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Structure and Funct
Week 2
Question | Answer |
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Autonomic nervous system ANS ANS = 2 neurons from CNS to effectors presynaptic neuron cell body in CNS postsynaptic neuron cell body in peripheral ganglion | Motor nervous system controls glands, cardiac and smooth muscle also called visceral motor system Regulates unconscious processes that maintain homeostasis BP, body temperature, respiratory airflow ANS actions are automatic |
Visceral Reflex | Unconscious, automatic responses to stimulation of glands, cardiac or smooth muscle Receptors: detect internal stimuli -- stretch, blood chemicals, etc. Afferent neurons:connect to interneurons inthe CNS Efferent neurons:carry motor signals to effector |
Visceral Reflex HBP | High blood pressure detected by arterial stretch receptors (1), afferent neuron (2) carries signal to CNS, efferent (3) signals travel to the heart (4), heart slows reducing BP |
Sympathetic | prepares body for physical activity increases heart rate, BP, airflow, blood glucose levels, etc Shoot (Sympathetic) (Ejaculation) lateral horns of spinal cord (T1-L2) 3 cervical, 11 thoracic, 4 lumbar, 4 sacral and 1 coccygeal ganglia white and gray |
Sympathetic | Neuronal divergence predominates each preganglionic cell branches and synapses on multiple postganglionic cells produces widespread effects on multiple organs |
Parasympathetic | Parasympathetic division calms many body functions and assists in bodily maintenance digestion and waste elimination |
Parasympathetic Terminal ganglia in/near target organs long preganglionic, short postganglionic fibers | Origin of preganglionic fibers pons and medulla (for cranial nerve nuclei) sacral spinal cord segments S2-S4 Pathways of preganglionic fibers cranial nerves III, VII, IX and X arising from sacral spinal cord pelvic splanchnic nerves and inferior hyp |
Parasym Cranial Nerves | Oculomotor nerve (III) narrows pupil and focuses lens Facial nerve (VII) tear, nasal and salivary glands Glossopharyngeal (IX) parotid salivary gland Vagus nerve (X) viscera as far as proximal half of colon Cardiac, pulmonary, and esophageal plex |
Neurotransmitters and Receptors Effects on ANS | determined by types of neurotransmitters released and types of receptors on target cells |
Neurotransmitters and Receptors Effects on Symp | Sympathetic has longer lasting effects neurotransmitters persist in synapse and some reach the bloodstream |
Substances Released as Neurotransmitters | enkephalin, substance P, neuropeptide Y, neurotensin, nitric oxide (NO) NO inhibits muscle tone in BV walls (vasodilation) |
Adrenal Glands | Paired glands sit on superior pole of each kidney Cortex:secretes steroid hormones Medulla:a modified sympathetic ganglion stimulated by preganglionic sympathetic neurons Secretes neurotransmitters into blood catecholamines (85% EP and 15% NE) |
Cholinergic Receptors for Ach | nicotinic receptors on all ANS postganglionic neurons, in the adrenal medulla, and at neuromuscular junctions (skeletal muscle) excitatory when ACh binding occurs muscarinic receptors on all gland, smooth muscle and cardiac muscle cells that receives |
Adrenergic Receptors for NE | Norepinephrine binds to 2 classes of receptors alpha adrenergic receptors (often excitatory) beta adrenergic receptors (often inhibitory) Exceptions existence of subclasses of each receptor type alpha 1 and 2; beta 1 and 2 |
Dual Innervation | Most of viscera receive nerve fibers from both parasympathetic and sympathetic divisions Both divisions do not normally innervate an organ equally |
Dual Innervation Antagonist effects | oppose each other exerted through dual innervation of same effector heart rate decreases (parasympathetic) heart rate increases (sympathetic) exerted because each division innervates different cells pupillary dilator muscle (sympathetic) dilates pupi |
Dual Innervation Cooperative effects | seen when 2 divisions act on different effectors to produce a unified effect parasympathetics increase salivary serous cell secretion sympathetics increase salivary mucous cell secretion |
W/O Dual Innervation | Only sympathetic: adrenal medulla, arrector pili muscles, sweat glands and many blood vessels sympathetic stimulation increases blood to skeletal and cardiac muscles -- reduced blood to skin: Sweaty palms bp goes up sympathetics, Go to extremities |
Sympathetic and Vasomotor Tone | Sympathetic division prioritizes blood vessels to skeletal muscles and heart in times of emergency. Blood vessels to skin vasoconstrict to minimize bleeding if injury occurs during stress or exercise. |
Control of ANS Cerebral | cerebral cortex has an influence |
Control of ANS Hypothalamus | (major visceral motor control center) nuclei for primitive functions – hunger, thirst |
Contrl of ANS Midbrain, Pons, and Medulla O | nuclei for cardiac and vasomotor control, salivation, swallowing, sweating, bladder control, and pupillary changes |
Control of ANS Spinal Cord Reflexes | defecation and micturition reflexes integrated in cord brain can inhibit these responses consciously |
Sympathomimetics | stimulate receptors or inc norepinephrine release |
Sympatholytics | suppress sympathetic activity block receptors or inhibit norepinephrine release |
Parasympathomimetics | enhance activity while parasympatholytics suppress activity |
Management of Clinical Depression | Prozac blocks reuptake of serotonin to prolong its mood-elevating effect MAO inhibitors interfere with breakdown of monoamine neurotransmitters |
Caffeine | competes with adenosine (inhibitory; causes sleepiness) by binding to its receptors |
Cranial Nerves | competes with adenosine (inhibitory; causes sleepiness) by binding to its receptors |
Cranial Nerves List | Olfactory nerve I Oculomotor nerve III Trochlear nerve IV Trigeminal nerve V Abducens nerve VI Facial nerve VII Vestibulocochlear VIII Glossopharyngeal nerve IX Vagus nerve X Accessory nerve XI Hypoglossal nerve XII |
Olfactory Nerve I | Sense of smell Damage causes impaired sense of smell |
Optic Nerve II | Provides vision Damage causes blindness in visual field |
Oculomotor nerve III | Eye movement, opening of eyelid, constriction of pupil, focusing Damage causes drooping eyelid, dilated pupil, double vision, difficulty focusing and inability to move eye in certain directions 4 recti muscles 2 oblique muscles Lavator palpi |
Trochlear IV | Eye movement (superior oblique muscle) Damage causes double vision and inability to rotate eye inferolaterally |
Trigeminal nerve V | Sensory to face (touch, pain and temperature) and muscles of mastication Damage produces loss of sensation and impaired chewing Tigonometry Mandibular Maxillary Opthalmic Muscles of mastication Cranial Nerve V |
Abducens nerve VI | Provides eye movement (lateral rectus m.) Damage results in inability to rotate eye laterally and at rest eye rotates medially |
Facial nerve VII | Motor - facial expressions; salivary glands and tear, nasal and palatine glands Sensory - taste on anterior 2/3’s of tongue Damage produces sagging facial muscles and disturbed sense of taste (no sweet and salty) |
Vestibulocochlear nerve VIII | Provides hearing and sense of balance Damage produces deafness, dizziness, nausea, loss of balance and nystagmus |
Glossopharyngeal nerve IX | Swallowing, salivation, gagging, control of BP and respiration Sensations from posterior 1/3 of tongue Damage results in loss of bitter and sour taste and impaired swallowing |
Vagus nerve X | Swallowing, speech, regulation of viscera Damage causes hoarseness or loss of voice, impaired swallowing and fatal if both are cut |
Accessory nerve XI | Swallowing, head, neck and shoulder movement damage causes impaired head, neck, shoulder movement; head turns towards injured side |
Hypoglossal nerve XII | Tongue movements for speech, food manipulation and swallowing if both are damaged – can’t protrude tongue if one side is damaged – tongue deviates towards injured side; see ipsilateral atrophy |
Cranial nerve disorders | Trigeminal neuralgia (tic douloureux) recurring episodes of intense stabbing pain in trigeminal nerve area (near mouth or nose) Bell’s palsy disorder of facial nerve causes paralysis of facial muscles on one side may appear abruptly recovery 3-5wks |
Temporal bone | squamous part zygomatic process mandibular fossa and TMJ tympanic part external auditory meatus styloid process mastoid part mastoid process mastoiditis from ear infection mastoid notch digastric muscle |
Petrous Portion of Temporal Bone | Part of cranial floor separates middle from posterior cranial fossa Houses middle and inner ear cavities receptors for hearing and sense of balance internal auditory meatus = opening for CN VII (vestibulocochlear nerve) |
Opennings of Temporal Bone | Carotid canal passage for internal carotid artery supplying the brain Jugular foramen irregular opening between temporal and occipital bones passageway for drainage of blood from brain to internal jugular vein |
Occipital Bone | Rear and base of skull Foramen magnum holds spinal cord Skull rests on atlas at occipital condyles Hypoglossal canal transmits hypoglossal nerve (CN XII) supplying tongue muscles External occipital protuberance for nuchal ligament Nuchal lines mark n |
Sphenoid Bone | Lesser wing optic foramen Greater wing foramen rotundum and ovale for brs. trigeminal nerve foramen spinosum for meningeal artery Body of sphenoid sella turcica contains hypophyseal fossa houses pituitary gland Medial and lateral pteryg |
Ethmoid Bone | Between the orbital cavities Lateral walls and roof nasal cavity Cribriform plate and crista galli Ethmoid air cells form ethmoid sinus Perpendicular plate forms part of nasal septum Concha (turbinates) on lateral wall |
Maxillary Bone | Forms upper jaw alveolar processes are bony pointsbetween teeth alveolar sockets hold teeth Forms inferomedial wall of orbit infraorbital foramen Forms anterior 2/3’sof hard palate incisive foramen cleft palate |
Paranasal Sinuses | Sphenoid sinus Frontal sinus Ethmoid Sinus Maxillary sinus |
Palatine Bones | L-shaped bone Posterior 1/3 of the hard palate Part of lateral nasal wall Part of the orbital floor |
Zygomatic Bones | Forms angles of the cheekbones and part of lateral orbital wall Zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal bone |
Lacrimal Bones | Form part of medial wall of each orbit Lacrimal fossa houses lacrimal sac in life tears collect in lacrimal sac and drain into nasal cavity |
Nasal Bones | Forms bridge of nose and supports cartilages of nose Often fractured by blow to the nose |
Inferior Nasal Conchae | A separate bone Not part of ethmoid like the superior and middle concha or turbinates |
Vomer | Inferior half of the nasal septum Supports cartilage of nasal septum |
Mandible | Only movable bone jaw joint between mandibular fossaand condyloid process Holds the lower teeth Attachment of muscles of mastication temporalis muscle onto coronoid process masseter muscle onto angle of mandible Mandibular foramen Mental foramen |
Auditory Ossicles | malleus, incus, and stapes |
Hyoid Bone | suspended from styloid process of skull by muscle and ligament greater and lesser cornua |
Superficial Muscles of Facial Expression List | Frontalis Orbicularis oculi Levator labi superioris Zygomaticus minor Zygomaticus major Risorius Modiolus Depressor anguli oris Depressor labii inferioris Platysma |
Musculature of Tongue | Intrinsic muscles = vertical, transverse and longitudinal Extrinsic muscles connect tongue to hyoid, styloid process, palate and inside of chin Tongue shifts food onto teeth and pushes it into pharynx Intrinsic Muscles of Tongue are Hypoglossal VII |
Muscles of Mastication | 4 Major muscles Arise from skull and insert on mandible Temporalis and Masseter elevate the mandible Medial and Lateral Pterygoids help elevate, but produce lateral swinging of jaw Temporalis and Masseter Close Your Mouth |
Suprahyoid Muscles and Swallowing | Digastric and Mylohyoid = open mouth Geniohyoid = widens pharynx during swallowing Stylohyoid = elevates hyoid Thyrohyoid = elevates larynx, closing glottis Digastric opens your mouth |
Triangles of the Neck | Anterior triangles Muscular Carotid Submandibular Submandibular Suprahyoid Posterior triangles Occipital Omoclavicular Sternocleidomastoid |
Muscles Invovled in Swallowing | Pharyngeal constrictors push food down throat Infrahyoid muscles pulls larynx downward Intrinsic laryngeal muscles control speech |
Face Landmarks Lateral | Occipital Frontal Orbital Temporal Nasal Auricular Oral Buccal Mental Cervical Nuchal |
Face Landmarks Anterior | Frons Root of Nose Bridge of Nose Superciliary ridge Superior palpebral Lateral commissure Medial commissure Inferior palpebral sulcus Dorsum nasi Auricle Apex of nose Ala nasi Philtrum Labia Mentolabial sulcus Mentum Trapezius muscle Ste |
Deep Muscles in Facial Expression | Galea aponeurotica Corrugator supercilii Nasals Levator anguli oris Masseter Buccinator Orbicularis oris Mentalis |