Chapter 48: Circulatory Systems

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1

What is. the primary function of the circulatory system?

Transport necessary materials to the cells of an animal's body

Transport waste products away from cells so. they can be released into the environment

2

What are the two main types of circulation?

Open and Closed

3

What are the three components of circulatory systems

1. Fluid containing cells and solutes

2. System of vessels, hollow tubes through with the fluid travels

3. One or. more muscular structures such as a heart. that pumps fluid through the vessels

4

In an open circulatory system what happens with the fluid?

Hemolymph (fluid) is pumped bone or more hearts through vessels that open into the animal's body cavity

5

How are nutrients and wastes exchanged in an open. circulatory system?

By diffusion between hemolymph and body. cells

6

What is the pro of the open circulatory system? The con?

Pro: Metabolically inexpensive

Con: Cannot divert hemolymph to specific tissues

7

What are examples of organisms who have an open circulatory system?

Arthropods and come mollusks

8

In a closed circulatory system what is separated?

Blood and interstitial fluid

- Differ in components and chemical composition

9

Where is a closed. circulatory. system found?

In earthworms, cephalopods, and all vertebrates

10

What. are the 7 key features of the closed circulatory system?

  1. Blood is pumped under pressure to one ormolu contractile, muscular hearts
  2. Blood remains within vessels for distribution
  3. Solutes exchanged with environment. and body cells
  4. Blood contains. disease-fighting. cells and molecules
  5. Can be. adjusted. to watch the animal's metabolic demands
  6. Capacity to heal themselves when wounded (clots)
  7. System grows in size as animal grows
11

What are the two advantages of the closed circulatory system?

Animal can grow larger with more efficient supply

Blood flow can be selectively controlled

12

In the fishes single circulation, what is. the purpose of the single atrium?

Collects. blood to form tissues

13

In the fishes single circulation, what is the purpose of the ventricle?

Pumped blood out of the heart

14

In the fishes single circulation, what is the purpose of the arteries?

Carry the blood away from the heart to the gulls.

15

In the fishes single circulation, what. is the purpose. of veins?

Returns partially deoxygenated blood to the heart

16

What does the blood do In the fishes single circulation

Picks up oxygen, drops of carbon. dioxide and goes on through arteries to other body tissues

17

(T/F)The heart doesn't generate high pressure?

True

18

In the fishes single circulation, what limits the rate of circulation?

The rate at which oxygenated blood can be delivered to body cells

19

What organisms have a double circulation?

Crocodiles, birds, and mammals

20

What does "double" circulation mean?

Oxygenated and deoxygenated blood separate into two distinct circuits

21

What is pulmonary. circulation?

Blood. pumped to lungs, then back to heart

22

What is systematic circulation?

Blood pumped to the body, deoxygenated blood delivered back to heart

23

What is the major advantage of double circulation?

2 different blood pressures in two different systems

24

What system adaptations do closed circulatory systems undergo?

Sleep, activity, and emergencies

25

What is exercise controlled by?

Vasodilation and. vasoconstriction

26

What is epinephrine?

A hormone from adrenal gland that increases cardiac output (increasing stroke volume and/or. heart rate)

27

What are baroreceptors?

Stretch receptors in certain arteries (aorta. and carotid) that communicate with brain to signal when blood pressure is outside the normal. range

28

What might occur when your blood pressure decreases?

Dehydration or hemorrhage

29

What. are the four components of blood?

1. Plasma

2. Leukocytes

3. Erythrocytes

4. Platelets/thrombocytes

30

What is plasma composed of?

Water, nutrients, oxygen, waste, and hormones

31

What is leukocytes composed of?

white blood cells

32

What is erythrocytes composed of?

Red blood cells

33

What is the function of plasma?

Functions in buffering, fluid balance, and transport of cells and proteins

34

What is the function of leukocytes?

Defend body against infection and disease

35

What is the function of erythrocytes?

Oxygen transport using hemoglobin

36

What is the function of platelets/thrombocytes?

Formation of blood clots

37

What do. all vertebrate hearts have?

At least one anterior atrium and one lower ventricle

38

What separates atria and ventricles when more than one is present?

Septum

39

Where does the blood enter?

From systematic or pulmonary veins into atrium

40

Blood enters the vertebrate heart through? And goes out through?

In: one-way atrioventricular (AV) valves into ventricles

Out: one-way semilunar valves into aorta (systematic) or pulmonary trunk

41

How is the myogenetic heart excitable?

Electrically

42

What muscle is the signaling mechanism that initiates contractions?

Cardiac muscle

43

What kind of hearts require regular electrical impulses from the nervous system?

Neurogenic hearts

44

What kind of hearts do all vertebrates have?

Myogenic heart

45

What are cardiac muscle cells called?

Myocytes

46

When a bunch of myocytes forms an interlocking network, what is created?

Rapid spread of electric current

47

What can increase or decrease rate?

Nervous input

48

How can a myogenic heart beat on its own if dissected out of an animal?

If it is placed in a nutrient bath

49

What are the two phases of the excitation of the vertebrate heart?

1. Atrial phase

2. Ventricular Phase

50

What. happens in the atrial phase?

Electrical signals generated at sinoatrial node (SA node)

  • Action potentials spread quickly through gap junctions
  • Both atria contract together forcing blood through AV valves into ventricles
51

What happens in the Ventricular Phase?

Electrical impulses reach atrioventricular (AV node)

  • Conducts impulse from stria to ventricles
  • Both ventricles contract together through Purkinje fibers
52

What cycle produced a single heartbeat?

Cardiac cycle

53

What are the two phases of the cardiac cycle?

Diastole and Systole

54

What is the diastole?

Ventricles are relaxes and fill with blood coming from the atria

55

What is the systole?

Ventricles contract and. blood is ejected through semilunar valves

56

When blood pressure is the lowest what phase is the cardiac cycle in?

Diastole

57

When blood pressure is the highest what phase is the cardiac cycle in?

Systole

58

Heart valved open and shut in response too?

Pressure gradients

59

What are arteries? What do they do?

Layers of smooth muscle and connective tissue around smooth endothelium

Conduct blood away from the heart

60

Wall of the largest arteries are made of what?

Elastin

61

What are arterioles? What do they. do?

Formed as arteries branch repeatedly and become narrower

Can dilate or constrict to control blood distribution to tissues

62

What are capillaries?

Site of gas and nutrient/waste exchange

63

What are continuous capillaries?

Smooth walls and small number of tiny openings

64

What are fenestrated capillaries?

Numerous larger holes

65

What are the narrowest vessels in the body?

Capillaries

66

How does blood enter a capillary?

Under pressure

  • Pressure forces some water out through openings in capillary walls. and into interstitial fluid (but not red blood cells or large proteins)
67

Most of the fluid that leaves is __________ at the end of the capillary?

Recaptured

  • Pressure decreases along the capillary
  • Proteins in the blood create an osmotic force that draws fluid back into blood
68

What is the purpose of the lymphatic system?

Collects fluid is not captured and will return it to the blood

69

What are venules?

Small, thin extensions of capillaries

70

What are veins and what do they do?

Thinner and less muscular than arteries that conduct blood back to the heart

71

Why are veins needed?

Returning of blood to the heart because residual blood pressure is very low

  • Smooth muscle contractions help propel blood
  • Veins squeezed by skeletal muscles
72

What is responsible for blood flow?

Blood pressure

73

Why is blood pressure and blood flow not equal in all regions of an animal's body?

Because of resistance

74

What is Resistance (R)?

Tendency of blood vessels to slow down the flow of blood

75

Is blood pressure higher in arteries or in veins?

Arteries

76

What is resistance a function of?

Vessel radius, length, and blood viscosity

77

What is a major mechanism controlling blood flow to a region?

Change in arteriolar resistance

78

What. is vasodilation?

Increase in radius

79

What is vasoconstriction?

Decrease in radius

80

What is resistance to flow controlled by?

Locally produced substances, hormones, and nervous system input

81

What is Cardiac output (OC)?

Amount of blood the heart pumped in liters/minute

82

What does Cardiac output depend on?

Size of the heart, how often it beats each. minute, and how much blood it ejects

83

What is stroke volume?

Amount of blood a heart ejects at each beat

84

What isCardiovascular disease?

Disease of the heart and blood vessels accounts for more deaths each year in the US than any other cause

85

What is Hypertension?

High blood pressure

86

What is a normal resting blood pressure?

Above 140/90 mmHg

87

What are causes of hypertension?

Obesity, smoking, aging, etc.

88

How can hypertension be treated?

With. diet, exercise, and drugs

89

What can hypertension damage in the future?

Formation of plaques and atherosclerosis

90

What is Myocardial infraction (MI) - heart attack usually caused by?

Blockage of one of the coronary arteries

91

What can serious. heart attacks lead. to?

Significant. damage or death to the heart

92

Does dead cardiac muscle regenerate?

No

93

What is the. purpose of coronary artery bypasses?

Usage of a healthy blood vessel to replace a blocked coronary artery