AMA 171 - Anatomy & AMA 171 - Anatomy & Physiology/Medical Physiology/Medical

Terminology/PathologTerminology/Pathology 2 Skin and Sensesy 2 Skin and Senses

Skin: (Integumentary Skin: (Integumentary System)System)

Interesting fact:Interesting fact: weighs 8-10lbs and weighs 8-10lbs and covers an area of 22 square feet (in an covers an area of 22 square feet (in an average adult)average adult)

Functions: Functions: Covers and protects the internal organs Covers and protects the internal organs

and tissuesand tissues Produces important secretions: oil and Produces important secretions: oil and

sweat to lubricate and cool the bodysweat to lubricate and cool the body Contains nerves that are receptors for Contains nerves that are receptors for

sensations such as pain, temperature, sensations such as pain, temperature, pressure and touchpressure and touch

Thermoregulation of the bodyThermoregulation of the body

Structure (layers of the Structure (layers of the skin):skin):

Epidermis:Epidermis: outermost layer made of squamous outermost layer made of squamous epithelial cells; the basal layer of the epidermis is epithelial cells; the basal layer of the epidermis is always growing and multiplyingalways growing and multiplying

Dermis:Dermis: middle layer composed of blood and middle layer composed of blood and lymph vessels, nerve fibers and accessory lymph vessels, nerve fibers and accessory organs, such as hair follicles, sweat and organs, such as hair follicles, sweat and sebaceous glandssebaceous glands

Subcutaneous:Subcutaneous: deepest layer specializing in the deepest layer specializing in the formation of fat; important in the protection of formation of fat; important in the protection of the deeper tissues of the body, as a heat the deeper tissues of the body, as a heat insulator and for energy storageinsulator and for energy storage

Accessory organs: hair, Accessory organs: hair, nails & glandsnails & glands

Hair:Hair: fibers composed of keratin, a hard protein fibers composed of keratin, a hard protein Nails:Nails: hard keratin plates covering the last bones of each hard keratin plates covering the last bones of each

toe and fingertoe and finger

Glands: Glands: Sebaceous (oil):Sebaceous (oil): found almost everywhere, except hands found almost everywhere, except hands

and feet. Lubricate the skin through the hair follicle and and feet. Lubricate the skin through the hair follicle and minimize water loss from the body; influenced by sex minimize water loss from the body; influenced by sex hormoneshormones

Sweat:Sweat: most numerous on hands and feet but found on most numerous on hands and feet but found on almost all body surfaces. Almost pure water with dissolved almost all body surfaces. Almost pure water with dissolved materials such as salt; odor comes from bacteria, not materials such as salt; odor comes from bacteria, not sweat. Sweat (perspiration) cools the body as it evaporates sweat. Sweat (perspiration) cools the body as it evaporates into the air.into the air.

Sense Organs:Sense Organs: Receptors that Receptors that are activated by stimuli from the are activated by stimuli from the external or internal environment.external or internal environment.

Eye:Eye: light rays enter the eye and are light rays enter the eye and are sent to the cerebral cortex of the brain, sent to the cerebral cortex of the brain, fusing to form a visual sensation with fusing to form a visual sensation with three-dimensional effectthree-dimensional effect

Ear:Ear: sound waves are received by the sound waves are received by the ear and sent to the auditory region of ear and sent to the auditory region of the brain in the cerebral cortexthe brain in the cerebral cortex

Structure of the eyeStructure of the eye Cornea:Cornea: fibrous tissue covering pupil and iris, light enters here first, is fibrous tissue covering pupil and iris, light enters here first, is

bent or refracted bent or refracted

Anterior chamber:Anterior chamber: contains aqueous humor a fluid produced by the contains aqueous humor a fluid produced by the ciliary body to nourish the eye and help maintain its shapeciliary body to nourish the eye and help maintain its shape

Pupil:Pupil: dark center of the eye, light rays enter here after passing through dark center of the eye, light rays enter here after passing through the corneathe cornea

Iris:Iris: colored portion of the eye, contains muscles that constrict pupil to colored portion of the eye, contains muscles that constrict pupil to regulate lightregulate light

Conjuctiva:Conjuctiva: membrane that lines the eye and eyelids; clear and colorless membrane that lines the eye and eyelids; clear and colorless unless irritatedunless irritated

Sclera:Sclera: white of the eye, provides nourishment via blood vessels white of the eye, provides nourishment via blood vessels

Choroid:Choroid: dark brown membrane inside of sclera, contains blood vessels dark brown membrane inside of sclera, contains blood vessels

Lens:Lens: changes shape to refract light and to flatten or round the lens for changes shape to refract light and to flatten or round the lens for distance or close vision (accommodation) distance or close vision (accommodation)

Structure of the eye cont…Structure of the eye cont… Ciliary body:Ciliary body: muscles that control the lens muscles that control the lens

Vitreous humor:Vitreous humor: jelly-like fluid that helps maintain eye’s jelly-like fluid that helps maintain eye’s shapeshape

Retina:Retina: sensitive nerve layer of the eye, contains rods and sensitive nerve layer of the eye, contains rods and cones that are receptor cells responsible for color and central cones that are receptor cells responsible for color and central visionvision

Optic nerve:Optic nerve: chemical change from rods and cones cause chemical change from rods and cones cause nerve impulses to send visual signal to brain through this nerve impulses to send visual signal to brain through this nervenerve

Optic disc:Optic disc: region where optic nerve meets the retina region where optic nerve meets the retina

Macula:Macula: area that contains the fovea centralis area that contains the fovea centralis

Fovea centralis:Fovea centralis: depression in macula that is the location of depression in macula that is the location of the sharpest vision in the eyethe sharpest vision in the eye

Structure of the ear: Structure of the ear: three three regions of the earregions of the ear

Outer ear:Outer ear: conducts sound waves conducts sound waves Pinna (auricle): flap of the earPinna (auricle): flap of the ear External auditory meatus (auditory canal): ear canal that External auditory meatus (auditory canal): ear canal that

secretes ceruman (ear wax)secretes ceruman (ear wax)

Middle ear:Middle ear: conducts sound waves conducts sound waves Tympanic membrane (eardrum): sounds waves make this Tympanic membrane (eardrum): sounds waves make this

vibratevibrate Ossicles: three small bones that are vibrated by the sound Ossicles: three small bones that are vibrated by the sound

on the tympanic membrane: Maleus, Incus & Stapeson the tympanic membrane: Maleus, Incus & Stapes Oval window: vibration from stapes touches this Oval window: vibration from stapes touches this

membrane that separates the middle and inner earmembrane that separates the middle and inner ear

Inner ear (labyrinth):Inner ear (labyrinth): receives auditory waves and relays receives auditory waves and relays them to the brainthem to the brain

Cochlea: looks like a shell; contains liquids that transmit Cochlea: looks like a shell; contains liquids that transmit the sound waves/vibrationsthe sound waves/vibrations

Auditory nerve fibers: connect the cochlea to the brain so Auditory nerve fibers: connect the cochlea to the brain so the brain “hears” soundsthe brain “hears” sounds