Download The Heart and Circulation - Verbum Dei High School Science

Unit 7
Human biology
The heart and the circulation
LT 6.10.6
SWBAT describe and compare the main functions
of human body systems and organs
LT 6.10.7
SWBAT explain how at least two body systems are
interdependent and function together to carry out
an essential life process
Hook
• http://www.youtube.com/watch?v=ULRfir4xdU
Heart-beat
• What do you notice about this sound?
http://www.youtube.com/watch?v=o5m4ypjBnqE
IBE – JTPS (Justify – Think Pair Share)
Each day your heart beats about 100,000 times,
circulating blood through nearly 96,000
kilometers of blood vessels—roughly onequarter of the distance to the moon. Over 70
years, your heart will beat about 2.5 billion
times.
How can it keep going?
J-TPS (Justify –Think Pair Share)
THINK
PAIR
SHARE
The heart is a muscular pump that
moves the blood through the body
• Cardiac (heart)
muscles work
continuously without
tiring.
NORMAL HUMAN HEART
The heart has four chambers: two atria, two
ventricles
• Valves in each chamber prevent backflow of blood
• Muscles squeeze the chambers in a powerful
pumping action
pulmonary valve
aortic valve
left atrium
right atrium
mitral valve
left ventricle
tricuspid
right ventricle
septum
The heartbeat consists of two contractions
– SA node, or pacemaker,
stimulates the atrium to
contract
– VA node stimulates
ventricles to contract
SA node
VA node
The Heart and Circulation
– oxygen-poor blood enters right atrium, then the right
ventricle
– right ventricle pumps blood to lungs
– oxygen-rich blood from lungs enters left atrium, then the
left ventricle
– the left ventricle through the aorta pumps oxygen-rich
blood to the rest of the body
Heart anatomy
• http://www.youtube.com/watch?v=H04d3rJC
LCE
The heart pumps blood through two
main pathways
Pulmonary Circulation
Systemic Circulation
Pulmonary circulation occurs between
the heart and the lungs
• oxygen-poor blood enters lungs
from the right ventricle of the heart
• carbon dioxide diffuses into the
alveoli
• oxygen diffuses into the blood
• oxygen-rich blood returns to the left
atrium of the heart
Systemic circulation occurs between
the heart and the rest of the body
– oxygen-rich blood goes to organs,
extremities
– oxygen-poor blood returns to heart
Systemic and pulmonary circulation
• http://www.youtube.com/watch?v=AYcTfNY0
QkM
Check your understanding
• Where does the first contraction of the
heartbeat take place?
1. in the ventricles
2. in the atria
3. in the valves
4. in the septum
Check your understanding
• Which parts of the circulatory system deliver
oxygen-rich blood to the rest of the body?
1. the left ventricle and the pulmonary vein
2. the left atrium and the capillaries
3. the atria and the pulmonary artery
4. the left ventricle and the aorta
Check your understanding
• Pulmonary circulation occurs only between the
heart and the
1.
2.
3.
4.
•
Organs
Lungs
Brain
limbs
Check your understanding
• Systemic circulation occurs between the _______
and the rest of the body
1. Heart
2. lungs
3. Brain
4. limbs
•
Check your understanding
• What is the function of valves in the heart?
1. They separate the two ventricles
2. They prevent blood from flowing backward
3. They open between heartbeats
4. They help pump the blood
•
Check your understanding
• Which is the correct pathway for pulmonary
circulation?
1. left ventricle-lungs-right atrium
2. right ventricle-lungs-left atrium
3. right ventricle-lungs-right atrium
4. left atrium-lungs-left ventricle
•
Arteries carry blood away from the heart
and:
• are under great pressure
• have thicker and more muscular walls than veins
• the middle layer of an artery is made of smooth
muscle and elastic fibers
Veins carry blood back to the heart and:
•
•
•
•
are under less pressure
have thinner walls and a larger diameter than arteries
have valves that prevent backflow
circulation is maintained in the vein by the activity of skeletal
muscles
Capillaries
• Capillaries move blood between veins, arteries, and
cells
• Materials can diffuse into and out of blood in the
capillaries because the capillary walls are very thin
Arteries and veins
• http://www.youtube.com/watch?v=I93ricIIOm
s
• Blood pressure is a measure of the force of blood
pushing against artery walls.
– systolic pressure:
left ventricle
contracts
– diastolic pressure:
left ventricle
relaxes
• High blood pressure can precede a heart attack or
stroke
• Permanently high blood pressure is called hypertension
Lifestyle plays a key role in circulatory
diseases
• Some choices lead to an increased risk of
circulatory diseases.
–
–
–
–
–
smoking
long-term stress
excessive weight
lack of exercise
diet low in fruits
and vegetables,
high in saturated
fats
http://www.youtube.com/watch?v=ugnERAFq7as
The heart song
• http://www.youtube.com/watch?v=q0s1MC1hcE