Transcript 36. Pulmonary circulation

Pulmonary circulation
What is the cardiovascular system?
The heart is a double pump
heartarteries arterioles


veinsvenules capillaries
PULMONARY
With blood returning FROM the CIRCULATION
Body TO the Heart…(via the Vena
Cava):
Right Atrium  Tricuspid Valve  Right Ventricle  Pulmonary Semilunar
Valve Pulmonary Trunk  Pulmonary Arteries (2)  Alveoli in the Lungs 
 Capillaries in the Alveoli
ONCE BLOOD REACHES THE CAPILLARIES – GAS & NUTRIENT
EXCHANGE OCCURS!
In Pulmonary Circulation, this means that Carbon Dioxide is released to the
alveoli in the lungs and Oxygen is picked up by the bloodstream.
 Pulmonary Veins (4)  Left Atrium  Back to Systemic Circulation
REMEMBER…the Left & Right sides of the heart pump blood
SIMULTANEOSLY!
Heart’s position in thorax
• In mediastinum – behind sternum and pointing left,
lying on the diaphragm
• It weighs 250-350 gm (about 1 pound)
Feel your heart beat at apex
(this is of a person lying down)
4
5
CXR
(chest x ray)
Normal male
6
Chest x rays
Normal female
Lateral (male)
7
Starting from the outside…
Pericardium
(see next slide)
Without most of pericardial layers
8
Figure 21-18
7
Superior
vena cava
Capillaries of
Head and arms
Pulmonary
artery
Capillaries
of right lung
Pulmonary
artery
Capillaries
of left lung
Aorta
9
6
2
3
3
4
11
Pulmonary
vein
RIGHT ATRIUM
RIGHT VENTRICLE
5
1
Pulmonary
vein
LEFT ATRIUM
LEFT VENTRICLE
10
Aorta
Inferior
vena cava
8
Capillaries of
abdominal organs
and legs
The double pump
Chambers of the heart; valves
Circulatory System Functions
• Carry O2 to cells and CO2 away from cells
• Deliver nutrients through body (after
absorption in small intestine)
• Carry liquid wastes away from cells (H2O,
salt, urea)
• Help in fighting infections
• Temperature regulation
Figure 21-19
1. Deoxygenated blood arrives at heart
from systemic circuit:
–
–
passes through right atrium and ventricle
enters pulmonary trunk
2. At the lungs:
–
–
CO2 is removed
O2 is added
3. Oxygenated blood:
–
–
returns to the heart
is distributed to systemic circuit
Three circuits
• Pulmonary
– Blood goes from heart to lungs to pick up
oxygen and release carbon dioxide
• Systemic
– Blood pumped out of heart to the rest of the
body
– Sound of heart (lub/dub) made by valves
closing
• Coronary
– Heart muscle itself supplied with oxygen,
Requirements of gas exchange
• Moist environment
– O2 and CO2 must be dissolved to diffuse
– Lungs, gills, moist surface (slime) help
• Surface area--large area allows for more
diffusion
• Cleaned and filtered
• Warmed
Components of Alveolus
Movement of air into body
• Nose--external opening to allow entry
– Air is filtered, cleaned, warmed, moistened
• Enters a series of tubes
– Protected by cartilage to keep tubes firm/open
– Mucus--traps foreign particles
– Cilia-- “sweep” foreign material away from
lungs to be swallowed (or spit/coughed)
Diffusion of gases
• O2 concentration is higher in alveoli than
blood: oxygen diffuses into blood
– Remember High Conc. -> Low Conc.
• At body cells O2 concentration is higher in
blood: oxygen diffuses out of blood
Oxygen Transport
• O2 diffuses from alveoli to the pulmonary capillaries.
• O2-rich blood travels to heart and pumped to the body
• O2 diffuses into cells. In tissues O2 levels are lower
triggers Hb to release O2
• In tissues, CO2 makes blood more acidic and causes Hb to
change shape.
• CO2 diffuses from cells to blood. Travels to heart in form
of Bicarbonate ions (HCO3-)
• Heart pumps blood to lungs where CO2 is released in in
gaseous form and then expelled.
Health of Respiratory System
• Colds
– Caused by virus, Attacks nasal mucous membranes
– Causes cells to produce histamine--eyes to tear, more mucus,
labored breathing
• Pneumonia
– Caused by virus or bacteria, Inflammation of alveoli
– Weak and tired due to less oxygen exchange
• Bronchitis
– Caused by bacteria or virus (cold or flu), Inflammation
of bronchi
– Cough to clear excess mucus
Health of Respiratory system
• Asthma
– May be allergic, or response to stress, exercise,
etc.
– Narrowed breathing passages (bronchi)
– Treated with drugs that relax air passages
Smoking
• Cigarette smoke contains • Cancer and smoking
– Lung cancer from
– Cyanide
smoking
– Cancer-causing tar
– Mouth and throat cancers
– Carbon monoxide
from chewing tobacco
– Radioactive materials • Other problems:
– Nicotine
– Chronic coughing--due
• Addictive
to paralyzed/destroyed
• Increased heart rate and
cilia
narrowed blood vessels
– Emphysema--Labored
breathing due to
inelasticity of alveoli
Cancer and emphysema
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SMOKERS LUNG
EMPYSEMA