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The Central and Peripheral Nervous Systems marieb testbank
The Central and Peripheral Nervous Systems marieb testbank
Question About Peripheral Nervous System
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other organs, the parenchymal flow in the brain is controlled entirely outside of the organ. Two-thirds of the vascular resistance in the brain is due to large cerebral arteries and pial vessels [4]; non-pial vessels are responsible for the remaining one-third of vas- cular resistance [4].
Furthermore, the brain capillary system is highly heterogeneous. The brain uses an additional mechanism, hyperaemia, to increase the flow of blood to the regions in which neurons are active. According to this mechanism, neurons and astrocytes dir- ectly regulate the local blood flow within the capillaries, resulting in local neurovascular coupling. Initially, it was proposed that the local increase in blood flow upon neuronal activation was caused by a metabolic
The Structure and Functions of the Arteries Arteries are blood vessels that convey blood from the heart to the tissues of the body. The arteries expand and then constrict with each beat of the heart, a rhythmic movement that may be felt as the pulse. Arteries are usually named from the part of the body that they are found, for example; brachial artery found in the arms, metacarpal artery found in the wrist; or from the organ which they supply as the hepatic artery supplies the liver, pulmonary artery brings deoxygenated blood the lungs. The facial artery is the branch of the external carotid artery that passes up over the lower jaw and supplies the superficial portion of the face; the haemorrhoidal arteries are three vessels that supply the lower end of the rectum; the intercostal arteries are the arteries that supply the space between the ribs; the lingual artery is the branch of the external carotid artery that supplies the tongue. The structure of the artery enables it to perform its function more efficiently.
When it comes to death, everyone has a different perspective about it. One might think death is just a beginning, a key to open the door to the afterlife. A release, a way out to a different world. Others might think that death is simply a lesson of life. It teaches one not to waste his or her time but live to enjoy it, while it still last. Live and do whatever one desire before time runs out. Surely, death has many different purposes and meanings. In the short story “Bullet in the Brain” by Tobias Wolff. He uses death as a flashback and a final thought to show the reader the character’s life in the story. In the “An Occurrence at Owl Creek Bridge” by Ambrose Bierce, he uses death to teach the reader that one should stand up and protect the
There is progressive vasoconstriction of arterioles until the BP exceeds the upper limit of auto regulation, followed by breakthrough vasodilation, increase in cerebral blood flow, blood-brain barrier dysfunction, and cerebral oedema(Rodriguez-Yanez et al., 2006). Cerebral ischemia results in severely ischemic tissue with failure of electrical activity and ionic pumps (Rodriguez-Yanez et al., 2006) There is increase in the release of the excitatory amino acid glutamate due to electrical failure. (Rodriguez-Yanez et al., 2006) . Glutamate receptors are activated as a result and cause the opening of ion channels that allow potassium ions to leave the cell and sodium and calcium ions to enter. This has a number of physiological effects.
Firstly, there is various of sensing activities as in seeing and hearing as in a sense of understanding of what is seen and heard. Secondly the sense of feeling in numerous parts of the body from the head to the toes. The ability to recall past events, the sophisticated emotions and the thinking process. The cerebellum acts as a physiological microcomputer which intercepts various sensory and motor nerves to smooth out what would otherwise be jerky muscle motions. The medulla controls the elementary functions responsible for life, such as breathing, cardiac rate and kidney functions. The medulla contains numerous of timing mechanisms as well as other interconnections that control swallowing and salivations.
Blood is supplied to each meniscus by the medial genicular artery. Each meniscus can be divided into three circumferential zones: the red-red zone is the outer or peripheral one third and has a good vascular supply; the red-white zone is the middle one third and has a minimal blood supply; and the white-white zone on the inner one third is avascular (Arnheim,1997).
Rowland, L. P., ed. Merritt’s Textbook of Neurology. 7th ed. Lea and Febiger. Philadelphia: 1984.
The brain has many different parts to it which help one function through daily life; parts such as the cerebrum which controls voluntary movement and regulates functions such as thinking, speaking and the ability to recall information. The cerebellum controls the balance and coordination and finally the brain stem, which consists of the medulla oblongata and the spinal cord which controls all involuntary functions such as breathing, heart rate and blood pressure. The brain stem is also able to carry out these actions even when someone is asleep. To fully understand how crucial the brain is to survival one must understand the functions of the brain stem.
Culter, Mary Ann, Joanne Dombrowski, Michael Doughtery, Paula Henderson, and Laura McNicholas. “The brain: understanding nuerobiology. The brain-lesson1-What does this part of the brain do?” NIH publication, Mar.20120.21.Apr.2014.
be as high as 80% in Erythrocytes, and as low as 18% in myelinated neurones.
Martini, Nath, Bartholomew. (2012). Fundamentals of Anatomy and Physiology Ninth Edition. In N. B. Martini, Fundamentals of Anatomy and Physiology Ninth Edition (pp. Chapter 25; 917-952). San Francisco: Pearson Education.
Other problems with using these noninvasive imaging methods of only few changes of variables in the brain’s activity are that maybe the problem does not reside in the blood, oxygen intake, or glucose utilization. It may be in other factors that we do not observe that is causing the trouble. By being limited to these estimations of brain activity does not really make our effort of correcting the problem that successful.
Chemoreceptors detect altered blood gas levels, and so send signals to the CNS to rectify this problem by altering the breathing. The relevant parts of the brain deal with this issue, particularly the medulla and the pons. The medulla oblongata has a major role to play in the regulation of breathing, as it does in the controlling many autonomic body functions – functions not under our conscious control (unlike many of the others, ventilation can be consciously controlled by the cerebral cortex, but this can be overridden). The medulla possesses the respiratory centre of the brain, and upon receiving the signals from chemoreceptors, it reacts by sending a signal to the respiratory muscles, altering their action to compensate for the blood gas
It is estimated that for each action potential in a rodent cortical pyramidal neuron, about four hundred million ATP molecules are used in the restoring of Na+ and K+ gradients. This absurd sounding number makes action potential signaling the second largest metabolic cost associated with mammal brain functions (Hallermann, de Knock, Stuart, & Kole, 2012). The authors of the article “State and location dependence of action potential metabolic cost in cortical pyramidal neurons”, published in Nature Neuroscience, investigated the location and voltage dependence of this metabolic cost in rat neocortical pyramidal neurons. They hypothesized that action potential metabolic cost is not still and does depend on the state of network activity and tested their hypothesis by preforming a series of computer modeling/ simulations and lab tests of pyramidal neurons using direct Na+ and K+ current recordings at various locations on neurons and various physical states. This paper is going to summarize and review the experiments and writings of the article “State and location dependence of action potential metabolic cost in cortical pyramidal
The cranium provides maximum protection with minimum weight, the ideal combination. The other twenty bones make up the face, jaw and other parts of the skull. Another way the brain keeps it self safe is by keeping itself in liquid. Nearly one fifth of the blood pumped by the heart is sent to the brain. The brain then sends the blood through an intricate network of blood vessels to where the blood is needed. Specialized blood vessels called choroid plexuses produce a protective cerebrospinal fluid.
The parasympathetic is controlled by the cranial part of the brain, that is the vagus nerve and the sacral nerves arising from the spinal cord where the nerve fibers are distributed all over the body. The parasympathetic innervation for the activity of the thoracic cavity is decreased with connected glands and organs in the abdomen. The sacral component control or mediates the activity of the colon, bladder and the rectum. The parasympathetic nervous system has no connection with blood vessels except with brain and genitals. But they cause the stimulation to release neurotransmitter nitric oxide from blood vessels. The parasympathetic nervous system decreases the heart rate and blood pressure by vasodilation.