General Biology - NCLEX-PN

Lymphoid progenitor cells are produced in all of the following tissues: the liver, the bone marrow, spleen, and gut associated lymphoid tissue (mainly found in the liver and intestines). However, note that the vast majority of all blood cells are produced in the red bone marrow of long bones by hematopoietic stem cells.

Mast cells are rich in granules that contain high concentrations of heparin, histamine, and trypsin, among other preformed proteases. These granules also contain serotonin and various eicosanoids. The function of mast cells is primarily to regulate immune (inflammatory) responses to allergens.

While all of the cells listed may have some indirect involvement in the overall response to a parasitic infection, eosinophils are the only immune cells that are specialized to respond to multicellular parasites, especially helminths such as hookworms and pinworms.

Macrophages, the main blood cells responsible for phagocytosis of debris, bacteria, and virally infected cells, are part of the nonspecific immune response. While they are able to recognize self versus non-self proteins, they are not uniquely sensitive to any particular non-self protein type. Rathe, they phagocytose foreign matter as well as cellular debris. Plasma cells, memory cells, and CD8 T cells are all lymphocytes, and as such they are all part of the adaptive or "specific" immune system, meaning that they are uniquely sensitive to particular pathogenic proteins.

While all of the enzymes listed are present in saliva, lysozyme is the only enzyme listed that has antibacterial properties. This enzyme, present not only in saliva but also in tears, sweat, and breast milk, damages bacterial cell walls, making it an important part of the innate immune system. Amylase breaks down carbohydrates, lipase breaks down lipids, and kallikrein breaks down proteins.

The inferior alveolar nerve exits through the mental foramina of the chin. This nerve is a branch of the mandibular nerve and supplies sensory innervation to the lower teeth. The foramen rotundum transmits the maxillary nerve. The supraorbital foramina transmit the supraorbital artery, vein, and nerve. The greater palatine foramen is located in the palatine bone and transmits the greater palatine nerve, artery, and vein.

The falx cerebri, the dura that separates the two hemispheres of the brain, attaches to a bony projection of the ethmoid bone called the crista galli, or "crest of the rooster." This projection is a distinct landmark that arises from the cribiform plate. The ethmoidal labyrinth and orbital plate do not form any attachments to the dura of the brain.

The scapula has multiple fossa that serve as attachment points of various bones and muscles of the shoulder. Among these are the glenoid fossa, where the head of the humerus articulates with the scapula, the subscapular fossa, which is an attachment for the subscapularis muscle, the infraspinous fossa, to which the infraspinatus attaches, and the supraspinous fossa, to which the supraspinatus muscle attaches. There is no suprascapular fossa on the scapula.

The supraspinatus tendon passes under the acromion, a bony hook-like process at the end of the scapular spine. Inflammation of the supraspinatus muscle or tendon can quickly lead to entrapment of this muscle under the acromion, causing pain and reduced mobility. The coracoid process, another projection from the anterior scapula, is an attachment point for several muscles and ligaments, including the pectoralis minor and the short head of the biceps brachii.

The pelvis is formed by the sacrum and coccyx and the three bones that come together to form the innominate: the ilium, ischium, and the pubis. The ileum is a part of the small intestine.

Selenium is essential for conversion of T4 to T3. Deiodinase enzymes, which remove iodine from T4 during conversion into T3, are selenium dependent. Tyrosine and iodine are both required for synthesis of T4, and iron is the cofactor for conversion of phenylalanine into tyrosine.

Calcitonin is produced by the parafollicular (c cells) of the thyroid as a response to elevated blood calcium levels. Calcitonin reduces plasma calcium by inhibiting osteoclast activity and stimulating osteoblasts to deposit more bone. Parathyroid hormone has the opposite effect - it acts to increase calcium levels when serum calcium decreases. While they may ultimately affect serum calcium levels, thyroid hormone and cortisol are not directly involved in calcium homeostasis.

Thyroid-stimulating hormone (TSH) is produced in the anterior pituitary. Somatostatin, dopamine, and gonadotropin releasing hormone are all hypothalamic hormones. Somatostatin is also secreted by the pancreas, and slows down digestive processes. To remember the hormones of the anterior pituitary, use the following mnemonic: FLAT PEG, Follicle-stimulating hormone, Luteinizing hormone, Adrenocorticotropic hormone, Thyroid-stimulating hormone, Prolactin, Endorphins, Growth hormone.

The large, fan-like ridge of bone that can be felt just under the waist is the iliac crest. The anterior superior iliac spine and the anterior inferior iliac spine are smaller protuberances on the ilium that are important landmarks for assessing malpositions of the bones of the sacroiliac joint. The greater sciatic notch is in the posterior ilium and serves as a passage for several muscles and nerves of the pelvic girdle.

Calcitonin is produced by the thyroid gland. The hormone plays an important role in lowering blood calcium levels. It is also synthesized as a drug and used in the treatment of hypercalcemia. The other three hormones are indeed secreted by the islets of Langerhans in the pancreas. Insulin, secreted by the beta cells lowers blood sugar, glucagon, secreted by the alpha cells, increases blood sugar, and somatostatin, secreted by the gamma cells regulates digestive and metabolic processes. Lipase is not a hormone, but an enzyme that facilitates the breakdown of lipids. The pancreas does indeed secrete lipase.

Endocrine glands secrete hormones into the blood. The endocrine glands include the ovaries, testes, hypothalamus, thyroid, pituitary, adrenal glands, pancreas, the pineal gland, and others. Salivary glands are considered exocrine glands. Exocrine glands secrete substances through ducts to the body surface or into body cavities, such as the mouth in the case of salivary glands.

The head of the femur rests in the acetabulum, a bony socket on the lateral pelvis that is formed by all three bones of the innominate (the ischium, ilium, and the pubis). The pubic symphysis is a midline cartilaginous joint between the pubic bones. The obturator foramen is an opening in the innominate through which multiple nerves and vessels pass. The pubic tubercle is a bony projection on the pubis that serves as an attachment point for inguinal ligament.

All of the bones listed form the posterior portion of the foot. The largest bone in the foot is the calcaneus. It forms the heel and articulates with the bones of the ankle.

The bones that form the anterior half of the foot (but not the toes) are the metatarsals. These are mirrored in the metacarpal bones of the hand. The carpal bones form the wrist, and the phalanges form the toes and the fingers.

Long bones are lengthened during childhood and adolescence via a process referred to as endochondral ossification. In this process, chondrocytes of the growth plate hypertrophy and eventual die, leaving cavities that are then colonized by osteoprogenitor cells. These osteoprogenitor cells then differentiate into osteoblasts, which mineralize the newly forming bone. None of the other answers are actual processes in bone formation or physiology.