The Cardiovascular System
CrashCourse Circulatory System Video
https://www.youtube.com/watch?v=9fxm85Fy4sQ
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37–1 The Circulatory System
Circulatory System Introduction:
The circulatory system and respiratory system work together to supply cells with the nutrients and oxygen they need to stay alive.
Functions of the Circulatory System
Cardiovascular System
Humans and other vertebrates have closed circulatory systems, meaning that the blood is contained within a system of vessels (tubes).
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The circulatory system as a system of tubes with a pump (heart) and valves to ensure one-way flow of blood
Describe the double circulation in terms of:
1. a low pressure circulation to the lungs and
2. a high pressure circulation to the body tissues
High Pressure
Functions of the Circulatory System
Circulatory Introduction
The human circulatory system consists of:
• the heart
• blood vessels
• blood
IB Assessment Statement
Draw and Label a diagram of the heart showing the four chambers associated blood vessels, valves and the route of the blood through the heart. Know the relative thickness of the four chambers.
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The Heart
The Heart
The heart is a double pump:
1. The right side of the heart pumps blood to the lungs
2. The left side of the heart pumps blood to the rest of the body.
The Heart
The Heart
The walls of the heart are composed of cardiac muscle.
Contraction of cardiac muscle is myogenic.
• Myogenic means that it can contract on its own it does not need to be stimulated by a nerve.
The Heart
The Heart
The heart is enclosed in a protective sac of tissue.
In the walls of the heart, two layers of tissue form around a thick layer of muscle.
Contractions of the layer of muscle pump blood.
The Heart – Coronary arteries
– There are many capillaries in the muscular wall of the heart.
These are called the coronary arteries.
The Heart – Coronary arteries
The function of the coronary arteries are listed below:
Bring nutrients to heart muscle
Bring oxygen for aerobic cell respiration, which provides heart tissue with energy necessary for heart contraction.
Remove waste products (CO2) from heart muscle
IB LEARNING OBJECTIVE
State the function of the coronary arteries
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Coronary Heart Disease
If the coronary arteries or veins become blocked, the heart muscles become:
deprived of oxygen and sugar
And poisonous waste products build up
Resulting in a HEART ATTACK.
Coronary Heart Disease
Blockage of coronary arteries is called coronary heart disease.
People at Risk for Coronary Heart Disease
Smoking Cigarettes – nicotine damages the circulatory system
Diet – a diet high in saturated fat, salt and cholesterol
Obesity – Being overweight
Stress – unmanageable or long term stress
Genes – Some people inherit genes that make it more likely
A doctor can determine if you have a block coronary arteries by doing an Angiogram.
It gives a picture of the coronary arteries.
If you have a blocked coronary artery or veins, you can have surgery.
Coronary Bypass Surgery
In Coronary Bypass Surgery a blood vessel is removed from one part of the body and sewn in the heart muscle
Preventing Heart Disease
Regular Exercise
Healthy eating
Maintaining weight
Heart Attack Video
http://www.hhmi.org/biointeractive/how-heart-attack-occurs
IB LEARNING OBJECTIVE:
Describe the relative thickness of the four chambers.
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The Heart
Structures of the Heart
The Heart
Large vein that brings oxygen-poor blood from the upper part of the body to the right atrium
Right Atrium
Superior Vena Cava:
The Heart
Bring oxygen-rich blood from each of the lungs to the left atrium
Left Atrium
Pulmonary Veins: Pulmonary
Veins:
The Heart
Prevents blood from flowing back into the right ventricle after it has entered the pulmonary artery.
Right Atrium
Pulmonary ArteriesSemilunar Valves:
The Heart
Prevents blood from flowing back into the right atrium after it has entered the right ventricle
Right Atrium
Atrioventricle (Tricuspid) Valve:
The Heart
Vein that brings oxygen-poor blood from the lower part of the body to the right atrium.
Right Atrium
Inferior Vena Cava:
The Heart
Atrioventricle (Bicuspid) Valve: Prevents blood from flowing back into the left atrium after it has entered the left ventricle
Left Atrium
Left Ventricle
The Heart
Semilunar Valve: Prevents blood from flowing back into the left ventricle after it has entered the aorta
Left Atrium
Left Ventricle
Aorta
The Heart
Bring oxygen-poor blood to the right or left lung
Pulmonary Arteries:
The Heart
Brings oxygen-rich blood from the left ventricle to the body
Aorta:
The Heart
The septum divides the right side of the heart from the left.
It prevents the mixing of oxygen-poor and oxygen-rich blood.
The Heart
The heart has four chambers—two atria and two ventricles.
There are two chambers on each side of the septum.
The upper chamber, which receives the blood, is the atrium.
The lower chamber, which pumps blood out of the heart, is the ventricle.
Atria vs. Ventricles
Both Atria have thinner walls than the ventricles, because they only need to pump blood to the ventricles.
Left ventricle vs. right ventricle
– Left Ventricle wall is thicker than the right ventricle, because it pumps blood through the arteries to all the tissues in the body
–Right Ventricle wall is thinner and less muscular than the left ventricle because it is only pumps blood to the lungs
Left vs. Right Ventricle Venn Diagram
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IB LEARNING OBJECTIVE
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing the of valves.
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Flow of blood tutorial :
http://www.kscience.co.uk/animations/blood_system.swf
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The Heart
Circulation Through the Heart
Blood enters the heart through the right and left atria.
As the heart contracts, blood flows into the ventricles and then out from the ventricles to either the body or the lungs.
The Heart
There are flaps of connective tissue called valves between the atria and the ventricles.
When the ventricles contract, the valves close, which prevents blood from flowing back into the atria.
The Heart
At the exits from the right and left ventricles, valves prevent blood that flows out of the heart from flowing back in.
Blood leaves the left ventricle, and enters the aorta.
The aorta is one of the blood vessels that carry the blood through the body and back to the heart.
The Heart
Circulation Through the Body
The heart functions as two separate pumps.
The Heart
Pulmonary Circulation
One pathway circulates blood between the heart and the lungs.
This pathway is known as pulmonary circulation.
In the lungs, carbon dioxide leaves the blood and oxygen is absorbed. The oxygen-rich blood returns to the heart.
The Heart
Systemic Circulation
The second pathway circulates blood between the heart and the rest of the body.
This pathway is called systemic circulation.
After returning from the lungs, the oxygen-rich blood is pumped to the rest of the body.
The Heart
Circulation of Blood through the Body
Capillaries of head and arms
Superior vena cava Aorta
Pulmonary veinCapillaries of
right lungs
Inferior vena cava
Capillaries of abdominal organs and legs
Capillaries of left lung
Pulmonary artery
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Cardiac Cycle More detailsStep 1
Diastole
The heart muscle is relaxed this is called diastole.
There is no pressure in the heart chambers.
Blood tries to flow back into the heart but closes the semi-lunar valves.
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Cardiac Cycle More detailsStep 2
Diastole
Both atria fill with blood returning to the heart in the veins.
The right atria fills with blood returning in the vena cava from the body tissues (deoxygenated).
The atrio-ventricular valves are still closed and the atria fill up.
When the pressure in the atria is greater than the pressure in the ventricles the atrio-ventricular valves will open.
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Cardiac Cycle More detailsStep 3
Late Diastole
In this diagram the heart is still relaxed (diastole).
The pressure of blood returning to the heart and filling the atria is now high enough to open the atrio-ventricular valves.
The pressure in the atria is greater than the pressure in the ventricles.
Atrio-ventricular valves open
Ventricles begin to fill with blood..
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Cardiac Cycle More detailsStep 4
Atrial systole
Both atria contract together (see control of heart rate)
The muscles of the atria contract.
volume of the atria reduces.
Pressure of blood increases
Blood flow into the ventricle, filling this chamber and causing the ventricle wall to stretch...
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Cardiac Cycle More detailsStep 6
Ventricular Systole
The ventricle contracts (systole)
The pressure increases in the ventricle
The atrio-ventricular valve closes
The pressure rises further
Pressure in the ventricle is greater than the artery, semi-lunar valve opens
Blood pulses into the arteries
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IB LEARNING OBJECTIVE:
Describe the relationship between the structure and function of blood vessels. [6]
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Blood Vessels
Blood Vessels Introduction
As blood flows through the circulatory system, it moves through three types of blood vessels:
• arteries
• capillaries
• veins
Blood Vessels
Arteries
Large vessels that carry blood from the heart to the tissues of the body are called arteries.
Except for the pulmonary arteries, all arteries carry oxygen-rich blood.
Pulmonary artery carries oxygen poor blood from the right side of the heart to the left side
Arteries have thick walls.
Four parts of the artery:
1. a narrow central tube
2. A smooth lining so no obstruction to blood flow will occur
3. A thick layer of muscles and elastic fibers
4. A thick outer wall.
Thick outer wallThick outer wall
Smooth lining
Thick muscular layer
Thick outer wall
Thick muscular layer
Thick outer wall
Smooth lining
Thick muscular layer
Thick outer wall
Smooth lining
Thick muscular layer
Thick outer wall
Blood Vessels
Capillaries
The smallest of the blood vessels are the capillaries.
Their walls are only one cell thick, and most are narrow.
The capillaries bring nutrients and oxygen to the tissues and absorb carbon dioxide and other waste products from them.
Blood Vessels
Blood Vessels
Veins
Blood vessels that carry blood back to the heart are veins.
Veins have thinner walls than arteries.
Four parts to the structure of Veins:
1. Wide central tube
2. Thin layer of muscle
3. Valves
4. Thin outer wall
Thin Outer
Wall
Thin layer
Of muscle
Smooth liningSmooth lining
Thin layer
Of muscle
Smooth lining
Thin Outer
Wall
Thin layer
Of muscle
Smooth lining
Thin Outer
Wall
Thin layer
Of muscle
Smooth lining
Blood Vessels
Large veins contain valves that keep blood moving toward the heart.
Valve open
Valve closed
Valves closed
Veins vs. Arteries Venn Diagram
IB LEARNING OBJECTIVE
Draw and Label a diagram of the heart showing the four chambers associated blood vessels, valves and the route of the blood through the heart (4 Points)
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Virtual Heart Dissection:
http://www.gwc.maricopa.edu/class/bio202/cyberheart/anthrt.htm
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