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Biology 20 > Circulatory > Flashcards

Circulatory Flashcards

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1
Q

Arteries

A
  • thick blood vessels that carries blood away from the heart
  • every time the heart contracts, blood surges from the heart and enter the arteries
    -the arteries stretch order to accommodate the inrush of blood
    -each organ in the body is supplied with one or more arteries
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2
Q

How are arteries adapted to withstand the pressure?

A

-have the thickest walls composed of distinct layers
- outer and inner layers of connective tissue
-middle layer of muscle fibres and elastic connective tissue

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3
Q

What is the pulse that you feel?

A

It is created by the changes in diameter of the arteries following heart contractions

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4
Q

What is the Tunica Externa?

A

The tough outer layer of connective tissue in the arteries

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5
Q

Tunica media

A

Thick Layer of smooth Muscle and elastic fibres composed of the protein elastin

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6
Q

Tunica intima

A

Smooth endothelium that lines the interior of the artery

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7
Q

Lumen

A

The inside space of a tubular structure, usually artery or vein

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8
Q

In the tunica media, what does the elastin do?

A

Elastin is organized into fenestrated cylindrical lamellae and is separated by other lamellar layers by smooth muscle. As it is stretched, it stores this energy and then recoils back to help propel the blood through the artery

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9
Q

In the tunica media, what does the smooth muscles do?

A

Contraction of the smooth muscle in the artery controls the diameter of the lumen as well as the rigidity, regulating flow

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10
Q

What does the tunica external do?

A

Helps prevent aneurisms and bursting due to high pressure

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11
Q

How is the progress of blood along the major arteries?

A

Artery walls work with the pumping of the heart to facilitate blood flow, the progress of blood along major arteries is pulsatile! The pulse reflects each heart beat.

Pulsatile: beating or moving with a strong regular rhythm, especially in the way that the heart beats

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12
Q

How does the contractions and relaxations of the arteries reflect the heart beat?

A

The peak pressure in an artery (SYSTOLIC PRESSURE) is associated with the CONTRACTION of ventricles of the heart. This causes the lumen to widen and stretched the elastic fibres in the wall, storing potential energy

Following this contraction, RELAXATIONS of the heart muscles results in the lowest pressure and is referred to as DIASTOLIC PRESSURE. The stored potential energy is released through the restoration of elastic fibres to their original position, driving the blood forward through the vessel.

This saves energy and prevents pressure within the artery from becoming too low. Pressure in the arteries are maintained so the blood flow is relatively steady and continuous even with a pulsating heart beat.

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13
Q

Vasoconstriction

A

A nerve impulse causes smooth muscle in the arteries to contracts, reducing the diameter of the blood vessel and blood flow to tissues.

Can be regulated with hormons

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14
Q

Vasodilation

A

Relaxation of the smooth muscle causes dilation of the arterioles, blood flow increases and there is an increases in the delivery of blood to tissues. This, in turn, permits the cells in that localized area to perform energy-consuming tasks

Can be regulated by hormones

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15
Q

Arterioles

A

Smaller arteries essentially

As blood passes from the arteries, they flow into arterioles

Their structure is similar to arteries, with a middle layer composed of elastic fibres and smooth muscle

Arterioles leading to capillaries are only open when the cells in that area requires blood

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16
Q

What regulates the diameter of arterioles

A

Automatic Nervous System

17
Q

____________________ is responsible for redness in skin due to blushing

A

Vasodilation-increase in blood flow to capillaries helps to release excess heat

18
Q

______________ is responsible for paleness due to being frightened

A

Vasoconstriction- decrease in blood flow to outer capillaries and diverted to muscles, provide more energy and gluscose to muscles

19
Q

Capillaries

A

-connect arterioles to venules
- composed of a single layer of endothelium cells and the narrowest blood vessels in the body
-only one red blood cell through at a time
-site of fluid and gas exchange (consists of several branches to increase surface area for gas and fluid exchange - branch and rejoin repeatedly to form a capillary network)

  • spaces exist where vitamins and minerals can be exchanged
20
Q

Tissue Fluid

A

When plasma leaks through into the tissues

Contains dissolved oxygen, glucose and other substances to nourish cells in three tissues.

As the tissue fluid flows between the cells in these tissues, waste products excreted by these cells are absorbed and taken away as the tissue fluid flows reenters the capillary network

21
Q

Weaknesses of Capillaries

A

Supseptible to damage by pressure or trauma because of how thin they are

22
Q

Permeability of Capillary Walls

A

-differs a,longstanding different tissues, selectively allowing certain large particles to reach certain tissues and not others. Permeability can also change over time and the capillaries can be repaired and remodelled in response to the needs of tissues

23
Q

Atherosclerosis

A

Excess lipids in the blood can be deposited in the walls of the arteries-narrows the inside diameter of arteries

Deposition of calcium and minerals results in a plaque being formed

Results in HIGH BLOOD PRESSURE

If the plaque grows so big that it bursts the artery wall, clotting could result in the blockage of artery, which could lead to a heart attack.

24
Q

Atheroma

A

The development of fatty tissue occurs within the endothelial layer (adjacent to the artery wall)

25
Q

How is atheroma formed?

A

Caused by the accumulation of LDL that contain fats and cholesterol

The endothelium and smooth muscle then send signals to phagocytes(macrophages)

PHAGOCYTES then engulf the fats and cholesterol through endocytosis

The macrophages become very large and turn into FOAM CELLS, which have a limited ability to migrate. As such they remain there and initiate pro inflammatory responses, ultimately leading to the progression of the plaque

Smooth muscle cells migrate over the atheroma, forming a tough cap, which then causes a bulge into the lumen, narrowing the artery

26
Q

Coronary Occlusion

A

A complete or partial blockage in your coronary arteries

27
Q

Anoxia

A

Oxygen and nutrients may not supply heart muscle if coronary occlusion occurs, resulting in pain called ANGINA

Interference of the heart muscle contractions due to the anoxia causes the heart to beat faster to maintain blood circulation. This increased pressure can cause the cap covering the atheroma to rupture, resulting in the formation of blood clots and blockage of the artery, leading to death of heart muscle.

28
Q

Factors that lead to the development of Atheroma

A
  • high blood concentrations of LDLs
    -chronic high blood glucose concentration (overeating, obesity, diabetes)
    -chronic high blood pressure (smoking and stress)
    -consumption of trans fats
    -infections of artery wall by microbes(eg. Chlamydia pneumoniae)
    -production of trimethylamine N-oxide TMAO by intestinal microbes
29
Q

Aneurysm

A

Bulge that forms in the walls of a weakened blood vessel
Can be caused by atherosclerosis
Rupture of thinner wall leads to hemorrhaging, less oxygen and nutrients being delivered to cells - cell death
Aneurysms in the brain can cause strokes

30
Q

Venules

A
  • contain smooth muscle
  • capillaries merge into
  • contain one way valves
31
Q

Vein

A

thinner than arteries
carry blood toward the heart
Under low pressure
Less muscle and elastic fibres

32
Q

What are valves used for?

A

Prevent back flow

33
Q

hepatic portal vein

A

Takes blood from the stomach and intestines to the liver instead of the heart

Biology 20 (6 decks)

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