Open Vs Closed Circulatory Open Vs Closed Circulatory SystemSystem

OpenOpen

Open ended vessel which blood Open ended vessel which blood leavesleaves

Blood flows around cellsBlood flows around cells

Enters heart through openingsEnters heart through openings

ClosedClosed

Blood remains in vesselsBlood remains in vessels

Materials exchanged by diffusionMaterials exchanged by diffusion

More efficient then open system, More efficient then open system, Faster and flow can be Faster and flow can be increased/decreasedincreased/decreased

Blood VesselsBlood Vessels3 main types3 main types

1. 1. ArteriesArteries (A for Away from heart) (A for Away from heart)divide into smaller vessels- Arteriolesdivide into smaller vessels- Arterioles

2. 2. VeinsVeins (to heart) (to heart)divide into smaller veins- Venulesdivide into smaller veins- Venules

3. 3. CapillariesCapillariestiny vessel (1 cell in thickness), link tiny vessel (1 cell in thickness), link arteries & veinsarteries & veins

Arteries Vs VeinsArteries Vs Veins

What have they both got in common? What is different?

Arteries Vs VeinsArteries Vs Veins

Both have the same 3 layers.Both have the same 3 layers.

Main difference is in the middle layer.Main difference is in the middle layer. 3 layers3 layers

1.1. Outer, is tough, made of protein called Outer, is tough, made of protein called collagen which prevents wall from over collagen which prevents wall from over expanding.expanding.

2.2. Middle, is muscle and elastic, it can alter the Middle, is muscle and elastic, it can alter the size of the vesselsize of the vessel

3.3. Inner, are living cells called endothelium.Inner, are living cells called endothelium.

ValvesValves Blood pressure is the force blood applies Blood pressure is the force blood applies

against the wall of a blood vessel.against the wall of a blood vessel. Blood pressure is highest in arteries, this Blood pressure is highest in arteries, this

causes the arteries to expand, which causes the arteries to expand, which causes our pulse.causes our pulse.

Pressure in veins is very weak. Ordinary Pressure in veins is very weak. Ordinary muscles help push the blood by contracting muscles help push the blood by contracting and squeezing to return blood to the heart.and squeezing to return blood to the heart.

Because pressure is low, must prevent Because pressure is low, must prevent backflowbackflow

Valves control direction of blood flowValves control direction of blood flow

ArteryArtery VeinVein

Carries blood away Carries blood away from heartfrom heart

Carries blood to heartCarries blood to heart

Blood under high Blood under high pressurepressure

Blood under low Blood under low pressurepressure

Thick wallsThick walls Thin wallsThin walls

Small LumenSmall Lumen Large LumenLarge Lumen

Blood flows in pulseBlood flows in pulse No pulseNo pulse

Blood rich in oxygenBlood rich in oxygen Blood low in oxygenBlood low in oxygen

Valves absentValves absent Valves presentValves present

CapillariesCapillaries

Tiny, branched vesselsTiny, branched vessels Walls are permeable, allow materials Walls are permeable, allow materials

to move across the wallsto move across the walls 100,000 km 100,000 km

The HeartThe Heart

Made of cardiac (slow to fatigue) Made of cardiac (slow to fatigue) muscle, surrounded by a double muscle, surrounded by a double membrane called Pericardium.membrane called Pericardium.

It contracts 100,000 times a dayIt contracts 100,000 times a day Pumps 5-20 litres of blood per Pumps 5-20 litres of blood per

minuteminute Why such a difference? 5-20Why such a difference? 5-20

Structure of the HeartStructure of the Heart Divided into 2 side by a wall called Septum.Divided into 2 side by a wall called Septum.

4 chambers, 4 chambers,

2 upper = Atria, 2 lower = Ventricles2 upper = Atria, 2 lower = Ventricles Atria & ventricles are separated by valvesAtria & ventricles are separated by valves These valves are held in place by tendonsThese valves are held in place by tendons These tendons are held in place by Papillary These tendons are held in place by Papillary

Muscles.Muscles.

Valve on right has 3 flaps, tricuspid valveValve on right has 3 flaps, tricuspid valve Valve on left has 2 flaps, bicuspid valveValve on left has 2 flaps, bicuspid valve Semilunar valves prevent blood returning to Semilunar valves prevent blood returning to

heart heart

Left atriumRight atrium

Left ventricle

Right ventricle

Tricuspid valve

Bicuspid valveTendon

Papillary Muscle

SeptumCardiac Muscle

Pericardium

Semilunar valve Semilunar valve

Pacemaker

Superior vena cava

Inferiorvena cava

Pulmonary artery

Pulmonary vein

Aorta

Blood flow in the heartBlood flow in the heart

Step 1Step 1 Deoxygenated blood enters the right Deoxygenated blood enters the right

atrium through 2 venae cavae.atrium through 2 venae cavae.

Superior - head, arms, chest.Superior - head, arms, chest.

Inferior – Lower part of body.Inferior – Lower part of body. The right atrium contracts forcing blood The right atrium contracts forcing blood

into right ventricleinto right ventricle The venae cavae close to prevent The venae cavae close to prevent

backflow backflow

Blood flow in the heartBlood flow in the heart

Step 2Step 2 When the right ventricle contracts When the right ventricle contracts

the tricuspid valve is forced closedthe tricuspid valve is forced closed Blood is then forced out of the heart Blood is then forced out of the heart

and into the lungs through the and into the lungs through the semilunar valve in the pulmonary semilunar valve in the pulmonary artery.artery.

Blood flow in the HeartBlood flow in the Heart

Stage 3 Stage 3 Oxygenated blood returns to the Oxygenated blood returns to the

heart from the lungs and enters the heart from the lungs and enters the left atrium through the pulmonary left atrium through the pulmonary veins (only vein to ever carry oxygen veins (only vein to ever carry oxygen rich blood)rich blood)

Pumped through bicuspid valve into Pumped through bicuspid valve into the left ventriclethe left ventricle

Blood flow in the heartBlood flow in the heart

Stage 4Stage 4 When the left ventricle contracts the When the left ventricle contracts the

bicuspid valve closes.bicuspid valve closes. Blood is pumped out of the heart Blood is pumped out of the heart

through the semilunar valve in the through the semilunar valve in the aortaaorta

When the ventricles relax these When the ventricles relax these valves close to stop backflowvalves close to stop backflow

Double CirculationDouble Circulation Heart is really a double pump. The 2 sides Heart is really a double pump. The 2 sides

of the heart are divided by the septum. of the heart are divided by the septum. Why is this necessary?Why is this necessary? Answer=Answer=

Hence humans have a 2-circuit circulatory Hence humans have a 2-circuit circulatory system.system.

The Pulmonary Circuit & The Systemic The Pulmonary Circuit & The Systemic CircuitCircuit

Double CirculationDouble Circulation

Pulmonary circuitPulmonary circuit

Right ventricle pumps de-oxygenated Right ventricle pumps de-oxygenated blood around the pulmonary circuit.blood around the pulmonary circuit.

This circuit is short so the walls of the This circuit is short so the walls of the ventricle are thinventricle are thin

Double CirculationDouble Circulation

Systemic CircuitSystemic Circuit

The Left ventricle pumps oxygenated The Left ventricle pumps oxygenated blood to head, arms, trunk and legs.blood to head, arms, trunk and legs.

This is a much longer route so the This is a much longer route so the walls are much thicker and stronger.walls are much thicker and stronger.

Double Vs Single CirculationDouble Vs Single Circulation

Allows oxygen rich and poor blood to Allows oxygen rich and poor blood to be kept separate.be kept separate.

Ensures the blood pressure is high Ensures the blood pressure is high

enough to reach all parts of the body.enough to reach all parts of the body.

Single circulation system can only Single circulation system can only produce low pressure, this restricts produce low pressure, this restricts activities of animal i.e. wormactivities of animal i.e. worm

Blood supply to the Heart Blood supply to the Heart itselfitself

supplied by the coronary arteriessupplied by the coronary arteries

These are connected by the aortaThese are connected by the aorta

coronary veins drain blood into the right coronary veins drain blood into the right atriumatrium

Blockage of the coronary arteries is a Blockage of the coronary arteries is a common cause for heart attackscommon cause for heart attacks

What Controls the What Controls the HeartbeatHeartbeat

The pacemaker or SA (Sino-atrial node), The pacemaker or SA (Sino-atrial node), located in the wall at the top of the right located in the wall at the top of the right atriumatrium

It sends out a regular electrical impulse It sends out a regular electrical impulse which causes the atria to contract, which causes the atria to contract, followed by the ventricles.followed by the ventricles.

Frequency of these impulses are controlled Frequency of these impulses are controlled by the brain & can speed up or slow down.by the brain & can speed up or slow down.

Pacemaker

Superior vena cava

Inferiorvena cava

Pulmonary artery Pulmonary vein

Aorta

Stages of heartbeatStages of heartbeat

DiastoleDiastole = Chambers relax = Chambers relax SystoleSystole = Chambers contract = Chambers contract

1.1. Blood enters heart (Atrial Diastole)Blood enters heart (Atrial Diastole)both Ventricles & Atria are relaxed. All both Ventricles & Atria are relaxed. All valves are closed.valves are closed.

Stages of HeartbeatStages of Heartbeat

PM cause atria to PM cause atria to contract (how?), this contract (how?), this pumps blood into pumps blood into ventricle. ventricle.

The tri & bi-cuspid The tri & bi-cuspid valves open while the valves open while the venae cava & venae cava & pulmonary veins close. pulmonary veins close. Semi-lunar valves Semi-lunar valves remain closed. remain closed.

2.2.Blood is pumped from atria to Blood is pumped from atria to ventriclesventricles

(Atrial systole)(Atrial systole)

Stages of heartbeatStages of heartbeat33. . Blood leaves the heart (Ventricular Systole)Blood leaves the heart (Ventricular Systole)

Atria relax, impulses from AV (atrio-ventricular) Atria relax, impulses from AV (atrio-ventricular) nodes cause ventricles to contract. This forces nodes cause ventricles to contract. This forces blood out through the pulmonary artery & Aortablood out through the pulmonary artery & Aorta

The pressure forces open The pressure forces open semi-lunar valves & semi-lunar valves & closes the tri & bi-cuspid closes the tri & bi-cuspid valvesvalves

Ventricles relax, closing Ventricles relax, closing the semi-lunar valves.the semi-lunar valves.

Sound of HeartbeatSound of Heartbeat

““Lub-dub” soundLub-dub” sound

Caused by valves being forced shutCaused by valves being forced shut

Lub due to bi & tri-cuspid valves closingLub due to bi & tri-cuspid valves closing

Dub due to semi-lunar valves snapping Dub due to semi-lunar valves snapping shutshut

PulsePulse When left (thick) ventricle contracts, When left (thick) ventricle contracts,

pressure of blood forced in the aorta pressure of blood forced in the aorta causes it to expand & then contractcauses it to expand & then contract

This forms a wave down the arteries This forms a wave down the arteries called pulsecalled pulse

Average adult pulse rate is 72 Average adult pulse rate is 72 beats/minbeats/min

Most people between 60-100Most people between 60-100

Blood PressureBlood Pressure

This is the force exerted by the blood This is the force exerted by the blood against the walls of the blood vesselsagainst the walls of the blood vessels

Human blood pressure is measured by Human blood pressure is measured by finding the amount of pressure needed finding the amount of pressure needed to stop the flow of bloodto stop the flow of blood

This produces 2 readings This produces 2 readings

1. When there is a pulse 2. When no pulse1. When there is a pulse 2. When no pulse

Blood PressureBlood Pressure Typical blood pressure in adults is Typical blood pressure in adults is

120/80 mm of mercury. These values 120/80 mm of mercury. These values rise with age.rise with age.

If the lower value goes over 95 mm of Hg If the lower value goes over 95 mm of Hg the person suffers from high blood the person suffers from high blood pressurepressure

High blood pressure is caused by High blood pressure is caused by blockages in arteries.blockages in arteries.

Effects of smoking on HeartEffects of smoking on Heart

Tabacco contains 400 harmful chemicals, Tabacco contains 400 harmful chemicals, including nicotine (more addictive then including nicotine (more addictive then heroin)heroin)

Nicotine causes increased heart rate & blood Nicotine causes increased heart rate & blood pressurepressure

Carbon monoxide reduces O2 carried by Carbon monoxide reduces O2 carried by bloodblood

In Ireland 7000 people a yr die form smokingIn Ireland 7000 people a yr die form smoking

Effects of exercise on HeartEffects of exercise on Heart When we exercise our muscles get bigger When we exercise our muscles get bigger

& stronger this is the same for our heart& stronger this is the same for our heart

Exercise improves circulation and Exercise improves circulation and reduces body weightreduces body weight

Most beneficial exercise is aerobic Most beneficial exercise is aerobic exercise e.g. Walking, jogging, running, exercise e.g. Walking, jogging, running, swimming and Dancing so get your feet swimming and Dancing so get your feet moving.moving.

Effects of Diet on HeartEffects of Diet on Heart 3 main factors = salt, fat & being 3 main factors = salt, fat & being

overweightoverweight

Harmful fats found in red meat & dairy, Harmful fats found in red meat & dairy, they contain Cholesterol which forms they contain Cholesterol which forms blockagesblockages

1 packet of processed foods contains your 1 packet of processed foods contains your entire days intake of saltentire days intake of salt

Obesity causes high blood pressure & heart Obesity causes high blood pressure & heart attacksattacks