BSC 109 1nd EditionExam # 3 Study Guide Lectures: 14 - 18Lecture 14 Describe the first two lines of defense in the lymphatic system, its components, and what each one does.Keeping pathogens out: the first line of defense includes: Skin: most important barrier from pathogens, Structure is dead, Constantly renewed, Acidic pH of 5-6, Antibiotic production. Tears and saliva contain lysozyme (antibacterial enzyme). Ear wax: entraps microorganisms. Mucus entraps microorganisms, Thick,gel-like substance. Cilia in throat (ruined in smokers -> smoker’s cough), Sneezing. Stomach is highly acidic. Vagina is slightly acidic, inhibits some microorganisms. Vomiting, urination, and defecation remove microorganisms. Resident bacteria outcompete pathogens.Nonspecific defenses: Second line of defenseNOT specific for any particular pathogen. Phagocytic cells are white blood cells that surround and engulf invading bacteria. They include Neutrophils, which digest and destroy bacteria or fungi, Eosinophil, which, when foreign cells are large, form clusters and use enzymes to destroy foreign cells, and Macrophages, which phagocytes derived from monocytes that engulf debris and foreign cells. Inflammation is redness (extra blood supply), warmth (from extra blood), swelling, and pain- NOT bad. Natural killer cells are a type of lymphocyte that attacks tumor cells and virus-infected cells, Interferon are antiviral proteins. The fever response includes bodies fighting off infection, which Makes the body a hostile environment for bacteria but beneficial for metabolic defense processesLecture 15 Describe the components and processes of the lower respiratory tract.The Larynx includes the epiglottis, which is a flexible flap of cartilage that routes air and food appropriately, the Vocal cords, which assist in sound production and it maintains open airway. The Trachea is kept open by C-shaped rings of cartilage and is lined with mucus-secreting ciliated epithelium. It also induces the cough reflex.The bronchi includes the trachea, which branches into two airways- right and left bronchi. It alsocontains ciliated epithelia, smooth muscle, cartilage, and bronchioles, which are smaller branches, lack cartilage. The bronchi and bronchioles function to clean, warm, and humidify incoming air.Lecture 16Describe the two main parts of the nervous system, their components and what they do. Central nervous system includes the brain and spinal cord. It receives, processes, and transfers information.Peripheral nervous system includes nerves outside CNS. It involves sensory division to carry information toward the CNS and motor division to carry information away from CNS; somatic and autonomic divisions.Lecture 17Describe the ways sensory neurons provide information to the CNS.It provides information for both the somatic and autonomic motor divisions of the PNS. The somatic division controls skeletal muscles, while the autonomic division controls automatic body functions. It includes the sympathetic system, which prepares the body for emergency, and the parasympathetic system, which relaxes the body. It is part of the motor output of the PNS, which controls automatic body functions and permits defecation and urination.The brain and spinal cord constitute the CNS. They are composed of bone, meninges, cerebrospinal fluid, and a blood-brain barrier. The spinal cord relays information. The brain processes and acts on information.Lecture 18Describe how CNS interprets nerve impulses based on origin and frequency.Nerve impulses are transmitted from receptors to specific portions of brain.A. Stronger stimuli activate a greater number of receptors and trigger a greater frequency of action potentials in sensory neurons. Some receptors adapt to continuing stimuli. Sensory adaptation occurs when sensor neuron stops sending impulses even though the original stimulus is still present. It allows the CNS to concentrate on important stimuli and ignore noncritical ones to maintain homeostasis. Receptors that adapt include light touch, pressure, smell. Receptors that do not adapt are pain, joint, and muscle monitoring receptors. Somatic sensations and special senses provide sensoryinformation including somatic sensations, which arise from receptors located throughoutthe body, including temperature, pressure, touch, vibration, pain, awareness of body positions. Special senses arise from receptors restricted to specific areas of the body, including taste, smell, hearing, balance, and