Labs 1-4

Question 1

When do you use an XY scatter graph?

Answer 1

When both sets of data are numerical in nature and continous

Question 2

Which axes do the dependent and independent go on for an XY scatter graph?

Answer 2

Y: dependent variable
X: Independent variable

Question 3

Compare vasodilation and vasoconstriction.

Answer 3

Vasodilation: increased blood flow, size, diameter in arteries

Vasoconstriction: decreased blood flow, size, diameter in arteries
Vasoconstriction is the narrowing (constriction) of blood vessels by small muscles in their walls

Question 4

What occurs when an animal encounters a stimulus?

Answer 4

• stimulus is detected by one or more sensory receptors
• sensory info is sent to the CNS for processing

Question 5

Define nervous system integration.

Answer 5

The generation of a motor output based on the sum of sensory inputs

Question 6

How is most of the integration within a nervous system done?

Answer 6

by way of reflex arcs

Question 7

Define reaction time.

Answer 7

The time from the start of a signal to the response

Question 8

How does the sensory system stimulated affect reaction time?

Answer 8

(1) Differences in afferent conduction time between sensory systems
(2) some sensory systems can change instantly while others change more slowly
(3) certain sensory systems are more sensitive

Question 9

Define visuo-motor learning.

Answer 9

The process of increasing the accuracy, speed, and coordination of tasks involving hand-eye coordination the more often we perform them

Question 10

How do you find the standard error of the mean?

Answer 10

Standard Deviation/ SQRT (N)

Question 11

What does the standard error of the mean quantify?

Answer 11

How much the reaction times vary amongst the students; helps answer how sure we are that the data is within the normal range

Question 12

How does the alteration of blood flow caused by vasoconstriction/vasodilation effect the pulse amplitude?

Answer 12

Contraction of cardiac muscle cells in the ventricle of the heart causes the ventricles to reduce their volume and force blood into the major arteries of the circulatory system. Each pulse of blood ejected from the ventricle exerts a physical force on the walls of the blood vessels that is generally measured as blood pressure.
Changes in local blood flow due to vasoconstriction or vasodilation results in a slight change in the volume of local tissue, and this change in volume can be detected by a plethysmograph.
Aka the differences in blood flow for each pulse

Question 13

How does vasoconstriction and vasodilation relate to homeostasis?
Hint: think of lab #1 with cooling and rewarming

Answer 13

Within the dermis of the skin there are specialized sensory receptors that detect skin temperature. Once activated, these peripheral thermoreceptors send neuronal signals to the hypothalamus of the brain. This information is then integrated as part of a larger homeostatic mechanism that causes various physiological changes, including alteration of local blood flow to skin and other organs.
This is achieved by vasoconstriction or vasodilation

Question 14

How do the visual and auditory pathways compare? Why is the auditory pathway faster?

• Fenton et. al., 2022, p. 1147 & 1235
• Russell et al., 2019, p. 1220 & 1223

Answer 14

Information about the acoustical waves in the air are picked up by specialized mechanoreceptors called hair cells, whereas rods and cones in the retina detect information about light waves.
The vertebrate brain is then responsible for interpreting information from the auditory pathway as sound, the visual pathway as an image, and generating appropriate motor responses.

The auditory pathway starts at the cochlear nucleus, then the superior olivary complex, then the inferior colliculus, and finally the medial geniculate nucleus. The information is decoded and integrated by each relay nucleus in the pathway and finally projected to the auditory cortex.

The visual pathway consists of the retina, optic nerves, optic chiasm, optic tracts, lateral geniculate bodies, optic radiations, and visual cortex. The pathway is, effectively, part of the central nervous system because the retinae have their embryological origins in extensions of the diencephalon.

Since the auditory stimulus reaches the cortex faster than the visual stimulus; the auditory reaction time is faster than the visual reaction time.

Question 15

What is neural integration?

Answer 15

When the central nervous system (CNS) collects sensory (afferent) information from sensory neurons and receptors, and compares that to learned or innate information stored within the interneurons of the CNS, then sending appropriate motor (efferent) signals to peripheral cells, tissues, and organs.

Question 16

Describe prismatic adaptation. Explain the underlying significance in terms of nervous system function.

Answer 16

A specific form of sensorimotar learning:
the motor system adapts to new visuospatial coordinates imposed by prisms that displace the visual field horizontally.
Some potential clinical applications include: treatment for spatial neglect

Question 17

What is visual-motor learning?

Answer 17

VISUAL MOTOR integration is a complex skill set which encompasses many underlying skills such as visual perception, motor control, and eye-hand coordination. Simply stated, it refers to the ability to translate a visual image, or a visual plan, into an accurate motor action.

Question 18

How does visual-motor learning influence our lives?

Answer 18

Visual motor integration can be defined as the coordination of visual perception and fine motor control.

Visual motor skills are integral to efficient and coordinated movement which allows your child to successfully engage in daily occupations. Visual motor integration is important for handwriting, playing, feeding, and much more.

Question 19

Describe sensory receptor adaptation.
Hint: Lab 3, later on in the experiment the action potentials are firing further apart in time. Why?

Answer 19

A decline of sensory receptor firing rate with prolonged duration

Question 20

What is the purpose of receptor adaptation?

Answer 20

Allows information that might not be as pertinent to be filtered out.

Question 21

What are the three types of receptor reponses in the cockroach leg?

Answer 21

(1) phasic
(2) Tonic
(3) Phasotonic

Question 22

What is a motor unit? What is motor unit recruitment?

Answer 22

The combination of an individual motor neuron and all of the muscle fibers that it innervates is called a motor unit. The number of fibers innervated by a motor unit is called its innervation ratio.

Motor unit recruitment is the process by which different motor units are activated to produce a given level and type of muscle contraction

Question 23

What is motor-unit recruitment? Why is it useful?

Answer 23

It allows for different levels of muscle activity and the determination of the level of force

Question 24

What is tetanus and how is it achieved?

Answer 24

When maximum physical force is achieved

Question 25

Explain the differences between dominant and non-dominant hands when measuring EMG during grip force.

Answer 25

Strength, manual control,

Question 26

What is the function of reflexes?

Answer 26

Reflexes are kind of like safety features for survival that allow us to move in response to something in the environment. Reflexes can act to protect you in many ways, including removing your hand from a hot or sharp object, or ducking when a loud and sudden sound occurs. These fast actions are reflex responses!

Question 27

Compare reflexes and reactions.

Answer 27

Reactions are voluntary responses whereas reflexes are involuntary or unintentional (and not subject to conscious control in most cases). Each type of response is initiated by a sensory stimulus that may be visual, audible, tactile, olfactory, or gustatory in nature.

Question 28

In lab 4 experiment 2 what were you trying to find from the data?

Answer 28

The mean reflex time, which is needed to determine the conduction velocity

Question 29

What is total path length?

Answer 29

“There and back”
Up from the knee to CNS and then back to knee
that is why the measurement was doubled

Question 30

What is synaptic transmission time?

Answer 30

0.5 milliseconds: time associated with acetylcholine being released at the neuromuscular junction

Question 31

What is conduction velocity?

Answer 31

How quickly the action potential information is spread along the nerve

Question 32

Define mechanoreceptors

Answer 32

Specialized sensory nerve cells that respond to touch, pressure, sound, movement, and stretch; can detect both external and internal stimuli

Question 33

Define proprioreceptors.

Answer 33

Internal mechanoreceptors that function to tell us information about muscle position, contraction, movement, and place in space

Question 34

What occurs when a mechanical force stimulates a mechanoreceptor?

Answer 34

An action potential is triggered in the mechanoreceptor neuron that travels to higher ganglion for processing

Question 35

Define setae

Answer 35

short hair mechanoreceptor

Question 36

Define hair plates

Answer 36

hair cluster mechanoreceptor

Question 37

Define campaniform sensilla

Answer 37

dome-like structures which are distorted with the movements of the spines that protrude from surface of sensilla or with leg movements

Question 38

Define chordotonal organs

Answer 38

structures under cuticle which change length when joint that organ spans is extended or flexed

Question 39

Define stretch receptors

Answer 39

Used to detect the position of the limb as the subject moves. As the limb is moved from a neutral position, sensory neurons increase rate at which they generate AP’s

Question 40

Define firing rate

Answer 40

Action potentials / second

Question 41

How do a vast majority of sensory receptors in animals encode information about stimulus intensity?

Answer 41

Sensory receptors detect some variable of the environment and relay information about that variable to the CNS via action potentials in afferent (sensory) neurons. The firing rate changes to relay information about stimulus intensity.

Question 42

Provide the two major sources of electrical noise.

Answer 42

Pickup and ground loops

Question 43

How do we reduce electrical noise? Define the device.

Answer 43

By using a Faraday Cage: a grounded screened enclosure that sits around the preparation and electrodes and separates the source of the radiation from the electrodes

Question 44

Describe the structure of a cockroach leg.

Answer 44

Metathoracic legs: hind legs
Coxa: upper portion of leg
Trochanter: acts like a knee, allows bending of leg
Femur: resembles thigh
Tibia: resembles shin
Tarus: acts like ankle and foot

Question 45

What occurs when a cockroach leg moves?

Answer 45

Flexion and extension of the tibia causes changes in the length of the chordotonal organs

Question 46

What does the recorded AP amplitude depend on?

Answer 46

The diameter of the neuron and the distance of the electrodes from the neuron

Question 47

Define phasic

Answer 47

Rapidly adapting responses typically associated with changes in intensity of a stimulus

Question 48

Define tonic

Answer 48

Slowly adapting responses typically associated with a prolonged stimulus

Question 49

Describe the path of blood flow during a complete circuit of blood flow from the left ventricle of the human heart to the finger-tip and then the path back to the left ventricle, naming the major vessels and heart structures encountered along this circuit.
Hint: Taylor et. al., 2014

Answer 49

The heart:
(1) right atrium through superior & inferior vena cava
(2) right ventricle
(3) left & right pulmonary arteries
(4) oxygenated at lungs
(5) pulmonary veins to left antrium
(6) left ventricle
(7) out aorta and aortic arch

Blood flow to right hand:
(8) brachiocephalic trunk
(9) subclavian artery, axillery artery, brachial artery, radial/ulnar artery

Back to heart
(10) blood vessels that take oxygen-poor blood back to the heart
- Veins become larger and larger as they get closer to the heart.
- The superior vena cava is the large vein that brings blood from the head and arms to the heart

Question 50

What is a plethysmograph and what does it measure?

Answer 50

Device that measures pulse amplitude through blood volume of tissue

Question 51

Define the following terms:
(1) homeostasis
(2) negative feedback
(3) set-point
(4) hypotension
(5) hypertension

Answer 51

(1) Homeostasis: the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits

(2) Negative feedback: Negative feedback occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances. (example: blood sugar regulation)

(3) Set-point: the physiological value around which the normal range fluctuates. A normal range is the restricted set of values that is optimally healthful and stable.

(4) Hypotension: Low blood pressure occurs when blood flows through your blood vessels at lower than normal pressures. The medical term for low blood pressure

(5) Hypertension: abnormally high blood pressure in the arteries, which are the blood vessels that carry blood from the heart to the rest of the body.

Question 52

Explain how central blood pressure relates to peripheral blood flow and visa versa.

Answer 52

Peripheral blood flow comprises the systemic circulation, which supplies blood to all parts of the body except the lungs, and the pulmonary circulation, which supplies blood to the lungs.
Central blood pressure is the pressure in the aorta, the large artery that sends blood from the heart throughout the body.

The more blood that is flowing through the aorta artery, the greater peripheral blood flow throughout the body.

Question 53

Compare the effect of gravity on a shark with that in a giraffe.

Question 54

How did gravity and temperature effect peripheral blood flow in lab 1?

Answer 54

• Lowered average pulse amplitude when limp was elevated
• slightly greater when limp lowered
• cooling lowered average pulse amplitude
• rewarming slightly raised above resting

Question 55

Define reflex arc.

Answer 55

A reflex arc defines the pathway by which a reflex travels—from the stimulus to sensory neuron to motor neuron to reflex muscle movement.

Question 56

Define interneuron.

Answer 56

a neuron which transmits impulses between other neurons, especially as part of a reflex arc.

Question 57

What is sensimotor adaptation? Why is it important?

Answer 57

The ability of the CNS to engage in learning and to modify output based on previous experience.
This is key to learning and the basis by which the behaviour of animals can be modifed over time and new tasks learned.

Question 58

What is a sensory receptor?

Answer 58

A specialized cell that will respond to the environment variable by releasing a neurotransmitter at a synapse with the dendrites of an afferent sensory neuron. The afferent sensory neuron will then respond to the action potential of the membrane (if threshold) and relay information to other parts of the nervous system.

Question 59

Define sensory adaptation and describe its importance to animal survival.

Answer 59

If a stimulus is prolonged in duration, the sensory neuron firing frequency will decline over time. Sensory organs can differ in the speed of sensory adaptation.

Question 60

Describe the anatomy of the cockroach chordotonal organ.

Answer 60

Chorodotonal organs contain a mix of phasic and tonic sensory neurons.
The neuronal axons associated with the chordotonal organ in the cockroach tibia travel through a large sensory nerve that passes into the cockroach’s femur before synapsing on interneurons in the segmental ganglion of the ventral nerve cord.

Question 61

Explain the role of firing frequency coding in neural integration in animals (generally).

Answer 61

As the leg is moved from a neutral position, the chordotonal organ is stretched and the sensory neurons increases the rate at which APs are generated. This change in firing frequency (APs/second) is used within the CNS to monitor leg position.

A high firing frequency is interpreted by the CNS as a large leg movement, whereas a low firing frequency is interpreted as a small leg movement.

Action potential cannot be maintained and this is why we see adaptation.

Question 62

Cockroaches and other insects have a number of different kinds of mechanoreceptors in their legs. These include:

Answer 62

(1) short hairs called setae
(2) clusters of thread-like structures called hair plates, which bend when ajoining surfaces of the cuticle contact each other in movement
(3) dome-like structures called campaniform sensilla, which are distorted with the movements of the leg
(4) structures under the cuticle called chordotonal organs, which change in length when the joint that the organ spans is extended or flexed

Question 63

What are the major types of stretch receptors found in vertebrate muscle and tendons, and what is their role in neural integration in these animals?

Answer 63

The major types of stretch receptors in vertebrates are muscle spindles and Golgi tendon organs.
These stretch receptors contribute to neural integration in these animals by sending sensory information to the CNS, which then modulates motor output.

Question 64

Why is sensory adaptation important in animals? Describe an experiment where you could demonstrate sensory adaptation in your own body.

Answer 64

Sensory adaption is important in animals because it helps the brain prioritize important stimuli along with reducing sensitivity to constant stimuli.
This helps conserve energy and avoid overloading the brain with unnecessary information.
An experiment that could be done to demonstrate sensory adaption in one’s own body is to place your hand in warm water for a few minutes and then immediately place it in cold water. At first, the cold water will feel very cold, but after a few moments, it will start to feel warmer as your brain adjusts to the new stimulus

Question 65

Firing frequency coding is an important mechanism used by sensory neurons to send information to the CNS about the intensity of a stimulus. What is some other ways that information about the stimulus can be encoded for the purposes of neural integration?

Answer 65

Other ways a stimulus can be encoded for the purpose of neural integration include:

(1) Spatial coding: refers to the specific location of a stimulus
(2) Temporal coding: refers to the timing of a stimulus
(3) Rate coding: refers to the frequency of action potentials generated by a sensory neuron, which can indicate the intensity of a stimulus
(4) Pattern coding: refers to the specific pattern of stimulation; such as the order in which different sensory neurons fire
(5) Amplitude coding: refers to the size of the action potentials generated by a sensory neuron; can indicate the strength of a stimulus
(6) Modulation coding: refers to the changes in frequency or pattern of firing in response to a stimulus

Question 66

What is a tendon, muscle bundle, muscle fiber, and neuromuscular junction (aka motor end plate)?

Answer 66

Tendon: used to attach muscles to bones and the coordinated contraction

Muscle bundle:

Muscle fibre:

Neuromuscular junction (motor end plate): specialized synapse releases acetylcholine to stimulate muscle contraction

Question 67

Compare the cellular physiology of a muscle twitch and tetanus.

Answer 67

A muscle twitch has a latent period, a contraction phase, and a relaxation phase. A graded muscle response allows variation in muscle tension. Summation occurs as successive stimuli are added together to produce a stronger muscle contraction. Tetanus is the fusion of contractions to produce a continuous contraction.

tetanus: When the frequency of muscle contraction is such that the maximal force is tension is generated without any relaxation of the muscle. summation: The occurrence of additional twitch contractions before the previous twitch has completely relaxed.

Question 68

Compare extensor and flexor muscles.

Answer 68

The muscles that decrease the angle between bones are called flexor muscles.

The muscles that increase the angles between bones are called extensor muscles.

Question 69

Describe a spinal reflex arc and the role of that stretch receptors (muscle spindles and Golgi tendon organs) have in coordinating limb movement.

Answer 69

Spinal reflex arcs are involuntary reflexes that have important roles in coordinating overall body position, posture, and locomotory patterns. The coordinated contraction and relaxation of antagonistic muscle groups are responsible for changes in limb position.

Question 70

What is electromyogram (EMG)?

Answer 70

The skeletal muscle recording

Question 71

Explain how nerves send electrical signals to muscles to cause a response, and the physiological basis for motor unit recruitment.

Answer 71

Skeletal muscle is an excitable tissue in that an action potential (AP) is generated along the plasma membrane of muscle cells.
- skeletal muscle AP controlled by motor neurons originating from the CNS
- motor neurons release a neurotransmitter (acetylcholine) at a specialized synapse called a neuromuscular junction (motor endplate).
- stimulate muscle cell contraction

Question 72

What is the functional significance of conduction velocity?

Answer 72

Nerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve. This test is done along with electromyography (EMG) to assess the muscles for abnormalities. The nerve conduction velocity test is performed to evaluate nerve function. It tests the speed impulses travel through a nerve.

Question 73

Describe the sliding filament model of skeletal muscle contraction.

Answer 73

The sliding filament model of contraction suggests that muscle contraction occurs due to the sliding of actin over myosin in the sarcomere. The neural stimulus causes the myosin to attach to its binding sites on actin allowing sliding to happen.

Question 74

Compare spatial and temporal summation and explain their role in muscle contraction.

Answer 74

spatial summation is the ability to integrate painful input from large areas while temporal summation refers to the ability of integrating repetitive nociceptive stimuli.