Transcript Chapter 17: Respiratory, Cardiovascular and Excretory Systems

Chapter 17
Clearing the Air
Respiratory, Cardiovascular, and Excretory Systems
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17.1 Effects of Smoke on the Respiratory
System
 ETS – Environmental Tobacco Smoke or
“secondhand smoke” is inhaled by
passive smokers - people who are in the
same environment as active smokers
 Carbon monoxide = most abundant chemical
in ETS
 ETS has a high concentration of particulates
(tar)
 ETS damages lungs, but chemicals can also
pass into bloodstream
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17.1 Effects of Smoke on the Respiratory
System
On average, a resting
human:
 Breathes once every
12 seconds
 Takes a breath with
a volume of about
500 mililiters
 Sends about 6 liters
of air per minute into
the lungs
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17.1 Effects of Smoke on the Respiratory
System - Diaphragm
 Breathing is accomplished by the
diaphragm and rib cage.
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17.1 Effects of Smoke on the Respiratory
System - Lungs
 Respiratory tree starts
with the trachea
 Air enters the lungs
through bronchi.
 Bronchi branch into
bronchioles.
 Bronchioles finally end at
alveoli
 small, vascularized sacs
 Site of gas exchange
with blood
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17.1 Effects of Smoke on the Respiratory
System - Lungs
 On average, lungs contain about 300
million alveoli, and these contain the
respiratory surface through which the body
acquires oxygen and eliminates CO2
waste.
 The total area
of the respiratory
surface in a pair
of lungs is about
the same area
as a tennis court.
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Figure 17.3
17.1 Effects of Smoke on the Respiratory
System - Lungs
 Each alveolus is surrounded by a network
of capillaries—tiny, thin-walled blood
vessels
(a)
(b)
Blood in:
Low oxygen,
high carbon dioxide
Air
Blood out:
High oxygen,
Low carbon dioxide
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Figure 17.4
17.1 Effects of Smoke on the Respiratory
System - Gas Exchange
 Gas exchange is the
primary function of the
lungs:
 O2 from the environment
is exchanged for CO2
from the body.
 Gas exchange occurs
by simple diffusion
between the alveoli and
the capillaries.
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Alveolus: oxygen concentration high,
carbon dioxide concentration low
O2
Diffusion
CO2
Capillary: oxygen concentration low,
carbon dioxide concentration high
Figure 17.5
17.1 Effects of Smoke on the Respiratory
System - Gas Exchange
Why is O2 needed and where does CO2 come from?
 Cells use ATP for energy.
 ATP is made during cellular respiration
 The molecular bonds in sugar molecules are
broken to release energy, and the remaining
carbons are given off as CO2
 O2 from the environment serves as the final
electron receptor in cellular respiration, allowing for
the energy from electrons to be used to build ATP.
 For review, see chapter 4
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Figure 17.5
17.1 Effects of Smoke on Respiratory System
The Role of Hemoglobin in Gas Exchange
 CO2 easily diffuses from blood to air
 O2 requires help to enter the blood.
 Hemoglobin – respiratory pigment, a
protein that binds to oxygen
 Hemoglobin turns bright red when it
binds with oxygen
 A single hemoglobin is made up of 4
different protein chains, each with
an iron atom
 A red blood cell contains about 250
million hemoglobin molecules; it can
carry 1 billion oxygen molecules
Protein chains
Oxygen (O2)
Iron (Fe+++)
Heme group
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Figure 17.6
17.1 Effects of Smoke on Respiratory System
The Role of Hemoglobin in Gas Exchange
 Hemoglobin is efficient at binding O2, but even
more effective at binding carbon monoxide.
 Even small amounts of carbon monoxide can tie up
a lot of hemoglobin.
 Carbon monoxide causes oxygen shortages in
tissues.
 Carbon monoxide is especially damaging to fetuses
and embryos.
 Lower than average birth weights associated with
smoking mothers are due to oxygen deprivation.
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17.1 Effects of Smoke on Respiratory System
Smoke Particles and Lung Function
 The majority of the damage to lungs is
caused by particulates (tar) in smoke,
which damage the surfaces of the lungs.
 Children and infants particularly vulnerable
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17.1 Effects of Smoke on Respiratory System
Bronchitis and Asthma
 Particles can interfere with the lung’s defense
systems
 Cough is first response to lung irritants
 Small particles don’t trigger cough; they become
trapped in mucus lining the respiratory tract
 Cilia move trapped particles to nose and mouth –
i.e. mucociliary escalator
 Particulates increase mucus production, but
damage cilia => smokers cough or Bronchitis
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17.1 Effects of Smoke on the Respiratory
System - Smoke Particles and Lung Function
 Bronchitis
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Figure 17.7
17.1 Effects of Smoke on the Respiratory
System - Bronchitis and Asthma
 Asthma = an allergic reaction where
bronchioles constrict and mucus
production increases.
 Particulates are known to exacerbate
asthma.
 The EPA estimates that environmental
tobacco smoke, or ETS, will cause 26,000
additional cases of asthma per year.
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17.1 Effects of Smoke on the Respiratory
System - Bronchitis and Asthma
 Tiniest particles of smoke can even reach
alveoli where gas exchange occurs.
 Without cilia, these particles can remain in
the alveoli for long periods
 Causes irritation or even permanent
damage to alveoli called Emphysema
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17.1 Effects of Smoke on Respiratory System
Emphysema
 As alveoli are damaged, scar tissue forms
and alveoli merge into fewer and larger sacs.
 This drastically reduces surface area for gas
exchange.
 The damage
is permanent;
lung tissue
is not
regenerated.
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Figure 17.8
17.1 Effects of Smoke on Respiratory System
Lung Cancer
Cancerous tumor
 Many of the particulates in
cigarette smoke contain
chemicals known to be
carcinogens
 Particulates can stay on
lung surfaces for long
periods of time
 Risk of mutation remains
long after cigarette has
been smoked
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Figure 17.9
17.1 Effects of Smoke on the Respiratory
System - Lung Cancer
PLAY
Animation—Gas Exchange in the Lung
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17.2 Spreading the Effects of Smoke:
The Cardiovascular System
 Spreads components of tobacco smoke
through body, leading to:
1. Throat, bladder and pancreatic cancer
2. high blood pressure, heart attack, stroke
3. Premature aging of skin
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17.2 Spreading the Effects of Smoke:
The Cardiovascular System
 Three main components
1. Circulating fluid (blood)
2. Pump (heart)
3. Vascular system (blood vessels and capillaries)
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17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood
 The average adult
human has 5 liters
(11 pints) of blood
 Consists of cellular
and liquid components
 Cellular portion =
red blood cells,
white blood cells,
platelets
 Liquid portion =
plasma
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Figure 17.10
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood
 Cellular components of blood are
produced by stem cells in the bone
marrow.
Blood stem
cell
Blood stem cell
Platelet-producing
cell
Red
Platelets
blood cells
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White
blood cells
Figure 17.11
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood
 Red blood cells
White blood
cell
Red blood
cell
 carry oxygen; shape
provides large surface
area to volume ratio
 White blood cells
 several varieties;
components of
immune system
 Platelets
 produce blood clots,
prevent blood loss
Fibrin
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Platelet
Figure 17.12
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood
Tobacco on Blood Clots
 Tobacco smoke
increases stickiness of
platelets and promotes
production of fibrinogen
(precursor of fibrin)
 Thrombosis = when a
blood clot blocks a blood
vessel
 Embolism = when a clot
breaks free and then
blocks a distant vessel
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White blood
cell
Fibrin
Red blood
cell
Platelet
Figure 17.12
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Heart
From
body
Heart Structure
 The heart consists
of four chambers
1. Two atria
2. Two ventricles
Semilunar
valves
To lungs
SA node
Right
atrium
 Pumps blood
through two
parallel systems
1. Pulmonary
2. Systemic
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To body
Left
atrium
From
lungs
AV valve
Left
ventricle
AV valve
Right
ventricle
Figure 17.13
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Heart
 The sino-atrial
node (SA node)
is the pacemaker
and stimulates
the heart to beat.
 Valves prevent
backflow of blood
during and
between
contractions
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From
body
To body
Semilunar
valves
To lungs
SA node
Right
atrium
Left
atrium
From
lungs
AV valve
Left
ventricle
AV valve
Right
ventricle
Figure 17.13
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
 The SA node stimulates both atria to contract
 Pumps blood into ventricles
 0.1 sec later, both ventricles contract
Cardiac Cycle
 Systoli = ventricular contraction
 Diastole = ventricular relaxation
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Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Cardiac Cycle
 Systoli = ventricular
contraction
 AV (atrioventricular)
valves close
 Diastole = ventricular
relaxation
 Semilunar valves
close
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Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Vascular system includes
 Arteries
 Capillaries
 Veins
Capillaries
Lung
Heart
Vein
Kidney
Artery
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Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Arteries
 carry blood away from
heart
 have thick elastic walls
that expand with the
contraction of ventricles
Capillaries
Lung
Heart
Vein
Kidney
Artery
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Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Capillaries
 thin, porous walls
 where the exchange of
gasses occurs
 Some plasma is forced
out of the capillaries by
blood pressure
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Capillaries
Lung
Heart
Vein
Kidney
Artery
Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
From arteries
To veins
High blood pressure
forces material out.
Muscles that
can cut off
blood flow
through
capillary bed
Capillaries
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Materials are absorbed into
the bloodstream down their
concentration gradient.
Figure 17.15
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Veins
 carry blood to heart
 thinner walls than
arteries
 Have valves
 skeletal muscles aids
the movement of blood
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Capillaries
Lung
Heart
Vein
Kidney
Artery
Figure 17.14
17.2 Spreading the Effects of Smoke: The
Cardiovascular System - Blood Vessels
Veins are only vessels with Valves
•Veins have very low
blood pressure
•Valves keep blood
moving in one direction
•Skeletal muscles act as
‘secondary pumps’
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Figure 17.16
17.2 Spreading the Effects of Smoke: The
Cardiovascular System
Two parallel systems
1. Pulmonary
2. Systemic
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Figure 17.17
17.2 Spreading the Effects of Smoke –
Smoke and Cardiovascular Disease
 Most cardiovascular damage from
smoking is caused by nicotine.
 In high doses, nicotine is toxic to mammals.
 Nicotine increases production of LDL and
decreases production of HDL, which can
lead to atherosclerosis.
 Nicotine stimulates blood clot formation,
which can result in stroke or heart attack.
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17.2 Spreading the Effects of Smoke - Smoke
and Cardiovascular Disease
PLAY
Animation—The Cardiovascular System
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17.3 Removing Toxins From the Body
The Excretory System
Major organs
 Kidneys
 Ureters
 Bladder
 Urethra
Kidney
Ureters
Bladder
Urethra
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Figure 17.19
17.3 Removing Toxins From the Body Kidney Structure and Function
 Nephron = functional unit of the kidneys,
where filtration of wastes occurs
 Each kidney contains about 1,250,000
nephrons.
 Each kidney filters about 1000 liters of blood
every day.
 Capillaries surround nephrons; wastes
diffuse out of blood.
 Collecting ducts = collect fluids from
nephrons and concentrate waste by
absorboing fluids
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17.3 Removing Toxins From the Body –
Kidney Structure and Function
4 phases of urine
production
1. Filtration
2. Reabsorption
3. Secretion
4. Osmotic
concentration
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Blood
1 Filtration: Blood
pressure forces
plasma into the
nephron through
tiny holes in the
adjacent capillaries.
2 Reabsorption:
Sugars, amino
acids, and water are
reabsorbed into the
kidney tissue
across the nephron
loop. Salt actively
removed from the
filtrate on the
ascending limb of
the nephron loop
becomes
concentrated in
Water
the interior of the
kidney, causing
water to flow out
passively.
Toxins
Salts
3 Secretion: Wastes
that are in low
concentration in the
blood are actively
secreted into the far
end of the nephron.
4 Excretion: After
the filtrate is further
concentrated as the
tube extends into
the salty tissue of
the kidney, urine is
excreted into the
bladder.
Figure 17.20
17.3 Removing Toxins From the Body Smoking and the Excretory System
Smoking has a severe impact on the
excretory system
 Probably related to increased blood
pressure, which strains nephrons
 Increased particulate load also stresses
kidneys with increased waste removal
 Smokers have 38% higher incidence of
kidney cancer
 Bladder cancer 3 times more common in
smokers
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17.3 Removing Toxins From the Body Smoking and the Excretory System
PLAY
Animation—The Mammalian Kidney
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