7/31/2019 The Equine Cardiovascular System Guest Lecture
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The Cardiovascular System Guest Lecture
Heart = 13% of the animal's ability to perform work
Weighs 1.1% of body weight for racehorses or 0.7% for normal
horses
Junctions between cells (intercalated disks) - whatever happens
in a
neighbouring cell, happens in that cell too
Horses take breaks (skip heartbeats)
Control system - muscles
Brain tells the heart what the muscles tell brain
Blood flow is determined by pressure and pressure doesn't
know
direction
The arteriole is the gatekeeper that determines where the blood
is
going to flow to the muscle
Peripheral circulation is what controls central
circulationOxygen Delivery System
Respiratory system
Airway
Lungs
Diaphragm, respiratory muscles
Circulation system
Heart
CirculationBlood
Microcirculation
What can slow a horse down?
Lack of energy
Energetics of Exercise
Aerobic
Use glucose and fat
Rate and substrateHighly efficient because it produces much more
energy per unit
of substrate
As long as you can keep on supplying oxygen, you can go
forever
If your rate of aerobic working is limiting, you will slowly
start to
use anaerobic energy and produce lactate
Ex. Eventer going all day
Anaerobic
