Survey of Anatomy & Physiology Chap 13

The Respiratory System: It's a Gas

13

Respiratory SystemRespiratory System

Respiratory system's primary function: to transport oxygen from atmosphere to bloodstream to be utilized by cells, tissues, organs for process of cellular respiration, which is necessary to sustain life

Respiratory SystemRespiratory System

Respiratory system moves 12,000 quarts of air per day in and out of lungs

Respiratory system removes waste gas—carbon dioxide—so it doesn't build up in toxic levels

Cellular Respiration Cellular Respiration Needs OxygenNeeds Oxygen

Cellular respiration depends on continuous supply of oxygen, found in abundance in air we breathe

Using oxygen produces carbon dioxide, which would become toxic if allowed to build in bloodstream; must be removed

Cardiopulmonary SystemCardiopulmonary System

Respiratory system closely related to heart and circulatory system; they are sometimes grouped together as cardiopulmonary system

Anatomy of Respiratory Anatomy of Respiratory SystemSystem

Components of respiratory system:

Two lungs that serve as vital organs

Upper and lower airways that conduct gas in and out of the system

Terminal air sacs called alveoli surrounded by network of capillaries that provide for gas exchange

Anatomy of Respiratory Anatomy of Respiratory SystemSystem

Components of respiratory system:

Thoracic cage that houses, protects, facilitates function for the system

Muscles of breathing that include the main muscle, the diaphragm, and accessory muscles

Figure 13-1Figure 13-1The various components of The various components of the respiratory systemthe respiratory system

http://www.youtube.com/watch?v=hc1YtXc_84A

Watch Video on “Respiratory

System”

Ventilation versus Ventilation versus RespirationRespiration


Ventilation: bulk movement of air into and out of lungs where gas exchange takes

place


Respiration: process of gas

exchange, where oxygen added to blood and carbon dioxide removed

External Respiration External Respiration versus Internal versus Internal RespirationRespiration


External respiration: gas exchange in lungs

occurs between blood and air in the

external atmosphere


Internal respiration:

oxygenated blood transported

internally via cardiovascular

system to cells and tissues; oxygen

moves into cells as carbon dioxide

removed

Table 13-1Table 13-1 Gases in the Gases in the AtmosphereAtmosphere

Air contains many gases,

predominantly nitrogen, which is a support gas that keeps lungs open with its constant volume and pressure

Table 13-1Table 13-1 Gases in the Gases in the AtmosphereAtmosphere

Next highest concentration found in air is oxygen, essential to life; carbon dioxide is

found in very small

concentrations

Figure 13-2Figure 13-2Contrast of ventilation and Contrast of ventilation and

external and internal external and internal respirationrespiration

We have reserve of

oxygen to last 4 to 6

minutes; after that we will die if we

don't get more oxygen

The Airways and LungsThe Airways and Lungs

Respiratory system is series of branching tubes called bronchi and bronchioles


Airways transport atmospheric gas deep within lungs to small air sacs called alveoli, which represent terminal end of respiratory system


Each alveolus is surrounded by capillaries; combination called alveolar-capillary membrane; represents connection between respiratory and cardiovascular systems

Structures of Upper Structures of Upper AirwayAirway

Function of Upper Airway Function of Upper Airway StructuresStructures

Mouth

Nose

Larynx

Pharynx

Figure 13-3The upper airway and vocal

cords

Upper Airways of Upper Airways of Respiratory TractRespiratory Tract

While some people breathe through their mouths, we are meant to breathe through our noses

Rigid structure made of cartilage and bone

Upper Airways of Upper Airways of Respiratory TractRespiratory Tract

Nasal cavity: behind nose, divided into three main regions

Vestibular

Olfactory

Respiratory

Figure 13-4Figure 13-4The nasal regionsThe nasal regions

Regions of the NoseRegions of the Nose

Three Main Regions

Vestibular Region of Vestibular Region of NoseNose

Vestibular region: located inside nostrils and contains coarse nasal hairs that act as first line of defense for respiratory system

These hairs (vibrissae) covered with sebum, greasy substance secreted by sebaceous glands of nose

Sebum helps trap particles; keeps hairs soft and pliable

Olfactory Region of Olfactory Region of NoseNose

Olfactory region: located on roof of nasal cavity, allowing air to be held there so it can be sampled

Respiratory Region of Respiratory Region of NoseNose

Respiratory region

Air warmed to body temperature and moistened in this region inside nasal cavity, which is lined with mucous membranes and richly supplied with blood

There are three scroll-like bones (turbinates) that split incoming air into three channels, providing more surface area

Respiratory Region of Respiratory Region of NoseNose

Respiratory region

Turbinates serve to make incoming air current more turbulent, bringing more air in contact with mucous membranes for warming and moisture, adding 650 to 1,000mLs of water each day to moisten air to 80% relative humidity

Mucociliary ElevatorMucociliary Elevator

Cells in epithelial lining of airways of respiratory system are called pseudostratified ciliated columnar cells

Consists of single layer of tall columnlike cells that have nuclei at different heights, giving appearance of two or more layers

Each columnar cell has 200 to 250 cilia on its surface


Goblet cells and submucosal glands are interspersed.

Mucus resides as two layers:

Cilia reside in sol layer; contains thin, watery fluid that allows them to beat freely

Top layer is gel layer that is more viscous and sticky, trapping small particles


Cilia act as tiny "oars" resting in

watery sol layer and beat 1,000 to 1,500 times per minute and propel gel layer and its trapped debris

onward and upward about one inch per minute to

be expelled


In nose, debris-laden secretions pushed toward front of nasal cavity to be expelled through nose

Pseudostratified ciliated columnar epithelium propels gel layer toward oral cavity to be expectorated with cough or swallowed into stomach

The SinusesThe Sinuses

Skull contains air-filled cavities called sinuses that connect to nasal cavity via small passageways

Located around nose and sometimes referred to as paranasal sinuses

Cavities help prolong and intensify sound produced with our voice and helps to lighten weight of head

The SinusesThe Sinuses

Three different sinuses: Frontal, Ethmoid and Maxillary

Sinuses do not exist at birth

Develop as we grow; facial features changes influenced by sinuses as we mature

Sinuses also help to warm and moisturize air

Pharynx: Three PartsPharynx: Three Parts

Pharynx, or throat, is hollow muscular structure beginning behind nasal cavity, lined with epithelial tissue

Pharynx can be divided into three sections

Nasopharynx

Oropharynx

Laryngopharynx

Figure 13-7Figure 13-7The nasopharynx, oropharynx, and The nasopharynx, oropharynx, and

laryngopharynx and related laryngopharynx and related structuresstructures

First Part: First Part: NasopharynxNasopharynx

Nasopharynx is uppermost section, beginning behind nasal cavity

Section contains lymphatic tissue called adenoids; passageways into middle ear called Eustachian tubes

Air from nasal cavity passes through nasopharynx

Second Part: Second Part: OropharynxOropharynx

Oropharynx is located behind oral, or buccal, cavity

Conducts not only atmospheric gas but also food and liquid

Air breathed through both nose and mouth passes through here, and anything that is swallowed

Second Part: Second Part: OropharynxOropharynx

Tonsils are part of lymph system

Palatine tonsils are located in oropharynx, as are lingual tonsils located at back of tongue

During swallowing, uvula and soft palate move in posterior and superior position to protect nasopharynx and nasal cavity from entry of food or liquid; can be overcome by forceful laughing

Third Part: Third Part: LaryngopharynxLaryngopharynx

Laryngopharynx is lowermost portion of pharynx

Air breathed and/or swallowed passes through laryngopharynx

Swallowed materials pass through esophagus to get to stomach

Air travels through larynx and trachea on its way to lungs

The LarynxThe Larynx

Semi rigid structure composed of cartilage connected by muscles and ligaments that provide movement of vocal cords to control speech

“Adam's apple” (thyroid cartilage) is largest of cartilages found in larynx

The Larynx and The Larynx and GlottisGlottis

Cricoid cartilage lies beneath it, providing structure and support for airways so they do not collapse

Glottis is opening that leads into larynx and eventually lungs

The EpiglottisThe Epiglottis

Leaf-shaped flap like fibrocartilage

Closes over opening to larynx when you swallow; opens up when you breathe, as part of swallowing reflex (glottic or sphincter mechanism)

Seals so food does not enter lungs

Figure 13-8The upper airway and related

infections

Vocal Cords as Vocal Cords as Dividing LineDividing Line

Vocal cords act as dividing line between upper and lower airways

Lower airway starts below vocal cords

Upper airway ends at vocal cords

Respiratory DiseasesRespiratory Diseases

Complete the RespiratoryDiseases Worksheet

Due Thursday Nov 12, 2013

Also due: Take home quiz on Anatomy of the Heart

The Lower Respiratory The Lower Respiratory TractTract

Resembles upside-down tree, sometimes called tracheobronchial tree

From vocal cords, air enters trachea, or windpipe, 4½˝ long tube lined with ciliated mucous membrane

The Trachea and EsophagusThe Trachea and Esophagus

C-shaped cartilage found in anterior portion of trachea provide rigidity and protection for exposed airway in neck

Esophagus lies in area where C opens up posteriorly; room for esophagus to expand when you swallow larger chunks of food

Trachea and Mainstem Trachea and Mainstem BronchiBronchi

Trachea is largest pipe; can be thought of as trunk of tree

Trachea begins branching (bifurcating) at center of chest into left and right mainstem bronchi (bronchus is singular form)

Trachea and Mainstem Trachea and Mainstem BronchiBronchi

Site of bifurcation is called carina

Next bronchi must branch into five lobular bronchi; correspond to five lobes of lungs

carina

Bronchi of the Bronchi of the LungLung

Each lung lobe further divided into specific segments; next branching of bronchi called segmental bronchi

At point from trachea down to segmental bronchi, tissue layers of bronchi are all the same, only smaller, as they branch downward

Figure 13-10Three Tissue layers in the

bronchi

• Epithelial layer contains mucociliary escalator

• Middle is lamina propria layer which contains smooth muscle, lymph, and nerve tracts

• Third layer is protective and supportive cartilaginous layer

Bronchi in Lung SegmentsBronchi in Lung Segments

Branching continues to tiny subsegmental bronchi that branch deep within each lung segment

Cartilaginous rings become more irregular and eventually fade away

Closer to gas exchange regions, airways simplify to make it easier for gas molecules to pass through

Bronchi Lead to Bronchi Lead to BronchiolesBronchioles

Bronchioles average 1 mm in diameter

Cilia, goblet cells, and submucosal glands are almost all gone

There is no gas exchange yet

Terminal BronchiolesTerminal Bronchioles

Terminal bronchioles mark border between conducting and respiratory zones

Respiratory BronchioleRespiratory Bronchiole

Next airways beyond terminal bronchioles are respiratory bronchioles, because some gas exchange occurs here

Alveolar Ducts to Alveolar Ducts to AlveoliAlveoli

Alveolar ducts originate from respiratory bronchioles,

These give way to alveoli

Figure 13-11Conduction and gas exchange structures and functions

Alveoli and Pulmonary Alveoli and Pulmonary CapillariesCapillaries

Alveoli are terminal air sacs, surrounded by numerous pulmonary capillaries

Together capillaries and alveoli make up functional unit of lung known as alveolar capillary membrane

Adults have 300–600 million alveoli, with total of 80 square meters (m2) surface area for oxygen molecule to diffuse across into capillaries

Pulmonary CirculationPulmonary Circulation

Blood from right heart entering pulmonary capillaries is high in carbon dioxide and low in oxygen

Gas Exchange at Alveolar Gas Exchange at Alveolar Capillary MembraneCapillary Membrane

http://www.youtube.com/watch?v=AyUtdqiOgCA

Gas exchange takes place and

pulmonary capillary

increases in oxygen

concentration before traveling to left heart to be pumped around

to tissues


1. The pressure of oxygen in the alveolus is higher than in the capillary and by SIMPLE DIFFUSION, the oxygen enters the circulatory

system


2. The pressure of carbon dioxide in the capillary is higher than in the alveolus and

by SIMPLE DIFFUSION, the CO2 enters the respiratory system and is exhaled

Gas Exchange at Cellular Gas Exchange at Cellular MembraneMembrane

3.At the tissue level, the pressure of oxygen in the capillary is higher than in the tissue and by SIMPLE DIFFUSION, the

oxygen enters the cell.

Gas Exchange at Cellular Gas Exchange at Cellular MembraneMembrane

4.The pressure of carbon dioxide in the cell is higher than in the venule and by SIMPLE DIFFUSION, the carbon dioxide enters the

circulatory system

Housing of the LungsHousing of the Lungsand Related Structuresand Related Structures

Lungs reside in thoracic cavity and are separated by region called mediastinum, which contains esophagus, heart, great vessels, and trachea

Breathing in and out causes lungs to move within thoracic cavity

Pleura of the LungsPleura of the Lungs

To prevent irritation of lungs moving against thorax, each lung wrapped in sac or serous membrane called visceral pleura

Pleura of the LungsPleura of the Lungs

Thoracic cavity and upper side of diaphragm lined with continuation of membrane called parietal pleura

Pleural Space with Pleural Space with FluidFluid

Between these two pleural layers is pleural space (intrapleural space), which contains slippery liquid called pleural fluid that reduces friction as individual breathes

The LungsThe Lungs Conical-shaped with rounded peaks (apex) extending 1 to 2 inches above clavicle

Base of lungs rest on right and left hemi diaphragm with right lung base a bit higher to accommodate liver

Cardiac impression

Medial surface of lung has deep, concave cavity that holds heart, called cardiac impression, and is deeper on left side

Hilum of The LungsHilum of The Lungs

Hilum is area where root of each lung is attached, containing main stem bronchus, pulmonary artery and vein, nerve tracts, and lymph vessels

The Lobes of the LungsThe Lobes of the Lungs

Right lung has three lobes: upper, middle, lower lobes; divided by horizontal and oblique fissures

Left lung has one fissure, oblique fissure, and therefore has only two lobes: upper and lower lobes

Lingula is area of left lung that corresponds with right middle lobe

The Lobes of the LungsThe Lobes of the Lungs

Left lung has only two lobes because largest part of heart is located in left lung area

Right lung is larger, with 60% of gas exchange occurring here

Figure 13-15Structures of the thoracic

cavity

The Protective Bony The Protective Bony ThoraxThorax

Bony and cartilaginous frame providing freedom of movement

Protects organs of chest

Includes rib cage, sternum, and thoracic vertebrae to which each rib attaches

Sternum, or breastbone, is centrally located; comprised of manubrium, body, and xiphoid process

The Protective Bony The Protective Bony ThoraxThorax

True ribs (pairs 1–7): called vertebro sternal; connect to sternum and vertebrae

Pairs 8–10: called false ribs or vertebro costal; connect to costal cartilage of superior rib and to thoracic vertebrae

Figure 13-17The thoracic cage

How We BreatheHow We Breathe

Respiratory control center is in medulla oblongata

which is part of the brain stem and is continuous with the

spinal cord

How We BreatheHow We BreatheInspiration: active process

in which diaphragm is

sent signal via phrenic nerve, causing it to contract and

flatten downward, increasing

thoracic cavity space


Increase in thoracic cavity

volume decreases pressure,

creating lower pressure in lungs than outside,

allowing air to rush into lungs

Figure 13-18Figure 13-18How we breatheHow we breathe

Ease of ventilation is called compliance

•High compliance: little effort required to expand lungs•Low compliance: more difficult to expand lungs


Exhalation: passive act;

diaphragm relaxes, which decreases

amount of space in thoracic cavity; pressure in lungs becomes greater than atmospheric pressure; air is pushed out of

lungs


While we can consciously influence

breathing rate,

Our breathing rate is normally controlled by level of carbon dioxide in blood


If carbon dioxide levels rise, it means that not enough CO2 is being ventilated

When this occurs, chemoreceptors in medulla oblongata send signals to respiratory muscles to increase rate and depth of breathing

Factors Affecting Breathing Factors Affecting Breathing RateRate

How We BreatheHow We Breathe Accessory Muscles include:

Scalene muscles in neck

Sternocleido mastoid

Pectoralis major

Pectoralis minor

Figure 13-19Figure 13-19The accessory muscles of The accessory muscles of

exhalationexhalation

Accessory muscles of exhalation assist in more forceful and active exhalation by increasing

abdominal pressure


Main accessory muscles of

exhalation are abdominal muscles

that push up diaphragm or the back muscles that

pull down and compress thoracic

cage

EmphysemaEmphysemaAffects lung compliance:

Bronchioles become damaged and wider, allowing air into lungs, increasing compliance but making it much more difficult to breathe out Breathing then requires the use of more accessory muscles

Damage to the LungsDamage to the Lungs

Figure 13-14Figure 13-14Asthma and emphysemaAsthma and emphysema

Figure 13-20Figure 13-20Classes of drugs used to Classes of drugs used to

treat respiratory disorderstreat respiratory disorders

GAS EXCHANGEGAS EXCHANGE

Complete the GAS EXCHANGE

WORKSHEET IN CLASS

Use a RED pencil to represent the direction of

the oxygen movement and BLUE for the direction of

the carbon dioxide movement

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Survey of Anatomy & Physiology Chap 13

Health & Medicine