Circulatory
System
Chapter 37
Function
• Transportation
system
• Brings oxygen,
food, and
chemical
messages to cells
What type of organisms
have Circulatory Systems?
• Large organisms
– cells don’t come into contact
with the environment (need
circulatory system)
• Small organisms
– oxygen, nutrients, and waste
can diffuse directly through
the cell membrane and out of
the organism
Closed vs. Open Circulatory
Systems
• Closed = circulating
fluid (blood) is
contained within
blood vessels (most
vertebrates)
• Open = circulating
fluid enters and
leaves vessels
(insects)
Organs of the Circulatory
System
• Heart
• Blood Vessels
(arteries,
veins,
capillaries)
• Blood
The Heart
• Receives and pumps blood
• size of a clenched fist
• Pericardium = protective
tissue around heart
• Myocardium = heart muscle
• contracts ~72 times/minute
• ~70 mL of blood each
contraction
4 Chambers of the Heart
• Right Atrium: receives
oxygen poor blood from the
body
• Right Ventricle: pumps
oxygen poor blood from the
heart to the lungs
• Left Atrium: receives oxygen
rich blood from the lungs
• Left Ventricle: pumps oxygen
rich blood to the rest of the
body
Circulation Through the Body
• Pulmonary Circulation
– right side
– pumps blood from the
heart to the lungs
• Systemic Circulation
– left side
– pumps blood from the
heart to the rest of the
body
Circulation Through
the Heart
1. Blood gets oxygen in lungs
2. Oxygen-rich blood enters Left Atrium
3. Oxygen-rich blood pumped to Left
Ventricle
4. Oxygen-rich blood pumped to rest of body
5. Oxygen-poor blood returns to Right
Atrium
6. Oxygen-poor blood pumped to Right
Ventricle
7. Oxygen-poor blood pumped back to Lungs
Heart Valves
• Flaps of tissue between
chambers
• Keep blood from going
backwards
• increases pumping
efficiency
• 4 valves in the heart
Heartbeat
• Pacemaker cells in right
atrium trigger heart to
contract
• Contraction flows like a
wave through heart
• Atria Contract = Pumps
blood to Ventricles
• Ventricles Contract =
Pumps blood out of Heart
• Increases during
exercise
Atherosclerosis
• Cholesterol and fats build up
in arteries
• Forms a plaque that prevents
blood passage
• Plaque in heart = Heart
Attack (most common)
• Plaque in brain = Stroke
• Plaque in arms or legs =
Gangrene
• Process sped up by high
cholesterol, smoking, high
blood pressure, stress
Aortic Aneurysm
• The main artery leading out
of the heart weakens
• Balloons and explodes if not
treated
• 15,000 Americans die/year
from aneurysms
• Can be fixed with surgery
• Cause = smoking, high blood
pressure, infection, other???
Congenital Heart Disease
• Structural birth defect of the
heart
• 30,000 babies born with it in
USA each year
• Many Types
– Abnormal passages in the heart or
between blood vessels
– Problems with the heart valves
– Problems with development of the
heart itself.
• A blood vessel
leading to the brain
is blocked by a clot
or ruptured
• No oxygen to brain =
part of the brain
dies
• Result = loss of
movement, speech,
memory, vision, etc…
• 700,000
Americans/year have
a stroke
• #3 Killer in America
Stroke
Blood Vessels
and Blood
Chapter
37-1 and
37-2
Arteries
• Largest blood vessel
• Contain muscle tissue
for contracting
• Almost all carry
oxygen-rich blood
• Carry blood away from
heart to other tissues
• (ex.) Aorta, Carotid
Artery
Veins
• thinner walls
• lined with muscle for
contracting
• large veins have valves to
keep blood moving
towards the heart
• pumps mostly oxygen-poor
blood to the heart
• (ex.) Pulmonary Vein, Vena
Cava
Capillaries
• Smallest
• Walls are one-cell
thick
• Nutrients and
waste pass
through easily
• Important for gas
exchange
Blood Pressure
• The force of blood on artery walls
• Caused by the heart pumping blood
• Sphygmomanometer = measures
blood pressure and gives 2 numbers
(120/80)
– 1st Number = Systolic Pressure =
force felt by arteries when ventricles
contract
– 2nd Number = Diastolic Pressure =
force felt by arteries when ventricles
relax
Blood Functions
• Collects oxygen,
nutrients, and wastes
• Regulates body
temperature
• Fights infections
• Repairs damaged blood
vessels
Blood Plasma
• 55% of your blood
volume
• straw-colored liquid
• 90% water, 10% gases,
salts, nutrients,
enzymes, hormones,
waste, proteins
• what blood cells float in
Red Blood Cells
•
•
•
•
•
Erythrocytes
most numerous cells in the blood
1mL of blood = 5 mill RBC’s
transport oxygen
Hemoglobin = iron-protein that
binds to oxygen (give blood red
color)
• Last ~120 days and then are
destroyed in the liver and spleen
• Shaped like a disk
White Blood Cells
• Leukocytes
• produced in the bone
marrow of large bones
• they guard against
infection, fight
parasites, and attack
bacteria (part of the
immune system)
• # is increased during
an infection
Platelets
• Help to clot blood
• produced in bone
marrow
• stick to broken blood
vessels and form a
barrier until other
cells can permanently
repair the vessel
High Blood Pressure
(hypertension)
• Too much pressure on
arteries/heart works
harder
• Hardening of the blood
vessels, bloodshot eyes,
stroke, kidney failure,
death
• Causes: genetic and
environmental (overweight,
aging, smoking, diet)
• 1 in 4 people
Anemia
• Not enough red
blood cells
• Body can
distribute enough
oxygen
• Tired, weak, pale,
rapid heart beat,
heart failure
Leukemia
• Cancer of the bone marrow
and blood
• uncontrolled accumulation of
functionless cells
• not enough red and white
blood cells made
• easy bruising or bleeding,
paleness, fatigue, recurrent
minor infections, poor healing
cell count)
Hemophilia
•
•
•
•
Absence of proteins that clot blood
unable to stop bleeding from cuts
internal bleeding and deep bruising
could lead to death if untreated
Varicose Veins
• Twisted and enlarged veins
• muscle around vein weakens
from too much pressure
• always on your feet
• occurs mostly in older
women
• mostly a cosmetic problem
Respiratory
System
Chapter 33
Function
• Brings oxygen
to the body and
rids the body
of carbon
dioxide
• Nose and Mouth: where air comes in and leaves,
filter
• Epiglottis: protects food from going down the
trachea
• Larynx: vocal cords/voice box
• Diaphragm: dome-shaped muscle under chest cavity
Major Organs
• Trachea: passage to
lungs/windpipe (tree
trunk)
• Bronchi: 2 branches from
trachea to lungs (main
limbs of tree)
• Bronchioles: very small air
passages (branches and
twigs)
• Alveoli: air sacs in grapelike clusters, where gas
exchange occurs (leaves)
Gas Exchange
• Occurs in the
capillaries on the
alveoli
• Carbon dioxide
waste goes in and
oxygen goes out
• Process of
diffusion
Breathing
• Inhale (breathe in):
diaphragm contracts,
size of chest cavity
increases and fills
with air
• Exhaling (breathe
out): diaphragm
relaxes, chest cavity
size decreases and
pushes air out
• Controlled by brain
stem
Smoking
• Foreign particles are
allowed to enter lungs
• Increased mucus
production (smokers
cough)
• Less air flow to alveoli
(tire easily)
• Tar builds up in lungs,
goes to blood stream =
cancer
Emphysema
• Loss of elasticity in
alveoli
• Makes breathing
difficult (less gas
exchange)
• 85% of cases caused
by smoking
• Quit smoking or
death
Lung Cancer
• Lung cells dividing at
an uncontrollable rate
• Spreads quickly
through out body
• Causes more deaths
than any other cancer
• Over 200,000 deaths
in the USA
• 87% of deaths were
smoking related