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