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Which Brain Region Contains The Cardiovascular Centers

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Neuronal Populations Of The Arc

A Tour of the Brain! | Self-Regulation Lesson 1

The ARC contains several populations of neurons that are defined by virtue of the transmitters or neuropeptides they express and their function. Neuroendocrine neurons of the ARC have long been the focus of neuroendocrinologists due to their proven influence on the anterior pituitary gland hormone secretion . These ARC neuroendocrine neurons include those expressing dopamine, which regulate secretion of prolactin and gonadotropin-releasing hormone, and those making growth hormoneâreleasing hormone that control the secretion of growth hormone. More recently, ARC neurons expressing kisspeptins have emerged as potent stimulators of the gonadotropic axis, with important implications in puberty onset and the control of gonadotropin secretion .

Apart from the neuroendocrine neurons regulating the pituitary gland, the ARC contains several neuronal populations involved in various physiological functions. The discovery of leptin in 1994 and subsequent identification of the ARC as one of its major targets brought this nucleus to the front stage of the neural control of energy homeostasis. The ARC was recognized as the site of âfirst orderâ neurons in the neural circuits regulating metabolism. The information about the nutritional status of the organism received by these neurons from various sources is conveyed to different regions of the central nervous system.

Coordinating Motor Survival Centres

The medulla contains the nuclei that control vital functions: the respiratory and cardiovascular centres, swallowing, blood pressure and vomiting . A key nucleus involved in these functions is the nucleus of the solitary tract . It is involved in the coordination of swallowing and breathing so that one does not swallow air or inhale food or vomit. The NTS also receives afferents from stretch receptors in the lungs and from CSF chemoreceptors on the surface of the medulla. These fibres project onto neurones situated in the respiratory centres located in the medullary RF. NTS also receives information from aortic baroreceptors located in the carotid body in the carotid artery and relays this information to the cardiovascular control centres to regulate blood pressure .

Paul Johns BSc BM MSc FRCPath, in, 2014

Abdominal Regions And Quadrants

Anatomists divide the abdominopelvic cavity into smaller regions to facilitate the study of body planes. This anatomical abdominal region division is used to recognize the location of the abdomen organs and to diagnose abdominal pain. The commonly abdominopelvic region is divided into four quadrants and nine regions.

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Connections Of The Hypothalamus

The hypothalamus is a small region of the brain connected with numerous, various cerebral structures that allows it to intervene in many regulatory processes of the organism. It has an important role in the optimal, normal functioning of the body, and it controls the endocrine system, the metabolism, and it is involved in stress control and in other different actions that modulates a persons behavior. More, the hypothalamus is involved in the homeostasis of the organism in terms of body temperature, blood pressure, fluid balance, and body weight.

The connections of the hypothalamus are made with the following structures.

Insulin Acts In The Arc To Increase Sympathetic Outflow

The Brain

Insulin action in the brain has been implicated in the regulation of various physiological processes. Pancreatic-derived insulin reaches the brain through a specific mechanism that involves active and saturable transport through the bloodâbrain barrier. Converging evidence from animal and human studies have shown that insulin is an important determinant of the activity of the sympathetic nervous system . Moreover and in line with the broad spectrum of physiological effects evoked by brain action of insulin, cerebroventricular administration of this hormone causes sympathetic nerve activation to numerous beds including the hindlimb, BAT, kidney, and adrenal gland . In addition, central action of insulin increases baroreflex control of both heart rate and lumbar SNA and causes a modest rise in arterial pressure .

The earlier finding that lesioning the anteroventral third ventricle eliminated the ability of insulin to induce sympathetic nerve activation implicated a key role for the hypothalamus in the sympathoexcitatory effects of this hormone . This was further substantiated by the elimination of insulin-induced sympathetic nerve activation after inhibition of insulin receptor signaling pathways in the hypothalamus and the capacity of insulin to increase SNA when administered into the lateral ventricle, but not the fourth ventricle .

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Ventricles And Cerebrospinal Fluid

Deep in the brain are four open areas with passageways between them. They also open into the central spinal canal and the area beneath arachnoid layer of the meninges.

The ventricles manufacture cerebrospinal fluid, or CSF, a watery fluid that circulates in and around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and brain, washes out waste and impurities, and delivers nutrients.

What Happens During Exercise

When you are exercising, you are using your muscles in a significant way, and your body demands that you take in more Oxygen so that it can be delivered to your muscles.

Your circulatory and respiratory systems need to make sure that the Oxygen is getting to the muscles faster than when you are just chilling. Also, they need to make sure that the carbon dioxide that is produced is taken away efficiently.

In order for that process to happen efficiently, the medulla oblongata, after sensing what is happening, sends signals to the heart and the respiratory muscles .

You start breathing heavily to get that Oxygen in and carbon dioxide out. Your heart starts beating faster because not only does the Oxygen need to get into the body, but they need to be delivered to the muscles.

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The Cell Structure Of The Brain

The brain is made up of two types of cells: neurons and glial cells, also known as neuroglia or glia. The neuron is responsible for sending and receiving nerve impulses or signals. Glial cells are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin and facilitate signal transmission in the nervous system. In the human brain, glial cells outnumber neurons by about 50 to one. Glial cells are the most common cells found in primary brain tumors.

When a person is diagnosed with a brain tumor, a biopsy may be done, in which tissue is removed from the tumor for identification purposes by a pathologist. Pathologists identify the type of cells that are present in this brain tissue, and brain tumors are named based on this association. The type of brain tumor and cells involved impact patient prognosis and treatment.

Brain Regions And Their Functions

Areas of the brain

Brain is the central part of the nervous system which governs the functions of various organs in the body. It is quite interesting to know what are the different regions of the brain and how these regions function. This article deals with the brain regions and their functions which will help you understand what part of your brain controls what mental activity.

Brain is the central part of the nervous system which governs the functions of various organs in the body. It is quite interesting to know what are the different regions of the brain and how these regions function. This article deals with the brain regions and their functions which will help you understand what part of your brain controls what mental activity.

The nervous system comprises of the brain, spinal cord and sensory nerves and it is the most complicated human body system. The Brain is the most complex and delicate organ of the human body. Though it weighs about 1.4 kg, it contains approximately a hundred billion nerve cells. It is made up of three major regions fore-brain, mid-brain and hind-brain and each region consists of different interdependent parts.

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Anatomical Terminology For Body Cavities

All vertebrates have fluid-filled spaces, which are called body cavities, and these cavities contain organs. The human also gave several body cavities, which are named anatomically according to the body organ and location where this cavity is found, such as a thoracic cavity, cranial cavity, and pelvic cavity.

These cavities also protect body organs. Here we will see the anatomical terms and anatomical planes of these body cavities.

Regulation Of Body Water Content

Water control in the living organism is assured by the hypothalamus through the antidiuretic hormone secretion. In cases of blood volume loss and dehydration, the ADH hormone is secreted from the supraoptic nucleusthat have osmoreceptor cellsand released in the circulation. The peptide is directed toward the specific receptor from kidneys and decreases the urine production with subsequent water retention in the organism.

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Divisions Of The Reticular Formation

Traditionally, the nuclei are divided into three columns:

  • Raphe nuclei
  • Magnocellular red nucleus
  • Parvocellular reticular nucleus
  • Sagittal division reveals more morphological distinctions. The raphe nuclei form a ridge in the middle of the reticular formation, and directly to its periphery, there is a division called the medial reticular formation. The medial reticular formation is large, has long ascending and descending fibers, and is surrounded by the lateral reticular formation. The lateral reticular formation is close to the motor nuclei of the cranial nerves and mostly mediates their function. The raphe nuclei is the place of synthesis of the neurotransmitter serotonin, which plays an important role in mood regulation.

    The medial reticular formation and lateral reticular formation are two columns of neuronal nuclei with ill-defined boundaries that send projections through the medulla and into the mesencephalon . The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves. The magnocellular red nucleus is involved in motor coordination, and the parvocellular nucleus regulates exhalation.

    Cross Section of the Pons: A cross section of the lower part of the pons showing the pontine reticular formation labeled as #9.

    Oculocardiac And Trigeminocardiac Reflexes

    What Is the Vasomotor Center? (with pictures)

    The oculocardiac reflex involves a decrease in heart rate and/or blood pressure in response to eyeball pressure. The reflex is thought to originate from the ophthalmic portion of the trigeminal nerve. Afferent stimuli move through the reticular formation and nuclei of the vagus nerve output and proceed via an efferent link through the vagus nerve to cardiovascular structures.

    The trigeminocardiac reflex is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, this could occur during craniofacial surgery, orbital fracture, balloon-compression rhizolysis of the trigeminal ganglion, and tumor resection in the cerebellopontine angle.

    The proposed mechanism for the development of TCR is the sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. The reaction subsides with cessation of the stimulus. Some patients may develop severe bradycardia, asystole, and hypotension, which require intervention.

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    Neurohormonal Adaptation In Heart Failure

    Sympathetic nervous system activation is a compensatory mechanism in heart failure with inotropic and chronotropic activity. Sympathetic activation is associated with pathologic ventricular remodeling, increased arrhythmias, sudden death, and increased mortality in chronic heart failure. Preliminary human studies suggest a positive effect of statins on sympathovagal balance in patients with heart failure.

    Where Is The Medulla Oblongata Located

    Your medulla oblongata looks like a rounded bulge at the end of your brain stem, or the part of your brain that connects with your spinal cord. It also lies in front of the part of your brain called the cerebellum.

    Your cerebellum looks like a tiny brain joined onto the back of your brain. In fact, its name literally translates to little brain from Latin.

    The hole in your skull that lets your spinal cord pass through is called your foramen magnum. Your medulla oblongata is located at about the same level or slightly above this hole.

    The top of your medulla creates the floor of the fourth ventricle of your brain. Ventricles are cavities filled with cerebral spinal fluid that help provide your brain with nutrients.

    cranial nerves originate on this region.

    Your brain and spine communicate through columns of nerve fibers that run through your medulla called spinal tracts. These tracts can be ascending or descending .

    Each of your spinal tracts carries a specific type of information. For example, your lateral spinothalamic tract carries information related to pain and temperature.

    If part of your medulla becomes damaged, it can lead to an inability to relay a specific type of message between your body and brain. The types of information carried by these spinal tracts include:

    • pain and sensation

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    Regulation Of Food Intake

    The hypothalamus controls appetite and food intake through the ventromedial, dorsomedial, paraventricular, and lateral hypothalamus nucleus. The ventromedial nucleus is referred to as the appetite-suppressing or anorexigenic center. Destruction of this nucleus leads to hyperpolyphagia, obesity, and to an aggressive behavior.

    Contrary, the appetite-increasing or orexigenic center is considered to be the lateral hypothalamic nucleus that can lead to aphagia and cashexy in case of its destruction and to hyperphagia or polyphagia in case of its stimulation.

    Appetite control is modulated by the leptin hormone released by the fatty cells that binds to specific hypothalamic receptors.

    Cardiovascular Regulation By The Arcuate Nucleus Of The Hypothalamus: Neurocircuitry And Signaling Systems

    How Exactly Is the Human Brain Organized?

    1Department of Pharmacology, University of Iowa, Iowa City, Iowa

    2Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa

    Address correspondence to:

    The importance of the central nervous system in cardiovascular regulation is well established . The brain is able to sense changes that occur in the peripheral circulation through several mechanisms including afferent neural reflexes and humoral signals. The brain in turn can adjust various components of the cardiovascular system to maintain homeostasis by modulating the release of critical hormonal factors, chemical messengers, and neurotransmitters in concert with changing the activity of the sympathetic and parasympathetic branches of the autonomic nervous system subserving different organs and tissues throughout the body.

    The arcuate nucleus of the hypothalamus is emerging as a major player in cardiovascular and sympathetic regulation . I will review the neuroanatomical and cellular characteristics of the ARC before discussing the evidence that implicates the ARC in the control of blood pressure and sympathetic outflow.

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    Control Of The Autonomic Nervous System By Higher Brain Centers

    Visceral functions are largely regulated by autonomic reflexes. In most autonomic reflexes, sensory input is transmitted to brain centers that integrate this information and respond by modifying the activity of preganglionicautonomic neurons. The neural centers that directly control the activity of autonomic nerves are influenced by higher brain areas, as well as by sensory input.

    The medulla oblongata of the brain stem is the area that most directly controls the activity of the autonomic system. Almost all autonomic responses can be elicited by experimental stimulation of the medulla, where centers for the control of the cardiovascular, pulmonary, urinary, reproductive, and digestive systems are located. Much of the sensory input to these centers travels in the afferent fibers of the vagus nervea mixed nerve containing both sensory and motor fibers. The reflexes that result are listed in table 9.8.

    Although it directly regulates the activity of autonomic motor fibers, the medulla itself is responsive to regulation by higher brain areas. One of these areas is the hypothalamus, the brain region that contains centers for the control of body temperature, hunger, and thirst for regulation of the pituitary gland and for various emotional states.

    Test Yourself Before You Continue

    1. Define adrenergic and cholinergic and use these terms to describe the neurotransmitters of different autonomic nerve fibers.

    Eighth Edition System Companies, 2003

    Skeletal System

    Autonomic Innervation Of The Heart And Vasculature

    The medulla, located in the brainstem above the spinal cord, is a major site in the brain for regulating autonomic nerve outflow to the heart and blood vessels, and is particularly important for short-term feedback regulation of arterial pressure. The medulla contains cell bodies for the two main divisions of the autonomic nervous system – sympathetic and parasympathetic. The sympathetic nerves exit the medulla and travel down the spinal cord where they synapse with relatively short preganglionic fibers that travel to, and synapse within, sympathetic ganglia. Postganglionic efferent fibers from the ganglia travel to the heart and vasculature where they synapse at their target sites. The parasympathetic nerves exit the medulla as long preganglionic efferent fibers that form synapses with short postganglionic fibers within the heart or vascular tissue. The activity of the medullary neurons is modulated by input from peripheral sensors and from other brain regions.

    The heart is innervated by vagal and sympathetic fibers. The right vagus nerve primarily innervates the SA node, whereas the left vagus innervates the AV node however, there can be significant overlap in the anatomical distribution. Atrial muscle is also innervated by vagal efferents, whereas the ventricular myocardium is only sparsely innervated by vagal efferents. Sympathetic efferent nerves are present throughout the atria and ventricles, including the conduction system of the heart.

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    Lobes Of The Brain And What They Control

    Each brain hemisphere has four sections, called lobes: frontal, parietal, temporal and occipital. Each lobe controls specific functions.

    • Frontal lobe. The largest lobe of the brain, located in the front of the head, the frontal lobe is involved in personality characteristics, decision-making and movement. Recognition of smell usually involves parts of the frontal lobe. The frontal lobe contains Brocas area, which is associated with speech ability.
    • Parietal lobe. The middle part of the brain, the parietal lobe helps a person identify objects and understand spatial relationships . The parietal lobe is also involved in interpreting pain and touch in the body. The parietal lobe houses Wernickes area, which helps the brain understand spoken language.
    • Occipital lobe. The occipital lobe is the back part of the brain that is involved with vision.
    • Temporal lobe. The sides of the brain, temporal lobes are involved in short-term memory, speech, musical rhythm and some degree of smell recognition.

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