Chapter 37The Circulatory and the Respiratory

Systems

Vocabulary: Artery Erythrocyte Arteriole Anemia Capillary Leukocyte Venule Leukemia Vein platelet Lymphatic system fibrin Lymph A-B-O system Plasma Rh factor

37-1 The Circulatory System

Describe 4 functions of the circulatory system

Compare and contrast the structure and function of arteries, capillaries, and veins

State the function of the lymphatic system Describe the components of the blood Explain how blood type is determined

objectives

Why do our cells need oxygen? What are advantages of a closed circulatory

system?

Groups of 4 Brainstorm ideas to the above questions.

Opening questions

Introduction: The human body has a closed circulatory

system made of a network of vessels that extend to all tissues of the body in order to provide them with food and oxygen. It also serves to take away the wastes that are produced in these tissues such as the muscles, bones, and nervous tissues

Chapter 37-1

A. The Human circulatory system connects the various muscles and organs of the body with one another. Four types of materials are transported through this system◦ 1. Nutrients and wastes◦ 2. Oxygen and carbon dioxide (gases)◦ 3. Hormones◦ 4. Heat

I. Transport of Materials and Distribution of Heat

a. Food molecules fuel muscle contractions and other cell activities

b. cells receive nutrients from the small intestines

c. wastes are taken from cells to the kidneys where they are filtered out of the blood

1. Nutrients and Wastes

a. Cells need oxygen for cellular respiration

b. carbon dioxide needs to be taken away from the cells. Too much CO2 can be poisonous to the body.

2. Gases – Oxygen and CO2

a. The body maintains a constant temperature by using metabolic energy to make heat.

b. The environment also contributes to the temperature of our body◦ 1. In the cold blood vessels constrict to try to

conserve body heat◦ 2. In the heat blood vessels dilate and let heat

escape the body

3. Heat

a. The body coordinates the activities of many organs with hormones (chemical messengers of the endocrine system)

b. The circulatory system carries the hormones to the target cells in the body.

4. Hormones

A. There are four major components of the human circulatory system◦ 1. Blood vessels – network of tubes that move

the blood throughout the body◦ 2. Lymphatic vessels – recover fluid that leaks out

of the blood vessels◦ 3. Blood – mixture of specialized cells and fluid◦ 4. Heart – Muscular pump that moves the blood

through the vessels

B. Components of the Circulatory System

B. Pathway of circulation : Arteries -> Arterioles-> Capillaries-> venules -> veins->Heart

1. Arteries – tubes that carry blood away from the heart. Arterial walls are tough, thick and expandable to accommodate for pressure of the blood forced out of the heart. It has 3 layers of tissue:◦ a. endothelium – inner thin layer made of

epithelial cells◦ b. smooth muscle layer – middle stretchy layer◦ c. Connective tissue – protective outer layer◦ The biggest and thickest of the arteries is the

Aorta

a. thin walls – simple tubes one cell thick for the exchange of gases

b. Narrow in diameter – only slightly wider than one red blood cell so oxygen can diffuse out of the red blood cell into the body cell

5 % of our blood is in our capillaries. Capillaries put end to end would be several thousand miles in length – able to stretch across the U.S.

2. Capillaries

a. Return blood to the heart. c. Contain valves to keep blood flowing in

the same direction – working against gravity and not having the same pressure to move the blood as the arteries have.

d. Have the same layers as arteries but they are not as thick or tough.

c. The largest vein in the body is the VENA CAVA leading into the heart.

3. Veins

a. Fluids that do not return to capillaries collect in spaces around the body’s cells – sometimes causing swollen feet or hands.

b. Lymph – fluid of the lymphatic system c. Lympahtic vessels – collect the fluid surrounding cells and

carries it to ducts that drain into veins in the neck. These vessels contain valves similar to the ones in veins. The Lymph is pushed through the vessels by contracting muscles in the arms and legs.

d. Lymph nodes – filter foreign substances from the lymph before it returns to the circulatory system. An infection in the body may cause the nodes to swell. They are concentrated in the armpits, neck, and groin areas

e. Thymus, tonsils, spleen, appendix, and bone marrow all contain lymph tissue for fighting infections

4. Lymphatic Vessels

A. Plasma – liquid portion of the blood◦ 1. 90% water◦ 2. Metabolic Wastes – glucose, food molecules,

vitamins, hormones, and nitrogen wastes◦ 3. Salts and Ions – sodium, chloride, bicarbonates,

and traces of calcium, magnesium, metallic ions (copper, potassium, and zinc)

◦ 4. Proteins – keep plasma from losing water to the body cells.

C. Blood Components

B. Blood Cells◦ 1. Red blood cells – erythrocytes

Round flat disks that are collapsed in the center Center carries the protein hemoglobin – binds to

oxygen. Does not have a nucleus Can NOT repair itself or make proteins Life span of about 120 days Produced in the bones red bone marrow by stem

cells.

ANEMIA – a decrease of hemoglobin in the blood. Anemia reduces the amount of oxygen that

RBCs can transport resulting in a lack of energy, shortness of breath on minor exertions, listlessness, pale skin and a general feeling of fatigue. There are a number of types of anemia: Iron-Deficiency Anemia – Most common –

vitamin B12 deficiency, nutritional deficiencies, excessive iron loss

2. White Blood Cells – Leukocytes◦a. Larger in size then RBCs◦b. smaller amount - 1/1000 RBCs◦c. primary cells of the immune system

i. Lymphocytes – produce antibodiesii. Macrophages – Wonder out of cells to fight infections.

d. Cancer of the White Blood Cells is called leukemia

3. Platelets – Thrombocytes◦a. cell fragments that lack a nucleus

◦b. play a role in blood clotting (coagulation)

◦c. Lack of the clotting protein results in a genetic disorder called hemophilia

d. Hemostasis is the stoppage of blood flow leading to coagulation. Hemostasis has 3 stages.◦ 1. Platelet plug forms – platelets become sticky and

stick to the damaged site. As the platelets pile up the small mass is called a platelet plug.

◦ 2. Vascular spasms and vessel dialation - serotonin◦ 3. Coagulation – Prothrombin is converted to

thrombin which joins fibrinogen to make fibrin which acts as a net to capture RBCs and form the clot.

◦ Normally, blood clots within 3 to 6 minutes.

Thrombus – a clot in an unbroken blood vessel. Usually occurs in the legs. If large enough, it may prevent blood flow to cells beyond the blockage. If a thrombus forms in the vessels of the heart it is called a coronary thrombosis which may cause a fatal heart attack.

Embolus – a moving thrombus. Usually not a problem unless it lodges in a narrow blood vessel. This could lead to a stroke.

Undesirable clotting

A. We use what is called the A-B-O system for typing blood.

B. We determine blood types by the type of antigen found on the surface of the RBCs. ◦ A Antigen = A blood◦ B antigen = B blood◦ Both A, B antigens = AB blood◦ No Antigens = O blood

D. Blood Type

C. Antibodies in our blood plasma act against foreign antigens and may cause clumping (agglutinate) of the blood which could be fatal.◦ A type have B antibodies◦ B type have A antibodies◦ AB blood has no antibodies◦ O blood has both A & B antibodies

◦ Before a blood transfusion can be performed it is important to know the blood type of the donor and the recipient. Many other makers are considered before blood is given to another person.

D. Rh factor - named for the Rhesus monkey where it was first discovered. ◦ Another type of antigen found on the surface of the blood.◦ Those that have the antigen are Rh+◦ Those that do not have the antigen are Rh-◦ Most Americans are Rh+◦ This plays a role in pregnancy. If an Rh- mother carries an

Rh + baby the first pregnancy will be normal, but the mother will produce antibodies to the Rh- blood, so the second pregnancy the antibodies from the mother’s blood will attack the child’s RBCs. This is called erythroblastosis fetalis. Today this is rare because the mother can be given a drug called RhoGAM immediately after her first birth.

Rh factor

I. The human heart is a double pump made of 4 chambers. One side powers an oxygen acquiring phase, while the other side powers an oxygen delivery phase.◦ A. The Heart pumps blood in two separate

loops. 1. Pulmonary circulation – Heart to lungs and

back. a. right side of the heart b. Deoxygenated blood receives oxygen in

the lungs and releases it’s carbon dioxide in the lungs.

37-2 The Heart

◦ 2. Systemic Circulation – delivers blood to the body tissues and returns it to the heart. a. Left side of the heart b. Oxygenated blood is pushed out to

the bodies tissues to deliver oxygen and pick up wastes including carbon dioxide to deliver back to the heart.

1. Blood enters the heart from the body through the vena cava. The upper half through the superior vena cava and the lower half through the inferior vena cava.

2. The right atrium receives the blood from the vena cava.

3. It then flows through the tricuspid valve to the right ventricle.

4. The right ventricle then pushes the blood through the pulmonary valve into the pulmonary artery.

B. Path of blood through the heart

5. The pulmonary artery takes the blood to the right and left lungs.

6. It then returns to the heart through the pulmonary veins which empty it into the left atrium.

7. It then flows through the bicuspid (mitral) valve to the left ventricle.

8. The left ventricle then pumps the blood through the aortic valve to the aorta where it is delivered out to the body.

1. Atria are the upper receiving chambers. 2. Ventricles are the more muscular lower

pumping chambers. 3. The atria contract simultaneously to

pump blood to the ventricles. Both ventricles then contract together to push blood out of the heart.

C. The chambers

1. The atrioventricular valves are found between the atria and the ventricles.◦a. Tricuspid – between the rt. Atrium and rt. Ventricle. 3 flaps.

◦b. Bicuspid (mitral) valve – between the left atrium and left ventricle. 2 flaps.

D. The valves

2. Semilunar valves – valves between the ventricles and the vessels◦a. Pulmonary valve – valve between the right ventricle and the pulmonary artery.

◦b. Aortic valve – valve between the left ventricle and the aorta.

◦Cords called chordae tendineae connect the flaps of the valves to muscle projections called papillary muscles.

1. The heart is enclosed in a loose fitting serous membrane known as the pericardial sac. The sac is made of two layers.◦a. Fibrous pericardium – outer layer,

protects and anchors the heart◦b. Serous pericardium – thin inner layer

next to the heart – also called the epicardium.

E. The layers of the heart

2. Heart wall layers◦ a. Epicardium (serous pericardium) – thin outer

transparent layer. Inflammation of this tissue due to friction is called pericarditis.

◦ b. Myocardium – thick muscular layer of the heart that makes up the bulk of the heart

◦ c. Endocardium – thin inner layer lines the myocardium and covers the valves of the heart and the chordae tendineae of the valves.

Contractions of the heart are controlled by the autonomic nervous system. The heart also has its own regulating system called the conduction system that generates and distributes electrical impulses over the heart to stimulate cardiac muscle fibers to contract.

F. Contractions of the Heart

1. The system begins at the sinoatrial node known as the SA node or pacemaker. The SA node initiates each cardiac cycle and sets the pace for the heart rate. ◦a. The SA node is located in the upper right atrium

◦b. It stimulates both atria to contract at the same time.

Sinoatrial node

2. The contraction of the atria then stimulates the atrioventricular node (AV node) which is located in the lower portion of the right atrium.

3. From the AV node a tract of conducting fibers called the bundle of His runs between both ventricles separating into left and right branches. The bundle of His stimulates the medial portion of the ventricles.

Contraction of the Ventricles

4. The actual contraction of the ventricles is stimulated by the Purkinje’s fibers that emerge from the bundle branches and pass into the myocardium of the ventricles.

On the average heart contractions are initiated at a rate of about 72 beats per minute. During sleep this rate decreases. During exercise this rate increases.

A. High Blood Pressure or Hypertension◦ 1. High blood pressure is where the pressure in

the vessels has been increased. Sometimes called the “silent killer” because there are few symptoms helping to detect it. a. It can be measured by a sphygmomanometer b. Diastolic pressure – The bottom number measures

pressure while the atria are filling. c. Systolic pressure – The top number measures

pressure when the ventricles contract. d. Normal blood pressure 120/80

B. Cardiovascular disorders

B. Heart attack – lack of blood or oxygen to an area of the heart muscle leading to the death of the cardiac muscle cells. It is the leading cause of death in the United States.

1. Can be cause by blocked coronary artery due to deposits of fatty material on the walls of the artery called atherosclerosis.

2. Atherosclerosis can lead to arteriosclerosis which is hardening of the arteries. Calcium deposits in the fatty buildup harden the artery itself where it is no longer able to stretch causing a build up of pressure and the heart to work harder.

2. EKG or ECG (electrocardiogram) – used to measure the electrical impulses produced by the heart as it contracts. Electrical current passes through the body and can be detected by sensors placed on the skin. This currents are recorded in an electrocardiogram.◦ a. P Wave – atria contract◦ b. QRS wave – ventricles contract◦ c. T wave – ventricles relax

Respiration is the overall exchange of gases between the atmosphere and lungs or between blood and cells.

Breathing (pulmonary ventilation) is a mechanical process that depends on pressure and volume changes occurring in the thoracic cavity.

Inspiration is when air is flowing into the lungs.

Expiration is when air is leaving the lungs

37-3 The Respiratory system

A. Respiratory passages – conductiong zone◦1. The nose- entry way of the respiratory

system a. Nostrils (external nares) – the

opening to the nose. b. Nasal cavity – interior space of the

nose, divided into two by the nasal septum.

c. Functions – warm air, filter air, smell, moisten air

I. Parts of the Respiratory system

2. The Pharynx – muscular passageway called the throat. Is part of the respiratory system and digestive system.◦a. Nasopharynx – upper part – contain

adenoids (pharyngeal tonsils)◦b. Oropharynx – mouth area – contain

palatine tonsils and lingual tonsils.◦c. Laryngopharynx - entry way to the

larynx

3. Larynx or voice box◦ a. Plays a role in speech◦ b. Routes food and air to the proper channels◦ c. Is made of 8 hyaline cartilages with a spoon-shaped

flap of elastic cartilage called the epiglottis.◦ d. The largest of the hyaline cartilages is called the

thyroid cartilage or adam’s apple.◦ e. The epiglottis closes as we swallow food or drink. If

either of these enters the larynx a cough reflex is triggered to expel the substance.

◦ f. Vocal folds or true vocal cords are mucous membranes that vibrate with expelled air. This allows us to speak and gives our voices pitch.

4. Trachea – or windpipe is made of c –shaped rings of hyaline cartilage which allow the esophagus to expand while swallowing and also are rigid enough to hold the passage ways open during pressure changes of breathing.

5. Bronchi – or Primary Bronchi are found at the end of the trachea and split into a right and left bronchi entering into the right and left lungs.◦ a. The bronchi split into many smaller branches

within the lungs and are direct routes to the microscopic air sacs.

◦ b. Secondary bronchi, tertiary bronchi, terminal bronchiole, Respiratory bronchioles (largest to smallest) – make up the bronchial tree.

6. Lungs – Right lung has 3 lobes while the left lung has 2 lobes. They surround the heart.◦ a. Apex is the narrow upper part of the lungs◦ b. Base is the wider bottom part of the lungs◦ c. The words pulmonary and pleura have to do with

the lungs. ◦ d. Parietal pleura – membranes of the thoracic

cavity, pleural fluid – serous fluid to reduce friction, visceral pleura – membrane on the lungs, pleural cavity (space) is the area between the two membranes filled with pleural fluid.

7. Alveoli – Microscopic sacs on the end of the bronchioles. ◦a. The respiratory zone – includes respiratory bronchioles, alveolar ducts and alveolar sacs is the only site of gas exchange.

◦b. The alveoli are covered with capillaries so the blood and air can diffuse from one to the other.

A. Pressure changes – breathing is the result of pressure changes that occur inside the pleural cavity (cavity containing the lungs) and the lungs.◦ 1. Air moves into the lungs when the air pressure

outside is higher than inside the lungs.◦ 2. Air moves out of the lungs when there is more

pressure within the lungs than the outside pressure.

II. Inhalation and Exhalation

B. Inhalation – ◦1. The diaphragm contracts and moves

downward◦2. The ribcage moves upward and

outward.◦3. This enlarges the volume of the chest

cavity lowering the pressure within the chest area.

◦4. Air rushes from atmosphere(high pressure) into the lungs (low pressure)

C. Exhalation –◦ 1. The diaphragm and ribs relax and return to

normal position◦ 2. This decreases the size of the chest area

increasing the pressure and pushing the air out.◦ 3. Exhalation is a passive process unlike

inhalation which is an active process.

1. Receptor s in the brain and circulatory system continually monitor the levels of oxygen and carbon dioxide in the blood

2. Carbon dioxide levels 3. Stress 4. pain 5. fear

D. Factors influencing breathing rate

1. Breathing is the first step to getting oxygen to the millions of cells in our bodies. As oxygen passes into the plasma of the bloodstream, it is picked up b red blood cells that contain an oxygen-carrying protein called hemoglobin.

2. Hemoglobin contains iron molecules which give blood their red color. The iron reversibly bind to oxygen, which means that at the appropriate time, the oxygen can be released elsewhere in the body and used by cells that need it.

E. Transport of O2 and CO2

3. Path of oxygen and carbon dioxide through the body:◦ a. Oxygen form the outside reaches the lungs◦ b. O2 diffuses from alveoli to capillaries – hemoglobin carries a

full load of O2◦ c. O2 rich blood goes to the heart where it is pumped to the

body◦ d. O2 diffuses into cells for cellular respiration – these cells

have low O2 levels causing the hemoglobin to release its O2.◦ e. CO2 produced by cellular respiration in these tissues makes

the blood more acidic causing the hemoglobin to change shape. This causes the release of oxygen and the CO2 to diffuse into the blood.

◦ f. Most of the CO2 travels to the heart as bicarbonate ions◦ g. The heart pumps the blood to the lungs where the CO2 is

released and expelled

4. Carbon dioxide is carried in the blood in three forms◦a. 7 percent is dissolved in the blood plasma

◦b. 23 percent is attached to hemoglobin molecules

◦c. 70 percent is carried to the blood as bicarbonate ions.

The effect of carbon dioxide on oxygen unloading (release from hemoglobin) is called the BOHR EFFECT .

The Bohr effect is of great importance because it means that blood unloads oxygen more readily within those tissues that undergo a high rate of cellular respiration.

These are the very tissues that need oxygen the most

The Bohr effect

1. Asthma – Disease in which the bronchioles of the lungs constrict (narrow), because of their sensitivity to certain stimuli in the air. In severe allergic asthma attacks, the alveoli may swell enough to rupture. Stressful situations and strenuous exercise may trigger an asthma attack. Left untreated it can be deadly. Prescribed inhalant medicines may help to counteract an asthma attack. People of all ages have asthma.

F. Respiratory Diseases Limit Lung Function

2. Emphysema – a chronic pulmonary disease of the lungs. The alveoli lose their elasticity, making it difficult to release air during exhalation. People with emphysema suffer from constant fatigue and breathlessness. Severely affected individuals must use tanks of oxygen in order to live. Emphysema is often the result of cigarette smoking as is lung cancer. Both claim millions of lives annually.

3. Lung cancer – One of the leading causes of death in the world today. It is a disease characterized by abnormal cell growth in the lungs. Once cancer is detected, the affected lung is usually removed surgically. Even with these drastic measures, fewer than 10 percent of lung cancer victims live more than 5 years after diagnosis.

Normal lung vs. smokers lung

Lung Tissue slides

Normal

Cancer

Emphysema