the image on the fovea
(regarding if the object is moving or not)

What are the two mechanisms used to fixate on objects in the visual field?

voluntary fixation

involuntary fixation

What is voluntary fixation?

Conscious effort to direct the
gaze to a selected object and
“lock on” to i

What is involuntary fixation?

Subconscious mechanisms that help
to keep a selected object in the field
of view (after lock on to it).

What does visual fixation does not involve?

It does not involve movements of the head

What are saccades?

Saccades are quick, jerky, voluntary
movements of the eyes.

The human eye is an electrical ____

dipole

Negative dipole of the human eye?

retinal pigment epithelium

posterior of the human eye.

Positive dipole of the eye?

cornea

anterior of the human eye.

What is corneal-retinal potential (CRP)?

The potential between the front and the back of the eyeball

differences in charge