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Cardiovascular
System
Bio 107 – Week 9
Learning Objectives
• Describe the path of blood flow in the fourchambered heart
• Describe the structure and function of red blood
cells, white blood cells, capillaries, veins, and
arteries
• Locate and identify the chambers of the heart and
the vessels connected to these chambers
• Describe how the heart helps maintain homeostasis
Cardiovascular System
• Transports gases between sites of internal and
external respiration
• But also:
o Thermoregulation
o Carries glucose to active organs
o Carries hormones, immune system cells
• Cardiovascular system—includes blood, vessels,
and heart
Circulatory System
• Blood vessels
o Arteries—away from heart
o Veins—toward the heart
o Capillaries—tiny vessels connecting the
two
• Generally arteries carry O2
rich blood and veins O2 poor,
but not always
o Pulmonary artery carries O2 poor blood
from heart to lung, pulmonary vein
carries O2 rich from lungs to heart
• Two circuits: Pulmonary and
Systemic
Circulatory System
• Blood flows through arteries via pressure
from heart beats
• Veins have one-way valves, flow is
accomplished largely by muscle
contraction
• Mammals have a double circulation:
o Systemic: body
o Pulmonary: lungs
Circulatory System – The Heart
• Pump that moves blood through
vessels
• Mammals—four chambered heart
o No mixing of O2 rich and O2 poor blood
o Divided circ. allows for separate blood pressures
• Atria receive blood from veins
• Ventricles pump blood into
arteries
• Right atrium receives blood from
body, then to right ventricle, which
pumps blood to lungs
• Left atrium receives blood from the
lungs, then to left ventricle, which
pumps blood to body
Circulatory System – The Heart
• Blood passes through
atrioventricular valves to the
ventricles
o Tricuspid (R) and Bicuspid (L)valves
• Blood passes through semilunar
valves to leave the ventricles
o Pulmonary semilunar valve
o Aortic semilunar valve
• Right atrium receives blood from
body, passes through tricuspid
valve to right ventricle, which
pumps blood to lungs through the
pulmonary semilunar valve to lungs
• Left atrium receives blood from the
lungs, passes through bicuspid
valve to left ventricle, which pumps
blood through the aortic semilunar
valve to body
Circulatory System – The Heart
•
•
•
•
•
•
Superior/inferior venae cavae - Blood
from body to right atrium
Pulmonary Artery - Blood from R
Ventricle to Lungs
o
Oxygen-poor!
o
Oxygen-rich!
Pulmonary Veins - Blood from Lungs to L
Ventricle
Aorta - Blood from L Ventricle to body
Right atrium receives blood from body
through the superior or inferior vena
cava, passes through tricuspid valve to
right ventricle, which pumps blood to
lungs through the pulmonary semilunar
valve into the pulmonary artery to lungs
Left atrium receives blood from the lungs
through the pulmonary veins, passes
through bicuspid valve to left ventricle,
which pumps blood through the aortic
semilunar valve to the aorta and to the
rest of the body
Tracing Blood Through
the Body
Gas Exchange
• Occurs in capillaries
o One cell thick
• Occurs through
diffusion across a
concentration
gradient
o High  Low concentration of
O2
Today
•
•
•
•
Heart Dissection
Cut it “hamburger style”
See:
http://www.biologycorn
er.com/anatomy/circul
atory/heart/heart_disse
ction.html
Structures to Locate
Sheep Heart: p 74-84
• Right Atrium
• Right Ventricle
• Left Atrium
• Left Ventricle
• Superior/Inferior Venae Cavae
• Aorta
• Pulmonary trunk/pulmonary arteries
• Bicuspid valve (Atrioventricular valve)
• Tricuspid valve (Atrioventricular valve)
• Pulmonary semilunar valve
• Aortic semilunar valve
• Septum
• Chordae Tendinae