Human Brain Anatomy And Physiology PdfBy Marine B. In and pdf 21.03.2021 at 18:49 7 min read
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- Human brain
- Brain 101: An Overview of the Anatomy and Physiology of the Brain
- Human Brain: Facts, Functions & Anatomy
While stress itself is not necessarily problematic, the buildup of cortisol in the brain can have long-term effects. In , researchers from Harvard found that certain parts of the brain were differently sized in males and females, which may help balance out the overall size difference.
The human brain is the command center for the human nervous system. It receives signals from the body's sensory organs and outputs information to the muscles. The human brain has the same basic structure as other mammal brains but is larger in relation to body size than any other brains. The largest part of the human brain is the cerebrum, which is divided into two hemispheres, according to the Mayfield Clinic. Underneath lies the brainstem, and behind that sits the cerebellum.
The human brain is the central organ of the human nervous system , and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum , the brainstem and the cerebellum. It controls most of the activities of the body , processing, integrating, and coordinating the information it receives from the sense organs , and making decisions as to the instructions sent to the rest of the body.
The brain is contained in, and protected by, the skull bones of the head. The cerebrum is the largest part of the human brain. It is divided into two cerebral hemispheres. The cerebral cortex is an outer layer of grey matter , covering the core of white matter. The cortex is split into the neocortex and the much smaller allocortex. The neocortex is made up of six neuronal layers , while the allocortex has three or four.
Each hemisphere is conventionally divided into four lobes — the frontal , temporal , parietal , and occipital lobes. The frontal lobe is associated with executive functions including self-control , planning , reasoning , and abstract thought , while the occipital lobe is dedicated to vision. Within each lobe, cortical areas are associated with specific functions, such as the sensory , motor and association regions. Although the left and right hemispheres are broadly similar in shape and function, some functions are associated with one side , such as language in the left and visual-spatial ability in the right.
The hemispheres are connected by commissural nerve tracts , the largest being the corpus callosum. The cerebrum is connected by the brainstem to the spinal cord. The brainstem consists of the midbrain , the pons , and the medulla oblongata. The cerebellum is connected to the brainstem by pairs of tracts. Within the cerebrum is the ventricular system , consisting of four interconnected ventricles in which cerebrospinal fluid is produced and circulated.
Underneath the cerebral cortex are several important structures, including the thalamus , the epithalamus , the pineal gland , the hypothalamus , the pituitary gland , and the subthalamus ; the limbic structures , including the amygdala and the hippocampus ; the claustrum , the various nuclei of the basal ganglia ; the basal forebrain structures, and the three circumventricular organs.
The cells of the brain include neurons and supportive glial cells. There are more than 86 billion neurons in the brain, and a more or less equal number of other cells. Brain activity is made possible by the interconnections of neurons and their release of neurotransmitters in response to nerve impulses.
Neurons connect to form neural pathways , neural circuits , and elaborate network systems. The whole circuitry is driven by the process of neurotransmission. The brain is protected by the skull , suspended in cerebrospinal fluid , and isolated from the bloodstream by the blood—brain barrier.
However, the brain is still susceptible to damage , disease , and infection. Damage can be caused by trauma , or a loss of blood supply known as a stroke. The brain is susceptible to degenerative disorders , such as Parkinson's disease , dementias including Alzheimer's disease , and multiple sclerosis. Psychiatric conditions , including schizophrenia and clinical depression , are thought to be associated with brain dysfunctions. The brain can also be the site of tumours , both benign and malignant ; these mostly originate from other sites in the body.
The study of the anatomy of the brain is neuroanatomy , while the study of its function is neuroscience. Numerous techniques are used to study the brain. Specimens from other animals, which may be examined microscopically , have traditionally provided much information.
Medical imaging technologies such as functional neuroimaging , and electroencephalography EEG recordings are important in studying the brain. The medical history of people with brain injury has provided insight into the function of each part of the brain. Brain research has evolved over time, with philosophical, experimental, and theoretical phases.
An emerging phase may be to simulate brain activity. In culture, the philosophy of mind has for centuries attempted to address the question of the nature of consciousness and the mind-body problem. The pseudoscience of phrenology attempted to localise personality attributes to regions of the cortex in the 19th century.
In science fiction, brain transplants are imagined in tales such as the Donovan's Brain. The adult human brain weighs on average about 1. The cerebrum , consisting of the cerebral hemispheres , forms the largest part of the brain and overlies the other brain structures. Each hemisphere is divided into four main lobes — the frontal lobe , parietal lobe , temporal lobe , and occipital lobe.
The brainstem , resembling a stalk, attaches to and leaves the cerebrum at the start of the midbrain area. The brainstem includes the midbrain, the pons , and the medulla oblongata.
Behind the brainstem is the cerebellum Latin : little brain. The cerebrum, brainstem, cerebellum, and spinal cord are covered by three membranes called meninges. The membranes are the tough dura mater ; the middle arachnoid mater and the more delicate inner pia mater. Between the arachnoid mater and the pia mater is the subarachnoid space and subarachnoid cisterns , which contain the cerebrospinal fluid.
The cerebrum is the largest part of the brain, and is divided into nearly symmetrical left and right hemispheres by a deep groove, the longitudinal fissure.
There are many small variations in the secondary and tertiary folds. The outer part of the cerebrum is the cerebral cortex , made up of grey matter arranged in layers. It is 2 to 4 millimetres 0. The largest part of the cerebral cortex is the neocortex , which has six neuronal layers. The rest of the cortex is of allocortex , which has three or four layers. The cortex is mapped by divisions into about fifty different functional areas known as Brodmann's areas. These areas are distinctly different when seen under a microscope.
The primary sensory areas receive signals from the sensory nerves and tracts by way of relay nuclei in the thalamus. Primary sensory areas include the visual cortex of the occipital lobe , the auditory cortex in parts of the temporal lobe and insular cortex , and the somatosensory cortex in the parietal lobe. The remaining parts of the cortex, are called the association areas. These areas receive input from the sensory areas and lower parts of the brain and are involved in the complex cognitive processes of perception , thought , and decision-making.
The temporal lobe controls auditory and visual memories , language , and some hearing and speech. The cerebrum contains the ventricles where the cerebrospinal fluid is produced and circulated. Below the corpus callosum is the septum pellucidum , a membrane that separates the lateral ventricles. Beneath the lateral ventricles is the thalamus and to the front and below this is the hypothalamus.
The hypothalamus leads on to the pituitary gland. At the back of the thalamus is the brainstem. The basal ganglia , also called basal nuclei, are a set of structures deep within the hemispheres involved in behaviour and movement regulation. The ventral striatum consists of the nucleus accumbens and the olfactory tubercle whereas the dorsal striatum consists of the caudate nucleus and the putamen.
The putamen and the globus pallidus lie separated from the lateral ventricles and thalamus by the internal capsule , whereas the caudate nucleus stretches around and abuts the lateral ventricles on their outer sides. Below and in front of the striatum are a number of basal forebrain structures.
These include the nucleus basalis , diagonal band of Broca , substantia innominata , and the medial septal nucleus. These structures are important in producing the neurotransmitter , acetylcholine , which is then distributed widely throughout the brain. The basal forebrain, in particular the nucleus basalis, is considered to be the major cholinergic output of the central nervous system to the striatum and neocortex. The cerebellum is divided into an anterior lobe , a posterior lobe , and the flocculonodular lobe.
It is connected to the midbrain of the brainstem by the superior cerebellar peduncles , to the pons by the middle cerebellar peduncles , and to the medulla by the inferior cerebellar peduncles. The brainstem lies beneath the cerebrum and consists of the midbrain , pons and medulla. It lies in the back part of the skull , resting on the part of the base known as the clivus , and ends at the foramen magnum , a large opening in the occipital bone.
The brainstem continues below this as the spinal cord ,  protected by the vertebral column. Ten of the twelve pairs of cranial nerves [a] emerge directly from the brainstem.
The human brain is primarily composed of neurons , glial cells , neural stem cells , and blood vessels. Types of neuron include interneurons , pyramidal cells including Betz cells , motor neurons upper and lower motor neurons , and cerebellar Purkinje cells.
Betz cells are the largest cells by size of cell body in the nervous system. Types of glial cell are astrocytes including Bergmann glia , oligodendrocytes , ependymal cells including tanycytes , radial glial cells , microglia , and a subtype of oligodendrocyte progenitor cells. Astrocytes are the largest of the glial cells. They are stellate cells with many processes radiating from their cell bodies. Some of these processes end as perivascular end-feet on capillary walls.
Mast cells are white blood cells that interact in the neuroimmune system in the brain. Some genes are shown to be brain-specific.
Cerebrospinal fluid is a clear, colourless transcellular fluid that circulates around the brain in the subarachnoid space , in the ventricular system , and in the central canal of the spinal cord. It also fills some gaps in the subarachnoid space, known as subarachnoid cisterns.
From here, cerebrospinal fluid circulates around the brain and spinal cord in the subarachnoid space, between the arachnoid mater and pia mater. It is constantly being regenerated and absorbed, and is replaced about once every 5—6 hours.
A glymphatic system has been described    as the lymphatic drainage system of the brain. The brain-wide glymphatic pathway includes drainage routes from the cerebrospinal fluid, and from the meningeal lymphatic vessels that are associated with the dural sinuses, and run alongside the cerebral blood vessels.
The internal carotid arteries supply oxygenated blood to the front of the brain and the vertebral arteries supply blood to the back of the brain. The internal carotid arteries are branches of the common carotid arteries. They enter the cranium through the carotid canal , travel through the cavernous sinus and enter the subarachnoid space.
These branches travel forward and then upward along the longitudinal fissure , and supply the front and midline parts of the brain.
Brain 101: An Overview of the Anatomy and Physiology of the Brain
The brain is a fascinating and complex organ. It is responsible for senses, movement and control, emotions and feelings, language and communication, thinking and memory. Research of the brain and understanding the inner workings of the brain will help us to learn about the mechanisms of certain neurological conditions, including hydrocephalus. Increasing our own knowledge of the brain helps us understand our own bodies better and helps us have informed conversations with our doctors, be it as a patient or a caregiver. To celebrate BAW we present a two-part blog to increase our understanding of the brain and how the brain is impacted by hydrocephalus.
The brain carries out cognitive learning and processing by performing combinations of different types of information processes. Types of information processes are performed by different anatomical structures and implemented in physiology. The information processes performed by different major anatomical structures including the cortex, basal ganglia, thalamus and cerebellum are described, including their implementations in neuron physiology. The implications for the architecture and design of a general intelligence system are discussed. Unable to display preview. Download preview PDF. Skip to main content.
Human Brain: Facts, Functions & Anatomy
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head , usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 14—16 billion neurons ,  and the estimated number of neurons in the cerebellum is 55—70 billion. These neurons typically communicate with one another by means of long fibers called axons , which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.
The brain is an amazing three-pound organ that controls all functions of the body, interprets information from the outside world, and embodies the essence of the mind and soul. Intelligence, creativity, emotion, and memory are a few of the many things governed by the brain.
Пока. Есть вести от Дэвида. Стратмор покачал головой.
Нужно было думать о долге - о стране и о чести. Стратмор полагал, что у него еще есть время. Он мог отключить ТРАНСТЕКСТ, мог, используя кольцо, спасти драгоценную базу данных.
И ради этого стоило убивать. Когда Беккер наконец вышел из Гиральды в Апельсиновый сад, утреннее солнце уже нещадно пекло. Боль в боку немного утихла, да и глаза как будто обрели прежнюю зоркость. Он немного постоял, наслаждаясь ярким солнцем и тонким ароматом цветущих апельсиновых деревьев, а потом медленно зашагал к выходу на площадь. В этот момент рядом резко притормозил мини-автобус.
Я отправил Дэвида в Испанию.