Immunology and Reproductive System Flashcards

Study Guide 6 Ch. 24 The Immune System

Definitions

• Antibiotics: Medications used to fight bacterial infections. They work by killing bacteria or inhibiting their growth. Common examples include penicillin, amoxicillin, and tetracycline. Antibiotics are effective against bacteria but not against viruses.

• Nonspecific immunity (Skin): Also known as innate immunity, it includes defenses that are always active and protect against a wide range of pathogens. The skin acts as a physical barrier, preventing the entry of pathogens. Additional nonspecific defenses include mucous membranes, which trap pathogens, and antimicrobial substances like lysozyme in tears and saliva.

• Actively acquired immunity: Immunity that develops after exposure to an antigen, either through natural infection or vaccination. This type of immunity involves the production of antibodies and activation of immune cells specifically targeted against the antigen. Active immunity is long-lasting and provides immunological memory.

• Chemotaxins: Chemicals that attract immune cells (e.g., neutrophils, macrophages) to the site of infection or inflammation. They guide these cells along a concentration gradient towards the source of the chemical signal. Examples of chemotaxins include cytokines, chemokines, and complement fragments.

• Opsonins: Molecules (e.g., antibodies, complement proteins) that enhance phagocytosis by marking pathogens for destruction. They bind to the pathogen and are then recognized by receptors on phagocytes, facilitating engulfment. Opsonization increases the efficiency of phagocytosis.

• Pyrogen: A substance, typically produced by a bacterium, that causes fever. Pyrogens affect the hypothalamus, the thermoregulatory center of the brain, leading to an increase in body temperature. Examples of pyrogens include bacterial endotoxins and certain cytokines.

• Helper T cells: A type of T lymphocyte that helps activate other immune cells, including B cells and cytotoxic T cells. They release cytokines that stimulate the immune response. Helper T cells are also known as CD4+ T cells.

• T lymphocytes: Also known as T cells, these are a type of white blood cell that plays a central role in cell-mediated immunity. They recognize and respond to specific antigens presented on the surface of cells. T cells mature in the thymus.

• Allergies: Inappropriate or exaggerated immune responses to harmless substances (allergens). These responses involve the production of IgE antibodies and the activation of mast cells, leading to the release of inflammatory mediators. Common allergens include pollen, dust mites, and certain foods.

• Autoimmune diseases: Conditions in which the immune system mistakenly attacks the body's own tissues or cells. Examples include rheumatoid arthritis, multiple sclerosis, and type 1 diabetes. Autoimmune diseases can affect various organs and tissues in the body.

• Cell-mediated immunity: An immune response that does not involve antibodies but rather involves the activation of T cells, which directly kill infected cells or activate other immune cells.

Explanations in Detail

• Inflammation:
  - A localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.
  - Involves:
  - Vasodilation: widening of blood vessels, increasing blood flow to the area.
  - Increased vascular permeability: allows fluid and immune cells to move into the tissue.
  - Recruitment of immune cells: chemotaxins attract neutrophils and macrophages.
  - Release of inflammatory mediators: histamine, cytokines, and prostaglandins contribute to the inflammatory response. These mediators lead to increased pain sensitivity and promote further inflammation.

• All five different types of immunoglobulins and their functions:
  - IgG:
  - Most abundant antibody in serum.
  - Provides long-term immunity.
  - Crosses the placenta to provide passive immunity to the fetus. This provides protection to the newborn during the first few months of life.
  - IgM:
  - First antibody produced during an immune response.
  - Effective at activating complement. Complement activation leads to the formation of the membrane attack complex (MAC), which lyses pathogens.
  - Exists as a pentamer (five antibody molecules joined together). This structure enhances its ability to bind to multiple antigens.
  - IgA:
  - Found in mucosal secretions (e.g., saliva, tears, breast milk).
  - Provides protection against pathogens at mucosal surfaces. It prevents the attachment of pathogens to mucosal cells.
  - Exists as a dimer (two antibody molecules joined together) in secretions. This dimeric form is stabilized by a J chain.
  - IgE:
  - Involved in allergic reactions and parasitic infections.
  - Binds to mast cells and basophils, triggering the release of histamine and other inflammatory mediators. Histamine causes vasodilation, increased vascular permeability, and bronchoconstriction.
  - IgD:
  - Found on the surface of B cells.
  - Plays a role in B cell activation. It acts as a receptor for antigens on B cells.

• All five different types of white blood cells and their functions:
  - Neutrophils:
  - Most abundant type of white blood cell.
  - Phagocytic cells that engulf and destroy bacteria and fungi. They use enzymes and reactive oxygen species to kill pathogens.
  - First responders to infection. They are recruited to the site of infection by chemotaxins.
  - Lymphocytes:
  - Include T cells, B cells, and natural killer (NK) cells.
  - T cells: involved in cell-mediated immunity. They recognize and kill infected cells.
  - B cells: produce antibodies. Antibodies neutralize pathogens and mark them for destruction.
  - NK cells: kill infected or cancerous cells. They recognize cells that do not express MHC class I molecules.
  - Monocytes:
  - Phagocytic cells that differentiate into macrophages and dendritic cells.
  - Macrophages: engulf and destroy pathogens and cellular debris. They also present antigens to T cells.
  - Dendritic cells: antigen-presenting cells that activate T cells. They capture antigens in peripheral tissues and migrate to lymph nodes to activate T cells.
  - Eosinophils:
  - Involved in defense against parasitic infections and allergic reactions.
  - Release cytotoxic granules that damage parasites. These granules contain enzymes and toxins that kill parasites.
  - Basophils:
  - Release histamine and other inflammatory mediators.
  - Involved in allergic reactions. They are similar to mast cells but circulate in the blood.

Ch. 26 Reproductive and Development

Definitions

• SRY: Sex-determining region Y protein. A gene located on the Y chromosome that plays a key role in determining sex. It initiates the development of testes in males. Without SRY, thedefault developmental pathway is female.

• Müllerian ducts: Precursors to the female reproductive tract. They develop into the uterus, fallopian tubes, and upper part of the vagina in females. The development of Müllerian ducts is inhibited by Müllerian-inhibiting substance (MIS) in males.

• Wolffian duct: Precursors to the male reproductive tract. They develop into the epididymis, vas deferens, and seminal vesicles in males. The development of Wolffian ducts is stimulated by testosterone.

• Leydig cells: Interstitial cells in the testes that produce testosterone in response to luteinizing hormone (LH). Testosterone is essential for the development of male secondary sexual characteristics.

• Cryptorchidism: Failure of one or both testes to descend into the scrotum. This condition can lead to infertility and increases the risk of testicular cancer.

• Seminiferous tubules: Coiled tubes within the testes where spermatogenesis (sperm production) occurs. Sertoli cells within the seminiferous tubules support sperm development.

• Bulbourethral glands: Also known as Cowper's glands. Small glands located near the urethra that secrete a clear, alkaline mucus that lubricates the urethra and neutralizes acidic residues from urine prior to ejaculation. This helps to protect sperm from damage.

• Capacitation: The physiological changes spermatozoa must undergo in the female reproductive tract to gain the ability to penetrate and fertilize an egg. Capacitation involves the removal of cholesterol from the sperm membrane and changes in membrane potential.

• Fallopian tube: Also known as the oviduct. The tube through which the egg travels from the ovary to the uterus. Fertilization typically occurs in the fallopian tube. The fallopian tube is lined with ciliated cells that help to propel the egg towards the uterus.

• Fimbriae: Finger-like projections at the end of the fallopian tube near the ovary that help to capture the egg after ovulation. The fimbriae create currents that draw the egg into the fallopian tube.

• Corpus luteum: A temporary endocrine gland formed in the ovary after ovulation from the ovarian follicle. It secretes progesterone and estrogen, which help to maintain the uterine lining during early pregnancy. If fertilization does not occur, the corpus luteum degenerates.

• Human chorionic gonadotropin (hCG): A hormone produced by the placenta after implantation. It helps to maintain the corpus luteum and prevent menstruation during pregnancy. Its presence in urine is the basis of pregnancy tests.

Explanations in Detail

• The number of chromosomes in haploid cells, like sperms or eggs:
  - Haploid cells (sperm and eggs) contain half the number of chromosomes as diploid cells (somatic cells).
  - In humans, diploid cells have 2n = 46 chromosomes, while haploid cells have n = 23 chromosomes. During fertilization, the fusion of a sperm and an egg restores the diploid number of chromosomes.

• The endocrine pathway to produce sperms and eggs:
  - Sperm production:
  1. Hypothalamus releases gonadotropin-releasing hormone (GnRH).
  2. GnRH stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
  3. FSH stimulates Sertoli cells in the seminiferous tubules to support sperm development. Sertoli cells provide nutrients and growth factors to developing sperm.
  4. LH stimulates Leydig cells to produce testosterone.
  5. Testosterone promotes spermatogenesis and the development of secondary sexual characteristics. It also provides negative feedback to the hypothalamus and anterior pituitary.
  - Egg production:
  1. Hypothalamus releases GnRH.
  2. GnRH stimulates the anterior pituitary to release FSH and LH.
  3. FSH stimulates the development of ovarian follicles. Follicles contain the developing oocyte and produce estrogen.
  4. As follicles mature, they produce estrogen.
  5. Estrogen triggers a surge of LH, which induces ovulation. The LH surge also promotes the completion of meiosis I in the oocyte.
  6. After ovulation, the ruptured follicle becomes the corpus luteum, which produces progesterone and estrogen. Progesterone prepares the uterine lining for implantation.

• The ovarian, uterine, and menstrual cycles:
  - Ovarian cycle:
  - Follicular phase: FSH stimulates follicle development, leading to increased estrogen production. The follicular phase lasts from day 1 to day 14 of the menstrual cycle.
  - Ovulation: LH surge triggers the release of the egg from the dominant follicle. Ovulation typically occurs around day 14 of the menstrual cycle.
  - Luteal phase: Corpus luteum forms and produces progesterone and estrogen. The luteal phase lasts from day 14 to day 28 of the menstrual cycle.
  - Uterine cycle:
  - Menstrual phase: Shedding of the uterine lining (endometrium) due to low levels of estrogen and progesterone. Menstruation typically lasts for 3-7 days.
  - Proliferative phase: Endometrium thickens in response to estrogen. This phase lasts from the end of menstruation to ovulation.
  - Secretory phase: Endometrium becomes more vascular and glandular in response to progesterone and estrogen. This phase prepares the uterus for implantation and lasts from ovulation to the start of menstruation.
  - Menstrual cycle:
  - Approximately 28 days long

#### Study Guide 6 Ch. 24 The Immune System ##### Definitions - **Antibiotics:** Fight bacterial infections by killing or inhibiting bacteria; ineffective against viruses. - **Nonspecific immunity (Skin):** Innate, always active defense against a wide range of pathogens. Skin is a physical barrier; mucous membranes trap pathogens. - **Actively acquired immunity:** Develops after exposure to an antigen through infection or vaccination, creating antibodies and immunological memory. - **Chemotaxins:** Chemicals attracting immune cells to infection sites. - **Opsonins:** Molecules enhancing phagocytosis by marking pathogens for destruction. - **Pyrogen:** Substance causing fever, affecting the hypothalamus. - **Helper T cells:** Activate other immune cells, releasing cytokines; also known as CD4+ T cells. - **T lymphocytes:** White blood cells in cell-mediated immunity, recognizing and responding to antigens; mature in the thymus. - **Allergies:** Exaggerated immune responses to harmless allergens, involving IgE antibodies and mast cell activation. - **Autoimmune diseases:** Immune system attacks body's own tissues, like rheumatoid arthritis and type 1 diabetes. - **Cell-mediated immunity:** Immune response via T cells, directly killing infected cells or activating other immune cells. <!-- --> ##### Explanations in Detail - **Inflammation:** Localized condition with redness, swelling, heat, and pain. Involves vasodilation, increased vascular permeability, immune cell recruitment, and release of inflammatory mediators. - **Immunoglobulins:** - **IgG:** Most abundant, provides long-term immunity, crosses the placenta. - **IgM:** First produced, activates complement, exists as a pentamer. - **IgA:** In mucosal secretions, protects against pathogens at mucosal surfaces, exists as a dimer. - **IgE:** Involved in allergic reactions and parasitic infections, triggers histamine release. - **IgD:** On B cells, plays a role in B cell activation. - **White blood cells:** - **Neutrophils:** Most abundant, phagocytic, first responders. - **Lymphocytes:** T cells (cell-mediated immunity), B cells (produce antibodies), NK cells (kill infected/cancerous cells). - **Monocytes:** Differentiate into macrophages (phagocytize, present antigens) and dendritic cells (activate T cells). - **Eosinophils:** Defend against parasitic infections and allergic reactions; release cytotoxic granules. - **Basophils:** Release histamine and inflammatory mediators; involved in allergic reactions. <!-- --> #### Ch. 26 Reproductive and Development ##### Definitions - **SRY:** Sex-determining region Y protein; initiates testes development in males. - **Müllerian ducts:** Precursors to female reproductive tract; develop into uterus, fallopian tubes, and upper vagina. - **Wolffian duct:** Precursors to male reproductive tract; develop into epididymis, vas deferens, and seminal vesicles. - **Leydig cells:** Produce testosterone in testes in response to LH. - **Cryptorchidism:** Failure of testes to descend into scrotum. - **Seminiferous tubules:** Site of spermatogenesis in testes. - **Bulbourethral glands:** Secrete alkaline mucus to lubricate urethra. - **Capacitation:** Changes spermatozoa undergo to fertilize an egg. - **Fallopian tube:** Tube for egg travel from ovary to uterus; fertilization site. - **Fimbriae:** Capture egg after ovulation. - **Corpus luteum:** Secretes progesterone and estrogen after ovulation. - **Human chorionic gonadotropin (hCG):** Maintains corpus luteum during pregnancy; basis of pregnancy tests. <!-- --> ##### Explanations in Detail - **Haploid cells:** Sperm and eggs, contain n = 23 chromosomes. - **Sperm production:** Hypothalamus releases GnRH → anterior pituitary releases FSH and LH → FSH stimulates Sertoli cells → LH stimulates Leydig cells → Testosterone promotes spermatogenesis. - **Egg production:** Hypothalamus releases GnRH → anterior pituitary releases FSH and LH → FSH stimulates follicle development → Estrogen increases → LH surge induces ovulation → Corpus luteum produces progesterone and estrogen. - **Ovarian cycle:** Follicular phase (follicle development, estrogen), Ovulation (egg release), Luteal phase (corpus luteum). - **Uterine cycle:** Menstrual phase (shedding of endometrium), Proliferative phase (endometrium thickens), Secretory phase (uterus prepares for implantation). - **Menstrual cycle:** Approximately 28 days.