Module 3: Homeostasis Flashcards
Digestive Physiology: What is toxoplasma and what does it affect? State an example.
Toxoplasma is a parasitic protist that is able to affect any homeotherm. It can be found in mice by reducing gene factors for the hormone vasopressin. Vasopressin controls the amygdala in the brain (registering responses).
Digestive Physiology: What are the 4 processes in mechanical digestion?
Ingestion, digestion, absorption, and elimination.
Digestive Physiology: When would animals use endosymbiotic bacteria?
When a lack of digestive tract is present, the endosymbiotic bacteria aids with converting organic chemical energy into usable forms. Or by processing the nutrients directly in a rich environment.
Digestive Physiology: 2 examples of animals that use endosymbiotic bacteria in digestion.
- Tapeworms lack a gut, hence will move along the individual’s gut and consume their nutrients along the intestine.
- Rifitia (vent worms), have no digestive tract, no anus, and no mouth. They will harbor a bag of bacteria and treat it as a farm through their red gills to help convert organic chemical energy to usable energy (carbon-based nutrients).
Digestive Physiology: What is cellulose and why can it not be digested?
Cellulose is a glucose polymer that plants use for their structure. Most animals cannot digest glucose due to lacking cellulase, the enzyme that breaks down the glucose polymer.
Digestive Physiology: What enzyme is able to break down bacteria into food?
Lysozyme
Digestive Physiology: How do termites and rotifers interpret cellulase?
Termites and rotifers do not have cellulase (an enzyme for breaking down cellulose). The incorporation of a cellulase gene into an organism’s own genes occurs through gene transfer facilitated by endosymbiotic microtubules.
Gut Microbiome: What is the role of light junctions in a healthy gut and how are they connected?
Light junctions are formed by the epithelial cells which are connected by proteins. Their role is to help prevent leakage in the gut between cells in the extracellular fluid.
Gut Microbiome: How is a healthy ecosystem maintained in the gut?
There is a protective layer of mucus where the gut balances out the microtubes. This allows the bacteria to use nutrients to be converted into short fatty acids. Therefore the metabolites cross the cell barrier and are responsible for signaling the molecules in the microbiome status.
Gut Microbiome: What happens if the gut is imbalanced?
A maladatpive method will happen. Occurs by stopping the mucus layer from producing and depriving.
Gut Microbiome: In extreme cases of an imbalanced gut, what will happen?
Breaking of cell-to-cell connections can lead to cellular damage and allow entry of foreign particles into the body through the epithelium, leading to local inflammation that can impact the immune response.
Gut Complexity: Give an example of an animal that consists of a complex gut process.
The hydra begins with the food being digested in a central cavity that is surrounded by the tentacles, which also act as the hydra’s mouth. The digestive enzymes are secreted into this cavity and break down the food. The nutrients are then absorbed by the cells lining the cavity, and the waste is expelled through the same opening where the food was ingested. Once the digestion is complete, the hydra will continue to look for its next meal by extending its tentacles and scanning the surrounding water for any potential prey.
Fermentation Chambers: What is the oldest known organism with a unidirectional gut, and how does this specialized digestive system allow for different degrees of digestion through regional specialization, starting from the mouth and moving anteriorly through the linear gut to the anus? What is the role of pH?
The oldest organism is known as the Cloudina. Digestion will occur through regional specialization beginning at the mouth and going through the linear gut moving anteriorly. At the anterior end, the food breaks down by using teeth, beaks, tongues, and muscles. pH is significant in stomach acid by aiding the process of breaking down macromolecules for the basic gut.
Regionalization: What is an example of a specialized compartment and explain how it works.
Ruminants, such as cows, have a specialized compartment in their anterior region that helps break down food. The cow chews small amounts of food, which is then sent to chambers where cellulose helps break it down into a mushy pulp. The cow regurgitates and continues to chew and swallow the small pieces of food, which enters an acidic chamber for further digestion.
Surface Area: How is carbohydrate digested in the gut?
Carbohydrate is digested in a specific location within the gut due to the cells in that region being able to secrete enzymes that can break them down. Some breakdown of carbohydrates occurs in the mouth, which signals the body that glucose is on its way. However, not much happens to carbohydrates in an acidic stomach. Once in the small intestine, hydrolytic enzymes called saccharides break down complex carbohydrates into smaller and smaller units.
Cellular Specialization: How does surface area affect nutrient uptake in animals?
The surface area in the gut of animals is crucial for the efficient absorption and transportation of nutrients. Most animals have a compressed gut that creates circular folds and villi on the surface, which have many cells, and those involved in absorption have their own cellular extensions called microvilli. Underneath the villi are vessels that collect material from the gut and deliver it to the right part of the body. Nutrients move into the capillary beds or the extracellular fluid of the villi, which gets collected by the lymph vessels
Appetite: How do hormones regulate hunger in animals?
Various hormones regulate hunger in animals by signaling the brain about the state of the body. Leptin is released by adipose tissue when it’s full, signaling contentment and inhibiting hunger. Peptide YY is released by the gut when the colon is full, sending a satiety message to the brain. Insulin is secreted by the pancreas when glucose levels are high, telling the brain that the animal is content. Ghrelin is released by an empty stomach, stimulating the appetite. All of these signals converge on the hypothalamus, where a decision is made whether to send a signal to the animal’s behavioral centers that it is hungry.
Matching Feeding To Energetic Needs: Discuss how animals regulate their hunger and mention examples.
Appetite is dependent on feeding strategies and timelines, therefore varying amongst different species. For example, Barnacles, filter-feed all the time and don’t need to think about hunger. Or bears override their hunger centers and put themselves into a metabolic arrest for months without eating.
Note, Large predators go through cycles of feast and famine, where they endure extended periods without food and then consume large amounts during gorging periods.
Integrating Tissue Function with Homeostasis: What is an example of how the control of appetite needs to be flexible in animals that migrate?
The control of appetite needs to be flexible in migrating animals. For instance, some shorebirds will overeat and become overweight in preparation for their migration. Hummingbirds will double their weight by putting on fat before a long flight without feeding.
Osmoregulation: What is osmoregulation?
Osmoregulation is the process by which living organisms regulate the concentration of water and dissolved substances, such as salts and minerals, within their bodies. This process helps to maintain the proper balance of fluids and solutes in the body and is crucial for the survival of organisms in different environments.
Osmolarity-Related Terminology: What is the correlation between osmosis and molarity? Include examples of conversions.
Molarity: the number of moles of glucose per L solution.
The combination of molarity and osmosis creates osmolarity, which is molarity that lumps all the different solutes together.
1 M glucose has an osmolarity of 1 OsM.
1 M NaCl has an osmolarity of 2 OsM.
There is a difference between the conversions due to not all the NaCl dissociated into the ions.
Osmotic Pressure: What is osmotic pressure and how does it affect the movement of water between compartments separated by an osmotic gradient?
Osmotic pressure is the force that drives the movement of water from a region of lower solute concentration to a region of higher solute concentration. The movement of water will continue until the osmotic pressure on both sides is equal, which is when the movement will stop.
Osmolarity vs. Tonicity: What is the difference between osmolarity and tonicity, and how do they relate to a cell’s volume?
The difference between osmolarity and tonicity is that osmolarity is a property of a solution that is defined in units of osmolarity, while tonicity refers to how the solution affects a cell’s volume. A hypotonic solution causes a cell to swell, while a hypertonic solution causes a cell to shrink.
Osmolarity vs. Tonicity: What is the importance of osmoregulation?
Osmoregulation is important for animals to control ion and water movement in and out of the extracellular fluid (ECF) to maintain the proper osmolarity and ensure the health of its cells. Changes in ECF osmolarity can cause cell damage and loss of integrity.
Aquatic Environments: What is the relationship between aquatic animals and osmotic challenges, and how do different animals cope with changes in osmolarity in their environment?
Aquatic animals face diverse osmotic challenges due to varying osmolarity in their habitats. Intertidal animals, such as rock gunnels, maintain a constant internal osmolarity to tolerate rapid changes, which is known as osmoregulation. Blue mussels and little skates change their internal osmolarity to match the external environment, which is called osmoconformity.
Osmoregulators vs. Osmoconformers: What is the difference between an osmoregulator and an osmoconformer in animals?
Animals that are able to maintain a constant internal osmolarity despite changes in external osmolarity are osmoregulators. Those that permit their internal osmolarity to change are osmoconformers.
Tolerance of osmotic Challenges: What do the terms euryhaline and stenohaline mean in the context of animal osmoregulation?
Animals that can tolerate wide ranges in external osmolarity are called euryhaline, while those that live in a narrow range of salts are called stenohaline. These terms describe an animal’s ability to tolerate changes in external salt concentrations.
Transport Epithelia: 4 Key Factors of transport epithelia.
- Transport epithelia are tissues that move ions in and out of the body.
- Examples of transport epithelia include gills, lungs, skin, kidney, and intestine.
- Transport epithelia have 4 main features: different transporters on the inner and outer membranes, tight connections between cells, diverse cell types, and abundant mitochondria.
- Ion movement requires energy, so transport epithelial cells usually have abundant mitochondria for the aerobic production of ATP.
Specialized Tissues and Organs (Oldest Version): Explain the evolution of osmoregulatory tissue.
Flame cells are the oldest version of dedicated osmoregulatory tissues found in flatworms. The system consists of one cell that makes a tubule and another that creates a current to bring fluids into the tubule, which then gets collected and excreted from the body. Earthworms have a more complex version, with many cells joined together to draw fluids from the interstitial fluid into the tubule and excrete them through a hole in the body wall. Similar to the function of the kidney.
Specialized Tissues and Organs (Malpighian Tubules): What are Malpighian tubules in insects, and how do they help retain water in the body? How do mosquitoes use these tubules to compress their blood meal?
Insects, which colonized land early on, use Malpighian tubules to collect ions and excrete them via the gut. They help retain water in the body. Mosquitoes excrete water while feeding on blood to compress the meal into a concentrated protein meal.
Vertebrate Kidney - Structure, and Function: What is the structure and function of the nephron in the vertebrate kidney?
The nephron is the functional unit of the vertebrate kidney. It consists of two parts: the tubule and the glomerulus. Blood vessels enter the mouth of the kidney tubule (Bowman’s capsule) at the glomerulus, and low molecular weight solutes and fluid leave the blood through filtration. The fluid then moves through the tubule and is modified by transport epithelia that transport specific molecules in specific regions, reclaiming useful molecules from the urine and releasing them into the interstitial fluid. The urine is collected by the peritubular capillaries, which are responsible for maintaining an osmotic gradient that is essential for making concentrated urine. The fluid is carried through the proximal tubule, loop of Henle, distal tubule, and collecting ducts, which then empty into the ureter and eventually the urinary bladder.
Mammalian Kidney: What is the function of the proximal tubule in the nephron?
The proximal tubule modifies the urine by recovering valuable ions and excreting drugs and excess water-soluble vitamins. In the descending limb of the loop of Henle, aquaporins are the only transporters of importance for excretion, which increase the urine’s osmolarity. As the tubule returns to the surface, cells no longer make aquaporins and instead make the transporters needed to recover NaCl, decreasing the urine’s osmolarity but keeping the volume constant. The distal tubule is where the fine-tuning of the urine occurs, and is the target of various hormones that govern urine production.
Loop Henle: Describe the kidney.
The arrangement of multiple tubules in densely packed space within the kidney, beginning in the outer layer or cortex and looping down into the inner medulla and back up to the cortex. The collecting ducts of the tubules empty into a cavity in the kidney, which in turn empties into the ureter that carries urine from the kidney to the urinary bladder. The length of the loop of Henle in mammalian kidneys varies based on the need for water conservation, with longer loops allowing for the formation of concentrated urine.
Regulation of Water Balance: What is the role of ADH in the regulation of water balance in the body?
The hypothalamus detects high osmolarity in the blood and secretes the hormone ADH or antidiuretic hormone. ADH travels to the kidney where it increases the ability of the collecting duct to recover water, reducing urine volume. ADH also sends signals to the thirst centers to alter behavior to increase water consumption. This process is turned off by negative feedback when the combination of water recovery and drinking resets osmolarity.
ADH and Aquaporin - Localizing in the Collecting Duct: What hormone is secreted by the posterior pituitary in response to osmosensing and how does it signal the recovery of water in the kidneys?
The hormone is called vasopressin or antidiuretic hormone (ADH). Its receptor is on the cell membrane and triggers the activation of cAMP production and protein kinase A activity, leading to the movement of vesicles containing aquaporins to the cell membrane for facilitated diffusion of water.
Renin-Angiotensin-Aldosterone System (RAAS): What is the RAAs pathway and how does it respond to reduced blood pressure?
The RAAs pathway is a regulatory pathway that responds to reduced blood pressure caused by dehydration or blood loss. When vessels going into the glomerulus sense low blood pressure or volume, they release the enzyme renin, which activates the hormone angiotensin, produced by the liver. Angiotensin II triggers the release of aldosterone, which targets the kidney to increase the recovery of water and Na, increasing blood volume and pressure.
Evolutionary Origins of Cardiorespiratory Systems: What is the significance of having three embryonic cell layers in triploblasts?
The formation of three embryonic cell layers in triploblasts created the opportunity to make more specialized tissues, including those of the cardiorespiratory systems. This allowed for the evolution of more complex organisms with the ability to control the movement of fluids and gases to support their metabolic rates.
Vessels and Pumps - Arterial and Venous Vessels: What is the main reason why the outer layer and smooth muscle layer of an artery is thicker compared to a vein?
The outer layer and smooth muscle layer of an artery are thicker due to arteries have to cope with higher blood pressure without stretching too much.
Vessels and Pumps - Capillaries: What are sphincters in relation to capillaries?
Sphincters are muscle-like cells that control the diameter of capillaries, which can open and close as needed to control where blood flows.
Vessels and Capillaries - Interstitial Fluid: What is the function of the basal lamina layer in the context of the intestinal epithelium and capillary endothelium?
The basal lamina layer serves as a connective tissue that is produced at the base of both the intestinal cells and capillary endothelium, preventing leakage between the cells. It also forms a mesh that allows interstitial fluid to leak between and across it, which is contiguous with the fluid that the blood vessel runs through.
Vessels and Pumps - Regulating Flow: What is the role of endothelial cells in capillaries?
The endothelial cells in capillaries form the innermost layer of the vessel wall and are responsible for the exchange of gases, nutrients, and waste products between the blood and the surrounding tissue. These cells are very thin to allow for efficient diffusion, and their permeability can be regulated to control the flow of substances in and out of the bloodstream.
Vessels and Pumps - Regulating Flow: What are the two key features of capillaries in terms of their arrangement and relationship to surrounding tissues?
- The presence of sphincters, which are muscle-like cells that control the diameter of the vessels and can open and close as needed to control blood flow.
- Their relationship to surrounding tissues, where the capillary bed is perfusing the tissue with cells running through the gaps between the capillaries, and communication between the capillary and tissue cells occurs through the interstitial fluid.
Vessels and Pumps - Capillaries and Lymphatics: What are the lymph vessels responsible for?
The lymph vessels collect fluids, debris, and even cells that have leaked out of capillary beds and bring them back to lymph nodes for cleaning up.
Vessels and Pumps - Capillaries and Lymphatics: What is the purpose of the second set of vessels that run through the interstitial fluid?
The second set of vessels, which are the lymph vessels, collect materials that have leaked out of capillary beds, such as fluids, debris, and cells, and bring them back to lymph nodes for cleaning up.
Vessels and Pumps - Capillaries and Lymphatics: What is the role of lymph nodes in the process of collecting leaked materials?
The lymph nodes are responsible for cleaning up the materials that are collected by the lymph vessels, which include fluids, debris, and cells that have leaked out of the capillary beds.
Vessels and Pumps - Heart: What did the muscles in the wall of blood vessels become in the evolution of the cardiovascular system?
Dedicated pumps that formed a heart.
Vessels and Pumps - Heart: What was the first step in the evolution of the cardiovascular system?
The muscles in the wall of blood vessels got stronger, enabling them to generate force and pressure within the loop.
Vessels and Pumps - Heart: What is the relationship between the vasculature and the pump in the evolution of the cardiovascular system?
Evolution has led to many relationships between the vasculature and the pump
Closed Vs. Open Circulatory Systems: What is the difference between the cardiovascular system and the circulatory system in insects?
Insects have a cardiovascular system where blood vessels don’t go to capillaries but empty into a cavity called a sinus, making it an inefficient open circulatory system. Their circulatory fluid, called hemolymph, moves nutrients and hormones around the body, and they have a separate tracheal system for respiration.
Closed Vs. Open Circulatory Systems: How does an earthworm’s circulatory system work?
An earthworm’s circulatory system is a closed system, with blood contained within vessels all the time. It has multiple hearts and muscular blood vessels in the anterior segments that generate force and pressure to move fluids around. The animal breathes essentially over its entire body surface, collecting oxygen without the need for capillaries to exchange gases.
Closed Vs. Open Circulatory Systems: What key factor to remember when exploring the circulatory system of vertebrates?
The hearts become more complicated in structure with more chambers and more control over which circuits serve which parts of the body.
Origins of Multichambered Hearts and Circuits - How is the circulation in reptiles different from that in mammals?
Reptiles have a more complicated circulation, with more heart compartments, and better separation of the pulmonary and systemic circuits. In mammals, there is complete separation of the blood serving the lungs and the blood going to the rest of the body.
Origins of Multichambered Hearts and Circuits - Why are the left and right sides of the heart regulated differently?
The left and right sides of the heart are regulated differently because they have different functions and pressures to perform. The left ventricle has to pump blood to the rest of the body, which requires a lot of pressure, while the right ventricle only has to pump blood to the lungs, which have thin, fragile vessels.
Origins of Multichambered Hearts and Circuits - What is the role of the left ventricle in the heart?
The left ventricle is responsible for pumping blood to the systemic circulation that serves most of the body. It has to pump blood up to the brain and down to the feet, and have enough pressure to drive it all the way back to the heart. The left ventricle is a super strong pump with thick muscular walls in mammals.
Origins of Multichambered Hearts and Circuits - Why is the right ventricle thinner than the left ventricle?
The right ventricle is thinner than the left ventricle because it only has to generate enough force to pump blood through the pulmonary circuit to the lungs, which have thin, fragile vessels. It doesn’t need to produce as much pressure as the left ventricle.
Origins of Multichambered Hearts and Circuits - What happens to the right ventricle in chronic obstructive pulmonary disease (COPD)?
In chronic obstructive pulmonary disease, the need for oxygen causes the right ventricle to become a bit stronger by thickening the right wall of the heart. However, if the wall becomes too thick, it can impair the filling of the heart and the development of proper pressure and force, making it a poor pump.
Pacemaker Cells and Transmission of Signals: How can you make a pacemaker go faster?
By making the sodium channel a little bit leakier or having it stay open for longer, which depolarizes the cell to the threshold faster and starts the contraction faster.
Pacemaker Cells and Transmission of Signals: Why is it a problem if the wave of contractions continued from the SA node to the apex of the heart?
If the wave continued from the SA node to the apex of the heart, it would push blood to the bottom of the heart instead of pumping it out through the arteries, causing a problem.
Pacemaker Cells and Transmission of Signals: How are the pacemaker cells connected to the rest of the heart cells?
The pacemaker cells are connected to electrical fibers that send the contraction signal to the apex of the heart, triggering a contraction from the tip to the arteries that carry blood away from the heart.
Pacemaker Cells and Transmission of Signals: What type of sodium channel do pacemaker cells have?
Pacemaker cells have a type of sodium channel that shows a slow leak. As Na comes into the cell, it slowly depolarizes.
Pacemaker Cells and Transmission of Signals: What happens when the membrane potential of a pacemaker cell hits a threshold?
The depolarization causes the pacemaker to fire action potential.
Interaction Between Pressure and Flow: How is the capacity of a blood vessel estimated?
The capacity of a blood vessel is estimated by measuring its cross-sectional area.
Interaction Between Pressure and Flow: What happens to the cross-sectional area of blood vessels as you move from large arteries to small ones?
As you move from large arteries to small ones, the cross-sectional area is pretty constant, transitioning from a few large vessels to many small ones.
Interaction Between Pressure and Flow: What happens to blood velocity as the total cross-sectional area grows?
As the total cross-sectional area grows, blood velocity slows down.
Interaction Between Pressure and Flow: What happens to blood pressure as you move through the circuit?
Near the heart, the arteries experience each pulse of pressure from contraction. By the time the blood gets to the capillary bed, there is almost no evidence of a pulse in pressure, and flow is fairly regular.
Interaction Between Pressure and Flow: How is blood pressure measured?
Interaction Between Pressure and Flow: Blood pressure is measured in an artery that experiences the pulses of pressure from contraction. The highest pressure is the systolic pressure and the lowest pressure is the diastolic pressure. The mean arterial pressure is a weighted average of these two extremes, with diastolic pressure weighted twice as much as systolic pressure.
Interaction Between Pressure and Flow: Why is the slow blood flow in capillaries beneficial?
The slow blood flow in capillaries means more time for the capillaries to complete the exchange of materials with the surrounding tissues.
Determinants of Hemodynamics: What is cardiac output and how is calculated?
Cardiac output is a measure of the heart’s function expressed as the amount of blood pumped by the heart in one minute. It is calculated by multiplying stroke volume, the amount of blood pumped in one heartbeat, by heart rate, and the number of heartbeats per minute.
Determinants of Hemodynamics: How is the cardiovascular system regulated to maintain mean arterial pressure?
The cardiovascular system is regulated by changing the contractile properties of the heart and the nature of the resistance to flow. The body can alter the stroke volume, heart rate, or both, to change cardiac output. Resistance is also determined by the number of vessels in the circuit, the arterial smooth muscle contractions, the number of open capillary beds, and the properties of blood.
Determinants of Hemodynamics: How does resistance affect blood flow in the cardiovascular system?
Resistance affects blood flow by determining how difficult it is for blood to move around. Resistance is determined by the number of vessels in the circuit, the arterial smooth muscle contractions, the number of open capillary beds, and the properties of blood, such as how many blood cells are in circulation.
Circulatory Fluids: What is the main component of blood?
The main component of blood is plasma, which is a fluid that carries many proteins, metabolites, and hormones in the blood.
Circulatory Fluids: What is the function of erythrocytes?
Erythrocytes, also known as red blood cells, are responsible for carrying oxygen from the lungs to the body’s tissues and bringing carbon dioxide from the tissues back to the lungs to be exhaled.
Circulatory Fluids: How do animals control the levels of erythrocytes in the blood?
Animals control the levels of erythrocytes in the blood through the process of erythropoiesis. When oxygen levels are low, or blood has been lost, stem cells in the bone marrow are triggered to induce erythropoiesis to make new red blood cells.
Circulatory Fluids: What is the function of plasma in the blood?
Plasma in the blood carries many proteins, including antibodies, and most of the metabolites and hormones in the blood.
Evolved Respiratory System: What is the main reason why animals evolved cardiorespiratory systems?
Animals evolved cardiorespiratory systems to ensure that the enzyme cytochrome oxidase has its substrate, molecular oxygen, delivered and to remove CO2 and distribute metabolic water throughout the body.
23 Respiratory Gases - Partial Pressures: What is the difference between the pressure and concentration of a gas?
Pressure is the force per unit area exerted by a gas on its container, and it can be measured in units such as mm Hg, atmospheres, or torr. The partial pressure of a gas is the amount of total pressure that is due to that gas. Concentration, on the other hand, is the number of moles of the molecule per volume, and it is measured in molarity. For gases, it refers to the number of moles per liter volume.
23 Respiratory Gases - Partial Pressures: How does the concentration of oxygen in water compare to its concentration in the air?
Oxygen concentration in air is about 8.7 mM, whereas, at equilibrium, it will only be 0.3 mM in water. This is because oxygen does not dissolve in water easily. In contrast, CO2 dissolves in water as easily as it dissolves in air, and the concentrations of CO2 will be the same in air and water.
Respiratory Drive - Air Breathers: What happens if your blood starts to accumulate CO2?
If your blood starts to accumulate CO2, it will have an acidification effect on your blood, which will cause the chemosensors in your aorta and carotid arteries to signal your brain to increase respiration.
