Anatomy and Physiology 1 Exam Guide PDF

Study Guide for Anatomy and Physiology 1 (Final Exam) For the exam, understand the following concepts and apply them to examples. Note that I can ask a questions relating to anything in my lecture, the points below are the major concepts from each lecture. Please know the terms and definitions in ea...

Study Guide for Anatomy and Physiology 1 (Final Exam) For the exam, understand the following concepts and apply them to examples. Note that I can ask a questions relating to anything in my lecture, the points below are the major concepts from each lecture. Please know the terms and definitions in each lecture. Chapter 1 – Introduction - Definition of anatomy and physiology - Physiology ( function): structure determines function - Anatomy(structure):study of composition and location The levels of organization - Organism level: organ systems work together to maintain homeostasis - Organ system level: group of organs; perform specialized set of functions - Organ level: two or more types of tissue; perform a specific task - Tissue level: groups of cells; perform a function - Cellular level: smallest unit of life; perform specific functions - Chemical level: has atoms and can combine molecules with complex shape Homeostasis o Definition - a stable environment in the body, both chemically and physically o Function of three biological components - Receptor: receives stimulus, monitors, send feedback to control center - Control center: process signal, sends instructions - Effector: carries out instruction What is a Negative feedback loop? - a mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation (opposite of the original change) What is a Positive feedback loop? - feedback that tends to magnify a process or increase its output; the response of the effector increases change of the stimulus Chapter 2 – Biochemistry Subatomic parts of an atom (proton, electron, etc.) - Proton: positive charge - Neutron: neutral  - Electron: negative charge - nucleus, electron cloud Electron shells and how many electrons each wants to hold - Lowest shell: 2 electrons - 2nd shell: 8 electrons - 3rd shell: likes to hold 8 electrons (can hold 18) Definitions of molecules and compounds - Molecule: two or more atoms, joined by strong bonds(H2) - Compound: two or more atoms, different elements (H2O) Ionic bonds, how they work and what sort of atoms tend to produce them - Cation (electron donor): loses one or more electrons, positive charge - Anion (electron acceptor): gains electrons, negative charge - The attraction between the opposite chargers then draws the two ions together - Typical its a metal or nonmetal atom that produces them Covalent bonds, how they work and what sort of atoms tend to produce them - They are electrons shared between atom, one electron is donated by each atom to make the pair of electrons - Single covalent: sharing one pair of electrons - Double covalent: sharing two pair of electrons o Polar vs. nonpolar bonds - Polar: equal sharing of electrons, atoms have equal pull on electrons - Nonpolar: unequal sharing of electrons, one atom has a stronger pull on electrons Hydrogen bonds, how they work and what sort of molecules tend to produce them - Electrical attraction between polar molecules; attraction between slightly positive end and slightly negative end - Gives water a lot of its unique properties: surface tension and floating ice Difference between organic vs inorganic compounds - Organic: molecules constructed around carbon; biologically produced - Ex: carbohydrates, proteins, lipids, and nucleic acids’ - Inorganic: molecules not constructed around carbon; includes some simple carbon based molecules; not solely biologically produced - Ex: carbon dioxide, oxygen, water, and inorganic acids, bases, and acids Hydrophilic vs hydrophobic - Hydrophilic: hydro - water, philos - loving - Interacts with water; includes ions and polar molecules - Hydrophobic: phobos- fear  - Does not interact with water; includes nonpolar molecules, fats, and oils pH and the pH scale - pH: the concentration of hydrogen ions (H+) in a solution - Neutral pH: balance of H+ and OH- - Pure water: 7.0 - pH scale: inverse relationship with H+ concentration - Acidic (pH lower than 7.0): high H+; low OH- - basic(pH higher than 7.0): low H+; high OH- Carbohydrates o Function - Energy - Energy storage - structure Lipids o Fatty acids ▪ Function - Long chains of carbon and hydrogen and energy storage o Phospholipids ▪ Function - structural lipids: components of plasma membrane Proteins o Basic structure (made up of amino acids) - Contains basic elements: carbon, hydrogen, oxygen, and nitrogen - Made from 20 types of amino acids o Functions - Results a molecule as a polypeptide Nucleic Acids o Function - Store and process information at the molecular level o High Energy Compounds - A modified nucleotide that can be used to store and transfer energy ▪ How ATP stores energy - Adding a phosphate group to ADP: creates high energy energy bond Chapter 3 – Cell Biology Plasma membrane o Functions: - Physical isolation; a barrier  - Exchange with the environment; ions and nutrients in; wastes and cellular products out - Sensitive to external environment: detect extracellular fluid composition; receives chemical signals - Structural support; anchors cells and tissues exchange: ions and nutrients in and wastes and cellular products out sensitivity: detects extracellular fluid compositions and receives chemical signals Support: anchors cells and tissues Cytosol Nonmembranous organelles o Cytoskeleton ▪ General function Microfilaments: provide mechanical strength, attach cytoskeleton to cell membrane and pair with thick filaments of myosin for muscle movement Intermediate filaments: strengthen cell and maintain shape, stabilize organelles, and stabilize cell position Microtubules: strengthen cell and anchor organelles and change shape o Microvilli ▪ Function: finger shaped extension of cell membrane, increase surface area for absorption, secretion, and allows attachment to surfaces o Centrioles ▪ Function: form spindle apparatus during cell division, made of microtubules o Cilia ▪ Function: small hairlike extensions, made of microtubules, beat rhythmically, moves fluids across the cell surface o Ribosomes ▪ Function: made up of RNA and proteins, build polypeptides and there is two types Free ribosomes in cytoplasm: manufactures proteins for cells Fixed ribosomes attached to ER: manufacture proteins for secretion Membranous organelles o Endoplasmic Reticulum ▪ Functions: synthesis of proteins, carbohydrates, and lipids, storage of synthesized materialism and create cellular membrane ▪ Difference between smooth and rough ER Smooth: no ribosomes attached, synthesizes lipids and carbohydrates Rough: surface covered in ribosomes o Golgi apparatus ▪ Function: modified and packages proteins, glycoproteins and renews or modifies the plasma membrane o Lysosomes  ▪ Function: destruction of foreign material, cleans up inside cells, and self destruction of damaged cells o Mitochondria ▪ Function: takes chemical energy from food to make ATP, produces ATP through cellular respiration, and powerhouse of cell o Nucleus ▪ General Function: largest organelle, and the cell's control center Protein Synthesis o Transcription ▪ General process: copies instructions from DNA to messenger RNA (mRNA) in nucleus o Translation ▪ Roles of mRNA, rRNA, and tRNA mRNA: moves from the nucleus through a nuclear pore and mRNA binds to ribosomal subunits rRNA: tRNA: anticodon binds to mRNA codon, one mRNA codon translates to one amino acid and enzymes join amino acids with peptide bonds ▪ General process: ribosome build polypeptide from mRNA in cytoplasm, protein folded and altered in RER and golgi apparatus and already talked about Diffusion o Why it occurs (permeability, concentration gradient) Permeability: plasma membrane allows some materials to move freely, restricts other materials based on size, electrical charge, molecular shape, and lipid solubility Concentration gradient: more solute in one part of a solvent than other o Osmosis (definition) ▪ Hypertonic vs. hypotonic Hypertonic: cell has more solutes and gain water by osmosis Hypotonic: cell has less solutes and loses water through osmosis Carrier-mediated transport o What is the difference between facilitated diffusion vs. active transport Facilitated: passive (no ATP), carries proteins, transport molecules too large to fit through channel proteins active:(primary or secondary), proteins move substrates against concentration gradient Vesicular Transport o Endocytosis vs. exocytosis Endocytosis: vesicle capture material from outside of cell Exocytosis: vesicle content released from cell Mitosis o General purpose (do not need to know phases): produce two identical daughter cells from a single parent cell, allowing for growth, development, and repair of tissues by replacing old or damaged cells throughout an organism's life Chapter 4 – Tissues  General function of 4 types of tissue - Epithelial tissue: covers exposed surfaces, lines internal passageways, forms glands - Connective tissue: fills internal spaces, supports other tissues, transports materials, stores energy - Muscle tissue: specialized for contraction - Neural tissue: carries electrical signals through body Epithelial Tissue o 5 characteristics of epithelial tissue - Cellularity: almost entirely cells - Polarity: difference between exposed and attached surface; apical surface: microvilli and cilia; basolateral surface - Attachment: basal surface bound to basement membrane - Avascularity: lack blood vessels; nutrients through diffusion or absorption - Regeneration:high rate of replacement through stem cells o Intercellular connections - Support and communication between cells ▪ Cell junctions Gap junctions - Held together by channel proteins called connexons - Allow rapid communication - Allows ions to pass - Coordinate contractions in heart muscles Desmosomes - Dense area of CAMs and intercellular cement - Like a rivet - Distribute bending twisting forces o Basement membrane - Bottom of the cell; includes basal lamina and reticular lamina o Ways to classify epithelial tissue ▪ Squamous vs cuboidal vs columnar - Squamous: thin and flat - Cuboidal: cube shape - Columnar: tall, slender hexagons ▪ Simple vs stratified ▪ Simple squamous: absorption and diffusion ▪ Stratified squamous: protects against attacks; keaton protein adds strength and water o Glands ▪ Endocrine vs exocrine glands - Endocrine: release secretions into interstitial fluid; no ducts - Exocrine: release secretions onto epithelial surfaces; through ducts ▪ Merocrine vs apocrine vs holocrine secretions - Merocrine: produced in golgi apparatus; released by vesicles (exocytosis) (ex. Sweat glands)  - - apocrine: produced in golgi apparatus; released by shedding cytoplasm (ex. Mammary glands) - Holocrine: released by cells bursting; kills gland cells; gland cells replaced by stem cells ( sebaceous oil glands) Connective tissue o 3 components of connective tissue (cells, extracellular fibers, ground substance) - Specialized cells - Solid extracellular protein fibers - Ground substance o Cells of connective tissue ▪ Fibroblasts: very common; produces matrix ▪ Fibrocytes: maintain the fibers of matrix ▪ Adipocytes: fat cells; has single, large fat droplet ▪ Mesenchymal cells: stem cells that respond to injury or infection; differentiate into fibroblasts, macrophages o Fibers of connective tissue ▪ Collagen - Long, straight, unbranched, strong, flexible; resist force in one direction (ex. Tendons and ligaments) ▪ Reticular - Network of interwoven fibers (stroma); strong, flexible; resist force in many directions; stabilizes cells and structures (ex. Sheaths around organs) ▪ Elastic - Contain elastin; branched and wavy; return to original length after stretching (ex. Elastic cartilage of the outer ear) o Ground substance - Clear, colorless, and viscous - Fills spaces between cells o Classes of connective tissue (know function) ▪ Connective tissue proper Loose Connective tissue - Fills spaces, cushion and stabilize cells, support epithelia ▪ Fluid Connective tissue Blood: watery matrix called plasma - Red blood cells (erythrocytes): transport oxygen - White blood cells (leukocytes): defend against infection - Platelets: cell fragments; clot broken vessels Lymph - Collects extracellular fluid - Monitored by immune system - Lymphocytes abundant - Mixes, nutrients, wastes - Return to veins ▪ Supporting connective tissue  Cartilage o Hyaline cartilage - Stiff, flexible support - Reduces friction between bones - Found in synovial joints, rib tips, sternum, and trachea o Elastic cartilage - Supportive but bends easily - Found in external ear and epiglottis o Fibrocartilage - Limits movement - Prevents bone to bone contact - Found between pubic bones and intervertebral discs - Pads knee joints Bone - Strong, flexible matrix - Strong calcium salt deposits - Flexible collagen fibers Muscle tissue (be able to identify from 3 characteristics: banding, # of nuclei, control) o Skeletal - Body movement o Cardiac - Only in the heart o Smooth - In walls of hollow, contracting organs - Ex: blood vessels, urinary bladder, respiratory, digestive, and reproductive tracts Neural tissue (function) o Neurons - Nerve cells - Perform electrical communication o Neurologia - Supporting cells - Repair and supply nutrients to neurons Chapter 5 – Integumentary System Cutaneous membrane o Epidermis ▪ Know there are 5 layers in palms and soles: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum ▪ Know there are 4 layers everywhere else: stratum basale, stratum spinosum, stratum granulosum, stratum corneum ▪ Layers of epidermis (know order of 5 layers: Basale, Spinosum, Granulosum, Lucidum, Corneum)  1. Stratum basale: Many stem cells called basal cells. Forms a strong bond between epidermis and dermis. Attached to basement by hemidesmosomes 2. Stratum spinosum: produced by division of stratum basale. Divides to eight to ten layers of keratinocytes. Chemicals shrink cytoplasm. Looks spiny 3. Stratum granulosum: cells stop dividing and start producing keratin and keratohyalin. 4. Stratum lucidum: clear layer. Found only in thick skin. Its glassy and dead and dehydrating 5. Stratum corneum: its a horn layer. It is the exposed surface of skin. It has 15 to 30 layers of keratinized cells. Its water resistant and it sheds and replaces every two weeks o Dermis ▪ Function of Papillary Layer - Support epithelial tissue - Dermal papillae project between epidermal ridges contain: small capillaries, lymphatic vessels, and sensory neurons ▪ Function of Reticular layer - Skin flexibility and strength o Function of Hypodermis - Stabilizes skin - Allows separate skin movement - Energy storage - 80% of all body fat Accessory structures o Hair ▪ Function - insulates , protects openings, and sensations to light touch ▪ Structures - Palms, soles, lips, and portions of external genitalia Hair follicle - Epithelial and connective tissue that make up a hair - Wrapped in connective tissue sheath - Base is surrounded by sensory nerves (root hair plexus) - Originates deep in dermis Anchor pili - Involuntary smooth muscle - Causes hair to stand up and produce goose bumps Hair parts o Hair papilla - Contains capillaries and nerves o Hair matrix - Layer of dividing basal stem cells  - Produces hair structure - Pushes hair up and out of skin o Cuticle - Protective surface layer - Still hard keratin o Exocrine glands (know basic function) ▪ Sebaceous glands - Holocrine secretion - Secrete sebum - Lubricates and protein epidermis - Inhibits bacteria ▪ Sweat glands - Apocrine and merocrine ▪ Mammary glands - Produce milk ▪ Ceruminous glands - Produce cerumen (earwax) - Protect the eardrum o Nails ▪ Function: protects finger and toes, dead cells packed with keratin ▪ Parts: nail body, nail root, and lunula Chapter 6 – Osseous Tissue and Bone Structure Structure of a long bone o Diaphysis - Bone shaft, heavy wall of compact bone or dense bone, central cavity called medullary (marrow) cavity o Epiphysis - Wide part at each end, articulation with other bones, mostly spongy bone, covered with compact bone o Metaphysis - Where diaphysis and epiphysis meet Function of 3 main components of bone tissue o Matrix - Has minerals and matrix proteins o Specialized cells ▪ Osteogenic or Osteoprogenitor cells - Mesenchymal stem cells, divide to produce osteoblasts, located in membranes, and assist in fracture repair ▪ Osteoblasts - Immature bone cells, and secrete matrix compounds (osteogenesis) Osteoid - Matrix produced by osteoblasts, mostly collagen with some other proteins, and not yet calcified to form bone ▪ Osteocytes - Mature bone cells that live in lacuna (pit) - Do not divide - Two major functions: maintain matric locally and repair damaged bone Components of dense bone o Osteon - Is the basic unit Components of spongy bone o Trabeculae - The matrix Forms an open network of trabeculae o Red bone marrow - Has blood vessels - Forms red blood cells, white blood cells, platelets - Supplies nutrients to osteocytes o Yellow bone marrow - Stores fat Bone formation and growth o Endochondral ossification ▪ General understanding of the ossification steps - Endochondral ossification 1. Chondrocytes enlarge and ide 2. Blood vessels grow around cartilage and bone forms on outside of shaft 3. Blood vessels perpetuate central cartilage 4. Remodeling occurs in shaft 5. Capillaries penetrate epiphyses 6. Cartilage reduced to think layer in metaphysis 7. All internal cartilage replaced by bone when growth ends ▪ Epiphyseal lines o Intramembranous ossification - Occurs in the dermis - Produces dermal bones: skull, mandible, and clavicle What does the process of remodeling mean? Calcium regulation o Role of Parathyroid hormone (does it increase or decrease calcium in the blood?) - Increases calcium ion levels in blood by stimulating osteoclasts, increasing intestinal absorption of calcium, and decreasing calcium excretion at kidneys o Role of Calcitonin (does it increase or decrease calcium in the blood?) - Decreases calcium ion levels in bloody by inhibiting osteoclasts, decreasing intestinal absorption of calcium, and increasing calcium excretion at kidneys Chapter 9 – Muscle Tissue Hierarchical organization of muscles (know definition of each) o Muscle: bundle of fascicles  o Fascicle: bundle of fibers o Fiber, myofiber, or muscle cell: individual muscle cell Structure of muscle fiber (know function of each) o Sarcolemma: the cell membrane of a muscle fiber, surrounds the sarcoplasm, and electrical signal across the sarcolemma beings contractions o Transverse tubules (T-tubules): tubes of sarcolemmal membrane extending into cell, transmit action potential through cell, and allow entire muscle fiber to contract simultaneously o Myofibrils: subdivision of muscle, fiber, contain bundle of contractile proteins called myofilaments, myofilaments organized into repeating units called sarcomeres o Sarcoplasmic reticulum: membranous structure surrounding each myofibril, similar in structure to smooth endoplasmic reticulum, forms chambers attached to T-tubules Structure of Myofibrils o Thin filament (actin) ▪ Tropomyosin: covers G-actin active sites and prevents actin-myosin interaction ▪ Troponin: binds tropomyosin to G-actin and controlled by Ca2+ o Thick filament (myosin): about 300 twisted myosin molecules, contain titin strands that recoil after stretching o Sarcomere: basic contractile unit of muscle fiber Mechanics of a muscle contraction (Sliding filament theory) o What occurs when an action potential reaches a triad -> the release of calcium ions from the sarcoplasmic reticulum (SR), initiating the muscle contraction process by exposing the binding sites on actin filaments, allowing myosin to bind and initiate the cross-bridge cycling that leads to muscle shortening o 6 steps of the contraction cycle 1. Contraction cycle begins: Ca arrives sarcomere 2. Active site exposure: Ca attaches to troponin (changes shape, moves, active site exposed) 3. Cross bridge formation: mypsin head binds to active sight (in a cocked back position & charged with energy) 4. Myosin head pivoting: power strike (energy released & myosin head moves, ADP released) 5. Cross bridge detachment: ATP binds to myosin head (link to actin head is broken) 6. Myosin reactivation: ATP breaks into ADP and P (myosin recocks head, cycle continues if Ca is present) Twitch definition: a single contraction that lasts about 7-100 milliseconds depending on muscle type Cardiac Muscle o Characteristics: striations, cardio muscle cells (cardiocytes), one nucleus, aerobic (high in oxygen), short white t-tubules o Function: automicity (contractions controlled by pacemaker cells, have an extended contraction time due to all the mitochondrias they have Smooth muscle tissue  o Characteristics: nonstriated, slender & spindle shape, single & central nucleus,no t-tubules or sarcomeres or tendons o Function: length-tension relationships, thick & thin filaments scattered, resting length not related to tension development (muscle adapts to length & can contract, plasticity (function over different ranges of lengths) Chapter 11 – Neural Tissue Central nervous system (CNS) o Composition (Brain and Spinal cord): Contains neural tissue, connective tissues, and blood vessels o Function: process and coordinate Peripheral nervous system (PNS) o Composition (neurons outside of CNS): All neural tissue outside the CNS o Function: deliver sensory information to the CNS and carry motor commands to peripheral tissues and systems Structure of the neuron o Cell body ▪ Parts (nucleus, rough ER, etc.): perikaryon (cytoplasm), mitochondria (produce energy), RER & ribosome (produce neurotransmitters, denser srea of RER & ribosome called nissl bodies) ▪ Neurotransmitters: chemical messengers, released at presynaptic membrane, affect receptors of postsynaptic membrane ▪ Axon hillock: thick extension of cell body o Dendrites: receive incoming signals o Axon: long structure that carries electrical signal to target ▪ Initial segment of axon: attaches to axon hillock and begin of action potential ▪ Telodendria: fine extensions of distal axon ▪ Axon or synaptic terminals: tips of telodendria, expanded end, and contain synaptic vesicles of neurotransmitters o Synapse: where neuron communicates with another cell ▪ Presynaptic cell: neuron that sends message ▪ Post synaptic cell: cell that receives messages ▪ Synaptic cleft: gap that separates the presynaptic and postsynaptic membranes 3 Functional classifications of neurons o Sensory neurons: afferent neurons that send messages to CNS o Motor neurons: efferent neurons sending messages from CNS o Interneurons: connect sensory and motor neurons in CNS Neuroglia (structure and function): Non-neural cells that preserve physical and biochemical structure of neural tissue o Central nervous system ▪ Astrocytes: Large cell bodies with many processes, create 3D framework, maintain blood-brain barrier (isolates CNS), guide neuron development, control chem concentration, form scar tissues  ▪ Oligodendrocytes: Smaller cell bodies with fewer processes, myelinated neurons o Peripheral nervous system ▪ Schwann Cells: Form myelin sheath (neurilemma) around axons Membrane potential o Electrochemical gradient: Sum of chemical and electrical gradients Resting Potential o Passive channels: always open, permeability based on electrochemical gradient o Active or gated channels: open and close in response to stimuli, at resting potential most channels are closed ▪ Chemically gated: opening in presence of specific chemicals at being site, found as neuron cell body and dendrites ▪ Voltage-gated: respond to changes in membrane potential, have activation gates and inactivation gates, part of an excitable membrane (neural axons, skeletal muscle, cardiac muscle ▪ Mechanically gated: response to membrane distortion, Found in sensory receptors (touch, pressure, vibration) Graded Potential o Characteristics of graded potential ▪ Localized: Temporary, localized change in potential - caused by opening of gated channels on dendrites, cell body ▪ Variable strength: Stronger the stimulus - greater change in membrane potential & larger area affected o What happens to cause depolarization? Membrane has to be polarized and exposed to a chemical (like Na) and depolarize which the membrane potential moves toward positive mV Action Potential o All-or-none principle: If graded potential exceeds threshold level (−60 mV), action potential is triggered, after triggered -> action potent is the same, no matter size of graded potent o 4 steps of an action potential: Step 1 - Depolarization to Threshold (Graded potential occurs, depolarization causes threshold, nearby Na voltage gated channels begin to open. Step 2 - Activation of Na+ Channels (Na rushes into cytoplasm, Rapid depolarization -> inner cytoplasm changes from very negative to positive). Step 3 - Inactivation of Na+ Channels and Activation of K+ Channels (At +30 mV, Na inactivation gated open, K channels open, repolarization begins). Step 4 - Return to Normal Permeability (K+channels begin to close -> when membrane reaches normal resting potential, K+ channels finish closing -> Membrane is hyperpolarized to −90 mV, membrane potential returns to resting level, action potential is over) Synaptic Activity o Types of synapses ▪ Electrical synapses: Direct physical contact between cells (locked together at gap junuctions), Allow ions to pass between cells (continuous local current and action potential propagation), Brain & eye & ciliary ganglia  ▪ Chemical synapses: Cells not in direct contact, neurotransmitters released into synaptic cleft, Includes most synapses between neurons & all synapses between neurons and other cells (muscles, glands) Chapter 13 – General Senses Types of Sensory receptors (know what it detects) o Nociceptors: detects pain such as extreme temperatures, mechanical damage, and dissolved chemicals (injured cells). Found in joint capsules, bone periosteum, walls of blood vessels, and superficial portions of the skin o Thermoreceptors: detects temperature sensations conducted along the same pathways as pain sensations. Located in the dermis, skeletal muscles, liver, and hypothalamus o Chemoreceptors: detects chemical changes and responds only to dissolved water-soluble substances, lipid-soluble substances, unconscious visceral receptors, and adapt quickly (period of seconds). Found in carotid glomus and the aortic arch o Mechanoreceptors: sensitive to stimuli that destroy their plasma membranes. Contains mechanically gated ions channels that open or close in response to stretching, compression, twisting, and other distortions of the membrane ▪ Baroreceptors: found in the walls of blood vessels, digestive, respiratory, and urinary tracts. Free nerve endings that branch within elastic tissues. Responds to change in pressure and adapt rapidly ▪ Proprioceptors: monitors position of joints, tension in tendons and ligaments, and state of muscular contraction ▪ Tactile receptors: detects touch sensations (shape or texture), pressure sensations (degree of mechanical distortion), vibration sensations (pulsing or oscillating pressure) Chapter 15 – Special Senses Olfaction: odorants bind to neuron o Olfactory glands: thick mucus that coats olfactory organs o Function of olfactory receptors: detect dissolved chemicals (chemicals interact with odorant-binding proteins) Gustation: information about the foods and liquids consumed o Taste receptors: (Gustatory Receptors), Distributed on tongue and portions of pharynx and larynx, receptors clustered into taste buds o Taste buds: grouped into lingual papillae o Lingual papillae: epithelial projections on superior surface of tongue ▪ Filiform papillae: provide friction, do not contain taste buds, anterior and superior on tongue ▪ Fungiform papillae: contain about 5 taste buds each ▪ Vallate papillae: up to 12 in back of tongue, contain 100 taste buds each ▪ Foliate papillae: folds on lateral side of tongue, many taste buds Eyes o Structure of eye (know functions of each) ▪ Outer fibrous layer  Sclera: (white of the eye), fibrous collagen and elastic fibers Cornea: transparent layer, refracts light ▪ Vascular layer: regulates amount of light entering eye, controls shape of lens, has blood vessels and lymphatics, secretes and reabsorbs aqueous humor Iris: regulates light entering eye o Pupil: eye opening ▪ Inner nervous layer Neural layer (retina): Inner sublayer o Photoreceptors ▪ Rods: do not discriminate light colors, highly sensitive to light ▪ Cones: provide color vision o Macula: Oval-shaped pigmented area at center of Retina, Contains densely clustered cones in small depression (fovea), area of sharpest vision o Optic disc: Circular region just medial to fovea, origin of optic nerve (blind spot with no photoreceptors) ▪ The lens Refraction: Bending of light by cornea and lens o Light detection ▪ Cones vs. rods – type of light they detect: rods are sensitive to light and respond to almost any photon, cones have ranged of sensitivity and provide color vision ▪ Visual pigments Rhodopsin: where light absorption occurs Retinal: synthesized from vitamin A Opsin: covalently bonded in rhodopsin ▪ Process of detecting light Sodium movement: At rest the cell is releasing neurotransmitters (Na gates help open by cGMP, Na cycling through the cell) Sodium channels closed: happens after PDE breaks down cDMP Neurotransmitters reduced: after Na channels close Ears o External ear ▪ Auricle: surrounds entrance to external acoustic meatus, protects opening of canal, and provides directional sensitivity ▪ External acoustic meatus: propels sounds to eardrum o Middle ear ▪ Tympanic membrane: a thin, semi transparent sheet between outer and middle ear ▪ Auditory ossicles: malleus (hammer), incus (anvil), stapes (stirrup) o Internal ear ▪ Vestibule: encloses saccule and utricle and detects gravity and linear acceleration  ▪ Semicircular canals: contain semicircular ducts and stimulated by rotation of head ▪ Cochlea: contains cochlear duct (elongated portion of membranous labyrinth) and sense of hearing o Equilibrium ▪ Hair Cells (function): basic receptors of inner ear ▪ Semicircular canals: Contain semicircular ducts, stimulated by rotation of head Process of detecting changes in head movement: sensing the fluid (endolymph) movement within their canals ▪ Utricle and Saccule: Provide equilibrium sensations Otolith: calcium carbonate crystals and pulled by gravity Process of detecting movement and equilibrium: involves tiny calcium carbonate crystals called otoconia, embedded in a gelatinous membrane within the inner ear, which shift position when the head moves, causing hair cells to bend and send signals to the brain indicating the direction and magnitude of linear acceleration or head tilt relative to gravity o Hearing ▪ Process of a soundwave being detected Tympanic membrane: vibrates Auditory ossicles: enhance vibration How a sound wave moves through cochlea: When sound waves enter the ear, a "traveling wave" moves through the fluid inside the cochlea, causing the basilar membrane to vibrate, which in turn stimulates hair cells that then send signals to the brain, allowing us to hear the sound Basilar membrane distort: hair cells become displaced, stimulate cranial nerve VIII