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Kharkov National Medical University LECTURE for dentistry students Department of Histology, cytology and embryology SENSORY System CARDIOVASCULAR System SENSORY System Organ of Olfaction (Smell) is located in the nasal mucosa Consists of: 1. Supporting cells 2. Basal cells (renewal) 3. Olfactory cells having cilia and axons forming nerve The Eye. Visual organ * fibrous tunic the wall contains vascular uvea neural retina eyeball contents: lens, vitreous body, aqueous humor Sclera Uvea Retina Cornea Central Fovea Pupil Lens Iris Ciliary Body Optic Nerve I. Fibrous tunic has two main portions sclera: dense regular connective tissue cornea: thicker, 5 layers: outer corneal epithelium Bowman's membrane stroma Membrane of Descemet endothelium Cornea contains free nerve endings permeable, avascular, transparent outer II. Uvea – loose con.t. 3 parts: • Choroid is nutritive • Ciliary body keeps lens • Iris is diaphragm with pupil Sclera Choroid Retina Cornea Central Fovea Pupil Lens Iris Ciliary Body Optic Nerve LIMBUS Iris • Iris constrictor, dilator muscles regulate pupil • Ciliary body muscles relax the lens • Anterior chamber • Posterior chamber = nutritive fluid • Lens Ciliary body Sclera Choroid Retina Cornea Vitreous Body Pupil Is dioptric fluid Lens Iris Ciliary Body III. Retina • 10 layers of neurons and their processes • chain of 3 neurons: layer of visual cells (rods and cones) – outer nuclear, layer of bipolar cells – inner nuclear, layer of ganglionic cells. pigment cells (outermost) 2 sheaths 9 layers of neurons and processes Sclera Choroid Retina Cornea Ora serrata Pupil Lens Iris Ciliary Body Optic Nerve Vitreous Body Retina Choroid Sclera Muscles III 10 9 8 7 II 6 5 I 4 3 2 The way of light waves • • • • • • • Through the cornea Anterior chamber Pupil Posterior chamber Lens Vitreous body Through all layers of the retina to rods and cones Vitreous body Ganglionic layer Ganglionic l. Inner Innernuclear nuc. layer Outer nuclear Outer nu. layer Rods cones Choroid Sclera Sclera Vitreous body I. Retina II. Cornea photosensitive apparatus dioptric apparatus Cham ber Central Fovea (yellow m.) Lens III.Iris IrisCiliary body accommodative apparatus Optic Nerve (blind m.) Organ of Hearing and Equilibrium • Ear contains: • External ear • Middle ear • Inner ear = labyrinth External Ear Middle Ear Middle Ear. Auditory (Eustachian) tube leads to nasopharynx auditory tube Inner ear = labyrinth is located in the temporal bone contains cochlea (organ of hearing), vestibule and semicircular canals, (organ of equilibrium) Inner Ear Vestibule, semicircular canals, cochlea Inner Ear • Bony labyrinth is filled with perilymph • Contains: • Membranous labyrinth is filled with endolymph Section of the inner ear C SC V Cochlea (C), vestibule (V) the semicircular canal (SC). Cochlea is spiral SV One section of the cochlea spiral canal VM CD Limbus OC Sl n S lig BM ST Vestibular membrane (VM) and basilar membrane (BM) divide canal into scala vestibuli (SV), cochlear duct (CD) and scala tympani (ST). m SV VM CD BM ST Scala vestibuli ends with oval window, scala tympani with round, lead to middle ear cochlear duct ME Cochlear duct CD VAS Three angular, three walls VM CD OC VAS – stria vascularis Limbus S lig BM SL On the basilar membrane locates Organ of Corti (OC) Organ of Corti OC OHC tm sl IHC phc bm pc t bsl The tectorial membrane (tm) covers 3 outer hair cells (OHC) and 1inner hair cell (IHC) . At the centre the pillar cells (pc) form tunnel (t). Hair cells are supported by phalangeal cells (phc). Organ of Corti CD . . . . tectorial membrane outer hair cells inner h.c. outer phalanger cells pillar cells inner ph.c. Mechanism of hearing: under sound tympanic membrane vibrates, ossicles push oval window. perilymph moves through helicotrema to round window, calls movement of endolymph of cochlear duct and tectorial membrane which irritates hear cells. Nerve fibers take impulse. cochlear duct H At the top of the cochlear canal the SV SM scala vestibuli connects with the scala tympani – Helicotrema (H), ST G SV M perilymph moves. G Organ of equilibrium is similar to o.Corti, locates in the semicircular canals and vestibule, gives information about the force of gravity, acceleration and position of a head Organ of Taste • There are taste buds in the epithelium of the tongue papillae. Taste bud fp tb There are 3 types of cells in taste bud: 1. basal are stem cells, 2. elongated supporting cells high med 3. actual taste cells contain microvilli These cells are contacted by sensory nerves from below. Taste sensations • Tip of the tongue - sensitive to sweet and salt • Lateral edges - sensitive to sour • Posterior portion - sensitive to bitter The Cardiovascular System 3 parts: • 1. the heart pumps blood 2. MACROCERCULATION – transport 3. MICROCERCULATION – exchange of metabolites, oxygen Generalized Structure of Blood Vessels intima adventitia Types of vessels, because of hemodinamic conditions • ARTERIES: elastic, muscular-elastic, muscular • VEINS: muscular, unmuscular • CAPILLARIES: 1. continuous, 2. fenestrated, and 3. sinusoidal Elastic Arteries • Thick-walled arteries near the heart; the aorta and its major branches – Contain elastin in all three tunics – Withstand large blood pressure Muscular Artery Muscles Elastic Artery Elastic Muscular Arteries and Arterioles • Muscular arteries – far from heart, where pressure smaller – Have thick tunica media with more smooth muscle and less elastic tissue • Arterioles – smallest arteries; lead to capillaries – Control flow into capillaries, contain circular muscle Arteriole Arteriole, 1-5 smooth. muscle layers, (no) IEL Veins • Veins – have lower blood pressure and thinner walls than arteries – Valves which prevent backflow of blood 2 types: • Muscular – locate below the heart • Unmuscular – above • Venule – similar to capillary, but wider Capillaries • Capillaries are the smallest blood vessels – Wall one cell thick – endothelium on basal lamina • Types: 1.2.3. Capillaries 1. 2. 3. LOCATION Of CAPILLARIES • 1. – brain, nerves, muscles • 2. – kidney, intestine, endocrine glands • 3.– red bone marrow, liver, spleen Vein capillary venule HEART • Contains pacemaker cells • Purkinje fibers-conduct electrochemical impulses, locate between endocardium and myocardium