UNIT 11: Cardiovascular System Notes

Cells → Tissues → Organs → Organ Systems → An Organism

Cells are made of atoms. The six most important elements for life are: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous and Sulfur. These six elements make up 99% of the mass of the human body.

Your body is a collection of systems that must work together in order to maintain homeostasis. Each separate organ system cannot work independently and relies on many other organ systems to work properly. If one organ system is not working as it should, your other systems can be affected.

I. The Cardiovascular System

Small But Mighty! – Red blood cells are very small, very important for your body, and are donut-shaped. Your body makes about 200 billion new red blood cells every day.

Cardiovascular System: A collection of organs that transport blood to and from your body’s cells.- “cardio” = heart & “vascular” = vessel- The cardiovascular system is made of 3 parts: Blood, Heart, and Blood Vessels

Heart: The pump that drives the cardiovascular system. (your heart beats about 100,800 times per day)

A. Additional Functions of the Cardiovascular System1. Transport Materials:

∙ Gases: Oxygen (O2) is transported from the lungs to the cells. Carbon Dioxide (CO2) – a waste product is transported from the cells to the lungs.

∙ Nutrients to Other Cells: Glucose (C6H12O6), a simple sugar used to produce ATP during Cellular Respiration, it is transported throughout the body by the cardiovascular system. Immediately after digestion, glucose is transported to the liver. The liver maintains a constant level of glucose in the blood.

∙ Waste from Cells: Ammonia is produced as a result of protein digestion. It is transported to the liver where it is converted to less toxic urea. Urea is then transported to the kidneys for excretion in the urine.

∙ Hormones: Numerous hormones that help maintain constant internal conditions are transported by the cardiovascular system.

2. Contains cells that fight infection.3. Helps stabilize the pH (acidity) and ionic concentrations of body fluids.4. Helps maintain body temperature by transporting heat.

B. What is Blood?1. The human body contains about 5 Liters of blood.2. Blood: A connective tissue made up of two types of cells (Red & White blood

cells), cell parts, and plasma.3. Plasma: The fluid part of blood that is a mixture of water, minerals, nutrients,

sugars, proteins, and other substances. (red blood cells, white blood cells, and platelets float in the plasma)

4. Red Blood Cells (RBCs) - Erythrocytes- Red blood cells are the most abundant cells in blood. They supply your

cells with oxygen.- Hemoglobin: The protein in RBCs that attaches to oxygen so that oxygen

can be carried through the body. (hemoglobin gives RBCs their red color)- The shape of RBCs (donut-shaped) gives them a large amount of surface

area for absorbing and releasing oxygen.- RBCs are made in bone marrow. Before RBCs enter the bloodstream,

they lose their nuclease and other organelles… and cannot replace worn-out parts. RBCs therefore can live only about 4 months.

5. White Blood Cells (WBCs) - Leukocytes- Pathogens: An agent that causes a disease (bacteria, viruses, and other

microscopic particles).- White blood cells help you stay healthy by destroying pathogens and

helping clean wounds.- WBCs fight pathogens in several ways.

∙ Some squeeze out of vessels and move around in tissue, searching for pathogens – and then engulf them.

∙ Some WBCs release chemicals called antibodies that help destroy pathogens.

∙ Antibody: A special protein that can recognize specific pathogens.- WBCs also engulf dead or damaged body cells.- WBCs are made in bone marrow.

6. Platelets- Platelet: A cell fragment that helps clot blood. (only last 5-10 days)- Platelets are large cells in bone marrow that “pinch” off fragments of

themselves, which enter the blood.- Whey you cut yourself, you bleed because blood vessels have been

opened. As soon as bleeding occurs, platelets begin to clump together in the damaged area and from a plug that helps reduce blood loss.

- Platelets also release a variety of chemicals that react with proteins in the plasma and cause tiny fibers to form = blood clot.

C. Have a Heart1. Your heart is a muscular organ about the size of your fist in your chest cavity

between your lungs. It is made up of cardiac tissue – an involuntary muscle.2. The heart pumps oxygen-poor blood to the lungs and oxygen-rich blood to the body. 3. Your heart is divided into 2 sides and 4 chambers.

- Atrium: An upper chamber of the heart. (one on the left & one on the right)- Ventricle: A lower chamber of the heart. (one on the left & one on the right)- Valve: Flaplike structures that are located between the atria and ventricles

and also where large arteries are attached to the heart.∙ Valves open and close and prevent blood from going backward.

- The lub-dub, lub-dub sound that a beating heart makes is caused by the closing of the valves.

4. The flow of Blood Through the Heart- Blood enters the atria first. The left atrium receives oxygen-rich blood

from the lungs & the right atrium receives oxygen-poor blood from the body. When the atria contract, blood is squeezed into the ventricles. While the atria relax, the ventricles contract and push blood out of the heart. Blood from the right ventricle goes to the lungs. Blood from the left ventricle goes to the rest of the body.

D. Blood Vessels1. Blood Vessel: A hollow tube that transports blood. Blood travels throughout your

body in blood vessels. 2. There are 3 types of Blood Vessels:

a. Arteries: Blood vessels that direct blood away from the heart.- Arteries have thick elastic walls lined with smooth muscle- Blood leaves the heart at a high pressure, that is why the arteries

are made of thick muscle.b. Capillaries: smallest blood vessels in your body (10 times smaller than a

strand of hair)

- Capillary walls are only 1 cell thick! They allow nutrients, oxygen, and many other kinds of substances to diffuse easily through capillary walls.

- No cell in the body is more than 3 – 4 cells away from a capillary!!!c. Veins: Blood vessels that direct the blood back to the heart.

- Moving skeletal muscles helps push the blood back to the heart.d. Large arteries → small arteries → capillaries → small veins → large veins

3. If all the blood vessels in your body were strung together, the total length would be more than twice the circumference of the Earth!

E. Going with the Flow1. Pulmonary Circulation: The circulation of blood between your heart and lungs.

- The Pulmonary circulation is the portion of the cardiovascular system which transports oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. Oxygen deprived blood from the vena cava enters the right atrium of the heart and flows through the tricuspid valve into the right ventricle, from which it is pumped through the pulmonary semilunar valve into the pulmonary arteries which go to the lungs. Pulmonary veins return the now oxygen-rich blood to the heart, where it enters the left atrium before flowing through the mitral valve into the left ventricle. Then, oxygen-rich blood from the left ventricle is pumped out via the aorta, and on to the rest of the body.

2. Systemic Circulation: The circulation of blood between the heart and the body.- Systemic circulation is the portion of the cardiovascular system which

transports oxygenated blood away from the heart, to the rest of the body, and returns oxygen-depleted blood back to the heart. Systemic circulation is, distance-wise, much longer than pulmonary circulation, transporting blood to every part of the body.

3. Coronary circulation: Provides a blood supply to the heart. - As it provides oxygenated blood to the heart, it is by definition a part of the

systemic circulatory system.4. The Flow of Blood Through the Body (repeating cycle below)

- The heart pumps oxygen-rich blood from the left ventricle into arteries and then into capillaries. As blood travels through capillaries, it transports oxygen, nutrients, and water to the cells of the body. At the same time, waste materials and carbon dioxide are carried away.

- The right ventricle pumps oxygen-poor blood into arteries that lead to the lungs. These are the only arteries in the body that carry oxygen-poor blood.

- In the capillaries of the lungs, blood absorbs oxygen and releases carbon dioxide. Oxygen-rich blood travels through veins to the left atrium. These are the only veins in the body that carry oxygen-rich blood.

F. Blood Flows Under Pressure1. Pulse: Rhythmic change in blood pressure.

- Major Pulse Locations∙ Upper Limb: Axillary, Brachial, Radial & Ulnar∙ Lower limb: Femoral, Popliteal, Dorsalis pedis & Tibialis posterior ∙ Head/neck: Carotid pulse, Facial & Temporal ∙ Torso: Apical

2. Blood Pressure: The amount of force exerted by blood on the inside walls of a blood vessel.

- Blood pressure is reported in mm of Hg (mercury).- A blood pressure of 120 mm Hg means that the pressure on the vessel

walls is great enough to push a narrow column of mercury 120 mm high.

3. Normal blood pressure is about 120 / 80. - Systolic Pressure: The pressure inside large arteries when the ventricles

contract. (the first number is called the systolic pressure)- Diastolic Pressure: The pressure in the arteries when the ventricles relax.

(the second number is called the diastolic pressure)G. Exercise and Blood Flow

1. When you exercise, your muscles require much more oxygen and nutrients, so your heart beats faster to supply the needed materials to your body. Physical activity causes as much as 10 times more blood to be sent to the muscles than when your body is at rest.

2. During exercise, some organs do not need as much blood as the skeletal muscles.- More blood to: skeletal muscles, brain, heart, and lungs- Less blood to: kidneys and digestive system

H. Cardiovascular Problems1. Problems with the heart, blood vessels, or blood.2. Cardiovascular problems can be caused by smoking, cholesterol, stress, heredity…

- External Stimulus: Something outside of an animal’s body that causes the animal to react. (smoking, diet)

- Internal Stimulus: Something inside of an animal’s body (or cell) that causes the animal to react. (genetics)

3. Atherosclerosis: Occurs when fatty materials, such as cholesterol, build up on the inside of blood vessels. (Internal Stimulus)

- This is the leading cause of death in the US.- The fatty buildup causes the blood vessels to become narrower and less

elastic. When a major artery that supplies blood to the heart becomes blocked, a person has a heart attack.

4. Heart Disease (Cardiopathy): An “umbrella” word for many diseases of the heart.- Coronary heart disease, Cardiomyopathy, Cardiovascular disease, Ischaemic

heart disease, Heart failure, Hypertensive heart disease, Inflammatory heart disease & Valvular heart disease.

- Possible external stimuli would be smoking, fat intake, and stress. Possible internal stimuli would be genetics.

5. Hypoglycemia & Hyperglycemia- Hypoglycemia: The medical term for a state produced by a lower than

normal level of blood glucose. The term literally means "under-sweet blood" It can produce a variety of symptoms and effects but the principal problems arise from an inadequate supply of glucose to the brain, resulting in impairment of function (neuroglycopenia). Effects can range from mild dysphoria to more serious issues such as seizures, unconsciousness, and (rarely) permanent brain damage or death.

- Hyperglycemia: A condition in which an excessive amount of glucose circulates in the blood plasma. Chronic high levels can produce organ damage. The origin of the term is Greek: hyper-, meaning excessive; -glyc-, meaning sweet; and -emia, meaning "of the blood".

6. A Point About Pressure- Hypertension: An abnormally high blood pressure.

∙ Possible external stimuli would be diet with high salt intake, stress. Possible internal stimuli would be genetics.

∙ Dangerous because it overworks the heart and can weaken vessels and make them rupture.

- Stroke: Occurs when a blood vessel in the brain becomes clogged or ruptures, certain parts of the brain will not receive oxygen and nutrients and may die.

I. What’s Your Blood Type?1. It is safe to mix some blood types, but mixing others causes a person’s RBCs to

clump together – causing death.2. The 4 types are: A, B, AB, or O3. Your blood type refers to the type of chemicals you have on the surface of your

RBCs.- Antigen: Pieces of a pathogen that generate an immune response from

immune-system cells.- Type A blood = has A antigen- Type B blood = has B antigen- Type AB blood = has both A and B antigens- Type O blood = has neither A nor B antigens

4. To Mix or Not to Mix- Different blood types not only have different chemicals on their RBC

surfaces but also may have different chemicals in their plasma (antibodies).

- The body makes antibodies against the antigens that are not on its own RBCs.

∙ People with type B blood make A antibodies, which attack any blood cell with an A antigen on it. Therefore, people with type B blood can’t be given type A or AB blood.

∙ Type O blood (universal donor) – can be given to anyone because there are no A or B antigens on the RBCs surface.

∙ Type AB blood (universal recipient) – can have any blood because they don’t make any antibodies against A or B antigens.

Closed cardiovascular system

The cardiovascular systems of humans are closed, meaning that the blood never leaves the network of blood vessels. In contrast, oxygen and nutrients diffuse across the blood vessel layers and enters interstitial fluid, which carries oxygen and nutrients to the target cells, and carbon dioxide and wastes in the opposite direction. The other component of the circulatory system, the lymphatic system, is not closed. The heart is located in the center of the body between the two lungs. The reason that the heart beat is felt on the left side is because the left ventricle is pumping harder.

II. The Lymphatic System

Your cardiovascular system is not the only circulatory system in your body. As blood flows through your cardiovascular system, fluid leaks out of the capillaries and mixes with the fluid that bathes your cells.

Lymphatic System: A collection of organs that collect extracellular fluid and return it to the blood; the organs in this system include the lymph nodes and the lymphatic vessels.

Your lymphatic system also helps your body fight pathogens.

A. Vessels of the Lymphatic System1. Lymph Capillaries: smallest vessels of the lymphatic system.

- Lymph capillaries absorb fluid and any particles too large to enter the blood capillaries.

- Lymph: The fluid and particles absorbed into lymph capillaries.2. Lymph Vessels: Larger vessels that have valves.

3. Lymph is not pushed by a pump. Instead, the squeezing of skeletal muscles provides the force to move lymph through vessels, and valves help prevent backflow.

4. Lymph drains into large neck veins of the cardiovascular system.

B. Lymphatic Organs1. Lymph Nodes: Small bean shaped organs where particles, such as pathogens or

dead cells, are removed from the lymph.- Lymph nodes contain many WBCs – some engulf pathogens, some

produce chemicals that become attached to pathogens and mark them for destruction.

- When the body becomes infected with bacteria or viruses, the WBCs multiply and the nodes sometimes become swollen and painful.

2. Thymus: Located just above your heart, releases WBCs – then travel to other areas of the lymphatic system.

3. Spleen: Largest lymph organ located in the upper left side of your abdomen that filters blood and releases WBCs.

- When RBCs are squeezed through the spleen’s capillaries, the older and more fragile cells rupture. The RBCs are broken down, and some of their parts are reused.

4. Tonsils: Made up of groups of lymphatic tissue located at the back of your nasal cavity, on the inside of your throat, and at the back of your tongue.

- WBCs in the tonsils defend the body against infection.- Tonsils sometimes become badly infected and must be removed.

III. The Respiratory System

A. Out with the Bad Air; In with the Good1. Your body needs a continuous supply of oxygen in order to obtain energy

from the foods you eat.2. The air you breathe is a mixture of several gases. One of these gases is Oxygen.

When you breathe, your body takes in air and absorbs the oxygen. Then carbon dioxide from your body is added to the air and exhaled.

3. Respiration: The exchange of gases between living cells and their environment; includes breathing and cellular respiration.

- Breathing is not the same as respiration, it is only part of it.- Cellular Respiration: chemical reactions that release energy from food.

B. Breathing: Brought to You by Your Respiratory System1. Respiratory System: A collection of organs whose primary function is to take in

oxygen and expel carbon dioxide; the organs of this system include the lungs, the throat, and the passageways that lead to the lungs.

2. Nose- Primary passageway into and out of the respiratory system. - Air can also enter through the mouth.

3. Pharynx: The upper portion of the throat.- Air, food, and drink travel through the pharynx.- The pharynx branches into 2 tubes:

∙ Esophagus: tube leading to the stomach∙ Larynx: tube leading to the lungs

4. Larynx: The area of the throat that contains and controls the vocal cords.- The ridges you feel on your next when you tilt your head back.- AKA: The Voice Box- Vocal cords are a pair of elastic bands that are stretched across the

opening of the larynx. When air flows between the vocal cords, they vibrate and make sound.

5. Trachea: The air passageway from the larynx to the lungs.- AKA: The Windpipe- The entrance to the trachea is guarded by the larynx

6. Bronchi: The two tubes that connect the lungs with the trachea.- One bronchus goes to each lung and branches into thousands of tiny tubes

called bronchioles.7. Lung: A saclike organ that takes oxygen from the air and delivers it to the blood.

- Alveoli: Tiny sacs that form the bronchiole branches of the lungs.∙ Bronchiole branches to form alveoli

- Capillaries surround each alveolus.8. When people who live at low elevations travel to the mountains, they usually find

that they have difficulty exerting themselves. This is because the concentration of oxygen in the air at high elevations is lower than that at low elevations. Until they become used to the change, people have to take more breaths to supply their bodies with the oxygen they need.

C. How Do You Breathe?1. When you breathe, air is sucked in or forced out of your lungs.2. Diaphragm: The sheet of muscle underneath the lungs of mammals that helps

draw air into the lungs.- Your lungs don’t have muscles for breathing… so you need to use

rib muscles and the diaphragm.- When the diaphragm contracts and moves down, it increases the chest

cavity’s volume – air is sucked in.3. What Happens to the Oxygen?

- When oxygen has been absorbed by red blood cells, it is transported through the body by the cardiovascular system. Oxygen diffuses inside cells, where it is used in cellular respiration.

∙ During cellular respiration, oxygen is used to release energy stored in molecules of carbohydrates, fats, and proteins.

∙ When the molecules are broken apart during the reaction, energy is released along with carbon dioxide and water.

∙ The carbon dioxide and water leave the cell and return to the bloodstream.

∙ The carbon dioxide is carried to the lungs and exhaled.

D. Respiratory Disorders1. Asthma: Irritants cause tissue around the bronchioles to constrict and secrete large

amounts of mucus.2. Bronchitis: Can develop when something irritates the lining of the bronchioles.3. Pneumonia: Bacteria or virus that grows inside the bronchioles and alveoli and

cause them to become inflamed and filled with fluid.4. The Hazards of Smoking

- Smoking is the leading cause of cardiovascular diseases and lung diseases – Emphysema and Lung Cancer.

- Emphysema: Have trouble getting the oxygen they need because their lung tissue erodes away.