Z-disc
/ˈziː dɪsk/
The boundary between sarcomeres in muscle tissue where actin filaments are anchored.
Z-DNA
/ˈziː diː ɛn eɪ/
A left-handed double helical form of DNA, different from the more common right-handed B-DNA.
Z-ligament
/ˈziː ˈlɪɡəmənt/
A rare synonym for the iliofemoral ligament of the hip (the Y-ligament).
Z-line
/ˈziː laɪn/
The squamocolumnar junction where the lining of the esophagus meets the lining of the stomach.
Z-plasty
/ˈziː ˈplæsti/
A surgical technique used to improve the functional and cosmetic appearance of scars by redirecting tension.
Z-track injection
/ˈziː træk ɪnˈdʒɛkʃən/
A technique for intramuscular injection that prevents medication from leaking into the subcutaneous tissue.
Zafirlukast
/zəˈfɪərluːkæst/
An oral leukotriene receptor antagonist used for the maintenance treatment of asthma.
Zaleplon
/ˈzæləplɒn/
A sedative-hypnotic medication used for the short-term treatment of insomnia.
Zeatin
/ˈziːətɪn/
A plant hormone derived from adenine, sometimes studied in regenerative medicine for cell growth properties.
Zeaxanthin
/ˌziːəˈzænθɪn/
A carotenoid pigment found in the retina (macula) that helps protect the eye from light damage.
Zebra body
/ˈziːbrə ˈbɒdi/
Transverse striped lysosomal structures seen in cells under electron microscopy in certain metabolic diseases like Fabry disease.
Zein
/ˈziːɪn/
A group of proteins found in maize, used in pharmaceutical manufacturing for coating pills.
Zeis gland
/zaɪs ɡlænd/
Small sebaceous glands located at the free edge of the eyelids, associated with eyelash follicles.
Zeitgeber
/ˈtsaɪtˌɡeɪbər/
An external cue, such as daylight, that helps regulate the body's internal biological clock.
Zeller's test
/ˈzɛlərz/
A historical laboratory test for the presence of melanin in the urine.
Zenker's necrosis
/ˈzɛŋkərz nɪˈkroʊsɪs/
Severe hyaline degeneration or necrosis of skeletal muscle, historically associated with typhoid fever.
Zenker’s diverticulum
/ˈzɛŋkərz ˌdaɪvərˈtɪkjʊləm/
A pouch that forms at the junction of the lower throat and upper esophagus, causing difficulty swallowing.
Zenker’s fluid
/ˈzɛŋkərz/
A rapid-acting histological fixative used to preserve animal tissues for microscopic study.
Zeosis
/ziːˈoʊsɪs/
The formation of blebs or bubbles on the surface of a cell as it undergoes apoptosis.
Zero-order kinetics
/ˈzɪəroʊ ˈɔːrdər kɪˈnɛtɪks/
A process where the rate of drug elimination is constant regardless of its concentration (e.g., ethanol metabolism).
Zeroing
/ˈzɪəroʊɪŋ/
The process of calibrating a medical monitoring device (like an arterial line) to atmospheric pressure.
Zest
/zɛst/
In psychiatry, a measure of an individual's enthusiasm and energy levels toward life activities.
Zidovudine
/zaɪˈdoʊvjʊˌdiːn/
An antiretroviral medication (AZT) used to treat HIV/AIDS.
Zidovudine (AZT)
/zaɪˈdoʊvjʊˌdiːn/
The first antiretroviral drug approved for the treatment of HIV infection.
Ziehl-Neelsen stain
/ˌziːl ˈniːlsən/
An acid-fast stain used to identify Mycobacterium tuberculosis and other acid-fast organisms.
Zinc
/zɪŋk/
An essential trace element necessary for immune function, wound healing, and DNA synthesis.
Zinc deficiency
/zɪŋk dɪˈfɪʃənsi/
A nutritional condition causing growth retardation, hair loss, and delayed wound healing.
Zinc oxide
/zɪŋk ˈɒksaɪd/
A white powder used in ointments to treat skin irritations and as a physical sunblock.
Zinc pyrithione
/zɪŋk ˌpaɪrɪˈθaɪoʊn/
An antifungal and antibacterial agent commonly used in over-the-counter dandruff shampoos.
Ziprasidone
/zɪˈpræsɪdoʊn/
An atypical antipsychotic used to treat schizophrenia and bipolar disorder.
Zirconium
/zərˈkoʊniəm/
A metal used in dentistry for high-strength crowns and bridges due to its biocompatibility.
Zollinger-Ellison syndrome
/ˈzɒlɪndʒər ˈɛlɪsən/
A condition in which tumors in the pancreas or duodenum cause the stomach to produce too much acid.
Zolmitriptan
/ˌzoʊlmɪˈtrɪptæn/
A medication (triptan) used for the acute treatment of migraine attacks.
Zolpidem
/ˈzɒlpɪdɛm/
A sedative-hypnotic drug used for the short-term treatment of sleeping problems; brand name Ambien.
Zona
/ˈzoʊnə/
In anatomy, a region or area with distinct characteristics (e.g., Zona glomerulosa of the adrenal gland).
Zona fasciculata
/ˈzoʊnə fəˌsɪkjʊˈlɑːtə/
The middle layer of the adrenal cortex that produces glucocorticoids like cortisol.
Zona glomerulosa
/ˈzoʊnə ɡləˌmɛrjʊˈloʊsə/
The outermost layer of the adrenal cortex that produces mineralocorticoids (aldosterone).
Zona pellucida
/ˈzoʊnə pəˈluːsɪdə/
The thick, transparent membrane surrounding a mammalian ovum (egg) before implantation.
Zona reticularis
/ˈzoʊnə rəˌtɪkjʊˈlɛərɪs/
The innermost layer of the adrenal cortex that produces androgens.
Zonal
/ˈzoʊnəl/
Pertaining to a specific zone or area within an organ or tissue.
Zonula adherens
/ˈzɒnjʊlə ædˈhɪərɛnz/
A type of cell junction in epithelial tissues that helps hold cells together.
Zonula occludens
/ˈzɒnjʊlə əˈkluːdɛnz/
A tight junction; the area where two cell membranes are joined together to form an impermeable barrier.
Zonule of Zinn
/ˈzɒnjuːl əv zɪn/
A ring of fibrous strands connecting the ciliary body with the crystalline lens of the eye.
Zonulitis
/ˌzɒnjʊˈlaɪtɪs/
Inflammation of the zonule of the eye.
Zonulolysis
/ˌzɒnjʊˈlɒlɪsɪs/
The enzymatic dissolution of the zonule of the lens during cataract surgery.
Zoonosis
/ˌzoʊəˈnoʊsɪs/
An infectious disease that has jumped from a non-human animal to humans.
Zoonotic
/ˌzoʊəˈnɒtɪk/
Relating to a disease that can be transmitted from animals to humans.
Zopiclone
/ˈzɒpɪkloʊn/
A nonbenzodiazepine hypnotic used in the treatment of insomnia.
Zoster
/ˈzɒstər/
Short for Herpes Zoster; the virus that causes shingles.
Zoster sine herpete
/ˈzɒstər ˈsiːneɪ ˈhɜːrpɛtiː/
Pain caused by shingles without the typical visible skin rash.
Zosteroid
/ˈzɒstərɔɪd/
Resembling shingles, particularly in the distribution of skin lesions along a nerve path.
Zuckerkandl, Organ of
/ˈtsʊkərˌkændəl/
A chromaffin body derived from neural crest cells located at the bifurcation of the aorta.
Zygapophysial joint
/ˌzaɪɡəpəˈfɪziəl/
The facet joint; a synovial joint between the superior and inferior articular processes of vertebrae.
Zygapophysis
/ˌzaɪɡəˈpɒfɪsɪs/
The articular process of a vertebra that forms a joint with the adjacent vertebra.
Zygodactyly
/ˌzaɪɡəˈdæktɪli/
A form of syndactyly where two or more fingers or toes are fused.
Zygoma
/zaɪˈɡoʊmə/
The cheekbone; also known as the zygomatic bone.
Zygoma fracture
/zaɪˈɡoʊmə ˈfræktʃər/
A break in the cheekbone, often occurring as part of a tripod fracture in facial trauma.
Zygomatic arch
/ˌzaɪɡəˈmætɪk ɑːrtʃ/
The bony arch formed by the cheekbone and the temporal bone.
Zygomaticofacial nerve
/ˌzaɪɡəmætɪkoʊˈfeɪʃəl/
A branch of the maxillary nerve that provides sensation to the skin of the cheek.
Zygomaticotemporal nerve
/ˌzaɪɡəmætɪkoʊˈtɛmpərəl/
A branch of the maxillary nerve that provides sensation to the skin of the temple.
Zygomaticus major
/ˌzaɪɡəˈmætɪkəs ˈmeɪdʒər/
A muscle of facial expression that draws the angle of the mouth up and back (the 'smiling muscle').
Zygomaticus minor
/ˌzaɪɡəˈmætɪkəs ˈmaɪnər/
A muscle of facial expression that elevates the upper lip.
Zygomycosis
/ˌzaɪɡəmaɪˈkoʊsɪs/
A rare but serious fungal infection caused by molds of the order Mucorales.
Zygote
/ˈzaɪɡoʊt/
The cell formed by the fusion of a sperm and an egg; a fertilized ovum.
Zygote intrafallopian transfer (ZIFT)
/ˈzaɪɡoʊt/
An infertility treatment where a fertilized egg is placed into the fallopian tube.
Zymase
/ˈzaɪmeɪs/
An enzyme complex found in yeast that catalyzes the fermentation of sugar into alcohol.
Zymogen
/ˈzaɪmədʒən/
An inactive substance that is converted into an enzyme when activated by another enzyme.
Zymology
/zaɪˈmɒlədʒi/
The study of fermentation and its medical/biochemical applications.
Zymolysis
/zaɪˈmɒlɪsɪs/
The action of an enzyme or fermentation process.
Zymoprotein
/ˌzaɪməˈproʊtiːn/
A protein that possesses enzymatic properties.