disorders of the nervous system a primer

... Central nervous system (CNS) • Brain and spinal cord • Integration and command center • Peripheral nervous system (PNS) • Paired spinal and cranial nerves carry messages to and from the CNS Trang ... 11.5a(a) Myelination of a nerve fiber (axon) Schwann cell cytoplasm Axon Neurilemma Myelin sheath Schwann cell nucleus Schwann cell plasma membrane 1 2 3 A Schwann cell envelopes an axon. The ... Participate in information processing in the brain Trang 13Copyright © 2010 Pearson Education, Inc. Figure 11.3a(a) Astrocytes are the most abundantCNS neuroglia Capillary Neuron Astrocyte Trang

Ngày tải lên: 20/01/2020, 21:13

... cochlea by acting as vibra-a trvibra-ansformer thvibra-at mvibra-atches the impedvibra-ance of the vibra-air to thvibra-at of the cochlevibra-a The middleear is the only part of the entire auditory ... physiological abnormalities in other parts of the central nervous system than the clas-sical auditory pathways A part of the auditory nervous system, known as the non-classical, or extralemniscal, auditory ... provides the basis for a broad understanding of the anatomy and function of the ear and the auditory nervous system, and it discusses the cause and treatment of hearing disorders Most books on hearing

Ngày tải lên: 11/08/2014, 06:21

... The ear canal acts as a resonator, which causes the sound pressure at the tympanic membrane to be higher than it is at the entrance of the ear canal The gain is largest near 3 kHz (the resonance ... of the ear canal on the sound pressure at the tympanic membrane: (A) average differ-ence between the sound pressure at the tympanic membrane and that measured at the entrance of the ear canal; ... impedance transformer action of the middle ear is mainly accomplished by the ratio between theeffective area of the tympanic membrane and the area of the stapes footplate, but the lever ratio of the

Ngày tải lên: 11/08/2014, 06:21

... between the clas-sical and the non-clasclas-sical auditory pathways While the ICC is a part of the classical ascending auditory system the ICX and the DC are parts of the non-classical auditory system ... 5.10) rather than the primary auditory cortex (AI) that is the target of the classical pathways Another pathway from the IC to the primary cortex is via the posterior nucleus of the thalamus that ... and they are not as clearly organized anatomi-cally as those of the classical ascending pathways The use of the term “the polysensory system” reflectsthe finding that the non-classical pathways

Ngày tải lên: 11/08/2014, 06:21

... farfrom the anatomical location of their generators,such as the surface of the scalp 8 Neural activity in many of the structures of theclassical ascending auditory pathways, but not all,give ... nerve in a small animal, such as the cat,is approximately 0.8 cm long [59] The difference between the latency of the N1 of the AP and that of the response from the intracranial portion of the auditory ... is the (dorsal) surface of the dorsal cochlear nucleus and the rostral portion of the floor of the lateral recess is the dorsal surface of the ventral cochlear nucleus [119] When the lat-eral

Ngày tải lên: 11/08/2014, 06:21

... than the response to 0.5 kHz tones [182] The latency of the ipsilateral and the contralateral responses are similar The latency of the change in the acoustic impedance is the sum of the neural ... columns, one ear was stimulated The solid lines are the impedance change in the ipsilateral ear and the dashed lines are the impedance change in the contralateral ear The right-hand columns show ... than by long tones The response to short tones alsoreaches a plateau at a lower response amplitude thanthat to long tones, and the response to contralateralstimulation reaches a plateau at a

Ngày tải lên: 11/08/2014, 06:21

... distribution The mean value and stan-dard deviation are therefore not adequate descriptions of the hearing loss as a function of age Despite that,mean and median values of hearing loss are com-monly the ... evidence that the enhancement of sound fromthe resonance of the ear canal [246] is the cause of theselective damage Ear-canal resonance amplifies sounds in the region of 3 kHz (cf Chapter 2) That the ... in the internal states of a population of cells Ongoing mutations are another source of varia-tions that can manifest as differences in the physical characteristic of genetically identical organisms

Ngày tải lên: 11/08/2014, 06:21

... physical sounds that reach the ear in a normal way Information that travels in the classical pathways reaches the AII and association cor-tices before information that travels in the classicalpathways ... Establishment of subcortical connections from the audi-tory pathways to the lateral nucleus of the amygdala may be the cause of phonophobia Auditory information can normally reach the lateral nucleus of the ... medical treatments such as administration ofbenzodiazepines (Alprazalam, Clonazepam) [332] thatare GABAAreceptor agonists aim at restoring the bal-ance between inhibition and excitation in the brain

Ngày tải lên: 11/08/2014, 06:21

... Antibody screening — Well­characterized paraneoplastic antibodies against intracellular antigens (classical paraneoplastic or onconeuronal antibodies) are almost always detectable in serum; only in rare instances will the ... Although a pathogenic role of most classical paraneoplastic antibodies has not been proven, their presence indicates the paraneoplastic nature of a neurologic disorder, and in many cases, can narrow the search for an ... not exclude a paraneoplastic syndrome; however, the presumptive diagnosis requires the absence of the metastatic and nonmetastatic complications such as brain or leptomeningeal metastases and toxic effects of prior therapies In the absence of characteristic antibodies in the serum, specific diagnostic tests may be helpful for some

Ngày tải lên: 10/03/2017, 16:06

... immediately enters the airway tree at the mouth, but the gas first entering the alveoli at the start of inhalation is that same alveolar gas in the conducting airways that had just left the alveoli ... as an intravascular contrast agent for MR angiography (MRA); however, synchronization of data acquisition with the peak arterial bolus is one of the major challenges of MRA The flow of contrast ... such as animal fur and pollens Asthma can present at any age, with a peak age of 3 years In child-hood, twice as many males as females are asthmatic, but by adulthood the sex ratio has equalized

Ngày tải lên: 26/05/2017, 22:34

... use of the word ganglion (plural = ganglia) that has a historical explanation In the central nervous system, there is a group of nuclei that are connected together and were once called the basal ... sympathetic and parasympathetic ganglia The enteric nervous system includes the nervous tissue within the organs of the digestive tract. Visit this site to read about a woman that notices that ... is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral cavity of the vertebral column It is a bit of an oversimplification to say that the CNS

Ngày tải lên: 30/10/2017, 23:13

... B Each a and b chain of the T cell receptor (TCR) contains both a constant and a variable domain The variable domain contains short stretches of amino acids where the variability between different ... 2 in the a chain, 2 in the b chain 8 Congenic regions: 1 in the a chain, 1 in the b chain 9 One peptide-binding groove formed by the a chain and the b2-microglobulin chain ANS: B Each a and ... and both participate in early signal transduction events via cytoplasmic tail binding of the Src family tyrosine kinase Lck 11 A 15-year-old girl develops malaise, headache, and low-grade fever,

Ngày tải lên: 01/03/2019, 09:51

... Action potential arrives at axon terminal. Voltage-gated Ca 2+ channels open and Ca 2+ enters the axon terminal. Ca 2+ entry causes neurotransmitter- containing synaptic vesicles to release ... potential arrives at axon terminal. Voltage-gated Ca 2+ channels open and Ca 2+ enters the axon terminal. Ca 2+ entry causes neurotransmitter- containing synaptic vesicles to release their ... 2010 Pearson Education, Inc. Figure 11.17 Action potential arrives at axon terminal. Voltage-gated Ca 2+ channels open and Ca 2+ enters the axon terminal. Ca 2+ entry causes neurotransmitter-

Ngày tải lên: 20/01/2020, 06:02

... types of reactions of the innate immune system are inflamma- tion and antiviral defense Inflammation consists of the accumulation and activation of leukocytes and plasma proteins at sites of infec-tion ... editor, James Merritt, has been an enthusiastic source of encouragement and advice Our two talented illustrators, David Trang 10and Alexandra Baker of DNA Illustrations, have revamped all the artwork ... through the epithelia of the skin and gastrointestinal and respiratory systems The earliest defense mechanisms active at these sites are epi-thelia providing physical barriers and anti-microbial molecules

Ngày tải lên: 21/01/2020, 14:12

... structurally similar to a component of C1 of the classical pathway and serves to activate C4 The subsequent steps are essentially the same as in the classical pathway The net result of these early ... polysaccha-rides These are called conjugate vaccines, and they are excellent examples of the practical application of our knowledge of helper T cell–B is characterized by waves of parasitemia, each wave ... called the alternative and lectin pathways, are initiated by microbes in the absence of antibody, and the third, called the classical pathway, is initiated by certain isotypes of antibodies attached

Ngày tải lên: 22/01/2020, 03:31

... reduces the negative membrane potential slightly The permeabilities of Na + and K + across the membrane are different. The concentrations of Na + and K + on each side of the membrane are different. ... plasma membrane (without voltage-gated channels), as on a dendrite, voltage decays because current leaks across the membrane. (b) In an unmyelinated axon, voltage-gated Na + and K + channels ... adjacent regions Trang 23Copyright © 2010 Pearson Education, Inc. Figure 11.10aDepolarized region Stimulus Plasma membrane (a) Depolarization: A small patch of the membrane (red area) has

Ngày tải lên: 23/01/2020, 18:00

... endothelium 18 Binds to ICAM-1 on the surface of a variety of cells, mediating firm adhesion Trang 16between T cells and APCs or endothelial cells 19 Binds to VCAM-1 on the surface of cytokine-activated ... cytokine-activated endothelium In a 17 CD44 expressed on the surface of T cells is critical for the binding of activated T cells to endothelium at sites of inflammation, and for the retention of ... interactions between activated T helper cells and macrophages 23 LFA-1–ICAM-1 interactions between activated T cells and macrophages Trang 20intracellular microbes such as Listeria CD28-B7 and

Ngày tải lên: 17/12/2020, 17:37

... described by Barbara Ranscht and colleagues as a member of the Cadherin family of calcium dependant cell adhesion molecules (Ranscht and Trang 23with other classical cadherins (43% amino acid identity ... studied anatomy of the system (Nakao and Ishizawa, 1994) and the already described spatial and temporal regulation of T-cadherin expression (Ranscht and Bronner-Fraser, 1991; Fredette and Ranscht, ... Patterned development of motor pathways The motor axon pathway is a good model system for elucidating the function of T-cadherin as an axon guidance cue both because of the carefully studied anatomy

Ngày tải lên: 02/10/2024, 01:39

... of India.Angiography is the examination of the arteries andveins that carry blood to the various parts of the body Now-a-days, even a layman is also aware of the angiography ofthe heart The blood ... dedication towards his profession as well as his skill and high character are vital. Also the care and kindness of nursing staff in the ward areequally important Trang 22The care and warmth of family ... friends and relatives, prayers, the social atmosphere of the home andaccurate information regarding the disease also play important role in the restoration of the health of the patient.All these

Ngày tải lên: 12/12/2016, 09:55

... of India.Angiography is the examination of the arteries andveins that carry blood to the various parts of the body Now-a-days, even a layman is also aware of the angiography ofthe heart The blood ... dedication towards his profession as well as his skill and high character are vital. Also the care and kindness of nursing staff in the ward areequally important Trang 22The care and warmth of family ... friends and relatives, prayers, the social atmosphere of the home andaccurate information regarding the disease also play important role in the restoration of the health of the patient.All these

Ngày tải lên: 01/04/2017, 10:41