ANZCA Primary Definitions
Updated 2025
Term - ANSWER✔✔-Definition
A-a Gradient - ANSWER✔✔-The numerical difference between ideal alveolar PAO2
and PaO2. An index of the amount of V/Q inequality and shunting which is present.
Absolute Humidity - ANSWER✔✔-Mass of H2O vapour in a given volume of air mg/L
Absorption - ANSWER✔✔-The rate at which a drug leaves its site of administration and
the extent to which this occurs.
Acid - ANSWER✔✔-A proton (or H+ ion) donor
Acidaemia - ANSWER✔✔-Arterial blood pH < 7.35 or [H+] > 44 nmol/L
Acidosis - ANSWER✔✔-An abnormal process or condition which tends to lower
arterial pH if there are inadequate secondary changes in response to the primary
disease process. Two types: Respiratory and metabolic.
Acquired Immunity - ANSWER✔✔-"The delayed onset but specific and memory
immunity after the first line innate immunity is breached. First exposure allows
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,identification and learning, and the second exposure initiates quick mobilisation of
lymphocytes. Major components: Humoral Immunity (B lymphocytes producing
specific antibodies), and Cellular Immunity (T lymphocytes)"
Active Tension (Muscle) - ANSWER✔✔-Active tension: the difference between passive
and total tension
Activity (Acid-Base) - ANSWER✔✔-The effective concentration of a substance in a
reacting system
Adiabetic Heat - ANSWER✔✔-Heat produced when a gas is compressed
Affinity - ANSWER✔✔-"Avidity with which a drug binds to a receptor (analogous to
potency), or ability to bind to a receptor and form a stable complex. Inverse of Kd."
Afterload - ANSWER✔✔-Physiological def: Force restricting muscle fibre shortening or
weight/load that a contracting muscle must overcome prior to shortening. <br>Clinical
def: The impedance to the ejection of blood from the left ventricle into the aorta
Aging - ANSWER✔✔-"A normal physiological process of degeneration beginning
around age 30 and proceeding at a variable rate with obvious changes becoming
apparent at around age 60, and the end point being death."
Agonist - ANSWER✔✔-Binds to receptor to produce responses that may be excitatory
or inhibitory. Partial agonist displays intermediate efficacy.
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,Airway Resistance - ANSWER✔✔-"The resistance to the movement of air through the
airways. It is dependent on lung volume, bronchial smooth muscle tone, bronchial
mucosal engorgement, density and viscosity of the inspired gas, and the respiratory
rate."
Alkalaemia - ANSWER✔✔-Arterial blood ph > 7.45 or [H+] < 36 mmol/L
Alkalosis - ANSWER✔✔-An abnormal process or condition which tends to raise arterial
pH if there are inadequate secondary changes.
Allodynia - ANSWER✔✔-Pain due to a stimulus which does not normally provoke
pain. Stimulation of A beta fibres causes pain.
Alveolar Dead Space - ANSWER✔✔-Part of inspired gas which passes through the
anatomical dead space and enters the alveoli but is not effective in gas exchange given
impaired perfusion.
Alveolar Ventilation - ANSWER✔✔-"Effective ventilation of the alveoli, where gas
exchange with the blood takes place."
Ampere - ANSWER✔✔-One Coulomb per second
Amplitude Linearity - ANSWER✔✔-Amplifications of the signal should be equal
throughout the entire signal range to prevent distortion.
Anabolism - ANSWER✔✔-Synthesis of cellular macromolecules
Anaesthesia - ANSWER✔✔-Without sensation.
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, Analgesia - ANSWER✔✔-Absence of pain in response to stimulation which would
normally be painful.
Analog Signal - ANSWER✔✔-"A <b>continuous</b> signal for which the time varying
feature (variable) of the signal is a representation of some other time varying quantity,
i.e., analogous to another time varying signal."
Anaphylactoid Reaction - ANSWER✔✔-"Clinically indistinguishable from anaphylaxis
but caused by complement activation or direct histamine release from mast cells. *c.f.
Anaphylaxis is a clinical syndrome produced by IgE type I hypersensitivity resulting
from antigen-antibody reaction at surface of mast cells. The syndrome manifests as red
rash/flush, bronchospasm, collapse, angioedema, GIT symptoms. Requires prior
exposure to antigen."
Anaphylatoxins - ANSWER✔✔-C3a and C5a which bind specific receptors on mast cells
and basophils causing degranulation.
Anaphylaxis - ANSWER✔✔-"A clinical syndrome produced by IgE type I
hypersensitivity resulting from antigen-antibody reaction at surface of mast cells. The
syndrome manifests as red rash/flush, bronchospasm, collapse, angioedema, GIT
symptoms. Requires prior exposure to antigen."
Anatomical Dead Space - ANSWER✔✔-The internal volume of the conducting airways
or that part of the inspired TV which is expired unchanged.
Anion - ANSWER✔✔-Negatively charged ion.
COPYRIGHT © 2025 ALL RIGHTS RESERVED
Updated 2025
Term - ANSWER✔✔-Definition
A-a Gradient - ANSWER✔✔-The numerical difference between ideal alveolar PAO2
and PaO2. An index of the amount of V/Q inequality and shunting which is present.
Absolute Humidity - ANSWER✔✔-Mass of H2O vapour in a given volume of air mg/L
Absorption - ANSWER✔✔-The rate at which a drug leaves its site of administration and
the extent to which this occurs.
Acid - ANSWER✔✔-A proton (or H+ ion) donor
Acidaemia - ANSWER✔✔-Arterial blood pH < 7.35 or [H+] > 44 nmol/L
Acidosis - ANSWER✔✔-An abnormal process or condition which tends to lower
arterial pH if there are inadequate secondary changes in response to the primary
disease process. Two types: Respiratory and metabolic.
Acquired Immunity - ANSWER✔✔-"The delayed onset but specific and memory
immunity after the first line innate immunity is breached. First exposure allows
COPYRIGHT © 2025 ALL RIGHTS RESERVED
,identification and learning, and the second exposure initiates quick mobilisation of
lymphocytes. Major components: Humoral Immunity (B lymphocytes producing
specific antibodies), and Cellular Immunity (T lymphocytes)"
Active Tension (Muscle) - ANSWER✔✔-Active tension: the difference between passive
and total tension
Activity (Acid-Base) - ANSWER✔✔-The effective concentration of a substance in a
reacting system
Adiabetic Heat - ANSWER✔✔-Heat produced when a gas is compressed
Affinity - ANSWER✔✔-"Avidity with which a drug binds to a receptor (analogous to
potency), or ability to bind to a receptor and form a stable complex. Inverse of Kd."
Afterload - ANSWER✔✔-Physiological def: Force restricting muscle fibre shortening or
weight/load that a contracting muscle must overcome prior to shortening. <br>Clinical
def: The impedance to the ejection of blood from the left ventricle into the aorta
Aging - ANSWER✔✔-"A normal physiological process of degeneration beginning
around age 30 and proceeding at a variable rate with obvious changes becoming
apparent at around age 60, and the end point being death."
Agonist - ANSWER✔✔-Binds to receptor to produce responses that may be excitatory
or inhibitory. Partial agonist displays intermediate efficacy.
COPYRIGHT © 2025 ALL RIGHTS RESERVED
,Airway Resistance - ANSWER✔✔-"The resistance to the movement of air through the
airways. It is dependent on lung volume, bronchial smooth muscle tone, bronchial
mucosal engorgement, density and viscosity of the inspired gas, and the respiratory
rate."
Alkalaemia - ANSWER✔✔-Arterial blood ph > 7.45 or [H+] < 36 mmol/L
Alkalosis - ANSWER✔✔-An abnormal process or condition which tends to raise arterial
pH if there are inadequate secondary changes.
Allodynia - ANSWER✔✔-Pain due to a stimulus which does not normally provoke
pain. Stimulation of A beta fibres causes pain.
Alveolar Dead Space - ANSWER✔✔-Part of inspired gas which passes through the
anatomical dead space and enters the alveoli but is not effective in gas exchange given
impaired perfusion.
Alveolar Ventilation - ANSWER✔✔-"Effective ventilation of the alveoli, where gas
exchange with the blood takes place."
Ampere - ANSWER✔✔-One Coulomb per second
Amplitude Linearity - ANSWER✔✔-Amplifications of the signal should be equal
throughout the entire signal range to prevent distortion.
Anabolism - ANSWER✔✔-Synthesis of cellular macromolecules
Anaesthesia - ANSWER✔✔-Without sensation.
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, Analgesia - ANSWER✔✔-Absence of pain in response to stimulation which would
normally be painful.
Analog Signal - ANSWER✔✔-"A <b>continuous</b> signal for which the time varying
feature (variable) of the signal is a representation of some other time varying quantity,
i.e., analogous to another time varying signal."
Anaphylactoid Reaction - ANSWER✔✔-"Clinically indistinguishable from anaphylaxis
but caused by complement activation or direct histamine release from mast cells. *c.f.
Anaphylaxis is a clinical syndrome produced by IgE type I hypersensitivity resulting
from antigen-antibody reaction at surface of mast cells. The syndrome manifests as red
rash/flush, bronchospasm, collapse, angioedema, GIT symptoms. Requires prior
exposure to antigen."
Anaphylatoxins - ANSWER✔✔-C3a and C5a which bind specific receptors on mast cells
and basophils causing degranulation.
Anaphylaxis - ANSWER✔✔-"A clinical syndrome produced by IgE type I
hypersensitivity resulting from antigen-antibody reaction at surface of mast cells. The
syndrome manifests as red rash/flush, bronchospasm, collapse, angioedema, GIT
symptoms. Requires prior exposure to antigen."
Anatomical Dead Space - ANSWER✔✔-The internal volume of the conducting airways
or that part of the inspired TV which is expired unchanged.
Anion - ANSWER✔✔-Negatively charged ion.
COPYRIGHT © 2025 ALL RIGHTS RESERVED
