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Anatomy and Physiology 2 > Chapter 19 - Blood Vessels > Flashcards

Chapter 19 - Blood Vessels Flashcards

1
Q

Closed System

A

The blood never directly bathes the tissues, a small amount of fluid is forced across the walls of the capillaries and that is what bathes the tissues.

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2
Q

Dual Circulatory System

A

Two different circuits. The pulmonary circuit and the systemic circuit.

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3
Q

Pattern of Flow

A

Arteries carry blood away from the heart, they then divide into smaller arteries and then arterioles. The arterioles supply the capillaries and the capillaries are then drained by venules which join to form veins, which return the blood to the heart.

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4
Q

Structure of a blood vessel

A

Three layers, or tunics. The tunica intima, tunica media, and tunica adventitia

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5
Q

Tunica Intima

A

The innermost layer of the blood vessels. A simple layer of squamous epithelium, or endothelium. It is continuous throughout the heart and all the way to the capillary walls.

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6
Q

Tunica Media

A

Layer of smooth muscle and elastic fibers.

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7
Q

Tunica Adventitia (Externa)

A

A thin outer layer of connective tissue. It contains collagen and elastic fibers.

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8
Q

Elastic Arteries

A

Largest arteries in the body. Have a thick tunica media rich in elastic fibers, actually have more elastic tissue than muscle. The main arteries leaving the heart: the aorta, pulmonary trunk, pulmonary arteries, etc.

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9
Q

Muscular Arteries

A

Medium sized arteries. They distribute blood to the organs. They have more smooth muscle than elastic tissue. They constitute most of the named arteries.

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10
Q

Arterioles

A

Smallest arteries, their main function is to regulate the blood flow into the capillaries

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11
Q

Capillaries

A

Consist of nothing more than an endothelium, because of that they are able to move material across their walls.

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12
Q

Continuous Capillaries

A

Found in most parts of the body. The epithelial cells are held together by tight junctions

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13
Q

Fenestrated Capillaries

A

They have pores, which means they can have extensive filtration. Found in sites of heavy filtration, like the kidneys.

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14
Q

Sinusoidal Capillaries

A

Have wide flat channels through which blood flows very slowly. A special type of fenestrated capillary, found in the liver because of the extensive exchange.

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15
Q

Vasomotion

A

Blood flow through the capillaries is not a continuous flow, but a series of impulses. It can be controlled by a change in the concentrations of chemicals and gasses dissolved in the interstitial fluid.

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16
Q

Venules

A

Consist of endothelium surrounded by a small amount of connective tissue. As they get larger, they begin to have a tunica media.

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17
Q

Veins

A

They have all 3 layers, but the tunica media is very thin, only a few muscle cells, and the tunica adventitia is the thickest layer. THey are thin walled and more distensible than arteries. The tunica intima will form valves which prevent the backflow of blood.

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18
Q

Blood Flow

A

Represents the volume of blood passing though an area per unit of time.

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19
Q

Blood Velocity

A

The larger the cross-sectional area, the slower the flow.

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20
Q

Factors Which Affect Flow

A

Pressure- the energy imparted by the pumping of the heart

Resistance - The friction that blood has to overcome while traveling through the vessels

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21
Q

Types of Resistance

A

Blood viscosity - The blood’s internal resistance to flow

Vessel resistance - Vessel length, diameter, and turbulence.

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22
Q

Relationship between flow, pressure, and resistance

A

Flow is equal to pressure divided by resistance. In order for blood to flow, the pressure at the end of the vessel must be loss that at the beginning of the vessel.

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23
Q

Mean Arterial Pressure

A

The average between the two different blood pressure, systolic and diastolic.

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24
Q

Blood Pressure

A

Essential for blood flow. Refers to the arterial blood pressure. Two different values, systolic and diastolic, and expressed in mmHg. Ex: 120/80mmHg

25
Q

Pulse Pressure

A

The difference between systolic and diastolic pressure. Responsible for what we perceive as our pulse. A large difference means a strong pulse, a small difference creates a weak pulse.

26
Q

Factors That Affect Blood Pressure:

Blood Volume

A

The higher the volume, the greater the pressure

27
Q

Factors That Affect Blood Pressure:

Viscosity of Blood

A

The more viscous, the greater the pressure. Due mostly to the formed elements. The higher hematocrit, the higher viscosity.

28
Q

Factors That Affect Blood Pressure:

Elasticity

A

The elasticity of vessels buffers the blood pressure from having extreme systolic and diastolic numbers

29
Q

Factors That Affect Blood Pressure:

Gravity

A

Blood moving upwards has to work against the pull of gravity

30
Q

Factors That Affect Blood Pressure:

Cardiac Output

A

The more blood put into the arterial tree per minute, the greater the pressure

31
Q

Factors That Affect Blood Pressure:

Peripheral Resistance

A

The total resistance offered by the vascular network.

32
Q

Central Regulation of Blood Pressure

A

Nervous control. Precise homeostatic controls exist to maintain proper pressure and flow. Mainly regulate cardiac output and peripheral resistance.

33
Q

Vasomotor Center

A

Regulates the sympathetic activity of the ANS. Maintains adequate flow to the tissues. Innervates the smooth muscle layer of the vessels.

34
Q

Pressoreceptors

A

Detect any change in arterial pressure

35
Q

Chemoreceptors

A

If H+ levels are too high or O2 levels are too low, an impulse is sent to get the body to increase blood pressure. This speeds up the blood going to the heart and lungs to increase O2.

36
Q

Hypothalamus

A

Mediates the distribution of blood

37
Q

Hormonal Regulation by the Kidney

A

The kidney is very sensitive to reductions in blood flow. When flow drops below normal, the kidney releases Renin. Renin acts on Angiotensinogen to convert it to Angiotensin I and then Angiotensin II.

38
Q

Angiotensin

A

Increases blood flow by:

  • Causing vasoconstriction of the arterioles to increase peripheral resistance
  • Activating Aldosterone, which increases fluid volume by making the kidney retain salt and therefore water.
39
Q

Atrial Natriuretic Factor (ANF)

A

Hormone released by the atrial myocardial cells, it reduces aldosterone secretion and therefore increases the loss of salt and water. Resulting in a drop in blood pressure.

40
Q

Adrenal Medulla Hormones

A

Epinephrine and Norepinephrine increase cardiac output and vasoconstriction resulting in an increase in blood pressure.

41
Q

Antidiuretic Hormone (ADH)

A

Released by the hypothalamus. It regulates the fluid balance in the body. It promotes intense vasoconstriction and fluid retention when blood pressure drops.

42
Q

Autoregulation of Blood Pressure

A

Necessary to increase blood flow to selected tissues without changing the central blood pressure. Determined by the concentration of metabolic end products in the cells.

43
Q

Venous Blood Pressure

A

Much less uniform than arterial pressure, and much lower.

44
Q

Venous Blood Return

A

Brought about by two mechanisms:

  • Contraction of skeletal muscles
  • Siphon action
45
Q

Effects of Standing for Long Periods

A

Varicose veins - distended surface veinds due to blood pooling due to gravity.
Hemorrhoids - distended veins in the rectum.
Fainting - Loss of blood pressure to the brain due to pooling in the lower extremities.

46
Q

Distribution of Blood

A
  1. Venous side - 64%
  2. Systemic arteries - 17%
  3. Heart - 7%
  4. Systemic capillaries - 5%
  5. Pulmonary Veins - 9%
47
Q

Blood Reservoir

A

Because of their large capacity and small amount of contraction, the veins serve as a blood reservoir.

48
Q

Net Filtration Pressure

A

The capillaries are the site of exchange. Fluid is forced out of the capillaries by hydrostatic pressure and then into the capillaries by osmotic pressure. The difference between the two pressure is the net filtration pressure

49
Q

Hypertension

A

A blood pressure of 140/90 or higher. Leads to heart attacks, and strokes.

50
Q

Primary Hypertension

A

Dietary or exercise related

51
Q

Secondary Hypertension

A

Kidney tumors may lead to hyper aldosterone production. Tumors on the adrenal glands lead to higher epinephrine and norepinephrine production.

52
Q

Atherosclerosis

A

Narrowing of the arteries due to a build up of plaque. The major cause of strokes.

53
Q

Cholesterol

A

An essential lipid, part of membranes and a precursor for vitamin D. It’s insoluble in a water plasma so it must be combined with a lipoprotein to become soluble.

54
Q

LDL (Low Density Lipoprotein)

A

Most common, it functions to transport cholesterol to the cells. It must interact with a receptor on the cell. If there are too few receptors or if there are the correct amount of receptors, but a high fat diet, the receptors will be overcome, and LDL will build up in the blo.

55
Q

VLDL (Very Low Density Lipoprotein)

A

Transport triglycerides and a small amount of cholesterol

56
Q

HDL (High Density Lipoprotein)

A

The good kind! THey remove cholesterol from circulation and take it to the liver to be eliminated.

57
Q

Shock

A

Reduced cardiac output, or not getting enough blood to the tissues. Can be caused by heart failure, hemorrhage, reduced venous return due to massive vasodilation, etc.

58
Q

Edema

A

Accumulation of excess tissue fluid. Results in swelling and may impair transfer of materials.

59
Q

Hypotension

A

Extremely low blood pressure. In patients being treated for hypertension, who go overly aggressive. Anything below 100 mmHg systolic.

Anatomy and Physiology 2 (11 decks)

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