Transcript blood

Circulation
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
Figure 42.6
Capillaries of
head and forelimbs
Superior vena cava
Pulmonary
artery
Capillaries
of right lung
Pulmonary
vein
Right atrium
Right ventricle
Pulmonary
artery
Aorta
Capillaries
of left lung
Pulmonary vein
Left atrium
Left ventricle
Aorta
Inferior
vena cava
Capillaries of
abdominal organs
and hind limbs
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
(b) A closed circulatory system
Heart
Heart
Interstitial fluid
Hemolymph in sinuses
surrounding organs
Pores
Blood
Small branch
vessels in
each organ
Dorsal
Auxiliary
vessel
hearts
(main heart)
Tubular heart
Ventral vessels
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
Cellular elements 45%
Plasma 55%
Constituent
Water
Solvent for
carrying other
substances
Ions (blood
electrolytes)
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Osmotic balance,
pH buffering,
and regulation
of membrane
permeability
Plasma proteins
Albumin
Fibrinogen
Leukocytes (white blood cells)
Separated
blood
elements
5,000–10,000
Functions
Defense and
immunity
Lymphocytes
Basophils
Eosinophils
Neutrophils
Osmotic balance,
pH buffering
Monocytes
Platelets
250,000–400,000
Clotting
Immunoglobulins Defense
(antibodies)
Substances transported by blood
Nutrients
Waste products
Respiratory gases
Hormones
Number per L
(mm3) of blood
Cell type
Major functions
Erythrocytes (red blood cells)
5–6 million
Blood
clotting
Transport
of O2 and
some CO2
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."
Circulation
• Blood moves from regions of higher pressure
to regions of lower pressure
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
Figure 42.6
Capillaries of
head and forelimbs
Superior vena cava
Pulmonary
artery
Capillaries
of right lung
Pulmonary
vein
Right atrium
Right ventricle
Pulmonary
artery
Aorta
Capillaries
of left lung
Pulmonary vein
Left atrium
Left ventricle
Aorta
Inferior
vena cava
Capillaries of
abdominal organs
and hind limbs
Figure 42.10
Vein
LM
Artery
Red blood cells
100 m
Valve
Basal lamina
Endothelium
Smooth
muscle
Connective
tissue
Endothelium
Capillary
Smooth
muscle
Connective
tissue
Artery
Vein
Capillary
15 m
Red blood cell
Venule
LM
Arteriole
Velocity
(cm/sec)
5,000
4,000
3,000
2,000
1,000
0
50
40
30
20
10
0
Pressure
(mm Hg)
Area (cm2)
Figure 42.11
120
100
80
60
40
20
0
Systolic
pressure
Diastolic
pressure
Figure 42.15
INTERSTITIAL
FLUID
Net fluid movement out
Body cell
Blood
pressure
Osmotic
pressure
Arterial end
of capillary
Direction of blood flow
Venous end
of capillary
• 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
AP standard:
• Fish, amphibians, and mammal circulatory
systems: support common ancestry
Figure 42.4
(a) Single circulation
(b) Double circulation
Pulmonary circuit
Gill
capillaries
Lung
capillaries
Artery
Heart:
A
Atrium (A)
V
Right
Ventricle (V)
A
V
Left
Vein
Systemic
capillaries
Body
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Figure 42.5a
Amphibians
Pulmocutaneous circuit
Lung
and skin
capillaries
Atrium
(A)
Atrium
(A)
Right
Left
Ventricle (V)
Systemic
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Figure 42.5b
Reptiles (Except Birds)
Pulmonary circuit
Lung
capillaries
Right
systemic
aorta
Atrium
(A)
Ventricle
(V)
A
Right
V
Left
Left
systemic
aorta
Incomplete
septum
Systemic
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-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!!)
Thermoregulation: countercurrent
exchange mechanism = common
ancestry
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
Figure 40.16
Figure 40.14
Figure 40.15