BIOS 255 Week 8 Final Exam (Essay & Explanatory)

Student Name

Chamberlain University

BIOS-255: Anatomy & Physiology III with Lab

Prof. Name

Date

Innate and Adaptive Immune Systems

Question: Describe innate and adaptive immune systems, how they work, and how they interact.

The immune system is composed of two fundamental branches: the innate immune system and the adaptive immune system. The innate immune system serves as the body’s initial line of defense, providing a rapid but non-specific response to pathogens. This system includes physical barriers like skin and mucous membranes, chemical defenses such as antimicrobial proteins and enzymes, and cellular components like neutrophils, macrophages, and natural killer cells. These elements function to recognize and eliminate pathogens through pattern recognition receptors (PRRs) that detect pathogen-associated molecular patterns (PAMPs).

In contrast, the adaptive immune system provides a targeted and highly specific defense. It involves lymphocytes—T cells and B cells—that recognize specific antigens. Upon first exposure to a pathogen, the adaptive response is slower but generates immunological memory, which ensures a faster and more efficient response during future exposures. The interaction between the two systems is critical; for instance, dendritic cells, part of the innate system, present antigens to T cells to initiate the adaptive response. Thus, the innate system not only provides initial protection but also activates and shapes the adaptive response.

Antibody Subclasses

Question: Explain the various subclasses of antibodies – how they are similar, how they differ.

Antibodies, or immunoglobulins (Ig), are glycoproteins produced by B cells that play a vital role in immune defense. All antibodies share a similar Y-shaped structure composed of two heavy and two light chains, but they are classified into five main subclasses based on their heavy chain: IgG, IgA, IgM, IgE, and IgD.

Antibody Class	Location/Function	Unique Features
IgG	Circulating in blood and tissues	Most abundant, provides long-term immunity
IgA	Mucosal surfaces (saliva, tears, intestines)	Protects mucosal areas, forms dimers
IgM	Blood and lymph	First antibody produced in response to infection
IgE	Skin, lungs, mucous membranes	Triggers allergic responses, protects against parasites
IgD	B cell surface	Role not fully understood, involved in B cell activation

Respiratory Definitions

Question: Define ventilation, external respiration, and internal respiration. Be sure to identify their functions and where they occur.

Ventilation refers to the mechanical process of moving air into and out of the lungs, primarily through the contraction and relaxation of the diaphragm and intercostal muscles. External respiration involves the exchange of gases between the alveoli in the lungs and the surrounding capillaries; oxygen diffuses into the blood while carbon dioxide diffuses out. Internal respiration, in contrast, occurs in peripheral tissues where oxygen is delivered from the blood to the cells and carbon dioxide is collected for removal.

Neural Control of Ventilation

Question: Explain the neural control of ventilation, including brain centers, sensory and motor signals.

Ventilation is regulated by neural centers located in the brainstem, particularly the medulla oblongata and pons. The medullary rhythmicity area controls the basic rhythm of breathing, while the pontine centers fine-tune the rate and pattern. Chemoreceptors in the carotid and aortic bodies detect changes in blood levels of CO2, O2, and pH. These sensory signals are relayed to the brainstem, which then sends motor commands via the phrenic and intercostal nerves to the diaphragm and intercostal muscles, enabling breathing movements.

Gas Transport in Blood

Question: Describe how oxygen and carbon dioxide are transported in the blood, emphasizing factors affecting loading/unloading in the lungs vs. tissues.

Oxygen is predominantly transported by hemoglobin within red blood cells. In the lungs, where oxygen partial pressure is high, hemoglobin binds oxygen. In tissues with lower oxygen levels and higher carbon dioxide levels, oxygen is released. Carbon dioxide is transported mainly as bicarbonate ions, but also bound to hemoglobin and dissolved in plasma. The Bohr effect, temperature, and pH all influence the efficiency of oxygen and carbon dioxide transport.

T Cell Subclasses

Question: List and briefly describe the major functions of the various subclasses of T cells.

BIOS 255 Week 8 Final Exam (Essay & Explanatory)

T cells are differentiated into several functional types:

T Cell Type	Function
Helper T (CD4+)	Activate B cells, cytotoxic T cells, and macrophages
Cytotoxic T (CD8+)	Destroy virus-infected and tumor cells
Regulatory T	Suppress excessive immune responses to maintain tolerance

Adaptive Immune Response

Question: Explain the similarities and differences between primary and secondary responses of the adaptive immune response.

The primary immune response occurs upon the first exposure to an antigen. It is slower and less robust, requiring time for antigen recognition and lymphocyte activation. In contrast, the secondary response is faster and more intense, thanks to memory B and T cells generated during the initial exposure. These memory cells facilitate a rapid and specific response to previously encountered pathogens.

Function of the Spleen

Question: Functions of the Spleen

The spleen filters blood, removes aged or damaged red blood cells, and initiates immune responses against blood-borne antigens. It also acts as a reservoir for white blood cells and platelets.

Muscles in Respiration

Question: All muscles used in exhaling and inhaling

Inhalation involves the diaphragm and external intercostals, which expand the thoracic cavity. Exhalation is typically passive but becomes active during forceful breathing, engaging the internal intercostals and abdominal muscles.

Characteristics of the Thymus

Question: Know the characteristics of the thymus

The thymus is a bilobed gland located in the mediastinum. It is essential for the maturation and differentiation of T lymphocytes and is most active during childhood, shrinking with age.

Components of the Lymphatic System

Question: Know the components of the lymphatic system

The lymphatic system comprises lymph, lymphatic vessels, lymph nodes, the spleen, thymus, and tonsils. These structures support immune surveillance, fluid balance, and fat absorption.

Respiratory Conduction System

Question: Know the conduction system for air

Air travels through the nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli. The conducting zone ends at the terminal bronchioles, and the respiratory zone begins at the respiratory bronchioles, leading to alveolar ducts and alveoli where gas exchange takes place.

Site of Gas Exchange in Lungs

Question: Where gas exchange occurs in the lung and how this occurs

Gas exchange occurs in the alveoli. Oxygen diffuses across the alveolar membrane into capillaries, while carbon dioxide diffuses from the blood into the alveoli for exhalation. This process relies on partial pressure gradients.

Functions of Key Blood and Immune Cells

Question: Function of RBCs, T-cells, B-cells, Cytotoxic T cells, Natural killer cells

Red blood cells (RBCs) are specialized for oxygen transport, using hemoglobin to carry oxygen from the lungs to tissues and return carbon dioxide for exhalation. T cells play a central role in the adaptive immune response, with various subsets performing distinct functions. B cells are responsible for producing antibodies that neutralize pathogens. Cytotoxic T cells (CD8+) eliminate infected or cancerous cells, while natural killer (NK) cells, part of the innate immune system, target virus-infected and tumor cells without prior sensitization.

Return of Lymph to Circulation

Question: Return of lymph to venous circulation

Lymph is collected from interstitial fluid in tissues and transported through lymphatic capillaries into larger vessels and nodes. Eventually, it is returned to the bloodstream via the thoracic duct or right lymphatic duct, which drain into the subclavian veins, maintaining fluid balance in the body.

Mechanics of Breathing

Question: Know the process of inhalation and exhalation (the steps involved)

Inhalation begins with the contraction of the diaphragm and external intercostal muscles, expanding the thoracic cavity and decreasing internal pressure. This negative pressure draws air into the lungs. Exhalation is generally passive, occurring when these muscles relax, increasing pressure and expelling air. During forceful exhalation, the internal intercostals and abdominal muscles actively compress the thoracic cavity.

Erythropoiesis Regulation

Question: Describe the feedback mechanism involved in erythropoiesis.

Erythropoiesis is regulated by a negative feedback loop involving erythropoietin (EPO), a hormone produced by the kidneys in response to hypoxia (low oxygen levels). When oxygen delivery to tissues decreases, EPO levels rise, stimulating the bone marrow to increase red blood cell production. As oxygen levels normalize, EPO production diminishes.

The Cardiac Cycle

Question: Describe the cardiac cycle (include conduction, contraction, heart sounds, and EKG information).

The cardiac cycle comprises systole (contraction) and diastole (relaxation). It begins with electrical impulses from the sinoatrial (SA) node, spreading through the atria and to the atrioventricular (AV) node, down the bundle of His, and into the Purkinje fibers. This electrical activity is recorded as the electrocardiogram (EKG). Heart sounds are caused by the closing of valves: the “lub” (S1) during AV valve closure and the “dub” (S2) during semilunar valve closure.

Blood Pressure Regulation

Question: Describe the factors that increase blood pressure (negative feedback involved in blood pressure regulation).

Blood pressure can be increased by factors such as elevated cardiac output, vasoconstriction, and increased blood volume. Baroreceptors in the aortic arch and carotid sinus detect high blood pressure and trigger parasympathetic responses to lower heart rate and dilate vessels. Conversely, low pressure stimulates sympathetic activity to increase cardiac output and vascular resistance.

Non-Specific Immune Responses

Question: Describe the responses involved in non-specific immunity.

Non-specific or innate immunity includes defenses like skin, mucous membranes, inflammation, fever, and phagocytic cells. These mechanisms respond quickly to a wide range of pathogens. For example, macrophages and neutrophils engulf invaders, and inflammation isolates infection and recruits immune cells.

Cell-Mediated Immunity

Question: Describe cell-mediated immunity (antigen presentation, antigen recognition, activation, and cellular response). Include both CD8 and CD4 T cells.

Cell-mediated immunity involves T cells recognizing antigens presented by major histocompatibility complex (MHC) molecules on antigen-presenting cells. CD4+ helper T cells bind to MHC II molecules and release cytokines that activate other immune cells. CD8+ cytotoxic T cells bind to MHC I and directly kill infected or abnormal cells. Activation requires antigen recognition and co-stimulatory signals.

Antibody-Mediated Immunity

Question: Describe antibody-mediated immunity (antigen presentation, antigen recognition, activation, and cellular response).

In antibody-mediated immunity, B cells recognize specific antigens, often with help from helper T cells. Upon activation, B cells differentiate into plasma cells, which secrete antibodies, and memory B cells for future immunity. These antibodies neutralize pathogens and promote their destruction by other immune cells.

Inhalation and Exhalation Mechanics

Question: Describe the events, pressures, and muscles involved in inhalation and exhalation.

Inhalation involves the diaphragm contracting and flattening, increasing thoracic volume and reducing intrapulmonary pressure, causing air to flow in. Exhalation occurs when the diaphragm relaxes, decreasing volume and increasing pressure, expelling air. Forceful exhalation recruits abdominal and internal intercostal muscles.

Breathing Regulation via Negative Feedback

Question: Describe how breathing is regulated through the negative feedback control of PCO2, PO2, and pH.

Chemoreceptors monitor levels of carbon dioxide (PCO2), oxygen (PO2), and blood pH. Increased PCO2 or decreased pH stimulates the medulla oblongata to increase breathing rate and depth, reducing CO2 levels and restoring pH. Low PO2 also triggers increased ventilation, though this is a weaker stimulus compared to CO2.

Specific vs. Nonspecific Defense

Question: Explain the difference between nonspecific and specific defense and the role of lymphocytes in each immune response.

Nonspecific defenses provide general protection through barriers and phagocytes. Specific defenses involve lymphocytes: T cells mediate cell-mediated immunity, while B cells are central to antibody production. Specific responses are antigen-specific and produce memory cells for long-term immunity.

Components and Functions of the Lymphatic System

Question: Identify the major components of the lymphatic system and explain their functions.

Component	Function
Lymph nodes	Filter lymph, trap pathogens
Lymph vessels	Transport lymph throughout the body
Spleen	Filters blood, recycles old RBCs, supports immune response
Thymus	Site of T cell maturation
Tonsils	Protect against inhaled/ingested pathogens

Nonspecific Defenses and Their Functions

Question: List the body’s nonspecific defenses, and explain the function of two of them, also describe the components and mechanisms.

Nonspecific defenses include skin, mucous membranes, phagocytic cells, inflammation, fever, and natural killer cells. The skin acts as a physical barrier, preventing pathogen entry. Inflammation involves histamine release, vasodilation, and immune cell recruitment to isolate and eliminate pathogens.

Types of T Cells and Their Activation

Question: Discuss the types of T cells and the role played by each in the immune response, and explain the mechanisms of their activation.

T cell types include helper (CD4+), cytotoxic (CD8+), and regulatory T cells. Helper T cells activate immune responses, cytotoxic T cells kill infected cells, and regulatory T cells prevent autoimmunity. Activation occurs through antigen recognition on MHC molecules and co-stimulatory signals from antigen-presenting cells.

B Cell Activation and Differentiation

Question: Describe the mechanisms of B cell activation and the differentiation of plasma cells and memory B cells.

B cells become activated upon binding specific antigens, often with T cell assistance. Once activated, they proliferate and differentiate into:

Cell Type	Function
Plasma Cells	Produce and secrete antibodies
Memory B Cells	Provide rapid response upon re-exposure

These cells are essential for immediate and long-term protection.

Antibody Structure and Functions

Question: Describe the structure of an antibody, and discuss the types and functions of antibodies in body fluids and secretions.

Antibodies have a Y-shaped structure with variable regions that bind to specific antigens and constant regions that determine function. Major classes include:

Antibody Type	Function and Location
IgG	Long-term immunity, blood and extracellular fluid
IgA	Mucosal protection, secretions
IgM	Initial immune response, bloodstream
IgE	Allergy and parasitic defense, skin/mucous membranes
IgD	B cell activation

Respiratory Pathway and Zones

Question: Identify the organs forming the respiratory passageway(s) in descending order until the alveoli are reached. Distinguish between conducting and respiratory zone structures.

The respiratory passageway includes: nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli. The conducting zone (nasal cavity to terminal bronchioles) transports air; the respiratory zone (respiratory bronchioles to alveoli) allows gas exchange.

Pulmonary Ventilation and Lung Volumes

Question: List several physical factors that influence pulmonary ventilation and list the various lung volumes and capacities.

Factors affecting ventilation include airway resistance, lung compliance, and surface tension. Lung volumes and capacities include:

Volume/Capacity	Description
Tidal Volume (TV)	Air exchanged per breath
Inspiratory Reserve (IRV)	Extra air inhaled beyond TV
Expiratory Reserve (ERV)	Extra air exhaled beyond TV
Vital Capacity (VC)	Total air exchangeable (TV + IRV + ERV)
Total Lung Capacity (TLC)	Maximum lung volume after full inhalation

Gas Transport in the Blood

Question: Describe how oxygen and carbon dioxide are transported in the blood.

Oxygen is carried primarily by hemoglobin in red blood cells. Carbon dioxide is transported in three forms: as bicarbonate ions in plasma (70%), bound to hemoglobin (20%), and dissolved in plasma (10%). These mechanisms enable efficient respiratory gas exchange.

Respiratory Disorders

Question: Compare the causes and consequences of conditions such as chronic bronchitis, emphysema, asthma, COPD, ‘black lung,’ and lung cancer.

Chronic respiratory disorders impair gas exchange and airway function:

Condition	Cause	Consequences
Chronic Bronchitis	Smoking, pollution	Excess mucus, persistent cough
Emphysema	Smoking	Alveolar destruction, reduced elasticity
Asthma	Allergens, irritants	Bronchoconstriction, wheezing
COPD	Combination of bronchitis/emphysema	Chronic obstruction of airflow
Black Lung	Coal dust inhalation	Lung scarring, reduced capacity
Lung Cancer	Smoking, toxins	Tumor growth, metastasis

These conditions can severely limit respiratory efficiency and overall health.

BIOS 255 Week 8 Final Exam (Essay & Explanatory)