Post on 30-Dec-2015
Questions you can answer after learning about the Cardiovascular System:
• Why could you faint if you stand at attention for a long time?
• Why can you feel nauseous if you are in a sudden stressful situation?
• What makes the Boom-boom sound of a heart beat?• How is the heart disconnected during open heart surgery?• Why does your heart rate increase with exercise?• What is a “pacemaker” and what does it do?• What is hypertension? What is hypotension?
Big Questions about the Cardiovascular System:
• Why do we need a cardiovascular system?
• What does blood do?
• How does blood move around the body?
Answer these questions on your own, then share your
answers with a partner.
Answer these questions on your own, then share your
answers with a partner. Watch Tim and Moby explain about
the cardiovascular system and add
more information to your answer!Watch Tim and Moby explain about
the cardiovascular system and add
more information to your answer!
Pulmonary veinVein
Pulmonary artery Artery
Body capillaries
Lung (pulmonary) capillaries
Label the
blood vessels!Label the
blood vessels!
What types of blood vessels are there?• Arteries:
– Carry blood AWAY from the heart– A few, strong vessels
• Veins:– Carry blood TO the heart– More, weak vessels
• Capillaries:– Exchange gases and nutrients in the blood with tissues– Many, very small vessels
Now try to
label this one!Now try to
label this one!
Body capillaries
Body capillaries
Lung capillariesLung capillaries
Pulmonary vein Pulmonary vein
Pulmonary arteryPulmonary artery
Artery
Artery
Vein
Vein
Left VentricleRight Ventricle
Right AtriumLeft Atrium
A closer look…
• What are arterioles?– Small arteries (one artery leads to more arterioles)
• What are venules?– Small veins (small venules lead to one vein)
• How large and flexible are:– Arteries and arterioles?– Veins and venules?– Capillaries? See the diagram on the
next slide!See the diagram on the
next slide!
Thick muscle
(holds high
pressure blood)
Thick muscle
(holds high
pressure blood)
Thin muscle
(only low pressure
blood inside)
Thin muscle
(only low pressure
blood inside)
Thin walls
Allow diffusionThin walls
Allow diffusionValve
(prevents backflow)
Valve(prevents backflow)
ArteryArtery VeinVein
CapillariesCapillaries
Explain the differences
•Which one carries blood away from the heart?
•Which one has thicker muscle?
•Why does it need to be thicker?
•Which one carries blood to the heart?
•Which one has a valve?•Why does it need a valve?
Why are capillaries so small?
BAD stuff going IN
from body tissues:
Wastes, CO2
BAD stuff going IN
from body tissues:
Wastes, CO2
GOOD stuff going
OUT to body tissues:
Nutrients, O2
GOOD stuff going
OUT to body tissues:
Nutrients, O2
They need to DIFFUSE things
IN and OUT
They need to DIFFUSE things
IN and OUT
Are they always filled with blood?
Why would you want to cut off blood flow to capillaries in a certain area?
Small muscles
stop blood flow
Small muscles
stop blood flow
Only the parts that NEED blood right away have it(Many body parts take
turns getting blood)
Only the parts that NEED blood right away have it(Many body parts take
turns getting blood)
Hint: Injury!Hint: Injury!
Changing blood flow… an example
If you are being chased by a
BEAR…
You need to get away FAST!If you are being chased by a
BEAR…
You need to get away FAST!Send blood away
from the digestive system
Send blood away from the digestive
system
Send blood to the brain and musclesSend blood to the brain and muscles
Result: You might feel nauseous because of less blood going to your stomach
Result: You might feel nauseous because of less blood going to your stomach
How does blood get back to the heartafter going through the capillaries?
Muscle pushes on
the veinMuscle pushes on
the vein
Valve lets blood flow
only in one direction
Valve lets blood flow
only in one direction
Blood returns to the heartBlood returns to the heart
How veins work… an example
Activity:
Raise one hand and keep the other
hand down.
Wait 1 minute.
Now look at your palms!
Were your hands different colors?Why?
When guards stand still for a long time, the blood moves down to their feet and can’t get back up. It can cause them to faint.
Explain this using what you know
about veins and valves!
The Heart: A few definitions
• Myocardium– Heart muscle
• Pericardium– Tissue surrounding the heart
• Pericardial sac– Tissue sac with liquid around the heart
Latin roots: Myo = MuscleCardium = HeartPeri = Around
Latin roots: Myo = MuscleCardium = HeartPeri = Around
Aorta
Pulmonary artery
Pulmonary artery
Left Atrium
Pulmonary veins
Pulmonary veins
Vena cava
Vena cava
Semilunar valveSemilunar valve
AV valveAV valve
Left ventricleRight ventricle
Right Atrium
Label the
parts of the
heart!Label the
parts of the
heart!
Watch it happen!
Check out these animations:•The heart parts QUIZ•The heart from the outside•The heart both inside and outside•The valves•The valves from the inside
What makes the sound of your heart beat?
What would happen if…
• You had a hole in your septum (the dividing muscle between the right and left
ventricles)?
• You had a hole between your atria?
• You had a connection between your aorta and your pulmonary arteries?
How do you control heart contraction?
• Systole is…– When the heart muscle contracts
• Diastole is…– When the heart muscle relaxes
• Nodal tissue– Is very special… it has both nerve and muscle tissue
• SA node (sino-artrial node)
– Gets the signal from the brain and makes the atria contract
– Sends the signal to the AV node• AV node (atrio-ventricular node)
– Makes the ventricles contract all together
Pacemaker(SA node)
1 2 3 4
Rightatrium
Rightventricle
AV nodeSpecializedmuscle fibers
ECG
What does blood pressure mean?
• What is your pulse?Does it measure blood flow in arteries or veins?– Your pulse is a wave of blood moving through your
arteries
• What is blood pressure?Which vessels have the highest pressure?– Arteries have the highest pressure, then capillaries,
then veins• Muscles need to push the blood back to the heart through
your veins
• What is normal blood pressure?– Usually around 120 / 80 mmHg
• Why is blood pressure written as two numbers?– The first number means…
• When the ventricles contract and push blood through arteries
– The second number means…• When the ventricles relax and the blood keeps moving
through (at lower pressure)
Which is systolic and which is diastolic pressure?
SystolicSystolic
DiastolicDiastolic
Blood pressure problems
• Hypotension is – when blood pressure is too low
• Hypertension is – when blood pressure is too high
Put the following terms in order:Right Atrium Left Atrium Pulmonary Veins
Venules Arteries Veins
Arterioles Right Ventricle Body Capillaries
Superior/Inferior Vena Cava
Lung Capillaries Pulmonary Arteries
Aorta Semilunar valve Left Ventricle
Semilunar valve AV valve AV valve