BIOL3030 Lecture Notes - Lecture 12: Lymphatic System, White Blood Cell, Aorta

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12 Jan 2016
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Monday, October 26 2015
Circulation I
 Transport
Everything is pushed to other parts of the body
Ions (salts), proteins. white blood cells etc. Blood is full of complex units
that the body needs to survive.
Vertebrate closed circulatory system
Blood would never leave the transport system
Two components (forming separate networks)
Blood vascular system
Two connected networks
Arteries and veins are connected to one another by bringing fluids
to different parts of the body
Veins: bring blood back to the heart
Arteries: moves blood away from the heart. Typical high pressure
system reflected by the thickness of vessel wall
Capillary: where veins and arteries meet; bridge between the two
(blood is exchanging materials within its surroundings)
When blood needs to release something, it will be transfused
across a capillary membrane
Shift from high to low velocity and shift to high x-sectional area in
the capillaries. This is called Bernoulli’s law, where the
pressure reduces significantly
There is an increase of total blood value coming back to the heart.
Q: Significance of reduced velocity, increased x-sectional
Capillaries would rupture if the pressure increased, so high
pressure is not necessary.
Capillary wall is one cell thin
Along the distance of the capillary, the pressure is highest as a substance
enters the capillary system, pushing against the material.
As it pushes through, there is an area of a static situation, where nothing
is going in or coming out and there is a lower pressure that can draw
that substance back in.
Pressure is needed to deliver nutrients and other things to the body
Lymphatic system
Introduces white blood cells to the blood
Parallels cardiovascular system because of a close association
Not as many lymphatic vessels, though there is a big tube that this
the main part of the system
There isn’t a big pump (like heart) for this system
Function; drain excess fluid out of tissues and deliver leucocytes
Fluid renters the cardiovascular system afterwards
Characteristics of Blood Vessels
Artery -> Arteriole -> Capillary -> Venule -> Vein
Smooth muscle then endolelium lining
Valve in vein, produces change in pressure. If the heart stopped for a few
miliseconds, valve keeps blood from dropping
Endothelium lining in capillaries and the basement membrane; no muscle.
Vasal dilation and vasal constriction
Veins can change their diameter
 Arteries
Endothelium-Derived Ralaxing Factor
Smooth muscle usually contracting relaxes. Controls blood pressure and
alter distribution
Induced by NO released by endothelium, if too little no relaxation
Elastic connective tissue: pressure reservoir
Pressure of the heart \
Tissues surrounds the entire vessel
Q: Why does the blood pressure not fall to zero when the heart
As the heart pumps, that pressure forces the fluid of of part of the heart
and not into the aorta, straining the connective tissue. Pressure is
stored as vessel exposed. Valve is required
Capillary walls are sensitive to pressure
High Blood Pressure
 Stoke
Pre capillary sphincters: round ground of muscle constrict, it
narrows the diameter
Circulatory Plans
Single-Circuit circulation
Blood is being a part from the heart at cross the body
Divided Circulation