CHAPTER 9: THE CARDIOVASCULAR SYSTEM
The cardiovascular system of the horse is very efficient resulting in superior athletic abilities. It consists of 3 interrelated components: Blood, Heart & Blood Vessels .
BLOOD
Blood is connective tissue composed of a liquid extracellular matrix called blood plasma that dissolves and suspends various cells and cell fragments. The average horse has approximately 45L of blood, which makes up about 10% of their body weight.
Functions of Blood
1) Transportation : transportation of O2 from the lungs to the cells of the body and CO2 from the body cells to the lungs for exhalation. It carries nutrients from the GI tract and hormones from endocrine glands to other body cells. 2) Regulation : circulating blood helps maintain homeostasis of all body fluids. It helps regulate body temperature by utilizing the heat absorbing and coolant properties of the water in blood plasma. Blood also regulates water content in cells through blood osmotic pressure (mainly through interactions of dissolved ions and proteins). 3) Protection : clotting can protect against excessive blood loss of the cardiovascular system after an injury. White blood cells also are an important part of the body’s immune response. Many blood proteins help the body to fight disease.
Components of Blood
Blood has 2 main components :
1) Blood Plasma : the watery liquid extracellular matrix that contains dissolved substances (proteins, antibodies, hormones)
2) Formed Elements : cells and cell fragments
Blood can be separated into the above 2 parts through a centrifuge (spinning). Blood is ~ 45% formed elements and 55% blood plasma.
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