In cerebrum between the division of two hemispheres there is a division known as diencephalon. Diencephalon has structures like thalamus, hypothalamus, subthalamus and the epithalamus. The difference between thalamus and hypothalamus is the difference of their functions and their location within the brain. Basic function of thalamus is to regulate sensory motor activities, whereas hypothalamus is mainly responsible for releasing, producing and inhibiting several hormones in the body which produces other hormones.
There are a lot more differences between both of them. Brain has sensory nerves which pass the signal to the thalamus as soon as something happens and then the thalamus gives a reaction and sends further signals to the cerebral cortex. Thalamus itself is a complex structure and constituted by two ends anterior and posterior poles. Also has four surfaces, those are Thalamus is the largest subdivision in diencephalon consisting of nuclei in each side of forebrain or cerebrum. It is located in the centre of the brain, lying on top of the brainstem.
It surrounds the third ventricle within the brain. Thalamus and hypothalamus are two masses of the gray matter made up of small nuclei. Also, they are two components of the diencephalon , which is a division of the forebrain. What is Thalamus — Definition, Anatomy, Function 2. What is Hypothalamus — Definition, Anatomy, Function 3.
Thalamus is a large mass of the gray matter. It forms the dorsal part of the diencephalon and is located between the cerebral cortex and the midbrain. Also, it is a midline symmetrical structure with two halves called lobules located in each brain hemisphere. Further, the medial surface of the thalamus forms the upper part of the lateral wall of the third ventricle. And, the lateral part of the thalamus is the neothalamus , including the lateral nuclei, the pulvinar, and the medial and lateral geniculate nuclei.
Figure 1: Thalamus and Hypothalamus. Moreover , the stratum zonale is the white matter of the thalamus, covering the dorsal surface, and the external and internal medullary laminae. Besides, t he external lamina covers the lateral surface, and the internal lamina divides the nuclei into anterior, medial and lateral groups.
Concerning the functions, the main function of the thalamus is to serve as a relay station, relaying information between different subcortical regions and the cerebral cortex. Dec 1, The thalamus, hypothalamus and pineal gland are a part of diencephalon. Related questions What are the symptoms of alcohol poisoning?
What are the long-term and short-term effects of What kind of anti-inflammatory medication is safe to take during the first trimester of pregnancy? How does the anti-inflammatory response affect a wound? What induces the inflammatory response? These areas are defined by distinct clusters of neurons.
The thalamus derives its blood supply from four arteries including the polar artery posterior communicating artery , paramedian thalamic-subthalamic arteries, inferolateral thalamogeniculate arteries, and posterior medial and lateral choroidal arteries.
These are all derived from the vertebrobasilar arterial system except the polar artery. The thalamus is connected to the hippocampus via the mammillothalamic tract. The Nuclei of the Thalamus : The graphic details the various nuclei of the thalamus. The thalamus has multiple functions, serving as a sort of switchboard of information.
It is generally believed to act as a relay between a variety of subcortical areas and the cerebral cortex. In particular, every sensory system with the exception of the olfactory system has a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area. For the visual system, for example, inputs from the retina are sent to the lateral geniculate nucleus of the thalamus, which in turn projects to the primary visual cortex in the occipital lobe.
The thalamus is believed to both process and relay sensory information. Each of the primary sensory relay areas receives strong back projections from the cerebral cortex. Similarly, the medial geniculate nucleus acts as a key auditory relay between the inferior colliculus of the midbrain and the primary auditory cortex. The ventral posterior nucleus is a key somatosensory relay, which sends touch and proprioceptive information to the primary somatosensory cortex. Fatal familial insomnia is a hereditary prion disease characterized by degeneration of the thalamus and leading to a gradual progression to a state of total insomnia that is eventually fatal.
The hypothalamus is located below the thalamus just above the brain stem. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is roughly the size of an almond. The location of hypothalamus and pituitary : At center, hypothalamus is located just superior to the pituitary, with which it closely interacts. Location of the hypothalamus : This is the location of the human hypothalamus in relation to the thalamus, pituitary gland, sella turcica, and optic chiasm.
One of the most important functions of the hypothalamus is linking the nervous system to the endocrine system via the pituitary gland hypophysis. The hypothalamus contains thyrotropin-releasing hormone, gonadotropin-releasing hormone, growth hormone-releasing hormone, corticotropin-releasing hormone, somatostatin, and dopamine, as well as vasopressin and oxytocin. These hormones are released into the bloodstream and target other organ systems, most notably the pituitary.
The hypothalamus affects the endocrine system and governs emotional behavior such as anger and sexual activity. Most of the hypothalamic hormones generated are distributed to the pituitary via the hypophyseal portal system.
The hypothalamus maintains homeostasis, including the regulation of blood pressure, heart rate, and temperature. The hypothalamus coordinates hormonal and behavioral circadian rhythms, complex patterns of neuroendocrine outputs, complex homeostatic mechanisms, and important behaviors. It must therefore respond to many different signals, some of which are generated externally and some internally.
The hypothalamus is thus richly connected with many parts of the central nervous system, including the brainstem, reticular formation and autonomic zones, and the limbic forebrain particularly the amygdala, septum, diagonal band of Broca, olfactory bulbs, and cerebral cortex.
The hypothalamus can sample the blood composition at the subfornical organ and the organum vasculosum of the lamina terminalis. This is important for the uptake of circulating hormones and to determine concentration of substances in the blood. The hypothalamus functions as a type of thermostat for the body.
It sets a desired body temperature and stimulates either heat production and retention to raise the blood temperature to a higher level, or sweating and vasodilation to cool the blood to a lower temperature.
All fevers result from a raised setting in the hypothalamus; elevated body temperatures due to any other cause are classified as hyperthermia. Rarely, direct damage to the hypothalamus such as from a stroke causes a fever; this is sometimes called a hypothalamic fever.
However, such damage more commonly causes abnormally low body temperatures.
0コメント