Transcript Transport Systems

Transport Systems
• Why are they needed?
– To allow cells of organism to obtain oxygen,
nutrients and other substances
– To allow organism to eliminate wastes
Adaptations for Transport
• Simple Organisms:
– cells are in close contact with outside
environment, so transport can simply be
across the cell membrane
• Ex: Diffusion, osmosis, active transport
• Protists
– Amoeba & Paramecium
– Single celled
– Cell membrane in direct
contact with environment
– Transport directly through
diffusion and active transport
across cell membrane
– Cyclosis and cytoplasmic
streaming moves materials
inside cell
Hydra
– Two cell layers both in direct
contact with environment
• Ectoderm & Endoderm
– Outer layer (ectoderm) absorbs
nutrients from inner layer
(endoderm) lining gastro-vascular
cavity
– Wastes eliminated across cell
membrane to outside environment
ectoderm
endoderm
Adaptations for Transport
• Larger Organisms:
– Not all cells are close to location where
nutrients and needed substances (like oxygen)
are absorbed
– Need circulatory systems to transport materials
to and from all parts of the organism
– Forms a link between cells and the outside
environment
Analogy: People who live in a large city
How do they get food? Eliminate wastes?
Keys Parts to All
Circulatory Systems
– Fluid in which materials are transported
– Network of tubes or body spaces through
which fluid can flow
– Means of driving fluid through these spaces
(pump)
• Earthworm
– Most cells not in direct
contact with environment
– Closed circulatory
system
• Blood contained in vessels
or tubes
• Has dorsal and ventral blood
vessels
– Blood is red as it contains
hemoglobin to transport
oxygen to body tissues
– Five pairs of aortic
arches connect blood
vessels and pump blood
– Tubes branch into smaller
vessels and finally
microscopic capillaries
– Exchange of materials
takes place through walls
of capillaries
• There are so many
capillaries that every cell in
body is near one
• Grasshopper
– Open circulatory system
• Blood not always enclosed in vessels
• Blood flows directly into body spaces and “bathes” tissues
– Along its back it has a tubular heart to pump fluids
throughout body cavity
• Blood enters “heart” through holes in tube called ostia
– Colorless blood
• no hemoglobin
• doesn’t transport oxygen and carbon dioxide
• Gases are transported to body tissues through separate
tubes
Human Circulatory
System
• Closed Circulatory System (like all
vertebrates)
• Single 4 chambered heart (pump)
• Network of blood vessels including
arteries, veins and capillaries
• Blood flows through vessels,
carrying nutrients, wastes, oxygen
etc.
Types of Blood Vessels
• As blood flows through the circulatory
system it moves through three types of
blood vessels
– Arteries
– Veins
– Capillaries
Arteries
– Carry blood away from
the heart to the organs
and tissues of the body
– Walls are thick & elastic
Why?
– Blood pumped out of
heart is under great
pressure so walls have to
stretch and give with
each pump
– Divides into smaller arterioles and eventually
capillaries
They can get clogged!
Veins
– Return blood to the heart from the body tissues
– Smallest veins are called venules
– Walls are thin and only slightly elastic
The Importance of Valves:
– Veins have valves that
allow blood to flow in one
direction back to the heart
Why?
– Blood returning to heart is
not under as much
pressure and is sometimes
traveling against gravity
– Needs a way to prevent
backflow
• Contraction of skeletal muscles also aid in
pushing blood back to heart through veins
• Varicose veins: veins becomes stretched
and lose elasticity
Capillaries (microscopic)
– Connect arterioles and venules
in an extensive web
– Each cell in the body lies near
a capillary
– Capillary walls are a single cell thick
• Red blood cells pass through capillary in single file
• Diffusion happens across cell membrane
Thin walls allow for
exchange of
dissolved nutrients,
wastes, oxygen and
other substances with
individual cells
Gas, Nutrient and Waste
Exchange Happens at the Capillary
http://www.youtube.com/watch?v=Q530H1WxtOw&safe=active
Comparing Blood Vessels
The Heart
http://www.youtube.com/watch?v=
NF68qhyfcoM&safe=active
Heart
– Muscular organ as large
as your fist
– Acts as a pump
– Contractions force blood
through vessels
– Found slightly to the left of
middle of chest cavity
– Pericardium: tough
membrane that covers and
protects the heart
Structure of the Heart
4 chambered double pump
Atria: two upper chambers
– Pumps blood into lower ventricles
– Have thin walls
Ventricles: two lower chambers
– Pumps blood out to lungs and the
rest of body
– Have thick walls
– Left ventricle wall is thicker than right because it
pumps blood to entire body
– Right ventricle only pumps blood to lungs for
pulmonary circulation
Blood out to
entire body
Blood out to
lungs
Thinner
cardiac
muscle
Thicker
cardiac
muscle
Role of Heart Valves
Valves:
– Can open and close controlling
direction of blood flow in heart
• Atrioventricular Valves:
– allow blood to flow from upper
atria to lower ventricles
– Called the tricuspid and mitral
vallves
• Semilunar Valves:
– allow blood to flow from
ventricles into arteries that flow
away from heart
– Called the pulmonary valve and
aortic valve
The Flow of Blood
• Blood enters the 2 atria and
flows into the 2 ventricles
when heart muscle relaxes
• When heart contracts the
valves leading from the atria
close
• Blood is pushed from the
ventricles to rest of body
Pathway of Blood Flow
Blood goes to lungs
Right Side of Heart (“Blue Side”)
Right Atrium:
– Deoxygenated blood from body
enters through large vein called the
vena cava (inferior and superior)
– Contracts and squeezes blood
through valve into right ventricle
Right Ventricle:
– Pumps deoxygenated blood to the
lungs through pulmonary arteries
– Blood then takes on oxygen and
releases carbon dioxide to the lungs
Pathway of Blood Flow
Blood goes out to body
Left Side of Heart (“Red Side”)
Left Atrium:
– Oxygenated blood enters from the
from the lungs through the
pulmonary veins
– Contracts and squeezes blood
through valve into left ventricle
Left Ventricle:
– Pumps oxygenated blood out to
the rest of the body
– Blood pumped into the aorta
(largest artery in body)
Summary:
• Right Side of Heart:
– Gets oxygen depleted blood that has been to body
tissues
– Sends it to the lungs to get oxygen
• Left Side of Heart:
– Gets oxygen rich blood from lungs
– Pumps it out to the rest of the body
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=ap12504
Both sides pump
together
• Septum: tissue between right and left sides
of heart prevents mixing of oxygen rich and
poor blood
– “Blue Babies”:
• A fetus has an opening in its septum
• Body tissues don’t get enough oxygen
• Baby will often die or be very weak if not repaired
• Bill Nye:
• Circulatory Systems Part 1: The Heart
• http://www.youtube.com/watch?v=GbttJ5do9M&safe=active
Cardiac Muscle:
– Fibers form a network and never
stop beating
– Even when removed from the body
the heart will keep beating for awhile
if placed in a special solution
Heart of an Embryo
Pacemaker: (top of right atria)
• Regulates pumping of heart muscle
• Generates an electrical impulse that signals atria to
contract and then ventricles
• The medulla oblongata in brain stem regulates the
speed of the pacemaker
Pulmonary Circulation:
– From heart to the lungs and back
– Adds oxygen to blood
– Removes carbon dioxide from blood
– Blood circulates to lung capillaries which
surround tiny air sacs called alveoli where
gas exchange takes place
Blood changes color from
blue to red as oxygen
bonds to the hemoglobin
in red blood cells
Systemic Circulation:
– From left side of heart
oxygen rich blood is
pumped out to aorta and
rest of body
– Flows through arteries to
capillaries where
exchange of nutrients
and gases happens with
cells of body tissues
Coronary Circulation:
• Supplies blood to heart
muscle through coronary
blood vessels
• Branches right off the
aorta
• Heart muscle cells need
a constant supply of
nutrients and oxygen as
they never stop
contracting and beating
• A blood clot or fat
deposit in coronary
artery can lead to
heart attack
• Coronary bypass:
– uses a vein from leg to
create a detour around
blocked region
• Stint:
– placed inside artery to
keep it open and blood
flowing through
• Bill Nye: Part 2
• http://www.youtube.com/watch?v=RiYOuI7
iyp8&safe=active
The Beating of Your
Heart
• 2 main periods of relaxation and
contraction of heart muscle
– Diastole:
• relaxation of heart muscle (pressure drops)
• “filling”
– Systole:
• contraction of heart muscle (pressure rises)
• “pumping”
Heart Sounds
• Heart valves open and close making “lub-dub”
sound
– Lub = closing AV valves (between atria and ventricles)
– Dub = closing semilunar valves ( to aorta & pulmonary
arteries)
• If there is a leak or backflow through valves you get
a heart murmur
• Pulse:
– How many beats per minute
– Measured at your artery
Resting Heart Rate
• At neck or wrist
• Count how many beats in 30 seconds at
rest
• Double that amount for how many beats
per minute
Rate after Exercise
• At neck or wrist
• Count how many beats in 30 seconds at
rest
• Double that amount for how many beats
per minute
• Why is there a difference?
Blood Pressure:
– force that blood exerts on
the walls of your arteries
– Measured with a
sphygmomanometer
– Measures high pressure,
low pressure (ex: 120/80)
Where is Blood Pressure Highest?
Cardiovascular Diseases
• Stroke:
– A blood clot in
brain prevents
flow of blood to
brain tissue
Cardiovascular Diseases
• Heart Attack:
– blood supply to heart
is cut off
– caused by a blood clot
or blockage in
coronary artery
causing coronary
thrombosis
Hypertension:
– High blood pressure
– Often be caused by atherosclerosis or
“hardening” of the arteries
– Arteries become not as elastic and narrower
as cholesterol and other fatty materials collect
on the inner walls
Preventing Heart
Disease
• Don’t smoke
• Get blood pressure checked
• Don’t eat food high in cholesterol
– butter, mayo, fatty meats
• Cut down on salt
• Exercise regularly to strengthen your heart and
improve circulation
• Avoid obesity
• Learn to manage stress and anxiety
• Bill Nye: Part 3
• http://www.youtube.com/watch?v=YlCX2N
CEgcM&safe=active
• How does the heart work:
• http://www.youtube.com/watch?v=H04d3rJ
CLCE&safe=active
• The Circulatory System Summary
– http://www.youtube.com/watch?v=hLNR5Pu2
ehQ&safe=active