vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Germ cell
Germ cell tumors are generally located in the gonads but can also appear in the abdomen , pelvis , mediastinum , or brain . Germ cells migrating to the gonads may not reach that intended destination and a tumor can grow wherever they end up , but the exact cause is still unknown . These tumors can be benign or malignant .
Heart
The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava . The electrical signal generated by the sinoatrial node travels through the right atrium in a radial way that is not completely understood . It travels to the left atrium via Bachmann 's bundle , such that the muscles of the left and right atria contract together . The signal then travels to the atrioventricular node . This is found at the bottom of the right atrium in the atrioventricular septum -- the boundary between the right atrium and the left ventricle . The septum is part of the cardiac skeleton , tissue within the heart that the electrical signal can not pass through , which forces the signal to pass through the atrioventricular node only . The signal then travels along the bundle of His to left and right bundle branches through to the ventricles of the heart . In the ventricles the signal is carried by specialized tissue called the Purkinje fibers which then transmit the electric charge to the heart muscle . Conduction
T cell
All T cells originate from haematopoietic stem cells in the bone marrow . Haematopoietic progenitors ( lymphoid progenitor cells ) from haematopoietic stem cells populate the thymus and expand by cell division to generate a large population of immature thymocytes . The earliest thymocytes express neither CD4 nor CD8 , and are therefore classed as double - negative ( CD4 CD8 ) cells . As they progress through their development , they become double - positive thymocytes ( CD4 CD8 ) , and finally mature to single - positive ( CD4 CD8 or CD4 CD8 ) thymocytes that are then released from the thymus to peripheral tissues . There is some evidence of double - positive T - cells in the periphery , though their prevalence and function is uncertain .
Megaloblastic anemia
The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells ( megaloblasts ) in the bone marrow and also by hypersegmented neutrophils ( those exhibiting five or more nuclear lobes ( `` segments '' ) , with up to four lobes being normal ) . These hypersegmented neutrophils can be detected in the peripheral blood ( using a diagnostic smear of a blood sample ) .
Adolescence
During puberty , bones become harder and more brittle . At the conclusion of puberty , the ends of the long bones close during the process called epiphysis . There can be ethnic differences in these skeletal changes . For example , in the United States of America , bone density increases significantly more among black than white adolescents , which might account for decreased likelihood of black women developing osteoporosis and having fewer bone fractures there .
Polycythemia
The overproduction of red blood cells may be due to a primary process in the bone marrow ( a so - called myeloproliferative syndrome ) , or it may be a reaction to chronically low oxygen levels or , rarely , a malignancy . Alternatively , additional red blood cells may have been received through another process -- for example , being over-transfused ( either accidentally or , as blood doping , deliberately ) or being the recipient twin in a pregnancy , undergoing twin - to - twin transfusion syndrome .
Germ cell
The SRY ( Sex - determining Region of the Y chromosome ) directs male development in mammals by inducing the somatic cells of the gonadal ridge to develop into a testis , rather than an ovary . Sry is expressed in a small group of somatic cells of the gonads and influences these cells to become Sertoli cells ( supporting cells in testis ) . Sertoli cells are responsible for sexual development along a male pathway in many ways . One of these ways involves stimulation of the arriving primordial cells to differentiate into sperm . In the absence of the Sry gene , primordial germ cells differentiate into eggs . Removing genital ridges before they start to develop into testes or ovaries results in the development of a female , independent of the carried sex chromosome .
Epiphyseal plate
Osgood - Schlatter disease results from stress on the epiphyseal plate in the tibia , leading to excess bone growth and a painful lump at the knee .
Anemia
Disturbance of proliferation and maturation of erythroblasts Pernicious anemia is a form of megaloblastic anemia due to vitamin B deficiency dependent on impaired absorption of vitamin B. Lack of dietary B causes non-pernicious megaloblastic anemia Anemia of folic acid deficiency , as with vitamin B , causes megaloblastic anemia Anemia of prematurity , by diminished erythropoietin response to declining hematocrit levels , combined with blood loss from laboratory testing , generally occurs in premature infants at two to six weeks of age . Iron deficiency anemia , resulting in deficient heme synthesis Thalassemias , causing deficient globin synthesis Congenital dyserythropoietic anemias , causing ineffective erythropoiesis Anemia of renal failure ( also causing stem cell dysfunction ) Other mechanisms of impaired RBC production Myelophthisic anemia or myelophthisis is a severe type of anemia resulting from the replacement of bone marrow by other materials , such as malignant tumors or granulomas . Myelodysplastic syndrome anemia of chronic inflammation
Axial skeleton
The word `` Axial '' is taken from the word `` axis '' and refers to the fact that the bones are located close to or along the central `` axis '' of the body .
Apoptosis
On the other hand , loss of control of cell death ( resulting in excess apoptosis ) can lead to neurodegenerative diseases , hematologic diseases , and tissue damage . It is to note that neurons that rely on mitochondrial respiration undergo apoptosis in neurodegenerative diseases such as Alzheimer 's and Parkinson 's ( an observation known as the `` Inverse Warburg hypothesis '' ). Moreover , there is an inverse epidemiological comorbidity between neurodegenerative diseases and cancer . The progression of HIV is directly linked to excess , unregulated apoptosis . In a healthy individual , the number of CD4+ lymphocytes is in balance with the cells generated by the bone marrow ; however , in HIV - positive patients , this balance is lost due to an inability of the bone marrow to regenerate CD4+ cells . In the case of HIV , CD4+ lymphocytes die at an accelerated rate through uncontrolled apoptosis , when stimulated . Treatments
Bone age
Pediatric endocrinologists frequently order bone age x-rays to evaluate children for advanced or delayed growth and physical development . These are interpreted by pediatric radiologists , physicians who are experts in using medical imaging for pediatric diagnosis and therapy .
Peripheral chemoreceptors
Peripheral chemoreceptors work in concert with central chemoreceptors , which also monitor blood CO2 but do it in the cerebrospinal fluid surrounding the brain . A high concentration of central chemoreceptors is found in the ventral medulla , the brainstem area that receives input from peripheral chemoreceptors . Taken together , these blood oxygen monitors contribute nerve signals to the vasomotor center of the medulla which can modulate several processes , including breathing , airway resistance , blood pressure , and arousal , with central chemoformation about medullary oxygen levels and peripheral chemoreceptors about arterial oxygen . At an evolutionary level , this stabilization of oxygen levels , which also results in a more constant carbon dioxide concentration and pH , was important to manage oxygen flow in air - vs. - water breathing , sleep , and to maintain an ideal pH for protein structure , since fluctuations in pH can denature a cell 's enzymes .
Anemia
Anemia is typically diagnosed on a complete blood count . Apart from reporting the number of red blood cells and the hemoglobin level , the automatic counters also measure the size of the red blood cells by flow cytometry , which is an important tool in distinguishing between the causes of anemia . Examination of a stained blood smear using a microscope can also be helpful , and it is sometimes a necessity in regions of the world where automated analysis is less accessible .
Red blood cell distribution width
Deficiencies of Vitamin B or folate produce a macrocytic anemia ( large cell anemia ) in which the RDW is elevated in roughly two - thirds of all cases . However , a varied size distribution of red blood cells is a hallmark of iron deficiency anemia , and as such shows an increased RDW in virtually all cases . In the case of both iron and B deficiencies , there will normally be a mix of both large cells and small cells , causing the RDW to be elevated . An elevated RDW ( red blood cells of unequal sizes ) is known as anisocytosis .
Sarcoplasmic reticulum
The sarcoplasmic reticulum ( SR ) is a membrane - bound structure found within muscle cells that is similar to the endoplasmic reticulum in other cells . The main function of the SR is to store calcium ions ( Ca ) . Calcium ion levels are kept relatively constant , with the concentration of calcium ions within a cell being 100,000 times smaller than the concentration of calcium ions outside the cell . This means that small increases in calcium ions within the cell are easily detected and can bring about important cellular changes ( the calcium is said to be a second messenger ; see calcium in biology for more details ) . Calcium is used to make calcium carbonate ( found in chalk ) and calcium phosphate , two compounds that the body uses to make teeth and bones . This means that too much calcium within the cells can lead to hardening ( calcification ) of certain intracellular structures , including the mitochondria , leading to cell death . Therefore , it is vital that calcium ion levels are controlled tightly , and can be released into the cell when necessary and then remove from the cell .
White blood cell
They excrete two chemicals that aid in the body 's defenses : histamine and heparin . Histamine is responsible for widening blood vessels and increasing the flow of blood to injured tissue . It also makes blood vessels more permeable so neutrophils and clotting proteins can get into connective tissue more easily . Heparin is an anticoagulant that inhibits blood clotting and promotes the movement of white blood cells into an area . Basophils can also release chemical signals that attract eosinophils and neutrophils to an infection site .
Thymus
The cortex is mainly made up of thymocytes , supported by a network of finely - branched epithelial reticular cells , which is continuous with a similar network in the medulla . This network forms an adventitia to the blood vessels , which enter the cortex via septa near the junction with the medulla . The cortex is the location of the earliest events in thymocyte development , where T - cell receptor gene rearrangement and positive selection takes place .
Germ cell
In the Xenopus egg , the germ cell determinants are found in the most vegetal blastomeres . These presumptive PGCs are brought to the endoderm of the blastocoel by gastrulation . They are determined as germ cells when gastrulation is completed . Migration from the hindgut along the gut and across the dorsal mesentery then takes place . The germ cells split into two populations and move to the paired gonadal ridges . Migration starts with 3 - 4 cells that undergo three rounds of cell division so that about 30 PGCs arrive at the gonads . On the migratory path of the PGCs , the orientation of underlying cells and their secreted molecules such as fibronectin play an important role .
Thymus
In the two lobes , hematopoietic precursors from the bone - marrow , referred to as thymocytes , mature into T cells . Once mature , T cells emigrate from the thymus and make up the peripheral T cells responsible for directing many parts of the adaptive immune system . Loss of the thymus at an early age through genetic mutation ( as in DiGeorge Syndrome ) results in severe immunodeficiency and subsequent high susceptibility to infection .
Digestive enzyme
Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks , in order to facilitate their absorption by the body . Digestive enzymes are found in the digestive tracts of animals ( including humans ) and in the traps of carnivorous plants , where they aid in the digestion of food , as well as inside cells , especially in their lysosomes , where they function to maintain cellular survival . Digestive enzymes of diverse specificities are found in the saliva secreted by the salivary glands , in the secretions of cells lining
Air pollution in the United States
Air pollution is traditionally associated with pulmonary problems , but it also affects the entire body . Nano - sized pollutants can enter the body by penetrating pulmonary tissue after it is inhaled and enter the blood stream via capillaries . Once inside the circulatory system , the heart will spread the pollutants throughout the body . One of the places these pollutants accumulate and affect is the brain and nervous system . The brain is constantly changing and growing throughout a person 's lifetime by reorganizing its synaptic connections in regards to its changing environment . Therefore , presence and buildup of toxic pollutants in the brain can lead to health problems , diseases , and behavior changes and people living in communities with poor air quality , usually low income , and colored communities , have higher chances of becoming ill than wealthy , white communities . Brain
Endocrine system
Secreted hormone From cells Effect Thrombopoietin liver and kidney cells stimulates megakaryocytes to produce platelets
Heart
The heart pumps blood with a rhythm determined by a group of pacemaking cells in the sinoatrial node . These generate a current that causes contraction of the heart , traveling through the atrioventricular node and along the conduction system of the heart . The heart receives blood low in oxygen from the systemic circulation , which enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle . From here it is pumped into the pulmonary circulation , through the lungs where it receives oxygen and gives off carbon dioxide . Oxygenated blood then returns to the left atrium , passes through the left ventricle and is pumped out through the aorta to the systemic circulation − where the oxygen is used and metabolized to carbon dioxide . The heart beats at a resting rate close to 72 beats per minute . Exercise temporarily increases the rate , but lowers resting heart rate in the long term , and is good for heart health .
X chromosome
The X chromosome is one of the two sex - determining chromosomes ( allosomes ) in many organisms , including mammals ( the other is the Y chromosome ) , and is found in both males and females . It is a part of the XY sex - determination system and X0 sex - determination system . The X chromosome was named for its unique properties by early researchers , which resulted in the naming of its counterpart Y chromosome , for the next letter in the alphabet , after it was discovered later .
Heart
In the left heart , oxygenated blood is returned to the left atrium via the pulmonary veins . It is then pumped into the left ventricle through the mitral valve and into the aorta through the aortic valve for systemic circulation . The aorta is a large artery that branches into many smaller arteries , arterioles , and ultimately capillaries . In the capillaries , oxygen and nutrients from blood are supplied to body cells for metabolism , and exchanged for carbon dioxide and waste products . Capillary blood , now deoxygenated , travels into venules and veins that ultimately collect in the superior and inferior vena cavae , and into the right heart . Cardiac
Thymus
The thymus provides an inductive environment for development of T cells from hematopoietic progenitor cells . In addition , thymic stromal cells allow for the selection of a functional and self - tolerant T cell repertoire . Therefore , one of the most important roles of the thymus is the induction of central tolerance .
White blood cell
Eosinophils compose about 2 - 4 % of the WBC total . This count fluctuates throughout the day , seasonally , and during menstruation . It rises in response to allergies , parasitic infections , collagen diseases , and disease of the spleen and central nervous system . They are rare in the blood , but numerous in the mucous membranes of the respiratory , digestive , and lower urinary tracts .
Chromatin
Chromatin is a complex of macromolecules found in cells , consisting of DNA , protein , and RNA . The primary functions of chromatin are 1 ) to package DNA into a more compact , denser shape , 2 ) to reinforce the DNA macromolecule to allow mitosis , 3 ) to prevent DNA damage , and 4 ) to control gene expression and DNA replication . The primary protein components of chromatin are histones that compact the DNA . Chromatin is only found in eukaryotic cells ( cells with defined nuclei ) . Prokaryotic cells have a different organization of their DNA ( the prokaryotic chromosome equivalent is called genophore and is localized within the nucleoid region ) .
Anemia
Reticulocyte counts , and the `` kinetic '' approach to anemia , have become more common than in the past in the large medical centers of the United States and some other wealthy nations , in part because some automatic counters now have the capacity to include reticulocyte counts . A reticulocyte count is a quantitative measure of the bone marrow 's production of new red blood cells . The reticulocyte production index is a calculation of the ratio between the level of anemia and the extent to which the reticulocyte count has risen in response . If the degree of anemia is significant , even a `` normal '' reticulocyte count actually may reflect an inadequate response . If an automated count is not available , a reticulocyte count can be done manually following special staining of the blood film . In manual examination , activity of the bone marrow can also be gauged qualitatively by subtle changes in the numbers and the morphology of young RBCs by examination under a microscope . Newly formed RBCs are usually slightly larger than older RBCs and show polychromasia . Even where the source of blood loss is obvious , evaluation of erythropoiesis can help assess whether the bone marrow will be able to compensate for the loss , and at what rate . When the cause is not obvious , clinicians use other tests , such as : ESR , ferritin , serum iron , transferrin , RBC folate level , serum vitamin B , hemoglobin electrophoresis , renal function tests ( e.g. serum creatinine ) although the tests will depend on the clinical hypothesis that is being investigated . When the diagnosis remains difficult , a bone marrow examination allows direct examination of the precursors to red cells , although is rarely used as is painful , invasive and is hence reserved for cases where severe pathology needs to be determined or excluded .
Lumbar vertebrae
The lumbar vertebrae are , in human anatomy , the five vertebrae between the rib cage and the pelvis . They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process ( since it is only found in the cervical region ) and by the absence of facets on the sides of the body ( as found only in the thoracic region ) . They are designated L1 to L5 , starting at the top . The lumbar vertebrae help support the weight of the body , and permit movement .
Insulin
Insulin is produced in the pancreas and the Brockmann body ( in some fish ) , and released when any of several stimuli are detected . These stimuli include ingested protein and glucose in the blood produced from digested food . Carbohydrates can be polymers of simple sugars or the simple sugars themselves . If the carbohydrates include glucose , then that glucose will be absorbed into the bloodstream and blood glucose level will begin to rise . In target cells , insulin initiates a signal transduction , which has the effect of increasing glucose uptake and storage . Finally , insulin is degraded , terminating the response . Insulin
Anemia
Treatments for anemia depend on cause and severity . Vitamin supplements given orally ( folic acid or vitamin B ) or intramuscularly ( vitamin B ) will replace specific deficiencies .
Blood plasma
Blood plasma is a yellowish coloured liquid component of blood that normally holds the blood cells in whole blood in suspension ; this makes plasma the extracellular matrix of blood cells . It makes up about 55 % of the body 's total blood volume . It is the intravascular fluid part of extracellular fluid ( all body fluid outside cells ) . It is mostly water ( up to 95 % by volume ) , and contains dissolved proteins ( 6 -- 8 % ) ( i.e. -- serum albumins , globulins , and fibrinogen ) , glucose , clotting factors , electrolytes ( Na , Ca , Mg , HCO , Cl , etc . ) , hormones , carbon dioxide ( plasma being the main medium for excretory product transportation ) and oxygen . Plasma also serves as the protein reserve of the human body . It plays a vital role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection and other blood disorders .
Thymus
In the medulla , the network of reticular cells is coarser than in the cortex , the lymphoid cells are relatively fewer in number , and there are concentric , nest - like bodies called Hassall 's corpuscles . These are concentric , layered whorls of epithelial cells that increase in number throughout life . They are the remains of the epithelial tubes , which grow out from the third pharyngeal pouches of the embryo to form the thymus . In the center of the medullary portion there are very few vessels , and they are of minute size .
Bone age
At birth , only the metaphyses of the `` long bones '' are present . The long bones are those that grow primarily by elongation at an epiphysis at one end of the growing bone . The long bones include the femurs , tibias , and fibulas of the lower limb , the humeri , radii , and ulnas of the upper limb ( arm + forearm ) , and the phalanges of the fingers and toes . The long bones of the leg comprise nearly half of adult height . The other primary skeletal component of height is the spine and skull .
Kidney
The kidneys secrete a variety of hormones , including erythropoietin , and the enzyme renin . Erythropoietin is released in response to hypoxia ( low levels of oxygen at tissue level ) in the renal circulation . It stimulates erythropoiesis ( production of red blood cells ) in the bone marrow . Calcitriol , the activated form of vitamin D , promotes intestinal absorption of calcium and the renal reabsorption of phosphate . Part of the renin -- angiotensin -- aldosterone system , renin is an enzyme involved in the regulation of aldosterone levels .
Cell nucleus
The nucleus provides a site for genetic transcription that is segregated from the location of translation in the cytoplasm , allowing levels of gene regulation that are not available to prokaryotes . The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle .
Huntington's disease
Stem cell therapy is the replacement of damaged neurons by transplantation of stem cells into affected regions of the brain . Experiments have yielded mixed results using this technique in animal models and preliminary human clinical trials . Whatever their future therapeutic potential , stem cells are already a valuable tool for studying Huntington 's disease in the laboratory .