Lab 5: Skeletal and Muscular Systems - Biology 067 -...

Biology 067_VIU_skeleton/muscle_Fall 2015 version

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Lab 5: Skeletal and Muscular Systems LABORATORY OBJECTIVES

Identify a male versus a female skeleton

Identify the bones that make up the human body

To investigate articulations and synovial joint movement

To investigate muscles and bones working together-using dissection of a chicken wing

muscle fatigue

INTRODUCTION:

Our skeletal and muscular systems work together to support our bodies and allow us to move in the various ways we do. The skeletal system also does other important things for our bodies; it protects our soft body parts, produces blood cells, and stores minerals and fats. Our muscular system also has other functions; it helps maintain internal body temperature and assists with movement of fluid in our veins and lymphatic vessels - it also protects the organs of the abdominal region, and stabilizes joints. ACTIVITY 1: Is the skeleton male or female? MATERIALS

Sammy the skeleton (Sammy could stand for Samuel or Samantha!) METHODS

“The pelvis tells the story1: Distinct features adapted for childbearing distinguish adult females from males. Other bones and the skull also have features that can indicate sex, though less reliably. In young children, these sex-related features are less obvious and more difficult to interpret. Subtle sex differences are detectable in younger skeletons, but they become more defined following puberty and sexual maturation.”

The differences:

Female pelvic bones Male pelvic bones

Broader sciatic notch Narrower sciatic notch

Raised auricular surface flat auricular surface

1 From Smithsonian Institute: http://anthropology.si.edu/writteninbone/comic/activity/pdf/skeleton_male_or_female.pdf


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Figure 1. Female and male pelvic bones. (Source: Smithsonian Institution)

DISCUSSION QUESTIONS

1. With the help of the above information and diagram, look at Sammy the skeleton – Is it male or female? Describe how you could tell.

ACTIVITY 2: The human Skeleton MATERIALS

The skeleton

Skeleton diagrams of the axial and appendicular skeleton identifying bones

METHODS

1. Using the following list, draw a table similar to the one below and place the bones in the appropriate columns. Include this table in your data and observations.

Skull Arm bones ribcage

pectoral girdle hyoid pelvic girdle

vertebral column leg bones


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Appendicular Skeleton Axial Skeleton

2. Identify the parts of Sammy’s skeleton, and then photocopy, trace or draw a diagram similar to the following page, label the bones on your diagram. Include your diagram in the data and observation section of your lab report.

There are no discussion questions for this activity.


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ACTIVITY 3: Articulations and Movements of synovial joints The bones of the human body are joined together at joints. There are three types of joints: fibrous joints are the sutures that join the cranial bones and are immovable; cartilaginous joints are slightly moveable and are joined together by either hyaline cartilage (i.e., costal cartilage joining ribs to sternum) or fibrocartilage (i.e., intervertebral discs); synovial joints are freely moveable and involve ligaments which connect bone to bone.

All synovial joints have the same components2:

Two common types of synovial joints are ball and socket (hips and shoulders) and hinge joints (elbows and knees) –although you don’t need to learn these at this point…for your interest, other types of synovial joints are: plane joints (intercarpal joint), pivot joint (proximal radioulnar joint), saddle joint (carpometacarpal joint of thumb), and condyloid joint (metacarpophalangeal joint)

2 Diagram from: http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/2_anatomy_skeleton_rev3.shtml


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MATERIALS

Skeleton

METHODS

1. On Sammy, feel and observe the following types of articulations: a) Fibrous joints b) Cartilaginous joints c) Synovial joints

2. Flexion versus extension

a) Stand up b) Using the diagram below to help you, demonstrate

to your partner flexion and extension c) Answer the following questions in the discussion

part of your lab report:

With flexion, does the joint angle increase or decrease?

With extension, does the joint angle increase or decrease?

3. Adduction versus Abduction a) Stand up b) Using the diagram below to help

you, demonstrate to your partner adduction and abduction

c) Answer the following questions in the discussion part of your lab report:

With adduction, does the body move towards or away from the midline?

With abduction, does the body move towards or away from the midline?


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4. Rotation versus circumduction a) Stand up b) Using the diagram below to help you,

demonstrate to your partner rotation and circumduction

c) Answer the following questions in the discussion part of your lab report:

Describe rotation

describe circumduction

5. Answer the following questions in the discussion

part of your lab report: a) Where are the fibrous joints and are they movable or immovable?

b) What kind of cartilage joins cartilaginous joints and give an example where each is

found.

c) What are two types of synovial joints and give an example where each is found.


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ACTIVITY 4: Chicken wing dissection – bone and muscle working together3 INTRODUCTION There are many differences between the anatomy of humans and chickens, however, we can study muscle pairing and range of motion in humans by looking at a chicken wing. Chicken wings are very similar to the arm and hand of humans due to a shared evolutionary history.

3 The concept and procedure for this activity from://www.biologyalive.com/


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We will review the bones of the human arm so that we can compare it to the chicken wing. The bones of the upper part of the appendicular skeleton extending out from the pectoral girdle are: the humerus (long bone of

the upper arm), the ulna and radius, (bones of the forearm), the carpals (wrist), the metacarpals (palm of the hand), and the phalanges (fingers and thumb) – the similarities to a chicken wing can be seen by comparing the two figures above.4 In the chicken, the upper wing is the humerus and the lower wing is the ulna and radius. The upper and lower wing are connected at the elbow joint. The bones at the wing tip consist of modified hand bones. Like the skeleton, the muscle groups of the chicken wing work in a similar manner to that of the human. Connective tissue, called tendons, connect the skeletal muscle to bone; when the muscle contracts and shortens between two bones (in this case, the biceps muscle that goes from the shoulder to the lower arm – note diagram), the bones of the lower arm are brought closer to your shoulder. When you wish to extend your arm, the tricep muscle contracts and the bicep muscle extends allowing the arm to extend. As one muscle contracts, the other extends, and therefore, they work together to make the limbs move.

4 Diagrams from http://www.biologyalive.com/


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CAUTION: You will be dealing with raw chicken which can be contaminated with Salmonella. Throughout the procedure, USE GLOVES and keep your hands away from your face and mouth at all times. Make sure to wash thoroughly following the dissection and clean your station with 5% bleach solution or disinfectant and rinse 3 times with very hot water. MATERIALS

Chicken or turkey wing

dissection kit

METHODS 1. Work in partners

2. Examine your chicken wing and

compare it to your arm and hand – while the skin is still on, identify on both where the: humerus, ulna, radius, carpals (wrist bones), metacarpals (hand bones), and phalanges (finger bones) are found.

3. Using your dissection scissors cut the skin lengthwise as per the diagram of cut 15, identifying the upper and lower wings and wing tip to orient your cut correctly – follow the line of the arrow –cut until you reach where the wing would have attached to the shoulder joint. DO this carefully by first piercing the skin and then sliding your scissors under the skin layer – Try not to cut too deep or you will cut into the muscle.

4. Make another cut starting at the first cut and go in both directions as per cut 2 on the diagram. Very carefully peel the skin back, cutting when necessary – removing the skin can be difficult and must be done with caution to avoid damaging the tissue beneath.

The yellow tissue beneath the skin is fat tissue,

whereas the muscles will appear pale pink.

5 Diagrams from http://www.biologyalive.com/


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5. Examine the wing now that the skin is removed, and identify the two muscles that bend

and straighten the elbow joint. The flexor is the muscle that bends the joint, and the

extensor pulls the bone to straighten the joint. Hold the wing down at the shoulder

joint and pull on each muscle alternately, observing what happens.

6. Observe the tendons which are the shiny white tissue that attaches the muscles to the

bone – again pull on the tendons and observe what happens.

7. Observe the action at the joint by bending and straightening the elbow joint.

8. Examine the joint and try and find the ligaments that join bone to bone – they appear

like a shiny white covering of the surfaces of the joint.

9. Identify the cartilage which is the slippery, shiny white material between the bones.

The cartilage helps the bones slide past each other without grinding or friction.

10. Observe the wing as a whole and examine how the bones, muscles, tendons, ligaments

and cartilage work together to allow the wing to move.

11. Everyone must identify and describe each part of the wing and how they work to their

partner.

‘Making the Human Connection’5

“With your left hand grasp something with weight such as a heavy textbook or pencil pouch and hold it at your side. Place your right hand on your upper left arm so that you can feel your muscles move. Slowly bend your left arm to raise the weight. Then slowly straighten your left arm to lower it. Repeat this motion a few times until you can feel and see what is happening."6

DISCUSSION QUESTIONS

1. When you lifted the weight, what joint were you

using?

6 Diagram and activity explanation from http://www.biologyalive.com/


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2. Describe which muscle was contracting and which muscle was extending when you

LIFTED the weight.

3. Describe which muscle was contracting and which muscle was extending when you

LOWERED the weight.

4. Explain which bone(s) moved and which bone(s) did not move.

ACTIVITY 5: Muscle fatigue A whole muscle can contain many motor units – a motor unit is a nerve fiber with all the muscle fibers it innervates. When the intensity of nervous stimulation increases, more motor units in a muscle are activated - this is called ‘recruitment’. If a motor unit receives a rapid series of stimuli it can respond to one stimulus before relaxing from another. The term summation is used to describe increased muscle contraction until maximum contraction is reached. Maximum contraction is called tetanus (not the same as the infection called tetanus!). Tetanus continues until the muscle fatigues due to depletion of energy reserves. Fatigue is evident when a muscle relaxes even when it is receiving a stimulus to continue. The following graphically shows this process:

MATERIALS7

a tennis ball

timer with seconds or a clock with second hand

7 All diagrams not referenced previously from Instructors version of: www.mhhe.com/maderhuman12e


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METHODS

1. Work in partners

2. Sit at a table and lay your arm flat with your palm up, holding the tennis ball

3. For 30 seconds - squeeze and release the tennis ball repeatedly as many times as you can, completely opening your hand every time – your partner will time you for 30 seconds.

4. Rest for 30 seconds

5. Repeat this process for a total of five times.

6. Change places with your partner and let them go through the exercise.

7. Explain in the discussion question section of your lab report, what is happening to your muscles?

Lab 5: Skeletal and Muscular Systems - Biology 067 -...

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