Anatomy Exam 3

Touch

Large group of general senses

Special sensory receptors

Localized to the head, receptors are distinct receptor cells

Chemical sense

Gustation and olfaction

Chemoreceptors

Chemical senses receptors, respond to chemicals

Taste receptors

Taste buds

Taste bud locations

Fungiform papillae, vallate papillae, and foliate papillae

Taste bud cell types

Gustatory epithelial cells and basal epithelial cells

Foliate, vallate, fungiform

Papillae back to front

Taste qualities

Sweet, sour, salty, bitter, umami

Facial, glossopharyngeal, and vagus nerves

Gustatory pathway nerves

Gustatory pathway

Facial, glossopharyngeal, vagus nerve to solitary nucleus in medulla to thalamus to gustatory area of the cerebral cortex in the insula

Olfactory epithelium

Pseudostratified columnar, olfactory sensory neurons, supporting epithelial cells, and olfactory stem cells

Olfactory pathway

Olfactory cilia → apical dendrite → Bipolar (olfactory sensory neurons) → axons gather into filaments of the olfactory nerve → Cribriform plate of ethmoid bone → Olfactory bulb → mitral cells → Olfactory tract

Limbic system and primary cortext

Where does the olfactory tract lead to

Olfactory placodes

Where does the olfactory epithelium develop from

Stimulation by gustatory nerves

Taste buds develop upon

Anosmia

Absence of the sense of smell

Uncinate fits

Distortion of smells or olfactory hallucinations

Eyebrows

Coarse hairs on the superciliary arches

Eyelids (palpebrae)

Separated by palpebral fissure

Lacrimal caruncle

Reddish elevation at the medial angle

Tarsal plates

Connective tissue within the eyelids

Tarsal glands

Modified sebaceous glands that make tears and lubricates eye

Conjuctiva

Transparent mucous membrane

Palpebral conjunctiva

Inner surface of eyelids

Bulbar conjunctiva

Anterior surface of eye

Conjunctival sac

Space between eye surface and eyelids

Lacrimal apparatus

Keeps the surface of the eye moist

Lacrimal gland

Produces lacrimal fluid

Lacrimal sace

Fluid empties into nasal cavity, nasolacrimal duct to inferior meatus of nasal cavity

Orbicularis oculi

Muscle that closes the eye

Levator palpebrae superioris

Muscle that voluntarily opens the eye

Oculomotor nerve

Innervated the levator palpebrae muscle

Ciliary glands

Associated with hair follicles of the eyelashes

Annular ring

Origin of the 4 rectus muscles

Lateral rectus muscle

Moves the eye laterally, CNVI (abducens)

Medial rectus muscle

Moves the eye laterally, CNIII (oculomotor)

Superior rectus muscle

Elevates and turns the eye medially, CNIII (oculomotor)

Inferior rectus muscle

Depresses and turns the eye medially, CNIII (oculomotor)

Inferior oblique muscle

Elevates and turns the eye laterally, CNIII (oculomotor)

Superior oblique muscle

Depresses and turns the eye laterally, CNIV (trochlear)

Trochlea sling

Acts as a sling for the superior oblique muscle

Components of the eye functions

Protect and support photoreceptors, and gather, focus, and process light into images

Anterior pole

Most anterior part of the eye

Posterior pole

Most posterior part of the eye

External walls of the eye

Composed of 3 tunics

Internal cavity of the eye

Contains fluid (humors)

Fibrous layer

Most external, sclera and cornea

Sclera

Posterior 5/6 of the eye, white, opaque region, provides shape and an anchor for eye muscles

Cornea

Fibrous layer anterior 1/6 of the eye

Scleral venous sinus

Allows aqueous humor to drain

Vascular layer of eye

Middle coat, choroid, ciliary body, and iris

Choroid

Vascular, darkly pigmented, posterior 5/6 of the eye, middle later, brown because of melanocytes

Choroid function

Prevents scattering of light rays within the eye

Ciliary body

Thickened ring of tissue, encircles the lens, composed of ciliary muscle and ciliary process

Ciliary muscle

Expands and contracts the lens of the eye

Ciliary process

Posterior surface of the ciliary body makes the aqueous humor

Ciliary zonule (suspensory ligaments)

Attached around the circumference of the lens

Iris

Colored part of the eye, attached to ciliary body, smooth muscle

Pupil

Round, central opening of the iris

Sphincter pupillae muscle

Parasympathetic, contracts, makes the pupil smaller

Dilator pupillae muscle

Sympathetic, contracts, increases pupil size

Pupillary light reflex

Protective response of pupil constriction to bright light

Inner layer of the eye

Retina

Retina

Deepest tunic, 2 layers

Pigmented layer

First layer of the retina, single layer of melanocytes

Neural layer

Anterior layer of the retina, sheet of nervous tissue

Photoreceptor cells, bipolar cells, ganglion cells

Neural layer cells order of signaling

Ganglion cells

Generate eye nerve impulses, axons run along internal surface of the retina and converge to form the optic nerve

Photoreceptors

Rod and cones, neurons

Rods

Sensitive to light, gives vision in low light

Cones

Best in bright light, high acuity color vision

Receptor regions

Outer region of rods and cones, light-absorbing pigments

Ora serrata

Neural layer ends at the posterior margin of the ciliary body, pigmented layer covers ciliary body and posterior surface of the iris

Macular lutea

Mostly cones

Fovea centralis

Only cones, highest visual acuity

Optic disc

Blind spot

Capillaries in the choriod

Blood supply to the outer 1/3 of the retina

Central artery and vein of the retina

Blood supply to the inner 2/3 of the retina

Vitreous humor

In the posterior segment of the eye, clear, jellylike, transmits light, supports the posterior surface of the lens, maintains intraocular pressure

Anterior chamber

Between cornea and iris

Posterior chamber

Between iris and lens

Aqueous humor

In the anterior segment of the eye, renewed continuously, formed as blood filtrate, and provides nutrients to the lens and cornea

Visual pathways

To the cerebral cortex, midbrain, and diencephalon

Visual pathway to the cerebral cortex

Optic tracts send axons to the lateral geniculate nucleus of the thalamus, synapse with thalamic neurons, fibers of the optic radiation reach the primary visual cortex

Depth perception

Partial decussation of visual axons

Visual pathway to the midbrain

Superior colliculi, pretectal nuclei, and suprachiasmatic nuclei

Superior colliculi

Visual reflexes

Pretectal nuclei

Pupilaary light reflexes

Suprachiasmatic nuclei

Synchronizing biorhythms with daylight cycle

Retinopathy of prematurity

Blood vessels grow within eyes of premature infants, vessels have weak walls leading to hemorrhaging and blindness

Trachoma

Contagious infection of the conjunctiva