Transcript Brain
Brain Lizette Torres Mina Yanny Per. 3 Function of the Brain • The control network for the body’s functions and abilities • It is in charge of things your body needs to stay alive • Tells your body what to do Layers of the Meninges • • • • The Dura Mater The Arachnoid Mater The Pia Mater Bone is situated over the meninges followed by periosteum and skin Dura Mater ● ● ● ● Outermost, toughest, and most fibrous of the three membranes Covers the brain and spinal cord Responsible for keeping in the cerebrospinal fluid Has two layers ○The superficial: serves as the skull’s inner periosteum ○The deep layer called the meningeal layer which is the actual dura mater. Dura Mater Cont. • Opens at times into sinus cavities, which are located around the skull. • Home to meningeal veins. • It envelops arachnoid mater • Carries blood from the brain to the heart. The Arachnoid Mater • Middle Layer of the meninges so it is between the dura mater and pia mater • Envelops the brain • Sends processes into the longitudinal and transverse fissure • Surrounds nerves • Forms tubular sheaths for nerves Arachnoid Mater cont. The Pia Mater • Innermost layer of the meninges, closest to brain • Composed of fibrous tissue • Covered on its outer surface by flat cells thought to be impermeable to fluid. • Pierced by blood vessels that travel to brain and spinal cord • Protects central nervous system by containing the cerebrospinal fluid The Brain and its sections ● The brain weighs three pounds ● Has a texture as jelly ● The main parts of the brain are the cerebrum, cerebellum, brainstem, frontal lobe, parietal lobe, occipital lobe, and temporal lobe ● Difference from left and right ● The Neuron forest The Brains Parts Brain and sections cont. Cerebrum ● Largest part of the brain ● Associated with higher brain function such as thought and action ● For remembering, problem solving, thinking, feeling and movement ● Has outer layer called cortex, which is the brains wrinkly surface Brain and sections cont. Cerebellum ● Receives information from sensory systems, spinal cord, and and other parts of the brain ● Regulates motor movements Brainstem ● Regulates heart rate, breathing, sleeping, and eating. ● Leads to as the spinal cord Brain and sections cont. Frontal Lobe • Front part of brain • involved in reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe • involved in movement, orientation, recognition, perception of stimuli Occipital Lobe • involved in visual processing Brain and Sections cont. Temporal Lobe • involved with perception and recognition of auditory stimuli, memory, and speech Left & Right of brain • Left: controls movement on the body’s right side and has logic abilities • Right: controls movement on the body’s left side and more for creativity Neuron Forest • Where the work of the brain goes on in individual cells • Signals that form memories and thoughts move through a nerve cell as an electrical charge. Brain Development Ectoderm Neural Plate Prosencephalon Telencephalon Diencephalon Cerebral cortex Retina of the eye basal nuclei Thalamus Hypothalamus Mesencephalon Rhombencephalon Mesencephalon Metencephalon Myelencephalon Midbrain Superior colliculus inferior colliculus Pons Cerebellum Medulla Reflexes • Reflexes are an automatic response to a stimulus • maintain homeostasis • 2 types – Spinal reflexes – brain reflexes Spinal Reflex • response is mediated by neurons in the spinal cord • Action occurs without the awareness of brain – ex. Kneejerk Brain Reflexes • Reflexes mediated by the brainstem • brain receives information and generates a response • ex. movements of the eyes while reading this sentence Neurons • Nerve cell • transmit information • 3 types – motor neuron – sensory neuron – interneurons Sensory Neurons • Nerve cells that detect changes and send information • it may activate a motor neuron or another sensory one • Afferent neurons Motor Nerves • Efferent • They carry signals from the spinal cords to muscles • They produce movements interneurons • They create neural circuits to enable the communication between motor neurons or sensory neurons and the central nervous system Cranial Nerves ● There are 12 pairs of cranial nerves ● They emerge directly from the brain and the brain stem. ● They exchange information between the brain and the body parts ○ some bring information from sense organs and others control muscles Olfactory nerve • First cranial nerve • A sensory nerve • It carries the sensory information for smell • Capable of regeneration Optic Nerve • a sensory motor • Transmits visual information from the retina to the brain • ex . brightness perception, contrast Oculomotor Nerve • It is a motor nerve • It controls most of the eye’s movements – ex. maintaining the opening of an eye lid and pupil constriction Trochlear nerve • It is a motor nerve • It innervates a single muscle • the superior oblique muscle of the eye • It has the smallest number of axons Trigeminal nerve • it is a sensory and a motor nerve – sensation in the face – chewing and biting • divided in 3 branches – ophthalmic, maxillary and mandibular Abducens nerve • somatic efferent nerve • motor nerve • controls the movement of the lateral rectus muscle of the eye Facial nerve • • • • both motor and sensory nerves It emerges from the brain stem Responsible for facial expressions it also supplies sensation information – taste sensation vestibulocochlear nerve • It is a sensory nerve • it transmits sound and equilibrium information from inner ear to brain • it consists of cochlear nerve and vestibular nerve glossopharyngeal nerve • both sensory and motor nerve – carries afferent sensory and efferent motor information • several functions – receives general sensory fibers – receives special sensory fibers – receives visceral sensory fibers Vagus nerve • both motor and sensory nerve • it supplies motor parasympathetic fibers to all organs except adrenal glands • it controls few skeletal muscles Accessory nerve • motor nerve • provides information about the spinal cord, trapezius and other surrounding muscles. • provides muscle movement of the shoulders and surrounding neck. Hypoglossal nerve • it is a motor nerve • innervates movement of the tongue – controls movement required for speech, swallowing and food manipulation. Spinal Nerves • 31 pairs of spinal nerves • organized and divided into 4 regions – Cervical – Thoracic – Lumbar – Sacral • provide communication between body parts and cns • they split into 3-4 branches – Dorsal branch – Ventral branch – Visceral branch – Meningeal branch • 2 roots – posterior – anterior Cervical nerves • 8 pairs – C1 - C8 • emerge from corresponding vertebrae • they innervate the sternohyoid, sternothyroid and omohyoid muscles Thoracic nerves • 12 pairs – T1 - T12 • originate from corresponding vertebra • they communicate with parts of chest or thorax and abdomen Lumbar nerves • 5 pairs – L1 - L5 • emerge from lumbar vertebrae • they supply many muscles – ex. Gluteus medius muscle and gluteus minimus Sacral nerves • 5 pairs – S1 - S5 • start inside the vertebral column and exit the sacrum • they supply the hip, thigh and foot Works Cited Patricia Anne Kinser, “Brain Structures and Their Functions.” Serendip Studio. Paul Grobstein, 5 September 2012. Web. 21 April 2015. <www.serendip.bryanmawer.edu> Alzheimer’s Association, “3 Main Parts of the Brain.” Alzheimer’s Association. 2011. Web. 19 April 2015. <www.alz.org/braintour> “Arachnoid Trabeculae.” Encyclopedia Britannica. 9 September 2010. Web. 19 April, 2015. <www.en.wikipedia.org/arachnoidtrabeculae> Michelle Watnick, ”Nervous System II.” Hole’s Human Anatomy and Physiology. Fran Schreiber, 2007. Book. 18 April 2015.