Biology 20Unit 4: Energy and Matter
Exchange in HumansTopic One
Mammals and Humans
Fish
Reptiles
Two Chamber
Heart
Three Chamber
HeartFour
Chamber Heart
Five Circulatory Functions1. Carries nutrients to cells,
wastes away from cells2. Carries chemical messengers
(hormones) from cells in one part of the body to distant target tissues
3. Distributes heat throughout the body
4. Along with the kidneys, maintains acceptable levels of body fluids
5. Defense against invading organisms( White blood cells)
FUNCTION OF BLOOD VESSELS
Artery
ArteriolesVenules
Vein
Capillaries
http://www.youtube.com/watch?v=CjNKbL_-cwA&feature=related&safety_mode=true&persist_safety_mode=1
Types of vessels video: (1 min)
Arteries (Thickest)
Veins (In between)
Capillaries (Thinnest)
Topic 1-2 Blood Vessels
Topic 1-2 Blood Vessels•There are three kinds of blood vessels in the circulatory system:
•ARTERIES (THICKEST)•CAPILLARIES (THINNEST)•VEINS (IN BETWEEN)
Arteries and Arterioles• Function
– carry blood AWAY from the heart– Arterioles contain smooth muscle to regulate
amount of blood flowing to tissues– Arterioles vasodilate (get wider) and
vasoconstrict (get narrower)• Structure
– Thick, muscular walls composed of three distinct layers
– Outer and inner layers = rigid connective tissue.– Middle layer = muscle fibers
Connective Tissue
Smooth Muscle
Connective Tissue
Arteries and Arterioles• A pulse is created when
blood passes through an artery
• A person’s blood pressure is the pressure of the blood in an artery when the heart contracts
Will cutting an artery kill you?
Capillary Function
Function:•Diffusion and osmosis•Moves nutrients and oxygen into the tissues•Moves wastes and carbon dioxide into the blood
Capillary wall is one cell layer
thick
Tissue
O2 and nutrients
CO2 and wastes
Capillary Function• Smallest blood vessel
– Red blood cells (RBC) pass through only one at a time• INTERESTING FACT
– Damaging a capillary bed causes BRUISING – as blood rushes into the interstitial spaces
Capillary Structure• Precapillary sphincter
muscles regulate the movement of blood from the arterioles into capillaries
• No cell is further than two cells away from a capillary
Rings of smooth muscles regulating blood flow into the capillaries
Veins and Venules• Capillaries merge and
become progressively larger vessels called venules– Venules = small veins
• The venules come together and eventually form veins
Valve
Smooth muscle
Veins Structure & Function• Structure:
– Thin walled, less smooth muscle than arteries
– Larger in diameter than arteries– Contain one way valves
• Function: – Carry blood back to the heart
Flow of Blood through Vessels
Artery Arteriole Capillaries Venule Veins
Oxygenated (high O2) Deoxygenated (low O2)
Flow of Blood through Vessels
Capillaries
VenuleVein
Artery
Arteriole Diffusio
n
Veins & Gravity
The return of blood to the heart involves 2 problems:
1. Blood is under low pressure not sufficient to drive the blood back to the heart
2. Blood especially from the lower limbs must move up against gravity Varicose Veins
Mechanisms to Help Veins Return Blood to The Heart: A solution!!
• 1) One way valves: only allow blood to move towards the heart
• 2) Skeletal muscle contractions push blood in the vein back to the heart
Blood cannot travel backwards
One way valves
Vasodilation and Vasoconstriction
Normal Arteriole
Vasodilation Vasoconstriction
The walls of arterioles are muscular and elastic, so they expand and contract. This is called vasodilation and vasoconstriction.
•Reduces blood flow to the tissues• conserve heat•decreases the diameter of the blood vessel.
Vasodilation•Increases blood flow and delivery of nutrients to the tissues•Release of heat
Normal Arteriole
Vasoconstriction
Topic 1-3 Heart Structure and Function
Whale heart
General Structure• Size of a fist• Made of cardiac muscle tissue
– Only found in the heart • Two pumps (left and right):
– Two sides of the heart are separated by wall of muscle called the septum
– Both sides pump at the same time
Right Side Left Side
Blood to the lungs
Blood from the body Blood from the lungs
Blood goes to the body
Aorta
Semilunar valve
Bicuspid (AV-valve)
Left atrium
Left pulmonary veins
Left pulmonary artery
Descending Aorta
Left Ventricle
AV=Atrioventricular
Right Ventricle
Inferior Vena Cava
Septum
Tricuspid Valve (AV-valve)
Semilunar valve
Right Pulmonary Veins
Right pulmonary artery
Superior Vena Cava
Right Atrium
Tracing Blood Flow Review
Right Left
Superior/inferior vena cava
Right atrium
Tricuspid valve/AV valve
Right ventricle
Semilunar valve
Right/left pulmonary artery
LUNGS
Pulmonary veins
Left atrium
Bicuspid/AV valve
Left ventricle
Semilunar valves
aorta
BODY
The Pathway of Blood Through the Heart
http://www.youtube.com/watch?v=H04d3rJCLCE&feature=related&safety_mode=true&persist_safety_mode=1
Heart video
Coronary VesselsCoronary Vessels = blood vessels that deliver oxygen-rich blood to the heart muscle
– Blockage of these vessels can cause angina (chest pain) or heart attack
Left sidedeals with (RED)
oxygenated blood
Left ventricle very muscularPumps blood to entire body
Right side deals with (BLUE)
deoxygenated blood
aorta
Chambers: Atria• Structure: Thin wall• Function: Receives blood from
the veins– Right atrium receive blood
from the superior and inferior vena cava (body)
• pumps blood to right ventricle
– Left atrium receive blood from the pulmonary veins (lungs)
• Pumps blood to the left ventricle
Chambers: Ventricles• Structure:
– Muscular thick walled heart chambers
• Functions:– Pumps blood to the arteries– Right ventricle pumps blood
into the pulmonary artery (to the lungs)
– Left ventricle pumps blood into the aorta (body)
Left Ventricle
• Why is the left ventricle more muscular than the right ventricle?
• It must work harder to pump blood to the entire body and not just to the lungs
Chambers: Ventricles
Left
Ventri
cle
Right Ventricle
Valves: Atrioventricular (AV)• Structure: – Flaps of tissue– Located between the atria
and ventricles• Function: – Prevent the backflow of
blood from the ventricles into the atria
– Supported by band of tissue known as the chordae tendinae
Right AV valve = tricuspid valve
Left AV valve = bicuspid valve
Valves: Semilunar• Structure: Half moon
shaped valves at base of arteries leaving the heart
• Function: Prevents
backflow of blood into the ventricles
Atrioventricular
Semilunar
Vessels: Vena Cava• Superior Vena Cava:
– Carries blood that is low in O2 and high in CO2 (deoxygenated) from the head to the right atrium
• Inferior Vena Cava:– Carries blood that is low in O2 and high in CO2 (deoxygenated)
from the lower tissues (ex – legs) of the body to the right atrium
Vessels• Pulmonary artery
– Carries deoxygenated blood from the heart to the lungs
• Pulmonary veins– Four veins that carry oxygenated blood
from the lungs back to the heart• Aorta
– Carries oxygenated blood from the heart to the body
http://www.youtube.com/watch?v=NJzJKvkWWDc&safety_mode=true
Bozeman Circulatory System 11:35
Blood Pathway in HeartCardiac Cycle
• A cardiac cycle is one heartbeat• The heart beats 60-75 times per minute• Two sides of the heart beat in unison-first the atria
then the ventricles
• Systole = heart (ventricles) contracts• Diastole = heart (ventricles) relaxes
Cardiac Cycle: Stages1. Heart relaxed
• The atria fill with blood
2. Atria contract• A-V valves open, ventricles fill
and the semilunar valve closes (creating a dubb sound)
3. Ventricles contract• A-V valves close, blood is forced
out of the arteries and the semilunar valve open (creating a lubb sound)
Heart Sounds – Link • Heart sound: “lubb-dubb”
– “Lubb”: AV-valves closing (systole phase, heart (ventricles)contracts)
– “Dubb’: semilunar valves closing (diastole phase, heart (ventricles) relaxes)
http://www.youtube.com/watch?v=RiYOuI7iyp8&safety_mode=true&safe=active
Bill Nye- heart 3:50 – 4:30
Electrocardiograms• Electrical impulses from the heart
are displayed on a graph called an electrocardiograph
• Used to diagnose heart problems• Compare tracings to determine
areas of heart damage
Bill Nye- ultrasound of heart 3:50 -end
http://www.youtube.com/watch?v=YlCX2NCEgcM&safety_mode=true&safe=active
Atria filling
Atria and ventricles fill
A-V open
Atria contract “dubb”Diastole
A-V valves close “lubb”
Semilunar valves open. Ventricles contractSystole
Aorta
Ventricles filling
Pulmonary artery
There are 2 main circulatory pathways for blood in the body:
1. Pulmonary Circulation (lungs)2. Systemic circulation (body)
Topic 1-4 Blood PathwaysPulmonary Circulation:
To Lungs
Systemic Circulation: To bodyhttp://www.youtube.com/watch?
v=0jznS5psypI&feature=related&safety_mode=true&persist_safety_mode=1
Pulmonary and System circulation video
Pulmonary Circulation
– Carries deoxygenated (oxygen poor) blood to the lungs (via pulmonary arteries)
– At the lungs blood releases carbon dioxide and picks up oxygen
– Oxygenated (oxygen rich) blood is carried back to the heart (via pulmonary veins)
Systemic CirculationVessels that carry blood to and from the body cells
Ex: coronary, renal, portal
(highlight letters CPR)
Coronary Circulation• Supplies blood to the heart muscle
– There is a right and left coronary artery
Left Coronary Artery
Right Coronary Artery
Systemic Circulation cont...• Portal
– Supplies blood to the digestive organs and liver
• Renal– Supplies blood to the
kidneys
Topic 1-5 Blood Pressure
Blood Pressure• Expressed as 2 numbers
(Numbers are ± 10)
• Measured with a sphygmomanometer– “Blood pressure cuff”– The cuff closes off flow on
brachial artery– The cuff is deflated until a
sound is heard
Normal blood pressure:
120 mmHg
70 mmHg
Systolic pressure
Diastolic pressure
• First sound is systolic pressure– ventricles contracting– normally 120 mm Hg– listen for sound with stethoscope
• When you stop hearing the sound, it represents diastolic pressure– ventricles relaxed and filling– normally 70 - 80 mmHg
Measuring Blood Pressure
Systolic Pressure• Heart contracted/relaxed:
Pressure caused by ventricles contracting
• AV Valves: AV valves closed• Semilunar Valves: semilunar
valves open• Blood heading out of heart to
body & lungs
Diastolic PressureOpposite of Systolic • Heart contracted/relaxed:
Heart(ventricle) is relaxed and fills with blood
• AV Valves: AV valves open• Semilunar Valves: Semilunar
valves closed • Pressure is highest in arteries
closest to heart
Pressure gets lower further away from heart
Blood Pressure is HIGHEST in the ARTERIES and LOWEST in VEINS
Bloodslows in
capillaries
Blood Velocity in Vessels
BLOOD VELOCITY IN VESSELS
Why does blood flow slowly through the capillaries?
Blood flows slowly through the capillaries so that
there is more time for diffusion.
The SPEED at which blood travel is fastest is in ARTERIES and slowest in CAPILLARIES.
Largest CS area
The greatest SURFACE AREA of blood vessels is in the CAPILLARIES
Surface Area in Vessels
For diffusion.
Factors affecting Blood Pressure• Heart Rate and
Contraction Force
• Diameter and Elasticity of Blood Vessel Walls
• Amount of Blood
What factors would Increase Blood Pressure?• Decrease in diameter or
vasoconstriction (arterioles) would increase blood pressure due to an increase in resistance to flow (stress)
• Increased amount of blood will also increase blood pressure (ex - when you drink water after a salty meal.)
• Alcohol• genetics
What factors would Decrease Blood Pressure?
• Exercise: increases blood vessel diameter, or vasodilation
• Loss of blood• Less salt in diet• Eating right
WHAT HAPPENS WHEN PEOPLE AGE?• Both systolic and diastolic blood pressures
increase as people age!
• Why? Arteries harden, less active, muscles cannot stress as well
http://www.mhhe.com/biosci/genbio/virtual_labs/BL_08/BL_08.html
Blood Pressure Activity
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