Assessment 5 - Bio 10B PDF
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Pasadena City College
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This document covers the immune system, focusing on inflammatory responses and systemic chronic inflammation. It also explores the relationship between stress and the immune system, and the role of microbial dysbiosis in inflammation. The document includes details on muscle contraction and related physiological effects too.
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Assessment 5 The immune system The inflammatory response The process ○ Bacteria and other pathogens enter wound ○ Platelets from blood release blood-clotting proteins at wound site ○ Mast cells secrete factors that me...
Assessment 5 The immune system The inflammatory response The process ○ Bacteria and other pathogens enter wound ○ Platelets from blood release blood-clotting proteins at wound site ○ Mast cells secrete factors that mediate vasodilation and vascular constriction Production of major acute innate cytokines involved in local and systemic responses following leukocyte activation via TLRs or danger-associated molecular pattern receptors Homeostasis of the inflammatory response Systemic chronic inflammation ○ Causes almost all diseases Depression, cancer, aging, etc The physiological effects of stress on the immune system Homeostasis and the immune response ○ hypothalamo-pituitary-adrenocortical(HPA) axis Regulates homeostasis of the immune response ○ Communication between the nervous system and immune system is bi-directional, with both systems releasing chemical signals to instruct the other system’s actions ○ When infection occurs: immune system releases cytokines to initiate an attack, but it needs to be turned off to prevent damage to healthy tissues ○ Stress can trigger the release of glucocorticoids, depressing the immune system in the short term ○ If stress persists, immune cells become resistant to glucocorticoids, leading to immune dysfunction and potential health issues ○ Variability in the stress response depends on individual factors such as developmental experiences, current circumstances, and personality. ○ Chronic stress can have cumulative effects that impact the aging process and promote disease. ○ Systemic Chronic Inflammation and the Etiology of Disease Systemic chronic inflammation (SCI) refers to a prolonged and low-grade inflammatory response that can lead to various diseases Factors such as: ○ social, psychological, environmental, and biological elements contribute to the development of SCI In response to inflammation, the body undergoes metabolic and neuroendocrine changes to conserve energy and support the immune system These changes manifest as behavioral symptoms known as “sickness behaviors,” including fatigue, reduced libido, altered sleep, and social withdrawal. SCI can lead to immune dysfunction, increased susceptibility to infections and tumors, and poor vaccine response It can also have developmental consequences during pregnancy and childhood, elevating the risk of non-communicable diseases throughout life. Microbial dysbiosis, characterized by imbalances in the gut microbiota, is associated with SCI and various diseases. Mechanisms linking gut microbiota and inflammation include the presence of: ○ immune-stimulatory lipopolysaccharides (LPS) Disruption and dislocation can lead to: leakiness and dysregulated permeability of the gut means macrophages can infiltrate the region, produce and activate inflammatory cytokines, leading to local inflammation. ○ the role of short-chain fatty acids in modulating inflammatory cascades In many animal studies, SCFA butyrate has been associated with a variety of roles that oppose the onset of metabolic disorders ○ the influence of cytokines on immunomodulation anti-diabetic effects ○ the production of trimethylamine N-oxide(TMAO) from dietary compounds linked with deleterious effects including endothelial dysfunction, which in turn promotes vascular inflammation, atherosclerosis and other cardiovascular disease risk factors. How a muscle contracts skeletal and cardiac muscle is made up of muscle fibers ○ These are composed of myofibrils or muscle cells contractile unit of a myofibril is called a sarcomere Myofibrils are composed of long proteins including actin, myosin, and other proteins that hold them together. Because actin is attached to the Z-line, it pulls the Z-lines closer together when myosin binds to it and slides it ○ this is a contraction Anatomical evidence for bipedalism Cranium ○ placement of the foramen magnum, the large hole on the cranium through which the spinal column passes ○ In a quadruped, the spinal column also runs parallel to the ground so the foramen magnum is more dorsally placed (i.e., toward the back of the cranium). ○ In a bidped, the spinal column runs perpendicular to the mandible and the ground. Lumbar vertebra ○ In most quadrupedal hominins, the center of gravity is located near center on the torso ○ In modern humans, the center of gravity is closer to the center of the pelvis. Endurance running in humans Since human bodies are virtually hairless, we dissipate heat via evaporative cooling (sweat) through our skin and because our bodies are upright, our organs do not pound our lungs while we run so we get adequate oxygen as we run. Endurance hunters, although slower, can catch prey because of their ability to endure long distance running relative to their prey. When their prey stop to cool down, they are vulnerable to attack. Human runners reduce these stresses to some extent byexpanding joint surfacesand spreading forces over larger areas. ○ Homo has substantially larger articular surface areas relative to body mass in most joints of the lower body, including the femoral head and knee, the sacroiliac joint, and the lumbar centra. Trunk stabilization is achieved byexpanding areas on the sacrumand the posterior iliac spinefor the attachment of the large erector spinae muscles, and a greatly enlarged gluteus maximus. Humans are capable of a substantiallygreater degree of isolated rotation of the trunk relative to the hipscompared to apesdue to a narrow waistthat vertically separates the lower margin of the thorax from the pelvis. Match each of the characteristics with the muscle fiber it describes. Contain mitochondria to generate ATP using oxygen efficiently. ○ Slow twitch fibers Quick to fatigue. ○ Fast twitch fibers Not able to generate a significant amount of force. ○ Slow twitch fibers Have a high threshold and will be recruited or activated only when the force demands it. ○ Fast twitch fibers Immune System Knowledge Quiz Which of the following is not part of innate immunity? ○ antibodies dendritic cell ○ Presents antigens on its surface, triggering adaptive immunity. mast cell ○ Dilates bloom vessels and induces inflammation through the release of histamines and heparin. natural killer cells ○ Kills tumor cells and virus infected cells. Macrophage ○ P hagocytic cell that consumes foreign pathogens and cancer cells. Recruits other cells to the site of the infection. Lymphocytes that originate in the bone marrow mature into ○ B cells Lymphocytes that migrate from bone marrow to the thymus mature into ○ T cells Proteins produced by plasma cells after stimulation by an antigen; they are the functional basis of humoral immunity. ○ antibodies
