Examples of vascular resistance in the following topics:
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- They are the primary site of vascular resistance.
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- Resistance to flow must be overcome to push blood through the circulatory system.
- If resistance increases, either pressure must increase to maintain flow, or flow rate must reduce to maintain pressure.
- Numerous factors can alter resistance, but the three most important are vessel length, vessel radius, and blood viscosity.
- With increasing length, increasing viscosity, and decreasing radius, resistance is increased.
- The resistance offered by peripheral circulation is known as systemic vascular resistance (SVR), while the resistance offered by the vasculature of the lungs is known as pulmonary vascular resistance (PVR).
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- When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular resistance.
- When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance.
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- Bryophytes (liverworts, mosses, and hornworts) are non-vascular plants that appeared on earth over 450 million years ago.
- However, because they lack of lignin and other resistant structures, bryophyte fossil formation is improbable and the fossil record is poor.
- By the Silurian period, however, vascular plants had spread through the continents.
- This compelling fact is used as evidence that non-vascular plants must have preceded the Silurian period.
- Although the term non-tracheophyte is more accurate, bryophytes are commonly called non-vascular plants.
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- Key muscle groups and the associated vascular and
nervous systems can also be separated from other tissue, such as in the
upper arm.
- Muscle fascia is predominately composed of
cross-linked collagen and elastin fibers oriented parallel to the direction of
muscle force, making them able to resist high-tension forces while remaining somewhat elastic.
- Each individual fiber within a fascicle is
surrounded by a thin connective layer termed the endomysium, which
helps maintain close association between the muscle fiber and associated
vascular and nervous systems.
- It also maintains
the close association of the vascular and nervous system with the
muscle, which is required to deliver necessary metabolites and nerve impulses.
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- Venous pressure is the vascular pressure in a vein or the atria of the heart, and is much lower than arterial pressure.
- Venous pressure is the vascular pressure in a vein or the atria of the heart.
- This value is a function of the cardiac output (total blood pumped) and total peripheral resistance (TPR).
- TPR is primarily a function of the resistance of the systemic circulation.
- The latter can actively contract, reduce diameter, and increase resistance and pressure.
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- Seedless vascular plants, which reproduce and spread through spores, are plants that contain vascular tissue, but do not flower or seed.
- The vascular plants, or tracheophytes, are the dominant and most conspicuous group of land plants.
- By the late Devonian period, plants had evolved vascular tissue, well-defined leaves, and root systems.
- Seedless vascular plants are plants that contain vascular tissue, but do not produce flowers or seeds.
- In seedless vascular plants, such as ferns and horsetails, the plants reproduce using haploid, unicellular spores instead of seeds.
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- Clinical studies on mammals have shown that porous metals, such as titanium foam, may allow the formation of vascular systems within the porous area.
- For orthopedic uses, metals such as tantalum or titanium are often used because these metals exhibit high tensile strength and corrosion resistance, along with excellent biocompatibility.
- In addition, the porous structure allows for soft tissue adherence and vascularization within the implant.
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- Examples of risk factors include decreased immune system resulting from disease, compromised circulation caused by peripheral vascular disease, compromised skin integrity as a result of surgery, or repeated contact with contagious agents.
- One should not take antibiotics for longer than needed or when they are not needed—long term use of antibiotics leads to resistance and increased the chance of developing opportunistic infections like clostridium difficile colitis .
- Vaccination is another vital means of preventing infections by encouraging the development of immune resistance in vaccinated hosts.
- The organism forms large numbers of heat-resistant spores.
- Once spores are ingested by a patient, they pass through the stomach unscathed because of their acid-resistance.
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- Land plants, or embryophytes, are classified by the presence or absence of vascular tissue and how they reproduce (with or without seeds).
- Plants that lack vascular tissue, which is formed of specialized cells for the transport of water and nutrients, are referred to as non-vascular plants or bryophytes.
- Non-vascular embryophytes probably appeared early in land plant evolution and are all seedless.
- Lycophytes and pterophytes are both referred to as seedless vascular plants because they do not produce any seeds.
- Land plants are categorized by presence or absence of vascular tissue and their reproduction with or without the use of seeds.