Studying Structures, Diagrams and Processes

A&P asks you to learn two very different things: the parts of the body and the processes that make those parts work. Each one needs its own study tools. This chapter shows you how to learn a structure so it sticks, how to practice with diagrams and models, and how to turn a long process into a story you can tell from memory.

Two kinds of A&P knowledge

Look at any OpenStax chapter in BIO 243 and you will find two kinds of content mixed together.

Structures are the "what" and "where" of the body. The parts of a long bone. The layers of the epidermis. The lobes of the cerebrum. The twelve cranial nerves. Learning structures is a lot like learning a map: names, locations, and what sits next to what.

Processes are the "how" and "why." How a bone grows in length. How a muscle fiber contracts. How a neuron fires an action potential. How the sympathetic nervous system speeds up your heart. Learning a process is like learning a recipe or the plot of a movie: steps in order, where each step causes the next.

Many students use one method for everything, usually reading and flashcards. Flashcards are great for names, but they chop a process into separate facts, and you lose the order and the cause. Long reading sessions can explain a process, but they do not train you to find structures on a model or a slide. The rest of this chapter gives you a tool kit for each kind, and they all build on the strategies from Chapter 6: retrieval practice, spacing, elaboration and dual coding.

This chapter belongs to week 7 for a reason. Around then you are deep in Chapter 10, muscle tissue, which holds one of the longest processes in the course, and just ahead are nervous tissue and the central nervous system, which are full of both structures and processes. Getting your methods right now pays off through Exam 3 and the final.

Learning a structure: the four questions

When you meet a new structure, do not just memorize its name. Ask four questions about it. Each answer gives your memory another hook to hang the name on.

1. Where is it? Use the directional terms from Chapter 1: superior and inferior, medial and lateral, proximal and distal, anterior and posterior. "Somewhere in the arm" is not enough. "The lateral bone of the forearm" is.
2. What are its neighbors? What does it touch, connect to, or sit beside? Anatomy is a neighborhood. If you know the neighbors, you can find the house.
3. What does it do? Function is the strongest hook of all, because it gives the structure a reason to exist. A structure with a job is much easier to remember than a word with a location.
4. What does its name mean? Most anatomical names are Latin or Greek descriptions. Once you decode the name, it often tells you the shape, the location, or the job.

Notice what happened in Figure 7.1. Your BIO 243 chapters do not cover the radius in detail (that is mostly Chapter 8 in OpenStax, the appendicular skeleton, and BIO 243 touches it through joints in Chapter 9). But the method works on anything. Try it on a muscle name you meet in lab: the sternocleidomastoid. The name looks terrifying until you split it. Sterno means sternum, cleido means clavicle, and mastoid means the mastoid process of the temporal bone, the bump behind your ear. The name is a map: the muscle runs from the sternum and clavicle up to the mastoid process. Its job is to turn and flex the head. And here is a bonus neighbor: it is controlled by cranial nerve XI, the accessory nerve, which you will meet in Chapter 13.

Word parts do a lot of the work

Chapter 3 suggested keeping a running vocabulary list with word roots. In anatomy, those roots pay off constantly. A few that run through Exam 2:

• osteo- means bone. chondro- means cartilage. myo- or sarco- means muscle.
• -blast means a building or growing cell. -clast means a breaking cell. -cyte means a mature cell.
• Put them together: an osteoblast builds bone, an osteoclast breaks bone down, and an osteocyte is a mature bone cell maintaining the matrix. A chondrocyte is a mature cartilage cell.
• epi- means upon or above, dia- means through or across, and peri- means around. So the periosteum is the membrane around the bone, and the epiphysis sits on the end of the long bone's shaft, the diaphysis.

Blank-diagram practice

A&P figures carry a huge amount of the content. The single best way to learn a labeled figure is not to stare at it. It is to cover the labels and try to fill them in. That is retrieval practice applied to pictures.

How to make a blank diagram

• Cover the labels on the OpenStax figure with small sticky notes or strips of paper.
• Screenshot the figure and draw white boxes over the labels with any photo or drawing app.
• Print the figure and use correction tape over the labels.
• Use the unlabeled images and virtual labs on Dr. Garg's free BIO 243 study-tools site.

Climb the ladder

Do not stop at one level. Move up a ladder of difficulty as the easy level starts to feel easy:

1. Label with a word bank. Write the terms in a list on the side, then match them to the blanks. This is the starting point, good for the first day.
2. Label with no word bank. Now you must produce every name yourself, and spell it. Exams and practicals will not give you a list.
3. Draw it from scratch. A blank page, no figure. Sketch the structure and label it. Your drawing can be rough; the labels and their positions are what count.
4. Explain it. Point to each part and say what it does. Now you are linking structure to function, which is what higher-level exam questions ask for.

After each attempt, check against the real figure and mark your misses in a different color. Return to the same diagram a day or two later. The misses you circled are your first target. That is spacing, built right in.

Models, slides and lab practicals

Lab is part of your BIO 243 grade, and lab asks you to find structures on real objects: plastic models, bones, microscope slides and images. That is harder than finding them on a clean textbook figure, for a few reasons. A model may be a different color than the book. It may be turned around, cut at a different angle, or show the left side when you studied the right. A microscope slide never looks quite like the photo in the book.

A few habits help a lot:

• Study from more than one view. If you only ever see a femur from the front, a back view will throw you. Rotate the model. Look at the bone from every side.
• Learn features, not pictures. Instead of memorizing what one image looks like, learn the features that identify a structure. Then you can recognize it from any angle.
• Use your own body. You carry a skeleton everywhere. Feel the olecranon of your ulna (the point of your elbow), the mastoid process behind your ear, the spine of your scapula, and the medial and lateral malleoli at your ankle. Bend and turn your joints and name the movement: flexion, extension, abduction, adduction, rotation, supination, pronation.
• Practice under practical-like conditions. If your lab uses timed practicals, practice the same way. Have a friend point to structures and give you a short time to name each one, or use a timed quiz on the study-tools site.
• Use open lab time and virtual labs. Seeing the model more than once, on more than one day, beats one long session the night before.

Processes as stories

Processes are where many BIO 243 students lose the most points. The usual mistake is to memorize a process as a list of separate facts. "Calcium. Troponin. Tropomyosin. Myosin. ATP." Each word is right, but under exam pressure the list falls apart, because nothing holds the pieces in order.

The fix is to learn a process as a story: a series of steps where each step happens because of the one before it. A story has a beginning, an order, and causes. If you know why step 4 happens, you cannot forget that step 3 came first. When you write a process out, put the word "so" or "because" between every step. If you cannot fill in the "because," you have found the part you do not understand yet.

The muscle contraction story

Here is excitation-contraction coupling and the sliding filament model from Chapter 10, told as one story. Figure 7.2 shows the same story as a flow chart.

Now read it as a story with "because" links. A signal comes down the motor neuron, so the axon terminal releases acetylcholine. Acetylcholine binds to receptors on the muscle fiber, so sodium rushes in and starts an action potential in the muscle cell. That action potential races along the sarcolemma and dives deep into the fiber through the T-tubules, so the sarcoplasmic reticulum lets go of its stored calcium. Calcium binds to troponin, so tropomyosin is pulled off the binding sites on actin. Now the myosin heads, already cocked by splitting ATP, can grab actin and pull, so the thin filaments slide toward the center of the sarcomere. A new ATP binds each myosin head so it can let go, re-cock, and grab again. As long as calcium and ATP are there, the cycle repeats.

Once you have the story, you can answer the "what if" questions that exams love, because you can reason through them instead of hoping you memorized them:

• What if acetylcholinesterase is blocked? ACh is not cleared from the synapse, so the muscle keeps getting stimulated and has trouble relaxing.
• What if there is no ATP, as after death? Myosin heads cannot detach from actin, so the muscle stays locked. That is rigor mortis.
• What if calcium stays in the sarcoplasm? Troponin keeps tropomyosin pulled aside, so cross-bridges keep forming and the muscle stays contracted.
• What happens to the bands of the sarcomere? The Z discs move closer together, so the I band and H zone shrink, but the A band, which is the length of the thick filaments, stays the same.

The action potential story

The action potential in Chapter 12 is the other great process of the course, and it shows up again in muscle, in the senses, and in the autonomic nervous system. It is easiest to learn as a story told along a graph, because the graph shows you the membrane voltage at each moment.

Tell it with "because" links. At rest, the inside of the neuron sits around -70 millivolts. A stimulus nudges it upward. If it reaches threshold, about -55 mV, voltage-gated sodium channels open, so sodium rushes in, because there is much more sodium outside the cell and the inside is negative. That inrush makes the inside positive, up to about +30 mV. At the peak, the sodium channels inactivate and voltage-gated potassium channels open, so potassium flows out and the voltage falls back down. The potassium channels are slow to close, so the voltage briefly dips below resting, which is called hyperpolarization. Then the cell settles back to rest, while the sodium-potassium pump keeps the gradients in place over the long run.

The muscle story and the neuron story connect. Step 1 of Figure 7.2 is the whole of Figure 7.3, arriving at an axon terminal. When you see that link, two big topics become one bigger, easier-to-remember story.

Drawing from memory

You do not have to be an artist to learn by drawing. Researchers have found that drawing a word or idea tends to improve later memory for it compared with simply writing it out, an effect Jeffrey Wammes and his colleagues (2016) called the drawing effect. A review by Peggy Van Meter and Joanna Garner (2005) found that drawing your own diagrams while you learn can help, especially when you get some guidance on what to draw and then check your drawing against an accurate source. In other words, drawing works best as retrieval plus feedback, not as decoration.

Some drawings worth doing from memory in BIO 243:

• A long bone with diaphysis, epiphyses, articular cartilage, periosteum, endosteum, medullary cavity, and epiphyseal plate or line.
• An osteon with its central canal, rings of lamellae, lacunae holding osteocytes, and canaliculi linking them.
• A synovial joint with the articular capsule, synovial membrane, joint cavity filled with synovial fluid, and articular cartilage.
• A sarcomere, relaxed and contracted, side by side, with Z discs, M line, thick and thin filaments, A band, I band and H zone.
• A neuron with dendrites, cell body, axon hillock, axon, myelin sheath, nodes of Ranvier and axon terminals, plus an arrow showing which way the signal travels.
• A chemical synapse, showing the presynaptic terminal, vesicles, cleft, receptors on the postsynaptic cell, and the steps in order.

Keep your drawings simple: boxes, circles and lines. Time yourself. A two-minute sketch from memory, checked against the book, is worth more than a twenty-minute copy of the figure.

Mnemonics: use them sparingly and correctly

A mnemonic is a memory trick, often a sentence where each word starts with the same letter as an item on a list. Mnemonics can be useful in A&P for one specific job: remembering a list with a fixed order that has no built-in logic. They are much less useful for understanding. The Dunlosky (2013) review rated the keyword mnemonic, one common type, as having low overall usefulness, partly because the memories it builds can fade quickly and because it works for some kinds of material much better than others.

The classic A&P case is the twelve pairs of cranial nerves in Chapter 13. They are numbered in Roman numerals, roughly from front to back along the brain, and the exam will expect you to know the name, number and job of each one.

Two common mnemonics are at the bottom of Figure 7.4. The first word of each gives you the first letter of each nerve in order: Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal. The second gives you the type of each nerve in order: sensory, sensory, motor, motor, both, and so on.

Rules for using mnemonics well

• Use them for order, not for meaning. The mnemonic tells you the seventh nerve starts with F. It does not tell you that the facial nerve controls the muscles of facial expression and carries taste from the front of the tongue. Learn the jobs with the four questions and with stories.
• Know which "O" or "T" is which. Three nerves start with O and two with T. Practice saying the full names, not just the letters.
• Pair them with meaning when you can. The abducens nerve (VI) moves the eye laterally, which is abduction, away from the midline. The name and the job match. The hypoglossal nerve (XII) runs below (hypo) the tongue (glossal) and moves it.
• Keep them few. A handful of mnemonics for true lists is helpful. Fifty mnemonics for everything becomes its own memory burden.
• Keep them clean. Some A&P mnemonics passed around online are crude. Make your own instead. A mnemonic you invented is usually easier to remember anyway.

Your structure and process toolkit

When you sit down to study, first ask: is this a structure or a process? Then pick the tool.

• For a structure: answer the four questions, decode the name, practice blank diagrams up the ladder, find it on a model or on your own body, and draw it from memory.
• For a process: write it as a story with "so" and "because" between steps, draw it as a flow chart or a graph, ask "what if" questions, and tell it out loud without notes.
• For a true ordered list: use a mnemonic, then attach meaning to every item.

All of these are forms of the strategies from Chapter 6. Blank diagrams are retrieval practice. Coming back to the same diagram after two days is spacing. "Because" links are elaboration. Drawing is dual coding. You are not learning a new set of tricks. You are using the same strong strategies in the shapes that A&P content comes in. Chapter 8, Plan Backward, will show you how to fit all of this into the days before an exam.