Final Flashcards
1
Q
what are the accessory structures of the eye
A
eyebrows
eyelashes
eyelids (palpebrae)
conjunctiva
lacrimal apparatus
2
Q
eyebrows
A
located along supraorbital ridge
aid in nonverbal communication and prevent sweat from dripping into eyes
3
Q
eyelashes
A
extend from margins of eyelids
prevent objects coming into contact with eye
4
Q
eyelids
A
join at medial and lateral palpebral commisures
5
Q
conjunctive
A
transpartent lining of eye and lid surfaces
contains numerous goblet cells to moisten eye, many blood vessels to nourish sclera, abundant nerve endings
does not cover cornea so as not to interfere with light passage
6
Q
ocular conjunctiva
A
covers anterior sclear (white of eye)
7
Q
palpebral conjunctiva
A
covers internal surface of eyelid
8
Q
lacrimal apparatus
A
produces, collects, drains lacrimal fluid (tear film)
lacrimal fluid: water, Na+, antibodies, lysozyme (antibacterial)
lubricates, cleanses and moistens eye, reduces eyelid friction, defends against microbes, oxygenates and nourishes cornea
lacrimal gland: produces fluid and secretes it through ducts
-located in superolateral orbit
blinks (15-20 per/min) wash fluid over eye
9
Q
Lacrimal apparatus flow
A
- lacrimal gland (orbital and palpebral) push lacrimal fluid through ducts on the eyelid covering the eye and traveling to the lacrimal puncta which then flows fluid into lacrimal canaliculi and down the lacrimal sac into the nasolacrimal duct
10
Q
fibrous tunic
A
tough outer layer containing sclera and cornea
11
Q
vascular tunic
A
middle layer containing many vessles that includes the iris, ciliary body, and choroid
12
Q
sclera
A
white of the eye
composed of dense irregular connective tissue
provides eye shape
protects internal components
attachment site for extrinsic eye muscles
13
Q
cornea
A
convex transparent structure at front of eye
limbus: corneal scleral junction
refracts light
14
Q
choroid
A
extensive, posterior region of vascular tunic
many capillaries nourish retina
15
Q
ciliary body
A
ciliary muscles and processes
located anterior to choroid
ciliary muscles: bands of smooth muscle connected to lens
-muscle contraction loosens suspensory ligaments, altering lens shape
ciliary processes: contain capillaries secreting aqueous humor
16
Q
iris
A
gives eye color; most anterior region of uvea
divides the anterior segment into the anterior chamber (between cornea and iris) and posterior chamber (between iris and lens)
pupil is opening in center of iris connecting the two chambers
iris controls pupil diameter
17
Q
pupillary reflex
A
alters pupil size in response to light (increased brightness lead to constriction
18
Q
pupillary constriction
A
bright light
sphincter pupillae contracts (parasympathetic innervation)
pupil shrinks
19
Q
pupillary dialation
A
low light
dialator pupillae contracts (sympathetic innervation)
pupil increases
20
Q
retina
A
contains optic disc, mascula lutea, peripheral retina
21
Q
what are the subtypes of the cells of the neural layer of retina
A
photoreceptor cells
bipolar cells
ganglion cells
22
Q
photoreceptor cells
A
outermost neural layer
contains rods and cones
contain pigments that react to light
23
Q
bipolar cells
A
dendrites receive synaptic input from rods and cones
their axons synapse with dendrites of ganglion cells
24
Q
ganglion cells
A
their axons gather at optic disc and form optic nerve
25
optic disc
contains no photoreceptors (blind spot)
where ganglion axons exit toward brain
26
macula lutea
rounded, yellowish region lateral to optic disc
contains fovea centralis (central pit)
-highest proportion of cones (hardly any rods)
-area of sharpest vision
27
cones
function in high intensity light and in color vision
28
peripheral retina
contains primarily rods
functions most effectively in low light
29
lens
changes shape to focus light on retina
shape determines degree of light refraction
shape is determined by ciliary muscle and suspensory ligaments
30
when viewing objects 20 ft away or more...
muscle relaxes, suspensory ligaments are tense, lens is flattened
31
when viewing objects closer than 20 feet
accommodation
muscle tenses, suspensory ligaments are less tense, lens more spherical
32
vitreous humor (body)
transparent gelatinous fluid in posterior cavity (behind lens)
permanent fluid first produced in embryonic development
helps maintain eye shape
supports retina - keeps it flush against back of eye
33
aqueous humor
transparent watery fluid in anterior cavity (in front of lens)
continuously produced by ciliary processes
nourishes and oxygenates lens and inner cornea
34
aqueous humor secretion
1. aqueous humor is secreted by the ciliary processes into the posterior chamber
2. aqueous humor moves from the posterior chamber through the pupil to the anterior chamber
3. excess aqueous humor is reabsorbed into the scleral venous sinus
35
phototranduction
converting light to electrical signals
performed by photoreceptors
36
rods
more numerous than cones
primarily located within peripheral retina
specialized for dim light, night vision
cannot distinguish color; poor at sharpness of vision
37
cones
less numerous than rods
primarily located in fovea centralis
respond to stimulation by bright light
provide color recognition and sharpness of vision
subdivided into blue, green, and red cones
38
discs within rods and cones contain
photopigment capable of absorbing light
39
dark adaptation
return of sensitivity to low light levels after bright light
rods must regenerate rhodopsin
may take 20-30 minutes to see well
40
light adaptation
process of adjusting from low light to bright conditions
pupils constrict but cones initially overstimulated
takes about 5-10 minutes for full adjustment
41
the ear detects
sound and head movement
signals transmitted via vestibulocochlear nerve (CN VIII)
42
external ear
auricle
external acoustic meatus
tympanic membrane
43
auricle
funnel shaped visible part of ear with elastic cartilage
-protects ear entryway and directs sound waves inward
44
external acoustic (auditory) meatus
ear canal
extends to tympanic membrane
ceruminous glands produce cerumen
-ear wax impedes microorganism growth
45
tympanic membrane
eardrum
delicate funnel-shaped epithelial sheet
partition between external and middle ear
vibrates when sound waves hit it
transmits sound wave energy into middle ear
46
middle ear
auditory tube (eustachian tube)
auditory ossicles (stapes, malleus, incus)
47
eustachian tube / auditory tube
passage extending from middle ear to nasopharynx (upper throat)
equalizes pressure on either side of tympanic membrane
48
auditory ossicles
three tiny bones of middle ear
vibrate along with eardrum so stapes move in and out of oval window initiating pressure waves in inner ear fluid
49
inner ear
cochlea
vestibule
semicircular canals
50
cochlea
houses membranous cochlear duct
51
vestibule
contains two saclike membranous parts: urticle and saccule, interconnected and positioned at right angles
52
semicircular canals
contain membranous semicircular ducts
53
structures of cochlea
bony labyrinth
membranous labyrinth
scala vestibuli
scala tympani
54
bony labyrinth
mazelike spaces in temporal bone
-perilymph: (interstitial fluid) fills most of this space
55
membranous labyrinth
membrane-lined fluid-filled tubes within bony labyrinth
contains receptors for hearing and equilibrium
contains endolyph, similar to intracellular fluid high in k+
56
scala vestibuli
chamber of bony labyrinth adjacent to vestibular membrane
57
scala tympani
chamber of bony labyrinth adjacent to basilar membrane
58
sound wave pathways through the ear
1. sound waves are directed by the auricle into the external acoustic meatus, causing the tympanic membrane to vibrate
2. tympanic membrane vibration moves auditory ossicles (malleus, incus, and stapes); sound waves are amplified
3. the stapes at the oval window generates pressure waves in the perilymph within the scala vestibuli
4. pressure waves cause the vestibular membrane to move, resulting in pressure wave formation in the endolymph within the cohclear duct and displacement of a specific region of the basilar membrane. Hair cells in the spiral organ are distorted initiating nerve signals in the cochlear branch of the vestibulocochlear nerve (CN VIII)
5. remaining pressure waves are transferred to the perilymph within the scala typani and are abosrbed as the round window bulges slightly
59
cochlear hair cell stimulation
-hair cells contain ion channels at their tips and tip link proteins that connect them
-hair cells are bathed in K+ endolymph that is far more positive than the fluid inside the cell
-when basilar membrane moves up, hair cells are pushed into tectorial membrane and their tips are tilted pulling tip links
-tip links pullopen ion channel allowing K+ to diffuse into the hair cell and depolarize it
-hair cell releases more neurotransmitter from its base, excited the sensory neuron, which can fire action potentials
-when basilar membrane moves down, the process quickly reverses
60
pitch
depends on the frequency of the vibrating object
variations in pitch are detectable due to variations in stiffness of basilar membrane from oval window to cochlear apex
61
frequency
rate of vibration in hertz (Hz; cycles per second)
humans can hear 20-20000 Hz
high frequency sounds excite cells in stiff basilar membrane near oval window
low frequency sounds excite cells in flexible basilar membrane near apex
62
loudness
depends on wave amplitude
louder sounds create larger movements of basilar membrane
larger movements cause faster rate of nerve signals and a larger number of stimulate cells
-temporal lobe's auditory cortex interprets this as loudness
63
central nervous system pathways for hearing
1. movement of the basilar membrane produces nerve signals that are propagated along the cochlear nerve to the cochlear nucleus within the medulla oblongata
2a. some secondary neurons relay nerve signals directly to the inferior colliculus of the midbrain
2b. some secondary neurons relay nerve signals to the superior olivary nucleus within the pons, which are then relayed to the inferior colliculus of the midbrain
3. nerve signals are relayed from the inferior colliculus to the thalamus (medial geniculate nucleus)
4. nerve signals are then relayed from the thalamus to the primary auditory cortex of the temporal love of the cerebrum for sound perception
64
equilibrium
awareness and monitoring of head position and movement
information sent to brain to help keep our balance
monitored by vestibular apparatus: urticle, saccule, and semicircular ducts
65
utricle and saccule detect
static equilibrium and liner acceleration
66
semicircular ducts detect
detect angular acceleration
67
static equilibrium
knowing position of your head within vestibule
68
linear acceleration
tells us how were moving (front, left, right)
69
angular acceleration
provides information if we are moving rapidly, spinning, etc
70
macula
receptor for static equilibrium and linear acceleration
loacted in utricle and saccule of vestibule
composed of a layer of hair cells and supporting cells
-hair cells have sterocilia and on kinocilium projecting into gelatinous otolithic membrane
-membrane is covered with otoliths - calcium carbonate crystals
head tilt shift otolithic membrane and bends sterocilia
bending sterocilia toward kinocilium depolarizes hair cells and inreases their transmitter release
opposite reaction occurs if bending is away from kinocilium
71
stereocilia bent toward kinocilium
hair cells depolarize increasing neurotransmitter released
increased nerve signal frequency along vestibular branch of CN VIII
72
stereocilia bent away from kinocilium
hair cells hyperpolarize, inhibiting neurotransmitter release
decreased nerve signal frequency along vestibular branch of CN VIII
73
receptors for angular acceleration in semicircular ducts
base of each semicircular canal has swollen ampulla
- contains crista ampullaris with hair cells and support cells
- stereocilia and kinocilia of hair cells are embedded in gelatinous cupula
when head rotates endolymph pushes against cupula
cupula bends sterocilia and changes hari cell voltage
neurotransmiter release from hair cells changes
firing rate changes on vestibular branch of CN VII
74
endocrine system
composed of DUCTLESS glands that synthesize and secrete hormones
-hormones are released into the blood and transported throughout the body
target cells have the specific receptors for a hormone
-they bind hormone and respond
endocrine and nervous system are the two control systems of the body
75
relationship of hyopthalamus
controls pituitary gland which controls thyroid, adrenal, liver, testes, and ovaries
76
pituitary gland (hypohysis)
lies inferior to hypothalamus
pea sized
connected to hypothalamus by infundibulum (stalk)
partitioned into anterior and posterior pituitary (lobes)
77
posterior pituitary (neurohypohysis)
smaller, neural part of pituitary gland
composed of pars nervosa (love) and infundibulum
hypothalamic neurons project through infundibulum and release hormones in pars nervosa
78
anterior pituitary gland (adenohypohysis)
larger, glandular part of pituitary
partitioned into three areas
-pars distalis, large angterior rounded portion
-pars tuberalis, thin wrapping around infundibulum
-pars intermedia, scant region between the other two areas
79
posterior pituitary is storage and release site for
oxytocin (OT) and antidiuretic hormone (ADH)
80
hormones made in hypothalamus are made by
neurosecretory cells
-packed in secretory vesicles, transported by axonal transport
-released from synaptic knobs into blood when neurons fire ipulses
81
oxytocin
made in paraventricular nucleus
functions: uterine contraction, milk ejection, emotional bonding
82
antidiuretic hormone (vasopressin)
made in supraoptic nucleus
functions: decrease urine production, stimulate thirst, constrict blood vessels
83
flow between hypothalamus and anterior pituitary gland
hypothalamus hormonally stimulates anterior pituitary to release its hormone
-hypothalamus secretes regulatory hormones
-travel via portal blood vessels to pituitary gland
anterior pituitary secretes hormones into general circulation
84
regulatory hormones of the hypothalamus
releasing:
increase secretion of anterior pituitary hormones
thyrotropin-releasing hormone (TRH), prolactin-releasing hormone (PRH), gonadotropin-releasing hormone(GnRH), corticotropin-releasing hormone (CRH), and growth hormone-releasing hormone (GHRH)
inhibiting:
decrease secretion of anterior pituitary hormones
prolactin-inhibiting hormone (PIH)
growth hormone-inhibiting hormone (GHIH)
85
anterior pituitary hormones
tropic hormones and prolactin
thyroid stimulating hormone (TSH)
prolactin (PRL)
adrenocorticotropic hormone (ACTH; corticotropin)
follicle stimulating hormone (FSH)
luteinizing hormone (LH)
growth hormone (GH; somatotropin)
86
thyroid stimulating hormone (TSH)
release triggered by TRH from hypothalamus
causes release of thyroid hormone (TH) from thyroid gland
87
prolactin (PRL)
release triggered by PRH, inhibited by PIH from hypothalamus
causes milk production, mammary gland growth in females
88
adrenocorticotropic hormone (ACTH; corticotropin)
released triggered by CRH from hypothalamus
causes release of corticosteroids by adrenal cortex
89
gonadotropins (follicle-stimulating hormone (FSH) and luteinizing hormone (LH))
release triggered by GnRH from hypothalamus
in female: regulate oocyte development and secretion of estrogen and progesterone
in male: regulate sperm development and secretion of testosterone
90
growth hormone (GH; soatotropin)
release triggered by GHRH, inhibited by CHIH from hypothalamus
causes liver to secrete insulin-like growth factors
91
thyroid gland
sits inferior to thyroid cartilage of larynx, anterior to trachea
left and right lobes connected at midle by narrow isthmus
rish vascularization gives it reddish color
composed of microscopic follicles
-follicular cells
-colloid
-parafollicular cells
92
follicular cells
cuboidal epithelial cells that surround a central lumen
produce and release thyroid hormone (TH)
93
follicle lumen houses
colloid - a viscous, protein-rich fluid
94
parafollicular cells
cells around follicular cells that make calcitonin
hormone that decreases blood calcium levels
95
T3
triiodothyronine
96
T4
thyroxine
97
regulation and action of TH
1. stimulus - hypothalamus is stimulated by one or more of the following: decreased thyroid hormone, other stimuli including cold weather, pregnancy, high altitude, and hypoglycemia
2. receptor - the hypothalamus responds to various stimuli
3. control center- the hypothalamus releases thyrotropin-releasing hormone (TRH) into the hypothalamo-hypophyseal portal system
4. in response to TRH, the anterior pituitary gland releases thyroid stimulating hormone (TSH)
5.TSH stimulates the thyroid gland to release thyroid hormone (TH) into the blood
6. effectors: effectors respond to increased levels of TH in the following ways:
- all cells especially neurons: increased metabolic rate, increased glucose uptake
- liver tissue: increased glycogenolysis and gluconeogenesis, decreased glycogenesis
-adipose connective tissue: increased lipolysis, decreased lipgenesis
- lungs: increased breathing rate, help meet increased O2 demand for aerobic cellular respiration
- heart: increased heart rate, increased force of contraction, help meet increased O2 demand for aerobic cellular respiration
7. net effect - increased metabolic rate occurs, which is supported by increased release of stored nutrient molecules and increased delivery of O2
8. TH levels increase, inhibiting release of TRH and TSH
98
parathyroid glands
small structure on the back of the thyroid gland
between 2-6 of them (usually 4)
contain chief cells and oxyphil cells
99
chief cells
make parathyroid hormone (PTH)
PTH increases blood calcium - liberates it from bone, decreases its loss in urine, activates calcitriol hormone
100
anatomy of the adrenal glands
paired, pyramid-shaped endocrine glands
located on superior surface of each kidney
retroperitoneal, embedded within fat and fascia (limits their motion)
two regions : adrenal medulla and adrenal cortex
101
adrenal medulla
forms inner core of each adrenal gland
red-brown color due to extensive blood vessels
releases epinephrine and norepinephrine with sympathetic stimulation
102
adrenal cortex
synthesizes more than 25 corticosteroids
yellow color due to lipids within cells
three regions producing different steroid hormones: zona glomerulosa, zona fasciculata, and the inner zona reticularis
103
zona glomerulosa
thin outer cortical layer
make mineralocorticoids (hormones that regulate electrolyte levels)
aldosterone: fosters na+ retention and k+ secretion
104
zona fasiculata
larger, middle cortical layer
make glucocorticoids (hormones that regulate blood sugar)
cortisol increases blood sugar
105
zona reticularis
thin, inner cortical layer
makes gonadocorticoids (sex hormones)
androgens are male sex hormones made by adrenals
-converted to estrogen in females
-amount of androgen produced by adrenals is less than amount from testes
106
regulation and action or cortisol hormone
1. stimulus - variables that act on the hypothalamus: negative feedback by cortisol, time of day, stress
2. receptor - hypothalamus responds to various stimuli
3. control center - the hypothalamus releases corticotropin-releasing hormone (CRH) into the hypothalamo-hypophyseal portal system
4. in response to CRH, the anterior pituitary releases adrenocorticotropic hormone (ACTH)
5. ACTH stimulates the adrenal cortex to release glucocorticoids (cortisol) into the blood
6. effectors respond to cortisol
- liver : increased glycogenolysis and gluconeogenesis, decreased glycogenesis
- adipose connective tissue : increased lipolysis, decreased lipogenesis
- all cells : stimulation of protein catabolism (occurs in all cells except hepatocytes), decreased glucose uptake
- high doses of cortisol: increase retention of Na+, H2O, decrease inflammation, suppress the immune system, inhibit connective tissue repair
7. Net Effect - increase of all nutrient molecules in the blood occurs
8. cortisol levels increase inhibiting release of CRH and ACTH
107
cortisol release fluctuates based on time of day
peak levels of cortisol correspond to the late stages of a normal sleep cycle, peaks right before waking in the morning
release is regulated by light and dark cycles detected by the retina as nerve signals are relayed to the hypothalamus
108
cortisol level is increased by stress
both emotional stress (anxiety, anger, fear, etc) and physical stress (fever, trauma, intense exercise) increase the release of cortisol
109
pancreas
sits behind stomach, between duodenum and spleen
pancreas has endocrine and exocrine function
-acini cells generate exocrine secretions for digestion (make up majority of pancreas)
-pancreatic islets (of langerhans) contain clusters of endocrine cells
alpha, beta, delta
110
alpha cells
secrete glucagon
111
beta cells
secrete insulin
112
delta cells
secrete somatostatin
113
regulation and action of insulin
1. Stimulus - increase in blood glucose levels
2. Receptor - beta cells within the pancreas detect an increase in blood glucose levels
3. Control Center - beta cells within pancreas release insulin
4. Insulin stimulates target cells (effectors)
- Liver: increased glycogenesis, decreased glycogenolysis and gluconeogenesis
- Adipose Connective Tissue: increased lipogenesis, decreased lipolysis
- All cells (especially muscle): increased uptake of amino acids, which stimulates protein anabolism
-Most cells: increased uptake of glucose by increasing glucose transport proteins in the plasma membrane
5. Net Effect: decreased blood glucose levels occur (fatty acids and amino acids are also decreased in blood)
114
regulation and action of glucagon
1. Stimulus - decrease in blood glucose levels
2. Receptor - alpha cells within pancreas detect a decrease in blood glucose levels
3. Control Center - alpha cells within pancreas secrete glucagon
4. Glucagon stimulates target cells (effectors):
- liver: increased glycogenolysis and gluconeogenesis, decreased glycogenesis
- adipose connective tissue: increased lipolysis, decreased lipogenesis
5. Net Effect - increased blood glucose and fatty acid levels occur (note- no change in amino acids or proteins)
115
ovaries
estrogen and progesterone
116
estrogen
development of female secondary sexual characteristics
-breast development; widening of pelvis
maturation of eggs
development of uterine lining
117
progesterone
stimulates development of the uterine lining and the formation of the placenta
118
testes
testosterone
development of male secondary sexual characteristics
- facial hair; increased muscle mass; deepening voice
stimulates sperm cell production
119
placenta
human chorionic gonadotropin (hCG)
-prevents degeneration of corpus luteum and thus maintains progesterone secretion
progesterone
stimulates thickening and increased vascularity of uterine lining
estrogen
enlargement of uterus and breasts
