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Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Circulatory and Respiratory Systems
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Most animals have a circulatory system
– That transports O2 and nutrients to cells and takes away CO2 and other wastes
– Must deal with the problem of gravity
How Does Gravity Affect Blood Circulation?
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Circulatory system
• Connects all body tissues
• Arteries, veins and capillaries
Capillary
Nuclei ofsmoothmusclecells
Redbloodcell
LM
70
0
Figure 23.1A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Capillaries
– Are the sites of exchange between blood and interstitial fluid
Capillary
Interstitialfluid
Tissuecell
Diffusion ofmolecules
Figure 23.1B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
MECHANISMS OF INTERNAL TRANSPORT
• Several types have evolved
• Cnidarians and flatworms
• Gastrovascular cavity
– Digestion
– Internal transport
Figure 23.2A
Mouth
Circularcanal
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Open circulatory systems
• Arthropods and molluscs
– Open-ended vessels
– Tissue cells directly
Figure 23.2B
PoresTubular heart
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Closed circulatory systems
– Arteries to capillaries
– Veins return blood to the heart
Artery(O2-rich blood)
Arteriole
Capillary beds
Venule
Vein
AtriumVentricle HeartArtery
(O2-poor blood)GillcapillariesFigure 23.2C
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Vertebrate cardiovascular systems
• Fish
– Two-chambered heart
– Single circuit: gill capillaries -> systemic capillaries -> heart
Figure 23.3A Systemic capillaries
Gill capillaries
Heart:
Ventricle (V)
Atrium (A)
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Vertebrate cardiovascular systems
• On land
– Mostly 4 chambered hearts
– Double circulation
– Separate pulmonary and systemic circuits
Pulmonarycircuit
Systemiccircuit
Right Left
AA
V
Lung capillaries
Systemic capillaries
V
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Amphibians and reptiles
– Three-chambered hearts
Figure 23.3B
Pulmocutaneouscircuit
Systemiccircuit
Right Left
AA
V
Lung and skin capillaries
Systemic capillaries
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
THE MAMMALIAN CARDIOVACULAR SYSTEM
• Heart
– Two thin-walled atria ->
– Pump blood into the ventricles ->
– Thick-walled ventricles ->
– Pump blood away
– Valves prevent backflow
• AV
• Semilunar
Rightatrium
Leftatrium
Semilunarvalve
Semilunarvalve
Atrioventricular(AV) valve
Atrioventricular(AV) valve
Rightventricle Left
ventricle
Figure 23.4A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood flow
• Human cardiovascular system
Figure 23.4B
1
2 7
8
9
2
3
4
5
6
410
3
9
8
Superiorvena cava
Capillaries ofhead, chest, andarms
Pulmonaryartery
Capillariesof left lung
Pulmonary vein
Aorta
Left atrium
Left ventricleAorta
Capillaries ofabdominal regionand legs
Inferiorvena cava
Right ventricle
Right atrium
Pulmonary vein
Capillariesof right lung
Pulmonaryartery
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Heart function
Contracts and relaxes rhythmically
• Diastole
– Relaxed
– Heart chambers fill
• Systole
– Contractions:
• Atria: blood into the ventricles
• Ventricles: blood into the large arteries (stronger)
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Heart function
Figure 23.6
Heart is relaxed.AV valvesare open.
1 2 Atriacontract.
Systole
Diastole
0.4 sec
0.1sec
0.3 sec 3 Ventriclescontract.Semilunarvalvesare open.
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Heart function
• Cardiac output
– Volume of blood/minute pumped into the systemic circuit
– 5 L per minute
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
The pacemaker
• Pacemaker (SA node) generates electrical signals
– Triggers contraction of the atria
• The AV node
– Relay
– O.1 sec delay to ventricles
– ECG
Figure 23.7
1 2 3 4
Pacemaker(SA node) AV node
Specializedmuscle fibers
Apex
Rightventricle
Rightatrium
ECG
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
The Pacemaker
Heart rate
– Adjustable
• Heart attack?
• Heart murmur?
AortaSuperiorVena cava
Pulmonaryartery
Leftcoronary artery
Rightcoronary artery
Blockage
Deadmuscletissue
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Atherosclerosis
Connectivetissue
Smoothmuscle
Epithelium
LM
16
0
LM
60
Plaque
Figure 23.8B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood vessels
• Capillaries
– Wall formed by single layer of epithelial cells
• Arteries and veins
– Have smooth muscle and connective tissue
Figure 23.5
Capillary
Epithelium
Basementmembrane
Valve
Epithelium
Smoothmuscle
Connectivetissue
Vein
VenuleArteriole
Artery
Connectivetissue
Smoothmuscle
Epithelium
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood pressure
– Is the force blood exerts on vessel walls
– Depends on cardiac output and the resistance of vessels
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood pressure
• Highest in the arteries
Figure 23.9A
Pre
ssur
e (m
m H
g)120100806040200
Systolicpressure
Diastolicpressure
Relative sizes andnumbersof bloodvessels
Vel
ocity
(cm
/sec
) 50
40
30
20
10
0
Aor
ta
Art
erie
s
Art
erio
les
Cap
illar
ies
Ven
ules
Ven
ae c
avae
Vai
ns
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood pressure
• Muscle contractions and one-way valves
– Keep blood moving
Skeletalmuscle
Direction ofblood flowin vein
Valve(open)
Valve(closed)
Figure 23.9B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Blood flow• Constriction of arterioles and precapillary
sphincters
– In capillary beds
Figure 23.11
1
2
Sphincters relaxed
Sphincters contractedVenule Arteriole
Venule Arteriole
Precapillary sphincters Thoroughfarechannel
Capillaries
Thoroughfarechannel
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Transfers
Capillaries
TE
M 5
,000
Musclecell
Cleft betweentwo epithelialcells of the capillary wall
Nucleus of epithelial
cell
Capillarywall
Iumen
Interstitialfluid
Figure 23.12A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Transfers
• Movement of materials in and out of blood
• Diffusion
– Through clefts between epithelial cells
Tissue cells
Osmoticpressure
Arterialend of
capillary
Interstitialfluid
Net fluidMovement out
Net fluidMovement in
Bloodpressure
Bloodpressure
Osmoticpressure
Venousend of
capillary
Figure 23.12B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
STRUCTURE AND FUNCTION OF BLOOD
Red and white blood cells suspended in plasma
• Plasma is about 90% water
– Inorganic ions, proteins, nutrients, wastes, gases, and hormones
Plasma (55%)
Constituent Major functions
Water Solvent forcarrying othersubstances
Salts (ions)SodiumPotassiumCalciumMagnesiumChlorideBicarbonate
Osmotic balance,pH buffering, andnerve and musclefunction
Plasma proteins
Fibrinogen
Immunoglobulins(antibodies)
Osmotic balance and pH buffering
Immunity
Clotting
Substances transported by blood
Nutrients (e.g., glucose, fatty acids,vitamins) Waste products of metabolismRespiratory gases (O2 and CO2)Hormones
Centrifugedblood
sample
Figure 23.13 (left part)
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Red blood cells (erythrocytes)
– O2 bound to hemoglobin
• White blood cells (leukocytes)
– Fight infections and cancer
Centrifugedblood
sample
Cellular elements (45%)
Cell type Numberper L (mm3) of blood
Functions
Erythrocytes(red blood cells)
5–6 million Transport of oxygen (and carbon dioxide)
Leukocytes(white blood cells)
5,000–10,000 Defense andimmunity
Basophil
Eosinophil
Lymphocyte
Monocyte
Blood clotting250,000–400,000
Platelets
Neutrophil
Figure 23.13 (right part)
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Animal Respiration
Breathe?
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Respiratory Surfaces
• Gas exchange
– For all cells in the body.
• Skin
• Gills
• Tracheae (insects)
• Lungs
Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Respiratory System
• Air: mouth and nose -> pharynx -> larynx -> trachea -> bronchus -> bronchioles
• Bronchioles dead-end:
– air sacs: alveoli
• Site of gas exchange
Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Take a Breath
• inhalation (inspiration)
• Exhalation (expiration)
• Automatic
– Control centers in brain
– Respond to CO2 levels in the blood
• Conscious control?
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Hemoglobin?
• Oxygen does mix easily with blood.
• Carried in hemoglobin molecules within red blood cells
• Anemia?