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The Cardiovascular System
Life Science
FLSS
All images used are taken from copyright-free sources e.g. Wikicommons Media or produced by UWS staff.
The Cardiovascular System
• Also called circulatory system
• Blood transports:
– Nutrients and oxygen to cells
– Waste products, eg. Urea and CO2 from cells
– Hormones, heat….
• Important homeostatic role
Consist of:
• Heart (pump)
• Blood vessels (pipes)
• Blood (medium of transport)
Closed Double Circulation
• Closed – all blood is contained in the
blood vessels
• Double - there are 2 anatomically
separate systems of blood vessels
• Blood passes from one circuit to the
other in a defined and ordered way.
Closed Double Circulation
UWS Staff (2015)
CIRCULATORY CIRCUITS
LUNGS
Pulmonary circuit
vena
cavae
Pulm
arteries
RA
Pulm
veins
LA
RV
LV
aorta
Systemic circuit
BODY
UWS Staff (2015)
Closed Double Circulation
• Pulmonary circulation
ONLY carries blood to and from lungs
for gas exchange (low pressure)
• Systemic circulation
supplies oxygen & nutrients to rest of
body tissues, removes waste
materials from tissues (high pressure)
Position of heart
"Blausen 0467 HeartLocation" by BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014".
Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work. Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Blausen_0467_HeartLocation.png#/media/File:Blausen_0467_HeartLocation.png
The Heart
Alexanderpiavas134 (2007) Humhrt2
https://commons.wikimedia.org/wiki/File:Humhrt2.jpg
Theleftorium (2009) Dissected pig heart
https://commons.wikimedia.org/wiki/File:Dissected_pig_heart.jpg
Osnimf (2005) Aorta
https://commons.wikimedia.org/wiki/File:Aorta.jpg
The Heart
staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work. Licensed under CC BY 3.0 via
Wikimedia Commons https://commons.wikimedia.org/wiki/File:Blausen_0452_Heart_BloodFlow.png#/media/File:Blausen_0452_Heart_BloodFlow.png
Internal structure of the heart
"Diagram of the human heart (cropped)" by Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart_(cropped).svg#/media/File:Diagram_of_the_human
_heart_(cropped).svg
Internal structure of the heart
• 4 chambers
–2 atria (upper)
–2 ventricles (lower)
• L ventricle larger than R & has thicker wall
• divided into R & L side by a septum
– no connection (after birth) between R & L
side of heart
Blood vessels and the heart
• Arteries - carry blood away from heart
• Veins - carry blood towards heart
• Superior & inferior venae cavae
2 large veins, enter R atrium
• Pulmonary trunk
1 large artery, leaves R ventricle
• Pulmonary veins
Several medium sized veins, enter L atrium
• Aorta
huge artery, leaves L ventricle
Structure of heart wall
• epicardium – outer layer - visceral
layer of serous pericardium
• myocardium - specialised
interconnected muscle cells (cardiac
muscle)
• endocardium - flat epithelial cells,
permit smooth flow of blood,
continuous with similar cells in blood
vessels
Pericardium
BruceBlaus. (2014)
https://upload.wikimedia.org/wikipedia/commons/6/6f/Blausen_0470_HeartWall.png
Physiology of the
Heart
Beating heart
http://library.med.utah.edu/kw/pharm/hyper_heart1.html
Cardiac cycle
• events of one heartbeat (duration approx
0.85 sec at 70bpm)
• atria & ventricles contract & relax in turn
• systole = period of contraction
• diastole = period of relaxation
CARDIAC CYCLE
LadyofHats (2008)
https://commons.wikimedia.org/wiki/File:Human_healthy_pumping_heart_en.svg
Heart Sounds
• 1st heart sound LUB! (closing of AV
valves)
• 2nd heart sound DUB! (closing of
semilunar valves)
• Damage to heart valves 
backflow/disturbed flow  heart
murmur
"2014ab Coronary Blood Vessels" by OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19,
2013.. Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:2014ab_Coronary_Blood_Vessels.jpg#/media/File:2014ab_Coronary_Blood_Vessels.jpg
Coronary Arteries
What is a heart attack?
Narrowed/Blocked coronary artery
↓
Lack of blood/O2/Nutrients to heart
muscle
↓
Dysfunction/death of cells
↓
Angina
What is a ‘bypass’ operation??
"Blausen 0466 Heart Bypass Surgery" by Blausen Medical Communications, Inc. - Donated via OTRS, see ticket for details.
Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Blausen_0466_Heart_Bypass_Surgery.png#/media/File:Blausen_0466_Heart_Bypass_S
urgery.png
Blood Vessels
Blood vessels
heart pumps blood into blood vessels, these vary
in size, structure & function:
 arteries and arterioles
transport blood away from heart (at high pressure)
 capillaries
link smallest arterioles to smallest venules
ONLY vessels in which exchange of materials
between blood & tissues occurs
 veins and venules
return blood to heart (at low pressure)
Blood vessels
KelvinSong (2013)
http://commons.wikimedia.org
/wiki/File:Artery.svg
Arteries and arterioles
• thick walls - able to withstand high
pressure of arterial blood
• 3 layers:
Inner layer – endothelium
Middle layer – smooth muscle and
elastic tissue
Outer layer – fibrous connective tissue
Capillaries
• capillary bed, dense network every living
cell located close to blood capillary,
constantly bathed in tissue fluid
• v. thin walls (lined by single layer of cells)
• easy diffusion of small molecules between
blood & tissue fluid
• small diameter (3-12 micrometre) about size of red blood cell
• return of tissue fluid - some to capillaries
at venous side of capillary bed.
Capillaries
Arcadian (2006)
https://commons.wikimedia.org/wiki/File:Illu_capill
ary.jpg
Veins and venules
• thinner walls (less muscle & elastic tissue)
• some have valves (prevents backflow of
blood)
Sunshineconnelly (2007)
https://commons.wikimedia.org/wiki/File:Anatomy_and_phy
siology_of_animals_Valves_in_a_vein.jpg
Skeletal muscle pump
OpenStax College (2013)
https://commons.wikimedia.org/wiki/File:2114_Skeletal_Muscle_Vein_Pump.jpg
Varicose veins
National Heart Lung and Blood Institute (2009)
Lakeland1999 (2010)
https://commons.wikimedia.org/wiki/File:Leg_Before_1.jpg
Blood
Blood
• The only liquid connective tissue in
body
• Functions
– Transport
• Oxygen, carbon dioxide, hormones, nutrients, heat
– Regulation
• pH, body temperature
– Protection
• Blood clotting, white blood cells
Constituents of blood
• plasma - transparent fluid
• formed elements
– red cells (erythrocytes)
– white blood cells (leukocytes)
– platelets (thrombocytes)
CC-BY-3.0 (2008)
https://commons.wikimedi
a.org/wiki/File:Bloodcentrifugation-scheme.png
Plasma
medium in which formed elements suspended
• approx 91% water
(solvent,absorbs,transports & releases heat)
• 9% dissolved substances
Plasma
• Water
– Maintenance of blood volume, solvent, vehicle
for carrying substances
• Solutes
– Proteins - e.g fight infection, clotting,
maintenance of blood osmotic pressure, bind
to drugs & many others
– Other solutes - e.g salts (electrolytes),
nutrients, respiratory gases
Formed elements
Produced in red bone marrow
from pluripotent stem cells
"Binucleated neutrophil smear 2009-11-16" by Paulo Henrique Orlandi Mourao - Own work.
Licensed under CC BY-SA 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Binucleated_neutrophil_smear_2009-1116.JPG#/media/File:Binucleated_neutrophil_smear_2009-11-16.JPG
The National Cancer Institute (2011)
https://commons.wikimedia.org/wiki/File:Red_White_Blood_cells.png
Red blood cells
• no nucleus
• cytoplasm rich in haemoglobin (transport of
oxygen)
• biconcave disc - therefore large surface area for
oxygen absorption
• v. small & flexible, can pass through narrow blood
capillaries
"Anatomy and physiology of animals Red blood cells or erythrocytes" by Original uploader was Sunshineconnelly at en.wikibooks - Transferred from
en.wikibooks; transferred to Commons by User:Adrignola using CommonsHelper.. Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_Red_blood_cells_or_erythrocytes.jpg#/media/File:Anatomy_and_physiology_
of_animals_Red_blood_cells_or_erythrocytes.jpg
"Blausen 0761 RedBloodCells" by BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014".
Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work. Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Blausen_0761_RedBloodCells.png#/media/File:Blausen_0761_RedBloodCells.png
White blood cells
•
•
•
•
Larger than red cells
Have nucleus
Many different types
Most function to fight
infection
BruceBlaus (2013)
http://commons.wikimedia.org/wiki/File:Blausen_0909_
WhiteBloodCells.png
Platelets
• Small fragments of cells
• Contain chemicals which
stop bleeding and initiate
blood clotting –
haemostasis
"Blausen 0740 Platelets" by BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014". Wikiversity
Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work. Licensed under CC BY 3.0 via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Blausen_0740_Platelets.png#/media/File:Blausen_0740_Platelets.png