DOCSLIB.ORG

49 the Autonomic Nervous System and the Hypothalamus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
49 the Autonomic Nervous System and the Hypothalamus Back 49 The Autonomic Nervous System and the Hypothalamus Susan Iversen Leslie Iversen Clifford B. Saper WHEN WE ARE FRIGHTENED our heart races, our breathing becomes rapid and shallow, our mouth becomes dry, our muscles tense, our palms become sweaty, and we may want to run. These bodily changes are mediated by the autonomic nervous system, which controls heart muscle, smooth muscle, and exocrine glands. The autonomic nervous system is distinct from the somatic nervous system, which controls skeletal muscle. As we shall learn in the next chapter, even though the neural control of emotion involves several regions, including the amygdala and the limbic association areas of the cerebral cortex, they all work through the hypothalamus to control the autonomic nervous system. The hypothalamus coordinates behavioral response to insure bodily homeostasis, the constancy of the internal environment. The hypothalamus, in turn, acts on three major systems: the autonomic nervous system, the endocrine system, and an ill-defined neural system concerned with motivation. In this chapter we shall first examine the autonomic nervous system and then go on to consider the hypothalamus. In the next two chapters, we shall examine emotion and motivation, behavioral states that depend greatly on autonomic and hypothalamic mechanisms. P.961 The Autonomic Nervous System Is a Visceral and Largely Involuntary Sensory and Motor System In contrast to the somatic sensory and motor systems, which we considered in Parts IV and V of this book, the autonomic nervous system is a visceral sensory and motor system. Virtually all visceral reflexes are mediated by local circuits in the brain stem or spinal cord. Although these reflexes are regulated by a network of central autonomic control nuclei in the brain stem, hypothalamus, and forebrain, these visceral reflexes are not under voluntary control, nor do they impinge on consciousness, with few exceptions. The autonomic nervous system is thus also referred to as the involuntary motor system, in contrast to the voluntary (somatic) motor system. The autonomic nervous system has three major divisions: sympathetic, parasympathetic, and enteric. The sympathetic and parasympathetic divisions innervate cardiac muscle, smooth muscle, and glandular tissues and mediate a variety of visceral reflexes. These two divisions include the sensory neurons associated with spinal and cranial nerves, the preganglionic and postganglionic motor neurons, and the central nervous system circuitry that connects with and modulates the sensory and motor neurons. The enteric division has greater autonomy than the other two divisions and comprises a largely self-contained system, with only minimal connections to the rest of the nervous system. It consists of sensory and motor neurons in the gastrointestinal tract that mediate digestive reflexes. The American physiologist Walter B. Cannon first proposed that the sympathetic and parasympathetic divisions have distinctly different functions. He argued that the parasympathetic nervous system is responsible for rest and digest, maintaining basal heart rate, respiration, and metabolism under normal conditions. The sympathetic nervous system, on the other hand, governs the emergency reaction, or fight-or-flight reaction. In an emergency the body needs to respond to sudden changes in the external or internal environment, be it emotional stress, combat, athletic competition, severe change in temperature, or blood loss. For a person to respond effectively, the sympathetic nervous system increases output to the heart and other viscera, the peripheral vasculature and sweat glands, and the piloerector and certain ocular muscles. An animal whose sympathetic nervous system has been experimentally eliminated can only survive if sheltered, kept warm, and not exposed to stress or emotional stimuli. Such an animal cannot, however, carry out strenuous work or fend for itself; it cannot mobilize blood sugar from the liver quickly and does not react to cold with normal vasoconstriction or elevation of body heat. Figure 49-1 Anatomical organization of the somatic and autonomic motor pathways. A. In the somatic motor system, effector motor neurons in the central nervous system project directly to skeletal muscles. B. In the autonomic motor system, the effector motor neurons are located in ganglia outside the central nervous system and are controlled by preganglionic central neurons. The relationship between the sympathetic and parasympathetic pathways is not as simple and as independent as suggested by Cannon, however. Both divisions are tonically active and operate in conjunction with each other and with the somatic motor system to regulate most behavior, be it normal or emergency. Although several visceral functions are controlled predominantly by one or the other division, and although both the sympathetic and parasympathetic divisions often exert opposing effects on innervated target tissues, it is the balance of activity between the two that helps maintain an internal stable environment in the face of changing external conditions. The idea of a stable internal environment in the face of changing external conditions was first proposed in the nineteenth century by the French physiologist Claude Bernard. This idea was developed further by Cannon, who put forward the concept of homeostasis as the complex P.962 physiological mechanisms that maintain the internal milieu. In his classic book The Wisdom of the Body published in 1932, Cannon introduced the concept of negative feedback regulation as a key homeostatic mechanism and outlined much of our current understanding of the functions of the autonomic nervous system. Figure 49-2 Anatomical organization of the sympathetic preganglionic and postganglionic axons. (Adapted from Loewy and Spyer 1990.) If a state remains steady, it does so because any change is automatically met by increased effectiveness of the factor or factors that resist the change. Consider, for example, thirst when the body lacks water; the discharge of adrenaline, which liberates sugar from the liver when the concentration of sugar in the blood falls below a critical point; and increased breathing, which reduces carbonic acid when the blood tends to shift toward acidity. Cannon further proposed that the autonomic nervous system, under the control of the hypothalamus, is an important part of this feedback regulation. The hypothalamus regulates many of the neural circuits that mediate the peripheral components of emotional states: changes in heart rate, blood pressure, temperature, and water and food intake. It also controls the pituitary gland and thereby regulates the endocrine system. Each of the Three Divisions of the Autonomic Nervous System Has a Distinctive Anatomical Organization The Motor Neurons of the Autonomic Nervous System Lie Outside the Central Nervous System In the somatic motor system the motor neurons are part of the central nervous system: They are located in the spinal cord and brain stem and project directly to skeletal muscle. In contrast, the motor neurons of the sympathetic and parasympathetic motor systems are located outside the spinal cord in the autonomic ganglia. The autonomic motor neurons (also known as postganglionic neurons) are activated by the axons of central neurons (the preganglionic neurons) whose cell bodies are located in the spinal cord or brain stem, much as are the somatic motor neurons. Thus, in the visceral motor system a synapse (in the autonomic ganglion) is interposed between the efferent neuron in the central nervous system and the peripheral target (Figure 49-1). The sympathetic and parasympathetic nervous systems have clearly defined sensory components that provide input to the central nervous system and play an important role in autonomic reflexes. In addition, some sensory fibers that project to the spinal cord also send a branch to autonomic ganglia, thus forming reflex circuits that control some visceral autonomic functions. The innervation of target tissues by autonomic nerves also differs markedly from that of skeletal muscle by somatic motor nerves. Unlike skeletal muscle, which has specialized postsynaptic regions (the end-plates; see Chapter 14), target cells of the autonomic nerve fibers have no specialized postsynaptic sites. Nor do the postganglionic nerve endings have presynaptic specializations such as the active zones of somatic motor neurons. Instead, the nerve endings have several swellings (varicosities) where vesicles containing transmitter substances accumulate (see Chapter 15). Synaptic transmission therefore occurs at multiple sites along the highly branched axon terminals of autonomic nerves. The neurotransmitter may diffuse for distances P.963 as great as several hundred nanometers to reach its targets. In contrast to the point-to-point contacts made in the somatic motor system, neurons in the autonomic motor system exert a more diffuse control over target tissues, so that a relatively small number of highly branched motor fibers can regulate the function of large masses of smooth muscle or glandular tissue. Sympathetic Pathways Convey Thoracolumbar Outputs to Ganglia Alongside the Spinal Cord Preganglionic sympathetic neurons form a column in the intermediolateral horn of the spinal cord extending from the first thoracic spinal segment to rostral lumbar segments. The axons of these neurons leave the spinal cord in the ventral root and initially run together in the spinal nerve. They then separate from the somatic motor
Load more

Recommended publications
  • The Baseline Structure of the Enteric Nervous System and Its Role in Parkinson’S Disease
    life Review The Baseline Structure of the Enteric Nervous System and Its Role in Parkinson’s Disease Gianfranco Natale 1,2,* , Larisa Ryskalin 1 , Gabriele Morucci 1 , Gloria Lazzeri 1, Alessandro Frati 3,4 and Francesco Fornai 1,4 1 Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy; [email protected] (L.R.); [email protected] (G.M.); [email protected] (G.L.); [email protected] (F.F.) 2 Museum of Human Anatomy “Filippo Civinini”, University of Pisa, 56126 Pisa, Italy 3 Neurosurgery Division, Human Neurosciences Department, Sapienza University of Rome, 00135 Rome, Italy; [email protected] 4 Istituto di Ricovero e Cura a Carattere Scientifico (I.R.C.C.S.) Neuromed, 86077 Pozzilli, Italy * Correspondence: [email protected] Abstract: The gastrointestinal (GI) tract is provided with a peculiar nervous network, known as the enteric nervous system (ENS), which is dedicated to the fine control of digestive functions. This forms a complex network, which includes several types of neurons, as well as glial cells. Despite extensive studies, a comprehensive classification of these neurons is still lacking. The complexity of ENS is magnified by a multiple control of the central nervous system, and bidirectional communication between various central nervous areas and the gut occurs. This lends substance to the complexity of the microbiota–gut–brain axis, which represents the network governing homeostasis through nervous, endocrine, immune, and metabolic pathways. The present manuscript is dedicated to Citation: Natale, G.; Ryskalin, L.; identifying various neuronal cytotypes belonging to ENS in baseline conditions.
    [Show full text]
  • Autonomic Nerve Activity and Cardiac Arrhythmias
    ACORP Complete (with appendices) Last Name of PI► Protocol No. Assigned by the IACUC►02002 Official Date of Approval► 1. Caging needs. Complete the table below to describe the housing that will have to be accommodated by the housing sites for this protocol: d. Is this housing e. Estimated c. Number of consistent with the maximum number a. Species b. Type of housing* individuals per Guide and USDA of housing units housing unit** regulations? needed at any one (yes/no***) time Chain link run, 3x6 Canines 1 no 7 and 4x10 feet cage *See ACORP Instructions, for guidance on describing the type of housing needed. If animals are to be housed according to a local Standard Operating Procedure (SOP), enter “standard (see SOP)” here, and enter the SOP into the table in Item Y. If the local standard housing is not described in a SOP, enter “standard, see below” in the table and describe the standard housing here: Chain link run, 3x6 feet cages ** The Guide states that social animals should generally be housed in stable pairs or groups. Provide a justification if any animals will be housed singly (if species is not considered “social”, then so note) Dogs are housed singly in chain link runs but can socialize with one another since each room has two to five dog runs. In addition, while their runs are being cleaned on a daily basis, pairs of dogs are allowed to exercise and play together in a designated "romper room". Animals are fitted with DSI transmitters and need to be housed singly in a cage for which DSI receivers are installed to receive signals from the transmitters.
    [Show full text]
  • 1-Anatomy of the Pituitary Gland
    Color Code Important Anatomy of Pituitary Gland Doctors Notes Notes/Extra explanation Please view our Editing File before studying this lecture to check for any changes. Objectives At the end of the lecture, students should be able to: ✓ Describe the position of the pituitary gland. ✓ List the structures related to the pituitary gland. ✓ Differentiate between the lobes of the gland. ✓ Describe the blood supply of pituitary gland & the hypophyseal portal system. الغدة النخامية Pituitary Gland (also called Hypophysis Cerebri) o It is referred to as the master of endocrine glands. o It is a small oval structure 1 cm in diameter. o It doubles its size during pregnancy. lactation ,(الحمل) pregnancy ,(الحيض) A women experiences changes in her hormone levels during menstruation But only the pituitary gland will only increase in size during pregnancy .(سن اليأس) and menopause ,(الرضاعة) X-RAY SKULL: LATERAL VIEW SAGITTAL SECTION OF HEAD & NECK Extra Pituitary Gland Position o It lies in the middle cranial fossa. o It is well protected in sella turcica* (hypophyseal fossa) of body of sphenoid o It lies between optic chiasma (anteriorly) & mamillary bodies** (posteriorly). Clinical point: *سرج الحصان Anterior to the pituitary gland is the optic chiasm, so if there was a tumor in the pituitary gland or it was ** Part of hypothalamus enlarged this could press on the chiasm and disrupt the patients vision (loss of temporal field). Extra Pictures The purple part is the sphenoid bone Hypophyseal fossa Pituitary Gland The relations are important Important Relations • SUPERIOR: Diaphragma sellae: A fold of dura mater covers the pituitary gland & has an opening for passage of infundibulum (pituitary stalk) connecting the gland to hypothalamus.
    [Show full text]
  • Glossary of Pediatric Endocrine Terms
    Glossary of Pediatric Endocrine Terms Adrenal Glands: Triangle-shaped glands located on top of each kidney that are responsible for the regulation of stress response by producing hormones such as cortisol and adrenaline. Adrenal Crisis: A life-threatening condition that results when there is not enough cortisol (stress hormone) in the body. This may present with nausea, vomiting, abdominal pain, severely low blood pressure, and loss of consciousness. Adrenocorticotropin (ACTH): A hormone produced by the anterior pituitary gland that triggers the adrenal gland to produce cortisol, the stress hormone. Anterior Pituitary: The front of the pituitary gland that secretes growth hormone, gonadotropins, thyroid stimulating hormone, prolactin, adrenocorticotropin hormone. Antidiuretic Hormone: A hormone secreted by the posterior pituitary that controls how much water is excreted by the kidneys (water balance). Bone Age Study: An X-ray of the left hand and wrist to assess a child’s skeletal age. It is often used to evaluate disorders of puberty and growth. Congenital Adrenal Hyperplasia: A group of disorders which impair the adrenal steroid synthesis pathway. This causes the body makes too many androgens. Sometimes the body does not make enough cortisol and aldosterone. Constitutional Delay of Growth and Puberty: A normal variant of growth in which children grow at a slower rate and begin puberty later than their peers. They may appear short until they have catch up growth. They usually end up at a normal adult height. A diagnosis of constitutional delay of growth and puberty is often referred to as being a “late bloomer.” Cortisol: The “stress hormone”, which is produced by the adrenal glands.
    [Show full text]
  • Hypothalamus and Pituitary Gland Development in the Common Snapping Turtle, Chelydra Serpentina, and Disruption with Atrazine Exposure
    University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects January 2016 Hypothalamus And Pituitary Gland Development In The ommonC Snapping Turtle, Chelydra Serpentina, And Disruption With Atrazine Exposure Kathryn Lee Gruchalla Russart Follow this and additional works at: https://commons.und.edu/theses Recommended Citation Russart, Kathryn Lee Gruchalla, "Hypothalamus And Pituitary Gland Development In The ommonC Snapping Turtle, Chelydra Serpentina, And Disruption With Atrazine Exposure" (2016). Theses and Dissertations. 2069. https://commons.und.edu/theses/2069 This Dissertation is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. HYPOTHALAMUS AND PITUITARY GLAND DEVELOPMENT IN THE COMMON SNAPPING TURTLE, CHELYDRA SERPENTINA, AND DISRUPTION WITH ATRAZINE EXPOSURE by Kathryn Lee Gruchalla Russart Bachelor of Science, Minnesota State University, Mankato, 2006 A Dissertation Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Doctor of Philosophy Grand Forks, North Dakota August 2016 Copyright 2016 Kathryn Russart ii iii PERMISSION Title Hypothalamus and Pituitary Gland Development in the Common Snapping Turtle, Chelydra serpentina, and Disruption with Atrazine Exposure Department Biology Degree Doctor of Philosophy In presenting this dissertation in partial fulfillment of the requirements for a graduate degree from the University of North Dakota, I agree that the library of this University shall make it freely available for inspection.
    [Show full text]
  • What Is the Autonomic Nervous System?
    J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.74.suppl_3.iii31 on 21 August 2003. Downloaded from AUTONOMIC DISEASES: CLINICAL FEATURES AND LABORATORY EVALUATION *iii31 Christopher J Mathias J Neurol Neurosurg Psychiatry 2003;74(Suppl III):iii31–iii41 he autonomic nervous system has a craniosacral parasympathetic and a thoracolumbar sym- pathetic pathway (fig 1) and supplies every organ in the body. It influences localised organ Tfunction and also integrated processes that control vital functions such as arterial blood pres- sure and body temperature. There are specific neurotransmitters in each system that influence ganglionic and post-ganglionic function (fig 2). The symptoms and signs of autonomic disease cover a wide spectrum (table 1) that vary depending upon the aetiology (tables 2 and 3). In some they are localised (table 4). Autonomic dis- ease can result in underactivity or overactivity. Sympathetic adrenergic failure causes orthostatic (postural) hypotension and in the male ejaculatory failure, while sympathetic cholinergic failure results in anhidrosis; parasympathetic failure causes dilated pupils, a fixed heart rate, a sluggish urinary bladder, an atonic large bowel and, in the male, erectile failure. With autonomic hyperac- tivity, the reverse occurs. In some disorders, particularly in neurally mediated syncope, there may be a combination of effects, with bradycardia caused by parasympathetic activity and hypotension resulting from withdrawal of sympathetic activity. The history is of particular importance in the consideration and recognition of autonomic disease, and in separating dysfunction that may result from non-autonomic disorders. CLINICAL FEATURES c copyright. General aspects Autonomic disease may present at any age group; at birth in familial dysautonomia (Riley-Day syndrome), in teenage years in vasovagal syncope, and between the ages of 30–50 years in familial amyloid polyneuropathy (FAP).
    [Show full text]
  • Brainstem Dysfunction in Critically Ill Patients
    Benghanem et al. Critical Care (2020) 24:5 https://doi.org/10.1186/s13054-019-2718-9 REVIEW Open Access Brainstem dysfunction in critically ill patients Sarah Benghanem1,2 , Aurélien Mazeraud3,4, Eric Azabou5, Vibol Chhor6, Cassia Righy Shinotsuka7,8, Jan Claassen9, Benjamin Rohaut1,9,10† and Tarek Sharshar3,4*† Abstract The brainstem conveys sensory and motor inputs between the spinal cord and the brain, and contains nuclei of the cranial nerves. It controls the sleep-wake cycle and vital functions via the ascending reticular activating system and the autonomic nuclei, respectively. Brainstem dysfunction may lead to sensory and motor deficits, cranial nerve palsies, impairment of consciousness, dysautonomia, and respiratory failure. The brainstem is prone to various primary and secondary insults, resulting in acute or chronic dysfunction. Of particular importance for characterizing brainstem dysfunction and identifying the underlying etiology are a detailed clinical examination, MRI, neurophysiologic tests such as brainstem auditory evoked potentials, and an analysis of the cerebrospinal fluid. Detection of brainstem dysfunction is challenging but of utmost importance in comatose and deeply sedated patients both to guide therapy and to support outcome prediction. In the present review, we summarize the neuroanatomy, clinical syndromes, and diagnostic techniques of critical illness-associated brainstem dysfunction for the critical care setting. Keywords: Brainstem dysfunction, Brain injured patients, Intensive care unit, Sedation, Brainstem
    [Show full text]
  • The Autonomic Nervous System and Gastrointestinal Tract Disorders
    NEUROMODULATION THE AUTONOMIC NERVOUS SYSTEM AND GASTROINTESTINALTRACT DISORDERS TERRY L. POWLEY, PH.D. PURDUE UNIVERSITY • MULTIPLE REFRACTORY GI DISORDERS EXIST. • VISCERAL ATLASES OF THE GI TRACT ARE AVAILABLE. • REMEDIATION WITH ELECTROMODULATION MAY BE PRACTICAL. TERRY l. POWLEY, PH.D. PURDUE NEUROMODUlATION: THE AUTONOMIC NERVOUS SYSTEM AND GASTP.OINTESTINAL TRACT DISORDERS UNIVERSITY 50 INTERNATIONAL I:"' NEUROMODULATION SOCIETY 0 40 ·­IS 12TH WORLD CONGRESS -I: -• 30 !"' A. -..0 20 ..a• E 10 z::::t TERRY l. POWLEY, PH.D. PURDUE NEUROMODUlATION: THE AUTONOMIC NERVOUS SYSTEM AND GASTP.OINTESTINAL TRACT DISORDERS UNIVERSITY DISORDERS TO TREAT WITH NEUROMODULATION ACHALASIA DYSPHAGIA GASTROPARESIS GERD GUT DYSMOTILITY MEGA ESOPHAGUS DYSPEPSIA ,, VISCERAL PAIN l1 ' I NAUSEA, EMESIS OBESITY ,, ' 11 I PYLORIC STENOSIS ==..:.= --- "" .:.= --- .. _ _, DUMPING REFLUX COLITIS I:' . - IBS -·-- - CROHN'S DISEASE HIRSCHSPRUNG DISEASE CHAGAS DISUSE Gastrointestinal Tract Awodesk@ Ma;·a@ TERRY l. POWLEY, PH.D. PURDUE NEUROMODUlATION: THE AUTONOMIC NERVOUS SYSTEM AND GASTP.OINTESTINAL TRACT DISORDERS UNIVERSITY TIME The Obesity Epidemic in America ·. TERRY l. POWLEY, PH.D. PURDUE NEU ROMODUlATION : THE AUTO N OMIC NERVOUS SYSTEM A N D G A STP.OINTESTINAL TRACT DISORDERS UNI V E R SI TY ROUX-EN-Y BYPASS Bypassed portion of stomach Gastric -"'~­ pouch Bypassed - ­ Jejunum duodenum -1" food -___----_,,.,. digestivejuice TERRY l. POWLEY, PH.D. PURDUE NEU ROMODUlATION: THE AUTONOMIC NERVOUS SYSTEM A N D GASTP.OINTESTINAL TRACT DISORDERS UNIVERSITY 8y~s~ portionof i t()(l\3Ch • TERRYl. POWLEY, PH.D. PURDUE NEUROMOOUlATION: THE AUTONOMIC NERVOUS SYSTEM ANO 0.-STP.OINTESTINAL TRACT DISORDERS UHIVlflSITY • DESPERATE PATIENTS • ABSENCE OF SATISFACTORY PHARMACOLOGICAL TREATMENTS • POPULAR MEDIA HYPE • ABSENCE OF A SOLID MECHANISTIC UNDERSTANDING • UNCRITICAL ACCEPTANCE OF PROPONENT'S CLAIMS • MYOPIA REGARDING SIDE EFFECTS TERRY l.
    [Show full text]
  • Dear Subscribers! This Issue of Our Magazine Is Devoted to Cooperation of Our Editorial Board with Ukrainian Medical Scientists
    Deutscher Wissenschaftsherold • German Science Herald, N 4/2016 Dear subscribers! This issue of our magazine is devoted to cooperation of our editorial board with Ukrainian medical scientists. We present you the results of their researches. UDC: 611.831.1:611.216-018.73 Boichuk O.M. Higher State Educational Institution of Ukraine “Bukovinian State Medical University”, M.H. Turkevych Department of Human Anatomy, Chernivtsi, Ukraine, [email protected] Kryvetska I.I. Higher State Educational Institution of Ukraine “Bukovinian State Medical University”, S.M. Savenko Department of Neurology, Psychiatry and Medical Psychology Chernivtsi, Ukraine Bambuliak A.V. Higher State Educational Institution of Ukraine “Bukovinian State Medical University”, Department of Surgical and Pediatric Dentistry, Chernivtsi, Ukraine, [email protected] Sapunkov O.D. Higher State Educational Institution of Ukraine “Bukovinian State Medical University”, Department of Pediatric Surgery and Otolaryngology, Chernivtsi, Ukraine STRUCTURAL COMPONENTS OF AUTONOMIC INNERVATION OF MUCOSA OF NASAL CAVITY AND PARANASAL SINUSES Abstract. Autonomic innervation of mucosa of the nasal cavity and paranasal sinuses has been studied using complex morphological methods. It was determined that autonomic innervation of the nasal cavity and paranasal sinuses mostly occurs due to the branches of the pterygopalatine ganglion Keywords: nasal cavity, paranasal sinuses, innervation, pterygopalatine ganglion, mucosa, anatomy. Introduction. Mucosa of nasal cavity is peripheral element of olfactory analyzer functionally large receptor surface with a very consists of highly specialized epithelium of the complex and various reflex connections. It is upper nasal passage, short dendrites, which equipped with lots of blood and lymphatic ends with receptors, and axons form olfactory vessels, which are surrounded with numerous filaments that enter the olfactory bulb where nerve endings.
    [Show full text]
  • Pituitary Disease Handbook for Patients Disclaimer This Is General Information Developed by the Ottawa Hospital
    The Ottawa Hospital Divisions of Endocrinology and Metabolism and Neurosurgery Pituitary Disease Handbook for Patients Disclaimer This is general information developed by The Ottawa Hospital. It is not intended to replace the advice of a qualified health-care provider. Please consult your health-care provider who will be able to determine the appropriateness of the information for your specific situation. Prepared by Monika Pantalone, NP Advanced Practice Nurse for Neurosurgery With guidance from Dr. Charles Agbi, Dr. Erin Keely, Dr. Janine Malcolm and The Ottawa Hospital pituitary patient advisors P1166 (10/2014) Printed at The Ottawa Hospital Outline This handbook is designed to help people who have pituitary tumours better understand their disease. It contains information to help people with pituitary tumours discuss their care with health care providers. This booklet provides: 1) An overview of what pituitary tumours are and how they are grouped 2) An explanation of how pituitary tumours are investigated 3) A description of available treatments for pituitary tumours What is the Pituitary Gland? The pituitary gland is a pea size organ located just behind the bridge of the nose at the base of the brain, in a bony pouch called the “sella turcica.” It sits just below the nerves to the eyes (the optic chiasm). The pituitary gland is divided into two main portions: the larger anterior pituitary (at the front) and the smaller posterior pituitary (at the back). Each of these portions has different functions, producing different types of hormones. Optic Pituitary Hypothalamus tumor chiasm Pituitary stalk Anterior Sphenoid pituitary gland sinus Posterior pituitary gland Sella Picture provided by turcica pituitary.ucla.edu 1 The pituitary gland is known as the “master gland” because it helps to control the secretion of various hormones from a number of other glands including the thyroid gland, adrenal glands, testes and ovaries.
    [Show full text]
  • Biology 251 Fall 2015 1 TOPIC 6: CENTRAL NERVOUS SYSTEM I
    Biology 251 Fall 2015 TOPIC 6: CENTRAL NERVOUS SYSTEM I. Introduction to the Nervous System A. Objective: We’ve discussed mechanisms of how electrical signals are transmitted within a neuron (Topic 4), and how they are transmitted from neuron to neuron (Topic 5). For the next 3 Topics, we will discuss how neurons are organized into functioning units that allow you to think, walk, smell, feel pain, etc. B. Organization of nervous system. Note that this is a subdivision of a single integrated system, based on differences in structure, function and location (Fig 7.1). Such a subdivision allows easier analysis and understanding than trying to comprehend the system as a whole. 1. Central Nervous System (integrates and issues information) a) brain b) spinal cord 2. Peripheral Nervous System a) Afferent Division (sends information to CNS) b) Efferent Division (receives information from CNS) (1) Somatic nervous system (2) Autonomic nervous system (a) Sympathetic nervous system (b) Parasympathetic nervous system C. Three classes of neurons (Fig 7.4) 1. afferent neurons a) have sensory receptors b) axon terminals in CNS c) send information to CNS from body 2. efferent neurons a) cell body in CNS b) axon terminals in effector organ c) send information from CNS to body 3. interneurons a) lie within CNS b) some connect afferent neurons and efferent neurons (1) integrate peripheral responses and peripheral information c) some connect other interneurons (1) responsible for activity of the “mind”, i.e., thoughts, emotions, motivation, etc. d) 99% of all neurons are interneurons II. The Brain: Gross Structure and Associated Functions (Fig 9.11) A.
    [Show full text]
  • Autonomic Nervous System
    Editing file Lecture 4: AUTONOMIC NERVOUS SYSTEM • Red : important • Pink : in girls slides only • Blue : in male slides only • Green : notes, Extra Objectives At the end of the lecture, students should be able to: ❖ Define the autonomic nervous system. ❖ Describe the structure of autonomic nervous system ❖ Trace the preganglionic & postganglionic neurons in both sympathetic & parasympathetic nervous system. ❖ Enumerate in brief the main effects of sympathetic & parasympathetic system Autonomic Nervous System The autonomic nervous system is concerned with the Autonomic nervous system: Nerve cells innervation and control of Involuntary structures such as located in both central & visceral organs, smooth muscles, cardiac muscles and glands. peripheral nervous system Skeletal muscles are controlled by somatic motor Difference between somatic and visceral motor: ● Somatic motor ● Function: Maintaining the homeostasis Fibers from Anterior horn cell —-> to target of the internal environment along with ● Visceral motor Regulation: (Controlled) the endocrine system. 1-Brain: from nuclei by the Hypothalamus 2- spinal cord: lateral horn cell Note: Hypothalamus controls ﺗﻌدي ﻋﻠﻰ . Ganglion ﻗﺑل ﺗوﺻل ﻟﻠـ Location: Central nervous system and Target ● both of Autonomic system + peripheral nervous system Endocrine system. Autonomic Nervous System Unlike the somatic nervous system, the Efferent pathway of the autonomic nervous system is made up of Preganglionic Neuron two neurons called as: Preganglionic Postganglionic The cell bodies are The cell bodies are Postganglionic Neuron located in the brain located in the and spinal cord autonomic ganglia (inside CNS ). (outside CNS). Preganglionic axons synapse with the postganglionic neurons Note: before the fibers reach the target, it should first pass by the autonomic ganglion and synapse ( interconnection).
    [Show full text]