Overview Of Anatomy And Physiology
- Compare and contrast anatomy and physiology, including their specializations and methods of study
- Discuss the fundamental relationship between anatomy and physiology
Human anatomy is the scientific study of the bodys structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope. Other larger structures can readily be seen, manipulated, measured, and weighed. The word anatomy comes from a Greek root that means to cut apart. Human anatomy was first studied by observing the exterior of the body and observing the wounds of soldiers and other injuries. Later, physicians were allowed to dissect bodies of the dead to augment their knowledge. When a body is dissected, its structures are cut apart in order to observe their physical attributes and their relationships to one another. Dissection is still used in medical schools, anatomy courses, and in pathology labs. In order to observe structures in living people, however, a number of imaging techniques have been developed. These techniques allow clinicians to visualize structures inside the living body such as a cancerous tumor or a fractured bone.
Figure 1.2 Gross and Microscopic Anatomy Gross anatomy considers large structures such as the brain. Microscopic anatomy can deal with the same structures, though at a different scale. This is a micrograph of nerve cells from the brain. LM × 1600.
Wimsatts Local Maxima Account
Both the layer-cake and the mechanistic approach to levels aim atdefining levels in the sense of giving at least necessary conditionsfor what constitutes a level. William Wimsatt takes a different approachand sets out to characterize the key features that levels oforganization typically exhibit across differentinstances. His aim is to delineate major structural or organizationalfeatures of nature, of which levels of organization are the mostsalient ones. First, levels are compositional and form nestedhierarchical structures, so that wholes at lower levels function asparts at higher levels. Second, levels of organization are a
deep, non-arbitrary, and extremely important feature of theontological architecture of our natural world, and almost certainly ofany world which could produce, and be inhabited or understood by,intelligent beings.
In other words, Wimsatt considers levels to be units that cutnature at its joints .
A further feature of levels of organization is that they are
constituted by families of entities usually of comparable size anddynamical properties, which characteristically interact primarily withone another.
Finally, and perhaps most importantly,
evels of organization can be thought of as local maxima ofregularity and predictability in the phase space of alternative modesof organization of matter.
Figure. Wimsatt, created in 1973 usedwith permission.
The Neurophysiology Of Dissipation
The question of how brain free energy changes with healthy or pathological brain states can be inspected from another perspective. It has been proposed that brain dissipates energy in order to process information . As a dissipative structure, the nervous system should then dissipate energy efficiently to function properly, and the question becomes whether there is a relation of dissipation with healthy and pathological conditions. Building on the studies of Bak et al. on the energy dissipated during avalanches, some considerations can be obtained about brain dynamics especially reflecting on energy dissipated in the process of synchronization of brain cell networks and how it changes with neuropathology. The authors propose that the size of an avalanche is proportional to the instantaneous energy dissipation rate. In neuroscience, neural avalanches have been considered in the literature, normally as bursts of activity in neuronal networks . Those bursts of activity occur due to neurons receiving synchronous inputs from other connected cells, thus, in the final analysis the bursts represent manifestations of synchronization of cellular activity, which naturally correlate with the amplitude of the extracellular field potentials: large amplitudes represent more synchronous cellular activity hence, synchrony and magnitude of local field potentials are very much related.
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The Architecture Of The Brain
The brain is like a committee of experts. All the parts of the brain work together, but each part has its own special properties. The brain can be divided into three basic units: the forebrain, the midbrain, and the hindbrain.
The hindbrain includes the upper part of the spinal cord, the brain stem, and a wrinkled ball of tissue called the cerebellum . The hindbrain controls the bodys vital functions such as respiration and heart rate. The cerebellum coordinates movement and is involved in learned rote movements. When you play the piano or hit a tennis ball you are activating the cerebellum. The uppermost part of the brainstem is the midbrain, which controls some reflex actions and is part of the circuit involved in the control of eye movements and other voluntary movements. The forebrain is the largest and most highly developed part of the human brain: it consists primarily of the cerebrum and the structures hidden beneath it .
When people see pictures of the brain it is usually the cerebrum that they notice. The cerebrum sits at the topmost part of the brain and is the source of intellectual activities. It holds your memories, allows you to plan, enables you to imagine and think. It allows you to recognize friends, read books, and play games.
What Level Of Organization Is The Brain
The highest level of organization for living things is the biosphere it encompasses all other levels. The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.
Additionally, what are the levels of organization with examples? The levels, from smallest to largest, are: molecule, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.
Also to know, what are the 5 levels of organization in order?
There are five levels: cells, tissue, organs, organ systems, and organisms. All living things are made up of cells. This is what distinguishes living things from other objects.
What are the 4 levels of organization in the body?
Life processes of the human body are maintained at several levels of structural organization. These include the chemical, cellular, tissue, organ, organ system, and the organism level. Higher levels of organization are built from lower levels.
Terms in this set
- Atomic/chemical. Smallest unit/all chems composing the human body.
- Organelle. Components that make up a cell.
- Cellular. Cells are basic structural and functional units of the body.
- Tissue. Similar cells grouped together for similar functuon.
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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.
Grns In Social Behavior
A special focus of behavioral transcriptomics during its first two decades has been social behavior, from both mechanistic and evolutionary perspectives . Should we expect fundamental differences in bGRNs related to social behavior relative to those associated with other types of behaviors? Treating bGRNs as a mapping of inputs to outputs , a reasonable null hypothesis is that it should not matter whether the inputs were triggered by a social or nonsocial stimulus. According to this logic, there is nothing special about social bGRNs relative to other types of bGRNs for behaviors that do not involve social interactions among conspecifics, such as food acquisition or nest construction in some species. On the other hand, there are also good reasons for anticipating differences between social bGRNs and other bGRNs. Social behavior involves repeated interactions between individuals, an iterative exchange of stimulus and response that is fundamentally different from a unidirectional intake of stimuli from abiotic sources. This adds yet another network layerthe social networkto the information-processing system, potentially leading to specialized patterns and dynamics in bGRN and NN activity, and hence to special structural properties of these networks.
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Levels Of Organization In Philosophical Debates
Levels of organization figure into a number of perennial debates inphilosophy of science. Here we go through three broad topics wherelevels traditionally have and continue to play a prominent role:Reduction, antireductionism and pluralism, and downward causation.Within these topics, we focus on issues and theories that directlyinvolve levels.
What Is The Gray Matter And White Matter
Gray and white matter are two different regions of the central nervous system. In the brain, gray matter refers to the darker, outer portion, while white matter describes the lighter, inner section underneath. In the spinal cord, this order is reversed: The white matter is on the outside, and the gray matter sits within.
Gray matter is primarily composed of neuron somas , and white matter is mostly made of axons wrapped in myelin . The different composition of neuron parts is why the two appear as separate shades on certain scans.
Each region serves a different role. Gray matter is primarily responsible for processing and interpreting information, while white matter transmits that information to other parts of the nervous system.
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Introduction A Possible Framework To Characterize Nervous System Dynamics And Its Organization
In the search for a simple unified conceptual framework to describe the organization of brain dynamics we aim to bind some results together into some sort of coherence with a central theme. We follow the thermodynamic approach: search for a state functional that reflects the nature of the states attained by the system and that is influenced by certain observables. Two main considerations are worth discussing in order to determine what constitutes the states of the brain, what observables can be measured and what level of description is the most relevant for the purposes of characterizing brain and behavior.
Figure 1. General scheme toward a possible framework to characterize brain dynamics in the search for a basic general principle of brain and behavior. See text for details.
Spatiotemporal Dimensions Of Bgrnnn Interplay
The interactions between NNs and bGRNs play out at multiple spatial and temporal scales. In the spatial dimension , the activities of bGRNs differ across brain regions and cell types each location may thus exhibit distinct gene expression changes during a specific behavior . bGRN activities at different locations also influence each other, e.g., via the NN and neuroendocrine signaling . Likewise, the NN is meshed across the entire nervous system, with even single neurons known to link distant regions . Thus, with both networks exhibiting spatial patterns of activity, their interplay will assume a level of complexity above and beyond that of either network alone. This may lead to an increased number of stable transcriptional states , as has been shown in computer simulations that connect each cells GRNs to a cellcell interaction network . Such higher-level interactions can also influence the stability of, and transitions between, attractors. This results in more dynamic gene expression profiles, an important anticipated feature of bGRNs, as noted above. A key direction for future efforts must be the coupling of real-time neural activity measurements with high-resolution single-cell transcriptomics in specific behavioral contexts.
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Organization Of The Nucleus And Its Dna
Like most other cellular organelles, the nucleus is surrounded by a membrane called the nuclear envelope. This membranous covering consists of two adjacent lipid bilayers with a thin fluid space in between them. Spanning these two bilayers are nuclear pores. A nuclear pore is a tiny passageway for the passage of proteins, RNA, and solutes between the nucleus and the cytoplasm. Proteins called pore complexes lining the nuclear pores regulate the passage of materials into and out of the nucleus.
Inside the nuclear envelope is a gel-like nucleoplasm with solutes that include the building blocks of nucleic acids. There also can be a dark-staining mass often visible under a simple light microscope, called a nucleolus . The nucleolus is a region of the nucleus that is responsible for manufacturing the RNA necessary for construction of ribosomes. Once synthesized, newly made ribosomal subunits exit the cells nucleus through the nuclear pores.
DNA MacrostructureFigure 4.
Organelles For Energy Production And Detoxification
In addition to the jobs performed by the endomembrane system, the cell has many other important functions. Just as you must consume nutrients to provide yourself with energy, so must each of your cells take in nutrients, some of which convert to chemical energy that can be used to power biochemical reactions. Another important function of the cell is detoxification. Humans take in all sorts of toxins from the environment and also produce harmful chemicals as byproducts of cellular processes. Cells called hepatocytes in the liver detoxify many of these toxins.
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Percolation Analysis And Thresholding
We used a variation of the percolation analysis proposed by ref. , recently developed by ref. : we ranked all experimentally determined correlation coefficients in increasing order one at a time we removed from the network the link corresponding to the actual correlation value in the list then we deleted it from the rank. Finally, step by step we explored the global organization of the network after each link removal by considering the number of its connected components. This enabled us to calculate connected components by systematically varying the threshold on the network. Among the possible thresholds we looked at those values associated with the plateaux showed in the curve of Fig. obtained by the percolation process. Specifically, we considered all correlation values corresponding to points in the distribution of the real plateaux length overcoming the mean plus four standard deviations of the distribution of plateaux length of the ensemble of randomizations. This procedure led to the definition of 23 values, for which stable configurations of brain networks were found.
Brain Development In The Postnatal Period
Though the production and migration of neurons are largely prenatal events, proliferation and migration of glial progenitors continues for an extended period after birth, and the differentiation and maturation of these cells continue throughout childhood. The full scope of neuron-glia interactions is still not fully defined, but it is clear that these interactions play an important role in functional organization of neural circuits during postnatal life. Importantly, estimates of the developmental time course in humans of the postnatal processes outlined below are derived by extrapolation from data acquired in other species, often rodents, and from very limited human postmortem material. Unfortunately, the result is much remaining uncertainty about the temporal extent of proliferation, migration, differentiation, and regression during the postnatal period in humans, and about the timing of these processes relative to each other. In vivo brain imaging of children is providing important clues about the time course of age-related biological alterations in the brain, and provides an opportunity to link these changes to evolving behavior.
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Thermodynamic Considerations Regarding Brain Dynamics In Conscious And Unconscious States
The aforementioned comments on the applicability of equilibrium concepts to the mesoscale level allow for the use of notions like free energy, using the standard Gibbs free energy equation G = ETS with E the internal energy, T the temperature and S the entropy . In general, for non-equilibrium systems, the terms in this formula are not the exact terms used in classical thermodynamics of equilibrium systems. For non-equilibrium one has to consider functionals of a similar form associated with a certain probability distribution P, G = E TS where E is some kind of internal energy, T is a noise term representing fluctuations, and S is an information measure like Shannon entropy, which is formally equivalent to the Gibbs entropy .
There has been a recent interest in the relevance of a free energy perspective on cognition . It is known that nature follows the path toward a decrease in free energy, the dissolution of energy gradients. It is crucial to note too that it is not absolute energy but the differences in energy that have physical meaning . At or near equilibrium the distribution of stationary states corresponds to those that minimize G. Along these lines, regarding the nervous system, it has been said that consciousness integrates sensory and other inputs to consume energy gradients more effectively than by unconscious deeds . Hence, is conscious awareness associated with lower free energy in the brain?
A Brief Digression On Possible Foundations For A Conceivable Nervous System Potential
It was mentioned above the usefulness of having a chemical potential to characterize the evolution of chemical reactions. J.W. Gibbs definition of chemical potential in 1875 allowed for the precise characterization of aspects like equilibrium and the investigation of the dynamics of chemical reactions. It could be of interest if some equivalent to the chemical potential could be described about the processes of the nervous systemespecially in its collective cellular activity at the meso/macroscale levela concept that could help understand the evolution of brain activity and its relation to behavioral dispositions. It was described above that in the expression for the entropy production dS/dt the term Ni could be taken as pairwise connected brain networks instead of molecules. Hence, the basic intuition behind the idea to develop an analog to chemical potential for the brain is that connected cell ensembles are analogous to molecular concentrations in chemistry.
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Cells: The Building Blocks Of The Body
After organelles and macromolecules, cells are the most basic part of the human body, and they are the foundation of structure and function in the body. Every person has around 100 trillion cells, by the time that they grow into adulthood. Every cell will carry out a special function that allows the body to survive, but they wont all carry out the same function. Cells are specialized in function and in their form, with the different types of cells carrying out different roles.
Nerve cells have long projections called axons, which carry electrical signals throughout the body and to other cells. Meanwhile, muscle cells have many mitochondria so that they can generate the energy the body needs to move. Epithelial cells, also known as skin cells, serve as a protective barrier between interior organs and the outside world, helping to regulate body temperature and prevent infections. Sex cells, or gametes, exist in two different varieties: sperm cells and eggs. These sex cells are what allow reproduction and the passing on of genetic material.