Transcript Chapter 42 Circulatory System

Circulatory System
Chapter 42
A. P. Biology
Liberty Senior High
Mr. Knowles
What’s the purpose of the
cardiovascular system?
Do all organisms have one?
Unicellular Organisms
• Use simple diffusion for moving
nutrients and oxygen into cell;
wastes and carbon dioxide out of
cell.
• Problem: Surface area – to –
volume ratio; limits the size.
Phylum Nemotoda
• Use a body cavity – to transport
materials to more distant cells.
• Not a true circulatory system.
• Problem: limited by size of
organism or distance cells can be
from body cavity.
Open and Closed Circulatory
Systems
• More complex animals
–Have one of two types of circulatory
systems: open or closed
• Both of these types of systems have
three basic components
–A circulatory fluid (blood)
–A set of tubes (blood vessels)
–A muscular pump (the heart)
• In insects, other arthropods, and most
molluscs:
– Blood bathes the organs directly in an
open circulatory system
Heart
Hemolymph in sinuses
surrounding ograns
Anterior
vessel
Figure 42.3a
Lateral
vessels
Ostia
Tubular heart
(a) An open circulatory system
Two Types of Circulatory
Systems
• Open Circulatory System- no
distinct circulating fluid, body fluid
is the circulating fluid.
• Muscular pump pushes fluid through
channels and spaces in body. Fluid
drains back into central cavity.
• Arthropods (Insects, Crustaceans)
• In a closed circulatory system:
– Blood is confined to vessels and is
distinct from the interstitial fluid
Heart
Interstitial
fluid
Small branch vessels
in each organ
Dorsal vessel
(main heart)
Auxiliary hearts
Figure 42.3b
Ventral vessels
(b) A closed circulatory system
Two Types of Circulatory
Systems
• Closed Circulatory Systemcirculating fluid is enclosed within
blood vessels; does not mix with other
body fluids.
• Materials diffuse through vessel walls
to tissues.
• Examples: Annelids and all
vertebrates.
Pulmonary
Circuit
Systemic
Circuit
Two Major Circuits
• Pulmonary Circuit: carries
blood to & from the gas
exchange surfaces of the lungs.
• Systemic Circuit: which
transports blood to & from the
rest of the body.
Why we need a cardiovascular
system!
• Human embryos before 3 weeks are so
small, materials are transported by simple
diffusion.
• At third week (few mms in length), heart
begins beating- first organ system to
function.
• Supplies nutrients to all 75 trillion cells in
the body.
Evolution of Vertebrate
Heart
Recall what the human
heart looks like.
Why a heart?
• More active lifestyle: change
from filter- feeding to active
prey capture; requires more
efficient respiration and
circulation.
• Invasion of land: change in
respiration system and
endothermy.
Early Chordates
• Heart = simple tube heart;
thicker muscular artery that
contracted.
• Was a peristaltic pump.
• Problem: blood is pushed in
both directions; inefficient.
• Ex. Lancelets.
Fish Heart
• True chambered-pump heart.
• A tube with four consecutive chambers.
– Sinus venosus- collects blood from body.
– Atrium- receives blood from the S.V.
– Ventricle- pumping chamber.
– Conus arteriosus- smaller, elongated
pump.
• “Two-chambered” heart in peristaltic
sequence; 1 atrium, 1 ventricle.
• Fig. 46.36
Fishes
• A fish heart has two main chambers
– One ventricle and one atrium.
• Blood pumped from the ventricle
– Travels to the gills, where it picks up
O2 and disposes of CO2
Fish Heart
• Blood goes from Heart  Gills 
Becomes Oxygenated  Arteries to
Body Tissues  Veins Return to Heart
• Benefit: peripheral tissues receive
fully oxygenated blood directly from
gills.
• Problem: blood loses pressure from
gills to body; no pulmonary
circulation.
Amphibian Heart
• Fully terrestrial lungs require a
pulmonary circuit.
• Uses pulmonary arteries/veins to
oxygenate blood and return to heart for
repumping.
• Higher pressure out to peripheral
tissues.
• “Three-chambered” heart; 2 Atria, 1
ventricle.
Amphibians
• Frogs and other amphibians:
– Have a three-chambered heart, with two
atria and one ventricle.
• The ventricle pumps blood into a forked
artery.
– That splits the ventricle’s output into the
pulmocutaneous circuit and the systemic
circuit.
Amphibian Heart
• Problem: Oxygenated and
deoxygenated blood mix in
ventricle.
• Heart pumps out a mixture of
oxy- and deoxygenated blood
to peripheral tissues.
• Inefficient systemic circulation.
Reptile Heart
• Developed a partial septum (wall)
between the ventricle.
• Partially separates oxy- and
deoxygenated blood.
• Benefit: More efficient circulation;
more active.
• Problem: Still a three-chambered
heart with some mixing; incomplete
separation.
Reptiles (Except Crocodilians)
• Reptiles have double circulation:
– With a pulmonary circuit (lungs) and a
systemic circuit.
• Turtles, snakes, and lizards:
– Have a three-chambered heart
Enter the Crocodiles!
• Have complete separation of
ventricles.
• First Four-chambered heart that
separates oxy- and deoxygenated
blood.
• Completely separate pulmonary and
systemic circuits.
• Increased efficiency and more active.
A Very Active Saltwater Crocodile!
Mammal and Bird Hearts
• True Four-chambered hearts- separate
systemic and pulmonary circuits.
• Can repump blood to body after return
from lungs without mixing oxy- and
deoxygenated blood.
• Double Pump: Right side = pulmonary
circuit and Left Side = systemic circuit.
• Greater efficiency = higher metabolic rate,
transport of heat and endothermy.
• The mammalian cardiovascular system
7
Capillaries of
head and
forelimbs
Anterior
vena cava
Pulmonary
artery
9
6
Capillaries
of right lung
2
3
Pulmonary
vein
Right atrium
Pulmonary
artery
Aorta
Capillaries
of left lung
4
3
11
5
1
Pulmonary
Left atrium vein
10
Left ventricle
Right ventricle
Aorta
Posterior
vena cava
8
Figure 42.5
Capillaries of
abdominal organs
and hind limbs
The Mammalian Heart: A Closer Look
Pulmonary artery
Aorta
Pulmonary
artery
Anterior vena cava
Left
atrium
Right atrium
Pulmonary
veins
Pulmonary
veins
Semilunar
valve
Semilunar
valve
Atrioventricular
valve
Atrioventricular
valve
Posterior
vena cava
Figure 42.6
Right ventricle
Left ventricle
• Vertebrate circulatory systems
AMPHIBIANS
REPTILES (EXCEPT CROCS)
MAMMALS AND BIRDS
Lung and skin capillaries
Lung capillaries
Lung capillaries
FISHES
Gill capillaries
Artery
Right
systemic
aorta
Pulmocutaneous
circuit
Gill
circulation
Pulmonary
circuit
Heart:
ventricle (V)
Atrium (A)
A
A
A
V
Right
V
Left
Right
Systemic
circulation
Vein
Systemic
circuit
Systemic capillaries
Systemic capillaries
Pulmonary
circuit
A Left
Systemic
V aorta
Left
A
A
V
Right
V
Left
Systemic
circuit
Figure 42.4
Systemic capillaries
Systemic capillaries
What is the cardiovascular
system?
Three parts:
• Blood – a circulating fluid.
• Heart – a pump.
• Blood vessels – the
conducting pipes.
Cardiovascular Lymphatic
Systems
• Fluid leaves the vessel and enters the
•
•
•
•
tissues- interstitial fluid.
Eventually returns to the vessels.
Lymphatic system has its own vessels.
Used to transport antibodies, white
blood cells, and monitor for infection and
cancer.
Cardiovascular + Lymphatic =
Circulatory System.
• The velocity of blood flow varies in the circulatory
system:
Systolic
pressure
Veins
Venules
Venae cavae
Figure 42.11
Capillaries
Diastolic
pressure
Arterioles
120
100
80
60
40
20
0
Arteries
Velocity (cm/sec)
50
40
30
20
10
0
Aorta
Area (cm2)
5,000
4,000
3,000
2,000
1,000
0
Pressure (mm Hg)
– And is slowest in the capillary beds as a result of the high
resistance and large total cross-sectional area.
• Two mechanisms:
–Regulate the distribution of blood in
capillary beds.
• In one mechanism–Contraction of the smooth muscle
layer in the wall of an arteriole
constricts the vessel.
• In a second mechanism:
– Precapillary sphincters control the flow of blood
between arterioles and venules.
Precapillary sphincters
(a) Sphincters relaxed
(b) Sphincters contracted
Arteriole
Arteriole
Thoroughfare
channel
Venule
Capillaries
Venule
(c) Capillaries and larger vessels (SEM)
Figure 42.13 a–c
20 m
Marine Mammals
• Limit heat loss by countercurrent
flow- veins run parallel to an
artery and carry heat back to core
before arterial blood circulates to
body’s surface.
• Walruses, seals, killer whales (Fig.
46.23)
What is blood?
• Specialized connective
tissue with cells in a fluid
matrix.
Functions of the Blood
• Transport dissolved gases, nutrients,
hormones, and metabolic wastes.
• Regulation of the pH and
electrolytes of interstitial fluid.
Neutralizes the acids created by
metabolism (lactic acid).
• Restricts fluid losses through
damaged vessels or at injury sitesblood clots.
Functions of the Blood
• Defense against toxins and pathogenstransports white blood cells that migrate
into tissue to fight infection and remove
debris. Also, deliver antibodies.
• Stabilize body temperature- absorbs
heat from active muscles and distributes
to other tissues. Also brings heat to the
surface of the skin to lose heat.
Composition of Blood
• It is a fluid connective tissue
with an extracellular matrixplasma + formed elements
(cells and cell fragments) =
whole blood.
• Plasma + Formed Elements =
Whole Blood.
Whole Blood After Centrifugation
Plasma
Red Blood
Cells
White Blood
Cells “Buffy
Coat”
Whole Blood
37-54%
46-63%
Centrifuge
and
Separate
Formed Elements
Plasma
Plasma
7 % Plasma
Proteins
1 % Electrolytes
and other Solutes
92 % Water
Plasma- The Fluid of Life!
• Plasma = Plasma Proteins + a Ground
Substance (Serum).
• Plasma Proteins:
Albumin- transport fatty acids,
maintain isotonic solution.
Globulin- immunoglobulin
(antibodies).
Fibrinogen- form blood clots; becomes
fibrin- an insoluble protein.
Plasma
Globulin
Serum
Albumin
Fibrinogen
Plasma- The Fluid of Life!
• Plasma that has been
allowed to clot will lose
its fibrin and other salts
+2
like Ca .
• Plasma without its fibrin
– Serum.
Formed Elements
• Formed Elements = Blood Cells + Fragments
suspended in the plasma.
• Erythrocytes (Red Blood Cells) – most
abundant (99.9% of all cells); transport of
oxygen and carbon dioxide.
• Leukocytes (White Blood Cells) – body’s
defense cells. (0.1% of cells).
• Thrombocytes (Platelets) – small, membranebound packets of cytoplasm that contain
enzymes for blood clot formation.
Erythrocyte
A Normal Blood Smear
Collecting and Analysis of Blood
• Blood usually collected at a veinvenipuncture.
• Venipuncture- veins are easy to locate,
walls of vein are thinner, pressure is
lower heals easier.
• Peripheral capillaries- tip of finger,
earlobe; oozing small drop for blood
smear.
• Arterial Puncture- check for efficiency
of gas exchange.
Properties of Blood
• Temperature- 38° C or 100.4°F.
• Viscosity- has a great deal of
dissolved proteins in plasma 
more viscous than water.
• pH – 7.35-7.45; slightly alkaline.
Erythrocytes (RBCs)
• “erythros”- red; “cyte”- cell.
• RBCs are the most abundant blood
cell (99.9%). 25 trillion in average
adult. Takes ~ 1 min. to travel circuit.
• Hematocrit- percentage of formed
elements in a sample of whole blood. #
of cells / microliter of whole blood.
• Has a red pigment-hemoglobin- gives
whole blood its color.
RBCs Structure and Function
• Highly specialized cell to transport
gases.
• Cell structure is a biconcave disc.
EM of RBCs
RBCs Structure and Function
• Shape provides the RBC with a large
surface area.
• Exchange of O2 with the surrounding
plasma must be quick; larger surface
area faster the exchange.
• Total surface of all RBCs is 3800 m2
2
compared to 1.9 m of the whole
human body.
RBCs Structure and Function
• Biconcave shape allows them to form
stacks (dinner plates) – rouleaux inside
narrow blood vessels.
• Rouleaux permit the cells to pass
through blood vessels without bumping
along the walls.
• Do not form logjams or clogs in the
narrow capillary.
Rouleaux in a Blood Smear
Rouleaux in Bone Marrow
RBCs Structure and Function
• Biconcave shape allows the
RBCs to bend and flex when
entering capillaries.
• May pass through capillaries ½
the RBC’s diameter.
RBC’s are Highly Specialized
Cells
• Have lost all organelles- lack nuclei,
mitochondria, and ribosomes.
• Lost these structures to allow more space for
hemoglobin and oxygen transport.
• Downside: RBCs unable to divide or repair
themselves. Made in bone marrow.
• Short lifespan- 120 days and then must be
broken down.
Hemoglobin (Hb)
• Accounts for 95% of proteins
inside the RBC.
• 280 million Hbs in each
RBC.
• Hb binds to and transports
O2 and CO2.
Hb Molecule
• Each Hb molecule = four protein chains
= 2 alpha chains + 2 beta chains of
polypeptides.
• Each chain is a globular subunit and has
a heme group.
• Heme – a porphyrin which is a ring
compound with an iron in the center.
• Iron has a + charge and can bind to O2
(negative).
Hb Molecule
• When hemoglobin binds to O2 – it
becomes oxyhemoglobin.
• Very weak interaction; easy to
separate.
• Fetus uses a fetal hemoglobin- more
readily binds to O2 for more efficient
uptake from mother’s RBCs.
Hb Molecule
• Alpha and Beta chains bind to CO2
at other sites and transport to
lungs.
• If hematocrit is low or the
amount of Hb in RBCs is low
than normal activity cannot be
sustained in tissue- anemia.
Sickle Cell Anemia
• Mutations in the beta chains of the Hb
molecule.
• When the blood contains abundant O2, the
Hb and RBCs are normal.
• But when the defective Hb loses its O2,
neighboring Hb molecules interact and
change the shape of the cell- curved and
stiff.
• Cannot form rouleaux and may form
clots.
Sickle
Cell
Mutation
Sickle
Cell
Mutation
Sickle Cell Anemia
Iron-Deficiency Anemia
Malaria in an RBC
Leukocytes (WBCs)
• General Properties:
1. Help defend against pathogens,
toxins, and damaged cells.
2. They have nuclei and other
organelles.
3. Are made in bone marrow,
thymus, spleen, and other lymphatic
tissue.
Two Major Groups of WBCs
1. Granulocytes- WBCs with
darkly-staining vesicles and
lysosomes inside.
a. Neutrophils
b. Eosinophils
c. Basophils
Two Major Groups of WBCs
2. Agranulocytes- do not stain
darkly on their interior; have
very small vesicles and
lysosomes.
a. Monocytes
b. Lymphocytes
Leukocytes
• Most WBCs are not in the
circulatory system, but in tissues
or organs of the lymphatic
system.
• Circulate for only a short time in
vessels.
Characteristics of WBCs
• Move along the capillaries by amoeboid
movement.
• Detect chemicals from injured cells.
• Leave the capillary by squeezing through
cells –diapedesis.
• Are positively chemotactic in the tissue.
• Can destroy things by phagocytosis.
Ameboid Movement and
Phagocytosis
Infected Cell
White Blood Cell
Diapedesis
Neutrophils
• Most abundant of WBCs.
• Granules are neutral. Filled with
toxins.
• Have a dense, segmented nucleus of
2 to 5 lobes- Polymorphonuclear
(PMNs).
• Very mobile and arrive at site of
infection first.
Neutrophils
• Phagocytize “tagged” bacteria.
• Breakdown bacteria with their
toxic granules.
• Also, release chemicals to call
WBCs to the site- interleukins.
Neutrophils
Eosinophiles
•
•
•
•
•
Granules stain with eosin- a red dye.
Only amount 2-4 % of the WBCs.
Have a bilobed nucleus.
Phagocytize bacteria and cell debris.
Use exocytosis to release toxins onto the
surface of large parasites.
• Release chemicals that cause allergic
reactions.
Eosinophil
Neutrophil and Eosinophil
Basophiles
• Stain very darkly. Very small cells.
• Very rare in circulation. Usually in tissue.
• Release granules of histamine and
heparin.
• Histamine = permeability of capillaries.
• Heparin = blood clotting.
• Do not phagocytize.
Basophil
The Last Type of Phil
How’s
that
blood
working
for you?
Monocytes
• Larger cells with oval nuclei.
• Circulate throughout the blood stream.
• Leave the vessel and become
macrophages.
• Macrophages phagocytize bacteria, cell
debris, and other foreign elements.
• Also, release chemical messengers.
Monocyte
Lymphocytes
• Larger than RBCs and lack deeplystained granules. Single, large
nucleus.
• Abundant in blood. Migrate from
blood  to tissue through
lymph return to blood.
• Most are not found in blood at any
one time.
Lymphocyte
3 Kinds of Lymphocytes
• T Cells: cellular immunity against foreign
tissue and cells infected with viruses;
have killer T cells and helper T cells (CD4 and CD-8).
• B cells: humoral immunity, produce
antibodies (globulin proteins).Also
memory cells.
• NK cells: (Natural Killers) large granules
of toxin that destroy cancerous cells and
some virally-infected cells.
Leukemia
Platelets
• Called thrombocytes in
nonmammals.
• Circulate for 9-12 days.
• Platelets are only cell
fragments in mammals.
Platelet Function
• Transport of proteins and
enzymes important to the
clotting process.
Platelet Function
• Active contraction after clot
formation has occurred.
• Contain actin & myosin.
• After clot forms contraction shrinks
clot & reduces size of break in
vessel wall
Platelet Function
• Formation of a temporary
patch in the walls of damaged
blood vessels.
–Forms a platelet plug: slows
the rate of blood loss while
clotting continues.
Blood Clot
Platelet Production
• Thrombocytopoiesis occurs
in the bone marrow.
• Bone marrow contains:
Megakaryocytes: enormous
w/ large nuclei.
Platelet Production
• Megakaryocytes make proteins,
enzymes, & membranes.
• Shed cytoplasm in small membraneenclosed packets: Platelets that enter
circulation.
• Mature megakaryocyte produces 4000
platelets.
Megakaryocyte
What happens when we
have an allergic reaction?
Can allergies kill?
An Application
Video: Discovery-Body
Story- Allergies