Frog Nervous System Essay Sample

Questions for research:
1. Organs in the major divisions of the nervous system… .
2. Functions of the nervous system… .

a. Neurons and synapses
Most nerve cells send signals via their axons. although some types are capable of dendrite-to-dendrite communicating. ( In fact. the types of nerve cells called amacrine cells have no axons. and pass on merely via their dendrites. ) Neural signals propagate along an axon in the signifier of electrochemical moving ridges called action potencies. which produce cell-to-cell signals at points where axon terminuss make synaptic contact with other cells. b. Neural circuits and systems

The basic neural map of directing signals to other cells includes a capableness for nerve cells to interchange signals with each other. Networks formed by interrelated groups of nerve cells are capable of a broad assortment of maps. including feature sensing. pattern coevals. and clocking. c. Reflexes and other stimulus-response circuits

The simplest type of nervous circuit is a automatic discharge. which begins with a centripetal input and ends with a motor end product. go throughing through a sequence of nerve cells in between. [ 51 ] For illustration. see the “withdrawal reflex” doing the manus to yank back after a hot range is touched. The circuit begins with centripetal receptors in the tegument that are activated by harmful degrees of heat: a particular type of molecular construction embedded in the membrane causes heat to alter the electrical field across the membrane. If the alteration in electrical potency is big plenty. it evokes an action potency. which is transmitted along the axon of the receptor cell. into the spinal cord. There the axon makes excitant synaptic contacts with other cells. some of which undertaking ( send axonal end product ) to the same part of the spinal cord. others projecting into the encephalon. 3. Cranial and spinal nerves…

Cranial nerve| Origin| Innervation|
Olfactory| Telencephalon| Transmits the sense of odor from the rhinal pit. [ 1 ] Located in olfactive hiatus in thecribriform home base of ethmoid. | Optic| Diencephalon| Transmits ocular signals from the retina of the oculus to the encephalon. [ 3 ] Located in the ocular canal. | Oculomotor| Anterior facet of Midbrain| Innervates the levator palpebrae superioris. superior rectus. median rectus. inferior rectus. andinferior oblique. which jointly perform most oculus motions. Besides innervates the sphincter pupillae and the musculuss of the ciliary organic structure. Located in the superior orbital crevice. | Trochlear| Dorsal facet of Midbrain| Innervates the superior oblique musculus. which depresses. rotates laterally. and intorts the orb. Located in the superior orbital crevice. | Trigeminal| Pons| Receives esthesis from the face and innervates the musculuss of chew. Located in thesuperior orbital crevice ( ophthalmic nervus – V1 ) . hiatuss rotundum ( maxillary nervus – V2 ) . andforamen ovale ( inframaxillary nervus – V3 ) . | Abducens| Nuclei lying under the floor of the 4th ventricle Pons| Innervates the sidelong rectus. which abducts the oculus. Located in the superior orbital crevice. |

Facial| Pons ( cerebellopontine angle ) above olive| Provides motor excitation to the musculuss of facial look. posterior belly of the digastric musculus. and stapedius musculus. Besides receives the particular sense of gustatory sensation from the anterior 2/3 of the lingua and provides secretomotor excitation to the salivary secretory organs ( except parotid ) and thelacrimal secretory organ. Located in and tallies through the internal acoustic canal to the facial canal and issues at the stylomastoid hiatuss. | Acoustic or Vestibulocochlear ( or auditory-vestibular nerveor acoustic nerve| Lateral to CN VII ( cerebellopontine angle ) | Senses sound. rotary motion. and gravitation ( indispensable for balance and motion ) . More specifically. the vestibular subdivision carries urges for equilibrium and the cochlear subdivision carries urges for hearing. Located in the internal acoustic canal. | Glossopharyngeal| Medulla| Receives gustatory sensation from the posterior 1/3 of the lingua. provides secretomotor excitation to theparotid secretory organ. and provides motor excitation to the stylopharyngeus. Some esthesis is besides relayed to the encephalon from the palatine tonsils. Located in the jugular hiatuss.

Vagus| Posterolateral sulcus ofMedulla Supplies branchiomotor excitation to most laryngeal and pharyngeal musculuss ( except thestylopharyngeus. which is innervated by the glossopharyngeal ) . Besides provides parasympatheticfibers to about all thoracic and abdominal entrails down to the splenetic flection. Receives the particular sense of gustatory sensation from the epiglottis. A major map: controls musculuss for voice and resonance and the soft roof of the mouth. Symptoms of harm: dysphagia ( get downing jobs ) . velopharyngeal inadequacy. Located in the jugular hiatuss. | Accessory or spinal-acccessory ( or cranial accoutrement nerveor spinal accoutrement nervus ) | Cranial and Spinal Roots| Controls the sternocleido mastoideus and cowl muscle musculuss. and overlaps with maps of the pneumogastric nervus ( CN X ) . Symptoms of harm: inability to shrug. weak caput motion. Located in thejugular hiatuss. | Hypoglossal| Medulla| Provides motor excitation to the musculuss of the lingua ( except for the palatoglossus. which is innervated by the pneumogastric nervus ) and other glossal musculuss. Important for get downing ( bolus formation ) and speech articulation. Located in the hypoglossal canal. |

Spinal Nervousnesss:
We have 31 braces of spinal nervousnesss and they are named after the subdivision of the spinal column they come out of. * 8 braces of cervical nervousnesss ( C1-C8 )
* 12 braces of pectoral nervousnesss ( T1 – T12 )
* 5 braces of lumbar nervousnesss ( L1-L5 )
* 5 braces of sacral nervousnesss ( S1-S5 )
* 1 brace of coccygeal nervousnesss ( Co1 )

Cervical Plexus
This rete is located underneath the sternocleidomastoid musculus ( from C1 – C4 ) . Most of the subdivisions innervate the tegument of cervix and deep cervix musculuss. The Phrenic nervus ( C3. C4. C5 ) gets particular reference that innervates the top of the stop ( after going down through pectoral pit. along either side of the bosom ) . Note that if both phrenic nervousnesss are cut or if the spinal cord is severed above C3. take a breathing Michigans. The Brachial Plexus

This plexus gets part from the transitional country from cervix into axilla ( armpit ) between C5 and T1. It provides about all the excitation of the upper limb ( this includes back and scapular musculuss that control the limb ) . The organisation of this rete is besides really mussy. There’s commixture of subdivisions and so a ramification of subdivisions and so blending once more. Note how there’s divisions. short pantss and roots. Five nervousnesss innervate the musculuss of the arm:

1. Musculocutaneous innervates the biceps brachii and some superimposed tegument. ( C5. C6. C7 ) 2. Median innervates anterior forearm musculuss. some intrinsic manus musculuss. and tegument of sidelong ( anatomical position/toward pollex ) thenar. ( C5. C6. C7. C8. T1 ) 3. Ulnar innervates intrinsic manus musculuss and tegument of the median manus. ( C8. T1 ) 4. Radial travels along radius and innervates Triceps brachii and musculuss of the posterior compartment. and overlying tegument. ( C5. C6. C7. C8. T1 ) 5. Axillary innervates the deltoid and teres minor. and overlying tegument. ( C5. C6 ) The Lumbar Plexus

This rete lies within the iliopsoas musculus and comes from between L1 and L4. The chief subdivisions innervate the anterior thigh. Smaller subdivisions innervate some of the abdominal wall and iliopsoas musculus. Femoral nervus — innervates quadriceps femoris musculus and overlying skin Obturator nervus — innervates adductor musculuss and overlying clamber The Sacral Plexus

The sacral rete lies caudal to the lumbar rete ( stems from L4 to S4 ) and is frequently referred together withthe lumbar rete as the lumbosacral rete. The subdivisions innervate natess. pelvic girdle. perineum and lower limb ( except for anterior and median thigh ) . Sciatic nervus. the largest nervus of the sacral rete is really two nervousnesss wrapped in one sheath: Tibial nervus ( L4. L5. S1. S2. S3 ) innervates posterior thigh. posterior leg ( lower leg ) . and intrinsic musculuss of pes Common fibular ( peroneal ) nervus ( L4. L5. S1. S2 ) innervates musculuss of the anterolateral leg ( lower leg )

ACTIVITY # 24

Ventral position
1-10 Cranial nervousnesss
1 Olfactory I
2 Ophthalmic subdivision of trigeminal V
3 Hapless IV
4 Ocular II
5 Oculomotor III
6 Facial VII
7 Trigeminal V
8 Abducents VI
9 Facial VII and audile VIII

10 Glossopharyngeal IX and pneumogastric Ten
11-20 Spinal nervousnesss
11 First
12 Second
13 Third
14 Fourth
15 Fifth
16 Sixth
17 Seventh
18 Eighth
19 Ninth

20 One-tenth
21 Sciatic nervus
22 Filum terminale
23 Sympathetic nervus cord
24 Sympathetic ganglion
25 Ramus communicans
26 Spinal cord
27 Pituitary
28 Infundibulum
29 Pituitary

30 Ocular lobe
31 Ocular decussation
32 Cerebral hemisphere
33 Olfactory lobe
34 Eyeball

QUESTIONS FOR RESEARCH:
1. | CNS| PNS| ANS|
a. Components| the encephalon and spinal cord| cranial and spinal nerves| sympathetic and parasympathetic ironss of ganglia. | b. Location| Brain is contained in a bony construction known as encephalon box or braincase and protects it from the external dazes. Brain of frog consists of a brace of occipital condyles. | 10 braces of cranial nervousnesss are present and arise from the encephalon. 10 braces of spinal nervousnesss that arise from the spinal cord emerge between the vertebrae and are located along the dorsal wall of organic structure cavity| consists of two slender nervus short pantss or cord. each with a concatenation of ganglia on either side of the spinal column | c. Distribution| Divided into five major parts. viz. : Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon| Cranial nervousnesss widening from the sidelong surfaces of the encephalon to the parts of the bodySpinal nervousnesss distributes to the limbs and bole. | operates through a series of interrelated nerve cells. often considered portion of the peripheral nervous system ( PNS ) . although many prevarications within the cardinal nervous system ( CNS ) . |

d. Function| Serves as the great centre of communicating between the chief sense variety meats and the remainder of the organic structure * Olfactory lobe of frog’s encephalon controls the sense of odor. * Ocular lobes are invloved in the frog’s vision. * Cerebellum helps to keep the balance and equilibrium of the toad. * Medulla oblongata helps in the ordinance of respiration. digestion. and other automatic maps. Cerebellum besides controls the muscular coordination and position. | Cranial nervousnesss are involved in go throughing the information from exterior to the encephalon. Spinal nervousnesss maps in go throughing information from the appendages to encephalon through spinal cord. | * helps present information to the organic structure about impending danger * responsible for the fight-or-flight response |

2. Cranial nerves…
1. Olfactory
Beginning: olfactory lobe
Location: walls of nasal Chamberss
2. Ocular
Beginning: ocular decussation.
Location: retina of the eyes
3. Oculo-Motor
Beginning: arise dorsal to the lobes of the infundibulum
Location: 4 musculuss of the oculus viz. ( superior rectus. inferior rectus. median rectus. inferior oblique musculuss ) 4. Trochlear
Beginning: arises from the encephalon between the ocular lobes and the cerebellum Location: superior oblique musculus of the oculus

5. Trigeminal
Beginning: arises from the myelin at its cephalo-lateral angle and passes into the prootic ganglion Location: musculuss of the jaws. tegument of the face. oral cavity and the lingua 6. Abducents
Beginning: Near to the mid-line of the myelin
Location: sidelong or external rectus musculus of the oculus
7. Facial
Beginning: Prootic ganglion palatine ramus
Location: musculuss of the face and pharynx
8. Auditory
Beginning: near behind the Vllth
Location: inner ear

9. Glossopharyngeal
Beginning: arises from the sides of the myelin by four roots which it possesses in common with the 10th cranial nervus Location: floor of the oral cavity. lingua and throat
10. Vagus or Pneumogastric
Beginning: arises from the sides of the myelin by four roots
Location: voice box. lungs. bosom. gorge. tummy and little bowel.