answer

watching

views

9 Apr 2018

When the right sternomastoid muscle is stimulated to contract by its alpha motor neuron:

the pectoral girdle on the right side would be pulled anteriorly as a direct result.

the left sternomastoid would have to be relaxed since the right and left sternomastoids oppose each other.

pressure or tension would be placed on the mandible as a direct result.

pressure or tension would be placed on part of the right temporal bone as a direct result.

answer

watching

113

views

For unlimited access to Homework Help, a Homework+ subscription is required.

You have 0 free answers left.
Get unlimited access to 3.8 million step-by-step answers.

Get unlimited access

Already have an account? Log in

Nestor RutherfordLv2

11 Apr 2018

Unlock all answers

Get 1 free homework help answer.

Already have an account? Log in

Related questions

Reflex Lab Procedures for Reflex Lab In this lab we will test muscle stretch reflexes and cutaneous reflexes. A partner is needed to be the subject for this lab. Purpose: To test and observe normal muscle stretch and cutaneous reflexes. Equipment: Reflex hammer, Background: In the most narrow sense, a reflex is an involuntary, unpremeditated response by the body to an external stimulus. Reflexes allow reaction to a stimulus more quickly than would be possible if conscious thought were involved. A reflex can be described as a stimulus-response cycle. Most reflexes involve the brainstem or the spinal cord and do not require interaction from higher brain centers. The muscle stretch reflexes are the simplest reflexes. They involve the sensory neuron synapsing directly upon the motor neuron. They are sometimes called monosynaptic reflexes. They are also called spinal reflexes because the reflexive action does not require input from the brain. The other reflexes we will be testing in this lab are the cutaneous reflexes. They are also called superficial reflexes because the receptors are in the superficial areas of the body. They are more complex and require the message to go up the spinal cord to the brain and then back down to elicit the response. These can be used to test for CNS injury. There are five components to a reflex; these components together are called the reflex arc. The components are as follows: sensory receptor â receives the stimulus and generates an impulse (is usually a nerve ending) afferent pathway â a neuron that carries the impulse from the receptor to a central integrating center integrating center âthis is where the afferent component connects to the efferent component- this is in the CNS. One or more synapses must occur here. Interneurons are not involved in stretch reflexes but are always found in all other types of reflexes. efferent pathway - a neuron that carries the impulse from the integrating center to an effector. effector -receives the impulse and responds. The effector may by skeletal muscle, smooth muscle, or glands.

Part I. Stretch reflexes.

First do muscle stretch reflexes which are also called deep tendon reflexes.

It is important the subject relax the muscle being tested. Tell the subject to let the muscle go limp.

Rate each response according to the following scale:

+4 very brisk, hyperactive, large movement at joint.

+3 brisker than average, medium movement at joint

+2 average, small movement at joint

+1 somewhat diminished, very small or no movement at joint

0 no response

A. Patellar (also called the knee jerk reflex) â activation of femoral nerve. The receptor is located in the quadriceps muscle, the effector is the quadriceps muscle. The nerve ending is responding to the stretch of the muscle caused by striking the tendon.

1. A subject is allowed to sit comfortably on a table with knees dangling over the edge.

2. Using a reflex hammer (or substitute as described above) strike the patellar tendon just below the kneecap.

3. Observe the action caused by the reflex.

4. Record your results using the graded scale above.

B. Biceps Reflex â activation of the musculocutaneous nerve

1. Rest subjectâs left forearm along your left forearm.

2. Subjectâs hand should rest in or near the bend of your elbow.

3. Press your left thumb on the subjectâs biceps tendon, apply a little pressure.

4. Strike your thumb with the reflex hammer, this will transfer the pressure to the biceps tendon.

5. Watch carefully for twitching of the biceps muscle. Usually, the forearm will not move.

6. Record your results using the graded scale above.

C. Triceps reflex â activation of the radial nerve.

This is a difficult reflex to observe, but give it a try.

1. The subject should have the arm relaxed and elbow bent.

2. Support the entire weight of the arm with your left hand.

3. Strike the triceps tendons, just above the elbow.

4. Watch carefully for twitching of the biceps muscle.

5. Record your results using the graded scale above.

Both B and C show up best on someone who doesnât have a lot of subcutaneous fat and who has good muscle definition.

D. Achilles reflex (also called ankle-jerk reflex) â activation of the poplitealnerve. The principle is similar to the knee-jerk reflex. Here the stretch receptors are located in the gastrocnemius muscle.

1. Have the subject take her/his shoes and socks off, exposing the Achilles tendon on the back of the ankle.

2. Strike the Achilles with the reflex hammer (or substitute) and observe the extension of the foot downward.

3. Record the results using the graded scale above.

Part II. Cutaneous reflexes

A. Plantar reflex

This reflex differs from the four muscle stretch reflexes. In this reflex, receptors are stimulated in the sole of the foot (cutaneous receptors). The reflex pathway travels up the leg to the integrating center. While in the integrating center, the reflex travels up the spinal cord through the pyramidal tracts, which are nerve pathways between the spinal cord and brain.

1. The subject needs to lie on his or her back, with shoes and socks off.

2. Using the end of the handle of the reflex hammer, trace a path along the lateral side from heel to the little toe to the big toe.

3. Observe for the flexion (toe curling) which is recorded as a normal plantar reflex.

4. If the toes curl, this is called a Negative Babinski response and is normal. If the toes flare, then an abnormal response is recorded and is called a Positive Babinski response and indicates CNS damage.

5. Record the results.

B. Ciliospinal reflex â This reflexive pathway is from the skin to the thoracic spinal cord, through the sympathetic trunk, then to the dilator pupillae muscle of the eye. This is another test of the CNS.

1. Pinch the back of the subjectâs neck,

2. Watch pupils for a response.

3. A normal response is dilation of the pupil.

4. Record your results.

To investigate Neilâs symptoms further, doctors referred him to a neurologist, Dr. Bonasera, that specialized in motor disorders. Dr. Bonasera noted that Neil exhibited diminished right dorsalis pedis and posterior tibial pulses. His cognitive tests were normal. Tests of the cranial nerves were normal, with the exception of occasional slurred speech. His motor tests revealed generally slowed movements. Neil was experiencing pain and stiffness in the shoulder joints, which could explain his restricted range motion. Dr. Bonasera tested the motor strength of his finger extensors (4+/5), hip flexors (4/5), and various muscle groups in his arms and legs (5/5). There were tests for dysmetria (i.e., lack of coordination) and dexterity, which were normal yet slowed. Neil did have difficulty lifting his legs for some of the examinations, and he walked with a shuffling gate, often keeping both feet close together for a narrow base of support. He took very small steps and often stooped over while walking. When placing one foot in front of the other in a tandem walking stance, he would fall to either side and was unable to regain his balance. Sensory examination was normal, deep tendon reflexes were normal, and the Babinski sign was absent bilaterally. There were no Parkinsons-like symptoms, increased motor tone, or muscle fasciculations observed in testing.

Just one day later, another neurologist noted brisk reflexes and bilateral Babinski signs. Doctors performed magnetic resonance imaging (MRI) of the brain to reveal an infarct in the right caudate nucleus and an infarct in the right cerebellum. Doctors prescribed intense physical therapy. Neil saw some improvements for articulation, but he continued to struggle with the speed of speech and began to experience weakness of the tongue on his left side. CT angiograms revealed an aneurysm of the infrarenal aorta extending into the right common iliac artery. A spinal MRI revealed degenerative disease of the cervical spine (C4-C5) with a mild central canal stenosis. No such degeneration was present in the thoracic or lumbar spine. However, Neil did have mild impingement of the right L3-L5 nerve roots. A lumbar puncture revealed normal CSF pressures, cell counts, and composition. Neil continued physical therapy and experienced significant improvements in speech, walking, and balance. He also commented that his muscle soreness and fatigue had improved.

Neil continued his physical therapy while recovering at home. However, his symptoms worsened over the following weeks. Neil grew progressively weaker, occasionally falling. He required assistance for walking, and he was experiencing some numbness in both hands. He was admitted to a hospital, where he underwent a neurological examination. Cognitive and cranial nerve tests were normal. There were no fasciculations of the neck or tongue muscles. He was able to rotate and extend the neck with normal strength, however neck flexion seemed to be compromised. Neil exhibited widespread fasciculations in his arms and legs, and the muscles of these limbs had mildly atrophied. Motor tests were conducted for the arms and legs (4/5), and wrist extensors and intrinsic muscles of the hand (3+/ 5). Neil exhibited hyperactive deep-tendon reflexes and positive Babinski signs bilaterally. Sensory examinations were unchanged.

Based on the compounding symptoms and rapid progression of the disease, doctors suspected that Neil was suffering from amyotrophic lateral sclerosis (ALS), a disease that results in the destruction of upper and lower motor neurons. To confirm this diagnosis, neurologists conducted a series of tests., including nerve conduction tests and needle EMG. Nerve conduction tests of the motor and sensory nerves revealed normal conduction velocities with low amplitude compound motor action potentials, and normal sensory nerve potentials. There were abundant fasciculations and characteristics that suggested remodeling of motor units following denervation. Furthermore, EMG suggested net motor unit loss. There was no evidence of demyelination. Based on these results, doctors confirmed the diagnosis of ALS. For the following weeks, Neil experienced physical therapy aimed to help him preserve his strength and energy. He soon began to experience difficulty swallowing, and his cough progressed. Soon thereafter he developed pneumonia, was placed on a feeding tube, and ultimately died just 15 weeks after his initial hospitalization.

5. Electromyography involves recording electrical activity from muscle fibers. Justify Neil's low amplitude compound motor action potentials given his diagnosis of ALS. Be sure to describe how a muscle fiber initiates and propagates action potentials, and state how that process differs in the case of ALS.

6. Motor unit remodeling includes a reduction in the number of motor units, atrophy of muscle fibers, and an increased number of fibers per motor unit. Describe how motor unit remodeling may be indicative of ALS. Be sure to describe the typical structure and function of a motor unit, a typical distribution of motor unit (and fiber types) within a muscle, and how motor unit remodeling could contribute to Neil's weakness.

7. Based on the etiology of the disease, justify the finding of hyperactive deep-tendon reflexes and positive Babinski signs bilaterally in a patient suffering from ALS. Be sure to describe a typical reflex, and describe how descending inhibition may modulate a reflex response.

8. Justify why Neil's motor tests progressively worsened, whereas sensory, and cognitive tests remained unchanged. Be sure to describe the central and peripheral nervous system structures required for perception versus movement, and identify where deficits may be found in a patient with ALS.

Answer question part a-d

Question part A

Diffusion Lab

Purpose: To investigate the diffusion of a substance across a semipermeable membrane.

Materials:

iodine (must be colored, clear won't work)

cornstarch/water solution

plastic sandwich bags (cheap is good)

beakers or clear plastic cups

Set-Up and Procedure
1. Fill beaker about halfway and put about ten drops of iodine.
2. Put about a teaspoon of starch and about 3 ounces of water in baggie and tie.
3. Make sure that it is water tight
4. Put the baggie in the beaker or glass and wait.
5. In about 15 minutes the solution in the baggie will turn blue/black. (purple)
This is a result of the iodine diffusing through the bag.
You should know that iodine is an indicator for starch. It turns blue/black in color.
Test it by dropping some iodine on a piece of white paper.

Questions and Conclusions :

Define permeability

To which substance is the plastic bag is permeable ?

Why did the iodine enter the bag ?

Why didn't the starch enter the beaker?

How is the plastic bag like the cell membrane?

Question part b

Reflex Lab

Procedures for Reflex Lab

In this lab we will test muscle stretch reflexes and cutaneous reflexes.

A partner is needed to be the subject for this lab.

Purpose: To test and observe normal muscle stretch and cutaneous reflexes.

Equipment: Reflex hammer,

Background: In the most narrow sense, a reflex is an involuntary, unpremeditated response by the body to an external stimulus. Reflexes allow reaction to a stimulus more quickly than would be possible if conscious thought were involved. A reflex can be described as a stimulus-response cycle. Most reflexes involve the brainstem or the spinal cord and do not require interaction from higher brain centers. The muscle stretch reflexes are the simplest reflexes. They involve the sensory neuron synapsing directly upon the motor neuron. They are sometimes called monosynaptic reflexes. They are also called spinal reflexes because the reflexive action does not require input from the brain. The other reflexes we will be testing in this lab are the cutaneous reflexes. They are also called superficial reflexes because the receptors are in the superficial areas of the body. They are more complex and require the message to go up the spinal cord to the brain and then back down to elicit the response. These can be used to test for CNS injury.

There are five components to a reflex; these components together are called the reflex arc. The components are as follows:

sensory receptor â receives the stimulus and generates an impulse (is usually a nerve ending)

afferent pathway â a neuron that carries the impulse from the receptor to a central integrating center

integrating center âthis is where the afferent component connects to the efferent component- this is in the CNS. One or more synapses must occur here. Interneurons are not involved in stretch reflexes but are always found in all other types of reflexes.

efferent pathway - a neuron that carries the impulse from the integrating center to an effector.

effector -receives the impulse and responds. The effector may by skeletal muscle, smooth muscle, or glands.

For more information please read chapter 12 : "Muscle" ( Pages 380-390) in Human Physiology book ( 12th edition by Stuart Ira Fox)

Part I. Stretch reflexes.

First do muscle stretch reflexes which are also called deep tendon reflexes.

It is important the subject relax the muscle being tested. Tell the subject to let the muscle go limp.

Rate each response according to the following scale:

+4 very brisk, hyperactive, large movement at joint.

+3 brisker than average, medium movement at joint

+2 average, small movement at joint

+1 somewhat diminished, very small or no movement at joint

0 no response

1. A subject is allowed to sit comfortably on a table with knees dangling over the edge.

2. Using a reflex hammer (or substitute as described above) strike the patellar tendon just below the kneecap.

3. Observe the action caused by the reflex.

4. Record your results using the graded scale above.

B. Biceps Reflex â activation of the musculocutaneous nerve

1. Rest subjectâs left forearm along your left forearm.

2. Subjectâs hand should rest in or near the bend of your elbow.

3. Press your left thumb on the subjectâs biceps tendon, apply a little pressure.

4. Strike your thumb with the reflex hammer, this will transfer the pressure to the biceps tendon.

5. Watch carefully for twitching of the biceps muscle. Usually, the forearm will not move.

6. Record your results using the graded scale above.

C. Triceps reflex â activation of the radial nerve.

This is a difficult reflex to observe, but give it a try.

1. The subject should have the arm relaxed and elbow bent.

2. Support the entire weight of the arm with your left hand.

3. Strike the triceps tendons, just above the elbow.

4. Watch carefully for twitching of the biceps muscle.

5. Record your results using the graded scale above.

Both B and C show up best on someone who doesnât have a lot of subcutaneous fat and who has good muscle definition.

1. Have the subject take her/his shoes and socks off, exposing the Achilles tendon on the back of the ankle.

2. Strike the Achilles with the reflex hammer (or substitute) and observe the extension of the foot downward.

3. Record the results using the graded scale above.

Part II. Cutaneous reflexes

A. Plantar reflex

1. The subject needs to lie on his or her back, with shoes and socks off.

2. Using the end of the handle of the reflex hammer, trace a path along the lateral side from heel to the little toe to the big toe.

3. Observe for the flexion (toe curling) which is recorded as a normal plantar reflex.

5. Record the results.

1. Pinch the back of the subjectâs neck,

2. Watch pupils for a response.

3. A normal response is dilation of the pupil.

4. Record your results.

question part c

Homeostasis Lab - Heart Beat Regulation

This lab is designed to help explore the process of homeostasis as it applies to regulating heart rate. It also should help how a sampling process works.

Make two copies of the data sheet (or make your own) and paste them into your report.

1. Take a pulse for six seconds, record this number in the table below.

2. Every 15 seconds for the next three minutes, take a pulse again for six seconds, record each of these values.

3. Multiply each of these values by 10 to get the beats per minute.

4. Now average these numbers (this is the setpoint for the pulse at resting). Note the range of values (that is how far they can deviate from the set point).

5. The next step is to take a 30 second reading. Multiply this number by 2 to get beats per minute.

6. How does this compare to the setpoint?

7. Repeat steps 1 through 6 after running in place for 30 seconds. Record the same data.

8. After getting 8 readings, stop and plot these numbers on a piece of graph paper. The X-axis should be minutes and the Y-axis should be heart rate.(Don't forget to connect the points ). You can do this in Excel and then import it into Word. Or you can e-mail this to me.

Submit your lab report in the correct format.. Respond to the questions above. Explain WHY the results were what they were. Compare the resting and post-exercise and postulate explanations for the differences. You should have two data tables and one graph with your heart rate data from both tables on it in your report.

Time in seconds	Heart rate (bpm)
0 (initial recording)
15
30
45
60
75
90
105

question part d

What was one thing you found interesting, confusing or surprising about any of the lab activities? Why?

Weekly leaderboard

Home

Homework Help 3,900,000

Biology 460,000

Unlock all answers

Related textbook solutions

Molecular Cell Biology

Biology: Science for Life with Physiology

Biology

Concepts of Biology

Essentials of Biology

Related questions

Related Documents

BIO 203 Study Guide - Quiz Guide: Polonium Dioxide, Proximal Tubule, Glutathione

BIO 240 Lecture Notes - Lecture 10: Gastrocnemius Muscle, Defecation, Axial Skeleton

BIO 12D Lecture Notes - Lecture 15: Erector Spinae Muscles, Lumbar Vertebrae, Latissimus Dorsi Muscle

Weekly leaderboard