Sierra Acai Company
Sierra Acai Company
Open 7 Days a Week
MonaVie Independent Distributor
Distributor Training
Shop Online
Enroll Now
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
Friends
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
14-September-2008 18:02:37 - Periaqueductal gray Brain: Periaqueductal gray Section through superior colliculus showing path of oculomotor nerve. Periaqueductal gray is the gray area just peripheral to the cerebral aqueduct. Coronal section through mid-brain. 1. Corpora quadrigemina. 2. Cerebral aqueduct. 3. Central gray stratum. 4. Interpeduncular space. 5. Sulcus lateralis. 6. Substantia nigra. 7. Red nucleus of tegmentum. 8. Oculomotor nerve, with 8', its nucleus of origin. a. Lemniscus in blue with a' the medial lemniscus and a the lateral lemniscus. b. Medial longitudinal fasciculus. c. Raphé. d. Temporopontine fibers. e. Portion of medial lemniscus, which runs to the lentiform nucleus and insula. f. Cerebrospinal fibers. g. Frontopontine fibers. Latin s. grisea centralis Gray's subject #188 806 NeuroNames hier-501 MeSH Periaqueductal+Gray Dorlands/Elsevier s_27/12766787 Periaqueductal gray PAG; also called the central gray is the midbrain grey matter that is located around the cerebral aqueduct within the midbrain. It plays a role in the descending modulation of pain and in defensive behaviour. The ascending pain and temperature fibers of the spinothalamic tract also send information to the PAG via the spinomesencephalic tract. The spinomesencephalic tract is so-named because the fibers originate in the spine and terminate in the mesencephalon, another name for the midbrain, which is the part of the brain in which the PAG resides. Contents 1 Role in Analgesia 2 Role in defensive behavior 3 Role in reproductive behavior 4 Additional images 5 External links Role in Analgesia Stimulation of the periaqueductal gray matter of the midbrain activates enkephalin releasing neurons that project to the raphe nuclei in the brainstem. 5-HT serotonin released from the raphe nuclei descends to the dorsal horn of the spinal cord where it forms excitatory connections with the inhibitory interneurons located in Laminae II aka the substantia gelatinosa. When activated, these interneurons release either enkephalin or dynorphin endogenous opioid neurotransmitters which bind to mu opioid receptors on the axons of incoming C and A-delta fibers carrying pain signals from nociceptors activated in the periphery. The activation of the mu-opioid receptor inhibits the release of substance P from these incoming first order neurons and in turn inhibits the activation of the second order neuron that is responsible for transmitting the pain signal up the spinothalamic tract to the ventroposteriolateral nucleus VPL of the thalamus. The nociceptive signal was inhibited before it was able to reach the cortical areas that interpret the signal as pain such as the anterior cingulate. This is sometimes referred to as the Gate control theory of pain and is supported by the fact that electrical stimulation of the PAG results in immediate and profound analgesia. Three known kinds of opioid receptors have been identified- mu, kappa, and delta. Synthetic opioid and opioid-derivative drugs activate these receptors possibly by acting on the PAG directly, where a dense amount of these receptors are expressed to produce analgesia- including heroin, morphine, vicodin, and similar pain modulating compounds. Role in defensive behavior Stimulation of the dorsal and lateral aspects of the PAG in the rat can provoke defensive responses characterised by freezing immobility, running, jumping, tachycardia and increases in blood pressure and muscle tonus. Conversely, stimulation of the caudal ventrolateral PAG can result in an immobile, relaxed posture known as quiescence, while its inhibition leads to increased locomotor activity. Lesions of the caudal ventrolateral PAG can greatly reduce conditioned freezing, while lesions of the dorsal aspect can reduce innate defensive behavior, virtually taming the animal. Role in reproductive behavior Neurons of the PAG are excited by endorphins and by opiate analgesics. It also plays a role in female copulatory behavior see Lordosis behavior via a pathway from the ventromedial nucleus of the hypothalamus. Additional images Schematic representation of the chief ganglionic categories I to V. Transverse section of mid-brain at level of inferior colliculi. Transverse section of mid-brain at level of superior colliculi. External links BrainMaps at UCDavis Periaqueductal gray v d e Brain: mesencephalon midbrain Tectum Dorsal Corpora quadrigemina: Inferior colliculi Brachium of inferior colliculus, Superior colliculi Brachium of superior colliculus Subcommissural organ Pretectum Peduncle Ventral Peduncle tegmentum Periaqueductal gray Cerebral aqueduct, Dorsal raphe nucleus Ventral tegmentum Pedunculopontine nucleus Red nucleus Rubrospinal tract, Rubro-olivary tract MLF riMLF lemnisci Medial, Lateral cranial nuclei: GSA V: Mesencephalic - GSE III: Oculomotor, IV: Trochlear - GVE III: Edinger-Westphal Interstitial cell of Cajal Superior cerebellar peduncles Decussation of superior cerebellar peduncle Peduncle base Substantia nigra Pars compacta, Pars reticulata Cerebral crus: Corticospinal tract - Corticobulbar tract - Corticopontine tract/Frontopontine fibers/Temporopontine fibers Interpeduncular fossa Retrieved from http://en..org/wiki/Periaqueductal_gray Categories: Brainstem | Neuroanatomy Views Article Discussion this page History Personal tools Log in / create account Navigation Main page Contents Featured content Current events Random article Search Go Search Interaction Community portal Recent changes Contact Donate to Help Toolbox What links here Related changes Upload file Special pages Printable version Permanent link Cite this page Languages Deutsch Español Nederlands Polski 中文 This page was last modified on 14 June 2008, at 15:51
39 Reasons to Drink Acai Juice Every Day
What is MonaVie - Watch the 8-minute video
Discovering MonaVie Video
The Power of You Video
Effects of MonaVie Active on Antioxidant Capacity in Humans
Log into your Wholesale MonaVie Account
So many of us do not eat a balanced diet, get enough sleep, have too much stress, or are impacted with toxins and pollutants. Drinking 2 ounces of MonaVie twice a day will help your body detoxify as well as build your immune system. Its the smartest thing you can do for yourself, so start today. Buying MonaVie through our company guarantees you support 7 days a week and, if you would like to share MonaVie with your family and friends we will guide you from start to finish.
1. Click on Enroll Now (30 - 55% off retail price)
2. Pay $39 for your Wholesale ID number.
3. NO minimum order required.
4. MonaVie is delivered to your door in 3 to 5 days.