basal metabolic rate

Examples of basal metabolic rate in the following topics:

• Humans: Work, Energy, and Power

  • The rate at which the body uses food energy to sustain life and to do different activities is called the metabolic rate.
  • The total energy conversion rate of a person at rest is called the basal metabolic rate (BMR) and is divided among various systems in the body.
  • Identify what factors play a role in basal metabolic rate (BMR)

• Action of Thyroid Hormones

  • T4 is thought to be a pro-hormone to the more metabolically active T3.
  • The main activity of the thyroid hormones T3 and T4 is to boost the basal metabolic rates of proteins, fats, and carbohydrates as well as vitamins.
  • Thyroid hormones affect the dilation of blood vessels, which in turn affects the rate at which heat can escape the body.

• Human Metabolism

  • Your basal metabolic rate is the rate at which food is converted into heat transfer and work done while the body is at complete rest.
  • The body adjusts its basal metabolic rate to compensate (partially) for over-eating or under-eating.
  • The body will decrease the metabolic rate rather than eliminate its own fat to replace lost food intake.
  • You will become more easily chilled and feel less energetic as a result of the lower metabolic rate, and you will not lose weight as fast as before.
  • Exercise helps with weight loss because it produces both heat transfer from your body and work, and raises your metabolic rate even when you are at rest.

• Animal Bioenergetics

  • No energy system is one hundred percent efficient as an animal's metabolism produces waste energy in the form of heat.
  • The amount of energy expended by an animal over a specific time is called its metabolic rate.
  • The rate is measured in joules, calories, or kilocalories (1000 calories).
  • Metabolic rate is estimated as the basal metabolic rate (BMR) in endothermic animals at rest and as the standard metabolic rate (SMR) in ectotherms.
  • The mouse has a much higher metabolic rate than the elephant since it has greater surface area relative to mass.

• Aerobic Training vs. Strength Training

  • These fibers are suited for endurance activities and are slow to fatigue because they use oxidative metabolism to generate ATP.
  • The fast twitch fibers rely on a well-developed, short term, glycolytic system for energy transfer and can contract and develop tension at 2-3 times the rate of slow twitch fibers.
  • While Type II fibers are well suited for a superior rate of energy production, the duration over which this high level of energy production can be sustained is extremely finite.
  • The body's basal metabolic rate increases with increases in muscle mass, which may promote long-term fat loss and help individuals increase basal caloric expenditure.
  • Moreover, intense workouts elevate metabolism for several hours following the workout, which also promotes fat loss.

• Hormonal Regulation of Metabolism

  • Insulin lowers blood glucose levels by enhancing the rate of glucose uptake and utilization by target cells, which use glucose for ATP production.
  • The basal metabolic rate, which is the amount of calories required by the body at rest, is determined by two hormones produced by the thyroid gland: thyroxine, also known as tetraiodothyronine or T4, and triiodothyronine, also known as T3.
  • This results in increased rates of metabolism and body heat production.
  • Hypothyroidism, underproduction of the thyroid hormones, can cause a low metabolic rate leading to weight gain, sensitivity to cold, and reduced mental activity, among other symptoms.
  • Hyperthyroidism, the overproduction of thyroid hormones, can lead to an increased metabolic rate, which may cause weight loss, excess heat production, sweating, and an increased heart rate.

• Disorders of the Basal Ganglia

  • Basal ganglia disease refers to physical dysfunctions that occur when basal ganglia fail to suppress unwanted movements.
  • An example of a hypokinetic basal ganglia disease is Parkinsonism.
  • The basal ganglia is a collective group of structures in the brain .
  • Though there are known causes of dystonia such as metabolic, vascular, and structural abnormalities, there are still patients with dystonia with no apparent cause.
  • This is a diagram of the main circuits of the basal ganglia.

• The Limbic System

  • It helps the brain recognize potential threats and helps prepare the body for fight-or-flight reactions by increasing heart and breathing rate.
  • Lesions of the hypothalamus interfere with several unconscious functions (such as respiration and metabolism) and some so-called motivated behaviors like sexuality, combativeness, and hunger.
  • The basal ganglia is a group of nuclei lying deep in the subcortical white matter of the frontal lobes that organizes motor behavior.
  • The caudate, putamen, and globus pallidus are major components of the basal ganglia.
  • The basal ganglia is also involved with:

• Capillaries

  • They are surrounded by a thin basal lamina of connective tissue.
  • The more metabolically active the cells, the more capillaries required to supply nutrients and carry away waste products.
  • These types of blood vessels allow red and white blood cells (7.5μm - 25μm diameter) and various serum proteins to pass using a process aided by a discontinuous basal lamina.
  • When heart rate increases and more blood must flow through the lungs, capillaries are recruited and are distended to make room for increased blood flow while resistance decreases.
  • Capillaries are surrounded by a thin basal lamina of connective tissue.

• Metabolic Functions

  • One of the metabolic functions of the skin is the production of vitamin D3 when ultraviolet light reacts with 7-dehydrocholesterol.
  • The integumentary system distinguishes, separates, and protects the organism from its surroundings, but also plays a key metabolic function, as the major region for vitamin D production.
  • Vitamin D is produced in the two innermost strata of the epidermis, the stratum basale and stratum spinosum.