Guide
Unit summaries, comparison tables, common mistakes and check-yourself questions with answers
Unit 1: Body Organization, Terminology and Homeostasis
Key Concepts
• Levels of organization: chemical, cellular, tissue, organ, organ system, organism.
• Anatomical position: standing upright, facing forward, arms at sides, palms forward, feet forward.
• Directional terms: superior/inferior, anterior (ventral)/posterior (dorsal), medial/lateral, proximal/distal
(limbs, relative to the trunk), superficial/deep.
• Planes: sagittal (left and right; midsagittal = equal halves), frontal/coronal (anterior and posterior),
transverse (superior and inferior).
• Body cavities: dorsal (cranial, vertebral) and ventral (thoracic: pleural, pericardial, mediastinum;
abdominopelvic). Abdominal quadrants: RUQ, LUQ, RLQ, LLQ.
• Homeostasis: a stable internal environment maintained mostly by negative feedback (response
reverses the change: temperature, blood glucose, blood pressure). Positive feedback amplifies the
change until an event ends (childbirth contractions with oxytocin, blood clotting).
At a Glance
Term Meaning Example
Proximal Closer to the trunk/attachment Elbow is proximal to the wrist
Distal Farther from the trunk/attachment Fingers are distal to the wrist
Medial Toward the midline Nose is medial to the eyes
Lateral Away from the midline Ears are lateral to the eyes
Superficial Toward the body surface Skin is superficial to muscle
Deep Away from the surface Bone is deep to muscle
Common Mistakes
• Using proximal/distal for the trunk (use superior/inferior there).
• Calling childbirth an example of negative feedback (it is positive).
Check Yourself
Which plane divides the body into anterior and posterior parts?
Answer: The frontal (coronal) plane.
Body temperature rises and sweating begins, lowering it. What type of feedback?
Answer: Negative feedback.
, Unit 2: Basic Chemistry and Cell Biology
Key Concepts
• Key molecules: carbohydrates (energy), lipids (energy storage, membranes, hormones), proteins
(enzymes, structure, transport), nucleic acids (DNA, RNA). ATP is the cell's energy currency.
• Organelles: plasma membrane (selectively permeable phospholipid bilayer), nucleus (DNA),
mitochondria (ATP via aerobic respiration), ribosomes (protein synthesis), rough ER (protein
processing), smooth ER (lipids, detoxification), Golgi (packaging), lysosomes (digestion).
• Passive transport (no ATP): diffusion, facilitated diffusion, osmosis (water moves toward higher solute
concentration). Active transport (ATP): sodium-potassium pump (3 Na+ out, 2 K+ in), endocytosis,
exocytosis.
• Tonicity: isotonic (e.g., 0.9% NaCl; no net change), hypotonic (cells swell and may burst), hypertonic
(cells shrink).
• Cell division: mitosis (growth and repair; identical diploid cells) and meiosis (gametes; haploid cells).
At a Glance
Organelle Function
Mitochondria Produce ATP
Ribosomes Build proteins
Rough ER Process proteins
Smooth ER Make lipids, detoxify
Golgi apparatus Modify and package proteins
Lysosomes Break down waste and worn-out parts
Common Mistakes
• Saying water moves toward lower solute concentration (it moves toward higher).
• Thinking facilitated diffusion uses ATP.
Check Yourself
A red blood cell placed in distilled water will do what?
Answer: Swell and may burst (hypotonic solution).
Which organelle makes most of the cell's ATP?
Answer: Mitochondria.