Download Circulatory System

Welcome Back!
• Quiz today postponed to Friday
• Friday Jan 13th: QUIZ Blood Components +
Blood Types
• Tuesday Jan 17th: QUIZ Heart + Circulation
anatomy
• Thursday Jan 19th: QUIZ Lymphatic System
• Friday Jan 20th: TEST Circulation System +
Lymph
• Tuesday Jan 31st: Midyear Exam
Blood Vessels
• Capillaries
– Smaller, branched off, narrow arteries called
arterioles branch off and narrow further into
capillaries
– Smallest blood vessels Fig. 6.34
– So narrow that 1 RBC travel single file through
them
– Walls are very thin (made up of single cell layer)
– Thin walls ease exchange of O2 and CO2 between
blood and organ cells (as well as nutrients and
waste)
Blood Vessels
• Veins
– Veins in lower parts of body (eg: leg) blood must
flow against gravity
– Veins have valves to keep blood from flowing
downward
• Pg 183 Fig. 6.35
– Once the capillaries have
irrigated the organs
(flushing or washing out)
they unite to venules, that
turn into larger veins
– Blood travels from the
heart through the veins
– Pressure inside vein is very
low
– Blood moves forward to
return the heart with
muscular contractions
– These press against the
veins and cause the blood
to circulate
Path of Blood
• Arteries  arterioles  capillaries  venules
 veins
The Heart
• Heart is an organ that stimulates the
movement of blood
• In an adult it is the size of a fist and is located
between the lungs in the thoracic cage
• What does the inside of the heart look like
and how does it work?
• Fig. 6.37
• Blood flows from
atrium to ventricle
on right and left side
• Blood passes
through valves to do
so (atrioventricular
valves)
• Atrioventricular
valves keep blood
from moving
backwards
Inside the heart
• 4 cavities
– Right atrium
– Right ventricle
– Left atrium
– Left ventricle
• Right atrium linked with right ventricle
• Left atrium linked to the left ventricle
• Right and left side of the heart do not
communicate
– They are separated by a partition:
Septum
Heart and blood vessels
• Several blood vessels are
attached to the heart
• Veins: superior and inferior
vena cava and pulmonary
veins - attached to both atria
(plural of atrium) allowing
blood to enter heart
• Arteries: aorta and pulmonary
arteries – attached to
ventricles to carry blood as it
exits
Function of heart
• Blood enters the Atria, when the heart is at
rest and relaxed
– Filling phase = DIASTOLE
• Atrias contract simultaneously forcing blood
into Ventricles, then Ventricles contract
forcing blood into arteries of the heart.
– Contraction phase = SYSTOLE
• Pulse you feel in your throat or wrist is from
the contraction of the left ventricle
– Heart rate vary from person to person…why?
– Best to take Resting Heart Rate lying down!
Circulation Routes Pg. 185
• Since the heart is split
into 2 parts (by the
partition) blood can be
pumped out of each
side along 2 different
routes
– Right Side = Pulmonary
Circulation
– Left Side = Systemic
Circulation
• Use red and blue to colour oxygenated and
deoxygenated blood on diagram
• Worksheet
• P. 195 # 10 – 15
Heart Bypass Surgery
• If time allows…
• https://www.youtube.com/watch?v=YUAB_THem8