/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 138 Describe the cardiovascular coun... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 11: Problem 138

Describe the cardiovascular counter-current mechanism in the human body.

Short Answer

Expert verified
Answer: The primary purpose of the cardiovascular counter-current mechanism is to maintain and regulate body temperature efficiently by conserving heat and minimizing heat loss to the environment. This is achieved by transferring heat from warmer blood to cooler blood in close proximity within the blood vessels.

Step by step solution

01

Introduction to Counter-Current Mechanism

The cardiovascular counter-current mechanism is a biological system present in the human body that helps maintain and regulate body temperature efficiently. This mechanism is crucial for conserving heat and minimizing heat loss to the environment.
02

Purpose of Counter-Current Mechanism

The primary purpose of the cardiovascular counter-current mechanism is to maintain and regulate body temperature in a way that conserves heat and minimizes heat loss to the environment. This is achieved by transferring heat from warmer blood to cooler blood in close proximity within the blood vessels.
03

Components of the Counter-Current Mechanism

The key components of the cardiovascular counter-current mechanism are the blood vessels, specifically arteries and veins. Arteries carry warm blood from the heart to the extremities and other parts of the body, while veins carry cooler blood back to the heart.
04

Functioning of the Counter-Current Mechanism

The counter-current mechanism functions through the close physical proximity of arteries and veins. When warm blood flows from the heart through the arteries towards the extremities (such as hands and feet), it comes into close contact with the veins carrying cooler blood back to the heart. As these blood vessels are in close proximity, heat from the warmer arterial blood gets transferred to the cooler venous blood, effectively pre-warming it before it reaches the heart. This exchange of heat helps to conserve overall body heat and minimize heat loss.
05

Counter-Current Mechanism in Different Conditions

The efficiency of the counter-current mechanism varies depending on the environmental temperature and the individual's level of activity. For example, the mechanism is more efficient in warmer environments as there is less need for heat conservation. Conversely, when the body is exposed to cold environments or when a person is engaging in physical activity, the counter-current system becomes more active to conserve heat and maintain body temperature.
06

Importance of the Counter-Current Mechanism

The cardiovascular counter-current mechanism plays a crucial role in the human body by ensuring an efficient regulation of body temperature. By conserving heat and minimizing heat loss, this system helps maintain an optimal internal environment for the proper functioning of various body processes and overall survival.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Cardiovascular System
The cardiovascular system, sometimes known as the circulatory system, is vital for the body. It consists of the heart, blood vessels, and blood. This system transports nutrients, oxygen, and hormones to cells and removes waste products like carbon dioxide. A unique feature of the cardiovascular system is its ability to regulate temperature through different mechanisms, including the counter-current mechanism.
This method is particularly crucial in maintaining stability in the body's internal environment. With arteries and veins positioned closely together, this mechanism allows for efficient transfer and exchange of heat. This helps in conserving body heat by warming the blood returning to the heart.
Body Temperature Regulation
The human body continually works to maintain a stable core temperature, crucial for enzymatic and cellular functions. Temperature regulation refers to how our body adjusts to internal and external changes to sustain this balance.
Several systems, including cardiovascular, play crucial roles. For example, when you are in a cold environment, your body strives to keep your core warm by restricting blood flow to the extremities. This ensures less heat is lost to the surrounding, keeping vital organs warm.
Additionally, this mechanism actively engages when exercising. It operates to dissipate excess heat generated from muscle activity while also ensuring your overall body temperature remains within safe limits.
Heat Conservation
Heat conservation is essential in colder climates and during periods of inactivity to maintain body temperature. The counter-current mechanism plays a critical role here. By positioning arteries and veins close to each other, the body efficiently transfers heat from warmer arterial blood to cooler venous blood.
This proximity ensures that the returning blood is pre-warmed before it reaches the heart. Since heat is energy, this method reduces the amount of heat 鈥� and therefore energy 鈥� lost to the environment, improving efficiency.
This adaptive process is always in motion, adjusting dynamically to changes in the external environment or the physical state.
Biological Systems
Biological systems encompass complex networks of organs and functions working towards maintaining life. In terms of regulating body temperature, the interplay of various systems is crucial.
The cardiovascular system contributes significantly to this regulation through mechanisms like the counter-current exchange. Biological systems interact in such a way that optimizes the body's efficiency. For instance, in cold conditions, not only does the cardiovascular system conserve heat, but your skin's blood vessels constrict to minimize heat loss.
Overall, these systems highlight the body's intricate and effective strategies to maintain balance and adaptation to environmental challenges.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Consider a water-to-water counter-flow heat exchanger with these specifications. Hot water enters at \(95^{\circ} \mathrm{C}\) while cold water enters at \(20^{\circ} \mathrm{C}\). The exit temperature of hot water is \(15^{\circ} \mathrm{C}\) greater than that of cold water, and the mass flow rate of hot water is 50 percent greater than that of cold water. The product of heat transfer surface area and the overall heat transfer coefficient is \(1400 \mathrm{~W} / \mathrm{K}\). Taking the specific heat of both cold and hot water to be \(c_{p}=4180 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K}\), determine (a) the outlet temperature of the cold water, \((b)\) the effectiveness of the heat exchanger, \((c)\) the mass flow rate of the cold water, and \((d)\) the heat transfer rate.

A counter-flow heat exchanger is used to cool oil \(\left(c_{p}=\right.\) \(2.20 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K})\) from \(110^{\circ} \mathrm{C}\) to \(85^{\circ} \mathrm{C}\) at a rate of \(0.75 \mathrm{~kg} / \mathrm{s}\) by cold water \(\left(c_{p}=4.18 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}\right)\) that enters the heat exchanger at \(20^{\circ} \mathrm{C}\) at a rate of \(0.6 \mathrm{~kg} / \mathrm{s}\). If the overall heat transfer coefficient is \(800 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\), the heat transfer area of the heat exchanger is (a) \(0.745 \mathrm{~m}^{2}\) (b) \(0.760 \mathrm{~m}^{2}\) (c) \(0.775 \mathrm{~m}^{2}\) (d) \(0.790 \mathrm{~m}^{2}\) (e) \(0.805 \mathrm{~m}^{2}\)

Hot oil \(\left(c_{p}=2200 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K}\right)\) is to be cooled by water \(\left(c_{p}=4180 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K}\right)\) in a 2 -shell-passes and 12 -tube-passes heat exchanger. The tubes are thin-walled and are made of copper with a diameter of \(1.8 \mathrm{~cm}\). The length of each tube pass in the heat exchanger is \(3 \mathrm{~m}\), and the overall heat transfer coefficient is \(340 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). Water flows through the tubes at a total rate of \(0.1 \mathrm{~kg} / \mathrm{s}\), and the oil through the shell at a rate of \(0.2 \mathrm{~kg} / \mathrm{s}\). The water and the oil enter at temperatures \(18^{\circ} \mathrm{C}\) and \(160^{\circ} \mathrm{C}\), respectively. Determine the rate of heat transfer in the heat exchanger and the outlet temperatures of the water and the oil.

Consider a condenser unit (shell and tube heat exchanger) of an HVAC facility where saturated refrigerant \(\mathrm{R} 134 \mathrm{a}\) at a saturation pressure of \(1318.6 \mathrm{kPa}\) and a rate of \(2.5 \mathrm{~kg} / \mathrm{s}\) flows through thin-walled copper tubes. The refrigerant enters the condenser as saturated vapor and it is desired to have a saturated liquid refrigerant at the exit. The cooling of refrigerant is carried out by cold water that enters the heat exchanger at \(10^{\circ} \mathrm{C}\) and exits at \(40^{\circ} \mathrm{C}\). Assuming initial overall heat transfer coefficient of the heat exchanger to be \(3500 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\), determine the surface area of the heat exchanger and the mass flow rate of cooling water for complete condensation of the refrigerant. In practice, over a long period of time, fouling occurs inside the heat exchanger that reduces its overall heat transfer coefficient and causes the mass flow rate of cooling water to increase. Increase in the mass flow rate of cooling water will require additional pumping power making the heat exchange process uneconomical. To prevent the condenser unit from under performance, assume that fouling has occurred inside the heat exchanger and has reduced its overall heat transfer coefficient by \(20 \%\). For the same inlet temperature and flow rate of refrigerant, determine the new flow rate of cooling water to ensure complete condensation of the refrigerant at the heat exchanger exit.

Explain how the maximum possible heat transfer rate \(\dot{Q}_{\max }\) in a heat exchanger can be determined when the mass flow rates, specific heats, and the inlet temperatures of the two fluids are specified. Does the value of \(\dot{Q}_{\max }\) depend on the type of the heat exchanger?
See all solutions

Recommended explanations on Physics Textbooks

Classical Mechanics

Read Explanation

Force

Read Explanation

Medical Physics

Read Explanation

Waves Physics

Read Explanation

Quantum Physics

Read Explanation

Modern Physics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.