Skin Anatomy, Neurological Testing 1, and General Sensory Pathways
(Lab Manual pg. 73)
Lab Preparation
· Review the anatomy of cutaneous tissue.
· Review your lab atlas and the list of video links associated with this lab.
· Follow your lab manual and complete the activities therein as it will guide your investigation. The lab manual is also the document that will inform the Lab Tests.
Lab Objectives
· Identify skin, hypodermis regions on models and slides.
· State the common names and functions of cutaneous glands.
· State the functions and locations of cutaneous sensory receptors.
· Identify the cutaneous general sensory receptors.
Having studied the CNS and the peripheral nerves directly associated with both the
ain and spinal cord we now turn our attention to how the body senses stimulation. Sensory reception can be classified according to stimulus type, origin of stimulus, and receptor structure. This lab deals with general sensory structures and their reflex pathways while the following two lab activities focus on special sensory structures and their reflex pathways.
In order to address any reflex pathway we must first address the nature of the stimulus that the body is responding to. Towards that end we revisit the Integumentary system, only this time we focus on specific mechanoreceptors, presence or absence of encapsulation, and location within the dermis. You will then explore the reflexive responses of four spinal reflex arcs. The last part of this lab addresses how the body is able to adapt to constant stimulus or resist adaptation dependent upon the nature of the stimulus.
Review of the Integumentary System
Video Link to The Integumentary System
Video Link to The Science of Skin
Cutaneous Accessory Structures
Video Link to The Integumentary System Part II
Video Link to Composite Skin Model
No need to focus on this much detail regarding secretory products but this is a good description of the names and locations of the sebaceous and sudoriferous glands.
Video Link to Meissner corpuscle, Pacinian corpuscle, Ruffini ending , Merkel disc
This video discusses all the general sensory receptors you need to be familiar with. Focus on function and location. The details regarding adaptation and receptor field pertain to the two-point discrimination test and various tests regarding adaptation we will look at later in this activity. Ignore the discussion regarding A and B axons
Video Link to Touch Receptors
Blood Vessels of the Integumentary System
Capillaries
Arterioles & Venules
Arteries & Veins
Overview of Monosynaptic and Polysynaptic Reflex Pathways
Video Link to Monosynaptic and Polysynaptic Reflexes
NOTE: For the following reflexes focus on the stimulus and reflexive response. I will not ask about which specific nerve numbers are participating in the reflex arc. The most detail I would ask about is whether it is a spinal or cranial reflex. Once you go through these examples that distinction should be clear.
Patellar (Knee-jerk) Reflex
Video Link to Knee-jerk Reflex
Video Link to Normal Patellar Reflex Exam
Video Link to Patellar Reflex Test
Achilles Tendon (Ankle-jerk) Reflex
Video Link to Achilles Heel Tendon Reflex Test
Withdrawal Flexor Reflex with Crossed-Extensor Component
Video Link to Withdrawal/Flexor Reflex
Video Link to Crossed-Extensor Description
Plantar Flexion Reflex (Babinski sign)
Video Link to The Plantar Flexion Reflex
Cranial Nerve Reflexes
The following video describes the procedures involved in assessing the 12 pairs of cranial nerves.
Video Link to Cranial Nerve Examination
NOTE: The cranial reflexes WILL NOT BE TESTED ON. I have included this video just for personal interest.
Two-Point Discrimination Test (Can be tested at home)
Video Link to Two-Point Discrimination Test
Overview of Sensory Adaptation
Video Link to Sensory Adaptation
Video Link to Sensory Adaptation 2
Adaptation to Temperature
Video Link to Fool Your Senses
Radiating Pain
Video Link to Ulnar Neuropathy at Elbow
This video goes into much more detail than is required but the first half does a good job of describing the path of the ulnar nerve and the regions of the hand that it collects sensory information from.
Video Link to Cubital Tunnel Surgery
The first three minutes of this video offer additional explanation of the path of the ulnar nerve and the experience of tingling and numbness felt after striking your “funny bone”. There is no need to focus on the latter discussion regarding surgery techniques.
Nerve Physiology Lab Activity (Complete this as you watch the Dissection Video)
Part I
Consider the normal behavioral responses of the frog as described in the chart below and seen in the video. Indicate in the chart below which surgical procedure you hypothesize will eliminate each reflexive behavior. Justify your hypothesis in the final column by identifying the CNS and/or PNS structure responsible for the normal behavior.
Normal Frog
Frog w/o cere
um & diencephalon
Frog w/o cere
um, diencephalon, &
ain stem
Frog w/o cere
um, diencephalon,
ain stem, & spinal cord
Identify the
ain region, spinal cord, or cranial nerve that controls the normal behavior. Identify only ONE component unless otherwise instructed.
Corneal reflex
Eye blinks when cornea is touched
Swimming
Coordinated swimming movements using hind legs
?
?
?
Hint: ID one
ain division
?
Posture
Uses forelegs to maintain upright posture
?
?
?
Hint: ID one
ain division
?
Breathing
Normal bpm
?
?
?
Hint: ID one
ain division
?
Tongue position
Tongue lies flat on floor of mouth
?
?
?
Hint: ID one cranial nerve
?
Righting reflex
Quickly rights itself when placed upside down
?
?
?
Hint: ID one
ain division & one cranial nerve
?
Acid reflex
Attempts to wipe acid away with leg swipe
?
?
?
?
Withdrawal reflex
Quickly flexes leg away from stimulus
?
?
?
?
Pupillary Reflex Predictions
How will the pupils react when exposed to acetylcholine?
Type answer here.
How will the pupils react when exposed to epinephrine?
Type answer here.
Part IIA
While watching the video, mark the columns where the behavior was eliminated. After the video, fill out the additional columns indicating if this matched your hypothesis. Co
ect your explanation if necessary.
Normal Frog
Frog w/o cere
um & diencephalon
Frog w/o cere
um, diencephalon, &
ain stem
Frog w/o cere
um, diencephalon,
ain stem, & spinal cord
Normal Frog
Write your explanation, modify if it was inco
ect. Identify the
ain region, spinal cord, or cranial nerve that controls the normal behavior.
Swimming
Coordinated swimming movements using hind legs
?
?
?
?
Hint: ID one
ain division
?
Posture
Uses forelegs to maintain upright posture
?
?
?
?
Hint: ID one
ain division
?
Breathing
Normal bpm
?
?
?
?
Hint: ID one
ain division
?
Tongue position
Tongue lies flat on floor of mouth
?
?
?
?
Hint: ID one cranial nerve
?
Righting reflex
Quickly rights itself when placed upside down
?
?
?
?
Hint: ID one
ain division & one cranial nerve
?
Acid reflex
Attempts to wipe acid away with leg swipe
?
?
?
?
?
Withdrawal reflex
Quickly flexes leg away from stimulus
?
?
?
?
?
Part IIB
Organ and Neuromuscular Activity. Write in full sentences with co
ect grammar & spelling.
Type answer here.
What organ was removed from the frog?
Type answer here.
What was observed about this organ?
Type answer here.
Explain the reason behind this observation. Also, include the role of the CNS in an intact frog on this organ in your explanation.
Type answer here.
Sciatic Roots
What happened when the sciatic roots were cut?
Type answer here.
Which of the three kinds of gated ion channels were stimulated by this?
Type answer here.
What happened when the sciatic roots were sprinkled with salt?
Type answer here.
Which of the three kinds of gated ion channels were stimulated when the sciatic roots were sprinkled with salt?
Type answer here.
Benzocaine Gel
Which nerve was the focus of this experiment?
Type answer here.
What was observed upon electrical stimulation before the application of the gel?
Type answer here.
What was observed upon electrical stimulation after the application of the gel?
Type answer here.
Pupillary Reflex
How did the pupils react when exposed to acetylcholine?
Type answer here.
How did the pupils react when exposed to epinephrine?
Type answer here.
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