Respiratory System Biol 105 Lecture 18 Chapter 14

Respiratory System

Biol 105

Lecture 18

Chapter 14

Copyright © 2009 Pearson Education, Inc.

Outline - Respiratory System

I. Function of the respiratory system

II. Parts of the respiratory system

III. Mechanics of breathing

IV. Regulation of breathing


Respiratory system Function

The function of the respiratory system is to bring in oxygen to the body and remove carbon dioxide.


The Respiratory System

Figure 14.1

Breathing moves airin and out of the lungs.

External respirationis the exchange ofoxygen and carbondioxide between thelungs and the blood.

Internal respiration isthe exchange of oxygenand carbon dioxidebetween blood and thebody tissues.

Gas transportmoves oxygen andcarbon dioxidebetween the lungsand the body tissues.

TissueGas diffusion Gas diffusion

Oxygentransport

Carbondioxide

transportLungs


This type of tissue covers and lines body parts

1. Connective

2. Epithelial

3. Muscle

4. Nervous

Connective

Epithelia

l

Muscl

e

Nervous

25% 25%25%25%


Lined by pseudostratified ciliated columnar epithelial cells. The cilia sweeps mucus, germs and debris toward the throat.

Mucus produced by goblet cells.

Smoking damages the ciliated cells

8-4

Cells lining respiratory tract



Figure 14.4a


Ciliated cells in respiratory tract



Figure 14.3



Figure 14.2 (1 of 2)

Nasal cavity• Produces mucus• Filters, warms, andmoistens air• Olfaction

Pharynx• Passageway forair and food

Sinuses• Cavities in skull• Lighten head• Warm and moistenair

Intercostalmuscles Diaphragm

• Muscle sheet betweenchest and abdominalcavities with a role inbreathing

UPPER RESPIRATORYSYSTEM

RESPIRATORYMUSCLES • Cause breathing

• Filters, warms, andmoistens air

• Move ribs during breathing



Figure 14.2 (2 of 2)

Epiglottis• Covers larynx duringswallowing

Bronchi• Two branches oftrachea that conductair from trachea toeach lung

Bronchioles• Narrow passagewaysto conduct air frombronchi to alveoli

Lungs• Structures that containalveoli and airpassageways• Allow exchange ofoxygen and carbondioxide betweenatmosphere and blood

Alveoli• Microscopic chambersfor gas exchange

Trachea• Connects larynx withbronchi leading toeach lung• Conducts air to andfrom bronchi

Larynx• Air passageway• Prevents food and drinkfrom entering lowerrespiratory system• Produces voice

LOWER RESPIRATORYSYSTEM• Exchanges gases


Functions:

1. filters the air

2. warms the air

3. moisten the air entering the lungs

4. smell (which also plays a role in the sense of taste)

8-3

1. Nasal cavity


Parts of the nasal cavity:

Mucus membranes - secrete sticky mucus to trap germs & debris.

Contains olfactory receptor cells for the sense of smell

Sinuses – air filled cavities, warm and moisten air

8-3

1. Nasal cavity


Functions - is a passageway for air, liquids, and food. (swallowing begins here). Connects the nasal cavity to the esophagus and the larynx

Tonsils are found here – lymphatic tissue that protects against infection

8-4

2. Pharynx


Functions

1. Connects the pharynx to the trachea

2. Contains vocal cords used to generate sound

3. Prevents food from entering lower respiratory tract

8-4

3. Larynx


Structure made from cartilage

Epiglottis closes the trachea when swallowing

8-4

3. Larynx




Windpipe held open by concentric rings of cartilage

Function – Connects the larynx to the bronchi.

8-4

4. Trachea


Trachea leads to the bronchial tree:

5. Bronchi (bronchus)

6. Bronchioles

7. Alveoli (alveolus)

8-4

Bronchial Tree



Figure 14.7


Sacs at the end of the bronchioles, they are surrounded by blood capillaries .

Function: It is here that the oxygen diffuses across the membrane into the capillaries, and carbon dioxide goes from the capillaries to the inside of the lungs.

8-6

7. Alveoli


Alveoli

Lungs - have about 300 million alveoli

The structure of the alveoli increases surface area of lung

For alveoli to function properly they are coated with phospholipid molecules called surfactant that keep them open


Alveoli

Figure 14.8



Table 14.1 (1 of 2)



Table 14.1 (2 of 2)


What cells secrete mucus

1. cilliated columnar epi

2. goblet

3. squamous epi

4. osteocytes

Cilliate

d columnar e

pi

goblet

Squamous epi

osteocy

tes

25% 25%25%25%


The tube connecting the larynx to the primary bronchi is

1. pharynx

2. trachea

3. bronchioles

4. alveoli

pharynx

trach

ea

bronch

ioles

alveoli

25% 25%25%25%


Common passageway for air, food and drink

1. pharynx

2. trachea

3. bronchioles

4. alveoli

pharynx

trach

ea

bronch

ioles

alveoli

25% 25%25%25%


Conducts air from the trachea to the bronchioles

1. pharynx

2. trachea

3. bronchus

4. alveolus

pharynx

trach

ea

bronch

i

alveoli

25% 25%25%25%


Gas exchange takes place here

1. pharynx

2. trachea

3. bronchioles

4. alveoli

pharynx

trach

ea

bronch

ioles

alveoli

25% 25%25%25%


Which cavity is the lung located in?

1. abdominal

2. pericardial

3. pleural

4. dorsal

Abdominal

Pericard

ial

Pleural

Dorsal

25% 25%25%25%


Inhalation

Figure 14.9a

The lungs expand, andair moves in.

The chest cavity increasesin size, and pressure withinthe lungs decreases.

Diaphragmcontracts

and flattens Diaphragmcontracts

Intercostalmusclescontract

Rib cagemoves up

and out

Air flow

Inhalation

(a)


Inhalation

When the diaphragm and intercostal muscles contract, the volume of the thoracic cavity increases, causing the pressure in the lungs to decrease

Inhalation is also called inspiration


Exhalation

Figure 14.9b

The lungs recoil,and air moves out.

The chest cavity decreasesin size, and pressurewithin the lungs increases.

Diaphragmrelaxes and

moves upward Diaphragmrelaxes

Intercostalmuscles relax

Rib cagemoves down

and inward

Air flow

Exhalation

(b)


Exhalation

Exhalation = Expiration

When the same muscles relax, volume of the thoracic cavity decreases, pressure in the lungs increase


Air Volumes

The volume of air inhaled or exhaled during a normal breath is called the tidal volume

Tidal volume is usually around 500 ml

The volume of air moved into and out of the lungs is an indication of health


Air Volumes

Inspiratory reserve volume = forced inhalation volume

Expiratory reserve volume = forced exhalation volume

Residual volume is the amount of air left in the lungs after forced exhalation

Vital capacity is the amount of air brought in and out of the lungs during forced breathing


Air Volumes

Figure 14.10 (1 of 2)

6000

5000

4000

3000

2000

1000

0

Inspiratoryreserve(forced

inhalation)volume

Vitalcapacity

Expiratory reserve(forced exhalation)

volume

Residualvolume

Tidal volume

Totallung

capacity

Lu

ng

Volu

me (

ml)


Remember that O2 enters and CO2 leaves the lungs = External respiration

Then O2 and CO2 is exchanged between the blood vessels and tissues = Internal Respiration

This gas exchange is due to diffusion

8-14

Gas Exchanges in the Body


Oxygen is transported on Hemoglobin.

When Oxygen is bound to hemoglobin, then it is called Oxyhemoglobin

8-15

Oxygen Transport


1. CO2 is transported dissolved in the plasma (10%)

2. CO2 is bound to hemoglobin (20%)

3. CO2 is converted to bicarbonate ions (70%)

8-14

Carbon Dioxide Transport


CO2 + H2O H2CO3 H+ + HCO3-

8-14

Bicarbonate ions

Carbonic anhydrase


Diffusion of Gasses: Alveoli and Capillaries

Figure 14.11 (2 of 2)


Diffusion of Gasses: Capillaries and Tissues

Figure 14.11 (1 of 2)


Normally we breath 12 - 15 ventilations per minute.

This rate is controlled by the medulla oblongata region of the brain. Nerves transmit signal to the diaphragm and muscles.

Chemoreceptors in the medulla oblongata and arteries detect levels of CO2 and O2 in the blood, controlling the rate and depth of breathing.

8-12

Regulation of Breathing


Important Concepts

Read Ch 15

What is the function of the respiratory system?

What is the location and function of the all the parts of the respiratory system?

What are the parts of the nasal cavity and their functions?

What are the parts of the larynx and their functions?


Important Concepts

What cell types lines the trachea, what are their functions, be able to discus how smoking effects this tissue?

Where does the exchange of gases occur in the lungs?

What cavity contains the lungs?

What controls the rate of breathing?

Be able to discuss the mechanics of breathing?


Important Concepts

How is oxygen carried in the blood?

How is carbon dioxide carried in the blood, know all the ways, and the which is the predominate mode? (You don’t need to know the chemical equation of bicarbonate formation)

What is the diaphragm and what is its function?


Definitions

Goblet cells, sinuses, epiglottis, surfactant, diaphragm, intercostal muscles, Inhalation/inspiration, exhalation/expiration tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume, vital capacity, hemoglobin, oxyhemoglobin, chemoreceptors

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Respiratory System Biol 105 Lecture 18 Chapter 14