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Biology 109 Test #3 > Circulation > Flashcards

Circulation Flashcards

1
Q

What are the basic roles of the circulatory system?

A
  1. Transporting oxygen and nutrients throughout body to tissues 2. Transport carbon dioxide and other waste to the respiratory system, digestive system, and the urinary system
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2
Q

What are the roles of the respiratory system?

A
  1. Take up oxygen 2. Release CO2
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3
Q

Must every organism exchange materials with its environment?

A

YES

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4
Q

What is the difference in how unicellular and multicellular organisms exchange materials with their environment?

A

Unicellular - Exchanges occur directly with environment Multicellular - Exchange directly with environment is not possible due to diffusion of gases longer than a few millimeters is much too slow.

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5
Q

Since multicellular organisms cant exchange material directly with their environment due to the slow process of long distance diffusion, what are the two solutions resulted from natural selection?

A
  1. Body size and shape that keeps cells in direct contact with environment: Cnidarians (jellyfish) and flatworms that have gastrovascular cavities.
  2. In most animals, transport systems connect organs of exchange with the body cells, this is mainly an internal transport system that circulates fluid.
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6
Q

What is the function of a gastrovascular cavity?

A

These function in digestion, circulation, and respiration.

Present in organisms with body shapes that allow for many of their cells to be in close contact with their environment.

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7
Q

Rather than having a simple gastrovascular cavity, more complex organisms need a circulatory system to trnasport and exchange nutrients, what are the two different types of circulatory systems these more complex organisms may have?

A

Open circulatory system

Closed circulatory system

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8
Q

What are the three basic components of a circulatory system?

A
  1. Fluid (blood or hemolymph)
  2. Tubes (vessels)
  3. Pump (heart)
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9
Q

What animals tend to have an open circulatory system?

A

Arthropods (grasshoppers, lobsters, crabs) and some Mulloscs (snails, slugs, clams, NOT SQUIDS OR OCTOPUS)

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10
Q

What is the circulatory fluid of an open-circulatory system calle? How does it differ from an open-circulatory systems fluid?

A

Hemolymph

This fluid is emptied into body cavities and bathes the organs directly which allows for exchange of nutrients between body cells. This fluid also acts as the interstitial fluid of the body.

As the heart relaxes the hemolymph is drawn back to the heart through pores.

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11
Q

What are some advantages of a open circulatory system that is described in class?

A

Not as much energy is required for these systems to function, likely due to lower hydrostatic pressures

Spiders use the hydrostatic pressure of the open circulatory system to extend their legs.

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12
Q

What animals tend to have a closed circulatory system?

A

Earthworms and Vertebrates

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13
Q

What is the fluid found in a closed circulatory system called? How does it differ from hemolymph?

A

Blood

Blood is confined to vessels and is different from the interstitial fluid. Exchange occurs between the blood and interstitial fluid, then again between the interstitial fluid and the body cells.

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14
Q

What are some advantages of a closed circulatory system?

A

Higher pressure of blood allows for better O2 and nutrient exchange in larger more active animals

Better regulation of distribution of blood to different organs.

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15
Q

In a vertebrate, what is another name for their circulatory system?

A

Cardiovascular system

Cardio = heart and vascular = vessels

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16
Q

What are the 6 different types of blood vessels described in class and a basic description of each?

A

Arteries - larger vessels that carry blood away form heart to organs

Arterioles - smaller vessels in comparison to arteries, carry blood to capillaries

Capillaries - microscopic vessels that are sites of gas and chemical exchange

Capillary Beds - networks of capillaries between blood and interstitial fluid

Venules - receive blood from capillaries

Veins - larger vessels that receive blood from venules, carry blood to the heart

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17
Q

What is the distinguishing factor between arteries and veins?

A

The direction they carry blood

NOT O2 CONTENT

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18
Q

What are the different chambers of the heart and a description of each?

A

Atria (singular: atrium) - Chamber that receives blood that is entering the heart.

Ventricles (singular: ventricle) - chambers that pump blood out of the heart.

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19
Q

Do the number of chambers in the heart as well as their degree of separation differ among vertebrates?

A

YES

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20
Q

What is single circulation? What vertebrates have this type of closed circulatory system? How many capillary beds does blood travel through before returning to the heart? How many chambers does the heart have? What is the oxygen content of the blood in the heart?

A

There is a single circuit that travels from the ventricle of the heart to not only to the gill capillary bed for gas exchange, but then to the body capillaries to distribute the O2 and nutrients before returning the the atrium of the heart. Meaning that the blood travels through two capillary beds before returning to the heart.

Heart consists of two chambers.

Bony fishes, sharks, rays

O2 content of blood in the heart is always poor

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21
Q

What is a closed circulatory system with double circulation? What vertebrates have this system? Describe the right side of heart and the left side of the heart in double circulation. How many pumps (hearts) do these types of circulations have?

A

There are two circuits of blood flow present.

Amphibians, reptiles, and mammals

One single pump (heart) used for both circuits

Right side: delivers O2 poor blood to the beds of gas exchange tissues (pulmonary circuit in mammals and reptiles)

Left side: pumps O2 rich blood that has returned from the pulmonary circuit to organs and tissues throughout the body. Also called the systemic circuit.

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22
Q

Describe the double circulation of an amphibian. How does it differ from a mammalian double circulation?

A
  • Amphibians have a 3 chambered heart (2 atria and 1 large venticle)
  • Some mixing of O2 rish and O2 poor blood may occur (about 10% of each), but 90% of O2 rich and O2 poor blood remains divided by a ridge in the ventricle that directs each to their respective circuit.
  • O2 poor goes to a pulmocutaneous circuit, O2 rich goes to systemic circuit.
  • When in water, they can shunt circulation from the ineffective lungs and favor their cutaneous circulation.
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23
Q

How does the double circulation of turtles, snakes, and lizards differ from mammalian double circulation?

A

They also have a 3 chambered heart, but differ from amphibians in that they have an incomplete septum that partially divides the ventricle.

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24
Q

Describe the mammalian and bird double circulation. How many chambers? Complete septum? How does the 4-chambered heart of the mammal differ from the 4-chambered heart of crocodilians and why?

A

4 chambered heart:

Right side: receives O2 poor blood from body and pumps it to lungs

Left side: Receives O2 rich blood from lungs and pumps it to body.

Complete septum divides venticles.

Crocodilians also have 4 chambered heart, but pulmonary and systemic circuits are connected where the arteries exit the heart. This allows for blood to be shunted from pulmonary circuit when underwater and not using lungs.

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25
The fact that birds and mammals come from different tetrapod ancestors but both show the same 4 chambered heart double circulation is an example of what?
Covergent evolution
26
List the 6 steps of mammalian circulation as discussed in class starting with the blood in the right ventricle.
1. RV pumps blood to the lungs. 2. In the lungs, the blood loads O2 and unloads CO2. 3. O2-rich blood returns from lungs via pulmonary veins to LA. 4. O2-rich blood flows into LV. 5. LV pumps O2-rich blood out through the aorta to the heart muscle itself and body tissues. 6. Blood returns to the heart (RA) through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs).
27
What are the two parts of the cardiac cycle?
Contraction (systole) - pumping blood out Relaxation (diastole) - filling chambers with blood More specific: 1. Atrial and ventricular diastole - passive filling of ventricles through atria 2. Atrial systole and ventricular diastole - brief atrial systole that pumps remaining atrial blood to ventricle 3. Ventricular systole and atrial diastole - ventricular contraction pumps blood to respective circuits, atria filling
28
What are the four valves of the heart that prevent backflow of blood?
Semilunar valves (located at exits of heart): Pulmonary: between RV and pulmonary artery Aortic: between LV and aorta Atrioventricular valves: Tricuspid: between RA and RV Mitral (bicuspid): between LA and LV
29
What causes the lub sound in in a heartbeat?
recoil of blood against the AV valves.
30
What causes the dup sound in a heartbeat?
recoil of blood against the semilunar valves
31
What is it called when there is a sound of blood backflowing through a defective heart valve?
Heart murmur
32
What is heart rate? Stroke volume? How do you calculate cardiac output?
number of heartbeats per minute, also called pulse volume of blood pumped in single contraction CO = HR x SV
33
Does CO remain constant? What is the relationship between HR and SV?
YES Inverse relationship, this allows for a constant CO to be maintained HR 72 x SV 70 = CO 5 L/min
34
What is cardiac output? How is it calculated?
The volume of blood pumped into the systemic circulation per minute. CO = HR x SV
35
What is the average stroke volume in humans?
70ml
36
What does it mean when it is said that some of the cardiac muscle cells are autorhythmic? Does this mean that the nervous system has no control over the heartrate?
muscles cells contract not by a impulse generated by the nervous system, but by a self-generated impulse. The nervous system can still control the heartrate.
37
What is the pacemaker of the heart? What does this mean?
SA (sinoatrial) node. This autorhythmic node sets the rate and timing of cardiac muscle cell contraction, begins by contracting both atria in unison and impulse goes the the rest of the heart in a coordinated and rapid fashion.
38
What is an EKG (electrocardiogram)?
A way of detecting the currents that are conducted to the skin from the heart by placing electrodes on the skin.
39
Describe electrical conduction in the heart starting with the SA node.
SA fires – atria contract To AV node – pause To Bundle branches through septum (ventricles begin contraction at apex) To Purkinje fibers (travels up walls of ventricle rapidly for contraction)
40
What are some things that influence the pacemaker (4)?
Nerves - sympathetic and parasympathetic hormones - epinephrine body temperature exercise
41
Arteries and veins have three tissue layers, what are the types of each starting inside and working out?
Inner: Endothelium (simple squamous) Middle: Smooth muscle (involuntary) Outer: Connective tissue
42
What are some differences between arteries and veins besides the direction of blood flow?
Arteries: thick walls to accomodate BP generated by heart, thick smooth muscle layer that controls flows to different parts of the body Veins: Thinner walls, lower-velocity and pressure, valves present to maintain unidirectional flow.
43
What is the purpose of the elastic fibers of the arteries and veins?
These allow for them to stretch (to accomodate pressure from heart contraction) and recoil (also helps to push blood along after contraction).
44
Describe capillaries and how they differ from veins and arteries?
- Only have endothelial walls (1 cell layer thick) to allow for diffusion of gases and other chemicals
45
What is bloodflow through a vessel analogous to?
Water flowing through a hose. MEANING HIGH PRESSURE TO LOW PRESSURE
46
Where is velocity of blood flow the highest? Lowest?
Highest: Areteries Lowest: Capillaries
47
Why is blood velocity the slowest in the capillaries? What is the purpose?
High resistance and large total cross-sectional area of the capillary beds This slow velocity allows time for the transfer of substances between the blood and interstitial fluid.
48
Understand the relationships between cross-sectional area, blood flow velocity, and blood pressure.
Use this picture to understand this relationship.
49
What type of pressure is blood pressure and where is it exerted?
this is a hydrostatic pressure that is exerted on the wall of the blood vessel.
50
What is happening to the vessel walls during systole and diastole?
Systole - stretching Distole - recoil Important in maintaining blood pressure and blood flow.
51
Describe systolic pressure, diastolic pressure, and pulse.
Systolic pressure - pressure in arteries during ventricular systole, this is the highest pressure in the arteries Diasolic pressure - pressure of arteries during diastole, lower than the systolic pressure Pulse - rhythmic bulging of artery with each heartbeat that can be felt
52
How is blood pressure determined?
By CO and peripheral vascular resistance due to the diameter of the arterioles.
53
What is vasoconstriction? What are some chemicals that promote this (2)?
The contraction of the smooth muscle in the arterioles that increases blood pressure. Two peptides: endothelin and angiotensin II are both potent vasoconstrictors
54
What is vasodilation? What are some chemicals that promote this (2)?
the relaxation of smooth muscles of arterioles that causes blood pressure to fall histamines and nitric oxide (gas) are potent vasodilators
55
What is a sphygomonameter? How is it used? How is BP different in brain?
A blood pressure cuff. BP is about 27mmHg less in brain than near heart Measured using artery usually in arm that is at the same height as the heart.
56
Is the blood pressure in veins high or low?
Low
57
What are four mechanisms that assist in the return of venous blood to the heart?
One-way valves in veins Rhythmic contraction of smooth muscle in the walls of venules and veins Contraction of skeletal muscle Expansion of the vena cavae and other large veins during inhalation
58
Describe the distribution of blood flow in the capillaries. How is blood flow in capillaries altered?
Only 5-10% of capillaries have blood flowing through them at a given time, though, the capillaries of major organs are usually filled to capacity. Two ways blood flow in capillaries is altered: 1. Contraction of smooth muscle layer in wall of arteriole adjoing a capillary bed. 2. Action of the precapillary sphincters at the entrance of capillary beds.
59
Where does the exchange of substances between blood and interstitial fluid take place?
Across the thin endothelial walls of the capillaries.
60
What two pressures dictate the movement of fluid between capillaries and surrounding tissues?
1. High hydrostatic blood pressure in capillary drive fluid out on the arterial end 2. At the venule end the hydrostatic blood pressure is lower in the vessel, and the blood proteins pull fluid into the vessel via osmotic pressure.
61
Do blood proteins and blood cells readily pass through the capillary endothelium?
NO NO NO
62
Describe the function of the lymphatic system. What is its fluid called?
Network of vessels that returns water and proteins back to the circulatory system. Fluid is called lymph.
63
What is a lymph node?
This is a small mass of tissues that are situated along the network of lymphatic vessels that filter the lymph. Lymph nodes also house cells that attack viruses and bacteria.
64
Look at this picture of the content of blood and become familiar with it. What percentage of blood is plasma and what percentage is cellular (formed) elements?
55% plasma and 45% cellular (formed) elements
65
What does plasma consist of?
1. Mostly water with dissolved ions, nutrients, O2 2. Plasma proteins: - Albumin (osmotic balance) - Fibrinogen (blood clotting) - Immunoglobulin/antibodies (defense)
66
What does serum mean?
Blood plasma without blood clotting factors
67
What are the three components of the Cellular (formed) elements?
1. Erythrocytes (RBCs) 2. Leukocytes (WBCs) 3. Platelets
68
What are some characteristics discussed about erythrocytes in class?
Most numerous blood cell type in the blood doughnut-shaped to enhance diffusion transport O2 via hemoglobin lack a nucleus and mitochondria
69
What are some characteristics discussed about leukocytes in class? What are the 5 types?
account for \<1% of cells in blood function in defense and immunity 5 types: basophils, eosinophils, neutrophils, monocytes, lymphocytes
70
+What are some characteristics of platelets that were discussed in class?
These are pinched off fragments of megakaryocytes function in blood clotting lack a nucleus
71
What is a stem cell? Where are stem cells that make blood cells found? What is special about their mitotic process?
An undifferentiated cell that can reproduce indefinitely. They are found in the bone marrow. When they divide they produce one identical duaghter cell and one cell that is specialized.
72
What is the difference between a myeloid and a lymphoid stem cell?
Myeloid - produce erythrocytes, platelets, and all WBCs except lymphocytes. Lymphoid - produce T and B cells (lymphocytes)
73
What is hematopoiesis?
The production of blood cells in the bone marrow.
74
Are blood cells and platelets being constantly replaced? What is the typical lifetime of a RBC?
YES 3 months
75
What is the term used for the production of RBCs (erythrocytes)? What hormone controls this and where is it produced? What triggers it to be produced?
Erythropoiesis Erythropoietin (EPO) - produced in the kidneys in response to low O2 levels. EPO can be used to treat conditions like anemia, also used by athletes to blood dope (bad consequences).
76
What is coagulation? What is a static blood clot formed within a blood vessel called?
This is the formation of a solid clot from liquid blood. This is a cascade of complex reactions that ultimately leads to a fibrin clot due to the inactive fibrinogen being converted to fibrin. A thrombus.
77
What is haemophilia?
Someone with mutations in genes that code for certain clotting proteins.
78
What is cardiovascular disease defined as? Is it the #1 cause of death in the US?
A range of disorders that affect the heart and blood vessels. YES
79
What is the estimated percentage of cardiovascular diseases that are considered preventable?
90%
80
What is the primary player related to the development of most CVDs?
Cholesterol.
81
What are the two types of cholesterol and their function? What is the ratio of the two that strats to cause problems?
Low-density lipoprotein (LDL) - delivers cholesterol to all cells (bad cholesterol) High-density lipoprotein (HDL) - delivers cholesterol to the liver (good cholesterol) A high ratio of LDL to HDL is when problems arise.
82
What is a new markers that is being considered when screening for risk of CVD?
Apoplipoprotein B - a protein that binds to both HDL and LDL
83
What are the 3 mains CVDs that we cover for this class?
Atherosclerosis Heart attack Stroke
84
What is atheroscleosis vs arteriosclerosis?
Atherosclerosis - the buildup of plaque deposits within the arteries that narrows lumens and impedes blood flow. Arteriosclerosis - the hardening of arteries caused by a decrease in elasticity
85
What is a plaque composed of?
lipids (mainly LDL cholesterol) and fibrous connective tissue that grows along arterial walls.
86
What is a myocardial infarction?
The damage or death of cardic muscle tissue resulting form blockage of one or more coronary arteries by a thrombus.
87
What is angina pectoris?
Chest pain that is an indicator of insufficient blood supply to the heart.
88
What happens to the dead cardiac muscle after a heart attack? What is this process called?
It is replaced with scar tissue composed primarily of collagen (same as scar on skin for most part) This process is called fibrosis.
89
Refer to the picture. After fibrosis occurs in this left ventricular what is the result of the structure of the LV?
The left ventricle lumen is larger but there is much less muscle mass present to be able to properly pump.
90
What is a stroke? What are the two types of stroke that can occur?
Stroke - the death of nervous tissue in the brain due to a lack of O2. 2 Types: - Ischemic - Blood clot impedes blood flow, either by a thrombus or an embolus. - Hemorrhagic - Blood vessel ruptures and blood leaks into brain tissue.
91
What is a TIA?
Transient (temporary) ischemic attack
92
What is the difference between an embolism and a thrombus?
Thrombus - A static blood clot that forms within a blood vessel. Embolus - a traveling blood clot.
93
What does HTN contribute to?
Atherosclerosis Increases risk of CVA and MI
94
Other than HTN, what are some other risk factors of CVD?
- heredity - diet - lack of exercise - smoking
95
What are some treatments of CVD?
statin drugs (lower LDL, increase HDL) aspirin stents
96

Biology 109 Test #3 (5 decks)

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