Transcript Human Circulation and Respiration

Human Circulation
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Every organism must exchange materials and
energy with its environment, and this exchange
ultimately occurs at the cellular level.
Cells live in aqueous environments.
 The resources that they need, such as nutrients and
oxygen, move across the plasma membrane to the
cytoplasm.
 Metabolic wastes, such as carbon dioxide, move out
of the cell.
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Most animals have organ systems specialized
for exchanging materials with the environment,
and many have an internal transport system that
conveys fluid (blood or interstitial fluid)
throughout the body.
For aquatic organisms, structures like gills present
an expansive surface area to the outside
environment.
 Oxygen dissolved in the surrounding water diffuses
across the thin epithelium covering the gills and into
a network of tiny blood vessels (capillaries).
 At the same time, carbon dioxide diffuses out into
the water.
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Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
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Diffusion alone is not adequate for transporting
substances over long distances in animals - for example,
for moving glucose from the digestive tract and oxygen
from the lungs to the brain of mammal.
Diffusion is insufficient over distances of more than a
few millimeters.
The circulatory system solves this problem by ensuring
that no substance must diffuse very far to enter or leave a
cell.
FUNCTIONS OF VERTEBRATE CIRCULATORY SYSTEMS
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A. Nutrient and Waste Transport
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Nutrients enter blood through wall of small intestine
Carried to liver for storage or metabolism-gyycogen
Dissolved glucose and metabolites carried to all body cells
Metabolizing cells release wastes into blood
Wastes carried to kidney for removal
Constitutes metabolic circuit or systemic circulation
B. Oxygen and Carbon Dioxide Transport
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Oxygen diffuses into blood through gills or lungs
Oxygen accumulates in hemoglobin of red blood cells
Oxygen released at metabolizing cells
Carbon dioxide, a metabolic product, is released by cells into blood
Waste carbon dioxide carried back to gills or lungs and released
Constitutes respiratory circuit or pulmonary circulation
C. Temperature Regulation
1. Most vertebrates are poikilotherms, body temperature varies
with environmental temperature
2.Mammals and birds are homeotherms, maintain constant
body temperature
3.Heat distributed by circulating blood
4.Temperature adjusted by directing flow to interior or
extremities
a. Decrease body temperature by dissipating heat to
environment
b. Retain heat by directing blood from extremities to interior
D. Hormone Circulation
1. Hormones transported to target tissues throughout body
2. Hormones persist only a short time, are destroyed by body
enzymes
" A dream is not what
you see in sleep, it is the
thing that does not let
you sleep."
A. Closed system: blood enclosed within vessels
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Circulating fluid does not mix with other body fluids
Materials pass across by diffusion through walls of vessels
Annelids have a closed system
Movement of fluid in vessels assisted by muscle contraction
All vertebrates have closed circulatory system
Advantage of closed systems
• a. Can change diameter of individual muscle-encased vessels
• b. Regulate fluid flow in specific parts of body independently
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B. Open system: no distinction between circulating fluid and body
fluid
– 1. Arthropods have an open system
– 2. Muscular tube in body cavity pumps fluid through network of
channels
– 3. Fluid drains back into central cavity
Three main circuits
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Pulmonary
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Systemic
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Blood goes from heart to lungs to pick up oxygen
and release carbon dioxide
Blood pumped out of heart to the rest of the body
Coronary
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Heart muscle itself supplied with oxygen, nutrients,
etc.
Blood flow through the body
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Blood vessels
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Arteries--take oxygenated blood away from
the heart
Thick/muscular walls
 Do not contain valves
 All carry oxygen but one.
 Which one?
 PULMONARY ARTERY
 Go from large diameter to small diameter
 Become arterioles before capillaries
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Blood flow through the body
• Blood vessels
• Gases diffuse across very thin wall of
small vessels called capillaries
• Most are 1 cell thick
• Exchange CO2 for O2
• Nutrients for wastes
• Return to heart
•Blood flow through the body
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Blood vessels
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Veins--take deoxygenated blood back to the
heart
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Thin walls
Have valves
Prevents backflow
QuickTime™ and a
Where are they in greatest numbers? Photo - JPEG decompressor
are needed to see this picture.
Lower body. Why?
Gravity
• Metabolic rate is an important factor in the
evolution of cardiovascular systems. Shift
from filter feeding to active capture of prey
– In general, animals with high metabolic rates
have more complex circulatory systems and
more powerful hearts than animals with low
metabolic rates.
– Similarly, the complexity and number of blood
vessels in a particular organ are correlated
with that organ’s metabolic requirements.
ALL BLOOD
CIRCUITS
HEART EVOLUTION
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Frogs and other amphibians have a threechambered heart with two atria and one ventricle.
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1. Evolution of large veins from lungs called
pulmonary veins
a. Altered blood flow: blood from lungs
returns to heart for Repumping
2. Advantage: blood pumped to tissues
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The ventricle pumps
blood into a forked
artery that splits the
ventricle’s output into
the pulmonary
and systemic
circulations.
at higher pressure
3. Disadvantage: oxygenated blood mixed with
unoxygenated blood
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Frogs and other amphibians have a threechambered heart with two atria and one ventricle.
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1. Evolution of large veins from lungs called
pulmonary veins
a. Altered blood flow: blood from lungs
returns to heart for Repumping
2. Advantage: blood pumped to tissues
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The ventricle pumps
blood into a forked
artery that splits the
ventricle’s output into
the pulmonary
and systemic
circulations.
at higher pressure
3. Disadvantage: oxygenated blood mixed with
unoxygenated blood
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The evolution of a powerful four-chambered
heart was an essential adaptation in support of
the endothermic way of life characteristic of
birds and mammals.
Endotherms use about ten times as much energy as
ectotherms of the same size.
 Therefore, the endotherm circulatory system needs
to deliver about ten times as much fuel and O2 to
their tissues and remove ten times as much wastes
and CO2.
 Birds and mammals evolved from different reptilian
ancestors, and their powerful four-chambered hearts
evolved independently - an example of convergent
evolution.
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The closed circulatory system of humans and
other vertebrates is often called the
cardiovascular system.
 The heart consists of one atrium or two atria, the
chambers that receive blood returning to the
heart, and one or two ventricles, the chambers
that pump blood out of the heart.
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Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Structure of the Heart
 Covered with a sac called
the pericardium
 Hollow, cone-shaped
structure made of muscle
called myocardium
 4 Chamber or Cavities
 2 Atrium
 2 Ventricles
 4 Valves
 Allows blood to flow in one
direction
 Separates chambers-prevents
backflow of blood
HEART STRUCTURE
Blood flow through the heart
(heart pumping animation!)
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Into vena cava-superior or inferior
Into right atrium
Thru AV valve
Down to right ventricle
Thru pulmonary valve
Out pulmonary artery to lungs--gets 02
and dumps CO2
Back to heart through pulmonary vein
Into left atrium
Thru AV valve
Down to left ventricle
Thru aortic valve
Out aorta to body
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St. Joseph’s asp. animation
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Trace Blood Flow in the Heart
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Using Pencil trace the flow of blood
through the heart (starting in the
superior and inferior vena cava)
Shade the areas of the heart that
contain deoxygenated blood
http://www.sumanasinc.c
om/webcontent/animation
s/content/human_heart.ht
ml
Click the Link Below to Review
One More Time
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Four valves in the heart, each consisting of
flaps of connective tissue, prevent backflow and
keep blood moving in the correct direction.
Between each atrium and ventricle is an
atrioventricular (AV) valve which keeps blood
from flowing back into the atria when the ventricles
contract.
 Two sets of semilunar valves, one between the left
ventricle and the aorta and the other between the
right ventricle and the pulmonary artery, prevent
backflow from these vessels into the ventricles
while they are relaxing.
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Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
HEART SOUND AND
REGULATION
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Sound of heart (lub/dub) made by valves
closing
Lub is the AV valves closing-first sound
Dub is the Aortic and Pulmonary valves
closing-second sound
Delivery of oxygen to the body’s organs is
critical for survival.
 Certain cells of vertebrate cardiac muscle are
self-excitable, meaning they contract without any
signal from the nervous system.
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Each cell has its own built in contraction rhythm.
 However, these cells are synchronized by the
sinoatrial (SA) node, or pacemaker, which sets the
rate and timing at which all cardiac muscle cells
contract.
 The SA node is located in the wall of the right atrium.
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The cardiac cycle is regulated by electrical
impulses that radiate throughout the heart.
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Cardiac muscle cells are electrically coupled by
intercalated disks between adjacent cells.
Fig. 42.7
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
HEART BEAT REGULATION
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(1) The SA node generates electrical impulses, much
like those produced by nerves that spread rapidly (2)
through the wall of the atria, making them contract in
unison.
The impulse from the SA node is delayed by about
0.1 sec at the atrioventricular (AV) node, the relay
point to the ventricle, allowing the atria to empty
completely before the ventricles contract.
(3) Specialized muscle fibers called bundle branches
and Purkinje fibers conduct the signals to the apex of
the heart and (4) throughout the ventricular walls.
This stimulates the ventricles to contract from the
apex toward the atria, driving blood into the large
arteries.
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Contraction stimulated by membrane depolarization, reversal of
electrical polarity
Contraction triggered by SA node-pacemaker
Membrane of cells depolarize spontaneously with regular rhythm
Depolarization passes from one cardiac muscle cell to another
Spreads because cardiac cells(myocardial) are electrically
coupled by gap junctions
Ventricular wave of depolarization delayed by nearly 0.1
second
Atria and ventricles separated by connective tissue
Connective tissue cannot generate depolarization-SO
Wave passes via atrioventricular node (AV node)
Delay permits atria to completely empty before ventricles
contract
Depolarization conducted over both ventricles via bundle of
His
Transmitted by Purkinje fibers that stimulate ventricle
myocardial cells
Right and left ventricles contract almost simultaneously
ELECTRICAL CONDUCTION
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http://www.youtube.com/watch?v=zS9dEeI
HE98&feature=related
VALVE SOUNDS
http://www.bostonscientific.com/templatedata
/imports/HTML/CRM/heart/heart_valves.h
tml
Blood pressure and pulse
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Blood pressure compares diastolic and systolic
pressures
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Diastole--heart relaxes and blood flows into heart
chambers
Systole--ventricles contract, sending blood out of
heart
• http://www.bostonscientific.com/templatedata/imports/HT
ML/CRM/heart/index.html
• Heart sounds
http://www.youtube.com/watch?v=WXwYYsi6z7Q&feature
=related
• Hearts electrical system
• http://www.bostonscientific.com/templatedata/imports/HT
ML/lifebeatonline/summer2004/learning.shtml
• Blood in the closed circulatory systems of vertebrates is a
specialized connective tissue consisting of several kinds of
cells suspended in a liquid matrix called plasma.
• The plasma is about 45% of the blood volume, transparent
and straw-colored.
• 90% water
• Variety of ions, sometimes referred to as blood electrolytes
– Plasma is a dilute salt solution. Primarily sodium,
chloride and bicarbonate
– Maintain osmotic balance of the blood and help buffer the
blood.
– Proper functioning of muscles and nerves depends on
the concentrations of key ions in the interstitial fluid.
• Plasma carries a wide variety of substances in transit from
one part of the body to another, including nutrients,
metabolic wastes, respiratory gases, and hormones.
Fig. 42.14
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• The plasma proteins have many functions.
– Collectively, they acts as buffers against pH changes,
help maintain osmotic balance, and contribute to the
blood’s viscosity.
– Some specific proteins transport otherwise-insoluble
lipids in the blood.
– Other proteins, the immunoglobins or antibodies, help
combat viruses and other foreign agents that invade
the body. Liver produces most plasma proteins, including
albumin
– Alpha and beta globin proteins are carriers of lipids and steroid
hormones
– Fibrinogen proteins help plug leaks when blood
vessels are injured.
• Blood plasma with clotting factors removed is called serum.
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Red blood cells, or erythrocytes, are by far the
most numerous blood cells.
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Each cubic millimeter of blood contains 5 to 6 million red
cells, 5,000 to 10,000 white blood cells, and 250,000 to
400,000 platelets.
There are about 25 trillion red cells in the body’s 5 L of
blood.
Carry oxygen transport, depends on rapid diffusion
of oxygen across the red cell’s plasma
membranes.
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Human erythrocytes are small biconcave disks,
presenting a great surface area.
Mammalian erythrocytes lack nuclei, an unusual
characteristic that leaves more space in the tiny cells for
hemoglobin, the iron-containing protein that transports
oxygen.
Red blood cells also lack mitochondria and generate
their ATP exclusively by anaerobic metabolism.
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Contains about 250 million molecules of
hemoglobin.
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hemoglobin molecule binds up to four
molecules of O2.
 Recent research has also found that hemoglobin
also binds the gaseous molecule nitric oxide
(NO). Also CO
 As red blood cells pass through the capillary
beds of lungs, gills, or other respiratory organs,
oxygen diffuses into the erythrocytes and
hemoglobin binds O2 and NO.
 The NO relaxes the capillary walls, allowing
them to expand, helping delivery of O2 to the
cells.
RED BLOOD CELLS
 There are five major types of white blood cells, or leukocytes:
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monocytes, neutrophils, basophils, eosinophils, and
lymphocytes.
Less than 1% of total blood cells
Their collective function is to fight infection.
 White blood cells spend most of their time outside the
circulatory. Diapedesis
 system, patrolling through interstitial fluid and the
lymphatic system, fighting pathogens.
Injured cells release histamine
Dilation of arterioles increases blood flow, makes area red
 For example, monocytes and neutrophils are phagocytes,
which engulf and digest bacteria and debris from our own
cells.
 Lymphocytes develop into specialized B cells and T cells,
which produce the immune response against foreign
substances.
 Produces in the lymphatic system, bone marrow and the
thymus
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WHITE BLOOD CELLS
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The third cellular element of blood, platelets,
are fragments of cells about 2 to 3 microns in
diameter.
They have no nuclei and originate as pinched-off
cytoplasmic fragments of large cells in the bone
marrow.
 Platelets function in blood clotting.
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Erythrocytes, leukocytes, and platelets all
develop from a single population of cells,
pluripotent stem cells, in the red marrow of
bones, particularly the ribs, vertebrae,
breastbone, and pelvis.
“Pluripotent” means that these cells have the
potential to differentiate into any type of blood cells
or cells that produce platelets.
 This population renews itself while replenishing the
blood with cellular elements.
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Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 42.13
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
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A negative-feedback mechanism, sensitive to
the amount of oxygen reaching the tissues via
the blood, controls erythrocyte production.
If the tissues do not produce enough oxygen, the
kidney converts a plasma protein to a hormone
called erythropoietin, which stimulates production
of erythrocytes.
 If blood is delivering more oxygen than the tissues
can use, the level of erythropoietin is reduced, and
erythrocyte production slows.
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Recent breakthroughs in isolating and culturing
pluripotent stem cells, may soon lead to
treatments of problems such as leukemia.
Individuals with leukemia have a cancerous line of
stem cells that produce leukocytes.
 These cancerous cells crowd out cells that make red
blood cells and produce an unusually high number
of leukocytes, many of which are abnormal.
 One strategy now being used experimentally for
treating leukemia is to remove pluripotent stem
cells from a patient, destroy the bone marrow, and
restock it with noncancerous pluripotent cells.
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BLOOD CLOTTING
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Blood contains a self-sealing material that plugs
leaks from cuts and scrapes.
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A clot forms when the inactive form of the plasma
protein fibrinogen is converted to fibrin, which
collects into threads that form the framework of the
clot.
The clotting mechanism begins with the release of
clotting factors from platelets.
The clotting process begins when the endothelium of
a vessel is damaged and connective tissue in the wall
is exposed to blood.
Platelets adhere to collagen fibers and release a
substance that makes nearby platelets sticky.
The platelets form a plug.
The seal is reinforced by a clot of fibrin when vessel
damage is severe.
Fig. 42.16
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
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Anticlotting factors in the blood normally
prevent spontaneous clotting in the absence of
injury.
Sometimes, however, platelets clump and fibrin
coagulates within a blood vessel, forming a clot
called a thrombus, and blocking the flow of blood.
 These potentially dangerous clots are more likely to
form in individuals with cardiovascular disease,
diseases of the heart and blood vessels.
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Blood types
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A,B,O dictated by the antigen that is on the
surface of the RBC’s
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Antigens are substances that trigger an
immune response
A has A antigen
B has B
AB has both
O has no antigens
BLOOD TYPES
Removal of wastes
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Blood takes CO2 back to lungs
Delivers salts, water, and nitrogenous
wastes (urea) to the kidneys for excretion
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Urea
Main nitrogenous waste of body
 Produced in liver (from ammonia--NH3)
 Removed by kidneys
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