Biology 2601A/B Lecture Notes - Lecture 12: Jugular Vein, Femoral Artery, Tachycardia

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18 Nov 2011
Department
Organismal Phys Lecture 12:
Vascular Transport 2 – Closed Circulatory Systems
The Systemic Circuit
Blood is delievering O₂ and nutrients and is picking up the waste products to
deliver them to the kidneys (or lungs if it is CO₂)
Involves the organs and muscles
When linear flow rate is reduced, is due to the cross-sectional area increasing
(↑ in radius = ↓flow rate)
Major Arteries
Muscular, elastic thick walls (smooth muscle and elastin)
Pressure of 10-20 kPa
Very elastic, which it needs to be so can stretch when receives blood from
the heart; therefore allows storage of some elastic energy (in artery wall),
and dampens the pressure differences
Ex: Aorta, carotid artery, femoral artery
(16/10kPa)
Terminal Arteries
(12/8 kPa)
Relatively high pressure as enter heart, but drops as radius ↑’s
Arteries become smaller as they branch out towards the periphery of the
circulatory system; walls of the arteries also become thinner (tension ↓’s too)
Microcirculatory Beds
The systemic arteries ultimately deliver blood to networks of microscopically
tiny blood vessels in all the systemic organs & tissues
Consists of 3 types of vessels
1. Arterioles
2. Capillaries
3. Venules
Right ventricle then increases
pressure to 1.9kPa for passage
through lungs
Veins
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Low pressure
Have a system of one-way valves (helps ensure blood flows continuously to
heart)
Much thinner-walled than arteries
Blood flows from microcirculatory beds back to the heart through a series of
veins of ↑ing diameter
Pressure Drops Across Vascular System
Fluctuations indicated heart beats
At veins pressure will be boosted slightly to go through lungs; will then be
boosted a lot to go through left ventricle to go back through body
What About Birds?
Broadly similar (to us)
Heart pumps more and faster to meet
greater oxygen demands (more beats/min)
Higher pressures
Jugular Anastamosis: the link between the
left and right jugular; connects one side of
the body to the other
Birds can rotate head 180°; will compress one side of jugular but will still be
able to survive because the other one will compensate for it
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