Integumentary System Functions PDF

Integumentary System. Functions of Integument · protection : from injury , harmful substances , extreme temps , J radiation prevent water loss/gain : Epidermis water resist...

Integumentary System. Functions of Integument · protection : from injury , harmful substances , extreme temps , J radiation prevent water loss/gain : Epidermis water resistant not waterproof · is · water loss by sweat & transpiration · Metabolic regulation : Formation of Vit D ; a precursor to calcitrol 4) calcitrol increase of calcium absorption phosphate ↳) from diet blood levels ; regulates Calc. · Secretion & Absorption : Waste productions secreted onto skin surface while sweating · skin absorbs some chemicals/drugs but blocks others. selectively · permeable Suitable for transdermal administration of some drugs ImmuneFunction : Dendritic cells in epidermist dermis are capable of initiating immune response Temperature Regulation : Dermal blood vessels Capable of vasoconstriction to conserve heat or vasodilation to release heat Sensory Reception : Extensive innervation allows for detection of stimuli  Epideronis · feratinized , stratified squamous epithelium · layers (Strata) From deep to superficial. Stratum Basale 3 1. 2 Stratum Spinosum composed of living Karatinocytes 3 Stratum. granulosum 4 Lucidum thick. Stratuo > - only in skin.. 5 Stratum Corneum. ~ Palms + soles have all S layers Arm head , etc Lucidum layer leg not have · , will * what layers do needle through when puncturing to the dermis ? * a go · 4 layers ↳ basale spinosum , , granulosum , corneum. Xepidermis always replacing itself. Grow from base layer Stratum Basale : Deepest Epidermal Layer single layer of cuboidal to low Columnar cells - three cell types : Keratinocytes , Melanocytes, Tactile Cells Keratinocytes : Found basale · in all layers but in they are large stem cells ; Divide to regen new cells Synthesize Keratin ; protein that strengthens Epiderms · Melanocytes : pigment producing + protest from UV · Stratum Spinosam : Composed of several layers of cells With centrally located nucleif spinelike processes , large , oval · limited mitosis several layers of polygonal Keratinocytes Daughter from basale layer pushed into this layer - cells Non-dividing Keratinocytes attached by intercellular junctions · desmosomes · Epidermal dendritic cells - found in stratum Spinosum & Clangerhans cell) granulosum ↳ initiate immune Response more oblong shaped · Stratum Granulosum : Cells have granular appearance + are flat , & spindle shaped · as cells die theyre filled to granules of Keratin , ↓ Keratosination Chardening of cells) takes place ↳7 makes waterproof 3-5 layers of Keratinocytes · nucleus & organelles disintegrate · ↳ ells dead. Stratum Lucidum : only found in thick Skin narrow transparent layer (clearlayer) 2-3 layers thick densely packed flat cells filleda Keratin · , , · cells filled w translucent protein called eleidin Stratus Corneum : Superficial stratum composed of 20-30 layers of dead interlocking , , Keratinized Cells Dry thickend surface protect against abrasion & infection · , · nuclei dead & dissolved (cell dead)  Dermis & Deep to epidermis · composed of CT 2) other structures blood present : vessels , sweat glands , sebaceous glands , hair follicles nail roofs endings , arrector pili , , Sensory nerve Papillary& reticular layers Collagent elastic fibers oriented parallel bundles specific locations · in at Bundles function to resist stress during routine movement · · Orientation indicated by lines of clearage (tension Lines) parallel to lines more likely to heal incisions cleavage quickly · ↳↓ Vice versa if skin stretched beyond Some collagen fibers · capabilities are torn Stretch ↓ marks (striae) Functions : Temp Regulation dialating : blood vessels release heat constricting conserve heat · sweat glands release fluid on to surface of skind body cools evaporation secretion & absorption : Sweat glands release sodium , water Curea toSurfa · ↓ sebaceous glands secrete subum sensory Reception : Variety · of sensory receptor structures  Subcutaneous Layer · hypodermis , superficial fascia not part of integument · Areolar & adipose CT · Functions : Protection , energy storage , O insulation common site drug injection · ↳ extensive Vascular network promotes rapid absorption. Why do patientsw full thickness burn feel no pain at 1st ? · First degree : only epidermis full thickness burn all rednessa pain slight the to · down way burned hypodermis immerse · area in cool water Ind degree : epidermis + part of Dermis ↳ nerve burnt. · endings · skin blister & painful slight scarring · · zrd degree: Epidermis , Dermis , + subcutaneous layer hospitalization · Treatment for dehydration + infection · Require additional caloric intake severe scarring · debridement ↓ skin graft · · loose ability to retain water Fight pathogens · Burn severity can be measured by rule of nines ↳ estimate surface area of burns What can happen if skin is broken exposing internal envir.? Glandular , nervous , a Vascular Locations : Glands , nerves , t blood vessels located in dermis · Glands secrete · sensory nerves · blood vessels Idialate t constrict for temp) · hair folides , Keratin & Melanocytes Keratin keeps Skin waterproof ~ - Melanocytes Protect Skin from Or · - ↳ contribute to skin colour Vitamin D & Calcium. · absorbing Vitamin D helps body absorb calcium.  Nervous system Functions of NervousSystem · monitors internal + external environments process integrates sensory information Sk muscle 1SNS. T · electrical commo Signaling electrical throughout body xx- Eff- > Autonomic NS > PNS - works wendocrine · system S[ volunt involuntary · Visceral sensory responses ↑ (Autonomic NSL (internal organs) Somatic Sensory crest of body) General Functions & Organization of NS Central Ns (CNS) - Brain & Spinal Lord Peripheral NS(PNS) - Nerves & Ganglia ↳ like extension cords that plugin to spinal co Functions : · collect info : Receptors detectStimuli I send Sensory Signals to spina cord. · process & evaluate info : Brain o Spinal Lord determine response to sensory input response to info Brain Uspinal · Initiate : cordSend motor output via nerves to effectors.  * Pict question Neuron Structure. on test Post-synapic , or receving end andrite Y Pre-synaptic or 3 , Nucleus contain - Ach I - axon Hillock I cell Body1 myelin sheath of transmission Direction Transmit nerve (yellow) impulse to axon ↳ make speed of term. transmission fast ↳ make dec. If axon will fire cell body: (Soma · Plasma membrane encloses Cytoplasm (perikaryon contains nucleus initiates Some graded potentials , receives others from dendrites & conducts these potentials to axons Contains chromatophilis substance made of ribosomes Dendrite : unmeycinated process branching off cell body receive inputI tranfer to cell body Axon Hillock : Transmit nerve impulse to axon terminal ↳ make dec , if axon will fire Axon dominal : contains Ach neurotransmitter. Myelin Sheath : make transmission fast Schwann Cell : maintenancea regeneration of axons of theneurons in PNS Nodes of Ranvier : repeaters regen the action potential as it moves , along the axon (e g Saltifory.. Conduction).  ligh Gans / Posterior Di va ! S. inpu mitee & - & output - M --Anterior. What * iroamixedoute. Spinal & Cranial Nerves · Structural Classification of nerves : Cranial Nerves : Extend from brain Spinal Nerves : Extend from Spinal Cord · Functional Classification of nerves : Sensory Nerves : Contain Sensory neurons Sending Signals to CNS Motor Nerves : contain motor neurons Sending from CNS Signals Mixed Nerve : Contain sensory t motor neurons most named nerves are in this category · · individual axons in these nerves trasmit only1 type of info  Nerves & Ganglia Nerve: Bundle of parallel axons in PNs Nerves have 3 connective tissue : wrappings. · · Epineurium : encloses entire nerve ↳ thick layer of dense irregular CT · Perineurium : Wraps Fascicle (bundle of axons in nerve ↳ layer of dense irregular (T · Endoneurium: wraps individual axon separates & each axon electrically insulates · ↳ Delicate layer of areolar CT · Nerves are vascularized ↳ blood vessels branch through epineurium a perineurium to become capillaries ; allows for exchange between axon t blood. ↑ Epi -Peri - Endo Ganglia : Cluster of neuron cell bodies within the PNS cluster results in swelling , or enlarged portion along length · , of a nerve · 2 types : posterior (dorsal root) ganglia associated w sensory neurons that extend into Spinal cord( that ganglia associated motor neurons · w extend to autonomic effectors for Parasympathetic & Sympathetic Divisions  Neurons at Rest Characteristics of resting neurons : · higher conce of ht in eytosol verses interstitial fluid (IF) of Nat Cl- · higher conc. , , cat in If than in cytosol ~ gated channels are closed · cytosol is relatively negative compared to IF RESTING MEMBRANE POTENTIAL IS -TOmU - All through nerve cells Resting Membrane potential (RMP) kt diffusion important factor RMP most setting · is in gradient K + Cone. · diffuses out of cell due to its · ifKt were only on that leaked , RMP would be where K + cone. electrical gradients are at equilibrium (-90mV Since there are few Nat leak channels , Nat also influences RMP ↳Nat diffuseinduetoitsCongradientelectricalgradienta EpsPUfire wants to make close to -ssmV to catat Fire IPSPX don't Fire will want to make volta a genele - 70-80 mV +o ↑ not fire EPSP = Excitatory post synaptic potentials I IPSP = Inhibitory post - TomU - 55mV tells axon to depolarize d fire synaptic potentials axon aXon Axon Hillo X terminal · ↳ Accountant cell body & dendrites  * Glial Cells. name , location , f CNS Function Glial Cells : non-excitable , Support Cells found in CNs & PNs smaller ; half volume of NS , but outnumber neurons I mitosis · a nourish protect neurons · provide physical scaffolding for nervous tissue ↳ guide migrating neurons during development · critical for normal function at neural synapses Glial Cells of CNs. Astrocytes - most abundant glial cells in CNS 1 help · form blood-brain barrier ↳ wrap feet around brain capillaries ↳ controls what substances have access to brain 2 regulate tissue fluid composition (chemical environment around neurons) ↳ Conc. regulate ex : can potassium. Provide structural support f organization 3 to CNS 4) Assist Neuronal development S - occupy space of dying neurons Ependymal Cells : line cavities of brain & Spinal cord part of choroid plexus , which produces cerebrospinal · fluid &. circulates it Microglia : small cells that wander CNs & replicate in infection · phagocytic cells of immune system engulf infectious agents & remove debris Oligodendrocytes : large cells w slender extensions around axons of extensions wrap neurons forming · myelin Sheath (faster) · in Central US  Glial Cells of PNS Satellite cells : Electrically insulates PNS cell bodies · regulates nutrienta waste exchange for cell bodies in ganglia Neurocemmocytes (Schwann cells) : Myelinates ( insulates PNS axons ~ allows for faster action potential For propagation axon. along Action Potential : Events Action Potential Steps in depolarization: 1. At RMP , voltage gated channels are closed 2 As Nat enter from. adjacent region Voltage gated , Nat channels open. 3 Nat enters the axon causing membrane to have positive potential 4. Nat channels close becoming inactive (unable to open) temporarily Steps 1.4 repeat in adjacent regions & the impulse moves toward synaptic knob Action Potential steps in repolarization 5 depolarization slowly opens It channels , 2 It diffuses out , causing. negative membrane potential K + channels open for makes 6 : longe time soIt exit cell more negative than RMP (hyperpolarization ( Nat rushing in ATO Lisation cel ATP It in voltage) SSMV I slowly are polar v Tom gate - - ATP AR ⑭ Nat/k + pump will ⑭ equalite (- Tom V)  Events of an Action Potential 1 The unstimulated has. axon a resting membrane potential of - Tom 2. Graded potentials reach the initial I are added together Segment (-70mV-t- 55mV. Depolarization 3 occurs when threshold L-56mi) is reached ; Voltage gated Nat channels open ↓ Nat enters rapidly the to reversing polarity from negative positive (-55mV - + 30mv) 4) Repolarization occurs due to closure of oltage gated Nat Channels (inactivation State ↓ opening of Voltage gated channels It It. moves out of the cell & polarity is reversed from positive to negative ( + yomut -Tomr) 5. hyperpolarization occurs when Voltage gatedIt channels Stay open longer than the time needed to reach RMP this. During time the membrane potential is less than the RMP Gomv--8OMU) 6. Voltage gatedIt channels closed the plasma membrane has returned to resting conditions by Nat/k + pumps (-somut-omv)  Continuous US. Saltatory Conduction Continuous Conduction : occurs on unmyelinated axons charge opens voltage-gated channels which allows · , charge to enter which spreads to adjacent region & , opens more channels Sequentially Saltatory Conduction : Occurs on myelinated axons · Action potential occurs only at neurofibril nodes , which is where the axon's voltage gated channels are concentrated · After Natenters at mode it starts a a rapid positive current down the inside of the axons myelinated region · the current becomes weaker w distance , but still strong at next node. enough to open Voltage gated channels ~ full action potential occurs at mode , J process repeats impulse jumping from node to node much faster than continuous & myelinated · use less ATP cells to maintain resting membrane potential Continuous conduction slower 11(((((1161666 Axon salitory conduction, i Faster MOTOTN not P Axon · touchand of ranvier insta Myelin - nodes thingck  Classification of Neurotransmitters # can classify by chem , function , faction · 4 main chemical classes of Neurotransmitters Acetycholine : Differs substantially from other transmitters Biogenic Amines : An amino acid is slightly modified to synthesize the transmitters ↳ catecholamines (ex: dopamine) are made from tyrosine 4) Indolamines (ex: Seratonin) are made from histidine or tryptophan Amino Acids : Include common transmitters glutamate, glycine , GABA Neuropeptides : chains of amino acids (2-40 long) including endorphines Neurotransmitters can also be classified by function ↳ effect on membrane potential · Excitatorytransmitters cause EPSPS inhibitory transmitters cause IPSPs classification by action : Direct transmitters-bind that to receptors are chemically gated channels (immediate postsynaptic potential) second messengers ndirect-bind to receptors that involve G-proteins & more diverse effects possible· Acetylcholine : · use in PNS to stimulate skeletal muscles (NM)) ~ used in CNS to increase arousal t alertness · synthesized from acetate t choline · stored in synaptic vesicles · Action potential triggers its release in to cleft some ACh attaches briefly to postsynaptic receptor · Ach · is cleared from cleft by being broken down by Acetylcholinesterase by presynaptic · Acetate t choline are taken up cell recycling for · Effect on target cell depends on receptors present ↳ Nicotine - always excitor for next cell in line ↳ muscarinic - could be excitable or could inhibit