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Circulation &
Respiration
Chapter 42
Circulatory systems
 Closed circulatory system
 Vertebrates
 Blood
 Enclosed in blood vessels & heart
 Lymph
 Lymph system
 Interstitial fluid
Functions
 1. Transportation
 Substances needed for cellular respiration
 A. Respiratory
– CO2 and O2
 B. Nutritive
– glucose
 C. Excretory
– Metabolic wastes, ions, water
Functions
 2. Regulation
– Hormones
– Temperature regulation (Endotherms)
 3. Protection
– Clotting
• Proteins, platelets
– Immune defense
• WBC, AB
Components of the system
 Heart
 Blood vessels
 Blood
Heart
 4 chambered
 Separates systemic & pulmonary
blood systems
 Systemic circulation:
 Blood flow in the body
 Pulmonary circulation:
 Blood flow between the heart & lungs
Circulation
Circulation
Heart structure
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Atrium
Small chambers
Receive blood
Ventricles
Larger chambers
Pump blood from heart
Septum
Separates chambers
Septum
Heart structure
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Valves
Atrioventricular valves (AV)
Between the atrium & ventricles
Tricuspid---right
Bicuspid or Mitral---left
Semilumar valves
Exits from the ventricles
Aortic valve (L ventricle)
Pulmonary valve (R ventricle)
Valves
Heart structure
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Heart sounds
“lub-dub” -valves closing
“lub” closing of the AV valves
“dub” closing of the semilunar valves
Murmur:
Abnormal heart sound
Heart structure
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Superior & inferior vena cava
Brings blood to heart from body
Pulmonary arteries
Blood from right side of heart to lungs
Pulmonary veins
Returns blood from lungs to heart
Aorta
Blood goes from the heart to body
Heart structure
 Coronary arteries
 First branches off the aorta
 Supply blood to the heart
Coronary arteries
Circulation
Path of Blood Flow
Blood flow
 Vena cava
 Right atrium
 Tricuspid valve (AV)
 Right ventricle
 Pulmonary valve (semilunar)
 Pulmonary artery
 Lungs
Blood flow
 Pulmonary veins
 Left atrium
 Mitral valve (AV)
 Left ventricle
 Aortic valve (semilunar)
 Aorta
Blood flow
Blood flow
 Cardiac cycle:
 One cycle of heart filling & emptying
 Diastole
 Heart resting
 Heart filling with blood
 AV valves open
 Semilunar valves closed
Diastole
Blood flow
 Systole
 Ventricles contracting
 Pumping blood out of the heart
 AV valves closed
 Semilunar valves open
Systole
Blood pressure
 Measurement of pressure of blood in the
arteries
 Systolic measures ventricular contraction
 Diastolic measures ventricular resting
 Sphygmomanometer or BP cuff
 Brachial artery
 120/80 normal
Blood pressure
Cardiac output
 Volume of blood pumped by left
ventricle to the body per minute
 5 liters per minute
 Depends on heart rate
 Stroke volume
 Amount of pumped out per
contraction (70 ml)
Cardiac output
 Increases with exercise
 Increased HR
 Better stroke volume
Blood pressure
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Cardiac output
Flow resistance in the arteries
Affect BP
More constriction higher BP
More dilation lower BP
Baroreceptors
Aorta & carotids
Medulla oblongata
Blood pressure
 Depends on blood volume
 Decreased volume
 Decreased cardiac output
 Decreased BP
Conduction
 Depolarization of heart muscle stimulates
contraction
 Heart contains autogenic cells
 Self stimulate
 SA node (sinoatrial)
 Pacemaker of the heart
 Located in R atrium wall
 Near the superior vena cava
Conduction
 SA node
 Causes atrium to contract
 Sends signal to the AV node
 AV (atrioventricular) node
 Located in wall between R atrium &
ventricle
 Sends signal to the bundle of His
Contraction
 Bundle of His
 Sends signal to the Purkinje fibers
 Ventricles contract
 SA⇨AV⇨Bundle of His⇨Purkinje fibers
Conduction
Conduction
EKG
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Electrocardiogram
Records electrical impulses of the heart
P-wave
First wave-atrium contraction
QRS-wave
Ventricles contracting
T-wave
Heart re-polarization
EKG or ECG
Vessels
 Arteries, arterioles
 Veins, venules
 Capillaries
 arteries⇨arterioles⇨capillaries⇨venules⇨veins
Capillaries
Blood vessels
Vessels
 Structure (except capillaries)
 Inner layer is endothelium
 Next is a layer of elastic fibers
 Smooth muscle layer
 Connective tissue
 Capillaries
 Endothelium only
Arteries
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Carry oxygen rich blood away from heart
Arterioles:
Smaller arteries
Larger the artery
More elastic & recoil as blood is pumped
Arteries
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Vasoconstriction:
Contraction of smooth muscle in arterioles
Decrease blood flow
Vasodilation:
Relaxation of smooth muscle
Increase blood flow
Precapillary sphincters:
Regulate blood flow
Veins
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Carry oxygen poor blood to heart
Venules
Smaller veins
Less smooth muscle
Skeletal muscles constrict
Help flow of blood to heart
Venous valves:
Help blood flow to heart prevent backflow
Capillaries
 Passage of oxygen & nutrients
 Into cells or extracellular fluids
 Passage of carbon dioxide & wastes
 From cells to blood
Blood
Blood
Plasma (matrix) yellow
Metabolites, wastes, hormones
Ions
Proteins
Albumin (fluids), globulins (antibodies),
fibrinogen (clots)
 Cells
 RBC, WBC, platelets
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Blood cells
Blood formation
RBC (erythrocyte)
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O2 & CO2 transport
Hemoglobin (protein)
Erythropoietin
Hormone (Kidney )
Stimulates RBC production
Erythropoiesis
RBC production from stem cells
Spleen, bone marrow & liver remove RBC
Heme
Hemoglobin
RBC
WBC (leukocyte)
Larger than RBC
Contain a nucleus
Fights against infection & FB
Interstitial fluid as well as blood
Granulocytes: neutrophils, eosinophils,
basophils
 Non-granulocytes: lymphocytes,
monocytes
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WBC
Platelets
 Megakaryocyte (bone marrow)
 Cell fragments
 Clotting
 First to site of injury
 Fibrin (protein that forms clot)
Platelets
Clotting
 Tissue damage
 Platelets arrive
 Cascade reactions start
 Prothrombin changes to
 Thrombin (enzyme)
 Changes fibrinogen to fibrin
 Forms clot
Fibrin
Blood
 More RBC than WBC
 Hematocrit
 Measurement of RBC’s in the blood
 RBC last about 120 days
Lymph system
 Interstitial fluid
 Fluid from blood plasma that leaves the
capillaries
 Surrounds the tissues
 Lymph:
 Returns to circulation via lymph system
 Lymph nodes, lymph vessels & organs
(spleen & thymus)
Edema
 Swelling of tissues
 Usually ankles or feet
 Interstitial fluid cannot be returned
 Low protein (albumin)
 Liver disease
 Heart disease
 Pregnancy
Varicose veins
 Too much blood in legs
 Valves veins do not work
MI
Flutter
Atherosclerosis
Aneurysm
Infarct
Pacemaker
VSD
MVP