Anatomy and Physiology

Abscess

A swollen area contaning puss.

Accretion

An increase in size of a body part, due to accumulation of deposits, such as salts.

ACE inhibitor

Angiotensin Converting Enzyme inhibitor: for treatment of hypertension and congestive heart failure, decreasing blood vessel tension and blood volume.
Examples: Captopril, Cilazapril, Enalapril, Fosinopril, Imidapril, Lisinopril, Moexipril, Perindopril, Quinapril, Ramipril and Trandolapril.

Acetone

Colourless inflammable liquid, with a distinctive smell, occurring in diabetics.

Acetylcholine (ACh)

Parasympathetic neurotransmitter, stored in synaptic vesicles within nerve terminals, released by exocytosis (nerve impulses). Binds with nicotinic receptors on cholinergic nerve neurons in the motor end plate of the neuromuscular junction. Nicotinic effect is depolarization, causing muscle contraction. ACh also produces muscarinic effects, which may be countered by antimuscarinic drugs, such as Glycopyrolate or Atropine. Acetylcholine is degraded by cholinesterase.

Acid reflux

Stomach acid moving into the oesophagus through a faulty muscle in the oesophagus.

Acquired aortic valve disease

Abnormalities of the aortic valve which develop with age.

Adenitis

Inflammation of a gland or lymph node.

Adenosine

An anti-arhythmic, which slows down electrical conduction.

Adipose

Containing fat.

Adrenaline

A positive inotropic hormone secreted by the adrenal glands, and which stimulates the sympathetic nervous system, and increases the force of cardiac contractions. Pharmacological Adrenaline is used in many emergency situations, such as cardiac arrest and acute anaphylaxis.

Agonal rhythm

Asystole with occasional P wave or QRS complex.

Aldosterone

The main hormone involved in potassium regulation.

Alimentary

Relating to food or nutrition.

Allergic reactions

Allergy is an abnormal reaction to naturally occurring protein allergens. When an allergic person is exposed to those allergens, the white blood cells (B-lymphocytes) produce anti-bodies which stick to the surface of allergy cells, so the body can respond when next exposed to allergens - a process known as sensitisation. The most common allergens are: pollen, mould, dust mites, medicines, animal fur.

Allergy treatments:
Nasal	Sodium Cromoglicate, Levocabastine, Decongestants, Corticosteroids (severe cases).
Eye drops	Sodium Cromoglicate (eg, Opticam), Nedocromal Sodium (eg, Rapitil), Levocabastine.
Injections	Allergy inducing agents to create tolerance (hyposensitisation).
Intramuscular	Long acting steroids.

Minor allergies are treated with anti-histamines, such as Levocabastine.

Alveolar Ventilation

The amount of air which reaches the alveoli, and is available for gas exchange with the blood, per unit time.

Anaplasia

Changes to the character of cells, as in tumourous tissue.

Anastamosis

A surgical connection between two structures, typically tubular, such as blood vessels or intestinal sections.

Anatomical dead space

The conducting airways which do not take part in gas exchange (mouth, nose, pharynx, larnyx, trachea), but convect gases between the atmosphere/gas supply and alveoli.

Aneurysm

An abnormality of a blood vessel, where the vessel wall is weakened, and expands or balloons into a blood filled sac.

Angina

Tight sensation of strangling or pain. Angina Pectoris: Cardiac pain caused by insufficient blood supply to the heart.

Angioedema

Swelling of the deeper layers of the skin, caused by a build-up of fluid. Symptoms can affect any part of the body, but swelling usually affects the: eyes, lips, genitals, hands, or feet. This condition is often accompanied by urticaria (hives).

Angiogenesis

The formation of new blood vessels.

Angiospasm

A spasm which constricts blood vessels.

Angiotensin

A polypeptide, formed in the blood through the action of renin on plasma globulus, which increases blood pressure.

Anoxia

Lack of oxygen supply to the organs/tissues.

Antibody

A Y shaped protein, produced in the blood, and present on the surface of B cells, in response to the presence of antigens. Antibodies attach to antigens on infectious organisms, then either destroy them, or render them harmless.

Anticoagulants

Antidiuretic Hormone (ADH, Vasopressin)

Peptide hormone secreted by the posterior lobe of the pituitary gland. ADH causes reabsorption of water in the renal tubules, with consequent reducion in urine output. In larger doses, ADH causes constriction of plain muscle, which increases peripheral vascular resistance, resulting in increased arterial blood pressure. Used in the treatment of diabetes inspidus.

Antigen

Antibody generator A substance which evokes the production of one or more antibodies. More

Anti platelet agents

For example: NSAIDs, aspirin, clopidogrel, might contribute to increased surgical blood loss, and should be stopped before surgery, to allow platelet function to return to normal.

Aorta

The largest artery in the body, which carries oxygenated blood from the heart, for systemic circulation.

Apnoea

Cessation of breathing.

Apraxia

The inability to make proper movements.

Arrhythmia

Variation from normal rhythm, such as that which can occur in the heart.

Arrhythm type	Description
Ventricular tachycardia	Abnormally fast beating of the ventricles.
Ventricular fibrillation	Erratic fluttering of the ventricles.
Atrial fibrillation	A supraventricular arrhythmia: Palpitation - fast beating of the atria.

Possible symptoms...

Chest pain
Shortness of breath
Lightheadedness
Dizziness
Fainting

Arterial Blood Gas

Analysis of arterial blood components, such as acid-base balance and oxygenation:

Base Excess	A negative or positive excessive level of bicarbonate (normal: -2 to +2 mEq/l)
HCO₃	Level of bicarbonate; lower than 22 mEq/l means acidosis; greater than 26 is alkalosis
pCO₂	Partial pressure of CO₂ dissolved in arterial blood
pH	Measurement of hydrogen ions(H+) in the blood (7.35 to 7.45)
PO	Partial pressure of dissolved O₂ in arterial blood
SaO₂	Saturation level of arterial free oxygen

Arterial Pressure

Mean arterial pressure is defined as diastolic + 1/3 (systolic - diastolic).

Arterial Thrombosis

A blood clot which develops in an artery. Arterial thrombosis is usually associated with atherosclerosis, which is hardening and narrowing of the arteries. A heart attack occurs when a blood clot blocks the arteries leading to the heart, inhibiting the blood supply. A stroke occurs when a blood clot blocks an artery in the brain.

Ascites

An accumulation of serous fluid in the peritoneal cavity.

Atrial Flutter

Rapid contractions of the Atria, 240-350 beats/minute, often accompanied by AV block.

Axon

Long thin cylindrical projection of a neuron, which propogates nerve impulses to another neuron, gland cell, or muscle fibre.

Bacteraemia

Bactreria in the bloodstream.

Backward heart failure

Pulmonary and peripheral oedema.

Barotrauma

An injury caused by an excess of relative pressure. For example, if an oxygen flush is made during the ventilator inspiratory phase, the excess gas in the circuit (including lungs) cannot be vented, because the ventilator relief valve is closed. The result of which could be a "burst lung".

Bifurcation

The junction where a vessel divides into two branches.

Bigeminy

Two pulse beats which occur at the same time.

Biofilm

A thin layer of microorganisms adhering to the surface of a structure.

Blood

Blood is a suspension of cells in plasma. Cells are 45% of total blood volume, with the remaining 55% being plasma.
Outline || Physiology || Products || Profiles || Clotting tests || INR ||
Transfusion - AAGBI || Main tests || BM monitoring || Tutorial

Blood gases

Inspired gases, such as air or nitrous oxide, are distributed throughout the body via arterial circulation. The component gases have partial pressures (P), relative to ambient pressure, which are determined by their particular proportions. At mean sea level, 100% oxygen has a mean partial pressure of 101 kilo Pascals (kPa).

Of relevance to the patient´s condition, is the arterial oxygen partial pressure (PaO₂). In a healthy patient, inspired oxygen partial pressure should be 10 kPa higher than arterial oxygen partial pressure. If the inspired difference is greater than 10 kPa, the patient may be suffering from pulmonary disease. This is the "rule of ten".

For example, if the patient is breathing 40% oxygen, which has a partial pressure of oxygen (PaO₂) of approximately 40 kPa, the arterial oxygen partial pressure (PaO₂) should be 30 kPa.

Blood oxygen terms

Symbol	Description
PAO₂	Partial pressure of oxygen in the Alveolar
PaO₂	Partial Pressure of oxygen in arterial Blood - normal range is 75-100 mm/Hg
SaO₂	Arterial haemoglobin oxygen saturation - by direct measurement (arterial blood gas sample)
SpO₂	Indirect measurement of blood oxygen content (pulse oximetry)

Blood sugar

Blood sugar (glucose) levels refer to the amount of glucose in the blood - the serum glucose level. The glucode level is expressed as millimoles per litre (mmol/L), and is stable for non diabetics; around 4 - 8 mmol/L. The blood sugar level is lowest after sleeping, and highest after a meal.
The system for testing blood sugar was developed by Boehringer Mannheim, now Roche, hence the name - BM. Testing See also Diabetes

Body Mass Index (BMI)

Weight (kg) divided by the square of the height (m). A BMI of 30 is considered obese.

Bronchitis

Inflammation of the bronchi, the tubes (airways) which carry oxygen from the air through the lungs. The inflammation increases mucus production in the airways, producing phlegm, and a cough reflex.

Bronchus

Plural bronchi; The left and right main bronchi diverge from the bifurcation of the trachea, and supply the left and right lungs respectively.

Eparterial Bronchus

The right lung is distinguished by the Eparterial Bronchus, also known as the right superior lobar bronchus, which is a branch of the right main bronchus, and occurs at about 1 inch (2.5cm) from the bifurcation of the trachea, at the secondary carina.
The Eparterial Bronchus supplies the superior lobe of the right lung, and is the most superior of all secondary bronchi. It arises above the level of the pulmonary artery and, for this reason, is known as the eparterial bronchus. (Distributions inferior to the pulmonary artery are termed hyparterial.)

Brugada syndrome

A serious heart condition which can cause fainting and arrhythmias.

Bundle of Hiss

Cardiac muscle which conducts atrioventricular node impulses to the septum, and then divides to connect with the ventricles.

Bursa

A sac containing fluid, such as in a joint.

Caecum

The wide section of the large intestine, in the lower right abdomen, where the large and small intestines join.

Calculus

Insoluble crystallised matter which forms forms, for example, within the gallbladder, urinary bladder, and kidneys.

Capillary

The blood vessel between an arteriole and a venule, which carries nutrients to the tissues.

Carbon dioxide

CO₂ is a heavy, colourless, odourless, incombustible, and corrosive gas; a compound of carbon and oxygen, formed during respiration, combustion, and organic decomposition (also called carbonic acid gas).

Carbonic acid

A weak acid which is created when carbon dioxide is dissolved in water, resulting in the chemical formula H₂CO₃. When the acid dissociates, or gives up a hydrogen ion, the resulting molecule is called a bicarbonate ion.
In physiology, carbonic acid is described as volatile acid or respiratory acid, because it is the only acid excreted as a gas by the lungs.
Also, a solution of carbon dioxide in water.

Cardiac compression

Pressure on the heart caused by fluid in the pericardium.

Cardiovascular System

Pertaining to the heart and blood vessels. More

Carina

The point at which the Trachea divides into the right and left main bronchii.

Carpus

Wrist.

Central Nervous System

The brain and spinal cord.

Cerebrospinal fluid (CSF)

A clear and colourless fluid, produced in the choroid plexus of the brain. The CSF lies in the subarachnoid space (between the arachnoid mater and the pia mater) and in the ventricular system around and inside the brain and spinal cord. The CSF cushions the spine and brain against shock. A CSF test can be used to measure spinal fluid pressure. Normal CSF glucose level is 50 - 80 mg/100 mL, or > 2/3 of blood sugar level.

Chalasia

Relaxation of the eosophageal muscles, resulting in regurgitation.

Cholinergic

Refers to neurons which release the neurotransmitter Acetylcholine, and those receptors to which Acetylcholine binds.

Cholinesterase (acetylcholinesterase)

An enzyme which breaks down Acetylcholine neurotransmitter hormones into choline and acetyl coenzyme A. Found in the synaptic cleft, the gap between nerve cells, through which, information flows.

Chronic Obstructive Pulmonary Disease (COPD)

Chronic obstructive pulmonary disease refers to chronic bronchitis and emphysema, diseases of the lungs in which the airways become narrowed. This narrowing results in reduced flow of air to and from the lungs, causing shortness of breath, and is a condition which gets progressively worse. COPD is caused by noxious particles or gas - most commonly from smoking - which trigger an abnormal inflammatory response in the lung.

The inflammatory response in the larger airways is known as chronic bronchitis, which is clinically diagnosed when the sufferer regularly coughs up sputum. In the alveoli, the inflammatory response causes emphysema.

The natural course of COPD is characterised by occasional sudden worsening of symptoms, called acute exacerbations, most of which are caused by infection or air pollution. Image

Chvostek's sign

Spasm of the facial muscles.

Chyme

Semi-liquid mix of food and gastric juice, formed in the stomach.

Coagulopathy

An abnormality in the blood clotting process.

Coeliac

Referring to the abdomen.

Compartment Syndrome

An increased level of pressure within a confined space of the body, typically fascial compartments. Affected compartments can be in the hand, arm, buttocks, leg (especially below the knee), foot, and abdomen. Emergency treatment is by fasciotomy - where the fascia is cut to relieve pressure.

Condyle

The rounded end of a bone, which articulates with another.

Contusion

Bruising: a superficial injury produced by impact, and where the skin is unbroken.

Convulsion

Involuntary contraction of a muscle.

Coronary artery bypass grafting (CABG)

A procedure to treat narrowing (stenosis) of the coronary arteries, by creating bypasses around the obstructions, with arteries or veins from elsewhere in the body, thereby improving blood flow to the heart.

Cricoid cartilage

Ring shaped cartilage, at the lower end of the larynx, inferior to the thyroid cartilage and cricothyroid membrane. The Cricoid is the only complete ring of cartilage in the respiratory system.

Croup

Acute obstruction of the larynx, caused by allergy, infection, or new growth.

Cruciate

Cross shaped.

Cyanosis

Bluish tinge to skin and mucous membranes.

Cryoprecipitate

A precipitate which results from cooling. The cryoprecipitate from fresh plasma is rich in Factor VIII, and is used to treat haemophiliacs.

Cutaneous

Pertaining to the skin.

Cyanosis

Bluish tinge to skin and mucous membranes.

Dead space

Part of the airway where gas is not available for exchange.

Débridement

Removal of injured tissue and foreign matter from a wound.

Deep Vein Thrombosis (DVT)

A blood clot in a lower limb vein, indicated by local pain and swelling. The thrombus can be caused by sustained immobility, such as after a long flight.

The thrombus may travel up the leg to the more proximal veins in the thigh and pelvis, forming Popliteal and Ileofemoral thrombosis. A proximal vein thrombosis givea a higher risk (50%) of pulmonary embolus, which can be fatal.

To prevent extension, reccurence, and embolisation, Heparin is given for immediate effect, and Warfarin for the medium to long term. Mechanical prophylaxis is by means of compression stockings and intermittent pneumatic compression cuffs (Flowtrons).

Dendrite

(Greek: Little trees) Nerve fibre process which receives nerve impulses, and provides signal input to the neuron.

Dermatome

An area of skin which is supplied by a single spinal nerve. Each nerve relays sensation from it's region of skin to the brain. Pain in a dermatome, without the associated heat of infection, can indicate damage to the spine.

Diabetes

A condition where the level of glucose in the blood is too high. More

Duodenum

The initial part of the small intestine, between the stomach and jejenum.

Dyspnoea

Laboured or difficult breathing.

Dysuria

Difficulty in passing urine.

Ecchymosis

Bruising

Eclampsia

Hypertensive disorder and toxaemia of pregnancy: an acute and life-threatening complication, characterized by the appearance of seizures, usually in a patient who has developed pre-eclampsia (hypertension and fluid retention). Patients will, typically, show signs of pregnancy induced hypertension, before the onset of eclampsia (eclamptic convulsion). Other cerebral signs may precede the convulsion, for example: nausea, vomiting, headache, and cortical blindness. Organ symptoms may also be present, including abdominal pain, liver failure, pulmonary oedema, and oliguria.
Babyloss reference.

Effusion

Liquid discharge from a cavity.

Electrolytes

Electrolytes, such as bicarbonate, chloride, potassium, and sodium, become ions in solution, thus effecting the electrical conduction.

Embolism

Obstruction of a blood vessel by a substance which has moved through the circulatory system. Typical substances include gas, fat, and blood clots.

Embolus

A substance, such as gas, blood, or fat which travels around the blood stream, until it forms a blockage in a blood vessel.

Emesis

Vomiting.

Emetogenic

Something which causes nausea/vomiting.

Emphysema

Where the alveoli (air sacs) in the lungs lose their elasticity, causing them to narrow. Consequently, the lungs lose their efficiency at getting oxygen into the body, so the sufferer has to breathe harder (characteristic shortness of breath).

Empyema

A mass of pus in the pleural or other cavity.

End Tidal CO₂

Exhaled carbon dioxide, typically 4%-6% (35-45 mm/Hg).

Endometriosis

A condition in which cells from the Endometrium (lining of the uterus) grow outside of the uterine cavity, usually on the peritoneum lining the abdominal cavity. These cells respond to hormones in the same way as those in the lining of the womb but, with no outlet available, the affected tissue becomes inflamed, scarred, and attracts adhesions. The result is severe pain.

Enzyme

A protein which catalyses a biological reaction.

Epicardium

Outer layer of the heart wall.

Epiglottis

Leaf shaped cartilage which sits on top of the larynx, and is attached to the thyroid cartilage. Prevents food from entering the trachea when swallowing.

Epitheliasation

Development of surface layer skin cells.

Epithelium

Layer of cells which line tissues, or the surface of the skin.

Erythrocytes

Mature red blood cells which contain haemoglobin; created in red bone marrow.

Erythromycin

A macrolide antibiotic which slows or stops the growth of bacteria, and is often used in patients with Penicillin allergy.

Extracellular

External to the cells.

Extracorporeal

Where blood is taken from a patient´s circulation, and a process applied to it, before being returned to the circulation.

Extravasation

A discharge or escape of blood/serum/lymph, from a vessel, into the tissues.

Exudation

The discharge of serous fluid through the walls of blood vessels.

Fascia

The connective fibrous tissue which surrounds muscles, blood vessels, and nerves.

Fasciculations

Isolated muscle twitching.

Fibrillation

Quivering and vibration of muscle fibres.

Fibrin (Factor 1A)

An insoluble fibrous protein (formed from Fibrinogen by the action of Thrombin) which forms a mesh over Platelets, helping to form a blood clot over a wound.

Fibrinogen

A soluble protein, produced by the liver, and contained within blood plasma. During the blood clotting process, Fibrinogen is converted into Fibrin by Thrombin.

Fibrinolysin

Enzymes which promote the dissolution of blood clots.

Fibrinolysis

A normal body process which keeps naturally occurring blood clots from growing. Primary fibrinolysis refers to the normal breakdown of clots. Secondary fibrinolysis is the breakdown of blood clots due to a medical disorder, medicine, or other cause, and which may cause severe bleeding.

Blood clots form on fibrin (a protein). The breakdown of fibrin (fibrinolysis) can increase under certain conditions, such as:

Bacterial infections
Cancer
Intense exercise
Low blood sugar
Not enough oxygen to tissues

Fistula

An abnormal passage between 2 organs, usually between cavities, or between a cavity and the body surface.

Forward heart failure

Low blood pressure and poor organ perfusion.

Fraction of inspired oxygen (FiO₂)

The percentage of oxygen in each inspired breath. The FiO₂ is expressed as a number from 0 to 1 (0-100%). The FiO₂ of normal atmospheric air is 21%. Breathing 100% oxygen for extended periods can lead to oxygen toxicity in adults; the figure is 60% or more for infants.

Fracture

A break in a bone.

Fracture type	Description
Simple (closed)	The break does not pierce the skin
Greenstick	A partial fracture, where one side of the bone is broken, the other side is bent; occurs in children
Compound (open)	A broken end of a bone protrudes through the skin
Comminuted	The broken bone is crushed or splintered
Impacted	One end or the fractured bone is forced into the other part of the break

Fremitus

Vibration inside the body, felt from the outside by hand or stethoscope.

Fresh Frozen Plasma

An unconcentrated form of blood plasma, the liquid portion of human blood which has been frozen and preserved after a blood donation. FFP contains all of the clotting factors, except platelets. FFP can be used to supplement red blood cells, when whole blood is not available for exchange transfusion, or to correct a bleeding problem of unknown cause. FFP is also used to correct disseminated intravascular coagulation.
Thawed FFP is best used immediately, but may be stored at 4°C, and infused within 24 hours - if kept at this temperature, or returned to the blood bank for storage within 30 minutes of removal from the fridge.
Dose: 12-15 ml/kg body weight (3-4 units for an adult).
Typical infusion rate is 10-20 ml/kg/hour.

Anaesthesia UK || GOSH || Doses

Fundus

The base of an organ.

Ganglion

A mass of nerve cells and fibres, outside of the central nervous system. Also, describes a cystic welling on a tendon.

Gas exchange

Between the lungs and the blood: Cal State || Youtube

Glottis

The true vocal folds (chords) and the space between them.

Glucagon

Polypeptide produced by the pancreas, which helps to break down glycogen in the liver, raising the blood sugar level.

Goitre

Enlargement of the thyroid gland.

Haematocrit

A measure of the percentage of red cells found in the blood. The normal range is 43-49% in men, and 37-43% in women.

Haematoma

A swelling which contains clotted blood.

Haemoglobin (Hb)

The complex protein molecule contained within red blood cells (erythrocytes), which give them their colour, and by which oxygen is transported. The fraction of haemoglobin which carries oxygen is the measurement for oxygen saturation.
The normal range of haemoglobin is 13.5 to 17.5 g/dl for men, and 11.5 to 15.5 g/dl for women. More

Haemathorax

An accumulation of blood in the pleural cavity.

The Heart

The heart comprises two pumps, left and right. The right side pump sends blood to the lungs, to be oxygenated and to remove waste products, such as CO₂. The left side pump sends blood around the systemic circulation, to oxygenate the cells. More

Heart block

An arrhythmia, caused when impulses from the sinoatrial node are interrupted between the atria and ventricles, resulting in the independent contraction of the atria and ventricles. Block of the Atria Ventricular node (AV block) is the most common type of heart block.

Type of block	Effect on impulses
First degree	Impulses are longer
Second degree	Impulses are missing
Complete	Impulses are absent

Hepatic vein

The vein which takes blood from the liver to the Inferior Vena Cava.

Hernia

Protruding part of an internal organ through it's enclosing structure. Commonly referred to as a rupture.

Type	Description
Hiatus	Part of the stomach protruding through the oesophageal opening in the diaphragm
Incisional	Hernia at an old wound
Inguinal	Protrusion of the intestine through the inguinal canal
Reducible	When the organ can be pushed back into place

Hiatus

A space or opening.

Histology

The study of tissues.

Hives (urticaria, nettle rash)

The recurrent eruption of irritating weals, redness, and itching.

Hormones

A hormone (Greek "impetus") is a chemical released by a gland (Endocrine system) in one part of the body, and travels to a target receptor on a cell in another part of the body, where it stimulates an affect. A hormone acts as a catalyst for cellular level chemical changes, necessary for homeostasis, growth, development, and energy. Endocrine hormone molecules are released into the bloodstream. Exocrine hormones are secreted into ducts, and then flow into the bloodstream, or travel (by diffusion) from cell to cell, in a process known as paracrine signalling.

Hyperaemia

Excess of blood in a body part.

Hyperalgesia

Excessive sensibility to pain.

Hypercalcaemia

Excess of calcium in the blood.

Hypercapnia (hypercarbia)

Increased level of carbon dioxide in arterial blood, causing over stimulation of the respiratory centre, and depression of the central nervous system. The result is confusion, drowsiness, and lack of cooperation from the patient.
Partial pressure of CO₂ (PaCO₂) > 45 mm/Hg (5.9%), typically caused by hypoventilation.

Hyperemesis

Excessive vomiting.

Hyperglycaemia

Excess of blood sugar. Signifies diabetes mellitus.

Symptoms..

Thirst
Sweet smelling breath
Vomiting
Rapid, weak pulse

Hyperkalaemia

Excess of potassium in the blood (greater than 5.5 mmol/l), which can result in cardiac arrest.

Hypernatraemia

Excess of sodium in the blood.

Hyperpneoa

Increased rate and depth of breathing.

Hyperpyrexia

Excessive body temperature - above 41° C.

Hyperthermia

Excessive body temperature - above 38° C. See Temperature

Hyperventilation

Abnormally deep or quick breathing, resulting in faster than normal removal of CO₂ from the lungs, and resultant respiratory alkalosis. Symptoms include:

Dizziness
Tingling in the extremities
Sweating
Wheezing
Shortness of breath

Overview || Basics

Hypervolaemia

Excessive level of blood in the circulation.

Hypocapnia (hypocarbia)

Low level of carbon dioxide (CO₂) in arterial blood. Partial pressure of arterial CO₂ (PaCO₂) < 35 mm/Hg (4.6%), usually caused by hyperventilation.
A normal partial pressure, at rest, is 40 mm/Hg (5.3%). hypocapnia causes cerebral vasoconstriction, leading to cerebral hypoxia. The reduced CO₂ level can suppress breathing.

Hypoglycaemia

A low level of blood sugar. Diabetics may become hypoglycaemic after taking too much insulin, or going too long without food.

Symptoms..

Sweating
Weakness
Hunger
Pale, dry skin
Shallow breathing

Hypokalaemia

A potassium level of less than 3.5 mmol/l, typically due to dehydration.

Hypoventilation

Aka respiratory depression: Inadequate alveolar ventilation, relative to metabolic CO₂ production, resulting in increased alveolar CO₂ partial pressure, with consequent respiratory acidosis.

Hypoxaemia

A lower than normal partial pressure of oxygen (PaO₂) in arterial blood eg, less than 90% saturation.

Hypoxia

Low level of oxygen in the tissues (cellular level). More

Ileum

The lower part of the small intestine, between the jejunum and caecum.

Ileus

Intestinal obstruction.

Iliac arteries

Left and right branches from the Common Illiac artery, which is distal to the Abdominal Aorta. The Internal Iliac artery supplies the Uterus/Prostate, bladder and buttocks. The External Iliac supplies the lower limbs.

Ilium

The top part of the hip bone.

Infarct

The wedge shaped area of necrosis in an organ, caused by a blocked blood vessel, often as a result of an embolus.

Infarction

The formation of an infarct.

Infection

Inguinal

Relating to the groin.

Inotropes

Affecting the force of muscular contracations, especially of the heart. More

Intercostal Muscles

The muscles found between the ribs. The internal intercostal muscles (inside of the ribcage) extend from the front of the ribs, and go around the back, past the bend in the ribs. The external intercostal muscles (outside of the ribcage) wrap around from the back of the rib, almost to the end of the bony part of the rib in the front. The nipple is located in the 4th intercostal space.

International Normalised Ratio (INR)

A relative measurement of a patient's prothrombin time ratio - how long it takes blood to clot.
Details || Testing

Interosseous

Between bones.

Interstitial fluid

Fluids (excluding plasma), such as extracellular, lymph, cerebrospinal, eye, synovial, serous, and secretions of the gastrointestinal tract. A 70 kg adult male has 12 litres of interstitial fluid.

Intracellular

Within a cell.

Ischaemia

Deficient blood supply to an organ.

Jejunum

Part of the small intestine (6 feet) between the Duodenum and the Ileum.

Lactate

A chemical which is formed when sugars are broken down for energy, in the absence of adequate oxygen. Lactate causes the muscle pain athletes experience after engaging in strenuous physical activity for long periods. In people with mitochondrial disorders, too much lactate forms because the ability to burn foods using aerobic respiration is impaired.
Arterial lactate: 0.5-1.6 mmol/L. Venous lactate: 0.5-2.2 mmol/L

Leukocytes

White blood cells.

Liver Function Test

A measurement of enzymes and proteins, in order to determine how well the liver is functionig. A damaged liver will release enzymes into the blood, and the level of proteins produced by the liver begins to drop. Basics

Maxilla

Upper jaw bone.

Medulla

The soft inner part of an organ. The outer part being the cortex.

Mendelson's Syndrome

Aspiration pneumonitis: acid aspiration into the lungs. More

Mesentery

A fold of the peritoneum, connecting the small intestine and abdominal organs to the posterior abdominal wall.

Metabolic Acidosis

A bicarbonate (HCO₃) level less than 22 mEq/L, with a pH less than 7.35; caused by a deficit of base in the bloodstream, or an excess of acids (other than CO₂). More

Metabolic Alkalosis

A bicarbonate level greater than 26 mEq/L, with a pH greater than 7.45; caused by an excess of base, or a lack of acid in the blood. More

Metabolites

Substances produced by metabolic processes.

Metacarpus

The bones between the phalanges (fingers) and carpus (wrist).

Mitral valve (bicuspid)

The one-way heart valve which allows blood to flow from the left atrium to the left ventricle.

Monocyte

White blood cell which ingests bacterial cells.

Muscarinic

Cholinergic postganglionic receptors of the Parasympathetic Nervous System, activated by Acetylcholine.

The binding of Acetylcholine with Muscarinic receptors has several effects:

Binding of Acetylcholine with Muscarinic receptors...

Relaxation of smooth muscle sphincters in GI tract
Contraction of irises
Increased sweating
GI and uterine motility
Salivary and gastric secretions
Bradycardia

Anticholinesterase drugs, such as Neostigmine, increase the above muscarinic effects, so an antimuscarinic agent (Glycopyrrolate, Atropine) must be given to inhibit them.

Myalgia

Muscular pain.

Myasthenia Gravis

An auto-immune disease, which attacks Acetylcholine receptors at the neuromuscular junctions of skeletal muscles. The resultant failure of neuro transmission causes muscle weakness, often affecting muscles which control chewing, speaking, swallowing, and vision.

Myocarditis

Inflammation of the myocardium.

Myocardium

Muscle tissue of the heart.

Nares

The nostrils.

Necrosis

Tissue which has died.

Neoplasia

Process of abnormal growth of new tissue (benign or malignant cells).

Neoplasm

Cells (tumour) produced by neoplasia.

Nerves

A nerve is a bundle of hundreds to thousands of axons, plus associated connective tissue and blood vessels. Each nerve serves a specific region of the body. There are 12 pairs of cranial nerves, and 31 pairs (left and right) of spinal nerves.

Neuromuscular junction

The synapse between the presynaptic motor neuron and the postsynaptic muscle membrane. The axon divides into terminal buttons that invaginate into the muscle fibre.

Neurone

An electrically excitable nerve cell, comprising a cell body, dendrites, and an axon. A neuron responds to a stimulus, by creating an action potential (impulse), which is propogated to it's neighbour.

Neurotransmitter

A substance which is released from axon terminals to bind with receptors at the neuromuscular junction. Examples include:

Acetylcholine
Adrenaline
Dopamine
GABA
Histamine
Noradrenaline
Serotonin
Substance P

Nicotinic

Cholinergic receptors on skeletal muscle end-plate neurons. Activation by Acetylcholine causes depolarisation of cells, with resultant contraction of skeletal muscle.

Oedema

Excessive fluid in tissues. Peripheral oedema results from soft-tissue swelling due to the accumulation of interstitial fluid.

Caused by...

Immobility
Varicose veins
Right heart failure
Pregnancy
Deep vein thrombosis
Allergy
Obesity

Oesophagus (gullet)

The canal running between the pharynx and stomach, approx 10 inches long.

Omentum

Double fold of peritoneum joining the stomach to the abdominal organs.

Oxytocin

A hormone which is normally released by the pituitary gland, towards the end of pregnancy, stimulating the smooth muscle of the uterus (womb). The Oxytocin causes the muscle of the uterus to contract, during labour, so that the baby can be pushed out. Synthetic Oxytocin (Syntocinon) can be used to induce labour.
After the baby has been born, Syntocinon may be given to stimulate contractions which help push out the placenta, and prevent heavy bleeding.

Palpitation

Abnormal rate or rhythm of the heart, felt by the patient.

Parenteral

Apart from the alimentary canal: Introduction of drugs or fluids into the body by a route other than the mouth or rectum, such as IV or subcutaneously.

Parietal

The wall of the body, or of a body cavity, or hollow structure.

Parotid

(1) Near the ear. (2) Salivary gland in front of each ear.

Patella

Kneecap.

Percutaneous

Through the skin.

Perfusion

The passage of fluid through vessels/tissue, such as blood through the lungs.

Pericardium

The fluid filled sac which surrounds the heart and the proximal ends of the aorta, vena cava, and pulmonary artery. Functionally, this sac: fixes the heart in place, prevents overfilling, acts as an infection barrier between the heart and other organs, and reduces friction as the heart moves within the thoracic cavity.

Peritoneum

Serous membrane lining the abdominal cavity, and forming a covering for the abdominal organs.

Parietal peritoneum: membrane lining the abdominal cavity.
Visceral peritoneum: the inner layer which covers the abdominal organs and mesenteries.

Peripheral Nervous System

All of the neurons which are either partly or entirely outside of the central nervous system, and comprising the Sensory-Somatic and Autonomic systems.

Sensory-Somatic system:
Controls glands and the skeletal muscles (to move the bones), by use of motor neurons. Comprises 12 pairs of cranial nerves, and 31 pairs of spinal nerves.

Autonomic system:
Controls the visceral organs.

Percutaneous

Through (per) the skin (cutis).

Pericardium

The fluid filled sac which surrounds the heart and proximal ends of the aorta, vena cava, and pulmonary artery. Functionally, this sac fixes the heart in place, prevents overfilling of the heart, lubricates the heart (prevents friction), and protects the heart from infection.

Petechial rash

A purpuric non-blanching rash, caused by bleeding into the skin layers.
Causes | NICE guidance

Phlebitis

Inflammation of a vein.

Plasma

Clear, yellowish (or straw coloured) extracellular fluid, which is the liquid part of blood. More

Plasma Cholinesterase (pseudocholinesterase)

An enzyme, made by the liver, and present in the bloodstream, which breaks down Suxamethonium. A deficiency results in Suxamethonium apnoea.

Platelets (thrombocytes)

Take part in the clotting process. Platelets are transfused when a patient has a low platelet count (thrombocytopenia), or whose platelets are functioning abnormally. There are 150,000 - 450,000 platelets per microlitre of blood. Each unit of platelets raises the count by approximately 5,000 platelets per microliter of blood.

Pleura

Serous membrane lining the chest cavity, covering each lung.

Plexus

A network of nerves, veins, or lymphatics.

Pons

A bridge of tissue connecting parts of an organ.

Popliteal

The back of the knee.

Portal

Referring to a vein which does not lead to the heart but, instead, has capilliaries at each end, allowing blood to pass between organs.

Postictal state

The abnormal condition occurring between the end of an epileptic seizure and return to baseline condition.

Postpartum

The period shortly after giving birth.

Postural hypotension

Dizziness caused by low blood pressure, which occurs when standing up suddenly.

Potassium

The major intracellular cation, which is involved in maintenance of the resting membrane potential. Hyperkalaemia and hypokalaemia can result in serious cardiac compromise.
Blood serum potassium normal range is 3.5 – 5.3 mmol/L.
Hyperkalaemia: Give 10ml of calcium gluconate 10% intravenously over 2 minutes.

Precipitate

Deposition of solid matter which was previously in solution.

Precordium

The part of the thorax over the heart.

Pregnancy complications

Dehydration, oedema, gastroesophageal reflux disease, DVT, anaemia, abdominal separation.

Pressure Ulcers

Aka Bed Sores: The break down of an area of skin and underlying tissue, caused when the skin is placed under an accumulated pressure. The extra pressure leads to a disruption to the flow of blood through the skin, resulting in reduced perfusion of oxygen and nutrients. The ulcers/sores can range in severity from patches of discoloured skin, to open wounds which expose the underlying bone or muscle. Risk factors

Prolapse

An organ which has moved out of position - downwards.

Proteins

Organic compounds (molecules) which are present in all living cells. Some proteins provide structural support (bone,hair,teeth,cartilage); some proteins, such as enzymes, hormones, antibodies, and globulins, regulate body chemistry; other proteins, such as myoglobin, lipoproteins, and haemoglobin, provide the means of transport of oxygen.

Prothrombotic

Something which leads to thrombosis.

Pruritus

Irritation of the skin.

Pulmonary circulation

Circulation between the heart and lungs.

Pulmonary oedema

Excess fluid in the lungs.

Pulse pressure

The difference between diastolic and systolic pressures.

Pyloric sphincter

The muscle which helps regulate the emptying of food from the stomach into the small bowel.

Pylorus

The opening into the duodenum at the lower end of the stomach, surrounded by the pyloric sphincter.

QRS complex

ECG waveforms which occur at the start of ventricular contraction.

Radial

A bone in the arm, or something which branches.

Rales

Abnormal lung sounds characterized by discontinuous clicking or rattling sounds. They can sound like salt dropped onto a hot pan or like cellophane being crumpled.

Receptor

A special cell or nerve (neuron) ending which detects external stimuli, such as heat or touch, and passes the information to the central nervous system in the form of an impulse.

Reflux

A backward flow; regurgitation.

Respiration

Bitesize

Respiratory Acidosis

A pH less than 7.35, with a PaCO₂ greater than 45 mm/Hg. The acid state occurs when an accumulation of PaCO₂ combines with water to produce carbonic acid, which lowers blood pH. Hypoventilation can lead to Respiratory Acidosis, and an increase in ventilation may correct the problem. More

Respiratory Alkalosis

A pH greater than 7.45, with a PaCO₂ less than 35 mm/Hg, often caused by hyperventilation. More

Respiratory function

The urge to breathe, driven by two factors: firstly, reduced oxygen levels in the tissues; secondly, the level of carbon dioxide in the blood.

Respiratory System

The Lungs, Trachea, Bronchi, and Diaphragm. Supplies the blood with oxygen, through inhalation, which is then delivered to all parts of the body. Exhalations expel waste gases, such as carbon dioxide, which has been delivered to the lungs by the bloodstream.
Description || Physiology || Lecture notes || Youtube lectures || Student resource || More

Saphenous

The nerve which connects the femoral nerve with sensory nerves in the skin of the lower leg.
The 2 veins which drain blood from the foot.

Sagittal

The plane which divides an organ into left and right aspects.

Sartorious

The long muscle which flexes the thigh and lower leg, and extends from the anterior iliac spine, across the thigh, and down to the tibia.

Sepsis

Infection, caused by bacteria, and resulting in pus.

Sequela

A morbid condition resulting from a disease.

Serum

Clear blood plasma, minus corpuscles and fibrin. Serum includes all proteins not used in blood clotting (coagulation) and all of the electrolytes, antibodies, antigens, hormones, and any exogenous substances (e.g., drugs and microorganisms).

Sinoatrial Node

The heart's pacemaker, composed of cardiac muscle fibres, located in the right atrium, and inferior to the opening to the Vena Cava. The SA Node produces an action potential (impulse) at a typical rate of 100 per minute, which leads to the normal sinus rhythm.

Sinus arrhythmia

An abnormal pulse rhythm caused by sinoatrial node disturbance, causing tachycardia on inspiration, and bradycardia on expiration. A slight arrhythmia is normal.

Slough

(sluf): Dead tissue resulting from inflammation or injury, which is washed away by serum exudate.

Somatic

Pertaining to body wall, rather than the viscera.

Soporific

Producing sleep.

Spasm

Sudden involuntrary muscle contraction.

Spicule

A splinter of bone.

Spirometry

The measurement of lung volume and flow rate.

Splanchnic

Referring to viscera.

Stenosis (stricture)

An abnormal narrowing of an opening or vessel, such as an artery.

Stoma

An opening from outside the body to an internal cavity. Examples are Colostomy, Ileostomy, Tracheostomy, and Urostomy.

Stroke

A serious medical condition which occurs when the blood supply to part of the brain is cut off. More

Supraventricular Arrhythmia

An Arrhythmia originating in the Atria.

Syncope

Temporary loss of consciousness.

Synostosis

The fusing of bones by formation of new bone.

Tachypnoea

Fast rate (> 20 breaths/minute) of breathing.

Temperature

A normal body temperature range is 36 - 37.6° C (96.8 - 99.7° F). A high temperature may rise to 40° C (104° F), and is considered a normal response to infection. N.I.C.E. guidelines

Thorax

The chest cavity; containing the heart, lungs, bronchi, and oesophagus.

Thrombin

An enzyme which converts Fibrinogen into Fibrin, during the later stages of blood clotting.

Thromboelastography (TEG)

A test of the efficiency of blood coagulation, platelet function, clot strength, and fibrinolysis. See Monitoring

Thromboplastin

A plasma protein which aids blood coagulation.

Thrombosis

A blood clot within a blood vessel. There are two main types:

Venous thromboembolism
Arterial thrombosis

Thrombus

A stationery blood clot in an unbroken blood vessel, usually a vein.

Tidal volume

V_T is the volume of air displaced between normal inspiration and expiration, when extra effort is not applied. Typical values are 500 ml or 7ml/kg bodyweight.

Tricuspid valve

The one-way heart valve which allows blood to flow from the right atrium to the right ventricle.

Trousseau's sign

Spontaneous peripheral venous thrombosis.

Turgescence

Swelling caused by a build up of fluid.

Ulna

The inner of the 2 bones connecting the elbow and wrist.

Urticaria

Hives, nettle rash: An allergic reaction to an injection or food, causing irritating red patches on the skin.

Uvula

The soft tissue which hangs down the back of the soft palate.

Vagus Nerve (cranial nerve X)

The tenth of twelve paired cranial nerves, and provides parasympathetic nerve supply to the thorax and abdomen. The nerve lies medial and posterior to the internal jugular vein and carotid artery, and extends below the head, to the neck, chest and abdomen, where it contributes to the innervation of the viscera. The vagus nerve also conveys sensory information about the state of the organs to the central nervous system. 80-90% of the nerve fibers in the vagus nerve are afferent (sensory) nerves, which communicate the state of the viscera to the brain.

Varix

An abnormally dilated vessel, typically a vein, with a tortuous course.

Vascularisation

Development of new blood vessels within tissue.

Vasoconstrictor

Aka Vasopressor

Vasopressin

Aka ADH

Venous Thromboembolism

A blood clot which develops in a vein, such as in a vein of the leg (Deep Vein Thrombosis). If part of the clot detaches and travels through the bloodstream to become lodged in another part of the body, it is known as an embolism. If the embolism forms in a lung, it is known as a pulmonary embolism (PE). Venous thromboembolism (VTE) refers to both deep vein thrombosis (DVT) and pulmonary embolism.

Ventilation

The process of exchanging breathing gas, such as air, between the lungs and the atmosphere.

Vesical

Referring to the bladder.

Vesicant

A substance which causes blistering/tissue necrosis.

Virus

An infectious agent which replicates outside of a cell.

Viscera

Plural of viscus.

Viscus

Pertaining to organs within the body cavites, such as the abdomen.

Vomiting

The active reflux action of expelling stomach contents via the oesophagus and mouth. Typical intraoesophageal pressure is 60cm/H₂O

Wounds

A break in tissue, produced by trauma or surgical intervention.

Stages of wound healing...

Cleansing - removal of debris
Granulation - growth of new tissue
Contraction - reduction of wound area
Vascularisation - growth of new blood vessels
Epitheliasation - growth of surface skin