Copyright © 2010 Pearson Education, Inc. Chapter 17 Clearing the Air Respiratory, Cardiovascular,...

Copyright © 2010 Pearson Education, Inc.

Chapter 17

Clearing the AirRespiratory, Cardiovascular, and Excretory Systems


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


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


17.1 Effects of Smoke on the Respiratory System - Diaphragm

Breathing is accomplished by the diaphragm and rib cage.


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

Copyright © 2010 Pearson Education, Inc. Figure 17.3


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.



Each alveolus is surrounded by a network of capillaries—tiny, thin-walled blood vessels

Figure 17.4

Blood in:Low oxygen,high carbon dioxide

Air

Blood out:High oxygen,Low carbon dioxide

(a) (b)


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.

Figure 17.5

Diffusion

Alveolus: oxygen concentration high,carbon dioxide concentration low

O2

CO2

Capillary: oxygen concentration low,carbon dioxide concentration high


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 4Figure 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

Figure 17.6

Heme group

Oxygen (O2)

Iron (Fe+++)

Protein chains



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.



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



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


17.1 Effects of Smoke on the Respiratory System - Smoke Particles and Lung Function

Bronchitis

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.


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



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 tissueis notregenerated.

Figure 17.8



Lung Cancer 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

Figure 17.9

Cancerous tumor


17.1 Effects of Smoke on the Respiratory System - Lung Cancer

Animation—Gas Exchange in the LungPLAY


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


17.2 Spreading the Effects of Smoke:

The Cardiovascular System

Three main components1. Circulating fluid (blood)

2. Pump (heart)

3. Vascular system (blood vessels and capillaries)


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

Figure 17.10



Cellular components of blood are produced by stem cells in the bone marrow.

Figure 17.11

Blood stem cell Blood stemcell

Platelet-producingcell

Redblood cells

Platelets Whiteblood cells



Red blood cells 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

Figure 17.12

Fibrin Platelet

White bloodcell

Red bloodcell



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

Figure 17.12

Fibrin Platelet

White bloodcell

Red bloodcell


17.2 Spreading the Effects of Smoke: The Cardiovascular System - Heart

Heart Structure The heart consists

of four chambers 1. Two atria

2. Two ventricles

Pumps blood through two parallel systems1. Pulmonary

2. Systemic

Figure 17.13

To bodyFrombody

Semilunarvalves

SA nodeRightatrium

AV valve

Fromlungs

To lungs

Leftatrium

Leftventricle

Rightventricle

AV valve


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

Figure 17.13

To bodyFrombody

Semilunarvalves

SA nodeRightatrium

AV valve

Fromlungs

To lungs

Leftatrium

Leftventricle

Rightventricle

AV valve


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

Figure 17.14



Cardiac Cycle Systoli = ventricular

contraction AV (atrioventricular)

valves close

Diastole = ventricular relaxation Semilunar valves

close

Figure 17.14



Vascular system includes Arteries Capillaries Veins

Figure 17.14

Capillaries

Heart

Vein

Artery

Lung

Kidney



Arteries carry blood away from

heart have thick elastic walls

that expand with the contraction of ventricles

Figure 17.14

Capillaries

Heart

Vein

Artery

Lung

Kidney



Capillaries thin, porous walls where the exchange of

gasses occurs Some plasma is forced

out of the capillaries by blood pressure

Figure 17.14

Capillaries

Heart

Vein

Artery

Lung

Kidney



Figure 17.15

CapillariesMaterials are absorbed intothe bloodstream down theirconcentration gradient.

High blood pressureforces material out.

From arteries To veins

Muscles thatcan cut offblood flowthroughcapillary bed



Veins carry blood to heart thinner walls than

arteries Have valves skeletal muscles aids

the movement of blood

Figure 17.14

Capillaries

Heart

Vein

Artery

Lung

Kidney



Figure 17.16

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’


17.2 Spreading the Effects of Smoke: The Cardiovascular System

Two parallel systems1. Pulmonary

2. Systemic

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.


17.2 Spreading the Effects of Smoke - Smoke and Cardiovascular Disease

Animation—The Cardiovascular SystemPLAY


17.3 Removing Toxins From the Body

The Excretory System

Major organs Kidneys Ureters Bladder Urethra

Figure 17.19

Kidney

Ureters

Bladder

Urethra


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


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

Figure 17.20

4

3

1

2

Blood

Toxins

Water Salts

Filtration: Bloodpressure forcesplasma into thenephron throughtiny holes in theadjacent capillaries.

Secretion: Wastesthat are in lowconcentration in theblood are activelysecreted into the farend of the nephron.

Excretion: Afterthe filtrate is furtherconcentrated as thetube extends intothe salty tissue of the kidney, urine isexcreted into thebladder.

Reabsorption: Sugars, aminoacids, and water arereabsorbed into thekidney tissueacross the nephronloop. Salt activelyremoved from thefiltrate on theascending limb ofthe nephron loopbecomesconcentrated inthe interior of thekidney, causingwater to flow outpassively.


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


17.3 Removing Toxins From the Body - Smoking and the Excretory System

Animation—The Mammalian KidneyPLAY

Copyright © 2010 Pearson Education, Inc. Chapter 17 Clearing the Air Respiratory, Cardiovascular,...

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