Life 103 Week 14
Life 103 Week 14 LIFE 103
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This 5 page Class Notes was uploaded by Caroline Hurlbut on Friday April 29, 2016. The Class Notes belongs to LIFE 103 at Colorado State University taught by Jennifer L Neuwald; Tanya Anne Dewey in Fall 2016. Since its upload, it has received 12 views. For similar materials see Biology of Organisms-Animals and Plants in Biology at Colorado State University.
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Date Created: 04/29/16
The Immune System immunization - process of generating an immune response in an individual in order • to protect against disease • inoculation - exposure to a disease agent in order to prompt a reduced infection and then immunity from the disease • vaccination - exposure to dead or altered disease agents to induce an immune reaction that confers immunity to a disease, developed by Edward Jenner • herd immunity - largest proportion of community is immune (cannot get or carry the disease)—>probability that people who are not immune will contract the disease is reduced • barrier defenses prevent things from entering the body —skin: primary barrier —mucous membranes: trap pathogens in mucous —secretions: lysozymes destroy cell walls of some bacteria —acidic body pH: acidity kills many pathogens • job of immune system —prevent entry of pathogens —distinguish and detect entry of pathogens —eliminate pathogens • innate immune system - ﬁrst responders, general (all animals) • adaptive immune system - requires activation, more speciﬁc (vertebrates only) • TLR receptors bind to alien molecules and trigger phagocytosis cellular innate defenses • —neutrophils —macrophages —dendritic cells: stimulate adaptive immune system when activated —natural killer cells • aspects of innate immune system —antimicrobial proteins —inﬂammatory response • antigen - foreign substance that induces immune response in lymphocytes (adaptive immune system) 2 types of lymphocytes • —B cells: interact directly with antigens by speciﬁc binding (each B cell bonds to 1 kind of antigen) —T cells: don’t interact directly with antigens, use dendritic cells for speciﬁc binding • B cell activation process —clonal selection —some members of proliferation produce antibodies —memory B cells • T cell activation process —clonal selection —some members of proliferation produce helper and cytotoxic T cells —memory T cells • characteristics of adaptive immunity —diversity of lymphocytes and receptors —self-tolerance —cell proliferation (clonal selection) —immunological memory: adaptive, result of memory cells • improper immune system function —allergies —autoimmune diseases —immunodeﬁciency • hygiene hypothesis - lack of exposure to infections suppresses development of immune system Offspring • asexual reproduction - no fusion of gametes—>offspring genetically identical to parent —binary ﬁssion: parent cell divides into 2 via mitosis —budding: offspring form from outgrowths of parent —fragmentation: offspring grows from part of parent —parthenogenesis: offspring form from unfertilized egg • sexual reproduction - fusion of gametes formed via meiosis—>offspring has combination of genes from both parents • cost of asexual reproduction —offspring genetically identical to parents • beneﬁts of asexual reproduction —one sex—>every individual can reproduce —offspring genetically identical to parents (can be beneﬁcial in the right environment) • cost of sexual reproduction —2 sexes—>halves # of organisms that can have offspring —ﬁnd mates (correct species, gender, timing, etc.) —offspring represent only 50% of parental genes —mating can be dangerous • beneﬁt of sexual reproduction —genetically variable offspring—>survival more likely • why sex? —recombination A. combine beneﬁcial mutations B. avoid effects of deleterious mutations C. generate novel genotypes —red queen hypothesis: reduce susceptibility to parasites, diseases, or predators—>co-evolutionary “arms race” —remove deleterious mutations from lineage • sexual reproduction occurs in new/changing environments • asexual reproduction occurs inconstant/unchanging environments • if death is random and all else is equal, asexual reproduction is favored • if death is not random, sexual reproduction is favored • hormonal control of sexual reproduction: hormones regulate sexual behavior, such as courtship displays, aggression, parental care, etc. • pheromonal control of reproduction —used to communicate sexual receptivity and convey individual information —used in social control to suppress the reproductive activity of conspeciﬁcs • challenges of producing offspring —generate gametes —ﬁnd mate —fertilization —developmental support • anisogamy - pattern of dimorphism between gametes —female eggs: smaller #, higher investment —male sperm: larger #, lower investment • ﬁnding a mate —sessile species have difﬁculty mating—>modiﬁed reproduction organ —danger of interacting with potential mate (ex. female spiders eat the male) —hermaphroditism • fertilization —external: requires water —internal: requires intermittent organ and cooperation and coordination of reproductive anatomies • support during development —pre-hatching/birth A. nutrition supplied to developing embryo (yolk, gestation, etc.) B. protection (nests, gestation, guarding, etc.) —post-hatching/birth A. nourishment (lactation) B. protection C. teaching • sequential hermaphroditism in ﬁsh: both sexes during lifetime, one sex at a time —protandrous: male ﬁrst A. larger body mass—>produce more eggs —protogynous: female ﬁrst A. larger body mass—>better ability to control resources in territory and have multiple mates Hormones & Chemical Signaling • anti-diuretic hormone (ADH, vasopressin) - retain water in body tissues by increasing absorption of ﬂuids in the collecting duct of the nephron —hypothalamus detects increases osmolarity of blood —nerve impulse sent to pituitary gland—>secretes ADH —ADH receptors in kidney • integration between nervous system and endocrine system—>negative feedback mechanism—>homeostasis maintained chemical signals act on distant tissues (collecting duct and distal tubule) • • modes of chemical signaling —autocrine: local, secreting cells are also target cells —paracrine: local, target cells are near diffusing cells —*endocrine: global, endocrine glands secrete hormones into bloodstream to reach target cells anywhere in the body —synaptic: local, neurotransmitters diffuse across synapses —*neuroendocrine: global, neurons secrete hormones into bloodstream to reach target cells anywhere endocrine system - discontinuous set of glands that secrete hormones into • bloodstream —endocrine: ductless gland secreting into blood —exocrine: ducted glands secreting onto surfaces or into body cavities —functions A. maintain homeostasis B. integrate and regulate growth and development C. control sexual reproduction • hormone - chemical secreted into the bloodstream that travels to have an impact on speciﬁc target cells • hormones have large impacts at low concentrations —signal transduction: transmission of signals from cell exterior to interior —ampliﬁcation: signals can be ampliﬁed at any step • hormone solubility inﬂuences signal transduction —water soluble: cannot diffuse through plasma membrane, requires receptor proteins on cell surface —lipid soluble: can diffuse through plasma membranes • pheromones - chemicals secreted in body ﬂuids to inﬂuence behavior of other individuals —involve communication between individuals instead of cells • multiple impacts of hormones with same or different receptors, response varies with target tissue type
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