Download Blood - Mrs. Brenner`s Biology

Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 32
Circulation and
Cardiovascular Systems
Lecture Outline
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Outline
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•
•
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32.1 Transport in Invertebrates
32.2 Transport in Vertebrates
32.3 The Human Cardiovascular System
32.4 Blood
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32.1 Transport in Invertebrates
• Circulatory System
• Functions to move fluid between various parts of the body
• Small aquatic animals with no circulatory system
– Each cell is exposed to water and can independently exchange
gases and eliminate wastes
• Pseudocoelomates
– Use a fluid-filled body cavity as a means of transporting
substances
• Coelomate echinoderms
– May still rely on body fluids for the purpose of locomotion
3
Aquatic Animals Without a Circulatory
System
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food
undigested
waste products
mouth
enzymes
food
gastrovascular
cavity
arm
nutrient
uptake by
endocytosis
aboral side
a. Hydra
eyespot
pharynx
bivalve mollusc
c. Red sea star, Mediastar
7Χ
b. Flatworm
gastrovascular
cavity
(a): © CABISCO/Visuals Unlimited; (b): © Lester V.Bergman/Corbis; (c): © Randy Morse, GoldenStateImages.com
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Transport in Invertebrates
• Invertebrates with a Circulatory System
• Two types of circulatory fluids:
– Blood - contained within blood vessels
– Hemolymph – mixture of blood and tissue fluid that fills the body
cavity and surrounds internal organs
• Open Circulatory System
– Heart pumps hemolymph via vessels
– Vessels empty into tissue spaces
• Closed Circulatory System
– Heart pumps blood to capillaries
– Gases and materials diffuse to and from nearby cells
– Vessels return blood to heart without contact between blood and
tissues
5
Open vs. Closed Circulatory Systems
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dorsal
tubular
aorta ostia heart
heart
ventral
blood
vessel
dorsal
blood
vessel
lateral
vessel
ostia
valve
heart
heart
hemolymph
hemocoel
a. Open circulatory system
capillaries
b. Closed circulatory system
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32.2 Transport in Vertebrates
• All vertebrates have a closed circulatory system called a
cardiovascular system
• Vertebrate heart:
– Atria of heart receive blood from general circulation
– Ventricles of heart pump blood out through blood vessels
• Vertebrate vessels:
–
–
–
–
–
Arteries - Carry blood away from heart
Arterioles – Lead to capillaries
Capillaries - Exchange materials with tissue fluid
Venules - Lead to veins
Veins - Return blood to heart
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Transport in Vertebrates
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Outer layer
fibrous connective tissue
Middle layer
smooth
muscle
elastic
tissue
Inner layer
endothelium
Outer layer
Middle layer
Inner layer
fibrous connective tissue
smooth elastic
muscle tissue
endothelium
a. Artery
endothelium
closed valve
c. Vein
b. Capillary
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Anatomy of a Capillary Bed
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artery
arteriole
O2-rich
blood flow
precapillary
sphincter
arteriovenous
shunt
venule
O2-poor
blood flow
vein
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Transport in Vertebrates
• Comparison of Circulatory Pathways
• Fish - Blood flows in single loop
– Single atrium and single ventricle
• Amphibians - Blood flows in double loop
– Systemic circuit and pulmonary circuit
– Two atria with a single ventricle
• Other vertebrates - Blood flows in a double loop
– Heart divided by septum into separate sides
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Comparison of Circulatory Circuits
in Vertebrates
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pulmonary
capillaries
pulmonary
capillaries
gill capillaries
pulmonary
circuit
pulmonary
circuit
right
atrium
ventricle
ventricle
heart
left
atrium
right
atrium
right
ventricle
heart
atrium
left
atrium
left
ventricle
aorta
aorta
aorta
systemic
circuit
systemic
capillaries
systemic
circuit
systemic
capillaries
systemic
capillaries
a.
b.
c.
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32.3 The Human Cardiovascular
System
• The Human Heart
– Fist-sized
– Cone-shaped
– Muscular organ (cardiac fibers)
– Lies within a membranous sac (the
pericardium)
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The Human Cardiovascular
System
• Structure of the Heart
– Septum separates the heart into left & right sides
– Each side has two chambers
• Upper two chambers are the atria
– Thin-walled
– Receive blood from circulation
• Lower two chambers are the ventricles
– Thick-walled
– Pump blood away from heart
13
External Heart Anatomy
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lung
left subclavian artery
left common carotid artery
brachiocephalic artery
sternum
superior vena cava
aortic arch
aorta
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins
b.
pericardium heart
left atrium
left cardiac vein
right atrium
right coronary artery
left ventricle
right ventricle
Inferior vena cava
apex
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a.
b: © SIU/Visuals Unlimited
The Human Cardiovascular
System
• Valves open and close to control blood flow
through heart
– Atrioventricular valves
• Tricuspid valve between right atrium and ventricle
• Bicuspid valve between left atrium and ventricle
– Semilunar valves
• Pulmonary semilunar valve between right ventricle and
pulmonary trunk
• Aortic semilunar valve between left ventricle and aorta
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Internal View of the Heart
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left subclavian artery
left common carotid artery
brachiocephalic artery
cardiac
muscle cell
mitochondrion
superior vena cava
aorta
intercalated
disk
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins
semilunar valve
left atrium
right atrium
gap junction
atrioventricular
(bicuspid) valve
atrioventricular
(tricuspid) valve
chordae tendineae
b.
papillary muscles
right ventricle
septum
left ventricle
inferior vena cava
a.
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b: © Dr. Don W. Fawcett/Visuals Unlimited;
The Human Cardiovascular
System
• Path of Blood Through Heart
– Blood returning to heart from systemic circuit
• Venae cavae return blood to the right atrium
• Right atrium pumps blood through the tricuspid valve to right
ventricle
• Right ventricle pumps blood through the pulmonary semilunar valve
to the pulmonary circuit
– Blood returning to heart from pulmonary circuit
• Enters left atrium
• Left atrium pumps blood through the bicuspid valve to the left
ventricle
• Left ventricle pumps blood through the aortic semilunar valve to the
systemic circuit
– Oxygen-poor blood never mixes with oxygen-rich
blood (in humans)
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The Human Cardiovascular
System
• Heartbeat
• Systole - Contraction of heart chambers
• Diastole - Relaxation of heart chambers
• Cardiac cycle - Two-part pumping action that takes
about a second
– Blood collects in atria, the atria contract
• Pushes blood through tricuspid and mitral valves into the
resting lower ventricles
• This phase (the longer of the two) is called diastole
– Second part begins after the ventricles fill
• Ventricles contract
• This is called systole
– After blood moves into the pulmonary artery and aorta, the
ventricles relax
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Stages in the Cardiac Cycle
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semilunar
valves close
(“dub”)
aortic semilunar valve
bicuspid valve
pulmonary
trunk
semilunar
valves
aorta
left
atrium
right
atrium
left
ventricle
superior
vena cava
right
atrium
inferior
vena cava
c.
a.
right
ventricle
pulmonary
trunk
d.
aorta
atrioventricular (AV)
valves close
(“lub”)
b.
represents
contraction
(d): © Biophoto Associates/Photo Researchers, Inc.
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The Human Cardiovascular
System
• Heartbeat (continued)
– The pulse is a wave effect passing down the
walls of the arterial blood vessels when the
aorta expands and recoils falling ventricular
systole
– Rhythmic contraction of the heart is due to the
cardiac conduction system
• Sinoatrial node (SA) keeps the heartbeat regular
• Atrioventricular node (AV) signals ventricles to
contract
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The Human Cardiovascular
System
• Electrocardiogram (ECG)
– A recording of electrical changes that occur in the
myocardium during cardiac cycle
– When SA node triggers an impulse, the atrial fibers
produce an electrical charge (P wave)
– The P wave indicates that the atria are about to
contract
– The QRS complex signals that the ventricles are about
to contract and the atria are relaxing
– T wave is due to electrical changes occurring as the
ventricular muscle fibers recover
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Conduction System of the Heart
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R
SA node
T
P
AV node
Q
branches of
atrioventricular
bundle
S
b. Normal ECG
Purkinje fibers
a.
c. Ventricular fibrillation
d. Recording of an ECG
d: © David Joel/MacNeal Hospital/Getty Images
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The Human Cardiovascular
System
• The human cardiovascular system
includes two major circular pathways:
– Pulmonary Circuit
• Takes oxygen-poor blood to the lungs and returns
oxygen-rich blood to the heart
– Systemic Circuit
• Takes oxygen-rich blood from the heart to tissues
throughout the body and returns oxygen-poor
blood to the heart through the venae cavae
23
Path of
Blood
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CO2
head and arms O2
carotid artery
(also subclavian
artery to arms)
jugular vein
(also subclavian
vein from arms)
O2
CO2
O2
CO2
lungs
pulmonary
artery
pulmonary
vein
superior
vena cava
aorta
heart
inferior
vena cava
hepatic
vein
mesenteric
arteries
liver
hepatic
portal
vein
renal
vein
digestive
tract
renal
artery
kidneys
Iliac vein
iliac
artery
CO2
O2
trunk and legs
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The Human Cardiovascular
System
• Blood Pressure
– Contraction of the heart supplies pressure that keeps
blood moving in the arteries
• Systolic pressure results from blood forced into the arteries
during ventricular systole
• Diastolic pressure is the pressure in the arteries during
ventricular diastole
• Normally measured with a sphygmomanometer on the
brachial artery
• Expressed in the form: Systolic “over” Diastolic
– Ex: 120/80
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The Human Cardiovascular
System
• Blood Pressure (continued)
– In arteries, the pressure of the blood forces it to move
forward
– Blood pressure falls as blood flows from the aorta into
arteries and arterioles
– Blood flow in the capillaries is slow
– Blood pressure in the veins is too low to move blood
back to the heart
• Skeletal muscle contraction pushes blood in the veins toward
the heart
• Veins have valves to prevent backward flow of blood
• A respiratory pump reduces pressure in the thoracic cavity to
cause blood to move from the abdominal cavity into the
thoracic cavity
26
Velocity and Blood Pressure Related to Vascular
Cross-Section
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arteries
arterioles capillaries
Magnitude
blood
pressure
venules
veins
total
cross-sectional
area of
vessels
velocity
Blood Flow
27
Cross Section of a Valve in a Vein
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to heart
a. Contracted skeletal muscle
pushes blood past open valve.
to heart
b. Closed valve prevents
backward flow of blood.
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The Human Cardiovascular
System
• Cardiovascular Disease (CVD)
• Hypertension - High blood pressure
• Atherosclerosis - Accumulation of fatty materials
between the inner linings of arteries
• Stroke - Cranial arteriole bursts or is blocked by an
embolus
• Heart attack (myocardial infarction) – Coronary artery
becomes completely blocked
• Angina pectoris – Painful squeezing sensation from
myocardial oxygen insufficiency due to partial
blockage of a coronary artery
29
Coronary Arteries and Plaque
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coronary artery
ulceration
lumen of vessel
fat
cholesterol
crystals
atherosclerotic
plaque
© Biophoto Associates/Photo Researchers, Inc.
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32.4 Blood
• Blood
– Transports substances to and from capillaries
for exchange with tissue fluid
– Helps destroy pathogenic microorganisms
– Distributes antibodies
– Maintains water balance and pH
– Regulates body temperature
– Carries platelets and factors to promote
clotting and prevent blood loss
31
Composition of Blood
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Plasma
Formed Elements
55%
Type
Function
Type
Water
(90–92% of
plasma)
Maintains blood volume;
transports molecules
Red blood cells
(erythrocytes)
Plasma proteins
(7–8% of plasma)
Maintain blood osmotic pressure and pH
Transport O2 and help
transport CO2
Globulins
Fibrinogen
Number (per mm 3 blood)
4 million–6 million
45%
Transport; fight infection
Blood clotting
Salts
(less than 1% of
plasma)
Maintain blood osmotic pressure and pH;
aid metabolism
Gases
(O2and CO2)
Cellular respiration
Nutrients
(lipids, glucose,
and amino acids)
Food for cells
Wastes
(urea and
uric acid)
End product of metabolism;
excretion by kidneys
Hormones
Aid metabolism
White blood cells
(leukocytes)
5,000–1 1,000
Fight infection
Neutrophils
Monocytes
4–8%
Lymphocytes
40–70%
20–45%
Eosinophils
Basophils
1–4%
0–1%
Platelets
(thrombocytes)
Aid clotting
150,000–300,000
32
Blood
• Red Blood Cells (RBCs)
– Small, biconcave disks
– Lack a nucleus and contain hemoglobin
• Hemoglobin contains
– Four globin protein chains
– Each associated with an iron-containing heme
– Manufactured continuously in bone marrow of skull,
ribs, vertebrae, and ends of long bones
33
Blood
• Blood Types
– Determined by the presence or absence of a
surface antigen
• ABO System
• Rh System
– Antibodies in the plasma can cause
agglutination
• Cross-reactions occur when antigens meet
antibodies
34
Blood Type
35
Matched Blood Transfusion
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500x
antigen
type A blood
of donor
+
no binding
anti-B antibody of
type A recipient
red blood cell
no agglutination
© J. C. Revy/Phototake
36
Mismatched Blood Transfusion
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500x
antigen
type A blood
of donor
+
binding
anti-A antibody of
type B recipient
agglutination
© J. C. Revy/Phototake
37
Blood
• During pregnancy, if the mother is Rh
negative and the father is Rh positive, the
child may be Rh positive.
– Rh-positive red blood cells may leak across
the placenta
– The mother will produce anti-Rh antibodies.
– Antibodies may attack the embryo in a
subsequent pregnancy
38
Blood
• White Blood Cells (WBCs)
– Most types are larger than red blood cells
– Contain a nucleus and lack hemoglobin
– Important in inflammatory response
– Divided into two categories:
• Granular leukocytes
• Agranular leukocytes
39
Blood
• White Blood Cells (WBCs)
– Granular Leukocytes
• Contain granules composed of proteins and enzymes
used to help defend the body against invading
organisms
• Neutrophils – phagocytize and digest bacteria
• Basophil – contain histamine
• Eosinophils – involved in fighting parasitic worms,
among other activities
40
Blood
• White Blood Cells (WBCs)
– Agranular Leukocytes
• Lack granules
• Monocytes – migrate into tissues in response to
chronic, ongoing infections
– Differentiate into macrophages
» Fight infection, release growth factors that increase the
production of WBCs by the bone marrow
• Lymphocytes
– T cells and B cells involved in the immune response and
antibody production
41
Blood
• Platelets
– Result from fragmentation of megakaryocytes
– Involved in blood clotting (coagulation)
• A blood clot consists of:
– Platelets
– Red blood cells
– Fibrin threads
42
Blood Clotting
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red
fibrin
blood cell threads
platelet plug
1. Blood vessel is punctured.
2. Platelets congregate and
form a plug.
fibrin threads
3. Fibrin threads form and
trap red blood cells.
© Eye of Science/Photo Researchers, Inc.
43
Blood
• Capillary Exchange
• Capillaries are very narrow and tiny RBCs
must go through single file
• Walls of capillaries are very thin to facilitate
diffusion of nutrients, gases, and wastes
– Water exits a capillary near the arterial end
– Water enters a capillary near the venous end
– Solutes diffuse into and out of a capillary according
to their concentration gradient
• Oxygen and nutrients diffuse out of capillaries
• Carbon dioxide and wastes diffuse into the capillary
44
Capillary Exchange
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from heart
to heart
Arterial end
Tissue fluid
Blood pressure is higher
than osmotic pressure.
Net pressure out.
carbon
oxygen amino
acids
glucose dioxide
Venous end
Osmotic pressure is higher
than blood pressure.
Net pressure in.
water
wastes
water
salt
arteriole
smooth
muscle fiber
plasma
protein
osmotic pressure
blood pressure
venule
45
Capillary Bed
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precapillary sphincters
arteriole
tissue fluid
lymphatic capillary
blood capillary
excess tissue fluid
lymphatic duct
venule
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