SJSU SP24 BIOL-65 Lecture Exam 3

autonomic nervous system

a motor division of the nervous system that innervates glands, smooth muscle, and cardiac muscle; consists of sympathetic and parasympathetic divisions and functions largely without voluntary control

visceral (organ) motor system

involuntary control of effectors: glands, cardiac muscle, smooth muscle

visceral reflexes

unconscious, automatic, stereotypes responses of visceral effectors to stimuli

sympathetic division

it increases alertness, heart rate, blood pressure, pulmonary airflowm blood glucose concentration, and blood flow to cardaic and skeletal muscle; also reduces blood flow to the skin and digestive tract; referred to as "fight or flight"

parasympathetic division

has a calming effect on many body functions; associated with reduced energy expenditure and normal bodily maintenance, including such functions as digestion and waste elimination; "resting and digesting"

autonomic tone

balance between activity of sympathetic and parasympathetic nervous systems

Preganglionic fiber

begins with a neurosoma in the brainstem or spinal cord; axon extends to an autonomic ganglion somewhere outside the CNS; meets the neurosoma of a second neuron and secretes the neurotransmitter acetylcholine to stimulate the latter; myelinated

postganglionic fiber

from the axon of the second neuron, leaves the ganglion and extends the rest of the way to the target organ or cells; secretes either ACh or norepinephrine; can have excitatory or inhibitory effect on target cells; unmyelinated

Somatic effectors

Skeletal muscle

Autonomic effectors

glands, smooth muscle, cardiac muscle

Somatic control

Voluntary

Autonomic control

Involuntary

Somatic Efferent pathways

one nerve fiber from CNS to effector; no ganglia

Autonomic Efferent pathways

two nerve fibers from CNS to effector; synapse at a ganglion

Somatic effect on target cells

Always excitatory

Autonomic Effect on target cells

Excitatory or inhibitory

Thoracolumbar division

another name for sympathetic division; arises from the thoracic and lumbar regions of the spinal cord; preganglionic neurosomas are in lateral horns of spinal cord; short preganglionic fibers and long postganglionic fibers; sympathetic chain ganglia from cervical to coccygeal levels

Craniosacral division

also known as parasympathetic division; long preganglionic fibers and short postganglionic fibers; terminal ganglia are in or near target organ

enteric nervous system

nervous system of digestive tract; innervates smooth muscle and glands; regulates motility of esophagus, stomach, and intenstines; regulates secretion of digestive enzymes and acid

Horner syndrome

unilateral pupillary constriction, sagging of eyelid, and flushing of skin due to lesions in sympathetic division

Raynaud disease

Paleness, cyanosis, and pain in digits when cold or stressed due to excessive vasoconstriction; most common in young women

General Senses

Senses such as touch, heat, cold, pain, vibration, and pressure, mediated by relatively simple sense organs that are distributed throughout the body

Thermoreceptors

respond to heat and cold

Photoreceptors

the eyes, respond to light

Chemoreceptors

respond to chemicals, including odor, tastem and body fluid composition

Nociceptors

pain receptors; respond to tissue damage resulting from trauma (blows, cuts), ischemia (poor blood flow), or excessive stimulation by agents such as heat and chemicals

Mechanoreceptors

respond to physical deformation of a tissue or cell caused by touch, pressure, stretch, tension, or vibration; includes organs of hearing and balance and many receptors of the skin, viscera, and joints

Unencapsulated Endings of General Senses

Free nerve endings, Tactile discs, hair receptors

Free nerve ending

a bare sensory nerve ending, lacking associated connective tissue or specialized cells; includes receptors for heat, cold, and pain

Locations of Free nerve endings

Widespread, especially in epithelia and connective tissues

Modality of Free nerve endings

Pain, heat, cold

Tactile discs

receptors for light touch and pressure on the skin; a flattened nerve ending associated with a specialized tactile cell at the base of the epidermis

Locations of Tactile discs

Stratum basale of epidermis

Modality of Tactile discs

Light touch, pressure

Hair receptors (root hair plexuses)

free sensory nerve endings entwined around a hair follicle, responsive to movement of the hair

Locations of Hair receptors

Around hair follicle

Modality of Hair receptors

Light touch, movement of hairs

Encapsulated Nerve Endings

Tactile corpuscles, End bulbs, Bulbous corpuscles, Lamellar corpuscles, Muscle spindles, Tendon organs

Tactile corpuscles

receptors for light touch and texture; tall, ovoid to pear-shaped, and consist of two or three nerve fibers meandering upward through a mass of flattened Schwann cells.

Location of Tactile corpuscles

Dermal papillae of fingertips, palms, eyelids, lips, tongue, nipples, and genitals

Modality of Tactile corpuscles

Light touch, texture

End bulbs

similar to tactile corpuscles but located in mucous membranes

Location of End bulbs

Mucous membranes

Modality of End bulbs

Similar to tactile corpuscles

Bulbous corpuscles

flat; sense pressure

Location of Bulbous corpuscles

Dermis, subcutaneous tissue, and joint capsules

Modality of Bulbous corpuscles

Heavy continuous touch or pressure; joint movements

Lamellar corpuscles

a bulbous sensory receptor with one or a few dendrites enclosed in onionlike layers of Schwann cells

Location of Lamellar corpuscles

Dermis, joint capsules, periosteum, breasts, genitals, and some viscera

Modality of Lamellar corpuscles

Deep pressure, stretch, tickle, vibration

Muscle spindles

stretch receptors in the muscles that trigger a variety of somatic reflexes; has an elongated capsule, about 4 to 10 mm long, with a fusiform shape.

Location of Muscle spindles

Skeletal muscles near tendon

Modality of Muscle spindles

Tension in muscles (proprioception)

Tendon organs

stretch receptors in tendons that protect against tendon or muscle injury by responding to excessive stretch and inhibiting muscle contration; is about 0.5 mm long and consists of an encapsulated bundle of small, loose collagen fibers and one orm ore nerve fibers that penetrate the capsule.

Locations of Tendon organs

Tendons

Modality of Tendon organs

Tension in tendons (proprioception)

Taste buds

tongue has the most; some in soft palate, pharynx, epiglottis, cheeks and testes; made up of taste cells, supporting cells, and basal cells.

Lingual papillae

Surface projections on tongue

Types of Lingual papillae

Filiform, Folate, Fungiform, Vallate

Filiform papillae

most numerous, tiny spikes, no buds; most abundant papillae on the human tongue.

Folate papillae

ridges on tongue sides, buds in children; parallel ridges on the sides of the tongue about two-thirds of the way back from the tip, adjacent to the molar and premolar teeth.

Fungiform papillae

mushroom shaped bumps, have buds; located mainly on the apex of the tongue.

Vallate papillae

large bumps in a row at the back of the tongue, have buds; arranged in a "V" at the rear of the tongue.

Taste cells

banana-shaped cells; have taste hairs; synapse with sensory nerve

Taste hairs

receptor for taste molecules

Taste pore

Hole on epithelial surface of tongue

Olfactory mucosa

Patch of epithelium on the roof of nasal cavity; contains 10 to 20 million olfactory neurons

Olfactory neurons

have olfactory hairs (cilia) with binding sites for odor molecules; olfactory cell axons make olfactory nerve (CN I)

Olfactory bulbs

swollen tips of olfactory tracts at base of frontal

Outer ear

essentially a funell for conducting airborne vibrations to the tympanic membrane; consist of the Auricle (pinna) and Auditory canal

Auricle (pinna)

the portion of the ear external to the cranium; helix and lobule

Auditory canal

a canal in the temporal bone that conveys sound waves to the eardrum; guard hairs, cerumen

Middle ear

tympanic membrane, tympanic cavity, auditory tube, auditory ossicles, oval window on cochlea, stapedius, tensor tympani

Tympanic membrane

the eardrum

Tympanic cavity

a space only 2 to 3 mm wide between the outer and inner ears; houses the three smallest bones and two smallest skeletal muscles of the body.

Auditory ossicles

the three middle-ear bones; malleus, incus, stapes

malleus

has an elongated handle attached to the inner surface of the tympanic membrane, and a head, which articulates with the incus.

Inner Ear

Bony labyrinth, membranous labyrinth, endolymph, perilymph, vestibule, utricle and saccule, three semicircular canals, cochlea

stapes

the body's smallest bone; has a head that articulates with the incus, an arch, and an elliptical base, giving it an overall shape like a stirrup.

incus

has a roughly triangular body with an articular surface where it meets the malleus; a short limb suspended by a ligament from the wall of the tympanic cavity; and a long limb that articulates with the stapes.

Bony labyrinth

a maze of passages in the petrous part of the temporal bone

Membranous labyrinth

a complex of fluid-filled chambers and fleshy tubes in the bony labyrinth

Endolymph

fluid in membranous labyrinth

Perilymph

fluid between membranous labyrinth and bone

Cochlea

a spiral tube, named for its snail-like shape, contains the organ of hearing

Vestibule

the first part of the bony labyrinth, an ovoid chamber, that contains the utricle and saccule.

Cochlear duct

organ of hearing; contains spiral organ with hair cells: inner hair cells and outer hair cells; stereocilia of hair cells project into tectorial membrane; contains endolymph; hair cells connect with sensory neurons that form the cochlear division of CN VIII

Scala vestibuli

chamber above vestibular membrane; begins near oval window; contains perilymph

Scala tympani

chamber below basilar membrane; ends at round window; contains perilymph

Equilibrium

sense of coordination, balance, orientation; receptors for it constitute the vestibular apparatus which consists of semicircular canals, utricle, and saccule

Saccule

lies nearly vertically on the wall of the saccule

Utricle

lies nearly horizontally on the floor of the utricle

hair cells of the macula (saccule and utricle)

contains kinocilium embedded in the otolithic membrane

three semicircular ducts

filled with endolymph; each of the three ducts are housed in an osseous semicircular canal of the temporal bone; anterior, posterior, and lateral ducts; each have an ampulla with a crista ampullaris

ampulla

a wide or saclike portion of a tubular organ such as a semicircular duct or uterine tube.

Accessory Structures of the Orbit

keep foreign substances out of the eye; eyebrows, eyelids, palpebral fissure, medial/lateral commissures, tarsal gland, eyelashes, conjunctiva

Lacrimal gland

almond shaped, nestled in a shallow fossa of the frontal bone in the superolateral corner of the orbit; tears travel across conjunctiva and cornea

Lacrimal punctum

collects the tears and conveys them through the lacrimal canaliculus into a lacrimal sac; small pore in eyelid

nasolacrimal duct

carries the tears to the inferior meatus of the nasal cavity

Extrinsic Eye Muscles

Superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique