General Senses: touch, pressure, vibration, pain, temperature, proprioception (perception of position and movement of body parts), chemical and fluid pressure (ie: blood pressure).
Somatic Sensations: are detected by peripheral receptors in skin, muscle, tendons and joints.
Visceral Sensations: are detected by deep receptors in the walls of internal organs and blood vessels.
Special Senses: include olfaction (smell), gestation (taste), vision, hearing and equilibrium (body orientation). Receptors for these sensations are localized to specific regions in the head and have a complex structure. This information must travel along complex pathways to reach the CNS.
Olfaction: sense of smell.
Gustation: sense of taste.
Vision: sense of sight.
Hearing: sense of hearing.
Equilibrium: a dynamic state in which two opposing forces or processes are in balance.
Olfactory Epithelium: contains the olfactory sensory receptors; covers superior portion of the nasal cavity and consists of 3 cell types:
- Olfactory receptor cells
- Supporting cells
- Basal cells
Olfactory Receptor Cells: Bipolar neurons that are stimulated by chemical substances (odorants) in the nasal cavity.
Supporting Cells: columnar epithelial cells that surround the olfactory receptors.
Basal Cells: are interspersed between the bases of the supporting cells and divide regularly to produce new olfactory receptor cells
Olfactory Foramina: narrow openings that pass through the cribriform plate. These passageways transmit the unmyelinated axons of the olfactory nerve (cranial nerve I (1)).
Cilia: a slender organelle that extends above the free surface of an epithelial cell and generally undergoes cycles of movement, composed of a basal body and microtubules in a 9+2 array.
Olfactory Glands: located in the lamina propria (connective tissue) secrete mucus onto the surface of the olfactory epithelium.
Papillae: located on the tongue, taste buds are in the epithelium of surface projections.
Taste Buds: ovoid structures that resemble a flower bud and contain sensory receptors. Composted of 3 different cells types: Basal, Transitional and Gustatory cells.
Taste Pore: on the taste bud and open to oral cavity.
Gustatory Cells: the last stage from Basal Cells dividing into daughter cells. Receptors.
Taste Hairs: microvilli located on supporting and gustatory cells.
Facial Nerve (Cranial Nerve VII (7)): supplies the taste buds on the anterior two-thirds of the tongue.
Glossopharyngeal Nerve (Cranial Nerve IX (9)): innervates the posterior one-third of the tongue.
Vagus Nerve (Cranial Nerve X (10)): innervates the taste buds on the soft palate, pharyngeal wall and epiglottis.
Gustatory Nucleus: (solitary) gets info on taste and medulla oblongata.
Thalamus: the walls of the diencephalon.
Primary Gustatory Cortex: receives information from taste receptors of the tongue and pharynx, lies in the anterior portion of the insula and adjacent portions of the frontal lobe.
Five Primary Taste Sensations: sweet, sour, salty, bitty and umami (beef).
Oral Cavity: mouth.
Pharynx: Throat. Muscular passageway shared by the digestive and respiratory tract.
Soft Palate: Posterior soft tissue portion of the palate – which separates the nasal cavity from the oral cavity.
Epiglottis: A blade-shaped flap of tissue reinforced by cartilage that is attached to the dorsal and superior surface of the thyroid cartilage; folds over the entrance to the larynx during swallowing.
Fibrous Tunic: the outermost layer of the eye, composed of sclera and cornea.
Vascular Tunis (Uvea): made up of the iris, ciliary body and choroid. Contains numerous blood vessels and the intrinsic (smooth) muscles of the eye.
Neural Tunic (Retina): inner most layer of the eye. Consists of a thin outer layer called the pigmented part and a thick inner layer called the neural part.
Pigmented Layer: (located in the Retina) absorbs light that passes through the neural part, preventing light from bouncing back through the neural part and producing visual “echoes.”
Nervous Layer: (located in the Retina) contains supporting cells and neurons that perform preliminary processing and integration of visual information.
Melanocytes: A specialized cell in the deeper layers of the stratified squamous epithelium of the skin; responsible for the production of melanin.
Melanin: the yellow-brown pigment produced by the melanocytes of the skin.
Photoreceptor Cells: form the outermost layer of the retina – two types of cells: rods and cones.
Rods: highly sensitive to light, do not discriminate among colors of light (we can see in dimly lit rooms).
Cones: provide color vision. Three cone types; sees better in bright light.
Bipolar Cells: located in the middle layer and form synapses with the photoreceptive cells.
Ganglion Cells: form the innermost layer, synapse with the bipolar cells.
Optic Nerve: is formed by the axons of the ganglion cells.
Optic Canals: permit passage of the optic nerves from the eyes to the brain.
Optic Chiasm: The crossing point of the optic nerves.
Optic Tracts: the tract over which nerve impulses from the retina are transmitted between the optic chiasm and thalamus.
Superior Colliculi: receive visual inputs from the lateral geniculate nucleus of the thalamus on that side. Integrate visual information with other sensory inputs; initiate reflex responses to visual stimuli. (Subdivision gray matter).
Optic Radiation: the bundle of projection fibers linking the lateral geniculates with the visual cortex.
Visual Cortex: (occipital lobe) receives visual information.
Tarsal Glands: along the inner margin of the eyelid, these modified sebaceous glands secrete a lipid-rich product that helps keeps eyelids from sticking together.
Palpebral Fissure: the gap that separates the free margins of the upper and lower eyelids.
Cornea: the transparent portion of the fibrous tunic of the anterior surface of the eye.
Iris: a contractile structure, made up of smooth muscle, which forms the colored portion of the eye.
Pupil: the opening in the center of the iris through which light enters the eye.
Sclera: the fibrous outer layer of the eye that forms the white area of the anterior surface; a portion of the fibrous tunic of the eye.
Medial Canthus: corner of the eye, closest to the nose.
Lateral Canthus: corner of the eye, closest to the ear.
Lacrimal Caruncle: small reddish mass of soft tissue at the medial canthus. Glands in this structure produce mucus that often accumulates while sleeping.
Conjunctiva: a thin, protective mucous membrane that lines the inner surface of the eyelids and curves onto the anterior surface of the eye to cover the sclera.
Palpebral Conjunctiva: inner surface of eyelids.
Ocular Conjunctiva: anterior surface of the eye.
Lacrimal Gland: produces watery, alkaline tears.
Lacrimal Apparatus: made up of the lacrimal gland and accessory structures regulate the movement of tears across the surface of the eye and drain it into the nasal cavity.
Lysozyme: antibacterial enzyme contained in tears.
Lacrimal Puncta: two small pores that tears from your blinking drain too.
Lacrimal Sac: catches tears drained from the lacrimal puncta.
Lacrimal Fossa: small groove traveling along the lacrimal bones – marks the location of the lacrimal sac.
Nasolacrimal Duct: receives tears from the lacrimal sac, passes through a canal in the maxilla and drains into the nasal cavity.
Extrinsic Eye Muscles (6): (pg. 172)
- Medial Rectus
- Lateral Rectus
- Inferior Rectus
- Superior Rectus
- Inferior Oblique
- Superior Oblique
Choroid: a thin layer of tissue that contains numerous small blood vessels. It’s densely populated with melanocytes. The melanin produced by these cells prevents incoming light waves from being reflected back out of the eye. The middle vascular layer in the wall of the eye.
Lens: the transparent refractive structure that is between the iris and the vitreous humor.
Optic Disc/Blind Spot: a circular region just medial to the fovea. No photoreceptors or other structures typical of the rest of the retina.
Macula Lutea/Fovea: The portion of the retina that provides the sharpest vision because it has the highest concentration of cones (no rods).
Posterior Cavity: (vitreous chamber) eyeball is hollow and has two cavities.
Vitreous Humor: jelly-like substance.
Anterior Cavity: made up of the posterior and anterior chambers.
Aqueous Humor: the watery fluid in the anterior cavity.
Presbyopia: a condition as a person ages, the elasticity of the lens decreases and focusing on close objects become more difficult.
Near-Point Accommodation: test elasticity of the lens = the distance from the eyes at which an object begins to be blurred or distorted.
Emmetropia: normal vision.
Myopia: near-sighted.
Hyperopia: far-sighted.
Astigmatism: the degree of curvature in the cornea or lens varies from one axis to another; the light passing through the cornea or lens is not refracted properly, the visual image will be distorted.
Color blindness: can’t distinguish certain colors – this occurs when one or more classes of cones are nonfunctional.
Labyrinth: a maze of passageway; the structures of the internal ear.
Maculae (singular = Macula): a receptor complex, located in the saccule or utricle of the inner ear, which responds to linear acceleration or gravity.
Static Equilibrium: linear movements and responds to gravitational forces, walking forwards/backwards and jumping.
Dynamic Equilibrium: change in angular acceleration or deceleration; making a turn in a car or performing gymnastics.
Stereocilia: elongate microvilli; characteristic of the epithelium of the epidiymis, portions of the ductus deferens and in the internal ear.
Kinocilium: a single, large cilium.
Cerebellum: the posterior portion of the metencephalon, containing of the cerebellur hemispheres; includes the arbor vitae, cerebellar nuclei and cerebellur cortex.
Medial Geniculate Bodies: located in the thalamus.
Auricle/Pinna: a broad, flattened process that resembles the external ear; in the ear the expanded projecting portion that surrounds the external auditory meatus (external part of ear).
Helix: inferior fleshy lobule (earlobe).
Ceruminous Glands: Integumentary glands that secrete ceruman (wax).
Ceruman: the waxy secretion of the ceruminous glands along the external acoustic meatus.
Vestibular Membrane: separates the cochlear duct from the vestibular duct.
Basilar Membrane: separates the cochlear duct from the tympanic duct.
Spiral Ganglion: contains neuron cell bodies of the cochlear division of the vestibulocochlear nerve (cranial nerve VIII (8)).
Tectorial Membrane: arches over the hair cells. The stereocilia of the hair cells are in contact with this membrane.
Conductive Deafness: can occur if the transmission of sound waves is disturbed in the external acoustic canal at the eardrum or along the bony ossicles.
Sensorineural Deafness: is the result of damage along the neural pathway for hearing.
Rinne Test: testing if sound conduction along the ear ossicles are impaired.
Weber Test: determines if you have conductive or sensorineural deafness (tuning fork on head).
