BPK 105 FINAL EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

BPK 105 FINAL EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 Briefly describe the functions of the digestive system - Answers Ingestion - Consumption through the mouth in solid or liquid form Digestion - Breakdown of large organic molecules into smaller absorbable molecules Absorption - Movement of molecules out of the digestive tract and into the blood or lymphatic system Elimination - Removal of undigested material through feces Describe the structure and general functional roles of the four tunics (layers) of the digestive tract and briefly highlight the differences between the different organs related to their specialized functions - Answers The four tunics include: - Muscosa Consists of the muscosa epithelium, lamina propria, muscularis mucosae - Submucosa Thick layer of connective tissue that contains nerves, vessels and glands - Muscularis Inner layer of smooth muscle and outer layer of longitudinal smooth muscle - Serosa (Adventitia) Smooth epethelial layer with connective tissue Name and describe the three phases of deglutition (swallowing). Include the relevant anatomy involved in each phase - Answers Divided into: - Voluntary phase Bolus or mass is formed in the mouth with the tongue pushing it towards the hard palate and into the oropharynx - Pharyngeal phase Soft palate elevates to block the nasopharynx keeping the larynx and pharynx elevated. Epiglottis is pushed down over the larynx. Bolus is pushed into the esophagus. - Esophageal phase Peristaltic contractions move the bolus down the esophagus towards the stomach Describe the cephalic phase of stomach secretion. Include the function, stimulation for release and gland of origin of each secretion. - Answers Smells of food and relevant thoughts trigger the medulla oblongata to influence gastric secretions. The enteric plexus becomes stimulated by preganglionic neurons which stimulates secretory cells in the stomach to release: Hydrochloric acid Mucus Intrinsic factor Gastrin Histamine All released by parietal and chief cells Describe the intestinal phase of stomach secretion. Describe the hormones and pathways involved in modifying gastric activity - Answers Inhibits gastric secretions and is controlled by the entrance of acidic chyme into the duodenum When pH of chyme drops below 2.0 the inhibitory effect of the intestinal phase is greatest With low pH the hormone secretin is released to stop gastric secretions. Fatty acids and peptides release cholecystokinin also inhibiting gastric secretions. Negative feedback loop that raises pH Compare and contrast the structure of the mucosal layers of the stomach and small intestine. What does this tell you about the roles of the stomach and small intestine within the digestive system? Provide a brief description of two specialized structures from each organ's mucosal layer to support your discussion of its role. - Answers Surface mucosal cells of the stomach: Inner surface of the stomach and lining of the gastric pits Produce mucous Chief cells of the stomach: secrete pepsinogen which is a precursor for pepsin Mucosa cells of the small intestine: Absorptive cells that produce digestive enzymes and absorb digested food. Epithelial cells of the Small intestine: Secretes peptidases and disaccharidases The Small intestine and stomach play a key role in digesting foods to their most basic components and preparing them for more extensive absorption Describe the control of release and function of each of the secretions from the exocrine pancreas. - Answers Bicarbonate Ions: - Neutralize chyme from the stomach and allows pancreatic enzymes to function - Released by the presence of chyme in the duodenum Proteolytic Enzymes: - Includes trypsin, chymotrypsin and carboxypeptidase and all continue protein digestion started in the stomach - Release triggered by cholecystokinin Pancreatic Amylase: - Continues polysaccharide digestion - Release triggered by cholecystokinin Lipase: - Digests lipids - Release triggered by cholecystokinin Nuclease: - Degrades DNA and RNA to nucleotides - Release triggered by cholecystokinin Parasympathetic stimulation causes further stimulation through the vagus nerve leading to more pancreatic enzyme release Distinguish between the processes of digestion and absorption through definition and description. Where in the gastrointestinal system do they generally take place? - Answers Absorption: The taking in or movement of molecules in the digestive tract through the intestinal wall and into the bloodstream. Most absorption occurs in the duodenum and jejunum; potentially the ileum Digestion: Breakdown of carbs, lipids and proteins into their basic component to prepare for absorption. Occurs in the oral cavity, stomach, small intestine, large intestine; implicates the salivary glands, liver and pancreas. Describe the digestion and absorption of carbohydrates through the entire digestive system. Include the site, stimulation and function of important secretions and describe the details of absorption across the cell membrane. - Answers Mouth: Salivary amylase released by salivary glands commences carbohydrate digestion breaking them down into disaccharides and polysaccharides Stomach: Mixes with acid to inactivate salivary amylase Duodenum: Pancreatic amylase continues the digestion that commenced in the mouth and breaks down polysaccharides into disaccharides. Disaccharidases break down the disaccharides into monosaccharides for absorption to begin Glucose, galactose and fructose are absorbed through intestinal epithelial cells. Galactose and glucose are absorbed with co-transport that uses the Na+ concentration gradient. Fructose is transported through facilitated diffusion. Describe the digestion and absorption of lipids through the entire digestive system. Include a detailed description of the roles of the liver and the process of emulsification. Describe the process of lipid absorption and transport. - Answers Duodenum: Ingested lipids are digested by lipase and emulsification Lipase produces monoglycerides and fatty acids Emulsification is the process of bile salts transforming larger fat globules into smaller digestible segments. Bile salts mix with lipids disrupting the droplets and surround them promoting the effect of lipase Micelles are formed from the aforementioned process and are transported through the intestinal epithelial cells and are converted to chylomicrons Chylomicrons enter the lacteals in the intestinal villi and begin transport to the liver Upon arrival, the liver can store them, convert them into other molecules or use them as energy. Describe the digestion and absorption of proteins through the entire digestive system. Include the site, stimulation and function of important secretions and describe the details of absorption across the cell membrane. - Answers Protein digestion commences in the stomach with the action of pepsin which is converted from pepsinogen by HCl. This converts proteins into polypeptides. Once passed through the stomach, pancreatic enzymes; trypsin, chymotrypsin and carboxypeptidase continue digestion. Polypeptides then become tripeptides, dipeptides and amino acids due to peptidases in the SI located on the microvilli. Tripeptides, dipeptides and amino acids are transported through intestinal epithelial cells through cotransport with Na+. Tripeptides and dipeptides are broken down into amino acids inside the epithelial cells. Approximately 9 L of water enter the digestive tract daily. Where does this water come from, where does it end up, what regulates its movement and what are its functions - Answers 2L of water is ingested through food and drink, 7L from digestive secretions 92% absorbed in SI, 7% in the large intestine and 1% leaves in feces Osmosis causes movement of water in the intestines, bidirectional movement. Determined by osmotic gradients of the epithelium. Diluted chyme causes water to move into the blood whereas concentrated chyme leads to water entering from the blood to the SI Water is important for: Stabilizing body temperature Providing protection Facilitating chemical reactions Transporting substances Describe the functions of the respiratory system - Answers Main function: Respiration which includes the movement of air into and out of the lungs, exchange of CO2 and O2, transport of CO2 and O2 in the blood and exchange O2 and CO2 in tissues Regulation of blood pH by changing CO2 levels Voice production through air passing the vocal cords Olfaction from drawing airborne molecules into the nasal cavity Innate immunity by removing pathogens from respiratory surfaces Describe the pressure changes involved during inspiration and expiration include the changes in thoracic volume and specific muscle contractions during one breathing cycle at rest and during exercise - Answers During inspiration, alveolar pressure drops below atmospheric pressure due to the contraction of diaphragm inferiorly and intercostals pushing the ribcage upwards causing thoracic volume to increase. During expiration alveolar pressure is higher than atmospheric pressure and intercostals and diaphragm relax to reduce the thoracic volume and let air be expired. During labored breathing the thoracic cavity volume increases greatly and all the inspiratory muscles are active and they contract more forcefully. These muscles include abdominals and intercostals. Describe surfactant and pleural pressure including their roles of in preventing the collapse of alveoli. Briefly describe infant respiratory disease syndrome (IRDS) in premature infants and why it is critical to treat it effectively. - Answers Surfactant is a lipoprotein mixture that prevents alveoli from recoiling with enough force to cause collapse by reducing surface tension. Pleural pressure is less than alveolar pressure causing the alveoli to expand, this is caused by a suction effect from the lymphatic system removing fluid and lung recoil. IRDS is caused by too little surfactant in a premature infant. This is important to treat to prevent lung collapse so an expecting mother may be given cortisol which increases surfactant synthesis in the fetus. Describe gas exchange in the pulmonary and systemic circulatory systems for oxygen and carbon dioxide. Include the changes in partial pressures for both of these dissolved gases and the driving force for exchange at each location. What impact would pulmonary edema, an increase in interstitial fluid in the lungs, have on gas exchange? List the other factors could influence the rate of gas exchange at the respiratory membrane? - Answers O2 diffuses through the respiratory membranes 20 times less easily than does CO2 Oxygen diffuses from the alveoli into the pulmonary capillaries because the Po2 in the alveoli is greater than the capillaries. CO2 diffuses from the pulmonary capillaries into the alveoli because Pco2 is greater in the capillaries than in the alveoli Edema causes there to be a thicker than normal layer of fluid for the gases to diffuse across. This causes the rate of gas exchange to markedly decrease, this affects oxygen before CO2 due to their differences in diffusion. Describe the transport of oxygen in circulation. What environmental changes occur as blood enters active muscle influence the release of oxygen from hemoglobin? How does the release of oxygen differ during exercise? - Answers 98.5% of oxygen is carried in the blood through the heme group of oxyhemoglobin. At high Po2 hemoglobin binds to O2 and at low Po2 it releases O2. This causes O2 to be released into the tissues. The amount of O2 released from oxyhemoglobin depends on low Po2, high Pco2, low pH and high temperature. When exercising the Po2 is lower and Pco2 is higher as well as low pH and high temperature this causes as much as 73% of the O2 picked up in the lungs by hemoglobin to be released into tissues Describe the various ways carbon dioxide is transported in circulation, including the approximate percentage that is transported in each way include the full reaction catalyzed by carbonic anhydrase. How does this equilibrium reaction change between the tissues and the lungs - Answers Carbon dioxide is transported through the blood through dissolved CO2 in the plasma, bound to blood proteins and in the form of bicarbonate ions. Approximately 7% is transported through the plasma, 23% in blood proteins and 70% in bicarbonate ions. The enzyme carbonic anhydrase within RBC's helps to catalyze the reaction in which bicarbonate ions are formed. Carbonic anhydrase speeds up the reaction producing bicarbonate ions by increasing the reactivity between CO2 and water. When the reaction is in the region of the lungs, the reaction becomes reversed and HCO3 combines with H+ leading to the expiration of CO2. CO2+H2O - H2CO3 - H+HCO3 Describe the rhythmic control of ventilation. Describe the phases of change in ventilation during exercise. How does exercise training affect ventilation at rest and during exercise? - Answers Starting inspiration occurs with neurons in the medullary respiratory center that promote inspiration and are always active. Stimulation from muscles, pH and other areas reach a threshold level and the somatic nervous system stimulates the respiratory muscles via action potentials. Increasing inspiration occurs with a progressively stronger stimulation of the respiratory muscles that lasts for approx. 2 seconds. Stopping inspiration occurs when muscles of respiration stimulate neurons in the medullary respiration center for stopping inspiration. Inhibits neurons stimulating the respiratory muscles, causing relaxation of respiratory muscles resulting in expiration which lasts approx 3s Exercise increases breathing abruptly and gradually. Abruptly occurs with as high as 50% higher increases in breathing due to action potentials in collateral fibers which stimulate the respiratory center, body movements stimulate proprioceptors in the joints and limbs which connect to the respiratory center and also increase breathing. Potentially a learning component. Gradual increases occur probably due to the same causes of abrupt increases. Describe the chemical control of ventilation. When are blood oxygen levels important? Describe the step-by-step response to an increase in Carbon Dioxide in the blood. - Answers Levels of CO2 in the blood are the main driving force for regulating breathing Chemoreceptors in the medulla are sensitive to pH levels (increased hydrogen ions) and stimulate breathing If CO2 levels are high pH decreases and H+ levels increase. Chemoreceptors in the medulla oblongata will increase breathing. The increase in breathing will increase the amount of CO2 diffusing out of the body causing pH to increase. Oxygen chemoreceptors are located in the carotid and aortic bodies. These are primarily stimulated during altitude change, shock, emphysema and asphyxiation. Upon stimulation increase breathing by sending action potentials to the medulla. Describe the process by which more red blood cells are made in response to low oxygen. What nutrients are required for this process, Why? - Answers When blood oxygen levels become low, blood CO2 levels increase. This causes the production of glycoprotein erythropoetin. This glycoprotein causes red bone marrow to produce more RBC's. This makes it a part of a negative feedback loop where the increase in RBC's causes more oxygen to be transported and homeostasis to be maintained. Describe the functions of the heart, including the heart structure responsible for each function - Answers The heart generates blood pressure