UNIT 5 Respiratory Systems Bio2T10

8/6/2019 UNIT 5 Respiratory Systems Bio2T10

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` Sequence of events that results in gas exchange.

` In terrestrial vertebrates it includes 3 steps:

1. Ventilation: Inspiration and

expiration.

2. External respiration: Gas exchange

between air (in lungs) and blood.

Blood then transport Oxygen to the

body tissue cells.

3. Internal respiration: Gas exchange

between blood and tissue fluid.

Blood then transports carbon

dioxide to the lungs.


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External

respiration

Internal

respination

oxygenCarbon dioxide

oxygen Carbon dioxide

Alveoli filled with air (gas)

Body cells surrounded by tissue fluid

Blood part of

circulatory system

contain red pigment

hemoglobin, totransport gasses

Gas exhange surface

must be:

Moist

Thin

Large in relation of

size of body

Process: Diffusion ofgasses (oxygen and

carbon dioxide


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` Is the process whereby an organism uses oxygen

and food to produce energy (ATP) and 2 by

products e.g. water and carbon dioxide

` Glucose + O2 ATP + H2O + CO2

Therefore gaseous exchange is necessary for to get

oxygen for cellular respiration.


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` Consists of:

1. Nose

2. Air passages:

Pharynx Trachea

Bronchus

Bronchioles

3. Lungs Alveoli


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` Nose has a nasal cavity thatleads to the pharynx.

` Nasal cavity is lined with ciliaand hairs and goblet cells thatmake mucus (anti-septic andmoisten air) filter the air dust, pollen and other foreign

material sticks to it.` 3 x turbinate bones divide the

nasal cavity into 4 passages This enlarges the surface ofthe nasal cavity For warming,

cleaning and moisten of air.` Several surface blood vessels

help to warm air.


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` Pharynx pass air form

nose to trachea vialarynx.

` Trachea: long, straight

tube kept open by C-

shaped cartilage rings.` Trachea lined with

cilia and goblet cells

(mucus production)

traps foreign particles


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CILIA (SEM) TRACHEAL LINING


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` Trachea divides in aright and left bronchus consist ofC-shapedcartilage rings and

lined with goblet cells(mucus)` Bronchi branch in lung

to form bronchiolesbranch further andcartilage ringsdisappears lead air toair sacs of lung.

Bronchiole

Left bronchus long,

branch in 2

Right bronchus-short

Branch in 3


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` Right lung (3 lobes -

shorter) and left lung (2

lobes longer, narrow)

` Spongy, elastic pink organ.

` Consists of several air sacs

called alveoli.

` Alveoli are groupedtogether and form the

endings of the bronchioles.


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` Lined with single layer

squamous epithelial cells Thin easy diffusion of gas.

` Alveoli is surrounded by a

network ofblood capillaries

gasses diffuse into and out of

blood.

` Alveoli is lined with moist layer

oxygen dissolves in

moisture and diffuses through

alveoli wall into blood

capillary.


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SEM TEM

Alveoli

Pulmonary artery

(Deoxygenated

blood)

Pulmonary vein

(Oxygenated

blood)

Diaphragm

Bronchiole

Bronchus

Trachea

Pharynx

Turbinate bones


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INSPIRATION

` INSPIRATION

EXPIRATION

` EXPIRATION

Diaphragm

contracts

(moves down)

Diaphragm

relaxes

(moves up)

Rib cage

expands as

rib muscles

contract

Rib cagegets smaller

as rib

muscles

relax

Air inhaledAir exhaled

When pressure in

lungs decrease

air rush in

When pressure in

lungs increase air

is pushed out


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` Air moves in and out of the body via the same

route.

` All terrestrial vertebrates do this except for birds.

` The lungs are not completely emptied during eachbreathing cycle.

` The air entering mixes with used airremaining in

the lungs.

` This help to conserve water, but decreases gas-exchange efficiency


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x A spyrometer can be used to determine how much

air enters the lungs.

x Your lungs has a volume of +/- 5 liters.

x During a normal breath, only 0.5 litersof air is

exchanged This air is known as tidal volume.

x During forced breathing, as much as 3.5 litersof air

can be exchanged, this is known as vital capacity.

(The fitter you are, the higher your vital capacity.)

x +/- 1.5 litersof air always remains in the lungs thisair is known as residual air/volume.


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Brain

Respiratory center

automatically regulates

breathing

Intercostal nerves

stimulate the

intercostal muscles

Intercostal muscles

Pheric nerve stimulates the

diaphragm

Diaphragm


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EXTERNAL RESPIRATION INTERNAL RESPIRATION

` Gas exchange between airin lungs and blood

` Movement driven by

diffusiongradient. ( [] to

[])` Gasses exerts pressure, the

amount of pressure each

gas exerts is called partial

pressure(PO2

and PCO2

)

` Gas exchange betweenblood and tissue fluid

` Movement driven bydiffusiongradient. ( []

to [])` Gasses exerts pressure,the amount of pressureeach gas exerts is called

partial pressure(PO2and P

CO2

)


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` IfPO2 differs across a membrane oxygen will

diffuse from a high to a low pressure.

` IfPCO2 differs across a membrane carbon

dioxide will diffuse from a high to a low pressure.` During inspiration the alveoli fills with air higher

PO2 and lowerPCO2 than blood.

` Oxygen diffuse from alveoli into blood and carbon

dioxide diffuse from blood into alveoli.


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` When blood reaches the tissue, cellular respiration

in cells causes the tissue fluid to have a lowerPO2and a higherPCO2 than the blood.

` Thus oxygen diffuse from a high pressure in theblood to a low pressure in the tissue fluid and

eventually in the tissue cells.

` Carbon dioxide diffuse from a high pressure in the

tissue fluid to a low pressure in the blood.


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` Most oxygen is transported by hemoglobin (red

pigment protein in erythrocytes).

` Oxygen combines with hemoglobin to form

oxyhemoglobin.Hb + O2 = HbO2

Hemoglobin Oxygen Oxyhemoglobin

` A small amount of oxygen is transported in

solution in the blood plasma.


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Each red blood cell carries 250 millionHb molecules = 1 Billion Oxygenmolecules

` Consist of 4 polypeptidechains (protein 2 alphaand 2 beta).

` Each chain is associated

with a heme group.` Each heme group

contains an iron atom.

` Iron binds with oxygen.


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` Most CO2 is transported as bicarbonate ions(HCO3

-)

HOW?

FIRST CO2

binds with water to form carbonic

acid (H2CO3)

CO2+H

2O = H

2CO

3

Then carbonic acid dissosiates to form hydrogenand bicarbonate ions.

H2CO3 = H++HCO3

-


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` A small amountof carbon dioxide is transported

by the Hemoglobin molecules in the form of

carbaminohemoglobin (HbCO2).

CO2 + Hb = HbCO2` The higher the amount of hydrogen ions in the

blood the lower the pH. Therefor hydrogen ions

bond with the globin part of Hb to keep the pH

normal in the blood.


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` The following lower respiratory tract disorders are

caused by exposure to infectious pathogens and /

or polluted air, including tobacco smoke. Pneumonia

Pulmonary Fibrosis

Pulmonary Tuberculosis

Emphysema

Bronchitis

Asthma


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Bacteria streptococcus cancause pneumonia

` Alveoli fill with pus and

fluid making gas

exchange difficult

X-ray of a patient

with pneumonia


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` Caused by a bacillus

bacterium


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` Alveoli burst and fuse

into enlarged air spaces.

Surface area for gas

exchange is reduced.


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` Airways are inflamed due

to infection (acute) or due

to an irritant (Chronic).

Coughing brings up

mucus and pus.


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` Airways are inflamed due

to irritation and

bronchioles constrict due

to muscle spasms


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` Smoking causes almost 90% of all lung cancers

and is also a major cause of emphysema.

Healthy normallung of a non-

smoker

Lung of a smoker


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Lung with large

tumors causing lung

cancer

UNIT 5 Respiratory Systems Bio2T10

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