Unit 2 NotesUnit 2 Notes

The Circulatory SystemThe Circulatory System

Overview of the Circulatory Overview of the Circulatory SystemSystem

Cells need oxygen and Cells need oxygen and nutrients in order to nutrients in order to do their workdo their work

They also need to get They also need to get rid of waste rid of waste

The circulatory system The circulatory system is what allows the cell is what allows the cell to exchange oxygen to exchange oxygen and nutrients and and nutrients and waste waste (it’s the body’s (it’s the body’s transport system)transport system)

Overview cont.Overview cont. The circulatory The circulatory

system is made up system is made up of: blood, the heart, of: blood, the heart, blood vesselsblood vessels

Blood carries Blood carries substances to all substances to all parts of the bodyparts of the body

The heart pumps The heart pumps blood through a huge blood through a huge network of tubes network of tubes inside your body inside your body called called blood vesselsblood vessels

Blood VesselsBlood Vessels Think of blood vessels Think of blood vessels

like highways; like highways; they they are a network of are a network of channels that circulate channels that circulate blood through the blood through the entire body and help entire body and help keep the blood flowing keep the blood flowing to and from the heartto and from the heart

There are 3 different There are 3 different kinds of blood vessels: kinds of blood vessels: arteries, capilaries, arteries, capilaries, and veins (think – and veins (think – airplanes, cars and airplanes, cars and vans)vans)

ArteriesArteries

AArteries carry blood rteries carry blood AAWAY from the WAY from the heartheart

They are strong, They are strong, and and thick-walledthick-walled so so they are they are capable of capable of withstanding high withstanding high pressures exerted pressures exerted by blood as it’s by blood as it’s pumped by the pumped by the heartheart

CapillariesCapillaries Arteries branch into smaller Arteries branch into smaller

vessels called arteriolesvessels called arterioles, , which become smaller in which become smaller in diameter as they grow farther diameter as they grow farther away from the main vesselaway from the main vessel

CapillariesCapillaries are small blood are small blood vessels where the exchange vessels where the exchange of important substances and of important substances and waste occurs waste occurs

They are very thin They are very thin – only 1 – only 1 cell thick – cell thick – so it’s easy to so it’s easy to exchange materials between exchange materials between the blood and body cells the blood and body cells through diffusionthrough diffusion

They’re so small that red They’re so small that red blood cells move single-file blood cells move single-file through them, but they can through them, but they can expand if needed (when expand if needed (when exercising for example)exercising for example)

VeinsVeins After blood moves through After blood moves through

the capillaries, it enters the capillaries, it enters larger vessels called larger vessels called venules,venules, and then enters the and then enters the largest blood vessels called largest blood vessels called veinsveins. .

VeinsVeins carry oxygen-poor carry oxygen-poor blood (deoxygenated) back blood (deoxygenated) back to the heart to the heart (Your blood IS (Your blood IS NOT BLUE)NOT BLUE)

The walls of veins are The walls of veins are thinner than arteries thinner than arteries because there’s less because there’s less pressure from the heart’s pressure from the heart’s original pushing forceoriginal pushing force

*How can you tell if you’ve *How can you tell if you’ve cut a vein or an artery?cut a vein or an artery?

Draw the path that blood Draw the path that blood takes going away from, and takes going away from, and then back into your heart, then back into your heart, labeling each blood vessel labeling each blood vessel

that it travels throughthat it travels through

Brain BreakBrain Break

The HeartThe Heart This is a muscular This is a muscular

organ that is about organ that is about the size of your the size of your fistfist. It pumps . It pumps blood through your blood through your body body (pumps (pumps oxygenated blood oxygenated blood to the body, and to the body, and deoxygenated deoxygenated blood to the lungs)blood to the lungs)

It’s made of It’s made of cardiac muscle cardiac muscle tissuetissue

The Heart cont.The Heart cont. It’s divided into four It’s divided into four

compartments called compartments called chamberschambers

The two on the top – left and The two on the top – left and right right atriumatrium or or atriaatria – – receive receive blood that’s returning to the blood that’s returning to the heart. heart. Below the atria are the Below the atria are the ventricles, which pump blood ventricles, which pump blood away from the heartaway from the heart

A strong muscular wall A strong muscular wall separates the left and right separates the left and right side of the heartside of the heart

Valves separate the atria from Valves separate the atria from the ventricles and keep blood the ventricles and keep blood flowing in one directionflowing in one direction, and , and are also located between are also located between each ventricle and the large each ventricle and the large blood vessels that carry blood blood vessels that carry blood away from the heartaway from the heart

Brain BreakBrain Break

Draw and Label the Draw and Label the chambers of the chambers of the heartheart

How the heart beatsHow the heart beats The heart acts in two The heart acts in two

main phases:main phases: 11stst, , the atria fill with the atria fill with

blood. The atria blood. The atria contract, which fills the contract, which fills the ventricles with bloodventricles with blood

22ndnd, , the ventricles the ventricles contract to pump blood contract to pump blood out of the heart and into out of the heart and into the lungs, and forward the lungs, and forward into the bodyinto the body

Heart beat cont.Heart beat cont. A group of cells in the right A group of cells in the right

atrium, called the pacemaker atrium, called the pacemaker (or sinoatrial- SA- node) (or sinoatrial- SA- node) send send out signals that tell the heart out signals that tell the heart muscle to contractmuscle to contract. (each . (each year 600,000 pacemakers year 600,000 pacemakers are implanted into people – are implanted into people – the battery usually lasts 5 to the battery usually lasts 5 to 8 years and needs to be 8 years and needs to be monitored frequently) monitored frequently)

Your heart beats about 70 Your heart beats about 70 times a minutetimes a minute

To calculate your heart beat, To calculate your heart beat, find your pulse on your wrist find your pulse on your wrist below your thumb. Count the below your thumb. Count the number of beats you feel in number of beats you feel in 15 seconds, then multiply 15 seconds, then multiply that number by 4 (to get that number by 4 (to get beats per minute)beats per minute)

Blood PressureBlood Pressure Blood pressure is a Blood pressure is a

measure of how much measure of how much pressure is exerted against pressure is exerted against the vessel walls by the the vessel walls by the bloodblood and can give and can give information about the information about the condition of the arteriescondition of the arteries

The contraction of the The contraction of the heart heart (systolic pressure) (systolic pressure) is is when your blood pressure when your blood pressure is at its highest pointis at its highest point

The relaxation of the heart The relaxation of the heart (diastolic pressure) (diastolic pressure) is the is the lowest pointlowest point

Anyone know ideal blood Anyone know ideal blood pressure?pressure?

Blood flow in the bodyBlood flow in the body Blood flows in 2 loops Blood flows in 2 loops – – First, the right side pumps First, the right side pumps

deoxygenated blood from the deoxygenated blood from the heart to the lungs and then heart to the lungs and then back to the heart. back to the heart.

Then, the left side pumps Then, the left side pumps oxygenated blood in another oxygenated blood in another loop from the heart through the loop from the heart through the body and back.body and back.

A detailed list of bloods path:A detailed list of bloods path:Superior and inferior vena cava –Superior and inferior vena cava –

right atrium – through the AV right atrium – through the AV (or tricuspid valve) (or tricuspid valve) -right -right ventricle – through the ventricle – through the semilunar valve - pulmonary semilunar valve - pulmonary arteries arteries (away from heart) (away from heart) – – lungs – pulmonary veins lungs – pulmonary veins (returning to heart) (returning to heart) – left – left atrium – left AV valve - left atrium – left AV valve - left ventricle – aorta – bodyventricle – aorta – body

To the lungs and backTo the lungs and back When blood from the body flows When blood from the body flows

into the right atrium, it’s low on into the right atrium, it’s low on oxygen and high in carbon dioxide oxygen and high in carbon dioxide (this blood is not blue, it’s dark (this blood is not blue, it’s dark red)red)

The blood flows from the right The blood flows from the right atrium into the right ventricle and atrium into the right ventricle and is pumped into the pulmonary is pumped into the pulmonary arteries that lead to the lungsarteries that lead to the lungs

The blood flows into capillaries in The blood flows into capillaries in the lungs that are in close contact the lungs that are in close contact with the air that enters the lungswith the air that enters the lungs

The air in the lungs has more The air in the lungs has more oxygen than the blood in the oxygen than the blood in the capillaries, so it diffuses into the capillaries, so it diffuses into the blood while carbon dioxide blood while carbon dioxide diffuses in the opposite direction, diffuses in the opposite direction, into the lungs. into the lungs.

The newly oxygenated blood goes The newly oxygenated blood goes to the left atrium of the heart to to the left atrium of the heart to be pumped out to the bodybe pumped out to the body

To the body and backTo the body and back The left atrium fills with The left atrium fills with

oxygenated blood from the oxygenated blood from the lungs, which begins the second lungs, which begins the second looploop

The blood moves from the left The blood moves from the left atrium into the left ventricle, atrium into the left ventricle, which pumps the blood into the which pumps the blood into the largest artery in the body called largest artery in the body called the aortathe aorta

Blood flows into the capillaries Blood flows into the capillaries that branch throughout the that branch throughout the body, which are in close contact body, which are in close contact with body cellswith body cells

Oxygen is released from the Oxygen is released from the blood into the body cells by blood into the body cells by diffusion and carbon dioxide diffusion and carbon dioxide moves from the cells to the moves from the cells to the blood by diffusionblood by diffusion

The deoxygenated blood then The deoxygenated blood then flows back to the right atrium flows back to the right atrium through veinsthrough veins

Heart simulation activity AND Heart simulation activity AND THEN drawing activityTHEN drawing activity

Brain BreakBrain Break

Blood ComponentsBlood Components Blood is made of plasma, red Blood is made of plasma, red

and white blood cells, and and white blood cells, and plateletsplatelets

PlasmaPlasma is a clear, yellowish is a clear, yellowish fluid part of the blood (makes fluid part of the blood (makes up more than 50% of the up more than 50% of the blood)blood)

90% of plasma is water, and 90% of plasma is water, and the rest is dissolved materialthe rest is dissolved material

Plasma carries glucose, fats, Plasma carries glucose, fats, vitamins, minerals, vitamins, minerals, hormones, and waste hormones, and waste productsproducts

Plasma is made of proteins Plasma is made of proteins (one of your macromolecules) (one of your macromolecules) that help regulate water, fight that help regulate water, fight disease, and form blood clotsdisease, and form blood clots

Blood components cont.Blood components cont. Red blood cells carry Red blood cells carry

oxygen to all of the oxygen to all of the cells in the bodycells in the body

Made in the bone Made in the bone marrowmarrow

They only live about They only live about 120 days120 days

Made mostly of an Made mostly of an iron-containing protein iron-containing protein called hemoglobin (it’s called hemoglobin (it’s what gives blood its what gives blood its taste)taste)

PlateletsPlatelets Platelets are cell fragments Platelets are cell fragments

that help form blood clotsthat help form blood clots If a blood vessel is cut, If a blood vessel is cut,

then the platelets stick to then the platelets stick to the vessel at the site of the the vessel at the site of the wound then release wound then release chemicals that produce a chemicals that produce a protein called fibrinprotein called fibrin

Fibrin weaves fibers across Fibrin weaves fibers across the cut the cut

These fibers trap blood These fibers trap blood platelets and red blood platelets and red blood cells, which forms a blood cells, which forms a blood clotclot

White blood cellsWhite blood cells White blood cells are the White blood cells are the

body’s disease fightersbody’s disease fighters Also made in the bone Also made in the bone

marrowmarrow Some recognize disease-Some recognize disease-

causing organisms (like causing organisms (like bacteria) and alert the bacteria) and alert the body, while others surround body, while others surround and fight themand fight them

There are fewer of these There are fewer of these than red blood cells – about than red blood cells – about one for every 500 to 1000 one for every 500 to 1000

They live longer then red They live longer then red blood cells; they can live blood cells; they can live for many months, or even for many months, or even yearsyears

Blood GroupsBlood Groups

There are marker There are marker molecules attached molecules attached to red blood cellsto red blood cells (called blood (called blood groups); groups); they they determine blood determine blood typetype

Blood groups cont.Blood groups cont. There are 4 types of blood – There are 4 types of blood –

A, B, AB, and OA, B, AB, and O If you ever need a blood If you ever need a blood

transfusion, you can only transfusion, you can only receive certain blood types receive certain blood types because plasma contains because plasma contains proteins called antibodies proteins called antibodies that recognize red blood that recognize red blood cells with foreign markers cells with foreign markers and cause those cells to and cause those cells to clump togetherclump together

Ex – if you have blood type Ex – if you have blood type B, your blood contains B, your blood contains antibodies that cause cells antibodies that cause cells with A marker to clump; with A marker to clump; this can block blood flowthis can block blood flow

O is the universal donorO is the universal donor AB is the universal receiverAB is the universal receiver

Blood groups cont.Blood groups cont. Rh factor is another marker Rh factor is another marker

found on the surface of red blood found on the surface of red blood cellscells

If someone with Rh-negative If someone with Rh-negative blood (no Rh factor) receives a blood (no Rh factor) receives a transfusion of Rh-positive blood transfusion of Rh-positive blood that has the Rh marker, it can that has the Rh marker, it can result in clumping of red blood result in clumping of red blood cells because of the antibodies cells because of the antibodies against Rh-positive cellsagainst Rh-positive cells

It can cause complications during It can cause complications during some pregnancies (if the Rh-some pregnancies (if the Rh-positive blood of a fetus mixes positive blood of a fetus mixes with the mothers Rh-negative with the mothers Rh-negative blood, the mother will make anti-blood, the mother will make anti-Rh antibodies. If the mother Rh antibodies. If the mother becomes pregnant again, these becomes pregnant again, these antibodies can cross the placenta antibodies can cross the placenta dn destroy red blood cells if the dn destroy red blood cells if the fetus has Rh-positive blood)fetus has Rh-positive blood)

*may have been a problem for *may have been a problem for Ann BoelynAnn Boelyn

Circulatory system disordersCirculatory system disorders AtherosclerosisAtherosclerosis – blocked – blocked

arteries caused by blood clots or arteries caused by blood clots or fat deposits which reduce the fat deposits which reduce the flow of oxygen and nutrient-rich flow of oxygen and nutrient-rich blood traveling through the blood traveling through the arteries. arteries.

The heart has to work even The heart has to work even harder to pump blood and harder to pump blood and vessels can burstvessels can burst

Can lead to a heart attack or Can lead to a heart attack or strokestroke

Heart attacks occur when blood Heart attacks occur when blood doesn’t reach the heart muscledoesn’t reach the heart muscle

Strokes are caused when clots Strokes are caused when clots form in the blood vessels that form in the blood vessels that supply oxygen to the brain, supply oxygen to the brain, which can lead to ruptured which can lead to ruptured blood vessels and internal blood vessels and internal bleeding (parts of the brain die bleeding (parts of the brain die because brain cells are deprived because brain cells are deprived of oxygen)of oxygen)