But how can this mass of cells control our moods, our behaviours, our addictions? And what happens if this mass. Clinical Neuroanatomy. Connections define the functions of neurons: information flows along connections, as well as growth factors and viruses, and even neuronal death may progress through connections. Knowledge of how the various parts of the brain are interconnected to form functional systems is a prerequisite for the proper understanding of data from.
Connections define the functions of neurons: information flows along connections, as well as growth factors and viruses, and even neuronal death can progress through connections. Accordingly, knowing how the various parts of the brain are interconnected to form functional systems is a prerequisite for properly understanding data from all fields. Messages can travel from one gyrus to another, from one lobe to another, from one side of the brain to the other, and to structures found deep in the brain e.
Deep structures Hypothalamus - is located in the floor of the third ventricle and is the master control of the autonomic system. It plays a role in controlling behaviors such as hunger, thirst, sleep, and sexual response. It also regulates body temperature, blood pressure, emotions, and secretion of hormones. Pituitary gland - lies in a small pocket of bone at the skull base called the sella turcica. The pituitary gland is connected to the hypothalamus of the brain by the pituitary stalk.
It secretes hormones that control sexual development, promote bone and muscle growth, respond to stress, and fight disease. Figure 5. Coronal cross-section showing the basal ganglia. Pineal gland - is located behind the third ventricle. It has some role in sexual development.
Thalamus - serves as a relay station for almost all information that comes and goes to the cortex Fig. It plays a role in pain sensation, attention, alertness and memory. Basal ganglia - includes the caudate, putamen and globus pallidus. These nuclei work with the cerebellum to coordinate fine motions, such as fingertip movements. Limbic system - is the center of our emotions, learning, and memory. Included in this system are the cingulate gyri, hypothalamus, amygdala emotional reactions and hippocampus memory.
Cranial nerves The brain communicates with the body through the spinal cord and twelve pairs of cranial nerves Fig. Ten of the twelve pairs of cranial nerves that control hearing, eye movement, facial sensations, taste, swallowing and movement of the face, neck, shoulder No. Name Function and tongue muscles originate in the brainstem. The I olfactory smell cranial nerves for smell and vision originate in the II optic sight cerebrum.
III oculomotor moves eye, pupil IV trochlear moves eye V trigeminal face sensation Meninges VI abducens moves eye The brain and spinal cord are covered and protected by VII facial moves face, salivate three layers of tissue called meninges. X vagus heart rate, digestion XI accessory moves head XII hypoglossal moves tongue The dura mater is a strong, thick membrane that closely lines the inside of the skull; its two layers, the Figure 6. The Roman numeral, name, and main function of periosteal and meningeal dura, are fused and separate the twelve cranial nerves.
The dura creates little folds or compartments. There are two special dural folds, the falx and the tentorium. The falx separates the right and left hemispheres of the brain and the tentorium separates the cerebrum from the cerebellum. The arachnoid mater is a thin, web-like membrane that covers the entire brain.
The arachnoid is made of elastic tissue. The space between the dura and arachnoid membranes is called the subdural space. The pia mater hugs the surface of the brain following its folds and grooves. The pia mater has many blood vessels that reach deep into the brain. The space between the arachnoid and pia is called the subarachnoid space. It is here where the cerebrospinal fluid bathes and cushions the brain. Ventricles and cerebrospinal fluid The brain has hollow fluid-filled cavities called ventricles Fig.
Inside the ventricles is a ribbon-like structure called the choroid plexus that makes clear colorless Figure 7. CSF is produced inside the ventricles deep within the brain. CSF flows within and around cord and then outside to the subarachnoid space. Common sites of obstruction: 1 foramen of Monro, 2 This circulating fluid is constantly being absorbed and aqueduct of Sylvius, and 3 obex.
There are two ventricles deep within the cerebral hemispheres called the lateral ventricles. They both connect with the third ventricle through a separate opening called the foramen of Monro. The third ventricle connects with the fourth ventricle through a long narrow tube called the aqueduct of Sylvius.
From the fourth ventricle, CSF flows into the subarachnoid space where it bathes and cushions the brain. CSF is recycled or absorbed by special structures in the superior sagittal sinus called arachnoid villi. A balance is maintained between the amount of CSF that is absorbed and the amount that is produced. A disruption or blockage in the system can cause a build up of CSF, which can cause enlargement of the ventricles hydrocephalus or cause a collection of fluid in the spinal cord syringomyelia.
Blood supply Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries Fig. The internal carotid arteries supply most of the cerebrum. The vertebral arteries supply the cerebellum, brainstem, and the underside of the cerebrum. After passing through the skull, the right and left vertebral arteries join together to form the basilar artery.
The communication between the internal carotid and vertebral-basilar Figure 8. The common carotid artery courses up the neck and divides into the internal and external carotid arteries. The two systems connect at the Willis and prevent brain damage. Circle of Willis green circle. Usually arteries and veins run together as they supply and drain specific areas of the body. So one would think there would be a pair of vertebral veins and internal carotid veins.
However, this is not the case. The major vein collectors are integrated into the dura to form venous sinuses Fig. The venous sinuses collect the blood from the brain and pass it to the internal jugular veins. The superior and inferior sagittal sinuses drain the cerebrum, the cavernous sinuses drains the anterior skull base. All sinuses eventually drain to the sigmoid sinuses, which exit the skull as the jugular veins.
The two jugular veins are the only drainage of the brain. Language In general, the left hemisphere of the brain is responsible for language and speech and is called the "dominant" hemisphere.
The right hemisphere plays a large part in interpreting visual information and spatial processing. In about one third of individuals who are left-handed, speech function may be located on the right side of the brain. Left- Figure 9. Top view of the circle of Willis. The internal handed individuals may need special testing to carotid and vertebral-basilar systems are joined by the determine if their speech center is on the left or anterior communicating and posterior communicating arteries.
Aphasia is a disturbance of language affecting production, comprehension, reading or writing, due to brain injury — most commonly from stroke or trauma. The type of aphasia depends on the brain area affected. If this area is damaged, one may have difficulty moving the tongue or facial muscles to produce the sounds of speech. The individual can still read and understand spoken language but has difficulty in speaking and writing i. Damage to this area causes Wernicke's aphasia.
The individual may speak in long sentences that have no meaning, add unnecessary words, and even create new words. They can make speech sounds, however Figure Three quarter view of the dural covering of the they have difficulty understanding speech and brain depicts the two major dural folds, the falx and are therefore unaware of their mistakes. Memory Memory is a complex process that includes three capacity is limited to about 7 items.
For phases: encoding deciding what information is example, it enables you to dial a phone number important , storing, and recalling.
0コメント