Transcript Chapter 03

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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Open & Closed Systems
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The Evolution of the
Vertebrate Heart
(b) Amphibians
(a) Fish Gill
Reptiles”
Capillaries
Lung
Capillaries
Ventricle
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(c) Mammals,
Birds Lung
Capillaries
Atria
Atriu
m
Ventricle
Body Capillaries
Body Capillaries
Ventricles
Body Capillaries
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Vertebrate Circulatory
System: Functions
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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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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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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)
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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
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Cardiac Cycle
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Chapter 27
Path of Blood Flow
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Chapter 27
Measuring Blood Pressure
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Chapter 27
The Structure of Cardiac Muscle
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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
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Sinoatrial
Node
Atrioventricular
Node
Excitable
Fibers
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The Heart’s
Pacemaker
and Its
Connection
s
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Cardiac cycle
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Chapter 27
Stab Wound - Heart
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Chapter 27
Composition of Blood
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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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Hemoglobin
Polypeptide Chains
Heme Group
RBCs
RBC Regulation by
Negative Feedback
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Oxygen deficiency
Stimulates
Erythropoietin
production
by kidneys
Stimulates
Red blood
cell production
in bone marrow
Inhibits
Restored oxygen
level
Causes
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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
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Macrophage
Bacteria
Pseudopodia
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The Production of Platelets
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Blood Clotting
Ruptured Platelet
Thromboplastin
B
L
O
O
D
prothrombin
Fibrinogen
Thrombin
Fibrin
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Blood Clotting (a)
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Chapter 27
Blood Clotting (b)
Fibrin
Network
Platelets
Trapped
RBCs
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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
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Blood Vessels
Smooth Muscle
Vein
Artery
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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
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Carotid
Artery
Jugular
Vein
Aorta
Superior
Vena Cava
Heart
Inferior
Vena Cava
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Femoral
Artery
Femoral
Vein
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Precapillary
Capillaries
Interconnections &
Sphincters
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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
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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
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Lymphatic System
Thymus
Spleen
Valve
Lymphocytes
Lymph Node
Lymph
Fluid
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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