Respiratory System
Inspiration is....
Inspiration — Breathing in; drawing air into the lungs
____________decreases the surface tension in the lungs, making inspiration less challenging.
Pulmonary surfactant decreases the surface tension in the lungs, making inspiration less challenging. Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by the cells of the alveoli (the tiny air sacs in the lungs). The main function of surfactant is to lower the surface tension at the air/liquid interface within the alveoli of the lung. Surfactant reduces the surface tension of fluid in the lungs and helps make the small air sacs in the lungs (alveoli) more stable. This keeps them from collapsing when an individual exhales. In preparation for breathing air, fetuses begin making surfactant while still in the womb.
Respiration occurs....
Respiration occurs when gases are exchanged between the outside environment and the inside of an organism. This is what humans do when they inhale oxygen and exhale carbon dioxide.
Respiratory Acidosis — Due to ________ and Body Responds by ____________.
Respiratory Acidosis — Due to Hypoventilation and Body Responds by Hyperventilation. Respiratory acidosis occurs due to inadequate breathing (hypoventilation). Hypoventilation is when breathing occurs at a abnormally slow rate, resulting in an increase amount of CO₂ in the blood. Respiratory acidosis causes CO₂ to accumulate, which leads to a drop in pH through carbonic anhydrase activity. The response to respiratory acidosis is hyperventilation. When CO₂ levels increase, the respiratory center in the brain tells you to breathe more rapidly. Hyperventilation is an increased depth and rate of breathing that becomes greater than demanded by the body needs; it causes dizziness and tingling of the fingers and toes and chest pain if continued. So the pH < 7.35 and here we will have an accumulation of protons (H⁺) 1. Respiratory Acidosis Example 1: People with Emphysema will hypoventilate and the CO₂ loss is hindered — aka CO₂ is accumulating. If CO₂ is not removed from the lungs fast enough, it "backs up" and protons (H⁺) will not be removed by bicarbonate anions (HCO₃⁻) as presented by carbonic anhydrase. 2. Respiratory Acidosis Example 2: Airway obstruction, or if a drug is given that depresses the respiratory center, we could likely see respiratory acidosis. A barbiturate ( a type of sedative or sleep-inducing drug) is such a drug! Asthma or Pneumonia too!
Respiratory Alkalosis — Due to ____________and Body Responds by _________________.
Respiratory Alkalosis — Due to Hyperventilation and Body Responds by Hypoventilation. Respiratory Alkalosis occurs due to rapid breathing (hyperventilation). This depletes carbon dioxide in the blood, which ultimately increases the pH — protons are NOT accumulated — through carbonic anhydrase activity. The response to respiratory alkalosis is hypoventilation. So the pH > 7.45 and here we have a loss of CO₂ and protons (H⁺) are not accumulating. This happens in cases of severe anxiety, early stages of aspirin overdose, or O₂ deficiency in high altitude. (The rising CO₂ and H⁺ ions are sensed by chemoreceptors in the carotid artery and the brain receives the message.)
Respiratory acidosis and alkalosis are the result of ___________
Respiratory acidosis and alkalosis are the result of breathing issues
Bohr Effect....
The Bohr effect states hemoglobin has decreased affinity for oxygen when carbon dioxide is high. This is because high amounts of carbon dioxide result in increased proton (H⁺) concentrations, which act to reduce hemoglobin and displace oxygen. Recall: when protons (H⁺) bind to hemoglobin, they reduce it. Reduced hemoglobin (H⁺Hb) undergoes a shape change that decreases the affinity for oxygen. Remember that as the erythrocytes become more acidic, the oxyhemoglobin (HbO₂) they contain is converted to reduced hemoglobin (H⁺Hb). This leads to the hemoglobin conformational change that decreases the affinity for oxygen so it may be released to the tissues. Remember that erythrocytes contain hemoglobin proteins that are used to transport 98% of oxygen. The oxygen that travels in this way, attached to hemoglobin, is known as oxyhemoglobin (HbO₂) Consider muscle that is rapidly contracting. Active muscle cells take up oxygen and release carbon dioxide as a result of increased cellular respiration. CO₂ and H⁺ promotes the release of O₂. In addition, red blood cells contain hemoglobin, which releases oxygen when carbon dioxide is high (Bohr effect) Another way to say that hemoglobin has decreased its affinity for O₂ is that hemoglobin literally dumps its O₂ off. This is called the Bohr Effect. The bottom line is that hemoglobin's oxygen binding decreases as the amount of CO₂ and H⁺ increase and this is called the Bohn Effect...on the oxygen dissociation curve this is represented as a right shift.
The Haldane Effect....
The Haldane Effect — (the removal of O₂ from Hemoglobin (deoxygenation of blood) increase affinity for CO₂ The Haldane effect states that the deoxygenation of blood increases its ability to carry carbon dioxide. This can be thought of as a natural result of the Bohr effect: reduced hemoglobin (H⁺Hb) has a reduced affinity for oxygen. It also has a greater affinity for carbon dioxide and a greater capacity to form carbaminohemoglobin (HbCO₂). So bottom line is that the deoxyform of hemoglobin increases its ability to carry CO₂. In other words, the removal of O₂ from hemoglobin will increase its affinity for CO₂. HbCO₂ is the major contributor to this effect. HbCO₂ is carbaminohemoglobin, a strange name indeed. The CO₂ binds to the amino groups of lysine and arginine residues in hemoglobin.
The capability of binding oxygen molecule, with heme proteins, is what makes a difference in myoglobin and hemoglobin.....
The capability of binding oxygen molecule, with heme proteins, is what makes a difference in myoglobin and hemoglobin. Hemoglobin is called tetrameric hemoprotein, while myoglobin is called monomeric protein. Myoglobin can bind to only one molecule of oxygen since it contains only one heme group. Hemoglobin is found systematically all over the body, while myoglobin is found in muscle tissues only. Hemoglobin is made of protein and a prosthetic group and is well known for carrying oxygen pigment. It is the most vital part to sustain life as it works in transporting oxygen as well as carbon dioxide throughout the body. Myoglobin works for muscle cells only, by receiving oxygen from red blood cells and further carrying it to a mitochondrial organelle of muscle cells. Subsequently, this oxygen is used for cellular respiration to create energy. They both contain iron at the center of the heme group. But myoglobin has a much higher oxygen affinity at low partial pressures of oxygen. ... Myoglobin has one heme group and therefore can only bind one molecule of oxygen.
The cooperative binding of oxygen in hemoglobin renders hemoglobin to me more efficient oxygen transporter. Why?
The cooperative binding of oxygen in hemoglobin renders hemoglobin to me more efficient oxygen transporter. Why? when four oxygen molecules are bound, and of the subunits release, the other subunits unload oxygen more readily.
The ___________is a large skeletal muscle located at the bottom of the lungs. It is innervated by the ____________. When it contracts, it pulls the lungs downward.
The diaphragm is a large skeletal muscle located at the bottom of the lungs. It is innervated by the phrenic nerve coming from the medulla oblongata. When it contracts, it pulls the lungs downward.
The epiglottis is ....
The epiglottis is a leaf-shaped flap of cartilage located behind the tongue, at the top of the larynx, or voice box. The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled.
The esophagus .....
The esophagus is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa. The esophagus runs behind the windpipe (trachea) and heart, and in front of the spine. ... They keep food and secretions from going down the trachea (windpipe).
The larynx ...
The larynx is the structure the epiglottis will divert air to. It is also known as the voice box, because it contains the vocal cords. The cough reflex is activated if anything besides air enters the larynx. If you've ever choked on food, it's probably because your epiglottis didn't do its job of diverting food into the esophagus.
The level of___________ in our body is what controls your breathing.....
The level of carbon dioxide (CO2) in our body is what controls your breathing. When carbon dioxide reaches a certain level, a signal is sent from the breathing center in your brain stem to the breathing muscles, which triggers an inhalation. Upon exhalation, we exhale carbon dioxide and a new breathing cycle starts. Carbon dioxide is produced in your body all the time, and when you breathe, you exhale the CO2 that has been built up in our body. The more active we are, the more CO2 is produced. That's why we breathe more when we are out jogging compared to when we sit in the sofa chilling out.
The ____________ of the brain controls respiration by telling the respiratory muscles, primarily the ___________ when to contract, via signals through the_____________
The medulla oblongata of the brain controls respiration by telling the respiratory muscles, primarily the diaphragm when to contract, via signals through the phrenic nerve. The medulla is influenced by the central and peripheral chemoreceptors.
The nasal cavity....
The nasal cavity is the first structure air contacts when we inspire air. The nose warms and moistens incoming air so it does not dry out the rest of our airways. Goblet cells and ciliated epithelial cells are found here.
The pharynx divides into....
The pharynx divides into the larynx and esophagus, meaning it acts as a passageway for food and air. The epiglottis is a structure in the throat that diverts food and air into their appropriate tubes.
The pharynx ....
The pharynx is a common passage from the nasal cavity, which marks the beginning of the throat. Here, dust and mucus are swept back by ciliated epithelial cells, which allows the debris to be disposed off by spitting or swallowing.
The phrenic nerve....and is controlled by the ______
The phrenic nerve is a nerve that originates from the neck and descends through the thorax to innervate the diaphragm. It is the only source of motor innervation to the diaphragm and therefore plays a crucial role in breathing. The phrenic nerve is controlled by a lobe in the brain called the medulla oblongata. The medulla oblongata controls respiration by informing respiratory muscles, mainly the diaphragm on when to contract, via signals through the pheneric nerve.
The pleura is a dual layered membrane that covers each lung.....
The pleura is a dual layered membrane that covers each lung. a. The outer layer is called the parietal layer, which contacts the thoracic cavity. b. the inner layer of the pleura is known as the visceral layer and it makes contact with the lungs themselves. c. There is a space between the parietal and visceral layers, called the pleural space. The pleural space contains fluid always at a lower pressure than the atmospheric pressure. This is called intrapleural or thoracic negative pressure. This negative pressure is vital for controlling airflow through the lungs and preventing the lungs from collapsing in on themselves.
The main intracellular buffer system is...
The principle intracellular buffer is the phosphate buffer Phosphate functions as the main intracellular buffer system in humans Phosphate buffer system operates in the internal fluids of all cells. It consists of dihydrogen phosphate ions as the hydrogen ion donor ( acid ) and hydrogen phosphate ion as the ion acceptor ( base ) . If additional hydroxide ions enter the cellular fluid, they are neutralised by the dihydrogen phosphate ion. If extra hydrogen ions enter the cellular fluid then they are neutralised by the hydrogen phosphate ion.
Lungs differ in size because...
The right and left lungs differ in size due to the position of the heart. The heart lies to the left of the sternum; therefore, the left lung is smaller than the right lung to make room for the heart. The left lung has just two lobes, whereas the right lung has three lobes.
The trachea (or windpipe)....
The trachea (or windpipe) is a wide, hollow tube that connects the larynx (or voice box) to the bronchi of the lungs. It is an integral part of the body's airway and has the vital function of providing air flow to and from the lungs for respiration.
The lower respiratory tract is made up of....
The trachea, bronchi, bronchioles, and alveoli make up the lower respiratory tract.
The upper respiratory tract is made up of....
The upper respiratory tract is made up of the nasal cavity, pharynx, and larynx.
Two Forms of Hemoglobin....
There are two states in the hemoglobin, the T state (the tense state) and the R state (the relaxed state). The T state has less of an affinity for oxygen than the R state. a) T Form....low O₂ affinity form "deoxyhemoglobin" b) R Form....high O₂ affinity form "oxyhemoglobin" HEMOGLOBIN Comprises four polypeptides instead of just one as seen in myoglobin T-form for "taut" or "tense," in which the polypeptide chains are restricted in their movement.- This is hemoglobin's deoxy form; its oxygen affinity is low. This is the R-form for "relaxed."- The weaker ionic and hydrogen bonds allow the subunits to move slightly in this state.- This is hemoglobin's oxy form; its oxygen affinity is high. Reversible arrows to represent the conformational change between the T-form and R-form hemoglobin molecules.
There are two types of epithelial cells in human alveoli....
There are two types of epithelial cells in human alveoli Type 1 epithelial cells are involved in structural support of the alveoli. Type 2 epithelial cells produce surfactant. Surfactant reduces surface tension within the alveolus, therefore preventing fluid from collapsing it.
This is how the bicarbonate Buffer System works.....
This is how the bicarbonate Buffer System works.....
Tidal volume.....
Tidal volume is the volume of air that moves through the lungs between a normal inhalation and exhalation.
Total lung capacity....
Total lung capacity is the sum of the vital capacity and the residual volume it is that maximum volume the lungs could possibly hold at any given time.
Vital capacity...
Vital capacity is the maximum amount of air that can be exhaled after a maximum inhalation. includes: inspiratory reserve volume expiratory reserve volume tidal volume
What happens to lungs when he exhale?
What happens to lungs when he exhale? - Exhalation/Expiration = Internal Intercostal muscle ↑ Interpleural Pressure Increases ;↓ Lung, Rib, and Internal Intercostal Muscle Decreases During expiration, the diaphragm and external respiratory muscles relax, and a "recoil" occurs. The elastic tissue of the lungs, abdominal organs, etc. suddenly spring back; this causes air pressure within the lungs to increase. Air will then be squeezed out of the lungs into the air passages. Internal Intercostal Muscles: The internal intercostal muscles sit between rib cages, these contract to bring ribs closer together When a person exhales, the medulla oblongata sends a signal through the pheneric nerve telling the internal intercostal muscles to contract. When internal intercostal muscles contract, these muscles bring ribs closer together so that the volume of the lungs and thoracic cavity decrease so air can be pushed out. The diaphragm and external intercostal muscles relax and undergo elastic recoil. This elastic recoil causes the volume of the lungs and thoracic cavity to decrease. This process makes the pressure in the interpleural space to increase which allows air to flow out of the lungs because air moves from high to low concentration.
What happens to lungs when we inhale?
What happens to lungs when we inhale? - Inhalation/Inspiration = External Intercostal muscles ↓ Interpleural Pressure Decreases ; ↑ Lung, Rib, and External Intercostal Muscles Increases During inhalation in mammals, the thoracic cavity is expanded and the diaphragm contracts an therefore moves down. This is negative pressure breathing. External intercostal muscles are the small muscles between the ribs. When these contract due to intercostal nerve innervation, the rib cage fans up and out hence increasing the volume of the lungs. When a person inhales, the medulla oblongata sends a singal through the pheneric nerve telling the external intercostal muscles to contract. When they contract these muscles causes the rib cage to fan out which makes the volume of the lungs and thoracic cavity increase to allow room for air to enter in. This action also causes the pressure in the intrapleural space to decrease (become more negative) which causes air to flow into the lungs, this is because air flows from high to low concentration. The higher atmospheric pressure forces air into the respiratory tract and the air passages and the lungs inflate.
when a muslce is injured, heart or skeletal, _____ is released into the blood.....
When a muslce is injured, heart or skeletal, myoglobin is released into the blood. Within 2-3 hours, Myoglobin levels in the blood rise after heart or skeletal muscle injury. At about 10 hours after injury, myoglobin levels peak Myoglobin can also appear in the urine after muscle injury.
The principle blood buffer is ______........
When carbon dioxide is dissolved in the blood, it creates a buffer composed of: Bicarbonate ions, HCO3- Carbonic Acid, H2CO3 Carbon Dioxide, CO2 All three exist is equilibrium to each other. The principle Blood Buffer is bicarbonate, HCO3- The bicarbonate ion (HCO3-) is part of the buffer system to be able to neutralize hydrogen ions hence increasing the pH of the blood (making it more basic since we are removing protons).
metabolic acidosis and metabolic alkalosis are the result of......
metabolic acidosis and metabolic alkalosis are the result of any other imbalance that changes oxygen, carbon dioxide, or proton (H⁺) concentrations.
oxygen dissociation curve Factors....Anemia...
1. Anemia Anemia is a condition that occurs in individuals who have low levels of heme iron (Fe²⁺). Ultimately, it reduces their capacity to carry oxygen meaning their hemoglobin has a lower affinity to carry oxygen; there aren't enough healthy red blood cells to carry adequate oxygen throughout the body. Remember that each of the four peptides in a hemoglobin protein are equipped with a single heme cofactor. Heme cofactors are organic molecules that contain iron atoms. These iron atoms allow a single oxygen molecule to bind to them when they exist as ferrous iron (Fe²⁺). Heme irons oxidized to ferric iron (Fe³⁺) can't bind to oxygen Sickle Cell Anemia is a inhertited form of anemia. In Sickle Cell anemia, red blood cells become rigid and sticky and are shaped like cresent moons. If you have sickle cell anemia, then there is a problem with your hemoglobin. Hemoglobin is a protein in red blood cells that carry oxygen throughout the body..the cells are supposed to be disc shaped, but this changes them into a cresent shape.
2. High Altitudes (Increase of 2,3 Diphosoglycerate due to anaerobic respiration)
2. High Altitudes (Increase of 2,3 Diphosoglycerate due to anaerobic respiration) The air is "thinner" at high altitudes meaning that there are fewer oxygen molecules per volume of air. So to compensate for the decrease in oxygen, the body's hemoglobin has to release oxygen to the tissues in need. So at high altitudes, the amount of 2,3-Diphosphoglycerate increases substantially. Thus, the oxygen dissociation curve shifts to the right because O₂ will be dumped off and released to the tissues. This compensates for the lowered oxygen concentration. Have you ever tried running at a very high altitude? Not so easy! When there is insufficient oxygen to power aerobic respiration, 2,3-diphosphoglycerate accumulates as the result of anaerobic respiration occurring. This metabolite decreases the affinity for oxygen (right shifts the curve) by binding to hemoglobin and changing its shape. This is a clever way to get oxygen to the cells that want to do aerobic respiration when the oxygen supply is too low.
4. Increased body temperature
4. Increased body temperature results in a right shifted curve. This is because higher body temperatures correspond to higher metabolic rates, which increases the cellular requirement for oxygen (i.e., cellular respiration increases so hemoglobin affinity for oxygen decreases).
5. High partial pressures of carbon dioxide
5. High partial pressures of carbon dioxide result in a right shifted curve. This is true because carbon dioxide increases the concentration of protons (H⁺) via carbonic anhydrase. The increased proton (H⁺) concentration decreases the pH.
6. Decreased pH
6. Decreased pH further right shifts the curve. This is because protons (H⁺) compete with oxygen in oxyhemoglobin (HbO₂). When protons (H⁺) bind, they form reduced hemoglobin (H⁺Hb). Reduced hemoglobin (H⁺Hb) undergoes conformational changes that lower oxygen affinity. Interestingly, these changes increase the affinity for carbon dioxide, resulting in a greater capacity to form carbaminohemoglobin (HbCO₂).
A Buffer.....
A buffer helps maintain pH. Buffers can release or gain H+. If a small amount of OH- ions are introduced into a buffer solution, the conjugate acid will react with it. If a small amount of hydronium ions is added, the conjugate base reacts with it. These buffers act as "sponges" pH can be calculated using the Henderson-Hasselbach Equation. pH= pKa + Log [base]/[Acid]
About 98% of oxygen is transported by....
About 98% of oxygen is transported by binding to hemoglobin proteins found within erythrocytes. The oxygen that travels in this way is referred to as oxyhemoglobin (HbO₂). The remaining small percentage of oxygen travels as oxygen gas dissolved in the plasma. Remember that plasma is the colorless watery fluid of the blood and lymph that contains no cells, but in which the blood cells (erythrocytes, leukocytes, and thrombocytes) are suspended.
Active muscle cells - Bohr Effect and Halane Effect
Active muscle cells take up oxygen and release carbon dioxide as a result of increased cellular respiration. In addition, red blood cells contain hemoglobin, which releases oxygen when carbon dioxide is high (Bohr effect) and has increased ability to bind carbon dioxide in deoxygenated blood (Haldane effect). Therefore, O2 diffuses into the surrounding muscle cells from the blood, while CO2 diffuses into the blood from the muscle cells. The blood leaving the capillary bed will contain high CO2 and low O2
After air passes through the trachea....
After air passes through the trachea, it flows into two bronchi. These bronchi enter the lungs and further branch into narrower bronchioles. The bronchioles end in small sacs known as alveoli.
After the larynx, air flows....
After the larynx, air flows into the trachea. The trachea is reinforced by C-shaped cartilage so it does not collapse. Additionally, it is covered in ciliated epithelial cells that further filter the air.
residual volume....
After you exhale, some air still remains in the lungs, the minimal amount of air always present in the lungs (to prevent them from collapsing) is known as the residual volume.
Alveoli ....
Alveoli — the tiny air sacs of the lungs which allow for rapid gas exchange. The gas exchange occurs across the interface (point where two things meet) between the alveolar membrane and the alveolar capillaries surrounding it.
An oxygen dissociation curve shows....
An oxygen dissociation curve shows the percentage of hemoglobin polypeptides that are fully saturated with oxygen under various conditions. The oxygen dissociation curve shows the relationship between the partial pressure of oxygen in the blood and the saturation of the hemoglobin molecule. In general, there are two things you should know about hemoglobin dissociation curves: 1. A right-shifted curve is representative of hemoglobin binding more loosely to oxygen, meaning it is easier to release oxygen to the tissues. 2. A left-shifted curve is representative of hemoglobin binding more tightly to oxygen, which means it is harder to release oxygen to the tissues.
At the beginning of inspiration, the intrapleural pressure begins to decline. Intrapleural pressure is most negative when we are at ____________ At the beginning of exhalation, the intrapleural pressure begins to rise. The intrapleural pressure of the lungs is the least negative at _____________.
At the beginning of inspiration, the intrapleural pressure begins to decline. As more air keepings coming into the lungs because of the negative pressure, the intrapleural space continously declines until it can no longer hold any more air in the lungs. Hence, Intrapleural pressure is most negative when we are at peak inspiration. which is the maximum amount of air our lungs can totally inhale in. At the beginning of exhalation, the intrapleural pressure begins to rise. As more air keeps leaving the lungs because the increase of pressure in the lungs compared to the outside of the lungs compels the air in the lungs to exit (from high pressure to low pressure). Hence, The intrapleural pressure of the lungs is the least negative (most positive) at peak expiration which is the maxmum amount of air our lungs can release.
The Bohr and Haldane effects neatly describe how gas exchange occurs throughout the entire body. Let's see how:
At the level of the tissues, there is a relatively high partial pressure of carbon dioxide and relatively low partial pressure of oxygen. Therefore, carbon dioxide travels down its pressure gradient and into the erythrocyte via simple diffusion.
Bicarbonate Buffering System.........
Bicarbonate Buffering System - to help remove CO2 to the lungs to be exhaled and hemoglobin acts as a buffer by capturing protons (H⁺Hb) and preventing the blood from getting too acidic.
The main extracellular buffer system in humans consists of...
Bicarbonate is the main extracellular buffer system in humans that is used to regulate pH through the carbonic anhydrase reaction. The main extracellular buffer is bicarbonate. This is how CO2 is transported throughout the body. The body uses pH sensors to determine how much we have to breathe. If we are exercising vigorously then our cells will produce large amounts of CO2, which will lower our extracellular pH (make it more acidic due to the CO2), which will make us breathe more to expel the excess CO2. The main extracellular buffer system in humans is bicarbonate The bicarbonate buffering system maintains the extracellular (plasma) pH levels. It follows the general formula of: CO2 + H2O ⇌ H2CO3 ⇌ HCO3- + H+ As you can predict via Le Chatelier's principle, when CO2 levels are high, CO2 combines with water to form H2CO3, which dissociates into HCO3- (which explains why our pH lowers with CO2 levels are high) and H+. This HCO3-(bicarbonate) acts as the primary extracellular buffer. The body uses pH to affect changes in respiratory rate based on changes in blood pH levels.
Acidosis and Alkalosis.....
Blood pH is approximately 7.4 Normally we see a range of 7.35-7.45 Below 7.35 = Acidosis Above 7.45 = Alkalosis In acidosis, we see a depression of the Central Nervous System synaptic transmission. Disorientation and coma can result. Death soon follows. In Alkalosis, we see hyperexcitability in the Central Nervous System and the Peripheral Nervous System with extreme nervousness and spasm of muscle. Death can result if untreated. The pH balance can be easily upset. CO2, lactic acid, ketone bodies, etc. can all contribute to lowering the blood pH. Three main mechanisms can help maintain pH: 1) Buffers 2) CO2 removal by the lungs 3) H+ removal by the kidneys
To Summarize Breathing Pace....
Breathing is under the control of two main areas of the brain: Medulla Oblongata, and the Pons. The pH of the surrounding tissues gives important information regarding CO₂ levels. As metabolic activity goes up (you are working out), the CO₂ in the blood increases as lactic acid is produced, hence the pH is lowered (aka more H⁺ protons). The Medulla will respond by increasing the breathing rate. Notice how, it is the CO₂ that has the effect on breathing control centers, NOT the O₂ concentration in the blood. If, however, O₂ levels did drop low...in times of hypoxia (deficiency in the amount of oxygen reaching the tissues), or if you climbed Mount Everest, O₂ "sensors" located in the aorta and carotid arteries (carotid arteries branch off the aorta) can signal the brain to increase the breathing rate. These "sensors" are chemoreceptors. The carotid body can detect changes in blood gas composition. This small cluster of chemoreceptors is very sensitive to pH and even temperature changes.
Bronchi...
Bronchi — the major air passageway of the lungs which diverge from the windpipe
Bronchioles...
Bronchioles — minute branches the bronchi divide into
Which factors will result in a Right shifted curve - meaning hemoglobin has a lower affinity for oxygen.
CADET, face Right + Anemia CADET = Carbon dioxide, Acid, 2,3 Diphosphoglycerate, Exercise Temperature. + Anemia An increase in any of the 'CADET' factors will result in a Right shifted curve - meaning hemoglobin has a lower affinity for oxygen.
Which factors will result in a left-shifted curve - meaning hemoglobin has a higher affinity for oxygen.
CADET, face Right! + Fetal Hemoglobin CADET = Carbon dioxide, Acid, 2,3-Diphosphoglycerate, Exercise Temperature. + Fetal Hemoglobin A decrease in any of the 'CADET' factors will result in a left shifted curve - meaning hemoglobin has a higher affinity for oxygen.
How does the central chemoreceptors work.....
CO2 + H2O <-> H2CO3 <-> HCO3- + H+ Carbonic anhydrase can be found in the fluid of the brain (cerebrospinal fluid). This means the carbon dioxide is converted to carbonic acid (H₂CO₃), which dissociates into a bicarbonate anion (HCO₃⁻) and a proton (H⁺). As protons (H⁺) accumulate (because they can't cross the blood brain barrier), the pH in cerebrospinal fluid decreases - i.e it becomes more acidic. The central chemoreceptors detect changes in the acidity of the cerebrospinal fluid. When it is more acidic, the central chemoreceptors influence the medulla oblongata to increase the breathing rate.
___________ is more soluble in blood than oxygen is....
Carbon dioxide is more soluble in blood than oxygen is. It can travel in the blood plasma as dissolved carbon dioxide gas, or by binding to hemoglobin. Most carbon dioxide travels dissolved in the blood plasma as bicarbonate anion (HCO₃⁻). Carbon dioxide that travels bound to hemoglobin is called carbaminohemoglobin (HbCO₂)
Carbon dioxide molecules are transported in the blood from body tissues to the lungs by one of three methods.....
Carbon dioxide molecules are transported in the blood from body tissues to the lungs by one of three methods: 1. Dissolution directly into the blood Carbon dioxide is more soluble in blood than oxygen. About 10% of all carbon dioxide is dissolved in the plasma. 2. About 20% of CO2 is transported by hemoglobin (carbamino hemoglobin -HbCO₂) Note that carbon dioxide CAN bind to hemoglobin and be transported, its just NOT THAT EASY so the body tries to find alternatives. Carbon dioxide can bind to plasma proteins or can enter red blood cells and bind to hemoglobin. This form transports about 20% of the carbon dioxide. When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed. Binding of carbon dioxide to hemoglobin is reversible. Therefore, when it reaches the lungs, the carbon dioxide can freely dissociate from the hemoglobin and be expelled from the body. Carbon dioxide is more soluble in blood than oxygen is. It can travel in the blood plasma as dissolved carbon dioxide gas, or by binding to hemoglobin. Most carbon dioxide travels dissolved in the blood plasma as bicarbonate anion (HCO₃⁻). Carbon dioxide that travels bound to hemoglobin is called carbaminohemoglobin (HbCO₂) 3. The majority of carbon dioxide molecules (85 percent) are carried as part of the bicarbonate buffer system. About 85% of CO2 is carried as part ofthe bicarbonate buffer system. In this reaction, the purpose is to carry CO2 from your tissues and into your lungs so that we can get rid of it. The problem is that unlike oxygen, carbon dioxide cannot easily be carried by hemoglobin. So we need some other way to carry carbon dioxide into your bloodstream and then into your lungs for disposale. Note that carbon dioxide CAN bind to hemoglobin and be transported, its just NOT THAT EASY so the body tries to find alternatives. So what we do is that we convert CO2 into something that can be dissolved into your bloodstream and that is bicarbonate anion, HCO3-. Bicarbonate anion will be able to dissolve easily into your blood, allowing us to easily transport CO2 into the lungs, so that it can be ultimately exhaled and hence removed.
Carbon Monoxide is a deadly gas for humans...how does this work?
Carbon monoxide is a deadly gas that has a 200x greater affinity for hemoglobin than oxygen. If carbon monoxide is present, it will convert oxyhemoglobin (HbO₂) to carboxyhemoglobin (HbCO). by displacing off the oxygen molecule on the hemoglobin and then attaching itself onto the hemoglobin molecule, hence forming carboxyhemoglobin. This essentially suffocates our cells, and the only way to treat someone with carbon monoxide poisoning is to administer 100% pure oxygen. Hemoglobin is an iron-containing oxygen transport protein in the red blood cells of most mammals. Simply put, it's a carrier protein. Interestingly it doesn't carry carbon dioxide in the same way it does for oxygen. Oxygen binds to the iron atoms in the protein whereas carbon dioxide is bound to the protein chains of the structure. Carbon dioxide doesn't compete with oxygen in this binding process. However, carbon monoxide is a very aggressive molecule. It's a colorless, odorless, and tasteless gas that is lighter than air and can be fatal to life. It has a greater affinity for hemoglobin than oxygen does. It displaces oxygen and quickly binds, so very little oxygen is transported through the body cells.
Carbonate Buffer System ....
Carbonate Buffer System is used to keep pH levels in balance in the blood Many of the most recognizable parts of nature function by maintaining some sort of balance. The carbonate buffering system is one of the most important buffering systems in nature, which helps maintain that balance. The purpose of the carbonate buffer system is to control the pH levels in the blood. Remember a buffer helps to resist pH change. pH is a measurement of acidity. The lower the pH, the more acidic the solution. Carbon dioxide is an essential part of the carbonate buffer system. Humans breathe in oxygen and breathe out carbon dioxide. This process sounds simple, but the details are actually quite complex. During the process of breathing, humans convert sugar into energy. Carbon dioxide is a waste product of this process. Carbon dioxide is released into the blood, travels to the lungs and is exhaled. Because carbon dioxide is a weak acid, the more carbon dioxide in the blood, the more acidic the blood becomes. Carbon dioxide has the chemical formula CO₂. This means that for every one molecule of carbon, there are two molecules of oxygen. When dissolved in water, carbon dioxide forms carbonic acid, H₂CO₃. Carbonic acid can lose two hydrogen atoms, or protons. The loss of protons in a solution is what makes that solution acidic.
Cellular respiration refers...
Cellular respiration refers to the metabolic processes cells utilize to breakdown carbohydrates into ATP, the energy currency that allows organisms to function.
Central Chemoreceptors.......
Central Chemoreceptors So more CO2 being produced means more protons hence lower pH which triggers the medulla oblongata to start breathing more rapidly. Central chemoreceptors are contained in the medulla oblongata itself. As such, these are protected by the blood brain barrier. Carbon dioxide can diffuse across the blood brain barrier, but protons (H⁺) can't. Mnemonic: central chemoreceptors are in the central nervous system (brain).
Ciliated epithelial cells .....
Ciliated epithelial cells move debris that gets trapped in the mucus a goblet cell secretes. For this reason, ciliated epithelial cells and goblet cells are often found in proximity.
Cooperativity (aka cooperative bonding) occurs when...
Cooperativity (aka cooperative binding) occurs when the binding of one molecule makes the binding of another molecule more favorable. This is seen when gases bind to hemoglobin. For example, when a single oxygen molecule binds to a heme cofactor, the shape of the polypeptide changes. This makes it more favorable for another oxygen to bind to another heme cofactor. The first oxygen to bind to a heme group is the hardest to bind, the second is easier, and the third and fourth are respectively even easier. The same process works in reverse when an oxygen leaves a heme group, the shape of the polypeptide changes and makes it more likely for the next oxygen to unbind, then the next, and so on. Therefore, cooperativity is an important way the body regulates how much oxygen is taken up by the blood and how much is offloaded to the tissues.
Regulation of Blood Acidity.....
During cellular respiration, humans breathe in oxygen. The body uses this oxygen as part of the process of converting sugar and other molecules into energy. A waste product of this process is carbon dioxide. Carbon dioxide is released into the blood. As the levels of carbon dioxide increase, the equilibrium of the carbonate buffer shifts. More carbonic acid H2CO3 is made, which then increases the acidity of the blood. Because the release of carbon dioxide into the blood shifts the carbonate buffer equilibrium, the body needs to remove the excess carbon dioxide in order to regulate the pH level. Therefore, blood carries the carbon dioxide to the lungs where it is exhaled. The speed and depth of breathing regulates the amount of carbon dioxide that is exhaled. Faster, deeper breathing exhales more carbon dioxide. The regulation of the pH of the blood is a precise process. When the blood has too much or two little acid, the results are known as acidosis and alkalosis, respectively. Lung or breathing disorders can cause respiratory acidosis and respiratory alkalosis through a dysregulation of the amount of carbon dioxide exhaled during respiration. Too little carbon dioxide exhaled will decrease the acidity of the blood, whereas too much carbon dioxide exhaled will increase the acidity of the blood.
3. Vigorous Exercise
During exercise more respiration occurs, and hence more oxygen is required. So the oxygen dissociation curve is shifted to the right. Exercise increases body temperature and the cellular metabolic rate. As cells burn through more and more nutrients, they release more and more carbon dioxide, which increases the acidity via carbonic anhydrase. Therefore, hemoglobin has a lower affinity for oxygen and a right shift occurs!!!! Remember that higher the metabolic rate of an organism, the greater will be its O₂ demand. This means the curve will be shifted to the right!!
Erythrocytes are....
Erythrocytes are red blood cells that travel in the blood. Their characteristics of being red, round, and like rubber give them the ability to complete their specific functions which is to carry oxygen from the lungs to the body, and bring carbon dioxide back to the lungs to be expelled. Red blood cells (erythrocytes) house millions of tetrameric hemoglobin polypeptides. Each of the four peptides in a hemoglobin protein are equipped with a single heme cofactor. Heme cofactors are organic molecules that contain iron atoms. These iron atoms allow a single oxygen molecule to bind to them when they exist as ferrous iron (Fe²⁺). Heme iron oxidized to ferric iron (Fe³⁺) can't bind to oxygen. A single erythrocyte can contain 300 million hemoglobin molecules, and thus more than 1 billion oxygen molecules. Each iron ion in the heme can bind to one oxygen molecule; therefore, each hemoglobin molecule can transport four oxygen molecules.
Expiration is....
Expiration — Breathing out; releasing air from the lungs through the nose or mouth
7. Fetal hemoglobin
Fetal hemoglobin shows a left shifted curve relative to an adult's hemoglobin dissociation curve. This is because fetal hemoglobin binds oxygen more tightly than adult hemoglobin to ensure oxygen can be acquired from maternal blood. Let us consider fetal hemoglobin. The fetus gets O₂ from the mother's bloodstream by means of the placenta. Fetal hemoglobin has a higher O₂ affinity than does adult hemoglobin for two reasons: 1. Adult hemoglobin has 2 alpha chains, and 2 beta chain — Fetal hemoglobin has 2 alpha chains, and 2 gamma chains. 2. Fetal hemoglobin binds to 2,3-DPG less strongly than does adult hemoglobin. The net effect of the primarily structural differences between fetal hemoglobin and adult hemoglobin is that 2,3-DPG binds less tightly to deoxyHbF by comparison to deoxyHbA. Remember that 2,3-BPG decreases the affinity for oxygen by binding to hemoglobin and causing a conformational change that makes oxygen's binding to hemoglobin loose and hence releasing oxygen from hemoglobin, which in turn shifts the curve to the right. But HbF does not hold 2,3-BPG as tightly compared to adult HbA. HbA stabilizes the deoxy form which means the "preferred" conformation will be to have O₂ dumped off!! Thus, the hemoglobin curve for fetal hemoglobin is shifted to the left since it will keep its O₂ and use it for its own critical development.
functional residual capacity....
Functional residual capacity is the entire volume of air still present in the lungs after a normal exhalation. It is also the sum of the expiratory reserve volume and the residual volume.
Goblet cells are....
Goblet cells are columnar cells that secrete mucus to trap debris.
Hemoglobin is a allosteric protein because.....
Hemoglobin is exclusively found in red blood cells where its main job is to transport oxygen from the lungs to the tissue capillaries Since there are four hemes, this molecule can carry four oxygen molecules Unlike myoglobin which is a monomer of one chain, hemoglobin is a tetramer and shows what is called cooperativity. What does this mean? When an oxygen binds to hemoglobin, any salt bridges are broken which causes the conformation to change. The binding of additional oxygen molecules becomes more easily attained. In other words, the affinity for oxygen binding is now enhanced. As you can see hemoglobin is a allosteric protein. The binding of oxygen to one subunit affects the other subunits. Binding to myoglobin is NOT cooperative.
Enzymes show maximum activity at a characteristic pH, thus.....
In all aspects of metabolism and cellular activities, control of pH of the cells and body fluids if of great importance. Enzymes show maximum activity at a characteristic pH, thus on either side of the optimum pH their catalytic activity will decrease markedly. Remember...the pH is a log scale. Thus is the pH of the stomach was about 2 and the pH of the small intestine was about 8, how much more acidic is the stomach than the small intestine?
The Purpose of the Bicarbonate Buffering System.........
In this reaction, the purpose is to carry CO2 from your tissues and into your lungs so that we can get rid of it. In this bicarbonate buffering system, the hemoglobin acts as a buffer by capturing protons (H⁺Hb) and preventing the blood from getting too acidic! The problem is that unlike oxygen, carbon dioxide cannot easily be carried by hemoglobin. Important to note that carbon dioxide can bind with hemoglobin BUT NOT EASILY So we need some other efficient and easy way to carry carbon dioxide into your bloodstream and then into your lungs for disposale. So what we do is that we convert CO2 into something that can be dissolved into your bloodstream and that is bicarbonate anion, HCO3-. Bicarbonate anion will be able to dissolve easily into your blood, allowing us to easily transport CO2 into the lungs, so that it can be ultimately exhaled and hence removed. Purpose of Bicarbonate Buffer System is to convert CO2 (cannot be easily carried by hemoglobin) into bicarbonate anion, HCO3-, (can be easily dissolved into your bloodstream) so that CO2 from your tissues can be transported easily into the lungs so that it can be exhaled and removed. In this bicarbonate buffering system, the hemoglobin acts as a buffer by capturing protons (H⁺Hb) and preventing the blood from getting too acidic! The benefit of the bicarbonate buffer system is that carbon dioxide is "soaked up" into the blood with little change to the pH of the system. This is important because it takes only a small change in the overall pH of the body for severe injury or death to result. The presence of this bicarbonate buffer system also allows for people to travel and live at high altitudes: When the partial pressure of oxygen and carbon dioxide change at high altitudes, the bicarbonate buffer system adjusts to regulate carbon dioxide while maintaining the correct pH in the body.
It is possible that breathing changes can occur as a response to metabolic acidosis or alkalosis; however, respiratory changes are never the cause of metabolic acidosis or alkalosis.
It is possible that breathing changes can occur as a response to metabolic acidosis or alkalosis; however, respiratory changes are never the cause of metabolic acidosis or alkalosis.
Lungs are...
Lungs are essentially hollow pouches that certain animals use to breathe. This is made possible by manipulating the pressure felt by the outside of the lungs, which leads to changes in the volume of air found inside the lungs. The lungs are found in the thoracic cavity, and they are encased by the rib cage.
Metabolic Acidosis is....
Metabolic Acidosis is a condition that occurs when the body produces excessive quantities of acid.
Metabolic Alkalosis is....
Metabolic Alkalosis is a condition in which the pH of tissue is elevated beyond the normal range hence decreased proton (H⁺) concentration.
expiratory reserve volume....
More forceful exhalations allow more air to be expired than usual (above the tidal volume), this is known as expiratory reserve volume.
inspiratory reserve volume....
More forceful inhalations allow more air to be inspired than usual (above the tidal volume), and this is known as inspiratory reserve volume.
Muscle contraction is....
Muscle contraction is the activation of tension-gathering sites within muscle fibers. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length such as holding a heavy book or dumbbell at the same position.
Myoglobin can bind to only one molecule of oxygen because...
Myoglobin can bind to only one molecule of oxygen since it contains only one heme group.
Myoglobin is...
Myoglobin is a globular protein that is found in skeletal muscle and cardiac muscle in all vertebrates and mammals. Myoglobin has a higher oxygen affinity than hemoglobin. Myoglobin stores oxygen and uses it as a reserve for when the demand for oxygen cannot be adequately met by hemoglobin. High amounts of myglobin allow organisms to hold their breath for an extended time under water...think whales and seals! Myoglobin has oxygen bound on a heme group found on its single polypeptide chain. Most of the molecule of hemoglobin is alpha helix (80%). Since it is a mono of 1 chain, it has no quaternary structure. The folding of the myoglobin (Mb) chain places the nonpolar residudes interior, where they are shielded from water. Many polar amino acid residues reside on the outside, making Hb a water-soluble globular protein. Remember: Globular proteins=hydrophilic and water soluble. The heme group (prosthetic group...nonprotein part) sits on a crevice lined by nonpolar amino acids.
Myoglobin is found..
Myoglobin is found in the cytosol of cardiac and skeletal muscle cells. It obtains oxygen from the vessels that supply oxygenated blood to these cells. Therefore, myoglobin receives oxygen from oxyhemoglobin (HbO₂). This is because myoglobin has a much higher affinity for oxygen than hemoglobin does.
Hemoglobin Vs. Myoglobin cooperativity....
Myoglobin is like hemoglobin; however, it is a single peptide that has just one heme cofactor. So, it does not experience cooperativity like hemoglobin would, but it saturates quickly. It has a hyperbolic curve, whereas hemoglobin has a sigmoidal curve (S shaped curve). These curves tell us that myoglobin holds onto oxygen tigher and with a higher affinity
_______ is the heme iron containing protein responsible for the color of meat. The more ____ the darker red the meat!! Older animals have more _____...thus the meat is darker!
Myoglobin is the heme iron containing protein responsible for the color of meat. The more myoglobin the darker red the meat! Older animals have more myoglobin, thus the meat is darker!
High amounts of __________ allow organisms to hold their breath for an extended time under water
Myoglobin stores oxygen and uses it as a reserve for when the demand for oxygen cannot be adequately met by hemoglobin. High amounts of myglobin allow organisms to hold their breath for an extended time under water...think whales and seals!
This is how the bicarbonate Buffer System works.....
NOTION
Pathway of air....
Nasal Cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
intrapleural or thoracic negative pressure is.....
Negative pressure is when a certain ventilation generates negative pressure to allow air to flow into the isolated area but not escape that area, as air will naturally flow from areas with higher pressure to areas with lower pressure, thereby preventing contaminated air from escaping the area. Hence in the lungs, since it has a negative pressure in the pleural space (namely intrapleural or thoracic negative pressure), air from the atmosphere which is higher brings air into the pleural space which holds a lower pressure. In this way air can come into the pleural space, but it cannot escape the pleural space, and this is what holds the lungs up and doesn't allow it to collapse on itself.
Chemoreceptors...
Now remember that chemoreceptors can tell if the blood is acidic or not. Chemoreceptors send signals to the medulla which can respond with increasing the breathing rate.
Peripheral Chemoreceptors...
Now remember that the central nervous system consists of the brain and spinal cord, the peripheral nervous systems takes care of the division of the nervous system containing all the nerves that lie outside of the CNS. The primary role of the PNS is to connect the CNS to the organs, limbs, and skin. Peripheral chemoreceptors are located in 'bodies' that surround the aortic arch and carotid arteries (carotid arteries branch off the aorta). Carotid Arteries branch off the aorta and supply oxygenated blood to the head and neck. Peripheral chemoreceptors are not protected by the blood brain barrier. Mnemonic: peripheral chemoreceptors are in the peripheral nervous system. Peripheral chemoreceptors detect changes in the concentrations of oxygen, carbon dioxide, and protons (H⁺) in arterial blood. Carbon dioxide is high when arterial oxygen is low. This means that proton levels are also high, due to the activity of carbonic anhydrase. These changes stimulate the peripheral chemoreceptors, which utilize sensory nerve to send signals back to the medulla oblongata. Here, the medulla oblongata will send signals to the respiratory muscles (mainly the diaphragm) that cause us to breathe faster.
Medulla Oblongata...
Now remember that the medulla oblongata helps to regulate functions such as breathing, heart rate, swallowing, and digestion. It is the "center for respiration and circulation". It is involved in many involuntary functions. It contains myelinated and nonmyelinated fibers. The Medulla oblongata houses cardiac, respiratory, and even sneezing and vomiting centers are all located here.
_____________ send signals to the medulla which can respond with increasing the breathing rate.
Now remember, chemoreceptors can tell if the blood is acidic or not (they are very sensitive to pH and even temperature changes). Chemoreceptors send signals to the medulla which can respond with increasing the breathing rate.
One of the roles in the liver is erythrocyte destruction by special cells called Kupffer Cells...how does this process work?
One of the roles of the liver is erythrocyte destruction, where old or useless red blood cells are destroyed by special cells called Kupffer cells. Since erythocytes contain hemoglobin (red pigmented), the hemoglobin is broken down by Kupffer cells into billirubin (yellowish pigment). Billirubin is secreted into bile (that's why bile has a yellowish-green color!) Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down fats into fatty acids, which can be taken into the body by the digestive tract. The liver then sends bile to the gallbladder for storage and ultimate secretion. When fats from the stomach go down into the small intestine, specifically the duodenum, it signals the gallbladder to release this bile component. Bile helps emulsify these fats into small fat droplets so they can be easier to digest and absorb. Bile is NOT an enzyme, emulsification is a type of mechanical digestion - not enzymatic breakdown! Any of the leftover bile is excreted via defecation.
Plants use ___________to exchange gases involved in photosynthesis and respiration with the atmosphere.
Plants use pores to exchange gases involved in photosynthesis and respiration with the atmosphere. The pores found on the bottom of a plant's leaves are called stomata, whereas lenticels are the pores found on woody tree stems. Loosely packed soil has pockets of air, this is why roots also contain pores that allow gas exchange to occur.