Glossary

A-band Is the dark band in muscle fiber which is the com­plex structural assembly of the protein myosin and associated non-myosin components.

Absolute refractory period The period after the occurrence of an action potential during which the membrane is non-responsive to a given stimulus.

Acclimation It refers to the adaptive changes that take place in response to a single climatic variable (normally pro­duced in a laboratory or climatic chamber).

Acclimatization Acclimatization is a long-term adaptive physiological adjustment which results in an increased tolerance to continuous or repeated exposure to complex climatic stressors (normally produced under field conditions).

Achlorhydria It is a clinical condition in which the stomach is unable to produce hydrochloric acid. It is caused due to a variety of reasons such as pernicious anemia, Helicobacter pylori infection, gastric bypass, hypothy­roidism, radiation exposure of gastric mucosa.

Acidosis An abnormally high level of acid in the body fluid. Acute phase proteins (APPs) They are inflammatory mediators or inhibitors mainly produced from liver. Their concentrations increased (or decreased) at the rate of 25% or more at the time of inflammation. They there­fore act as a suitable biomarker of inflammation.

Adducin It is a calcium/calmodulin binding protein existing as αβ dimer that enables capping of actin for spectrin- actin interactions at the junctional complex.

Adenohypophysis The anterior, predominantly glandular part of the pituitary gland secretes various hormones like gonadotropin, somatotropin, ACTH, TSH, prolactin, etc.

Adipokines The cell signalling proteins released from adi­pose tissues. These are the cytokines.

Adipophilin It is called as lipid droplet proteins involved in the production of cytoplasmic lipid droplets during secre­tary differentiation of mammary alveolar epithelium and plasy a pivotal role in both formation and secretion of milk lipids.

Adjuvants Adjuvants are the substances that enhance the immunogenicity of an antigen after causing sustained release of the antigen, stimulating cytokines and chemokines release, recruitment of immune effector cells, helping in antigen processing and presentation.

After hyperpolarization A slight, transient hyperpolariza­tion that sometimes occurs at the end of an action potential.

Agonistic Fighting or aggressive or defensive social behav­ior among the same species, like a threat, attack, retreat, etc.

Agouti-related protein Agouti-related protein, also called agouti-related peptide, is a neuropeptide produced in the brain by the AgRP/NPY neuron. It is synthesized in neu­ropeptide Y-containing cell bodies located in the ventro­medial part of the arcuate nucleus in the hypothalamus.

Alkali reserve It is the capacity of blood to combine with CO₂ and expressed as the volume of CO₂ (mL/100 mL plasma).

Alkaline tide It is a state of metabolic alkalosis developed after heavy meal due to the diffusion of HCO₃^- into the venous blood. During every hydrogen ion secretion, one bicarbonate ion enters into the blood in exchange for chloride by Cl^-ZHCO₃ ^- exchange (CHE) transporter.

Allometric growth Any organ or body part that grows at a different rate than the general body growth.

Allomone A chemical substance released from one species (animal) can influence another animal or species, like, a pheromone.

Anaphylactic reactions It is a localized or systemic fatal host response occurred in response to allergens and mediated by pharmacologically active substances released from mast cells which cause vasodilation, smooth muscle contraction, mucus production, and sneezing.

Angioedema Area of swelling (oedema) of the lower layer of skin and tissue just under the skin or mucous membranes.

Antimicrobial peptides (AMPs) They are used by many organisms as first line of defense against pathogens.

Apnea The cessation of breathing.

Apoptosis A form of programmed cell death by fragmenta­tion of DNA caused by activation or absence of any stimulus or by a genetically regulated physiological pro­cess. It may be termed cell suicide or programmed cell death.

Apotransferrin It is a beta globulin that binds with two molecules of ferric iron per molecule. It is responsible for carrying iron in circulation.

Aquaporins (AQP) These are the family of 28 kDa mem­brane proteins which help in the transport of water and small solutes across the epithelial cells. AQP are activated by arginine-vasopressin via V2-R receptors and translocated to the cellular membrane for water transport.

Astrocytes Are star shaped neuroglial cells with multiple radiating cytoplasmic processes remaining in the CNS.

Atrial natriuretic peptide (ANP) A peptide hormone released from the cardiac atria that promotes urinary loss of Na⁺ in mammals.

Aunting behavior (primates) It is alloparenting performed by any group member other than the mother.

Azoospermia Presence of no spermatozoa in the semen.

B cells Lymphocytes that matured in the bone marrow (or liver during fetal life) or but in birds, in bursa of Fabricius (birds).

Biological rhythm The body as a whole or its components is in a dynamic state where the physiological process repeats itself with more or less constant time intervals. The phenomenon is defined as a “biological rhythm” which is influenced by a “biological clock.”

Blepharoplast Basal body of flagella.

Blood-testes barrier A specialized barrier that is found between blood capillaries and seminiferous epithelium.

Blood-brain barrier (BBB) Is a special kind of barrier in the CNS which isolates neuronal tissue of CNS from the general circulation.

Broca’s area Is a small area on the left side of the brain (sometimes on the right in left-handed individuals) is important in language processing.

Calsequestrin Is the main Ca²⁺ binding protein in the sar­coplasmic reticulum and serves as the main Ca²⁺ storage and buffering protein.

Capacitation Process of changes of spermatozoa in the female genital tract to get competence for fertilization.

Castration Defunct or sterilize the male animal’s testis (or testes) by surgical (orchidectomy), chemical or mechanical methods. It may be unilateral (one testis) or bilateral (both testes). Related words—Spaying: Loss of ovary function (ies) in female animals; Emasculation: Removal of both testes and the penis.

Cerebrospinal fluid Is a colorless fluid found in the ventricles of the brain, central canal of the spinal cord and in the subarachnoid space surrounding the outer sur­face of the brain and spinal cord.

Ceruloplasmin It is a glycoprotein synthesized in the liver and involved in transport of copper.

Chaperone A group of proteins that aid macromolecules, like proteins and nucleic acids, assemble and fold into a complex structure.

Chemokines These are chemotactic cytokines and attract the leukocytes to the site of infection. Structurally chemokines are subdivided into four families based on the N terminal cysteine residue.

Cholangiocytes These are the epithelial cells that form a three-dimensional network of bile ducts. The hepatic bile is modified at the biliary tract through the secretion and reabsorption by the cholangiocytes.

Christiesomes These are the cell fragments containing endoplasmic reticulum, mitochondria, and lipid droplets identified in goat milk which are involved in triglyceride synthesis.

Chromatin A complex of nucleic acids (DNA) and proteins, primarily histones, in the eukaryotic cell nucleus that stains with basic dyes and condenses to form chromosomes during cell division.

Chyme It is a thick semisolid mass of partially digested food together with the digestive secretions formed in the stom­ach and intestine during digestion.

Circadian rhythm The biological process of an organism that is controlled internally (endogenous) and adjusted with the environment (entrainment) displays physiologi­cally and specific behavior patterns in an oscillation of about 24 h sleep-wake cycle.

Circulating cell-free fetal DNA (ccffDNA) It is fetal DNA that circulates freely in the maternal blood. Analysis of ccffDNA may provide earlier diagnosis of fetal conditions.

Cloning Process of producing individual organisms with either identical or virtually identical DNA, either by natu­ral or artificial means.

Clutch (of bird) Eggs lay continuously or at a stretch in the nest by a bird. Clutch size means the number of eggs laid in a group in the nest by a bird.

Cocaine and amphetamine-related transcript (CART) It is a neuropeptide protein. CART appears to have roles in reward, feeding, and stress, and it has the functional properties of an endogenous psychostimulant.

Colony stimulating factor (CSF) These are responsible for differentiation of leukocytes in the bone marrow. There are four families of CSF, namely granulocyte colony­stimulating factor (G-CSF), macrophage colony­stimulating factor (M-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and multiple­colony-stimulating factor (also called IL 3).

Crop It is a pouch like structure originating as a dilatation of the cervical esophagus with food storage function. The crops are well developed in omnivores and herbivores/ granivorous birds compared to carnivorous birds. The crop is absent in ostriches, gulls, owls, geese, and penguins.

Cryoprotectants A cryoprotectant is a chemical that protects biological tissue from harm caused by freezing.

Cystoscope An instrument equipped with light (endoscope) used to examine and medication into the interior of the urinary bladder, ureter, and urethra.

Damage associated molecular patterns (DAMPs)

DAMPs are endogenous molecules released in response to stress or tissue injury and are potent stimulators for non-infectious inflammation. They are also recognized by PRRs. Fibronectin, fibrinogen, defensins, etc. are the examples of DAMPs.

Delta cells (δ-cells or D cells) These are somatostatin­producing cells of the stomach, intestine, and pancreatic islets. D cells have close connection with gastrin­producing G cells, and somatostatin inhibits gastrin release.

Dendritic cells (DCs) These are the antigen presenting cells reside in the skin and mucosal surfaces. They take the antigen by means of endocytosis, phagocytosis, pinocyto- sis, and macropinocytosis and carry the antigen from peripheral lymph nodes and present it to primary lymph nodes.

Dendritic spines It is a small membranous protrusion from a neuron’s dendrite that typically receives input from a single axon at the synapse.

Dog erythrocyte antigen (DEA) The major determinant of canine blood group is dog erythrocyte antigen (DEA), and there are eight major blood groups in the dog, labeled as DEA 1 to 8. The major antigens are DEA 1.1 and DEA 1.2. Dogs can be positive for either DEA 1.1 or 1.2 or are negative for both.

Eclampsia The condition of acute convulsion with high blood pressure in late pregnancy or during labor, or within 24 h after parturition.

Ectopic Occurs unusually or is present in an abnormal position.

Ectotherms Ectotherms are the animals that entirely depend on the environment for their heat production.

Embryo transfer technology (ETT) Embryo transfer is a process in which embryos are harvested from donor females and transferred into the uterus of recipients, who act as a foster mother for the embryonic development for the rest of the pregnancy.

Emphysema Abnormal permanent enlargement and destruction of the alveoli, which are small air sacs deep in the lungs.

End-diastolic volume (EDV) The volume of blood in the ventricle at the end of diastole when filling is complete.

Endotherms Endotherms are the animals which could gen­erate their own heat through metabolic heat production (birds, mammals).

End-systolic volume (ESV) The volume of blood in the ventricle at the end of systole when emptying is complete.

Enterochromaffin (Enteroendocrine cells) These are small polygonal cells found predominantly in the small intestine and appendix, but also scattered in the colon, rectum, and stomach. In gastric mucosa, these cells are found among the parietal and chief cells.

Ependymal cells Are the lining cells of the ventricles of the brain and the central canal of spinal cord are. These cells are ciliated columnar type and are situated between brain extracellular fluid and cerebrospinal fluid (CSF).

Epitopes Epitopes are the antigenic determinants, a small site of an antigen that can activate immune response by activating T or B cells.

Erythropoietin It is a glycoprotein synthesized primarily from kidney. It stimulates the production of pro-erythroblasts from PHSC and increases the number of erythrocytes in the circulation. Tissue oxygenation is the basic regulator for erythropoietin synthesis.

Estivation Estivation refers to a torpid sleeping state during the summer in harmony to hibernation during winter. The major advantage of estivation is to reduce the metabolic rate and Tc to prolong the period of survival of the animal with its energy reserves and preserves a significant quan­tity of water.

Eustachian tube (auditory tube) It is an auditory tube extending from the middle ear to the anterior portion of throat behind the nose. It links the nasopharynx with middle ear. It helps to maintain the air pressure. The secretions from this area protect the middle air from infections.

Eutherian The species of mammals having placenta in the females.

Eutocia Normal parturition, characterized by uterine contractions followed by progressive cervical dilatation and fetal expulsion.

Extravasation Force out or leakage from the vessel to the surroundings.

Feedback inhibitor of lactation (FIL) It is a glycoprotein that acts as local inhibitory factor for milk secretion. FIL prevents the differentiation of mammary secretary epithe­lial cells, suppresses the synthesis of milk protein and lactose, and induces apoptosis in the mammary gland.

Ferritin It is a globular protein that stores iron inside the cells in a soluble non-toxic form.

Fetal hemoglobin It is composed of two alpha and two gamma chains. It has more oxygen affinity than adult Hb. At birth 41-100% of total Hb is HbF and diminished after 2-3 months and remains very small amount in circu­lation (The conjugated/compound protein with car­bohydrate^) components (as non-protein or prosthetic groups) attached to the polypeptide chain.

Gonadostat hypothesis During the prepubertal stage of development, the gonads release low but constant gonadal steroids that exert negative feedback on the hypothalamic neurons for GnRH release. Puberty occurs when the hypo­thalamus is desensitized to gonadal steroids. The hypoth­esis can explain the sexual quiescent before the onset of puberty.

Gular flutter Rapid fluttering of thin skin of floor of mouth and upper throat of bird to facilitate heat loss.

Gyri and sulci The surfaces of hemisphere are highly con­voluted having numerous elevations and depressions known as gyri and sulci, respectively.

Habituation A gradual quantitative change of response which may lead to a loss of response, as a result of repeated stimulation.

Handmade cloning Handmade cloning is microinjection- free modified method of SCNT in which enucleation of oocyte is done by cutting of oocytes by fine microblade.

Hapten They are low molecular weight (below 10,000 Da) substances which can react with its corresponding anti­body but unable to induce immune response by their own. Their immunogenic property can augmented by carrier molecules (albumin or globulin). Example: pneumococcal capsular polysaccharide, polysaccharide C of Streptococci and cardiolipin antigens, etc.

Haptoglobin It is an acute phase protein that synthesized in liver and involved in transportation of hemoglobin.

Harderian glands These are pigmented lacrimal glands situated at the posterior side of the ocular globes. It is seen in many birds and mammals except carnivores. The secretions of these glands are rich in lipid and porphyrin that lubricate the eyes and eyelids.

Hemopexin It is a plasma protein of globulin class that is involved in transportation of heme.

Homeorhesis The orchestrated or coordinated control in metabolism of body tissues necessary to support a physio­logical state.

Hepcidin it is a cysteine rich peptide synthesized by the hepatocytes and involved in compensatory regulation of iron absorption. It inhibits iron transport by blocking ferroportin in enterocytes, hepatocytes, and macrophages during iron deficiency.

Hermaphrodite An organism having both male and female genitalia.

Heterotherms Heterotherms are animals capable of varying their degree of endothermic heat production.

Hibernation Hibernation refers to a cessation of coordi­nated locomotor activity and a reduction in body temperature, total metabolism, heartbeat, and respiration during winter.

Homeorhesis An orchestrated or controlled change in the homeostasis to support a particular physiological state.

Homeostasis The maintenance and existence of a nearly constant internal environment.

Homeotherms Homeotherms are the animals having the ability to control their body temperature within a narrow range nearly around 37-40 °C even when the external temperature varies (e.g., mammals and birds).

H-Y antigen A cell surface antigen (protein) positioned on the Y chromosome is regarded as the major male sex determiner.

Hyperaemia Increase in the inflow of blood in an area of the body compared to other sites.

Hyperchlorhydria (sour stomach/acid stomach) It is a clinical condition in which the gastric HCl production is more than normal. It usually occurs due to higher gastrin production.

Hyperthermia Hyperthermia can be defined as a rise in body temperature above the hypothalamic set point when heat-dissipating mechanisms are impaired or overwhelmed by external or internal heat.

Hypochlorhydria (HCH) It is characterized by reduced secretion of gastric acid. The predominant causes of HCH are chronic atrophic gastritis, Helicobacter pylori infection, or autoimmune disorders.

Hypothermic spiral The thermoregulatory mechanism is impaired when Tc declines lower than 94 °F (34.4 °C) and animals typically stop to shiver or seek heat.

Imprinting behavior It is a form of learning in which a very young animal fixes its attention on the first object with which it has visual, auditory, or tactile experience and thereafter follows that object.

In vitro embryo production (IVEP) (IVEP) In vitro embryo production (IVEP) refers to the processes of in vitro oocyte maturation (IVM), in vitro fertilization (IVF), and the early days of in vitro embryo culture (IVC). Innate lymphoid cells (ILC) These cells are involved in inflammation. They don’t have antigen specificity due to lack of T cell receptor or any other cell surface markers. Their primary role is to produce cytokines.

Insulin-like factor-3 The protein (an insulin-like trophic hormone) encoded by the INSL3 gene has a role in testic­ular descent in fetal life.

Insulin-like growth factor 1 (IGF-1) Also known as somatomedin C, secreted from the liver by the influence of growth hormone maximum before puberty having insulin-like molecular structure binds with binding protein (IGFBP-3) under the regulation of insulin and regulates the cell growth and differentiation.

Interferons (IFN) They were emerged as antiviral proteins but in later their roles in immunomodulation and cancer immunology have been identified. IFNs are classified into three types, type I (IFN-α and IFN-β), type II (IFN-γ), and type III (IFN-λ1, 2 and 3).

Interleukins They are so named with a thought that it was synthesized by leukocytes but later it was found that interleukins can be produced from a variety of cells. They play pivotal role in hematopoiesis, activation, and differentiation of immune cells.

Intermediary metabolism The sum of all intracellular pro­cesses that transform the nutrients into cellular components. It includes the catabolism (breakdown of macromolecules) and anabolism (synthesis of macromolecules).

Interstitial cells of Cajal (ICC) These are bipolar cells or spindle-shaped cells with elongated processes associated with the electrical activity of GI smooth muscles. ICC resembles Purkinje cells of heart with rhythmic oscillating properties hence called “pacemakers of the guts.”

Kai blood types Two new blood groups, namely Kai 1 and Kai 2 were reported in the dogs mostly found in North America. It was so named as Kai meaning “dogs” in Korean. These antigens were biochemically characterized through ELISA, and it was reported that both of these antigens didn’t co-exist but both could be absent.

Kallmann syndrome A genetic disorder (in humans) caus­ing hypogonadism resulting in delayed puberty and total lack of sense of smell (anosmia) or a reduced sense of smell.

Karyogamy Fusion of cell nuclei during fertilization.

Kisspeptin The protein has a role in commencing the secre­tion of gonadotropin-releasing hormone (GnRH) through G-protein coupled receptor (GPR54), particularly during puberty, and also has a role in tumor suppression and kidney function.

Kupffer cells (Littoral cells) They are specialized phago­cytic cells situated adjacent to the sinusoidal endothelial cells of liver. These are the largest proportion of tissue resident macrophages. The major function of these cells is the phagocytosis of pathogens. They also synthesize inflammatory cytokines like TNF-alpha, oxygen radicals, and proteases.

Lactogenesis The process of initiation of milk secretion from mammary gland.

Lactation curve It is the graphical representation of milk production in respect to time. A typical lactation curve of cow is “bell shaped” which follows a rapid accelerating phase and reached peak and then decline till the end of lactation.

Lactoferrin (LF) It is an iron-binding glycoprotein com­posed of a single polypeptide chain comprising of 689 amino acid residues. It has molecular weight between 76 and 80 kDa. Bovine LF can act as antibacterial, antiviral, immune modulator antioxidant, anticancer, and anti-allergic agent.

Lactogenesis Lactogenesis is the biological process of onset of milk secretion which includes the enzymatic and cyto­logical differentiation of mammary alveolar cells in early pregnancy to full lactation after parturition.

Lactose Intolerance It is occurred due to the deficiency of lactase enzyme which hydrolyzes lactose into glucose and galactose. Lactase activity developed in infants which disappeared after weaning. It leads to lactose malabsorp­tion including diarrhea, bloating and flatulence, abdominal pain, and gaseous accumulation in the intestine.

Lactose synthetase It is the principle enzyme of lactose synthesis in the mammary epithelium. It is a complex of two proteins combines reversibly, in 1:1 stoichiometry.

Lactotroph The pituitary cell that produces prolactin.

Leptin A peptide hormone chiefly produced by fat cells and enterocytes in the small intestine acts upon the arcuate nucleus of the hypothalamus to regulate appetite and energy metabolism by reducing burn stored fat in adipose tissue as reduced estrogen and controls the onset of puberty, acting with kisspeptin. It also involves in regula­tion of the inflammatory response.

Luebering-Rapoport pathway In this pathway, mature RBC produces 2,3-diphosphoglycerate (2,3-DPG) which helps to release oxygen from the hemoglobin to make it available for tissue utilization.

Major histocompatibility complex (MHC) These are the cell surface proteins encoded by a group of genes present in chromosome 6 in human. The main function of MHC is to discriminate between self and non-self.

Mammogenesis It is defined as the growth and development of the mammary gland. It occurs through a series of structural and functional development, differentiation, and involution associated with growth and reproductive stages of animals and regulated by hormones and growth factors.

Margination The movement of leukocytes from central to periphery of the blood vessels during inflammatory conditions.

Marsupials The non-placental mammals, having no true placenta but usually have a pouch on the female’s abdo­men that covers the teats and provides to carry the young, under order Marsupialia (like kangaroos, wombats, bandicoots, opossums).

Mast cells Mast cells were identified by Ehrlich in 1878 and initially named as “Mastzellen” meaning well fed cells due to their highly granular cytoplasm. They are mesen­chymal cells phenotypically similar with the basophils and derived from myeloid stem cells and residing in the skin and mucosal tissues. Mast cells play pivotal role in inflam­mation and allergic reactions (type I hypersensitivity).

Mesoclimate The climate of small areas of the earth’s sur­face which may not be representative of the general cli­mate of the district.

Methemoglobin It is the true oxide of hemoglobin as fer­rous iron is converted to ferric iron during the formation of methemoglobin. The oxidizing agents such as ferricyanide and nitrites react with hemoglobin to form methemoglo­bin. Methemoglobin is unable to carry oxygen. Under normal condition, a small amount of methemoglobin is formed in the circulation but the reducing agents such as glutathione, ascorbic acid decrease its accumulation.

Microarray The laboratory tool used to detect the expres­sion of several fragments of genes at the same time. DNA microarrays are extensively used along with RNA, pro­tein, peptide, and carbohydrate microarrays.

Microfold (M) cells These are the specialized epithelial cells found in the intestinal lymphoid tissue (Peyer’s patches). M cells help in antigen transport across the epithelial cells. M cells engulf luminal pathogens and their antigens by phagocytosis and presented to dendritic cells at lamina propria.

Microglia Are small cells with long thin tortuous processes which look like spines and are phagocytic in function and are motile.

Microtubule The globular proteins, alpha- and beta-tubulin made microscopic hollow cylindrical tube, the largest structures in the cytoskeleton of some eukaryotic cells, stretched throughout the cell to provide the cellular shape and keep its organelles in place also transporting materials within cells as well as involve in cellular movement and cell division (spindle).

Micturition The process of voiding urine.

Migrating motor complex (MMC) It is a cyclic motor pattern of the GI tract exhibited during the interdigestive state. It is appeared as clusters of contractions divided into four phases that propagate over a longer intestinal segment.

Milk somatic cells (SCC) These are body derived cells composed of mammary epithelial cells (70-75%) and leukocytes (25-30%) secreted in milk. In normal healthy quarter, the total somatic cell populations are below 100 ? 10³ cells/mL of milk which may increase up to several folds during intramammary infection. They are the cellular defence factors protecting the mammary gland against pathogens.

Monoclonal antibodies Antibodies that bind to a single epitope are called monoclonal antibodies. Monoclonal antibodies are produced from same clone of B cells. Monoclonal antibodies have high specificity and reproducibility.

Monocular vision or periscopic vision It is a type of vision characterized by seeing with only one eye at a time. Animals with laterally placed eyes view the objects with one eye at a time independently of the other eye. This is due to wider visual angle between optic axis and median line of the eye, e.g., amphibians and reptiles.

Mononuclear Phagocytes System (MPS) MPS consists of circulating monocytes and tissue macrophages. After the maturation of the monocytes, they migrate in the tissue and differentiated into tissue macrophages and causing the destruction of the pathogens.

Monotocous Producing single offspring or young at a birth. Monotreme An egg-laying mammal under the order Monotremata.

Motilin It is a gut hormone released from enteroendocrine cells (Mo cells) in the upper small intestine and increases gastrointestinal motility.

Mucosal-associated lymphoid tissue (MALT) They are situated in the mucous membranes of the gastrointestinal, respiratory, and urogenital systems. They resemble the structure of lymph nodes and populated with plasma cells.

Mullerian duct The primordial structure that gives rise to the female reproductive tract.

Multiple Ovulation Embryo Transfer Technology (MOET) It is a process in which a multiple eggs of animal are fertilized and the embryos are collected by flushing.

Myelodysplasia It is characterized by defective formation of blood cell precursors in the bone marrow. Leukemia and thrombocytopenia are also occurred in addition to anemia in myelodysplasia.

Myoepithelial cells These are modified smooth muscle with long cytoplasmic projections that surround each alveolus and small ducts. Due to their long cytoplasmic projections, they are also termed as basket cells.

Myogram Myogram is the graphical representation of the phenomena of muscular contractions.

Myometrium The middle layer in the uterus that is mainly composed of smooth muscle tissue.

Myosin Contractile proteins form the thick filament and attach with actin during muscle contraction.

Natural killer (NK) cells NK cells are responsible for cell mediated immune response due to their cytotoxic activity. Upon activation, NK cells release perforins and granzymes from their granules and cell lysis occurs. Activated NK cells also secrete TNF-α, IFN-γ, interleukins (IL-5, IL-10, IL-13), and chemokines.

Neuropeptide Y (NPY) A neurotransmitter produced mainly in the neurons of the sympathetic nervous system along with different locations including the hypothalamus and performs various physiological and homeostatic pro­cesses, like increasing food intake and energy storage, reducing blood pressure, anxiety, stress, reducing pain perception, and affects the circadian rhythm and HPA axis by modulating stress.

Neutrophil derived microparticles (NDMPs) These are spherical microvesicles of 50-1000 nm diameter containing mRNA, microRNA, cell adhesion molecules (CD11a and L-selectin), and inflammatory proteins surrounded by lipid bilayer.

Neutrophil extracellular traps (NETs) These are extracel­lular meshes composed of chromatin and neutrophil gran­ular proteins that entrap the pathogens and immobilize them. The process is called NETosis.

Niche Niche is a portion of a tissue that creates a unique microenvironment.

Nictitating membrane (third eyelid) A transparent third eyelid present in the medial canthus. It is present in fish, amphibians, reptiles, birds, and mammals (cats, camels, polar bears, seals, and aardvarks) but rare in primates. It protects the eye, and its glands also produce tears.

Nymphomania Abnormal estrous behavior patterns are the most noticeable sign of cystic ovarian disease.

Oligodendrocytes Are neuroglial cells form the myelin sheath in the nerve fibers in CNS.

Orexin It is a neuropeptide released from hypothalamus and gastric mucosa. It stimulates feed intake and gastric HCl secretion.

Organ of Corti It is the receptor organ of hearing situated within the cochlea. It is composed of three rows of outer hair cells and one row of inner hair cells. It helps in transduction of auditory signals and converts mechanical energy into electrical energy to facilitate hearing.

Osmoconformers Organisms whose internal bodily fluids are isotonic to their surroundings.

Ovum pick up Ovum pick up is a non-invasive procedure for recovering oocytes from antral follicles in live animals Oxidative injury The molecular oxygen can be reduced to form highly reactive oxygen species (ROS) such as hydro­gen peroxide (H₂O₂), hydroxyl radical, superoxide anion, hypochlorous acid (HOCl), and nitric oxide (NO). Low concentrations of these free radicals are required for phagocytosis, signal transductions, and the biosynthesis of prostaglandins but higher concentrations of free radicals can be detrimental for the cells in terms of DNA damage, inactivation of enzymes, oxidation of hormones, lipids peroxidation, and membrane disturbance.

Oxyntomodulin It is peptide hormone released from the L cells of duodenum and stimulates gastric acid secretion.

Palade granule Ribosome is also known as Palade granule. Paneth cells They are situated at the base of the intestinal crypt responsible for the secretion of antimicrobial peptides (AMPs) like alpha defensins, secretory phospho­lipase A2 (sPLA2), lysozyme, cathelicidins, C-type lectin regenerating islet-derived protein IIIγ (RegIIIγ), and angiogenin 4. These AMPs help to protect the epithelial barrier.

Panhypopituitarism The condition of inadequate or absent production of all anterior pituitary.

Passerine birds The birds belonging to the order Passeriformes are called Passerine birds. It is also called perching birds; most of the birds are these types, gener­ally small and living near the ground with feet having four toes arranged to allow for gripping the perch.

Passerine Birds have the arrangement of their toes (three pointing forward and one back) to facilitate perching. They are also termed perching birds or songbirds and belong to the order Passeriformes, half of the almost all bird species.

Pathogen associated molecular patterns (PAMP) These are the distinct structures of the pathogens which can be recognized by the immune cells through their pattern recognition receptors (PRRs). Examples are zymosan, peptidoglycans, surface glycoproteins, etc.

Peptide yy (pyy) It is a short (36-amino acid) peptide released from cells in the ileum and colon in response to feeding.

Peroxiredoxin 2 (Prx2) It is one of the most abundant proteins in erythrocytes reducing H₂O₂ and alkyl hydroperoxides to water and alcohol.

Pheromone The chemical substance secreted into the envi­ronment by the animal, bird, and insect influencing the behavior or physiology of others of its species. Animals have generally used it in reproduction, communication, and feeding practices.

Photoperiod The interval in 24 h (a day) during which an organism is exposed to light or receives illumination, i.e., day length.

Photopigments These are the transmembrane proteins of photoreceptors coupled with G-protein. The function of photopigments is to alter the membrane potential of photoreceptors triggered by the light, e.g., opsins and retinene.

Pinocytosis The ingestion of liquid into a cell by the bud­ding of small vesicles from the cell membrane.

Placentophagia It refers to consumption of the afterbirth by either mothers or—in species with male allomaternal care—males as well. It is almost universal in both carniv­orous and herbivorous mammals.

Plasmodesmata Plasmodesmata are cytoplasmic bridges in the shape of minute pores that connect adjoining plant cells to form a symplast or continuous protoplasm.

Platelet Small subcellular fragments that circulate in blood, where they promote homeostasis.

Pleomorphic Cells or nuclei of the cell having variable shape and size.

Plumage The color and arrangement pattern of feathers in birds.

Pluripotential hematopoietic stem cells (PHSCs) They are the cells from which all the cells of the hematopoietic systems are generated. PHSCs have the capability to undergo mitotic cell divisions, and a portion of these cells remains undifferentiated and maintains a constant pool of PHSC throughput life, whereas other portion of PHSCs are programmed for differentiation to produce specialized.

Poikilotherms Poikilotherms are the animals that do not have a control over their body temperature and vary with the environmental temperature. They are also called as temperature conformers (reptiles, amphibia, fishes, and invertebrates).

Point of inflection A point at which the accelerating and decelerating phase meet, the growth rate starts to decrease.

Polyclonal antibodies Antibodies that are secreted by dif­ferent B cell lineages within the body

Polyclonal antibodies Polyclonal antibodies are the hetero­geneous immunoglobulin mixture against a single antigen and can bind with different epitopes of a single antigen. Polyclonal antibodies are produced from different B cell clones.

Polycythemia Vera It is characterized by the proliferation of erythroid precursors occur autonomously independent of erythropoietin. Splenomegaly, leukocytosis, and thrombocytosis are the common clinical manifestations of polycythemia vera. It is generally occurred in dogs and cats of middle age groups (6—7 years).

Polygynous It refers to the mating system in which females have a single mate during some specified period of time or their entire life and males mate with multiple females.

Polyphagia It is an abnormally strong sensation of hunger or desire to eat often leading to or accompanied by overeating.

Prebiotics Non-digestible food ingredient/supplement that selectively stimulates the growth of some or all of the non-pathogenic favorable organisms (bacteria) in the gut of the host.

Preening Preening is a maintenance behavior, found in birds involved the use of the beak to position feathers, and interlock feather barbules to separate.

Primary/azurophilic granules They are the largest granules of neutrophils and are appeared first during promyelocyte stage and they have affinity for basic dye azure A. They contain myeloperoxidase (MPO), proteases lysozyme, elastase, cathepsins, and acid phosphatase. The main function of primary granular contents is antimicro­bial destruction.

Probiotics Combination of live microorganisms (bacteria and yeast) that enhance/boost the gut health as well as overall performance when consumed.

Proctodeum The caudal most portion of the cloaca where cloacal bursa opens. The proctodeum opens outside through vent.

Progenitor cells A progenitor cell is a unipotent cell that can be differentiated into its target cells (e.g., erythroid progenitors can give rise to erythrocytes). Unlike stem cells they have limited self-renewal capacity.

Protamines The major nuclear proteins of spermatozoa, having low molecular weight arginine along with lysine amino acids which replace later histones in the haploid phase of spermatogenesis, essential for sperm head con­densation, maintaining and stabilization of DNA, are protamines. Mutations in the protamine genes cause infer­tility and are considered a biomarker of sperm quality.

Proteomics The identification and study of the proteins of a cell, tissue, or organism to determine their structure, inter­active networks, and function.

Ptyalism Hypersecretion of salivary glands is called ptya- lism. It is characterized by drooling of saliva. Ptyalism is secondary to swallowing disorders in animals. The causes of ptyalism are toxins, drugs, and poison, such as organo­phosphorus compounds, glossitis, stomatitis, convulsive disorders, nervousness, motion sickness, linear foreign body ingestion, and oral tumor.

Pyknosis Degenerative changes and shrinking of the nucleus due to clumping of the chromosomes, associated with hyperchromatic.

Reactive oxygen species (ROS) Oxygen-containing unsta­ble molecule or free radical, which readily react with other molecules, and affect proteins, DNA, RNA even cell death in excess, like, singlet oxygen, superoxide, peroxides, hydroxyl radical and alpha-oxygen.

Reactive oxygen species Used to denote reactive molecules derived from oxygen.

Recombinant gene transfer technology Transfer of desir­able gene sequences from other than sources via appropri­ate vector to obtain improved and desired characteristics in living organism.

Renin A hormone released from mammalian kidneys in response to a decrease in NaCl/ECF volume/arterial blood pressure; activates angiotensinogen.

Restitution It is the process of migration of new cells from the gastric pits to replace the damaged cells within a very short period of time.

Reticular formation: Is the phylogenetically primitive net­work of small neurons occupying the midventral portion of the medulla and midbrain, extending throughout the brainstem and into the spinal cord.

Rheopectic When shear is applied to some colloids, they solidify more quickly.

Rhodopsin It is a biological pigment and G-protein coupled receptor found in the rod cells. Enzyme rhodopsin kinase joins 11-cis retinal and scotopsin to reform rhodopsin.

Rooster An adult male domestic fowl. A hen with a right functional ovary may also be called a rooster.

Rubriblast See proerythroblast.

Satellite cells Are neuroglial cells in the nervous system help in regulation of the external chemical environment around the neurones of the PNS.

Secondary/specific granules These granules are unique to neutrophils hence called specific granules. They are appeared during metamyelocyte stage. The secondary granules contain matrix metalloproteinases (MMPs) (MMP 3, 8, 9), gelatinase, collagenase, lactoferrin, alka­line phosphatase, histaminase, plasminogen activator, and β2 microglobulin. The secondary granules help in micro­bial destruction and neutrophil migration.

Serine proteases A class of proteolytic enzymes that pos­sess serine at the active site.

Silent heat It is defined as the maintenance of ovarian functions without the presence of vulvar edema, serosanguinous vaginal discharge, and charm for male dogs.

Somatic cell nuclear transfer (SCNT) Somatic cell nuclear transfer or cloning is a technique in which the nucleus of a somatic cell is transferred to the cytoplasm of an enucleated egg (an egg that has had its own nucleus removed).

Spermatheca The small cavity or sac in the lower group of female animals to hold the spermatozoa before fertilization.

Spermatogonial stem cells Spermatogonial stem cells (SSCs) are the most primitive spermatogonia in the testic­ular tissue. SSCs maintain highly productive spermato­genesis by self-renewal and ongoing creation of daughter spermatogonia that develop into spermatozoa.

Spermiogenesis The development of mature and motile spermatozoa from spermatid as occurred in the last stage of spermatogenesis.

Stem cell An unspecialized or undifferentiated cell that can generate one or more specialized or differentiated cells like blood cells. It is used in therapeutic due to its regenerating and repairing properties of the damaged tissue.

Stereo vision In this type of vision, 3D images are created from multiple 2D views. Primates, cat, and other felines have three-dimensional view because of small angle between optic axis and median line of the eye with each eye viewing the same object at a different angle.

Streak canal (Ductus papillaris) The distal opening of the teat cistern is called streak canal or teat canal through which milk is removed.

Superantigens These antigens are able to activate a large proportion of T cells (up to 25%) in comparison to con­ventional antigens that are able to induce only 1-2% T cells. The super antigens cause hyper activation of immune system. Pyrogenic exotoxins (leads to shock) and enterotoxins (leads to food poisoning) of

Staphylococci are the examples of super antigens.

Superovulation Superovulation, also known as

superstimulation, is a treatment that aims to boost the donor animal’s ovulation rate and thus the number of available oocytes without interfering with the physiologi­cal and endocrinological processes involved in oocyte maturation, ovulation, and fertilization, as well as embry­onic and fetal development.

Superoxide dismutase (SOD) It is a copper and zinc containing metalloenzyme that catalyzes the transfer of an electron from one superoxide anion (donor) to another (recipient) thus the donor molecule becomes dioxygenated and the recipient rapidly reacts with two hydrogen ions to form hydrogen peroxide. It protects the cell from oxida­tive injury.

Symplast Plasmodesmata between adjacent plasma cells form continuous protoplasm known as symplast.

Syncytium A cytoplasmic mass or a single cell containing multiple nuclei formed either by fusion of cells or by division of nucleus.

Syntaxin Is a family of membrane integrated Q-SNARE proteins participating in exocytosis.

Tapetum lucidum It is a biologic reflector system situated behind the retina in many vertebrate species. It allows the retina to make optimal use of available light by photon­photoreceptor stimulation. It helps in night vision in some nocturnal animals.

Telodendria Are the short branches known as at the termi­nation the axons as well as the axon collaterals.

Telomeres They are non-coding specialized repetitive DNA sequences located at the ends of chromosomes.

Temperate climate The climate of the “middle” latitudes; the variable, climate between the extremes of tropical climate and polar climate.

Thrombocytopathies It is the impairment of platelet functions. It is either congenital (Von Willebrand disease, Glanzmann thrombasthenia, Canine thrombopathia) or acquired (multiple myeloma, chronic kidney diseases, and drug induced).

Thrombocytopenia It is the pathological condition which leads to decrease platelet counts. It is either congenital or acquired (drug induced, Rickettsial diseases, or immune mediated).

Tonoplast Selectively permeable membrane surrounding the sap vacuoles is known as tonoplast.

Totipotent Ability of cell(s) to differentiate into the specialized cell(s), which may be a new individual, organ, or tissue.

Transcriptomics Study of the transcriptome—the complete set of RNA transcripts that are produced by the genome, under specific circumstances.

Transferrin It is a plasma glycoprotein synthesized from liver that binds reversibly with iron in ferric form. Ery­throid precursor cells contain transferrin receptor, and the transferrin bound iron is internalized inside these cells through receptor mediated endocytosis.

Transforming Growth Factor β (TGF-β) It is produced from a variety of cells including T cells and monocytes. The main function of TGF-β is the inhibition of cellular growth and production of extracellular matrix. TGF-β also acts as negative regulator of T cell and macrophage activation.

Transgenesis The process of introducing an exogenous or modified gene (transgene) into a recipient organism of the same or different species from which the gene is derived. Translocation Changing the location of any substance. Transporter protein The protein remaining undyingly across the biological membrane transports ions, small molecules, or macromolecules with a channel or through a carrying mechanism by facilitated diffusion or active transport process from one side to the other.

Treppe Stepwise increase in contraction tension.

Urine marking It is a natural, instinctive behavior in dogs, but it is not appropriate inside the house. Dogs, especially sexually intact male dogs, urinate on objects to leave a message for other dogs (e.g., claiming their territory). Urine marking behavior usually begins when the dog reaches sexual maturity.

Urodeum It is the cloacal compartment lies between coprodeum and proctodeum that stores urine. The ductus deferens opens into the urodeum.

Vasoactive intestinal peptide (VIP) It is neurohormone secreted from postganglionic non-cholinergic neurons of the enteric nervous system. The major functions of VIP are relaxation of GI smooth muscles, stimulation of pan­creatic and biliary secretions, and inhibition of gastric acid secretion.

Ventilation-perfusion ratio (VA/Q.) It is the quantitative measurement or ratio of all the air entering the alveoli to the total blood flowing to both the lungs per minute.

Viviparous The animals that can produce living offspring that develops inside the mother’s body. It happens in mammals and some reptiles and fishes. The animals able to produce eggs are called oviparous.

Von Willebrand disease It is the deficiency of von Willebrand’s factor. It is one of the most common inherited bleeding disorders in canines with almost all the breeds.

Xenotransfusion A form of xenotransplantation was initially defined as the transfer of blood from one species into the veins of another.

Xerostomia (dry mouth) Xerostomia or dry mouth is a clinical condition developing due to hyposalivation. Xerostomia causes discomfort during eating and oral infections. It is uncommon in dogs and cats but can be occurred in animals under frequent radiation exposure. Administration of drugs like atropine, severe dehydration, fever, and anesthesia may also cause hyposalivation. Immune mediated keratoconjunctivitis sicca in canines can also lead to xerostomia.

Yolk Part of the egg nourishes the embryo during its formation.

Z-line Neighboring, parallel lines that define a sarcomere.

Zygote Fertilized egg cell that results from the union of a female gamete (egg or ovum) with a male gamete (sperm). Zymogen An inactive substance that can be converted into an enzyme when activated by another enzyme.

α2-Macroglobulin They are globulin fractions of plasma protein synthesized mainly in liver but also locally by macrophages, fibroblasts, and adrenocortical cells. They are the proteases inhibitor and involved in inflammation. α-Granules They are the largest and most abundant granules of the platelets (50-80/platelet). «-granules are filled with proteins like β-thromboglobulin and thrombospondin to support platelet adhesion and aggrega­tion. Besides these, the «-granules contain some mito­genic proteins such as transforming growth factor-β (TGF-β) and platelet-derived growth factors (PDGF).