Human Anatomy & Physiology – Comprehensive Vocabulary Review

These vocabulary flashcards summarize and define the principal terms, structures, and physiological concepts presented throughout the lecture notes, providing a broad yet concise review for exam preparation.

Chemical Level

The simplest level of organization; involves atoms and molecules.

Biological Macromolecule

Large organic molecule (protein, carbohydrate, nucleic acid, lipid) that builds living organisms.

Organelle

Microscopic membrane-bound structure within cells formed from macromolecules.

Cell

Smallest living unit; basic structural and functional unit of life.

Tissue

Group of similar cells performing a common function; four basic types exist.

Organ

Structure composed of two or more tissue types performing specific complex functions.

Organ System

Group of related organs coordinating activities to achieve a common function (e.g., digestive system).

Organism

Highest level of organization; a living individual with independently functioning body systems.

Anatomical Position

Body standing upright, feet parallel, arms at sides, palms facing forward, eyes forward.

Superior

Toward the head or upper part of a structure; above.

Inferior

Away from the head; toward the lower part of a structure; below.

Lateral

Farther from the midline of the body.

Distal

Farther from the point of attachment to trunk.

Positive Feedback

Homeostatic mechanism that reinforces a stimulus, driving the process in the same direction.

Decomposition Reaction

Catabolic, exergonic reaction breaking a large molecule into smaller ones; releases energy.

Synthesis Reaction

Anabolic, endergonic reaction combining two or more structures into a larger one; requires energy.

Enzyme

Protein catalyst that lowers activation energy to speed chemical reactions.

Active Site

Region on an enzyme where the substrate binds.

Competitive Inhibitor

Substance resembling substrate that binds the active site, blocking substrate binding.

Noncompetitive (Allosteric) Inhibitor

Molecule binding to a site other than the active site, altering enzyme shape and function.

Saturation (Enzyme)

Condition in which every enzyme active site is occupied by substrate; reaction rate maxes out.

Feedback Inhibition

End product of a metabolic pathway allosterically inhibits an enzyme earlier in the pathway.

Endoplasmic Reticulum (ER)

Extensive membranous network; rough ER synthesizes proteins, smooth ER synthesizes lipids & detoxifies.

Rough ER

ER studded with ribosomes; produces proteins for secretion or membrane insertion.

Smooth ER

ER lacking ribosomes; lipid synthesis, carbohydrate metabolism, calcium storage, detoxification.

Golgi Apparatus

Stacked cisternae that modify, package, and sort proteins and lipids for delivery.

Lysosome

Membranous vesicle containing digestive enzymes for intracellular digestion and autophagy.

Peroxisome

Membranous organelle with oxidative enzymes that detoxify and break down fatty acids.

Mitochondrion

Double-membrane organelle; site of aerobic ATP production.

Ribosome

Non-membranous organelle composed of rRNA and protein; site of protein synthesis.

Cytoskeleton

Network of protein filaments (microfilaments, intermediate filaments, microtubules) providing structure and transport.

Centrosome

Region containing a pair of centrioles; organizes microtubules and spindle fibers.

Proteasome

Protein complex that degrades unneeded or damaged proteins via proteolysis.

Centriole

Cylindrical bundle of microtubules within the centrosome; aids cell division.

Deoxyribonucleotide

Monomer of DNA consisting of deoxyribose sugar, phosphate, and nitrogenous base.

Complementary Base Pairing

DNA rule: adenine pairs with thymine, cytosine pairs with guanine.

Chromatin

DNA plus associated proteins in a non-dividing cell; loosely coiled.

Chromosome

Tightly coiled DNA wrapped around histones, visible during cell division.

Desmosome

Button-like cell junction providing mechanical strength (e.g., skin).

Tight Junction

Seals adjacent cells, preventing passage of substances between them.

Gap Junction

Protein channels allowing direct communication and ion flow between cells.

Extracellular Matrix

Ground substance plus protein fibers occupying space outside connective tissue cells.

Apical Surface

Free surface of an epithelium exposed to body exterior or cavity.

Basement Membrane

Layer of collagen & glycoproteins anchoring epithelium to underlying connective tissue.

Mitosis

Process of somatic cell division producing two genetically identical daughter cells.

Connective Tissue

Tissue type providing support, protection, binding, storage, transport, immunity.

Areolar Connective Tissue

Loose CT that cushions organs and binds epithelium to deeper tissues.

Adipose Tissue

CT storing energy, insulating, and cushioning organs.

Reticular Tissue

Loose CT forming supportive stroma of lymphatic organs.

Dense Regular Connective Tissue

Parallel collagen fibers providing strong attachment (tendons, ligaments).

Dense Irregular Connective Tissue

Interwoven collagen fibers resisting stress in all directions (dermis).

Elastic Connective Tissue

CT with abundant elastic fibers allowing stretch and recoil (arterial walls).

Bone (Osseous Tissue)

Supporting CT providing levers, protection, and mineral storage.

Blood

Fluid connective tissue with erythrocytes transporting gases and plasma transporting nutrients.

Skeletal Muscle

Voluntary, striated, multinucleated fibers that move the skeleton and generate heat.

Cardiac Muscle

Involuntary, striated, branched fibers with intercalated discs; pumps blood.

Smooth Muscle

Involuntary, non-striated spindle cells in organs; moves substances and controls lumen size.

Pseudostratified Epithelium

Single layer appearing multilayered because nuclei are at different heights; not all cells reach surface.

Integumentary System Functions

Protection, water balance, vitamin D synthesis, temperature regulation, sensation, excretion, immunity.

Epidermis

Keratinized stratified squamous epithelium forming skin’s outer layer.

Dermis

Dense irregular connective tissue layer beneath epidermis containing blood vessels and nerves.

Stratum Corneum

Outer 20–30 layers of dead, keratin-filled cells providing abrasion resistance.

Stratum Lucidum

Clear 2-3 cell layers present only in thick skin (palms, soles).

Stratum Granulosum

3-5 layers where keratinization begins; cells contain keratohyalin granules.

Stratum Spinosum

Several layers of polygonal keratinocytes connected by desmosomes; contains dendritic cells.

Stratum Basale

Deepest epidermal layer; mitotic keratinocytes, melanocytes, tactile cells present.

Thick Skin

Skin with all five epidermal strata, sweat glands, no hair or sebaceous glands; palms/soles.

Thin Skin

Covers most body, lacks stratum lucidum, contains hair, sebaceous & sweat glands.

Compact Bone

Dense, strong bone with osteons forming outer diaphysis; ~80 % of bone mass.

Spongy Bone

Trabecular, porous bone in epiphyses and flat bones; houses red marrow; ~20 % mass.

Parathyroid Hormone (PTH)

Hormone elevating blood calcium by stimulating osteoclasts and reducing renal calcium loss.

Calcitriol

Active vitamin D acting with PTH to raise blood calcium by increasing intestinal absorption and renal re-uptake.

Calcitonin

Thyroid hormone lowering blood calcium by inhibiting osteoclasts; more influential in children.

Endochondral Ossification

Bone development replacing a hyaline cartilage model with bone tissue (most bones).

Cervical Vertebrae

Seven small neck vertebrae (C1–C7) with transverse foramina; support head.

Thoracic Vertebrae

Twelve vertebrae (T1–T12) each articulating with ribs; heart-shaped bodies.

Lumbar Vertebrae

Five large vertebrae (L1–L5) bearing body weight; thick bodies and blunt spinous processes.

Sacrum

Five fused vertebrae forming posterior pelvis between hip bones.

Coccyx

Tailbone of 3–5 fused vertebrae; attachment site for ligaments and muscles.

Pollex

Thumb; has only proximal and distal phalanges.

Tarsal Bones

Seven ankle bones: calcaneus, talus, navicular, cuboid, and three cuneiforms.

Flexion

Movement decreasing the angle between bones in the sagittal plane.

Extension

Movement increasing the angle between bones; returns from flexion.

Hyperextension

Extension beyond anatomic position’s normal range.

Abduction

Lateral movement away from body midline.

Circumduction

Circular motion combining flexion, abduction, extension, and adduction.

Coxal (Hip) Joint

Ball-and-socket joint between femoral head and acetabulum; strong and stable.

Glenohumeral (Shoulder) Joint

Ball-and-socket joint of humeral head & scapular glenoid cavity; mobile but unstable.

Talocrural Joint

Ankle joint between tibia, fibula, and talus.

Inversion

Movement of sole medially (turning foot inward).

Motor Unit

Single motor neuron plus all skeletal muscle fibers it innervates.

Sarcomere

Functional contractile unit of muscle fiber between two Z-discs.

Cross-Bridge Cycling

Repeated myosin-actin interactions producing muscle contraction.

Power Stroke

Myosin head pivots pulling actin toward sarcomere center; ADP & Pi released.

Isometric Contraction

Muscle produces tension without changing length; no movement occurs.

Isotonic Contraction

Muscle changes length while maintaining constant tension; movement occurs.

Agonist (Prime Mover)

Muscle primarily responsible for producing a specific movement.

Antagonist

Muscle that opposes the action of an agonist, providing control.

Synergist

Muscle assisting agonist by adding force or reducing undesirable movements.

Fixator

Synergist that immobilizes a bone or joint, stabilizing the agonist’s origin.