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The Central Nervous System. CNS. Meninges of the Brain. Dura Mater (HARD MOTHER) - outer layer, strong white fibrous tissue. Arachnoid membrane (SPIDER WEB) - middle layer, cobweb like layer. Pia Mater (SOFT MOTHER)-inner layer, adheres to the brain, translucent. Divisions of Meninges.
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Meninges of the Brain • Dura Mater (HARD MOTHER) - outer layer, strong white fibrous tissue. • Arachnoid membrane (SPIDER WEB) - middle layer, cobweb like layer. • Pia Mater (SOFT MOTHER)-inner layer, adheres to the brain, translucent.
Divisions of Meninges Falx cerebri- parts right and left cerebral hemispheres Sinuses within the dura function as venus reservoirs Pia mater contains blood vessels that surround brain Falx cerebri Falx cerebri
Did you know? Menigitis- inflammation of the meniges caused by bacteria, viral or fungal infections. Subdural Hematoma- large blood clot found in under the dura mater. Usually sign of trauma.
Cerebral Spinal fluid • CSF- provides a cushion of protection around brain spinal cord. • Ventricles- 4 fluid filled spaces in the brain. • 1st & 2nd (2 lateral), 3rd and 4th (very tiny) • CSF is formed in the choroid plexuses then circulated via the ventricles
The Brain Stem Brain Stem(vital centers) • Medulla Oblongata- controls heart rate, blood pressure, breathing • Landmarks- olives & pyramids • Pons- helps control vital functions
The MidBrain Midbrain- connects brain stem and cerebrum via the cerebral peduncles Corpora quadrigemina (“body of four twins”) is the inferior and superior colliculi. Inferior colliculi functions as auditory processing center. Superior colliculi function as visual processing center. Red nucleus and substantianigri(black matter) function in motor control., secretes dopamine.
The Brain Cerebellum • Controls skilled muscle movements, posture and balance. • Is connected to thalamus and motor cortex areas of the cerebrum.
Hypothalamus Connects info from nervous and endocrine to maintain homeostatsis. Regulates appetite and feelings of satisfaction. Mind-body link (psychosomatic affect). Temperature control site Diencephalon “between-brain”
Thalamus detects mild pain and temperature sensation determines whether something is pleasant Relays sensory info to cerebrum Optic chiasma-where optic nerve cross before entering the brain Pineal gland-secretes melatonin to regulate sleep. Diencephalon
The Cerebrum Gyrus (bulge) Sulcus (crevice)
The Cerebrum Cerebrum • Cerebral cortex- gray matter on the outside of the cerebrum • Responsible for conscious thought • Memory • Awareness • language • reasoning.
Cerebral plasticity- regions can vary in their functions between different individuals.
Regions of the Cerebrum Corpus callosum Cingulate gyrus Hypothalamic nuceli Anterior thalamic nuclei • Corpus Callosum-connects the right and left hemispheres • Limbic system- controls emotions, anger, sorrow and pleasure. • Hippocampus- found in the limbic system and associated with short term memory • Amygdala- helps decode Fornix Olfactory tract Mammillary bodies Amygdala Parahippocampal gyrus Hippocampus
Regions of the Cerebrum Reticular Activating system-when stimulated causes consciousness • REM- rapid eye movement sleep, dreaming • SWS- slow wave sleep, no dreaming
Image of Brain Homunculus • “little man” represented in each hemisphere of the brain, depicts amount of sensory receptors in certain areas
Disorders of the Brain Stroke (Cerebrovascular accident CVA) • Usually because of a clot there is a cessation of blood to the brain and the region is starved of oxygen. • Hemiplegia- paralysis on one side of the body. Huntington disease • Involuntary movements, dementia and death Creutzfeldt-Jakob • Human mad cow disease. A prion causes protein denaturization in the brain. Seizures • sudden burst of neuron activity. Epilepsy is chronic seizure, normally idiopathic.
The Spinal Cord • Located within the spinal cavity along with the meninges, cerebrospinal fluid, adipose tissue and blood vessels
The Spinal Column • Dorsal nerve root • Carry sensory information to the spinal cord, afferent pathways • Cell bodies of these unipolar neurons make up a small area of gray matter called the dorsal root ganglion • Ventral nerve root • Carries motor information out of spinal cord, efferent pathways • Cell bodies of these mulitpolar neurons compose the inner core of gray matter • Spinal Nerve • Dorsal and Ventral join together to form this single nerve
The Spinal Cord • Ascending Tracts • Conduct sensory impulses up to the brain • Descending tracts • Conduct motor impulses down from the brain
Nerve Repair PNS • Nerve damage caused by trauma can sometime be repaired by regrowth of the axon • Neurons can never replicate themselves • There is evidence that shows new neurons can grow out of adult stem cells in the spinal cord CNS