Unit 06 · Digestive & Urinary Systems
Two systems share this unit because they finish the same job — turning food into usable material and clearing what the body can’t keep. The digestive tract breaks a meal down mechanically and chemically, absorbs the nutrients, and passes the rest along; the urinary system filters the blood, reclaims the water and salts worth keeping, and sends the waste out as urine. Mastery means you can trace a mouthful from teeth to bloodstream and a drop of filtrate from glomerulus to bladder — naming the structure that does each step and what would go wrong if it failed.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Digestive tract & accessory organs | Cannot name the organs of the alimentary canal in order, or confuses them with accessory organs. | Names the major organs but cannot place the accessory organs (liver, gallbladder, pancreas) or their role. | Traces the alimentary canal from mouth to anus in order and places the accessory organs that feed into it. |
| Digestion & absorption | Treats digestion as one undifferentiated process. | Separates mechanical from chemical digestion but cannot say where each nutrient is absorbed. | Distinguishes mechanical from chemical digestion and identifies where nutrients are chiefly absorbed (small intestine) and water reclaimed (large intestine). |
| Kidney & nephron structure | Cannot identify cortex, medulla, or the parts of a nephron. | Labels the kidney’s gross regions but cannot order the nephron. | Identifies cortex, medulla, and pelvis and orders the nephron from glomerulus through collecting duct. |
| Urine formation & fluid balance | Thinks the kidney simply “makes urine” with no steps. | Names filtration but not reabsorption or the kidney’s role in water balance. | Explains filtration at the glomerulus and reabsorption along the tubule, and how the kidney regulates water and salt. |
| Lab technique (specimen / slide ID) | Cannot bring a slide into focus or identify a structure on a model. | Names a structure on a model or slide but cannot point to the features that justify the call. | Identifies a structure on a model, dissection, or prepared slide and defends the ID with two visible distinguishing features. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“This is small intestine — you can see the villi projecting into the lumen, and that’s where most nutrients get absorbed. On the kidney model, the pale outer band is cortex where the glomeruli sit, and filtrate runs from there down through the tubule to the collecting duct.”
“It’s some kind of gut tube. The kidney just cleans the blood and makes pee, I think.”
You demonstrate this unit at the bench — identifying digestive and urinary structures on models, a dissection, or prepared slides, and defending each call aloud — not on a multiple-choice test. A criterion counts as mastered only when you can both find the structure and explain what it does and how it would fail. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.