6.2 - The Blood SystemNicole Boylan, Ava Gulino & Jack McBride

Basics• Arteries are blood vessels that take blood away

from heart that hasn’t reached capillary• Arteries used by autonomic nervous system; used

to maintain blood pressure• Arteriole- smallest of arteries• Capillary bed- network of capillaries that drain

into single venule

Understandings• Arteries convey blood @ high pressure from the

ventricles to the tissues of the body• Arteries have muscle cells and elastic fibers in

their walls• The muscle & elastic fibers assist in maintaining

blood pressure between pump cycles• Blood flows through tissues in capillaries.

Capillaries have permeable walls that allow exchange of materials between cells in the tissue of the capillary

• Veins collect blood @ low pressure from the tissues of the body & return it to the atria of the heart

Understandings continued• Valves in veins & the heart ensure circulation of blood by

preventing backflow• There is a separate circulation for the lungs• The heart beat is initiated by a group of specialized muscle

cells in the right atrium called the sinoatrial node• This node acts as a pacemaker• This node sends out an electrical signal that stimulates

contraction as it is propagated through the walls of the atria & then the walls of the ventricles

• The heart rate can be increased or decreased by impulses brought to the heart through 2 nerves from the medulla of the brain

• Epinephrine increases the heart rate to prepare for vigorous physical activity

Veins• Veins- Blood vessels that collect blood from

capillaries and return to heart

Heart• Human heart is a pair of side-by-side pumps; form

2 major routes for blood to flow• Right side of heart- pulmonary circulation (lungs)• Left side of heart- systematic circulation (organs)• Majority of tissue that makes up heart is muscle• Sinoatrical node (SA Node)- acts as pacemaker for

heart by sending “electrical signal” to contract

Fun Facts• Heart activity/blood pressure increases during

activity• Fatty/unhealthy foods can cause plaque buildup in

arteries and cause heart attacks• The First artificial heart pacemaker was plugged

into a wall socket!• The Blue whale has the largest heart weighing

over 1,500 pounds!• Your heart beats around 100,000 time a day!• Each minute your heart punmps through about

one and a half gallons of blood!

Online EKG Lab!• http://

www.nobelprize.org/educational/medicine/ecg/ecg.html

Skit• Jack: Oh my goodness! I am having discomfort in

my chest and in my upper body! I am also short of breath and nauseous…

• Ava: What do you think is wrong with him?• Nicole: These might be signs of a heart attack!• Ava: Wow really? What can we do to help him?• Nicole: Let’s call 9-1-1• A link showing what your heart does during a

heart attack: http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=hrtatk

Fun Activities!• https://www.youtube.com/watch?v=ruM4Xxhx32U

Cute video on the heart and its functions.• https://www.youtube.com/watch?v=EA2DY0tjpFI

Slightly less cute video explaining with more detail the heart and its functions.

• http://www.hhmi.org/biointeractive/cardiology-virtual-lab Fun virtual lab!

• Enjoy!