Respiratory Physiology
... Ventilation is uneven within the lungs •The weight of the lungs produces uneven inflation of alveoli. Lungs weight make different alveolar volume at the top and bottom of the lungs (e.g. alveoli at the top of the lungs are at a larger volume (more negative intrapleural pressure) than those at the b ...
... Ventilation is uneven within the lungs •The weight of the lungs produces uneven inflation of alveoli. Lungs weight make different alveolar volume at the top and bottom of the lungs (e.g. alveoli at the top of the lungs are at a larger volume (more negative intrapleural pressure) than those at the b ...
Respiratory physiology
... pressures, a compliance curve for the lung can be constructed. The slope of this plot is lung compliance. Normally, lung compliance is measured under static conditions, meaning no airflow is present at the time the relaxation (recoil) pressure is measured. Effect of thoracic cage Compliance of both ...
... pressures, a compliance curve for the lung can be constructed. The slope of this plot is lung compliance. Normally, lung compliance is measured under static conditions, meaning no airflow is present at the time the relaxation (recoil) pressure is measured. Effect of thoracic cage Compliance of both ...
RESPIRATION
... Once it is across the BBB, CO2 + H2O H2CO3 H+ + HCO3These increased H+ ions in the brain stimulate the medullary chemoreceptors. ...
... Once it is across the BBB, CO2 + H2O H2CO3 H+ + HCO3These increased H+ ions in the brain stimulate the medullary chemoreceptors. ...
Bile secretion
... Provided by secretory glands which serve 2 functions: - Digestive enzymes. - Lubrication and protection of the mucosa. ...
... Provided by secretory glands which serve 2 functions: - Digestive enzymes. - Lubrication and protection of the mucosa. ...
1. In which of the following fluids is the pH highest (most alkaline
... metabolic alkalosis can be complete 4. The appearance of large amounts of ammonium ion (NH4+) in the urine is characteristic of the renal response to A. B. C. D. E. ...
... metabolic alkalosis can be complete 4. The appearance of large amounts of ammonium ion (NH4+) in the urine is characteristic of the renal response to A. B. C. D. E. ...
Pulmonary Ventilation: Inspiration and Expiration
... lungs would tend to collapse. It is extremely important, therefore, that the type II alveolar cells secrete a detergent-like substance known as pulmonary surfactant, which markedly reduces the cohesive forces between water molecules on the alveolar surface. Therefore, surfactant lowers the surface t ...
... lungs would tend to collapse. It is extremely important, therefore, that the type II alveolar cells secrete a detergent-like substance known as pulmonary surfactant, which markedly reduces the cohesive forces between water molecules on the alveolar surface. Therefore, surfactant lowers the surface t ...
2. Physiology_Respiratory_System
... and the cilia, which are covered by mucus, beat in a co-ordinated fashion at a frequency of 1000-1500 cycles per minute. ♦ The ciliary mechanism is capable of moving particles away from the lungs at a rate of at least 16mm/min. Particles less than 2µm in diameter generally reach the alveoli, where t ...
... and the cilia, which are covered by mucus, beat in a co-ordinated fashion at a frequency of 1000-1500 cycles per minute. ♦ The ciliary mechanism is capable of moving particles away from the lungs at a rate of at least 16mm/min. Particles less than 2µm in diameter generally reach the alveoli, where t ...
CHAPTER 1 Anatomy and physiology of the human respiratory system
... Number of Alveoli (millions) ...
... Number of Alveoli (millions) ...
If we regard the alveoli as spherical bubles, then - Lectures For UG-5
... Importance of Surfactant • Reduces the tendency of alveoli to collapse by reducing surface tension • Reduces work of breathing by increasing lung compliance • Prevents pulmonary oedema • Responsible for alveolar stabilization ...
... Importance of Surfactant • Reduces the tendency of alveoli to collapse by reducing surface tension • Reduces work of breathing by increasing lung compliance • Prevents pulmonary oedema • Responsible for alveolar stabilization ...
Introduction to Autonomic Pharmacology
... • The effect of ACh binding: – Can be either inhibitory or excitatory – Depends on the receptor type of the target organ ...
... • The effect of ACh binding: – Can be either inhibitory or excitatory – Depends on the receptor type of the target organ ...
regular course syllabus
... Specific (Measurable) Student Behavioral Learning Objectives (format: 1, a, i, ii, etc.): ...
... Specific (Measurable) Student Behavioral Learning Objectives (format: 1, a, i, ii, etc.): ...
Respiratory Physio Detailed File
... during inspiration; pressure increases during expiration. Intrapleural pressure. Pleural cavity pressure ...
... during inspiration; pressure increases during expiration. Intrapleural pressure. Pleural cavity pressure ...
Membrane Biophysics and Synaptic Physiology
... dependence of release, two models and mechanisms? •Multivesicular release, when and where? •Synaptic ...
... dependence of release, two models and mechanisms? •Multivesicular release, when and where? •Synaptic ...
Acid-Base_Handling
... – Low filtered [Cl-] increases H+ secretion • Cl- is passively cosecreted with H+ secretion via H+ATPase to maintain electroneutrality thus ability to secrete H+ is enhanced with low tubular fluid [Cl-] • In setting of low tubular fluid [Cl-], Na+ reabsorption must be accompanied by H+ or K+ secreti ...
... – Low filtered [Cl-] increases H+ secretion • Cl- is passively cosecreted with H+ secretion via H+ATPase to maintain electroneutrality thus ability to secrete H+ is enhanced with low tubular fluid [Cl-] • In setting of low tubular fluid [Cl-], Na+ reabsorption must be accompanied by H+ or K+ secreti ...
homeostasis - advbiology227
... _____________________________________________________________ In general, what effect does positive feedback have on homeostasis? _____________________________________________________________ ...
... _____________________________________________________________ In general, what effect does positive feedback have on homeostasis? _____________________________________________________________ ...
Saladin 5e Extended Outline
... d. The most numerous of all cells in the lung are alveolar macrophages (dust cells). i. These cells keep the alveoli free of debris by phagocytizing dust particles that escape entrapment by mucus. ii. In lungs that are infected or bleeding, they also phagocytize bacteria and loose blood cells. iii. ...
... d. The most numerous of all cells in the lung are alveolar macrophages (dust cells). i. These cells keep the alveoli free of debris by phagocytizing dust particles that escape entrapment by mucus. ii. In lungs that are infected or bleeding, they also phagocytize bacteria and loose blood cells. iii. ...
Special Senses - Everglades High School
... the nasal cavity, which is why “sniffing” intensified the smell, because more air is forced to the top of the cavity, stimulating the receptors. ...
... the nasal cavity, which is why “sniffing” intensified the smell, because more air is forced to the top of the cavity, stimulating the receptors. ...
Packet 23
... 5. Iodine is then added to the TYROSINE molecules ON the thyroglobulin. A. Sometimes 1 iodide is added...other times 2 iodides are added B. Everything is STILL a thyroglobulin molecule… 6. Now the 1 and 2 iodide molecules COMBINE in varying ways… A. 1+2 = 3 (triiodothyronine, or T3) B. 2+2 = 4 ...
... 5. Iodine is then added to the TYROSINE molecules ON the thyroglobulin. A. Sometimes 1 iodide is added...other times 2 iodides are added B. Everything is STILL a thyroglobulin molecule… 6. Now the 1 and 2 iodide molecules COMBINE in varying ways… A. 1+2 = 3 (triiodothyronine, or T3) B. 2+2 = 4 ...
BIOLOGY 102 COURSE OBJECTIVES
... (2) Compare Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms on the basis of (a) vascular or nonvascular, (b) spore or seed-producers, (c) flower or fruit production; and give several examples of each. (3) Among angiosperms, compare monocots to dicots. UNIT IV (1) Compare the following basic ...
... (2) Compare Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms on the basis of (a) vascular or nonvascular, (b) spore or seed-producers, (c) flower or fruit production; and give several examples of each. (3) Among angiosperms, compare monocots to dicots. UNIT IV (1) Compare the following basic ...
Respiratory System (Power Point Document)
... SURFACTANTDEFINATION- Any surface acting material or agent that is responsible for lowering surface tension of fluid is called surfactant. The surfactant present in the alveoli of lungs is called as pulmonary surfactant. It is a complex detergent like mixture of phospholipids and lipoproteins. It i ...
... SURFACTANTDEFINATION- Any surface acting material or agent that is responsible for lowering surface tension of fluid is called surfactant. The surfactant present in the alveoli of lungs is called as pulmonary surfactant. It is a complex detergent like mixture of phospholipids and lipoproteins. It i ...
Pathophysiology and treatment of alveolar–capillary dysfunction in
... clearance and capillary fluid reabsorption. Pulmonary abnormalities and, specifically those in gas-diffusion capacity, can explain part of the symptoms and functional limitation encountered in HF. Notably, Dm at rest and relative changes on exertion correlate with O2 uptake at peak exercise [18,34]. ...
... clearance and capillary fluid reabsorption. Pulmonary abnormalities and, specifically those in gas-diffusion capacity, can explain part of the symptoms and functional limitation encountered in HF. Notably, Dm at rest and relative changes on exertion correlate with O2 uptake at peak exercise [18,34]. ...
No Slide Title
... • The activity of the upper airway muscles (nose, pharynx and larynx) also decreases during sleep. • The negative pressure during inspiration is normally counterbalanced by activity of the upper airway muscles that function to keep the upper airway open. • Inspiration tends to collapse the upper air ...
... • The activity of the upper airway muscles (nose, pharynx and larynx) also decreases during sleep. • The negative pressure during inspiration is normally counterbalanced by activity of the upper airway muscles that function to keep the upper airway open. • Inspiration tends to collapse the upper air ...
Alveolar macrophage
An alveolar macrophage (or dust cell) is a type of macrophage found in the pulmonary alveolus, near the pneumocytes, but separated from the wall.Activity of the alveolar macrophage is relatively high, because they are located at one of the major boundaries between the body and the outside world.Dust cells are another name for monocyte derivatives in the lungs that reside on respiratory surfaces and clean off particles such as dust or microorganisms.Alveolar macrophages are frequently seen to contain granules of exogenous material such as particulate carbon that they have picked up from respiratory surfaces. Such black granules may be especially common in smoker's lungs or long-term city dwellers.Inhaled air may contain particles or organisms which would be pathogenic. The respiratory pathway is a prime site for exposure to pathogens and toxic substances. The respiratory tree, comprising the larynx, trachea, and bronchioles, is lined by ciliated epithelia cells that are continually exposed to harmful matter. When these offensive agents infiltrate the superficial barriers, the body's immune system responds in an orchestrated defense involving a litany of specialized cells which target the threat, neutralize it, and clean up the remnants of the battle. Deep within the lungs exists its constituent alveoli sacs, the sites responsible for the uptake of oxygen and excretion of carbon dioxide. There are three major alveolar cell types in the alveolar wall (pneumocytes): Type I pneumocyte (Squamous Alveolar) cells that form the structure of an alveolar wall. Type II pneumocyte (Great Alveolar) cells that secrete pulmonary surfactant to lower the surface tension of water and allows the membrane to separate, thereby increasing the capability to exchange gases. Surfactant is continuously released by exocytosis. It forms an underlying aqueous protein-containing hypophase and an overlying phospholipid film composed primarily of dipalmitoyl phosphatidylcholine. Macrophages that destroy foreign material, such as bacteria.Type 1 and type 2 pneumocytes. Type 1 pneumocytes (or membranous pneumocytes) form the structure of the alveolus and are responsible for the gas exchange in the alveolus. Type 1 pneumocytes are squamous epithelial cells which are characterized by a superficial layer consisting of large, thin, scale-like cells; they also cover 95% of the alveolar surface, although they are only half as numerous as Type 2 pneumocytes. Type 2 pneumocytes are important in that they can proliferate and differentiate into type 1 pneumocytes, which cannot replicate and are susceptible to a vast numbers of toxic insults. Type 2 pneumocytes are also important because they secrete pulmonary surfactant(PS), which consists 80-90% of phospholipids [(phosophatidylcholine(PC), phosphatidyglycerol(PG), phosphaditylinositol (PI)] and 5-10% of surfactant proteins (SP-A, SP-B, SP-C, AND SP-D). PS is synthesized as lamellar bodies, which are structures consisting of closely packed bilayers that are secreted and then undergo transformation into a morphological form called tubular myelin. PS plays an important role in maintaining normal respiratory mechanics by reducing alveolar surface tension. By lowering alveolar surface tension, PS reduces the energy required to inflate the lungs, and reduces the likelihood of alveolar collapse during expiration. Loosely attached to these alveoli sacs are the alveolar macrophages that protect the lungs from a broad array of microbes and aerosols by devouring and ingesting them through phagocytosis.Alveolar macrophages are phagocytes that play a critical role in homeostasis, host defense, the response to foreign substances, and tissue remodeling. Since alveolar macrophages are pivotal regulators of local immunological homeostasis, their population density is decisive for the many processes of immunity in the lungs. They are highly adaptive components of the innate immune system and can be specifically modified to whatever functions needed depending on their state of differentiation and micro-environmental factors encountered. Alveolar macrophages release numerous secretory products and interact with other cells and molecules through the expression of several surface receptors. Alveolar macrophages are also involved in the phagocytosis of apoptotic and necrotic cells that have undergone cell-death. They must be selective of the material that is phagocytized because normal cells and structures of the body must not be compromised. To combat infection, the phagocytes of the innate immune system facilitates many pattern recognition receptors (PRR) to help recognize pathogen-associated molecular patterns (PAMPs) on the surface of pathogenic microorganisms. PAMPs all have the common features of being unique to a group of pathogens but invariant in their basic structure; and are essential for pathogenicity(ability of an organism to produce an infectious disease in another organism). Proteins involved in microbial pattern recognition include mannose receptor, complement receptors, DC-SIGN,Toll-like receptors(TLRs), the scavenger receptor, CD14, and Mac-1. PRRs can be divided into three classes:signaling PRRs that activate gene transcriptional mechanisms that lead to cellular activation,endocytic PRRs that function in pathogen binding and phagocytosis, andsecreted PRRs that usually function as opsonins or activators of complement.The recognition and clearance of invading microorganisms occurs through both opsonin-dependent and opsonin–independent pathways. The molecular mechanisms facilitating opsonin-dependent phagocytosis are different for specific opsonin/receptor pairs. For example, phagocytosis of IgG-opsonized pathogens occurs through the Fcγ receptors (FcγR), and involves phagocyte extensions around the microbe, resulting in the production of pro-inflammatory mediators. Conversely, complement receptor-mediated pathogen ingestion occurs without observable membrane extensions (particles just sink into the cell) and does not generally results in an inflammatory mediator response. Following internalization, the microbe is enclosed in a vesicular phagosome which then undergoes fusion with primary or secondary lysosomes, forming a phagolysosome. There are various mechanisms that lead to intracellular killing; there are oxidative processes, and others independent of the oxidative metabolism. The former involves the activation of membrane enzyme systems that lead to a stimulation of oxygen uptake (known as the respiratory burst), and its reduction to reactive oxygen intermediates (ROIs), molecular species that are highly toxic for microorganisms. The enzyme responsible for the elicitation of the respiratory burst is known as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which is composed of five subunits. One component is a membrane cytochrome made up of two protein subunits, gp91phox and p22phox; the remaining three components are cytosolic-derived proteins: p40phox, p47phox, and p67phox. NADPH oxidase exists in the cytosol of the AM when in a quiescent state; but upon activation, two of its cytosolic components, p47phox and p67phox, have their tyrosine and serine residues phosphorylated, which are then able to mediate translocation of NADPHox to the cytochrome component, gp91phox/p22phox, on the plasma membrane via cytoskeletal elements.Compared to other phagocytes, the respiratory burst in AM is of a greater magnitude. Oxygen-independent microbicidal mechanisms are based on the production of acid, on the secretion of lysozymes, on iron-binding proteins, and on the synthesis of toxic cationic polypeptides. Macrophages possess a repertoire of antimicrobial molecules packaged within their granules and lysosomes. These organelles contain a plethora of degradative enzymes and antimicrobial peptides that are released into the phagolysosome, such as proteases, nucleases, phosphatases, esterases, lipases, and highly basic peptides. Moreover, macrophages possess a number of nutrient deprivation mechanisms that are used to starve phagocytosed pathogens of essential micronutrients. Certain microorganisms have evolved countermeasures which enable them to evade being destroyed by phagocytes. Although lysosomal-mediated degradation is an efficient means by which to neutralize an infection and prevent colonization, several pathogens parasitize macrophages, exploiting them as a host cell for growth, maintenance and replication. Parasites like Toxoplasma gondii and mycobacteria are able to prevent fusion of phagosomes with lysosomes, thus escaping the harmful action of lysosomal hydrolases. Others avoid lysosomes by leaving the phagocytic vacuole, to reach the cytosolic matrix where their development is unhindered. In these instances, macrophages may be triggered to actively destroy phagocytosed microorganisms by producing a number of highly toxic molecules and inducing deprivational mechanism to starve it. Finally, some microbes have enzymes to detoxify oxygen metabolites formed during the respiratory burst.When insufficient to ward off the threat, alveolar macrophages can release proinflammatory cytokines and chemokines to call forth a highly developed network of defensive phagocytic cells responsible for the adaptive immune response. The lungs are especially sensitive and prone to damage, thus to avoid collateral damage to type 1 and type II pneumocytes, alveolar macrophages are kept in a quiescent state, producing little inflammatory cytokines and displaying little phagocytic activity, as evidenced by downregulated expression of the phagocytic receptor Macrophage 1 antigen (Mac-1). AMs actively suppress the induction of two of the immunity systems of the body: the adaptive immunity and humoral immunity. The adaptive immunity is suppressed through AM’s effects on interstitial dendritic cells, B-cells and T-cells, as these cells are less selective of what they destroy, and often cause unnecessary damage to normal cells. To prevent uncontrolled inflammation in the lower respiratory tract, alveolar macrophages secrete nitric oxide, prostaglandins, interleukin-4 and -10(IL-4, IL-10), and transforming growth factor-β (TGF-β).