circulation. did you know? in one day, blood travels 12,000 miles. a capillary is just wide enough...
TRANSCRIPT
Did you know?
• In one day, blood travels 12,000 miles.• A capillary is just wide enough for cells to pass
through single file.• No blood flows through cartilage. This makes
cartilage slow to heal.• Grab a tennis ball and squeeze it tightly –
that’s how hard the human heart works.
Did you know?
• Bones of the rib cage are a major supplier of the body’s red blood cells.
• Adults have about 4 to 5 quarts of blood in circulation.
• A red blood cell makes approximately 250,000 trips around the circulatory system before dying
Did you know?
• Anger and fear increase the heart rate by about 30 to 40 beats per minute
• Individual heart muscle fibers grown in a cell culture beat spontaneously.
• All the blood vessels, laid end to end would measure 60,000 miles.
Do the math…
• Your heart beats about 100,000 times per day– 35 million times per year– Almost 3 billion times in an average lifespan
Did you know?
• Heart pumps blood through the aorta at about 1 mile per hour.
• The average blood temperature is 100.4oF• Blood leaving the lungs is bright red, blood
returning to the heart is dark maroon.• During exercise, more blood than usual flows
to skeletal muscles and less to the gut
Did you know?
• People giving CPR should focus on chest compressions; organs can live for several minutes on oxygen already in the blood.
• Fetal blood never carries sickle-cell anemia.• Heart disorders account for four out of five
hospitalizations in the elderly.• Heart patients have regrown healthy heart
tissue from their own stem cells.
Did you know?
• HUMAN BLOOD IS NEVER BLUE. – Does change color as it circulates– Veins look blue because the overlying tissues filter
out red light at that dedpth
Three basic jobs:
• Transportation– Oxygen, nutrients, hormones, waste products
• Protection– Immune cells, platelets, clotting agents
• Cooling– Disperses heat around the body
Superior vena cava
Pulmonaryartery
Capillariesof right lung
Pulmonaryvein
Aorta
Inferiorvena cava
Right ventricle
Capillaries ofabdominal organsand hind limbs
Right atrium
Aorta
Left ventricle
Left atrium
Pulmonary vein
Pulmonaryartery
Capillariesof left lung
Capillaries ofhead and forelimbs
Figure 42.6
Heart: central engine
• Left side pumps blood to all parts of the body except lungs– Oxygen rich blood from lungs
• Right side supplies lungs only– Collects oxygen-poor blood from blood and pumps
it to lungs for oxygenation
• Two closed networks of blood vessels
Figure 42.3
(a) An open circulatory system
Heart
Hemolymph in sinusessurrounding organs
Pores
Tubular heart
Dorsalvessel
(main heart)
Auxiliaryhearts
Small branchvessels ineach organ
Ventral vessels
Blood
Interstitial fluid
Heart
(b) A closed circulatory system
Open and Closed Circulatory Systems
• In insects, other arthropods, and most molluscs, blood bathes the organs directly in an open circulatory system
• In an open circulatory system, there is no distinction between blood and interstitial fluid, and this general body fluid is called hemolymph
© 2011 Pearson Education, Inc.
• In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid
• Closed systems are more efficient at transporting circulatory fluids to tissues and cells
• Annelids, cephalopods, and vertebrates have closed circulatory systems
© 2011 Pearson Education, Inc.
Back to mammalian circulatory system
• Largest blood vessels are arteries: carry blood away from heart
• Arteries branch out into arterioles, which lead to capillaries
• Capillaries: site of oxygen and nutrient exchange, tiniest pathways
• Capillaries merge into venules, which connect to larger veins
• Carry blood back to the heart
• Takes about one minute for each blood cell to make a circuit of the body.
Deep vein thrombosis
• Side effect of immobility• Caused by blood flowing slowly or pooling in deep
veins in lower legs or thighs• Unable to wash away clotting factors = blood clot
(thrombus) can form – blocks circulation• Limb becomes tender, swollen, hot, red• Clot can break away and travel to brain (cause stroke)
or to lung, heart, or other areas• Anticoagulants, compression stockings, periodic
breaks to stand up and get blood moving
Blood
• Connective tissue• Red blood cells, white blood cells, platelets• Cells float in a liquid (plasma)• Plasma: mostly water, includes nutrients,
hormones, gases, and other substances = 55% of bloodstream
Figure 42.17
Plasma 55%
Constituent Major functions
Water
Ions (bloodelectrolytes)SodiumPotassiumCalciumMagnesiumChlorideBicarbonate
Solvent forcarrying othersubstances
Osmotic balance,pH buffering,and regulationof membranepermeability
Plasma proteinsOsmotic balance,pH buffering
Albumin
Fibrinogen
Immunoglobulins(antibodies)
Clotting
Defense
Substances transported by blood
NutrientsWaste productsRespiratory gasesHormones
Separatedbloodelements
Basophils
Neutrophils Monocytes
Lymphocytes
Eosinophils
Platelets
Erythrocytes (red blood cells) 5–6 million
250,000–400,000 Bloodclotting
Transportof O2 and
some CO2
Defense andimmunity
FunctionsNumber per L(mm3) of blood
Cell type
Cellular elements 45%
Leukocytes (white blood cells) 5,000–10,000
Red Blood Cells
• Carry respiratory gases to and from the body’s tissues.
• Hemoglobin molecules within RBC = red pigment
• Lack a nucleus• Last only about 120 days• Die at a rate of 2 million per second• Produced in bone marrow
Heart
• 4 chambers• Size of a large fist• Weighs about 8 ounces in women and 10
ounces in adults• 2 atria (entry hall)
– Separated by thin wall called interatrial septum– Collecting room for returning blood– Pump through valves to ventricles
Heart continued
• 2 ventricles (little belly)– More muscular– Pump blood out of the heart– Separated by interventricular septum
Pacemaker
• Heart’s electrical signal begins in the sinoatrial node – heart’s natural pacemaker, located near top right atrium
• Made up of autorhythmic fibers – specialized heart cells that take in and expel calcium and other electrolytes to regularly change electrical charge
• Electrical impulse produced by cells of the SA node spread through walls of the atria by moving one cardiac cell to the next via gap junctions
• Signal makes muscle cells of atria contract in a sequenced fashion – presses blood into the ventricles
• The pacemaker is regulated by two portions of the nervous system: the sympathetic and parasympathetic divisions
• The sympathetic division speeds up the pacemaker• The parasympathetic division slows down the
pacemaker• The pacemaker is also regulated by hormones and
temperature
© 2011 Pearson Education, Inc.
Shoveling snow = deadly risks• ".... that when healthy young men shoveled snow, their heart rate and blood
pressure increased more than when they exercised on a treadmill. "Combine this with cold air, which causes arteries to constrict and decrease blood supply, you have a perfect storm for a heart attack," Dr. Barry Franklin, director of cardiac rehab at Beaumont Hospital says.
• "Shoveling snow raises blood pressure and heart rate more than some other forms of exercise cold air constricts blood vessels, cardiac risks are higher in early morning, rare exercise for sedentary over-55s.Snow shoveling is particularly strenuous because it uses arm work, which is more taxing than leg work. Straining to move wet and heavy snow is particularly likely to cause a surge in heart rate and blood pressure, Franklin says.
• Many people hold their breath during the hard work, which also puts a strain on the body. In addition, the prime time for snow clearance is between 6am and 10am which is when circadian fluctuations make us more vulnerable to heart attacks."
One heart beat = one cardiac cyle
• Oxygen-poor blood enters the right atrium• Pumped to right ventricle• Pumped through pulmonary artery to lung• Returns via pulmonary vein to left atrium• Enters left ventricle• Exits to the body via aorta
• Lasts about 0.8 seconds, pumps about 2 ounces (70 ml) of blood out of each ventricle
Superior vena cava
Pulmonaryartery
Capillariesof right lung
Pulmonaryvein
Aorta
Inferiorvena cava
Right ventricle
Capillaries ofabdominal organsand hind limbs
Right atrium
Aorta
Left ventricle
Left atrium
Pulmonary vein
Pulmonaryartery
Capillariesof left lung
Capillaries ofhead and forelimbs
Figure 42.6
Figure 42.10 Artery
Red blood cells
Endothelium
Artery
Smoothmuscle
Connectivetissue
Capillary
Valve
Vein
Vein
Basal lamina
Endothelium
Smoothmuscle
Connectivetissue
100 m
LM
Venule
15
mL
M
Arteriole
Red blood cell
Capillary
Figure 42.11
Aorta
Arterie
sArte
riole
s
Capill
arie
sVen
ules
Veins
Venae
cava
e
Systolicpressure
Diastolicpressure
020406080
100120
01020304050
Pre
ss
ure
(mm
Hg
)V
elo
cit
y(c
m/s
ec
)A
rea
(c
m2)
01,0002,0003,0004,0005,000
Figure 42.15
INTERSTITIALFLUID Net fluid movement out
Bloodpressure
Osmoticpressure
Arterial endof capillary Direction of blood flow
Venous endof capillary
Body cell
• Electrocardiogram (EKG): measures heart’s electrical conduction system
• Defibrillators restore normal rhythms to a stuttering heart
Blood maintenace
• Kidney: remove toxins and waste, maintain pH, regulate salt and water levels, maintain blood pressure
Stem Cells and the Replacement of Cellular Elements
• The cellular elements of blood wear out and are being replaced constantly
• Erythrocytes, leukocytes, and platelets all develop from a common source of stem cells in the red marrow of bones, especially ribs, vertebrae, sternum, and pelvis
• The hormone erythropoietin (EPO) stimulates erythrocyte production when O2 delivery is low = blood doping
© 2011 Pearson Education, Inc.
AP standard:
• Signal transduction pathways coordinate activities within individual cells that support the function of the organism as a whole.
– EPO hormone: more RBCs when low O2 levels
Signaling examples:
• Fight or flight response– Constriction of arteries: raise blood pressure– Dilation of arteries at muscles: delivers more
blood– Quickened heart beat and respiration– Rise in blood sugar– Suppresses immune system– Divert blood flow from other parts of body to
muscles
Figure 42.4
(a) Single circulation (b) Double circulation
Artery
Heart:
Atrium (A)
Ventricle (V)
Vein
Gillcapillaries
Bodycapillaries
Key
Oxygen-rich blood
Oxygen-poor blood
Systemic circuit
Systemiccapillaries
Right Left
A A
VV
Lungcapillaries
Pulmonary circuit
Amphibians
Pulmocutaneous circuit
Lungand skincapillaries
Atrium(A)
Atrium(A)
LeftRight
Ventricle (V)
Systemiccapillaries
Systemic circuit
Key
Oxygen-rich bloodOxygen-poor blood
Figure 42.5a
Figure 42.5b
Reptiles (Except Birds)
Pulmonary circuit
Systemic circuit
Systemiccapillaries
Incompleteseptum
Leftsystemicaorta
LeftRight
Rightsystemicaorta
A
V
Lungcapillaries
Atrium(A)
Ventricle(V)
Key
Oxygen-rich bloodOxygen-poor blood
Mammals and Birds
• Mammals and birds have a four-chambered heart with two atria and two ventricles
• The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood
• Mammals and birds are endotherms and require more O2 than ectotherms
© 2011 Pearson Education, Inc.
AP Standard: thermoregulation
• Ability of an organism to keep its body temperature within certain boundaries.– Ectotherms/thermoconformers: gain heat from
environment– Endotherms/thermoregulators: use internal
control mechanisms to moderate internal environment (heat: metabolism) = calorie expensive!
Advantages to endothermy:
• Perform vigorous activities (running/flight) longer than ectotherms
• Can withstand more severe environmental fluctuations of terrestrial environment (aquatic habitats tend to be stable – WATER PROPERTY!!)
Other ways to control temps…
• Behavior (radiation, convection and conduction)
• Sweating (vaporization)• Goosebumps: hair/feather raising to gather
air: thermal insulation!• BLUBBER• shivering• Hibernation, estivation