Lab 7- the muscular system- eScience Labs PDF

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Lab 7- the muscular system for Anatomy and Physiology 1-through eScience Labs...

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The Muscular System PRE-LAB QUESTIONS 1. How do banding patterns change when a muscle contracts? a. When a muscle contracts, banding patterns change as the thick filaments are pulled towards the sarcomere’s center. Myofilaments are not changing in size, but the actin is sliding past the myosin which changes the appearance of the band thickness 2. What is the difference between a muscle organ, a muscle fiber, a myofibril, and a myofilament? a. A muscle organ is a complete muscle system with skeletal, smooth, and cardiac muscle, whereas a muscle fiber (or myocytes) is a muscle cell which is made of myofibrils, myofibril which are formed within muscle fibers made of actin (thin/light) and myosin (thick/dark), these myofibrils are organized into thick (dark) and thin (light) filaments which are named myofilaments 3. Outline the molecular mechanism for skeletal muscle contraction. At what point is ATP used and why? a. For skeletal muscle contraction, ATP is used as chemical energy, converted to mechanical energy during a muscle contraction. First Ca^2+ is released from sarcoplasmic reticulum, binding with troponin, causing a positional change in tropomyosin, causing a shift which exposes myosin binding sites on the actin, the ADP +P then attaches to the actin causing a cross-bridge, releasing ADP and P altering the myosin heads, creating a sliding motion causing actin to move to the center of the sarcomere. ATP binds to the myosin, hydrolyzing ATP into ADP and P returning energy to myosin heads. This cycle ends when Ca is pumped back into the sarcoplasmic reticulum 4. Explain why rigor mortis occurs. a. Rigor mortis occurs after a person expires. When a person dies, the process to recycle ATP stops as the person is no longer breathing (oxygen required to make ATP). The stored ATP is quickly depleted, meaning the myosin and actin remain linked, leaving the body contracted. Rigor mortis goes away as muscles start to decompose.

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The Muscular System EXPERIMENT 1: TENDONS AND LIGAMENTS Post-Lab Questions 1. Identify the components in the slide image below based on your observations from the experiment.

A___Chondrocytes____________ B_____Collagen __________

2. Identify the components in the slide image below based on your observations from the experiment.

A__nucleus_____________

B__skeletal muscle fibers_____

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The Muscular System 3. Identify the components in the slide image below based on your observations from the experiment.

A ___Nuclei____________ B ____Collagen Fibers___________

1. How does the extracellular matrix of connective tissues contribute to its function? a. The extracellular matrix of CT contributes to its function of binding and supporting the cells together. The matrix helps to regulate, divide, and support the tissues including controlling intercellular communication 2. Why are tendons and ligaments difficult to heal? a. Tendons and ligaments are difficult to heal because they have a lower supply of blood. A strong blood flow is required for quick healing, which is why ligaments are the most difficult to heal. 3. What differences do you see between the tendon-muscle insertion images and the tendon images? a. The differences I noted between the tendon-muscle insertion and tendon images were in the tendon-muscle insertion image you could see a clear difference between the muscle fibers and tendon regions. I also noted collagen and chondrocytes in the tendon-muscle, but did not note any chondrocytes in the tendon. ©eScience Labs, 2016

The Muscular System 4. What differences do you see between the tendon and ligament images? a. The differences I noted between the tendon and ligament images were that the ligaments had more straight longitudinal activity where as the tendon still had longitudinal activity but thinner, with more curvation, ligaments are much thicker with skeletal muscle

EXPERIMENT 2: THE NEUROMUSCULAR JUNCTION Post-Lab Questions Identify the axon, terminal branches, and muscle fibers in the slide image below. If possible, trace the fiber to its terminus.

1. Are there few or many nuclei at the end plate? a. At the end plate, there are many nuclei 2. What is a motor neuron? a. A motor neuron is a neuron that stimulates muscles. They are responsible for the nervous system’s motor response 3. How is greater muscle force generated (in terms of motor unit recruitment)? ©eScience Labs, 2016

The Muscular System a. Greater muscle force is generated by force summation. Skeletal muscles can engage different numbers of muscles with fast or slow frequencies. When additional force is needed, successive stimuli can create additional tension (individually twitch muscles 4. What types of sensors are present within the muscle to identify how much force is generated? a. The sensors that are present within the muscle are proprioceptors

EXPERIMENT 3: MUSCLE FATIGUE Data Tables Table 2: Experimental Counts Trial 1

Trial 2

Trial 3

Trial 4

Trial 5

Predicted Value

20

18

16

14

12

Actual Value

32

31

24

23

23

Post-Lab Questions 1. How did the predicted results compare to the actual results? a. The predicted results compared to the actual results were similar in that they both went down, but I was able to do more than I originally anticipated. 2. Did you notice any changes in the number of repetitions you could perform or how your hand felt after each trial? a. I noticed the more repetitions I did, my hand felt weaker and weaker. It got progressively harder to complete each trial. It felt like my other fingers were trying to compensate, but I was able to get closer to the original trial than originally predicted. My fatigue and strength to complete trial 5 was much more prominent, it was much easier to complete trial 1. 3. Explain the actions that were occurring at the cellular level to produce this movement. Include sources of energy and any possible effect of muscle fatigue. a. The actions that were occurring at the cellular level to produce this movement are ATP facilitating muscle contraction. b. Muscle fatigue can be caused by depletion of ATP 4. Hypothesize what would happen if you restricted blood flow during the experiment. a. If blood flow were restricted during this experiment, I hypothesis I would not be able to complete all trials, and the ones I could, would be severely limited in production/abilities

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The Muscular System EXPERIMENT 4: GROSS ANATOMY OF THE MUSCULAR SYSTEM Table 3: Gross Anatomy Data Movement

Muscle(s) Activated

Action(s) of Muscle(s)

Forearm Extended (Step 1)

Brachioradial muscle Brachial muscle Deltoid muscle Triceps

Support arm to lift and extend away from the body

Fingers Extended and Splayed (Step 1)

Radial flexor muscle of wrist Long radial extensor of muscle of wrist (if hand folded back) Short flexor muscle of little finger Short abductor muscle of thumb

Flex muscles to extend fingers outward

Fingers Retracted (Step 1)

Adductor muscle of thumb Ulnar flexor muscle of wrist

Flex muscles to extend fingers inward

Forearm Pressed Down Upon (Step 2)

Deltoid muscle

Muscles flex to meet the pressure to withstand pushing down

Elbow Bent (Step 3)

Round pronator muscle Pronator quadratus muscle Deltoid muscle Bicep Brachii

Contracting muscle to move forearm adduction towards body (inward rotation – pronation)

Arm Raised to Side with Heavy Object (Step 4)

Deltoid Bicep Brachii Triceps of arm

Support arm to lift and extend away from the body (abduction) extra support exerted to meet needs of extra weight

Arm Extended Back with Heavy Object (Step 4)

Deltoid Bicep Brachii Triceps of arm

Support arm to lift and extend away and back from the body (abduction) extra support exerted to meet needs of extra weight, shoulder abduction

Rotating Ankle

Superior extensor retinaculum Calcaneal tendon

Support ankle to move in rotation

Spreading Toes

Short extensor muscle of great toe Dorsal interosseous muscle of foot

Allow toes to flex, spread and extend ©eScience Labs, 2016

The Muscular System Movement

Muscle(s) Activated

Action(s) of Muscle(s)

Pointing/Flexing Toes

Short extensor muscle of great toe Dorsal interosseous muscle of foot Long extensor muscle of toes

Extension of foot and support lifting of toes to point

Bending Knee

Soleus muscle (L or R) Anterior tibial muscle Long fibular muscle

Adduction of lower leg to flex towards the body

Extension of Foot

Soleus muscle (L or R) Anterior tibial muscle Long fibular muscle

Allows for adduction of foot away from the body

Extension of Leg

Vastus Lateralis Muscle Vastus Medialis muscle

Supports leg to extend and stabilize

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The Muscular System Post-Lab Questions 1. Label the human muscle diagram

A__ Greater Pectoral muscle____

B___ radial flexor of the wrist (or ulnar flexor of wrist depending on where arrow truly pointing to)

C____ Vastus Medialis _____

D_____ Bicep Brachii ___________

E____ radial flexor of wrist (or long p depending on where the arrow is truly pointing)

____________

F_____ no F listed?___________

G___ straight muscle of the thigh

H____ Anterior Tibial __________

1. Which muscle(s) were used to extend your arms backward? a. Muscles that were used for a backwards extension would be posterior deltoid, teres major, and latissimus dorsi 2. Which muscle(s) were used to extend and splay your fingers outward? a. Muscles that were used to extend and splay the fingers outward are the extensor digitorum

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The Muscular System EXPERIMENT 5: ATP AND MUSCLE FATIGUE Data Tables Table 4: Muscle Fatigue Data Trial

Time (seconds)

Trial 1

57 SECONDS

Trial 2

68 SECONDS

Trial 3

54 SECONDS

Post-Lab Questions 1. What happened to the time intervals between Trial 1 and Trial 3? What caused this change? a. The time intervals between Trial 1 and Trial 3 decreased slightly. This change was caused by muscle fatigue. (Note. I believe the second trial was longer because I was not looking at the stopwatch, and was feeling more stubborn so may have pushed a bit harder unintentionally- I would have hypothesized for each trial to decrease gradually) 2. Identify three muscles that were engaged during the wall-sit. a. Three muscles that were engaged during the wall sit are i. Vastus medialis ii. Vastus lateralis iii. Gluteus maximus 3. Explain the biochemical reasoning behind muscle fatigue. a. The biochemical reasoning behind muscle fatigue is that the supply of ATP is depleted. Once the body has a chance to catch up to produce more ATP, it can exert more energy to contract muscles. (I.e. if there was not a rest period between the trials, I would hypothesize that the trials would have lasted shorter than they did)

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The Muscular System Experiment 6: Virtual Model – The Muscular System (Upper Body) Post-Lab Questions 1. What is the term for the muscles of the mouth? a. The term for the muscles of the mouth is “orbicularis oris muscle”. The Virtual Human Body website lists the function as allowing the lips to close, purse and pucker. 2. What is the scientific name of the muscle that facilitates the raising of the lower lip? Is it on the ventral or dorsal side of the body? a. The scientific name of the muscle that facilitates the raising of the lower lip is called the mentalis muscle (L or R) (small chin muscle allowing lip to be pushed out or raised). It is on the ventral (front) side of the body. 3. Which muscle is deeper in the body: the internal oblique muscle or the transverse abdominal muscle? a. The transverse abdominal muscle is deeper in the body 4. Is the trapezius muscle located in the abdomen, back, head, neck, or thorax? a. The trapezius muscle is located on the posterior side of the body, in the upper back, thorax and neck 5. What muscle is medial to the deltoid muscle? a. The muscle medial to the deltoid muscle is the greater pectoral muscle (more towards the middle line)

Experiment 7: Virtual Model – The Muscular System (Lower Body) 1. What is the role of the long extensor muscle of the toes? Which toes does it control? a. The role of the long extensor muscle of the toes is to control/allow the last four toes to extend, and to connect the fibula and lateral condyle of the tibia to the four toes. 2. How many adductor muscles exist within the body? List them here. a. There are three adductor muscles in the body (all located in the upper thigh area) brevis is most superior, with magnus most interior). In list form they are: i. Adductors magnus ii. Adductors brevis iii. Adductors longus 3. Is the gracilis muscle located in the foot, hip, leg, or thigh muscle group? a. The gracilis muscle is located in the thigh area (medial to long adductor muscle/straight muscle of thigh) 4. Relate the location of the semitendinous muscle and the greater gluteal muscle. a. The location of the semitendinosus muscle is inferior to the greater gluteal muscle 5. Which muscle is most distal: the pectineal muscle, the soleus muscle, or the abductor muscle of the great toe? a. Of the above listed muscles, the abductor muscle of the great toe is the most distal muscle. (Soleus muscle is posteriorly placed, superior to the ankle, pectineal muscle is medial placed superior to both soleus, and abductor muscle of great toe. ©eScience Labs, 2016...