Sensory System PDF

SENSORY SYSTEM A. Eye Anatomy and Physiology 1. Sensory receptors - 70% are located in the eye, over 1 million nerve fibers per eye 2. External Structures a. Eyelids - protects; associated with ciliary and tarsal gland for lubrication...

SENSORY SYSTEM A. Eye Anatomy and Physiology 1. Sensory receptors - 70% are located in the eye, over 1 million nerve fibers per eye 2. External Structures a. Eyelids - protects; associated with ciliary and tarsal gland for lubrication b. Lacrimal Glands - produce tears; contains lysozyme (cleansing and protection) c. Conjunctiva - produces lubricating mucus; lines your eyelids and anterior eyeball d. Extrinsic Eye Muscles - 6 muscle control cross movements e. Lens - separate the aqueous humor in the anterior segment from the vitreous humor in the posterior segment of the eye 3. Internal Structures a. Fibrous Layer - sclera (white part of the eye); cornea (transparent that refracts light) b. Vascular Layer - choroid ciliary body and iris ; function: regulatory of light entry c. Sensory Layer - retina with receptors (rodes for dim light and cones for color vision) 4. Physiology of Vision a. Refracted - power of the cornea and humour are constant b. Accommodation - ability of the eye to focus on close subject 5. Visual Fields and visual pathways to the brain a. Optic Chiasma - site where medial fibers from each eye cross over to the opposite site of the brain b. Pathway of nerve impulses from the retina - optic nerve, optic chiasma, optic tract, thalamus, optic radiation, visual cortex in occipital lobe of the brain 6. Disorders a. Myopia - near sightedness; corrected with convex lenses b. Hyperopia - farsightedness c. Presbyopia - age related loss of lens elasticity d. Glaucoma - increased intraocular pressure from blocked aqueous humor drainage B. Eye Anatomy and Physiology Divided into: 1. External Ear - tympanic membrane (separates the 1 and 2) 2. Middle Ear 3. Internal Ear 1. External Ear - Auricle and External acoustic meatus; directs sounds to the tympanic membrane 2. Middle Ear a. Contains ossicles malleus, incus, stapes for sound amplification  b. Connection to the throat by the auditory tube to equalize pressure 3. Inner ear a. Cochlea (spiral organ of corti)- houses hair cells (hearing receptors) for hearing (additional note: if a construction worker is working for like how many years, he may experience deafness due to affectation of the hearing receptors) b. Vestibule and semicircular canals - detects static and dynamic equilibrium 4. Disorders a. Meniere’s Syndrome - vertigo, tinnitus, hearing loss b. Sensorineural Deafness - damage to hair cells or nerve pathways C. Taste and Smell 1. Taste a. Detected by taste buds located on papillae (fungiform, vallate) b. Five sensations: sweet, sour, salty, bitter, umami (meat) 2. Smell a. Olfactory receptors in nasal cavity respond to dissolved chemicals ENDOCRINE SYSTEM 1. Hormonal Regulation Relationship Function: stimulates the release of your hormones via the hypophyseal portal system a. Hypothalamus releases regulatory hormones (TRH: thyrotropin-releasing hormone) b. Pituitary secretes TSH, ACTH, GH, etc 2. Thyroid Gland a. Produces T3 and T4, regulating metabolism b. Disorders i. Hypothyroidism - slow t3, t4, fatigue and weight gain, cold intolerance, condition wherein the thyroid gland under produce your hormones; Drug: levothyroxine; synthetic form of t4 restoring normal metabolic function ii. Hyperthyroidism - fast t3, t4, weight loss, tachycardia 3. Adrenal Gland a. Cortisol - stress hormone; increases blood sugar and blood pressure b. Aldosterone - regulates sodium and potassium (primary mineralocorticoid that acts on your kidney, promotes sodium reabsorption and potassium excretion; sodium in, potassium out; and also regulations salt and balance in bloodstream) - Enzyme Renin - release by the kidney, triggered when there is low blood pressure; converts angiotensinogen to angiotensin 1 which is converted to angiotensin 2 (stimulates aldosterone release which increases bp) 4. Reproductive Hormones a. FSH and LH - regulates your gonadal functions b. Testosterone - promotes 2nd male characteristics  c. Estrogen and Progesterone - regulates female reproduction cycle d. Hormones in Breastfeeding i. Prolactin - milk production - mammary gland ii. Oxytocin - milk ejection; let down reflex by causing contraction of mammary duct; induction of labor 5. Key Concepts a. Stress response i. Short term - epinephrine and norepinephrine (fight or flight response) ii. Long term - Glucocorticoid and mineralocorticoids b. Hormonal Regulation i. ADH - h2o retention ii. Aldosterone - regulates sodium and potassium iii. Prolactin and Oxytocin - lactation c. Enzymes and Hormones in BP Control i. RAAS - R renin A angiotensin A aldosterone S system - maintains bp and fluid balance d. Disorders linked to hormonal imbalances i. Acromegaly - hypersecretion of growth hormone ii. Alcohols effect - inhibits ADH iii. Cushing's syndrome - excessive cortisol (leads weight gain, high bp, and thinning of skin) CARDIOVASCULAR SYSTEM 1. Heart Anatomy and Physiology Location: mediastinum 1. Heart Chambers - two atria (receiving chambers); two ventricles (pumping or discharging chambers) 2. Valves - prevents backflow of the blood in our heart (tricuspid, pulmonary, mitral or bicuspid, aortic) -Stroke Volume - vol of blood ejected by which ventricle in 1 contraction 3. Conduction System  a. SA node (heart’s pacemaker) > av node > bundle of his > right and left bundle branches > purkinje fibers b. Regulates heartbeat i. Systole - above, contraction ii. Diastole - below, relaxation 4. Circulatory Pathways a. Pulmonary circulation- oxygenates your blood b. Systemic Circulation - delivers oxygen rich blood to body tissues 5. Blood Flow (Adult) a. Superior and Inferior Vena cava > Right atrium > Tricuspid > Right ventricle > Pulmonary valve > Pulmonary artery > Lungs > Pulmonary veins > Left atrium > Mitral Valve > Left ventricle > Aortic Valve > Aorta 6. Blood a. RBCs - transport oxygen in 120 days b. WBCs - fight infections; neutrophils and lymphocytes i. Leukocytosis - elevated WBC count, more than 11 00 cells/ mm3; increase infection, inflammation, stress 7. + chemotaxis > WBC > inflammation or injury sites > immune system > target and repair damage areas efficiently a. Platelets - mediates clotting process (hemostasis), process of stopping the bleeding i. Steps: vascular spasms > Platelet Plug formation > Coagulation (final step, fibrinogen converted into fibrin) 8. Blood Type Compatibility a. Type A  i. Has: A antigen ii. Plasma Antibodies: Anti B iii. Can receive: a and o iv. Can donate: a and ab b. Type B i. Has: B antigen ii. Plasma Antibodies: Anti A iii. Can receive: B and O iv. Can donate: B and AB c. Type AB i. Has: A and B antigen ii. Plasma Antibodies: none iii. Can receive: any blood (universal recipient) iv. Can donate: only AB d. Type O i. Has: no a or b antigen ii. Plasma Antibodies: anti A and B iii. Can receive: o iv. Can donate: all blood types (universal donor) 9. RH Factor a. Positive - receive both positive and negative b. Negative - only negative Question: Rhogam - drug which is administered to the pregnant mother with rh (-) to prevent formation of anti rh antibodies; to prevent mother from harmful future pregnancies Hemolysis - mothers antibodies attack the baby’s rbc causing severe anemia and other complications Liver - clotting factors; blood coagulation Fetal blood loss percentage - >30% - severe shock > death 10. Disorders a. Anemia - low rbc or hemoglobin b. Leukocytosis - high wbc count c. Hemophilia - bleeding disorders; lack clotting factors (factor number 8) ; treat - plasma transfusion or direct injection of the missing clotting factors to prevent or control bleeding episodes RESPIRATORY SYSTEM 1. Key structures a. Upper tract - nasal cavity, pharynx, and larynx b. Lower Tract - trachea, bronchi, bronchioles, alveoli 2. Gas Exchange a. Occurs in alveoli via diffusion b. Regulated by medulla oblongata and pons Carbon dioxide - most important stimulus in breathing During inhalation - diaphragm contract Epiglottis function - prevents food and liquid from entering the trachea 3. Respiratory Volumes a. Tidal volume - normal breathing volume b. Vital capacity - maximum exhales after max inhalation Chemoreceptors - detect changes in blood oxygen and carbon dioxide and ph level; rate and depth of breathing 4. Surfactant - fatty molecule; alveoli = reduce surface tension and prevent alveolar collapse between breath; allows lungs to expand a. In newborns - normal respiratory rate = 40-80 cycles per min b. Adult - 12-20 cycles per min 5. Disorders a. Asthma - airway inflammation and constriction b. Pneumothorax - air in pleural space and lung collapse c. Adenocarcinoma - lung cancer URINARY SYSTEM Location: kidneys are located along the dorsal body wall; retroperitoneal Function : filter waste products, from the blood, regulate blood volume pressure and electrolyte balance 1. Kidney Anatomy and Function a. Functional Unit - nephron (Filtration, Reabsorption, Secretion, Elimination ) b. Processes i. Filtration - glomerulus (network of capillaries that filters blood plasma allowing water and small molecules to pass in the bowman's capsule for further processing) ii. Reabsorption - proximal (convoluted) tubule reabsorbs water, glucose and ions iii. Secretion - removes hydrogen ions and toxins; involves active transport of waste product such as potassium and hydrogen from the blood into the nephron for excretion of urine c. Urinary bladder  i. Trigone - triangular region at the base of your urinary bladder define by the two opening so the 2 ureter and urethra ii. Urine transport - ureter - tube that carries urine to from the kidneys to urinary bladder for storage d. Urethral Sphincter - involuntary muscle that controls the release of urine from the bladder remaining close from leakage e. Thirst mechanism - primary driver for water intake trigger when the body detects dehydration or increase in blood osmolarity f. Kidney response to pH changes - relationship is between lungs and kidneys; so when blood rises which is alkaline = kidneys both secrete hydrogen ions into the urine and by that it reabsorbs bicarbonate ions to help lower the urine ph g. Loop of Henle - creates osmotic gradient in kidney medulla which is crucial for concentrating urine and conserving water 2. Hormonal Regulation a. ADH - increases water reabsorption in kidneys b. ALdosterone - promotes sodium retention and potassium excretion 3. Disorders a. UTI - bladder and urethra affectation b. Kidney stones - crystallized minerals that causes obstruction > obstruction c. Hypospadias - urethral opening is undersides d. Urethritis - inflammation of urethra LYMPHATIC AND IMMUNE SYSTEM 1. Lymphatic System a. Functions: i. Returns interstitial fluid to bloodstream (take note: swelling and impaired material exchange within tissues that leads to edema = abnormal accumulation) ii. Filters lymph via lymph nodes (x bacteria, foreign substances, tumor cells and part of immune system ) iii. Houses immune cells (take note: interferons - small proteins secreted by virus infected cells; cytotoxic t cells directly kill foreign cells) (neutralization - occurs when your antibodies bind to bacterial toxins preventing them from causing harm to your body; defense mechanism of immune system) b. Key organs i. Thymus - maturation of T cells ii. Spleen - filters blood and removes old RBC c. Immune Responses i. Innate immunity - first line (skin membrane example) ii. Adaptive immunity - T cells (cell mediated immunity); B cells (antibody production) d. Disorders i. Autoimmune Diseases - immune system attacks own tissues ii. Allergies - Hypersensitivity to antigens (treatment: antihistamines = blocks the effect of histamine which is release during allergic reaction)