233 Lecture 1 Flashcards
Explain the difference between specific and nonspecific defenses
Innate (nonspecific) immunity - Physical barriers and internal defense processes that either prevent or slow the entry of infectious organisms, or attack them if they do enter. Skin and phagocytes for example. Innate because things that a person is born with. Is not particular on what foreign pathogen it is and depends on the NK cells
Adaptive (specific) immunity - two classes of lymphocytes, T cells and B cells, respond to specific antigens. There is cells of each for specific bacteria or virus and only attack that one it is programed to recognize.
Describe the two main functions of the lymphatic system
To return the lymph fluid and returning lymph.
And to a immune response.
Describe the characteristics and location of lymphatic capillaries, small lymphatic vessels, and major lymph-collecting vessels.
- lymphatic capillaries - Beginning of the lymphatic network. Closed at one end, large luminal diameters, thin walls, and typically have a flattened or irregular outline in sectional view. Lined with endothelial cell, incomplete or absent basement membrane. Cells are not bound tightly, but overlap, which acts as a one way valve. Permits fluid and routes to enter but prevents them from returning to the intercellular spaces.
- small lymphatic vessels - capillaries flow into larger lymphatic vessels that lead towards the body’s trunk. The walls contain 3 layers. They contain valves that are quite close together, and produce a noticeable bulges (making it bead like appearance). Contractions of skeletal muscles surrounding the vessels aid lymph flow.
- major lymph-collecting vessels - 2 sets, superficial lymphatics and deep lymphatic’s. Superficial are in the subcutaneous layer deep to the skin (areolar tissues of the mucous membranes lining the digestive, respiratory, urinary, and reproductive tracts. Deep lymphatics are larger lymphatic vessels that accompany deep arteries and veins supplying skeletal muscles and other organs of the neck, limbs, and trunk, and the walls of visceral organs.
List the three types of lymphocytes, and briefly describe their function
T (thymus-depended) cells, B (bone marrow-derived) cells, and NK (natural killer) cells. Each has a distinctive biochemical and functional properties. Lymphocytes respond to specific invading pathogens, as well as to abnormal body cells (such as virus-infected cells or cancer cells) and foreign proteins (such as virus-infected cells or cancer cells) and foreign proteins (such as the toxins released by some bacteria).
Explain the process and structures involved in lymphocyte production
Lymphocytopoiesis is the lymphocyte formation which involves the red bone marrow, thymus and peripheral lymphoid tissues. Hemocytoblasts divide in the red bone marrow to generate the lymphoid stem cells that produce all types of lymphocytes. The red bone marrow produces two distinct populations of lymphoid stem cells. One stays in the bone marrow which the other migrates to the thymus. They one that stays in the bone marrow divide to produce immature B cells and NK cells. As they mature, the B and NK cells enter the bloodstream and migrate to peripheral tissues. Most of the B cells move into lymph nodes, spleen and other lymphoid tissues. The NK cells patrol the body.
The second group of stem cells that end up in the thymus develop and mature in there that is isolated from general circulation by the blood thymus barrier. The cell divides in to various types of T cells, and when development is near completion they reenter the blood stream and travel to peripheral tissues.
Describe and differentiate between lymphoid nodules, MALT, and tonsils
- Lymphoid nodules, or lymphatic nodule, are densely packed in an area of areolar tissue. Its boundaries are not distinct, because no fibrous capsule surrounds it. Each nodule often has a central zone called a germinal center, which contains dividing lymphocytes
- MALT - (mucosa-associated lymphoid tissue) collection of lymphoid tissues that protect the epithelia of the digestive, respiratory, urinary, and reproductive system. Clusters deep to the epithelial lining of the intestine are aggregated lymphoid nodules (Peyer’s patches), others include appendix and tonsils.
- Tonsils - large lymphoid nodules in the walls of the pharynx. Most people have 5; one pharyngeal tonsil (adenoid), 2 palatine tonsils posterior and inferior margin of the oral cavity, and a 2 of the lingual tonsils mucous epithelium covering the base of the tongue.
Describe and understand the structure and function of lymph nodes
Lymph nodes are small lymphoid organs ranging in diameter from 1mm to 25 mm. The greatest number are located in the neck (cervical), axillae (axillary), and groin (iguinal) lymph nodes. They defend us against bacteria and other invaders. It flows from many vessels out very few to allow the lymph fluid to be filtered throughly. Early warning system, any abnormality in the peripheral tissue puts antigens into the interstitial fluid, and thus into the lymph leaving the area. Allowing the antigens to stimulate macrophages and lymphocytes in the lymph node. Pathogen antigens are also carried by dendritic cells to the the local lymph node to stimulate a programed T or B cell into action.
Describe and understand the structure and function of the thymus
- Thymus is a pink, grainy organ located in the mediastinum posterior to the sternum. It is very large in infants and young children and reaches maximum size just before puberty. After puberty it gradually diminishes through life it turns more smaller and more fibrous. This is after all the T cells needed are created. The capsule of the thymus divides into two thymus lobes, fibrous partitions, septa, originate in the capsule and divide the lobes into lobules. Each lobule consists of an outer cortex densely packed with lymphocytes and a paler, central medulla.
- Function - the cortex contains actively dividing T cell lymphocytes.Epithelial reticular cells maintain the blood thymus barrier. Regulates the T cell development and function. Maturing T cells leave the cortex and enter the medulla of the thymus (where there is no blood thymus barrier). T cells then enter the bloodstream into the blood vessels or lymph vessels.
Describe and understand the structure and function of the spleen
The spleen contains the largest collection of lymphoid tissue in the body and preforms the same functions as the lymph nodes. Functions are removing abnormal blood cells and other blood components by phagocytosis, storing iron recycled from red blood cells, and initiating immune responses by B cells and T cells in response to antigens in circulating blood.
The spleen Is about 12 cm and weighs about 160 g. Red, due to the blood it contains.It lies along the curving lateral border of the stomach, extending between the 9th and 11th ribs on the left side, and attached to the lateral border of the stomach by the gastrosplenic ligament, a broad band of mesentery. A soft structure and if damaged can not be repaired. Contains red pulp (large quantities of red blood) and white pulp (resembles lymphoid nodules and contains a high concentration of lymphocytes and dendritic cells)
Describe the components and mechanisms for each nonspecific defense
- Physical barriers - Skin and mucous membrane, or epithelium, protects the outside body from pathogens. It is the first line of defense.
- Phagocytes serve as janitors and police in peripheral tissues. They remove cellular debris and respond to invasion by foreign substances or pathogens. Many phagocytes attack and remove microorganisms even before lymphocytes detect them. The human body has two general classes of phagocytes: microphages and macrophages.
- Immunological surveillance - The immune system ignores the body’s own cells unless they become abnormal in some way. NK cells are responsible for recognizing and destroying abnormal cells. This continuous “policing” of peripheral tissues is the immune surveillance.
- Interferon - are small proteins released by activated lymphocytes and macrophages, and by tissue cells infected with viruses. This warns the infected neighbors
- Complement - Antibacterial. The activation can occur in 3 different routes: Classic, lectin, and the alternative pathway.
- Inflammatory response - is a localized tissue response to injury. Redness, swelling, heat, and pain. Stimuli that produce inflammation (impact, abrasion, infection by pathogen, ect.) kills cells, damage connective tissue fibers, or injures the tissue in some other way.
- Fever - is a body temperature greater than 37.2 degrees celsius. The hypothalamus controls the temperature with agents called pyrogens which can reset this thermostat and raise body temperature.
Pathways of Complement Activation
- Classical pathway - the most rapid and effective activation of the complement system occurs.
1. antibodies bind to bacterial cell wall
2. attachement of C1 to two antibodies
3. Activation and cascade - C1 acts as an enzyme, that split C3 into C3a and C3b.
4. C3b binds to the bacterial wall and enhances phagocytosis. - lectin pathway - ends in attachemtn of C3b
- alternative pathway - ends in attachemtn of C3b
They all cause killing of pathogen (cell lysis), enhances phagocytosis (opsonization), and inflammation (histamine release).
Define specific resistance (immunity) and identify the different forms of immunity
- Adaptive (specific) resistance (immunity) - result from the coordinated activities of T lymphocytes (T cells) and B lymphocytes (B cells). Under stimulation T cells differentiate into several types of cells, which attack antigens and help to increase the immune response. They include Cytotoxic T cells (involved in direct cellular attack. These cells enter peripheral tissues and attack antigens physically and chemically), Helper T cells ( are absolutely vital to the immune response because they stimulate the responses of both T cells and B cells, especially they must activate the B cells before B cells can produce antibodies), regulatory T cells (a subset of T cells that moderate the immune response), and memory T cell (respond to antigens they have already encountered by the cloning of more lymphocytes to ward off the invader).
- Forms of adaptive immunity - can be active or passive. Active immunity develops after exposure to an antigen (Naturally acquired active immunity, Artificially acquired active immunity). Passive immunity is produced by transferring antibodies from another source (naturally acquired passive immunity, and artificially acquired passive immunity)
Describe and understand the four general properties of immunity.
Adaptive immunity has four general properties: (1) specificity, (2) versatility, (3) memory, and (4) tolerance.
* Specificity - results from the activation of appropriate lymphocytes and the production of antibodies with targeted effects. It occurs because T cells and B cells respond to the molecular structure of an antigen. Each antigen is specific shape and size.
* Versatility - since it must be ready to confront any antigen at any time, the versatility is the large diversity of lymphocytes present in the body, and in part from variability in the structure of synthesized antibodies
* Memory - exists because those cell divisions produce two groups of cells. One group attacks the invaders immediately, while another group remains inactive unless it meets the same antigen at a later date.
* Tolerance - is a tolerance toward self-antigens
Describe and understand the process of antigen presentation
Once T cells are activated by exposure to an antigen a immune response can be used.T cells only recognize antigens when they are processed and “presented” by cells called antigen-presenting cells, most of them are phagocytes such as macrophages. The antigen presentation is the first step in the activation of the immune response.
Antigen presentation is the expression of antigen molecules on the surface of a macrophage or other antigen-presenting cell in association with MHC class II molecules when the antigen is being presented to a CD4+ helper T cell or in association with MHC class I molecules when presentation is to CD8+ cytotoxic T cells.
Differentiate between Class I MHC proteins and Class II MHC proteins
- All cells have a Class I MHC proteins and when it is normal it doesn’t cause any fuss but if it is infected or cancerous it starts presenting a weird proteins signaling that it needs to be killed by NK cells.
- Class II MHC proteins are only present in the plasma membranes of antigen-presenting cells (APCs) and
Describe and understand the process of antigen recognition
Inactive T cells have receptors that can bind either class I or II MHC proteins. These receptors also have binding sites for a specific target antigen. If a MHC protein contains any antigen other than the specific target antigen.
Differentiate between CD8 markers and CD4 markers
- CD8 markers are found on cytotoxic T cells and regulatory T cells, which together are often called CD8 Cells. CD8 T cells respond to antigens presented by class I MHC proteins.
- CD4 markers are found on helper T cells, often called CD4 T cells. CD4 T cells respond to antigens presented by class II MHC proteins.
Describe costimulation
Costimulation is like the safety on a gun: It helps prevent T cells from mistakenly attacking normal (self) tissues. Before activation can occur, a T cell must be chemically or physically stimulated by the abnormal target.
Describe and understand the processes of CD8 and CD4 T cell activation
Antigen recognition occurs when a CD8 T cell encounters an appropriate antigen on surface of another cell, bound to a class I MHC protein. Activation and cell division - antigen recognition and costimulation result in T cell activation and cell division, producing active Tc cells and memory Tc cells. Destruction of target cell - the active Tc cell destroys the antigen-bearing cell. It may use several different mechanisms to kill the target cell. Will either release perforin (destruction of plasma membrane), cytokine (stimulation of apoptosis), or lymphotoxin (disruption of cell metabolism).
Describe and understand the processes of CD4 T cell activation
Antigen recognition from a APC by CD4 T cell this activates the helper T cell (TH) to divide, which makes memory TH and active TH cells which secrete cytokines that stimulate both cell-mediated and antibody-mediated immunity. This (1) stimulate the T cell divisions, Enhance nonspecific defenses by attracting macrophages, attract and stimulate the activity of cytotoxic T cells, and promote the activation of B cells (leading to antibody production).
Describe the process of B cell sensitization and activation
A B cell is sensitized by exposure to antigens. Once antigens are bound to antibodies in the B cell plasma membrane, the B cell displays those antigens on class II MHC proteins in its plasma membrane. Activated helper T cells encountering the antigens release cytokines that costimulate the sensitized B cell and trigger its activation. The activated B cell then divides, producing memory B cells and plasma cells that secrete antibodies.
Describe general antibody structure
A Y-shaped antibody molecule consists of two pairs of polypeptide chains: one pair of heavy chains and one pair of light chains. Both contains constant segments and variable segments. They contain disulfide bonds that hold it together, Site of binding to macrophages, complement binding sites, and antigen-binding site.
Differentiate between the 5 classes of antibodies and their actions
- IgG - (free floating)the largest and most diverse. Hymolytic disease of the newborn.
- IgE - (attached to cells) bound to the surface of basophils and mast cells. Releases histamine and other chemicals that accelerate inflammation. Important in allergic response.
- IgD - (attached to cells) on the surface of the B cells. This binding plays a role in the sensitization of the B cell involved
- IgM - (free floating) is the first class of antibody secreted after an antigen arrives. Although plasma cells secrete individual IgM molecules, IgM circulates as a five-antibody starburst. The anti-A and anti-B antibodies are responsible for the agglutination of incompatible blood types.
- IgA - (free floating) has a secretory piece to allow it to be soluble. Found in glandular secretions such as mucus, tears, saliva, and semen. In the blood as individual molecules, and when the epithelial cells absorb them from the blood they attach a secretory piece, which confers solubility, then secretes it onto the epithelial surface.
Actions of antibodies
- Neutralization - antibodies bind to the specific sites on the pathogen making them incapable of attaching itself to a cell.
- Precipitation and agglutination - each antibody molecule has two antigen-binding sites. One for the pathogen the other for eachother. Once attached to a pathogen link in large numbers of antigens together.
- Activation of the complement system - non specific defenses. Classic, lectin, and alternative pathway: C1 complement protein, and activation to the C3b attachment.
- Attraction of phagocytes - atigens covered with antibodies attract eosinophils, neutrophils, and macrophages. Which are phagocytes that detroy foreign or abnormal plasma membranes.
- Opsoniztation - a coating of antibodies increases the efgectiveness of phagocytosis. Slick bacteria membranes/capsule, the antibodies make it easier for the phagocytes to adhere.
- Stimulation of inflammation
- Prevention of bacterial and viral adhesion - similar to nuetralization.
Distinguish between a primary and a secondary response to antigen exposure
- Primary Response - the initial immune response to an antigen. Takes time to develop because the antigen must activate the appropriate B cells. Takes about 2 weeks to develop peak antibody levels (titers). IgM and IgG antibody levels do not remain elevated.
- Secondary Response - when the antigen appears again and it triggers a more extensive and prolonged response. Has a very rapid increase in IgG antibody concentration and rises to levels much higher than those of the primary response. Antibody levels remain elevated for an extended period after the second exposure to the antig
Describe the structure of the respiratory mucosa
Consists of an epithelium and an underlying layer of areolar tissue. The lamina propria is the underlying layer of areolar tissue that supports the respiratory epithelium. The upper respiratory system, trachea, and bronchi, the lamina propria contains mucous glands that discharge their secretions onto the epithelial surface.
Pseudostratified ciliated comlumnar epithelium lines nasal cavity, superior portion of the pharynx, and superior portion of the lower respiratory system. A cuboidal epithelium with scattered cilia are in the smaller bronchioles.
Identify the organs and structures of the upper respiratory system and their functions
- Nose - the primary passageway for air entering. The vestibule contains coarse hairs that are to catch large particles (sand and sawdust).
- Nasal cavity - air passes through the superior middle and inferior nasal meatuses. This swirls the air, increasing the likely hood of catching any particles also warming and humidifying the incoming air.
- Sinuses - helps keep the surfaces of the nasal cavity moist and clean.
- Pharynx - Nasopharynx, oropharynx, and laryngopharynx. Moves air from the nasal cavity to the larynx.
Describe the structure of the larynx and discuss its role in normal breathing and in the production of sound
- allows us to produces sound. During swallowing the epiglottis fold back over the glottis, preventing both liquids and solid food from entering the respiratory tract.
- contains 3 pairs of smaller hyaline cartilages (1) arytenoid cartilage, (2) the corniculate cartilage, (3) and an elongated curving cuneiform cartilage.
Discuss the structure of the airways outside the lungs (trachea)
- The trachea is a tough flexible tube. Begins anterior to vertebra C6 and ends T5, where it branches to form the left and right main bronchi.
- There is a muscle on the back side called the trachealis muscle
Discuss the structure of the airways outside the lungs (primary bronchi)
- Primary bronchi is the tube from the trachea to the terminal bronchiole right before respriatory zone (respriatory bronchiole).
- The walls of the main, lobar, and segmental bronchi conain progressively less cartilage. In the lobar and segmental bronchi, the cartilages form plates arranged around the lumen. The cartilage decreases and the amount of smooth muscle increases.
Describe the superficial anatomy of the lungs and the structure of a pulmonary lobule.
Describe the structures of the bronchioles, alveolar ducts, and alveoli.
Cells in the alveolar:
* Pneumocyte type I is a thin and the site of gas diffusion.
* Pneumocyte type II are large and scattered among the squamous cells. They produce surfactant.
* Alveolar macrophages
Describe the pathway of air from the mouth to alveoli.
Through the upper respiratory system: nose, nasal vestibule, nasal cavity, nasal conchae, the pharynx (nasopharynx, oropharynx, laryngopharynx).
To the lower respiratory system: larynx (past the epiglottis, through the glottis) down the trachea, to the main bronchi, then lobar bronchi, segmental bronchi, smaller bronchi, bronchioles, terminal bronchiole, respiratory bronchiole, alveolar duct, alveolar sac, and last the alveoli.
Describe the blood supply to the lungs (pulmonary and systemic blood flow)
- Pulmonary circulation moves blood between the heart and the lungs. It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart. Systemic circulation moves blood between the heart and the rest of the body.
- The gas exchange occurs across the three-layered blood air barrier of the alveoli. The barrier is (1) the alveolar cell layer, (2) the capillary endothelial layer, (3) and the fused basement membrane between them.
Identify the functions of the pleura and pleural fluid
The two pleural cavities are spearated by the mediastinum. Each lung is surrounded by a single pleural cavity, which is lined by a serous membrane called the pleura. The pleura consists of two layers: the parietal pleura and the visceral pleura. The parietal pleura covers the inner surface of the thoracic and extends over the diaphragm and mediastinum. The visceral pleura covers the outer surface of the lungs, extending into the fissures between the lobes. Both pleurae secrete a small amount of pleural fluid, a moist slippery coating that lubricates. It reduces friction between the parietal and visceral surfaces as you breathe.
Understand the relationship between pressure and volume (Boyle’s Law)
- The relationship between gas pressure and volume.
- Same amount of gas in different shaped containers will have different pressure.
- Increase the volume decreases the pressure since the molecules are not bouncing into each other as often.
- Decrease the volume increases the pressure since the molecules are bouncing off each other more often.
- Atmospheric pressure is 760mmHg, when we breath in the lung “container” increase which decreases the pressure to 759mmHg pulling air in. When we breath out the lung “container” decreases which increases the pressure to 761mmHg pushing air out.
Identify the intrapulmonary pressure and the intrapleural pressure.
- Intrapulmonary pressure is the pressure inside the respiratory tract, at the alveoli.
- Intrapleural pressure is the pressure in the pleural cavity, between the parietal and visceral pleurae.
Identify the muscles and their actions involved in inhalation and exhalation
Identify and be able to calculate respiratory rates and volumes
Describe and understand Dalton’s Law and Henry’s Law and how they apply to respiration and gas exchange
- Dalton’s is of partial pressure. So if you add up all the pressures of the individual gases you will get the total pressure of the atmosphere of 760mmHg.
- Henry’s law has to do with the solubility of gases in a liquid enviorment under pressure by Boyles law. ^V=^P or vV=vP the solubility.
- Efficiency of diffusion at the blood air barrier because:
1. The differences in partial pressure across the blood air barrier are substantial
2. The distances involved in gas exchange are short.
3. the gases are lipid soluble. Both O2 and CO2 diffuse readily through the surfactant layer ant the alveolar and endothelial plasma membranes
4. The total surface area is large inside the lungs where gas exchange happens.
5. Blood flow and airflow are coordinated making it more efficient.
Describe the partial pressures of oxygen and carbon dioxide in alveolar air, blood of the pulmonary and systemic circuits, as well as in peripheral tissues.
- alveolar air - in it is normally a constant pressure of 100 for oxygen and 40 for carbon dioxide.
- blood of the pulmonary - where the blood coming in from the heart is 40 for oxygen and 45 for carbon dioxide. Since the concentration gradient is lower for oxygen and higher for carbon dioxide, the gradient moves from high to low. Leaving the pumonary capillary beds the oxygen is 100 and CO2 is 40, same as the alveolar air.
- systemic circuits - as the air travels to the systemic circuits the O2 goes to 95 due to the lung capillaries dumbing deoxynated blood into the pulmonary veins, while the CO2 is still 40.
- peripheral tissues - When it gets to the tissues the gradient in the tissues is 40 for O2 and 45 for CO2. O2 moving from high 95 in the arteriole end into the tissue of 40. and the CO2 moving from high 45 in the tissue to the 40 in the venule end, back to the heart O2 40 and CO2 45.
Understand the relationships between hemoglobin and pH, temperature, and BPG
- The increase of pH to alkaline creates a 100% saturation when picking up but reduces tremendously the ability to drop off at the tissues form 75% to now 85%. Where if it decreases to be acidic, it has a harder time picking up oxygen(about 86%), but is more likely to drop a higher probablility to drop off at the tissue (about 60%).
- The high the temperature the less effecient it is in picking up oxygen and it releases oxygen more readily at the tissues 85% to 55%. As the temperature gets colder the hemeglobin holds on to the oxygen tightly and doesn’t let go very readily at all.
- BPG is a byproduct of glycolysis. Because erythrocytes do not contain mitochondria, glycolysis is the sole method by which these cells produce ATP. BPG promotes the disassociation of oxygen from hemoglobin.
Describe how carbon dioxide is transported and modified in the blood.
- About 7% is soluble in the plasma.
- 97% is taken in by the red blood cell
- 23% is bound to the outside portions of the hem molecules.
- 70% is coverted to H2CO3 (carbonic acid) by carbonic anhydrase. This then dissociates into H+ and HCO2- (bicarbinate). The H+ is buffered and the HCO2- is removed to the plasma in exchange for Cl- (chloride shift).
- Carbonic acid bicarbonate buff equation
1. CO2 + H2O –> H2CO3–> H+ + HCO3-
Identify the function of the respiratory centers in the medulla oblongata
- Quiet Breathing
* Activity in the DRG (dorsal respiratory group) increases over a period of about 2 seconds, stimulating the inspiratory muscles. (inhalation)
* After the DRG become inactive. They remain quiet for 3 sec and allow the inspiratory muscles to relax. (passive exhalation takes place). - Forced breathing
* Increases in the level of activity in the DRG stimulate neurons of the VRG (ventral respiratory group) that activate the accessory muscles involved in inhalation.
* After inhalation, active exhalation takes place as the neurons of the expiratory center stimulate the appropriate accessory muscles.
Identify the function of the respiratory centers in the pons
- The apneustic stimulates the DRG.
- The pneumotaxic center inhibits the apneustic. So stimulating the pneumotaxic inhibits the apneustic which inhibits the DRG
*
Compare and contrast hypercapnia and hypocapnia, including the response of the respiratory system to these conditions.
