ANAPHY AND PHYSIOLOGY (ANPH111) Review - PDF

ANAPHY AND PHYSIOLOGY (ANPH111) Coverage: − Part of the central nervous system contained within the skull o Nervous System − Most comp...

ANAPHY AND PHYSIOLOGY (ANPH111) Coverage: − Part of the central nervous system contained within the skull o Nervous System − Most complex and largest mass of nervous tissue in the body and contains literally o General and Special senses billions of nerve cells. o Endocrine System − The average weight of the human brain in the adult is approximately 1380 grams in o Blood the male and 1250 grams in the female. o Cardiovascular system, Heart, Blood vessels Embryological Divisions of the Brain: NERVOUS SYSTEM − Brain is originated from a tube − sa una magkakaroon ng tatlong umbok (Forebrain, Midbrain and Hindbrain) − A group of tissues composed of highly specialized cells possessing the 1. Forebrain (Prosencephalon) characteristics of excitability and conductivity. a. Telencephalon (Cerebrum) Morphological divisions: b. Diencephalon (thalamus, hypothalamus, epithalamus, subthalamus) 1. Central nervous system 2. Midbrain (Mesencephalon) a. Brain a. Corpora quadrigemina (tectum) b. Spinal cord − 2 superior colliculi – visual reflexes 2. Peripheral nervous system − 2 inferior colliculi – auditory reflexes a. Cranial nerves (12 pairs) b. Cerebral peduncles b. Spinal nerves (31 pairs) c. Vertebral Aqueduct of Sylvius (iter) c. Autonomic nervous system 3. Hindbrain (Rhombencephalon) Functional divisions: a. Metencephalon (cerebellum, pons) 1. Somatic efferent b. Myelencephalon (medulla oblongata) − Innervating somatic structures like skeletal muscles and skin. − Pertaining to the body Forebrain (Prosencephalon) 2. Visceral efferent A. Cerebrum (Telencephalon) − Innervating visceral or involuntary structures like smooth muscles, cardiac 7 − 8 of weight of brain muscles and glands. − This is autonomic nervous system. − discriminatory identification; integration of sensory information; memory; reasoning; Types of cell in the nervous system: for use of language; for emotional behavior; for initiation of movement 1. Neurons Fissures of Cerebrum: − The active conducting elements − Fissure - Deep depression − This is the Parenchymal – functional cells − Shallow – sulcus – singular 2. Neuroglia − Sulci – Plural − the supporting elements − Deep – Fissures a. Astrocyte − In the spinal cord, you don’t interchange the fissure and sulcus. − involve in the blood brain barrier. Types of fissures b. Oligodendrocyte 1. Longitudinal Fissure − Produce myelin sheath in the central nervous system. − Separating 2 cerebral hemisphere c. Microglia 2. Lateral Sylvian Fissure − Phagocytic cells (protecting) − Separate your frontal lobe and parietal lobe above from the temporal lobe. − Nangangain ng Microorganisms − End of lateral sylvian fissure is Supramarginal Gyrus. d. Ependymal cells − Antero median fissure – don’t interchange the fissure and sulcus because − lining the ventricles at the brain and central canal of spinal cord. anteriorly ang spinal mo hinahati sya ng deep groove − Flow of Cerebrospinal fluid, fluid of your brain. − Dorso median fissure – shallow groove Neuron − Lumalabas un Middle cerebral artery − Basic unit of the nervous system which conducts electrical impulses from one part 3. Central Sulcus (Rolandic Fissure) of the body to another. − Depression that separating the frontal lobe and the parietal lobe. Two types of processes: 4. Transverse Fissure 1. Dendrites − Between the cerebellum and the cerebrum. − Transmit impulses toward the cell body. − Cerebellum –little brain − Afferent process − Cerebrum – big brain 2. Axons 5. Parieto – occipital Fissure − Conducting impulses away from the cell body. − Between the occipital and parietal lobes. − Efferent process − Middle surface of the brain Synapse 6. Calcarine Fissure − point of connection between neurons. − Found in the occipital lobe Main neurotransmitters: − Visual center (calcarine area) − that will allow the conduction of impulse to pass through from one neuron to − 2 parts of visual area: Cuneus and Lingual gyrus another. Superior Temporal Sulcus 1. Epinephrine (Adrenalin) − Temporal lobe 2. Norepinephrine (Nor Adrenaline) − yun dulo nya, Angular gyrus 3. Acetylcholine Nerve impulse: Lobes of the Cerebral cortex: 1. Myelin Sheath 1. Frontal lobe − Insulating material covering axons in central and peripheral nervous system. − Includes all the cortex lying anterior to the central sulcus of Rolando and above − The electrical impulse jumps from node to node in myeline sheath instead of the lateral sulcus sylvius. traveling continuously along the nerve fiber. (Saltatory Conduction of − Center for motor functions and personality. Impulses) 2. Parietal lobe − Node of Ranvier - periodic gap in the insulating myelin sheath on the axon of − Lies posterior to central sulcus of Rolando and above lateral Sylvian fissure. certain neurons that serves to facilitate the rapid conduction of nerve impulses. − Center for sensory functions 3. Temporal lobe CENTRAL NERVOUS SYSTEM − Lies beneath the lateral sulcus of Sylvian − Includes the brain and spinal cord. − Center for hearing and olfaction. Central nervous system is divided grossly into 4. Occipital lobe 1. Gray matter − Occupies the posterior extremity of the cerebral hemisphere behind parieto- − So, called because of its appearance and preponderance of nerve cell bodies and occipital fissure. true dendrites. − Visual center − Outer part in brain; inner part in spinal cord 5. Insula (Island of Reil) 2. White matter − Exposed when the lips of lateral Sylvian fissure are separated. − Composed chiefly of myelinated nerve fibers − Icucut ng coronal and makikita yun lateral sulcus, un nasa gilid tapos nandoon − Inner part in brain; outer part in spinal cord sa loob yun Insula. Ganglion/ganglia cells Functional areas of the cerebrum: − Group or aggregates of nerve cell bodies outside the Central Nervous System Brain 1. Primary Motor area or Pre-central gyrus TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) − Lies in the frontal lobe immediately anterior to the central sulcus − Production will be by the choroid plexus, which are present in all of the ventricles − Controls voluntary movements in the opposite side of body. of the brain − Brodmann’s area 4 − Nagbibigay ng nutrition and immune function 2. Pre-motor Area − Colorless, with a composition similar to that of lymph. − In front of the motor area − Exerts a controlling influence over the motor area, ensuring an orderly series of Ventricles of the brain: movements. − absorption will be by the Arachnoid villi or Arachnoid granulate 3. Pre-frontal area − Concerned with behavior, character and emotional state of the individual. 1. Lateral ventricle − Concerned with foresight, good judgement, abstract thinking. − Found inside the cerebral hemispheres 4. Primary sensory/ somesthetic area or Post- central gyrus − Interventricular foramen (foramen of Monroe) − Lies behind the central sulcus of Rolando in parietal lobe − Under the corpus callosum − Sensations of pain, temperature, pressure, and touch, position and movement 2. Third ventricle sensation from opposite side of body are received and interpreted. − Between the 2 thalamic nuclei, continuous with the cerebral aqueduct of Sylvius − Brodmann’s area 3, 1, 2 3. Fourth ventricle 5. Motor speech area − Communicates with subarachnoid space through foramen of Luschka and − Lies in inferior frontal gyrus of dominant hemisphere Magendie − Will control the muscles that you used for talking. − Iter – cerebral aqueduct of sylvius (this is the communication between third − Middle cerebral artery – dito lumalabas sa lateral sylvian fissure; sinusupply nya ventricle and fourth ventricle) yun mga primary motor, primary sensory, motor speech area. − Frontal lobe is divided to 3 gyri: Superior frontal gyrus, middle frontal gyrus Meninges and inferior frontal gyrus − Three membranes collectively known as the meninges provide protection to the − 3 part of inferior frontal gyrus: Pars opercularis, Pars triangularis and Pars brain and spinal cord. orbitalis- (not part of Broca’s area) From outside in, there are the: − Pars opercularis – Brodmann’s 44 a. Dura Mater – outermost (below of dura mater, there have Subdural space) − Pars triangularis – Brodmann’s 45 b. Arachnoid mater – middle (below this, there have subarachnoid space) − Broca’s area (Brodmann’s area 45, 44) c. Pia mater – innermost (closely adherent to the brain) Spinal Cord B. Diencephalon − Continuous with the medulla oblongata above 1. Thalamus − Extends from the level of foramen magnum to the lower border of 1 st lumbar − Relay center for sensory impulses (except olfactory) from peripheral receptors to vertebra in adult and level of L3 vertebra in children. cerebral cortex. − Average length: 45 cm 2. Hypothalamus 2 enlargements: − Involved in the regulation of body temperature, feeding activities, biorhythm, 1. Cervical enlargement emotion, etc. − Where nerve supply of arms arises from − Upper extremities Corpus Callosum − C4 to T2 − Largest commissural fibers 2. Lumbar enlargement Callosal Sulcus − Where nerve supply of legs arises from − Depression above the corpus callosum − Lower extremities Cingulate Gyrus − Level of 10th thoracic vertebra; widest at the 12th thoracic vertebra − Above the corpus callosum and callosal sulcus. − It narrows down was conus medullaris, where it gives rise to the thread-like Cingulate Sulcus filum terminale. − Depression above the cingulate gyrus − that will be attached to your coccygeal vertebral − The lumbar and sacral spinal nerves descend along the filum terminale in a Cerebellum bundle known as the cauda equina. (horse tail like) − Oval in shape with a central constriction and lateral expanded portions. − Vermis - the constricted centra; portion– as a connection (Latin of worm) and the PERIPHERAL NERVOUS SYSTEM lateral expanded portions the hemisphere. I. Cranial Nerves − 2 lobes: Vermis and Corpus Callosum II. Spinal Nerves Divided into lobes by deep and distinct fissures, these lobes include the: III. Autonomic Nervous system a. Anterior Lobe − Regulation of muscle tone Cranial Nerves b. Posterior Lobe − 12 pairs of symmetrically arranged nerves attached to the brain − Coordination of voluntary motor activity  3, 4 – midbrain c. Flocculonodular lobe  5, 6, 7, 8 – pons − Concerned with the function of equilibrium, posture and balance  9, 10, 11, 12 – medulla oblongata  (S) – Purely sensory nerve Midbrain (mesencephalon)  (M) – Purely motor function − Connects the forebrain and hindbrain  (Mx) – Mixed Nerve − Concerned with motor coordination  (PS) – Parasympathetic a. Cerebral peduncles − found anteriorly Types of Nerves − pair of cylindrical bodies made up of nerve fiber tracts which connect the forebrain 1. Olfactory (I) with the hindbrain. − (S) nerve for smell. b. Corpora quadrigemina − Located in the axons of superior concha of nose. − Found posteriorly − Tutusok sya sa cribriform plate of ethmoid para tumusok doon sa olfactory bulb 1. Superior colliculi – upper 2; for visual reflexes at dadaloy sa olfactory tract. 2. Inferior colliculi – lower 2; for auditory reflexes − Anosmia – loss of the sense of smell 2. Optic (II) Pons − (S) Nerve arising from the eye; for vision − Lies anterior to the cerebellum and between the midbrain and medulla. − Magcocross sya sa optic chiasm − Bridge-like structure, consisting almost entirely of white matter linking the various − Anopsia – blindness parts of the brain. 3. Oculomotor (III) Medulla Oblongata − (M) Arise in between your cerebral peduncle; Found in brainstem. − Continuous with the spinal cord inferiorly with the spinal cord inferiorly and with − Innervate the extraocular muscles of the eye the pons superiorly. − Exception: LR6 – Lateral rectus muscles of the eye that innovated by − Lies ventral to the cerebellum abducens; SO4 – superior oblique innovated by trochlear. − Has a number of vital regulatory and reflex centers, including those controlling − (PS) – innervates the iris. the circulatory system, breathing, swallowing, vomiting, coughing, sneezing. 4. Trochlear (IV) Cerebrospinal Fluid (CSF) − (M) only cranial nerve that will arise from posterior surface of the brainstem. − Circulating within the ventricles, the central canal of the spinal cord and also − Thinnest nerve within the subarachnoid space. − Innovating your superior oblique muscle TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) 5. Trigeminal (V) − From L4, L5, S1, S2, S3 spinal nerves − (Mx) Largest of the cranial nerves − The largest branch which is the sciatic nerve (the largest nerve in the body) − 3 branches: ophthalmic, mandibular and maxillary − Posterior aspect of lower extremities − Sensory – general sensation on the anterior 2/3 of the tongue, special Sciatic nerve divides into: sensation - taste sensation innovated by the facial nerve; motor – yun a. Tibial nerve mandibular division ay nag susuply sa muscles of mastication = Mixed Nerve b.Common peroneal nerve (Mx) 6. Abducens (VI) Thoracic Spinal Nerves − (M) – LR6 innovating by abducens − Do not form plexuses 7. Facial (VII) − Independent nerves − (Mx) Sensory – special sensation of taste anterior 2/3 of the tongue; Motor – − T1 – T11 spinal nerves = Intercostal nerves nagsusupply sa mga muscles of facial expression = Mixed Nerve (Mx) − T12 spinal nerves = Subcostal nerve − (PS) – glands; innovation of the lacrimal glands and salivary glands except parotid gland. Autonomic System 8. Vestibulocochlear (acoustic) (VIII) 1. Sympathetic/ Thoracolumbar Divisions − (S) hearing − Arises from all the thoracic and the first three lumbar segments of the spinal 9. Glossopharyngeal (IX) cord − (Mx) Night cranial nerve − Sympathetic - responding to dangerous or stressful situations; fight or flight − Sensory – will innovate the general and special sensation on the posterior 1/3 2. Parasympathetic/ Craniosacral Divisions of the tongue, (taste and touch); − Arises from the third, seventh, ninth, and tenth cranial nerves and from the − Motor – innovate the muscles of the tongue, Palatoglossus and muscles of second, third and fourth sacral segments of the spinal cord. pharynx, stylopharyngeus = Mixed Nerve (Mx) − Repost and repair − (PS) – innovation of Parotid gland − Parasympathetic - responsible for the body's relaxation response, and it also 10. Vagus (X) plays a large part in regulating digestion, heart rate, and breathing; rest and digest − (Mx) Longest nerve − Sensory – internal organs; Motor – laryngeal muscles that you use for talking Function of the Autonomic Nervous System and pharyngeal muscles use for swallowing. = Mixed Nerve (Mx) − (PS) - smooth muscle of the visceral/ internal organs Organ Sympathetic Parasympathetic 11. Accessory (XI) Eye: − (M) Spinal accessory or accessory spinal Iris Dilates pupil Constricts pupil Ciliary muscle Flattens lens Bulges lens − Innovation of sternocleidomastoid and trapezius Peripheral blood Vasoconstriction (increased blood Vasoconstriction (decrease BP) 12. Hypoglossal (XII) vessels pressure) − (M) innervates the tongue muscles except the palatoglossus Stimulates serous secretion Salivary glands Stimulates viscous (mucous) Classification of Cranial Nerves Lacrimal glands None Stimulates secretion A. Sensory Nerves Sweat gland Copious (sweating) None − Carry impulses towards brain Heart sa node Increased rate Decreased rate muscle Increased force of − Also called afferent fibers contraction − Cranial nerves: I, II, VIII Lungs: B. Motor Nerves Bronchi Dilation Constriction Stomach - Decrease motility and tone - Increased motility − Carry impulses away from the brain. Wall - Stimulates secretion of alkaline juice - Stimulates secretion of acid with high − Also called efferent fibers Glands with low enzyme activity enzyme activity − Cranial nerves: III, IV and VI which supply the eye muscles; XI and XII Suprarenal gland Secretion of epinephrine None Medulla C. Mixed Nerves Urinary bladder − Carry both sensory and motor nerve fibers Wall Inhibition Excitation Sphincter Excitation Inhibition − Cranial nerves: V, VII, IX, X Penis Ejaculation Erection Arrector pili Contraction None Spinal Nerves Muscles of hair Follicles − A bundle of nerve fibers attached to spinal cord Arterioles Contraction Dilatation − 31 pairs of nerves called spinal nerves arise from the spinal cord along Splanchnic almost its entire length and emerge from the vertebral canal through the Region and skin intervertebral foramina − There are eight pairs of cervical spinal nerves: 12 thoracic, 5 lumbar, 5 SENSATION sacral and 1 coccygeal. − Always mixed nerves − Senses - Brain receives information about the environment and the body − Union of dorsal root and ventral root − Sensation – process initiated by stimulating sensory receptors and perception a. Dorsal root − Perception – conscious awareness of those stimuli − Containing fibers of sensory neurons Five recognized senses: b. Ventral root o Smell − Containing fibers of motor neurons o Taste − These 2 roots join together to form spinal nerve o Vision o Hearing o Touch Plexuses Senses are divided into two: − Group of nerve fibers from ventral rami of cervical, lumbar and sacral spinal nerves. o General senses Posterior rami never from plexuses. o Special senses Types of Plexus 1. Cervical plexus SENSORY RECEPTORS − Formed by the first 4 cervical nerves (C1, C2, C3, C4) − Nerve endings or specialized cells capable of responding to stimuli by developing − This supplies the back and sides of the head and the front of the neck action − Gives off the phrenic nerve to the diaphragm Receptors: 2. Brachial plexus o Mechanoreceptors – respond to mechanical stimuli; bending and stretching − Lower 4 cervical (C5, C6, C7, C8) nerves and 1st thoracic (T1) supplies the skin o Chemoreceptors – respond to chemicals. and muscles of the upper limb/extremities. o Photoreceptors – respond to light − Gives off large nerves: circumflex, radial, median, ulnar and o Thermoreceptors – respond to temperature changes musculocutaneous nerves. o Nociceptors (noceo = to injure) – respond to stimuli that result in the sensation 3. Lumbar plexus of pain − From L1-L4 spinal nerves GENERAL SENSES − Anterior portion and medial portion − Largely distributed over the part of the body a. Obturator nerve Divided into two: − Arising from anterior division of L2, L3, L4 spinal nerves A. Somatic − Supplies the muscles and skin on medial aspect of thigh a.Touch b. Femoral nerve b.Pressure − Arising from the posterior divisions of L2, L3, L4 spinal nerves c. Proprioception − Supplies muscles and skin on anterior aspect of the thigh d.Temperature 4. Sacral plexus e.Pain TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) B. Visceral Conscious Proprioceptive Pathway a.Pain Receptors: Paccinian corpuscle, Meissner's corpuscle, Muscle b.Pressure spindles /Tendon spindles I. Somatosensory system  N1 General senses: − Dorsal Root Ganglion 1. Light touch or tactile discrimination − Axons do not synapse with the posterior horn cells but instead these fibers 2. Pressure ascend on the same side forming the fibers of fasciculus gracilis and 3. Touch fasciculus cuneatus 4. Pain − These fibers synapse with the nucleus gracilis (medial) or nucleus 5. Temperature cuneatus (lateral) at the level of lower medulla. 6. Limb position  N2 Receptors − Nucleus of fasciculus gracilis or cuneatus − Neurons that will receive the stimulus − The fibers from the cells of the nuclei then cross the midline forming the  Meissner’s corpuscles – touch decussations of the medial lemniscus.  Hair follicle nerve ending – touch − Medial Lemniscus then ascend in brainstem until it terminates at ventral  Merkel’s tactile disc – touch postero-lateral nucleus of thalamus (entry)  Pacinian corpuscle – pressure  N3  Krause end bulb – cold − Ventro-postero-lateral nucleus of thalamus  Ruffini’s nerve ending – hot /warm − Fibers are then projected into the primary somesthetic areas 3,1,2 of the  Free nerve ending – pain postcentral gyrus.  Muscle spindle – proprioception  Center - Brodmann's area 3, 1, 2 (side contralateral to N1 - N3)  Golgi tendon organ/ tendon spindle – proprioception Fasciculus Gracilis General sense pathways − nerve fibers that carry impulses coming from the lower extremity 1.First order neuron: also called sensory neuron or N1 − these fibers enter the spinal cord thru the sacral, lumbar and lower thoracic 2.Second order neuron or association neuron: N2 segments 3.Third order neuron: N3 Fasciculus Cuneatus Ascending fiber tracts: − formed of fibers that carry impulses arising from the upper extremity 1.Anterolateral system − these fibers enter the spinal cord thru upper thoracic segments A. Lateral spinothalamic tract - for pain and temperature except head region Clinical signs of injury to the lemniscal pathway B. Anterior spinothalamic tract - crude touch or light touch except head region 2.Pathways to the cerebellum 1.Inability to recognize limb position A. Posterior Spinocerebellar tract - for unconscious proprioception 2.Astereognosia : inability to identify an object by touch with eyes closed B. Anterior Spinocerebellar tract 3.Loss of vibration sense 4.Loss of two point discrimination − unconscious proprioception 5.Positive Rhomberg’s sign: abnormal increase in the degree of body sway with − Both A and B carry information to the cerebellum from the lower limbs eyes closed 3.Cuneocerebellar tract - for unconscious proprioception Unconscious Proprioception 4.Posterior Column/Dorsal Column/Lemniscal System Pathway – Spinocerebellar Tract − conscious proprioception 1.Anterior spinocerebellar tract - relays proprioceptive information regarding − deep pressure and discriminative touch group of muscles at the lower extremity − vibratory sense; position sense 2.Posterior spinocerebellar tract - relays proprioceptive information regarding − Stereognosia - ability to recognize familiar objects by touch with eyes closed the status of individual muscle at lower extremity a. Gracile fasciculus - conscious proprioception for lower extremity 3.Cuneo-cerebellar tract - relays proprioceptive information regarding the status b. Cuneate fasciculus - conscious proprioception for upper extremity of the muscles in the upper extremity Pain and temperature pathway Anterior spinocerebellar tract Pathway: Lateral Spinothalamic Tract Pathway: anterior spinocerebellar tract Receptors: free nerve endings, Krause end bulb, Ruffini’s corpuscle Receptor: Muscle spindle  N1 - Dorsal Root Ganglion  Golgi tendon organ from lower extremity  N2  Enter the spinal cord thru the sacral, lumbar, and lower 6 thoracic segments − Dorsal horn cells (spinal cord)  N1 - Dorsal Root Ganglion − Laminae V-VII  N2 − Axons cross to the contralateral side and ascend as lateral spinothalamic − Dorsal horn cells mainly laminae V, VI,VII tract − Decussate on the contralateral side  N3 - Ventroposterolateral Nucleus ( side contralateral to receptor), (Thalamus ) − ascend as Ventral or Anterior Spinocerebellar Tract  Center: Broadmann’s area 3,1,2 ( primary somesthetic area in the post central − passes in Superior Cerebellar Peduncle. gyrus) side contralateral to receptor)  N3 - Cerebellar cortex When you have lesion in left side of the brain, the manifestation will be the right side of the body. You cannot feel the pain from the right side of the body, if you have lesion in Posterior spinocerebellar tract left side of the brain. Because the pathway will be crossing to the other side of your Pathway: posterior spinocerebellar tract spinal cord. Receptor: Muscle Spindle, Golgi tendon Organ  Enter the spinal cord thru sacral, lumbar, and lower six thoracic segments Crude Touch (Light Touch Pressure)  N1 Pathway: Ventral/Anterior Spinothalamic tract − Dorsal Root ganglion Receptor : Meissner's corpuscle Merkel's disc, Hair Follicle nerve ending, − Axons of dorsal root ganglion synapse with dorsal nucleus of Clark on the  Fibers synapse with dorsal root ganglion cells same side.  N1  N2 − Dorsal Root Ganglion − Dorsal Nucleus of Clark in laminae VII − axons of dorsal root ganglion make synapses with neurons in spinal cord − Axons ascend on ipsilateral side as Posterior Spinocerebellar Tract  N2 − passes in Inferior Cerebellar Peduncle − Laminae VI, VII , VIII  N3 - Cerebellar cortex − Axon from the laminae will then go to the contralateral side passing thru the anterior white commissure as origins in the ventral funiculus of the ventral Cuneo-cerebellar tract spinothalamic tract Pathway: Cuneo-cerebellar tract − Fibers will then ascend as the ventral spinothalamic tract on the contralateral Receptors: Muscle Spindle, Tendon Spindle, Cutaneous and Joint Receptors side  N1 − Fibers will continue to ascend until they terminate at the ventral posterolateral nucleus of thalamus. − Dorsal Root Ganglion of the spinal cord at the level of cervical and upper six thoracic segments.  N3 - Ventro-postero-lateral nucleus of thalamus (side contralateral to NI -> N3)  Center - Brodmann's area.3, 1, 2 (side contralateral to N1-> N3) − Fibers will synapse with Accessory Cuneate Nucleus.  N2 Discriminative Touch, Deep Pressure and Proprioceptive Pathway − Accessory Cuneate Nucleus Pathway: Posterior Column/Dorsal Column/Medial Lemniscal − Axons of N2 will ascend on ipsilateral side as Cuneocerebellar Tract − Passes in Inferior Cerebellar Peduncle Pathway/ TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111)  N3 - Cerebellar cortex − Located above the lateral ends of each eye − Continually release a dilute salt solution (tears= “ lacrimal fluid) that drain into II. Motor System the nasal cavity through the inferior meatus A. PYRAMIDAL SYSTEM: mainly concerned with the production of skilled voluntary − Lacrimal fluid not only moistens and lubricates conjunctival sac but also reduces movements eye infections because it contains bactericidal enzyme (lysozyme) Extrinsic Eye Muscles Orticospinal tract Control Movement of Eyeball Action Nerve Supply Lateral rectus moves eye Laterally VI Origin: Primary motor area or BA 4, 6 (Cerebral cortex) Medial rectus moves eye medially III  Descend on the ipsilateral side of the midbrain, pons and medulla Superior rectus moves eye Upwards medially III  90% of the fibers cross the medullary decussation to become the Lateral Inferior rectus moves eye Downwards and medially III Inferior oblique moves eye Upwards and laterally III Corticospinal Tract Superior oblique moves eye Downwards and laterally IV  10% of the fibers do not cross the medullary decussation to become the anterior corticospinal Tract Coats of Eyeball  Termination: LMN in the spinal cord (contralateral to the origin in the cerebral 1. Fibrous Coat cortex) − Protects the delicate inner structure of the eye and with the intraocular pressure maintain the shape and turgor of the eyeball Corticobulbar tract a. Sclera - posterior 5/6 - opaque, white of the eye Origin: Broadmann’s area 4 and 8 (Cerebral Cortex) b. Cornea - Anterior 1/6 - Transparent  Descend on the ipsilateral side of the midbrain, pons and medulla  Corticobulbar fibers synapse Sclera  Termination: Cranial motor nuclei in the brainstem of both sides ( R&L) except − the outermost coat those for lower face and tongue which are supplied contralaterally only − also called the fibrous tunic seen anteriorly as the “white of the eye” − covered in the anterior part by the transparent conjunctiva Clinical correlation − densely packed collagenous fibers (type I collagen fibrils) – where tendons of A. Upper motor neuron lesion – occurs when there is damage to the pyramidal tract extraocular muscles are attached along its path − pierced by optic nerve, ciliary nerves and blood vessels Manifestations: Cornea  Spastic paralysis − The central transparent anterior portion of the eye covering the colored part  Hyperreflexia of the eye which is the iris  Positive Babinski sign − One of the few organs that can be successfully transplanted from one person  Atrophy from disuse only to another without the worry of rejection because it has no blood vessels thus  Negative fasciculations it is beyond the reach of the immune system B. Lower motor neuron lesion - involves the anterior horn cells of the spinal cord − Avascular and the central part depends on diffusion from aqueous humor for and the motor nuclei of cranial nerves its nourishment. Manifestations: − Thicker than sclera with refractive power 2x as high as the lens.  flaccid paralysis 2. Vascular and Muscular coat or UVEA  Hyporeflexia − Concerned with nutrition of retina and production of aqueous humor  Negative Babinski sign − Provides mechanisms for accommodation of the eyes for near vision and  Marked atrophy control of amount of light entering the eye  Positive fasciculations and fibrillations a. Choroid – most of the blood vessels are located on choroid b. Ciliary body – secretes aqueous humor B. EXTRAPYRAMIDAL SYSTEM c. Iris − Network of interconnections of various parts of cerebral cortex and several subcortical centers ( including thalamus, basal ganglia, and cerebellum ) with Constrict - Increase in light ; Relax - decrease in light major pathways to spinal motor neurons arising from reticular formation Functions: Choroid 1. Regulation of actions of pyramidal system for smooth coordinated − Middle coat of the eye movements. − Blood-rich nutritive tunic that contains a dark pigment that prevents light from 2. Production of automatic movements (smiling, gesticulating) the scattering inside the eye 3. Production of unconscious adjustment in postures and muscle tone Ciliary Body − A thickening of the vascular tunic SPECIAL SENSES − Connects choroid with the circumference of the iris − With ciliary muscle for accomnodation VISUAL SENSE / APPARATUS − When ciliary muscle contracts, the lens become more convex o Each eyeball is positioned in a bony depression in the skull called orbit − Accomnodation - The ability of the eye focus specifically for close objects o Only the anterior one-sixth of the eye’s surface can normally be seen o Made up of the eyeball specialized for its ability to react to light − Less 20 ft. mapapagod yung mata; more than 20 ft. mag rerelax yung mata Eyeball − With ciliary processes producing aqueous humor − the stimuli for sense of vision, the light rays must pass through the different parts of the refractive media before reaching the retina. Glaucoma – eye disease can cause vision loss if you are diabetic − These are the following: Iris a) cornea c) lens − Heavy pigmented colored part of the eye which is membranous extension of b) aqueous humor d) vitreous humor the choroid − Partially covers the lens, leaving around opening at the center called pupil Accessory structures of the eye – protects, lubricate, move the eye − With sphincter and dilator pupillae (constrict and dilate pupils) 1. Extrinsic Eye Muscles − Like the diaphragm of the camera; it can increase or decrease the diameter of 2. Eyelids - controlled by orbicularis oculi its aperture (the pupil) to admit more or less light 3. Conjunctiva - transparent covering of the eyeball − Constriction of the pupils is produced by contraction of the circularly arranged 4. Lacrimal apparatus fibers within the iris supplied by parasympathetic, dilation is produced by contraction of the radially arranged fibers supplied by sympathetic Eyelids 2 smooth muscles: a. Sphincter pupillae − Anteriorly the eyes are protected by the eyelids which meet at the medial and lateral corners of the eye, the medial and lateral canthus respectively − Circumferentially oriented fibers − Blinking – occur 20 times per minute − Constriction of pupil (parasympathetic) − Eyelashes - Projecting from the border of each eyelid − Constriction - miosis b. Dilator pupillae − Meibomian Glands − Modified sebaceous glands associated with the eyelid edges − Radially oriented fibers − Produce an oily secretion that lubricates the eyes − Dilation of pupil (sympathetic) − Ciliary Glands − Dilation - mydriasis − Modified sweat glands between the eyelashes Conjunctiva 3. Nerve Coat a. Retina − Lines the eyelids and covers part of the white eye (sclera) infront − Innermost layer where receptors for sense of sight are found − Secretes the mucus which helps to lubricate the eyeball and keep it moist Lacrimal Glands − The nervous coat of the eyeball containing the photoreceptor cells TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) o Fibers from the optic chiasm going to the lateral geniculate bodies are called optic A. Photoreceptor tract a. Rods o Lateral geniculate bodies are the last relay station of the visual pathway o stimulated by low intensity light o Cells from the lateral geniculate bodies project fibers to the primary visual area o For night vision (scotopic vision) and are called optic radiation or geniculocalcarine tract o Contains reddish pigment o Termination of the visual pathway is at the calcarine area, the primary visual area o Rhodopsin – very sensitive and produces detachable signal on absorption (Brodmann’s area 17) of a single photon of light o Night blindness – vitamin a deficiency Lesion Clinical Manifestation b. Cones (Visual Field Defect) o stimulated by high intensity light Right Optic Nerve Anospia/Blindness of the right eye o For day vision/ color vision (photopic vision) sensitive to blue, green, and Lateral Optic Chiasm Binasal Heteronymous Hemianopsia Medial Optic Chiasm Bitemporal Heteronymous Hemianopsia red lights – 3 kinds provide basis for color vision R Optic Tract L Homonymous hemianospia B. Refractive Media of the Eyes R Optic radiation − Transparent structures traversed by the light rays on the way to the R Calcarine area photoreceptors of the retina − These structures can bend or refract the light rays so the images can be Functions of the eye focused on the retina. o Functions like a camera. o Pupil allows light into the eyes, which focused by the cornea 1. Cornea o The light striking the photoreceptors of the retina produces action potentials within 2. Aqueous humor (water) (in anterior and posterior chamber) the visual pathway 3. Lens o The optic nerve conveys these action potentials to the brain where perception 4. Vitreous humor occurs Lens − transparent biconvex body situated immediately behind the pupil. AUDITORY SENSE / APPARATUS − shape changes during accommodation Parts of the ear − covered by a homogenous highly refractile capsule which is essentially an 1. Outer (external) ear exceedingly thick basal lamina − Pinna or auricle Vitreous humor − External acoustic meatus − colorless, structureless. gelatinous mass with a glasslike transparency filling up the − Tympanic Membrane or Eardrum vitreous cavity between lens and retina. − nearly 99% is water Pinna or Auricle − with liquid and solid phase. o Shell-shaped structure surrounding the auditory canal opening Pars Optica External Auditory Canal − photosensitive area o A short narrow chamber about 1 inch long by ½ inch wide − with a circular depressed white area, optic disk or optic papilla where optic nerve o Curved into temporal bone of the skull exits and retinal vessels enter and leave o Skin of walls lined with ceruminous glands which secretes a waxy yellow substance Optic Disk called ear wax, or cerumen − contains nerve fibers but no photoreceptors and is insensitive to light. Called Tympanic Membrane or Eardrum physiologic blind spot. o A thin membrane separating outer from middle ear − 2.5 cm lateral to optic disk is a small oval yellow area Macula Lutea with central depressed area Fovea Centralis. This is the area of most acute vision. 2. Middle ear (tympanic cavity) − Characterized by presence of cones and neural element greater than elsewhere. − Ossicles (malleus, incus stapes) This is a rod free area − Tensor tympani, stapedius Cuneus gyri – lies on the superior bank of the calcarine cortex, receives the medial Middle Ear or Tympanic Cavity fibers of the visual radiations. − A small, air filled cavity within the temporal bone Lingual gyrus – lies on the inferior bank of the calcarine cortex, the medial fibers a. Medial Boundary coursing in the visual radiations, which carry input from the upper retina (i.e. the lower o A bony wall with 2 openings: contralateral visual field), pass from the lateral geniculate body directly through the 1. Oval window parietal lobe to reach the cuneus gyrus. 2. Round window When light passes from one substance to another substance that has a different b. Lateral Boundary density, its speed changes and its rays are bent, or refracted o Tympanic membrane with handle of the malleus attached Light rays are bent in the eye as they encounter the cornea, aqueous humor, lens, c. Anterior Boundary and vitreous humor o Eustachian tube (connects middle ear and nasopharynx) The refractive or bending power of the cornea and humors is constant d. Posterior Boundary However, that of the lens can be changed by changing its shape – that is by making o Mastoid process it more or less convex, so that light can be properly focused on the retina The greater the lens convexity, or bulge, the more it bends the light Ossicles in the Middle Ear On the other hand, the flatter the lens, the less it bends the light o Malleus (hammer) − attached to tympanic membrane The resting eye is “set” for distant vision o Incus – anvil In general light from a distant source o Stapes – stirrups, presses on the oval window of the inner ear (over 20 ft) approaches the eye as parallel rays, and no change in lens shape is 3. Inner (internal) ear (labyrinth) necessary for it to be focused properly on the retina Composed of 2 parts: However , light from a close object tends to scatter and to diverge, or spread out , A. Bony Labyrinth and the lens must be bulge to make close vision possible o Wall is bony – temporal bone To achieve this , the ciliary body contracts allowing the lens to become more o Fluid inside is perilymph (one of the two types of cochlear fluids, the other convex. being endolymph) Electrical signals pass from the photoreceptors (rods and cones) to the bipolar cells Made up of: and then to the ganglion cells − Cochlea – made up of scala vestibuli and tympani; concerned with hearing Axons of ganglion cells join together and pierce the back of the retina (optic disc) − Vestibule – concerned with static equilibrium to form the optic nerve − 3 semicircular canals – concerned with dynamic equilibrium B. Membranous Labyrinth Myopia – nearsightedness; corrects with concave o Found inside the bony labyrinth Hyperopia – farsightedness; corrects with convex o Wall is fibrous o Fluid inside is endolymph (fluid contained in the membranous labyrinth of the Visual Pathway inner ear) o Optic nerve has nasal fibers ( from the medial side) and temporal fibers (from the Made up of: lateral side) − Scala media – inside bony cochlea o Nasal fibers receive impulse from the temporal visual field and the temporal fibers − Utricle & Saccule – inside bony vestibule receive impulse from the nasal visual field − 3 semicircular ducts – inside the semicircular canal o Nasal fibers decussate at the level of the optic chiasm while temporal fibers leave Organ of Corti the optic chiasm without decussating o Receptor for hearing TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) o Found in the cochlea − vestibule and the semicircular canals are components of the bony labyrinth associated with balance Cochlea Receptors: − A spiral bony canal turning 2 ¾ around a central bony axis (modiolus) 1.Cristae Ampullaris − A spial bony projection from modiolus (spiral lamina) makes also a 2 ¾ turns. o found in the dilatations of semicircular ducts called ampulla − Scala vestibuli and tympani contain perilymph. They communicate in heliotrema o stimulated by angular acceleration − Scala media contains endolymph o contains gelatinous substance called cupula Incompletely divides the bony cochlea 2.Macula 1. Scala vestibuli o found in the vestibule 2. Scala tympani o stimulates by linear acceleration o contains gelatinous substance called otolithic membrane Tectorial membrane o containing otoconia, which are calcium carbonate crystals Dynamic Function − Composed of five filaments embedded in gelatinous matrix rich in o Mediated largely by the semicircular canals mucopolysaccharides o Can detect motion of head in space − Secreted at the upper surface of interdental cells Static Functions o Mediated mostly by the utricle Mechanism of hearing o Allow detection of the position of the head in relation to gravity Within the membranes of the cochlea is the organ of corti containing the hearing o Important in control of posture receptors or hair cells Sound waves that reach the cochlea through the vibrations of the eardrum ossicles Chambers of Vestibule and oval window set the cochlea fluids into motion 1. Utricle – largest membranous component of the vestibular system Receptor cells resting on the basilar membrane, the organ of corti are stimulated 2. Saccule − spherical and smaller communicates with the cochlear duct through the when these hairs are bent or tweaked by the movement of the gel-like tectorial short narrow ductus reunions and with the utricle through the utriculo-saccular duct. membrane that lies over them 3. Endolymphatic duct – tubular evagination of the utriculo-saccular duct ; it Once stimulated, the hair cells transmit impulses along the cochlear nerve to the terminates as a blind expansion called the endolymphatic sac auditory cortex in the temporal lobe the primary auditory area (Brodmann’s Area 41) Vestibular Nuclei 1. Superior – vestibular nucleus of Bechterew Deafness 2. Inferior – descending spinal − Hearing loss of any degree 3. Medial – vestibular nucleus of Schwalbe 2 types of deafness 4. Lateral – vestibular nucleus of Deither 1. Conduction Deafness 2. Sensorineural Deafness − Will have ascending fibers synapsing with somatic motor neurons of cranial nerve III, IV and VI for movement of eyeballs Conduction Deafness − Will have descending fibers to the spinal cord controlling the anti gravity muscles − Temporary or permanent − Results when something interferes with conduction of sound vibrations to the OLFACTORY SENSE / APPARATUS fluids of the inner ear Receptor: olfactory epithelium located in the upper 1/3 of each nasal mucosa Involves diseases of external and middle ear When receptors are stimulated by chemicals (chemoreceptor) dissolved in the − Impacted Cerumen mucus, they transmit impulses along olfactory cortex in the temporal lobe − Otosclerosis (uncus- Brodmann’s Area 34) − Rupture of Eardrum Olfactory pathway is closely tied with the limbic system (emotional-visceral part − Otitis Media of the brain) thus, olfactory impressions are long-lasting and very much part of our memories and emotions Sensorineural Deafness For example, the smell of chocolate chip cookies may remind you of our − Results from degeneration or damage to receptor cells to cochlear nerve, or to grandmother or the smell of perfume may remind you of your boyfriend neurons of auditory cortex The olfactory receptors are exquisitely sensitive – just a few molecules can Factors activate them − Old age Just like the auditory receptors, the olfactory neurons tend to adapt rather quickly − Extended listening to excessively loud sounds when they are exposed to an unchanging stimulus, in this case, an odor − Intake of ototoxic drugs like streptomycin, quinine, aspirin This is why a woman stops smelling her own perfume after a while but will quickly pick up the scent of another perfume on someone else Test to distinguish sensorineural from conduction deafness Certain chemicals activate the trigeminal nerve (CN V) as well as the olfactory 1.Weber’s Test nerve (CN I) and cause a particular reaction. 2.Rinne’s Test Pepper for example may cause sneezing, onions cause the eyes to water, and smelling salts (ammonium salts) initiate respiratory reflexes and are used to Weber’s Test revive people who are unconscious − The base of the vibrating tuning fork is applied in the midline Result for: GUSTATORY SENSE / APPARATUS 1.Normal Individual - sound appears to be in the midline Receptors: taste buds 2.Conduction Deafness - sound appears louder in the affected ear Taste Buds 3.Sensorineural Deafness - sound appears louder in the normal ear o Most are localized in the tongue o A few are found on the soft palate, inner surface of the cheeks, walls of Rinne’s Test oropharynx − The base of the tuning fork is placed over the mastoid process of the skull o Cylindrical taste bud is composed of many sensory gustatory cells that are − When it can no longer be heard, it is removed and then is held in front of the ear encapsulated by supporting cells Result for: o are found on the sides of the circumvallate and on the more numerous fungiform 1.Normal Individual - continues to hear by air conduction after bone conduction papilla ceases; air conduction is greater than bone conduction Taste Pore 2.Conduction Deafness - bone is greater than air conduction o Opening in the taste buds where the gustatory hairs (sensitive portion of receptor 3.Sensorineural Deafness - both are diminished but air conduction remains better cell) pass through than bone conduction o Dorsal surface of tongue is covered with small peg-like projections or papillae Four types of Papillae VESTIBULAR SENSE / APPARATUS 1. Circumvallate – with taste buds − Consists of receptors located in the inner ear on both sides of the head 2. Fungiform – with taste buds − 8th cranial nerve transmits the vestibular information (for equilibrium) from the 3. Foliate – with taste buds receptors to the CNS 4. Filliform – contains only gustatory cells Functions: 1.Maintains body balance Molecules dissolved in saliva at the surface of the tongue interact with the receptor 2.Coordinates eye, head and body movements cells, which in turn stimulates the sensory nerve endings that innervate the taste buds 3.Permits the eyes to remain fixed on a point in space as the head moves Taste buds on the anterior 2/3 of the tongue are innervated by the facial nerve (CN Vestibule Organs VII) Taste buds on the posterior 1/3 of the tongue innervated by glossopharyngeal nerve (CN IX) TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) Taste buds on the soft palate and the oropharynx are supplied by the vagus nerve − has a vasopressor effect hence also called vasopressin − raises blood pressure by constricting arterioles 4 basic modalities of taste are sensed acutely In particular regions of the tongue Pineal Gland 1.Sweet – tip of tongue − also called epiphysis cerebri or conarium 2.Bitter – back of tongue − a small organ, 6-8 mm long located at the caudal end of the diencephalon of 3.Salty – over most of the tongue the brain. 4.Sour – sides of tongue − consists of cells called pinealocytes − Hormones secreted: Melatonin derived from serotonin, which may promote Sweet Receptors sleepiness o respond to substances such as sugars, saccharine, and some amino acids Thyroid Gland Bitter Receptors − a lobulated gland lying in front of the neck at the upper part of the trachea o respond to alkaloids − there are 2 lobes connected at the midline by the isthmus Salty Receptors − Also secretes thyrocalcitonin secreted by the parafollicular cells which o respond to metal ions in solution helps regulate calcium Sour Receptors − homeostasis o respond to hydrogen ions (h+), or the acidity of the solution − Contains follicles, which secrete 2 thyroid hormones: thyroxine (T4) and triiodothyronine (T3) Termination of the gustatory pathway Actions of the thyroid hormones: o area located in the opercular part of the post central gyrus (Brodmann’s Area 43) 1.increase basal metabolic rate 2.helps maintain normal body temperature − histologically, it is formed by various follicles of different sizes and shape lined by simple cuboidal cells containing colloid material containing thyroglobulin ENDOCRINE SYSTEM − between capillaries are dense capillary network supported by reticular fibers − Endocrine Glands − magsesecrete si calcitonin/thyrocalcitonin kung mataas un calcium mo o It is also called the ductless glands. (hypercalcemia). Sila un magpapadecrease ng calcium level mo. o responsible for the synthesis and secretion of chemical messenger known as − Pinapababa nya un calcium, by inhibiting osteoclast activity (bone destroying hormones which are disseminated throughout the body via the bloodstream where cells) they act on specific target organs. Parathyroid Gland o the secretory cells release their hormones into the interstitial space from which they − are small oval endocrine glands closely associated posteriorly with the thyroid are rapidly absorbed into the circulation. gland o Unlike exocrine glands, endocrine glands have no duct system and therefore − supplied by inferior thyroid artery sometimes called the ductless glands. − secretes parathormone, which directly elevate blood calcium levels o Endocrine organs are highly vascular and you have blood vessels that are − if your calcitonin will decrease your calcium level, your parathormone will fenestrated (there are holes for the passage of large molecules) increase your calcium level. Types of Endocrine Glands − usually there are: Pituitary Gland o 2 superior parathyroid glands − also known as Hypophysis or Hypophysis Cerebri o 2 inferior parathyroid glands − a specialized appendage of the brain which secretes several hormones. Adrenal (Suprarenal) Gland − small slightly elongated gland approximately 1 cm in diameter situated in the − small flattened endocrine glands closely applied to the upper pole of the Sella turcica of the sphenoid bone and it is connected to the base of the brain kidneys via the infundibulum or stalk. 2 components of the adrenal gland: − Pea shaped structure measuring 1-1.5 cm in diameter 1. Adrenal Cortex − formerly regarded as the master gland because it influences the rest of the − outer and thicker portion endocrine glands; however, the hypothalamus regulates the function of the − 3 layers of cell: zona glomerulosa, zona fasciculata and zona anterior lobe of the pituitary gland hence this was regarded untrue reticularis Divisions of the Pituitary Gland − Secretions: I. Anterior Pituitary a. Mineralocorticoids (aldosterone and deoxycortisones) − also called the adenohypophysis − regulate fluids and electrolytes − makes up 75% of the total weight of the gland − help adjust blood pressure and blood volume − arises as an epithelial outgrowth from the roof of the primitive oral cavity b. Glucocorticoids (e.g. cortisone) known as the Rathke’s pouch − regulate metabolism and resistance to stress − secreting the hormones c. Androgens Hormones secreted by Anterior Pituitary: − promote libido in females and are converted to estrogen, 1.Growth hormones – long bones − also stimulate growth of axillary and pubic hairs in boys and girls 2.Thyroid stimulating hormone – thyroid gland and contribute to the prepubertal growth spurt 3.GnRh (follicles stimulating hormone, luteinizing hormone) – testis and 2. Adrenal medulla ovary − Secretes the catecholamines – epinephrine and norepinephrine 4.Prolactin – mammary gland for milk production. − Produces effects that enhance those of the sympathetic division of the 5.ACTH (adrenocorticotrophic hormone) – adrenal glands/cortex autonomic nervous system during stress 6.MSH (melanocyte stimulating hormone) – skin II. Posterior Pituitary 1.Increase blood K levels or decreased blood Na levels cause the adrenal − also called neurohypophysis cortex to increase the secretion of aldosterone into the general − derived from downgrowth of nervous tissue from the hypothalamus to which circulation. it remains joined by the pituitary stalk 2.A decrease in blood pressure is detected by the kidneys. In response, − coming from the floor of diencephalon. they increase the secretion of renin into the general to angiotensin I. a − It will just store the hormones that will come from hypothalamic nuclei. converting enzyme changes angiotensin I to angiotensin II, which − the neurohypophysis does not synthesize hormones. Instead stores and causes constriction of blood vessels, resulting in increased blood releases two hormones pressure. − Secretions from this lobe are produced by the cell bodies of the supraoptic 3.Angiotensin II causes increased secretion of aldosterone, which nucleus (produces vasopressin or ADH) and the paraventricular nucleus primarily affects the kidneys. (produces oxytocin) of the hypothalamus and are moved by axonal transport 4.Aldosterone stimulation of the kidneys causes Na retention, K to the axon terminals in the posterior pituitary excretion and decreased water loss. Hormones stored by Posterior Pituitary: Pancreas 1.ADH (antidiuretic hormone, Vasopressin) –kidney tubules − pistol shaped flattened organ, the head part of which is enclosed by the 2.Oxytocin (pitocin) – smooth muscle of uterus for contraction; mammary gland for duodenum, the body at the back of stomach and tail related with spleen milk let down or milk ejection. − not only exocrine gland but also has important endocrine functions Pituicytes − the endocrine portion is the Islets of Langerhans − modified neuroglial cells found in the pars nervosa believed to store and release 2 − the exocrine portion is secretion of enzymes. hormones: − pancreatic islets vary in size and most numerous at the tail of the pancreas a. Pitocin (oxytocin) Cells in the Islets of Langerhans − Stimulates uterine contraction 1.Alpha Cells − stimulates milk ejection (milk “letdown) from the mammary glands in response − less numerous containing acidophilic granules. to the mechanical stimulation provided by the suckling infant − found at the periphery of the islet and secrete glucagon – which b. Pitressin or ADH increases blood sugar − increases water reabsorption at the distal convoluted tubules of the kidneys. TRANSCRIBED BY: EIZEL ABARENTOS | BSN 1 – Y1 – 8  ANAPHY AND PHYSIOLOGY (ANPH111) 2.Beta cells c. Plasma Electrocytes − found at the center of the islets − inorg