exam 4 Flashcards
why do cells need to communicate
coordinate function, development, and responses to the environment, orchestrated through chemical messengers - hormones that act on receiver target cells, target cells respond
what is an endocrine system
hormones are released in one place and target cells
control systems
gather feedback on how the process is going, responses can be stimulating or inhibiting
feed-forward regulation:
a master signal hormone stimulates the production of target hormones by other endocrine organs
feedback loops need
must have some sort of negative feedback loop because we don’t want it to be on all the time: fewer things produced, inhibiting signal from start
integrated systems communicate what
which tissues should grow and when
integrated systems communicate when
adequate nutrition for growth signals, growth hormone-releasing hormone (GHRH), GH binds to receptors on target cells, causing them to divide, GH stimulates the production of IGF-1, a hormone that stimulates uptake of amino acids, somatostatin, gherkin increases food intake, all organisms have growth hormones, no growth hormone products don’t exist
integrated systems normal metabolism
communicate energy storage status, energy usage, energy needs, communicate all the time
integrated systems metabolism during stress
glucose needed rapidly, during a stress response
integrated systems sexual phenotype
multivariate; morphological traits: gonads, genitals, ornamentation, body size, reproductive states: estrous cycling and gametogenesis, behavior: courtship displays, mating receptivity, aggression, parental care
host-parasite co-evolution
hosts are better at resisting infection.clearing parasites, parasites are better at exploiting host and evading clearance produce more offspring, both have evolutionary constraints and may face many trade offs
host-parasite immune defenses
evolved to be more complex with the complexity of multicellular life, highly redundant multilevel network at work in ever cell, detect, resist, remove, and tolerate danger, communicate health and disease signal with many other physiological systems
three levels of immune defense
- physical barriers: skin and mucosa
- innate immunity: non-specific immunity present from birth
- adaptive immunity: specific immunity learned after contact with a pathogen
immune cells and tissues
bone marrow is site of hematopoiesis, innate: cells that reside in tissue and blood - surveillance crew, adaptive: lymphocytes mostly reside in lymphoid tissue, specialized forces called in after danger is identified
innate immune response: recognize danger
some pathogens breach skin and mucosal barrier, specific proteins and receptors recognize common patterns on microbial surfaces and bind to them, innate cells in tissue at site of infection: secrete peptides that destroy microbes through membrane destabilization, engulf through phagocytosis, induce inflammation
innate immune response: inflammation
occurs when innate immune cells recognize infection and release inflammatory cytokines, increased fluid at the site of infection, fever, cells that phagocytized antigens migrate to lymphoid tissue to activate adaptive immune response
adaptive immune response
first antigen encounter causes first adaptive immune response, B cells produce antibody if they recognize the pathogen, some t cells can directly kill cells infected with intracellular pathogens, some activated B cells become memory cells: long-lived cells capable of activation if exposed to same pathogen, secondary exposure reactivates memory cells, resulting in a stronger and faster immune response
immune system malfunctions
hypersensitivity reactions, autoimmune diseases, cancer
hypersensitivity reactions
allergies: recognition of a foreign but not innocuous material, activate granulocytes, induce localized symptoms, can be severe/deadly (anaphylaxis), some are genetic, most are environmental
autoimmune dieases
B cells and T cells that recognize self-molecules as danger enter circulatory and lymphatic systems, adaptive immune response to tissues within the body, can cause inflammation at recognition sites or destruction of the tissue
cancer
individuals acquire random mutations in genes over a lifetime, some mutations occur in genes controlling
eco immunology
hoe ecology affects immunity and vice versa
tenets of eco immunology
immune responses are dependent on intrinsic and extrinsic factors and prior experiences, immune maintenance and mounting an immune response are energetically demanding processes, individual immunity can affect ecological interaction and processes
benefits of parasitism
ready access to nutrition from host, free transport to other areas, shelter from adverse environmental conditions and predation
