ileocecal (il-ē-ō-SĒ-kăl): Pertaining to the ileum and cecum.

ileostomy (IL-ē-OS-tŏ-mē): Creation of an artificial opening in the ileum.

iliofemoral (il-ē-ō-FEM-ŏ-răl): Pertaining to the ilium and femur.

immune (i-MŪN): Resistant to specific pathogens.

immune system (i-MŪN SIS-tĕm): Series of barriers, cells, and soluble mediators that combine to response to infections of the body with pathogenic organisms.

immunity (im-Ū-nĭt-ē): After an infection, memory cells remain in the body for a long time and can very quickly mount an immune response against the same pathogen if it tries to re-infect. This protects us from getting diseases from the same pathogen over again.

immunodeficiency (im-yŭ-nō-dĕ-FISH-ĕn-sē): Deficient immune response caused by immune system dysfunction brought on by disease or immune suppressive drugs.

immunological memory (im-yŭ-NOL-ŏ-jē- kăl MEM-ŏ-rē): Ability of the adaptive immune response to mount a stronger and faster immune response upon re-exposure to a pathogen.

Immunologist (ĭm-ū-NŎL-ō-jĭst): Specialist who studies and treats immune system disorders.

immunology (im-yŭ-NOL-ŏ-jē): Study of disorders of the immune system.

implantable cardioverter defibrillator (im-plan″TĀ-shŏn KĂR-dē-ō-vĕr-tĕr dē-FIB-rĭ-lāt-ŏr): An electronic implant that provides an automatic shock to convert a dangerous heart rhythm to a normal heart rhythm.

incise, incision (in-SĪZ, in-SIZH-ŏn): Surgical cut into or wound produced by a sharp instrument.

incision and drainage (in-SIZH-ŏn & DRĀN-ăj): Surgical cut made to allow the free flow of fluids from a lesion, wound, or cavity.

incontinence (in-KONT-ĭn-ĕns): Inability to control the bladder and/or bowels.

induction (in-DŬK-shŏn): The process of bringing on or starting labour. This may be done with a membrane sweep or through the use of IV oxytocin.

induration (ĬN-dū-rā-shun): A firm, raised reddened patch of skin.

infection (in-FEK-shŏn): Invasion by disease-causing organisms.

inferior (or caudal) (in-FĒR-ē-ŏr): Describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column).

inferior vena cava (in-FĒR-ē-ŏr VĒ-nă KĀ-vă): One of the two largest veins in the body. It carries deoxygenated blood from the torso and legs back to the heart.

infertility (in-fĕr-TIL-ĭt-ē): Inability to achieve pregnancy.

inflammation (in-flă-MĀ-shŏn): Basic innate immune response characterized by heat, redness, pain, and swelling.

influenza (flu) (in-floo-EN-ză): Highly contagious viral infection effecting the respiratory tract.

inguinal canal (ING-gwĭ-năl kă-NAL): Opening in abdominal wall that connects the testes to the abdominal cavity.

initial segment (ĭn-ĬSH-ăl SEG-mĕnt): First part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated.

innate immune response (ĭn-NĀT i-MŪN ri-SPONS): Rapid but relatively nonspecific immune response.

inspiration (ĭn-spĭr-Ā-shŭn): Inhalation or process of breathing air into the lungs.

integration (int-ĕ-GRĀ-shŏn): Nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response.

interatrial septum (nt-ĕr-RĀ-trē-ăl SEP-tŭm): The wall separating the right and left atria.

intercellular (ĭn-tĕr-SĔL-ū-lăr): Between cells.

intercostal (int-ĕr-KOS-tăl): Pertaining to between the ribs.

interferons (int-ĕr-FĒR-on): Early induced proteins made in virally infected cells that cause nearby cells to make antiviral proteins.

interictal (ĭn-tĕr-ĬK-tăl): Occurs between seizures or attacks.

interstitial (in-tĕr-STISH-ăl): Between cells of the tissues, often used interchangeably with ‘intercellular’.

interstitial fluid (in-tĕr-STISH-ăl FLOO-ĭd): Fluid that has leaked out of blood capillaries into the tissue spaces.

interstitial space (in-tĕr-STISH-ăl spās): Spaces between individual cells in the tissues.

interventricular septum (int-ĕr-ven-TRIK-yŭ-lăr SEP-tŭm): The wall of myocardium that separates the right and left ventricles.

intervertebral (ĭn-tĕr-VĔRT-ĕ-brĕl): Pertaining to between the vertebrae.

intracellular (ĭntră-SĔL-ū-lăr): Inside the cell membrane or within the cell.

intracerebral (in-tră-SER-ĕ-brăl): Pertaining to within the cerebrum.

intracranial (in-tră-KRĀ-nē-ăl): Pertaining to within the cranium.

intradermal (in-tră-DĔR-măl): Pertaining to within the skin.

intramuscular (in-tră-MŬS-kyŭ-lăr): Pertaining to within the muscle.

intraocular (in-tră-OK-yŭ-lăr): Pertaining to within the eye.

intrapartum (in-tră-PART-ŭm): Within (during) labour and delivery.

intravenous (in-tră-VĒ-nŭs): Pertaining to within the vein.

in vitro fertilization (IVF) (in VĒ-trō fĕrt-ĭl-ĭ-ZĀ-shŏn): A process where the ova is fertilized outside the body and then implanted into the uterus.

iridectomy (ir-ĭ-DEK-tŏ-mē): Excision of (part of) the iris.

iridoplegia (ir-ĭ-dō-PLĒ-j(ē-)ă, īr): Paralysis of the iris.

iridotomy (ĭr-ĭ-DŎT-ō-mē): Incision into the iris.

iritis (ī-RĪT-ĭs): Inflammation of the iris.

ischemia (is-KĒ-mē-ă): Insufficient blood and oxygen to cells of an organ. These cells are starving for oxygen, but they are still alive.

ischemic (is-KĒ-mē-ă): Ischemia is a condition in which cells receive insufficient amounts of blood and oxygen.

ischemic stroke (is-KĒ-mē-ă strōk): Disruption of blood flow to the brain because blood cannot flow through blood vessels as a result of a blockage or narrowing of the vessel.

ischiofibular (is-kē-ō-FIB-yŭ-lăr): Pertaining to the ischium and fibula.

isocoria (ī-sō-KŌ-rē-ă): Condition of equal pupils.