Disorders of the Special Senses

What is a Plant Cell? Plant cells are eukaryotic cells that vary in several fundamental factors from other eukaryotic organisms. Both plant and animal cells contain a nucleus along with similar organelles. One of the distinctive aspects of a plant cell is the presence of a cell wall outside the cell membrane. Plant Cell Structure Just like different organs within the body, plant cell structure includes various components known as cell organelles that perform different functions to sustain itself. These organelles include: Cell Wall It is a rigid layer which is composed of polysaccharides cellulose, pectin and hemicellulose. It is located outside the cell membrane. It also comprises glycoproteins and polymers such as lignin, cutin, or suberin. The primary function of the cell wall is to protect and provide structural support to the cell. The plant cell wall is also involved in protecting the cell against mechanical stress and providing form and structure to the cell. It also filters the molecules passing in and out of it. The formation of the cell wall is guided by microtubules. It consists of three layers, namely, primary, secondary and the middle lamella. The primary cell wall is formed by cellulose laid down by enzymes. Cell membrane It is the semi-permeable membrane that is present within the cell wall. It is composed of a thin layer of protein and fat. The cell membrane plays an important role in regulating the entry and exit of specific substances within the cell. For instance, cell membrane keeps toxins from entering inside, while nutrients and essential minerals are transported across. Nucleus The nucleus is a membrane-bound structure that is present only in eukaryotic cells. The vital function of a nucleus is to store DNA or hereditary information required for cell division, metabolism and growth. 1. Nucleolus: It manufactures cells’ protein-producing structures and ribosomes. 2. Nucleopore: Nuclear membrane is perforated with holes called nucleopore that allow proteins and nucleic acids to pass through. Plastids They are membrane-bound organelles that have their own DNA. They are necessary to store starch and to carry out the process of photosynthesis. It is also used in the synthesis of many molecules, which form the building blocks of the cell. Some of the vital types of plastids and their functions are stated below: Leucoplasts They are found in the non-photosynthetic tissue of plants. They are used for the storage of protein, lipid and starch. Chromoplasts They are heterogeneous, colored plastid which is responsible for pigment synthesis and for storage in photosynthetic eukaryotic organisms. Chromoplasts have red-, orange- and yellow-colored pigments which provide color to all ripe fruits and flowers. Central Vacuole It occupies around 30% of the cell’s volume in a mature plant cell. Tonoplast is a membrane that surrounds the central vacuole. The vital function of the central vacuole apart from storage is to sustain turgor pressure against the cell wall. The central vacuole consists of cell sap. It is a mixture of salts, enzymes and other substances. Golgi Apparatus They are found in all eukaryotic cells, which are involved in distributing synthesized macromolecules to various parts of the cell. Ribosomes They are the smallest membrane-bound organelles which comprise RNA and protein. They are the sites for protein synthesis, hence, also referred to as the protein factories of the cell. Mitochondria They are the double-membraned organelles found in the cytoplasm of all eukaryotic cells. They provide energy by breaking down carbohydrate and sugar molecules, hence they are also referred to as the “Powerhouse of the cell.” Lysosome Lysosomes are called suicidal bags as they hold digestive enzymes in an enclosed membrane. They perform the function of cellular waste disposal by digesting worn-out organelles, food particles and foreign bodies in the cell. In plants, the role of lysosomes is undertaken by the vacuoles. Chloroplasts It is an elongated organelle enclosed by phospholipid membrane. The chloroplast is shaped like a disc and the stroma is the fluid within the chloroplast that comprises a circular DNA. Each chloroplast contains a green colored pigment called chlorophyll required for the process of photosynthesis. The chlorophyll absorbs light energy from the sun and uses it to transform carbon dioxide and water into glucose. Structure of Chloroplast Chloroplasts are found in all higher plants. It is oval or biconvex, found within the mesophyll of the plant cell. The size of the chloroplast usually varies between 4-6 µm in diameter and 1-3 µm in thickness. They are double-membrane organelle with the presence of outer, inner and intermembrane space. There are two distinct regions present inside a chloroplast known as the grana and stroma. • Grana are made up of stacks of disc-shaped structures known as thylakoids or lamellae. The granum of the chloroplast consists of chlorophyll pigments and are the functional units of chloroplasts. • Stroma is the homogenous matrix which contains grana and is similar to the cytoplasm in cells in which all the organelles are embedded. Stroma also contains various enzymes, DNA, ribosomes, and other substances. Stroma lamellae function by connecting the stacks of thylakoid sacs or grana. The chloroplast structure consists of the following parts: Membrane Envelope It comprises inner and outer lipid bilayer membranes. The inner membrane separates the stroma from the intermembrane space. Intermembrane Space The space between inner and outer membranes. Thylakoid System (Lamellae) The system is suspended in the stroma. It is a collection of membranous sacs called thylakoids or lamellae. The green colored pigments called chlorophyll are found in the thylakoid membranes. It is the sight for the process of light-dependent reactions of the photosynthesis process. The thylakoids are arranged in stacks known as grana and each granum contains around 10-20 thylakoids. Stroma It is a colorless, alkaline, aqueous, protein-rich fluid present within the inner membrane of the chloroplast present surrounding the grana. Grana Stack of lamellae in plastids is known as grana. These are the sites of conversion of light energy into chemical energy. Chlorophyll It is a green photosynthetic pigment that helps in the process of photosynthesis. Functions of Chloroplast Following are the important chloroplast functions: • The most important function of the chloroplast is to synthesize food by the process of photosynthesis. • Absorbs light energy and converts it into chemical energy. • Chloroplast has a structure called chlorophyll which functions by trapping the solar energy and is used for the synthesis of food in all green plants. • Produces NADPH and molecular oxygen (O 2 ) by photolysis of water. • Produces ATP – Adenosine triphosphate by the process of photosynthesis. • The carbon dioxide (CO2) obtained from the air is used to generate carbon and sugar during the Calvin Cycle or dark reaction of photosynthesis. Mitochondria “Mitochondria are membrane-bound organelles present in the cytoplasm of all eukaryotic cells, that produce adenosine triphosphate (ATP), the main energy molecule used by the cell.” What are Mitochondria? Popularly known as the “Powerhouse of the cell,” mitochondria (singular: mitochondrion) are a double membrane-bound organelle found in most eukaryotic organisms. They are found inside the cytoplasm and essentially function as the cell’s “digestive system.” They play a major role in breaking down nutrients and generating energy-rich molecules for the cell. Many of the biochemical reactions involved in cellular respiration take place within the mitochondria. The term ‘mitochondrion’ is derived from the Greek words “mitos” and “chondrion” which means “thread” and “granules-like”, respectively. It was first described by a German pathologist named Richard Altmann in the year 1890. Structure of Mitochondria • The mitochondrion is a double-membraned, rod-shaped structure found in both plant and animal cell. • Its size ranges from 0.5 to 1.0 micrometers in diameter. • The structure comprises an outer membrane, an inner membrane, and a gel-like material called the matrix. • The outer membrane and the inner membrane are made of proteins and phospholipid layers separated by the intermembrane space. • The outer membrane covers the surface of the mitochondrion and has a large number of special proteins known as porins. Cristae The inner membrane of mitochondria is rather complex in structure. It has many folds that form a layered structure called cristae, and this helps in increasing the surface area inside the organelle. The cristae and the proteins of the inner membrane aid in the production of ATP molecules. The inner mitochondrial membrane is strictly permeable only to oxygen and ATP molecules. A number of chemical reactions take place within the inner membrane of mitochondria. Mitochondrial Matrix The mitochondrial matrix is a viscous fluid that contains a mixture of enzymes and proteins. It also comprises ribosomes, inorganic ions, mitochondrial DNA, nucleotide cofactors, and organic molecules. The enzymes present in the matrix play an important role in the synthesis of ATP molecules. Functions of Mitochondria The most important function of mitochondria is to produce energy through the process of oxidative phosphorylation. It is also involved in the following process: 1. Regulates the metabolic activity of the cell 2. Promotes the growth of new cells and cell multiplication 3. Helps in detoxifying ammonia in the liver cells 4. Plays an important role in apoptosis or programmed cell death 5. Responsible for building certain parts of the blood and various hormones like testosterone and estrogen 6. Helps in maintaining an adequate concentration of calcium ions within the compartments of the cell 7. It is also involved in various cellular activities like cellular differentiation, cell signaling, cell senescence, controlling the cell cycle and in cell growth. Disorders Associated with Mitochondria Any irregularity in the way mitochondria function can directly affect human health, but often, it is difficult to identify because symptoms differ from person to person. Disorders of the mitochondria can be quite severe; in some cases, they can even cause an organ to fail.

[t comes from the GREEK name "Epilepsia" which means "taking hold of or seizing". - It is a disorder characterized by: recurrent seizures. SEIZURES R ectment transient attacks of: R epresent: R esult from: ASSOCIATED WITH: somatic, psychic, or, autonomic clinical featmes. clinical features of abnormally hyperexcitable cortical neurons. paroxvsmal and excessive electrical neuronal discharges. EEG changes & may be disturbance of consciousness. same causes of convulsions 1. Idiopathic epile~ • It is the commonest cause. no cause can be detected ( 65 % ) • It may be associated with positive family history in some cases. • It starts in the l st & 2nd decades in the form of: -- Grand ma! epilepsy. Petit mal epilepsy. Myoclonic epilepsy. Atonic seizures. 2. Secondary epilepsy A. Local causes in the brain: l. Congenital: 2. Traumatic: cerebral palsy. a cause can be detected cerebral contusion or laceration. 3. Inflammatory: 4. Neoplastic: 5. Degenerative: 6. Vascular: encephalitis, brain tumours. mening1t1s, presenile dementia. brain abscess. stroke (especially hemon-hagic), hypertensive encephalopathy. B. General causes with secondary effects on the brain: I. Toxic: 2. Iatrogenic: 3. Metabolic: 4. Endocrinal: 5. Organ failure: 6. Heart disease: 7. Nutritional: - Alcohol, cocaine, lead. - Lidocaine, INH. - j glucose & ! glucose. - Hypoparathyroidism. - Hepatic failme. - Adam's Stoke's attacks. - Pellagra. - Botulism, tetanus. - Ambilhar, Amphetamine, Aminophylline. - j Ca & ! Ca. - Hype1thyroid crisis. - Renal failure. - Fallot's tetralogy. - j Na & ! Na. - Vitamin B6 deficiency. 8. Physical: 9. HYSTERICAL. - High fevers. - Heat stroke. 136 137 CLINICAL PICTURE 1. GENERALISED SEIZURES " Excessive electrical discharges from cortical neurons in BOTH hemispheres simultaneously " I. II. 1. Grand Mal Epile~: 1. Pre-ictal stage "attacks of tonic-clonic convulsions " (aura) It is a warning sign of a coming attack. It may be: • Somatic: • Psychic: • Autonomic: 2. Ictal stage Myoclonus, Hallucinations. Tachycardia, (seizure) Sudden loss of consciousness: Parasthesias. Sweating. for seconds to minutes. -- Tonic phase (few seconds) o The UL & LL: o o o o The HEAD: The JAWS: CYANOSIS: are extended. is retracted to one side & the eye balls rolled up. are firmly clenched, with biting of the TONGUE. due to impaired respiration. There may be incontinence of urine. Clonic phase (few minutes) o The UL & LL: o The HEAD: 3. Post-ictal stage - It may be: • Somatic: • Psychic: • Autonomic: Drug of choice: contract & relax repeatedly & rapidly. jerks forcibly. (sequelae) Todd's paralysis(< 24 hours, due to neuronal exhaustion). Confusion. Vomiting. Carbamazepine (Tegretol) or Phenytoin (Epanutin) Petit Mal Epilepsy: "attacks of loss of consciousness " " Absence " It starts in childhood & improves at puberty & usually disappears at the age of 20. 2. It is NOT PRECEEDED by aura & NOT FOLLOWED by sequelae. 3. It is usually PRECIPITATED by: hyperventilation 4. It is characterized by: or photic stimulation. sudden loss of consciousness of short duration (few seconds). 5. It may be associated with: • High frequency ( 50 attacks / day). • Falling to the ground without warning. • Jerky movements of the head & UL Drug of choice: (myoclonic petit mal). Valproate (Depakine) or Succinimide (Zarontin) 137 138 Ill. M oclonic Seizures: "attacks of involuntary clonic movements " - It is characterized by: sudden, jerky, shock-like INVOLUNTARY muscle contraction. • The jerks are bilateral contractions, mainly of the shoulders and arms. • However, some patients repmtjerking in the lower limbs, trunk, or head. - It may be of 2 types: - Occurs singly • Simple: • As a pait of: I Drug of choice: IV. Atonic seizures: (no loss of consciousness). - Grand mal epilepsy (aura). - Petit mal epilepsy. Valproate (Depakine) or Clonazepam (Rivotril) I - Transient attacks of brief loss of postural tone, often resulting in falls and injuries. 2. PARTIAL SEIZURES "Excessive electrical discharges from cmtical neurons in a ce1tain area in ONE hemisphere" A. Simple seizures: " No disturbance in consciousness " - The CP depends on the site of the hyperexcitable neurones in the cerebral cortex, whether in: "Motor area or Senso,y areas". 1. Motor fits: • Focal fits: • Motor jacksonian fits: 2. General Sensory fits: • Focal fits: • Sensory jacksonian fits: 3. Special Senso1y fits: • Visual hallucinations: • Auditory hallucinations: • Olfactory hallucinations: B. Complex seizures: - SITE: movement of part of a limb or the whole limb. movement of one side of the body (see before). parasthesia of part of a limb or the whole limb. parasthesia of one side of the body (see before). irritation of the visual sensory area. irritation of the auditory sensory area. initation of the uncus. " disturbance in consciousness " The hyperexcitable neurons are in the Temporal lobe "Temporal lobe epilepsy". - DURATION: The seizure lasts few seconds to few minutes. - The seizure starts with A ura, followed by A bsence, Automatism, Amnesia: 1. 2. 3. 4. A ura: A bsence: Automatism: A mnesia: Olfactory hallucinations, Deja-vu phenomenon, Sensation of fear. Absent patient with staring eyes (with no response to conversation). Involuntary Purposeless acts: motor ( eg, lip smacking, chewing) or verbal. No recalling of the seizure. 138 139 3. PARTIAL SEIZURES ~ GENERALISED SEIZURES " Partial seizures may spread to involve the whole brain .- secondarily generalised seizures " . HY-sterical epilepsY • Usually: • The cause: • Incidence: young neurotic Sj2 . psychological & there is no organic lesion. usually occurs in the presence of people. • It is associated with: • EEG: • It is not associated with: normal. • Missed ttt. • Menses. • Alkalosis. anxiety, palpitaion & hyperventilation. tongue biting or incontinence of urine. • Alcohol use & Drug abuse ( e.g. cocaine ). • S timulation by photons & Hyperventilation. • S leep deprivation & Stress & sudden withdrawal of antiepileptic drngs. INVESTIGATIONS 1. EEG: • It is the most specific test for epilepsy because it records the electrical activity of the brain. • It shows specific pattern: 2. LOCAL INVESTIGATIONS: "Epilepsy waves". "CT & MRI of the brain" • To identify or exclude a LOCAL CAUSE of seizures in the brain. 3. GENERAL INVESTIGATIONS: "Laboratory investigations" • To search for a GENERAL CAUSE of seizures, e.g. blood glucose. 139 140 TREATMENT A. General Measures: 1. 2. Moderation of the patient's physical activity. A void the precipitating factors ( Alcohol, hyperventilation, photic stimulation ...... ). 3. A ketogenic diet is encouraged because it will induce acidosis: - Acidosis is beneficial as it raises the threshold of stimulation of the brain cells. B. Specific Treatment: 2. 1. Treatment of the cause in secondary epilepsy. Anti-epileptic drugs: a) Always sta1t with one drug, then add another drug if there is no response. b) Always stop the drugs ONLY if: • The patient stays free of symptoms for at least 2 years. • The patient has a normal EEG. 3. Side effects of Anti-epileptic drugs: I . Skin rash. 2. 3. Bone marrow depression. Ataxia. Drug 1. Barbiturates (Pbenonobarbitone) 2. Hydantoin (Epanutin) 3. Carbamazepine 4. Clonazepam 5. Valproate 6. Succinamide ANTI-EPILEPTIC DRUGS NEW ANTI-EPILEPTIC DRUGS - These drugs are new dtugs that may be used in resistant seizures. 1. Lamotrigine: 200 - 400 mg/ day. 2. Felbamate: 3. Gabapentin: 400- 800 mg/ day. 600 - 1200 mg/ day. \ " General rules for use ": Dose 100-600 mg I day 100-600 mg / day 200-600 mg I day 2-6 mg I day 500-1500 mg I day 500-1000 mg / day Best indicated - Broad spectrum. - Not for petit mal. - Grand mal. - Motor Jacksonian fits. - Grand mal. - Motor Jacksonian fits. - Complex seizures. - Not for petit ma!. - Myoclonic. - Grand mat. - Broad spectrum. - Petit mat. 140 141 STATUS EPILEPTICUS DEFINITION - A medical emergency: 1. Repeated attacks of generalized convulsions, with lack of recove,y of consciousness, 2. Persistent attack of seizure lasting for at least 30 minutes. OR, - If the convulsions are not stopped rapidly, coma deepens & death may occur due to: heart failure or respiratory failure or brain damage or hyperpyrexia. - The most common causes are: sudden withdrawal of anti-epileptic drugs & stroke. TREATMENT A. General Measures: l. Take care of: " ABC " • Place the patient on the ground, to guard against falling from bed. • Mouth gag & 02 inhalation ( endo-tracheal intubation may be needed). • Record the vital signs regularly. 2. Take a sample of: - Venous blood: for the level of: - A.tierial blood: for the level of: 3. a nti-epileptic drugs, a lcohol. pH, p0 2, pC02, HC0 3. Give cerebral dehydrating measures: e.g. Frusemide, cone. Mannitol, Dexamethazone. B. Specific Treatment: - Phenytoin with diazepam (or clonazepam) immediately: 1. Phenytoin: 2. Diazepam: Clonazepam: seizures recur: 15 mg I Kg slow infusion. 5 mg slowly IV, to be repeated after 5 minutes if seizures recur: maximum dose: 20 mg. OR: 2 mg slowly IV, to be repeated after 5 minutes if maximum dose: 6 mg. - If seizures persist after 20 min. of Phenytoin & diazepam: 3. PHENOBARBITONE: - In resistant cases: 200 mg infusion. 4. GENERAL ANAESTHESIA: may be used.

History of policing Pre-confederation Mostly informal policing by community residents First police officers Quebec city, mid 17th century Upper Canada, early 19th century Mandate Police conflicts between ethinc groups and employes/labours Maintain moral standards (drunkenness, alcoholism) Apprehend criminals Provincal Police Force Response to disorder resulting form gold strikes in 19th century Replaced by RCMP during 20th century Currently, Ontario,Quebec and parts of Newfoundland have their own provincal police force History of RCMP North-Wesr Mounted Police Founded in 1873 Maintain law and order Ensure orderly settlement in prairies Many problems: desertion, resignation and improper conduct Replaced by Royal Canadain Mounted Police Police Today About 70,000 police officers across Canada 199 police officers per 100,000 population Lower than Scotland (337), England(244), U.S (238) NUmber increased over past decade NUmber of female officers increased 1 out of 5 officers is a women Contemporary Policing Structure of policing Four levels Federal, Provincial, municipal, and First nations Also public transportation police (railway, airport, and transit) Some municipalities have own forces E.g, Peel, Toronoto Others use provincial force detachments or RCMP detachments Royal Candanin Mounted Police Governed by Royal Canadian Mounted Pollcei Act (1985) Broad Range of policing activities, including federal policing and international peacekeppiong Contract Policing Provincial, territorial and municipal level Concerns about local oversight and accountability In but not of communities-difficult to ensure that RCMp detachments are responsive to communities Provincial Police Three forces Ontario Provincial Police Surete du Quebec (SQ) Royal Newfoundland Constabulary (RNC) Other provinces contractually use the RCMP Responsibilities Police rural areas and areas outside municipalities Enforce provincial laws and Criminal Code Regional Police Amalgamated Forces E.g Peel region police and Halton Regional Police Force Provide Police Services to over Half of Ontarians Advantages Cheaper, more servies Disadvantages To centralized, not in touch with community Municipal Police Responsibilites Enforce Criminal Code, Provincal Statues, municipal by laws, some federal statues (e.g drugs) Largest number of officers of any level My be contracted to RCMP or Provincal force Costs are paid by the municipality First Nations Type of policing is negotiated by First Nations Commnity Autonomous reserve based First Nations Officers from RCMP or OPP Responsibilites Enforce Criminal Code, federal and provicanl statues, band bylaws Accountability Reserve based police commission or band council Private Security Services Two main types 1. Private Security Firms 2. Company based, in house security officers No more legal authority than ordinary citizens But can arrest and detain people who commit crimes on private property In Canada, Private security officers outnumber police officer by four to one Parapolice Extension of activities Lack of systems of oversight like transitional police Police Work POlicing The activities of any indivual or organization acting legally on behalf of public or private organizations or persons to maintain security or social order Pluralization of Policing The sharing between public and private security Legislative Framework Carry out tasks within a number of legislative frameworks, define role, powers/responsibilites Canadian charter of rights and freedoms- most impactful on power/actvites of police Provincial and municipal legislation - Status such as motor vehicle administration acts, highway traffic acts, liquor acts and provincial/musincpal police acts Democracy Governance Categories of Policing Recruitment and Training of police officers Police recruitment Recruiting Visible Minorites and Aboriginal People Special initvates and programs for youth, women and visible minorities PEACE (Police Ethnic and Cultureal Exchange) OPPBound (particpate in variety of activate with officer) Toronto POlice recruitment of Somali Officers Edmonton police uniforms that include a hijab Police Training Residential/non-residential academies, centralized and decentralized Physical and academic instruction, socilization into the police occupation Operational field traiing Hands-on application of principles learned in the academy Mentoship form senior officer Working Personality of Police officers Challenges of Police Work Work Enviroment Long hours and shift work Exposure to stressors, especially in high demand environments PTSD and burnout Work Organiztion Harassment of female officers Cumbersome of system of internal redress Summary A number of misconceptions arounds police work, including th emotion that most police work involves crime control A variety of influences on the roles and activities of the police Four levels of policing: federal, provincial, mnicipal and First Nations, each with different responsibilities

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