BIOL 198 Module 7 Objectives

BIOL 198 Module 7 Objectives Questions And Actual Answers Define homeostasis, negative feedback, and positive feedback, and be able to describe the relationship of both feedback mechanisms to homeostasis. - Homeostasis: Maintenance of constant internal conditions. Negative feedback: A change in one direction initiates an opposite response, meant for snuffing excesses. Positive feedback: Change in one direction initiates an identical response, increasing the magnitude of the stimulus. Not seen in homeostatic processes. Define immunity, and describe the differences between the adaptive (specific) and innate (non-specific) defense mechanisms that contribute to immunity. - Immunity is the ability of the body to defend itself from foreign cells or viruses, as well as abnormal body cells. The former type is non-specific series of barriers that block/hamper all foreign bodies that attempt to enter the body. The latter defends against specific things to which the body has been previously exposed. Define incomplete and complete digestive systems, and identify the overall tasks of a complete digestive system. - Incomplete: One opening, simple Complete: Two openings (one for intake and one for waste excretion), complex The four taks of a complete digestive system include: Ingestion, Digestion, Absorption, and Elimination. Define neurotransmitter and hormone, how these molecules influence mammalian organs and tissues, and where the receptors for these molecules are located. - Hormone: A signaling molecule released by one cell that acts on other target cells. They are divided into two distinct classes: lipid (primarily steroids in humans) and peptide. They both travel through the bloodstream to reach their target cells. Steroid hormones diffuse through the plasma membrane to bind to intracellular receptors. This allows for the regulation of the mRNA synthesis of specific genes Peptide hormones binds to surface receptors. A signaling pathway triggers to bring about the effect associated with the hormone. Neurtoransmitter: a chemical agent that can regulate neurons, muscle cells, and endocrine cells. They bind to ligand-gated ion channels in the postsynaptic neuronal plasma membrane, causing an excitatory or inhibitory effect. Neurotransmitters are then either diffused out, degraded by enzymes, or recycled by the presynaptic neuron. Define segmentation and cephalization, and identify the advantages of these features. - Segmentation: body divided into repeating subunits. Advantages include increased flexibility and mobility, potential for regeneration Cephalization: Describes the development of a structure at one end of the body that has specialized feeding and sensory structures. This is advantageous because it allows for the gathering and processing of sensory information, as well as the rapid consumption of located food. Define the different types of body cavities and identify the advantages that animals with body cavities have compared to animals without body cavities. - Acoelomate: No cavity. The areas between the ectoderm and endoderm is filled with cells made of mesoderm. Pseudocoelomate: A fluid-filled cavity is present, but only the outside is lined with mesoderm and organs are not completely anchored. Eucoelomate: A more complex fluid-filled cavity with mesoderm lining all internal organs and structures. Tissues derived from mesoderm also anchor organs in place. Advantages that a eucoleomate has over a pseudo- or acoleomate include but are not limited to: Organs are anchored in place and protected Organs can become more specialized and complex. Independent movement of internal organs and body wall is possible. Internal fluid can protect the internal environment and aid in movement of materials. Enables function as a hydrostatic skeleton. Define tissues, organs, and organ systems, understand the relationships between them and the life processes associated with each organ system. - Tissue: An organized assemblage of similar cells which have a similar function, such as nervous tissue Organ: Multiple tissues working toward a larger goal. Organ system: Made up of multiple organs that function together. Define vitamins and minerals, learn the different types, and why they are important for maintaining homeostasis. - Vitamins and minerals are required by living organisms and must be obtained from the diet Vitamins are organic, minerals are not. Too few of either of these can cause disease Too much can also lead to disorders Vitamins are either water- (B viatmins, C) or fat-soluble (A, D, E, K). Minerals can be macro- (Ca, Cl, Mg, P, K, Na) or micronutrients (Cu, I, Fe, Mn, Mo, Se, Zn). Describe antibodies (as the humoral response of adaptive immunity), where they are produced and how they function. - Antibodies are any substance produced by B-lymphocytes that bind to recognized antigens. Once an antibody binds to an antigen, it can interfere with viral or bacterial processes. It can affect their ability to spread and/or mark them for destruction by a phagocyte. Describe how analysis of urine components can be used to gather information about normal and abnormal physiology. - If proteins are in the urine, the glomerulus is failing to separate small molecules from larger molecules. If glucose is in the urine, the proximal convoluted tubule is failing to reabsorb the glucose. If a pregnancy is able to be determined by urinalysis, then the distal convoluted tubule is functioning normally (hormones are not recovered by the body, and are excreted as waste). Describe how signals are conducted along axons (action potential) and between nerves (synaptic transmission), and understand the feedback mechanisms involved in signal conduction by the nervous system. - 1. Depolarization toward threshold potential 2. If threshold of excitation is reached, all Na+ channels open and the membrane depolarizes 3. At the peak action potential, K+ channels open and K+ leaves the cell. Na+ channels close. 4. The membrane becomes hyperpolarized as K+ ions continue to leave the cell. During this period, it cannot fire again. 5. K+ channels close, resting potential restored by Na/K pumps Positive feedback comes from the slight depolarization leading to a great depolarization. Negative feedback comes from removing neurotransmitters from the synaptic cleft to halt signal propagation. Describe immunological memory and understand how vaccines function. - As B and T cells mature into effector cells, some form into memory cells that circulate for years. These cells can differentiate into plasma cells and cytotoxic T cells without input from APCs or helper T cells. This causes a secondary immune response. Vaccines provoke a primary immune response, which sparks the creation of memory cells for the (greater in magnitude) secondary immune response. Describe open and closed circulatory systems and explain the advantages and disadvantages of each type. - Open circulatory systems are less complex and require less energy. Closed circulatory systems are more efficient and contain all blood in vessels, resulting in higher blood pressure. Describe the basic functional unit of muscle contraction and identify the structures found within this unit. - The sarcomere. Sarcolemma: Plasma membrane of a muscle fiber Myofibril: many continuous sarcomeres, long cylindrical structures that cause the mu