Lifestyle/Human body

Cardiovascular system

Blood and blood vessels

Albumin – a water-soluble protein found in blood plasma

Arteriole – carries blood from arteries to capillaries

Brachial artery – major blood vessel of the upper arm. Used to take blood pressure

Erythrocytes – red blood cells. Have no nucleus

Femoral artery – begins in the lower abdomen and extends through the thigh

Haemoglobin – the iron-containing oxygen-transport protein in the red blood cells of vertebrates. In mammals, the protein makes up about 97% of the red blood cell's dry content, and around 35% of the total content (including water). Haemoglobin transports oxygen from the lung to the rest of the body (i.e. the tissues) where it releases the oxygen for cell use

Hepatic portal vein – drains blood from the gastrointestinal tract and spleen to capillary beds in the liver

Hirudin – a naturally occurring peptide in the salivary glands of medicinal leeches that has a blood anticoagulant property. Hirudin is the most potent natural inhibitor of thrombin

Leukocyte – white blood call

Lumen – the inside space of a tubular structure, such as an artery or intestine

Monocytes – a type of white blood cell. Part of the innate immune system

Phagocyte – a type of white blood cell that can engulf and destroy foreign organisms, cells and particles

Plasma – the clear, yellowish fluid portion of blood, lymph, or intramuscular fluid in which cells are suspended

Platelets – thrombocytes, involved in clotting

Renin – enzyme that regulates blood pressure

Rhesus – blood group system consisting of 50 defined blood-group antigens, among which the five antigens D, C, c, E, and e are the most important ones. The commonly-used terms Rh factor, Rh positive and Rh negative refer to the D antigen only. The blood group O RhD^- is known as the universal donor because it does not carry the A antigen, the B antigen or Rhesus D. The blood group AB RhD⁺ is called the universal recipient. A and B alleles are co-dominant. O allele is recessive

Thrombin – enzyme involved in coagulation

Venule – carries blood from capillaries to veins

The average adult has 10 pints of blood

Heart

Aortic arch – the curved portion of the aorta (the large blood vessel that carries oxygen-rich blood away from the heart to the body)

Blood pressure – varies between a maximum (systolic) and a minimum (diastolic) pressure during each heartbeat. Blood pressure is a measure of the pressure in the brachial artery, the major artery in the upper arm. A person’s blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimetres of mercury (mmHg)

Cardiac cycle – all or any of the events related to the flow of blood that occur from the beginning of one heartbeat to the beginning

Diastole – the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood

Mitral valve (bicuspid valve) – allows the blood to flow from the left atrium into the left ventricle. Stops backward flow of blood in the heart

Pericardium – surrounds the heart

Pulmonary artery – carries blood from the right ventricle of the heart to the lungs. It is the only artery that carries deoxygenated blood

Pulmonary vein – a large blood vessel of the circulatory system that carries blood from the lungs to the left atrium of the heart. In humans there are four pulmonary veins, two from each lung. They carry oxygenated blood, which is unusual since almost all other veins carry deoxygenated blood

Sino-arterial node – acts as the heart’s pacemaker

Systole – the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries

Tricuspid valve – the three flapped valve on the right side of the heart, between the right atrium and the right ventricle which stops the backflow of blood between the two

Vena cava – veins that return deoxygenated blood from the body into the heart. They both empty into the right atrium. The inferior vena cava (or posterior vena cava) travels up alongside the abdominal aorta with blood from the lower part of the body. It is the largest vein in the body. The superior vena cava (or anterior) is above the heart, and forms from a convergence of the veins that contain blood from the head and the arms

Respiratory system

Bronchus – a passage of airway in the respiratory tract that conducts air into the lungs. Bronchi branch into smaller tubes, known as bronchioles

Diaphragm – a sheet of internal skeletal muscle that extends across the bottom of the thoracic cavity. The diaphragm separates the thoracic cavity containing the heart and lungs, from the abdominal cavity

Epiglottis – a flap of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. Srops food and dring entering the lungs

Intercostal muscles – several groups of muscles that run between the 12 pairs of ribs, and help form and move the chest wall

Larynx – short, cartilaginous tube joining the pharynx with the trachea. Also known as the voice box

Lungs – both are separated into lobes by fissures, with three lobes on the right and two on the left. Each lobe is surrounded by a pleural cavity, which consists of two pleurae

Nares – nostrils

Pharynx – the part of the neck and throat situated immediately posterior to the mouth and nasal cavity, and cranial to the oesophagus, larynx, and trachea. It is part of the digestive system and respiratory system of many organisms. Space behind the mouth that serves as a passage for food from the mouth to the oesophagus and for air from the nose and mouth to the larynx

Phrenic – relating to the diaphragm

Pulmonary alveoli – spherical outcroppings of the respiratory sites of gas exchange with the blood. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveoli is taken up by the blood in the alveolar blood vessels, to be transported to all the cells in the body

Spirometer – an instrument for measuring the volume of air entering and leaving the lungs

Tidal volume – the amount of gas passing into and out of the lungs in each respiratory cycle

Trachea – a tube that connects the pharynx and larynx to the lungs. Also known as the windpipe

Vital capacity – the maximum amount of air that can be exhaled after a maximum inhalation

Digestive system

Appendix – a blind-ended tube connected to the cecum

Bile – a digestive juice secreted by the liver and stored in the gallbladder, which aids in the digestion of lipids in the small intestine. It is discharged into the duodenum on eating

Bilirubin – the yellow breakdown product of normal heme catabolism. Heme is found in haemoglobin. Bilirubin is excreted in bile and urine

Cecum – a pouch, usually peritoneal, that is considered to be the beginning of the large intestine. It receives chyme from the ileum, and connects to the ascending colon of the large intestine

Colon – consists of four sections in mammals: the ascending colon, the transverse colon, the descending colon, and the sigmoid colon

Duodenum – the shortest part of the small intestine, where most chemical digestion takes place

Lacteal – a lymphatic capillary that absorbs dietary fats in the villi of the small intestine

Large intestine – colon, cecum (or caecum), and rectum. Absorbs water from food residue and forms and stores faeces

Liver – has a wide range of functions, including detoxification of various metabolites, protein synthesis, and the production of biochemicals necessary for digestion. Liver is divided into four lobes. It is both the largest internal organ and the largest gland in the human body. The liver can regenerate from 25% of its tissue

Meconium – the earliest stool of a mammalian infant

Oesophagus – muscular tube that connects pharynx with stomach. Also known as the gullet

Pancreas – a digestive organ, secreting pancreatic juice containing digestive enzymes that assist digestion and absorption of nutrients in the small intestine

Parietal cells – create gastric acid (hydrochloric acid) in the stomach

Pepsin – an enzyme released in the stomach that degrades food proteins into peptides. It was discovered in 1836 by Theodor Schwann who also coined its name from the Greek word pepsis, meaning digestion

Peristalsis – the process of wave-like muscle contractions of the alimentary canal

Peritoneum – membrane that forms the lining of the abdominal cavity. Reduces friction between organs

Pyloric sphincter – controls the opening between the stomach and the duodenum

Small intestine – duodenum, jejunum and ileum. The major site of digestion and absorption of nutrients

Stomach – located between the oesophagus and the small intestine. It secretes protein-digesting enzymes called proteases and gastric acid to aid in food digestion. It secretes hydrochloric acid

Taurine – a major constituent of bile

Trypsin – digestive enzyme produced in the pancreas

Villi – small, finger-like projections that protrude from the epithelial lining of the intestinal wall

Mouth and throat

Buccal cavity – the mouth

Canines – known as eye teeth, and are also called cuspids

Eye teeth – upper canine teeth

Odontoblast – biological cell that is part of the outer surface of the dental pulp, and whose biological function is the creation of dentin, the substance under the tooth enamel

Papillae – on the tongue contain taste buds

Parotid – paired glands that are the largest of the salivary glands

Philtrum – a vestigial medial depression between the nose and upper lip

Teeth – humans are diphyodont, meaning that they develop two sets of teeth. Humans have 8 incisors, 4 canines, 8 premolars and 12 molars. Dental pulp – the central part of the tooth filled with soft connective tissue. This tissue contains blood vessels and nerves that enter the tooth from a hole at the apex of the root. Streptococcus mutans is commonly found in the human oral cavity and is a significant contributor to tooth decay. A child has 20 deciduous (milk) teeth

Uvula – a fleshy extension at the back of the soft palate which hangs above the throat

Skeletal system

Bones

The majority of bone is made of the bone matrix. It has inorganic and organic parts. The inorganic composition of bone (bone mineral) is formed from carbonated hydroxyapatite. The organic part of matrix is mainly composed of Type I collagen. There are five types of bones in the human body: long, short, flat, irregular and sesamoid. Longest bones – femur, tibia, fibula, humerus, ulna, radius. Human has 206 bones.

Calcaneus – or heel bone is a bone of the tarsus of the foot which constitute the heel

Capitate bone – in the wrist. Largest of the carpel bones

Carpal bones – eight bones in the wrist (carpus)

Cervical vertebrae – almost all mammals have seven cervical vertebrae, (including those with very short necks, such as elephants or whales, and those with very long necks, such as giraffes)

The first cervical vertebra (C1) is named for the Atlas of mythology, because it supports the globe of the head

The second cervical vertebra (C2) of the spine is named the axis. It forms the pivot upon which the first cervical vertebra (the Atlas) rotates

Clavicle – collarbone

Coccyx – final segment of the vertebral column. Also known as the tailbone

Cuboid bone – one of the seven tarsal bones of the foot

Cuneiform – three bones in the human foot

Diaphysis – midsection of a long bone

Epiphysis – rounded end of a long bone

Femur – thigh bone. Longest bone in the body

Fibula – calf bone

Foramen magnum – (Latin: 'great hole') is a large opening in the occipital bone of the cranium. It is one of the several apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull

Glenoid cavity – part of the shoulder

Hallux – big toe

Hamate – bone in the hand with a wedge-shaped form

Haversian canals – found in bone

Hip bone (pelvic bone) – consists of three bones: ilium (largest bone), ischium and pubis

Humerus – bone in upper arm

Hyoid bone – (lingual bone) is a horseshoe shaped bone situated in the neck. It is the only bone in the human skeleton not articulated to any other bone. It is held in place by thyroid ligaments. The hyoid bone provides attachment to the muscles of the floor of the mouth and the tongue above, the larynx below, and the epiglottis and pharynx behind

Joint – the location at which bones connect. Classified anatomically into 11 groups

Lunate bone – in the wrist

Mandible – lower jawbone

Mastoid bone – the protuberance of the temporal bone located directly behind the external ear

Maxilla – major bone of the upper jaw

Metacarpals – bones between the carpus and the fingers

Metatarsals – bones between the tarsus and the toes

Myeloid tissue – red bone marrow; the flexible tissue in the interior of bones

Navicular bone – one of the tarsal bones, found in the foot

Paranasal sinuses – air-filled spaces, communicating with the nasal cavity, within the bones of the skull and face

Parietal bones – in the human skull and form, by their union, the sides and roof of the cranium

Patella – the kneecap. Largest sesamoid bone in the body

Pelvis – either the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region of the trunk), or the skeleton embedded in it (sometimes also called bony pelvis, or pelvic skeleton)

Phalanxes – fingers and toes

Pollex – the thumb

Rachis – spine or vertebral column. In the vertebrate spinal column, each vertebra is an irregular bone with a complex structure composed of bone and some cartilage

Radius – bone of the forearm that extends to the thumb side of the wrist

Sacrum – a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones

Scaphoid bone – in the wrist

Scapula – shoulder blade

Sesamoid bone – a bone embedded within a tendon or a muscle

Skull – 21fused bones plus the mandible

Sphenoid bone – an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone. A type of irregular bone

Spine – is made up of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal

Sternum – breastbone

Synovial fluid – found in the cavities of synovial joints. With its yolk-like consistency, the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement

Talus – ankle bone

Temporal bones – situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum and support that part of the face known as the temple

Tibia – shinbone

Trapezoid bone – in the wrist

Ulna – bone of the forearm that extends to the little-finger side of the wrist and runs parallel to the radius, which it exceeds in length and size

Vomer bone – in the skull

Xiphod process – a small cartilaginous process (extension) of the lower part of the sternum

Zygomatic bone – cheek bone

Nervous system

All-or-none principle – the conduction of nerve impulses is an example of an all-or-none response. In other words, if a neuron responds at all, then it must respond completely

Anabolism – the phase of metabolism in which simple substances are synthesized into the complex materials of living tissue

Autonomic nervous system (ANS or visceral nervous system) is the part of the peripheral nervous system that acts as a control system. It is classically divided into two subsystems: the parasympathetic nervous system and sympathetic nervous system

Axon – the long, hair-like extension of a nerve cell that carries a message to the next nerve cell

Blood-brain barrier (BBB) – a separation of circulating blood and cerebrospinal fluid (CSF) in the central nervous system (CNS)

Central nervous system (CNS) consists of the brain and the spinal cord, as well as the retina

Cranial nerves are nerves that emerge directly from the brain in contrast to spinal nerves which emerge from segments of the spinal cord. The 12 pairs of cranial nerves are traditionally abbreviated by the corresponding Roman numerals

  Olfactory (I)

  Optic (II)

  Vagus (X) is the longest cranial nerve. Supplies branches to many major internal organs

Dendrite – small process branching out from the neuron that detects electrical signals emitted by other neurons and transmits them to the cell body

Dopamine – a neurotransmitter. It plays a major role in the brain system that is responsible for reward-driven learning

Ganglion – a mass of nervous tissue, composed principally of nerve-cell bodies, usually lying outside the central nervous system

Glial cells (glia) – maintain homeostasis, form myelin, and provide support and protection for the brain's neurons

Laryngeal nerve – or Galen's nerve, is a nerve originating from the vagus nerve. Galen demonstrated that cutting the laryngeal nerve rendered an animal voiceless

Meissner corpuscle – nerve ending in the skin

Meninges – membranes that envelop the central nervous system. Dura mater, or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for keeping in the cerebrospinal fluid. The name dura mater is derived from the Latin for ‘hard mother’. Arachnoid mater, literally from Latin ‘spider (web)-like mother’ is the middle meningeal layer. Pia mater is the delicate innermost layer of the meninges. The name pia mater is derived from the Latin for ‘tender mother’

Motor neurons – neurons located in the CNS that project their axons outside the CNS and directly or indirectly control muscles

Myelin – the fatty sheath coating the axons of the nerves; it allows efficient conduction of nerve impulses

Myelin sheath gaps or nodes of Ranvier are the gaps formed between the myelin sheaths generated by different cells. At nodes of Ranvier, the axonal membrane is uninsulated and therefore capable of generating electrical activity

Neuron – nerve cell: a cell that is specialized to conduct nerve impulses

Neuron doctrine – a descriptive term for the fundamental concept that the nervous system is made up of discrete individual cells, a discovery due to decisive neuro-anatomical work of Santiago Ramon y Cajal

Neurotransmitters – endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. There are ten core neurotransmitters, including acetylcholine and adrenaline

Nociceptor – a sensory receptor that responds to potentially damaging stimuli by sending nerve signals to the spinal cord and brain

Peripheral nervous system (PNS) – consists of the nerves and ganglia outside of the brain and the spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs

Receptor – a specialized cell or group of nerve endings that responds to sensory stimuli

Schwann cells – the main glia of the peripheral nervous system. There are two types of Schwann cell, myelinating and nonmyelinating. Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath

Sciatic – longest nerve in the human body. It begins in the lower back and runs through the buttock and down the lower limb

Serotonin – a neurotransmitter involved in e.g. sleep and depression and memory

Solar plexus – known as the celiac plexus, is a complex network of nerves (a plexus) located in the abdomen

Somatic nervous system (SNS) – the part of the peripheral nervous system associated with the voluntary control of body movements through the action of skeletal muscles, and with reception of external stimuli, which helps keep the body in touch with its surroundings

Spinal nerves – 31pairs of nerves which carries motor, sensory, and autonomic signals between the spinal cord and the body

Synapse – a junction that permits a neuron to pass an electrical or chemical signal to another cell

White matter – one of the two components of the central nervous system and consists mostly of glial cells and myelinated axons

Brain

Amygdalae – almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing of memory and emotional reactions

Betz cells – large pyramidal cell neurons located within the fifth layer of the grey matter in the brain

Brain areas –

  Forebrain – cerebral hemispheres, thalamus and hypothalamus

  Midbrain – connects forebrain to hindbrain and spinal cord

  Hindbrain – cerebellum, medulla oblongata and the pons

  Left hemisphere of brain is traditionally associated with logical thinking and language

  Right hemisphere of brain is traditionally associated with spatial awareness and intuition

  Lobes of the brain – frontal, temporal, parietal, and occipital

  Frontal lobe is involved in higher mental functions

  Temporal lobe processes auditory information

  Parietal lobe determines sense of space

  Occipital lobe processes visual information

Brainstem – the central trunk of the mammalian brain, consisting of the medulla oblongata, pons, and midbrain, and continuing downwards to form the spinal cord

Brain waves (in increasing frequency) – delta, theta, alpha, beta, gamma, mu

  Delta waves are usually associated with the deepest stages of sleep

  Alpha waves are also called Berger's wave in memory of the founder of EEG. Alpha   waves predominantly originate from the occipital lobe during wakeful relaxation with closed eyes

  Gamma waves may be implicated in creating the unity of conscious perception

Brain-derived neurotrophic factor – (BDNF) is released by the brain during exercise

Broca’s area – a region of the brain with functions linked to speech production. The production of language has been linked to the Broca’s area since Pierre Paul Broca reported impairments in two patients

Cerebellum – the part of the brain at the back of the skull, which coordinates and regulates muscular activity

Cerebral cortex – a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It is constituted of up to six horizontal layers, each of which has a different composition in terms of neurons and connectivity

Cerebrum – comprises a large portion of the brain, comprising the cerebral cortex (of the two cerebral hemispheres), It lies in front or on top of the brainstem

Circle of Willis – a circle of arteries that supply blood to the brain. It is named after Thomas Willis, an English physician

Corpus callosum – a structure of the mammalian brain in the longitudal fissure that connects the left and right cerebral hemispheres. It is the largest white matter structure in the brain

Grey matter – the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites. Outermost layer of cerebral cortex

Hippocampus – a complex neural structure (shaped like a sea horse) consisting of grey matter. A part of the forebrain, located in the medial temporal lobe. It belongs to the limbic system and plays major roles in short term memory and spatial navigation

Hypothalamus – part of the brain that links the nervous system to the endocrine system via the pituitary gland. Controls body temperature, hunger, thirst, fatigue, and circadian cycles. It synthesizes and secretes certain neurohormones, often called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones

Lateral sulcus – (also called Sylvian fissure or lateral fissure) is one of the most prominent structures of the human brain. It divides the frontal lobe and parietal lobe above from the temporal lobe below

Limbic system – complex set of brain structures concerned with emotion, behaviour, motivation, and long-term memory

Localization – the psychological notion that different functions are located in different areas of the brain

Medulla oblongata – the continuation of the spinal cord within the skull, forming the lowest part of the brainstem

Motor cortex of brain – creates nerve impulses

Neuroimaging – the use of various techniques to either directly or indirectly image the structure, function / pharmacology of the brain

Pineal gland – a small, cone-shaped organ in the brain of most vertebrates that

secretes the hormone melatonin. Pinealocytes in the pineal gland produce melatonin

Pituitary gland – an endocrine gland about the size of a pea. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The pituitary gland secretes hormones regulating homeostasis

Pons – the part of the brainstem that links the medulla oblongata and the thalamus

Sulcus – a deep, narrow furrow or groove, as in an organ or tissue. Any of the narrow fissures separating adjacent convolutions of the brain

Thalamus – function includes relaying sensation, spatial sense and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep and alertness

Ventricular system – a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord. The system comprises four ventricles: right and left lateral ventricles, third ventricle, and fourth ventricle

White matter – the paler tissue of the brain and spinal cord, consisting mainly of nerve fibres with their myelin sheaths

Sensory nervous system

Eye

Accommodation – the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies

Aqueous humour – a thick watery substance filling the space between the lens and the cornea

Canthus – corner of the eye where the upper and lower eyelids meet

Choroid – the vascular layer containing connective tissue, of the eye lying between the retina and the sclera

Ciliary muscle – a ring of striated smooth muscle in the eye's middle layer (vascular layer) that controls accommodation for viewing objects

Cones – only work in the day, responsible for colour vision

Conjunctiva – mucous membrane that covers the front of the eye and lines the inside of the eyelids

Cornea – the transparent layer forming the front of the eye

Fovea – located in the centre of the macula region of the retina. The fovea is responsible for sharp central vision

Iris – a flat, coloured, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the centre

Lens – a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina

Orbicularis oculi – a muscle that closes the eyelids

Retina – inner coat of the eye which is a light-sensitive layer of tissue

Rhodopsin – also known as visual purple, is a pigment of the retina that is responsible for both the formation of the photoreceptor cells and the first events in the perception of light

Rods – used for night vision, monochromatic

Palpebral – (and blepharo) relating to the eyelids

Sclera – outer layer, or ‘white’ of the eye

Vitreous humour – the clear gel that fills the space between the lens and the retina of the eyeball

Yellow spot – small area at centre of retina which is rich in cones

Ear

Auricle – visible part of the ear. Also known as the pinna

Bony labyrinth – the rigid, bony outer wall of the inner ear. It consists of three parts: the vestibule, semicircular canals, and cochlea

Cochlea – the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth

Helix – curving outer rim to the ear

Labyrinth – part of the inner ear

Organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or ‘hair cells’

Ossicles – three bones in middle ear; malleus (hammer), incus (anvil) and stapes (stirrup)

Stirrup – smallest bone in the human body

Oval window – a membrane-covered opening which leads from the middle ear to the vestibule of the inner ear

Perilymph – a fluid, nearly identical to spinal fluid, which fills the cochlea

Round window – is in the inner ear. It allows fluid in the cochlea to move

Semicircular canals – three half-circular, interconnected tubes located inside each ear which detect rotational movements. The three canals are the horizontal semicircular canal (also known as the lateral semicircular canal), superior semicircular canal (also known as the anterior semicircular canal), and the posterior semicircular canal. Each canal is filled with a fluid called endolymph and contains a motion sensor with cilia

Tragus – a small cartilaginous flap in front of the external opening of the ear

Utricle – or utriculus, along with the saccule is one of the two otolith organs located in the vestibule of the inner ear. They are sensitive to gravity and linear acceleration

Endocrine system

Bayliss and Starling discovered secretin in 1902. Starling applied the name ‘hormone’ to the chemical in 1905

Adrenal glands – are chiefly responsible for releasing hormones in conjunction with stress, including cortisol, adrenaline (epinephrine) and noradrenaline

Androgen – male sex hormone

Corpus luteum – involved in production of progesterone

Cortisone – a naturally occurring corticosteroid that can be converted to cortisol. Cortisone suppresses the immune system, thus reducing inflammation

Corticosteroids – a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behaviour

Endorphin – hormone produced in the pituitary gland that has analgesic properties. Responsible for positive moods

Erythropoietin – a hormone produced in the kidneys that controls erythropoiesis, or red blood cell production. Also known as EPO

Estradiol – a sex hormone

Exocrine glands – ductal glands that secrete their products (including hormones and other chemical messengers) into ducts that lead directly into the external environment. They are the counterparts to endocrine glands, which secrete their products (hormones) directly into the bloodstream (ductless glands) or release hormones (paracrines) that affect only target cells nearby the release site

Follicle stimulating hormone (FSH) – produced by the anterior pituitary gland. Causes one egg to begin development. This takes place inside a primary follicle of the ovary

Glucagon – hormone secreted by the pancreas, that raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. Glucagon and insulin are part of a feedback system that keeps blood glucose levels at the right level

Leptin – a hormone made by fat tissue that acts on the brain to regulate food intake and body weight

Luteinizing hormone (LH, also known as lutropin) – produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, it stimulates Leydig cell production of testosterone

Melatonin – is intimately involved in regulating the sleeping and waking cycles, and circadian rhythms

Oestrogen – primary female sex hormone, produced in the ovaries. Oestrogens promote the development of female secondary sexual characteristics, such as breasts, and are also involved in the thickening of the endometrium and other aspects of regulating the menstrual cycle

Oxytocin – the first polypeptide hormone to be sequenced and synthesized biochemically. Oxytocin is best known for roles in female reproduction: 1) it is released in large amounts after distension of the cervix and uterus during labour, and 2) after stimulation of the nipples, facilitating birth and breastfeeding

Pancreas – an endocrine gland producing several important hormones, including insulin and glucagon. The pancreas is also a digestive organ. Islets of Langerhans are the regions of the pancreas that contain its endocrine cells

Parathyroid glands – small endocrine glands in the neck that produce parathyroid hormone. Humans have four parathyroid glands, which are usually located behind the thyroid gland. Parathyroid glands control the amount of calcium in the blood and within the bones

Pineal gland – a small, cone-shaped organ in the brain of most vertebrates that

secretes the hormone melatonin. Pinealocytes in the pineal gland produce melatonin

Pituitary gland – an endocrine gland about the size of a pea. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The pituitary gland secretes hormones regulating homeostasis. Known as the “master gland” and hypophysis

Progesterone – a steroid hormone produced in te ovaries involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species

Prolactin – or luteotropic hormone is a peptide hormone primarily associated with lactation. In breastfeeding, the act of an infant sucking the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis

Secretin – hormone made in the duodenum. Causes the stomach to make pepsin, the liver to make bile, and the pancreas to make a digestive juice

Testosterone – produced in the testes

Thrombopoietin – a hormone produced mainly by the liver and the kidney that regulates the production of platelets by the bone marrow

Thymus gland – produces hormones involved in development of T-cells

Thyroid hormones – principally thyroxine (T₄) and triiodothyronine (T₃) are formed from iodine and tyrosine. Iodine is stored in the thyroid gland

Vasopressin – also known as antidiuretic hormone (ADH) has two primary functions: to retain water in the body, and to constrict blood vessels

Urinary system

Bladder – collects urine excreted by the kidneys before disposal by urination

Bowman’s capsule – a cup-like sac at the beginning of the tubular component of a nephron in the kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac

Kidneys – are essential to the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and regulation of blood pressure. They serve the body as a natural filter of the blood, and remove water-soluble wastes which are diverted to the bladder. In producing urine, the kidneys excrete wastes such as urea and ammonium. They are also responsible for the reabsorption of water, glucose, and amino acids

Loop of Henle – part of a nephron. It controls how dilute or concentrated urine will be

Nephron – the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine

Urea – a carrier of waste nitrogen

Ureters – tubes made of smooth muscle fibres that propel urine from the kidneys to the urinary bladder

Urethra – a tube that connects the urinary bladder to the external orifice for the removal of fluids from the body

Lymph and immune system

Adenoids – (or pharyngeal tonsils) are a mass of lymphoid tissue situated at the very back of the nose, in the roof of the nasopharynx, where the nose blends into the mouth

Adaptive immune system – provides the vertebrate immune system with the ability to recognize and remember specific pathogens (to generate immunity), and to mount stronger attacks each time the pathogen is encountered

Antibody – has a constant region and two variable regions (antigen-binding sites). Antibodies can come in different varieties known as isotypes or classes

Antigen – any substance (as a toxin or enzyme) that stimulates an immune response in the body (especially the production of antibodies). From ‘antibody generator’

Cytokines – any of a number of substances that are secreted by specific cells of the immune system which carry signals locally between cells, and thus have an effect on other cells. They are a category of signaling molecules that are used extensively in cellular communication

Dendritic cells – process antigen material and present it on the cell surface to the T cells of the immune system

Epitope – also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The part of an antibody that recognizes the epitope is called a paratope

Innate immune system – comprises the cells and mechanisms that defend the host from infection by other organisms, in a non-specific manner. This means that the cells of the innate system recognize and respond to pathogens in a generic way, but unlike the adaptive immune system, it does not confer long-lasting or protective immunity to the host. Innate immune systems provide immediate defense against infection

Lymphatic system – part of the immune system, made up of a network of conduits that carry a clear fluid called lymph. It also includes the lymphoid tissue and lymphatic vessels through which the lymph travels in a one-way system in which lymph flows only toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated with the digestive system such as the tonsils. The system also includes all the structures dedicated to the circulation and production of lymphocytes, which includes the spleen, thymus, bone marrow and the lymphoid tissue associated with the digestive system

Lymph node – an oval-shaped organ of the lymphatic system, distributed widely throughout the body including the armpit and stomach and linked by lymphatic vessels. Lymph nodes are major sites of B, T, and other immune cells. Lymph nodes act as filters for foreign particles

Lymphocyte – a type of white blood cell in the vertebrate adaptive immune system. There are two broad categories of lymphocytes, namely the large granular lymphocytes (natural killer (NK) cells) and the small lymphocytes (T cells and B cells). T, in T cell, stands for thymus, since this is the principal organ responsible for the T cell's maturation. T cells originate in the bone marrow. T helper cells are involved in activating and directing other immune cells, and are particularly important in the immune system. B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response, which is governed by T cells). The principal functions of B cells are to make antibodies against antigens. The abbreviation B, in B cell, comes from the bursa of Fabricius in birds, where they mature

Monoclonal antibodies – monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell, in contrast to polyclonal antibodies which are made from several different immune cells. When used as medications, the non-proprietary drug name ends in –mab

Spleen – primary filtering organ for blood. Also produces cells involved in immune responses. Spleen may help in repairing heart damage

Subclavian veins – points at which lymph enters the blood after collecting in the thoracic duct

Thoracic duct – the largest lymphatic vessel in the body

Thymus gland – is largest and most active during the neonatal and pre-adolescent periods. By the early teens, the thymus begins to atrophy. Functions are the production of T-lymphocytes (T cells), which are critical cells of the adaptive immune system, and the production and secretion of thymosins, hormones which control T-lymphocyte activities and various other aspects of the immune system

Muscular system

Abductor muscle – any muscle used to pull a body part away from the midline of the body

Antagonistic muscles – found in pairs called antagonistic pairs. These consist of an extensor muscle, which ‘opens’ the joint (i.e. increasing the angle between the two bones), and a flexor muscle, which does the opposite to an extensor muscle, e.g. biceps and triceps

Biceps – a two-headed muscle that lies on the upper arm between the shoulder and the elbow

Deltoid – the muscle forming the rounded contour of the shoulder

Gluteus maximus – hip muscle. Bulkiest muscle in the body

Masseter muscle – used in chewing

Muscle types – smooth (involuntary), skeletal (a type of striated muscle, voluntary) and cardiac. Human body has c. 640 skeletal muscles

Myology – study of muscles

Myoglobin – an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to haemoglobin

Rotator cuff – the group of muscles and their tendons that act to stabilize the shoulder

Sarcomere – the basic unit of a muscle. Muscles are composed of tubular muscle cells (myocytes or myofibres), which are formed in a process known as myogenesis. Muscle cells are composed of tubular myofibrils

Sarcoplasmic reticulum – a special type of smooth endoplasmic reticulum found in smooth and striated muscle

Sartorius – longest muscle. Runs down the length of the thigh

Soleus – powerful muscle in the calf

Sphincter – a structure, usually a circular muscle, which normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning

Triceps brachii – the large three-headed muscle on the back of the arm

Triceps surae – commonly known as the calf muscle

Connective tissue

Adipose tissue – loose connective tissue composed of adipocytes. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. In mammals, two types of adipose tissue exist: white adipose tissue (WAT) and brown adipose tissue (BAT)

Cartilage – a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones

Collagen – the fibrous protein constituent of bone, cartilage, tendon, and other connective tissue. It is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content

Elastin – a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting

Fascia – connective tissue that connect muscles to other muscles

Hamstring – any of the tendons at the rear hollow of the human knee

Ligament – fibrous tissue that connects bones. Knee has anterior and posterior cruciate ligaments

Plantar fascia – the thick connective tissue (fascia) which supports the arch on the bottom (plantar side) of the foot

Vinculum – a type of ligament that limits the movement of an organ or body part

Tendon (sinew) – a tough band of fibrous connective tissue that connects muscle to bone

Visceral fat – adipose tissue located inside the peritoneal cavity, packed in between internal organs and torso, as opposed to subcutaneous fat which is found underneath the skin, and intramuscular fat which is found interspersed in skeletal muscle

Reproduction and embryology

Blastocyst – a structure formed in the early gestation of vertebrates. It is preceded by the morula. It possesses an inner cell mass, or embryoblast, which subsequently forms the embryo, and an outer layer of cells, or trophoblast, surrounding the inner cell mass and a fluid-filled cavity known as the blastocoele

Colostrum – thin, white, first milk produced by the breasts during late pregnancy and for a few days after childbirth. Also known as beestings

Epididymis – stores sperm, transmitted to penis via vas deferens

Fallopian tube – carries ripe eggs from ovary to uterus

Foetus – an unborn child from the ninth week after fertilization until birth

Fraternal (non-identical) twins – created when two separate eggs are fertilized by two different sperm

Gastrulation – a phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a trilaminar (‘three-layered’) structure known as the gastrula. These three ‘germ layers’ are known as the ectoderm, mesoderm, and endoderm

Germ cell – any biological cell that gives rise to the gametes of an organism that reproduces sexually. Germ cell layers in the very early embryo – ectoderm (outside layer) mesoderm (middle layer), and endoderm (inner layer)

Identical twins – created when a single sperm fertilises an egg that later splits

Lanugo – very fine, soft, and usually unpigmented, downy hair as can be found on the body of a foetus or newborn baby. Lanugo hair will be shed by three to four months after birth. It is replaced by hair covering the same surfaces called vellus hair

Morula – an embryo at an early stage of embryonic development, consisting of cells (called blastomeres) in a solid ball. Formed from a zygote, develops into a blastocyst

Oestrus cycle – follicular phase, luteal phase, fertilization, menstruation

Ontogeny – the origin and development of an individual organism from embryo to adult

Oocyte – an immature ovum, or egg cell

Parity – the number of times a female has given birth to a baby

Placenta – connects the developing foetus to the uterine wall

Prostate – the function of the prostate is to store and secrete a slightly alkaline fluid, milky or white in appearance, that usually constitutes 25-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid

Semi-identical twins – created when a single egg is fertilised by two sperm, turns into a viable embryo, then splits

Seminal vesicle – produces bulk of seminal fluid

Somatic cell – non-reproductive cell

Somatic cell nuclear transfer (SCNT) – a laboratory technique for creating a clonal embryo, using an ovum with a donor nucleus. It can be used in embryonic stem cell research, or, potentially, in regenerative medicine where it is sometimes referred to as ‘therapeutic cloning’

Urethra – conveys sperm from testes (and urine from bladder)

Uterus – commonly known as the womb. Inner mucous membrane is the endometrium

Vellus hair – short, fine, light-colored, and barely noticeable hair that develops on most of a baby's body from childhood

Vernix – the waxy white substance found coating the skin of newborn babies

Wharton’s jelly – a gelatinous substance within the umbilical cord

Skin, hair and nails

Apocrine – sweat glands develop during the early- to mid-puberty ages within the age range of 13 to 15

Areolar glands – or Glands of Montgomery are sebaceous glands in the areola (of the nipple). The portion of the gland on skin's surface is called Montgomery tubercles

Eccrine sweat glands – (sometimes merocrine sweat glands) are coiled tubular glands derived from the outer layer of skin but extending into the inner layer used for body temperature regulation

Dermis – the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain

Epidermis – is composed of the outermost layers of the skin

Glabrous skin – used to describe the hairless skin on the human body, such as the fingers, palmar surfaces of hands, soles of feet, lips, and penises

Hair – a protein filament (notably keratin) that grows from follicles found in the dermis

Nails – (fingernails and toenails) are made of keratin. Nails grow at an average rate of 3 mm a month

Sebaceous glands – small glands in the skin which secrete an oily matter (sebum) in the hair follicles to lubricate the skin and hair of animals

Skin – soft outer covering of vertebrates. Skin is thinnest on the eyelid. Skin makes up 20% of human body weight

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body. Many glands are made up of epithelial cells. Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport and detection of sensation

Simple epithelial tissues are classified by the shape of their cells. The four major classes of simple epithelium are: simple squamous, simple cuboidal, simple columnar, and pseudostratified

Melanocytes – melanin-producing cells located in the bottom layer of the skin's epidermis. melanogenesis occurs after exposure to UV radiation, causing the skin to visibly tan

Mesothelium – a membrane that forms the lining of several body cavities: the pleura (thoracal cavity), peritoneum (abdominal cavity) and pericardium (heart sac)

Mucous membranes – linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion