Circulatory and Respiratory Systems in Human Biology

1. Chapter 30Circulatory & Respiratory Systems Mr. Taylor Biology Rainier Jr/Sr High School

2. Circulatory System • Blood vessels and a muscular pump (heart) • Transports • Nutrients from digested food • Oxygen (O2) to all cells • Metabolic wastes (CO2, urea, creatinine, etc.) to excretory organs • Hormones • Distributes heat (both conserving and radiating)

3. Blood Vessels (Vascular organs) • Arteries carry blood away from the heart. • Endothelium; inner lining • Elastic fibers to absorb pumping forces • Capillaries connect arteries to veins • Exchange of gases and nutrients • Veins carry blood back toward heart • Low pressure • Large diameter minimizes resistance to flow.

4. Lymph System • This system collects the fluid that leaks out into the spaces between the cells and returns it to blood vessels. • This system is also involved in immune functions • Foreign or defective cells (like bacteria, viruses, and cancer cells) are removed in lymph nodes.

5. Plasma and Cells: the two major components of blood • Blood Plasma is the liquid component of blood • Accounts for 60% of blood volume. • Water makes 90% of the plasma • Dissolved glucose, hormones, and urea (a waste product of protein metabolism). • Ions and salts such as Sodium, Potassium, Chloride, and Bicarbonate. • Proteins • Help keep water in the blood vessels • Helps transport some substances • Aids in blood clotting • Antibodies eliminate foreign or defective cells.

6. Plasma and Cells: the two major components of blood • Cells make up about 40% of the blood volume. • Red Blood Cells (erythrocytes) carry Oxygen on hemoglobin (contain iron) molecules. • Anemia: too few Red Blood Cells • White Blood Cells: also called leukocytes, aid in immune functions. • Lymphocytes, Monocytes, Neutrophils, Basophils, and Eosinophils • Platelets are fragments of megakaryocytes that are critical in blood clotting.

7. Circulatory System • The human circulatory system is a two-loop system • Heart to lungs to heart (Pulmonary circulation) • Heart to body to heart (Systemic circulation) • This system allows for maximum Oxygen delivery to the cells.

8. Heart • The human heart is a 4-chambered heart • Atria/atrium: receive blood into the heart • Ventricles: pump blood out of the heart • Valves are present to allow only one-way flow

9. Heart • Blood flow • From body via superior and inferior vena cava into the right atrium • Right atrium to Right ventricle • Right ventricle to lungs via pulmonary arteries • From lungs to left atrium via pulmonary veins • From left atrium to left ventricle • From left ventricle to body via aorta

10. Electrical Conduction system • The cardiac muscle is triggered to contract rhythmically • An impulse is generated in the sino-atrial node (SA node) • This impulse ripples over the two atria • The impulse then travels across the ventricles pumping the blood out of the heart.

11. Measurements of Cardiac function • Blood Pressure: • Systole is when the ventricles pump • Diastole is when the ventricles fill • Pressure is usually reported as systolic/diastolic • “normal” is about 120/80 • EKG/ECG monitors and measures the electrical activity of the heart. • Pulse is counted in several areas of the body • “normal” is about 72/minute • Ultrasound is used to take a moving image of the heart and blood as the heart beats.

12. Blood Types • There are many factors in blood typing, but there are only 2 that we are concerned with: • ABO Blood Types: Surface proteins A or B (co-dominant) may be present resulting in Blood Type A, or B, or AB. If neither is present, the Blood Type is O. • Rh factor: The protein is either present (+) or not (-). • This is the factor that can cause problems between mothers and their unborn children.

13. Respiratory System • The respiratory system is responsible for the exchange of gases between the body and the atmosphere. • The respiratory system consists of the lungs plus all the airways and alveoli • Oral cavity/nasal cavity  pharynx  larynx  trachea  bronchi  bronchioles  alveoli • Alveoli are sacs of epithelium covered with capillaries and are the site of all gas exchanges. • The millions of alveoli give a surface area > 40 times greater than your body surface area.

14. Respiratory Epithelium • Most airways are lined by a ciliated epithelium and have cells that produce a lot of mucus. • The mucus traps bacteria and viruses and airborne particles (smoke, dust, etc.) that would cause trouble in the alveoli. • The cilia move this mucus and trapped junk to the larynx where it is swallowed. • The bacteria and viruses (and some of the particles) are digested/destroyed in the stomach.

15. Negative Pressure Breathing • The lungs are inside a closed thoracic cavity bounded by the ribs and the diaphragm. • Lifting the ribs and contracting the diaphragm makes the cavity larger and reducing the pressure inside it (creates a partial vacuum). • Air is “sucked” into the lungs to equalize this vacuum. • The respiratory rate is controlled mostly by the concentration of CO2, but O2 concentration, pain, and emotional factors also influence the rate.

16. Transport of Oxygen • Oxygen (O2) is carried by molecules of hemoglobin in Red Blood Cells. It moves by simple diffusion from areas of high concentration to areas of low concentration. • In lungs, O2 concentration is high in the alveoli and low in the blood … oxygen diffuses into the blood. • In the tissues O2 concentration is high in the blood and low in the cells … oxygen diffuses into the cells.

17. Transport of Carbon Dioxide (CO2) • Carbon dioxide (CO2) is carried: • Dissolved in the plasma as CO2, about 5% • On hemoglobin molecules on RBC’s, about 30% • As part of the bicarbonate ion (HCO3-) which acts as a buffer to maintain pH balance, about 65%

18. Respiratory Diseases • Pneumonia: Inflammation and disease of the lung tissue. May be due to viruses, bacteria, or allergy. • Chronic Obstructive Pulmonary Diseases (COPD) • Asthma: airways constrict and reduce airway diameter. Usually and allergic/immune system problem • Emphysema: loss of elastic fibers in lungs makes it hard to get air out of lungs so the person must “squeeze” his/her chest to get the air out. Smoking is the most common reason for this disease. • Lung Cancer: abnormal cell reproduction. Very deadly even with treatment. Smoking is the most common cause of this disease.