Knowledge Navigator Exam I - Cell Biology

**[Knowledge Navigator Exam I]** **Cell Biology** - **Cellular Functions**: Eukaryotic cells have specialized functions including movement, conductivity, metabolic absorption, secretion, excretion, respiration, reproduction, and communication. - **Cellular Structures:** Eukaryotic cel...

**[Knowledge Navigator Exam I]** **Cell Biology** - **Cellular Functions**: Eukaryotic cells have specialized functions including movement, conductivity, metabolic absorption, secretion, excretion, respiration, reproduction, and communication. - **Cellular Structures:** Eukaryotic cells consist of a plasma membrane, cytoplasm, and intracellular organelles. The nucleus contains DNA and controls genetic information. The cytoplasm includes the cytosol, which is a gel-like substance where metabolic processes occur. Organelles within the cytoplasm have specific functions. - **Organelles:** - **Ribosomes** synthesize proteins. - **The endoplasmic reticulum (ER)** is involved in protein synthesis and senses cellular stress. - **The Golgi complex** processes and secretes proteins. - **Lysosomes** are responsible for intracellular digestion and autophagy. - **Peroxisomes** detoxify compounds and fatty acids. - **Mitochondria** produce energy through cellular respiration. - **Vaults** transport messenger RNA (mRNA). - **The cytoskeleton** maintains cell shape and allows for movement of substances. - **Plasma Membrane:** This membrane controls what enters and exits the cell and is composed of a bilayer of lipids and proteins. It facilitates cell-to-cell recognition and provides cellular mobility. - **Cell Adhesion:** Cells adhere to each other through the extracellular matrix and cell adhesion molecules (CAMs) like integrins, cadherins, selectins, and the immunoglobulin superfamily. Specialized cell junctions, such as desmosomes, tight junctions, and gap junctions, hold cells together and allow for communication. - **Cellular Communication:** Cells use various signaling methods including contact-dependent, paracrine, autocrine, hormonal, neurohormonal, and neurotransmitter signaling. Signal transduction involves a series of steps where a signal is transmitted from the cell surface to the interior. - **Cellular Metabolism:** Metabolism involves chemical tasks to maintain cell functions, providing the cell with energy. It includes both anabolism (synthesis, energy-using) and catabolism (breakdown, energy-releasing). ATP is the primary energy carrier in cells. - **Membrane Transport:** - **Passive transport** does not require energy and includes diffusion, facilitated diffusion, filtration, and osmosis. - **Active transport** requires energy to move molecules across the concentration gradient, and an example is the sodium-potassium pump. Vesicle formation is another form of active transport, including endocytosis (taking in) and exocytosis (expelling). - **Cellular Reproduction:** The cell cycle includes interphase (G1, S, G2 phases) and mitosis (prophase, metaphase, anaphase, telophase). Mitosis results in two identical daughter cells. **Altered Cell Biology** - **Cellular Adaptation:** Cells adapt to protect themselves from injury. - **Atrophy** is a decrease in cell size. - **Hypertrophy** is an increase in cell size. - **Hyperplasia** is an increase in cell number. - **Metaplasia** is the reversible replacement of one cell type by another. - **Dysplasia** is deranged cellular growth and is considered an atypical hyperplasia. - **Cellular Injury:** Cell injury can be reversible or irreversible and can lead to cell death. It\'s caused by various factors including hypoxia, free radicals, toxic chemicals, infectious agents, physical and mechanical factors, immunologic reactions, genetic factors, nutritional imbalances and physical trauma. - **Cellular Injury Mechanisms:** These include decreased ATP production, failure of active transport (Na+/K+ pump), cellular swelling, detachment of ribosomes, cessation of protein synthesis, mitochondrial swelling, vacuolation, leakage of digestive enzymes from lysosomes, and lysis of the plasma membrane. - **Ischemia-Reperfusion Injury:** This injury is due to oxidative stress, radicals causing membrane damage, and mitochondrial calcium overload. It can occur in tissue transplantation and ischemic syndromes. - **Carbon Monoxide (CO) Injury:** CO reduces the oxygen-carrying capacity of the blood leading to hypoxic injury. - **Asphyxial Injuries:** These injuries are caused by failure of cells to receive or use oxygen, such as suffocation, strangulation, chemical asphyxiants and drowning. - **Infectious Injuries:** Pathogens can cause injury through invasion, destruction, toxin production, or hypersensitivity reactions. - **Immunologic and Inflammatory Injuries:** These involve phagocytic cells and inflammatory substances like histamine and antibodies causing membrane alterations. - **Temperature Extremes:** Hypothermia slows cellular metabolic processes and produces reactive oxygen species. Hyperthermia leads to heat cramps, exhaustion, stroke, malignant hyperthermia, and burns. - **Ionizing Radiation:** This can cause damage by removing orbital electrons, leading to deterministic and stochastic effects. Bystander effects (horizontal transmission) and genomic instability (vertical transmission) can also occur. - **Cellular Death:** - **Necrosis** includes inflammatory changes and autolysis. - **Apoptosis** is programmed cell death without inflammation and can be normal or pathological. Dysregulated apoptosis can lead to diseases like cancer. - **Autophagy** is a self-destructive process that serves as a survival mechanism. - **Aging:** Aging involves the accumulation of damaged macromolecules and is characterized by progressive stiffness and rigidity. Frailty is a complex syndrome involving oxidative stress and dysregulation of inflammatory cytokines. - **Somatic Death:** This is death of the entire person, without an inflammatory response, and involves cessation of respiration and circulation. Postmortem changes include algor mortis and livor mortis. **Fluid and Electrolytes** - **Body Fluids:** Total body water is divided into intracellular fluid (ICF) and extracellular fluid (ECF), which includes interstitial and intravascular fluid. - **Edema:** This is an alteration in water movement that can be caused by decreased plasma oncotic pressure (e.g. decreased albumin production), increased capillary permeability (inflammation), lymph obstruction and sodium retention. Clinical manifestations include localized or generalized swelling, dependent edema, pitting edema, and weight gain. - **Electrolytes:** Electrolytes are in both ECF and ICF compartments at different concentrations. Cations include potassium (K+) in the ICF and sodium (Na+) in the ECF. Anions include phosphate, organic ions, and proteins in the ICF, and chloride (Cl-) and bicarbonate (HCO3-) in the ECF. - **Sodium and Chloride Balance:** Sodium (Na+) is the primary ECF cation, regulating osmotic forces, neuromuscular excitability and acid-base balance. Chloride (Cl-) is the primary ECF anion, maintaining electroneutrality and following sodium. The renin-angiotensin-aldosterone system (RAAS), aldosterone, and natriuretic peptides regulate sodium balance. - **Water Balance:** This is regulated by thirst perception and antidiuretic hormone (ADH). - **Isotonic Alterations:** These involve total body water changes with proportional electrolyte changes, including isotonic volume depletion (hypovolemia) and excess (hypervolemia). - **Hypertonic Alterations:** - **Hypernatremia:** Serum sodium \> 147 mEq/L, related to sodium gain or water loss, causing intracellular dehydration. Manifestations include convulsions, pulmonary edema, hypotension, and tachycardia. - **Hyperchloremia:** Often occurs with hypernatremia or bicarbonate deficits. - **Water Deficit:** Dehydration leading to tachycardia, weak pulse, postural hypotension, elevated hematocrit and serum sodium, and dry skin. - **Hypotonic Alterations:** - **Hyponatremia:** Serum sodium \< 135 mEq/L, causing plasma hypo-osmolality and cellular swelling. - **Water Excess:** Can result from compulsive water drinking or decreased urine formation such as the syndrome of inappropriate ADH (SIADH). Manifestations include cerebral edema and muscle twitching. - **Potassium (K+):** The major intracellular cation, essential for nerve impulse transmission, cardiac rhythm, and muscle contraction. Regulated by aldosterone, insulin, and pH balance. - **Hypokalemia:** Potassium level \< 3.5 mEq/L, causing membrane hyperpolarization, muscle weakness, and cardiac dysrhythmias. - **Hyperkalemia:** Potassium level \> 5.5 mEq/L, causing muscle weakness, and cardiac arrest. - **Calcium (Ca++):** Most calcium is located in the bone. Necessary for bone structure, blood clotting, hormone secretion, cell receptor function, and muscle contraction. - **Phosphate:** Most phosphate is in the bone and is necessary for high-energy bonds like ATP. Calcium and phosphate concentrations are rigidly controlled; if one increases the other decreases. Regulated by parathyroid hormone (PTH), vitamin D, and calcitonin. - **Hypocalcemia:** Calcium level \< 8.5 mg/dL, causing increased neuromuscular excitability, muscle spasms, and convulsions. - **Hypercalcemia:** Calcium level \> 12 mg/dL, causing decreased neuromuscular excitability, muscle weakness and kidney stones. - **Hypophosphatemia:** Can result in diminished release of oxygen, soft bones, and muscle weakness. - **Hyperphosphatemia:** Related to low calcium, can cause soft tissue calcification. - **Magnesium:** Intracellular cation that interacts with calcium, and is needed for intracellular reactions and neuromuscular excitability. - **Hypomagnesemia:** Associated with hypocalcemia, hypokalemia, and neuromuscular irritability. - **Hypermagnesemia:** Results in skeletal muscle depression, hypotension, and respiratory depression. - **Acid-Base Balance:** Normal pH range is 7.35-7.45. Acids are formed as end products of metabolism. The body maintains pH through bicarbonate retention or acid excretion. Bones, lungs and kidneys are the major organs involved in the regulation of acid-base balance. The carbonic acid-bicarbonate system and hemoglobin are the most important plasma buffering systems. - **Acidosis:** pH is less than 7.35. - **Alkalosis:** pH is greater than 7.45. - **Respiratory Acidosis:** Elevation of PCO2 due to ventilation depression. - **Respiratory Alkalosis:** Depression of PCO2 due to hyperventilation. - **Metabolic Acidosis:** Depression of HCO3 or increase in noncarbonic acids. - **Metabolic Alkalosis:** Elevation of HCO3 due to excessive loss of metabolic acids. - **Anion Gap:** Used to distinguish different types of metabolic acidosis, and the normal anion gap is 10 to 12 mEq/L. **Innate and Adaptive Immunity** - **Innate Immunity:** - Provides natural barriers and the inflammatory response. - First line of defense includes physical and mechanical barriers (skin, mucous membranes, sloughing of cells, coughing, vomiting, urination) and biochemical barriers (antimicrobial peptides and normal microbiome). - Second line of defense is the inflammatory response, which is nonspecific, rapidly initiated, and without memory. Cardinal signs include redness, heat, swelling, pain, and loss of function. - **Vascular response:** Blood vessel dilation, increased vascular permeability, white blood cell (WBC) adherence, and migration. - **Plasma Protein Systems:** Three protein systems include the complement system, the clotting system, and the kinin system, all of which contain inactive enzymes that are sequentially activated. - **The Complement system** destroys pathogens and activates the inflammatory response through the classical, lectin, and alternative pathways. - **The Clotting System** forms a fibrinous mesh to prevent the spread of infection. - **The Kinin System** activates inflammatory cells, particularly bradykinin, which causes vasodilation, pain, and smooth muscle contraction. - **Cellular Mediators of Inflammation:** Include mast cells, granulocytes, monocytes and macrophages, natural killer (NK) cells, lymphocytes, and platelets. - **Pattern Recognition Receptors (PRRs):** Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs). - **Cytokines:** Chemokines or cytokines regulate the innate and adaptive immune response, and can be proinflammatory or antiinflammatory. Examples include interleukins (IL), interferons (IFN), and tumor necrosis factor (TNF). - **Mast Cells:** Release histamine through degranulation, which causes constriction of blood vessels and dilation of postcapillary venules. They also synthesize leukotrienes and prostaglandins. - **Endothelium:** Maintains normal blood flow, but during inflammation, it expresses receptors for leukocytes and retracts to allow fluid to pass into tissues. - **Platelets:** Stop bleeding and release granules. - **Phagocytes:** - **Neutrophils:** Predominate in early inflammatory responses and ingest bacteria. - **Eosinophils:** Defend against parasites and regulate vascular mediators. - **Basophils:** Similar to mast cells and are associated with allergies and asthma. - **Dendritic Cells:** Provide a link between innate and acquired immunity. - **Monocytes/Macrophages:** Monocytes mature into macrophages which are important initiators of inflammation and wound healing. - **Phagocytosis:** Is the process by which cells ingest and dispose of foreign material through opsonization, engulfment, phagosome formation, fusion with lysosomes, and destruction. - **Local Manifestations of Inflammation:** Heat, redness, swelling, pain, and loss of function. - **Exudative Fluids:** Serous, fibrinous, purulent, and hemorrhagic. - **Systemic Manifestations of Inflammation:** Fever, leukocytosis, and increased plasma protein synthesis (acute-phase reactants). - **Chronic Inflammation:** Lasts 2 weeks or longer and often involves dense infiltration of lymphocytes and macrophages, granuloma formation and giant cell formation. - **Wound Healing:** - **Regeneration, Resolution, and Repair:** Resolution restores original tissue, while repair replaces it with scar tissue. - **Phases:** Inflammation, reconstruction, and remodeling/maturation. - **Primary and Secondary Intention:** Primary involves minimal tissue loss, while secondary involves more tissue replacement. - **Dysfunctional Wound Healing:** Can result from ischemia, hemorrhage, hypovolemia, infection, malnutrition, impaired collagen assembly, impaired epithelialization, contractures and dehiscence. - **Pediatrics and Aging:** Neonates have depressed immune function, while older adults have impaired inflammation due to chronic illness and medications. - **Adaptive Immunity:** - Works with inflammation and recognizes non-self substances. Provides long-term protection, is slower, specific, and has memory. - End products are lymphocytes (T and B cells) and antibodies (immunoglobulins). - **Clonal Diversity:** Each lymphocyte recognizes one antigen, and occurs in the primary lymphoid organs. - **Clonal Selection:** Antigen is presented by antigen-presenting cells (APCs), leading to differentiation of B cells into plasma cells and T cells into effector cells. - **Humoral Immunity:** Involves B cells and circulating antibodies that protect against bacteria and viruses. - **Cellular Immunity:** Involves T cells, protecting against viruses and cancer. - **Active vs. Passive Immunity:** Active involves production of antibodies or T cells after exposure or immunization, while passive involves transfer of antibodies or T lymphocytes from a donor. - **Cluster of Differentiation (CD):** A labeling system used to identify families of proteins on many cells. - **Antigen:** A molecule that can react with antibodies or receptors on B and T cells. Immunogenicity depends on foreignness, size, complexity, and amount. - **Tolerance:** Recognizing self as not foreign, involving central and peripheral tolerance. - **Antibodies (Immunoglobulins):** Produced by plasma cells and include IgG, IgA, IgM, IgE, and IgD, each with different characteristics. - **IgG:** Most abundant and crosses placenta. - **IgA:** Found in body secretions. - **IgM:** Largest, and is the first antibody produced. - **IgD:** Located on B lymphocytes, and functions as an antigen receptor. - **IgE:** Involved in allergic reactions and defends against parasites. - **Molecular Structure:** Antibodies contain antigen-binding fragments (Fab) that bind antigens and crystalline fragments (Fc) that are responsible for biologic function. - **B-Cell Receptor (BCR):** Located on the surface of B cells and is responsible for antigen recognition and sending messages. - **T-Cell Receptor (TCR):** Located on the surface of T cells, contains accessory proteins, and is responsible for antigen recognition. - **Major Histocompatibility Complex (MHC):** Glycoproteins on cell surfaces, also known as human leukocyte antigens (HLA). Important for transplantation. - **CD1:** Antigen-presenting molecule for lipid antigens. - **Cytokines:** Chemical signals between cells, secreted by APCs and lymphocytes that increase the production of proteins and differentiation. - **Generation of Clonal Diversity:** Receptor specificities produced in the thymus (T cells) and bone marrow (B cells). - **B-Cell Maturation:** Occurs in bone marrow and includes development of surface markers and BCRs. Central and peripheral tolerance eliminates autoreactive B cells. - **T-Cell Maturation:** Occurs in the thymus with the development of TCRs and surface molecules. Includes CD4 cells (T-helper) and CD8 cells (cytotoxic). Central tolerance eliminates autoreactive T cells. - **Clonal Selection:** Produces effector cells (Th, plasma, and Tc cells) and memory cells. - **Secondary Lymphoid Organs:** Include the spleen, lymph nodes, tonsils, Peyer patches, and appendix. - **Antigen Processing and Presentation:** APCs process and present antigens, linking them with MHC molecules. Class I MHC presents endogenous antigens, and Class II presents exogenous antigens. - **T-Helper Lymphocytes (Th):** Help antigen-driven maturation of B and T cells. Subsets include Th1 (cell-mediated), Th2 (humoral), Th17 (inflammatory), and Treg (immune response limiting). - **B-Cell Clonal Selection:** Recognition of soluble antigen by BCRs leading to differentiation into plasma cells that produce antibodies. - **Primary and Secondary Immune Responses:** Primary occurs during initial exposure (lag phase) and secondary is a more rapid response due to memory cells. - **Cellular Interactions:** TCRs \"see\" processed and presented antigens, while BCRs react with soluble antigens. - **Class Switch (Isotype Switch):** B cells change the antibody class during clonal selection. T-independent antigens bypass Th cells and don\'t stimulate class switch. - **Cellular Differentiation:** B cells differentiate into plasma cells and memory cells. - **T-Cell Activation:** Initiates cellular immune response, and requires signals and cytokines. It involves direct killing of abnormal cells and activation of other immune cells. Superantigens cause an excessive production of cytokines. - **Antibody Functions:** Direct functions include neutralization, agglutination, and precipitation. Indirect functions involve complement and phagocytes. - **Secretory (Mucosal) Immune Response:** Lymphoid tissues protect external body surfaces, using IgA as the dominant immunoglobulin, preventing the invasion of pathogens. - **Immunoglobulin E (IgE):** Protects against parasitic worms and causes allergies. - **Killing Abnormal Cells:** Tc lymphocytes induce apoptosis through perforin, granzymes, and direct receptor interactions. NK cells kill abnormal cells that do not express MHC class I. - **T Cells Activate Macrophages:** T cells produce cytokines that activate macrophages during chronic inflammation. - **T-Regulatory Lymphocytes (Tregs):** Suppress the immune response to avoid attacking self. - **Fetal and Neonatal Immune Function:** Newborns have a poorly developed immune response with maternal antibodies providing immunity. - **Aging and Immune Function:** Decreased T cell activity, antibody production, and circulating memory B cells occur. **Endocrine** - **Functions:** Differentiation of reproductive and nervous systems, stimulation of growth and development, coordination of reproductive systems, and maintenance of the internal environment. - **Hormones:** Chemical messengers secreted by glands. They have specific secretion rates/rhythms, operate within feedback systems, affect cells with appropriate receptors, and are inactivated by the liver or kidneys. - **Regulation:** Hormones are released in response to alterations in the environment or to maintain a regulated level, and are controlled by chemical, endocrine, or neural factors through negative or positive feedback. - **Transport:** Water-soluble hormones circulate freely, while lipid-soluble hormones are bound to carrier proteins. (she emphasized this) - **Receptors:** Target cells recognize and bind with high affinity to hormones; the more receptors, the more sensitive the cell. Up-regulation increases the number of receptors, and down-regulation decreases them. Receptors can be located on the plasma membrane or in the intracellular compartment. - **Water Soluble Hormones:** High molecular weight and can\'t diffuse through the plasma membrane. - **Lipid Soluble Hormones:** Diffuse easily through the plasma membrane and bind to cytosolic or nuclear receptors. - **Signal Transduction:** This process communicates the message into the target cell using first and second messengers. - **First Messenger:** The hormone that carries the message to the target cell. - **Second Messengers:** Link the first signal to the inside of the cell, including cAMP, cGMP, and calcium (Ca++). - **Steroid (Lipid-Soluble) Hormones:** Synthesized from cholesterol (e.g., androgens, estrogens, glucocorticoids), and diffuse across plasma membranes and activate RNA polymerase and DNA transcription. - **Hormone Effects:** Hormones act on channel proteins to alter permeability, activate proteins through a second messenger system, or activate genes to cause protein synthesis. - **Hypothalamic-Pituitary Axis:** Hypothalamus and pituitary gland (anterior and posterior) form the structural and functional basis for integrating the neurologic and endocrine systems. - **Hypothalamus:** Produces releasing or inhibitory hormones. - **Anterior Pituitary:** Produces corticotropin-related hormones, glycoproteins, and somatomammotropins. - **Posterior Pituitary:** - Stores and secretes ADH (vasopressin) : controls plasma osmolality, causes water reabsorption - Secretes Oxytocin: causes uterine contractions and milk ejection for lactation. - **Pineal Gland:** Secrete melatonin to regulate circadian rhythms and reproductive systems. - **Thyroid and Parathyroid Glands:** The thyroid gland produces thyroid hormones and calcitonin (via the parafollicular \[C cells\]), which lowers serum calcium levels. The parathyroid glands produce parathyroid hormone (PTH) which regulates serum calcium. - **Regulation of Thyroid Hormone Secretion:** TRH stimulates the release of TSH, which increases the release of stored thyroid hormones, iodide uptake, thyroid hormone synthesis and prostaglandin secretion. - **Thyroid Hormones:** T4 (90% production) and T3 (10% production). Bound to thyroxine-binding globulin, prealbumin, lipoproteins or albumin. They affect growth, maturation, cell metabolism, heat production and cardiac function. - **Hypothyroid = TSH high, T-4 low** - **Hyperthyroid = Low TSH d/t high circulating thyroid hormone** - **Parathyroid Hormone (PTH):** Increases serum calcium and decreases phosphate, working with vitamin D to increase calcium absorption and is an antagonist of calcitonin. - **Endocrine Pancreas:** Produces glucagon (alpha cells) and insulin (beta cells), somatostatin (delta cells), and pancreatic polypeptide (F cells). - **Insulin:** Promoted by increased blood glucose, facilitates glucose uptake, potassium transport, and is an anabolic hormone. - **Amylin:** Co-secreted with insulin and regulates glucose by delaying gastric emptying and suppressing glucagon. - **Adrenal Glands:** Adrenal cortex (zona glomerulosa, fasciculata, reticularis) and medulla. The cortex is stimulated by ACTH. - **Adrenal Cortex:** Produces glucocorticoid hormones (cortisol, cortisone, corticosterone) that increase blood glucose, protein breakdown, are anti-inflammatory and decrease immune response. Mineralocorticoid hormones (aldosterone) affect ion transport and are regulated by the RAAS. - **Adrenal Medulla:** Secrete the catecholamines epinephrine and norepinephrine which promotes hyperglycemia as part of the \"fight or flight\" response. - **Neuroendocrine Response to Stressors:** Endocrine and nervous systems respond to stress, influenced by CRH from the hypothalamus. - **Tests of Endocrine Function:** Radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), and bioassay. - **Aging and the Endocrine System:** Thyroid gland atrophy, impaired glucose tolerance and diabetes, decreased growth hormone, and alterations in calcium balance occur. Decreased cortisol clearance, adrenal androgens and antidiuretic hormone (hyponatremia and SIADH) are also seen. **Key Concepts & Values:** - **K+ and Na+ transport:** Sodium-potassium (Na+/K+) pump maintains concentration gradients using ATP, transporting three Na+ ions out of the cell for every two K+ ions brought in. - **Anaerobic and Aerobic:** Glycolysis is an anaerobic process occurring in the cytoplasm that produces a net of 6 ATP per molecule of glucose. Oxidative phosphorylation occurs in the mitochondria, and is aerobic using carbohydrates, fats, and proteins to produce ATP. - **AMP, ATP, GTP:** ATP is the primary energy carrier. - **Hormones:** - **Antidiuretic Hormone (ADH):** Controls plasma osmolality, causing water reabsorption into the blood. - **Cortisol:** Increases blood glucose, and protein breakdown, antiinflammatory and decreases immune response. - **MHC:** Major histocompatibility complex, also known as HLA which are cell-surface glycoproteins that enable the immune system to distinguish between self and non-self. - **Cellular Injury:** Can lead to cell death by decreased ATP, failure of Na+/K+ pump, cellular swelling, detachment of ribosomes, etc. - **Changes in Osmotic Pressure:** Isotonic, hypotonic, and hypertonic alterations cause water movement between ICF and ECF, leading to cellular changes such as swelling or dehydration. - **Free Radicals:** Can cause cellular damage. Reactive oxygen species are produced during hypothermia. - **Electrolytes:** - **Calcium (Ca++):** Normal range is 8.5-12 mg/dL. - **Phosphate:** Most is in the bone. - **Potassium (K+):** Normal range is 3.5 - 5.5 mEq/L. - **Sodium (Na+):** Normal range is 135-147 mEq/L. - **Calcitonin:** Lowers serum calcium. - **Vitamin D:** Increases calcium absorption from the GI tract. - **Thyroid Hormone (T3/T4):** Regulates metabolism. - **Parathyroid Hormone (PTH):** Increases serum calcium. - **Vasopressin (ADH):** Controls plasma osmolality. - **Epinephrine:** Catecholamine that promotes hyperglycemia and is part of the \"fight or flight\" response. - **Aldosterone:** Affects ion transport and causes sodium retention and potassium and hydrogen loss. - **Acid/Base, Blood Gases:** Normal arterial blood pH is 7.35-7.45. Acidosis is pH \< 7.35, while alkalosis is pH \> 7.45. - **Edema:** Caused by decreased plasma oncotic pressure, increased capillary permeability, lymph obstruction, or sodium retention. Natriuretic peptides decrease tubular reabsorption and promote sodium excretion. - **RAAS (Renin-Angiotensin-Aldosterone System):** Regulates blood pressure and fluid balance. - **Albumin:** Major plasma protein that contributes to oncotic pressure. - **Arachidonic Acid Cascade:** Leads to production of prostaglandins and leukotrienes, which contribute to pain and inflammation. - **Natural Killer (NK) Cells:** Eliminate cells infected with viruses and cancer cells in the blood. - **Cytokines:** Regulate innate and adaptive immunity and can be pro- or anti-inflammatory. Examples include interleukins (IL) and interferons (IFN). - **WBC Differentials:** Neutrophils are predominant in early inflammation and phagocytosis, monocytes mature into macrophages, eosinophils defend against parasites, and basophils have a role in allergies. - **NO (Nitric Oxide):** Maintains blood flow and pressure and inhibits platelet activation. - **Mast Cells:** Release histamine, leukotrienes and prostaglandins. - **Antigens:** Molecules that react with antibodies or lymphocyte receptors. - **Antibodies:** Immunoglobulins (IgG, IgA, IgM, IgE, IgD) produced by plasma cells. - **Lipid and Water-Soluble Hormones:** Water-soluble hormones circulate freely and lipid-soluble hormones bind to transport proteins. Lipid soluble hormones include steroids, and diffuse across the cell membrane, whereas water-soluble hormones bind to membrane receptors. - **Mineralocorticoid Steroids:** Affect ion transport, like aldosterone causing sodium retention. - **Glucocorticoid Steroids:** Increase blood glucose, protein breakdown, and have anti-inflammatory effects, like cortisol. - **Energy Production in the Body:** Glycolysis (anaerobic, in the cytoplasm) and oxidative phosphorylation (aerobic, in the mitochondria). - **Decompression Sickness:** Not specifically mentioned in the provided sources. - **Coagulation Cascade:** A series of steps involving clotting factors that result in the formation of a fibrin mesh to stop bleeding.