Transcript 10D bio 05 circulatory system

The Circulatory System
SBI3U
Interesting Facts
• Your system of blood vessels –
arteries, veins and capillaries – is
over 60,000 miles long. That's long
enough to go around the world more
than twice!
• The adult heart pumps about 5
quarts of blood each minute –
approximately 2,000 gallons of blood
each day – throughout the body.
Interesting Facts
• When attempting to locate their
heart, most people place their hand
on their left chest. Actually, your
heart is located in the center of your
chest between your lungs. The
bottom of the heart is tipped to the
left, so you feel more of your heart
on your left side of your chest.
• The heart beats about 100,000 times
each day.
Interesting Facts
• In a 70-year lifetime, the average human
heart beats more than 2.5 billion times
• An adult woman’s heart weighs about 8
ounces, a man’s about 10 ounces
• A child’s heart is about the size of a
clenched fist; an adult’s heart is about the
size of two fists.
• Blood is about 78 percent water.
• Blood takes about 20 seconds to circulate
throughout the entire vascular system.
Overview of Circulation
• Cardiac circulation:
blood flow within the
heart
• Pulmonary circulation:
blood flow between the
heart and lungs
• Systemic circulation:
blood flow from heart to
rest of the body
The pathway of blood flow
Heart
Vein
Artery
Venule
Arteriole
Capillary
Types of Blood vessels
Vessel
Structure
Function
Artery
Thick elastic walls
Small
circumference
Transports blood
AWAY from the
heart
Vein
Thin, less elastic
walls with valves
Large
circumference
Transports blood
TOWARDS the
heart
Very thin wall
Smallest
circumference
Materials are
exchanged
between the
blood and the
body
Capillary
Diagram
Arteries and veins
B. Longitudinal section
Why blood flows
In arteries:
– Elastic walls expand and contract.
– As they contract, this helps to pump the
blood around the body.
Why blood flows
In veins:
– Valves act as one-way doors to prevent
blood from flowing backwards.
– Muscular contractions can “pump” the
blood
Varicose veins
When valves don’t work properly
The human heart
Direction of blood flow
• Oxygenated blood:
Lungs  Heart  Aorta  Rest of Body
• Deoxygenated blood:
Body  Vena cava  Heart  Lungs
Cardiac Circulation
The heartbeat
• The heartbeat is controlled by the
sinoatrial node (also known as the
pacemaker).
• The SA node sends electrical signals
that cause the heart muscle to
contract.
The SA node and the AV
node
SA node
= sinoatrial node
Defibrillation
A defibrillator can be used on a person experiencing
an irregular or no heartbeat to reestablish a normal
rhythm.
Electrocardiographs
(ECGs)
• The electrical signals of the heart can be
measured using a machine called an
electrocardiograph (ECG).
Cardiovascular disease
ATHEROSCLEROSIS
Treatments
CORONARY BYPASS
Treatments
ANGIOPLASTY & STENT