STEM Club: The Respiratory System

The cells of the human body require a constant stream of oxygen to stay alive. The respiratory system provides oxygen to the body’s cells while removing carbon dioxide. 

There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration. The airway, which includes the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles, carries air between the lungs and the body’s exterior.

The lungs act as the functional units of the respiratory system by passing oxygen into the body and carbon dioxide out of the body. Finally, the muscles of respiration, including the diaphragm and intercostal muscles, work together to act as a pump, pushing air into and out of the lungs during breathing.

bromoblue

Exhaling Carbon Dioxide (demonstration)

I gave each of the students a cup of water to which I added a few drops of bromothymol blue (a chemical that is often used to test water in fish tanks and can thereby be purchased at pet stores).  I then gave each student a straw and instructed them to blow bubbles into the water, being careful not to invest or inhale through the straw. Within a few minutes, the water began to change color – eventually turning a faint yellow color.

Note: We used filtered water from our refrigerator but the lab instructions called for distilled. A fun inquiry project would be to test if the color varies with different types of water.

Bromothymol blue is an  acid indicator and will thereby turn blue in a basic or neutral solution and green or yellow-green in an acidic solution. The water was thereby light blue in appearance. When carbon dioxide mixes with water, it forms a weak acid called carbonic acid. This acid turns the bromothymol blue a green or yellow-green color.

 

lungAir Chamber (demonstration)

The model shown here simulates the contraction of the diaphragm (the plastic swim cap) and the resulting rush of air into the lungs (the balloon inside the bottle). Build one yourself so students can visualize the process that take place in their chest cavity.

Materials

  • 2-liter bottle with the bottom cut off
  • Hammer and nail to poke a hole in the lid
  • A straw inserted into this hole and secured in place with clay or glue
  • A balloon taped securely onto the other end of the straw
  • A swim cap held in place with a rubber band

When you inhale, your diaphragm, a band of muscles at the bottom of your chest cavity, contracts. When your diaphragm contracts, it flattens and pulls downward – just like when you pull down on the plastic swim cap on the bottom of the model. As it does, the volume of your chest cavity increases and the pressure inside it decreases. The pressure of the air outside your body is then greater than the pressure inside the chest cavity, so air rushes in through your mouth and nose.

When you exhale, your diaphragm relaxes and returns to its original shape, decreasing the volume and increasing the pressure of air in your chest cavity. This forces air out of your lungs.

Lung Capacity Activity

In advance, I calibrated a clean plastic milk jug (marking off 1-cup increments with a permanent marker on the side). I then inverted it in a sink about half full of water, being careful so that the water doesn’t come out of the jug. Holding the jug steady so it doesn’t fall over (another set of hands is helpful), I inserted a long rubber tube (approximately 60cm) into the jug.

I then asked for a volunteer to take a big breath and exhale into the open end of the tube. As he blew, the water inside the jug was forced out and replaced with the air he exhaled (Carbon Dioxide and other trace gases). We were then able to measure the amount of air he breathed out using the change in water level.

Bring it Home

  • Measure your own lung capacity using a calibrated milk jug as I described above. How does your lung capacity compare to that of your parents or siblings? your friends?
  • How does your lung capacity change with exercise?
  • Why do some athletes (distance runners) train at high altitudes?
  • What is Emphysema, Pneumonia, Bronchitis and Sinusitis?

 

STEM Club: The Digestive System

The Digestive System is a group of organs working together to convert food into energy and basic nutrients to feed the entire body. Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract (GI tract). The alimentary canal is made up of the oral cavity, pharynx, esophagus, stomach, small intestines, and large intestines.

There are several important accessory organs that help your body to digest food but do not have food pass through them. Accessory organs of the digestive system include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas. To achieve the goal of providing energy and nutrients to the body, six major functions take place in the digestive system:

  • Ingestion
  • Secretion
  • Mixing and movement
  • Digestion
  • Absorption
  • Excretion

There are two types of digestion – mechanical (chewing, stomach sloshing, peristalsis, etc.) and chemical. Chemical digestion is only possible because your body gets help from enzymes! An enzyme is a type of protein that speeds up how quickly a chemical reaction happens in your body.

digestivesystemEnzyme Labs

Amylase

There are about 700 different enzymes in the body. Amylase is an enzyme that breaks down complex carbohydrate molecules into simpler, sugar molecules. Our salivary glands excrete amylase into our mouth to aide in the digestive process.

Activity 1 :: In the book Head to Toe Science, I came across an activity that I thought would be perfect for STEM Club that was titled “Helpful Spit”. We thereby carried out this activity in class using the following procedure:

  • Divide a plate into four quarters, labeling them as follows: unthawed, 30 seconds, 5 minutes, and 10 minutes. Place a soda cracker in the unchewed section. Place a drop of iodine on the cracker. What happens?
  • Chew another cracker for 15 seconds making sure it becomes well moistened. Place one-third of the chewed cracker in each of the remaining sections. Wait 15 seconds. Place a drop of iodine on the cracker in the 30 seconds section. What happens?
  • Wait five minutes. Place a drop of iodine on the cracker in the 5 minutes section. What happens? Wait another 5 minutes and place a drop of iodine on the cracker in the 10 minutes section. What happens?

Iodine is a chemical that turns dark blue or black when it reacts with starch. We thereby expected the iodine to react with the unchewed cracker by turning dark blue/black and this is exactly what happened.

Saliva is an enzyme present in our saliva and thus the longer it had time to break down the carbohydrates into simple sugar molecules, the less starch would be present to react to the iodine.  We thereby expected that the chewed crackers would show a lighter shade of blue the longer the chewed crackers were left on the plate.

However, there was no discernible difference. Activity fail. We hypothesized what could have gone wrong. What could have affected the outcome of this activity? Not enough saliva? Not enough time?

We tried it again a few days later – assuring the crackers were significantly more moist (more saliva) but again, the same result.

Activity 2 :: An Alternative

Materials:

  • 2 teaspoons starch powder
  • 1 teaspoon amylase powder
  • Distilled water
  • 2 small glasses
  • 1 spoon or stick with which to stir
  • 2 – 3 glucose testing strips (Lab-grade, with color-coding section)

Procedure:

  1. Pour 1 teaspoon of starch powder into each glass.
  2. Label one glass “WA” (with Amylase) and the other “NA” (no Amylase).
  3. Add about 5 mL of distilled water to each glass, stir to mix.
  4. To the glass marked “WA”, add your 1 teaspoon of Amylase powder and stir to combine thoroughly.
  5. Place 1 glucose testing strip into each glass. Record the color that the testing strips turn for each glass; refer to the color-code on the package to determine how much glucose is present in the solution.

Pepsin

Pepsin, which is found in the stomach, breaks down proteins. It takes the proteins from complex structures into simpler structures. Once those simple proteins get to the small intestine, a number of other enzymes continue to break them down into amino acids – which your body loves.

Materials:

  • 1 small piece of tough steak
  • 1/8 teaspoon meat tenderizing powder
  • 1 plate

Procedure:

  1. Using a small knife, carefully cut your steak into two pieces.
  2. Place the steak on the plate, and using your masking tape and markers, label one piece “WP” (with Pepsin) and the other “NP” (no Pepsin).
  3. Carefully sprinkle / cover your steak marked “NP” with the meat tenderizing powder and let it sit.
  4. After several minutes, the meat tenderizers should have had time to do their work. Touch both pieces of meat and record any differences between them in your notebook. What difference do you feel?
  5. Do you think that other animals have adaptive digestive systems that might be different from ours? Imagine a creature’s digestive system based on a diet of either: rocks and stones, twigs and leaves, or only meat. Explain how their digestive system is different from ours, naming all of the organs and how they are different based on the diet that you chose.
  6. Many commercial meat tenderizers (powders that you can put on your steak before cooking it to make the meat more tender) contain enzymes, like the enzyme “papain” which comes from the papaya fruit. What is this analogous to in the human digestive system? How?

Bring it Home

  • Make a record of what you eat each day for the week. Compare your diet tot the recommended daily requirements. What kinds of foods are you eating?
  • Make a cast of your teeth with plaster of Paris.
  • If you have a tooth, crack it open gently by tapping with a hammer and look at the internal parts (enamel, dentin, pulp).
  • Watch this great TED-Ed video, What does the liver do? Write a paragraph describing what you learned.
  • Eggshells are similar in their makeup to teeth; both react to acid in a dramatic way. Design a test to see how different soda pops affect the egg shell.
  • Create a “Wanted” poster for a digestive organ (include the following information:
    • The organ’s role(s)/function(s) in the digestive system
    • The type(s) of digestion it performs
    • What enzymes it utilizes
    • What would happen to your digestive process if you no longer had this organ
  • Test a variety of foods to find what group, or groups, to which your favorite foods belong:
    • Test for Fat: Cut up some brown paper squares. Rub food on the paper and let it dry. If fat is present, light will show through.
    • Test for Starch: Put a drop of iodine tincture on the food. If starch is present, the iodine will turn blue/black.
    • Test for Protein*: Add the food to a solution of potassium or sodium hydroxide. Add a few drops of diluted copper sulfate solution. If protein is present, you will see a pink or bluish color.

*This test requires some chemicals that you may not have. Adult assistance recommended.

STEM Club: The Muscular System

muscular system

The Muscular System

The muscular system is responsible for the movement of the human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person’s body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Muscle tissue is also found inside of the heart, digestive organs, and blood vessels. In these organs, muscles serve to move substances throughout the body. There are three types of muscle tissue: visceral, cardiac, and skeletal.

Visceral Muscle is found inside of organs like the stomach, intestines, and blood vessels. The weakest of all muscle tissues, visceral muscle makes organs contract to move substances through the organ. Because visceral muscle is controlled by the unconscious part of the brain, it is known as involuntary muscle—it cannot be directly controlled by the conscious mind. The term “smooth muscle” is often used to describe visceral muscle because it has a very smooth, uniform appearance when viewed under a microscope. This smooth appearance starkly contrasts with the banded or striated appearance of cardiac and skeletal muscles.

Cardiac Muscle is found only in the heart, cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle tissue cannot be controlled consciously, so it is an involuntary muscle. While hormones and signals from the brain adjust the rate of contraction, cardiac muscle stimulates itself to contract.

The cells of cardiac muscle tissue are striated—that is, they appear to have light and dark stripes when viewed under a light microscope. The arrangement of protein fibers inside of the cells causes these light and dark bands. Striations indicate that a muscle cell is very strong, unlike visceral muscles.

Skeletal Muscle is the only voluntary muscle tissue in the human body—it is controlled consciously. Every physical action that a person consciously performs (e.g. speaking, walking, or writing) requires skeletal muscle. The function of skeletal muscle is to contract to move parts of the body closer to the bone to which the muscle is attached. Most skeletal muscles are attached to two bones across a joint, so the muscle serves to move parts of those bones closer to each other.

Skeletal muscle cells form when many smaller progenitor cells lump themselves together to form long, straight, multi-nucleated fibers. Striated just like cardiac muscle, these skeletal muscle fibers are very strong. Skeletal muscle derives its name from the fact that these muscles always connect to the skeleton in at least one place.

musclegroupsExercising Muscle Groups – Whole Group Demonstration

The kids had a lot of fun with this activity – I hadn’t expected that they would enjoy it so much. In groups of three, students took turns to do a few lifts I first demonstrated. I chose to do bicep curls, bench press, and squats – but any weight lifting exercise will work.

Students should choose weights which are comfortable to use, but heavy enough to do 15-20 reps. Students rotate three times (each time a new exercise is demonstrated) so students have the opportunity to do each task.

  • The lifter of each group will slowly lift the weight up and down in a “bicep curl” with their dominant arm.
  • The other group members will observe all muscle groups working/moving while the lifter is doing the bicep curls. One member can use a skin-safe marker to circle the muscles that are being used.
  • All students should then write down exactly what type of movements the group observed while the bicep curls were happening.

Students should then switch group roles, and then repeat the steps listed while performing a “bench press” exercise with the weights and finally the “squats”.

Encourage students to make a sketch of what they believe the circled muscles should look like after recording their observations and circling the muscle groups that are moving on the arms of the lifters. Students will need to consider where each muscle connects to the bones in order for them to be activated during each different exercise movement.

Muscle Fatigue Lab – How does fatigue affect performance?

I then led the group through a lab activity that is perfect for integrating math skills – graphing, finding mean and range, and finding percent of decrease and increase. I was the timer for the whole group and I trusted each student to count

Each student places their right forearm flat on a table so the back of the fingertips are flat on the tabletop. He/she closes and opens the right hand as fast as possible until the timer says stop, being sure the fingertips touch the palm when closed and the fingertips touch the table when open.

The timer times each trial for 30 seconds and upon calling stop, students record their count on a data table or chart in their notebook. This process is repeated for six 30-second intervals with one 30-second rest interval between the 3rd and 4th trial.  After the activity has been completed for the right hand, repeat the steps for the left hand.

Using the data collected students are then instructed to create a graph. The data and graph can then be used to discuss the results of the activity.

Bring it Home

  • Calculate your horsepower. Weigh yourself on a bathroom scale (pounds). Measure the vertical height of a flight of stairs (meters). Use a stopwatch to record the time it takes you to walk up the stairs (one step at a time). Calculate your weight in newtons (your weight in pounds multiplied by 4.45). [A newton is a unit of force – in this case, the force of gravity that you must overcome to climb the stairs.] Calculate the work you did climbing the stars in joules (your weight in newtons multiplied by the distance or height of the stairs). Calculate the power in units called watts (work in joules divided by the amount of time it took). Lastly, calculate the horsepower used by dividing the watts by 746 [one unit of horsepower (hp) is equal to 746 watts] .
  • Gluteus maximus, soleus, sartorius – why do we call muscles by Latin names?
  • Keep an exercise chart for one week. At the end of the week, evaluate your effort. How well are you exercising? Write a good health goal to improve. List three steps you can take to reach your goal.
  • Are you an athlete? A swimmer, runner, or basketball player for example. Research the muscle groups that are most used by athletes in your sport of choice and write a 5-paragraph essay describing how these muscles are used and what one can do to strengthen these muscles. This activity choice will count for two points.
  • What is muscular dystrophy?
  • Present a simple exercise routine done to your favorite music.
  • Interview a coach and ask about sports-related injuries to the muscular system. Share what you learned with the class.
  • Take a poll. Ask your friends and family how much time they spend on daily exercise. Create a graph to share the results.
  • Learn how to control the muscles in your face. Find a diagram online or in a reference book of the facial muscles. What muscles do you use to: a) open / shut nostrils, b) pull scalp back / down, c) pull ears back, d) raise ears, e) open mouth wide, f) wink with one eye, then the other, g) pull top lip down, and h) pull mouth corners up / down.
  • Cut apart a chicken leg (drumstick and thigh still attached) and carefully observe how they are attached to the bone. Also look at the joint. Sketch and label in your notebook
  • If you and your child think of other activities, go for it!!

My kiddos wanted to create a skit to share what they had learned about the importance of dynamic stretching before exercise as well as what to do in case of a sports related injury. Here is their video that I originally posted to Facebook:

Next week in STEM Club, we will explore the Digestive System.

STEM Club: Skeletal System

The bones in the human body make up the Skeletal System.  Bones serve several purposes. In addition to giving the body structure, they protect important body parts. For example, the skull protects the brain. The tissue inside bones, the bone marrow, makes blood cells and stores fat. Also, bones house nerves and work with the muscles to help us move.

We likely all know what a bone looks like from the outside. But what do they look like on the inside?  For this lab, I thought something new and fun would be to dissect a bone.

skeletalsystemFrom a local butcher, I obtained a bovine leg cut down the center to see the bone interior lengthwise. With a class of students, I would also suggest about 15 discs or cross-sections (about 1″ thick) for students to dissect and observe under the dissecting microscope. I, sadly, neglected to do this.

I had the students identify the following structures:

  • Femur shaft, head, and trochanter
  • Articular cartilage
  • Compact bone
  • Spongy bone
  • Red and yellow marrow

We were also able to locate and identify skeletal muscle, tendon, and blood vessels.

Anatomy of Bones

Bones are complex structures and they differ from species to species and by location in the body. The differences are mostly in the function of the bone, but there are some things that most bones have in common.

We often think that a bone is a solid structure. However, some parts of the bone are hard while other parts are very soft. Parts will look very different when examined closely – with a magnifying lens or microscope.

The bones in your legs, and in the legs of a cow, are made of both compact bone and spongy bone.  The exteriors are walls of calcium and other minerals. This compact bone runs the length of the bone and is designed to bear loads and protect organs. The larger the animal, the thicker the compact bone. There are small channels running through the calcium to carry blood and nerves to and from the marrow, but in general, the compact bone is not very porous.

The marrows of bones are complex yet can be broadly divided in two categories, red spongy marrow and yellow marrow. At the ends of bones, you find highly porous marrow, also called red spongy marrow. Spongy marrow serves as a home to stem cells that produce blood cells. Red spongy marrow is the hard honeycomb marrow that you have likely seen in some cuts of steak because the bones are often cut open by a bandsaw. Yellow marrow is the type you find in the center of femurs and other leg bones. It is mostly fat but is edible.

The entire bone is covered by a thin covering called the periosteum, which contains blood vessels, nerves, and bone-forming cells. 

Each end of the bone is covered with a cap made of cartilage.  The cartilage covers the part of the bone where there is a joint or place where two or more bones come together. The cartilage is white in color, is slippery and smooth, and enables bones to move without rubbing together. 

Bring it Home

The “activity menu” I described last week for homework seemed to have worked really well. While those who completed only the one required activity made the same choice, there were a few who did additional (bonus) activities. They were all able to share what they learned and as a result the group was able to make connections as well as review the material. We will most assuredly be using this approach again.

Menu Choices (choose at least one):

  • Memorize the 29 major bones in the body using the handout as a guide (available to newsletter subscribers)
  • Research the myth of the Achilles tendon. How did the tendon get its name?
  • Research Andreas Vesalius. Why is he called the ‘father of anatomy’?
  • Some of the main types of joints in the body are ball-and-socket, saddle, hinge, pivot, and gliding. On a chart, describe each joint and list an example of each. Make a display of real-life objects that resemble these joints.
  • Obtain some X-rays of broken bones from a hospital or clinic. You may also find some X-ray images online. Identify the bones in the X-ray. How do doctors treat broken bones?
  • Try the Bendable Bones activity in the handout (available to newsletter subscribers).
  • Create a board game using facts about bones and muscles.
  • Write and present a skit that teaches about good care of your bones and muscles.
  • Research and present an oral report on Scoliosis.

Next week, we will explore the Muscular System in depth. My kids loved creating a fun skit to demonstrate what they learned. You won’t want to miss it.

STEM Club: Nervous System

This week, I introduced the Nervous System which consists of the brain, spinal cord, sensory organs (skin, eyes, ears, nose, and tongue), and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts.

The brain and spinal cord form the control center known as the central nervous system (CNS), where information is evaluated and decisions made. The sensory nerves and sense organs of the peripheral nervous system (PNS) monitor conditions inside and outside of the body and send this information to the CNS. Efferent nerves in the PNS carry signals from the control center to the muscles, glands, and organs to regulate their functions.

As the nervous system includes all our sensory organs, our focus activity was dissection of a cow eye. A cow eye is very similar to the eye of a human. By dissecting and examining the anatomy of a preserved cow eye, we can learn how our own eye forms images of the world around us and sends these images to our brain.
coweyedissection

Cow Eye Dissection

Distributed around the table were dissection tools and one cow eye per pair of students. I then walked them through the steps of the dissection process elaborating upon the function of each structure as we went along.

We first observed the external parts that were visible: the cornea, slera, optic nerve, as well as the fat and muscle tissue surrounding the eye.

In the cow eye, we observed four muscles that allow for the eye to move up and down and side to side. As we learned, humans have these same muscles. Humans also have ocular muscles, which allow for involuntary and voluntary eye movements that contribute to our overall vision.

We then began to look at the internal structures of the eye: vitreous humor, lens, iris, iris, ciliary body or suspensory ligaments, and tapetum.

One of the structures the kids found the most interesting was the lens. As the lens ages, it becomes more rigid and the ability to accommodate reduces. This is why as people get older; they wear bifocals or reading glasses. This condition is called presbyopia and results in difficulty seeing objects that are near.

We also observed the retina which composes the inner layer of the wall of the eye. The retina contains the photoreceptors: rods for black- and-white vision and cones for color vision. The neuron fibers coalesce at the optic disc, where they form the optic nerve exiting the posterior side (or back side) of the eye and carries impulses to the brain. The optic disc is known as the blind spot since it has no receptors.
nervoussystem

Bring it Home

At the conclusion of our lab, I gave each of the students a handout that expanded upon our discussion and included questions for review.  It included a diagram of an eye to label, a couple of activities to discover one’s blind spot, and a list of vocabulary words.  Subscribers to my newsletter will receive these in the November newsletter that will be sent next week.

I also provided a “menu” of activity choices for homework. Students are required to choose one but may do as many as they feel inclined.

Menu Choices (choose at least one):

  • There are many perception activities listed on The Exploratorium website [ http://www.exploratorium.edu/snacks/iconperception.html ]
  • Design an experiment to test the fact that different parts of the tongue are able to sense only one of four basic tastes: sweet, salty, sour, or bitter.
  • Tasting food involves more than just the taste receptors on your tongue. Smell, texture, temperature ,and look of food all contribute to how you perceive its taste. The olfactory nerve in either side of your nose sends smell information as impulses to your brain. Design an experiment to test how ones sense of smell affects their ability to taste.

Join us next week as we explore the Skeletal System.

STEM Club: Integumentary System

We began our human anatomy today with the Integumentary System – the organ system consisting of the skin, hair, nails, and exocrine glands.  The skin is only a few millimeters thick yet is by far the largest organ in the body.

Skin forms the body’s outer covering and forms a barrier to protect the body from chemicals, disease, UV light, and physical damage. Hair and nails extend from the skin to reinforce the skin and protect it from environmental damage. The exocrine glands of the integumentary system produce sweat (sudoriferous glands), oil (sebaceous glands), and wax (ceruminous glands) to cool, protect, and moisturize the skin’s surface.

skinmodels

Hair, Skin, & Exocrine Glands

We began our session with three short demonstration activities to familiarize ourselves with the organs of the integumentary system. We first observed hair under the microscope and differentiated between dog, cat, rabbit, and human hair.

Secondly, we explored our fingerprints or the images made by the tiny ridges that cover our skin on the tips of our fingers. We collected the fingerprints from each person in class and then made careful observations under a magnifying lens. I then distributed to the class a mystery print and allowed time to identify to whom it belonged.

Lastly, we talked about how our skin works to help keep our body at a constant temperature with the help of our sudoriferous or sweat glands. These glands are located deep in our skin and produce a salty liquid we call sweat. To demonstrate how these glands work, we first blew on the inside of our forearm when it was dry and then again when it was wet. As sweat reaches the surface of our skin, it evaporates or dries. As it does so, the area feels cooler as warmth is drawn away from the skin.

Somatosensation Inquiry Lab

Somatosensation, or your sense of touch, is controlled by tiny receptor cells in your skin. Because your skin is the largest organ in your body, you have millions of these receptor cells scattered throughout your body.  Somatosensative cells respond to four separate sensations: pleasure, pressure, pain, or temperature.

We did an experiment to see which parts of our skin are most sensitive:  fingertip, back of hand, palm, forearm, and back of neck. With the testing device pictured here, the kids partnered up and gently placed the two ends of the toothpicks on one of the five areas of their partner’s body. Their partner then stated whether they could feel both toothpicks or only one.

They first made a guess as to which body part would be the most sensitive (their hypothesis), numbering them in order of sensitivity. They then took turns testing one another. Their data was recorded on a table in their notebooks.
integumentaryWhen we had completed the data collection period, we gathered together to discuss the following questions:

  1. Which part of the body seems to have the least sensitivity?
  2. Which part of the body seems to have the most sensitivity? Why do you think that part of the body is the most sensitive?
  3.  Your skin is designed to help protect you from harm. Describe at least two situations in which your skin helped protect you or was trying to protect you.
  4. You’ve probably noticed that when you sit for a long period you have to shift your weight from one part of your rear to the other. You simply become uncomfortable and must move a bit. Why do you think this happens? Why do sensory cells in that part of your skin indicate too much pressure exists?
  5. What do you think people who are paralyzed from the waist down (paraplegics) must do every 20 to 30 minutes, whether they can feel anything or not? Why?

For homework, I encouraged students to continue this lab again with other family members. Alternatively, I suggested they examine other sensations, such as temperature, and design alternative methods to map out skin sensitivity levels.

Models of Skin

Additionally, I asked students to use materials they found around their house to create a model of skin (as shown in the picture at top). They were asked to label the following structures and to orally describe the function of each:

  • epidermis
  • dermis
  • fatty layer
  • fascia
  • collagen
  • hair follicles
  • oil glands
  • sweat glands / pore
  • nerves
  • blood vessels

We used the models to discuss skin pigmentation. We noted that under the top layer of skin, with its varying amounts of melanin, we are the same.

It was a great start to our anatomy cycle. Next week we will explore the nervous system in depth. The kids are very excited as we will be dissecting a bovine eye! Come join us!