Transcript Circulatory System

Respiratory System
As always, copy everything in RED
and any pictures you are told to.
What is Respiration?
Cellular respiration = producing energy
(ATP) from the breakdown of molecules in
food in the presence of oxygen
 Respiration = oxygen and carbon dioxide
are exchanged between cells, blood, and
air in the lungs
 What does CPR stand for?-cardiopulmonary resuscitation (rescue
breathing combined with chest
compressions
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Human Respiratory System
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Function: exchange oxygen and carbon dioxide
Structures:
– Nose: filters air as it enters the body
– Pharynx: tube in the back of the mouth (throat)
passes air and food
– Larynx: “voice box” = vocal cords (two folds of
elastic tissue)
– Trachea: “windpipe”
• Epiglottis covers entrance of trachea when you
swallow
– Bronchi: large passageways leading air to each lung
• Bronchioles are branches from bronchi in each
lung
– Lungs: gas exchange
• Alveoli = tiny air sacs clustered at the end of the
bronchioles and wrapped in capillaries
Figure 37-14 The Respiratory System
Section 37-3
Mouth
Pharynx
Larynx
Trachea
Lung
Epiglottis
Bronchus
Nose
Bronchiole
Alveoli
Bronchioles
Diaphragm
Edge of
pleural membrane
Capillaries
Gas Exchange
350 million alveoli in a healthy lung
 Increase surface area for gas exchange across
capillaries
– Oxygen in alveoli diffuses across capillaries into
blood
– Carbon dioxide in blood diffuses across capillaries
into alveoli
 Very efficient gas exchange
– Inhaled air contains 21% oxygen and 0.04% carbon
dioxide
– Exhaled air contains 15% oxygen and 4% carbon
dioxide
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Figure 37-15 Gas Exchange in the Lungs
Alveoli
Section 37-3
Bronchiole
Capillary
Breathing
The movement of air into and out of the lungs
 At the bottom of the chest cavity is a large flat
muscle = diaphragm
 The lungs are sealed in two sacs = pleural
membranes
– When you breathe in (inhale), the diaphragm
contracts and expands the volume of the chest
cavity, creating a partial vacuum in the pleural
membranes, allowing atmospheric pressure to fill
the lungs with air
– When you breathe out (exhale), the diaphragm
relaxes and decreases the volume of the chest
cavity, increasing the pressure in the chest cavity
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Figure 37-16 The Mechanics of Breathing
Section 37-3
Air
exhaled
Air
inhaled
Rib cage
descends
Rib cage
rises
Diaphragm
Diaphragm
Inhalation
Exhalation
How breathing is controlled
Although you can voluntarily hold your
breath, eventually your body will “force”
you to breathe
 Breathing is controlled in the medulla
oblongata in the brain, which is part of the
autonomic nervous system
 Cells monitor the amount of carbon
dioxide in the blood and as it increases,
nerve impulses cause the diaphragm to
contract bringing air into the lungs
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Tobacco creates problems
Smoking tobacco damages and eventually
destroys the protective system by paralyzing
cilia and trapping mucus in airways
 Tobacco contains:
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– Nicotine = addictive, stimulate drug that
increases the heart rate and blood pressure
– Carbon monoxide = poisonous gas that blocks
the transport of oxygen by hemoglobin in the
blood
– Tar = carcinogen (causes cancer)
Respiratory diseases caused by
smoking
Chronic bronchitis = bronchi become swollen and
clogged with mucus, so constant coughing to try
and force the particles out
 Emphysema = respiratory disease due to loss of
elasticity of lung tissue making breathing very
difficult
 Lung cancer = deadly because it spreads to other
parts of body
 Heart disease = narrowing of blood vessels
increases blood pressure and makes the heart
work harder
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Circulatory System
Circulation and Respiration
Each breath brings oxygen rich air into
your body
 Your cells need that oxygen
 Your heart delivers oxygen to your cells
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Working together, your circulatory and
respiratory systems supply cells
throughout the body with the nutrients
and oxygen that they need to stay alive!
Function
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The circulatory system transports
substances including oxygen, nutrients
and wastes to and from cells responding
to changing demands by diffusion (from
high to low concentration along
concentration gradient).
Structure

Humans have a closed circulatory system.
– Blood is pumped through a system of vessels
(In an open system, blood flows in vessels and
sinuses/gills)
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Sometimes the circulatory system is also
called the “cardiovascular system” because:
– Cardio = heart
– Vascular = vessels
 The human circulatory system consists of:
– The heart
– A series of blood vessels
– Blood that flows through them
The Heart
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Located near the center of your chest
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A hollow organ about the size of your fist
composed of cardiac muscle.
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Enclosed in a protective sac of tissue called the
pericardium
Inside there are two thin layers of epithelial and
connective tissue
Contractions of the myocardium, a thick cardiac muscle,
pump blood through the circulatory system
The heart contracts about 72 times a minute
Each contraction pumps about 70 mL of blood
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Septum, or wall, separates
the right side from the left
side preventing mixing of
oxygen-rich blood and
oxygen-poor blood
 Flaps of connective tissue
called valves divide each
side into 2 chambers:
totaling 4 chambers
– Upper chambers receive
blood = atrium
– Lower chambers pump
blood out of heart =
ventricle

Heart
Types of Circulation
Pulmonary circulation = from right side of
the heart to lungs where carbon dioxide
leaves the blood and oxygen is absorbed
 Systemic circulation = from left side of
the heart to organs

– Coronary circulation = through heart tissue
Pulmonary Circulation
The right side of the heart pumps blood from
the heart to the lungs
 In the lungs, carbon dioxide leaves the blood
while oxygen is absorbed.
 The oxygen-rich blood goes into the left side of
the heart
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Systemic Circulation
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The oxygen-rich blood from
the left side of the heart is
pumped to the rest of the
body
Oxygen-poor blood returns
to the right side of the heart
This blood is oxygen-poor
because the cells absorbed
the oxygen and released
carbon dioxide into the blood
The oxygen-poor blood is
ready for another trip to the
lungs to get oxygen again
Figure 37-2 The Circulatory
System
Section 37-1
Capillaries of
head and arms
Superior
vena cava
Pulmonary
vein
Capillaries of
right lung
Aorta
Pulmonary
artery
Capillaries
of left lung
Inferior
vena cava
Capillaries of
abdominal organs
and legs
Blood Flow through the heart

Blood leaves the heart in arteries, and blood returns to heart in veins.
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Oxygenated blood returns from the lungs through the pulmonary veins to the left
atrium.
Oxygenated blood is pumped from the left atrium through the mitral valve to the left
ventricle.
Oxygenated blood leaves the left ventricle through the aortic valve to the aorta,
which is the largest artery of your body.
The aorta branches into various arteries pumping blood through your body.
Deoxygenated blood returns from the top of your body through the superior vena
cava and from the bottom of your body through the inferior vena cava to the right
atrium.
Deoxygenated blood is pumped from the right atrium through the tricuspid valve to
the right ventricle.
Deoxygenated blood leaves the right ventricle through the pulmonary valve to the
pulmonary arteries.
The pulmonary arteries pump blood to the lungs to absorb oxygen and release
carbon dioxide.
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Heart circulation animation:
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html
The Path of Blood– KNOW THIS!!!
Valves
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Blood enters into the atria of the heart,
separated from the ventricles by valves,
preventing back-flow of blood keeping the
blood flowing in one direction
When the atria contract, the valves open and blood flows into
the ventricles
When the ventricles contract, the valves close preventing blood
from flowing back into the atria and blood flows out of the
heart
At the exits of the ventricles, there are valves that prevent
blood from flowing back into the heart
The “lub-dup” sound of your heart is caused by the closing of
the heart’s valves. The “lub” is when the ventricles contract and
blood being forced against the artioventricular or A-V (tricuspid
or mitral) valves. The “dup” is the blood being forced against
the semilunar (aortic or pulmonary) valves.
Figure 37-3 The Structures of the Heart
Section 37-1
Superior Vena Cava
Large vein that brings oxygen-poor blood from the
upper part of the body to the right atrium
Aorta
Brings oxygen-rich blood from the left
ventricle to the rest of the body
Pulmonary Arteries
Bring oxygen-poor blood
to the lungs
Pulmonary Veins
Bring oxygen-rich blood from each
of the lungs to the left atrium
Left Atrium
Pulmonary Valve
Prevents blood from flowing
back into the right ventricle
after it has entered the
pulmonary artery
Right Atrium
Tricuspid Valve
Prevents blood from flowing
back into the right atrium after it
has entered the right ventricle
Aortic Valve
Prevents blood from flowing
back into the left ventricle
after it has entered the aorta
Mitral Valve
Prevents blood from flowing back
into the left atrium after it has
entered the left ventricle
Left Ventricle
Inferior Vena Cava
Vein that brings oxygen-poor
blood from the lower part of
the body to the right atrium
Septum
Right Ventricle
Heartbeat
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There are two muscle contractions in the
heart:
– The atria
– The ventricles
Each contraction begins in a small group of cardiac muscle
cells in the right atrium that stimulate the rest of the muscle
cells = sinoatrial node (SA node)
Since the sinoatrial node sets the pace for the heart it is
also called “the pacemaker”
The impulse spreads from the pacemaker through fibers in
the atria to the atrioventricular node (AV node) and through
fibers in the ventricles
When the atria contract, blood flows into the ventricles
When the ventricle contract, blood flows out of the heart
Blood vessels
Blood circulates in one direction and it is
moved by the pumping of the heart
 As blood flows through the circulatory
system, it moves through three types of
blood vessels:
– Arteries
– Capillaries
– Veins
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Large vessels that carry
blood away from the
heart to tissues of the
body
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Except for the pulmonary
arteries, all arteries carry
oxygen-rich blood.
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Arteries have thick walls of
elastic connective tissue,
contractible smooth muscle, and
epithelial cells that help them
withstand the powerful pressure
produced when the heart
contracts and pushes blood into
the arteries.
Arteries
Capillaries
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The smallest of the
blood vessels
connecting arteries
and veins
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Walls are one cell thick
allowing for easier
diffusion of nutrients and
oxygen from capillaries to
body cells and wastes
and carbon dioxide from
body cells to capillaries
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Veins
Return blood to the heart
Veins have walls of connective
tissue and smooth muscle
 Large veins contain valves that
keep blood flowing towards the
heart
 Many veins are located near
skeletal muscles, so when the
muscles contract, they help force
blood through the veins, even
against gravity
 Exercise helps prevent
accumulation of blood in limbs and
stretching veins out of shape
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Blood Pressure
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The heart produces pressure when it contracts.
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The force of blood on the arteries’ walls =
blood pressure
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Blood pressure decreases when the heart relaxes, but
there must always be some pressure to keep the blood
flowing
Doctors measure blood pressure with a
sphygmomanometer recording two numbers
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– Systolic pressure = force felt in arteries when ventricles contract
– Diastolic pressure = force of blood felt in arteries when
ventricles relax
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Average adult’s blood pressure = 120/80
High Blood Pressure
Also known as Hypertension
 Forces heart to work harder, which may weaken
or damage the heart muscle and vessels
 More likely to develop heart disease and
increased risk of heart attack and stroke
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Heart Attack
A medical emergency
 Coronary arteries (supplying heart blood)
bring oxygen and nutrients to the heart
muscle itself
 Blockage of coronary artery may damage
or kill part of heart muscle (myocardium)
due to lack of oxygen = heart attack
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– Symptoms include: chest pain/pressure,
feeling of heartburn/indigestion, sudden
dizziness, or brief loss of consciousness
Stroke
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Blood clots may break free from vessels and
get stuck in a blood vessel leading to a part
of the brain = stroke
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Brain cells relying on that vessel may begin to die from lack
of oxygen and brain function in that region may be lost
Strokes can also occur when a weakened artery in the brain
burst, flooding the area with blood
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Prevention
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Cardiovascular diseases are easy to
prevent:
– Exercise
– increases
respiratory system’s efficiency
– Weight control
– reduces
body fat and stress
– Sensible diet
– low in
saturated fat reduces risk of
heart disease
– Not smoking
of heart disease
– reduces risk