Transcript Transport Systems in Animals

What is the role of the circulatory
system?
Maintain internal homeostasis
What are some things that
would need to be balanced
within the body?
Maintain temperature, O2
conc., blood glucose, etc.
Deliver and remove nutrients and
gases to and from the body
Maintain cells in a fluid
environment that allows for these
exchanges to occur
To do all of this, the circulatory system must come into contact with
most tissues in the human body.
Which of the organisms below have transport systems?
Which do not? Explain your reasoning!
How can the paramecium and hydra thrive with no
circulatory system?
Open vs. Closed Systems
Which system seems more efficient? What are your reasons?
Open Circulatory System
Body fluid is
pumped through
open ended
vessels and
bathes organs.
Occurs in insects,
crabs, and other
animals that have
exoskeletons
Body fluid is
circulated by the
heart
How efficient is
this? Why?
Why Do Bugs Make
Such a Mess?
Closed Circulatory Systems
Blood is confined to major
vessels which branch into
smaller vessels that carry
blood to organs.
Blood is pumped through
the body by the heart.
Blood flow is faster than in
an open system
If you are a cheetah, what
type of circulatory system
would you need? Why?
Several types of blood vessels exist
in the circulatory systems of
vertebrates.
What are the three types of blood
vessels?
Arteries, capillaries, & veins
Blood Vessels
Blood Vessels
Blood travels through three types of vessels:
What are some differences you notice
between these vessels?
1. Arteries
2. Capillaries 3. Veins
Blood Vessels
Blood is carried in a closed
system of vessels that
begins and ends at the
heart
The three major types of
vessels are arteries,
capillaries, and veins
Arteries carry blood away
from the heart, veins carry
blood toward the heart
Capillaries contact tissue
cells and directly serve
cellular needs
Elastic (Conducting) Arteries
Thick-walled arteries
near the heart; the
aorta and its major
branches
Large lumen allow lowresistance conduction
of blood
Contain elastin in all
three tunics
Withstand and smooth
out large blood
pressure fluctuations
Allow blood to flow
fairly continuously
through the body
Arteries of the Head and Neck
Arteries of the Brain
Arteries of the Upper Limbs and Thorax
Arteries of the Abdomen
Arteries of the Lower Limbs
Muscular (Distributing) Arteries and
Arterioles
Muscular arteries – distal to elastic
arteries; deliver blood to body organs
Have thick tunica media with more
smooth muscle and less elastic tissue
Active in vasoconstriction
Arterioles – smallest arteries; lead to
capillary beds
Control flow into capillary beds via
vasodilation and constriction
Capillaries
Capillaries are the
smallest blood vessels
Walls consisting of a
thin tunica interna, one
cell thick
Allow only a single
RBC to pass at a time
Pericytes on the outer
surface stabilize their
walls
There are three
structural types of
capillaries: continuous,
fenestrated, and
sinusoids
Capillary Beds
A microcirculation of
interwoven networks of
capillaries, consisting of:
Vascular shunts –
metarteriole–thoroughfare
channel connecting an
arteriole directly with a
postcapillary venule
True capillaries – 10 to
100 per capillary bed,
capillaries branch off the
metarteriole and return to
the thoroughfare channel
at the distal end of the
bed
Venous System: Veins
Veins are:
Formed when venules converge
Composed of three tunics, with a thin
tunica media and a thick tunica externa
consisting of collagen fibers and elastic
networks
Capacitance vessels (blood reservoirs)
that contain 65% of the blood supply
Venous System: Veins
Veins have much lower blood pressure and thinner
walls than arteries
To return blood to the heart, veins have special
adaptations
Large-diameter lumens, which offer little resistance to
flow
Valves (resembling semilunar heart valves), which
prevent backflow of blood
Venous sinuses – specialized, flattened veins with
extremely thin walls (e.g., coronary sinus of the
heart and dural sinuses of the brain)
Factors Aiding Venous Return
What is the purpose of the valves found in veins?
Keep blood flowing toward the heart.
So what happened here?
Why must the capillary walls be so thin?
So materials can diffuse through the wall for exchange.
Veins of Systemic Circulation
Veins of the Head and Neck
Veins of the Brain
Veins of the Upper Limbs and Thorax
Veins of the Abdomen
Veins of the Pelvis and Lower Limbs
Blood Vessels - Summary
Arteries: carry blood away from the
heart, thickest walls
Veins: carry blood toward the heart,
thinner walls, one-way valves
Capillaries: extremely thin walls,
sites of exchange in lungs and
body cells
ARTHERIOSCLER
OSIS=The
narrowing of blood
vessels due to
build- up of fats
that turn into
plaque on the
artery and vein
walls.
How do these three different
circulatory systems compare?
What are systemic capillaries?
Capillaries that are located throughout the body
Circulation in Fish
How many chambers does the heart have?
-2 chambered heart
How many loops does this circulatory
system have?
1
Blood is oxygenated in gills and travels to
the body
Heart gills systemic heart
Circulation In Amphibians and Reptiles
How many chambers does the reptilian heart
have?
-3 chambered heart
How many loops does this circulatory
system have?
2 (double loop circulatory system)
Trace the blood flow through the body…
Heart lungs heart systemic
Where is the inefficiency in the amphibian
3-chambered system?
The Heart and Blood Flow in Mammals
How many chambers are there?
-4 chambered heart
How many loops?
2
Trace the blood flow through the
body…
Heart lung heart systems
How is this heart more efficient
than the reptilian heart?
Heart Animation
Heart Anatomy
The Circulatory System
Coverings of the Heart: Physiology
The pericardium:
Protects and
anchors the heart
Prevents overfilling
of the heart with
blood
Allows for the heart
to work in a
relatively frictionfree environment
Heart Wall
Epicardium – visceral layer of the
serous pericardium
Myocardium – cardiac muscle layer
forming the bulk of the heart
Fibrous skeleton of the heart –
crisscrossing, interlacing layer of
connective tissue
Endocardium – endothelial layer of
the inner myocardial surface
External Heart: Major Vessels
of the Heart (Anterior View)
Vessels returning blood to the
heart include:
Superior and inferior venae
cavae
Right and left pulmonary
veins
Vessels conveying blood
away from the heart include:
Pulmonary trunk, which splits
into right and left pulmonary
arteries
Ascending aorta (three
branches) – brachiocephalic,
left common carotid, and
subclavian arteries
External Heart: Major Vessels of the
Heart (Posterior View)
Vessels returning
blood to the heart
include:
Right and left
pulmonary veins
Superior and inferior
venae cavae
Vessels conveying
blood away from the
heart include:
Aorta
Right and left
pulmonary arteries
Gross Anatomy of Heart: Frontal Section
Atria of the Heart
Atria are the receiving chambers of
the heart
Each atrium has a protruding auricle
Pectinate muscles mark atrial walls
Blood enters right atria from superior
and inferior venae cavae and
coronary sinus
Blood enters left atria from pulmonary
veins
Ventricles of the Heart
Ventricles are the discharging
chambers of the heart
Papillary muscles and trabeculae
carneae muscles mark ventricular
walls
Right ventricle pumps blood into the
pulmonary trunk
Left ventricle pumps blood into the
aorta
Pathway of Blood Through the Heart
and Lungs
Right atrium  tricuspid valve  right
ventricle
Right ventricle  pulmonary semilunar
valve  pulmonary arteries  lungs
Lungs  pulmonary veins  left atrium
Left atrium  bicuspid valve  left
ventricle
Left ventricle  aortic semilunar valve 
aorta
Aorta  systemic circulation
Pathway of Blood Through the Heart
and Lungs
Coronary Circulation: Arterial Supply
Coronary Circulation: Venous Supply
Heart Valves
Heart valves ensure unidirectional
blood flow through the heart
Atrioventricular (AV) valves lie
between the atria and the ventricles
AV valves prevent backflow into the
atria when ventricles contract
Chordae tendineae anchor AV valves
to papillary muscles
Heart Valves
Aortic semilunar valve lies between
the left ventricle and the aorta
Pulmonary semilunar valve lies
between the right ventricle and
pulmonary trunk
Semilunar valves prevent backflow of
blood into the ventricles
Heart Valves
Heart Valves
Atrioventricular Valve Function
Semilunar Valve Function
Microscopic Anatomy of Heart Muscle
The Heart
The Mammalian Heart
The Cardiac Cycle
The heart is composed of cardiac muscle
and each beat is a muscle contraction and
relaxation
Contraction = Systolic Pressure
Relaxation = Diastolic pressure
How is blood pressure written?
Systolic / diastolic
Heart Physiology: Sequence of
Excitation
Heart Excitation Related to ECG
Extrinsic Innervation of the Heart
Heart is stimulated
by the sympathetic
cardioacceleratory
center
Heart is inhibited
by the
parasympathetic
cardioinhibitory
center
Electrocardiography
Heart Sounds
Heart sounds (lub-dup) are
associated with closing of heart
valves
First sound occurs as AV valves close
and signifies beginning of systole
Second sound occurs when SL valves
close at the beginning of ventricular
diastole
Cardiac Cycle
Cardiac cycle
refers to all events
associated with
blood flow through
the heart
Systole –
contraction of heart
muscle
Diastole –
relaxation of heart
muscle
Preload and Afterload
Regulation of Heart Rate: Autonomic
Nervous System
Sympathetic nervous system (SNS)
stimulation is activated by stress,
anxiety, excitement, or exercise
Parasympathetic nervous system
(PNS) stimulation is mediated by
acetylcholine and opposes the SNS
PNS dominates the autonomic
stimulation, slowing heart rate and
causing vagal tone
Factors Involved in Regulation of
Cardiac Output
Blood Pressure
What is blood pressure?
The force that blood exerts against vessel
walls
Is BP greater in arteries or veins?
In arteries
Find your pulse- what are you feeling here?
Pulse is measure of BP
Which would have a higher blood pressure,
constricted blood or dilated vessels?
Constricted vessels
Does the BP have an effect on veins?
No- the pressure is lost in the capillaries
How, then does blood move in veins?
What is average blood pressure?
120/80 (mm Hg) of pressure on artery
walls.
Which part of the heart contracts first?
The atria contract first, followed
immediately by the ventricles.
Systemic Blood Pressure
The pumping action of the
heart generates blood flow
through the vessels along a
pressure gradient, always
moving from higher- to lowerpressure areas
Pressure results when flow is
opposed by resistance
Systemic pressure:
Is highest in the aorta
Declines throughout the
length of the pathway
Is 0 mm Hg in the right atrium
The steepest change in blood
pressure occurs in the
arterioles
Arterial Blood Pressure
Systolic pressure – pressure exerted on
arterial walls during ventricular contraction
Diastolic pressure – lowest level of arterial
pressure during a ventricular cycle
Pulse pressure – the difference between
systolic and diastolic pressure
Mean arterial pressure (MAP) – pressure
that propels the blood to the tissues
MAP = diastolic pressure + 1/3 pulse
pressure
Blood Pressure
Cardiac Output (CO)
Volume of blood pumped/ minute
Stroke Volume (SV)
Amount of blood pumped by the left
ventricle each time it contracts (about 75
mL per beat for the average person)
75 X 70 = 5250 mL/min.
CO is affected by heart rate and SV
Alterations in Blood Pressure
Hypotension – low BP in which systolic
pressure is below 100 mm Hg
Hypertension – condition of sustained
elevated arterial pressure of 140/90 or
higher
Transient elevations are normal and can be
caused by fever, physical exertion, and
emotional upset
Chronic elevation is a major cause of heart
failure, vascular disease, renal failure, and
stroke
Hypotension
Orthostatic hypotension – temporary low
BP and dizziness when suddenly rising
from a sitting or reclining position
Chronic hypotension – hint of poor nutrition
and warning sign for Addison’s disease
Acute hypotension – important sign of
circulatory shock
Threat to patients undergoing surgery and
those in intensive care units
Hypertension
Hypertension maybe transient or persistent
Primary or essential hypertension – risk
factors in primary hypertension include
diet, obesity, age, race, heredity, stress,
and smoking
Secondary hypertension – due to
identifiable disorders, including excessive
renin secretion, arteriosclerosis, and
endocrine disorders
How Does Your Heart Beat?
Can you control the
beating of your own
heart?
No- the heart
muscles contract on
their own.
The heart has a
pacemaker, or SA
node, that maintains
the heart’s rhythm.
• The pacemaker sets the tempo of the
heartbeat.
Blood Composition continued...
Diagramatic View
Real Blood Cells
Overview of Blood Circulation
Blood leaves the heart via arteries
that branch repeatedly until they
become capillaries
Oxygen (O2) and nutrients diffuse
across capillary walls and enter
tissues
Carbon dioxide (CO2) and wastes
move from tissues into the blood
Overview of Blood Circulation
Oxygen-deficient blood leaves the
capillaries and flows in veins to the
heart
This blood flows to the lungs where it
releases CO2 and picks up O2
The oxygen-rich blood returns to the
heart
Composition of Blood
Blood is the body’s only fluid tissue
It is composed of liquid plasma and
formed elements
Formed elements include:
Erythrocytes, or red blood cells (RBCs)
Leukocytes, or white blood cells (WBCs)
Platelets
Hematocrit – the percentage of RBCs
out of the total blood volume
Blood
Blood is the Liquid Tissue
55% of blood is plasma (mostly
water) carries nutrients, wastes
and important proteins like
antibodies and clotting factors.
45% is made of cells
Red, white blood cells and
platelets
Erythrocytes (RBC)
contain hemoglobin and
carry oxygen
Leukocytes (WBC) are usually
stored in the bone marrow, and
are the body’s defense system
Platelets are pieces of white
blood cells that are in charge of
clotting
Red
blood cell
Platelet
White
blood cell
Components of Whole Blood
Physical Characteristics and Volume
Blood is a sticky, opaque fluid with a metallic taste
Color varies from scarlet (oxygen-rich) to dark red
(oxygen-poor)
The pH of blood is 7.35–7.45
Temperature is 38C, slightly higher than “normal”
body temperature
Blood accounts for approximately 8% of body
weight
Average volume of blood is 5–6 L for males, and
4–5 L for females
Distribution
Blood transports:
Oxygen from the lungs and nutrients
from the digestive tract
Metabolic wastes from cells to the lungs
and kidneys for elimination
Hormones from endocrine glands to
target organs
Regulation
Blood maintains:
Appropriate body temperature by
absorbing and distributing heat
Normal pH in body tissues using buffer
systems
Adequate fluid volume in the circulatory
system
Blood plasma contains over 100 solutes,
including:
Proteins – albumin, globulins, clotting proteins,
and others
Nonprotein nitrogenous substances – lactic
acid, urea, creatinine
Organic nutrients – glucose, carbohydrates,
amino acids
Electrolytes – sodium, potassium, calcium,
chloride, bicarbonate
Respiratory gases – oxygen and carbon dioxide
Erythrocytes (RBCs)
Biconcave discs,
anucleate, essentially no
organelles
Filled with hemoglobin
(Hb), a protein that
functions in gas transport
Contain the plasma
membrane protein spectrin
and other proteins that:
Give erythrocytes their
flexibility
Allow them to change
shape as necessary
Structure of Hemoglobin
Hemoglobin
Oxyhemoglobin – hemoglobin bound to
oxygen
Oxygen loading takes place in the lungs
Deoxyhemoglobin – hemoglobin after
oxygen diffuses into tissues (reduced Hb)
Carbaminohemoglobin – hemoglobin
bound to carbon dioxide
Carbon dioxide loading takes place in the
tissues
Production of Erythrocytes
Hematopoiesis –
blood cell formation
Hematopoiesis occurs
in the red bone
marrow of the:
Axial skeleton and
girdles
Epiphyses of the
humerus and femur
Hemocytoblasts give
rise to all formed
elements
Dietary Requirements of
Erythropoiesis
Erythropoiesis requires:
Proteins, lipids, and carbohydrates
Iron, vitamin B12, and folic acid
The body stores iron in Hb (65%), the liver,
spleen, and bone marrow
Intracellular iron is stored in protein-iron
complexes such as ferritin and hemosiderin
Circulating iron is loosely bound to the
transport protein transferrin
Fate and Destruction of Erythrocytes
The life span of an erythrocyte is
100–120 days
Old erythrocytes become rigid and
fragile, and their hemoglobin begins
to degenerate
Dying erythrocytes are engulfed by
macrophages
Heme and globin are separated and
the iron is salvaged for reuse
Fate and Destruction of Erythrocytes
Heme is degraded to a yellow pigment called
bilirubin
The liver secretes bilirubin into the intestines as
bile
The intestines metabolize it into urobilinogen
This degraded pigment leaves the body in feces,
in a pigment called stercobilin
Globin is metabolized into amino acids and is
released into the circulation
Hb released into the blood is captured by
haptoglobin and phgocytized
Life Cycle of Red Blood Cells
Erythrocyte Disorders
Anemia – blood has abnormally low
oxygen-carrying capacity
It is a symptom rather than a disease
itself
Blood oxygen levels cannot support
normal metabolism
Signs/symptoms include fatigue,
paleness, shortness of breath, and chills
Anemia: Insufficient Erythrocytes
Hemorrhagic anemia – result of acute
or chronic loss of blood
Hemolytic anemia – prematurely
ruptured erythrocytes
Aplastic anemia – destruction or
inhibition of red bone marrow
Anemia: Decreased Hemoglobin
Content
Iron-deficiency anemia results from:
A secondary result of hemorrhagic anemia
Inadequate intake of iron-containing foods
Impaired iron absorption
Pernicious anemia results from:
Deficiency of vitamin B12
Lack of intrinsic factor needed for absorption of
B12
Treatment is intramuscular injection of B12;
application of Nascobal
Anemia: Abnormal Hemoglobin
Thalassemias – absent or faulty globin
chain in hemoglobin
Erythrocytes are thin, delicate, and deficient in
hemoglobin
Sickle-cell anemia – results from a
defective gene coding for an abnormal
hemoglobin called hemoglobin S (HbS)
HbS has a single amino acid substitution in the
beta chain
This defect causes RBCs to become sickleshaped in low oxygen situations
Leukocytes (WBCs)
Leukocytes, the only blood components
that are complete cells:
Are less numerous than RBCs
Make up 1% of the total blood volume
Can leave capillaries via diapedesis
Move through tissue spaces
Leukocytosis – WBC count over 11,000 per
cubic millimeter
Normal response to bacterial or viral invasion
Granulocytes
Granulocytes – neutrophils, eosinophils,
and basophils
Contain cytoplasmic granules that stain
specifically (acidic, basic, or both) with Wright’s
stain
Are larger and usually shorter-lived than RBCs
Have lobed nuclei
Are all phagocytic cells
Neutrophils
Neutrophils have two types of
granules that:
Take up both acidic and basic dyes
Give the cytoplasm a lilac color
Contain peroxidases, hydrolytic
enzymes, and defensins (antibiotic-like
proteins)
Neutrophils are our body’s bacteria
slayers
Eosinophils
Eosinophils account for 1–4% of WBCs
Have red-staining, bilobed nuclei connected via
a broad band of nuclear material
Have red to crimson (acidophilic) large, coarse,
lysosome-like granules
Lead the body’s counterattack against parasitic
worms
Lessen the severity of allergies by
phagocytizing immune complexes
Basophils
Account for 0.5% of WBCs and:
Have U- or S-shaped nuclei with two or
three conspicuous constrictions
Are functionally similar to mast cells
Have large, purplish-black (basophilic)
granules that contain histamine
Histamine – inflammatory chemical that acts
as a vasodilator and attracts other WBCs
(antihistamines counter this effect)
Agranulocytes
Agranulocytes – lymphocytes and
monocytes:
Lack visible cytoplasmic granules
Are similar structurally, but are
functionally distinct and unrelated cell
types
Have spherical (lymphocytes) or kidneyshaped (monocytes) nuclei
Lymphocytes
Account for 25% or more of WBCs and:
Have large, dark-purple, circular nuclei with a
thin rim of blue cytoplasm
Are found mostly enmeshed in lymphoid tissue
(some circulate in the blood)
There are two types of lymphocytes: T cells
and B cells
T cells function in the immune response
B cells give rise to plasma cells, which produce
antibodies
Monocytes
Monocytes account for 4–8% of
leukocytes
They are the largest leukocytes
They have abundant pale-blue
cytoplasms
They have purple-staining, U- or kidneyshaped nuclei
They leave the circulation, enter tissue,
and differentiate into macrophages
Monocytes
Macrophages:
Are highly mobile and actively
phagocytic
Activate lymphocytes to mount an
immune response
Formation of Leukocytes
Leukocytes Disorders: Leukemias
Leukemia refers to cancerous conditions
involving white blood cells
Leukemias are named according to the
abnormal white blood cells involved
Myelocytic leukemia – involves myeloblasts
Lymphocytic leukemia – involves lymphocytes
Acute leukemia involves blast-type cells
and primarily affects children
Chronic leukemia is more prevalent in older
people
Leukemia
Immature white blood cells are found in the
bloodstream in all leukemias
Bone marrow becomes totally occupied with
cancerous leukocytes
The white blood cells produced, though numerous,
are not functional
Death is caused by internal hemorrhage and
overwhelming infections
Treatments include irradiation, antileukemic drugs,
and bone marrow transplants
Platelets
Platelets are fragments of megakaryocytes
with a blue-staining outer region and a
purple granular center
Their granules contain serotonin, Ca2+,
enzymes, ADP, and platelet-derived growth
factor (PDGF)
Platelets function in the clotting mechanism
by forming a temporary plug that helps seal
breaks in blood vessels
Platelets not involved in clotting are kept
inactive by NO and prostaglandin I2
Detailed Events of Coagulation
Hemoglobin=Is the protein attahced
to the red blood cell that carries
oxygen around the blood stream. It
gets its help from an iron molecule.
Antigens- Substances that stimulate
an immune response. They
recognize foreign objects.
ABO Blood Groups
Type A (antigen A- antibody B)
Type B(antigen B- antibody A)
Type AB(antigens A and B, anibodies
A and B)
Type O (No antigens or antibodies A
and B)
rH factor (antigen rH-Either you have
it (positive) or you don’t (negative).
ABO Blood Groups
The ABO blood groups consists of:
Two antigens (A and B) on the surface of the
RBCs
Two antibodies in the plasma (anti-A and antiB)
An individual with ABO blood may have
various types of antigens and
spontaneously preformed antibodies
Agglutinogens and their corresponding
antibodies cannot be mixed without serious
hemolytic reactions
ABO Blood Groups
Rh Blood Groups
There are eight different Rh agglutinogens, three
of which (C, D, and E) are common
Presence of the Rh agglutinogens on RBCs is
indicated as Rh+
Anti-Rh antibodies are not spontaneously formed
in Rh– individuals
However, if an Rh– individual receives Rh+ blood,
anti-Rh antibodies form
A second exposure to Rh+ blood will result in a
typical transfusion reaction
Blood Typing
When serum containing anti-A or antiB agglutinins is added to blood,
agglutination will occur between the
agglutinin and the corresponding
agglutinogens
Positive reactions indicate
agglutination
Prevention of Undesirable Clots
Substances used to prevent
undesirable clots include:
Aspirin – an antiprostaglandin that
inhibits thromboxane A2
Heparin – an anticoagulant used
clinically for pre- and postoperative
cardiac care
Warfarin – used for those prone to atrial
fibrillation
Hemostasis Disorders: Bleeding
Disorders
Thrombocytopenia – condition where the
number of circulating platelets is deficient
Patients show petechiae (small purple blotches
on the skin) due to spontaneous, widespread
hemorrhage
Caused by suppression or destruction of bone
marrow (e.g., malignancy, radiation)
Platelet counts less than 50,000/mm3 is
diagnostic for this condition
Treated with whole blood transfusions
Hemostasis Disorders: Bleeding
Disorders
Hemophilias – hereditary bleeding
disorders caused by lack of clotting factors
Hemophilia A – most common type (83% of all
cases) due to a deficiency of factor VIII
Hemophilia B – results from a deficiency of
factor IX
Hemophilia C – mild type, caused by a
deficiency of factor XI
Hemostasis Disorders
Disseminated Intravascular Coagulation
(DIC): widespread clotting in intact blood
vessels
Residual blood cannot clot
Blockage of blood flow and severe
bleeding follows
Most common as:
A complication of pregnancy
A result of septicemia or incompatible blood
transfusions
RBC
formation
animation
Blood clotting animation
Fun Facts
•There are almost 60,000 miles of
blood vessels in the human body.
•Red blood cells are formed at the rate
of 2 million per second.
•Within a tiny droplet of blood, there
are 5 million red blood cells, 300,000
platelets and 10,000 white cells.
•It takes about 1 minute for a red blood
cell to circle the whole body.