The Circulatory System
Veterinary Medical Applications
c6A
Anatomy of the Circulatory System
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Heart
Veins
Capillaries
Arteries
Lymph vessels
Lymph glands
Anatomy of the Circulatory System
• Each of its components work together to
supply the body tissues with nutrients and to
collect waste.
Functions
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Distribute nutrients
Transport and exchange oxygen an CO2
Remove waste
Distribute secretions of the endocrine glands
Prevent infection
Assist in the regulation of body temperature
The Heart
• Hollow, muscular organ that pumps blood to
all parts of the body
• Located in the thoracic cavity
• Contained in a pericardial sac
The Heart
• The pointed end, called
the apex, is directed
toward the abdomen
The Heart
• The Heart wall has three layers
– Epicardium
– Endocardium
– Myocardium
The Heart
• Mammals and birds have a 4 chambered heart
that contains:
– Right atrium
– Left atrium
– Right ventricle
– Left ventricle
• The two sides are separated by a ventricular
septum
The Heart
• The atrioventricular valves (AV) separate the
atrium and ventricle on each side
• They have flaps of tissue called cusps which
open and close to allow blood to flow in only
one direction, preventing backflow
• Right AV is called tricuspid
• Left AV is called bicuspid
The Heart
• Pulmonary Valve and aortic valve prevent
blood from flowing back into the ventricles
The Heart
• AV Valves
• Pulmonary and Aortic Valves
Sinoatrial Node
• Controls the beat of the heart
• Sends electrical signals to make the heart
pump
Vascular System
• Made up of 3 types of Blood Vessels:
– Arteries
– Capillaries
– Veins
Vascular System
• Arteries
– Blood vessels that carry oxygen rich blood from
the heart to the body
– Thick walls enable them to withstand the pressure
of the beating heart
– They branch out into arterioles
– Arterioles branch into small vessels called
capillaries
Vascular System
• Capillaries
– Tiny, thin walled vessels that
connect arteries to veins
– Located in all bodily tissues
– Allow nutrients, oxygen, and
water to diffuse to the tissues
– Waste products, like CO2,
diffuse from the tissues into
the blood
Vascular System
• Veins
– Blood vessels that return blood to the heart from
all parts of the body
– Capillaries come together to create small veins
called venules
– Venules join together to form larger veins
– For every artery, there is a larger vein counterpart
Vascular System
• Veins
– Have valves that aid in the prevention of backflow
– Assist in the return flower of blood to the heard
with pressure is low
Circulation
• Two Types
– Pulmonary
– Systemic
Pulmonary Circulation
• Takes the blood from the heart to the lungs to
get oxygen
• Oxygenated blood returns to the heart
Systemic Circulation
• The flow of oxygenated blood from the heart
to all of the tissues of he body
• And the return of the un-oxygenated blood
back to the heart
Circulation
Circulation
• Using your textbook or computer, trace both
the systemic and pulmonary circulation of
blood
Blood
• Blood is connective tissue
• 50-65% Plasma
• 35-50% Non-Plasma (cellular)
Blood
• Plasma
– Straw colored liquid containing 90% water and
10% solids (salts, antibodies, hormones, vitamins,
glucose, proteins)
Blood
• Non-Plasma
– Cellular portion of the blood is made up of:
• White blood cells
• Red blood cells
• Platelets
Blood
• Red Blood Cells (Erythrocytes)
– Carry oxygen from the lungs to various organs
– Contain hemoglobin which provides for the red
color
– Biconcave shape provides for oxygen exchange
– Produced in the marrow
Blood
• White Blood Cells (leukocytes)
– Two types
• Granulocytes
– Neutrophils- produced by marrow, fight infection
– Eosinophils-combat infection by parasites and allergens, contain
histamines
– Basophils- rarest of the granulocytes, responsible for
inflammation
• Agranulocytes- produced by lymph nodes, spleen, thymus,
and other lymph tissues
– Lymphocytes-produce and release antibodies
– Monocytes- absorb diseases like bacteria through phagocytosis
Blood
• Platelets
– Also called thrombocytes
– Formed in the bone marrow
– Help prevent blood loss by forming clots
Blood