ACTUAL Physiology Verbal Exam PDF

39. Ticket 77. What is hemostasis? How is it provided? The forming of the primary (white) and definitive (red) blood clot (thrombus). What happens after the formation of the blood clot? Platelets (thrombocytes) Platelets are formed in the r...

39. Ticket 77. What is hemostasis? How is it provided? The forming of the primary (white) and definitive (red) blood clot (thrombus). What happens after the formation of the blood clot? Platelets (thrombocytes) Platelets are formed in the red bone marrow. When coming into contact with an uneven surface in the body, such as the edges of a wound, platelets break down. Biologically active substances are released from platelets and tissue cells. In the first part of the HEMOSTASIS AND BLOOD CLOTTING, when bleeding from the blood vessels begin, platelets stick to the edges of the wound, partially or completely covering the injured blood vessels. Thrombocytes form the so-called a white thrombus that is very unstable and does not adhere well to the edges of the wound. Hemostasis and blood clotting Hemostasis is a physiological process that stops bleeding at the site of injury, which is ensured by complex processes aimed at protecting the body from blood loss when a blood vessel is damaged. The 4 stages of hemostasis are: 1. Narrowing (vasoconstriction) of blood vessels (vascular spasm) 2. Formation of primary platelet plug (hemostatic plug). 3. Formation of definitive blood plug (There are three stages in this process) 4. Ingrowth of fibrous tissue into a blood clot 1. Narrowing (constriction) of blood vessels (vascular spasm). When a vessel is damaged, vascular spasm occurs. In vascular spasm, the smooth muscle in the walls of the vessel contracts dramatically. This smooth muscle tends to constrict the flow of blood. It happens: as a local reflector organism’s response to pain. as a local response to humoral factors released from damaged tissues and erythrocytes (serotonin: induces constriction of injured blood vessels and enhances platelet aggregation to minimize blood loss., thromboxane A2: stimulates activation of new platelets as well as increases platelet aggregation..) 2. Formation of primary platelet plug (hemostatic plug). It is formed when platelets stick to the edge of the wound (adhesion) Then they are activated and stick together (aggregation) It is a multi-step process Non-permanent, the “plug” can be swept away! 3. Formation of definitive blood plug – fibrin filaments are formed, in which blood cells adhere. Three stages are distinguished in this process: Formation of the prothrombin activator complex. When the platelets collapse, thromboplastinogen is released, which turns into thromboplastin, many more factors (at least 10), and Ca2+ are involved, which is absolutely necessary for blood clotting.  Transformation of plasma prothrombin (produced by the liver, requires vitamin K, Ca2+) into thrombin Dissolved fibrinogen turns into fibrin (insoluble), forms the "skeleton" of the thrombus. 4. Ingrowth of fibrous tissue into a blood clot closes the damaged blood vessel site 78. What is glycogen? Why is it beneficial for the animal? Glycogen is a multi-branched polysaccharide that serves as a form of energy storage in animals and fungi. It is the primary storage form of glucose in the body, mainly found in the liver and muscle tissues. Structurally, glycogen is similar to amylopectin (a component of starch) but is more extensively branched and compact. Structure of Glycogen Glucose Units: Glycogen is composed of glucose molecules linked together by α(1→4) glycosidic bonds, with branching points that occur every 8-12 glucose units via α(1→6) glycosidic bonds. Highly Branched: This branching allows for rapid mobilization of glucose when energy is needed. Synthesis and Breakdown Glycogenesis: The process of synthesizing glycogen from glucose, which occurs when there is an excess of glucose in the blood. Glycogenolysis: The breakdown of glycogen to release glucose, which happens when the body requires energy, especially between meals or during physical activity. Benefits of Glycogen for Animals 1. Energy Storage: ○ Quick Energy Release: The branched structure of glycogen allows for quick release of glucose units, providing a rapid source of energy during periods of high demand, such as intense physical activity. ○ Liver Glycogen: Maintains blood glucose levels, ensuring a constant energy supply for the brain and other vital organs. ○ Muscle Glycogen: Provides energy directly to muscle cells during contraction and exercise. 2. Maintaining Blood Sugar Levels: ○ Homeostasis: Glycogen stored in the liver helps regulate blood glucose levels, preventing hypoglycemia (low blood sugar) and providing a steady energy supply. 3. Energy Buffer: ○ Short-Term Energy Reserve: Glycogen acts as a short-term energy buffer, storing glucose when it is abundant (after eating) and releasing it when needed (between meals or during fasting). 4. Support for Metabolic Processes: ○ Metabolic Flexibility: Glycogen allows animals to quickly adapt to changes in energy demand and availability, supporting metabolic processes that require a steady supply of glucose. In summary, glycogen is a crucial energy storage molecule that allows animals to efficiently manage energy resources, maintain blood glucose levels, and support various physiological functions. Its rapid mobilization during periods of energy need makes it an essential component of animal metabolism. 40. Ticket 79. What factors determine the resistance in blood vessels? Describe them. The types of resistance in blood vessels – how does each type impact arterial blood pressure? Vascular resistance is the force that must be overcome for blood to flow through the circulatory system. It is influenced by several factors: Blood viscosity: Thicker blood increases resistance and decreases flow. Blood vessel diameter: Smaller diameters increase resistance and decrease flow. Blood vessel length: Longer vessels increase resistance and decrease flow. Vascular wall properties: More elastic walls lower resistance, while more contractile walls increase resistance. Total cross-sectional area: Larger areas reduce resistance. Key Points 1. Blood Viscosity: ○ Affects flow: Thicker blood (like mud) flows less easily than thinner blood (like water). ○ Influenced by red blood cells and plasma proteins, which can be affected by conditions like polycythemia, anemia, and liver diseases. 2. Blood Vessel Diameter: ○ Larger diameters reduce resistance and increase flow (like drinking through a large straw). ○ Diameter changes due to neural and chemical signals affecting vasodilation and vasoconstriction. 3. Blood Vessel Length: ○ Longer vessels have higher resistance and lower flow due to more surface area causing friction. ○ Shorter vessels have lower resistance and higher flow. 4. Vascular Wall Properties: ○ Elastic walls lower resistance. ○ Contractile walls increase resistance. 5. Total Cross-Sectional Area: ○ Larger areas of blood vessels reduce resistance. ○ Small arteries and arterioles significantly affect flow due to their ability to narrow and expand. Types of Resistance Elastic Resistance: Due to the elasticity of large arteries, like the aorta, which helps maintain continuous blood flow and reduces heart workload. Peripheral Resistance: In smaller arteries and arterioles, changes in diameter greatly impact blood flow. Aging and Vascular Resistance As arteries age, their elasticity decreases, increasing resistance. This change affects the aorta significantly, impacting continuous blood flow and maintaining minimum arterial pressure during diastole. Blood flow in blood vessels The flow of blood in the blood vessels, like the flow of fluid in a tube, is determined by: 1. The pressure difference at the beginning (P1) and end (P2) of the vessel and (as it branches, the total cross-sectional area increases, the linear velocity decreases, the pressure decreases). Blood flows in the direction of the lowest pressure. 2. resistance (R), because the flow rate is calculated by Q = (P1 –P2) / R WHERE: Q -amount of fluid per unit of time P1-pressure at the beginning of the pipe P2-pressure at the end of the pipe R-total resistance From the formula: the greater the P drop (P1-P2) and the lower the resistance, the higher the blood flow volume velocity. In turn, the total resistance is affected by: Blood viscosity (usually constant, hematocrit dependent) Length of blood vessels (tubes) in the circulatory system (fixed in adults). Peripheral resistance -THE MOST VARIABLE! It changes physiologically due to changes in the diameter of the capillaries under the influence of nerve impulses and chemicals. Elastic resistance. In aorta and the large arteries that branch from it and are very elastic. Physiologically changes with increasing age. Blood vessel (tube) diameter – lumen 80. What are the main (5) differences between unconditioned and conditioned reflexes? Give examples of each and analyse them. Classification of reflexes 1. Inborn reflexes or unconditioned reflexes These reflexes are further divided: a) Autonomic – related to the regulation of internal organs b) Somatic – related to the regulation of skeletal muscle functions 2. Learned (acquired) reflexes or conditioned reflexes The unconditioned reflex is the innate reaction of the organism, which is the same among the members of the given species. They are characterized by a permanent and clear connection between action on the receptor and a certain response, ensuring that organisms adapt to stable living conditions. A conditioned reflex is a reaction that the body acquires during its life and responds to the stimulation of receptor. Conditioned reflexes are developed through the formation of temporary connections in the cerebral cortex and serve as mechanisms for adaption to the complex changing environmental conditions. Unconditioned reflexes: Innate adaptive responses, usually within species ○ Example: Suckling Reflex in Newborns ○ Description: Newborn mammals instinctively suckle when their mouth is placed near the mother's nipple.  ○ Analysis: This reflex ensures that the newborn receives the necessary nutrition immediately after birth, critical for survival. Stable adaptation reactions, as they persist throughout life, regardless of the frequency of use. ○ E: Patellar (Knee-Jerk) Reflex ○ Description: Tapping the patellar tendon causes the quadriceps muscle to contract, resulting in the leg kicking out. ○ Analysis: This reflex persists throughout life and remains consistent regardless of how frequently it is tested, helping maintain posture and balance. They are species specific reflexes because they are characteristic of all individuals of the same species ○ E: Startle Reflex in Humans ○ Description: A sudden loud noise causes an involuntary jump or startle response. ○ Analysis: This reflex is seen in all humans and serves as a protective mechanism, preparing the body for potential danger. They are realized through any part of the CNS ○ E: Blinking Reflex ○ Description: An object approaching the eye rapidly causes an involuntary blink. ○ Analysis: This reflex involves the brainstem and helps protect the eyes from potential harm. Only strictly defined reflex arc ○ E: Withdrawal Reflex ○ Description: Touching a hot object causes an immediate withdrawal of the hand. ○ Analysis: This reflex follows a well-defined pathway involving sensory neurons, interneurons in the spinal cord, and motor neurons, allowing for a quick response to prevent injury. Analysis of Examples Suckling Reflex in Newborns Innate and Adaptive: Ensures immediate access to nutrition. Species-Specific: Present in all mammalian newborns. Patellar (Knee-Jerk) Reflex Stable Adaptation: Remains consistent throughout life. CNS Involvement: Mediated by the spinal cord, demonstrating that reflexes can be processed without brain involvement. Startle Reflex in Humans Species-Specific: Seen universally in humans. Adaptive Response: Prepares the body for quick action in response to sudden threats. Blinking Reflex CNS Realization: Controlled by the brainstem, showing the involvement of various CNS parts in different reflexes. Protective Mechanism: Prevents potential damage to the eyes. Withdrawal Reflex Defined Reflex Arc: Involves a direct and specific neural pathway. Adaptive: Protects from harm by removing the body part from the source of pain quickly. Conditioned reflexes:  Adaptive responses during life. ○ Example: Salivating at the Sound of a Bell (Pavlov’s Dogs) ○ Description: Dogs learn to associate the sound of a bell with being fed, causing them to salivate when they hear the bell, even without seeing food. ○ Analysis: This response is not innate but developed through repeated association, illustrating how animals can adapt their behavior based on experiences. Labile because they last only as long as the conditions under which the reaction occurs exist. ○ Example: Fear of a Specific Sound After a Traumatic Event ○ Description: A person who experiences a car accident while hearing a specific song may feel fear whenever they hear that song afterward. If the song is no longer associated with traumatic events, the response may fade over time. ○ Analysis: This conditioned reflex persists only as long as the association remains strong and relevant, demonstrating its transient nature. A reflex usually has an individual nature, acquired through the individual’s experience ○ Example: Anxiety Before Public Speaking ○ Description: An individual who has had negative experiences with public speaking may develop anxiety when faced with similar situations. ○ Analysis: This reflex is unique to the individual based on personal experiences and does not necessarily apply to everyone. They are realized only through the highest parts of the CNS. ○ Example: Feeling Hungry at a Regular Mealtime ○ Description: A person accustomed to eating lunch at noon may feel hungry around that time, even if they have had a late breakfast. ○ Analysis: This conditioned response involves the cerebral cortex, which governs higher-order thinking and planning, rather than just basic reflexive actions. Reflex arcs can be different, even combined ○ Example: Student Stress Before Exams ○ Description: A student who has repeatedly experienced stress and anxiety during exams may start to feel stressed upon entering a classroom or seeing a textbook. ○ Analysis: This complex conditioned reflex involves multiple sensory inputs and associative pathways in the brain, showing how different reflex arcs can be combined to produce a specific response. Analysis of Examples Salivating at the Sound of a Bell (Pavlov’s Dogs) Adaptive Response: The dogs learn to anticipate food, an important survival adaptation. Experience-Based: Developed through repeated pairings of the bell with food. Fear of a Specific Sound After a Traumatic Event Labile Response: The fear response can diminish if the sound is no longer associated with traumatic experiences. Individual Nature: Unique to the person’s traumatic experience. Anxiety Before Public Speaking Experience-Based: Developed through negative experiences, and is unique to the individual. CNS Involvement: Involves higher brain functions like memory and emotion processing. Feeling Hungry at a Regular Mealtime  CNS Involvement: Managed by the cerebral cortex, which coordinates the body's response to time-based cues. Adaptive Response: Helps maintain regular eating habits for better health and energy management. Student Stress Before Exams Combined Reflex Arcs: Involves various inputs (visual, environmental) and associative pathways in the brain. Adaptive Response: Can motivate better preparation but also showcases the potential for maladaptive stress. 41. Ticket 81. What is blood and what are its functions? The composition of blood. The description of blood cells. ➔ Blood – body’s liquid tissue ➔ Composed of: ◆ Blood plasma (liquid part) ◆ Blood cells (red blood cells, white blood cells, platelets) Blood functions: WBC – defense function RBC – gas exchange, pH maintenance Platelets – blood clotting (defense function) Plasma – nutrient supply, regulation, transport, etc. ◆ Lymph – starts blindly in tissues, circulates parallel to blood vessels, go through lymph nodes (filters, takes up lymphocytes, immune substances), flows into the heart. ◆ Lymph does not contain RBC, so it is white ➔ Blood is a circulating tissue composed of plasma and cells. Blood circulates in arteries and veins, delivering oxygen and nutrients to cells and transporting metabolic waste products away from those cells. ➔ Blood, together with lymph and tissue fluid, makes up the body’s internal environment. ➔ ➔ Blood functions: ◆ Transport function (basically communication f.) – Respiratory gases (O2 and CO2) – respiratory function Biologically active compounds1 (BAC) – humoral regulation Ensuring metabolism – supply what is needed and take away the end products of metabolism2 ◆ Thermoregulatory function – blood transfers heat, equalizes the temperature between different organs.  ◆ Maintain homeostasis of the internal environment: relatively constant concentration of solutes, temperature and pH. All of these factors are essential for normal cell function. ◆ Protective function Blood contains antibodies, antitoxins and other substances, as well as immune cells and phagocytes, which provide humoral and cellular immunity The blood’s ability to clot reduces the chance of bleeding 82. What is saliva? What are its physiological roles? The regulation of secretion of saliva. Saliva Saliva is the first digestive juice. Saliva is produced by 3 major pairs of salivary glands: 1. Parotid gland Produces watery, protein rich saliva without mucus (serous salivary gland). In adult ruminants, the gland secretes continuously. 2. Submandibular gland Produces both watery and mucous saliva (serous mucous or mixed salivary gland). 3. Sublingual gland Produces mucous, viscous saliva (mucous salivary gland) Composition of saliva 98% water! Organic substances (main) are: ○ Enzymes – mainly amylase (ptyalin) (a lot in human, pig saliva, in small amount in ruminant and horse saliva), ○ Mucin - mucilaginous substances (mucus) ✓ Lysozyme – kills microorganisms ○ Albumins – protein (in horses saliva contains a lot of protein (latherin) – that’s why it foams). ○ Urea – (in ruminants in high amount, takes part in metabolism of nitrogen) ○ Innorganic substances, make up 2/3 of the dry matter. The main are chlorides, phosphates, carbonates (in ruminants NaHCO3 300-350 g/d!6) The amount of saliva The produced amount of saliva per day depends on the type of feed: in cows 50-100 liters in horses ~40 liters in pigs 15 liters in sheep 16 liters in humans 1-1.2 liters Excreted continuously, although unstimulated secretion (provided by the ENS Meissner's neural plexus) is ~4 X (up to 10X) less than that caused by autonomic parasympathetic n.s. Reaction of saliva Reaction of saliva (pH) is alkaline. In horses pH 7.6-7.8 In pigs pH 7.2-7.5  In dogs 7.5-7.8 (A.Ilgažs (2014.) 6,5) In ruminants pH 8-10, saliva is strongly alkaline, which ensures the biological digestion of food in the forestomachs, maintaining an optimal living environment for microorganisms. The meaning of saliva: Dissolves food, helps to determine the taste, swallow a bite. Rinses, cleans the mouth cavity. Facilitates sound modulation. Performs a protective function (lysozyme). Temperature regulation. Begins to break down carbohydrates. For ruminants keeps rumen pH in normal level. In ruminants urea in saliva is involved in the exchange of nitrogen. Characteristics and amount of saliva secretion in animals of different species In ruminants – saliva, first of all, plays a very important role in the rumination process. Saliva maintains a moist environment with a certain pH in the forestomachs. ○ Parotid salivary glands secrete continuously in ruminants. In the walls of the forestomachs, baroreceptors and chemoreceptors are irritated. ○ They are constantly irritated by the volatile fatty acids produced during the fermentation processes in the forestomachs. ○ From the receptors, the impulses go to the salivary center in the medulla oblongata and from there through the efferent nerves to the parotid salivary gland. ○ The secreted saliva neutralizes volatile fatty acids in the forestomachs. In ruminants, the submandibular and sublingual salivary glands secrete only during food intake and rumination. ○ The parotid salivary gland secretes poorly in newborn calves. Saliva is secreted mainly by the mucous sublingual and mixed submandibular salivary glands. ○ As the forestomachs develop and the calves begin to eat roughage, the parotid salivary gland begins to develop faster and secrete more strongly, and the saliva becomes more alkaline. ○ Consequently, the amount of saliva increases. Horses salivate mainly during eating, alternately on the side where the horse chews the feed. For example, it has been observed that saliva is sprayed at a distance of 25-30 cm with each away chewing movement from a fistula that has been operated in the excretory duct of the parotid salivary gland. In pigs and dogs, the large salivary glands also secrete only during eating. Small salivary glands secrete continuously. Regulation of saliva secretion Caused by unconditioned and conditioned irritants – hence both the unconditioned and conditioned reflexes. True secretory nerves are parasympathetic, causing a rich secretion of watery saliva. Sympathetic nerves cause weak secretion (secretion is blocked) - saliva is thick, mouth is dry. Unconditioned reflex is caused by direct (!) irritation In mouth cavity – especially the receptors on the tongue Strech- and chemical receptors in forestomachs.  Conditioned reflex can be caused by: smell, appearance, sound irritants related to the food, its preparation, giving, obtaining etc. if it has been fulfilled before! For example, a conditional reflex can be artificially developed in animals (Pavlov). Then the cortex of the large hemisphere and the higher subcortical centers also participate in the regulation of salivation. 42. Ticket 83. The physiological roles of water in the body. Functions: Forms the major part of body fluids, Acts as a solvent Acts as a medium for enzymatic reactions Thermoregulation Is a component of digestive juices Takes part in digestive processes Moisturizes air in the respiratory tract Moisturizes mucous membranes Acts as a lubricant for joints Acts as a shock absorber – protects organs (esp. brain and spinal cord) Fluid compartments: Equilibrium between compartments is maintained by osmoregulation Extracellular fluid (ECF): ○ Lies outside of cells ○ 20% of the total amount of fluid in the body ○ 5% is intravascular fluid, the rest is lymphatic fluid, the rest is interstitial fluid (between tissues and cells, brain fluid) Intracellular fluid (ICF) ○ Lies inside the cells (cytoplasm) ○ 40% of the total amount of fluid in the body Transcellular fluid (TCF) ○ Lies in serous cavities – eyes, joints etc. ○ Low amount of fluid in the body, variable In adult animals, around 65% of the total body mass is water; in newborns – 75-80% In brain 85% In heart 80%  In blood 83% In bones 20% Negative water balance (dehydration): From lack of drinking or because of diarrhea, vomiting etc. If the body loses 10-11% of water ➜ severe dehydration with organ function problems If it loses 20-30% ➜ death Checked with the skin fold test Positive water balance: Excess water is stored in the body (e.g., due to kidney or cardiac disease) Can result in edema – abnormal accumulation of interstitial fluid accompanied by swelling. Factors that result in edema: ○ an increase in capillary pressure, ○ increased capillary permeability, ○ a decrease in the concentration of plasma proteins, ○ obstruction of the lymphatic vessels 84. Describe the process of lipid absorption and transport in the body? Lipids are broken down to fatty acids & glycerol by lipases Fatty acids are absorbed together with bile acids In the intestinal mucosa, glycerol and fatty acids connect together again ➜ neutral lipids (triglycerides) ➜ clump together ➜ coated with phospholipids and a few proteins ➜ chylomicrons ~70% are absorbed in lymph ➜ vena cava cranialis ➜ lungs, where a part of them are oxidizes; CO2 + H2O + heat ➜ heats the air ~ 30% are absorbed in blood as low and high density lipoproteins (cholymicrons + proteins) ➜ go to liver where they take part in different synthesis processes ➜ either sterols are formed (cholesterol, phosphatides etc.), or they are oxidized 43. Ticket 85. The functions of the nephron loop. The role of kidneys in the regulation of internal osmotic pressure (neuro-humoral regulation). Countercurrent Mechanism ⎼ an active process in the nephron loops (loops of Henle) Responsible for the production of concentrated urine found in the collecting ducts Descending loop: highly permeable to water, but slightly permable to the sodium (Na) ions ➜ water reabsorption  As water travels from the ultrafiltrate back into the tissue fluid and further into the blood, the osmotic pressure of the urine in the descending loop increases (concentration) ➜ reabsorption of Na ions in the ascending loop is promoted Epithelial cells in the ascending loop are permeable to Na and Cl ions but not permeable to water The absorbed Na ions return to the intercellular fluid, creating high osmotic pressure, which in turn causes increased water reabsorption in the descending loop as the Na ions "attract" water. Both of these processes are closely connected. If the countercurrent mechanism in the nephron loop is “turned off”, urine concentration will not occur ➜ kidney failure The blood in the vasa recta (going next to the loop) gains NaCl and loses H20 as it descends into the renal medulla and loses NaCl and gains H20 as it ascends toward the renal cortex. This preserves the concentration gradient in the renal medulla. Neuro-humoral regulation of kidneys: Osmotic pressure regulation through osmoreceptors; Increase in the osmotic pressure irritates osmoreceptors in the blood vessel walls & hypothalamus (central receptors) ➜ message to the nucleus supraopticus of the hypothalamus ➜ increase of ADH ➜ enhanced water reabsorption in nephron tubules and diuresis (excretion of urine) decreases rapidly ➜ water is retained in the body ➜ blood osmotic pressure decreases Osmotic pressure regulation through blood vessel volume receptors: Increase in the amount of circulating blood irritates the volume receptors in the carotid sinus & blood vessel walls ➜ message to the nucleus supraopticus of the hypothalamus ➜ decrease of ADH ➜ increased urine excretion (diuresis) ➜ water is excreted from the body ➜ osmotic pressure in the blood increases ➜ amount of circulating blood decreases P.s. closely related to osmoreceptors 86. How is the nervous system classified/divided? Describe each part. Division of the nervous system: The nervous system as a whole is divided into two subdivisions: 1. Central nervous system (CNS) = the brain and spinal cord 2. Peripheral nervous system (PNS) = nerves that go to CNS (afferent) and from CNS to muscles and internal organs (efferent). PNS is further divided into: a. Somatic NS ⎼ innervates skeletal muscles (voluntary control of body movements) b. Autonomic NS ⎼ innervates internal organs, blood vessels etc. This part of NS provides metabolism in organs and function of these tissue. Autonomic NS is divided into: i. Sympathetic ⎼ main effects: narrows blood vessels (except coronary), increases blood pressure, increases and strengthens the heart rate, reduces the secretion of all digestive juices (saliva, bile, gastric juice, etc.), dilates pupils, decreases urine  excretion, increases the secretion of adrenal glands, promotes sweating, improves muscle trophic. ii. Parasympathetic ⎼ main effects: dilates blood vessels (except coronary), lowers blood pressure, slows the heart rate, intensifies the secretion of all digestive juices, narrows pupils and bronchial smooth muscle. Neuron classification by shape: 1. Unipolar neurons – have one process that includes both an axon and a dendrite. Exclusively sensory neurons with dendrites in the periphery where they detect stimuli (sensory neurons – pain, temperature, tactile, proprioceptive). 2. Bipolar neurons have two processes, an axon and a dendrite, that extend from each end of the cell body, opposite each other. Located mainly in the olfactory epithelium (where smell stimuli are sensed), and as a part of the retina of the eye 3. Multipolar neurons have more than two processes, an axon, and two or more dendrites ⎼ most CNS neurons 4. Pseudounipolar neurons ⎼ sensory neurons in the peripheral nervous system. Contains an axon split into two branches; one branch goes to the periphery and the other to the spinal cord. Classification of nerve fibers: 1. By function: ○ Somatic – innervate skeletal muscles ○ Autonomic – innervate internal organs and blood vessels ○ Secretory – innervate the glands and stimulate secretion ○ Sensory (afferent) – transmit impulses to the CNS ○ Motor (efferent) – carry impulses toward the body surface ○ Interneurons (association neurons) – any neurons between a sensory and a motor neuron 2. By structure: ○ Myelinated or unmyelinated ○ Myelin insulates the neuron and speeds up the passing of an impulse ○ Myelin is formed in the CNS by oligodendrocytes, and in the peripheral nervous system by Schwann cells 3. By type of synapse and neurotransmitter: ○ Adrenergic ⎼ neurotransmitter is either adrenaline/epinephrine, norepinephrine or dopamine ○ Cholinergic ⎼ neurotransmitter is acetylcholine ○ Peptidergic ⎼ neurotransmitter is a peptide hormone (somatostatins and others) 4. By diameter and conduction velocity: groups A, B, C ○ Group A: large myelinated fibers found in somatic nerves as sciatic and saphenous nerve Aα, (12-20 μm; 70-120 m/s), somatic motor, proprioception (afferent & efferent) Aβ (5-12 μm; 30-70 m/s), touch, pressure (afferent & efferent) Aϒ(3-6 μm; 15-30m/s), motor (efferent) Aδ (2-5 μm; 12-30 m/s), pain and temperature (afferent) ○ Group B: myelinated fibres found solely in preganglionic autonomic nerves Under 3μm, conduction velocity 3-15 m/s  ○ Group C: smallest, unmyelinated fibres of postganglionic synaptic nerves, mostly in visceral and cutaneous nerves, sense pain and temperature High threshold i.e., 30 folds of group A Diameter 0.3-1.3 μm, conduction velocity 0.5-2.3m/s ○ As diameter increases: Conduction velocity increases; Magnitude of electrical response increases; Threshold of excitation decreases; Duration of response decreases; Refractory period decreases 44. Ticket 87. What are the hormones produced by parathyroid glands? What are their physiological roles? Parathyroid glands ⎼ tiny, round structures usually embedded in the posterior surface of the thyroid gland. Only hormone produced is the parathyroid hormone or parathormone (PTH) Produced by chief cells (primary functional cells) Regulates blood calcium level by increasing it ⎼ the opposite effect is caused by calcitonin (thyrocalcitonin) which is produced by the thyroid glands ○ The level of Ca in blood is what regulates the release of the respective hormone ○ Both of these hormones work in coordination to keep calcium level within the necessary, species-specific limits ○ Both of these hormones also participate in the regulation of phosphorus level ○ Optimal Ca/P ratio in small animals 1:1 and large animals 2:1 Promotes Ca and P absorption in the gastrointestinal tract Promotes Ca reabsorption in the nephron tubules Inhibits P reabsorption in the nephron tubules Activates osteoclast activity that break down bone tissue ➜ Ca and P leave the bones Parathyroid glands are absolutely necessary for life-support: if they are removed, the animal dies of suffocation within 24h due to spasmodic contractions of the respiratory muscles ○ Ca levels crash ➜ muscles can't contract ➜ suffocation From protocol: Why Ca supplements should not be administered to cows prior to calving? ○ They will slow down/stop the natural Ca metabolism ➜ cow loses a lot of Ca during labour ➜ body can't supply more ➜ severe Ca deficiency Why do the parathyroid glands “fall asleep”? ○ Due to supplements that keep the Ca levels up  What can be the consequences? ○ It can lead to hypoparathyroidism that can cause tetanus, tachcyardia, GI stasis, low temperature, seizures, and coma ➜ death in a few hours When will the consequences be particularly pronounced? ○ After birth What is the diagnosis? ○ Milk fever 88. In what parts is the blood circulatory system divided? The functional description of those parts. How does the blood flow velocity change and how does the blood flow volume change in each of these parts? Why? Parts and functions: 1. The heart a. Function: the pump ➜ making blood flow through the circulatory system i. The pump function is ensured by successive contraction and relaxation of individual parts of the heart: 1. Atrial systole (contraction) ➜ "Suction pump" = blood is sucked from the veins into the heart 2. Ventricular systole ⎼ "pressure pump" = ejecting blood 3. Total diastole (relaxation) 2. Arteries a. Function: resistance blood vessels. Elastic layer with muscle tissue ➜ muscle contraction/relaxation changes the diameter of the vessel, which changes the resistance of the blood flow. 3. Capillaries a. Function: called metabolic blood vessels because they deliver blood close to tissues. Capillaries are the only place where substances are exchanged between the blood and the intercellular fluid. b. Thinnest walls and largest total cross-sectional area ➜ smallest linear blood flow velocity 4. Veins a. Function: capacitance/volume blood vessels ⎼ regulate blood flow to the heart. Vein walls are thinner than arteries and contain smooth muscle ➜ a large amount of blood can accumulate in the veins because their walls are easily stretched and can contract when emptying. Blood flow velocity: The linear velocity of blood flow is the distance traveled by one blood particle in one unit of time (usually 1min). It differs in different parts of the blood circulatory system and depends on the total cross-sectional area of the blood vessels. As the total cross-sectional area of the vessels increases, the velocity of flow decreases.  In large arteries linear velocity is highest, 0.1-0.2 m/s In arterioles 0.002 - 0.003 m/s In capillaries it is the slowest, near 0.0003 m/s (largest total cross-sectional area) ○ Gives time for exchange of gases and nutrients, In veins cross-section decreases and linear velocity increases to 0.001 - 0.05 m/s in large veins and to 0.1 - 0.15 in vena cava. Blood flow volume: Blood flow rate is the volume of blood flowing through the blood vessel lumen in a given period of time (usually 1min). The total volume is the same in different parts of the circulatory system, e.g. aorta = pulmonary artery and vena cava = lung veins This can be explained by the changes in velocity and cross-sectional area ⎼ compared to capillaries, large vessels have a faster flow but a smaller total cross-sectional area ➜ same amount passes in 1min Equal amount ensures that all tissues receive adequate oxygen and nutrients while waste products are efficiently removed (AI) The total volume depends on the stroke volume (SV) and heart rate ○ Stroke volume = amount of blood pumped out of each ventricle with each contraction Stroke volume can be affected by e.g. heart size, its contractility, duration of contraction, resistance and other factors Increased by: sympathetic stimulation, epinephrine and norepinephrine, high blood calcium level, thyroid hormones Decreased by: parasympathetic stimulation, acetylcholine, hypoxia, hyperkalemia 45. Ticket 89. The physiological functions of the skin. Skin as an excretory organ. The role of sweat glands, regulation of sweat excretion. Skin functions: Mechanically protects the organism from the influence of the external environment Determines the distribution of substances between the organism and the environment Protects against the UV radiation Bactericidal function Participates in body thermoregulation Receptor function Thermoregulation Exocrine glands – have ducts and secrete to the surface: examples of exocrine glands are: sebaceous and sweat glands (in the skin), salivary glands (oral) Type – tubular Secretion – sweat (99% water, 1% dry matter19) ◦ Two types (structure, functions, position, composition of secretion): 1. Atrichial (formerly Eccrine) – in the skin; functions: thermoregulator, excretory function (metabolic end products, water, minerals (see kidney functions), psychogenic. Cats and dogs have these sweat glands on their paw pads and noses. Sheep and cows have these glands on their noses and above their lips. 2. Epitrichial (formerly Apocrine) – in the area around the anus, also in the armpits; do not perform cooling function because they secrete oily secretion which does not evaporate easily; the function – to release pheromones after sexual maturity Sweat gland structural parts ◦ Secretory part (tubular, twisted into a ball, wrapped around by blood capillaries). It consists of spindle-shaped myoepithelial cells and two secretory cell types: Clear cells with plasmalemma ion pumps actively transport sodium to the lumen of the gland Dark cells are rich in secretory granules, containing glycoproteins (mucocytes) ◦ Excretory part (tubular, straight part) a) Cells of the basal layer of the dermis ensure the reabsorption of Na, K and Cl from sweat into the blood. The process is facilitated by aldosterone. b) The epidermal part opens to the surface of the skin, where sweat is also removed. 90. What forms the hypothalamo-hypophyseal system? Explain it, which endocrine organs are regulated by this system? The hypothalamus and pituitary gland are very closely interconnected Neural and humoral connection The hypothalamus secretes hormones which affect hormone synthesis in the pituitary  Tropic hormones synthesized by the pituitary affect endocrine organs throughout the body. The hypothalamo-hypophyseal system is connected through the bloodstream and nerves! ◦ There is a humoral connection between the hypothalamus and the adenohypophysis. Portal blood system (humoral) (hypothalamus→ adenohypophysis), it consists of primary and secondary capillary network. Blood flows in the direction from the hypothalamus to the adenohypophysis, so the biologically active substances -liberins and -statins secreted by the hypothalamus are transported to the adenohypophysis. They affect the production of –tropic hormones in the adenohypophysis. ◦ There is a neural connection between the hypothalamus and the neurohypophysis. It consists of hypothalamo-hypophyseal tract – a bundle of nerve fibers which: ▪ Starts from the hypothalamus n. supraopticus un n. paraventricularis ▪ and branches into neurohypophysis. The following move along this tract: ◦ Nerve impulses coming from different parts of nervous system ◦ Hormones in form of neurosecrete (axonal transport) produced by the hypothalamic nuclei and transported to the neurohypophysis: oxytocin and ADH. So the hypothalamus coordinates the neural and humoral regulation of physiological functions through the hypophysis Endocrine organs that are regulated by this system: Anterior Pituitary (Adenohypophysis):Hypothalamic-releasing hormones Posterior Pituitary (Neurohypophysis):Vasopressin (ADH), Oxytocin Thyroid Gland: hypothalamus secretes thyrotropin-releasing hormone (TRH)→TRH stimulates the anterior pituitary to release thyroid-stimulating hormone (TSH)→TSH, in turn, stimulates the thyroid gland to produce and release thyroid hormones (T3 and T4), which regulate metabolism and energy balance Adrenal Cortex: hypothalamus produces corticotropin-releasing hormone (CRH)→CRH stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH)→ACTH acts on the adrenal cortex, promoting the synthesis and release of glucocorticoids (e.g., cortisol) involved in stress response and metabolism. Adrenal cortex can produce androgens, glucocorticoids, mineralocorticoids Gonads (Ovaries and Testes): hypothalamus secretes gonadotropin-releasing hormone (GnRH)→GnRH stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH)→ FSH and LH regulate gamete production (sperm and ova) and sex hormone secretion (estrogen and testosterone) Growth Hormone (GH): hypothalamus releases growth hormone-releasing hormone (GHRH) and somatostatin→GHRH stimulates the anterior pituitary to release growth hormone (GH)→ which influences growth, cell division, and metabolism  46. Ticket 91. Composition of ultrafiltrate and urine. Ultrafiltrate: composition similar to that of plasma composition water, urea, glucose, salts, and other plasma solutes. Large molecules such as blood cells and large proteins are not filtered by the glomerulus since they don't pass through the epithelium Urine: wastes are eliminated from the body with the urine: urea, uric acid, creatinine, drugs, feed additives, pesticides 92. Types of digestion. Describe each. 1.Intracellular type. Evolutionary is the oldest. As the only type characteristic of unicellular and lower multicellular organisms that digest the food in so called digestive vacuole (+has remained in leukocytes but perform protective function). Highly developed animals also have intracellular digestion, for example, di- and tri- peptides can be transported to intestinal cells and digested till amino acids 2.Extracellular type. Is characteristic to highly developed animals in which digestion takes place in the cavities of the digestive tract. There are 2 types of extracellular digestion in the digestive tract: 2.1. cavity digestion, in which the digestive juices are mixed with food porridge (chyme5 ) in the stomach and intestines, where the enzymes perform their functions. 2.2. membranal digestion, which occurs mainly in the small intestine, where the enzymes are fixed on the microvilli (one layer of epithelial cells; the arterial and venous capillary and the lymphatic vessel). Enzymes act on already partially digested nutrients by breaking them down until the substances can be absorbed.  47. Ticket 93. How are blood types and the Rhesus factor determined in humans? Why do we determine blood types? What are requirements for donors (cats and dogs)? Based on the presence or absence of antibodies (agglutinins) in the blood plasma, as well as the presence or absence of inherited antigenic substances (agglutinogens) on the surface of red blood cells (RBCs). If the corresponding agglutinogen comes into contact with the corresponding agglutinin, erythrocyte agglutination occurs (RBC sticking together), so they are called an agglutination couple. In human and animal blood, there is no single agglutination couple of agglutinogen and agglutinin (in humans A and α, as well as B and β). Blood groups are usually named after the agglutinogen present on the surface of the erythrocyte Since humans can have agglutinogens A and B on the surface of RBCs, and agglutinins α and β in the blood plasma, 4 blood groups can be determined Determination of blood group: Lancet (scarifier), glass slide, ethanol, cotton wool, glass stick, mononuclear serums – coliclone anti A and anti B is needed Write the names of mononuclear serums anti-A and anti-B on a clean, dry glass slide and put one drop of each coliclone. Take a blood sample. The first blood drop is wiped with dry cotton wool. Take the second drop with one end of a glass stick and put it on a glass slide and mix with coliclone anti-A. Mononuclear serums should not mix with each other, so first the blood is mixed with anti-A and with the other end of the glass stick take the next blood drop and mix with anti-B. Look for agglutination (flakes are formed). If there is no agglutination in any drop, the examined person has I (0) blood group. If the agglutination reaction appears with anti-A, the person has blood group II (A), If the agglutination reaction appears with anti-B, III (B) blood group. If agglutination is observed in both mononuclear serum samples, then the person has IV (AB) blood group. Rhesus factor: Rhesus factor is another (third) agglutinogen on the surface of erythrocytes, which does not have an appropriate agglutinin in blood plasma. 85% of people have this agglutinogen (Rh(+) – rhesus positive), but 15% do not (Rh(-) – negative rhesus factor). In Rh(+) people, this agglutinogen is not considered as an antigen against which antibodies should be produced The Rhesus factor is important for people who have Rh(-), because if Rh agglutinogens enter the body of an Rh(-) person (blood transfusion, pregnancy, etc.), then the body synthesizes the so-called anti-Rhesus, which is a specific agglutinin. Repeated contact with Rh (+) blood causes an agglutination reaction, which is very dangerous, so knowing the Rhesus factor is very important. Determination of rhesus factor: Mononuclear serum anti-Rh and control serum, lancet, cotton wool, ethanol, glass slide, white plate labelled anti-Rh and control is needed On a clean and dry plate labeled anti-Rh and control add one drop of mononuclear serum on each side. Take a blood sample. The first blood drop is wiped with dry cotton wool. The second drop of blood (at least 4 times smaller than the drop of serum on the plate) is taken with one edge of the glass slide and mixed with serum anti-Rh. Serums should not mix with each other! With the other edge of the glass slide take the next blood drop and mix with the control serum. If agglutination is observed, then this person is Rh(+) – erythrocytes contain rhesus agglutinogen. If the agglutination reaction is not observed, then this person is Rh(-) – no rhesus agglutinogen in erythrocytes Note: There should be no agglutination in the control serum! If, however, agglutination is observed, then according to the described method, the Rh factor cannot be determined for this person, because his erythrocytes have tendency to stick together (agglutinate) Requirements for donors: Cats: 1 blood group system (considered the simplest blood group system), which includes 3 blood groups (A, B and AB). Cats do not have blood group 0, so there is no universal blood donor. If a cat receives a different blood group even once, a hemolytic transfusion reaction will occur, which can be fatal -should have never received a blood transfusion -Blood screening: Feline Leukemia virus, Feline Immunodeficiency virus -Up to date with vaccinations - Should be spayed or neutered -between 1 and 8 years old -fit and healthy Dogs: 8 blood groups The two main groups tested for are DEA 1 positive and DEA 1 negative. -Fit and healthy -Between 1 and 8 years old -Should be vaccinated or should have an annual titre test -Dogs with negative blood type are particularly valuable because their blood can be given to all dogs in emergencies 94. How happens food’s mechanical, chemical and biological digestion in the gastrointestinal tract? Mechanical food processing Motor function Performed by muscles of the digestive tract, food is: crushed (grained), dissolved, mixed with digestive juices and moved forward the digestive tract. Striated myocytes are only in 1/3 of esophagus and anal sphincter (what does it mean?) Striated myocytes – animal can control defecation, hold defecation! Smooth myocytes are located throughout the whole digestive tract – arranged in two directions as: circular muscle fibers and longitudinal muscle fibers. The myenteric (Auerbach’s) plexus, located between the inner and outer layers of the muscularis externa and the submucosal (Meissner’s) plexus, located in the submucosa of the enteric nervous system (ENS) are groups of ganglia that run throughout the entire gastrointestinal tract. Myenteric (Auerbach’s) plexus is mainly organized as a longitudinal chain of neurons. When stimulated, this plexus increases the tone of the gut as well as the velocity and intensity of its contractions. This plexus is concerned with motility throughout the whole gut. Inhibition of the myenteric system helps to relax the sphincters —the muscular rings that control the flow of digested food or food waste. The excitation of smooth myocytes is shallowly oscillating, it is provided by the Auerbach’s plexus, but is determined by special rhythm-transmitting cells Cajal cells - appear as slow waves of the membrane potential (± 5-15 mV); but contractions appear as peak-like waves (± 40 mV). Cajal cells→ Specialized cells known as interstitial cells of Cajal (ICC) are distributed in specific locations within the tunica muscularis of the gastrointestinal tract and serve as electrical pacemakers, active propagation pathways for slow waves, and mediators of enteric motor neurotransmission. Submucosal (Meissner’s) plexus is more involved with local conditions and controls local secretion and absorption, as well as local muscle movements. The mucosa and epithelial tissue associated with the submucosal plexus have sensory nerve endings that feed signals to both layers of the enteric plexus. These tissues also send information back to the sympathetic pre-vertebral ganglia, the spinal cord, and the brain stem. Chemical food processing Performed by enzymes, polymers in food are converted into monomers. As a result of the cleavage (splitting), the polymers lose their structure but retain their energy and plastic value. Enzymes act very specifically to break down food: ✓ Proteases – proteins till amino acids 3 ✓ Lipases – fats till glycerin and fatty acids ✓ Amylases – carbohydrates till monosaccharides Each digestive juice contains its own enzymes. Enzymes are divided into: Simple enzymes – made up of protein amino acids, e.g., pepsin, trypsin Compound enzymes – made of amino acids and nonprotein component – cofactor (inorganic ions or organic molecules – coenzymes2 ), furthermore: Protein determines the specificity of the enzyme – the ability to accelerate a certain chemical reaction, Cofactor – “helper molecule” that assists in biochemical transformations. Biological food processing Performs microflora3 and microfauna4. ❖ There are 3 main groups of bacteria in the forestomachs: ✓ Cellulolytic bacteria - optimal pH above 6.2 (break down cellulose) ✓ Amylolytic bacteria – pH above 5.4 (break down carbohydrates, starch) ✓ Bacteria that break down nitrogen compounds. ❖ Protozoa catch, digest bacteria and use them in the synthesis of proteins of their own body. Protozoa enter the abomasum in huge quantities and further into small intestine, where they are digested. 48. Ticket 95. Processes which happen in nephron ducts from ultrafiltrate till storing the urine in renal pelvis. Passive and active reabsorption. Threshold substances. Mechanism of urine formation !!! Urine is formed from blood plasma!!! All parts of nephron are involved in the formation of urine Nephrons carry out three basic physiologic processes that allow the kidneys to perform their homeostatic functions: filtration, reabsorption, secretion Neuro-humoral regulation of renal functions (glomerualr filtration rate)  Filtration processes – in the neural way Reabsorption processes – in the humoral way Secretion processes – self regulation Filtration The first process performed by the nephron is to filter the blood, a process known as glomerular filtration. From the glomerulus through the podocytes part of the blood plasma enters the Bowman’s capsule - «filters out» Filtration is a physical process This semipermeable biologic membrane does not allow the formed elements of blood and blood plasma proteins to go through it but allows some of the smaller substances— including water, electrolytes (such as sodium and potassium ions), acids and bases (such as hydrogen and bicarbonate ions), organic molecules, and metabolic wastes—to exit the blood and enter the glomerular capsule. The fluid and solutes that enter the capsular space of the nephron form the filtrate, also known as tubular fluid Filtration intensity Depends on: Blood pressure, if , then filtration...INCREASES Oncotic pressure, if , then... DECREASES Pressure in the nephron capsule itself, if , then... DECREASES Reabsorption Most reabsorption takes place in the proximal tubule and nephron loop. Some more precisely controlled reabsorption also occurs in the distal tubule and collecting ducts; this process allows the nephron to vary the amounts of different substances reabsorbed to maintain homeostasis as the needs of the body change. Substances are transported back to the blood from nephron tubules. It is both physical and physiological process. It is both passive (diffusion and osmosis) And active process (performs epithelial cells of the nephron tubules, by using energy) Are reabsorbed: Water (85%) (which is required for maintenance of the body’s fluid homeostasis) Electrolytes (including sodium, chloride, potassium, sulfate, and phosphate ions, (electrolyte homeostasis)) Many of the bicarbonate ions, critical for acid-base homeostasis Nearly 100% of nutrients such as glucose, amino acids, and other organic substances (e.g., lactic acid, water-soluble vitamins). Tubular Reabsorption In tubular reabsorption, substances must pass from the filtrate in the lumen (inside) of the tubule across or between the tubule cells, into the interstitial fluid, and finally across or between the endothelial cells of the peritubular capillaries to re-enter the blood. In tubular secretion, substances move in the opposite direction. During tubular secretion substances are moved from the peritubular capillary blood into the filtrate to eventually be excreted Countercurrent Mechanism An active process occurring in the loops of Henle in the kidneys, which is responsible for the production of concentrated urine in the collecting ducts of the nephrons. the descending loop is highly permeable to water, but slightly permable to the Na ions. Water reabsorption occurs. As water travels from the ultrafiltrate back into the tissue fluid and further into the blood, the osmotic pressure of the urine in the descending loop increases (happens its concentration) this promotes the reabsorption of Na ions in the ascending loop. Epithelial cells in the ascending loop are permeable to Na and Cl ions but not permeable to water. The absorbed Na ions return to the intercellular fluid, creating high osmotic pressure, which in turn causes increased water reabsorption in the descending loop as the Na ions «attract» water. Both of these processes are closely connected. If the countercurrent mechanism in the nephron loop is “turned off”, urine concentration will not occur! (Kidney failure). 1. When filtrate enters the cortical collecting duct in the renal medulla, there is no osmotic gradient between the filtrate and the interstitial fluid, so no water is reabsorbed. 2. In the presence of ADH, the concentrated medullary interstitial fluid creates a gradient for water reabsorption from the filtrate in the medullary collecting duct. 3. Deeper into the medulla, interstitial fluid is more concentrated, so water reabsorption continues from the medullary collecting duct. 4. Concentrated urine is produced When the filtrate reaches the end of the papillary duct, it is urine. Secretion is an active physiological process in which epithelial cells of the tubules transfer substances from the blood to the urine, which must be eliminated from the body. For example, urea, uric acid, K+ ions, drugs, etc. Secretion happens all along the tubule, although different substances may be secreted more in one area than another. Tubular secretion helps to maintain electrolyte and acid-base homeostasis. !!! IN THE RESULT OF FILTRATION, REABSORPTION AND SECRETION URINE IS FORMED WHICH IS THEN EXCRETED FROM THE BODY. Reabsorption threshold The renal threshold is the concentration of a substance in the blood above which the kidneys begin to excrete it into the urine. When the renal threshold is exceeded, the reabsorption of the substance in the proximal convoluted tubule is incomplete; so some of the substance remains in the urine. Threshold substances are substances that have so-called “threshold” – it is the maximum amount of a substance in the blood at which the substance can be completely reabsorbed back into the bloodsteam from the ultrafiltrate. For example, glucose. Threshold-free substances are those that are never reabsorbed back into the bloodstream in nephron tubules, regardless of their concentration in the blood. For example, creatinine 96. When and why occurs ictus cordis and heart sounds during the cardiac cycle? Ictus cordis: Is the heart touching the chest wall is called the heart apex beat It corresponds to the moment when the left ventricle contracts and pushes blood into the aorta. First heart sound S1: “Lub”-sound During ventricular systole Results from closure of the AV valves Second heart sound S2: “Dub”-sound During the ventricular diastole It results from the closure of the semilunar valves (aortic and pulmonary valves) The other heart sounds S3 and S4 are less audible and usually associated with specific cardiac conditions 49. Ticket 97. What is the intrinsic regulation of cardiac functions? What parameters regulating the action of the heart can be changed? Regulation of cardiac functions 1. Myogenic regulation mechanism: - Regulates heart muscle contraction - Velocity - Force - Frequency - Relaxation -Velocity - Degree Starling's law: an increase in myocardial stretch increases the force of contraction of the heart. When the sympathetic nervous system is activated, e.g., with increasing physical or emotional load, the tone of the volume blood vessels (i.e. veins) increases and increases the blood supply to the heart. LAW: The force of contraction is proportional to the initial length of the cardiac muscle within physiological limits (basically, the more blood the heart receives the harder it pumps to accommodate) (Starling’s law, the law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction (the end diastolic volume), when all other factors remain constant) Law: the more heart chambers are filled with blood during diastole, the greater force of contraction they develop during systole. This prevents ventricles from dilation allowing them to eject all the blood 2. Humoral regulation mechanism Regulates o Heart rate o Contractile force of the heart muscle - Epinephrine ↑ - Acetylcholine ↓ - Electrolytes: Ca ↑ K↓ - Thyroxin (T4)↑ - Triiodothyronine (T3)↑ 3. Neural regulation mechanism 3.1. Intracardiac regulation 3.2. Extracardiac regulation Regulate heart muscles contraction o Velocity o Force o Excitability - Parasympathetic n.s. ↓ - Sympathetic n.s. ↑ 3.1.Intracardiac regulation This regulation is provided by intracardiac autoregulatory mechanisms. Also seen in isolated - deinerved hearts. This regulation is made up of ganglia and the nerve fibers that go from them to the myocardium and all the heart muscle formations. Happens slower and within a narrower range. There are 2 mechanisms of intracardiac regulation: Adrenergic – it is more sensitive, works even at a slight stretch of the heart walls. Epinephrine and norepinephrine are released at the ends of adrenergic fibers. Heart activity is accelerated, intensified (it works faster, with increased rate). Cholinergic – works at high wall stretch. Acetylcholine is released at the fiber ends. Slows down and weakens heartbeat. 3.2. Extracardiac regulation Receptors that regulate the heartbeat:  1. Baroreceptors that sense changes in pressure or stretching, are localized mainly at the 'entrance' of the heart, the ventricles, and the area of the aortic arch and the pulmonary trunk (the 'exit' of the heart). 2. The chemical receptors perceive changes in the amount of blood gases, especially an increase in the concentration of carbon dioxide. Located in both the aortic arch and the carotid sinus. Afferent nerve fibers transmit impulses to the CNS to Heart regulation center in the medulla oblongata Efferent nerve fibers in somatic nervous system: 1. parasympathetic (acetylcholine, cholinoreceptors) 2. sympathetic (epinephrine, adrenoceptors) 98. What is the physiological meaning of components of saliva? The connection between secretion of saliva and food intake? Particularities of composition and excretion of saliva in ruminants? 98% water! Organic substances (main) are: Enzymes – mainly amylase (ptyalin) (a lot in human, pig saliva, in small amount in ruminant and horse saliva), Mucin - mucilaginous substances (mucus) Lysozyme – kills microorganisms Albumins – protein (in horses……………….). Urea – (in ruminants in high amount, takes part ir metabolism of nitrogen) Innorganic substances, make up 2/3 of the dry matter. The main are chlorides, phosphates, carbonates. (in ruminants NaHCO3 300-350 g/d!) Dissolves food, helps to determine the taste, swallow a bite. Rinses, cleans the mouth cavity. Facilitates sound modulation. Performs a protective function (lysozyme). Temperature regulation. Begins to to break down carbohydrates. For ruminants keeps rumen pH in normal level. In ruminants urea in saliva is involved in the exchange of nitrogen. Regulation of saliva secretion Caused by unconditioned and conditioned irritants – hence both the unconditioned and conditioned reflexes. True secretory nerves are parasympathetic, causing rich secretion of watery saliva. Sympathetic nerves cause weak secretion (secretion is blocked)- saliva is thick, mouth is dry. Unconditioned reflex is caused by direct (!) irritantion  In mouth cavity – especially the receptors on the tongue Strech- and chemical receptors in forestomachs. Conditioned reflex can be caused by: smell, appearance, sound irritants related to the food, its preparation, giving, obtaining etc. if it has been fullfilled before! For example, a conditional reflex can be artificially developed in animals (Pavlov). Then the cortex of the large hemisphere and the higher subcortical centers also participate in the regulation of salivation. RUMINANTS The food remains in the rumen as long as it reaches a certain liquid consistency due to digestion and mixing with saliva. It is the saliva that provides optimal moisture and pH. Food stays in the rumen for 70-90h. The normal pH (6.5-7.4) in forestomachs contents remains constant because: Volatile fatty acids are intensively absorbed through the walls of the forestomachs The contents of the forestomachs is continuously neutralized by saliva Starch digestive amylolytic bacteria are less sensitive to changes of rumen pH. If the amount of grain in the animal feed is increased, the pH of the rumen decreases and it becomes acidic. Why? 1. It takes less time to eat and digest grain feed, so less saliva is excreted 2. Grain feed is fermented faster and more volatile fatty acids are formed, which can lead to faster rumen acidosis 3. Concentrated feed and grain meal do not cause as intense production of saliva as roughage 50. Ticket 99. The ways of food assessment in the mouth cavity? Food uptake, chewing, swallowing, rumination, the regulation of these processes. Mouth cavity is the beginning of the digestive tract. Here happens: Food sorting. Initiation of reflexes – because there are located very important reflexogenic zones (a lot of chemical-, tactile-, thermo-, pain-, taste receptors). Are initiated: 1. Motor reflexes – milk suckling, swallowing, chewing, spitting, motility of digestive tract. For example. The center of swallowing is located in the medulla oblongata. Without food we cannot perform swallowing movement because receptors are not irritated. The signals do not travel through the afferent nerves to the swallowing center and from there through the efferent nerves excitation does not reach the muscles involved in the act of swallowing. 2. Secretory reflexes – induce the excretion of saliva, gastric acid, pancreatic juices, bile. Digestion in the mouth cavity consists of 3 stages: 1. Food intake. 2.Chewing. 3.Swallowing. 100. The physiological roles of calcium in the body. Consequences of calcium deficiency. Ca (calcium) The most abundant mineral in the animal body. It is present in the body mainly in bone tissue (up to 99%). Quite a lot in the teeth too. During the second half of pregnancy and lactation Ca should be taken more. It is especially important to take Ca in sufficient amounts for growing organisms as well as for birds during intensive laying period. Functions: ○ In the formation of bones and cartilage ○ For blood clotting ○ As an activator for enzymes, e.g., pancreatic lipase, cholinesterase ○ For muscle contractions ○ For transmission of nerve impulses ○ Reduces nervous system and muscle excitability ○ In the permeability of cell membranes - absorption of nutrients into cells ○ Important in the absorption of vitamin B12 from the gastrointestinal tract ○ Enhances the phagocytic function of leukocytes ○ The body's resistance to various toxins and poisons increases The deficiency causes: ○ Increase in muscle and nerve excitability ○ Cramps ○ Bone deformations (in young animals – incomplete bone formation (rickets), in adult animals – bones weak and easily broken (osteomalacia) ○ The signs of deficiency: Curved legs Rachitis Enlarged joints Osteoporosis Thin egg shell Milk fever Ca toxicity: ○ Excessive Ca feeding can interfere with the absorption of minerals (especially zinc). ○ Excess dietary Ca is not usually associated with specific toxicity. Ca sources: ○ Milk ○ Soy ○ dark leafy greens ○ Broccoli ○ Almonds  ○ Grains are poor sources of calcium and animals fed high‐grain diets are at risk of becoming calcium deficient. Forages are better sources of calcium, with legumes being especially high in calcium. ○ Unfortunately, forage calcium availability can be low due to the presence of oxalates that make the calcium insoluble. milk fever (parturient paresis) ○ 51. Ticket 101. Shortly describe digestion processes in stomach: the composition of gastric juice, properties, action; regulation of secretion. 1) is a reservoir in which food stays for 0.5-3h; 2) chemical processing of feed takes place (with enzymes and HCl) 3) incretory function, because of the release of intestinal hormones (e.g. gastrin7 , bombesin8 , histamine9 , somatostatin10, serotonin11) in the blood 4) absorption function but weak (drugs, alcohol) In monogastric animals stomach has only one compartment in polygastric (multi-chambered) – 3 forestomachs and one “real” stomach. Gastric juice: Properties: colorless, clear  - dogs, pigs, humans : pH 1.0-2.5 - ruminants pH 2.2-2.8, in calves more acidic – 1.6) The main components of gastric juice: ❖ ENZYMES: * Gastric proteases: Pepsins – formed from pepsinogens, which are converted to pepsin by gastric HCl. Act in an acidic environment (pH60%) 2. Liver (~30%) 3. Gastrointestinal tract and other organs (~10%) Additional heat is produced by:  Activity of skeletal muscles Muscle tone Amount of fat In newborns so called brown fat Heat loss (physical thermoregulation): Evaporation Convection Radiation Conduction Heat loss through convection, when the body heats air and water: When air or water in contact with the skin is heated, it flows away. It takes more time for water to heat up, which means that animals that live in water lose more heat than animals that live on land. Heat loss by conduction is observed when the body is in contact with a colder surface Heat loss by radiation, when cooler objects absorb radiation produced by the body. All solid objects emit invisible electromagnetic radiation. Warmer objects emit more radiation than cooler objects Heat loss through evaporation can be observed when water in sweat, saliva and respiratory secretions is transformed in water vapor. Evaporation of 1 L of water requires 580kcal Temperature-sensitive receptors are localized in the CNS, skin and some internal organs: CNS – in hypothalamus In the skin, most thermoreceptors respond to cold In the internal organs, e.g., when you drink a large amount of cold water, the cold receptors in the gastrointestinal tract react to it. Since body tissues are poor conductors, heat is transferred most effectively by blood Because heat is mainly produced in the muscles of the limbs and in the liver and is eliminated through the skin and the respiratory tract, it is very important to transfer heat throughout the body. 110. What forms oncotic and osmotic pressure of blood plasma? What is the meaning of these pressures? Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins, pull water into the circulatory system Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. Functions of blood plasma proteins Create oncotic pressure in the blood plasma, which ensures normal exchange of water and salts in the capillaries. (eg., mechanism of edema) Protective role- especially for globulins. Help to keep blood pH relatively constant. Plasma proteins transport various substances in the blood. The only protein reserve in the body!