BIO-241 UNCW Exam 2

What is the main purpose of the respiratory system?

To supply the body with O2 and dispose of CO2.

What are the 4 events/processes of respiration?

1. Pulmonary ventilation, 2. External respiration, 3. Transport of respiratory gases, 4. Internal respiration

What is pulmonary ventilation?

Moving air in and out of the lungs.

What happens during external respiration?

Oxygen loading and CO2 unloading in the lungs.

What happens during internal respiration?

CO2 loading and oxygen unloading at the systemic tissues.

What structures make up the Conducting Zone?

Nose, Pharynx, Larynx, Trachea, Bronchi.

What are the functions of the Conducting Zone?

Allow air to reach the site of gas exchange; filter, warm, and humidify air.

What structures make up the Respiratory Zone?

Bronchioles, Alveoli, Lungs, and respiratory muscles (Diaphragm).

What is the primary function of the Respiratory Zone?

It is the actual site of gas exchange.

What are the functions of the nose and paranasal sinuses?

Air passage, warming, filtration, resonance for speech, and olfaction.

What forms the external nose?

Frontal/nasal bones and cartilages.

What forms the roof and floor of the nasal cavity?

Roof: Ethmoid and sphenoid bones. Floor: Hard and soft palate.

What epithelial tissue lines the nasal cavity?

Pseudostratified ciliated columnar epithelium.

What are the functions of the paranasal sinuses, and where are they located?

Functions: Produce mucus, warm/moisten air, and lighten the skull. Locations: Ethmoid, sphenoid, frontal, and maxillae bones.

What is the pharynx, and what are its three divisions?

The throat (connects nasal/oral cavities to larynx). Divisions: Nasopharynx, Oropharynx, Laryngopharynx.

What is the larynx and what are its 3 main functions?

The voice box (connects laryngopharynx & trachea). Functions: 1. Provides an open airway, 2. Acts as a switching mechanism for air/food, 3. Voice production.

What happens upon swallowing in the larynx?

The epiglottis closes over the larynx.

How is voice produced in the larynx?

Vocal ligaments/folds flank the glottis; air forced through the glottis causes vibration of vocal folds, resonance in cavities/sinuses, and shaping by tongue and lips.

What is the trachea and what lines it?

Flexible windpipe extending from larynx then splitting into left/right primary bronchi; lined with epithelia/mucosa to clean and moisten air.

What structures make up the conducting portion of the bronchial tree?

Primary, secondary, and tertiary bronchi; bronchioles and terminal bronchioles.

How do walls and epithelium change as the bronchial tree branches further down?

Becomes less rigid (less cartilaginous), and epithelium changes from columnar to cuboidal.

What structures make up the respiratory portion of the bronchial tree?

Respiratory bronchioles leading into alveolar ducts, alveolar sacs, and alveoli.

Compare the anatomical lobes of the Right and Left lungs.

Right lung: 3 lobes (larger). Left lung: 2 lobes and contains a cardiac notch.

What provides blood supply to the lungs?

Pulmonary arteries, capillaries, & veins (for gas exchange); Bronchial arteries (systemic blood supply to lung tissue).

What are the two pleural membranes?

Visceral pleura (inner) and parietal pleura (outer) serous membranes.

What is Intrapulmonary / Intra-alveolar pressure?

Pressure inside the lungs that rises/falls and equalizes with atmospheric pressure.

What is Intrapleural pressure, and why is it important?

Pressure in the pleural cavity that rises/falls but always remains negative relative to intrapulmonary pressure; prevents lungs from collapsing.

How is negative intrapleural pressure maintained?

By the tight fit of the visceral and parietal pleura.

What is the relationship between gas volume and gas pressure (Boyle's Law concept)?

Gas pressure varies inversely with gas volume.

What sequence of physical changes causes gas flow in breathing?

Volume changes -> Pressure changes -> Flow of gases.

What muscles are involved in inspiration and what happens to thoracic volume/pressure?

Diaphragm and external intercostals contract; chest cavity expands, pressure drops, air rushes in.

Why is normal quiet expiration considered passive?

Driven by natural elasticity of lungs; decrease in size causes a rise in pressure, leading to outflow of air.

What device measures respiratory status?

Spirometer.

Define Tidal Volume (TV) and its typical value.

Amount of air inhaled or exhaled in one breath during quiet breathing (500 mL).

Define Inspiratory Reserve Volume (IRV) and its typical value.

Amount of air in excess of tidal volume that can be inhaled with maximum effort (3,000 mL).

Define Expiratory Reserve Volume (ERV) and its typical value.

Amount of air in excess of tidal volume that can be exhaled with maximum effort (1,200 mL).

Define Residual Volume (RV) and its purpose.

Air remaining in lungs after maximum expiration (1,300 mL); prevents lung collapse.

Define Vital Capacity (VC) and give its formula.

Total exchangeable air (4,700 mL); VC = TV + IRV + ERV.

Define Total Lung Capacity (TLC) and give its formula.

Maximum air lungs can contain (6,000 mL / 6L); TLC = VC + RV.

What is Dead Space?

Unused air in passageways that does not undergo gas exchange.

What is Total Ventilation at rest?

Volume x Rate = Gas exchanged per minute (approx. 6 L/min at rest).

What are the 4 layers/components of the respiratory membrane?

1. Surfactant, 2. Alveolar epithelial cell, 3. Fused basement membrane, 4. Capillary endothelial cell

What is the function of surfactant in the alveoli?

Lowers surface tension.

How do bulk flow and diffusion differ in gas exchange?

Bulk flow moves dissolved gases in bulk; diffusion moves gases across tissue membranes.

Compare solubility of CO2, O2, and N2 in plasma.

CO2 is very soluble; O2 is 1/20th as soluble as CO2; N2 is insoluble.

How does alveolar gas composition compare to atmospheric air?

Alveolar gas is a mixture of in & out breaths; higher in CO2 and water vapor than atmospheric air.

What 3 physical factors influence pulmonary gas exchange?

1. Partial pressure gradients & gas solubility, 2. Ventilation-perfusion coupling, 3. Respiratory membrane structure

Explain Ventilation-Perfusion Coupling.

Close match between ventilation (air supply) and blood flow; high CO2 pressure in alveoli causes bronchodilation.

How does respiratory membrane structure aid gas exchange?

It is extremely thin and has an enormous surface area.

How is oxygen transported in the blood?

98.5% carried bound to hemoglobin; remaining 1.5% dissolved in plasma.

How many oxygen molecules can each hemoglobin carry?

4 oxygen molecules.

What speeds up oxygen unloading at systemic tissues?

Low pH (high CO2 concentration) and high temperatures in working muscles.

What 3 forms transport CO2 in the blood and their percentages?

1. Dissolved in plasma (10%), 2. Bound to hemoglobin / carbaminohemoglobin (~20%), 3. Bicarbonate ion (HCO3-) in plasma (~70%).

Write the chemical equation for CO2 reacting with water in RBCs.

CO2 + H2O

What role do H+ ions play in systemic gas transport?

Released H+ ions lower blood pH, absorb pH changes in RBC, and enhance O2 binding/unloading.

Where is respiratory rhythm set, and what are its two primary groups?

Set in the medulla. Dorsal Respiratory Group (DRG = "inspiratory center") and Ventral Respiratory Group (VRG).

What muscles do medullary respiratory centers innervate?

Diaphragm and intercostal muscles.

What two centers in the Pons fine-tune/modify breathing?

Pneumotaxic center (checks/fine-tunes inspiration) and Apneustic center (stimulates DRG).

What trigger stops inspiration during the Inflation Reflex?

Stretch receptors in lungs trigger signals to cease inspiration.

How do the Hypothalamus and Cerebral Cortex modify breathing?

Hypothalamus: responds to emotions, pain, temperature. Cerebral Cortex: voluntary control that bypasses medulla until CO2 becomes too high.

How do chemical factors adjust rate and depth of breathing?

Chemoreceptors in brain & blood vessels sense O2, CO2, and H+ (pH) levels; hyperventilation flushes CO2, while hypoventilation lets CO2 rise.

How does breathing adjust during exercise?

Depth of breathing increases to match needs (driven by conscious anticipation & co-stimulation of skeletal muscles/respiratory center).

What short-term acclimatization occurs at high altitude?

Increased ventilation due to lower air/O2 pressure; O2 carrying capacity drops but unloading becomes more efficient.

Define Lung Compliance and state two factors it depends on.

Ease with which lungs and thoracic wall expand; depends on: 1. Elasticity, 2. Surface tension.

What four conditions decrease lung compliance?

1. Destroys lung tissue (emphysema), 2. Fills lungs with fluid (pneumonia), 3. Deficiency of surfactant (premature birth, near-drowning), 4. Interferes with expansion (pneumothorax)

Characterize COPD (Emphysema and Chronic Bronchitis).

Airway obstruction, coughing/infections, respiratory failure; emphysema causes loss of alveolar elasticity obstructing expiration; chronic bronchitis causes overproduction of mucus.

Define Asthma.

Airway inflammation triggered by an immune response to allergens.

What are the 3 main functions of the Lymphatic System?

1. Return interstitial fluid to the blood (called "lymph" inside vessels), 2. Transport dietary lipids, 3. Defend/resist disease (immune surveillance)

Describe the flow pattern and pressure of the lymphatic system.

One-way flow of fluid toward the heart through a low-pressure transport system (similar to veins).

What are the unique structural features of lymphatic capillaries?

Intertwined with circulatory capillary beds, dead-ended, and highly permeable (absorb proteins, debris, pathogens).

What constitutes Lymph fluid?

Interstitial fluid + escaped plasma proteins.

What three mechanisms drive the one-way flow of lymph?

a. One-way valves, b. Skeletal muscle pump, c. Respiratory pump.

Trace the pathway of lymph through vessel types.

Lymphatic capillaries -> Lymphatic vessels -> Lymph nodes -> Lymph trunks -> Ducts -> Subclavian veins.

List the primary Lymphoid Cells and their basic functions.

Neutrophils, Natural Killer (NK) cells, T & B Lymphocytes (attack cells/secrete antibodies), Macrophages (engulf invaders), Dendritic cells (Antigen-presenting cells).

What types of tissue make up Lymphoid Tissues?

Reticular (loose) connective tissue, Mucosa-associated lymphoid tissue (MALT), and Lymphoid nodules.

Name 5 primary/secondary Lymphoid Organs and their core functions.

1. Red bone marrow (cell origin), 2. Spleen (cleans blood, removes old RBCs/platelets, stores iron/platelets), 3. Thymus (hormonally activates T cells for immunocompetence), 4. Tonsils (remove airborne pathogens), 5. Lymph nodes

What are the 2 major functions of Lymph Nodes?

1. Filtration (phagocytose debris/microorganisms), 2. Immune activation (T/B lymphocytes monitor foreign antigens)

Describe internal lymph node structure and flow direction.

Cortex (dividing/circulating T cells), Medulla (lymph sinuses with lymphocytes/macrophages); Fluid enters via afferent vessels, passes through sinuses, exits at hilus via efferent vessels.

Name the 4 main anatomical regions of lymph node concentrations.

Cervical (head/neck), Axillary (upper extremity/breast), Inguinal (lower extremities), Abdominal (viscera/along aorta).

Compare Innate System vs. Adaptive System.

Innate: Non-specific, always prepared (1st & 2nd lines of defense). Adaptive: Specific, requires prior exposure before attack (3rd line of defense).

What makes up the First Line of Defense?

Mechanical surface barriers: Intact skin, mucous membranes, secretions (low pH of skin, stomach acid/enzymes, saliva/tears, mucus).

What cells serve as Phagocytes and what are the steps of phagocytosis?

Monocytes, Macrophages, Neutrophils, Eosinophils, Dendritic cells. Steps: Adherence -> Engulfment -> Digestion/destruction.

What are Natural Killer (NK) cells and how do they function?

Large non-specific lymphocytes that kill cancer cells and virus-infected cells by releasing cytolytic enzymes.

What is the purpose of Inflammation and its four cardinal signs?

Prevents spread of damage, disposes of debris/pathogens, activates repair. Signs: Redness, heat, swelling, pain.

Describe the cellular events during Inflammation.

Chemical alarm (histamine/kinins) released -> Vasodilation (increases blood flow) -> Capillary permeability (edema/pain) -> Neutrophil diapedesis & chemotaxis to mobilize phagocytes.

What are Interferons and Complement proteins?

Interferons: Secreted proteins warning uninfected cells and activating NK cells/macrophages. Complement: Plasma globulins forming a Membrane Attack Complex (MAC) to lyse cells, facilitate destruction, and enhance inflammation.

How is Fever produced and why is it beneficial?

Pyrogens secreted by WBCs reset hypothalamus set point to higher temperature. Benefits: Inhibits bacterial/viral replication, promotes interferon, speeds repair.

What are the 3 key features of an Adaptive Immune Response?

1. Antigen-specific, 2. Systemic, 3. Has Memory (stronger subsequent attack)

What is a Complete Antigen vs. Incomplete Antigen (Hapten)?

Complete: Has Immunogenicity (stimulates lymphocytes) and Reactivity. Hapten: Small non-immunogenic molecule that becomes reactive only after binding to body carrier proteins.

What are Antigenic Determinants (Epitopes)?

The specific immunogenic portions of an antigen that activate different populations of lymphocytes.

Differentiate Class I MHC vs. Class II MHC proteins.

Class I: On ALL nucleated body cells (alerts Cytotoxic T cells if altered). Class II: On "professional" Antigen-Presenting Cells (APCs) (interacts with Helper T cells).