WGU D313: Anatomy and Physiology II with Lab

What D313 Actually Asks of You

Anatomy and Physiology II with Lab is the second half of WGU's anatomy and physiology sequence, offered through the Leavitt School of Health and appearing in health science, pre-nursing, and related health programs. Where D312, the first course in the sequence, establishes the vocabulary, the tissues, and the framework systems, D313 turns to the systems that keep you alive minute to minute and generation to generation: cardiovascular, respiratory, digestive, urinary, reproductive, and lymphatic. WGU's own course listing describes it as a six-section, four-unit course involving laboratory activities, simulated dissections, textbook material, models, and diagrams.

Direct answer: Work through all six sections rather than skimming toward the exam, and study physiology as cause-and-effect chains instead of isolated facts — pressure drives flow, gradients drive diffusion, feedback loops correct deviations. When you can explain each system's normal function out loud without notes, and predict what changes when one variable shifts, you are ready to schedule the final assessment.

D313 is not trivia. It is the physiological reasoning behind everything you will later be asked to notice in a patient: why a low red blood cell count leaves someone exhausted, why kidney function turns up on so many lab panels, why a swollen lymph node is worth a second look. Students who treat the course as a memorization chore tend to find it grinding; students who treat it as the explanation layer under clinical practice usually move faster and retain more.

WGU publishes a useful planning anchor: if you come in with no prior background in this material, expect to spend roughly 40 to 60 hours on the course content. Those are real hours, and they are why cramming rarely works here.

The Six Systems the Course Puts in Scope

WGU's course description names the systems in scope. Each carries both structural anatomy and functional physiology, and all six are fair game:

• Cardiovascular — heart structure and the cardiac cycle, conduction and the electrical events behind it, blood composition, vessel types, blood pressure, and how flow is regulated.
• Respiratory — airway anatomy, the mechanics of ventilation, gas exchange at the alveolus, oxygen and carbon dioxide transport in blood, and the control of breathing.
• Digestive — the alimentary canal from mouth to anus, accessory organs, the chemistry of digestion, absorption, and the motility and secretion that move it all along.
• Urinary — kidney and nephron structure, filtration, reabsorption and secretion, urine formation, and the regulation of fluid, electrolyte, and acid-base balance.
• Reproductive — male and female reproductive anatomy, gamete production, the hormonal cycles that govern them, and the basics of fertilization and development.
• Lymphatic — lymphatic vessels and organs, fluid return, and the immune defenses that operate through them.

The lab side is woven through the course rather than bolted onto the end. Simulated dissections, models, and diagrams let you attach names to spatial relationships — which structure sits deep to which, which vessel feeds what. Skipping them is a false economy: much of the reasoning the assessment expects only clicks once you can picture the layout.

How Hard It Is, and How Long to Plan For

Many students describe the A&P sequence as one of the heavier science courses in a health program — not because any single concept is impossible, but because the volume is large and the systems interlock. You cannot fully understand urine formation without blood pressure, or gas exchange without hemoglobin, or swelling in the tissues without lymphatic drainage. Fall behind in one system and the next one gets harder.

Take WGU's 40 to 60 hour estimate seriously and build your calendar backward from it. At ten focused hours a week, that arithmetic lands around four to six weeks; at five hours a week, closer to eight to twelve. Students who recently finished A&P I, or who already work in a clinical setting, often move faster. Returning to science after a long gap usually means the upper end, and that is normal, not a sign you are behind.

Difficulty here is mostly a function of study method, not intelligence. Rereading the text feels productive and is one of the weakest ways to learn this material. The students who report the smoothest experience tested themselves early and often, including on material they had not "finished" yet.

A Study Plan Built for Six Interlocking Systems

Weeks 1-2 — cardiovascular and respiratory together. These two are functionally one loop, so study them as a pair. Draw the path of a red blood cell from the vena cava back out through the aorta from memory, then annotate where oxygen loads and unloads. Redraw it the next day without looking. That one exercise, repeated, beats a week of highlighting.

Week 3 — digestive. This system rewards a table you build yourself: organ, secretion, enzyme, substrate, product, and the signal that triggers it. Building the table is the learning; the finished table is only a byproduct. Then close it and reconstruct the fate of a single meal, macronutrient by macronutrient.

Week 4 — urinary and fluid balance. The nephron is where most students slow down, so give it dedicated time. Walk one filtrate molecule through each segment and state what enters, what leaves, and why. Then run scenarios: dehydration, high sodium intake, a shift in blood pH. Predicting the body's correction is exactly the kind of reasoning this material is built around.

Week 5 — reproductive and lymphatic. Reproductive physiology is heavily hormonal, so map the cycles on a timeline rather than as a list. Lymphatic is shorter but easy to underestimate; connect it back to capillary fluid dynamics from your cardiovascular work so it does not float free.

Week 6 — retrieval and integration. Stop consuming new material. Use spaced repetition on your weakest terms, and spend most of your time on mixed-topic self-testing so you have to identify which system a question belongs to before you answer it. Use the course's own practice and pre-assessment tools, and treat every wrong answer as an assignment: write one sentence explaining why the correct answer is correct before moving on.

Throughout, teach out loud. Explaining the cardiac cycle to an empty room or a study partner exposes gaps that silent reading hides. The same rhythm carries into the courses built on this one, including D236 Pathophysiology, where normal function becomes the baseline you measure disease against.

Where D313 Students Lose Ground

• Memorizing names without mechanisms. Knowing that the loop of Henle exists is not the same as knowing what it accomplishes. Questions that ask you to predict an outcome punish name-only study.
• Skipping the lab activities. The simulated dissections and models build the spatial sense that makes structural questions feel obvious instead of arbitrary.
• Studying each system in a sealed box. Blood pressure shows up in the kidney material; hemoglobin shows up in the respiratory material. The cross-links are where the harder reasoning lives.
• Treating a pre-assessment as a practice exam to be beaten. Its value is diagnostic. Use it to find weak areas and then go back to the course material, rather than trying to memorize the items themselves.
• Relying on third-party "answer" bundles. Beyond the academic integrity problem, they train recognition of specific wording rather than understanding, and that collapses under any rephrasing.
• Letting the gap since A&P I go unaddressed. If cell transport, tissue types, or basic homeostasis feel fuzzy, spend two hours refreshing them before you start.
• Scheduling by calendar rather than by evidence. Book the assessment when your self-testing across all six systems is consistently solid, not because a term date is approaching.

D313 Readiness Checklist

• Can you trace blood through both circuits from memory and say where gas exchange occurs in each?
• Can you explain how ventilation is mechanically produced and how the body adjusts breathing rate?
• Can you describe what happens to a mixed meal in each digestive organ, including which secretions act on it?
• Can you walk a filtrate through every nephron segment and explain filtration, reabsorption, and secretion?
• Can you predict how the body responds to dehydration or an acid-base disturbance, and name the systems involved?
• Can you outline the hormonal control of the reproductive cycles without consulting a diagram?
• Can you explain how lymphatic vessels return fluid and how that connects to capillary pressure?
• Have you actually completed the lab activities and simulated dissections rather than skimming them?
• Are you scoring consistently well on mixed-topic self-tests that pull from all six systems at once?

D313 FAQ

Is D313 an OA or a PA?

WGU's course description points to a single final assessment covering the course competencies, and the laboratory work is built into the course of study rather than submitted as a separate written performance task — so plan for an objective assessment. Because WGU revises course versions, confirm the exact structure and proctoring requirements on your own Course of Study page before you plan your final weeks.

How many competency units is D313 worth?

Four. WGU's listing describes Anatomy and Physiology II with Lab as a six-section, four-unit course, and WGU's institutional catalog records D313 at four competency units.

How long does D313 usually take?

WGU states that students with no prior knowledge of the material can expect to spend roughly 40 to 60 hours on the course content. At ten focused hours a week that works out to about four to six weeks, and at five hours a week to roughly eight to twelve. A slower pace is completely reasonable if the material is new to you.

Do I need to finish Anatomy and Physiology I first?

Programs generally sequence D313 after the first A&P course, and the content assumes that foundation. Even if your program allows a different order, refresh cell transport, tissue types, and homeostatic feedback before you start — nearly every system in D313 leans on them.

Is the lab component hands-on or virtual?

WGU describes the course as involving laboratory activities, simulated dissections, models, and diagrams delivered through the course materials. Check your Course of Study for anything your program adds.

What is the best single study technique for this course?

Retrieval practice with spaced repetition. Close the book, reconstruct a diagram or a process from memory, check it, correct it, and revisit it a few days later. It feels harder than rereading, and that difficulty is exactly why it works.

Where D313 Takes You Next

D313 is where anatomy stops being a list and starts being an explanation. Get it right and the coursework that follows — D236 Pathophysiology and hands-on work such as D445 Intermediate Nursing Skills — has something solid to stand on. Browse more health guides on our Leavitt School of Health hub, or see every course in the full guide index. Official course details are always on WGU's program page.

This is an independent study guide. It is not affiliated with, endorsed by, or produced by Western Governors University, and it contains no exam content.