Fungiform Papillae

These papillae, as the name implies, are mushroom-shaped projections found all over the tongue, although they tend to be concentrated on the tip and sides. Each papillae has about five taste buds.

Vallate Papillae

These are large circular papillae with a depression in the middle. There are about twelve of them arranged in a V-Shaped row on the back of the tongue. They contain from 100 to 300 taste buds.

Occipital Lobe

This lobe lies between the occipital bone and the parieto-occipital sulcus. Its function is to receive and interpret visual signals.

Temporal Lobe

This lobe lies between the temporal bone and the lateral sulcus. It functions in memory, vison, learning, hearing, and emotional behavior.

Gyri

These are the thick folds in the surface of the cerebrum. "Gyrus" is the singular form of "gyri."

Sulci

These are the shallow grooves in the surface of the cerebrum.

Longitudinal Fissure

This fissure is a deep groove separating the cerebrum into right and left halves.

Cerebral Hemisphere

The longitudinal fissure divides the cerebrum into the right and left cerebral hemispheres

Cerebellum

This is the second largest part of the brain in mammals and the largest part of the brain in birds. The cerebellum is involved in the regulation of posture and balance, fine motor control of skeletal muscles, and repetitive movements.

Pituitary Gland

This is an endocrine gland directly attached to the hypothalamus. It is divided into anterior and posterior portions. The anterior pituitary produces hormones that regulate other endocrine glands, and directly affect target cells. The posterior pituitary functions to store and release hormones produced by the hypothalamus.

Thalamus

This structure functions to integrate all sensory information (with the exception of smell) from the body, and channels it into proper processing regions in the cerebrum.

Hypothalamus

This is the structure that is the major integration system between various organ systems and the nervous system. It coordinates activities of both the nervous and endocrine systems, and between voluntary and autonomic activities. It is attached directly to the pituitary gland.

Mammillary Body

This is a structure that processes olfactory information and contains centers for reflex movements involved in eating, such as chewing, licking, and swallowing.

Pineal Body

This is the region that regulates the day/night cycle. It also secretes the hormone melatonin, which affects sleepiness.

Corpus Callosum

This is the part of the brain that contains the nerve tracts and physically joins the two cerebral hemispheres.

Midbrain

This region that is also called the "mesencephalon." It is located above the pons and is the smallest part of the brain stem. The oculomotor, trochlear, and trigeminal cranial nerves originate in this area.

Pons

is located just above the medulla, on the brain stem. It works with the medulla to control respiration and helps regulate sleep. It is the origin for the trigeminal, abducens, facial, and vestibulocochlear cranial nerves.

Medulla Oblongata

is at the base of the brain stem. It contains nerve centers for the regulation of heart rate, blood vessel diameter, respiration, swallowing, vomiting, coughing, sneezing, and hiccoughing.

Optic Chiasma

This is a structure that is located on the bottom-center of the brain where the two optic nerves cross.

Olfactory Bulbs

These bulbs are located just below the frontal lobes. They function in the sense of smell.

Olfactory Nerve

Originates in the olfactory epithelium of the nasal cavity and terminates in the olfactory lobe.

Optic Nerve

Originates in the retina and goes to the optic chiasma. The right nerve goes to the left hemisphere and the left nerve goes to the right hemisphere.

Oculomotor Nerve

• A mixed nerve originating in the brain and terminating at the eye.
• Sensory function is to provide information on the position of the eye. Motor functions include eye and eyelid movement, controlling pupil diameter, and focusing.

Trochlear Nerve

• A mixed nerve that originates in the brain and terminates in the eye.
• Sensory function is to provide information on the position of the eye. Motor functions are lateral and inferior movement of the eye.

Trigeminal Nerve

• A mixed nerve divided into three branches. The branches originate in the face, jaws, mouth, tongue, and scalp and terminate in the pons.
• Sensory function is to transport information from various touch receptors on the face. Motor function is chewing.

Abducens Nerve

• A mixed nerve originating in the pons and innervating the lateral rectus eye muscles.
• Sensory function is to provide information on the position of the eye. Motor function is the lateral movement of the eye.

Facial Nerve

A mixed nerve originating in the pons. It innervates the muscles of the face, scalp, neck, and salivary glands.

Vestibulocochlear

• A mixed nerve originating in the inner ear and terminating in the thalamus.
• Sensory nerve functioning in hearing and equilibrium. Motor functions include a response by the head and neck to changes in equilibrium.

Glossopharyngeal Nerve

A mixed nerve with motor fibers originating in the medulla and traveling to the pharyngeal region. Sensory fibers originate in the pharyngeal region, middle and external ear, rear of the tongue, and the carotid arteries.

Vagus Nerve

A mixed nerve with motor fibers originating in the medulla and terminating in the pharyngeal region, digestive, respiratory, and cardiovascular systems. The sensory fibers originate in the thoracic and abdominal cavities, the pharyngeal region, and external ear.

Accessory Nerve

A mixed nerve originating in the medulla and the upper cervical portions of the spinal cord.

Hypoglossal Nerve

Primarily a motor nerve originating in the upper cervical portions of the spinal cord and terminating in the muscles of the tongue.

Spinal Cord

The spinal or nerve cord is located in the vertebral foramen. It begins at the foramen magnum and ends at the conus medullaris in the lumbar region. It conducts sensory impulses to the brain and motor impulses from the brain to the body.

Dura Mater

The most superficial layer of connective tissue surrounding the brain and spinal cord. It functions to protect the brain and spinal cord.

Arachnoid Layer of Meninges

Avascular layer of connective tissue that functions to protect the brain and spinal cord.

Subarachnoid Space

A space between the arachnoid and pia mater containing cerebrospinal fluid.

Pia Mater

A thin, transparent layer of connective tissue on the surface of the brain and spinal cord. It contains the blood vessels that nourish the spinal cord.

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White Matter of Spinal Cord

This area surrounds the gray matter. It is composed of both myelinated and unmyelinated axons. It is has three regions: the anterior, lateral, and posterior columns.

Gray Matter of Spinal Cord

This area is shaped like a butterfly or the capital letter "H" in cross-section. It is composed of neuron cell bodies, neuroglia cells, dendrites, and unmyelinated axons. It has three regions: the anterior, lateral, and posterior horns. The central canal is in the center of the gray matter.

Central Canal

This is a space running longitudinally through the length of the gray matter within the spinal cord, containing cerebrospinal fluid.

Dorsal Root of Spinal Nerve

These structures contain the axons of the autonomic sensory neurons.

Dorsal Root Ganglion

Located within the dorsal root, this area contains the cell bodies of somatic and autonomic sensory neurons.

Ventral Root of Spinal Nerve

This structure contains the cell bodies of the somatic motor neurons that innervate the skeletal muscles.

Spinal Nerves

These are the nerve tracks that connect the spinal cord with various regions of the body.

Afferent Impulses:

Move toward the CNS

Efferent Impulses

Move away from the CNS

Somatic Reflexes

1. Achilles Reflex
2. Corneal Reflex

controls the contraction of all skeletal muscles. __ reflexes are instinctive responses designed to protect the body, and enable the maintenance of posture and balance when standing and moving.

Autonomic Reflexes

1. Pupillary Reflex
2. Ciliospinal Reflex

They are involuntary responses that control reactions of smooth muscle, cardiac muscle, and glands.

Patellar Reflex:

• Quadriceps Femoris
• "Knee-Jerk"

Achilles Reflex:

• Gastrocnemius
• "Plantar Flexion"

Corneal Reflex:

• None
• "Blinking"

Pupillary Reflex:

• Optic and Oculomotor Nerves
• "Pupil Constriction"

Ciliospinal Reflex:

• Trigeminal and Facial Nerves
• "Pupil Dilation"

The Pupillary Reflex helps the eye adjust to:

Light

Free Nerve Endings

Unencapsulated nerve endings found widespread in superficial hairy and hairless skin. Light touch, temperature, and pain.

Hair Follicle Receptors

Unencapsulated nerve endings wrapped around a hair follicle. Light touch when the hair is displaced.

Meissner's Corpuscles

Encapsulated nerve endings found in the dermal papillae of hairless skin. Light touch and low- frequency vibration.

Merkel's Nerve Complex

Unencapsulated nerve endings found in the stratum basale of hairy and hairless skin. Pressure touch.

Lamellated or Pacinian Corpuscles

Encapsulated nerve endings in the dermis, joint capsules, some viscera, genitals, and breasts. High frequency vibration, pressure, stretch, and tickling.

Ruffini's Cylinders

Encapsulated nerve endings in the dermis and joint capsules. Pressure touch.

Supporting Cells

The supporting cells form the capsule surrounding the taste receptor cells. These cells support and protect the receptor cells.

Taste Receptor Cells

There are approximately fifty receptor cells in each taste bud. A receptor cell has a microvilli, called a "taste hair," protruding through a pore on the apical surface of the taste bud. These hairs are the receptor surface for taste stimuli.

Basal Cells

These cells are found peripherally on the base of a taste bud. They develop into supporting cells and then into receptor cells which live about ten days.

Filiform Papillae

These are small, spike-like projections found all over the tongue. They are the most abundant papillae, but lack taste buds. They roughen the tongue and aid in food manipulation.

Foliate Papillae

These papillae form parallel bands on the sides of the posterior two-thirds of the tongue. They have few taste buds.

Fungiform Papillae

These papillae, as the name implies, are mushroom-shaped projections found all over the tongue, although they tend to be concentrated on the tip and sides. Each papillae has about five taste buds.

Vallate Papillae

These are large, circular papillae with a depressions in the middle. There are about twelve of them arranged in a V-shaped row on the back of the tongue. They contain from 100 to 300 taste buds.

Olfactory Epithelium

Comprises the two olfactory organs in the nasal cavity. It contains the olfactory receptor cells.

Lamina Propria

The connective tissue beneath the olfactory epithelium.

Supporting Cells

Columnar epithelial cells found in the olfactory epithelium between the olfactory receptor cells.

Olfactory Receptor Cells

Bipolar neurons found in the olfactory epithelium. The dendrite is enlarged into a bulb-shaped "olfactory vesicle" on the surface of the olfactory epithelium. The olfactory vesicle has cilia called "olfactory hairs" which project into the mucus on the surface of the epithelium. Odors cause depolarization on these hairs.

Basal Cells

The cells that replace lost or damaged olfactory receptor cells at the base of the olfactory epithelium. (They are a notable exception to the rule of thumb that neurons do not replicate).

Bowman's Gland

These are mucus glands found in the lamina propria that moisten the olfactory epithelium and dissolve odor molecules.

Auricle or Pinna

The fleshy, cartilaginous external ear flap located on the side of the head. It functions to collect sound waves and direct them into the external auditory canal.

External Auditory Canal

The passageway that directs sound waves from the auricle to the tympanic membrane.

Tympanic Membrane

Commonly called the "eardrum." It separates the outer and middle ears. The eardrum vibrates when struck by sound waves and mechanically transfers the sound to the middle ear.

Ceruminous Glands

These glands secrete cerumen, or earwax, into the external auditory canal. They are located at the base of hairs that line the canal. In combination with the hair, cerumen helps prevent foreign substances from reaching the delicate tympanic membrane.

Malleus

An ossicle commonly called the "hammer." It is attached to the inside surface of the tympanic membrane. It articulates with the incus and transmits vibrations from the tympanic membrane to the incus.

Incus

An ossicle commonly called the "anvil." It articulates with the malleus and stapes and transmits vibrations from the malleus to the stapes.

Stapes

An ossicle commonly called the "stirrup." It articulates with the incus and the oval window and transmits vibrations from the incus to the oval window.

Oval Window

An opening between the middle and inner ear. The stapes attaches to the membrane over the oval window and transfers the vibrations to the fluid in the inner ear. The membrane over the oval window is 22 times smaller than the tympanic membrane. This size difference magnifies the vibrations and enables a person to hear low amplitude sounds.

Round Window

An opening directly below the oval window. Covered by a secondary tympanic membrane. Bulges out into the middle ear to dissipate the pressure waves within the cochlea, after they have been detected by the inner ear. Eustachian tube A tube connecting the middle ear and the nasopharynx. It equalizes the air pressure in the middle ear with that of atmospheric pressure, enabling the tympanic membrane to vibrate freely.

Eustachian Tube

A tube connecting the middle ear and the nasopharynx. It equalizes the air pressure in the middle ear with that of atmospheric pressure, enabling the tympanic membrane to vibrate freely.

Stapedius

A small skeletal muscle that protects the oval window by dampening the vibration of the stapes in response to loud noises.

Tensor Tympani

A small skeletal muscle that limits movement of ossicles and increases tension of the tympanic membrane to prevent damage in response to loud, prolonged noises.

Bone Labyrinth

A series of interconnected passageways in the temporal bone.

Membranous Labyrinth

A series of interconnected, fluid-filled tubes found within the bony labyrinth.

Cochlea

A part of the bony labyrinth resembling a snail shell. It contains the cochlear duct.

Cochlear Duct

A part of the membranous labyrinth found within the cochlea. It contains the hearing receptor cells.

Vestibule

A part of the bony labyrinth containing the saccule and utricle.

Saccule and Utricle

A pair of membranous sacs found within the vestibule that contain the receptor cells for gravity and linear acceleration.

Semicircular Canals

A part of the bony labyrinth containing the semicircular ducts.

Semicircular Ducts

A series of three fluid-filled ducts found within the semicircular canals. They are oriented at right angles to each other on three planes. The receptors in the ducts provide information on the position of the head and body in space, acceleration, and deceleration.

Eyebrows

Located superior to the eye, they partially shade the eyes, and protect them from sweat.

Eyelids

Located over the eye. The eyelids blink to moisten the eye and sweep foreign substances from the eye's surface.

Eyelashes

Located on the margin of the eyelids. They prevent foreign substances from entering the eye.

Lacrimal Apparatus

Composed of the lacrimal (or tear) gland and lacrimal ducts. Secretions or tears from the gland moisten the eye and washes away foreign substances.

Conjuctiva

An epithelial covering on the inside of the eyelid and the anterior surface of the eye. Helps keep the cornea moist and clean.

Oblique Eye Muscles

The superior oblique rotates the eye downward and medially. The inferior oblique rotates the eye upward and medially.

Rectus Eye Muscles

The four muscles are the superior, inferior, medial, and lateral rectus muscles. These muscles move the eye up, down, medially, and laterally.

Sclera

Commonly called the "white" of the eye. A tough, tendon-like layer continuous with the dura mater of the brain around the optic nerve. It shapes the eye and is the insertion point for the six muscles that control eye movements.

Cornea

The most anterior layer of the eye that is continuous with the sclera. Transparent to allow light into the eye. Well-supplied with nerve endings for pain, reflex blinking, and to stimulate lacrimal secretions. It also lacks blood vessels.

Choroid

Separates the fibrous and sensory tunics. Contains a dense capillary bed that provides oxygen and nourishment to the eye. Also contains many melanocytes which give the choroid its dark appearance.

Iris

Lies just beneath the cornea. The layer to which we attribute eye color. Composed of two layers of pupillary muscles that control the diameter of the pupil, and thus the amount of light entering the eye.

Pupil

The round central opening in the center of the eye.

Ciliary Body

A thick ring of tissue attached to, and lies just beneath, the iris. Anchored at its margins by the choroid. Holds the lens in place beneath the iris and centered on the pupil. Contains the ciliary muscle, a smooth muscle that attaches to the lens. Changes the lens shape to focus light onto the retina.

Lens

Located beneath the iris and held in the center of the pupil by suspending ligaments extending from the ciliary body. Transparent and convex on its outer and inner surfaces. Focuses an image on the retina by changing shape under the influence of the ciliary muscles.

Retina

The delicate, two innermost layers of the eye. The neural layer contains photoreceptors and neurons that react to light and transmit and integrate visual signals. Beneath the neural layer lies the pigmented layer. It absorbs light that has passed through the neural layer to prevent the light from bouncing back and causing "visual echoes."

Rods

Photoreceptor cells that are very sensitive to light. They enable us to see shades of gray in dim light.

Cones

Photoreceptor cells responsible for high acuity color vision. They only operate in bright light. There are three types of cones: sensitive to red, green, or blue light.

Bipolar Neurons

These cells form a synapse with the dendrites of the rods and cones. They transmit nerve impulses to the ganglion cells.

Ganglion Cells

These cells form a synapse with the axons of the bipolar neurons. The axons combine to form the optic nerve, which sends nerve impulses to the brain.

Optic Disc

The area of the retina where the optic nerve leaves the eye. It is not covered by the retina. It is literally a blind spot in the eye.

Optic Nerve

It transmits visual information from the eye to the brain.

Fovea Centralis

The portion of the retina that is responsible for sharp central vision. Humans use this region for any activity that requires detailed vision, such as driving.

What might cause some areas of the body to be more sensitive than others?

The amount of sensory neurons that are present in that specific area.

The Five Primary Tastes:

• Salty
• Sweet
• Bitter
• Sour
• Umami

Trichromacy

Able to see all three primary colors

• Red
• Green
• Blue

Monochromacy

are truly "color blind". They are unable to distinguish any color. They are only capable of seeing various degrees of lightness and darkness, so to them the world appears in shades of gray, black, and white.

Dichromacy

are able to distinguish some colors. There are three types of dichromacy. Protanopia and deuteranopia are deficiencies in the red and green pigments. Those with red-green deficiencies have difficulty distinguishing between reds, greens, and yellows but can discriminate between blues and yellows.

The Blind Spot and Snellen Visual Acuity Tests, Test In:

Color Blindness and Blind Spotting

Brain:

Inner Brain

Spinal Nerve:

Reflex Arc:

Olfaction:

Ear:

Eye:

Inner Workings of an Eye: