Ch 14 A&P Brain And Cranial Nerves

Where is 98% of the body's neural tissue? The brain. cerebrum the anterior and largest part of the brain, consisting of two halves or hemispheres What do the paired cerebral hemispheres control? Conscious thoughts, sensations, intellect, memory, and complex movement all originate in the cerebrum What are some landmarks of the cerebral cortex? gyri, sulci, fissures gyrus a convolution sulcus a groove or fissure, esp. a fissure between two convolutions of the brain, shallower than fissure fissure a natural division or groove in an organ, as in the brain. cerebellum a large portion of the brain, in back of and below the cerebrum and consisting of two lateral lobes and a central lobe - btwn occ lobe and brain stem What does the cerebellum do? coordinate voluntary movements, posture, and balance diencephalon thalamus (right & left) and hypothalamus, the posterior section of the forebrain What does the diencephalon contain? relay and processing centers hypothalamus between the thalamus and midbrain What does the hypothalamus do? Controls emotions, autonomic function, hormone production, apetite, body temperature What does the brain stem include? Midbrain, pons (bridge), medulla oblongata Midbrain Has nuclei that process visual and auditory information and control reflexes triggered by these stimuli pons (bridge) nuclei involved with somatic and visceral motor control medulla oblongata sensory information to the thalamus and other places, contains major centers that regulate autonomic functs ( What is the transitional area betweent he diencephalon and the spinal cord? Midbrain *Cerebrum Conscious thought processes, intellectual functions, memory storage and processing, conscious and subcon. regulation of skeletal muscle contractions *Thalamus relay and precessing centers for sensory information *Hypothalamus Centers controlling emotions, autonomic functions, and hormone production *Mesencephalon (middbrain) processing of visual and auditory data, gerneration of reflexive somatic motor responses, maintenance of consciousness *Pons relays sensory information to cerebellum and thalamus, subconscious somatic and visceral motor centers *Medulla oblongata relays sensory information to thalamus and to other portions of the brain stem, autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities) *Cerebellum coordinates complex somatic motor patterns, adjusts output of other somatic motor centers in brain and spinal cord What are the ventricles of the brain? Large lateral ventricle (1&2), diencephalon ventricle (3), and pons and cerebellum ventricle (4) Central canal center of the spinal cord, a continuation of the large ventricle What are 1 & 2? Large lateral ventricle - cerebrohemisphere ventricles full of CSF, runs into 3 What provides protection and support for the brain? The cranial meninges Cranial meninges continuous with spinal meninges - cranial dura mater, arachnoid mater, pira mater Cranial pia mater contains blood vessles, brain tissue itself doesn't have blood Functions of the cranial meninges 1: Tough fibrous extensions of the dura mater celled dura folds act like safety belts that hold the brain in position. Functions of the cranial meninges 2: The cerebrospinal fluid in the subarachnoid space acts like an airbag that cusions against sudden jolts and shocks Cerebrospinal Fluid & function Surrounds and bathes the exposed surfaces of the CNS - Fuctions: Cushioning, supporting, transport nutrients, chem. messenger, waste products What kind of chemicals does the CSF transport? neurotransmitters and hormones Circulation of CSF Choroid plexus > ventricles > central canal of spinal cord > subarachnoid space surrounding the spinal cord Some areas of the CSF and blood supply are together so they can...? exchange nutrients and wastes How does the brain get its blood supply? Major arteries (internal carotid arteries and the vertebral arteries) and internal jugular veins (main vein, drains brain) Why is blood not in the TISSUE of the brain? Blood brain barrier blood brain barrier neural tissure in the CNS is isolated due to astrocytes (support), tight juntions, only lipid-soluble compounds can diffuse Why is transport across the BBB selective and directional? neurotransmitter entry from the bloodstream could result in the uncontrolled stimulation of neurons throughout the brain WBC aren't in the brain to act protect it so what does? microglia *Exception to BBB 1: Portions of the hypothalamus – monitors temperature of blood *Exception to BBB 2: Posterior lobe of the pituitary gland – secrete hormones into the blood *Exception to BBB 3: Capillaries in the pineal gland – secrete melatonin *Exception to BBB 4: Capillaries at the choroid plexus – CFS gets rid of waste here medulla oblongata continuous with the spinal cord, communication center, coordinates autonomic reflexes, control visceral functions The pons (bridge) Links and controls 4 groups of components 1st component controlled by pons sensory and motor nuclei of cranial nerves 2nd component controlled by pons nuclei involved with the control of respiration - triggered by the level of CO2 (carbon dioxide) in blood 3rd component controlled by pons nuclei and tracts that process and relay information and heading to of from the cerebellum - pons right in front of cerebellum, motor information sent from cerebellum to pons to muscles cerebellum automatic processing center 2 primary functions of cerebellum 1) adjusting the postural muscles of the body, muscle tone 2) programming and fine-tuning movements, atheletes build up nerve pathways mesencephalon midbrain, contains corpora quadrigemina - nuclei process visual and auditory sensations - ties them together and reflexes are involved diencephalon thal & hypo, conscious and unconscious sensory information and motor commands Pineal gland (pineal body, epiphysis) makes melatonin, biological clock thalamus final relay point for ascending sensory information, acts as a filter (tons of information, don't need to be conscious of of everything) functions of hypothalamus subconscious control of skeletal muscle contractions, control autonomic function, production of emotions and behavioral drives, regulation of body temperature Where does the fissure end? at the top of the corpus collosum corpus callosum made of fibers (nervous tissue) two cerebrohemispheres communicate through here What is the entire part of the brain with the gyri? cerebrum, ends at corpus callosum = gray matter, diencephalon = white matter Functions of limbic system establish emotional states, links conscious with unconscious, facilitates memory storage and retrieval amygdaloid body interface btwn limbic system, cerebrum, and various sensory systems - ties in different systems hippocampus important in learning, especially in the sotrage and retrieval of new long term memories What's the largest region of the brain? cerebrum, contains gray and white matter cerebral cortex a blanket of neural cortex - most superficial, gyri, longitudinal fissure, corupus callosum, central sulcus longitudinal fissure seperates 2 hemispheres central sulcus divides the pregyrus and postgyrus cerebral lobes each cerebral hemisphere receives sensory information, the 2 hemispheres have different functions, the assignment of a specific function to a specific region of the cerbral cortex is not exact integrative centers direct extremely complex motor activities, complex analytical functions, general interpretive area and the speech center general interpretive area receives information from all the sensory association areas, personality may be related to how you interpret those senses, left hemisphere the speech center lies along the edge of the premotor cortex, regulates the patterns of breathing and vocalization hemispheric lateralization functions that are not ordinarily performed by the opposite hemisphere, left hemisphere, right hemisphere, left/right brained cranial nerves PNS components, twelves pairs, number corresponds to position Types of cranial nerves sensory, special sensory, motor, mixed olfactory nerves I special sensory, sense of smell optic nerves II special sensory, eyes oculomotor nerves III motor nerves, innervates four of the six extra-ocular muscles trochlear nerves IV motor nerves, helps in looking down abducens nerves VI motor nerves, makes the eye look side to side trigeminal nerves V mixes, provides somatic sensory info from the head and face, has 3 branches: ophthalmic branch, maxillary branch, mandibular branch facial nerves VII mixed, provides deep pressure sensations, control the superficial muscles of the scalp and face, bells palsy effects cranial nerve VII vestibulocochlear nerves VIII special sensory, balance from inner ear and equilibrium, hearing from cochlea, provides sense of hearing glossopharyngeal nerves IX mixed to head and neck, innervate the tongue (speech) and pharynx (swallowing), provide taste sensations (sensory) muscles involved with swallowing vagus nerves X mixed, provide somatic sensory information about 6 things, controls breathing and heart rate Vagus nerves provide somatic sensory info about: external acoustic canal, diaphragm, pharyngeal taste receptors, esophagus, repiratory tract, abdominal viscera accessory (spinal) nerves XI motor to muscles of the neck and upper back, voluntary swallowing muscles, SCM and trapexius muscles hypoglossal nerves XII motor, tongue movements