Exam 4- BIO 224

Respiratory and Digestive

Basic functions of: Conducting Zone?

Filtration, Warmth, Moisturize

Basic functions of: Respiratory Zone?

Gas exchange

Respiration

Pulmonary Ventilation/Breathing

Pulmonary Ventilation

Movement of air in and out of lungs

Pulmonary Gas Exchange

Movement of gases between lungs and blood

Gas Transport

Movement of gases through blood

Tissue Gas Exchange

Movement of gases between blood and tissues

What is considered not respiration?

Speaking, Smelling, Maintaining pH, Regulating internal pressure/Endocrine Function

Bronchioles

Smallest Airways

Simple Cuboidal Epithelium

Enclosed within thick ring of smooth muscles

Conducting zone ends where?

Terminal Bronchioles

What is the flow of the Respiratory System?

Nares→Nasal Cavity→Nasopharynx→Oropharynx→Laryngoparynx→Larynx→Trachea→Primary Bronchi→Secondary Bronchi→Tertiary Bronchi→Multiple Branches of bronchi→Bronchioles→Terminal Bronchioles→Respiratory Bronchioles→Alveolar Ducts→Alveolar Sacs

Type 1 Alveolar Cells

Simple Squamous; 90% of Lung Cells; Rapid Diffusion of gases across cell membranes

Type 2 Alveolar Cells

Simple cuboidal cells; Synthesis of Surfactant to reduce surface tension

Alveolar Macrophages

Mobile phagocytes; clean up and digest debris that made its way to alveolus

Inspiration (Inhalation)

Brings air into lungs

Expiration (Exhalation)

Moves air out of lungs

Boyle’s Law

Pressure and Volume are inversely proportionate

What are the three pressure gradients?

Atmospheric Pressure, Intrapulmonary Pressure, Intrapleural Pressure

Atmospheric Pressure

Molecules of air; pull of gravity on air arounds us creates ATM

Atmospheric pressure at sea level is what?

760mmHg

Intrapulmonary Pressure

Air pressure within alveoli; equalizes with atmospheric pressure between breathes

Intrapleural Pressure

Pressure found within pleural cavity; normally about 4mmHg and less than intrapulmonary pressure

True or False: Intrapleural Pressure equalizes ATM

False

What happens if intrapleural pressure increases to a level at or above atmospheric pressure?

Lungs immediately collapse :(

Pleural Effusion

Excess fluid in pleural space

Pneumothorax

Air enters pleural space

Hemothorax

Blood in pleural space

Physical factors influencing pulmonary ventilation?

Resistance, Surface Tension, Compliance

Resistance

Diameter, controlled by smooth muscle

Bronchodilation

Relaxation of airways (Diameter increases)

Bronchoconstriction

Contraction of airways (Diameter decreases)

Surface Tension

Gas-Water Boundary; where water molecules from hydrogen bonds; gases are nonpolar

When is the Gas-Water Boundary the greatest?

When alveoli are at their smallest diameter during expiration

Surfactant

Opposes surface tension’s collapsing force, has  both polar and non polar end; disrupts water’s ability to hydrogen bond with itself; reduces surface tension and allows alveolus to remain partially open even during expiration

Pulmonary compliance

Ability of lungs and chest wall to stretch

What is pulmonary compliance determined by?

Degree of alveolar surface tension, Distensibility of elastic tissue, Ability of the chest wall to move

Degree of alveolar surface tension

Surfactant counteracts this collapsing force; increases compliance

Distensibility of elastic tissue

Gives lungs the ability to stretch during inflation; increases compliance

Tidal Volume

Volume of air exchanged with normal quiet breathing

Inspiratory reserve volume

Maximum volume of air that can be forcibly inspired after a tidal inspiration

Expiratory Reserve Volume

Maximum volume of air that can be forcibly expired after a tidal expiration

Residual volume

Volume of air that remains in lungs after a forces expiration

Inspiratory Capacity

Total amount of air that can be inspired; equal to TV+IRV

Functional residual capacity

Total amount of air that normally remains in lungs after a tidal expiration; equal to RV+ERV

Vital Capacity

Total amount of exchangeable air; equal to TV+IRV+ERV

Total Lung Capacity

Total amount of exchangeable and nonexchangeable air; equal to IRV+TV+ERV+RV

Minute Volume

TV x Number of breaths per minute

Anatomical Dead Space

Conduction zone

Alveolar Ventilation Rate

Volume of air that reaches alveoli; Minute volume - Dead space

Gas Behavior

Important factor that affects gas exchange; pressure that gas exerts and its solubility in water are important for driving pulmonary and tissue gas exchange

Gas behavior is described by what laws?

Dalton’s Law & Henry’s Law

Dalton’s Law of Partial Pressures

Each gas in mixture exerts is own pressure

Henry’s Law

Degree to which gas dissolves in liquid is proportional to both partial pressure and solubility in liquid

Nitrogen

High partial pressure in air (air is 78% of N₂ by volume); little nitrogen in blood plasma because solubility in water is very low

Oxygen

Lower partial pressure in air than N₂ (Air is 21% O₂ by volume) But dissolved in blood plasma because more soluble in water than nitrogen

Carbon Dioxide

Lowest partial pressure of gases (air is less than 1% CO₂ by volume); Also dissolved in blood plasma as solubility in water is 20 times greater than oxygen

Factors affecting efficiency of Pulmonary Gas Exchange?

Surface area of respiratory membrane, Thickness of respiratory membrane, Ventilation-Perfusion Matching

Surface are of respiratory membrane

Both lungs is extremely large while quantity of blood in pulmonary capillaries is only 75-100mL

True or False: Any factor that reduces surface area decreases efficiency of pulmonary gas exchange?

True

Thickness of respiratory membrane

Distance that gas must diffuse

True or False: Anything that increases thickness of membrane, like inflammation, will diminish gas exchange efficiency by increasing the time it takes for gases to diffuse

True

Internal Respiration

Tissue gas exchange; exchange of oxygen and CO₂ between blood and tissues; partial pressure of oxygen and carbon dioxide in systemic capillaries and tissues provide pressure gradients that drive diffusion of gases

Factors affecting efficiency of tissue gas exchange?

Surface area available for gas exchange; Distance over which diffusion must occur; Perfusion of tissue

Hypoxemia

Low blood oxygen level

Hypercapnia

High blood Carbon Dioxide level

True or False: Only 1.5% of inspired oxygen is dissolved in blood plasma due to its poor solubility

True

Oxygen is transported in blood plasma by what?

Hemoglobin (Hb)

Loading

Oxygen from alveoli binds to Hb in pulmonary capillaries; converts deoxyhemoglobin to oxyhemoglobin

Unloading

Hb in systemic capillaries releases oxygen to cells of tissues

Carbonic Acid-Bicarbonate Buffer System

One of primary buffer systems in body pH of blood changes very little from normal 7.35-7.45

When pH _____, H⁺ binds with buffers like bicarbonate making carbonic acid

Decreases

When pH _____, same reaction generates H⁺ that decreases pH

Increases

Hypocapnia

Relative lack of CO₂

Hypercapnia

Increase in CO₂ level

Respiratory Acidosis

Can occur if hypoventilation continues

Respiratory Alkalosis

Can occur if hyperventilation continues

Breathing

Usually occurs wi0htout conscious thought or control

Dyspnea

Feeling of shortness of breath; may be a result of many different causes

Eupnea

Normal breathing

Is breathing a negative or positive feed back loop?

Negative feedback loop

Restrictive Lung Diseases

Decrease pulmonary compliance and reduce effectiveness of inspiration by increasing alveolar surface tension and destroying elastic tissue of lungs

Idiopathic Pulmonary Fibrosis

Causes chronic inflammation of lung tissue with eventual destruction of elastic tissue and its subsequent replacement with thick collagen fiber bundles; cause is unknown; associated with heavy smoking

Pneumoconiosis

Group of diseases that arise from inhalation or inorganic dust particles including coal, asbestos, fiberglass, and some heavy metals; particles cause inflammation followed by fibrosis

Neuromuscular diseases and chest wall deformities

Not purely lung disease; potential consequence is pulmonary dysfunction by causing weak inspiratory musculature of stiff chest wall

Obstructive lung diseases

Increases airway resistance; decreases efficiency of expiration

Chronic Obstructive Pulmonary Disease (COPD)

Defined as persistent airway obstruction that is NOT fully reversible

Emphysema

Characterized by destruction of structures of respiratory zone and loss of alveolar surface area; most cases are due to smoking

Small Airway Disease

Bronchioles narrow and are typically plugged wit mucus; commonly associated with emphysema

Chronic Bronchitis

Characterized by excessive mucus in airways that must be cleared by coughing; caused exclusively by cigarette smoke

Increase in Number and Size of goblet cells, mucous glands, and paralysis of cilia is caused by what?

Chronic Bronchitis

Asthma

Obstructive disease in which airways are hyperresponsive to variety of triggers (dust mites, mold, pollen, dander)

Bronchoconstriction

Inflammation of airways, and increased production of excessively thick mucus

Lung Cancer

Refers to tumors arising from epithelium that lines bronchi, bronchioles, and alveoli

What is the #1 risk factor for lung cancer?

Cigarette Smoking

True or False: Passive and/or second-hand smoke increases risk of developing lung cancer by about one and a half times that of nonsmoker

True