9. Sistem Respirasi

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9

Respiratory System


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Respiration

Ventilation: Movement of air into and

out of lungs

External respiration: Gas exchangebetween air in lungs and blood

Transport of oxygen and carbon dioxide

in the blood Internal respiration: Gas exchange

between the blood and tissues


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Respiratory System Functions

Gas exchange: Oxygen enters blood andcarbon dioxide leaves

Regulation of blood pH: Altered by changing

blood carbon dioxide levels

Voice production: Movement of air past vocal

folds makes sound and speech

Olfaction: Smell occurs when airborne

molecules drawn into nasal cavity Protection: Against microorganisms by

preventing entry and removing them


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Respiratory System Divisions

Upper tract

Nose, pharynx

and associated

structures Lower tract

Larynx, trachea,

bronchi, lungs


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Nasal Cavity and Pharynx


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Nose and Pharynx

Nose

External nose

Nasal cavity

Functions

Passageway for air

Cleans the air

Humidifies, warms

air Smell

Along with

paranasal sinuses

are resonating

chambers forspeech

Pharynx

Common opening for

digestive and

respiratory systems Three regions

Nasopharynx

Oropharynx

Laryngopharynx


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Larynx

Functions Maintain an open passageway for air movement

Epiglottis and vestibular folds prevent swallowed materialfrom moving into larynx

Vocal folds are primary source of sound production


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Vocal Folds


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Trachea

Windpipe Divides to

form

Primary

bronchi

Carina:

Cough

reflex


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Tracheobronchial Tree

Conducting zone

Trachea to terminal bronchioles which is

ciliated for removal of debris

Passageway for air movement Cartilage holds tube system open and

smooth muscle controls tube diameter

Respiratory zone Respiratory bronchioles to alveoli

Site for gas exchange


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Tracheobronchial Tree


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Bronchioles and Alveoli


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Alveolus and Respiratory

Membrane


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Fig. 4. Effects of methacholine ondepth of airway

surface liquid. a: control tissuenot exposed to methacholine.

b: 2-min methacholine exposure.Putative

sol and mucous gel are clearlyvisible. c: 30-min

exposure. Tissues were radiantetched for 20 s to 1

min. Scale bar 5 20 m.

FromAm. J. Physiol. 274 (LungCell. Mol. Physiol. 18): L388L395, 1998.


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Lungs

Two lungs: Principal organs of respiration Right lung: Three lobes

Left lung: Two lobes

Divisions

Lobes, bronchopulmonary segments, lobules


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Thoracic Walls

Muscles of Respiration


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Thoracic Volume


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Pleura

Pleural fluid produced by pleural membranes Acts as lubricant

Helps hold parietal and visceral pleural

membranes together


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Ventilation

Movement of air into and out of lungs

Air moves from area of higher pressure to

area of lower pressure

Pressure is inversely related to volume


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Alveolar Pressure Changes


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Changing Alveolar Volume

Lung recoil Causes alveoli to collapse resulting from

Elastic recoil and surface tension

Surfactant: Reduces tendency of lungs to collapse

Pleural pressure

Negative pressure can cause alveoli to

expand

Pneumothorax is an opening between

pleural cavity and air that causes a loss of

pleural pressure


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Normal Breathing Cycle


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Compliance

Measure of the ease with which lungs

and thorax expand

The greater the compliance, the easier it is

for a change in pressure to causeexpansion

A lower-than-normal compliance means

the lungs and thorax are harder to expand Conditions that decrease compliance

Pulmonary fibrosis

Pulmonary edema

Respiratory distress syndrome


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Pulmonary Volumes

Tidal volume Volume of air inspired or expired during a normal inspirationor expiration

Inspiratory reserve volume Amount of air inspired forcefully after inspiration of normal

tidal volume

Expiratory reserve volume Amount of air forcefully expired after expiration of normal

tidal volume

Residual volume Volume of air remaining in respiratory passages and lungs

after the most forceful expiration


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Pulmonary Capacities

Inspiratory capacity Tidal volume plus inspiratory reserve volume

Functional residual capacity Expiratory reserve volume plus the residual volume

Vital capacity Sum of inspiratory reserve volume, tidal volume, and

expiratory reserve volume

Total lung capacity Sum of inspiratory and expiratory reserve volumes plus the

tidal volume and residual volume

S i t d L


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Spirometer and Lung

Volumes/Capacities

Mi t d Al l


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Minute and Alveolar

Ventilation

Minute ventilation: Total amount of airmoved into and out of respiratory systemper minute

Respiratory rate or frequency: Number ofbreaths taken per minute

Anatomic dead space: Part of respiratorysystem where gas exchange does not take

place Alveolar ventilation: How much air per

minute enters the parts of the respiratory

system in which gas exchange takes place


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Ph i l P i i l f G


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Physical Principles of Gas

Exchange

Partial pressure The pressure exerted by each type of gas in a

mixture

Daltons law Water vapor pressure

Diffusion of gases through liquids

Concentration of a gas in a liquid is determined byits partial pressure and its solubility coefficient

Henrys law


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Exchange

Diffusion of gases through therespiratory membrane Depends on membranes thickness, the diffusion

coefficient of gas, surface areas of membrane, partial

pressure of gases in alveoli and blood

Relationship between ventilation andpulmonary capillary flow Increased ventilation or increased pulmonary capillary

blood flow increases gas exchange Physiologic shunt is deoxygenated blood returning

from lungs

O d C b Di id


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Oxygen and Carbon Dioxide

Diffusion Gradients

Oxygen Moves from alveoli into

blood. Blood is almost

completely saturated

with oxygen when itleaves the capillary

P02in blood decreases

because of mixing with

deoxygenated blood

Oxygen moves from

tissue capillaries into

the tissues

Carbon dioxide

Moves from tissues

into tissue capillaries

Moves from

pulmonary capillaries

into the alveoli


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Changes in Partial Pressures

Hemoglobin and Oxygen


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Transport

Oxygen is transported by hemoglobin(98.5%) and is dissolved in plasma (1.5%)

Oxygen-hemoglobin dissociation curve shows

that hemoglobin is almost completely

saturated when P02is 80 mm Hg or above.

At lower partial pressures, the hemoglobin

releases oxygen.

A shift of the curve to the left because of anincrease in pH, a decrease in carbon dioxide,

or a decrease in temperature results in an

increase in the ability of hemoglobin to hold

oxygen



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Transport

A shift of the curve to the right because of a

decrease in pH, an increase in carbon dioxide,

or an increase in temperature results in a

decrease in the ability of hemoglobin to holdoxygen

The substance 2.3-bisphosphoglycerate

increases the ability of hemoglobin to release

oxygen

Fetal hemoglobin has a higher affinity for oxygen

than does maternal

Oxygen Hemoglobin


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Oxygen-Hemoglobin

Dissociation Curve at Rest


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Bohr effect:


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Temperature effects:


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Shifting the Curve


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Transport of Carbon Dioxide

Carbon dioxide is transported as bicarbonateions (70%) in combination with blood proteins

(23%) and in solution with plasma (7%)

Hemoglobin that has released oxygen binds

more readily to carbon dioxide than

hemoglobin that has oxygen bound to it

(Haldane effect)

In tissue capillaries, carbon dioxide combineswith water inside RBCs to form carbonic acid

which dissociates to form bicarbonate ions

and hydrogen ions


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Transport of Carbon Dioxide

In lung capillaries, bicarbonate ions andhydrogen ions move into RBCs and chloride

ions move out. Bicarbonate ions combine

with hydrogen ions to form carbonic acid.

The carbonic acid is converted to carbon

dioxide and water. The carbon dioxide

diffuses out of the RBCs.

Increased plasma carbon dioxide lowersblood pH. The respiratory system regulates

blood pH by regulating plasma carbon dioxide

levels

CO Transport and Cl- Movement


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CO2Transport and Cl-Movement


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Ventilation-perfusion coupling:

Respiratory Areas in


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Respiratory Areas in

Brainstem

Medullary respiratory center

Dorsal groups stimulate the diaphragm

Ventral groups stimulate the intercostal and

abdominal muscles

Pontine (pneumotaxic) respiratory group

Involved with switching between inspiration

and expiration


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Respiratory Structures in Brainstem


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Rhythmic Ventilation

Starting inspiration Medullary respiratory center neurons are continuously active Center receives stimulation from receptors and simulation from

parts of brain concerned with voluntary respiratory movementsand emotion

Combined input from all sources causes action potentials tostimulate respiratory muscles

Increasing inspiration More and more neurons are activated

Stopping inspiration Neurons stimulating also responsible for stopping inspiration and

receive input from pontine group and stretch receptors in lungs.Inhibitory neurons activated and relaxation of respiratory musclesresults in expiration.


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M difi ti f V til ti


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Modification of Ventilation

Cerebral and limbic

system

Respiration can be

voluntarily controlled

and modified by

emotions

Chemical control Carbon dioxide is

major regulator

Increase or decrease in

pH can stimulatechemo- sensitive area,

causing a greater rate

and depth of respiration

Oxygen levels in blood

affect respiration whena 50%or greater

decrease from normal

levels exists

M dif i R i ti


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Modifying Respiration

Regulation of Blood pH and


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Regulation of Blood pH and

Gases

H i B R fl


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Herring-Breuer Reflex

Limits the degree of inspiration and

prevents overinflation of the lungs

Infants

Reflex plays a role in regulating basic rhythm ofbreathing and preventing overinflation of lungs

Adults

Reflex important only when tidal volume large as in

exercise


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Ventilation in Exercise

Ventilation increases abruptlyAt onset of exercise Movement of limbs has strong influence

Learned component

Ventilation increases gradually

After immediate increase, gradual increaseoccurs (4-6 minutes)

Anaerobic threshold is highest level ofexercise without causing significant changein blood pH If exceeded, lactic acid produced by skeletal

muscles

Eff t f A i


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Effects of Aging

Vital capacity and maximum minute

ventilation decrease

Residual volume and dead space

increase

Ability to remove mucus from

respiratory passageways decreases

Gas exchange across respiratory

membrane is reduced


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19

U

nitFive

Holes

Human Anatomy & Physiology

Eighth Edition

Chapter 19

Respiratory System

I Introduction


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I. Introduction

(p. 739)

A. The respiratory system consists of a group of

passageways that filter incoming air and

transport it into the microscopic alveoli where

gases are exchanged.

B. The entire process of exchanges gases between

the atmosphere and body cells is called

respiration and consists of the following;

ventilation, external respiration, transport in the

bloodstream, internal respiration, and cellularrespiration.

II Why We Breathe


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II. Why We Breathe

(p. 739)

A. We, on a macroscopic level, need to breathe

because our cells, on a microscopic level,

require oxygen as a final electron acceptor in the

process of cellular respiration, and must rid

themselves of carbon dioxide as a by-product of

the same metabolic pathways.


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III. Organs of the Respiratory System

(p.740; Fig. 19.1; Table 19.1)A. The organs of the respiratory tract can be

divided into two groups: the upper respiratory

tract (nose, nasal cavity, sinuses, and pharynx),

and the lower respiratory tract (larynx, trachea,

bronchial tree, and lungs).

B. Nose (p. 740)

C. Nasal Cavity (p. 740; Figs. 19.2, 19.3)

D. Sinuses (p. 741; Fig. 19.4)

.System (p 740; Fig 19 1; Table


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System (p.740; Fig. 19.1; Table

19.1)

E. Pharynx (p. 741)

F. Larynx (p. 742; Figs. 19.5-19.7)

G. Trachea (p. 744; Figs. 19.8-19.11)

H. Bronchial Tree (p. 746, Figs. 19.12-19.18)I. Lungs (p. 750; Fig. 19.19)


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IV Breathing Mechanism


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IV. Breathing Mechanism

(p. 751)

A. Ventilation (breathing), the movement of air in

and out of the lungs, is composed on inspiration

and expiration.

B. Inspiration (p. 751; Figs. 19.20-19.23; Table 19.2)

C. Expiration (p. 756; Fig. 19.24; Table 19.3)

D. Respiratory Volumes and Capacities (p. 757; figs.

19.25, 19.26; Table 19.4)

E. Alveolar Ventilation (p. 758)

F. Nonrespiratory Air Movements (p. 759; Table19.5)


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V. Control of Breathing


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V. Control of Breathing

(p. 760)

A. Normal breathing is a rhythmic, involuntary act.

B. Respiratory Center (p. 760; Figs. 19.27, 19.28)

C. Factors Affecting Breathing (p. 762; Figs. 19.29,

19.30; Table 19.6)


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VI. Alveolar Gas Exchanges


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eo a Gas c a ges

(p. 764)

A. The alveoli, located at the end of the bronchial

tree, are the sites of gas exchange between the

atmosphere and the blood.

B. Alveoli (p. 764; Fig. 19.31)

C. Respiratory Membrane (p. 765; Figs. 19.32-19.34)

D. Diffusion through the Respiratory Membrane (p.

765)


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VII. Gas Transport


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p

(p. 767; Table 19.7)

A. Gases are transported in association with

molecules in the blood or dissolved in the

plasma.

B. Oxygen Transport (p. 767; Figs. 19.35-19.39)

C. Carbon Monoxide (p. 769)

D. Carbon Dioxide Transport (p. 769; Figs.

19.40-19.42)


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The End.

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9. Sistem Respirasi