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Blood, Oxygen and Circulation
• Blood everywhere—
capillaries
• Oxygen for Cell
Respiration
• Circulatory System
– Blood Cells
– Arteries and veins
– Heart and Chambers
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Blood is everywhere…how?
• Circulatory system
– Big vessels leave from
pump—heart
– Divide and split to all
major parts of body:
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Limbs
Head
Guts
Major organs
Body wall
Skeleton, muscles
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
“Stuff” moves in and
out of blood
• From/to outside world
– O2, CO2 in lungs
– Nutrients in guts/digestive
system
– metabolic wastes—
kidneys/urinary system
• From/To cells of body
– Every single tissue
– O2, CO2, nutrients, waste
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
“Stuff” moves in and out by diffusion
Inside organs, muscles, structures, bones, big vessels divide into smaller and
smaller vessels and then into network-like capillary beds. This is where
diffusion can happen rapidly, at the microscopic level. Then, to get blood back
to heart, capillaries feed into smaller veins into larger and larger veins into
major veins that return to heart
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Capillaries infiltrate every
tissue of the body (so
blood is everywhere!)
• Why? Because the cells
that make up every tissue
need
– Oxygen (for cellular
respiration)
– Nutrients (for cell
metabolism)
– Immune cells nearby (to
eliminate invading microbes)
– Removal of waste (from cell
metabolism)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Capillaries—schematic view
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Very schematic view of what happens in a capillary
Arteries bring blood from heart. Veins take blood to heart.
Network of capillaries really connects artery to vein
Diffusion of needed substances only happens in microscope, thin-walled
capillaries
• See next slide for more realistic view of capillary network or “capillary bed.”
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Capillaries—more realistic views
More realistic drawing
showing network of capillaries
connecting arteries to veins
and threading through tissue.
Open-ended lymph capillaries
pick up excess fluid from
tissue and also give immune
cells route back into blood
circulation
Photomicrograph of
stained blood vessels of
retina showing intricate
capillary network
Electron micrograph
showing arterioles,
tiniest of arteries,
splitting into virtual sheet
of capillary network that
brings blood into very
close proximity with
almost every cell in the
tissue.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Heart pumps blood
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If more oxygen is needed, heart pumps faster
Brain, guts are big users of oxygen
But muscles under physical activity are biggest user.
During exercise, more muscles are active, more oxygen is needed so heart
pumps faster
• Pulse is measure of how fast heart is pumping
• Learn to measure your own pulse—you’ll need to do this for the Lab Project
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Blood Pressure
• Blood pressure
measures force of
blood against wall of
vessels
• Systolic pressure is
highest point, as blood
is being forced out of
heart by contraction of
heart muscle
• Diastolic pressure is
lowest point, between
heart “beats,” when
heart is inactive
• Would you expect
these values to be
affected by physical
exercise—find out in
Lab Project for this unit!
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Why do cells need oxygen?
• Remember Cell Respiration (breaks down glucose to make
high-energy ATP bonds that can be used for cell metabolic
reactions)
– Glycolysis (can happen in absence of oxygen=fermentation)
– Citric acid cycle
– Electron transport chain
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
• Every step of
respiration
catalyzed by
proteins that are
coded for in the
DNA
• Can you find
cellular
respiration on the
E. coli metabolic
map?
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
How does oxygen get into blood?
• Oxygen diffuses into blood in lungs
• In lungs, bronchioles (air tubes) branch and branch, finally
ending in tiny sacs called alveoli.
• Each alveolus is surrounded by capillaries
• Oxygen diffuses across super-thin epithelial tissue of alveolus,
across super-thin epithelial tissue of capillary, across red blood
cell membrane and is held by Hemoglobin protein molecules in
Larry M. Frolich, Ph.D.
red blood cells
Biology Department, Yavapai College
Blood
Cells
• Red blood cells are one of several types of blood cells
• Each second, 3 million new red blood cells are formed by a special kind of
mitosis
• Red blood cells have no nucleus or organelles. They are just full of
Hemoglobin (Hb)
• Thus, Hb was one of the earliest proteins to be isolated and understood.
• It’s role in sickle cell anemia also helped to unlock the genetics and
molecular structure of Hemoglobin (see web links on the course website)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Blood
Cells
• White blood cells fight invading microbes as part of the immune
system
• Include
– Lymphocytes—recognize invaders
– Monocytes and neutrophils—actually consume or engulf microbes
– Basophils—release substances that trigger the other cells.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
What Does C-V System do?
• Circulate blood throughout entire body
for
– Transport of oxygen to cells
– Transport of CO2 away from cells
– Transport of nutrients (glucose) to cells
– Movement of immune system components
(cells, antibodies)
– Transport of endocrine gland secretions
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
How does it do it?
• Heart is pump
• Arteries and veins are main tubes (plumbing)
– Arteries Away from Heart
– Veins to Heart
• Diffusion happens in capillaries (oxygen,
CO2, glucose diffuse in or out of blood)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Overall Organization of System
• Heart/Great Vessels-1 Route
• Smaller aa. vv.--many
routes (collateral
circulation)
• Capillaries—network
where diffusion
occurs
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Artery/Vein differences
Arteries (aa.)
Direction Blood Away from
of flow
Heart
Pressure Higher
Veins (vv.)
Blood to Heart
Walls
Lumen
THICKER: Tunica
media thicker than
tunica externa
Smaller
THINNER: Tunica
externa thicker
than tunica media
Larger
Valves
No valves
Valves (see next)
Lower
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Capillaries
• Microscopic--one
cell layer thick
• Network
• Bathed in
extracellular matrix
of areolar tissue
• Entire goal of C-V
system is to get
blood into
capillaries where
diffusion takes
place
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Two circulatory paths
Systemic
Pulmonary
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
GREAT VESSELS
•Aorta
•IVC, SVC
•Pulmonary Trunk
•Pulmonary Veins
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Heart Chambers and Valves
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Heart Chambers and Valves
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Heart Chambers
• Right Atrium (forms most of posterior of heart)
– Receives O2-poor blood from body via IVC, SVC, Coronary sinus
– Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale
• Right Ventricle
– Receives O2-poor blood from right atrium through tricuspid valve
– Pumps blood to lungs via Pulmonary Semilunar Valve in
pulmonary trunk
• Left Atrium
– Receives O2-rich blood from 4 Pulmonary Veins
• Left Ventricle (forms apex of heart)
– Receives blood from Left Atrium via bicuspid valve
– Pumps blood into aorta via Aortic Semilunar Valve to bod
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Heart Valves: Lub*-Dub**
• *Tricuspid Valve: Right AV valve
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3 Cusps (flaps) made of endocardium and CT
Cusps anchored in Rt. Ventricle by Chordae Tendinae
Chordae Tendinae prevent inversion of cusps into atrium
Flow of blood pushes cusps open
When ventricle in diastole (relaxed), cusps hang limp in ventricle
Ventricular contraction increases pressure and forces cusps closed
• *Bicuspid (Mitral) Valve: Left AV valve
– 2 cusps anchored in Lft. Ventricle by chordae tendinae
– Functions same as Rt. AV valve
• **Semilunar valves: prevents backflow in large arteries
– Pulmonary Semilunar Valve: Rt Ventricle and Pulmonary Trunk
– Aortic Semilunar Valve: Left Ventricle and Aorta
– 3 cusps: blood rushes past they’re flattened, as it settles they’re pushed
down (valve closed)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Another View
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Location of Heart in Thorax
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Fetal Circulation
•No circulation to lungs
•Foramen ovale
•Ductus arteriosum
•Circulation must go to placenta
•Umbilical aa., vv.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College