1. Lecture for Chapter 32
Circulation

2. Chapter 32 Outline
32.1 What Are the Major Features and Functions of Circulatory Systems?
32.2 How Does the Vertebrate Heart Work?
32.3 What Is Blood?
32.4 What Are the Types and Functions of Blood Vessels?
32.5 How Does the Lymphatic System Work with the Circulatory System?

3. Section 32.1 Outline
32.1 What Are the Major Features and Functions of Circulatory Systems?
Animals Have Two Types of Circulatory Systems
The Vertebrate Circulatory System Has Many Diverse Functions
Three major parts
Blood: a specialized bodily fluid that delivers necessary substances to the body's cells (in animals) – such as nutrients and oxygen – and transports waste products away from those same cells
Blood vessels: the part of the circulatory system that transports blood throughout the body (arteries, capillaries, veins)
Heart: a muscular organ found in all animals with a circulatory system (including all vertebrates), that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions

4. Two Types of Systems
Open circulatory system: space within the body cavity (hemocoel혈강)
Found in arthropods절지동물 and most mollusks연체동물

5. Two Types of Systems
Closed circulatory system: blood confined within continuous vascular network with a pumping heart
Found in some invertebrates and all vertebrates
Fast blood flow
Efficient transportation of nutrients and wastes
Higher blood pressure

6. Diverse Functions of the Vertebrate’s Circulation System
1. Transport of O2 and CO2
2. Distribution of nutrients
3. Transport of waste
4. Distribution of hormones
5. Regulation of body temperature
6. Prevent blood loss
6. Protect against disease

7. Section 32.2 Outline 32.2 How Does the Vertebrate Heart Work?
Increasingly Complex and Efficient Hearts Have Arisen During Vertebrate Evolution
The Vertebrate Heart Consists of Muscular Chambers

8. Evolution of the Vertebrate Heart
Vertebrate hearts have muscular chambers called atria and ventricles
Atria (심방) collect blood from body
Contract and deposit blood in ventricles
Ventricles (심실) contract and discharge blood to body

9. Evolution of the Vertebrate Heart
Two chambered hearts
Earliest vertebrate hearts with one atrium and one ventricle
Example: fish hearts
+ O2, - CO2
- O2, + CO2

10. Evolution of the Vertebrate Heart
Three chambered hearts
Have two atria and one ventricle
Examples: amphibian and most reptile hearts
+ O2, - CO2
- O2, + CO2

11. Evolution of the Vertebrate Heart
Four chambered hearts
Most advanced
Have two atria and two ventricles
Separation of O2-rich and O2-poor blood maximizes O2 levels in blood
Examples: bird and mammal hearts
+ O2, - CO2
- O2, + CO2

12. Human Heart Function
Two types of blood vessels connect to heart chambers:
Veins: carry blood to atria
Arteries: carry blood away from ventricles
하대정맥
상대정맥
대동맥
하행 대동맥

13. Human Heart Function Made of two separate pumps
하대정맥
상대정맥
대동맥
하행 대동맥
Made of two separate pumps
Right pump: made of right atrium and right ventricle
Left pump: made of left atrium and left ventricle

14. Human Heart Function Right pump
하대정맥
상대정맥
대동맥
하행 대동맥
Right pump
Right atrium receives O2-poor blood from body by superior and inferior vena cavae
Right ventricle ejects O2-poor blood into pulmonary arteries to be oxygenated by lungs

15. Human Heart Function Left pump
하대정맥
상대정맥
대동맥
하행 대동맥
Left pump
Left atrium receives O2-rich blood from lungs by pulmonary veins
Left ventricle ejects O2-rich blood into aorta to be distributed to body tissues

16. Human Heart Function Pumps separated by ventricular septum 심실격벽 대동맥
하대정맥
상대정맥
대동맥
하행 대동맥
Pumps separated by ventricular septum 심실격벽

17. Cardiac Muscle The heart is composed of cardiac muscle tissue
Cardiac muscle cells are
Small, branched, and striated
Linked to one another via intercalated discs containing gap junctions
Gap junctions allow the electrical signals that trigger contractions to spread directly and rapidly from one muscle cell to the next
This results in the coordinated, synchronous contraction of heart muscle

18. The Cardiac Cycle The heart beats in a coordinated fashion:
Both atria contract and pump blood into ventricles
Both ventricles contract and pump blood into arteries
All chambers relax briefly before the cycle repeats
This cardiac cycle lasts less than 1 second

19. Blood Pressure
Heart chamber contractions generate blood pressure that drives blood flow:
Systolic pressure(수축기압): blood pressure during ventricular contraction
Diastolic pressure(확장기압): blood pressure during ventricular relaxation
Blood pressure can be measured using a blood pressure cuff

20. High Blood Pressure
High blood pressure (hypertension) is caused by the constriction of arterioles
Causes resistance to blood flow and strain on the heart
Borderline reading for high blood pressure is 140/90
Hypertension interacting with hardened arteries can lead to blood clot formation
Blood clots can block arteries, leading to
Heart attack
Stroke

21. Heart Valves(판막)
하대정맥
상대정맥
대동맥
하행 대동맥
Heart valves insure one-way flow of blood through heart
Insures that O2-poor blood is sent to lungs and O2-rich blood is sent to body tissues
Atrioventricular valves (방실판막): allow blood to flow from atria to ventricles, prevent back flow
Semilunar valves (반월판): allow blood to flow from ventricles to arteries, prevent back flow

22. Coordination of Contractions
Pacemaker (박동원) cells coordinate cardiac cycle
Heart cells that regularly produce spontaneous electrical impulses
Impulses spread throughout heart muscle cells and stimulate them to contract
Sinoatrial (SA) node is the primary pacemaker
In upper wall of right atrium
Generates impulses that spread throughout cardiac muscle cells of atria
Atrial cells contract in unison and finish emptying blood

23. Coordination of Contractions
Atrioventricular (AV) node: second pacemaker cell cluster
In floor of right atrium
Stimulated by SA node impulse
After a 0.1 second delay, sends impulse to ventricles by excitable fibers
Ventricles contract when stimulated

24. Control of Heart Rate
SA node maintains heart rate of 100 beats per minute (bpm)
Nervous system modifies heart rate:
At rest, parasympathetic nervous system slows heart rate to ~70 bpm
During exercise and stress, sympathetic nervous system increases heart rate
Endocrine system modifies heart rate
Under stress, the hormone epinephrine (adrenalin) is released
Stimulates SA node and increases heart rate

25. Section 32.3 Outline 32.3 What Is Blood?
Plasma Is Primarily Water in Which Proteins, Salts, Nutrients, and Wastes Are Dissolved
Red Blood Cells Carry Oxygen from the Lungs to the Tissues
White Blood Cells Help Defend the Body Against Disease
Platelets Are Cell Fragments That Aid in Blood Clotting

26. Two Major Blood Components
Plasma: fluid portion of blood
55-60% of blood volume
Cellular components: made of red blood cells, white blood cells, and platelets
40-45% of blood volume

27. Plasma ~90% water Other components Hormones Nutrients Gases Salts
Wastes
Proteins

28. Plasma Proteins Three major types
Albumins: maintain osmotic pressure of blood
Globulins: transport nutrients and act in immunity
Fibrinogen: involved with blood clotting

29. Red Blood Cells Also called erythrocytes
Make up 99% of all blood cells
Carry oxygen from lungs to tissues
Human erythrocytes have a biconcave disk shape
Red color caused by pigment hemoglobin
Composed of four polypeptide chains and four iron-containing heme groups
Each heme group binds to O2 in lung and turns hemoglobin cherry red
Hemoglobin releases O2 and picks up some CO2 at tissues

30. Red Blood Cell Life Span
Formed in red bone marrow
During formation, nucleus is removed
Red blood cells live ~ 4 months
2 million red blood cells die per second and are replaced by bone marrow
Removed by liver and spleen
Iron recycled and used to form more hemoglobin
When blood O2 levels are low, erythropoietin is released by kidneys
Stimulates additional red blood cell formation by bone marrow
Controlled by negative feedback

31. White Blood Cells Also called leukocytes
Make up < 1% of all blood cells
Most protect body against disease
Example: lymphocytes
Can produce antibodies used in immunity
Example: macrophages
Mobile and amoeba-like
Engulf foreign particles and bacteria

32. Platelets Fragments of megakaryocytes formed in the red bone marrow
Pieces pinched off and enter circulation
Involved in clotting
Last days

33. Blood Clotting Keeps animals from bleeding to death Blood clot
Formed from sticky fibrin protein threads, platelets, and other cells forming patch over wound site

34. Blood Clot Formation
Results from interaction among circulating plasma proteins, particularly thrombin and fibrinogen
Aggregated platelets in clot constrict after ~ 30 minutes
Tightens fibrin web and forces liquid out of clot
Results in denser, tougher clot
On skin surface, called a scab

35. Section 32.4 Outline
32.4 What Are the Types and Functions of Blood Vessels?
Arteries and Arterioles Are Thick-Walled Vessels That Carry Blood Away from the Heart
Capillaries Are Microscopic Vessels That Allow the Blood and Body Cells to Exchange Nutrients and Wastes
Veins and Venules Carry Blood Back to the Heart
Arterioles Control the Distribution of Blood Flow

36. Pattern of Blood Flow Blood flows through blood vessels From heart 
Arteries  arterioles  capillaries  venules  veins  back to heart

37. Arteries Thick walled vessels
Contain smooth muscle and elastic tissue to withstand high pressure
Arterioles
Branch off of arteries
Smaller in diameter
Help control distribution of blood flow

38. Capillaries Tiniest vessels—thin, single-cell thick for easy diffusion
Allow exchange of materials between blood, interstitial fluids, and body cells
Nutrients
Gases
Hormones
Blood pressure drives fluid leakage out of capillaries and into spaces surrounding tissue cells (i.e., interstitial fluid)

39. Venules Veins Capillaries merge to form larger venules
Venules merge to form veins
Veins
Contain smooth muscle and elastic tissue
- Wider, thinner walled than arteries
- Contain one-way valves that allow blood to flow only to heart
- Skeletal muscle contractions compress veins and drive blood movement towards heart

40. Distribution of Blood Flow
Muscular arteriole walls contract and relax to redirect blood flow and regulate blood pressure
Controlled by nerves, hormones, and nearby chemicals
Capillary blood flow controlled by precapillary sphincter muscles
At junction of arterioles and capillaries
- Open and close due to changes in local conditions
- Example: open when cellular wastes accumulate to encourage blood flow

41. Section 32.5 Outline
32.5 How Does the Lymphatic System Work with the Circulatory System?
Lymphatic Vessels Resemble the Veins and Capillaries of the Circulatory System
The Lymphatic System Returns Fluids to the Blood
The Lymphatic System Transports Fats from the Small Intestine to the Blood
The Lymphatic System Helps Defend the Body Against Disease

42. The Lymphatic System Functions
Includes lymphatic vessels, lymphatic capillaries, lymph nodes, thymus(흉선), and spleen (비장)
Functions
(1) Returns excess interstitial fluid to bloodstream
(2) Transports fats from small intestine to bloodstream
(3) Contributes to immunity

43. Lymphatic Capillaries
“Dead-end” lymphatic capillaries collect excess interstitial fluid from tissues
Lymph: fluid in lymphatic system
Lymphatic capillary cells overlap
Act as one-way valves
Allow fluid and particles to drain into lymphatic capillaries
Merge to form lymphatic vessels

44. Lymphatic Vessels
Similar in structure to veins, including one-way valves
Muscle contractions drive lymph flow

45. Return of Fluid to the Blood
3 to 4 liters of excess interstitial fluid are generated per day
Collected by lymphatic system and deposited into general circulation where thoracic duct joins with vena cava

46. Return of Fluid to the Blood
Elephantiasis: a disease caused when parasitic roundworms colonizes lymphatic vessels
Prevent draining of lymph and causes extreme swelling (edema)

47. Transport of Dietary Fats
Small intestine has many lymphatic capillaries
Lymph is composed of ~1% of fat-transporting particles
Too large to diffuse into blood capillaries
Travel in lymph until introduced into general circulation

48. Defense Against Disease
Tonsils (편도): patches of connective tissue containing many lymphocytes
Destroy bacteria and viruses
Lymph nodes: kidney-shaped structures found connecting lymph vessels
Contain many macrophages and lymphocytes
Destroy foreign particles in lymph
Thymus: found above heart
Important site of lymphocyte development
Spleen: found in abdominal cavity
Functionally similar to a lymph node, but filters blood instead of lymph
Destroys old red blood cells