Chapter 5 – 6 Homeostasis

1. Chapter 5 – 6 Homeostasis Section 1: Feedback Loops Section 2: Circulatory System Section 3: Respiratory System Section 4: Immune System

2. Section 1: Feedback systems

3. Background • Organisms use feedback systems to maintain internal balance and respond to changing conditions. • Two Types: • Negative Feedback • Positive Feedback

4. Types of Feedback Systems • Used to return the body to normal conditions. • There is a ‘set point’ for many values in the body • Temperature • pH of blood • Blood pressure • Water and salt balance • When the body moves away from the ‘set point’, something will happen to get it back to normal. • Very similar to how a thermostat works in your house

5. Maintaining internal conditions • Examples of Negative feedback loops • Carbon dioxide & Breathing rate • Increased CO2 makes the blood acidic – body responds to return to normal • Exercise • Carbon dioxide levels increase as cells work harder • Respiratory system responds by stimulating diaphragm to contract more rapidly • Breathing rate increases, more CO2is released from body, blood pH returns to normal • Involuntary regulatory system

7. Maintaining internal conditions • Hyperventilation • Occurs when carbon dioxide is lost more rapidly than it is produced • Caused by: • Fever • Aspirin poisoning • Anxiety • Hyperventilation causes blood pH to become too basic * How does breathing into a paper bag help this condition?

9. Positive feedback • Organisms use positive feedback to complete a critical process quickly in order to get back to normal • Keeps moving in a cycle until completed • Blood clotting • Labor • Similar to the “vicious cycle”

10. Blood clotting • Examples • Blood Clotting • Clotting proteins (factor proteins) respond to the scene and pile up to create a clot • These proteins signal more factor proteins, which signal even more • There are many different types of factor proteins for different types of wounds • Process continues until clot is made and bleeding has stopped.

11. BLEEDING Clotting proteins (factor) respond Bleeding Stops Signal more proteins to respond

12. Section 2: Circulatory system

13. Circulatory system Anatomy • Three main parts: • Blood • Heart • Blood vessels

14. Circulatory system Anatomy • Importance of Blood • Red blood cells (Erythrocytes) • Contains hemoglobin - Carries dissolved gasses • Protein found in red blood cells • Oxygen binds to hemoglobin and is transported to all tissues of the body • White blood cells (Leukocytes) • Defend the body against disease • Platelets • Involved in blood clotting • Plasma • Liquid part of the blood • Makes up about 55% of the total blood volume

15. Heart • A muscular organ that pumps blood throughout the body. • Pumps about 5L of blood a minute. • It beats an average of 100,000 times a day • It pumps about 200,000 gallons of blood a day. • It is about the size of your fist. • It has four chambers or “rooms” that hold blood. • Pacemaker • small bundle of cells that controls the rhythm of the heart.

17. Heart Anatomy • The atria (atrium) are chambers that receive blood returning to the heart.

18. Heart Anatomy • Below the atria are the ventricles which are thick walled chambers that pump blood away from the heart.

19. Heart Anatomy • Series of valves prevent blood from going backward http://www.pbs.org/wgbh/nova/body/map-human-heart.html

20. Heart Anatomy • Heart Beat: • Lub sound: Tricuspid and Mitral valve close: • heart contracting, pushing blood • Dub sound: Pulmonary and Aortic valves close: • heart fills with blood—pause takes longer • Heart murmur—one valve doesn’t close completely • http://depts.washington.edu/physdx/heart/demo.html

21. Why do we show half of the heart as blue and the other half as red?

22. Blood Flow • The Heart pumps the oxygen rich blood throughout the body in ARTERIES • Oxygen Poor blood is pumped back to the heart in VEINS *There is one exception to thisrule!

23. Blood Flow • The path of blood: • Heart • Artery • Arterioles • Capillaries • Venules • Veins • Heart

24. Blood Flow • Pulmonary Circuit: Venules ↓ Veins (Superior Vena Cava from above the heart and Inferior Vena Cava from below the heart) ↓ Heart (deoxygenated blood) ↓ LUNGS

25. Blood Flow CO2 Alveoli High in O2 Take in CO2 Lung cell RBC High in CO2 Take in O2 RBC Lung cell Lung cell Lung cell O2 • How do O2 particles move into RBC and CO2 particles into the Alveoli? • diffusion (no energy) • The blood is now oxygenated and moves back to the heart.

26. Blood Flow • Systemic Circuit: Heart (Oxygenated Bloodfrom lungs) ↓ Aorta ↓ Arterioles ↓ Capillaries

27. Cells close to blood pool • What is exchanged at the capillaries? • Oxygen • Carbon dioxide • Nutrients • Hormones

28. Blood Flow • The heart itself cannot get nutrients and oxygen from its own chambers. Why? • It’s too thick for diffusion to work. It must rely on coronary arteries—lie in grooves that spiral around the heart.

29. Heart Disease • Kills one million people a year • Atherosclerosis • Heart disease caused by narrowing of the arteries • Cholesterol plaques build up inside arteries • Causes abnormal blood flow

30. Heart Disease • An obstruction to any of these coronary arteries would require bypass surgery to restore proper blood flow

31. Heart Disease • Blood Pressure - Pressure exerted by the blood on the walls of blood vessels

32. Heart Disease • Heart attack • Occurs when the arteries that deliver oxygen to the heart become blocked. • Usually occurs in the coronary arteries • Heart cells begin to die after 4 – 6 hours without blood

33. Heart attack • Risk Factors • High cholesterol • High blood pressure • Smoking • Family history • Diabetes • Prevention • Early diagnosis of heart disease • Treatment of high blood pressure • Regular medical checkups • Healthy diet • Regular exercise

34. ECG (Electrocardiogram) Machines Measure electrical pulses in the heart.

35. Electrocardiogram

36. Section 3: The respiratory system

37. Anatomy of The respiratory system • Lungs • Made of 5 lobes • Connects with the external environment through the trachea (wind pipe) • Inhale • Oxygen • Exhale • Carbon dioxide Without oxygen, your body can not obtain enough energy from food to survive! Carbon dioxide waste is toxic to cells and must be removed!

38. Anatomy of The respiratory system • Nose • Air is warmed, moistened, and cleaned • Larynx • Contains vocal cords • Trachea (windpipe) • Tube lined with cilia (hair-like structures) that sweep debris out of trachea

39. Anatomy of The respiratory system • Bronchioles • Branches leading to each lobe of the lungs • Alveoli • Smallest lung compartment • Oxygen and carbon dioxide diffuse across thin walls called alveolar membranes

40. Respiratory disease Asthma – when bronchioles of the lungs become constricted because of sensitivity to certain stimuli. - The constriction makes it difficult for oxygen to reach the blood. Emphysema – caused by cigarette smoke - lung tissue loses its elasticity and it becomes more difficult for lungs to expand and take in air Lung cancer – carcinogens from cigarette smoke cause cancerous tumors to grow on lung tissue.

42. Section 4ImmuneSystem

43. What is a virus? • Pathogen-causes disease • Infect cells and use the cell to make more viruses

44. Are viruses alive? • No! • Do not grow • Can not reproduce without a host cell • Not made of cells

45. Nonspecific Defense • Doesn’t have to recognize a specific invader • Skin • Mucus • Saliva • Tears • Sweat • Hair

46. Specific Line of Defense • Using antibodies to target a specific pathogen. • Ex: if you’ve had the chicken pox, you have antibodies ready to go in case you get infected again. They PLAN an ATTACK on a TARGET

48. The BloodMobile

49. Physiology Lab Writing your materials and methods!

50. Write this in your notes: