Transcript How are the respiratory and circulatory system connected?

How are the respiratory and
circulatory system connected?
Organs of the respiratory system
• Nose-internal hairs and mucus pick up unwanted
materials
– FYI-remember anthrax? Those particles are small
enough to get past these hairs
– This bacteria releases toxins that cause death
• Sinuses-reduce weight of skull and effect voice
quality
• Pharynx-throat (food travels from mouth to
esophagus) produces sounds of speech
• Larynx-conducts air in and out of trachea and
prevents foreign objects from entering the trachea;
houses vocal cords (made of muscle and elastic
fibers)
• Trachea-windpipe; split into the left and right
bronchi
• Bronchial tree-tubes leading into the air sacs
– Bronchi
– Bronchioles
– Alveolar sacs (made of alveoli)
• Lungs-contain air passages and alveoli
– Right is bigger than the left.
Inspiration vs. Expiration
Inspiration
• Pressure is low in lungs and
alveoli
• Atmospheric pressure
pushes outside air INTO
airways
• Diaphragm contracts and
moves down
• Lungs expand to fill with air
Expiration
• Increase in lung and alveoli
pressure
• Atmospheric pressure
pushes air OUT of the
airways
• Diaphragm relaxes and
pushes back to position
(moves up)
• Air moves out of lungs
• Returning to original shape
Respiratory Air Volume and Capacities
• Respiratory cycle-1 inspiration and 1
expiration
• 4 distinct air volumes
– Tidal volume-air that moves in (or out) during a single
respiratory cycle (500 mL)
– Inspiratory reserve volume-extra volume that enters
during forced inspiration (3000 mL)
– Expiratory reserve volume-extra volume that is forced
out (1100 mL)
– Residual volume-left over volume after maximal
expiration
• Vital capacity-maximum amount of air a person
can exhale after taking the deepest breath possible
– IRV + TV + ERV
• Inspiratory capacity-maximum volume of air a
person can inhale following exhalation of the tidal
volume
– TV + IRV
• Functional residual capacity-volume of air that
remains in the lungs after a person exhales the
tidal volume
• Total Lung Capacity-Vital capacity + residual
volume
What controls breathing?
• Pons and medulla oblongata
-The inspiratory area determines the basic rhythm and is
also responsible for the contraction of the diaphragm.
-The expiratory center is usually inactive during normal
respiration, however during forceful expiration e.g.
during exercise, it is activated by nerve impulses from
the inspiratory area. muscles, resulting in a forced
expiration.
• Pneumotaxic area regulates breathing rate.
– Part of the pons
– Helps to facilitate expiration.
Factors that control breathing
• Chemoreceptors
– Stimulate these and increase breathing
– Stimulated by blood concentration of carbon
dioxide and hydrogen ions
• Chemoreceptors in arterial walls
– Sense low oxygen concentration
• Overstretching of lungs triggers an inflation
reflex.
– Prevent overinflation of lungs
Gas Exchange in the Lungs
Alveolar Gas Exchange
• Respiratory membrane-two layers of
epithelial cells and a basement
membrane that separates the blood
from the alveolar gases
• Gases move due to partial pressure
• Oxygen and carbon dioxide move
from high pressure to a low
pressure-diffusion
– Many factors effect this: surface area
and solubility of gases (emphysema
reduce the surface area so oxygen isn’t
exchanged as well)
Gas Transport-Oxygen
• Oxygen that blood transports is attached to
hemoglobin (iron containing protein)-forms
oxyhemoglobin
– They do not form a strong bond so hemoglobin releases
oxygen easily so it can diffuse into the cells
• RELEASES IN AREAS WHERE PRESSURE OF OXYGEN
IS LOW (diffusion)
– How much oxygen will oxyhemoglobin release?
• Carbon dioxide levels increases
• Blood temperature increases
• pH of blood decrease (acid)
• Hypoxia-deficiency of blood in the tissues
– Decreased arterial pressure (hypoxemia), inadequate
blood flow (ischemic hypoxia), lack ability to transport
blood (anemic hypoxia), or a defect at the cell
Gas Transport-Carbon Dioxide
• Transported back to the lungs as: dissolved in
plasma (7%), binds to hemoglobin, form of
bicarbonate ion
• Bind with hemoglobin called
carbaminohemoglobin (23%)
• Most common form-bicarbonate ion (70%)
– Carbon dioxide reacts with water to form carbonic acid
(carbonic anhydrase speeds this up)
– This will dissociate to form H+ and bicarbonate ions
• At the lungs, dissolved carbon dioxide enters the
alveoli; bicarbonate ion and hydrogen recombine
to form carbonic acid but quickly breaks down
into carbon dioxide and water
What do we breathe out?
BREATHE OUT
• 4-5% is Carbon
dioxide
• 17-18% is oxygen
• 74.9% is inert nitrogen
gas
• 6.2% is water
•
•
•
•
•
BREATHE IN
21% oxygen
0.04% carbon dioxide
78% nitrogen
0.5% water
How does smoking effect this?
• The normal percent of
hemoglobin that bind to
CO (carbon monoxide) is
2%
• Smokers may exceed 20%
• Increased levels prevent
oxygen from binding,
starving tissues of oxygen,
and causing chest pains,
shortness of breath,
fatigue, confusion, and
abnormal heart rhythm
Common disorders
• Asthma-destruction
of airwayss
• Emphysema• Bronchitisalveolar walls lose
inflammation of the
elasticity and
bronchi
remained filled
• Pneumoniawith air during
infection or
exhale (lungs
inflammation of
become
alveoli/fill up with
permanently
fluid and dead wbc
inflated)
Common disorder
• Tuberculosis-caused by bacteria (mycobacterium
tuberculosis); destroys lung tissue and is replaced
by tough fibrous tissue
• Lung cancer-bronchogenic carcinoma
– Starts in bronchial walls
– Goblet cells get bigger and secrete more mucus
– Other cells divide and take up more space