Chapter 27
Circulation
Chapter 27
Circulatory System Basics
Fluid—blood
Channels—vessels
A pump—the heart
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Chapter 27
Types of Circulatory Systems
Open
• Open space within the body cavity—hemocoel
• Arthropods (insects, spiders, and crustaceans)
• Most mollusks (snails and clams)
Closed
• Confined blood in continuous vascular network
• Pumping heart
– Some invertebrates (earthworm, cephalopod mollusks)
– All vertebrates
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Chapter 27
Open & Closed Systems
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The Evolution of the
Vertebrate Heart
(b) Amphibians
(a) Fish Gill
Reptiles”
Capillaries
Lung
Capillaries
Ventricle
Chapter 27
(c) Mammals,
Birds Lung
Capillaries
Atria
Atriu
m
Ventricle
Body Capillaries
Body Capillaries
Ventricles
Body Capillaries
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Vertebrate Circulatory
System: Functions
Chapter 27
Transport of O2 and CO2
Distribution of nutrients
Transport of waste
Distribution of hormones
Regulation of body temperature
Protection against blood loss and disease
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Chapter 27
Mammal Circulatory System
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Vertebrate Circulatory
System: The Heart
Chapter 27
Structure
• Atria
• Ventricles
• Structural evolution among the vertebrates
The cardiac cycle
• Systole—period of ventricle contraction
• Diastole—relaxation of all the chambers
followed by contraction of the atria
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Chapter 27
Heart - Human
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Aorta
Superior
Vena Cava
(from upper body)
Pulmonary Artery
(to right lung)
Pulmonary Veins
(from right lung)
Right
Atrium
Atrioventricular
Valve
Right Ventricle
Inferior Vena Cava
(from lower body)
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Chapter
27
Human Heart
Pulmonary Artery
(to left lung)
Pulmonary Veins
(from left lung)
Left Atrium
Atrioventricular
Valve
Left
Ventricle
Semilunar
Valves
Descending Aorta
(to lower body)
Chapter 27
11
The Cardiac Cycle
Oxygenated
blood from lungs
Deoxygenated
blood to lungs
(c) Heart Relaxes;
atria fill passively
Oxygenated
Deoxygenated
blood from body blood to body
(a) Atria Contract
(b) Ventricles Contract
Chapter 27
Cardiac Cycle
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Chapter 27
Path of Blood Flow
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
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Chapter 27
Measuring Blood Pressure
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Chapter 27
The Structure of Cardiac Muscle
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Chapter 27
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Coordination of Heart Activity
Atrioventricular and semilunar valves
The sinoatrial node (SA node)
The atrioventricular node (AV node)
Influences on heart rate
• Parasympathetic nervous system - decreases
heart rate
• Sympathetic nervous system - increases
heart rate
• Hormones
Chapter 27
Sinoatrial
Node
Atrioventricular
Node
Excitable
Fibers
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The Heart’s
Pacemaker
and Its
Connection
s
Chapter 27
Cardiac cycle
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Chapter 27
Stab Wound - Heart
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Chapter 27
Composition of Blood
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Chapter 27
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Blood Cells
Red blood cells—erythrocytes (RBCs)
• 99% of the total cellular component in the blood
• Carry O2 bound to hemoglobin from lungs to tissue
• Buffer CO2 carried from the tissues
White blood cells—leukocytes (WBCs)
• 1% of the total cellular component of blood
• Five white blood cell type
Platelets
• Cellular fragments from megakaryocyte in the
bone marrow
• Function in blood clotting
Chapter 27
Blood Smear
Neurtophil
Red Blood Cell
Lymphocyte
White Cell
Platelet
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Chapter 27
Red Blood Cells (Erythrocytes)
Red Cells
Made in the bone marrow
Destroyed in the liver
Stored in the spleen
Heme + Globin + Iron = Hemoglobin
Anemia = Lack of red blood cells
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Chapter 27
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Hemoglobin
Polypeptide Chains
Heme Group
RBCs
RBC Regulation by
Negative Feedback
Chapter 27
Oxygen deficiency
Stimulates
Erythropoietin
production
by kidneys
Stimulates
Red blood
cell production
in bone marrow
Inhibits
Restored oxygen
level
Causes
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Chapter 27
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White Blood Cells - Platelets
White Blood Cells
Made in the Bone Marrow
Programmed in the lymph glands and thymus glands
Platelets
Made in the bone marrow
A White Blood Cell
Attacks Bacteria
Chapter 27
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Macrophage
Bacteria
Pseudopodia
Chapter 27
The Production of Platelets
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Chapter 27
Blood Clotting
Ruptured Platelet
Thromboplastin
B
L
O
O
D
prothrombin
Fibrinogen
Thrombin
Fibrin
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Chapter 27
Blood Clotting (a)
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Chapter 27
Blood Clotting (b)
Fibrin
Network
Platelets
Trapped
RBCs
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Chapter 27
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Blood Vessels
Arteries and arterioles
• Thick walled, elastic to withstand high pressure
• Carry blood away from the heart
Capillaries
• Tiniest vessels; thin, single-cell wall for easy
diffusion
• Exchange of materials between blood & body cells
Venules and veins
• Thin-walled vessels surrounded smooth muscle
• Low resistance to blood flow
• Return blood to the heart
Chapter 27
Blood Vessels
Smooth Muscle
Vein
Artery
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Chapter 27
Distribution of Blood Flow
Regulated by muscular walls of arterioles
Influenced by:
• Autonomic nerves
• Hormones
• Other chemicals released from nearby
tissues
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The Human Circulatory System
Chapter 27
Carotid
Artery
Jugular
Vein
Aorta
Superior
Vena Cava
Heart
Inferior
Vena Cava
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Chapter 27
Femoral
Artery
Femoral
Vein
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Precapillary
Capillaries
Interconnections &
Sphincters
Chapter 27
Structures Blood Vessels
Arteriole
Venule
Conn. Tissue
Muscle
Conn. Tissue
Artery
Endothelium
Vein
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Valves Direct Flow of
Blood in Veins
Skeletal muscles help
return blood to heart
Valves prevent backflow
Chapter 27
38
Chapter 27
The Lymphatic System
Structure
• Complex network of thin-walled vessels
• In proximity to the capillary network
• Composed of cells with openings between
them that act as one-way valves
Functions
• Removal of excess fluid
• Transport of fats from the intestine
• Cellular body defenses
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Tonsil
Superior
Vena Cava
Heart
Thoracic
Duct
Lymph
Vessels
Thoracic Duct
enters vena cava
Chapter 27
40
Lymphatic System
Thymus
Spleen
Valve
Lymphocytes
Lymph Node
Lymph
Fluid
Chapter 27
Lymph conducted to
larger lymph vessels
Capillaries leak plasma
to form interstitial fluid
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Lymph
Capillary
Structure
Interstitial fluid enters
lymph vessels
PlaquesChapter 27 42
Clog Arteries
Chapter 27
Normal Artery - Plaque
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Chapter 27
The End
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