Chapter 9

Biology 25: Human BiologyBiology 25: Human Biology

Prof. GonsalvesProf. Gonsalves

Los Angeles City CollegeLos Angeles City College

Loosely Based on Mader’s Loosely Based on Mader’s Human Human BiologyBiology,7,7thth edition edition

Human Respiratory SystemHuman Respiratory SystemFunctions:Functions:

Works closely with circulatory system, Works closely with circulatory system, exchanging gases between air and blood:exchanging gases between air and blood:Takes up oxygen from air and supplies it to Takes up oxygen from air and supplies it to

blood (for cellular respiration).blood (for cellular respiration).Removal and disposal of carbon dioxide Removal and disposal of carbon dioxide

from blood (waste product from cellular from blood (waste product from cellular respiration).respiration).

Homeostatic Role:Homeostatic Role: Regulates blood pH.Regulates blood pH. Regulates blood oxygen and carbon dioxide Regulates blood oxygen and carbon dioxide

levels.levels.

Blood Transports Gases Between Lungs and Tissues

Human Respiratory SystemHuman Respiratory SystemComponents: Components: Nasal cavity, throat (pharynx), larynx (voice box), Nasal cavity, throat (pharynx), larynx (voice box),

trachea, bronchi, alveoli, and lungs.trachea, bronchi, alveoli, and lungs.Pathway of Inhaled Air: Pathway of Inhaled Air: Nasal cavityNasal cavity Pharynx Pharynx (Throat)(Throat) Larynx Larynx (Voice Box)(Voice Box) Trachea Trachea (Windpipe)(Windpipe) BronchiBronchi BronchiolesBronchioles Alveoli Alveoli ((Site of gas exchangeSite of gas exchange))

Exhaled air follows reverse pathway.Exhaled air follows reverse pathway.

Human Respiratory SystemHuman Respiratory System1. Nasal cavity: 1. Nasal cavity: Air enters nostrils, is filtered by hairs, warmed, Air enters nostrils, is filtered by hairs, warmed,

humidified, and sampled for odors as it flows through a maze of humidified, and sampled for odors as it flows through a maze of spaces. spaces.

2. Pharynx (Throat):2. Pharynx (Throat): Intersection where pathway for air and food Intersection where pathway for air and food cross. Most of the time, the pathway for air is open, except when cross. Most of the time, the pathway for air is open, except when we swallow.we swallow.

3. Larynx (Voice Box):3. Larynx (Voice Box): Reinforced with cartilage. Contains Reinforced with cartilage. Contains vocal vocal cordscords, which allow us to make sounds by voluntarily tensing , which allow us to make sounds by voluntarily tensing muscles.muscles. High pitched sounds:High pitched sounds: Vocal cords are tense, vibrate fast. Vocal cords are tense, vibrate fast. Low pitched sounds:Low pitched sounds: Vocal cords are relaxed, vibrate slowly. Vocal cords are relaxed, vibrate slowly. More prominent in males (More prominent in males (Adam’s appleAdam’s apple).).

Human Respiratory SystemHuman Respiratory System4. Trachea (Windpipe): 4. Trachea (Windpipe): Rings of cartilage maintain shape Rings of cartilage maintain shape

of trachea, to prevent it from closing. Forks into two of trachea, to prevent it from closing. Forks into two bronchi.bronchi.

5. Bronchi5. Bronchi (Sing. Bronchus):(Sing. Bronchus): Each bronchus leads into a Each bronchus leads into a lung and branches into smaller and smaller lung and branches into smaller and smaller bronchiolesbronchioles, resembling an inverted tree. , resembling an inverted tree.

6. Bronchioles:6. Bronchioles: Fine tubes that allow passage of air. Fine tubes that allow passage of air. Muscle layer constricts bronchioles. Epithelium of Muscle layer constricts bronchioles. Epithelium of bronchioles is covered with cilia and mucus.bronchioles is covered with cilia and mucus. Mucus traps dust and other particles.Mucus traps dust and other particles. Ciliary EscalatorCiliary Escalator: Cilia beat upwards and remove : Cilia beat upwards and remove

trapped particles from lower respiratory airways. trapped particles from lower respiratory airways. Rate about 1 to 3 cm per hour.Rate about 1 to 3 cm per hour.

Pulmonary Function Tests

Assessed by spirometry.Assessed by spirometry. Subject breathes into a closed system in Subject breathes into a closed system in

which air is trapped within a bell floating which air is trapped within a bell floating in Hin H220.0.

The bell moves up when the subject The bell moves up when the subject exhales and down when the subject inhales.exhales and down when the subject inhales.

Spirogram Tidal volume: Tidal volume: Amount of air expired with each breath.Amount of air expired with each breath. Vital capacity:Vital capacity: The maximum amount of air that can be forcefully The maximum amount of air that can be forcefully

exhaled after maximum inhalation.exhaled after maximum inhalation.

Table 16.3 Terms Used to Describe Lung Volumes and Capacities

Term DefinitionLung Volumes The four nonoverlapping components of the total lung

capacity Tidal volume The volume of gas inspired or expired in an unforced

respiratory cycle Inspiratory reserve volume The maximum volume of gas that can be inspired during

forced breathing in addition to tidal volume Expiratory reserve volume The maximum volume of gas that can be expired during

forced breathing in addition to tidal volume Residual volume The volume of gas remaining in the lungs after a maximum

expirationLung Capacities Measurements that are the sum of two or more lung volumes Total lung capacity The total amount of gas in the lungs after a maximum

inspiration Vital capacity The maximum amount of gas that can be expired after a

maximum inspiration Inspiratory capacity The maximum amount of gas that can be inspired after a

normal tidal expiration Functional residual capacity The amount of gas remaining in the lungs after a normal tidal

expiration

Anatomical Dead Space Not all of the inspired air reached the alveoli.Not all of the inspired air reached the alveoli. As fresh air is inhaled it is mixed with anatomical As fresh air is inhaled it is mixed with anatomical

dead space.dead space. Conducting zone and alveoli where 0Conducting zone and alveoli where 022

concentration is lower than normal and C0concentration is lower than normal and C022 concentration is higher than normal.concentration is higher than normal.

Alveolar ventilation: f x (TV- DS)Alveolar ventilation: f x (TV- DS) F = frequency (breaths/min.).F = frequency (breaths/min.). TV = tidal volume.TV = tidal volume. DS = dead space.DS = dead space.

Restrictive and Obstructive Disorders

Restrictive Restrictive disorder:disorder: Vital capacity is Vital capacity is

reduced. reduced. FVC is normal.FVC is normal.

Obstructive Obstructive disorder:disorder: VC is normal.VC is normal. FEVFEV11 is is

reduced.reduced.

Breathing Ventilates the LungsBreathing Ventilates the LungsBreathing:Breathing: Alternation of inhalation and exhalation. Supplies our Alternation of inhalation and exhalation. Supplies our

lungs with oxygen rich air, and expels excess carbon dioxide.lungs with oxygen rich air, and expels excess carbon dioxide. Inhalation:Inhalation: Diaphragm contracts, moving downward and Diaphragm contracts, moving downward and

causing rib cage, chest cavity, and lungs to expand. Air rushes causing rib cage, chest cavity, and lungs to expand. Air rushes in, due to decrease in internal lung pressure as lungs expand.in, due to decrease in internal lung pressure as lungs expand.

Exhalation:Exhalation: Diaphragm relaxes, moving upwards and causing Diaphragm relaxes, moving upwards and causing rib cage, chest cavity, and lungs to contract. Air rushes out, rib cage, chest cavity, and lungs to contract. Air rushes out, due to the increase in internal lung pressure as lungs contract.due to the increase in internal lung pressure as lungs contract.Breathing is controlled by centers in the nervous system to Breathing is controlled by centers in the nervous system to keep up with body’s demands.keep up with body’s demands.

Hemoglobin helps transport COHemoglobin helps transport CO22 and buffer blood and buffer blood

Hemoglobin is found in red blood cellsHemoglobin is found in red blood cellsFunctions:Functions:

Transports oxygenTransports oxygen Transport carbon dioxideTransport carbon dioxide Helps buffer bloodHelps buffer blood

As carbon dioxide is picked up from tissues it is converted As carbon dioxide is picked up from tissues it is converted into carbonic acid:into carbonic acid:

COCO22 + H + H22O <-----> HO <-----> H22COCO33 <----> H <----> H++ + HCO + HCO3 3 --

Carbon Carbon Carbonic acidCarbonic acid Carbonate ion Carbonate iondioxidedioxide

Hemoglobin picks up most H Hemoglobin picks up most H ++ ions, so they don’t acidify the ions, so they don’t acidify the blood.blood.

Hemoglobin Loading and Unloading of Oxygen

Respiratory Acid-Base Balance

Ventilation normally adjusted to keep Ventilation normally adjusted to keep pace with metabolic rate.pace with metabolic rate.

HH22COCO33 produced converted to CO produced converted to CO22, , and excreted by the lungs.and excreted by the lungs.

HH220 + C00 + C022 H H22C0C033 H H+ + + HC0+ HC033--

Respiratory Acidosis

Hypoventilation.Hypoventilation. Accumulation of COAccumulation of CO2 2 in the tissues.in the tissues. pH decreases.pH decreases. Plasma HCOPlasma HCO33

-- increases. increases. PPc02c02 increases. increases.

Respiratory Alkalosis

Hyperventilation.Hyperventilation. Excessive loss of COExcessive loss of CO22.. pH increases.pH increases. Plasma HCOPlasma HCO33

-- decreases. decreases. PPc02c02 decreases. decreases.

Diseases of the Respiratory SystemDiseases of the Respiratory System Respiratory rate: 10 to 14 inhalations/minute.Respiratory rate: 10 to 14 inhalations/minute. In one day, an average human:In one day, an average human:

Breathes 20,000 timesBreathes 20,000 times Inhales 35 pounds of airInhales 35 pounds of air

Most of us breathe in air that is heavily contaminated with Most of us breathe in air that is heavily contaminated with solid particles, ozone, sulfur oxide, carbon monoxide, solid particles, ozone, sulfur oxide, carbon monoxide, nitrogen oxides, and many other damaging chemicals.nitrogen oxides, and many other damaging chemicals.

Breathing contaminated air can cause a number of diseases Breathing contaminated air can cause a number of diseases including asthma, bronchitis, emphysema, and lung cancer.including asthma, bronchitis, emphysema, and lung cancer.

Diseases of the Respiratory SystemDiseases of the Respiratory System Respiratory rate: 10 to 14 inhalations/minute.Respiratory rate: 10 to 14 inhalations/minute. In one day, an average human:In one day, an average human:

Breathes 20,000 timesBreathes 20,000 times Inhales 35 pounds of airInhales 35 pounds of air

Most of us breathe in air that is heavily contaminated with Most of us breathe in air that is heavily contaminated with solid particles, ozone, sulfur oxide, carbon monoxide, solid particles, ozone, sulfur oxide, carbon monoxide, nitrogen oxides, and many other damaging chemicals.nitrogen oxides, and many other damaging chemicals.

Breathing contaminated air can cause a number of diseases Breathing contaminated air can cause a number of diseases including asthma, bronchitis, emphysema, and lung cancer.including asthma, bronchitis, emphysema, and lung cancer.

Diseases of the Respiratory SystemDiseases of the Respiratory System Cigarette smoke is one of the worse air pollutants.Cigarette smoke is one of the worse air pollutants.

Over 1 million people start smoking every year.Over 1 million people start smoking every year. Kills about 350,000 people every year in U.S.Kills about 350,000 people every year in U.S. Contains 4000 different chemicals.Contains 4000 different chemicals. Each cigarette smoked subtracts about 5 Each cigarette smoked subtracts about 5

minutes from life expectancy.minutes from life expectancy. Cigarette smoke Cigarette smoke paralyzes ciliaparalyzes cilia in airways, in airways,

preventing them from removing debris and preventing them from removing debris and from protecting delicate alveoli.from protecting delicate alveoli.

Frequent coughing is the only way airways can Frequent coughing is the only way airways can clean themselves.clean themselves.

Cigarette smoke also causes fetal damage, which Cigarette smoke also causes fetal damage, which can result in miscarriage, premature birth, low can result in miscarriage, premature birth, low birth weight, and poor development.birth weight, and poor development.

Diseases of the Respiratory SystemDiseases of the Respiratory System Asthma:Asthma: Condition in which breathing is impaired by Condition in which breathing is impaired by

constriction of bronchi and bronchioles, cough, and constriction of bronchi and bronchioles, cough, and thick mucus secretions. The severity and incidence of thick mucus secretions. The severity and incidence of asthma has risen dramatically in recent years, asthma has risen dramatically in recent years, especially in children. May be fatal if not treated.especially in children. May be fatal if not treated.Causes:Causes: Attacks may be precipitated by inhalation of Attacks may be precipitated by inhalation of allergens (e.g.: pollen, cats, and cockroach proteins), allergens (e.g.: pollen, cats, and cockroach proteins), pollutants, infection, or emotional stress.pollutants, infection, or emotional stress.Treatment:Treatment: Alleviates symptoms (e.g.: immuno- Alleviates symptoms (e.g.: immuno-suppressors, bronchodilators), but is not a cure.suppressors, bronchodilators), but is not a cure.

Diseases of the Respiratory SystemDiseases of the Respiratory System Bronchitis:Bronchitis: Inflammation of the mucous membranes of the Inflammation of the mucous membranes of the

bronchi. May present with cough, fever, chest or back bronchi. May present with cough, fever, chest or back pain, and fatigue.pain, and fatigue.Causes:Causes: Associated with smoking, pollution, and bacterial Associated with smoking, pollution, and bacterial or viral infections.or viral infections.

Pneumonia:Pneumonia: Acute inflammation of the lungs. Symptoms Acute inflammation of the lungs. Symptoms include high fever, chills, headache, cough, and chest pain. include high fever, chills, headache, cough, and chest pain. Causes: Causes: Bacterial, fungal, or viral infections.Bacterial, fungal, or viral infections.Treatment:Treatment: Antibiotics or other antimicrobials. Antibiotics or other antimicrobials.

Diseases of the Respiratory SystemDiseases of the Respiratory System Emphysema:Emphysema: Permanent and irreversible Permanent and irreversible

destruction of alveolar walls, resulting in loss of destruction of alveolar walls, resulting in loss of lung elasticity and gas exchange surface. lung elasticity and gas exchange surface. Symptoms include shortness of breath, difficulty Symptoms include shortness of breath, difficulty exhaling, cough, weakness, anxiety, confusion, exhaling, cough, weakness, anxiety, confusion, heart failure, lung edema (swelling), and heart failure, lung edema (swelling), and respiratory failure.respiratory failure.Causes:Causes: SmokingSmoking, pollution, old age, and infections., pollution, old age, and infections.Treatment:Treatment: Oxygen to help breathing. No cure. Oxygen to help breathing. No cure.

Diseases of the Respiratory SystemDiseases of the Respiratory System Lung Cancer:Lung Cancer: Cancerous growth that invades and destroys Cancerous growth that invades and destroys

lung tissue. Very high fatality rate. lung tissue. Very high fatality rate. Symptoms include bloody sputum, persistent cough, Symptoms include bloody sputum, persistent cough, difficulty breathing, chest pain, and repeated attacks of difficulty breathing, chest pain, and repeated attacks of bronchitis or pneumonia.bronchitis or pneumonia.Causes:Causes: Smoking Smoking (50% of all cases) and pollution (radon, (50% of all cases) and pollution (radon, asbestos). Smokers are 10 times more likely to develop asbestos). Smokers are 10 times more likely to develop lung cancer than nonsmokers.lung cancer than nonsmokers.Treatment:Treatment: Surgery is most effective, but only 50% of all Surgery is most effective, but only 50% of all lung cancers are operable by time of detection. Other lung cancers are operable by time of detection. Other treatments include radiation and chemotherapy.treatments include radiation and chemotherapy.

Human Fetus Exchanges Gases with Mother’s Blood through the Placenta