Stanbridge - T1 - Physiology - W8 - Digestive, Endocrine, Lymphatic, and Immune Systems
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Questions and Answers

What is the primary site of T cell development and immunocompetence?

  • Spleen
  • Liver
  • Thymus gland (correct)
  • Bone marrow

    • Which type of immunity is primarily mediated by B cells and involves the secretion of antibodies?

  • Innate immunity
  • Humoral immunity (correct)
  • Passive immunity
  • Cellular immunity

    • What happens to B cells once they meet their antigen and become activated?

  • They become cytotoxic T cells.
  • They transform into plasma cells or memory cells. (correct)
  • They migrate to the liver.
  • They undergo apoptosis.

    • What is a characteristic feature of active immunity?

    <p>It is developed after exposure to antigens.</p> Signup and view all the answers

    What type of cells are responsible for secreting antibodies during the humoral immune response?

    <p>Plasma cells</p> Signup and view all the answers

    Which process allows a B cell to differentiate into a cell that can more effectively respond to a specific antigen?

    <p>Clonal selection</p> Signup and view all the answers

    What is a defining characteristic of passive immunity?

    <p>It is immediate but temporary.</p> Signup and view all the answers

    How do antibodies function in the immune response?

    <p>By marking antigens for destruction</p> Signup and view all the answers

    What is the primary function of natural killer cells in innate immunity?

    <p>To directly induce apoptosis in target cells</p> Signup and view all the answers

    Which of the following is NOT a characteristic of innate immunity?

    <p>It requires specific information to target pathogens</p> Signup and view all the answers

    What role do defensins play in innate immunity?

    <p>They have antimicrobial properties affecting pathogens</p> Signup and view all the answers

    Which factor increases the effectiveness of phagocytosis?

    <p>Opsonization of pathogens by opsonins</p> Signup and view all the answers

    What distinguishes active immunity from passive immunity?

    <p>Active immunity is generated by the immune system, while passive immunity is transferred</p> Signup and view all the answers

    What is the primary function of cytotoxic T cells in the immune response?

    <p>To attack and kill infected cells</p> Signup and view all the answers

    How do regulatory T cells contribute to the immune system?

    <p>By dampening the immune response</p> Signup and view all the answers

    What condition is characterized by the immune system mistakenly attacking its own tissues?

    <p>Autoimmunity</p> Signup and view all the answers

    Which of the following is an example of an autoimmune disease?

    <p>Graves Disease</p> Signup and view all the answers

    What is the main consequence of having a condition like AIDS?

    <p>Impaired function of helper T cells</p> Signup and view all the answers

    Which mechanism do cytotoxic T cells use to induce cell death?

    <p>Secretion of perforins and granzymes</p> Signup and view all the answers

    What role do autoantibodies play in autoimmune diseases?

    <p>They attack self-tissues.</p> Signup and view all the answers

    What is the primary cause of immunodeficiency in diseases like Hodgkin’s lymphoma?

    <p>Cancer of B cells leading to depressed lymph node activity</p> Signup and view all the answers

    What does cellular immunity primarily involve?

    <p>Engagement of cytotoxic T cells and helper T cells</p> Signup and view all the answers

    What is the function of antibodies in the humoral immune response?

    <p>To tag pathogens for destruction</p> Signup and view all the answers

    Which of the following statements correctly describes the function of B-Lymphocytes?

    <p>B-Lymphocytes make antibodies.</p> Signup and view all the answers

    What role do T-Lymphocytes play in the immune response?

    <p>They recognize and destroy cells infected by viruses.</p> Signup and view all the answers

    What is the primary difference between active and passive immunity?

    <p>Active immunity requires exposure to a pathogen; passive immunity does not.</p> Signup and view all the answers

    How do natural killer cells contribute to the immune defense?

    <p>They target and kill virus-infected cells and tumor cells.</p> Signup and view all the answers

    Which line of defense in immunity is referred to as adaptive immunity?

    <p>Third line of defense.</p> Signup and view all the answers

    What mechanism is primarily involved in humoral immunity?

    <p>Production of antibodies by B cells.</p> Signup and view all the answers

    What is a characteristic feature of innate defenses?

    <p>They provide a nonspecific response to any invading pathogen.</p> Signup and view all the answers

    Which type of lymphocyte is involved in both cell-mediated and humoral immunity?

    <p>T-Lymphocytes.</p> Signup and view all the answers

    Which cytokine is primarily responsible for activating T-Lymphocytes?

    <p>IL-2.</p> Signup and view all the answers

    What are the targets of humoral immunity primarily composed of?

    <p>Bacteria and toxins.</p> Signup and view all the answers

    What type of T cells are primarily responsible for directly attacking and destroying cells containing foreign material?

    <p>Cytoxic T cells</p> Signup and view all the answers

    Which of the following is a role of Helper T cells in the immune response?

    <p>Activate B cells and other T cells</p> Signup and view all the answers

    Memory CD4 cells are primarily derived from which type of cells?

    <p>Helper T cells</p> Signup and view all the answers

    What is the primary function of Regulatory T cells in the immune system?

    <p>Moderate immune responses</p> Signup and view all the answers

    Which component is essential for CD8 T cells to perform their function effectively?

    <p>Helper T cells</p> Signup and view all the answers

    What distinguishes humoral immunity from cellular immunity?

    <p>Primarily uses antibodies</p> Signup and view all the answers

    Which type of immunity involves the transfer of pre-formed antibodies from one individual to another?

    <p>Passive immunity</p> Signup and view all the answers

    When activated, what do Helper T cells become?

    <p>Memory CD4 cells and Helper T cells</p> Signup and view all the answers

    Which cells are primarily involved in activating B cells to produce antibodies?

    <p>Helper T cells</p> Signup and view all the answers

    In the context of cellular immunity, what happens if Helper T cells are absent?

    <p>No effective adaptive immune response occurs</p> Signup and view all the answers

    Study Notes

    Digestive System

    • This system is responsible for the breakdown of food into absorbable nutrients and the removal of solid waste products
    • It's divided into two major components: the digestive tract and the accessory organs.

    Objectives

    • Students should be able to describe the pathway of a bolus through the gastrointestinal tract (GI tract) /alimentary canal.
    • They should understand the digestive processes occurring in each area of the GI tract.
    • They should know the names and functions of the accessory organs to the GI tract.
    • Students will learn the neural control of the GI tract.

    Metabolism & Cellular Metabolism

    • Metabolism: refers to all chemical reactions in an organism.
    • Cellular Metabolism: includes all the chemical reactions within cells, like glycolysis, the Krebs cycle, and oxidative phosphorylation. It also provides energy to maintain homeostasis and perform essential functions.

    Main Functions of the Digestive System

    • Transportation through the GI tract.
    • Digestion: mechanical (chewing, churning) and chemical (enzymes & digestive juices).
    • Absorption.
    • Elimination.

    Major Divisions of Digestive System

    • Digestive Tract (GI Tract): The tube-like structure beginning at the mouth and ending at the anus. This is where food is broken down and digested.
    • Accessory Organs: Organs that assist in digestion but are not part of the tract itself, like the liver, pancreas, gallbladder, and salivary glands. They produce or store substances critical for food breakdown.

    Organs of the Digestive System

    • Mouth (oral cavity).
    • Pharynx.
    • Esophagus.
    • Stomach.
    • Small intestine (duodenum, jejunum, ileum).
    • Large intestine (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal).
    • Appendix.

    Overall Gastrointestinal Tract Activities

    • Ingestion: taking food into the body.
    • Mechanical Breakdown: chewing, churning, and segmentation.
    • Propulsion: swallowing, peristalsis.
    • Digestion: the process of breaking down food chemically and mechanically.
    • Absorption: taking nutrients from digested food into the bloodstream.
    • Defecation: elimination of solid waste products.

    Digestion

    • Mechanical Digestion: the physical breakdown of food, such as chewing and churning in the stomach.
    • Chemical Digestion: the breakdown of food by chemical means such as through enzymes, acids, and water.

    The Mouth (Oral Cavity)

    • Ingestion – receiving food.
    • Mechanical Breakdown: Mastication (chewing), mixing by the tongue.
    • Digestion:Salivary amylase begins breaking down sugars.
    • Propulsion: moves food into the pharynx.

    The Pharynx

    • A muscular passageway that connects the oral cavity to the esophagus.
    • It's important for swallowing (deglutition)
    • It prevents food from entering the nose
    • The epiglottis covers the trachea when swallowing to prevent food from getting into the lungs

    The Esophagus

    • A muscular tube that transports food from the pharynx to the stomach.
    • It lubricates food with mucus.
    • It moves food by peristalsis.
    • It's anterior to the trachea.

    Swallowing (Deglutition)

    • Buccal phase: voluntarily moving food to the pharynx
    • Pharyngeal-esophageal phase: involuntary moving food down to the esophagus and into the stomach.
    • Uvula and soft palate raise to prevent food from going up into the nose.
    • Epiglottis covers the trachea, preventing food from entering the lungs.

    The Stomach

    • Fundus: the top part
    • Cardiac sphincter: separates the stomach from the esophagus.
    • Pylorus: the last part of the stomach
    • Pyloric sphincter: separates the stomach from the small intestine.

    Stomach Functions

    • Stores food and liquid, and propels them with peristalsis.
    • Secretes gastric juice (including mucus and hydrochloric acid).
    • Mechanical churning
    • Chemical digestion (by hydrochloric acid and pepsin, which breaks down proteins and destroys foreign organisms).

    The Small Intestines

    • Duodenum: The first part, responsible for much of the chemical digestion.
    • Jejunum: The middle part, the primary site of nutrient absorption.
    • Ileum: The last part, responsible for reabsorbing bile salts.

    Small Intestines Functions

    • Secretes mucus (to neutralize acid chyme).
    • Secretes enzymes to break down food.
    • Absorbs digested food (carbohydrates, proteins, fats, nucleic acids, vitamins, electrolytes, and water).
    • Villi and microvilli increase the absorptive surface area.
    • Lacteals absorb fats.

    Segmentation

    • Nonadjacent segments of the alimentary canal organs contract and relax causing food to be moved forward and backward, mixing food and breaking it down mechanically.

    Absorption of Fats

    • Lacteals absorb fats,
    • Fat/lymph mixture -chyle- drains into the cisterna chyle,
    • Chyle merges into lymphatic circulation, enters blood in veins near the heart,
    • Liver processes absorbed fats.

    The Large Intestines

    • Cecum: a pouch-like structure where the small intestine connects to the large intestine
    • Ileocecal valve: a one-way valve that controls the flow of materials from the small intestine into the large intestine
    • Vermiform appendix: a small, finger-like structure that hangs from the cecum.
    • Colon (four parts): ascending, transverse, descending, sigmoid.
    • Rectum: a temporary storage area for feces
    • Anal canal: the last portion of the large intestine, connecting the rectum to the anus
    • Anus: ends the digestive tract, with the anal sphincter controlling defecation.

    Large Intestine Functions

    • Absorbs water and electrolytes from digested food.
    • Secretes mucus, easing the passage of feces.
    • Bacteria digest remaining food and produce some vitamins (e.g., vitamin K., B complex vitamins).
    • Propels feces to the rectum through mass movements.
    • Stores and concentrates feces.
    • Defecation triggered by a reflex from rectal distension.

    Appendix

    • Attached to the posteromedial surface of the cecum
    • Contains lymphatic tissue, plays a role in the immune response.
    • Stores bacteria, which can be returned to the GI tract as needed.

    Accessory Organs

    1. Salivary glands: contains enzymes that digest carbohydrates.
    2. Liver: produces bile, which breaks down fats in the small intestine.
    3. Gallbladder: stores bile.
    4. Pancreas: secretes digestive enzymes into the duodenum.

    Liver, Pancreas, Gall Bladder

    • Diagram showing the locations and relationships of the liver, pancreas, and gallbladder.
    • They play critical roles in the production and storage of vital digestive substances.

    Liver Functions

    • Makes bile to break down fats in the small intestine.
    • Stores glucose as glycogen, converting it back to glucose when needed.
    • Modifies fats into usable form (cholesterol).
    • Stores vitamins and iron.
    • Makes proteins for blood plasma (albumin, globulins, clotting factors).
    • Detoxifies the blood (e.g., alcohol).
    • Recycles bilirubin (a byproduct of red blood cell breakdown).

    Activation of Pancreatic Proteases in the Small Intestines

    • Diagram showing the activation of inactive pancreatic enzymes (trypsinogen, chymotrypsinogen, procarboxypeptidase) in the small intestine
    • The activation process is crucial for optimal digestion in the duodenum.

    Bile and Pancreatic Juice Secretion and Release

    • Diagram explaining the hormonal mechanisms that regulate the secretion of bile and pancreatic juice.
    • How hormones such as CCK and secretin trigger these secretions.

    The Enterohepatic Circulation

    • Diagram showing the recycling of bile salts between the small intestine and liver.
    • The liver reabsorbs the majority of secreted bile salts, reducing the loss of potentially important molecules.

    Overall Digestion and Absorption of Biological Macromolecules

    • Summaries of how carbohydrates, proteins, lipids, and nucleic acids are broken down in the GI tract.
    • The organs involved in the breakdown and absorption of these molecules.
    • Absorption sites and subsequent transport pathways.

    Control of Digestion: Hormonal

    • Digestive system hormones (gastrin, gastric inhibitory peptide, secretin, cholecystokinin) and their functions in regulating different aspects of digestion.

    Nervous System Control of the GI Tract: Enteric Nervous System

    • The enteric nervous system is the local nervous system, controlling the motility of the GI tract
    • It is the intrinsic plexuses (submucosal and myenteric) located in the walls of the alimentary canal.

    Central Nervous System Control of the GI Tract

    • The CNS regulates the GI tract through various reflexes.
    • These reflexes can be initiated by internal and external stimuli.

    Control of Digestion: Nervous System Control

    • Description of how the parasympathetic and sympathetic nervous systems influence digestive activity
    • Relationship between stress and digestive function.

    Pancreas & Associated Hormones

    • The pancreas, having exocrine as well as endocrine functions.
    • The roles of α- (alpha) and β- (beta) cells in producing hormones like glucagon and insulin..

    Pancreas & Diabetes

    • Diabetes Mellitus is a condition related to the lack of insulin.
    • Type 1 Diabetes: The pancreas fails to produce insulin.
    • Type 2 Diabetes: The body's cells do not respond properly to insulin.

    Negative Feedback Loop of the Pancreas and Blood Sugar

    • Diagram explaining the negative feedback loop by means of insulin.
    • How blood sugar is regulated through the action of hormones.

    Overview of B and T Lymphocytes

    • Table summarizing the essential differences between B and T cells (their origins, sites of maturation, primary targets, function types, immune responses, memory cell formation).

    Autoimmune Diseases

    • Immune system produces autoantibodies and cytotoxic T cells, and attacking the body's own tissues
    • Diseases like Rheumatoid arthritis, Myasthenia Gravis, Multiple Sclerosis, Graves Disease and SLE (Systemic lupus erythematosus), and Glomerulonephritis.

    Immunodeficiency

    • Congenital or acquired disorders, impaired production or impaired function of immune cells (e.g., lymphocytes).
    • Examples such as AIDS caused by HIV, Hodgkin's lymphoma.

    Lymphatic System

    • Components such as lymphatic vessels, lymphatic organs (lymph nodes, spleen, and thymus), and the functions of these components (fluid balance, immunity).
    • Pathway of lymph through the body.

    Lymphoid Organs

    • Spleen: a filter for blood, recycling components.
    • Thymus: maturing site for T cells.
    • Lymph nodes: filter lymph.
    • Mucosa-associated lymphoid tissue (MALT): tissues in mucosal areas
    • Peyer's patches: collections of lymphatic tissue in the small intestine.

    Tonsils

    • Overview and location of various types of tonsils (palatine, lingual, pharyngeal or adenoids, and tubal tonsils).

    White Blood Cells (WBCs)

    • Two categories of WBCs: granular (neutrophils, eosinophils, basophils) and agranulocytes (monocytes, lymphocytes).
    • Functions of these cells.

    Granulocytes

    • Specific roles of neutrophils, eosinophils, and basophils in fighting different kinds of pathogens.

    Agranulocytes

    • Monocytes' main functions, including phagocytosis and antigen presentation.
    • Three main kinds of lymphocytes: B cells, T cells, and Natural Killer cells. The functions of each.

    First and Second Lines of Defense

    • The body's responses to pathogens, including surface barriers (skin and mucous membranes) and innate internal defenses (phagocytes, inflammation, fever, and antimicrobial proteins).

    Immune System

    • Overview of innate vs. adaptive immunity.
    • Summary of each type.

    Immune System: Innate and Adaptive Defenses

    • Summary of the various components and their functions associated with the different levels of innate and adaptive immune responses.

    Antibodies

    • Antibodies (as part of the humoral immune response) in the process of fighting pathogens (bacteria, viruses, etc.).
    • The various methods via which antibodies work (neutralization, agglutination, opsonization, activation of complement).

    Cellular Immunity

    • T cell activation and differentiation (helper T cells, cytotoxic T cells, and regulatory T cells).
    • How these cell types react to fight pathogens.
    • Helper T-cells function in activating B-cells and other T-cells.
    • Cytotoxic T-cells directly destroy infected host cells.
    • Regulatory T-cells help to moderate the immune response.

    Overview of B and T Lymphocytes

    • Summarization of B and T lymphocyte functions, origins, maturation sites, and cellular outcomes.

    Autoimmune Diseases

    • Explanation of how the immune system incorrectly identifies and attacks the body's own tissues.
    • Listing of some autoimmune examples, such as rheumatoid arthritis, myasthenia gravis, multiple sclerosis, Graves disease, SLE (systemic lupus erythematosus), and glomerulonephritis.

    Immunodeficiency

    • Disorders that impair immune function (congenital and acquired)
    • Examples of immunodeficiencies, including AIDS and lymphoma.

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    Test your knowledge on key concepts in immunology, including T cell development, B cell function, antibody secretion, and the differences between active and passive immunity. This quiz covers essential features of both innate and adaptive immune responses, and the role of various immune cells.

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