Physiology exam prep 2
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Questions and Answers

What is the primary function of the hormone produced by the α cells in the pancreatic islets?

  • To decrease glucose levels in the blood
  • To regulate gastrointestinal movement
  • To stimulate the release of insulin
  • To increase glucose levels in the blood (correct)

    • What is the target organ of the hormones produced by the pancreatic islets?

  • Duodenum
  • Adrenal glands
  • Liver (correct)
  • Pancreas

    • What is the effect of insulin on the permeability of the cell membrane to glucose?

  • It decreases the permeability
  • It depends on the dosage of insulin
  • It increases the permeability (correct)
  • It has no effect on permeability

    • What is the result of injecting a small amount of insulin into the body?

    <p>Blood glucose level decreases</p> Signup and view all the answers

    What is the consequence of a lack of insulin in the body?

    <p>Blood glucose level increases</p> Signup and view all the answers

    What is the term for the excretion of glucose in the urine?

    <p>Glycosuria</p> Signup and view all the answers

    What is the effect of hyperglycemia on the body's water balance?

    <p>It decreases the reabsorption of water in the nephron tubules</p> Signup and view all the answers

    What is the result of the accumulation of ketones in the body?

    <p>The pH of the blood becomes acidic</p> Signup and view all the answers

    What is the consequence of severe acidosis in the body?

    <p>Diabetic coma and death</p> Signup and view all the answers

    What is the term for the lack of oxygen in tissues?

    <p>Hypoxia</p> Signup and view all the answers

    What is the duration of the cardiac cycle in horses?

    <p>1.4 sec</p> Signup and view all the answers

    How much of ventricular filling occurs during the mid-to-late diastole phase?

    <p>70-80%</p> Signup and view all the answers

    What valves are open during the ventricular filling phase?

    <p>Tricuspid and mitral valves</p> Signup and view all the answers

    What is the primary function of atrial contraction?

    <p>To pump blood into the ventricles</p> Signup and view all the answers

    What is the duration of atrial systole in humans?

    <p>0.1 sec</p> Signup and view all the answers

    During atrial systole, blood is pumped into the ventricles through which valves?

    <p>Tricuspid and mitral valves</p> Signup and view all the answers

    What is the duration of ventricular systole?

    <p>0.3 sec</p> Signup and view all the answers

    Which phase of the cardiac cycle is characterized by the relaxation of the atria and ventricles?

    <p>Total diastole or pause</p> Signup and view all the answers

    During the ventricular filling phase, blood flows into the right atrium from which vessels?

    <p>All of the above</p> Signup and view all the answers

    What is the duration of the total diastole or pause phase in the cardiac cycle?

    <p>0.4 sec</p> Signup and view all the answers

    What is the primary reason for the closure of the tricuspid and mitral valves during isovolumetric contraction?

    <p>Blood flows back toward the atria, causing the valves to close.</p> Signup and view all the answers

    During which phase of the cardiac cycle does the pressure in the ventricles drop below the pressure in the pulmonary trunk and aorta?

    <p>Early diastole</p> Signup and view all the answers

    What is the main difference between the pressure generated by the left and right ventricles during the ventricular ejection phase?

    <p>The left ventricle generates a higher pressure due to the higher pressure in the aorta.</p> Signup and view all the answers

    What occurs during the late diastole phase of the cardiac cycle?

    <p>Blood flows from the atria into the ventricles, pushing open the tricuspid and mitral valves.</p> Signup and view all the answers

    What is the primary mechanism responsible for the relaxation of the respiratory muscles during expiration?

    <p>The relaxation of the respiratory muscles due to the elastic recoil of the lungs.</p> Signup and view all the answers

    What occurs during the passive expiration process?

    <p>Impulses through the afferent parasympathetic n.vagus fibers go to the respiratory center, suppressing the inspiratory neurons.</p> Signup and view all the answers

    What is the role of the pons in the brain during the transition from inspiration to expiration?

    <p>It switches from inspiration to expiration, sending information to the spinal cord.</p> Signup and view all the answers

    What is the result of the pressure in the lungs becoming higher than atmospheric pressure during expiration?

    <p>Air flows out of the lungs.</p> Signup and view all the answers

    During which phase of the cardiac cycle do the atrioventricular valves remain closed, and the semilunar valves remain open?

    <p>Ventricular ejection phase</p> Signup and view all the answers

    What is the primary factor that determines the volume of blood in the ventricles during the isovolumetric contraction phase?

    <p>The volume of blood remains constant.</p> Signup and view all the answers

    What is the primary cause of ischemic hypoxia?

    <p>Impaired blood supply to tissues</p> Signup and view all the answers

    What is the effect of sympathetic nervous system stimulation on kidney blood vessels?

    <p>Vasoconstriction</p> Signup and view all the answers

    What is the result of increased parasympathetic activity on glomerular filtration rate?

    <p>Increased filtration rate</p> Signup and view all the answers

    Which of the following is an example of histotoxic hypoxia?

    <p>Carbon monoxide poisoning</p> Signup and view all the answers

    What is the effect of pain on the release of antidiuretic hormone (ADH)?

    <p>Increased release of ADH</p> Signup and view all the answers

    What is the result of increased blood supply to the kidneys on diuresis?

    <p>Increased diuresis</p> Signup and view all the answers

    What is the primary regulator of glomerular filtration rate?

    <p>Neural regulation</p> Signup and view all the answers

    What is the effect of sympathetic nervous system stimulation on filtration processes?

    <p>Decreased filtration processes</p> Signup and view all the answers

    What is the result of histotoxic hypoxia on oxygen delivery to tissues?

    <p>Decreased oxygen delivery</p> Signup and view all the answers

    What is the effect of parasympathetic nervous system stimulation on diuresis?

    <p>Increased diuresis</p> Signup and view all the answers

    What is the primary location of the sinoatrial node in mammals?

    <p>Posterior wall of the right atrium</p> Signup and view all the answers

    What is the term for the slow conduction of excitation in the AV node?

    <p>AV delay</p> Signup and view all the answers

    What is the speed of conduction of excitation from the SA node to the left atrium?

    <p>1 m/sec</p> Signup and view all the answers

    Which part of the heart conducts impulses at a speed of 4 m/sec?

    <p>Bundle of His</p> Signup and view all the answers

    What is the result of the slow conduction in the AV node?

    <p>Atrial systole is separated from ventricular systole</p> Signup and view all the answers

    Where does excitation occur in the heart under natural conditions?

    <p>In the sinoatrial node</p> Signup and view all the answers

    What is the function of the cardiac conduction system?

    <p>To produce sequential, rhythmic electrical activities in the myocardium</p> Signup and view all the answers

    Which part of the cardiac conduction system divides into two bundles?

    <p>Bundle of His</p> Signup and view all the answers

    What is the primary function of the peristaltic movement of the stomach?

    <p>Receptive relaxation of the stomach</p> Signup and view all the answers

    What is the result of segmentation in the small intestine?

    <p>Food is mixed in both directions</p> Signup and view all the answers

    What ensures the movement of food substances further in the gastrointestinal tract?

    <p>Peristaltic movement</p> Signup and view all the answers

    What is the primary function of the bundle of His in the heart?

    <p>To allow impulse to go from the atria to the ventricles</p> Signup and view all the answers

    What regulates forestomach motility?

    <p>The nerve center in the medulla oblongata</p> Signup and view all the answers

    What is the main function of the digestive tract's secretory function?

    <p>To secrete digestive juices</p> Signup and view all the answers

    What is responsible for the neutralization of acidic food in the duodenum?

    <p>Alkaline pancreatic juice</p> Signup and view all the answers

    What is the primary effect of progesterone on the uterus during pregnancy?

    <p>It prepares the lining of the uterus to receive the fertilized ovum</p> Signup and view all the answers

    What determines the rate of gastric emptying?

    <p>Both the physical properties and chemical content of food</p> Signup and view all the answers

    What can be seen on an electrocardiogram (ECG)?

    <p>The electrical activity of the heart</p> Signup and view all the answers

    What is the main function of the PR interval in the ECG?

    <p>To reflect the time the electrical impulse takes to travel from the sinus node through the AV node</p> Signup and view all the answers

    What is the primary function of the receptor function in the digestive tract?

    <p>To induce various functions such as gastric emptying reflex and intestinal peristalsis</p> Signup and view all the answers

    What is the primary function of vomiting?

    <p>To remove useless and harmful substances from the stomach</p> Signup and view all the answers

    Which type of ovulation occurs independently of copulation?

    <p>Spontaneous ovulation</p> Signup and view all the answers

    What is the term for the periodic opening and closing of the pyloric sphincter?

    <p>Pyloric reflex</p> Signup and view all the answers

    What is the primary function of progesterone in the corpus luteum?

    <p>To protect pregnancy and stop the growth of new follicles</p> Signup and view all the answers

    What can be judged from the ECG about the heart's cardiac conduction system?

    <p>The anatomical and physiological integrity of the cardiac conduction system</p> Signup and view all the answers

    What is the primary function of the stomach's receptive relaxation?

    <p>To facilitate the movement of food into the esophagus</p> Signup and view all the answers

    What is the primary function of the excretory function in the digestive tract?

    <p>To release substances or metabolites that have not been used by the body into the digestive tract</p> Signup and view all the answers

    What is the result of Starling's law of the intestine?

    <p>A peristaltic wave is generated</p> Signup and view all the answers

    Which of the following is a characteristic of gastric motility?

    <p>The stomach has receptive relaxation</p> Signup and view all the answers

    What is the duration of the QT interval?

    <p>From the beginning of the QRS complex to the end of the T wave</p> Signup and view all the answers

    What is the primary function of the T wave in the ECG?

    <p>To represent the repolarization of the ventricles</p> Signup and view all the answers

    What is the result of the coordinated contractions and relaxations of the muscles in the GI tract?

    <p>Gastrointestinal motility is facilitated</p> Signup and view all the answers

    What is the primary cause of vomiting in case of meningitis?

    <p>Chemical irritants</p> Signup and view all the answers

    Which of the following animals is least likely to vomit?

    <p>Horses</p> Signup and view all the answers

    What is the primary difference between vomiting and regurgitation?

    <p>Vomiting is active, while regurgitation is passive</p> Signup and view all the answers

    What is the primary cause of central vomiting?

    <p>Conditioned reflexes</p> Signup and view all the answers

    What is the term for the passive, retrograde expulsion of previously swallowed material from the esophagus, stomach, or rumen?

    <p>Regurgitation</p> Signup and view all the answers

    Which of the following is a common cause of regurgitation?

    <p>All of the above</p> Signup and view all the answers

    What is the primary reason horses are less likely to vomit?

    <p>Their stomach and esophagus structure</p> Signup and view all the answers

    Which of the following is NOT a common cause of vomiting?

    <p>Respiratory system disorders</p> Signup and view all the answers

    What is the primary mechanism by which the respiratory system influences heart rate?

    <p>Enhanced venous return to the heart through the respiratory pump</p> Signup and view all the answers

    What is the result of increased CO2 in the blood on breathing?

    <p>Increased breathing rate</p> Signup and view all the answers

    What is the role of the lungs in the regulation of blood pressure?

    <p>Conversion of angiotensin I to angiotensin II</p> Signup and view all the answers

    What is the term for the rhythmic oscillations in blood pressure that correspond to the heart rhythm?

    <p>Pulsatory oscillations</p> Signup and view all the answers

    What is the term for the slow heart rate, typically less than 60 beats per minute?

    <p>Bradycardia</p> Signup and view all the answers

    What is the term for the fast heart rate, typically greater than 100 beats per minute?

    <p>Tachycardia</p> Signup and view all the answers

    What is the term for the abnormal heart rhythm that is not synchronized with the normal heartbeat?

    <p>Sinus arrhythmia</p> Signup and view all the answers

    What is the term for low blood pressure?

    <p>Hypotension</p> Signup and view all the answers

    What is the term for high blood pressure?

    <p>Hypertension</p> Signup and view all the answers

    How do the respiratory and circulatory systems work together to transport respiratory gases?

    <p>Both systems work together to deliver oxygen and remove CO2 from the tissues</p> Signup and view all the answers

    What occurs during inspiration in the respiratory fluctuations, also known as second-order waves?

    <p>Blood pressure decreases</p> Signup and view all the answers

    What is the effect of the parasympathetic nervous system on the heart rate during respiratory sinus arrhythmia?

    <p>Decreases heart rate</p> Signup and view all the answers

    What is the primary function of the enterokinase in the small intestine?

    <p>Converts trypsinogen into active trypsin</p> Signup and view all the answers

    What is the pH of the small intestine juice?

    <p>pH 7.5</p> Signup and view all the answers

    What is the primary function of the villi and microvilli in the small intestine?

    <p>To increase the surface area for digestion and absorption</p> Signup and view all the answers

    What is the result of the chemical processing of food in the small intestine?

    <p>Breakdown of nutrients into simpler molecules</p> Signup and view all the answers

    What is the primary function of the aminopeptidases in the small intestine?

    <p>Splits amino groups</p> Signup and view all the answers

    What is the term for the abnormal variation of the sinus rhythm, characterized by irregularities on the ECG?

    <p>Sinus arrhythmia</p> Signup and view all the answers

    What is the primary function of the protozoa in the small intestine?

    <p>Catch and digest bacteria</p> Signup and view all the answers

    What is the result of the digestion of food in the small intestine?

    <p>Breakdown of nutrients into simpler molecules</p> Signup and view all the answers

    What is the primary function of the Myenteric Plexus in the gastrointestinal tract?

    <p>Controlling gastrointestinal motility</p> Signup and view all the answers

    Which of the following neurotransmitters is released by parasympathetic fibers and excitatory neurons in the Enteric Nervous System?

    <p>Acetylcholine (ACh)</p> Signup and view all the answers

    What is the primary function of the Vagus Nerve in the gastrointestinal tract?

    <p>Promoting intestinal juice secretion</p> Signup and view all the answers

    What is the term for the coordinated contractions and relaxations of the muscles necessary to move contents from the mouth to the anus?

    <p>Gastrointestinal motility</p> Signup and view all the answers

    Which of the following types of arteries is characterized by its ability to equalize blood flow, shrinking and stretching according to the volume of blood?

    <p>Elastic type</p> Signup and view all the answers

    What is the primary function of the Submucosal Plexus in the gastrointestinal tract?

    <p>Directly regulating enzyme and mucus secretion from the intestinal glands</p> Signup and view all the answers

    What is the result of the accumulation of serotonin (5-HT) in the gastrointestinal tract?

    <p>Stimulation of intestinal juice secretion</p> Signup and view all the answers

    What is the primary function of the Sympathetic Nervous System in the gastrointestinal tract?

    <p>Inhibiting intestinal juice secretion</p> Signup and view all the answers

    Which of the following types of motility is characterized by the simultaneous contraction of intestinal muscle above an intraluminal stimulus and relaxation of muscle below the stimulus?

    <p>Peristaltic motility</p> Signup and view all the answers

    What is the primary function of Nitric Oxide (NO) in the Enteric Nervous System?

    <p>Influencing smooth muscle relaxation and modulating secretion</p> Signup and view all the answers

    What is the primary function of peristaltic waves in the large intestine?

    <p>To promote water, mineral, and other substance reabsorption</p> Signup and view all the answers

    What is the mechanism by which molecules with poor diffusion in lipids pass through the capillary wall?

    <p>Active transport</p> Signup and view all the answers

    What is the primary function of capillaries in the circulatory system?

    <p>To regulate the flow of blood to tissues and organs</p> Signup and view all the answers

    What is the direction of substance movement in diffusion?

    <p>From higher concentration to lower concentration</p> Signup and view all the answers

    What is the result of the action of primary active transport in the capillary wall?

    <p>A decrease in the concentration of substances in the blood</p> Signup and view all the answers

    What is the primary factor that determines the number of capillaries in different organs?

    <p>The intensity of metabolism</p> Signup and view all the answers

    What is the result of the expansion and opening of capillaries in the skin?

    <p>An increase in skin temperature and pink color</p> Signup and view all the answers

    What is the primary mechanism by which substances move through the capillary wall during filtration?

    <p>Hydrostatic pressure</p> Signup and view all the answers

    What is the effect of sympathetic nervous system stimulation on capillary blood flow?

    <p>A decrease in capillary blood flow</p> Signup and view all the answers

    What is the primary function of the capillary wall in the circulatory system?

    <p>To facilitate the exchange of substances</p> Signup and view all the answers

    What is the primary function of the respiratory system with regards to thermoregulation?

    <p>To regulate body temperature</p> Signup and view all the answers

    What is the role of the sacral segments of the spine in the defecation process?

    <p>To act as the center of regulation for the defecation reflex</p> Signup and view all the answers

    What is the primary function of colostrum in relation to the offspring?

    <p>To increase the probability of survival for the offspring</p> Signup and view all the answers

    What is the difference between the solubility of CO2 and O2 in the lung functional membrane?

    <p>CO2 is 20 times more soluble than O2</p> Signup and view all the answers

    What is the primary function of the respiratory system in relation to blood pressure?

    <p>To regulate blood pressure through the renin-angiotensin-aldosterone system</p> Signup and view all the answers

    What is the role of the lung functional membrane in the process of gas exchange?

    <p>It facilitates the diffusion of gases</p> Signup and view all the answers

    What is the primary function of the cerebral cortex in the defecation process?

    <p>To exert partial control over the defecation reflex</p> Signup and view all the answers

    What is the primary function of the angiotensin II conversion in the respiratory system?

    <p>To promote the production of norepinephrine and vasopressin</p> Signup and view all the answers

    What is the primary function of the exocrine pancreas?

    <p>Secretes digestive enzymes into the small intestine</p> Signup and view all the answers

    What is the main component of pancreatic juice that gives it an alkaline reaction?

    <p>Sodium bicarbonate</p> Signup and view all the answers

    Which hormone is responsible for stimulating the pancreas to secrete more digestive enzymes?

    <p>Cholecystokinin</p> Signup and view all the answers

    What is the function of trypsinogen in the small intestine?

    <p>Breaks down proteins into peptides and amino acids</p> Signup and view all the answers

    What is the function of alpha cells in the pancreas?

    <p>Secrete glucagon to raise blood glucose levels</p> Signup and view all the answers

    What is the main difference between trypsinogen and chymotrypsinogen?

    <p>Trypsinogen is activated by enterokinase, while chymotrypsinogen is activated by trypsin</p> Signup and view all the answers

    What is the function of delta cells in the pancreas?

    <p>Secrete somatostatin to regulate pancreatic function</p> Signup and view all the answers

    What is the average volume of pancreatic juice produced per day in humans?

    <p>0.8 liters</p> Signup and view all the answers

    What is the primary function of secretin in the stomach?

    <p>Inhibits the secretion of gastrin</p> Signup and view all the answers

    What is the primary function of cholecystokinin (CCK) or pancreozymin?

    <p>Stimulates the release of enzymes like amylase, lipase, trypsin, etc. in pancreatic juice</p> Signup and view all the answers

    What is the primary function of lymphatic capillaries?

    <p>To allow substances and fluid to pass quickly from the tissues into the lymphatic capillaries</p> Signup and view all the answers

    What is the primary function of Sertoli cells?

    <p>To support the developing spermatozoa mechanically and supply nutrients</p> Signup and view all the answers

    What is the primary function of Leydig cells?

    <p>To produce testosterone that stimulates the production of spermatozoa</p> Signup and view all the answers

    What is the primary function of the large intestine?

    <p>To reabsorb water and electrolytes, and to facilitate the fermentation of undigested carbohydrates</p> Signup and view all the answers

    What promotes lymphatic flow?

    <p>All of the above</p> Signup and view all the answers

    What is the primary function of the lymphatic system?

    <p>To facilitate the tissue drainage and defense function</p> Signup and view all the answers

    What is the primary function of immunoglobulins in colostrum?

    <p>Help protect against environmental microorganisms</p> Signup and view all the answers

    Where do immunoglobulins pass directly in ruminants?

    <p>From the esophagus to the abomasum and small intestine</p> Signup and view all the answers

    When can immunoglobulins be absorbed from the small intestine?

    <p>Only during the first 6 hours of life</p> Signup and view all the answers

    What happens to the ability to absorb immunoglobulins over time?

    <p>It decreases and then stops</p> Signup and view all the answers

    What is the result of not receiving colostrum in young animals?

    <p>They grow more slowly and not to their full potential</p> Signup and view all the answers

    What is the primary function of insulin in the body?

    <p>To promote nutrient incorporation into cellular stores</p> Signup and view all the answers

    What is the effect of insulin on glucose metabolism?

    <p>It stimulates glycogen synthesis</p> Signup and view all the answers

    What is the result of insulin activity on amino acid metabolism?

    <p>It stimulates protein synthesis</p> Signup and view all the answers

    What is the primary function of the innate immune system's first line of cellular defense?

    <p>To phagocytose foreign particles</p> Signup and view all the answers

    What is the main function of macrophages in the innate immune system?

    <p>To engulf and digest foreign particles and microorganisms</p> Signup and view all the answers

    What is the role of natural killer cells in the innate immune system?

    <p>To kill virus-infected and cancer cells</p> Signup and view all the answers

    What is the primary function of B-lymphocytes in the adaptive immune system?

    <p>To release antibodies against pathogens</p> Signup and view all the answers

    What is the main function of the adaptive immune system?

    <p>To recognize and respond to specific pathogens</p> Signup and view all the answers

    What is the primary function of T-lymphocytes in the adaptive immune system?

    <p>To kill intracellular antigens</p> Signup and view all the answers

    What is the role of opsonins in the innate immune system?

    <p>To mark pathogens for phagocytosis</p> Signup and view all the answers

    What is the primary function of the skin in the innate immune system?

    <p>To provide a physical barrier against pathogens</p> Signup and view all the answers

    What is the primary function of lipids in the body?

    <p>To provide energy and store energy in adipose tissue</p> Signup and view all the answers

    What is the characteristic of triglycerides?

    <p>They are soluble in nonpolar solvents</p> Signup and view all the answers

    What is the function of phospholipids in the body?

    <p>To bring water and fat together and act as emulsifiers</p> Signup and view all the answers

    What is the role of lipids in the absorption of fat-soluble vitamins?

    <p>They facilitate the absorption of fat-soluble vitamins</p> Signup and view all the answers

    What is the function of waxes produced by skin glands?

    <p>To keep the skin lubricated and water-proof</p> Signup and view all the answers

    What is the characteristic of neutral lipids?

    <p>They are relatively insoluble in water</p> Signup and view all the answers

    What is the function of lipoproteins in the body?

    <p>To synthesize lipids and transport them in blood</p> Signup and view all the answers

    What is the physiological meaning of brown fat?

    <p>It serves as energy source</p> Signup and view all the answers

    What is the role of lipids in the protection of kidneys and intestines?

    <p>They facilitate the protection of kidneys and intestines</p> Signup and view all the answers

    What is the characteristic of complex lipids?

    <p>They contain fatty acids, alcohol, and phosphoric acid residue</p> Signup and view all the answers

    What is the primary function of structural lipoproteins?

    <p>To act as a surfactant in lungs and eye</p> Signup and view all the answers

    What is the characteristic feature of veins?

    <p>They stretch easily and fill with blood</p> Signup and view all the answers

    What promotes the return of blood through veins to the heart?

    <p>Skeletal muscles and venous valves</p> Signup and view all the answers

    What is the effect of hunger on the body?

    <p>It activates the hypothalamus and afferent nerves</p> Signup and view all the answers

    What is the primary function of chylomicrons?

    <p>To transport lipids from the diet to the liver</p> Signup and view all the answers

    What is the result of venous valves 'disappearing' with age?

    <p>Blood accumulates in the veins of the legs</p> Signup and view all the answers

    What is the primary location of brown adipose tissue?

    <p>In front of and between the shoulder blades, and around the kidneys</p> Signup and view all the answers

    What is the effect of inspiration on blood flow?

    <p>It makes it easier for blood to flow into the thoracic veins</p> Signup and view all the answers

    What is the characteristic feature of venous pulse?

    <p>It is a volume fluctuation in the veins</p> Signup and view all the answers

    What is the primary regulator of appetite?

    <p>The hypothalamus</p> Signup and view all the answers

    What is the primary function of ghrelin hormone?

    <p>Appetite stimulant</p> Signup and view all the answers

    What is the primary function of leptin hormone?

    <p>Appetite suppressant</p> Signup and view all the answers

    What is the primary function of PYY hormone?

    <p>Appetite suppressant</p> Signup and view all the answers

    What percentage of digestible cellulose is broken down in the forestomachs of ruminants?

    <p>60-70%</p> Signup and view all the answers

    What is the byproduct of cellulose breakdown in the forestomachs of ruminants?

    <p>Volative fatty acids</p> Signup and view all the answers

    What is the function of cellulolytic bacteria in the digestive system of ruminants?

    <p>Breaking down cellulose</p> Signup and view all the answers

    What is the effect of ghrelin release on appetite?

    <p>Appetite stimulation</p> Signup and view all the answers

    What is the primary function of insulin in appetite regulation?

    <p>Appetite suppressant</p> Signup and view all the answers

    What is the primary location of ghrelin production in the body?

    <p>Stomach wall</p> Signup and view all the answers

    What is the effect of leptin on appetite regulation?

    <p>Appetite suppression</p> Signup and view all the answers

    What is the primary function of pulmonary surfactant?

    <p>To reduce surface tension and prevent alveoli collapse</p> Signup and view all the answers

    What is the primary component of phospholipids in terms of their structure?

    <p>Hydrophilic head and two hydrophobic tails</p> Signup and view all the answers

    What is the primary function of phosphorus in the body?

    <p>All of the above</p> Signup and view all the answers

    What is the result of the action of calcitonin on calcium levels in the blood?

    <p>It decreases calcium levels</p> Signup and view all the answers

    What is the role of parathyroid hormone in regulating calcium and phosphorus levels?

    <p>It increases calcium levels and decreases phosphorus levels</p> Signup and view all the answers

    What is the result of surfactant's anti-inflammatory action?

    <p>It promotes the activity of phagocytes</p> Signup and view all the answers

    What is the function of phospholipids in the alveoli?

    <p>To reduce surface tension and prevent alveoli collapse</p> Signup and view all the answers

    What is the result of phosphorus deficiency in the body?

    <p>All of the above</p> Signup and view all the answers

    What is the primary mechanism by which ruminants can utilize non-protein nitrogen compounds?

    <p>By synthesizing their own protein using ammonia</p> Signup and view all the answers

    What is the primary function of the omasum in the forestomach?

    <p>To absorb a large amount of water</p> Signup and view all the answers

    What is the percentage of methane produced by fermentation processes in the forestomachs that is excreted by belching?

    <p>95%</p> Signup and view all the answers

    What is the term for the type of conduction of excitation in myelinated nerve fibers?

    <p>Saltatory conduction</p> Signup and view all the answers

    What is the primary function of the myelin sheath in myelinated nerve fibers?

    <p>To provide electrical insulation</p> Signup and view all the answers

    What is the result of the accumulation of CO2 in the forestomachs?

    <p>The neutralization of volatile fatty acids</p> Signup and view all the answers

    What is the primary mechanism by which excitation is conducted in unmyelinated nerve fibers?

    <p>Through the movement of sodium and potassium ions</p> Signup and view all the answers

    What is the percentage of the total greenhouse gases produced by the agricultural sector that is attributed to cattle?

    <p>80%</p> Signup and view all the answers

    What is the primary cause of phosphorus deficiency in grazing livestock worldwide?

    <p>High levels of phytic acid in plant materials</p> Signup and view all the answers

    What is the ratio of dietary Ca to P that can interfere with Ca absorption?

    <p>Less than 1:5</p> Signup and view all the answers

    Which of the following is NOT a type of non-elastic resistance in the respiratory system?

    <p>Elastic resistance</p> Signup and view all the answers

    What is the primary mechanism by which bronchoconstriction occurs?

    <p>Activation of cholinergic smooth myocytes</p> Signup and view all the answers

    What is the primary factor that affects the elastic resistance in the respiratory system?

    <p>All of the above</p> Signup and view all the answers

    What is the primary location where airflow is laminar in the respiratory system?

    <p>Smallest bronchi and bronchioles</p> Signup and view all the answers

    What is the primary function of the parasympathetic nervous system in the bronchi?

    <p>Causes bronchoconstriction</p> Signup and view all the answers

    What is the primary source of phosphorus that is highly available to monogastric animals?

    <p>Inorganic mineral sources such as sodium phosphate</p> Signup and view all the answers

    What is the primary function of the hormone erythropoietin?

    <p>To promote the differentiation of erythroblasts into erythrocytes</p> Signup and view all the answers

    What is the role of thyroxine in the process of erythropoiesis?

    <p>It stimulates the production of erythropoietin</p> Signup and view all the answers

    What is the primary mechanism of neural regulation of erythropoiesis?

    <p>Neural regulation through the action of sympathetic nerves</p> Signup and view all the answers

    What is the effect of renal hypoxia on the production of erythropoietin?

    <p>It increases the production of erythropoietin</p> Signup and view all the answers

    What is the primary function of the reflex arc?

    <p>To maintain homeostasis</p> Signup and view all the answers

    What is the difference between inborn and acquired reflexes?

    <p>Inborn reflexes are innate, while acquired reflexes are acquired through learning</p> Signup and view all the answers

    What is the role of the internouron in the central nervous system?

    <p>It integrates sensory information and transmits it to the motor neuron</p> Signup and view all the answers

    What is the speed of conduction of impulses in the fastest nerve fibers?

    <p>120 m/s</p> Signup and view all the answers

    What is the characteristic of unconditioned reflexes?

    <p>They have a clear connection between action on the receptor and a certain response</p> Signup and view all the answers

    What happens to damaged and aged erythrocytes in the spleen?

    <p>They are identified by macrophages and phagocytized</p> Signup and view all the answers

    What is the fate of the heme portion of hemoglobin during hemolysis?

    <p>It undergoes chemical degradation and becomes a waste product</p> Signup and view all the answers

    Why is increased hemolysis dangerous?

    <p>It causes poisoning with K+ ions</p> Signup and view all the answers

    What is the function of erythropoietin?

    <p>It acts on stem cells and stimulates their mitosis</p> Signup and view all the answers

    What is the result of jaundice?

    <p>An excessive accumulation of bilirubin in the blood</p> Signup and view all the answers

    What is the role of macrophages in the process of hemolysis?

    <p>They identify and phagocytize damaged and aged erythrocytes</p> Signup and view all the answers

    What is the fate of iron released during hemolysis?

    <p>It is transported to the bone marrow for reuse</p> Signup and view all the answers

    What is the primary function of calmodulin in the process of neurotransmitter release?

    <p>To bind with Ca2+ and trigger the migration of vesicles towards the presynaptic membrane</p> Signup and view all the answers

    What is the direction of excitation transfer in a chemical synapse?

    <p>From presynaptic to postsynaptic membrane</p> Signup and view all the answers

    What is the time period from neurotransmitter release to receptor channel binding?

    <p>One millionth of a second</p> Signup and view all the answers

    What is the term for the time when the excitation spreads through the synapse?

    <p>Synaptic delay</p> Signup and view all the answers

    Why do receptors which react to neurotransmitters exist only on the postsynaptic membrane?

    <p>Because the receptors are specific to the postsynaptic membrane</p> Signup and view all the answers

    Study Notes

    Cardiac Cycle

    • The cardiac cycle is a rhythmic, coordinated contraction and relaxation of individual parts of the heart
    • The entire cardiac cycle lasts for:
      • 0.8 seconds in humans
      • 1.4 seconds in horses
    • There are three phases in the cardiac cycle:
      • Atrial systole (approximately 0.1 seconds)
      • Ventricular systole (approximately 0.3 seconds)
      • Total diastole or pause (approximately 0.4 seconds)

    Ventricular Filling

    • At the beginning of the cardiac cycle, both the atria and ventricles are relaxed (diastole)
    • Blood flows into the right atrium from the superior and inferior venae cavae and the coronary sinus
    • Blood flows into the left atrium from the four pulmonary veins
    • The two atrioventricular valves (tricuspid and mitral valves) are open, allowing blood to flow from the atria into the ventricles
    • Approximately 70-80% of ventricular filling occurs during this phase
    • The two semilunar valves (pulmonary and aortic valves) are closed, preventing backflow of blood into the right and left ventricles

    Atrial Contraction

    • As the atrial muscles contract, pressure rises within the atria
    • Blood is pumped into the ventricles through the open atrioventricular valves
    • Atrial contraction contributes the remaining 20-30% of filling
    • Atrial systole ends prior to ventricular systole, as the atrial muscle returns to diastole

    Ventricular Systole

    • Isovolumetric contraction:
      • The muscles in the ventricle contract, causing pressure to rise within the chamber
      • Blood pressure quickly rises above that of the atria, causing blood to flow back toward the atria
      • The tricuspid and mitral valves close, and the volume of blood within the chamber remains constant
    • Ventricular ejection phase:
      • The contraction of the ventricular muscle raises the pressure within the ventricle
      • Blood is pumped from the heart, pushing open the pulmonary and aortic semilunar valves
      • Pressure generated by the left ventricle is appreciably greater than the pressure generated by the right ventricle

    Diastole

    • Early diastole (isovolumetric relaxation):
      • Ventricular relaxation causes pressure on the remaining blood within the ventricle to fall
      • When pressure within the ventricles drops below pressure in both the pulmonary trunk and aorta, blood flows back toward the heart
      • The semilunar valves close to prevent backflow into the heart
    • Late diastole:
      • As the ventricular muscle relaxes, pressure on the blood within the ventricles drops even further
      • Blood flows from the atria into the ventricles, pushing open the tricuspid and mitral valves
      • The atrioventricular valves are open, and the semilunar valves remain closed

    Process of Normal Expiration

    • Expiration is a passive process impacted by:
      • Relaxation of the respiratory muscles
      • Lung elastic powers
      • Gravity of the chest cavity
      • Organs of the abdominal cavity that press on the diaphragm
    • Self-regulation of expiration:
      • During inspiration, lungs stretch, and impulses through the afferent parasympathetic vagus fibers go to the respiratory center
      • Inspiratory neurons are suppressed, and they stop sending impulses to the spinal cord
      • Respiratory muscles relax, and lungs deflate
      • Expiratory neurons in the medulla oblongata are activated, inhibiting inspiratory neurons
      • Pons in the brain switches from inspiration to expiration
      • Information to the spinal cord is not sent, and the diaphragm and external muscles of the chest relax
      • The chest deflates, pressure in the pleural cavity increases
      • Lungs contract, and air flows out

    Pancreas and Hormones

    • Exocrine secretion: digestive enzymes target the duodenum
    • Endocrine secretion: pancreatic islets (islets of Langerhans) produce:
      • α cells: glucagon (increases glucose level in the blood)
      • β cells: insulin (decreases glucose level in the blood), amylin (centrally acting, neuroendocrine hormone)
      • δ cells: somatostatin (inhibits the release of glucagon and insulin)
      • PP cells: pancreatic polypeptide (inhibits gastrointestinal movement and pancreatic secretion, gallbladder contraction)

    Physiological Roles of Hormones

    • Insulin:
      • Absolutely necessary for life-support
      • Impacts metabolism of proteins, carbohydrates, and fats
      • Main target organ is the liver
    • Glucagon:
      • Impacts metabolism of proteins, carbohydrates, and fats
      • Increases glucose level in the blood
    • Hypoglycemia:
      • Decreases blood glucose level
      • Increases permeability of the cell membrane to glucose
      • Increases glycogen synthesis in the liver and muscles
      • Increases protein and fat synthesis
    • Hyperglycemia:
      • Increases blood glucose level
      • Glycosuria begins (renal threshold for glucose is 10 mmol/L in dogs and 16 mmol/L in cats)
      • Polyuria and polydipsia occur
      • Fat oxidation (degradation) processes stop in the intermediate stage
      • Incompletely oxidized metabolic products (ketones) accumulate in the body, leading to acidosis

    Types of Hypoxia

    • Hypoxic hypoxia: decreased pO2 in arterial blood
    • Anemic hypoxia: pO2 in arterial blood is normal, but the amount of hemoglobin is decreased
    • Ischemic (stagnant) hypoxia: arterial blood supply to tissues is impaired
    • Histotoxic hypoxia: pO2 and transport of O2 is normal, but tissues are unable to use O2 due to toxins

    Neural Regulation of Renal Functions

    • Sympathetic nervous system:
      • Kidney blood vessels constrict
      • Blood supply to the kidneys decreases
      • Filtration processes decrease
      • Diuresis decreases
    • Parasympathetic nervous system:
      • Blood vessels dilate
      • Blood supply to the kidneys increases
      • Filtration processes increase
      • Diuresis increases
    • In case of pain:
      • Regulation through the cerebral cortex
      • Increases the release of ADH in the hypothalamus
      • Sympathetic nervous system intensifies
      • Blood vessels constrict
      • Decreases blood supply to the kidneys
      • Decreases filtration processes and diuresis

    Cardiac Conduction System

    • The cardiac conduction system is responsible for generating and conducting electrical impulses in the heart.
    • It consists of five elements:
      • Sinoatrial (SA) node: generates the action potential and is located in the posterior wall of the right atrium.
      • Atrioventricular (AV) node: located in the interatrial septum.
      • Bundle of His: divides into two bundles (left and right).
      • Bundle branches: branch into Purkinje fibers.
      • Purkinje fibers: branch into the myocardium.
    • The speed of conduction of excitation in the heart varies in different parts:
      • SA node to left atrium: 1 m/sec.
      • AV node: 0.1 m/sec (slowest conduction speed, known as AV delay).
      • Bundle of His: 4 m/sec (fastest conduction speed).
      • Ventricles: approximately 1 m/sec.

    Functions of the Digestive Tract

    • The digestive tract has five main functions:
      • Secretory function: glands secrete digestive juices.
      • Motor function: performs mechanical processing of food.
      • Absorption function: allows water and broken nutrients to enter the bloodstream and lymph.
      • Excretory function: releases substances or metabolites not used by the body.
      • Incretory function: hormones produced by endocrine cells enter the bloodstream.
      • Receptor function: induces various functions, such as gastric emptying reflex and intestinal peristalsis.

    Physiological Effects of Progesterone

    • Progesterone is a pregnancy protection hormone produced in the corpus luteum.
    • Its effects on the uterus and mammary glands:
      • Prepares the uterus for fertilization.
      • Promotes the fixation of the fertilized ovum.
      • Inhibits the effect of oxytocin on the smooth muscle of the uterus.
      • Inhibits the development of follicles in the ovaries.
      • Promotes the development of mammary gland alveoli.
      • Protects pregnancy and stops the growth of new follicles.
      • Stimulates udder development during pregnancy.
      • Keeps parturition and lactogenesis in check.

    Electrocardiogram (ECG)

    • The ECG records the electrical activity of the heart.
    • It provides information about:
      • The origin of excitation in the heart.
      • Cardiac arrhythmias.
      • Transmission of excitation in the heart.
      • Metabolic disorders in the myocardium.
      • Heart pathologies, such as heart attack.
    • Waves and intervals on the ECG:
      • P wave: represents atrial depolarization.
      • PR interval: time between the start of the P wave and the start of the QRS complex.
      • QRS complex: represents rapid depolarization of the ventricles.
      • ST segment: represents the period when the ventricles are depolarized.
      • T wave: represents ventricular repolarization.
      • QT interval: duration of ventricular depolarization and repolarization.
      • RR interval: duration of the ventricular cardiac cycle.

    Spontaneous and Induced Ovulation

    • Types of ovulation:
      • Spontaneous ovulation: occurs independently of copulation (e.g., cows, sheep, dogs, humans, horses).
      • Induced ovulation (reflex ovulation): requires copulation for ovulation to occur (e.g., cats, mink, rabbits, camels).

    Motility of the Stomach

    • Gastric motility:
      • Provided by three layers of muscles (external, middle, and internal).
      • Ensures mechanical processing of food.
      • Tonic movements: typical of an empty stomach.
      • Peristaltic movements: typical of a full stomach.
      • Receptive relaxation: allows the stomach to stretch without high resistance and pressure increase.
    • Evacuation of food from the stomach to the duodenum:
      • Regulated by the pyloric reflex.
      • pH receptors and stretch receptors stimulate the pyloric reflex.
      • Alkaline pancreatic juice, bile, and duodenal juice neutralize the acidity of the food.
      • Gastric emptying rate depends on the chemical content and physical properties of the food.

    Vomiting and Regurgitation

    • Vomiting: a protective reaction to remove harmful substances from the stomach.
      • Caused by direct irritation of receptors in the tongue, throat, vestibular apparatus, and gastric mucosa.
      • Caused by central irritation of the vomiting center.
    • Regurgitation: the passive, retrograde expulsion of previously swallowed material from the esophagus, stomach, or rumen.
      • Often a clinical symptom, but can also be associated with a conditioned reflex to feed young.

    Respiration Impact on Heart Rate and Blood Pressure

    • Respiratory function influences the venous return to the heart, enhancing venous return through the respiratory pump.
    • Increased pressure difference between the abdominal and thoracic vena cava during inspiration increases venous return to the heart.
    • Respiratory system participates in the regulation of acid-base balance, responding to changes in CO2 levels to normalize H+ concentration.
    • Respiratory system regulates blood pressure via the renin angiotensin-aldosterone system, converting Angiotensin I to Angiotensin II in the lungs.

    Respiratory-Induced Fluctuations in Blood Pressure

    • Pulsatory oscillations (first-degree waves) correspond to the heart rhythm, with pressure increasing after ventricular systole and decreasing after total diastole.
    • Respiratory fluctuations (second-order waves) correspond to the rhythm of breathing, with blood pressure decreasing during inspiration and increasing during expiration.

    Sinus Rhythm and Arrhythmia

    • Sinus rhythm is a normal heart rhythm, while sinus arrhythmia is a normal variation of sinus rhythm with irregularities on ECG.
    • Sinus rhythm is influenced by the autonomic nervous system, with the parasympathetic nervous system slowing down the heart rate and the sympathetic nervous system increasing it.

    Hypertension and Hypotension

    • Hypertension is high blood pressure, while hypotension is low blood pressure.

    Digestion in the Small Intestine

    • The small intestine is responsible for digestion and absorption of nutrients from food.
    • Digestion occurs through mechanical and chemical processing, with the help of digestive enzymes and juices.
    • The small intestine has a large surface area with villi and microvilli, increasing the absorption of nutrients.

    Regulation of Digestion

    • The autonomic nervous system, including the parasympathetic and sympathetic nervous systems, regulates digestion and secretion of digestive juices.
    • Neurotransmitters and neuromodulators, such as acetylcholine, serotonin, and vasoactive intestinal peptide, play a crucial role in regulating digestion.

    Arteries

    • Arteries are elastic blood vessels that equalize blood flow, making it continuous.
    • Arteries are divided into three types based on their structure: elastic type, muscle type, and mixed type.

    Motility in the Small and Large Intestine

    • Motility is the coordinated contractions and relaxations of muscles necessary to move contents from the mouth to the anus.
    • Peristalsis is a type of motility that occurs in the small intestine, ensuring mixing of food substances, mixing with digestive juices, and pressing the food substances to the intestinal wall.
    • The large intestine has slower movements than the small intestine, with peristaltic, segmental, and antiperistaltic waves.

    Functions of Capillaries

    • Capillaries have a circulatory function, regulating the flow of blood to tissues and organs, and a metabolic function, associated with the movement of substances through the capillary wall.
    • The number of capillaries in different organs depends on their intensity of metabolism.

    Movement of Substances through the Capillary Wall

    • Substances move through the capillary wall through diffusion, osmosis, active transport, filtration, and reabsorption.
    • Diffusion occurs through a concentration gradient, with passive diffusion occurring more slowly and active diffusion occurring more quickly.
    • Osmosis occurs due to osmotic pressure gradient, with dissolved substances moving from higher concentration to lower concentration.
    • Active transport involves the use of energy to move substances against their concentration gradient.
    • Filtration and reabsorption occur due to hydrostatic and oncotic pressure gradients, with filtration occurring at the arterial end and reabsorption occurring at the venous end of the capillaries.

    Pancreas Function

    • The pancreas has both exocrine and endocrine functions.
    • Exocrine function: • Synthesizes and secretes enzymes (zymogens) to avoid self-digestion. • Secretes bicarbonate ions to neutralize acidic chyme from the stomach. • Controlled by hormones gastrin, cholecystokinin, and secretin from the stomach and duodenum in response to food.

    Pancreatic Juice

    • Organic components of pancreatic juice include: • Proteases (zymogens): trypsinogen, chymotrypsinogen, carboxypeptidase, and aminopeptidase. • Lipases: pancreatic lipases. • Amylases: α-amylase, maltase, lactase, and sucrase.
    • Inorganic component: Na bicarbonate, which gives an alkaline reaction.

    Humoral Regulation of Pancreatic Secretion

    • Secretin: • Stimulates the release of sodium bicarbonate in pancreatic juice. • Inhibits gastrin secretion in the stomach. • Stimulates liver secretion of bile. • Regulates water homeostasis in the body.
    • Cholecystokinin (CCK) or Pancreozymin: • Stimulates the pancreas to release enzymes like amylase, lipase, and trypsin. • Stimulates the release of stored bile from the gallbladder. • Inhibits motility and closes the pyloric sphincter.

    Lymph Formation and Circulation

    • Lymph forms when blood plasma passes through capillary walls into the tissue fluid.
    • Lymphatic capillaries are highly permeable, allowing substances to pass quickly from tissues into the lymph.
    • Lymph has a composition similar to blood plasma but with less protein.
    • Lymphatic flow is promoted by: • Smooth muscle elements (lymphangions) in lymphatic vessels that contract regularly. • Skeletal muscle contractions. • Respiratory movements.

    Leydig and Sertoli Cells

    • Leydig cells: • Produce testosterone, stimulating sperm production, male sex characteristics, psychological development, and sex drive. • Located outside seminiferous tubules.
    • Sertoli cells: • Support the development of spermatozoa mechanically. • Supply nutrients to developing spermatozoa. • Participate in the regulation of spermatogonia differentiation into spermatozoa. • Produce inhibin, which inhibits FSH secretion from the anterior pituitary gland.

    Digestion in the Large Intestine

    • The large intestine mainly absorbs water and salts.
    • The pH of chyme is important for enzyme activity.
    • Fermentation and putrefaction processes occur in the large intestine, producing vitamins (B6, K, biotin, folic acid).
    • Defecation is a combination of voluntary and involuntary processes regulated by the sacral segments of the spine and the cerebral cortex.

    Respiratory System Functions

    • Gas exchange between the lungs and blood by diffusion.
    • Maintains acid-base balance in the body.
    • Acts as an excretory system, eliminating water, volatile substances, and CO2.
    • Participates in thermoregulation, venous return to the heart, and humoral regulation.
    • Provides immune protection, analyzes inhaled air, heats, moistens, and cleans it.

    Colostrum

    • A secretion accumulating in the mammary glands before parturition.
    • Different composition than milk, with more fat, proteins, minerals, and vitamins.
    • Contains immunoglobulins, which provide passive immunity to offspring.
    • Helps protect against infection, and is critical for young animals in industrial conditions.

    Insulin Release and Function

    • Insulin is released from beta cells into the blood in response to glucose, amino acids, and fatty acids.
    • Stimulates cellular uptake of glucose, amino acids, and fatty acids, promoting nutrient incorporation into cellular stores.
    • Lowers blood glucose, amino acid, and fatty acid concentrations.
    • Promotes glycogen synthesis, inhibits gluconeogenesis, and stimulates protein synthesis and triglyceride synthesis.

    Types of Immunity

    • Innate (inborn) immune system: • Mediates rapid response to pathogens. • Responds without prior exposure. • Not specific. • Includes physical barriers, antimicrobial proteins, and phagocytosis.
    • Adaptive (acquired) immune system: • Develops after birth. • Reacts more slowly. • More effective. • Highly specific. • Involves lymphocytes (B-cells and T-cells).

    Lipids in the Body

    • Lipids are a group of naturally occurring molecules that include fats, sterols, phospholipids, and others
    • Made up of glycerol and fatty acids
    • Relatively insoluble in water, but soluble in nonpolar solvents like ether, chloroform, benzole, and acetone
    • Stored in adipose tissue, serving as thermal and electrical insulators
    • Important components of cell and mitochondrial membranes
    • Lipoproteins serve as a means of transport of lipids in blood

    Types of Lipids

    • Neutral lipids (fats and oils)
      • Functions: energy source, insulation, protection, carrier for fat-soluble vitamins
    • Polar lipids (phospholipids and glycolipids)
      • Phospholipids: structural components of cell membranes, emulsifiers, and important for lipid absorption and transport
      • Glycolipids: lipids containing fatty acid, sphingosine, and carbohydrate
    • Brown adipose tissue: high density of mitochondria, present in newborn animals, and important for heat generation

    Veins and Blood Circulation

    • Veins are volume or capacity blood vessels due to their ability to stretch easily and fill with blood
    • Veins regulate blood flow to the heart, especially from the extremities against gravity
    • Factors promoting blood circulation in veins:
      • Skeletal muscles
      • Venous valves
      • Respiratory movements
      • Suction action of the heart
    • Venous pulse: volume fluctuations of the veins, detected in veins close to the heart, reflecting the activity of the right side of the heart

    Hormones Regulating Appetite

    • Regulated by a center located in the hypothalamus
    • Feeling of hunger is caused by:
      • Afferent nerves from the stomach and intestines
      • Changes in physical-chemical properties of blood (i.e., "hunger blood")
    • Hormones regulating appetite:
      • Ghrelin: orexigenic (stimulates appetite), released from the stomach wall when empty
      • Leptin: anorexigenic (suppresses appetite), released from adipocytes (fat cells)
      • Insulin: suppresses appetite, released from beta cells in the pancreas
      • PYY (peptide tyrosine tyrosine): suppresses appetite, released from cells in the ileum and colon in response to feeding

    Cellulose Breakdown in Ruminants

    • Cellulose and carbohydrate breakdown in the forestomach of ruminants
    • 60-70% of digestible cellulose is broken down in the forestomach
    • Bacterial enzyme cellulase breaks down cellulose into cellobiose, then further broken down into glucose, eventually forming volatile fatty acids

    Pulmonary Surfactant

    • A surface-active complex of phospholipids and proteins formed by alveolar cells
    • Creates a hydrophobic film lining the internal surface of the lungs
    • Functions:
      • Reduces surface tension
      • Gives alveoli a round shape and prevents collapse during exhalation
      • Has anti-inflammatory action and helps lyse microorganisms
      • Regulates oxygen diffusion through the alveolar wall
      • Prevents fluid accumulation in alveoli
      • Makes breathing easier

    Phosphorus

    • Found in both organic and inorganic forms in the body
    • Most present in bone tissue and teeth (80-85%) and soft tissues and fluids (15-20%)
    • Functions:
      • Important in bone and cartilage composition
      • Component of phospholipids, nucleic acids, and phosphoproteins
      • Involved in energetic processes and cell metabolism
      • Helps maintain normal pH of body fluids
    • Deficiency symptoms:
      • Osteomalacia
      • Rickets
      • Joint stiffness
      • Muscular weakness
      • Pica
      • Reduced growth and reproduction
    • Toxicity symptoms:
      • Kidney stones
      • Interferes with calcium absorption

    Respiratory System Resistance

    • Total resistance of the breathing process consists of non-elastic and elastic resistance
    • Non-elastic resistance (~35%):
      • Viscous resistance (7%)
      • Air flow resistance (28%)
      • Influenced by air flow patterns (laminar or turbulent) and airway diameter
    • Elastic resistance (~65%):
      • Created by chest, respiratory, and lung tissue compliance
      • Influenced by lung volume, body posture, and blood supply

    Protein Splitting in Ruminant Forestomach

    • Proteins broken down into peptides and amino acids by microbial enzymes
    • Amino acids deaminated to form ammonia, which is used by bacteria to synthesize their own proteins
    • Urea circulation: ammonia in liver → urea → salivary glands → saliva → forestomach → urease → ammonia and CO2
    • Nitrogen circulation: ammonia in forestomach → liver → urea → salivary glands → saliva → forestomach
    • Methane and CO2 produced in fermentation process, released through belching and exhalation

    Mechanisms of Conduction of Excitation in Nerve Fibers

    • Unmyelinated nerve fibers:
      • Depolarization and circular powers occur
      • Action potential (AP) propagates along the axon
      • Neurotransmitter release at the synapse
    • Myelinated nerve fibers:
      • Myelin sheath provides electrical insulation
      • Saltatory conduction occurs, where the AP jumps from node to node
      • Thicker nerve fibers have faster conduction

    Erythropoiesis

    • Process of red blood cell production
    • Stimulated by:
      • Decreased partial pressure of oxygen in blood plasma
      • Increased erythropoietin in blood plasma
      • Androgens, thyroxine, and somatotropic hormone
    • Vitamins and minerals essential for RBC maturation:
      • Vitamin PP (niacin)
      • Vitamin B12
      • Iron, copper, and cobalt
    • Erythropoietin production is stimulated by renal hypoxia or extirpation, increased lactic acid, and anemia

    Neural Regulation

    • More precise and faster than humoral regulation
    • Uses nerve fibers to send information to the tissue response group
    • Reflex arc consists of:
      1. Sensory receptor
      2. Sensory (afferent) neuron
      3. Internouron in the central nervous system
      4. Motor (efferent) neuron
      5. Effector (target organ)

    Reflexes

    • Inborn (unconditioned) reflexes:
      • Autonomic (related to internal organs)
      • Somatic (related to skeletal muscles)
    • Acquired (conditioned) reflexes:
      • Developed through temporary connections in the cerebral cortex
      • Serve as mechanisms for adaptation to changing environmental conditions

    Hemolysis

    • Breakdown of red blood cells
    • Physiological hemolysis:
      • Occurs mainly in the spleen and liver
      • Damaged erythrocytes are identified and phagocytized by macrophages
      • Hemoglobin is released and broken down
    • Pathological hemolysis:
      • Can lead to jaundice and anemia
      • Causes include genetic defects, infections, and medications

    Mechanism of Excitation in Chemical Synapses

    • Excitation in chemical synapses occurs when Ca2+ enters the presynaptic cell due to the concentration gradient, being higher outside the cell than inside.
    • The entering Ca2+ binds with calmodulin, a multifunctional intermediate calcium-binding messenger protein, triggering the migration of vesicles filled with neurotransmitters towards the presynaptic membrane.
    • The vesicles release the neurotransmitters, which then travel across the synapse to the postsynaptic membrane.

    Transmission of Excitation

    • The neurotransmitters bind to their specific receptors located only on the postsynaptic membrane, allowing the excitation to be transmitted.
    • The transmission of excitation occurs in one direction, from the presynaptic membrane to the postsynaptic membrane.

    Synaptic Delay

    • The time period between the release of the neurotransmitter and its binding to the receptor channel is less than a millisecond, referred to as the synaptic delay.
    • The synaptic delay is the brief period during which the excitation spreads through the synapse.

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