1. 2018 Biology2
Chapter 23. Circulation

3. Most animals have a circulatory system
The major functions of the circulatory system
Transportation of O2 and nutrients to the tissue
Transportation of metabolic wastes to waste disposal organs (e.g., lung and kidney)
Hormone distribution
Homeostasis
Body defense
Temperature regulation

4. The circulatory system associates intimately with all body tissues
Capillaries are microscopic blood vessels
They form an intricate network among the tissue cells
Red blood cell
Capillary

5. Capillary Interstitial fluid Cell
Tissue cell
Diffusion of molecules

6. 23.1 Circulatory systems facilitate exchange with all body tissues
MECHANISMS OF INTERNAL TRANSPORT
23.1 Circulatory systems facilitate exchange with all body tissues
In cnidarians and flatworms, the gastrovascular cavity functions in both
digestion
internal transport
Mouth
Circular canal
Figure 23.2A

7. Most animals have a separate circulatory system, either open or closed
Open circulatory systems
A heart pumps blood through open-ended vessels into spaces between cells (the blood is not confined to the vessels)
No distinction between blood and interstitial fluid

8. Closed circulatory systems
The blood is confined to the vessels
Three kinds of vessels
Artery: heart  tissue
Vein: tissue  heart
Capillary: tissue에서 artery와 vein사이의 미세혈관

9. 23.2 Vertebrate cardiovascular systems reflect evolution
A fish has a single circuit of blood flow
Heart: 1 atrium + 1 ventricle

11. The cardiovascular system of land vertebrates has two circuits
The pulmonary circuit
conveys blood between the heart and gas-exchange tissues
The systemic circuit
carries blood between the heart and the rest of the body
Mammal’s heart: 2 atria + 2 ventricles

12. Endotherms have higher metabolic rates than equal-sized ectotherms
Necessary to deliver more fuel and oxygen to body tissues
The circulatory system consists of two circuits
Artery : Aorta (대동맥), artery (동맥), arteriole (소동맥)
Vein : Vena cava (대정맥), vein (정맥), venule (소정맥)

13. THE MAMMALIAN CARDIOVACULAR SYSTEM
23.3 The human cardiovascular system illustrates the double circulation of mammals
The human heart is about the size of a clenched fist
The heart is formed mostly of cardiac muscle tissue
The right atrium and ventricle
Vena cava (superior and inferior)  right atrium right ventricle  pulmonary artery
The left atrium and ventricle
Pulmonary vein  left atrium  left ventricle  aorta

16. The valves in the heart
1. Semilunar valve
Located between the ventricle and the artery
Prevent backflow of blood from the artery to the ventricle
2. Atrioventricular valve
-Located between the atrium and the ventricle
-Prevent backflow of blood from the ventricle to the atrium

17. 23.7 The structure of blood vessels fits their functions
A single layer of epithelial cells forms capillary walls  simple squamous epithelium
The epithelium is wrapped in a thin basal lamina
Arteries and veins have smooth muscle and connective tissue in addition to the epithelium
Valves in veins prevent the backflow of blood

19. 23.4 The heart contracts and relaxes rhythmically
Cardiac cycle
Diastole
Blood flows from the veins into the heart chambers
Systole
The atria briefly contract and fill the ventricles with blood
Then the ventricles contract and propel blood out

21. Heart valves prevent backflow
The heart sounds we can hear with a stethoscope are caused by closings of the heart valves
Cardiac output
The amount of blood pumped into the aorta by the left ventricle per minute
Stimulants such as caffeine and exercize can increase cardiac output

22. 23.5 The pacemaker sets the tempo of the heartbeat
Pacemaker (sinoatrial node, SA node)
-It regulates the tempo of the heartbeat
-It is situated in the wall of the right atrium
It generates electrical signals

25. Atrium muscle cell들 사이에 전기신호가 전달
Atrium muscle cell과 ventricle muscle cell들 사이에 전기신호 전달 X (due to the presence of connective tissue)
The contraction of the ventricles
Pacemaker  atrioventricular node (AV node)  specialized muscle fibers (atrioventricular bundle [bundle of His], Purkinje fiber)  contraction of the ventricles

26. An electrocardiogram (ECG) is a recording of electrical changes in the skin resulting from the electrical signals in the heart
Control centers in the brain (medulla, 연수) adjust heart rate to body needs
Decrease in blood pH  medulla  nervous system  pacemaker  increase in heartbeat and the strength of ventricular contraction
Hormone (epinephrine, norepinephrine)
Nervous system (autonomic nervous system): sympathetic (up) and parasympathetic (down) division
Body temperature

27. 23.6 Connection: What is a heart attack?
A heart attack occurs when a coronary artery feeding the heart is blocked

28. 23.8 Blood pressure and velocity reflect the structure and arrangement of blood vessels
the force that blood exerts against the walls of our blood vessels
Pulse: the rhythmic streching of the arteries

29. Pressure is highest in the arteries
It drops to zero by the time the blood reaches the veins

30. Three factors keep blood moving back to the heart
muscle contractions
one-way valves
relaxation of heart and breathing

31. 23.9 Connection: Measuring blood pressure can reveal cardiovascular problems
Blood pressure is measured as systolic and diastolic pressures (normal blood pressure: 120/70 mmHg)

32. Hypertension is persistent systolic pressure higher than 140 mm Hg and/or diastolic pressure higher than 90 mm Hg
It is a serious cardiovascular problem

33. 23.10 Smooth muscle controls the distribution of blood
Muscular constriction of arterioles and precapillary sphincters controls the flow through capillaries
Precapillary sphincters
Thoroughfare channel
Thoroughfare channel
Arteriole
Venule
Arteriole
Venule
Capillaries 1 2
Sphincters relaxed
Sphincters contracted
Figure 23.11

34. Homeostatic control of blood pressure
*Baroreceptor
Specialized pressure-sensing nerve cells detect decreases in blood pressure
It is found in the walls of heart and the major arteries
Low blood pressure
Increase in cardiac output
Arterioles such as the skin and intestines constrict. Arteriolar constriction diverts blood to more critical organs
Veins constrict

35. 23.11 Capillaries allow the transfer of substances through their walls

36. The transfer of materials between the blood and interstitial fluid can occur by
leakage through clefts in the capillary walls (e.g.,water and small solutes such as sugars and salts)  blood pressure/osmotic pressure
diffusion through the wall
endocytosis/exocytosis

38. 23.12 Blood consists of cells suspended in plasma
STRUCTURE AND FUNCTION OF BLOOD
Blood consists of cells suspended in plasma
Blood = blood cells (45%) + plasma (55%)
Blood cells
Red blood cell (erythrocyte)
White blood cell (leukocyte)
Platelet

40. White blood cells help defend the body
5 major kinds of white blood cells (leukocyte)
Formed in the bone marrow
Basophil: release of histamine  dilation of blood vessels  allowance of other white blood cells to move out of capillaries and into surrounding tissues
Basophil
Eosinophil
Myeloid
leukocytes
Monocyte
Neutrophil
Lymphocyte

43. Neutrophil, monocyte: phagocytes
They eat bacteria, foreign proteins and debris from other body cells that have died
Eosinophil:
It kills multicellular parasites, related with allergic reactions
Lymphocyte:
Production of antibodies (B cell)
Attack pathogen-infected body cells and cancer cells (T cell)
Help activate B cells, T cells, and macrophage (T cell)
Natutal killer cell

44. 23.13 Two few or too many red blood cells can be unhealthy
Red blood cells contain hemoglobin – oxygen carrier
Lack nuclei and mitochondria
Formed in the bone marrow
Life span: 3-4 months
Old red blood cells are broken and their molecules are recycled in the liver and spleen
Anemia: an abnormally low amount of Hb or low number of red blood cells
Biconcave shape

45. Hypoxia conditions in tissues
(Low oxygen conditions)
Production of erythropoietin
In the kidney
Stimulation of the bone marrow
Production of more red blood cells
In the bone marrow

46. 23.14 Blood clots plug leaks when blood vessels are injured
When a blood vessel is damaged, platelets respond
They help trigger the formation of an insoluble fibrin clot that plugs the leak
Platelets derive from megakaryocytes in the bone marrow
Figure 23.16B

47. Figure 23.16A
Platelet releases chemicals that make nearby platelets sticky
Injury to lining of blood vessel exposes connective tissue; platelets adhere 1 2 3
Platelet plug forms
Fibrin clot traps blood cells
Connective tissue
Platelet plug
Clotting factors from:
Platelets
Damaged cells
Calcium and other factors in blood plasma
Prothrombin
Thrombin
Fibrinogen
Fibrin
Hemophilia

48. 23.17 Connection: Stem cells offer a potential cure for leukemia and other blood cell diseases
Multipotent stem cell  lymphoid stem cell, myeloid stem cell
Stem cells
in the bone marrow
(ribs, vertebrae, breast
bones, and pelvis)
Red blood cell
White blood cell
Megakaryocyte
platele