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Exam #3 W 4/7 in class Review T 4/6 at 6-8pm in SZB 104 Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Fig 48.3 Response Responses can be release of hormones, change in cell activity, or muscle contraction Muscles can only contract. Therefore, two muscles are needed for each range of motion. Fig 50.32 2 nerve signals for every movement: excitatory and inhibitory Fig 50.32 How do muscles contract? Excitatory neurotransmitters released by motor neurons cause muscle cells to contract Fig 50.29 Muscle cells are comprised of series of sarcomeres. Fig 50.25 Fig 50.25 Each sarcomere is a repeating unit of actin and myosin proteins Fig 50.25 As each sarcomere contracts, the muscle cell contracts Neurotransmitters released at nerve/ muscle junction cause calcium to be released in muscle Fig 50.29 Fig 50.28 A third protein, tropomyosin controls when the muscle contracts Fig 50.27 ATP provides the energy for myosin movement along the actin The contraction of muscle cells causes the muscle to contract Taking in food and oxygen exposes us to pathogens esophagus stomach Pathogen: a disease causing agent E. coli Phage virus Ebola Fungus from soil various pathogens The Immune System • Non-specific: – barriers • Specific: –B-cells -> antibodies –T-cells Fig 43.2 Non-Specific Immune System Barriers: SkinDry Inhospitable Competition Secretions (lysozyme) Hairs and Mucus (protect openings) Traps particles, swallowed Stomach acid kills pathogens Fig 43.2 Skin protects us from most pathogens Fig 43.2 Hairs and Mucus (protect openings) Traps particles Stomach acid kills pathogens esophagus stomach Non-Specific Immune System Barriers: SkinDry Inhospitable Competition Secretions (lysozyme) Hairs and Mucus (protect openings) Traps particles, swallowed Stomach acid kills pathogens Fig 43.2 The Immune System • Non-specific: – barriers • Specific: –B-cells -> antibodies –T-cells Fig 43.2 The Specific Immune System B-cells and T-cells move through the circulatory system scanning for pathogens B-cells develop in bone marrow T-cells in the thymus B-cells make and secrete antibodies Fig 43.14 Variable region An Antibody Constant region Fig 43.10 Antibodies recognize and bind to antigens Fig 43.10 B-cells male antibodies that bind to antigens marking them for destruction Fig 43.19 Marked for destruction by WBC Each B-cell/antibody recognizes a specific antigen Fig 43.14 B-cell DNA rearranges to make a unique and random gene Fig 43.13 Specific Immune System Overview Fig 43.16 Exam #3 W 4/7 in class Review T 4/6 at 6-8pm in SZB 104