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Week 16 · Final study guide

Final Exam — Study Guide

Human Anatomy and Physiology I Free sample edition

Coverage — what the final covers

The final is cumulative: its questions reach all eight course objectives, across the fifteen teaching weeks. It is given in Week 16, the finals week, which has no new material. The exam has 40 questions, and every question counts the same. Thirty-one are multiple choice with one best answer, four ask you to select every choice that fits, and five are true/false statements. There is no time limit, and you get one attempt. It opens in Week 16, in Canvas, when your instructor sets it to open.

The questions were drawn from the course's question bank, and every objective appears at least once. The draw sits entirely in the second half of the term. Here is what this form actually contains:

The final's 40 questions by the week whose material each question comes from, with the objectives those questions assess
Week Topic Questions Objectives assessed
9 The skeleton and joints 6 Objective 4 (6)
10 Muscle tissue and the physiology of contraction 6 Objective 5 (6)
11 The muscular system 6 Objective 5 (5), Objective 4 (1)
12 Nervous tissue, the neuron, and the action potential 7 Objective 6 (6), Objective 2 (1)
13 The central nervous system 4 Objective 7 (3), Objective 3 (1)
14 The peripheral and autonomic nervous system 5 Objective 7 (3), Objective 1 (2)
15 The special senses 6 Objective 8 (5), Objective 3 (1)
The final's eight objectives, the weeks that teach each one, and the number of the exam's 40 questions on each
Objective What you do Weeks Questions on this exam
Objective 1 Use the language of the body and trace a homeostatic feedback loop 1 2
Objective 2 Relate the body's chemistry to its function and explain the cell, its transport, its energy, and protein synthesis 2, 3, 4 1
Objective 3 Identify the tissue types and describe the integumentary system 5, 6 2
Objective 4 Describe bone as a living tissue, sort the skeleton, and classify joints 7, 9 7
Objective 5 Explain muscle structure, the order of contraction, and the muscular system 10, 11 11
Objective 6 Describe neurons and neuroglia and explain the nerve impulse 12 6
Objective 7 Describe the central, peripheral, and autonomic nervous system 13, 14 6
Objective 8 Trace each special sense from its stimulus to its receptor 15 5

That is all 40 questions from Weeks 9–15, and each question assesses exactly one objective. Muscle (11 questions) and the nervous system (12 questions between Objective 6 and Objective 7) carry 23 of the 40, so put most of your review there, and Week 12 alone carries 7. The Weeks 1–7 ideas still earn their place: twelve questions assess Objective 1 through Objective 4, six of them inside Weeks 11–15 material, and structure determines function runs through nearly everything.

Topic-by-topic review

Each unit gives the idea in plain words first, then the course's exact definitions, then the mistakes students make most often and the cure for each. The "deeper review" line tells you where to look in that week's materials. Units 6–12 carry the weight of the exam, so they get the most space.

Unit 1 — The language of the body and homeostasis (Weeks 1 and 8)

  • Key idea. Before you can say where anything is, the body has to stand in one agreed pose, and before you can say how it stays alive, you need the loop that holds it steady.
  • Two views of one thing. Anatomy is the study of the body's structures: what the parts are, how each one is built, and where it sits. Physiology is the study of how the body's parts work, alone and together, to keep a person alive. The course reads every structure in one order: structure, then function, then the clinical connection.
  • The ladder. The levels of structural organization, smallest to largest: chemical, cellular, tissue, organ, organ system, and organism. A new ability appears at each step: a heart cell twitches, but only the organ pumps.
  • The loop. Homeostasis is the maintenance of a stable internal environment. The set point is the target value a regulated variable is held near, about 37 °C for body temperature. Every loop runs receptor → control center → effector: the receptor senses and reports, the control center compares the report with the set point, and the effector acts to change the variable. Negative feedback reverses a change and runs most of physiology. Positive feedback intensifies a change until an end event stops it, as in childbirth or blood clotting. The names mean direction, not good or bad.
  • The pose and the pairs. The anatomical position is standing upright, feet parallel and about shoulder-width apart, upper limbs at the sides, and palms facing forward, so the thumb is lateral. The pairs are superior/inferior, anterior/posterior, medial/lateral, proximal/distal (limbs only), and superficial/deep, and every statement names the two structures compared. Left and right are always the body's own.
  • The planes. A sagittal plane makes left and right parts, a frontal plane makes front and back parts, and a transverse plane makes top and bottom parts, a cross-section.
  • The three-step read (Week 8). For any structure, name it and where it sits, state its function and how its shape makes that possible, then name one clinical connection in standard terms and stop.
  • Predictable mistakes → cures. Calling negative feedback bad: it means the response reverses the change. Letting the control center sense: the receptor senses, the control center compares. Calling the thumb medial: stand the body in the anatomical position first. Using proximal for the trunk: proximal and distal are for limbs.
  • Deeper review: the Week 1 chapter and slides, and the Week 8 review module.

Unit 2 — Chemistry and the cell (Weeks 2 and 3)

  • Key idea. The body is chemistry in water, and every cell guards its border, deciding what crosses and which way the water goes.
  • Bonds. In an ionic bond one atom transfers an electron to another and the two oppositely charged ions attract. In a covalent bond two atoms share one or more pairs of electrons; inside a water molecule the sharing is uneven, a polar covalent bond. A hydrogen bond is a weak attraction between a slightly positive hydrogen on one molecule and an electronegative atom on a neighboring molecule.
  • pH. pH measures hydrogen-ion concentration on an inverse logarithmic scale from 0 to 14, with 7 neutral and each whole unit a tenfold change. Count the steps, then raise ten to that power: pH 4 against pH 7 is three steps, so 10³ = 1,000 times more hydrogen ions. Blood is defended between 7.35 and 7.45. A buffer resists a change in pH; below the range is acidosis, above it alkalosis.
  • The four organic classes. Carbohydrates are built from monosaccharides, proteins from amino acids, and nucleic acids from nucleotides. A lipid such as a triglyceride is not built from one single repeating building block. Denaturation unfolds a protein's shape and can cost it its function.
  • The membrane. The plasma membrane is a phospholipid bilayer studded with proteins, and it is selectively permeable. The organelles pair with their jobs: the ribosome builds proteins, the rough ER makes proteins for the membrane or export, the smooth ER makes phospholipids and steroid hormones, the Golgi apparatus modifies, sorts, and ships, the lysosome breaks down worn-out parts, and the mitochondrion converts the energy in nutrients into ATP.
  • Crossing the border. Passive transport runs from higher to lower concentration and costs no ATP: diffusion, facilitated diffusion, and osmosis, the diffusion of water toward the side with more solute. Read tonicity from the cell's side against the model cell's 300 mOsm/L: a hypotonic bath has less solute, water moves in, and the cell swells; a hypertonic bath has more, water moves out, and the cell shrinks; an isotonic bath has the same, with no net movement. Active transport runs against the gradient and is paid for with ATP; the sodium-potassium pump moves 3 Na⁺ out and 2 K⁺ in per ATP.
  • Predictable mistakes → cures. "pH 4 is three times more acidic than pH 7": it is 1,000 times. "Two units is twentyfold": it is 100. "Osmosis moves the salt": it moves water. Flipping hypotonic and hypertonic: always compare from the cell's side. Writing the pump as 2 out and 3 in: it is 3 Na⁺ out, 2 K⁺ in.
  • Deeper review: the Week 2 and Week 3 chapters and the tonicity table; Week 12 brings the pump back.

Unit 3 — Cellular energy and protein synthesis (Week 4)

  • Key idea. A cell spends ATP like cash and remakes it from food, and it builds every protein by copying a gene and reading the copy.
  • ATP. ATP releases usable energy when one phosphate group is split off, leaving ADP; energy from food adds the phosphate back.
  • Cellular respiration, in order and in place. Glycolysis (cytoplasm) → citric acid cycle, also called the Krebs cycle (mitochondrial matrix) → electron transport chain (inner mitochondrial membrane). Glycolysis splits one glucose into two pyruvate, spends two ATP and makes four for a net gain of two, and needs no oxygen. The chain makes the most ATP, and oxygen is the final electron acceptor, forming water. When oxygen is short, pyruvate is converted to lactic acid so glycolysis can keep running. The total ATP per glucose is taught in words: the older theoretical estimate is about 36, and current estimates are nearer 30 to 32, because the yield depends on conditions in the cell.
  • Gene to protein, in order and in place. A gene is a functional segment of DNA that carries the information to build a protein. Transcription writes a complementary mRNA in the nucleus, with uracil in place of thymine. Translation reads the mRNA at a ribosome, one codon of three bases at a time. AUG is the start codon for methionine, and UAA, UAG, and UGA are stops. The course's gene reads Met–Ala–His–Lys–Gly, then stop: six codons, five amino acids.
  • Predictable mistakes → cures. Crediting glycolysis with the most ATP: the chain makes the most. Placing the citric acid cycle in the cytoplasm: it runs in the matrix. "Oxygen is broken down for energy": it accepts electrons and forms water. Writing a T into an mRNA: RNA uses U.
  • Deeper review: the Week 4 chapter and the Decode the Gene lab.

Unit 4 — Tissues and the skin (Weeks 5 and 6)

  • Key idea. Every organ is a mix of four fabrics, and the skin is the first one you meet whole.
  • The four tissue types and their verbs. Epithelial tissue covers and lines, as sheets of tightly packed cells. Connective tissue supports, binds, and protects, as cells scattered through a matrix they make themselves. Muscle tissue contracts to produce movement. Nervous tissue communicates by electrochemical signals, with neurons among smaller neuroglia. Blood is a fluid connective tissue whose matrix is the plasma.
  • Epithelium by name. Layers first, shape second: simple is one layer and stratified is stacked; squamous, cuboidal, and columnar are shapes, never counts. Epithelium is avascular, fed by diffusion from below. Simple squamous lines the air sacs, the shortest diffusion path.
  • The skin. The epidermis is keratinized stratified squamous epithelium with no blood vessels of its own. Its strata run deep to superficial: basale, spinosum, granulosum, lucidum (thick skin only), and corneum, four layers in thin skin and five in thick. Keratin gives toughness and water resistance; melanin colors skin and absorbs ultraviolet light. The dermis is the vascular connective-tissue layer beneath, and the hypodermis below it is usually not counted as skin.
  • Thermoregulation is the Week 1 loop on the skin. Too warm: eccrine sweat evaporates and dermal arterioles dilate. Too cold: arterioles constrict, sweating stops, and the arrector pili raise goosebumps.
  • Predictable mistakes → cures. "Blood is a muscle": it is a connective tissue with a fluid matrix. Reading squamous as a layer count: it is a shape. Calling the epidermis vascular: it has no vessels. "Sweating warms you": evaporation cools.
  • Deeper review: the Week 5 and Week 6 chapters; Week 13 brings nervous tissue back as gray and white matter, and Week 15 brings the skin's senses back as receptor classes.

Unit 5 — Bone tissue (Week 7)

  • Key idea. Bone is alive: it has vessels, nerves, and cells, and it rebuilds itself for life.
  • The long bone. The diaphysis is the tubular shaft, with compact walls around the medullary cavity, which holds yellow marrow. Each epiphysis is a wider end filled with spongy bone. The epiphyseal plate is hyaline cartilage where a growing bone lengthens. The periosteum covers the outside, and the endosteum lines the cavity.
  • Compact and spongy. Compact bone is built from osteons, concentric lamellae around a central canal. Spongy bone is a lattice of trabeculae with red marrow in the spaces, and it has no osteons.
  • The cells. Osteoblasts build new bone, osteocytes maintain the matrix, and osteoclasts resorb bone and release calcium. Blast builds, clast resorbs. Remodeling is the lifelong cycle of the two, shaped by mechanical stress.
  • The calcium loop. Parathyroid hormone raises blood calcium by stimulating osteoclasts; calcitonin lowers it by inhibiting osteoclasts.
  • Predictable mistakes → cures. "Bone is dead mineral": it is living connective tissue. Swapping osteoblast and osteoclast. Calling the epiphysis the shaft. Giving spongy bone osteons.
  • Deeper review: the Week 7 chapter and the Build a Bone lab.

Unit 6 — The skeleton and joints (Week 9)

  • Key idea. Every bone sorts into one of two divisions, and every joint trades some stability for some movement.
  • Two divisions. The axial skeleton runs along the body's central axis: the skull, the hyoid and the ear ossicles, the vertebral column, and the thoracic cage, 80 bones in an adult. The appendicular skeleton is the upper and lower limbs and the girdles that attach them, 126 bones. The girdles are appendicular: if it attaches a limb, it is appendicular.
  • The counts, from the course. 80 = 22 skull + 7 associated (1 hyoid + 6 ossicles) + 26 vertebral column + 25 thoracic cage. The column is 7 cervical, 12 thoracic, and 5 lumbar vertebrae, 24 in all, plus the sacrum and the coccyx. The thoracic cage is 12 pairs of ribs, 24 ribs, plus the sternum; ribs 1 to 7 are true, 8 to 12 are false, and 11 and 12 also float. Each limb has 30 bones, and 4 × 30 = 120, so 126 − 120 = 6 girdle bones.
  • Read from the anatomical position. The radius is the forearm bone on the lateral, thumb side; the ulna is medial. The tibia is the medial bone of the leg and carries the body's weight; the fibula is lateral and does not. The femur is the longest and strongest bone.
  • Joints by structure and by function. A fibrous joint is held by fibrous connective tissue with no cavity, such as a skull suture. A cartilaginous joint is held by hyaline cartilage or fibrocartilage with no cavity, such as an intervertebral disc. In a synovial joint the bone ends meet inside a fluid-filled joint cavity. By function, a synarthrosis is immovable, an amphiarthrosis allows limited movement, and a diarthrosis moves freely. Every synovial joint is a diarthrosis.
  • The synovial joint's parts. Articular cartilage on each bone end, the joint cavity, the articular capsule, the synovial membrane that secretes the synovial fluid, and the ligaments.
  • The six synovial types. Pivot (the atlantoaxial joint), hinge (the elbow), condyloid (the wrist), saddle (the base of the thumb), plane (between carpals or tarsals), and ball-and-socket (the hip and the shoulder, the only two, with the widest range of motion).
  • The movement pairs. Flexion decreases the angle between the bones and extension increases it. Abduction moves a limb away from the midline and adduction toward it. Rotation, circumduction, plantar flexion and dorsiflexion, and pronation and supination complete the set.
  • Mobility against stability. A shallow socket gives the shoulder its wide range at the cost of easy dislocation, while the deep socket of the hip bears the weight of the body.
  • Predictable mistakes → cures. Calling the scapula or the hip bones axial: they attach limbs. Writing "12 cervical, 7 thoracic": it is 7-12-5. Putting the ulna on the thumb side: the radius is. Making the fibula the weight-bearer: the tibia is. Calling a suture synovial: it is fibrous, immovable, and has no cavity. "The cartilage makes the synovial fluid": the synovial membrane does. Confusing flexion with abduction: flexion changes an angle, abduction moves away from the midline.
  • Deeper review: the Week 9 chapter, the skeleton-count table, and the Build the Skeleton, Name the Joints lab.

Unit 7 — Muscle tissue and the physiology of contraction (Week 10)

  • Key idea. A nerve signal becomes a pull in one fixed order, and the filaments slide rather than shrink.
  • The hierarchy. Muscle → fascicle → muscle fiber → myofibril → sarcomere, wrapped by the epimysium, perimysium, and endomysium. A muscle fiber is one skeletal muscle cell, long and with many nuclei; its membrane is the sarcolemma.
  • The sarcomere. The sarcomere is the functional unit, from one Z disc to the next. Thin filaments of actin anchor to the Z discs and carry the regulatory proteins troponin and tropomyosin. Thick filaments of myosin sit in the middle and carry the heads. The T-tubules carry the muscle action potential inward, and the sarcoplasmic reticulum stores, releases, and takes back Ca²⁺.
  • The sliding filament model, taught as a model. The thin filaments are pulled past the thick filaments, the Z discs move closer, and the sarcomere shortens while the A band keeps its width, because neither filament gets shorter.
  • Excitation-contraction coupling, in order. ACh at the neuromuscular junction → muscle action potential along the sarcolemma and down the T-tubules → Ca²⁺ from the sarcoplasmic reticulum → Ca²⁺ binds troponin, and tropomyosin uncovers actin → cross-bridge and power stroke (ATP). Acetylcholine is the chemical messenger the motor neuron releases at the neuromuscular junction.
  • ATP's three jobs. ATP powers the power stroke, releases the myosin head from actin, and pumps Ca²⁺ back. Without ATP the heads stay locked, as in rigor mortis. Relaxation is an ordered, ATP-costing shutdown: the motor neuron stops, ACh is broken down, Ca²⁺ is pumped back into the sarcoplasmic reticulum, and tropomyosin covers actin again.
  • Motor units and fiber types. A motor unit is one motor neuron plus every muscle fiber it supplies; small motor units give fine control. Slow oxidative fibers are rich in mitochondria, capillaries, and myoglobin and resist fatigue; fast glycolytic fibers store much glycogen and contract quickly and powerfully but tire fast.
  • Fatigue. A fall in a muscle's ability to keep contracting, reflecting ATP running low, lactic acid lowering the pH inside the fiber, and ion imbalances. The course's grip series, 24, 21, 18, 15, and 12 squeezes, averages 18 and declines 50%: fewer cross-bridges cycle, and the filaments never shorten.
  • Predictable mistakes → cures. "The filaments shorten": they slide. Calling actin the thick filament: myosin is thick and carries the heads. Putting calcium before the nerve signal: ACh comes first. "The junction releases calcium": it releases ACh, and the calcium comes from the reticulum. "ATP is only for contracting" or "relaxation is free": ATP also releases the heads and pumps the calcium back.
  • Deeper review: the Week 10 chapter and slides, and the Feel the Fatigue lab.

Unit 8 — The muscular system (Week 11)

  • Key idea. Muscles only pull, so they work in teams across levers, and the body's usual lever trades force for speed.
  • Attachments. The origin is the attachment on the bone that stays fixed; the insertion is on the bone that moves, and a contracting muscle pulls its insertion toward its origin. The belly lies between.
  • The team, as roles. The agonist (prime mover) is the principal muscle in an action. The antagonist produces the opposite action and relaxes as the agonist contracts. A synergist aids the prime mover, and a fixator stabilizes the bone carrying the origin. The roles belong to the movement, so they swap when the movement reverses.
  • Contraction types. An isotonic contraction changes the muscle's length: concentric when it shortens, eccentric when it lengthens under tension. An isometric contraction develops tension with no change in the joint's angle. Muscle tone is the small, always-on contraction of a resting muscle.
  • Reading a name. Muscle-naming logic reads size, shape, fiber direction, location, number of origins, attachments, or action: gluteus maximus is size, deltoid is shape, rectus is fiber direction, biceps is number of origins.
  • Levers, taught as a model. The bone is the lever, the joint is the fulcrum, the muscle's pull is the effort, and the weight is the load. Name the class by what sits in the middle: fulcrum (first class), load (second class), effort (third class, the body's most common design). The lever law: effort × effort arm = load × load arm. In the course's forearm, 60 N at 36 cm against a 4 cm effort arm needs 540 N, nine times the load.
  • The major muscles by action. Deltoid abducts the arm; pectoralis major draws the arm across the chest; biceps brachii flexes the forearm and helps supinate it; triceps brachii extends the forearm; rectus abdominis flexes the trunk; gluteus maximus extends the hip; quadriceps femoris extends the knee; hamstrings flex the knee and extend the hip; gastrocnemius plantar flexes the foot; tibialis anterior dorsiflexes it.
  • Predictable mistakes → cures. "The origin moves": the insertion is pulled. "The biceps extends the forearm": it flexes; the triceps extends. Treating agonist as a permanent label: it belongs to the movement. "Muscles push": they only pull. "A third-class lever is strong": it is fast, at a force disadvantage.
  • Deeper review: the Week 11 chapter, the lever slides, and the Name the Muscle, Name the Action lab.

Unit 9 — The neuron and the action potential (Week 12)

  • Key idea. A neuron turns a stimulus into a brief electrical flip that runs down its axon, then hands the message across a gap as a chemical.
  • The neuron, structure to function. Dendrites receive signals at synapses; the cell body holds the nucleus and integrates; the axon carries the impulse away from the cell body, starting at the axon hillock; the axon terminals release neurotransmitter; the myelin sheath insulates and speeds conduction; the nodes of Ranvier are the gaps where the signal jumps.
  • The neuroglia. In the brain and spinal cord: astrocytes (support; the blood-brain barrier), oligodendrocytes (myelin there), microglia (resident immune cells), and ependymal cells (help produce cerebrospinal fluid). Outside them: Schwann cells (myelin on peripheral axons) and satellite cells (support cell bodies in ganglia).
  • The values, with their signs. The resting membrane potential is about −70 mV with the inside negative. Threshold is about −55 mV, and the action potential peaks at about +30 mV. From rest to threshold is −55 − (−70) = 15 mV; from rest to the peak is 30 − (−70) = 100 mV.
  • The phases, in order, with their ions. Rest → depolarization (Na⁺ rushes in) → repolarization (Na⁺ channels close, K⁺ flows out) → hyperpolarization (a brief dip below rest, because the K⁺ channels are slow to close) → rest. The gated channels move ions passively and fast during the spike; the pump restores the gradients with ATP afterward.
  • All-or-none. Once threshold is reached the spike is the same full size every time; a stronger stimulus produces more spikes, not bigger ones.
  • Conduction. On a myelinated axon the impulse jumps node to node, saltatory conduction, faster than continuous conduction on an unmyelinated axon. A disease that strips CNS myelin slows or blocks signals.
  • Across the synapse, in order. The action potential reaches the terminal → voltage-gated Ca²⁺ channels open and Ca²⁺ enters → vesicles release neurotransmitter by exocytosis → it crosses the cleft and binds receptors on the next cell. Electrical along the axon, chemical across the gap.
  • Reaction time. The course's ruler drop, 18, 22, 19, 21, and 20 cm, averages 20.0 cm, about 0.20 s in words: a whole chain of action potentials and synapses from eye to brain to hand.
  • Predictable mistakes → cures. Writing a positive resting potential: circle the minus in −70 mV. "Depolarization is potassium leaving": Na⁺ comes in; K⁺ out is repolarization. "Myelin slows the signal": it speeds it. "Oligodendrocytes myelinate the PNS": Schwann cells do. "The signal sparks across the synapse": a chemical crosses the cleft.
  • Deeper review: the Week 12 chapter, the phase table, and the Watch a Neuron Fire lab.

Unit 10 — The central nervous system (Week 13)

  • Key idea. Each job in the brain has an address, and the brain and cord sit inside three wrappings and a cushion of fluid.
  • CNS and PNS. The central nervous system is the brain and the spinal cord; the peripheral nervous system is everything outside them, the nerves and ganglia. Gray matter is dense with cell bodies and dendrites, where signals are processed; white matter is dense with myelinated axons, the wiring.
  • The four lobes. Frontal: motor functions from the precentral gyrus, language production in Broca's area, and personality, short-term memory, and consciousness in the prefrontal areas. Parietal: body sensation (touch, pressure, pain, and position) on the postcentral gyrus. Temporal: primary auditory sensation and memory. Occipital: primary visual perception.
  • The other regions. The cerebellum compares the motor command with sensory feedback and coordinates movement, balance, and posture. The thalamus is the relay for every sensory signal except smell. The hypothalamus holds internal conditions steady, the control center of many homeostatic loops. The brainstem is the midbrain, pons, and medulla oblongata, regulating the heart and breathing.
  • The spinal cord. Gray matter in horns inside, white matter in columns outside; it conducts signals to and from the brain and integrates reflexes.
  • The meninges, outer to inner. Dura mater → arachnoid mater → pia mater, with the subarachnoid space under the arachnoid, where cerebrospinal fluid circulates. CSF is made by the choroid plexus of the four ventricles and cushions the brain, floats it, and carries away metabolic wastes.
  • The reflex arc, in order. Receptor → sensory neuron → interneuron in the spinal cord → motor neuron → effector. The withdrawal reflex fires before the pain reaches awareness, with the antagonist's motor neuron inhibited.
  • A location predicts a deficit. A stroke in the occipital lobe predicts vision loss; a lumbar puncture reaches the subarachnoid space below where the cord ends.
  • Predictable mistakes → cures. "The occipital lobe hears": it sees, and the temporal lobe hears. "The cerebrum coordinates": the cerebellum does. Swapping thalamus and hypothalamus: relay against regulate. Reversing the meninges: dura, arachnoid, pia from the outside in. "CSF carries oxygen like blood": it cushions, floats, and clears waste. "A reflex must go through the brain first": the spinal cord integrates it.
  • Deeper review: the Week 13 chapter, the CNS key, and the Map the Brain lab.

Unit 11 — The peripheral and autonomic nervous system (Week 14)

  • Key idea. Nerves carry traffic in two directions, and an automatic pair of branches holds the organs steady by pushing in opposite directions.
  • The nerves. There are 12 pairs of cranial nerves, CN I through CN XII; the olfactory (CN I), optic (CN II), and vestibulocochlear (CN VIII) nerves are purely sensory, and the vagus nerve (CN X) runs beyond the head to the organs of the chest and upper abdomen. There are 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal, and every spinal nerve is a mixed nerve, carrying both sensory and motor axons.
  • Traffic. Afferent signals travel from receptors toward and into the CNS; efferent signals travel out of the CNS to muscles and glands. Afferent arrives, efferent exits.
  • Somatic and autonomic. The somatic nervous system carries commands to skeletal muscle, for chosen movements and somatic reflexes. The autonomic nervous system carries automatic commands to smooth muscle, cardiac muscle, and glands, mostly to keep internal conditions steady.
  • The two branches. The sympathetic division is fight-or-flight: thoracolumbar, releasing norepinephrine at most targets, it speeds the heart, dilates the pupils, opens the airways, pauses digestion, and triggers sweating. The parasympathetic division is rest-and-digest: craniosacral, releasing acetylcholine, it slows the heart through the vagus, constricts the pupils, and promotes digestion. With dual innervation both branches reach the same organ, an antagonistic pair whose balance is homeostasis at work. The gas-pedal-and-brake picture is a classroom model.
  • The course's heart-rate table (illustrative). Resting 62, right after activity 98, and one minute after 72 beats per minute. The rise of 98 − 62 = 36 is the sympathetic branch; the first-minute fall of 98 − 72 = 26 is the parasympathetic branch re-engaging. Each average is the table's own value, never a norm. Left to itself the pacemaker would fire at roughly 100 beats per minute.
  • Predictable mistakes → cures. "Afferent means away": afferent arrives. "The autonomic system moves skeletal muscle": the somatic system does. "The parasympathetic branch speeds the heart for exercise": the sympathetic branch does. Treating the branches as one thing: they do opposite jobs on the same organs. Misstating the counts: 12 and 31.
  • Deeper review: the Week 14 chapter, the two-column antagonism table, and the Reading Your Own Autopilot lab.

Unit 12 — The special senses (Week 15)

  • Key idea. Every sense organ does two jobs: it captures its stimulus and converts it into a nerve signal the brain can read.
  • Receptor classes. Chemoreceptors respond to chemicals (taste, smell), mechanoreceptors to pressure, vibration, sound, and position, photoreceptors to light, thermoreceptors to heat or cold, and nociceptors to the tissue damage felt as pain. The skin carries mechanoreceptors, thermoreceptors, and nociceptors.
  • The eye, in the order light travels. Cornea → pupil → lens → retina. The cornea admits light and, with the lens, focuses it; the iris sizes the pupil; the lens does the fine focusing and changes shape for near and far, accommodation. In the retina, rods are sensitive in low light and detect no color, and cones work in bright light and detect color. The fovea gives the sharpest vision, and the optic disc has no photoreceptors, the blind spot.
  • The ear, outside in. Pinna and auditory canal → tympanic membrane → malleus → incus → stapes → oval window → cochlea, whose hair cells convert vibration into nerve signals for hearing. The semicircular canals sense the head turning and the vestibule senses head position, together serving equilibrium. Both hearing and equilibrium travel on the vestibulocochlear nerve.
  • Taste and smell. Taste buds in the tongue's papillae respond to five basic tastes: sweet, salty, sour, bitter, and umami. Spicy is a pain-and-temperature signal, not a taste. Smell runs on the olfactory epithelium. Both are chemoreception, and flavor is mostly smell.
  • Predictable mistakes → cures. "Rods see color": cones see color, rods work in the dark. "The lens does most of the focusing": the cornea and lens focus together, and the lens accommodates. Scrambling the light path or the ossicles. "The cochlea handles balance": it hears, and the canals balance. "Spicy is a taste."
  • Deeper review: the Week 15 chapter, the special-senses key, and the Test Your Own Senses lab.

Representative practice

These are fresh variants, not the exam's questions. Every scenario and every dataset here is illustrative, constructed for this guide, unless it names a course dataset. Work each one, then check it.

Worked example 1 — a house thermostat and two test samples (Units 1 and 2)

A house thermostat is a classroom model of a feedback loop. On a cold night the room cools below the temperature the thermostat is set to, and the furnace runs until the room warms back up.

  1. Receptor: the thermometer inside the thermostat senses the room's temperature and reports it.
  2. Control center: the thermostat compares that reading with its setting, the model's set point.
  3. Effector: the furnace acts to raise the temperature.
  4. Loop type: the response opposes the change, so the loop is negative feedback. In the body, the hypothalamus is the control center, and the effectors are structures such as dermal arterioles and sweat glands.
  5. Two test samples: illustrative sample A reads pH 6 and sample B reads pH 8. Count from 6 up to 8: two steps, so 10² = 10 × 10 = 100 times more hydrogen ions in sample A, never 20.

Why it matters: every loop runs receptor, then control center, then effector, and a pH comparison is a count of steps raised to a power of ten.

Worked example 2 — a teaching beaker and a busy pump (Unit 2)

An illustrative model cell holds 300 mOsm/L.

  1. A 250 mOsm/L bath: 250 < 300, so the bath is hypotonic; water moves into the cell, and the cell swells.
  2. A 400 mOsm/L bath with an equal volume of pure water poured in: the volume doubles, and C₁V₁ = C₂V₂, so 400 × 1 = C₂ × 2, and C₂ = 400 ÷ 2 = 200 mOsm/L. Since 200 < 300, the watered-down bath is also hypotonic, and the cell would swell.
  3. The pump at work: 5 ATP × 3 Na⁺ = 15 Na⁺ out, and 5 ATP × 2 K⁺ = 10 K⁺ in. The pump runs against both gradients, so it is active transport.

Why it matters: compare from the cell's side, name the bath, then say where the water goes.

Worked example 3 — one glucose's trip and a short model gene (Unit 3)

  1. Follow one glucose, in order and in place: glycolysis in the cytoplasm splits it into two pyruvate and nets 2 ATP → the citric acid cycle in the mitochondrial matrix releases the carbons as CO₂ → the electron transport chain on the inner mitochondrial membrane makes the most ATP, and oxygen accepts the electrons and forms water.
  2. A model gene: the template strand reads 3′-TAC TTC CGA ACT-5′. Codon key, from the course's codon chart: AUG = Met (start); AAG = Lys; GCU = Ala; UAA, UAG, UGA = stop.
  3. Pair each base (A → U, T → A, G → C, C → G): TAC → AUG, TTC → AAG, CGA → GCU, ACT → UGA, so the mRNA is 5′-AUG AAG GCU UGA-3′, with no T anywhere.
  4. Count: 12 bases ÷ 3 = 4 codons, and 4 − 1 stop = 3 amino acids: Met–Lys–Ala, then stop.

Why it matters: both chains are read forward with a place for every step, and three bases make one codon.

Worked example 4 — out of a warm pool into the wind (Unit 4)

A swimmer climbs out of a heated pool into a cold breeze. Trace the skin's response as the Week 1 loop, by structure.

  1. Receptor: thermoreceptors in the skin sense the surface cooling and report it.
  2. Control center: the hypothalamus compares the report with the set point of about 37 °C.
  3. Effectors: dermal arterioles constrict, so less warm blood flows near the surface; the arrector pili contract and stand the hairs up as goosebumps; sweating stops.
  4. Tissue read: the arrector pili is muscle tissue, the arterioles sit in the dermis, a vascular connective-tissue layer, and the epidermis above them has no vessels of its own.

Why it matters: a skin response is a feedback loop read by structure, receptor first and effector last.

Worked example 5 — a sawn-open model of a tibia (Unit 5)

An anatomy-lab model of an adult tibia is cut lengthwise. Read it from the outside of the shaft inward, then at one end.

  1. The shaft, outside in: periosteum → compact bone built from osteons → endosteum → medullary cavity with yellow marrow. This is the diaphysis.
  2. One end: articular cartilage over the joint surface → spongy bone, a lattice of trabeculae with red marrow and no osteons. This is an epiphysis.
  3. Between them: an epiphyseal line, left where the epiphyseal plate was replaced by bone, so the bone has stopped lengthening.
  4. Who keeps it alive: osteocytes in their lacunae maintain the matrix, while osteoclasts and osteoblasts keep remodeling it in response to stress.

Why it matters: the shaft and the end are built differently because they do different jobs.

Worked example 6 — a museum skeleton, counted by region (Unit 6)

An illustrative museum display shows an adult skeleton with labeled regions.

  1. One hand and wrist: 8 carpals + 5 metacarpals + 14 phalanges = 27 bones; both hands: 27 × 2 = 54 bones.
  2. The rest of one upper limb: 30 − 27 = 3 bones, the humerus, the radius, and the ulna.
  3. The axial skeleton without the skull: 80 − 22 = 58 bones.
  4. The thoracic cage: 12 pairs × 2 = 24 ribs, and 24 + 1 sternum = 25 bones; by type, 7 true pairs + 5 false pairs = 12 pairs, with 2 floating pairs inside the false group.
  5. Two joints on the display: the joint between the atlas and the axis is synovial → diarthrosis → pivot, and it allows rotation, the head's "no." A skull suture is fibrous → synarthrosis, with no cavity, so it is not synovial.

Why it matters: every count adds back to the course's 206 = 80 + 126, and every joint reads structure, then function, then type.

Worked example 7 — a calf-raise fatigue series (Unit 7)

At home, an illustrative set of five 15-second calf-raise trials, with rests between, gives 20, 18, 16, 14, and 12 raises.

  1. Sum: 20 + 18 + 16 + 14 + 12 = 80 raises.
  2. Average: 80 ÷ 5 = 16 raises per trial.
  3. Total drop: 20 − 12 = 8 raises.
  4. Percent decline: 8 ÷ 20 × 100 = 40%.
  5. Trial-to-trial fall: a steady 2 raises per trial, and 4 gaps × 2 = 8, the same as the total drop.
  6. Read the trend: ATP is spent faster than it is remade and lactic acid lowers the pH inside the fibers, so fewer cross-bridges cycle in each trial; the filaments never shorten.

Why it matters: divide the drop by the first trial, never the last, and read the trend as cross-bridges, not filament length.

Worked example 8 — rising onto the toes (Unit 8)

In the course's lever model of rising onto the toes, the toes, where the foot pivots, are the fulcrum, and the body's weight is the load. The effort is the muscle pull that raises the heel. Raising the heel is plantar flexion, and of the course's ten muscles the gastrocnemius is the one that plantar flexes the foot, so in this model it supplies the effort. Use illustrative numbers: a 480 N load sits 12 cm from the fulcrum, and the effort is applied 16 cm from it, on the same side.

  1. Classify: the load, 12 cm out, sits between the fulcrum and the effort, 16 cm out, so the load is in the middle and the lever is second class.
  2. Lever law: effort × 16 cm = 480 N × 12 cm = 5,760 N·cm, so effort = 5,760 ÷ 16 = 360 N.
  3. Compare: 360 ÷ 480 = 0.75, so the effort is three quarters of the load. A second-class lever gains force, the opposite of the third-class forearm, where the course's biceps pulls 540 N for a 60 N load.
  4. Contraction types: rising onto the toes, the gastrocnemius shortens, a concentric contraction; holding still on the toes is isometric; lowering slowly back down is eccentric.
  5. Roles: the gastrocnemius is the agonist for plantar flexion, and the tibialis anterior, which dorsiflexes, is its antagonist.

Why it matters: name the class by what sits in the middle, then multiply each force by its own arm.

Worked example 9 — signed differences and a nerve in the arm (Unit 9)

Use the course's action-potential values: rest about −70 mV, threshold about −55 mV, and peak about +30 mV.

  1. Threshold to peak: 30 − (−55) = 30 + 55 = 85 mV of rise during depolarization.
  2. Peak back to rest: 30 − (−70) = 30 + 70 = 100 mV of fall, during repolarization.
  3. Check: 15 mV (rest to threshold) + 85 mV (threshold to peak) = 100 mV, the full upstroke.
  4. Phases with ions: rest → depolarization (Na⁺ in) → repolarization (K⁺ out) → hyperpolarization → rest.
  5. A myelinated nerve fiber in the forearm: it lies outside the brain and spinal cord, so a Schwann cell made its myelin, and the impulse jumps node to node by saltatory conduction, faster than on an unmyelinated fiber.

Why it matters: every potential keeps its sign, and every difference is a signed subtraction.

Worked example 10 — a needle's path and an illustrative lesion (Unit 10)

  1. A lumbar puncture's needle: it passes the dura mater → the arachnoid mater → into the subarachnoid space, so it crosses 2 layers to reach the cerebrospinal fluid and stops short of the pia mater. It enters below where the spinal cord ends.
  2. Counting the CNS key: 4 lobes + 3 brainstem parts + 3 meninges + 4 ventricles + 5 reflex-arc parts = 19 items.
  3. An illustrative lesion: in an illustrative case, damage is limited to the postcentral gyrus of the parietal lobe. The predicted loss is body sensation, touch, pressure, pain, and position, not movement, which starts on the precentral gyrus of the frontal lobe.
  4. A hand on a hot pan handle: receptor → sensory neuron → interneuron in the spinal cord → motor neuron → effector, 5 parts, and the hand pulls back before the pain reaches awareness.

Why it matters: a location predicts a job, and a path is read layer by layer in order.

Worked example 11 — heart-rate counts around a minute of jumping jacks (Unit 11)

An illustrative heart-rate table, in beats per minute, holds three counts at rest (66, 70, and 68), three right after a minute of jumping jacks (110, 114, and 112), and three one minute later (82, 86, and 84). Each average is the table's own value, never a norm.

  1. Resting average: 66 + 70 + 68 = 204, and 204 ÷ 3 = 68 beats per minute.
  2. After-activity average: 110 + 114 + 112 = 336, and 336 ÷ 3 = 112 beats per minute.
  3. One-minute-after average: 82 + 86 + 84 = 252, and 252 ÷ 3 = 84 beats per minute.
  4. Rise: 112 − 68 = 44 beats per minute, the sympathetic branch speeding the heart.
  5. First-minute fall: 112 − 84 = 28 beats per minute, the parasympathetic branch re-engaging, largely through the vagus.
  6. Recovery check: 84 − 68 = 16 beats per minute still above the resting average, so one minute is not a full return.
  7. Somatic or autonomic: doing the jumping jacks is somatic, a chosen movement of skeletal muscle; the heart speeding up is autonomic.
  8. The nerve counts: 12 cranial pairs + 31 spinal pairs = 43 pairs, and 43 × 2 = 86 nerves.

Why it matters: one effector, two branches, and the rise and the fall are both subtractions from averages.

Worked example 12 — a night drive and a dizzy playground (Unit 12)

  1. The sound path from the outside: pinna → auditory canal → tympanic membrane → malleus → incus → stapes → oval window → cochlea, 2 + 1 + 3 + 1 + 1 = 8 structures, with the conversion in the cochlea's hair cells.
  2. Ossicles in the skeleton: 3 per ear × 2 ears = 6, and 1 hyoid + 6 = 7 associated bones of the axial skeleton.
  3. A night drive on an unlit road: in dim light only the rods fire, and rods detect no color, so the roadside looks gray.
  4. Spinning after a playground ride: the room seems to keep turning after the ride stops, which points to the fluid in the semicircular canals, not the cochlea.

Why it matters: name the path in order, then the receptor at its end, then what a lost ability points to.

Self-check questions

  1. Which plane cuts the body into a top part and a bottom part, and what is the cut called? Self-check: the transverse plane; it makes a cross-section. Why: a sagittal plane makes left and right parts, and a frontal plane makes front and back parts.
  2. What is a blood pH below 7.35 called? Self-check: acidosis. Why: blood is defended between 7.35 and 7.45, and above the range is alkalosis.
  3. Which organelle makes phospholipids and steroid hormones? Self-check: the smooth ER. Why: the rough ER, studded with ribosomes, makes proteins.
  4. Why is cartilage slow to heal? Self-check: it is avascular. Why: with no blood vessels of its own, its nutrients diffuse in through the matrix.
  5. An adult bone shows an epiphyseal line. What does that tell you? Self-check: the bone has stopped lengthening. Why: the line is bone left where the epiphyseal plate was replaced.
  6. Which joint type allows the widest range of motion, and where are the only two? Self-check: ball-and-socket, at the hip and the shoulder. Why: a rounded bone end turns freely in a cup.
  7. Which regulatory protein binds Ca²⁺ first? Self-check: troponin. Why: troponin then moves tropomyosin off actin's binding sites.
  8. What does the name tibialis anterior tell you, and what does the muscle do? Self-check: its location, anterior and beside the tibia; it dorsiflexes the foot. Why: it is named for its anterior place by the tibia, and it dorsiflexes the foot, lifting its front.
  9. Which glial cell helps form the blood-brain barrier? Self-check: the astrocyte. Why: microglia are immune cells, and ependymal cells help produce cerebrospinal fluid.
  10. Which region relays every sensory signal except smell? Self-check: the thalamus. Why: the hypothalamus regulates internal conditions.
  11. Do sympathetic neurons leave the cord at the thoracic and upper lumbar levels or at the brainstem and sacral levels? Self-check: thoracic and upper lumbar, thoracolumbar. Why: the parasympathetic division is craniosacral.
  12. A meal tastes flat during a stuffy cold. Which sense is mostly missing? Self-check: smell. Why: flavor is mostly smell, so the taste buds are not the main loss.

Check yourself — choose one. (a) Which unit in this guide felt least familiar, and which worked example would you redo first? (b) Pick one early habit, such as structure determines function or say the order and name the place, and explain in two sentences how it changes the way you read one Weeks 9–15 topic. Either choice is a good use of ten minutes.

Study plan

A short countdown sized to a course that meets twice a week. Count backward from the day the final opens in Week 16.

  • Two weeks out: review Units 1–5 in one sitting and redo Worked examples 1 through 5 from scratch. These ideas return inside later questions.
  • Ten days out: review Units 6 and 7. Redo Worked examples 6 and 7 until each step comes with its reason. Weeks 9 and 10 carry 12 of the 40 questions.
  • One week out: review Units 8 and 9. Redo Worked examples 8 and 9 without looking, writing every unit and every sign. Week 12 carries 7 questions, the most of any week.
  • Five days out: take the paired practice exam once, closed-book and under exam-like conditions, then sort every miss by week. Remember that it reaches into Weeks 1–7 far more than the final does.
  • Four days out: review Units 10–12 and redo Worked examples 10, 11, and 12.
  • Three days out: run the paired exam-prep tutorial (the copy/paste chatbot tutor, or its no-AI route) on the two units that felt weakest, with at least one from Units 6–12.
  • Two days out: work the twelve self-check questions cold, then retake the practice exam.
  • The day before: skim the "Predictable mistakes → cures" lines in every unit and watch one video from the list below. Sleep.

Use the exam-prep tutorial and the practice exam for active recall; this guide is for review, and those two are where you rehearse. Rereading alone does less for you than retrieval practice does.

Watch before the exam

These videos come from the course's own weekly readings. Use them to retrieve what you already learned and to connect weeks, not for new material.

Exam format and how it is graded

The final is graded automatically, and all 40 questions count the same. The questions appear one at a time, and you cannot go back to an earlier question once you move on. You have one attempt and no time limit. AI tools are not permitted on the final.

Test-taking strategies for this material:

  • For any process, say the steps in order and the place each one happens before you choose.
  • For any directional term, stand the body in the anatomical position first, palms forward.
  • For a membrane potential, write the sign before the number, and find a difference by signed subtraction.
  • For a calculation, write each step with its unit: add before you divide, and divide a drop by the first value before you multiply by 100.
  • For a lever, find what sits in the middle before you name the class, and multiply each force by its own arm.
  • For a pair of look-alike terms, name the one word that separates them: osteoblast or osteoclast, origin or insertion, afferent or efferent, sympathetic or parasympathetic, rods or cones, cochlea or canals.
  • For a model, such as the sliding filament model, the lever model, or the gas pedal and brake, remember that it is a classroom model and does not describe every real case.
  • Since you cannot go back, settle each question before you move on.

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