Download The Circulatory System

The Circulatory System
Section 3.3 p. 135 - 140
Learning Outcomes
• I can describe the role and function of the circulatory system
• I can list and describe the individual organs that make up the
circulatory system, and how they work together
• I can describe the how circulatory system responds to changing
conditions
The Role of the Circulatory System
•The circulatory system's job is to deliver nutrients and
oxygen to the cells of the body, and to move waste
products (CO2) to the necessary organs where they can be
expelled from the body
The Heart
• The heart is the pump that powers
the circulatory system
• About the size of your fist
• It consists of
• Two different circuits
• Right side receives deoxygenated blood
from the body, and sends it to the lungs
to become oxygenated
• Left side receives oxygenated blood
from the lungs, and then pumps it to the
rest of the body
• Atriums: Receive blood into the heart
• Ventricles: When they contract they
pump blood out of the heart
Heart
Heart Valves
• Valves prevent the backflow of
blood keeping it flowing in the
right direction
• 4 Valves present in the human
body
• They are forced open the Atrium
contractions
• Forced closed by the Ventricle
contractions
• The opening and closing of these valves is
responsible for the lub/dub sound you hear
• Deficiencies with those valves results in a heart
murmur
Blood Vessels in your body
• These are tubes that carry blood to
and from the Heart
• Inside diameter is referred to as the
lumen
• 3 Main types
• Arteries
• Veins
• Capillaries
• If laid end to end, make up 60 – 100
thousand Km’s
• Lymphatic Vessels, assist but are not
part of the circulatory system
Arteries
• Artery: Thick walled
blood vessels that
carry blood away from
the heart
• Arteries branch off to
form smaller vessels
called Arterioles
• Arterioles continue to
branch off into smaller
blood vessels until they
become Capilleries
Capillaries
• Capillaries: Tiny blood vessels that connect
arteries to veins; one cell layer thick and
extremely narrow
• Tiniest of the blood vessels
• Gas (O2→CO2) and nutrient exchange occurs
here due to the extremely thin walls due to
diffusion
• Form networks that allow cells to be no farther
away than 2-3 cells
• Exchange only occurs in the Capillaries
• The narrowness forces the forces the blood
cells to pass single file
• Capillaries merge with others to form Veinules
Veins
• Veins: blood vessels that return
blood from the body to the heart
• Veins contain valves known as
Veinous Valves
• Just like the heart valves, these valves
are designed to prevent backflow
• They are needed due to low blood
pressure in the veins
• When they malfunction they create a
condition referred to as varicose veins
• Two main veins that return blood
to the heart are the superior and
inferior vena cava
Blood pressure in your body
• Is a measurement for the pressure
required by the heart to pump blood
from the left ventricle all the way back to
the right atrium
• Pressure will be highest in the arteries
closest to the heart
• Pressure will be the lowest at the veins
(Vena Cava) returning blood back to the
heart (the system provides just enough
pressure to return the blood back to the
heart
• Arteries are used when measuring both
blood pressure, and pulses for this reason
Blood Pressure Continued
• Blood pressure is expressed in units of mmHg
(common unit for pressure)
• Results in the measurement at two different
time
• Systolic: Ventricle contracted
• Diastolic: ventricle relaxed
• Normal body pressure is 120 mm/Hg over 80mm/Hg
• Measured by a Sphygmomanometer (works by
listening for sounds)
• Pulse allow you to record heart beat, due to the
elasticity and recoil of the blood flowing through an
artery
Blood
• Is a fluid connective tissue that flow
through the heart and blood vessels
• Second largest example of connective
tissue in your body (behind bones)
• 4 Main Components
• Plasma
• Red Blood Cells
• White Blood Cells
• Platelets
• 5-6 liters in the human body
• Circulates the body approximately
every minute
Plasma
• Plasma: is the liquid
portion of the blood
• Water accounts for 90%
of the plasma makeup
• Makes up about 60% of
the blood
• Suspended in the
plasma are the cells
(elements of the blood)
Red blood cells
• Make up 99% of the “Elements” in
the plasma
• They are what give blood it color
• Referred to as Erythrocytes (red)
• Are Disc Shaped
• Both top and bottom have
concave compressions
Red Blood Cells Continued
• Cells are unique in that
they have no Organelles
• Contain large amounts
of Hemoglobin
• Job is to carry O2, and
to remove CO2
• Average life span is 120
days (4 months)
• Break down quicker due
to no nucleus
White Blood Cells
• Are specialized to fight infection
• Play an important role in the
immune system
• Many different types (5 types)
• Neutrophils engulf bacteria
• This occurs when our inflammation
response occurs
• Your body responds to a cut/potential
source of infection
• Phagocytes such as neutrophils are
sent to the compromised area
• To encourage this blood vessels dilate
(widen) to increase blood flow to the
compromised site
Platelets
• Function is the
formation of blood
clots to stop
bleeding, and allow
healing to occur
• Very Short life span
• Only a week
• Derived from larger
cells known as
Megakaryocytes