Intro to the Human Body
Lesson focus - Define anatomy and physiology, describe the levels of structural organization and tissue types, explain homeostasis and feedback systems, apply anatomical terminology and body cavities, recognize basic medical word parts, and describe medical imaging procedures.
Anatomy and Physiology Defined
| Term | Definition |
|---|---|
| Anatomy | The science of body structures and the relationships among them |
| Physiology | The science of body functions and how the body parts work |
Levels of Structural Organization and Body Systems
The body is organized from the simplest to the most complex level.
| Level | Description |
|---|---|
| Chemical | Atoms (smallest units of matter) and molecules (two or more atoms joined together) |
| Cellular | Cells - the smallest living units in the human body |
| Tissue | Groups of cells and the materials surrounding them that work together to perform a particular function |
| Organ | Two or more different types of tissues that serve particular functions for the body |
| System | Related organs with common functions |
| Organismal | Any living individual |
Types of Tissue
| Tissue | Function |
|---|---|
| Epithelial | Covers body surfaces, lines hollow organs and cavities, and forms glands |
| Connective | Connects, supports, and protects body organs |
| Muscular | Contracts to make body parts move; generates heat |
| Nervous | Carries information from one part of the body to another through nerve impulses |
| Adipose | Maintains insulation, stores triglycerides, and acts as a shock absorber for muscle tissue and movement |
Glands
Glands secrete substances into ducts, onto surfaces, or into the blood.
- Endocrine glands - secrete hormones
- Exocrine glands - secrete sweat, mucus, and digestive fluids
Characteristics of the Living Human Organism
- Metabolism - the sum of all chemical processes that occur in the body
- Catabolism - the breakdown of complex chemical substances into smaller components (generally exergonic)
- Anabolism - the building up of complex chemical substances from smaller, simpler components (generally endergonic)
- Responsiveness - the body's ability to detect and respond to change
- Movement
- Growth
- Differentiation - the development of a cell from unspecialized to specialized
- Reproduction
Homeostasis
Homeostasis is the maintenance of relatively stable conditions in the body's internal environment. It is regulated by the nervous system and the endocrine system.
| Feedback system | Action |
|---|---|
| Negative feedback | Reverses a change in a controlled condition |
| Positive feedback | Strengthens or reinforces a change in one of the body's controlled conditions |
Homeostatic Imbalances
| Term | Meaning |
|---|---|
| Disorder | Abnormality of structure or function |
| Disease | Illness characterized by a recognizable set of signs and symptoms |
Related Sciences
| Science | Focus |
|---|---|
| Epidemiology | Why, when, and where diseases occur and how they are transmitted |
| Pharmacology | The effects and uses of a drug in the treatment of disease |
| Diagnosis | Distinguishing one disorder or disease from another |
Basic Anatomical Terminology
Body Positions
| Position | Description |
|---|---|
| Anatomical position | Subject stands erect facing the observer; head level and eyes forward; lower limbs parallel with feet flat on the floor and directed forward; upper limbs at the sides with palms turned forward |
| Prone | Lying face down |
| Supine | Lying face up |
Body Regions
- Head
- Neck
- Trunk
- Upper limbs
- Lower limbs
Directional Terms
| Term | Meaning |
|---|---|
| Lateral | Farther from the midline |
| Medial | Nearer to the midline |
| Proximal | Nearer to the attachment or origination of the structure |
| Distal | Farther from the attachment or origination of the structure |
| Superficial | Toward or on the surface of the body |
| Deep | Away from the surface of the body |
| Superior | Toward the head or upper part of a structure |
| Inferior | Away from the head or the lower part of a structure |
| Anterior | Toward the front |
| Posterior | Toward the back |
Planes and Sections
- Horizontal / Transverse plane
Important Lines
- Vertebral line
- Scapular line
- Mid-sternal line
- Mid-clavicular line
- Anterior axillary line
- Mid-axillary line
Body Cavities
| Cavity | Contents |
|---|---|
| Cranial cavity | Brain |
| Vertebral canal | Spinal cord |
| Thoracic cavity | Pericardial cavity (heart) and pleural cavity (lungs) |
| Diaphragm | Diaphragm |
| Abdominal cavity | Stomach, spleen, liver, intestines |
| Pelvic cavity | Bladder, genital systems |
Viscera are the organs inside the thoracic and abdominal/pelvic cavities.
Basic Medical Terminology
Medical terms are built from prefixes, roots, and suffixes.
| Word part | Meaning | Example |
|---|---|---|
| -ache | Pain | headache, backache, earache |
| aden(o) | Gland, glandular tissue | adenoids, adenotomy |
| aer(o) | Air, oxygen, gas | aerobic, aerate, aerosol |
| -algia | Pain | gastralgia, neuralgia, arthralgia |
| angi(o) | Blood vessel | angioplasty, angioma |
| ante- | Before, forward, in front of | antepartum, anteflexion, anterior |
| -ase | Enzyme | protease, urease, amylase, lactase |
| brady- | Slow | bradycardia, bradypnea |
| bronch | Bronchial tube, bronchus | bronchoscope, bronchogram, bronchitis |
| carcin(o) | Cancer | carcinogen, carcinoma, carcinogenic |
| cardi(o) | Heart | cardiac, cardiotonic, cardiovascular |
| -cele | Hernia, protrusion, tumor | cystocele, meningocele, encephalocele |
| -centesis | Surgical puncture (aspiration of fluid) | amniocentesis, arthrocentesis, paracentesis |
| cephal(o) | Head | cephalogram |
| cerebr(o) | Cerebrum, brain | cerebrospinal, cerebral, cerebrovascular |
| cervic(o) | Neck, cervix | cervical, cervicitis |
| chol(e) | Bile, gall | cholerrhea, cholelithiasis |
| chondr(o) | Cartilage | chondral, hypochondriac |
| -coccus, -cocci | Bacteria, organism | pneumococcus, gonococcus |
| col(o) | Colon | colitis, colonoscopy |
| cost(o) | Rib | costal, intercostal, costophrenic |
| cyan(o) | Blue, blueness | cyanosis |
| cyt(o) | Cell | cytology, cytoplasm |
| derm(o), dermat(o) | Skin | dermis, dermatitis |
| dors(o) | Back | dorsal, dorsolateral |
| dys- | Difficult, abnormal, bad | dyspnea |
| -ectomy | Excision, removal, to cut out | appendectomy, thrombectomy, gastrectomy |
| -emia | Blood condition | anemia, septicemia, leukemia |
| end(o)- | Inside, internal, within | endocrine, endoscope |
| enter(o) | Intestine | enteric |
| epi- | Outer, upon | epidermis |
| erythr(o)- | Red | erythrocyte, erythema |
| eu- | Normal, well, good | euphoria, eupnea |
| extra- | Outside, beyond | extracellular |
| gastr(o) | Stomach | gastric |
| -genic | Producing, originating, forming | pyogenic, carcinogenic |
| ger(o) | Old age | geriatric |
| gloss(o) | Tongue | glossitis |
| gluc(o) | Sugar | glucose, glucagon |
| glyc(o) | Sugar, sweet | hyperglycemia |
| -gram | Picture, graph, record | cardiogram |
| -graph | Recording instrument | cardiograph |
| hem(o)-, hemat(o)- | Blood | hemorrhage, hemoglobin, hemostasis, hematoma, hematemesis |
| hemi- | Half | hemidiaphragm |
| hepat(o)- | Liver | hepatitis |
| hist(o)- | Tissue | histamine, histology |
| homo- | Same, alike, similar | homogenous |
| hydr(o) | Water | hydration |
| hyper- | Excessive, high, above | hypertension, hypertonic |
| hypo- | Deficient, low, below, under | hypoglycemia, hypotonic |
| immuno- | Immune | immunodeficiency |
| infra- | Below, beneath | infraclavicular |
| inter- | Between, among | intercostal |
| intra- | Within, inside | intravenous, intramuscular, intradermal |
| iso- | Equal, same | isotonic |
| -itis | Inflammation | bronchitis |
| laryng(o) | Larynx, voice box | laryngitis, laryngospasm, laryngoscope |
| leuk(o)- | White | leukemia, leukocyte |
| lingu | Tongue | sublingual |
| lip(o) | Fat | lipid, lipoprotein |
| -lysis | Breakdown, destruction | urinalysis, histolysis, thrombolysis |
| macro- | Large | macrocyte |
| mal- | Bad, abnormal, inadequate | malnutrition, malpractice |
| -malacia | Soft, softening | tracheomalacia |
| megalo- | Large, enlarged | megalocyte |
| -megaly | Enlargement | cardiomegaly |
| -metry | Process of measuring | spirometry |
| nas(o)- | Nose | nasal |
| -natal | Birth, infant | prenatal, postnatal, neonatal |
| nephr(o)- | Kidney | nephrology |
| neur(o)- | Nerve | neurology |
| -oma | Tumor, abnormal growth | carcinoma |
| -osis | Condition, increase | acidosis |
| -pathy | Disease, anomaly | myopathy |
| -penia | Deficiency, low number | leukopenia |
| peri- | Near, around, surrounding | pericardium |
| phag(o)- | Eat, swallow, consume | phagocyte, dysphagia |
| pharyng(o)- | Pharynx | pharyngitis |
| phleb(o)- | Vein | phlebotomy |
| -phobia | Fear of | hydrophobia |
| -plasia | Development, formation | hyperplasia |
| -plasty | Surgical repair | rhinoplasty |
| -plegia | Paralysis | hemiplegia |
| -pnea | Breathing, breath | apnea, tachypnea, orthopnea |
| pneum(o)- | Air, lung | pneumonia |
| poly- | Much, many, excessive | polyuria |
| pulmon- | Lung | pulmonary |
| py(o) | Pus | empyema |
| pyr-, pyro- | Fever, heat | pyrexia |
| ren(o) | Kidney | renal |
| -rrhea | Excessive discharge or flow | rhinorrhea |
| scler(o) | Hard, hardening | atherosclerosis |
| -scope | Instrument used to view | microscope, bronchoscope |
| -spasm | Involuntary contraction | vasospasm, bronchospasm |
| -stomy | Surgical opening | tracheostomy |
| sub- | Under, beneath, below | sublingual, subcutaneous, subcostal |
| tachy- | Fast, rapid | tachypnea |
| thorac(o) | Chest, thorax | thoracotomy |
| thromb(o) | Blood clot | thrombosis, thrombogenic, thrombus |
| thyr(o) | Thyroid | hyperthyroidism |
| -tomy | Incision, cut into | thoracotomy |
| toxi- | Poison | toxic |
| trache- | Trachea, windpipe | tracheostomy |
| trans- | Across, over, through | transdermal, transfusion |
| -trophy | Growth, development | hypertrophy |
| vas(o)- | Blood vessel | vascular, vasospasm |
| ven(o)- | Vein | venipuncture, venous, venopressor |
Medical Imaging
Radiography
- A single barrage of x-rays passes through the body, producing an image of interior structures on x-ray-sensitive film
- Inexpensive with quick results
- Bones appear white; air and hollow structures appear black
- Contrast can be added to make some structures more prominent
Chest X-Ray (CXR)
- The most rapid and utilized study to identify lung issues
Magnetic Resonance Imaging (MRI)
The body is exposed to a high-energy magnetic field and radio waves, which creates patterns read by a computer.
| Pros | Cons |
|---|---|
| Relatively safe | Cannot be used on patients with metal in the body |
| Fine detail of soft tissue | No fine detail for bones |
| Great for distinguishing abnormal from normal tissue |
- Used to detect tumors, artery-clogging fatty plaques, and brain abnormalities
Computed Tomography (CT)
- Uses x-rays to form transverse sectional imaging
- Visualizes soft tissue and organs in detail
- Multiple scans can be assembled to create a 3D image
- Beneficial for screening lung cancers, coronary artery disease, and kidney cancers
Ultrasound
High-frequency sound waves produce an image when they reflect off an object.
- Safe, noninvasive, painless, and uses no dyes
- Most commonly used to visualize a fetus
- Also used for size, location, and actions of organs and blood flow through vessels (Doppler)
Coronary (Cardiac) Computed Tomography Angiography (CCTA)
- An iodine-containing medium is injected into a vein
- X-ray beams create a 3D image of the heart and vessels
- Primary use: identify coronary artery blockage
Positron Emission Tomography (PET)
- A substance is injected into the body and absorbed by tissues
- Used to study the physiology of body structures, such as metabolism in the brain or heart
Endoscopy
- Involves visual exam of the inside of body organs or cavities
- Used for therapeutic and diagnostic purposes
- Example: bronchoscopy
Review
- Anatomy and physiology defined
- Levels of structural organization and body systems
- Characteristics of the living human organism
- Homeostasis and feedback systems
- Basic anatomical terminology and body cavities
- Basic medical terminology
- Medical imaging