chapter 44 Outline: Osmoregulation and Excretion

Chapter 44 – Osmoregulation and Excretion
OSMOREGULATION: The regulation of solute and water concentrations in body fluids by organisms living in hyperosmotic, hypoosmotic, and terrestrial environments.
EXCRETION: The disposal of nitrogen-containing waste products of metabolism.
TRANSPORT EPITHELIUM: One or more layers of specialized epithelial cells that regulate solute movements.
NITROGENOUS WASTES: Simple nitrogen compounds produced by the metabolism of proteins, such as urea and uric acid.
AMMONIA: A small, very toxic molecule made up of three hydrogen atoms and one nitrogen atom; produced by nitrogen fixation and as a metabolic waste product of protein and nucleic acid metabolism.
UREA: A soluble nitrogenous waste excreted by mammals, most adult amphibians, and many marine fishes and turtles; produced in the liver by a metabolic cycle that combines ammonia with carbon dioxide.
URIC ACID: An insoluble precipitate of nitrogenous waste excreted by land snails, insects, birds, and some reptiles.
FILTRATION: In the vertebrate kidney, the extraction of water and small solutes, including metabolic wastes, from the blood by the nephrons.
FILTRATE: Fluid extracted by the excretory system from the blood or body cavity. The excretory system produces urine from the filtrate after extracting valuable solutes from it and concentrating it.
SELECTIVE REABSORPTION: The selective uptake of solutes from a filtrate of blood, coelomic fluid, or hemolymph in the excretory organs of animals.
SECRETION: (1) The discharge of molecules synthesized by a cell. (2) In the vertebrate kidney, the discharge of wastes from the blood into the filtrate from the nephron tubules.
EXCRETION: The disposal of nitrogen-containing waste products of metabolism.
Draw, label, and summarize the key functions of the excretory systems (Fig 44.9, p.929) : Most excretory systems produce a filtrate by pressure–filtering body fluids and then modify the filtrate′s contents. This diagram is modeled after the vertebrate excretory system.

Vertebrate / Mammalian (i.e. human) URINARY SYSTEM: the organs and passageways concerned with the production and excretion of urine, including the kidneys, ureters, urinary bladder and the urethra.
RENAL ARTERY: The blood vessel bringing blood to the kidney.
RENAL VEIN: The blood vessel draining the kidney.
URETER: A duct leading from the kidney to the urinary bladder.
URINARY BLADDER: The pouch where urine is stored prior to elimination.
URETHRA: A tube that releases urine from the body near the vagina in females and through the penis in males; also serves in males as the exit tube for the reproductive system.
RENAL CORTEX: The outer portion of the vertebrate kidney.
RENAL MEDULLA: The inner portion of the vertebrate kidney, beneath the renal cortex.
NEPHRON: The tubular excretory unit of the vertebrate kidney.
GLOMERULUS: A ball of capillaries surrounded by Bowman뭩 capsule in the nephron and serving as the site of filtration in the vertebrate kidney.
BOWMAN’S CAPSULE: A cup-shaped receptacle in the vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood.
PROXIMAL TUBULE: In the vertebrate kidney, the portion of a nephron immediately downstream from Bowman뭩 capsule that conveys and helps refine filtrate.
DESCENDING AND ASCENDING LIMB OF THE LOOP OF HENLE: The long hairpin turn, with a descending and ascending limb, of the renal tubule in the vertebrate kidney; functions in water and salt reabsorption.
DISTAL TUBULE: In the vertebrate kidney, the portion of a nephron that helps refine filtrate and empties it into a collecting duct.
COLLECTING DUCT: The location in the kidney where filtrate from renal tubules is collected; the filtrate is now called urine.
RENAL PELVIS: Funnel-shaped chamber that receives processed filtrate from the vertebrate kidney뭩 collecting ducts and is drained by the ureter.
CORTICAL NEPHRONS: Nephrons located almost entirely in the renal cortex. These nephrons have a reduced loop of Henle.
JUXTAMEDULLARY NEPHRONS: Nephrons with well-developed loops of Henle that extend deeply into the renal medulla.
AFFERENT ARTERIOLE: The blood vessel supplying a nephron.
EFFERENT ARTERIOLE: The blood vessel draining a nephron.
VASA RECTA: The capillary system that serves the loop of Henle.
Describe/explain the COUNTERCURRENT MULTIPLIER SYSTEM (a picture might help!): A countercurrent system in which energy is expended in active transport to facilitate exchange of materials and create concentration gradients. For example, the loop of Henle actively transports NaCl from the filtrate in the upper part of the ascending limb of the loop, making the urine-concentrating function of the kidney more effective.

ANTIDIURETIC HORMONE (ADH): A hormone produced in the hypothalamus and released from the posterior pituitary. It promotes water rentention by the kidneys as part of an elaborate feedback scheme that helps regulate the osmolarity of the blood.
ALDOSTERONE: An adrenal hormone that acts on the distal tubules of the kidney to stimulate the reabsorption of sodium (Na+) and the passive flow of water from the filtrate.
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS): A part of a complex feedback circuit that normally partners with antidiuretic hormone in osmoregulation.

chapter 43 Outline: The Immune System

Chapter 43 – The Immune System
PATHOGEN: A disease-causing agent.
INNATE IMMUNITY: The kind of defense that is mediated by phagocytic cells, antimicrobial proteins, the inflammatory response, and natural killer (NK) cells. It is present before exposure to pathogens and is effective from the time of birth.
ACQUIRED/ADAPTIVE IMMUNITY: The kind of defense that is mediated by B lymphocytes (B cells) and T lymphocytes (T cells). It exhibits specificity, memory, and self-nonself recognition. Also called adoptive immunity.
LYMPHOCYTES: A type of white blood cell that mediates acquired immunity. Lymphocytes that complete their development in the bone marrow are called B cells, and those that mature in the thymus are called T cells.
ANTIBODIES: A protein secreted by plasma cells (differentiated B cells) that binds to a particular antigen and marks it for elimination; also called immunoglobulin. All antibody molecules have the same Y-shaped structure and in their monomer form consist of two identical heavy chains and two identical light chains joined by disulfide bridges.
INNATE IMMUNITY: The kind of defense that is mediated by phagocytic cells, antimicrobial proteins, the inflammatory response, and natural killer (NK) cells. It is present before exposure to pathogens and is effective from the time of birth.
External Defenses (1st line): A break in the skin.
SKIN: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis.
MUCOUS: Smooth moist epithelium that lines the digestive tract and air tubes leading to the lungs.
OIL & SWEAT GLANDS: give the skin a pH ranging from 3 to 5, which is acidic enough to prevent colonization by many microbes. (Bacteria that normally inhabit the skin are adapted to its acidic, relatively dry environment.)
LYSOZYMES: An enzyme in sweat, tears, and saliva that attacks bacterial cell walls.
Internal Cellular & Chemical Defenses:
PHAGOCYTOSIS: A type of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells.
PHAGOCYTIC LEUCOCYTES (WBCs): A white blood cell; typically functions in immunity, such as phagocytosis or antibody production.
COMPLEMENT SYSTEM: yet another example of how life is protein dependant! A group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse pathogens. The complement system is activated in a cascade initiated by surface antigens on microorganisms or by antigen-antibody complexes.
INTERFERONS: A protein that has antiviral or immune regulatory functions. Interferon ? and interferon-??, secreted by virus-infected cells, help nearby cells resist viral infection; interferon-??, secreted by T cells, helps activate macrophages.
DEFENSINS:
INFLAMMATORY RESPONSE: A localized innate immune defense triggered by physical injury or infection of tissue in which changes to nearby small blood vessels enhance the infiltration of white blood cells, antimicrobial proteins, and clotting elements that aid in tissue repair and destruction of invading pathogens; may also involve systemic effects such as fever and increased production of white blood cells.
ACQUIRED/ADAPTIVE IMMUNITY: acquired immunity is immunological memory—the ability to respond more quickly to a particular invader or foreign tissue the second time it is encountered.
CYTOKINES: Any of a group of proteins secreted by a number of cell types, including macrophages and helper T cells, that regulate the function of lymphocytes and other cells of the immune system.
ANTIGEN: A macromolecule that elicits an immune response by lymphocytes.
EPITOPE: A small, accessible region of an antigen to which an antigen receptor or antibody binds; also called an antigenic determinant.
LYMPHOCYTES: A type of white blood cell that mediates acquired immunity. Lymphocytes that complete their development in the bone marrow are called B cells, and those that mature in the thymus are called T cells.
B CELLS: what are they, what do they do, how did they get their name? A type of lymphocyte that develops to maturity in the bone marrow. After encountering antigen, B cells differentiate into antibody-secreting plasma cells, the effector cells of humoral immunity.
T CELLS: what are they, what do they do, how did they get their name? A type of lymphocyte, including the helper T cells and cytotoxic T cells, that develops to maturity in the thymus. After encountering antigen, T cells are responsible for cell-mediated immunity.
ANTIGEN RECEPTORS: what are they and how do they differ between B & T cells The general term for a surface protein, located on B cells and T cells, that binds to antigens, initiating acquired immune responses. The antigen receptors on B cells are called B cell receptors (or membrane immunoglobulins), and the antigen receptors on T cells are called T cell receptors.
ANTIGEN PRESENTATION: The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell.
ANTIGEN-PRESENTING CELLS [MACROPHAGES]: A cell that ingests bacteria and viruses and destroys them, generating peptide fragments that are bound by class II MHC molecules and subsequently displayed on the cell surface to helper T cells. Macrophages, dendritic cells, and B cells are the primary antigen-presenting cells.
Clonal Selection of Lymphocytes: also see figure 43.12
MEMORY CELLS: One of a clone of long-lived lymphocytes, formed during the primary immune response, that remains in a lymphoid organ until activated by exposure to the same antigen that triggered its formation. Activated memory cells mount the secondary immune response.
CLONAL SELECTION: The process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen. The selected lymphocytes proliferate and differentiate into a clone of effector cells and a clone of memory cells specific for the stimulating antigen. Clonal selection accounts for the specificity and memory of acquired immune responses.
PRIMARY IMMUNE RESPONSE: The initial acquired immune response to an antigen, which appears after a lag of about 10 to 17 days.
PLASMA CELLS: The antibody-secreting effector cell of humoral immunity; arises from antigen-stimulated B cells.
SECONDARY IMMUNE RESPONSE: The acquired immune response elicited on second or subsequent exposures to a particular antigen. The secondary immune response is more rapid, of greater magnitude, and of longer duration than the primary immune response.
HUMORAL IMMUNE RESPONSE: The branch of acquired immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.
CELL-MEDIATED IMMUNE RESPONSE: The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells, cancer cells, and transplanted cells.
HELPER T CELL: A type of T cell that, when activated, secretes cytokines that promote the response of B cells (humoral response) and cytotonic T cells (cell-mediated response) to antigens.
MONOCLONAL ANTIBODIES: Any of a preparation of antibodies that have been produced by a single clone of cultured cells and thus are all specific for the same epitope.
ACTIVE IMMUNITY: Long-lasting immunity conferred by the action of a person뭩 B cells and T cells and the resulting B and T memory cells specific for a pathogn. Active immunity can develop as a result of natural infection or immunization.
IMMUNIZATION (VACCINATION) = ARTIFICIAL IMMUNITY: acquired (active or passive) immunity produced by deliberate exposure to an antigen, as in vaccination.
PASSIVE IMMUNITY: Short-term immunity conferred by the administration of ready-made antibodies or the transfer of maternal antibodies to a fetus or nursing infant; lasts only a few weeks or months because the immune system has not been stimulated by antigens.
NATURAL IMMUNITY: immunity due to infection.
ANAPHYLACTIC SHOCK: An acute, whole-body, life-threatening, allergic response.
IMMUNODEFICIENCIES: Immunodeficiency disorders are a group of disorders in which part of the immune system is missing or defective. Therefore, the body's ability to fight infections is impaired. As a result, the person with an immunodeficiency disorder will have frequent infections that are generally more severe and last longer than usual.
AUTOIMMUNE DISEASES: An immunological disorder in which the immune system turns against self.
HUMAN IMMUNODEFICIENCY VIRUS (HIV): The infectious agent that causes AIDS. HIV is a retrovirus.