Lymphatic and Immune Systems

Lymphatic and Immune Systems I

• The lymphatic system maintains tissue fluid homeostasis and immune cell trafficking.
• Lymphatic vessels return leaked fluids from the blood vascular system back to the blood.
• Loss of lymphatic function leads to interstitial fluid accumulation, impaired immune cell trafficking, and decreased reverse cholesterol transport.
• Interstitial fluid becomes lymph once it enters the lymphatic capillaries.
• Interstitial fluid forms when blood plasma passes out of capillaries into tissues.
• Swelling is due to the failure of lymphatic capillaries to absorb interstitial fluid, which prevents its clearance.
• Blood capillaries maintain a tight, continuous barrier between blood and tissues due to zipper junctions and a continuous basement membrane.
• Lymphatic capillaries, unlike blood capillaries, use anchoring filaments to remain open and admit large particles from tissue fluid.
• Newly forming lymphatic capillaries have loose, overlapping endothelial cells, button-like junctions, and incomplete basement membranes, surrounded by anchoring filaments attached to the extracellular matrix, which are specialized for fluid and immune cell uptake from tissues.
• The pathway of lymph circulation starts from the lymphatic capillaries, to collecting lymphatic vessels, then to lymph nodes and lymphatic trunks and finally to lymphatic ducts
• Lymph ultimately drains into the blood circulation via subclavian veins through either the right lymphatic duct or the thoracic duct.
• The right lymphatic duct drains the right arm, right side of the head, and right side of the upper body.
• The thoracic duct empties lymph into the blood circulation at the left subclavian vein at the junction with the internal jugular vein.
• The lymphatic structure most likely impaired in a woman presenting with swelling in the left arm and chest following surgical removal of lymph nodes, with poor lymph drainage from the left side of her body, is the thoracic duct
• Valves arranged within lymphangion regions are the primary structural feature of collecting lymphatic vessels that prevent backflow of lymph.
• Direct pressure from arterial pulsations inside lymphatic capillaries does NOT contribute to the movement of lymph through collecting lymphatic vessels.
• Damaged lymphatic vessel valves that normally prevent backflow are directly responsible for backward movement of lymph in a patient with chronic lymphatic insufficiency.

Components of the Immune System

• The innate immune system responds rapidly and nonspecifically to any factor identified as non-self.
• Dendritic cells bridge innate and adaptive immunity via antigen presentation.
• Someone suffering has their innate immune response activated first, followed by activation of their adaptive immunity.
• Vasodilation during the acute inflammatory response increases blood flow to deliver more immune cells to the injury site.
• Swelling is most directly caused by increased vascular permeability.
• The swelling observed in a patient is most directly responsible for the histamine-induced increase in vascular permeability allowing plasma leakage.
• C3b protein in the complement system binds to pathogens and marks them for phagocytosis (opsonization).
• The ultimate goal of Membrane Attack Complex (MAC) formation in the complement cascade is to cause massive water influx and lysis of the target microbe.
• Cleavage of C3 into C3a and C3b is an event shared by the classical, alternative, and lectin pathways of complement activation
• Cleavage of C3 into C3a and C3b is what directly triggers the formation of the Membrane Attack Complex (MAC) in the complement cascade
• Deficiency in C3 prevents opsonization and MAC formation, weakening innate immunity.
• Diapedesis is the process by which leukocytes squeeze through capillary walls into surrounding tissues.
• Chemotaxis guides immune cells toward the site of infection along a chemical gradient.
• Neutrophils are actively migrating through the walls of blood capillaries into the surrounding tissues due to chemotaxis.
• Diapedesis occurs first to allow immune cells to exit the blood, and is followed by chemotaxis to guide them to the exact location of injury.
• Opsonization is the coating of a pathogen by antibodies or complement proteins to enhance phagocytosis.
• During phagocytosis, a phagolysosome forms inside the phagocyte to digest the pathogen.
• The absence of opsonins prevents recognition and efficient phagocytosis of pathogens by neutrophils.
• Interferons signal neighboring cells to enter a virus-resistant state.
• Epithelial cells can produce type I interferons (alpha and beta) in response to viral infections.
• Interferons convert neighboring cells into a virus-resistant state by promoting antiviral protein production.
• Pathogen-associated molecular patterns (PAMPs) are conserved microbial structures recognized as foreign by the innate immune system.
• Pattern recognition receptors (PRRs) recognize PAMPs and trigger immune responses.
• Failure to recognize PAMPs due to the absence of specific antibodie is the failure in the patient's innate immune defense
• Exogenous pyrogens → endogenous pyrogens → prostaglandin E2 production → increased hypothalamic setpoint is the sequence that leads to fever following an infection
• Prostaglandin E2 (PGE2) signals the hypothalamus to increase the body's temperature setpoint.
• Fever reduces oxygen levels in cells by causing vasoconstriction and shivering that increases metabolic rate.
• Cytokines stimulate the anterior hypothalamus to release prostaglandin, raising the body’s temperature setpoint.
• Mast cells increase blood flow and vascular permeability by releasing histamine.

Lymphatic and Immune Systems II

• B cells secrete antibodies after differentiating into plasma cells
• Helper T cells activate other immune cells through cytokine release, while Cytotoxic T cells destroy infected body cells
• Plasma cells secrete antibodies for humoral immunity,and Helper T-cells secrete cytokines to enhance B-cell and macrophage activity
• Complete antigens are large molecules capable of directly triggering an immune response by itself
• A hapten is a small molecule that elicits an immune response only when attached to a larger carrier molecule
• The drug molecule acts as a hapten, becoming immunogenic only when attached to a carrier protein, immunological basis of allergic reaction
• An antigenic determinant (also called an epitope) is a specific region on an antigen recognized by immune cells
• MHC class I molecules are found on almost all nucleated cells and present endogenous (self or viral) peptides to cytotoxic T-cells
• Professional antigen-presenting cells (APCs) internalize antigens and present them on MHC class II molecules for recognition by helper T-cells
• MHC molecules display peptide fragments on the cell surface for recognition by T-cell receptors (TCRs)
• CD8+ T cells recognize peptides presented by MHC class I molecules
• endogenous antigens derived from the cell's own proteins or intracellular pathogens describe the type of antigen presented by MHC class I molecules
• A CD8+ T-cell directly kills the infected cell by triggering apoptosis after recognizing an antigen presented by an MHC class I molecule
• Infected cells present viral peptides on MHC class I molecules, which are recognized by CD8+ cytotoxic T-cells because cells begins displaying viral peptides on their surface bound to MHC class I molecule.
• Primary lymphoid where lymphocytes develop and mature is the bone marrow
• Spleen is the secondary lymphoid organ where lymphocytes encounter antigens and are activated
• A primary lymphoid organ is defective because lymphocyte development and maturation are impaired during Immunodeficiency disorder
• Microfold (M) cells in Peyer's patches transport antigens from the gut lumen into the underlying immune tissues
• A secondary follicle is a region where B-cells undergo proliferation after encountering antigen within a Peyer's patch
• The spleen filters blood, removing old, damaged, or infected blood cells, that describes function of the spleen in the immune system
• A kidney-shaped structure containing the cortex, paracortex, and medulla for immune cell organization best describes structure of lymph node
• The spleen filters blood directly, removing old, damaged blood cells and blood-borne pathogens which explains why the spleen is important in immune protection against blood- born pathogens.
• Both, B-cells and T-cells originate in the red bone marrow
• Immunocompetence and self-tolerance describes two key properties that developing B-cells and T-cells must acquire during lymphocyte maturation
• Positive selection of T-cells occur during maturation in the cortex of the thymus
• During negative selection of T-cells, Binding too tightly to self-antigens results to T-cell apoptosis
• Naïve lymphocytes describes lymphocytes that have developed immunocompetence but have not yet encountered their specific antigen
• It undergoes clonal selection and proliferates into effector and memory cells which results to a lymphocyte after its antigen receptor successfully binds to an antigen.
• Memory lymphocytes formed after vaccination recognized the virus and initiated a rapid immune response protects from immunological mechanism which occurred after vaccinated and exposed to the virus in his school
• In the T cell-dependent pathway of B cell activation, CD4+ T helper cell releases cytokines that help fully activate the B cell
• B cells are activated by repetitive antigens that crosslink B cell receptors (BCRs) which describes the T cell-independent pathway of B cell activation
• T cell-independent pathway is the pathway most likely led to a patient experiencing a mild infection caused by a bacterium that has a highly repetitive surface structure with IgM-dominated antibody response
• Variable region of the heavy and light chains is responsible for recognizing and binding to a specific antigen
• The class and effector function of the antibody is determined by constant region of an antibody
• Heavy chain variable region is the region responsible for the ability of some antibodies (but not others) to bind to the viral antigen.
• IgM antibody is the first produced during an initial immune response
• IgG is the most abundant in the blood and provides long-term immunity
• IgG and IgM are primarily involved in the infant's immunity at birth and in the early stages of the infection
• Neutralization involves antibodies blocking the harmful parts of viruses or bacterial toxins so they cannot bind to tissue cells
• Phagocytosis is enhanced by the antibody-mediated agglutination and precipitation of antigens
• Neutralization and agglutination are mechanisms of antibody action primarily responsible for immune response as antibodies that bind to viral particles, preventing them from binding and entering host cells
• It takes a few days to activate B cells and produce antibodies primary immune response
• generated during the primary immune response secrete antibodies.
• It is faster, stronger, and longer-lasting characteristic feature of the secondary immune response compared to the primary immune response
• Rapidly differentiate into plasma cells and secrete antibodies in the secondary immune response
• Memory B cells quickly recognized the virus and generated a strong, rapid antibody response more rapid and effective immune response during the second exposure
• IgM the antibody class appears first but in moderate amounts during the primary immune response
• Immediate activation and higher levels of IgG: in the secondary immune response compared to the primary response
• that are primarily responsible for the sustained high antibody levels observed after the booster which is due to the activation of memory B cells:

Active and Passive Immunity

• Pre-formed antibodies are transferred from an external source, offering temporary protection, that describes passive immunity
• Maternal transfer of IgG antibodies to a fetus via placenta that is naturally acquired
• In patient with having IgG antibodies Newborn is found to have IgG antibodies against a virus shortly after birth due to passive immunity due to mother immunity and no memory cells formed

Respiratory System I

• Gas exchange between the environment and the lungs is external respiration
• Carbon dioxide (CO2) moves from the blood into the tissues as the gas moves during internal respiration
• External respiration is impaired (Pneumonia patient)
• It provides oxygen necessary for for ATP production
• Synthesizing glucose major function of the respiratory
• The function of the respiratory system that is most directly impaired in a 55-year-old man coming into the emergency room with shortness of breath and confusion is.
• Trachea is part of the lower respiratory tract.
• the conducting zone of the respiratory system functions with filtering, warming, and moistening incoming air.
• The respiratory system is primarily responsible for trapping these particles which acts as main filtering air.
• Nose/ Nasal Cavity,Pharynx,Larynx is correct order of anatomical structures.
• To filter large particles from inhaled air, is the primary function of the nasal hairs at the entrance of the nose.
• Nasal cavity and the nest structures (PHarynx) will likely trap the large dust particle inhaled by the patient
• They reduce the weight of the skull and act as resonant chambers for voice are the function of the paranasal sinuses.
• Increase surface area to warm and humidify incoming air is the role of the nasal conchae (turbinates) in respiration.
• Fluid accumulation in the sinuses disrupts the skull's resonance, affecting the voice, why the patient is experiencing the facial pressure during sinuses imaging.
• Exchanging oxygen and carbon dioxide with the blood the air conditioning incoming into the nasal functions is not the moisturizing
• the inspired air filtration that warm incoming in blood flow by increasing water
• The patient is more prone to the throat irritation and the infection due to not having mucosals prevents humidifying the proper filtration and increasing heating that inspires the air
• They slow airflow and create turbulence, helping trap particles in mucus describes the function of the nasal meatuses?
• Beneath each nasal concha in the lateral nasal cavity, is where the nasal meatuses located?
• In slowing down the airflow is the structure most likely functioning abnormally and what is its typical role in which nasal congestion builds through frequent congestion and heavy breathing.
• Epiglottis structure prevents food from entering the respiratory tract.
• Cartilage and skeletal muscle best describes primary components of the larynx
• Dysfunction of the epiglottis is allowing food to enter the airway, and inflammation of the vocal cords is impairing voice production the

How Glottis enables sound production

• True vocal cords structures are primarily responsible for producing sound during exhalation
• Vibration of interruption of air flow mainly determines the pitch
• The vibration that prevents proper vibration decreasing the sound from proper exhaling
• Rings of hyaline makes trachea prevented from collapsing

Hierarchical branching

• The airway walls decreases the cartilage and smooth muscle has decreased
• the terminal bronchii correct sequence from the trache that is from primary bronchii secondary bronchii and terminal bronchii
• The hierarchy structure that is most likely obstruct is where bronchiii is branching into three
• Primary site for gas exchange from the lungs is Alveoli
• Respiratory bronchioles is the way towards the pathway
• The is most likely damaged is having decrease surface gas and exhaling with high gas exhaling into blood

Respiratory Function

• The membrane is a barrier for gas exchange
• Surfactant is not normally happening is underdeveloped and decreases the surface tension in

Respiratory membrane of pneumocytes functions

• Structure has exchange for barrier
• Type II surfactant, to reduce the tension function
• What will be if the membrane is impaired and the lungs have oxygen: diffusion of oxygen, and having higher elasticity prevents upper membrane due to thin layer

Airway

• They trap/ move debris cilia that has epithelium
• Thin layer that supports immune

Breathing

• True
• Lungs collapse due to visceral