Flashcards in Week 6 Study Cards Deck (229):
What are neural pathways in which reflexes occur over
what are reflexes?
rapid, predictable, involuntary motor responses to stimuli
What are the two classification of reflexes?
autonomic and somatic
What are autonomic reflexes?
are not subject to conscious control
What are somatic reflexes?
all reflexes that stimulate skeletal muscle
What do autonomic reflexes activate?
smooth muscles, cardiac muscle, and the glands of the body and they regulate body functions such as digestion and blood pressure
What are the 5 parts of the reflex arc?
2) sensory neuron
3) integration center
4) motor neuron
What is the receptor?
reacts to a stimulus
What is a sensory neuron
conducts the afferent impulses to the CNS
What is the integration center?
consists of one or more synapses in the CNS
What is the motor neuron?
conducts the efferent impulses from the integration center to an effector
What is the effector?
muscle fibers or glands that respond to the efferent impulses by contracting or secreting a product, respectively
What is monosynaptic?
one synapse reflex arc
What is polysynaptic?
one or more association neuron in the reflex arc pathway
What is synapse?
point of close contact between the neurons or a neuron and an effector cell
What is stretch reflexes?
important postural reflexes that act to maintain posture, balance, and locomotion
How are stretch reflexes produced?
by tapping a tendon which stretches the attached muscle
What does the stretching of the tendon stimulate?
muscle spindles and causes reflex contraction of the stretched muscle to resist further stretching
What is patellar reflex?
when knee ligament is tapped leg jerks forward
What is the achilles reflex?
assesses the first two sacral segments of the spinal cord which causes foot to dorsiflex
What is superficial cord reflexes?
abdominal and plantar reflexes
what are superficial cord reflexes initiated by?
stimulation of receptors in the skin and mucosae
What do the superficial cord reflexes depend upon?
both the brain participation and on the cord level reflex arc
What is plantar reflex?
stimulating the cutaneous receptors in the sole of the foot that cause the toes to flex and move closer together
What is the corneal relex?
reflex mediated through the trigeminal nerve by touching the eye which causes them to blink
What is the pupillary light reflex?
pupil adjusts to light by dilating or constricting
What is consensual reflexes?
one sense on one side and it does it on the other
What is contralateral response?
when a reflex is observed on one side of the body when the other side was stimulated
What is ipsilateral response?
reflex only occurs on the side where stimulation occurs
What are special sense receptors?
large, complex sensory organs (eyes or ears) or localized clusters of receptors (taste buds and olfactory epithelium)
What is the diameter of the adult human eye?
2.5 cm (1 inch)
Anteriorly, what is each eye protected by?
What are the medial and lateral junctions of the upper and lower eyelids referred to as?
medial and lateral commissures (canthi)
What lines the internal surface of the eyelids and continues over the anterior surface of the eyeball to the outer edge of the cornea where it fuses with the corneal epithelium?
conjunctiva mucous membrane
What is the function of the conjunctiva?
secrete mucous which lubricates the eyeball
What is inflammation of the conjunctiva?
What structure projects from the edge of each eyelid?
What lies between the eyelashes?
What is the function of the ciliary glands between the eyelashes?
lubricate the eyeball
What is the inflammation of one of the ciliary glands?
What is located posterior to the eyelashes?
What is the function of the tarsal glands?
secrete an oily substance
What consists of the lacrimal gland and a system of ducts?
What lies superior and lateral to each eye?
What is the function of the lacrimal glands?
continually release a dilute salt solution (tears) onto the anterior surface of the eyeball through small ducts
What do the tears produced first flush into?
What do the tears flush into after the lacrimal canaliculi?
After the lacrimal sac, where do the tears flush?
Where does the nasolacrimal duct empty into?
the nasal cavity
What is the purpose of lacrimal fluid?
to cleanse and protect the eye surface as it moistens and lubricates it
How many eye muscles are attached to the exterior surface of each eyeball
What is the lateral rectus?
moves eye laterally
What is the medial rectus?
moves eye medially
What is the superior rectus?
elevates eye and turns it medially
What is the inferior rectus?
depresses eye and turns it medially
What is the inferior oblique?
elevates eye and turns it laterally
What is the superior oblique?
depresses eye and turns it laterally
What is the outermost part of the eye and is a protective later
What is the fibrous layer composed of?
dense connective tissue
The fibrous layer is composed of what two regions?
sclera and cornea
What is the sclera?
opaque white area is seen anteriorly as the white of the eye and forms the bulk of the fibrous tunic
What is the cornea?
transparent through which light enters the eye
What is myopia?
What is hyperopia?
The eye is not acellular, but rather
what is the middle tunic?
Which layer of the eye is vascular?
What is the posterior part of the middle tunic?
What is the choroid?
a blood rich area and contains a dark pigment to prevent light scattering within the eye
Anteriorly the choroid is modified to form what?
What is attached to the ciliary body?
lens and the iris
What is the round opening in the iris?
pupil through which light passes
What is the iris composed of?
circularly and radially arranged smooth muscle fibers and acts like the diaphragm of a camera to regulate the amount of light entering the eye
In close vision and bright light what muscles in the iris contract?
In distant vision and dim light what contracts in the iris?
What is the innermost layer of the eye?
What is the sensory layer also known as?
What happens to light when it enters the eye?
What is the transparent layer that extends anteriorly only to the ciliary body
neural (nervous tissue) layer
What does the neural layer contain?
rods and cones
What is the function of the rods and cones?
begin the chain of electrical events that pass from the photoreceptors to bipolar cells and then to the ganglion cells
What is the site where the optic nerve leaves the eyeball?
optic disc or blind spot
What is lateral to each blind spot?
macula lutea (yellow spot)
What is the macula lutea?
an area of high cone density
Where is the macula lutea located?
in the middle of the fovea centralis
What is the fovea centralis
a minute pit which contians only cones and is the area of greatest visual acuity
What is light entering the eye focused through?
What is the lens held up in place by?
What is the ciliary zonule?
attached to ciliary body
The lens divides the eye into what two segments?
anterior segment and the posterior segment
What is the anterior segment?
anterior to the lens and contains a clear watery fluid
What is the clear watery fluid?
What is the posterior segment?
behind the lens and is filled with a gel-like substance
What is the gel-like substance?
vitreous humor, vitreous body
Where is the aqueous humor formed?
by the capillaries of the ciliary body
What is the function of aqeuous humor?
maintain the introcular pressure of the eye and provides nutrients for the avascular lens and cornea
Where is aqueous humor reabsorbed?
scleral venous sinus (canal of schlemm)
Where is the scleral venous sinus located?
junction of the sclera and cornea
What is the function of vitreous humor?
reinforces the posterior part of the eyeball and keeps it pushed into its socket
When light passes from one substance to another with a different density its velocity or speed of transmission changes and the rays are bent or what
What causes the light to change its shape?
lens refractive strength by changing shape
What is accommodation?
ability of the eye to focus specifically for close objects
What is the image formed on the retina as a result of the light-bending activity of lens called?
a real image
What is the normal eye also called?
What are some visual problems?
lenses that are too strong or too lazy, structural problems such as an eyeball that is too long or too short, cornea or lens with improper curvatures
What is nearsightedness?
They can see close objects without difficulty but distant objects are blurred or indistinct
What is the correction of nearsightedness?
What happens if the image focuses behind the retina?
What is farsightedness?
don't have problems with distant vission but cant see upclose
What is the correction of farsightedness?
Irregularities in the curvature of the lens and or the cornea lead to a blurred vision called what
What is the condition that results when the elasticity of the lens decreases dramatically with age, resulting in difficulty in focusing for close vision
How can lens elasticity be measured?
near point of accommodation
What are the three cone types?
red, blue, green
What are intrinsic muscles?
controlled by autonomic nervous system are those of the ciliary body and the radial and circular muscles of the iris
What are the extrinsic muscles?
rectus and oblique muscles which are attached to the outside of the eyeball
What is convergence?
medial eye movement which is essential for near vision, both eye aimed toward the same object
the ear is divided into what three main areas?
external ear, middle ear, internal ear
What is the function of outer and middle ear?
sense of hearing only
What is the function of the inner ear?
hearing reception and equilibrium
What is composed of the outer/external ear
auricle or pinna, and external acoustic meatus
What is the pinna?
the skin covered cartilage encircling the auditory canal opening
WHat is the external acoustic meatus?
auditory canal, short narrow chamber carved into the temporal bone
What is the auditory canal lined with??
wax-secreting glands called ceruminous glands
The sound waves enter the canal and hit what?
What is the tympanic membrane?
eardrum that separates the outer ear from the middle ear
What is the middle ear?
small air filled chamber- the typanic cavity within the temporal bone
What is contained in the middle ear?
What are the auditory ossicles?
hammer, anvil, stirrup
What is the function of the auditory ossicles?
transmit vibratory motion of the eardrum to fluids of the inner ear
What do the auditory ossicles transmit the signals to the inner ear through?
What connects the middle ear chamber with the nasopharynx?
pharyngotympanic auditory tube
What is the pharyngotympanic tube function?
opened temporarily to equilize the pressure of the middle ear cavity with the external air pressure
Why is this function important (air pressure releasing)?
eardrum cannot vibrate properly
What is the internal of inner ear?
bony and rather toruous chamber called osseous, bony, labryinth
What is the bony labryinth filled with?
What is floating in the perilymph?
What is the membranous labryinth filled with?
more viscous fluid called endolymph
What are the three subdivisions of the bony labryinth?
cochlea, vestibule, semicircular canals
What shape is the cochlea?
What does the cochlea contain?
receptors for hearing
What is the cochlear membranous labyrinth, a soft wormlike tube about 1 1/2 inches long that winds through turms of the cochlea?
What is the upper chamber of the cochlea?
What does the scala vestibuli abut?
What is the lower chamber?
What does the scala tympani abut?
What does the cochlear duct support?
spiral organ of Corti
What does the spiral organ of Corti contain?
receptors for hearing and nerve endings of the cochlear division of the vestibulochlear nerve
What do the hair cells rest on?
What does the basilar membrane form?
the floor of the cochlear duct
What doe the hair project into?
tectorial membrane that overlies it
What is the roof of the cochlear duct?
What is the equilibrium apparatus of the inner ear?
vestibular and semicircular canal portions of the bony labryinth
What does the vestibular contain?
saclike utricle and the saccule and the semicircular chambers containing membranous semicircular ducts
What are the semicircular ducts?
suspended in perilymph in the bony chambers, filled with endolymph, contain receptor cells that are activated by the disturbance of their cilia
What do the semicircular ducts house?
dynamic equilibrium receptors
What is at the base of each semicircular duct (enlarged area)
What does the ampulla contain?
receptor region called crista ampullaris
What does the crista ampullaris covered in?
tuft of hair cells with a gelatinous cap
What is this gelatinous cap called?
What do the membrane sacs in the vestibule contain?
What are maculae?
static equilibrium receptors that respond to gravitational pull and to linear or straightforwar changes in speed
What is the otolithic membrane?
a gelatinous material containing small grains of calcium carbonate
Where are the otolithic membrane?
over the hair cells in each macula
what is the second major controlling system in the body
what does the endocrine system do?
helps coordinate and integrate the activity of the body's cells
The nervous system uses neurons and electrical signals. What does the endocrine system use?
hormones and their chemical signals
What are hormones?
chemical messengers released into the blood to be transported throughout the body
What are some hormone producing glands?
anterior pituitary, thyroid, adrenals, parathyroid
Where is the pituitary gland situated?
sella turcica of the sphenoid bone
What are the two functional areas of the pituitary gland?
posterior pituitary and the anterior pituitary
What is the posterior pituitary gland composed of
What is the anterior pituitary gland composed of
Why is the posterior pituitary gland not an endocrine gland?
it does not produce the hormones it releases
What does the posterior pituitary gland store?
oxytocin and antidiuretic hormone ADH
What is oxytocin?
stimulates powerful uterine contractions during birth and causes milk ejection in the lactating mother
What is antidiuretic hormone?
kidneys to reabsorb more water from the forming urine, reducing urine output to conserve water
What does the anterior pituitary secrete?
number of hormones
What are tropic hormones
stimulate target organs that are also endocrine glands to secrete their hormones
What are the four tropic hormones of the anterior pituitary?
gonadotropins- follicle-stimlating horomone
thyroid stimulating hormone
What is the function of the gonadotropins hormone?
regulate gamete production and hormonal activity of gonads
What is the function of the adrenocorticotropic hormone?
regulates the endocrine activity of the cortex portion of the adrenal gland
What is the function of the thyroid stimulating hormone
influences the growth and activity of the thyroid gland
What are the 2 other hormones of the anterior pituitary that are not directly involved in regulating other endocrine glands?
What is the function of the growth hormone?
general metabolic hormone, plays an important role in determining body size
What is the function of prolactin?
stimulates breast development and promotes and maintains milk production
What has been considered the master endocrine gland
anterior pituitary because it controls the activity of so many other endocrine glands
What causes the anterior pituitary to release its hormones?
releasing or inhibiting hormones produced by the hypothalamus
What is the general structure of the thyroid?
two lobes joined by a central mass or isthmus
Where is the thyroid located?
throat, inferior to adams apple
What are the two major hormones produced by the thyroid?
thyroid hormone and calcitonin
What is the thyroid hormone function?
two active hormones T4 and T3 and is to control the rate of body metabolism and cellular oxidation
What is the function of calcitonin?
decreases blood calcium levels by stimulating calcium deposit in the bones
What are follicles of the thyroid gland?
spherical sacs containing a pink stained material
What is stored in the follicles of the thyroid gland?
What are the cells seen between the follicles
What is the function of parafollicular cells?
Where are the parathyroid glands located?
embedded in the posterior surface of the thyroid gland
What does the parathyroid gland secrete?
What is the function of the parathyroid hormone?
regulator of calcium phosphate ion homeostasis of the blood, and causes release of calcium from bone matrixs and causes kidneys to reabsorb more calcium
If blood calcium levels fall too low what can occur
What is tetany?
prolonged muscle spasm, can cause respiratory paralysis and may be fatal
Where are the adrenal glands located?
atop the kidneys
Anatomically what does the adrenal medulla develop from?
How are the adrenal medulla stimulated?
nervous system neurons
How do the adrenal medulla respond to stimulation
releasing epinephrine or norepinephrine
What is the function of epinephrine or norepinephrine?
acts with the sympathetic nervous system to produce the fight or flight response to stressors
The adrenal cortex produces three major groups of steroid hormones called what
What are the three hormones produced by adrenal cortex called individually?
What is the function of mineralocorticoids?
aldosterone, which regulates water and electrolyte balance in the extracellular fluids
What is the function of glucocorticoids?
resist long-term stressors
What is the function of gonadocorticoids?
Where is the pancreas located?
partially behind the stomach in the abdomen ands acts as an exocrine and an endocrine gland
What does the pancreas release?
insulin and glucagon
What stimulates the release of insulin?
high blood glucose levels
What is the function of insulin?
decreases blood sugar levels
What is the function of glucagon?
it stimulates the liver to break down its glycogen stores to glucose and to release the glucose to the blood
What stimulates the release of glucagon?
too low of blood glucose levels
What are the roughly circular endocrine portions of the pancreas?
pancreatic islets (islets of Langerhans)
What are alpha cells of the pancreas?
What are the beta cells of the pancreas?
Where are the gonads located?
in the lower pelvic cavity
What are the female gonads?
What do the female gonads produce?
female sex cells, two groups of steroid hormones, estrogen and progesterone
What is the function of estrogen?
development of the secondary sex characteristics of the female at puberty
What is the function of progesterone?
work with estrogen to bring about the menstrual cycle
What are the male gonads?
What do the testes produce?
male sex cells, testosterone