10. unit 2 respiratory system

8/3/2019 10. Unit 2 Respiratory System

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Unit 2A

Human Form & Function

Body systems

The respiratory system


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Further information

Further information aboutthis topic can be found inOur Human Species

(3rd edtn)

Chapter 11, sections 1-2,4-6


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Background reading

Our Human Species (3rd edtn.)

Chapter 11, Gas Exchange

Sections 1, 2, 4, 5, 6, 7

Student work book

Topic 9, Respiratory system


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Structure


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Organs of the respiratory system

Larynx

TracheaRib cage

Bronchus

Mediastinum

Lung

Diaphragm


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Section through the head

Nasal cavity

Palate

Tongue

Pharynx

Hyoid bone

Epiglottis

Larynx

Esophagus

Teeth

Vocal cords

The Miles Kelly Art library, Wellcome Images


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The mucous lining

The nasal cavity and upper airwayshave amucous lining.

The epithelial lining containsgoblet

cellswhich secrete a clear, stickymucus.

The function of mucus is to trap dirt

particles and microbes before theyenter the lungs.


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The nose (nasal cavity)

Air enters and leaves the bodythrough the nose.

Here it is cleaned, warmed andmoistened before entering thebody.

The nasal secretions contain ananti-bacterial enzymelysozyme.


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A section through the nasal cavity


Nostril

Hard palateSoft palate

Sinus

NASALCAVITY


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The larynx (Adams apple or voice box)

The larynx is a box-likestructure constructedfrom nine cartilagesand is the entrance to

the trachea and lungs. The larynx houses the

vocal folds orvocal

cords. The entrance to thelarynx is protected bytheepiglottis.

Grays Anatomy


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The bronchial tree

Larynx

Trachea

Bronchus

Bronchiole

The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)


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Trachea & bronchi

The trachea & bronchi are

reinforced with C-shaped rings ofcartilage (these prevent the tubescollapsing during inhalation).


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The bronchi


Mucouslining

Muscular

wall

Cartilagerings


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The upper airways are linedwith a ciliated mucous

membraneThe sticky mucus traps dirt &microbes

The cilia sweep the dirty mucusup the trachea and into thethroat.


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The ciliated lining tissue

Mucus-secretinggoblet cells

Cilia

G. Meyer, ANHB-UWA,


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EM of ciliated epithelium & goblet cells

D Gregory & D Marshall, Wellcome Images


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Alveoli

The brochioles terminate in microscopicclusters of air sacs thealveoli.

Gas exchange takes place in the alveoli.

AlveoliG. Meyer, ANHB-UWA


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The alveoli (air sacs)



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Section through a lung showing alveoliand blood supply

M I Walker, Wellcome Images


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Gasexchange


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Exchange surfaces

Like all exchange surfaces, thealveoli:

are very thinhave a large surface area

are moisthave a rich blood supply


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Breathing

Breathing (sometimes referred toasventilation) is the process ofmoving air into and out of thelungs.

The purpose of breathing is to

exchangeoxygenandcarbondioxidebetween the lungs andthe air .


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Boyle's law

Boyle's law states that: for a fixed amountof gas kept at a fixed temperature,pressure (P)and volume (V)are inversely

proportional (while one increases, theother decreases).

This can be stated mathematically as:PV = k

where: Pis thepressure, Vis thevolume&kis a constant value representative ofthe pressure and volume of the system.
http://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Pressure


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Respiration

Respiration is the transport ofoxygen from the air to the

tissues and the transport ofcarbon dioxide in the oppositedirection.

[not to be confused with the process ofcellular respiration discussed earlier]


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External respiration andInternal respiration

External respirationis themovement of O

2

and CO2

betweenthe lungs and the bloodstream.

Internal respirationis the

exchange of O2 and CO2 betweenthe blood and the tissues.


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External respiration

Partial pressure (mmHg)

Alveolar air Deoxygenatedblood

Oxygenatedblood

Oxygen 100 40 100

Carbon

Dioxide

40 44 40

Breathing maintains the correct

concentration of gases in the lungs

Concentration

gradient


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Breathing inhaling(remember P1V1 = P2V2)

Anatomicalchanges

V P1 P1:P2 Result

Rib cageraised

Diaphragm

flattens

Increases Decreases P1


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Thoracic volume

Rib cage relaxesDiaphragm domed

Rib cage raisedDiaphragm flattens


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P1V1 = P2V2

A bicycle pump worksin much the same way

as the lungs


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The lungs work in much the sameway as a bicycle pump

If you increase the volume of thechamber air is sucked in

If you decrease the volume of thechamber air is forced out


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Breathing exhaling(remember P1V1 = P2V2)

Anatomicalchanges

V P1 P1:P2 Result

Rib cagerelaxes

Diaphragmdomed

Decreases Increases P1>P2 Air forcedout oflungs

V = volume of thoracic cavity

P1 = pressure in thoracic cavity

P2 = air pressure


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INHALE EXHALE

Ribcageraised

Ribcagelowered

Diaphragm

domed

Diaphragmflattened

Thoracic volume

increasedThoracic pressure< air pressure

Thoracic volume

decreasedThoracic pressure> air pressure


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Why breathe?

Fresh air passingthrough the lungsdelivers oxygen to thered blood cells. At the

same time, wastecarbon dioxide isremoved from theblood.This can only occur iffresh air is constantlycirculating through thelungs.

Wellcome Photo Library

Carbondioxide

Oxygen


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Oxygen transport

Oxygen combines withhaemoglobininRBCs to formoxyhaemoglobin.


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Carbon dioxide transport

Most CO2 is transported in the plasmaas dissolvedbicarbonate ions.-


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Oxygen saturation
http://pharyngula.org/~pzmyers/MyersLab/teaching/Bi104/l07/bohr.html


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Diseased lung tissue

Photo by Pll

CDC

A. healthy lung tissue

B. Smokers lung

C. Emphysema

A

B

C


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Study Guide

Read:

Our Human Species

Chapter 11, sections 1-2, 4-6

Complete:

Workbook

Topic 9, Respiratory system

10. unit 2 respiratory system

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