Transcript Gas Exchange and Smoking

Part 2
Non- Infectious
Diseases :
• Cardiovascular disease
• Lung Disease (COPD,
bronchitis,
emphysema)
• Cancer
NON-COMMUNICABLE!!!!
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Infectious Diseases
caused by Pathogens:
Tuberculosis (bacteria)
Cholera (bacteria)
Malaria (protista)
HIV (virus)
COMMUNICABLE!!!!
Sign
 Visible
expression of a
disease
 Doctor can see
these through
examination or
testing
 Ex.
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Sign vs. Symptom  Cannot be
Symptom
High
temperature
Rash
detected by
examination
 Things a patient
feels but a doctor
cannot detect
 Must be reported
by patient
 Ex.
 Headache
 Dizziness
Smoking and Lung
Disease
 Smoke contains substances that effect
Gas Exchange System and
Cardiovascular System
 Small particles less than 2 um can
reach the alveoli
 Filter system of respiratory system is
much slower in bronchioles
particles settle in alveoli settling of
particles leads to influenza,
pneumonia, allergies, asthma
 Mainstream vs. side stream smoke
 MS from filter end
 SS more toxic to resp. system
Tar
• Mixture of
many
chemical
substances
• Carcinogens
Nicotine
• Additive
• Absorbed readily by blood and
travels quickly to brain
• Effects Nervous System
• binds to receptors on neurons in
brain
• Increase release of DOPAMINE
(pleasure
neurotransmitter=addiction)
• Effects Circulatory System
• Increases release of ADRENALINE in
blood  stimulate DECREASE in
diameter of arteries
(VASOCONSTRICTION)= increase
in HR, BP, and BR = decrease in
blood supply to extremities
• Increase likelihood of blood clots
forming
Carbon Monoxide
• Combine
irreversibly with
haemoglobin
(carboxyhaemoglob
in) = decrease
amount of
haemoglobin
available for oxygen
to attach to =
decrease in
oxygen available
to tissues
• Damages lining of
arteries
Effects of Smoking
 Gas Exchange System
 Chronic Obstructive Pulmonary Disease (COPD)
 Chronic Bronchitis
 Emphysema
 Lung Cancer
 Cardiovascular System
 Atherosclerosis
 Coronary Heart Disease (CHD)
Carcinogens in Tobacco
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Nicotine
Tar
carbon monoxide
Ammonia
Formaldehyde
Phenols
Creosote
Anthracene
Pyrene
hydrocyanic acid
Arsenic
lead
Tar
 particulate matter derived from burning organic
compounds
Chronic Obstructive Pulmonary
Disease COPD
 Chronic
bronchitis and
emphysema
 Extremely
disabling
 Causes:
 Pollution
(indoor/outdo
or)
 Smoking
(chemicals is
smoke)
Narrowing of Air Passageways
 Bad!
 2 main causes:
1. Inflammation
 Immune response (inflammatory response)
 Due to infection in respiratory tissue (from
bacteria/particles/pathogens in slow moving mucus)
2. Build up of scar tissue and smooth muscle
 mucus sitting in passageways not being moved
causes constant cough  causes damage to epithelium
 need for more smooth muscle and build up of scar
tissue = narrowed lumen
Chronic Bronchitis
 Increased mucus secretion
 Goblet cells
 Enlarged mucus glands
 Ciliated epithelium weakened or
destroyed
 Ciliated epithelial cells beat LESS
efficiently (cannot effectively move
mucus out)
 Mucus contains dust particles;
become infected with
bacteria/viruses
 Stimulates cough = damage to
airway tissue = airway stiffens and
narrows
 Build up of mucus  blocks
alveoli difficulty in gas exchange
(diffusion distance b/t air in alveoli
and blood in capillaries is greater)
Emphysema
 Smoking causes Inflammation of lungs
 Infection in lungs = inflammation = narrow
airways
 Increase in WBC (phagocytes) in lung tissue
 WBC leave blood and line airways
 Secret enzyme ELASTASE to they can break
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up elastic (elastin) fibers surrounding alveoli
and reach surface of alveoli to destroy bacteria
No more elastin = no stretching/relaxing of
alveoli when breathing
Bronchioles collapse during exhalation
Trap air in alveoli burst; larger air spaces
Decrease SA for gas exchange
Decrease # of capillaries
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Blood vessels in lungs become resistant to blood
flow  pressure in pulmonary artery
INCREASES to compensate for this 
increase in size of RIGHT side of heart
 Decrease oxygen absorbed in blood
 Symptoms shortness of breath, wheezing
 60 million people world wide effected
Asthma
Lung Cancer
 Caused by carcinogens in TAR
 Cause mutations to DNA
 Effects genes that control cell division
 Especially with epithelial cells of
respiratory tissue
 DNA damage  tumor formation
 Forms in lungs AND other parts of gas
exchange system
 Spreads from bronchial epithelium 
lymphatic tissue metastasis 
Secondary tumors form elsewhere
(malignant)
 Symptoms: chest pain, fatigue and
weight loss
Lung Cancer
 Methods to locate
 Bronchoscopy
 Chest x-ray
 CT scan
 Treatment
 Surgery
 Radiotherapy
 chemotherapy
Cholesterol
Important in:
--cell membranes
--Vitamin D synthesis in skin
-Hormone synthesis in ovaries,
testes, adrenal gland
LDL
 Low Density Lipoprotein
 Transport cholesterol from
liver to tissues and artery
walls
 Deposits cholesterol at
damaged site
HDL
 High Density Lipoprotein
 Removes cholesterol from
tissues
 Transports cholesterol to
liver to be excreted
 Protection against
atherosclerosis
Atherosclerosis
 Definition: thickening and loss of
elasticity in walls of arteries
 Caused by build up of plaque in blood
vessel walls
Plaque: rough patch of cholesterol rich
atheroma on artery walls
 Reduces elasticity AND restricts blood
flow
 Atheroma: fatty material containing
Platelets, Dead muscle cells, Cholesterol,
Fibers
 Atheromatous streaks
 Yellow streaks in artery caused by tobacco
smoke or High BP
 Phagocytes rush to damaged area secrete
proteins to stimulate growth of smooth
muscle cells to repair damage
 Cholesterol accumulate in area
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Atherosclerosis
 Effects of Plaque on artery wall
 Growth pushes inwards towards lumen,
reducing blood flow
 Ruptures through lining of artery creating
rough surface lining artery that stimulates
formation of clots forms THROMBUS
(clot )
 THROMBOSIS formation of thrombus
that interrupts blood flow
 Tissues starved of oxygen and nutrients
 Especially dangerous in coronary artery 
heart attack
 Especially dangerous in brain  stroke
 Nicotine and CO increase risk of
developing atherosclerosis
Stroke
 2 major causes
1. Artery in brain bursts and
blood leaks into brain tissue
(brain hemorrhage)
2. Blockage in brain artery due to
atherosclerosis or thrombosis
 Cerebral Infraction
 When brain tissue is starved of
oxygen and dies
 Different degrees of severity
 Different areas effected
Coronary Heart Disease CHD
 Definition: atherosclerosis in coronary artery that supplies
heart muscle with oxygenated blood
 Arteries narrow, heart has to beat harder to get blood to itself 
increase in blood pressure
 Harder for heart to get oxygen and nutrients it needs, esp. during
exercise
 Three types
1. Angina pectoris
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Symptom: severe chest pain during exertion
Caused by severe shortage of blood to heart muscle
No death of heart tissue
Heart Attack (myocardial infraction)
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When large branch of CA is obstructed by clot
Part of heart muscle starved of oxygen and dies
Symptoms: sudden and severe chest pain
Fatal unless treated immediately
Heart Failure
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Caused by blockage to major coronary artery
Gradual damage to heart muscle
Heart weakens and fails to pump effectively
Evidence for Effects of Smoking on Health
 Epidemiological Evidence
 Consists of data collected about people’s smoking habits and their
health
 Large #s of people should be involved
 Look for correlations b/t smoking and particular disease
 Shows that there COULD be a causal relationship between smoking and a
disease (not definite)…ASSOCIATION
 Must gather physiological evidence to state definite relationship
 Experimental Evidence
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Consists of carrying out experiments
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1960s experiments with dogs and other animals
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IV: whether person smokes of not (or how much they smoke)
DV: aspect of physiology
All other variables kept constant
Unethical in humans
Conclusion: smoking increases risk of developing cancer
More ethical experiments now
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Carried out with lungs tissue cells grown in culture exposed to various cigarette
chemicals
Preventing and Treating
CHDs
 Prevention
 Lifestyle choices that reduce risk
factors
 Screening
 Factors that Increase Risk of CHD
 Inheriting particular alleles of genes
 Eating a diet high in saturated fats
and cholesterol
 No exercise
 Obesity
 smoking
Treating CHD
 Medication
 Lower BP
 Decrease clotting
 Prevent abnormal heart rhythms
 Reduce retention of fluid in blood
 Decrease cholestreol concentration in blood
 Coronary bypass
 Piece of blood vessel is taken from another part of body and sewn in
place as alternate route for oxygen to flow from aorta to heart
muscle
 Heart transplant
 Must be heart from person who has just dies
 Similar tissue type
 Patient needs to take immunosuppressant drugs for rest of life to prevent
rejection
Know sequential events and link to
BIG picture!
 Damage to endothelial lining caused by changing/high blood pressure
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(nicotine) and by damaging chemical components (smoking) cause
plaque formation
Exposure of fibrous and smooth muscle tissue leading to increase in
tissue (may protrude into lumen)
Platelet damage and clot formation (nicotine effect plus non-smooth
lining causing turbulent blood flow)—thrombosis
Cholesterol deposition and macrophage attraction to damaged areaatheroma/atheromatous streaking
Overtime, calcium deposition (causes hardening and loss of elasticity)—
atherosclerosis (arteriosclerosis)
Above effects causing narrowing in lumen of coronary artery, reducing
blood flow to cardiac muscle = insufficient oxygen and glucose(angia,
heart attack)
Above effects in coronary artery = Coronary Heart Disease (CHD)
Above effects in arteries serving brain that lead to reduced blood supply
(thrombosis or aneurysm) = strokes