Z332 final Flashcards
Primary sex organs
production of gametes and sex hormones
gonads = testes and ovaries
secondary (accessory) sex organs
transporting and sustaining gametes
hormones
chemical signals produced by endocrine (ductless) glands
long distance in blood and/or lymph
prolonged effects
erectile tissue
corpus spongiosum and corpus cavernosa
scrotal temp
normal body temp 37 C, scrotal temp ~3 lower
necessary for normal spermatogenesis, higher temps –> decreased fertility
dartos and cremaster muscles
control surface area and distance from body
control scrotal temp
pampiniform plexus
countercurrent heat exchange
network of veins and arteries, cool venous blood absorbs heat from arterial blood
ways to control scrotal temp
dartos and cremaster muscles
pampiniform plexus
sweat glands
lack of fat layer
cryptorchidism
undescended testes
typically descend from abdominal cabity 1-2 months before birth
unilateral or bilateral
reduced fertility and increased risk of testicular cancer
seminal vesicle
60-70% vol of semen
bicarbonate (increase pH), prostaglandins, fructose, citrate, coagulating proteins, ions
prostate
25% vol of semen
citrate (increase pH), enzymes break down clot, seminalplasmnin (antibiotic), ions
bulbourethral gland
~1% vol semen
mucous/lubrication, increase pH to neutralize urethra
benign prostatic hyperplasia (BPH)
enlargement of prostate, elderly men, hormone level change with age, risk of bladder infections, kidney damage
prostate cancer
second most common cancer death, androgen dependent, cancerous tissue leaks more PSA (prostate specific antigen) into circulation
spermatogenesis
400 million/day
in seminiferous tubules
diploid spermatogonia stem cells –> haploid sperm
spermatids to mature sperm: elongation, get rid of excess cytoplasm, form tail
mitosis end product
2 daughter cells identical to each other and parent
diploid
produce cells for growth and repair
meiosis end product
4 daughter cells genetically different from each other and parent
haploid
produce cells for reproduction = gametes (sperm and eggs)
spermatogonia
diploid stem cell, divides by mitosis
at puberty…
2 types of daughter cells (A and B) from spermatogonia mitosis
type A daughter cells from spermatogonia
stays at basal lamina
type B daughter cells from spermatogonia
moves toward lumen
becomes primary spermatocyte
primary spermatocyte
goes through meiosis
after meiosis I
2 haploid secondary spermatocytes
after meiosis II
four total haploid spermatids
sperm head
mostly nucleus/DNA
genetic
acrosome
contains hydrolytic enzymes for penetrating egg
midpiece of sperm
lots of mitochondria for energy
metabolic
sperm tail
flagellum
locomotor
leydig cells
secrete testosterone
sertoli cells
sustentocytes supportive roles, nutrients move cells to lumen secrete testicular fluid phagocytosis chemicals to regulate spermatogenesis blood-testis barrier secrete ABP and inhibin (high sperm count = high inhibin)
blood-testes barrier
tight junctions between sertoli cells
maintains environment
excludes toxins
prevents sperm antigens from entering blood
spermtogonia are outside barrier
type B daughter cells pass through junctions
epididymis
where sperm are collected and mature
sperm stored in
ductus deferens
path of sperm
seminiferous tubules, epididymis, ductus deferens, urethra
hypothalamic - pituitary - gonadal axis
hypothalamus –> anterior pituitary –> gonads –> sex hormones
releasing hormones in hypothalamic - pituitary - gonadal axis
secreted by hypothalamic neurons, stimulate pituitary
tropic hormone in hypothalamic - pituitary - gonadal axis
regulated activity of other endocrine organs
GnRH
gonadotropin-releasing hormone
FSH
follicle-stimulating hormone
stimulates sertoli cells to secrete ABP (keep T concentration high around spermatogenic cells)
LH
luteinizing hormone
stimulates leydig cells to secrete T and little estrogen
elevated T triggers spermatogenesis
endocrine control
hypothalamus –> anterior pituitary –> testes –> testosterone secretion and other effects
testosterone
development of male reproductive structures depends on prenatal secretion of male hormones
maintains sex organs (low T = low fertility)
secondary sex characteristics
some converted to estrogen or DHT
clitoris homologous structure
glans penis and corpus cavernosa
labia majora homologous structure
scrotum
labia minora homologous structure
spongy urethra
paraurethral gladn homologous structure
prostate gland
bulb of vestibule homologous structure
corpus spongiosum
grater vestibular gland homologous structure
bulbourethral glands
SRY region
on Y chromosome, master switch
initiates testes development
XO
turners syndrome
female w/o ovaries
XXY
klinefelter’s syndrome
male, usually sterile
YO
males die during development
wolffian duct
future male duct
mullerian duct
future female duct
differences in external genitalia are largely driven by
production of DHT in the dermal layers of urethral folds and labioscrotal swellings
females produce eggs (follicular maturation) and males produce sperm in response to
FSH
endometrium
stratum basalis and stratum functionalis
sf sloughed off during menstruation
menstrual cycle
changes in endometrium in response to varying ovarian hormones
constriction of blood vessels = oxygen deprevation and cells die
sloughing of stratum functionalis
ovulation at day
14
phases of menstrual cycle
menstrual flow : 1-5
proliferative phase: 5-14
ovulation: 14
secretory phase: 14-28
oogenesis
years to complete
lifetime supply of primary oocytes at birth
only ~500 released over life
steps in oogenesis
diploid oogonia (stem cell) divides by mitosis oogonia gradually turn into primary oocytes which start meiosis but arrest early each month 1 primary oocyte continues through meiosis
meiosis of primary oocyte results in
2 unequally sized haploid cells: secondary oocyte and first polar body
secondary oocyte
arrests in metaphase II of meiosis
this is ovulated cell
if no sperm penetration - deteriorates
sperm penetration - completes meiosis resulting in large ovum and small secondary polar body
end result of secondary oocyte meiosis
three small polar bodies and 1 large ovum
primordial follicle surrounds
primary oocyte
proliferation of cells –>
secondary follicle
granulosa cells interact w/ oocyte
late secondary follicle
extr cells, connective tissue layer
vesicular (graafian) follicle
fluid filled cavity (antrum) forms
2 phases of ovarian cycle
follicular and luteal
whole ovarian cycle ~28 days
luteal phase
ruptured follicle collapses after ovulation
remaining granulosa cells enlarge to form corups luteum (endocrine structure)
corpus luteum
no pregnancy: degenerates, stops producing hormones, forms corpus albicans
pregnancy: persists (until placenta is producing hormones) due to hCG secretion from embryo’s chorion
endocrine control (female)
hypothalamus –> anterior pituitary –> ovaries –> estrogen secretion and other effects
LH
triggers ovulation, production of E2
follicles release
E2 and inhibin
corpus luteum releases
E2, P4, inhibin, and relaxin
both LH and FSH stimulate
follicles to secrete estrogen
E2
estrogen
P4
progesterone
from corpus luteum
3 phases in female reproductive cycle
menstrual, preovulatory, postovulatory
menstrual phase
~5 days, stratum functionalis sheds (50-150ml blood, tissue fluid, mucus, cells)
E2 and P4 low: inhibition of GnRH, FSH, and LH
preovulatory phase
variable in length, dominant follicle secreting E2 –> stimulates regeneration of stratum functionalis (endometrium )
cervical mucus thins
ovulation at end of this phase
ovarian cycle=
menstrual phase and preovulatroy phase
ovulation
follicle is almost mature it releases more and more estrogen under influence of LH
high levels of E2 exert positive feedback on Hypo/Ant. Pti. –> LH surge –> ovulation
postovulatory phase
ruptured follicle collapses = corpus luteum (influenced by LH, produces E2, P4, etc)
lack of P4–>
menstruation
E2 and P4 inhibits
FSH
corpus luteum releases P4 –>
slight increase in temp
hCG
human chorionic gonadotropin
home pregnancy kits detect this
4 stages of sexual response cycle
desire
arousal
orgasm (emission, ejaculation) - shortest, intense
resolution
flaccid
at rest vessels constricted
during erotic stimulus….
NO from parasympathetic nerves dilates arteries = increase blood flow
veins cannot drain –> erection
emission and ejaculation from _____reflexes
sympathetic and somatic
Viagra
phosphodiesterase inhibitor increases nitric oxide
emission stage of male orgasm
sympathetic response of moving sperm and semen through ducts
capacitation
sperm becoming motile
undergo capacitation in female reproductive tract after insemination
2-10 hours
acrosome membrane weakens
oxytocin
increases muscular contractions during ejaculation
resolution phase
sympathetic signals constrict artery and reduce blood flow to penis cardiovascular and respiratory responses back to normal refractory period (~10 mins to few hours)
estrogen
development, maintenance of female reproductive structures
secondary sex characteristics
lower blood cholesterol
progesterone
prepare/maintain endometrium for implantation
prepare mammary glands
proliferative phase of menstrual/uterine cycle
functional layer of endometrium is rebuilt
secretory phase of menstrual/uterine cycle
begins immediately after ovulation, enrichment of blood supply and glandular secretion of nutrients prepare endometrium to receive an embryo
corresponds to luteal phase
menstrual phase + proliferative phase =
follicular phase
before ovulation
fertilization in
ampulla of fallopian tube
cervix has grooves and mucous that filter
most well developed sperm for entry (millions in vagina, only thousands make it too uterus)
flowback
in 94% of copulation
less than 1% of sperm might be retained in female reproductive tract
uterine contractions & orgasm
draw sperm and watery midcyclle mucus from cervix to uterus
max sperm retention when
female climax >0-1min post ejaculation
testes size comparisons
gorilla, orangutan, human, chimp
___ fuels competition
testosterone
the presence of an attractive woman….
elevates testosterone and physical risk taking in young men
females initiate sex more in ______ phase
ovulatory
higher average ___ in women who orgasmed
testosterone (orgasm didn’t lead to elevated T)
high T pre and post intercourse
multiple partners associated with _____
higher testosterone
once ovulated, oocyte in viable for
12-24 hours
“obstacle course” sperm must travel through
flowback
harsh environment (low pH, viscosity, immune)
distance
finding the egg (which tube)
fertilization
when sperm and egg combine to form zygote
move toward egg due to chemical cues
not first sperm to reach egg
path of sperm cell during fertilization
corona radiate, zona pellucida (acrosomal reaction), plasma membrane of secondary oocyte, cytoplasm of secondary oocyte
after sperm penetration
oocyte completes meiosis II
sperm and ovum nuclei swell forming pronuclei
pronuclei approach each other and mitotic spindle forms between them
chromosomes intermix, DNA replicates
cleavage
rapid mitotic division
implantation
begin 6-7 days after ovulation
blastocyte implants on endometrium
developing zygote secretes hormones to
maintain corpus luteum
embryo gets nutrients from ____
endometrium until placenta is formed
placenta gets nutrients from
maternal blood by diffusion
active transport - maternal and fetal blood do not mix
maternal effects of pregnancy
increased MR, blood volume, urine production, uterus size, mammary gland production
rising fetal _____ stimulates placental E2
adrenocortical hormones (ex: cortisol)
____ stimulate uterine muscle contraction
oxytocin and prostaglandins
hormone axis
causal chain of events and structures that lead to an outcome
hypothalamus, pituitary, trop hormones, gland, hormone, target cells
intercellular communication
direct - gap junction
endocrine - hormones
synaptic - neurotransmitters
paracrine- extracellular fluid
lipid-soluble hormones
hydrophobic
steroids, thyroid hormones, gases
can pass through membrane
bind to transport protein to travel in blood
water-soluble hormones
hydrophilic
amines, peptides
travel alone in bloodstream
must bind to receptor on cell membrane
all major hormones circulate to…
nearly all the body’s tissues
_____determines whether a hormone acts on a cell
presence or absence of specific receptors (a protein)
receptors can promote or inhibit transcription of different genes
target cell
cell that has a particular hormones receptors
ex: cell with testosterone receptors is a target cell of T
____ often affect gene expression within the cell
lipid soluble hormones
receptors can promote or inhibit transcription of different genes
direct gene activation
steroid hormone diffuses in and binds an intracellular receptor
receptor-hormone complex enters nucleus
receptor-hormone complex binds specific DNA region
binding initiates transcription of the gene to mRNA
the mRNA directs protein synthesis
second-messenger signaling systems
only method water soluble hormones can act; but both lipid and water soluble can use
can have large effects - signal amplification
responsiveness of cell depends on
hormone concentration
abundance of receptors for hormone
strength of binding
influences of other hormones: permissiveness, synergistic, antagonistic
duration of hormone action
usually released in short bursts
increased stimulus = more frequent bursts = increase in concentration
concentration controlled via negative feedback (usually)
most hormones subjected to ____ in target tissues and liver
enzymatic degradation
–> inactivated, exreted
pituitary gland
hypophysis
most important/master endocrine gland b/c it secretes tropic hormones
hypophyseal portal system
tropic hormones of anterior and posterior pituitary enter blood through hypophyseal portal system
artery –> capillary bed
vein –> capillary bed
eventually to heart and whole body
humoral stimulus
hormone release caused by altered levels of certain critical ions or nutrients
neural stimulus
hormone release caused by neural input
hormonal stimulus
hormone release caused by another hormone (a tropic hormone)
protein bound hormones cannot diffuse easily out of capillaries so they must…
dissociate to become biologically active
steroid hormones are synthesized from
cholesterol
in bloodstream, most testosterone is bound to
transport proteins
hypothalamic pituitary adrenal axis (HPA axis)
hypothalamus CRH pituitary ACTH adrenal cortex cortisol (glucocorticoid) target cells
prednisone
synthetic glucocorticoid
cushing’s syndrome
excess glucocorticoids
insomnia, severe fatigue, weak muscles, high bp and blood glucose, thirst, anxiety, depression, fatty hump between shoulders
similar symptoms to chronic stress and/or side effects of synthetic glucocorticoids
hypothalamic pituitary thyroid axis (HPT axis)
hypothalamusactive TRH pituitary TSH thyroid thyroxine (T4) and triiodothyroine (T3) target cells
metabolism
sum total of body’s chemical reactions
production of thyroid hormones
in thyroid follicular cells
iodide oxidized and added to thyroglobulin
results in T1 and T2, combine to form T3 and T4
T4 greater quantity, converted to T3
T3 is most biologically
thyroid hormones bind to
intracellular receptors
only gland that stores large amounts of its hormones
thyroid
thyroid hormones increase
basal metabolic rate and o2 consumption
thyroid hormones regulate
tissue growth and development and reproduction
blood pressure, body temp
grave’s disease
hyperthyroidism
anxiety, breast enlargement in men, difficulty concentrating, double vision, etc.
goiter
enlargement of thyroid gland, due to hyper or hypothyroidism
cretinism
severe hypothyroidism in infants, mental retardation and physical abnormalities
growth hormone axis
hypothalamus GHRH pituitary hGH liver IGF target cells
inhibits release of tropic hormone
inhibiting hormone , GHIH
growth hormone effects
increases rate of protein synthesis
mobilization of fatty acids
decreases glucose utilization
acts synergistically with insulin
acromegaly
excess GH during childhood, growth of cartilage and membranous bone
lack of IGFs in African pygmies results in
smaller stature, but still sexually mature
ADH
antidiuretic hormone, vasopressin
stored and released from posterior pituitary
ADH and oxytocin
ADH produced by
hypothalamus
role of oxytocin
female: childbirth, uterine contractions
male: ejaculation
oxytocin is both…
hormone and neurotransmitter
the love drug- monogamous and promiscuous voles..
as a hormone, oxytocin promote
general trust and cooperation
melatonin
antioxidant
maintains circadian rhythmicity, reflects day length
seasonal changes
pineal gland receives indirect input from SCN
hypothalamus –> reduce GnRH (inhibits reproductive function, many influence time of sexual maturation)
SCN
suprachiasmatic nucleus
biological clock
photoreceptive optic gangial project to SCN from retina, then to pineal gland
seasonal affective disorder
SAD
symptoms appear in fall-winter
depression, anxiety, social withdrawal, weigh gain
alpha cells
from pancreas
glucagon
stimulates glycogen breakdown
beta cells
from pancreas
insulin
stimulates glycogen formation
diabetes mellitus
blood glucose concentration increase
cell use of glucose decreases
increase use of fat and protein
type 1 diabetes
insulin dependent diabetes mellitus
caused by lack of insulin
auto immune disorders, viral infection, hereditary tendency for beta cells to degenerate
type 2 diabetes
non insulin dependent diabetes mellitus
caused by lack of sensitivity of target cells to metabolic effects of insulin = insulin resistance
adrenal gland
steroids: mineralcorticoids (zona glomerulosa), glucocorticoids (zona fasciculate), androgens (zona reticularis)
amine derivatives: epinephrine and norepinephrine
medulla
epinephrine and norepinephrine from chromaffin cells
stimulus: innervation by sympathetic NS
target: everything, enhances sympathetic response
stress response
combined action of ANS and endocrine system
increase heart rate and force
constriction of blood vessels of viscera and skin
dilation of blood vessels in heart, lungs, brain, skeletal muscle
contraction of spleen
glycogen to glucose in liver
sweating
dilation of airways
decrease digestion
water retention
sustained stress can lead to
disease: IBS, ulcers (facilitated not caused), hypertension, anxiety/depression, migraines, suppressed immune function, 2/3 of people overeat
myocardial ischemia
once coronary arteries damaged, they vasoconstrict in response to stress (usually dilate)
chronic stress
distress
disrupts homeostasis
eustress
maintains homeostasis
calcitonin
released from thyroid gland
stimulus: increased Ca
effect: inhibits osteoclasts to decrease Ca levels
parathyroid hormone (PTH)
stimulus: low Ca
effects: stimulates osteoclasts to increase Ca, acts on kidneys to slow low of Ca and Mg in urine, promotes formation of calcitrol (vit D3) to increase absorption of Ca, Mg and Po4 in GI tract
thymus
hormones function in development and maintenance of immune system
thymosins
thymosins
promotes development and maturation of T-lymphocytes (WBC)
menopause
no more primordial follicles left to develop
sex determination
sperm: X or Y
eggs: X or X
Y chromosome contain SRY gene, codes for protein that stimulates AMH (anti-mullerian hormone)
female by default, no Y then feminized
androgen insensitivity syndrome
XY, CAIS (complete, androgen, insensitivity)
external genitalia are female
simplest eye has
photoreceptor, dark pigment, connection to motor structures
cup eye,
detects intensity and direction of light, planaria
compound eye
detailed images, fly
camera eye
detailed images, human
a patch of light sensitive cells could evolve to….
complex eye in ~360,000 generations (few hundred thousand years)
complex eye has evolved more than once
lateral rectus
abducens
superior oblique
trochlear
lacrimal gland
CN VII (facial)
eye blink nerve
facial VII
fibrous tunic
cornea and sclera
avascular connective tissue
conjunctiva
covering sclera, vessels
vascular tunic
choroid, ciliary body, iris
action during accommodation
neural tunic
retina
cornea easily transplanted w/o rejection because
avascular
sclera is continuous with
dura mater on posterior side
glaucoma
eye disorder in which optic nerve suffers damage, permanently damaging vision in affected eye, progressing to complete blindness. associated with increased pressure of fluid in eyes
aqueous humor produced
via filtration at ciliary processes, flows through eye, reabsorbed via scleral venous sinus (canal of schlemm)
DNA identification
vitreous humor can be helpful
zonular fibers of lens
suspensory ligaments
pupil constriction
parasympathetic
sphincter pupillae muscle contracts
pupil dilation
sympathetic
dilator pupil muscle contracts (radial muscle?)
tapetum lucidum
reflective layer within choroid
helps with night vision
not in humans
red eye
due to reflectance of light from camera flash on blood vessels at back of eye
crystallins
in lens, proteins
cataracts
lens becomes cloudy due to clumping of crystallins
accommodation
change in lens shape to focus on near object
increases refractory power
sympathetic activation
CN III oculomotor
(when ciliary muscle relaxes, the suspensory ligaments stretch on lens which flattens it)
when ciliary muscle contracts, less pressure to stretch lens so gets fat - convex = focus closer
refraction
bending of light as it encounters a medium of different density
refracted most when entering cornea
refracted again when entering lens, gets directed to focal point on retina
astigmatism
curvature of cornea or lens varies from one axis to another, images appear distorted
nearsighted
eye ball too long
farsighted
eye ball to short
concave lens
diverges light , focus on farther image
convex lens
converges light, focus on closer image
nearsighted needs ___ lens
concave
farsighted needs
convex lens
lasik surgery
reshaped cornea, affecting focal point of light
2 layers of retina
pigmented layer: prevents light scatter, sores vit A
neural layer: contains photoreceptors, bipolar cells, ganglion cells
detached retina
separation of pigmented and neural layers
vitreous humor seeps in
blindness if not treated - lack of nutrients for photoreceptors
photoreceptors get nutrients from
pigmented layer of retina and from choroid
rod photopigment
rhodopsin (retinal + opsin )
cones photopigment
photopsin (retinal + an opsin)
3 different opsins - one for each color
one type of opsin per cone
cones color
red, green, blue
fibers going to hypothalamus (suprachiasmatic nucleus) help regulate
circadian rhythm
olfactory cilia
mostly nonmotile, increase surface area
olfactory receptors
olfactory sensory neurons, bipolar, lifespan 30-60 days
nasal epithelium innervated by
CN VII facial
odorants…
must be volatile (airborne) and dissolve in fluid coating olfactory epithelium
bind to receptors, G protein pathway activated and cAMP gated channels opens
most active more than one receptor, most receptor can respond to more than one odorant
olfactory transmission…
Na and Ca enter cell
impulse transmission due to Na entry
Ca has role in olfactory adaptation
olfaction pathway
only sensations that go directly to cerebral cortex w/o first synapsing in thalamus
some axons go to limbic system and hypothalamus (emotional memory)
orbitofrontal area: odor identification and discrimination
4 types of papillae
vallate, fungiform, follate, filiform
papillae that have tastebuds
vallate, fungiform, follate
tastes
sweet - sugar and alcohols sour - acids, H+ salty - metal ions, NaCl bitter - alkaloids, caffeine umami- glutamate and aspartate
gustatory epithelial cell
receptors/ taste cells gustatory hairs (microvilli) extend through pore, contact saliva
tastants
chemicas, must dissolve in saliva to inteact with hair and cause transduction
transduction mechanism different for different tastes…
salty: influx of Na depolarized cells
sour: H+ acts intracellular to open cation channels
bitter, sweet, umami: receptor coupled with G protein (gustducin), Ca released, cation channels open
higher amplitude of sound =
louder
each 10dB increase is
10x increase in intensity
threshold of human hearing
0-120 (painful )
short wave
higher frequency, higher pitch
human hearing pitch range
20-20,000
most sensitive between 1500-4000
cerumen
earwax, helps remove debris
auditory tube
pharyngotympanic tube = Eustachian tube
swallowing or yawning opens tube to equalize pressure in middle ear w/ external pressure = ear popping
evolutionary history of ear bones
stapes from 2nd gill arch
malleus, incus, tympanic annulus from 1st gill arch
stapedius muscles and tensor tympani muscles
contract reflexively in response to loud sounds, limits vibration of ossicles and helps prevent damage
bony labyrinth
cavity with 3 regions (vestibule, semicircular canals, cochlea) contains perilymph (continuous with CSF)
membranous labyrinth
sacs and ducts lining body labyrinth, suspended in perilymph contains endolymph (high K concentration)
vestibule
contains utricle and saccule, oval window
semicircular canals
one in each plane, semicircular ducts
cochlea 3 compartments
scala vestibule: continuous with vestibule, abuts oval window
scala meida: cochlear duct
scala tympani: ends at round window
scala tympani and scala vestibule join at
helicotroma (apex of spiral)
high frequency sound displace basilar membrane
near base
medium frequency sounds displace basilar membrane
near the middle
low frequency sounds displace basilar membrane n
near apex
each hair cells has
numerous stereocilia linked together and a single kinocilium
movement of basilar membrane bends stereocilia…
toward kinocilium = opens cation channel, K and Ca flow in, = graded depolarization
away from kinocilium - channels close, repolarization
perception of loudness
more movement of membrane = more frequent APs
conduction deafness
problems with sound conduction through inner ear fluids
blockage, ruptured eardrum, middle ear infection, otosclerosis
sensorineural deafness
damage due to neural structures (hair cells to auditory cortex)
loss of hair cells throughout life or due to prolonged exposure to loud noises or single explosive loudness
degeneration of cochlear nerves, strokes, tumors, etc.
static equilibrium
senses position of body relative to force of gravity (linear acceleration)
directed by maculae in utricle (horizontal movement) and saccule (vertivle)
stereocilia and kinocilium project into otolith membrane
otoliths add weight and inertia
dynamic equilibrium
maintenance of body position in response to rotational acceleration
orientation of semicircular canals,
crista ampullaris
equilibrium organs
vestibular apparatus (vestibule and semicircular canals)
saccule (macula) - vestibule
utricle (macula) - vestibule
ampulla of semicircular ducts/canals (cupula)
vestibular apparatus
sends warning signals, does not automatically correct/compensate for forces of equilibrium
