BIO 446L 1st Edition Lecture 15 Outline of Last Lecture I. Spinal Cord Injurya. ParalysisII. Somatic sensory pathwaysa. PNSCNSb. Sensory pathwaysc. Spinal nerve reflexIII. Autonomic Nervous Systema. Cranialb. Organizationi. Sympatheticii. Parasympatheticc. Sympathetici. Thoracolumbard. Parasympathetici. craniosacralOutline of Current Lecture I. Autonomic Nervous System contda. Parasympathetic continuedi. CraniosacralII. Special Senses—Visiona. Layersi. Fibrousii. Vasculariii. Nervousb. Fibrousi. Sclera and corneac. Vasculari. Cilliary bodyii. The iris and pupild. The lense. The vitreousf. Nervous layeri. retinaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureAutonomic Nervous System—Parasympathetic Continued- parasympathetic nervous system—craniosacralo pre ganglion—very long and myalinatedo post ganglion—very short and nonmyalinatedo Ach at pre ganglion—nicotinic receptoro Ach at post ganglion—muscarinic receptoro Not always inhibitory Ex: If stimulus is high blood pressure, parasympathetic will increase in order to slow heart rateo Raynard Disease Hyperactivity of sympathetic Constriction of blood vessels—no circulationo Hirschsprung’s Disease Parasympathetic affected Congenital—baby has it at birth Problem with migration of neural crest cells to parasympathetic ganglia atgut- Causes abdomen to disdendo Muscarine poison Affects muscarinic receptors- Causes constriction of air passage, overactive digestion (vomiting and diarrhea), etc.- Afferent stimuli detected by autonomic receptorso Pain, distension, blood pH, blood pressureo Autonomic reflexes-- Arterial baroreflex Baroreceptors in aortic arch and carotid artery- Detect changes in pressure and sends signal to medulla oblongatao Vagus nerve (incoming and outgoing info)- Responses sent out in parasympathetic and sympathetic, depending on pressure change signalo If bp is high, sympathetic will decrease and parasympathetic will increase Special Senses—Vision- Layerso Fibrous Sclera and cornea Sclera= white of eye, avascular, collagen type Io Vascular Choroid layer Pupil and iris, cilliary bodyo Nervous Retina Photoreceptor cells- Posterior cavityo Vitreous layer and posterior chamber- Anterior cavityo Posterior chamber and anterior chamber- Macula= greatest visual- Optic disk= no photoreceptors (a blind spot), leads to optic nerve- Fibrous layer—sclera and corneao Sclera—connective tissue layer, very firmo Corneasclera junction= where sclera and cornea come together Circulation of fluid in anterior chamber of anterior cavity Trabecular mesh—between anterior chamber and CSJ- Fluid flows and filters througho Cornea—6 layers A layer of nonkeratinized stratified squamous epithelia Stroma layers on each side of epithelial layer Dua’s layer (along with the other layers) help keep moisture levels regulated- Vascular layero cilliary body Cilliary muscles innervated by cranial nerve three in parasympathetic Zonular fibers extend from cilliary body Epithelium on cilliary body projects on to posterior chamber of anterior cavity- Folded, double layero Secretes proteins for zonular fiber- Loose connective tissueo Secretes aqueous humoro Goes to anterior chamber and drained by sclera MA—glaucoma- Poor circulation of aqueous humoro The iris (pupil) Dilator pupillae muscle- Myoepithelial, sympathetic, dilation Sphincter pupillae muscle- Parasympathetic, constricts pupils- The lenso Simple cuboidal layero Developing crystalline fiber layero MA: presbyopia—stiff lens, near vision becomes hardero MA: cataract—clouding of lens- The vitreouso Posterior chambero Fluid= vitreous humor More viscous than aqueous humoro Incoming light cornea (refracts light) moves through aqueous humor lens (refracts light) retina (light projected upside down and backwards)- Nervous layero Retina Many layers- See which cells are forming these layers Photoreceptor cells Bipolar cells- Contact ganglion of retina Ganglion cells- Axons merge out of retina and become optic
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