Path of Light In Eye

• cornea, fluid filled anterior chamber, lens, vitreous body, retina

External Tunic: Sclera

• opaque and tough dense fibrous connective tissue
• partly visible on the outside of the white eye
• relatively avascular
• continuous with cornea

Middle Tunic: Choroid

• vascular layer 
• heavily pigmented(dark)
• continuous with uveal tract

Internal Tunic: Retina

• 10 cell layers: light receptors, processing neurons, accessory cells
• more on other cards
• most complicated
• light sensitive part on choroid side not vitreous side

Hair Cells

• bace unit that recieves stimuli for sound and balance
• stereocilia and kinocilia(1 large)(hairs) project into endolymph and waves in it bend hair cells opeing up ion channels
• allows for k+ and Ca++ to enter, stimulating neuron
• carried down CN VIII

Pigment Epithelium

• layer of retina closest to choroid
• rods and cones the next layer
• absorbs light after stimulation of rods and cones
• regulate growth and turnover of rods and cones and play a role in regeneration of rhodopsin(visual pigment in the rods)

External Plexiform Layer

• region of synapse btween rod and cone cells and bipolar cells
• area of lateral integration of visual information

Inner Nuclear Layer

• contains nuclei of bipolar cells, muller cells, horizontal cells, and amacrine cells
• transmit and modify (modulate) the signal from the rod and cone cells

All Ten layers of Retina

• pigment epithelium
• rods and cones
• external limiting membrane
• external nuclear layer
• external plexiform layer
• inner nuclear layer
• internal plexiform layer
• ganglion cell layer
• nerve fiber layer
• internal limiting membrane

Photosensitive Region

• membrane discs
• invaginations of the membrane in a rod or cone cell
• holds pigments that are photosensitive
• rod cells have rhodopsin and cone cells lodopsin(3 variations for different wavelengths
• cone cells concetrated in fovea(less sensitive)

Action in Rod Cells

• light hits rhodopsin, bleaching it
• opsin and transducin seperate from it
• opsin leaves cell and transducin goes down and inhibits the uptake of Na+
• leads to decrease release of neurotrnsmitter (normally continuous)

Detached Retina

• normally intraocular presure is only thing holding pigment epithelium against the rest of the eyeball
• decrease in presure leads to a detached retina
• peceives initial rupture as a sudden flash, since the rod and cone cells are abrubtly stimulated
• retina is detached while pigment epithelium stays with choroid
• when detaches that part of visual field is "blind"

Aqueous Humore

• made by cilliary body (processes)
• this humor fills the anterior and posterior chamber of the anterior part of the eye
• humor flows from posterior to anterior chamber
• drains through the Canal of Schlemm that drains into extraocular veins

Glaucoma

• occurs when the aqueous humor does not drain
• often because canal of schlemm is plugged
• intraocular pressure increases because aqueous humor is constantly produced
• eventually optic nerve is damaged resulting in blindness
• treated by suppressing production or surgery to widen the canal of schlemm

Cornea: Histology

• Simple squamous non keratinized cells turn over every 7 days
• next layer is bowmans membrane, thick and supports shape
• avascular stroma consiting of regularly aranged collagen bundles secreted by flat fibroblasts
• descemets membrane and then endothelium(Simple squamous) before ant cham
• continuous with sclera

Iris: Histology

• continuous with choroid
• perforation that can be regulated to let light in
• color caused by amount of melanin per malanocyte in iris
• more melanin leads to darker eyes
• green caused by changes in structure of melanin protein, another SNP
• opening called pupil
• dialator and constrictor pupillae are muscles for iris

Cataracts

• cloudy areas in lens
• develop slowly and cause blind spots
• unprotected sun exposure, trauma, diabetes and aging cause cataracts
• opaque lens can be removed and replaced with artificial

Lens: Histology

• focuses light onto retina by changing shape
• smooth muscle fibers in ciliary body contract to change shape, process of accommodation
• suspended to ciliary body by zonule fibers
• basement membrane forms a capsule for lens
• subcapsular epithelial cells produce lens fibers filled with protein called crystallin

Ciliary Process

• extend from the ciliary body and anchor the zonule fibers
• inner pigmented epithelium
• outer non-pigmented epithelium that secretes aqueous humor

Ora Serrata

• circular edge of photosensitive part of the ritina
• light that falls in at a high angle does not stimulate the photoreceptors above this point
• retina anterior to ora serrata consists of just two layers

Fovea and Optic Disc

• fovea is area with high density of cones but no rod cells(high acuity low low-light performance)
• optic disc is where the optic nerve runs from and is not photosensitive 

Tunics of the Eye

• sclera(external)
• choroid(middle)
• retina(internal)

External Limiting Membrane

• btw photoreceptors and muller cells
• muller cells support retina

Endolymphatic duct

and 

Endolymphatic Sac

• extends from the vestibule to the subdural space(btw dura and arachnoid inside cranial cavity) where it ends blindly (endolymphatic sac
• filled with endolymph and the duct is the site where immune cells can cross into the endolymph
• endolymph is made in the stria vascularis

Perilymphatic Duct

• extends between vestibule (of inner ear) to subarachnoid space
• perilymph is derived from cerebrospinal fluid

Cochlea

• hearing
• bony structure
• different hair cells stim based on frequency of sound
• peri and endolymph
• organ of corti
• CN VIII

Saccule

• linear acceleration
• endolymph (bathed in perilymph)
• macula of saccule
• inside gelatonous layer (macula) are otoliths(calcium carbonate) that gives the mass more inertia, causing slight delay to body movements causing hairs to move)
• CN VIII

Utricle

• linear acceleration
• endolymph (bathed in perilymph)
• macula of utricle
• inside gelatonous layer (macula) are otoliths(calcium carbonate) that gives the mass more inertia, causing slight delay to body movements causing hairs to move)
• CN VIII

Semicircular Canals (3)

• arranged in 3D to pick up angular acceleration
• perilymph and endolymph
• hair cells in ampulla (3 of them)
• hair cells project into cupula(gelatonous mass)
• CN VIII
• canals are part of bony labyrinth and ducts contained with in are part of membranous labyrinth

Structures of Cochlea

• Branch of CN VIII (through axis)
• scala vestibuli (top)
• scala tympani (bottom)
• both filled with perilymph
• scala media (cochlear duct) (endolymph space with hair cells)
• spiral ganglia and spiral organ in btw two scalas
• stria vascularis on abaxial wall of scala media

Tectorial Membrane

• glycoprotein rich gel
• made by spiral limbus
• stereocilia of hair cells in cochlea stick into it

Basilar Membrane

and 

Spiral ligament

• membrane of which cochlear hair cells are implanted on
• ligament on outside of haircells that connect them to stria vascularis

Stimulation of Cochlea

• low frequency sounds stimulate the apex of the cochlea 
• high frequency sounds stimulate the base

Damage to Hair Cells

• certain frequencies damage hair cells for specific part of the spectrum
• overstimulatd hair cells first lose some sensitivty and after multiple or long exposures lead to deafness
• cochlear implants (spiral electrodes) can be tuned to give a patient some frequency perception

Petrous Section

• part of the temporal bone 
• contains all parts of the inner ear
• cavity called bony labyrinth(perilymph) with membranous labyrinth inside containing endolymph.
• hair cells inside

Helicotrema

• vibrations pass through scala vestibula to scala media
• pass through this window to scala tympani
• then goes back to base of cochlea
• round window then dampens vibrations 

MHC

• Major histocompatability complex molecues in immune system (self molecules)
• all nucleated cells in humab body(so not mature RBC's) have MHCI molecules embedded in their plasma membranes that are unique to each person
• only phagocytic WBC's that have engulfed a pathogen(active) display MHCII molecules (neutrophils, monocytes, macrophages, eosinophils and b lymphocytes)
• bound to surface of these MHCII will be fragments from the destroyed microbe(epitopes)

PAMP's/PPR

• Pathogen Associated Molecular Patttern Proteins(non-self immmune)
• repetitive glycoproteins(long) that are associated with bacterial capsul and glycocalyx, viral capsule, ect
• Pathogen recognition receptors on non-specific defense cells recognize these(also called TOLL receptors)
• neutrophils, macrophages, natural killer cells

Cytokines

• special chemical signaling molecules produced by immune cells
• affect other immune responding cells
• multiple types including: pro-inflammatory, complement proteins, interleukins, antibodies, interferon

Proinflammatory

• cytokine
• histamine(basophils and mast cells)
• prostaglandis(relased from damaged cells)
• histamine introduces vasodialtion(inc cell permeability)
• prostaglandins induce smooth muscle cell contraction, opening up spaces between endothelial lining(increases diapedisis)

Complement Proteins

• soluble protiens c1-c9 (cytokines)
• cells of liver-hepatocytes produce these
• these proteins cleaved to active form 
• some of these fragments proinflamatory (c3a and c5a)
• also target bacterial cell wall, parasite surface cells/plasma membrane

Interleukins

• cytokine
• IL1-IL36 promote diferentiation, maturation and/or activation
• produced by white blood cells of immune system(macrophages, t-lymphocytes, b-lymphocytes
• targes WBC's endothelial cells, RBM stem cells
• induces production of new enzyme or rapid mitosis (IL 2, 4, 5, 6)->produces colonal army 

Interferon

• cytokine
• INF-alpha, INF-beta, INF gamma(INF type I and II)
• produced by virally infected cells or cells that have become tumor cells
• no benefit to cell it produces
• difuse to nearby proximally noninfected cells and downregulate nuclear polymerases(halts mitosis and protein synthesis)

Antibody Structure

• 2 heavy chains, each with variable and constant region
• 2 light chain: each with variable and constant regino
• vaiable regions of heavy/light chains= site where antigen epitope binds(unique)
• stem (FC region) and arm region
• FC regin recognized by white bloodcells that have receptors for it (mast cells and basophils degranulate when in contact with this)

IgG

• monomer
• 75%-85% of antibody percentage in plasma
• also present in fetal circulation in pregnant women 
• activates phagocytosis, neutralizes antigens
• only molecules that can cross placenta and second antibody released in process

IgM

• pentamer, 5-10% antibody percentage in plasma
• also present in Blymphocyte surface(as monomer)
• first antibody produced in initial immune response
• activates complement
• has total of ten recognition sites (increases likelyhood of tagging a pathogen)

IgD

• monomer
• 0.001% of antibodies
• also present on surface of B lymphocytes
• antigen receptor triggering initial B cell activation
• both resting and active B lymphocytes produce these
• a surface receptor

IgA

• a dimer with J chain and secretory component
• 10-15% of antibodies
• also found in secretions(milk, saliva, tears)
• protects mucosae

IgE

• monomer
• 0.002% of antibodies
• destroys parasitic worms and participates in allergies
• produced against an allergen
• first produced in bcells then bind to surface of mast cells and basophiles

Anaphylaxis

• Nausea and vomiting, difficulty in breathing, fast circulatory collapse
• systemic vasodialation
• caused by IgE on mast cells 

Neutralization

• antibodies covers biologically active protion of microbe or toxin
• this prevents it from being takin into an unsuspecting cell
• antigen-antibody complex is insoluble, making it easier to be hunted down (precipitation)

Agglutination

• antibody cross-links cells(bacteria), forming a clump
• sets cluster of pathogens at feet of neutrophils/macrophages

Opsonization

• Fc region of antibody binds to receptors of phagocytic cells, trigering phagocytosis

Membrane Attack Complex

(MAC)

• protein complex formed in the last steps of complement activation
• C6, 7, 8, 9
• targets bacterial cell walls and membranes and cell surface/membranes of parasites
• punches hole in membrane, lysing cell 

Perforins, Granzymes

• created by killer tcells(for virally infected cells) and NK cells (for tumor cells)
• perforins punch holes in membranes
• granzymes are degradative enzymes

Complement Activation Pathway

• 6,7,8,9 are MAC
• Mannose binding lectin pathway(day 1)
• classic pathway-antibodies required (day 5-7)
• C1 for classic
• C2,3,4,5 for mannose binding 

Mannose-Binding Lectin Pathway

• starts day 1
• mbl is a protein produced by hepatocytes that recognizes mannose(sugar) in glycocalyx of most bacterial cells
• binds to surface of the bacteria and recruits C4 protein from lymph and blood(inactive)
• cleaved into two smalled active fragments (C4a and c4b)
• C4b recruits C2(activates it). C3 then binds and activates
• C5 then binds and activates (C5a and C3A are autoinflamatory
• MAC then recruited 

Primary Amyloidosis-Immunocyte Dyscrasia-AL

• dyscrasia referes to abnormal component of blood
• amyloidosis: abnormal extracellular deposists (misfolded proteins) that are difficult to degrade and accumulate causing tissue/organ loss of architecture and function
• immunocyte dyscrasia: abnormal b lymphocye proliferation results in excessive production of Ig Light chains. can lead to renal, splenic and lymph node patholgies

Immunocyte Dyscrasia

• excessive Ig Light Chains
• appear greenish in electromicrograph of renal tissue (kidney)

Subcapsular sinus

• second space in a lymph node
• contains dendritcic cells (macrophages) that are also called APC's (antigen presenting cell)
• job of these is to induce a specific adaptive response by displaying antigens to the TH1 or TH2 cells in cortex 
• attached in a network

High Endothelial Venules

(HEV's)

• venule in lymph node
• very pouros 
• about 30% of volume is immediatly moved into the venule
• allows mostly water molecules to move through but not larger pathogenic or toxic molecules
• creates viscous drag in the artery to slow down the blood flow of the pathogens 

4 Types of Tonsils

• pharyngeal tonsils (single mass) (adenoid)
• palatine tonsils (paired)
• lingual tonsils (lumpy bumbs posterior to foramen cecum)
• tubular tonsils (paired)

Primary And Secondary Immune-Lymphatic

Organs

• Primary are red bone marrow, thymus (where immune cells are produced)
• Secondary are tonsils, lymph nodes, spleen (where immune cells mature/activate)

Blood Flow Through Spleen

•  splenic artery to
• trabecular arteries/surrounded by Periarteriole lymph. sheaths
• to central artery/surrounded by WBC Follicle
• to penicillar arterioles and radial  arterioles
• capillary network/surrounded by macrophages
• splenic sinusoids/stave cells
• trabecular veins
• splenic vein

Lymphatic Vessels

• have a capsule and trabeculae
• afferent(in) and efferent(out) vessels and have valves
• reticulocytes make connective tissue for support
• primary nodule has no germinal center and secondary does (can switch back and forth)
• life span of activated b lymphocite is 3 wks and takes 1 week to activate

Sinusoid in Spleen

• surrounded by reticular fibers
• composed of specialized epithelium called stave cells that are long and run in parallel and have openings in them 
• deformed red blood cells can not fit through these openenings after leaving an open system so they no longer enter circulation and are destroyed by macrophages

Thymic Epithelial Cell (TEC) 

• form thin cytoplasmic extensions with adjacent TEC
• six different subcatagories of TECs
• wrap around clusters of lymphoblasts 
•  TECs in cortex produce thymopoetin (thrombopoetin)
• Hassels Corp. (a TEC) produce lymphopoetin (in medulla)
• form blood thymus barrier(to stop self proteins from forming autoimmune disease)

Positive Selection

• happens to tcells in cortex
• only going to positivly move on to the medulla if they can recognize NHC1 and NHC2 Molecules
• in medulla must be able to recognize nonself proteins from self proteins 
• if they recognize self proteins they undergo apoptosis
• lose one of there CD markers (CD4 or CD8)

DiGeorge Syndrome

Peptide/Protein Hormones

• comprised of unique sequence of amino acids
• hydrophilic-easily travel through aqueous solution (blood/ECF)
• induce rapid/immediate changes within target cells
• rapidly degrade (short half life of mins to hours)
• exert their biological effect on target cells via second messenger systems

Steroid Hormones

• comprised of cholesterol precursor
• hydrophobic
• must be transported through aqueous solution bound to a transport protein
• induce changes in target cell nucleus(alter mRNA transcription)
• relatively long half-life (hrs to days)
• transported on albumin or LDL from liver hepatocytes 

Anterior and Posterior Pituitary

• anteior pituitary is the adenohypophysis
• posterior pituitary is the neurohypophysis (contains infundibulum and pars nervosa)

Posterior Pituitary

• neurohypophysis
• pars nervosa releases ADH (supraoptic nucleus) and oxytocin(paraventricular nucleus) 

Component Protein 1

• made up of 1Q-1R-1S
• part of classical pathway 
• binds to FC region of antibody molecules and from here story is same as other pathway
• this is why classical is slower, needs an antibody

Spleen

• has capsule and is the largest lymph organ
• red pulp and white pulp
• white is compact and dark staining with central artery
• red is very vascular and spread out
• filters blood instead of lymph
• has a partially open circulatory system

Peptide/protein Hormones

and

Steroid Hormones

• ultimately phosphorolate an inactive protein to activate it
• can be ion channels or other forms
• steroid hormones bind to HRF region upstream of a DNA promoter and facilitate the making of new proteins

Relationship btw organ location

and product

• hormones produced above neck are peptide/protein
• hormones produced below neck are steroid hormones
• calcitonan and PTH are peptide 
• thyroid hormones are stroids