1st exam 224 Lecture.odt

Sense Organs Sensory receptors are any kind of structure that detects a stimulus Simple free nerve ending Heat or pain Complex structure Involves nerves and tissue to enhance the stimulus Ears, eyes, nose Job of sensory receptors Transduction – process of converting one form of energy into another....

Sense Organs Sensory receptors are any kind of structure that detects a stimulus Simple free nerve ending Heat or pain Complex structure Involves nerves and tissue to enhance the stimulus Ears, eyes, nose Job of sensory receptors Transduction – process of converting one form of energy into another. Sensory receptors of light, sound, touch Light comes in Hits receptors Tells nerve – signals This is what it is 2 stages of sensory process Sensation – receptors have to detect a stimulus Converts to a receptor potential If strong enough it will generate nerve impulse to the CNS (central nervous system) Perception – conscious knowledge or interpretation of the stimulus. Are you seeing, touching, hearing, feeling? Not everything gets to the brain Sensory receptors transmit four types of information Modality – what type of stimulus it is Vision, hearing, tasting Colors, bass/treble, sweet/salty Location – where it is coming from Receptive field 1 receptor will receive info for entire field Intensity – how loud/bright Stimulus intensify will increase when nerve firing increases More neurons are recruited Weak stimulus is only activating more sensitive neurons Brain knows intensity depending on neuron firing Duration – how long does stimulus last Sensory adaption If stimulus is prolonged the firing of the neuron slows down, not important Phasic receptors Very quickly adapting especially with continuous stimulation Bad smell that you get use to Tonic Receptors – keep responding and adapt slowly Recognizes pain Classification of receptors Modality Where stimulus starts Where they are located Modality Thermoreceptors Hot and cold Lots of these in skin Photoreceptors Eyes responding to light Nociceptors Pain receptors Skin, mucous membranes Thermoreceptors, chemoreceptors, mechanical Chemoreceptors Chemical, order, taste, body fluid, calcium balance, electrolyte balance Mechanoreceptors Vibration, touch, pressure, stretch, tension Ears, hearing, balance, joints Origin of stimulus (stimulation starts) Exteroceptors – outside of body Interreceptor – inside of body Proprioceptors – sensing of position of movement of body parts Distibution General (somatosensory) senses Touch, pressure, stretch, heat/cold, pain Special senses Vision, hearing, taste, smell, equilibrium Innervated by cranial nerves Types of receptors Uncapsulated nerve ending Dendrites with no connective tissue (not myelinated) or free nerve endings Pain, hot/cold Merkel disc – tonic – light touch Hair receptors – around hair follicles Encapsulated Nerve Endings wrapped in connective tissue (myelinated), most are mechanoreceptors. Meissner capsules (phasic) End bulb – like tactile capsules Bulbous corpuscles Heavy continuous touch, pressure, joint movements Lamellar corpuscles Phasic type of receptors Sense deep pressure, vibration Muscle spindles Found in skeletal muscles Proprioception Tendon organ receptors Somatosensory Projection Pathways Information from a receptor Cerebral cortex Most travel by 3 neurons Dorsal columnar Medial lemniscus pathways Goes up spinal cord Desiccates at medulla oblongata Goes to thalamus out to brain Pain Unpleasant perception of actual or perceived/potential tissue damage Functions So, you avoid or to escape danger Types Nociceptive Comes from injury. Cuts, burns, bone breaking. Detected by nociceptors. It occurs in the skin, mucus membrane, and inflammation. Visceral pain – pain of internal cavities Harder to locate Caused by stretch (full bladder) Deep somatic pain Joints, bones, muscles Arthritis, break, sprain Superficial somatic pain Skin Cuts, burns, etc. Neuropathic pain Injuries caused by nerve damage, spinal cord damage, meninges, brain Feels like stabbing, burning Headache, phantom pain, cancer pain (tumors/chemo) Nerve fibers associated with pain Fast nerve pain Immediate and sharp Myelinated – A delta fiber Can tell where it is coming from – decisive pain Slow pain Unmyelinated Type C fibers Delayed, burning, dull ache Longer lasting Harder to locate the pain Sometimes you can have both Walking you stub toe, immediate pain, but pain continues. Not everyone experiences pain the same 2/1/2024 Pathways of pain Pain from head Travels to brainstem by cranial nerves They will be trigeminal Cranial VI Facial nerve VII Glossopharyngeal IX Vagas X 1st order: takes to medulla 2nd order: medulla takes signal to thalamus 3rd order: thalamus to cerebral cortex – once here we are now conscious of the pain Pain from neck and below Goes to brain step by 1 of 3 spinal cord tracks Spinothalamic tract Carries most somatic type of pain to cerebral Somatic pain – pain from bones, muscles, joints Spinoreticular tract Goes to reticular formation in brainstem To hypothalamus and limbic system Limbic system is our emotional response – crying, behavioral, intense pain we puke This is visceral – pain in guts Gracile fasciculus Sends to thalamus Also, for visceral pain Referred pain Pain in viscera that seems to be coming from somewhere else Cause – nerve signals intertwine, and some signals cannot determine the correct area. Jaw/shoulder hurts but I am actually having a heart attack. Modulation pain Subjective, highly variable, influenced by physical and emotional states Analgesic mechanism – endogenous opioids Enkephalin, Endorphins, Dynorphins Act to block pain Senses Gustation – sense of taste 4,000 – 10,000 taste buds. Taste buds are sensory cells. They detect chemicals called tastents. (chemoreceptors) Bumps on tongue are papillae where taste buds live Taste hairs, cells, taste buds are associated with cranial nerve. Five Primary Tastes Taste communicates by gap junction. Secrete hormones to start digestion Foods coming! Wake up! Neural pathway for facial, Glossophyngeal, and Vagas for taste 1st order – synapse with solitary nucleus of medulla 2nd order – take it to two different areas Nucleus of hypothalamus and amygdala This can activate salivation, gagging, vomiting, memories or emotions Or to the thalamus 3rd order – thalamus to cerebral cortex In cortex there is the gustatory cortex within insula (perception of taste) Can send to frontal cortex Things that can affect taste Color Temp Texture Smell Sense of smell (olfactory) Human behavior can be affected by smells (does it smell like shit or gas? Don't want to be in there for too long) We have constant communication due to smell – pheromones Smells can pull memories Decrease in smell could be a sign of Alzheimer Taste of food change from smell or missing teeth Depression can increase from decrease in scent Responding to air borne chemicals (odorant) are dissolved in mucus membrane 10 – 20 million olfactory cells – bind to chemical to send signals Neuropathway for smell 1st order – olfactory cell pass through the nose and1st order – olfactory cells pass through the nose and enter the olfactory bulb. They synapse with dendrites of mitral or tufted cells. 2nd order – olfactory tract to primary olfactory cortex 3rd – olfactory cortex can then go to some go to amygdala, hippocampus and inside hypothalamus Can make you cough, salivate, vomit Hearing and sound Responsible to vibrating air molecules (mechanoreceptors) Equilibrium – sense of your orientation Movement, balance Inner ear Sound – vibration air molecules that can be transmitted through water, air, semi-solids Air molecules colliding make the eardrum fuel vibration Pitch – treble or bass of something (high or low) Pitch determined by frequency – hot fast or slow – movement of vibration – back and forward (1 cycle) Measured in hertz = Hz (cycles/sec Kids can hear 20-20,000Hz Normal adults hearing – 1500-5000Hz Loudness – perception of the sound. Intensity or amplitude of vibration Measured by dB Normal conversation 60dB Threshold before pain is 120-140dB Prolonged exposure to 90dB can causing hearing loss Anatomy of ear Outer ear – called pineal or auricle Acts to funnel sound into inner ear Long horn for deaf people in old times Auditory canal – external acoustic meatus It is the passageway through temporal bone to ear drum Ear drum – protected by guard hairs and cerumen *earwax* Ear wax coats guard hairs. It also has lysozyme that keeps bacterial growth down and keeps tympanic membrane pliable. Middle ear (tympanic cavity) - is the tympanic membrane or ear drum itself. Separates middle and out ear. Auditory tube (eustachian tube) - passageway to nasopharynx This drains and aerates the inner ear Babies' tubes are not draining properly, or all the way causes ear infections Auditory ossicles (malleolus) - long handle that attaches the tympanic membrane to the incus Incus – articulates with malleolus and states (annuli) Stapes – stirrup shaped (base-foot plate) held in opening to inner ear called oval window Two muscles – stapedius muscle, tympani muscle it is a reflex that protect the inner ear from loud noises Loud bang and we turn – reflex Cerumen – ear wax – used for protection Auditory canal – Facial CNIIV Tympanic membrane – CN IV Glossopharyngeal, X Vagas Inner middle ear Tensor Temperos – CN IIV Stapedius muscle CN IIV – slows down the strength of wave sound Pharyngotympanic l (Estuation tube) - important for draining and equalizing pressure, Atmosphere and inner ear. Occucules Malleas Incus Steppes – taps on oval window When we hear - soundwaves go through earhole to auditory canal. Hits tympanic membrane that vibrates the muscles into oval window (semi liquid) Makes graded potential – changning the charge Hits cochlear nerve CNVIII Never takes impulse to brain Brain to cortex Cochlear Scala vestibule Cochlear duct (scala media) - endolymph Scala tympanic Bony labyrinth – perilymph Ca2+ rich calcium Membranous labyrinth – endolymph – K+ rich potassium Oval window Round window Semicircular canals Posterior - anterior – lateral Bony labrynth – perilymph Vestibule – utricle – saccule Macula – hair cells again – with vizula is the static equilibrium – linear acceleration Cristae ampullary – hairs that maintain posture “angular acceleration” - spinning in circles Auditory pathway 1st order Neuron fibers leave cochlea by cochlear nerve to vestibular nerve. Together they are vestibular coclear nerve CNIIIV – 8. It synapes with second order 2nd order Cochlear nucleus (ganglion) to synapse with 3rd 3rd Inferior caniculi 4th Thalamus Takes to primary auditory cortex Auditory hits back of throat Middle ear infection Cilia, white blood cells to catch microorganism Tempanic membrane can become infected Can rupture Internal jugular (close to middle ear) If infected can go into blood stream Facial nerve IIV if infected (posterior wall) of middle ear Facial palsy – face freeze Close to roof (infection) of brain Meningitis – affects manengi Eye anatomy Tunics Fibrous Sclera Cornea – noireceptors – no blood supply, covers iris Vascular Choroid – helps prevent light scatter (anti blurry) Pigment layer, melanin Iris – dilates and contracts pupil Photo pupillary reflex is an automatic reflex that constricts light. Dilation – SNS Contraction – PNS Ciliary body – ligaments attach lens – it has epithelial cells to create aqueous humor. Ciliary muscle – Changes the shape of lens Tight or loose Ciliary process – produces aqueous humor Pupil – hole that is controlled by iris Sensory Retina – pigment Layers Neuro layer – Photoreceptor cells – rods and cons Bipolar cells Ganglion cells pigmented layer Epithelium cells Rods – scotopic – highly sensitive to light, decrease visual acuity (edges, dark grey, dim light, cannot work in bright light) 11-cis retina + opsin – found in vitamin A Cones – phototropic – low sensitivity to light, increased visual acuity. (cannot work in dark only bright light) Photopsin I, II, III – absorb different wave lengths Red, blue, green Transduction works the same for rods and cones Photoreceptor pigments – proteins are different in rods and cones. Vitreous humor Aqueous humor – constantly made, constantly discharging. It drains into Canal of Schemm or Scalar venous sinus. If it cannot drain, the eye is put under pressure. It will damage the optic nerve = glycoma. This can affect nerve II Eye lid = papelba When you cry the sac drains into nasal lacrimal duct Blood + O2 supply from choroid Epithelium cells – full of melanin 1st order Neuron Bipolar cells 2nd order Ganglion cells 3rd order Lateral geniculate nucleus Signal is sent to visual cortex in occipital lobe Further explained Rhodopsin hit with light 11 cis retinal + opsin Changes to all trans + opsin Opsin hits transducin PDE breaks down CGMP Into GMP And closes the channels Channels closed. Less positive No calcium + sodium into cells Very little GLUTIMATE or neurotransmitters released Little glutamate stimulates the bi-polar cells The bipolar cells send receptor potential to ganglion Ganglion cells stimulated Send action potential to optic nerve Sends visual cortex in occipital lobe Trans retinal has to be regenerated - dark to light – about 5 minutes Cis retinal takes longer - light to dark takes about 20 minutes. Disorders and disease Nyctalopia – night blindness Decrease in photopigments can cause blindness. Developing countries have a lot of child blindness due to lack of Vitamin A Cataracts – cloudness of lens Proteins in lens start to break down Proteins clump together in lens Glycoma – Pressure in the eye Canal of Schlemm plugged, causing pressure Macula degeneration – cells of macula die Causes blindness Lose center of vision first – can see peripheral Hereditary Diabetic neuropathy – blindness by diabetes (uncontrolled) Retinal degeneration Number one cause of blindness of adults Endocrine system Hormones and Neurotransmitters used for communication Exocrine – secretes out through the skin Endocrine – glands are different in that they are ductless They secrete directly into bloodstream It will change metabolism to keep the body in homeostasis Some glands are not classified into endo or exo Liver bile into glands Compare Nervous Sends impulses Specific target areas – nerves on ears React quickly Stop when stimulus ends Fast – for short time Endocrine Sends out hormones General widespread and common Slower reaction Can last for days Slow – effects last longer Chemicals Act as both neurotransmitter and hormones Ex – dopamine – acts as either or sometimes Some neurotransmitters have the same effect on same target Glucagon and norepinephrine on liver Sometimes each system can regulate the other one Neurons trigger the release of hormones Stimuli Neural - signal sent – they tell target to release hormone Hormonal – hormones Humoral – tells difference in blood composition If blood calcium too high or low – will trigger release of hormone Note cards Brain hypothalamus control center Regulate primitive functions = water balance, thermoregulations, effect on hunger, sex drive How – work in conjunction with pituitary gland. Many functions carried out by pituitary gland Pineal gland – center of brain – makes melatonin Makes up sleep Effects the circadian rhythm Seat of the soul – the third eye – old terms Pituitary gland Referred to as “master gland” Hypothalamus Makes and secretes 6 hormones TRH – Thyrotropin – releasing hormone CRH – corticotropin – Releasing hormone GH – Growth hormone PRH – Prolactin – releasing hormone GnRH – Gonadotropin – Releasing hormone Somatostatin – inhibits growth hormone Dopamine – inhibit prolactin Releasing hormones – tells you it is going somewhere else to release hormone Tropin – suffix telling you it is going to another tissue or organ and stimulating it to release hormone Pituitary gland Hypothalamic hypophyseal portal system Hypothalamus makes 2 hormones ADH – Antidiuretic Hormone Oxytocin Both stored in posterior pituitary Anterior Pituitary THS – stimulate thyroid for hormone ACTH – stimulate adrenal cortex for glucocorticoids GH – stimulate mitosis and cell differentiation Prolactin – stimulate production of milk Gonadotropin LH – Luteinizing hormone FSH – Follicle stimulating hormone Anterior pituitary gland is primarily regulated by hypothalamus Involves negative feedback loop - “turns on and off” Higher brain centers Another baby cries and milk is let down (not one’s own baby) Posterior pituitary – primary controlled by neuroendocrine reflexes ADH – released when body needs to retain water Oxytocin Functions Involved in sexual arousal and orgasms Involved in emotional bonding between partners Childbirth – mother child bonding Bonding through milk ejection Function down Hypothalamus – secretes “TRH” Stimulates anterior pituitary to secrete “THS” Stimulates thyroid to release “TH” Thyroid hormone stimulates increase of metabolism of most cells in body Will inhibit release of TSH and TRH from being secreted will stop “TH” from being secreted (Negative feedback loop) Growth Hormone – have wide spread effects Across multiple areas of body. Not 1 or 2 cells, targets, or organs. Ex. Stimulate tissues: cartilage, bone, muscle and fat. Also will stimulate liver to produce insulin-like growth factors Called: insulin-like growth factor IGF-1 and IGF-2 called somatomedins These will target certain cells Growth hormone – short lived, IGF – last 20 hours Will effect on protein synthesis will Is all about tissue growth Lipid metabolism Breaks down fats into fatty acids Used for energy Protein-sparing purpose Carbohydrate metabolism Fatty acids are being used for energy Cells don’t have as great a need for glucose This frees up glucose to be used by the brain Electrolyte balance Glucose can also be used by liver Can have effects on electrolyte balance Promoting Na, K+, Cl- to be retained in the kidneys, boosts Ca+ Will be available for growing tissue GH secretion difference in amount of GH released by activity level and age GH released during first 2 hours of sleep Will peak while exercising Also activated by hormone called “Ghrelin” Released by stomach Increased hunger Stimulates GHRH-7 spike in GH Results in growth spurt Thyroid Gland Follicular cells – secrete TH TH = T3 80% - triiodothyronine T4 20% – Thyroxine What does it do? Increases metabolic rate Greater O2 consumption – heat production Appetite increase GH secretion Respiratory rate can increase along with strength and rate of heartbeat 2. parafollicular cells – secrete calcitonin Decrease amount of calcium in blood stream Endocrine Parathyroid People generally have 4 of them Secretes parathyroid hormone Low blood calcium level is when it secretes/activates It tries to increase calcium levels by: Promote synthesis of calcitriol Increase calcium absorption Decrease the secretion of calcium in urine Increase bone resorption Bone is breaking down and putting calcium in blood Thymus Involved in three systems – huge in infants decreases with age 1st endocrine 2nd lymphatic system 3rd immune system – most important for buidling immune system Secretes thymopoietin, thymosin, thymulin t-cells – site for maturation Adrenal glands Two in one Hormones – medulla – releases catecholamines (epinephrine, norepinephrine, dopamine) Not a neurotransmitter – responses to stress, fear, pain Cortex – secretes corticosteroids Steroid hormones made from cholesterol Mineral corticoids – regulates electrolyte balance Aldosterone ***** released in decreased BP Known as RAA system (Renin-angiotensin-aldosterone system) Bp lowers which activates sympathetic reflex Production of angiotensin Stimulates the kidneys to retain sodium (Na+) Also going to retain water. “water likes to follow salt” Increase and maintain BP and blood volume Glucorticoids – regulate metabolism of glucose Secrete cortisol – secreted in response to ACTH that is secreted by pituitary Cortisol is actually stimulating break down of fats and proteins to release glucose into blood Sex steroids – androgens Responsible for secondary sex characterizes of both sexes Not very active until puberty Pancreas – exocrine (mainly) and endocrine functions Endocrine cells are pancreatic islets “islets of Langrohans” alpha- secreting glucagon between meals, blood glucose levels decrease Beta-secrete insulin-during and after meal - glucose increases Delta- somatostatin cells - Inhibits the release of pancreatic hormones (negative feedback) Also releases Amylin- reduces glucose spikes- slows stomach emptying inhibits glucagon secretion, and signals satiety (Fullness) Brain, kidney, liver and red blood source Gonads-ovaries and testies Both Exocrine and endocrine Exocrine- eggs and sperm Endocrine-gonad hormones and steroids mostly LH- Luteinizing hormones FSH - Follicle stimulating women LH stimulates progesterone-ovulation FSH - Stimulates Follicle = Both together used for Uterine prep Men LH- Lydia cells-testosterone FSH- Sertoli cells Both are used to produce sperm Endocrine with secondary Functions liver-produces five different hormones Calcidol- Helps regulate calcium (ca+) and phosphorous Angiotensinogen - Help regulate BP Erythropoietin-15% - red blood cell production Insulin growth-1 Hepcidin- regulates iron levels Kidney- produces three hormones Function 1. converts calciol to calcitriol - Increases absorption of calcium in small intestine - Inhibits loss in urine 2. Renin-constricts blood vessels to increase blood pressure 3. Erythropoietin - 85% created here red blood cell production. -forces bone marrow to send out blood cells 3. Heart - 1 hormone a. Natriuretic peptides in response to increase blood pressure oppose action of angiotension - kidneys will increase sodium and water output in urine - Drops blood volume-that decrease blood pressure stomach and intestines - secrete alot of hormones to coordinate digestion, appetite control, satiety (Fullness) Chemistry of hormones Steroids made of cholesterol lipid solvables Ammoina peptides amino acids chains of aminoacids They are - water solvable water solvable- cannot penetrate some cell membranes must send second messenger within the target cell "go to" receptor outside of cell membrane to allow to get in. Lipid soluble - can penetrate cell membrane receptor inside of cytoplasm, nucleus Diabetes The hyposecretion or inaction of insulin (not making enough) or insulin isnt absorbing. Classic signs 1. Polyuria - excessive urination z. Polydipsia- excessive thirst 3. Polyphagia- excessive hunger Symptoms 1. Hyper calciumia 2. Increase in blood glucose 3. Glucose in urine 4. Ketones Tupe l- affects children, born with it. individual makes immune cells that destroy the pancreatic cells. They are insulin dependant (pumps, glucose meter) Type 2- develop over time- insulin resistant Treatment: weight control and diet next oral meds if first doesn't work. insulin injection -last resort Uncontrolled diabetes Neuropathy Ketoacidosis-pH level in blood-diabetic coma seizures- loss of potassium and calcium Blind