The Circulatory System
by Jessica Hoffman, Katie Shedd, Angel
Blaise, and Jewels Tambone `
The Structure of the Circulatory System:
• Pulmonary Circuit:
o
Takes blood to the capillary
beds in the lungs, then to the
heart where it is pumped out
the aorta and into the systemic
circuit (1).
• Systemic Circuit:
Takes blood from aorta to
blood vessels and down to the
capillary beds in the different
parts of the body where the
oxygen is distributed among
the cells (1).
o The now deoxygenated blood
is taken through the veins to
the heart where it is pumped
into the pulmonary circuit (1).
o
Blood Overview
• Blood: A fluid connective tissue which maintains favorable
conditions and delivers substances (including oxygen) to cells.
Blood is composed of plasma, platelets, and red & white blood
cells (1).
Plasma: The liquid portion of blood which enables transportation for
blood cells and platelets and everything that is absorbed by the
small intestine (1)
o Platelets: Release substances which initiate blood clotting (1)
o

Red Blood Cells: Transport oxygen from the lungs to the cells.
Packed with hemoglobin (an iron-containing pigment that binds with
oxygen & CO2) (1)
o White Blood Cells: Target & engulf damaged, dead, & foreign cells.
Lymphocytes destroy bacteria, viruses, & other disease agents (1).
o
Blood Vessel Structure
Structure (from inside => out)
Arteries: Endothelium,
basement membrane, elastic
tissue, smooth muscle, elastic
tissue, outer coat
Veins: Valve, endothelium,
basement membrane, smooth
muscle along with elastic fibers,
outer coat
Capillary: Endothelium,
basement membrane
The Main Blood Vessels
(Function)
Vena Cava- Main vein in the heart
Aorta- The main artery in the heart
Pulmonary Arteries- The blood vessels that
brings blood to the lungs for oxygen
Pulmonary Veins- Bring back the oxygenated
blood back to the heart
Systemic Veins- The Blood vessels that bring
blood back from all parts of the body
Systemic Arteries- The blood vessel that takes
blood away from the heart to the rest of the body.
Capillaries: Small blood vessels that distribute
nutrients to cells in the body.
all (1)
Gas Exchange
Trachea > Mainstem Bronchi > Terminal Bronchioles (w/o
Alveoli) > Respiratory Bronchioles (w/ Alveoli) (4)
• Bronchiole: A branch of the mainstem bronchi
• Respiratory Bronchioles: Alveoli attached
• Alveoli: Small thin-walled sacs in the lungs where oxygen and carbon dioxide
exchange takes place
Gas Exchange
• Ventilation: Brings air into alveoli
• In the alveoli:
o Oxygen diffuses from lungs to blood
o Carbon dioxide from blood to lungs
• At the ends of the bronchioles, where smaller
molecules can go through gas exchange, blood cells
and larger proteins cannot pass through the gaps
between blood vessels. (4)
Concentration Gradient in Alveoli
• Ventilation: Maintains the concentration gradient of CO2 and O2 between
the alveoli and the blood in the capillaries
• The body needs to get rid of CO2 (a product of cell respiration) and needs to
take in O2 (needed for cell respiration to make ATP) (2)
• Low concentration of carbon dioxide in the alveoli > carbon dioxide can
diffuse out of the blood in the capillaries and into the alveoli. (2)
• High concentration of oxygen in the in the alveoli > oxygen can diffuse into
the blood in the capillaries from the alveoli. (2)
• Ventilation makes possible by getting rid of CO2 in alveoli and adding more
oxygen (2)
http://www.youtube.com/watch?v=5LjLFrmKTSA&feature=related
References:
1) Biology The Unity and Diversity of life. 9TH ed. United States:
THOMSON LEARNING (KY), 2001. Print.
2) "IB Biology Notes - Gas Exchange." IB Guides - Free International
Baccalaureate Study Guides, Notes, Videos and Powerpoints. Web. 25
Oct. 2011. <http://www.ibguides.com/biology/notes/gas-exchange->.
3) "Alveoli Definition - Medical Dictionary Definitions of Popular Medical
Terms Easily Defined on MedTerms." Medicine.net. Web. 25 Oct. 2011.
<http://www.medterms.com/script/main/art.asp?articlekey=2212>.
4) Black, Suzanne, James E. McLaren, and Neil A. Campbell. Biology:
Exploring Life. Boston, MA: Pearson, 2009. Print.