A&P Chapter 14 - Lecture notes 11 PDF

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Biol 2401 with Prof. Vasefi...

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Brain: 2% of body weight, consumes 20% of oxygen & glucose used at rest Protective Brain Coverings: cranium, cranial meninges, cerebrospinal fluid A. Cranial Meninges: continuous with spinal meninges 1. Dura Mater (outermost) a. Periosteal: fused to periosteum to the cranial bones b. Meningeal 2. Arachnoid mater  Membrane covers the brain; providing a smooth surface that does not follow the brain’s underlying folds 3. Pia mater  Sticks to surface of the brain, anchored by the processes of astrocytes B. Cerebrospinal Fluid: protects brain, transports substances b/t blood & nervous tissues o Most cerebrospinal fluid in hollow cavities, brain ventricles i. 2 lateral ventricles, 3rd ventricle, 4th ventricle o formed in choroid plexuses of 2 lateral ventricles o ependymal cells filter fluid from brain & secrete it into ventricles o created by tight junctions, separates blood from bone tissue o protects brain from pathogens & taking in blood Brain:  receives sensory info, integrates new & stored info, sends motor output  perception, memory, emotion & behavior  4 major divisions: brain stem, cerebellum, diencephalon, cerebrum A. Brainstem: medulla oblongata, pons, midbrain 1. Medulla Oblongata:  sensory: touch, taste, hearing, equilibrium, proprioception  integrative: regulates heart rate, stroke volume of heart, diameter of blood vessels o ventilation rate  motor: motor output to skeletal muscles of limbs & trunk, passes through MO o motor tracks cross from 1 side of MO to other 2. Pons: responsible for regulation of ventilation rate w/t medulla oblongata  communication b/t 2 sides of cerebellum & cerebellum & rest of brain 3. Midbrain: connection b/t cerebrum & spinal cord  sensory: hearing  motor: eye muscles B. Cerebellum: 10% of brain mass, 50% of neurons in brain o regulates balance & posture, creating skilled voluntary movements C. Diencephalon: thalamus, hypothalamus, epithalamus 1. Thalamus: relays sensory info from brain stem to cerebrum  communication b/t cerebellum & cerebrum 2. Hypothalamus: part of nervous & endocrine system,  controls ANS, makes hormones, major regulator of homeostasis

regulates body temp., biological clock, eating, drinking, emotions & behavior 3. Epithalamus:  pineal gland: involved in regulation of biological clock by releasing melatonin o works w/t hypothalamus  habenular nuclei: involved in smell D. Cerebrum: largest part of brain, 2 cerebral hemispheres Alexandria Toledo Anatomy of Cerebrum:  corpus callosum: connects hemispheres  cerebral cortex: superficial layer of gray matter  cerebral white matter: deep layer Fissures: deep valleys dividing lobes Gray matter: cell bodies, dendrites, & neuroglia; Function: integration White matter: myelinated & unmyelinated axons; Function: communication Tracts: bundle of axons in CNS Nerves: bundle of axons outside CNS Gyri: raised ridges Sulci: shallow valleys b/t gyri 4 Lobes of Cerebral Hemisphere: frontal, parietal, temporal, occipital Babal Nuclei: masses of gray matter in white matter of cerebral hemispheres  regulate body movements & muscle tone, suppresses unwanted movements Limbic System: ring of structures encircling brain stem & corpus callosum  generates emotions, involved in olfaction & memory Function of Cerebral Cortex:  different sensory, motor & integration signals processed in diff. regions of cerebral cortex  sensory: sensory areas receive sensory input, involved in perception, o sensory input from 1 side of body processed in opposite cerebral hemisphere o primary somatosensory area  specific areas receive sensory input from specific body parts  some body parts have larger regions of somatosensory areas  motor: motor areas send motor input, involved in movement o primary motor area  plans & initiates voluntary body movements  specific areas send motor output to specific body parts  some body parts get larger somatic motor area regions  integrative: association areas, integration o complex mental functioning: memory, emotions, reasoning Hemispheric Lateralization: mental functions primarily but not entirely performed in 1 hemisphere A. Left Hemisphere: reasoning, numerical skills, language B. Right Hemisphere: musical & artistic skills, spatial & pattern perception  recognition of faces & emotional content of language 

Reflex Arc: pathway that followed by nervous impulse to produce reflex

1. Arrival of stimulus and activation of receptor 2. Activation of a sensory neuron 3. Information processing in CNS 4. Activation of a motor neuron 5. Response by peripheral effector Vagus nerves: important in parasympathetic nervous sytem; innervates heart, lungs, and GI tract...