The Circulatory System
By Alex Kannel, Anya Novikova,
Carolyn Gee, and Jacob Mingolla
The Circulatory System includes...
- blood: a circulating connective tissue, and is made up
of liquid plasma (water and dissolved materials) and
cells
- blood + interstitial fluid = internal environment (5)
-blood vessels (vascular system): "channels" that
carry blood around the body, to and from all tissues
-arteries, veins, capillaries
-valves: keep blood moving in one direction; prevent
backflow in veins
-heart: muscular pump that moves blood
Function of the Circulatory System:
- rapid internal transport of substances (food,
hormones, metabolic wastes, and gases) to and
from tissues, "highway system" (5)
- blood is the transport medium of circulatory
systems(5)
- maintains favorable internal
conditions
(the volume/composition/temp of interstitial fluid)
(5)
Parts of the Circulatory System:
• Pulmonary Circulation:
o
o
o
delivers blood to and from lungs (oxygenates blood)
travels in a short loop from the heart's right side to capillary
beds in both lungs, then returns to the left side
driven by right side of the heart(5)
• Systemic Circulation:
o travels in a longer loop
o carries oxygenated blood away from the left side of
the heart to the rest of the body, returns oxygen-poor
blood to the right side of the heart
o driven by left side of the heart
• Lymphatic System: flow of blood removes products of
cellular breakdown and bacterial invasion from the body
Circulatory System Structure:
Structure of the Human Heart:
http://www.drugdevelopment-technology.com/projects/xarelto/xarelto1.html
Circulatory System Video:
Type of Blood Vessel: Structure:
Arteries:
Capillaries:
Veins:
- Comprised of smooth muscle
fiber cells that relax/contract
based on signals from the
nervous system to help keep
blood moving(1).
-thick wall
-branch into arterioles, then
capillaries
- Blood vessels of about 5-20
micrometers
- Found in every major organ
- Thin walls (only one cell thick),
made of endothelium cells (5)
-converge to form venules
Function:
-Transports oxygenated blood
away from the heart.
-control blood flow
- diffusion zones b/w blood and
interstitial fluid where gases are
exchanged
- provide Surface Area for gas
exchanges
- close to cells to
increase diffusion rate
-The outer layers consist of 3
-Transports deoxygenated blood
layers of tissue, while the interior to the heart; after gases,
consists of a series of valves
nutrients, and wastes are
which aid in it's function.
exchanged
-thin, stretchy, not as much
-can store blood if flow slows
muscle
down
-muscular to transport low
pressured blood
Main Types of Blood Vessels Cont.
http://qwickstep.com/search/types-of-blood-vessels.html
Both Arteries and Veins are composed of...
•
•
•
•
•
endothelial cells(6)
elastin
smooth muscle
loose fiberous connective tissue
epithelial cells
Arteries:
• carry blood away from
heart(1).
• carry oxygenated blood
• more muscle/elastic tissue
• carry blood under higher
pressure
• do not have valves
Veins:
• carry blood towards heart
(1).
• carry deoxygenated blood
• less muscle/elastic tissue
• carry blood under lower
pressure
• have valves, which help
prevent blood from moving
backwards in the vein
Gas Exchange Diagram:
Gas Exchange in the Circulatory System:
• Diffusion: oxygen (carried in red blood cells) diffuses across
capillary walls into cells if <1mm away, while carbon dioxide diffuses
into blood in capillaries to be returned to the heart(5).
o If too far away (in non-optimal places) diffusion will not occur, but
since capillaries are so small, red blood cells are forced to be
close to the walls
o Hemoglobin - transfers oxygen in the blood from the lungs to the
rest of the body, diffuses into the cells
o When the blood moves closer to its destination, the size of the
blood vessels decreases to the point that gases can freely move
across and out of the blood stream
Factors increasing gas exchange:
lower pH (blood has a pH range of 7.35-7.45)
temperature increases
o increased levels of CO2
o
o
For example, when skeletal muscles become more
active, they increase the temperature and lower the
pH, changing the structure of the hemoglobin and
increasing the amount of oxygen diffused to the cell
(3).
o the thickness of the non-capillary blood vessels
stops gas exchange by being too thick to allow
gas to diffuse through
Gas Exchange in the Circulatory
System (continued):
• Bulk Flow: water and solutes moved across capillary wall because
of ultrafiltration and reabsorption(5).
o Ultrafiltration: at beginning, small amount of protein-free plasma
is pushed out through clefts in capillary wall because outwarddirected force of blood pressure greater than inward-directed
osmotic force
o Reabsorption: at end, there is less blood pressure so inwardosmotic force greater than outward force of blood pressure, so
moves through clefts into capillaries
o net outward movement
o important in maintaining distribution of extracellular fluid between
blood and interstitial fluid
Bibliography
1."Blood Vessels." Ivy-Rose. IvyRose.ltd, n.d. Web. 8 Nov 2010. <http://www.ivyrose.co.uk/HumanBody/Blood/Blood_Vessels.php>.
2. "Circulatory and Gas Exchange Systems." LSU. Web. 8 Nov 2010. <www.biology.lsu.edu>
3. "Human Physiology - Respiration." Eastern Kentucky University. Biology 301. Harvey Project, n.d. Web.
9 Nov. 2010. <http://people.eku.edu/ritchisong/301notes6.htm>
4. "Cardiovascular System." Rose, Lane P. Partners In Assistive Technology Training and Services. N.p., 1
Oct. 2000. Web. 9 Nov. 2010. < http://webschoolsolutions.com/patts/systems/heart.htm>.
5. Starr, Cecie, and Ralph Taggart. Biology: The Unity and Diversity of Life. 9 Har/Cdr ed. New York:
Brooks/Cole Pub Co, 2001. Print.
6. "High Blood Pressure." Weber, Craig. Web. 9 Nov. 2010.
<http://highbloodpressure.about.com/od/highbloodpressure101/p/circ_art4.htm>
7. "Circulatory and Respiratory Systems." Bellermine. Web. 9 Nov. 2010.
<http://cas.bellarmine.edu/tietjen/images/Circulation.htm>