• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/186

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

186 Cards in this Set

  • Front
  • Back
  • 3rd side (hint)
Ossicles
Malleus
Incus
Stapes
Auditory tube
Also pharyngotympanic tube.
Formerly eustachian tube.
Connects middle ear chamber w/ the nasopharynx.
Equalized pressure of middle ear cavity w/ external air pressure.
Otitis media
Inflammation of the middle ear.
Common among children prone to sore throats.
B/c mucosal membranes of middle ear cavity and nasopharynx are cont. thru the pharyngotypanic tube.
Myringotomy
Lancing of the eardrum.
Cases of otitis media when large amts of pus or fluid accumulate in middle ear cavity.
Relieves pressure.
Tiny tubes sometimes put in during this procedure
Contain perilymph
Scala vestibuli
Scala tympani
Contains endolymph
Cochlear duct (scala media)
Vestibular apparatus
In the vestibule and semicircular canals of the bony labyrinth.
Equilibrium apparatus of the inner ear.
Chambers filled w/ perilymph, in which membranous labyrinth structures are suspended.
Utricle
Contained in the vestibule.

Static equilibrium
Saccule
Contained in the vestibule

Static equilibrium
Vestibule function
Static equilibrium
2 chambers: utricle and saccule
Ossicles function
Form a lever system that amplifies and transmits the vibratory motion of the eardrum to the fluids of the inner ear via the oval window.
3 subdivisions of bony labyrinth
Cochlea
Vestibule
Semicircular canals
Cochlea function
Hearing
Contains sensory receptors for hearing.
Cochlear duct
The cochlear membranous labyrinth.
A wormlike tube
Winds thru the full 2 and 3 quarter turns of the cochlea.
Separates the cochlear cavity into upper and lower chambers: scala vestibuli and scala tympani.
Scala media.
Supports spiral organ of corti
Semicircular canals
Dynamic equilibrium.
Oriented in 3 planes: horizontal, frontal, sagittal.
At the base of each duct is an elarged region: ampulla
W/in each ampulla is a receptor region called a crista ampullaris.
Ampulla
Enlarged region at the base of each semicircular duct.
Communicates w/ utricle of the vestibule.
W/in each ampulla is receptor region called crista ampullaris.
Round window
Membranous area which scala tympani is bound to.
Presbycusis
A type of sensorineural deafness.
Gradual deterioration and atrophy of spiral organ of Corti.
Loss of ability to hear high tones and speech sounds.
Can be caused by excessively loud sounds (damages hair cells).
Acuity test
Person packs one ear w/ cotton and closes eyes.
A ticking clock or watch is held very close to unpacked ear.
Slowly moved away from ear until person signals they cant hear ticking sound.
Sound localization
Person closes both eyes.
Watch held a/b 15 cm from ear and moved to various locations.
Person must locate position of watch by pointing in each instance.
Weber test test for what?
Conduction deafness
Sensorineural (nerve) deafness
Presbycusis
Weber test
Tuning fork is struck and handle is placed medially on partners head.
See if sound is louder in one ear or equally in both.
If sensorineural deafness, tone will not be heard in that ear.
Conduction deafness, sound will be heard more strongly in ear which has hearing loss.
Rinne test test for what?
Comparing bone and air conduction hearing.
Rinne test
Tuning fork is struck and handle placed on partner's mastoid process.
When partner indicates that sound is no longer audible, hold vibrating prongs close to auditory canal.
If can still hear the fork, test result is positive - no hearing loss.
Place next to ear first. When tone cant be heard, place handle on mastoid process.
If partner hears the tone again by bone conduction after hearing by air conduction is lost - some conduction deafness and negative result.
Nystagmus
Involuntary rolling of the eyes in one direction, followed by their rapid movement in the opp. direction.
Balance test and Barany test.
Olfactory epithelium
Organ of smell
Occupies are of about 5cm^2 in roof of nasal cavity.
Taste buds are located primarily on the sides of large round _________?
Circumvallate papillae
Posterior pituitary hormones
Antidiuretic hormone
Oxytocin
Anterior pituitary hormones
GH
Prolactin
TSH
Follicle stimulating hormone
Luteinizing hormone
Adrenocorticotropic hormone
Pineal gland hormones
Melatonin
Thyroid gland hormones
T3
T4
Calcitonin
Parathyroid gland hormones
Parathyroid hormone
Adrenal gland hormones
Aldosterone (mineralocorticoid)
Cortisone (glucocorticoid)
Androgens (gonadocorticoids)
Pancreas hormones
Insulin
Glucagon
Gonad hormones
Female: Estrogen
Progesterone
Male: Testosterone
Special senses
Smell, taste, sight, and hearing
5th special sense=equilibrium
Of all the senses, only_____and______ have fibers that run to both cortical areas and the limbic system.
smell, taste
Olfactory receptors are______neurons.
bipolar
Accessory structures of the eye (adnexa)
eyebrows, eyelids, conjunctiva, lacrimal apparatus, extrinsic eye muscles.
Eyelids (palpebrae)
Protect the eyes anteriorly.
Seperated by the palpebral fissure.
Conjunctiva
A transparent mucous membrane.
Lines the eyelids as the palpebral conjunctiva.
Folds back over the anterior surface of the eyeball as the bulbar conjunctiva (covers only the white of the eye, not cornea).
Lacrimal apparatus
Consists of the lacrimal gland and ducts that drain excess lacrimal secretions into the nasal cavity.
Lacrimal gland releases a dilute salin soln called lacrimal secretion, or tears into the superior part of the conjunctival sac.
Lacrimal secretion (tears) go where?
Blinking spreads tears downward and across the eyeball to the medial commissure.
They then enter the paired lacrimal canaliculi via 2 tiny openings called lacrimal puncta.
Then drain into the lacrimal sac and into the nasolacrimal duct which empties into the nasal cavity at the inferior nasal meatus.
Lacrimal fluid
Contains mucus, antibodies, and lysosyme - an enzyme that destroys bacteria.
Cleanses and protects eye surface as it lubricates.
With eye irritation, enhanced tears wash away or dilute the irritating substance.
Extrinsic eye muscles
There are 6.
Control movement of each eyeball.
Originate from the bony orbit and insert into outer surface of the eyeball.
Lateral rectus, Medial rectus, Superior rectus, Inferior rectus.
Inferiour oblique, Superior oblique.
Superior rectus
Elevates eye (up) and turns it medially.
Cranial Nerve III - oculomotor
Inferior rectus
Depresses eye (down) and turns it medially.
C.N. III - oculomotor
Medial rectus
Moves eye medially (in)
C.N. III - oculomotor
Lateral rectus
Moves eye laterally (out)
C.N. VI - abducens
Superior oblique
Depresses eye and turns it laterally (down, out, medial rotation).
C.N. IV - trochlear
Inferior oblique
Elevates eye and turns it laterally (up, out, lateral rotation)
C.N. III - oculomotor
Strabismus
Congenital weakness of the external eye muscles.
Affected eye rotates medially or laterally.
Fibrous layer of eyeball
Outermost coat of the eye - composed of dense avascular connective tissue.
2 regions - sclera and cornea
Sclera
Forms the posterior portion and the bulk of the fibrous layer.
Seen anteriorly as the "white of the eye".
Protects and shapes the eyeball.
Provides a sturdy anchoring site for the extrinsic eye muscles.
Posteriorly continuous w/ the dura mater of the brain.
Cornea
Clear, avascular
Forms a window that lets light enter the eye.
Major part of the light bending apparatus of the eye.
Bulges anteriorly from its junction w/ the sclera.
Covered by epithelial sheets on both faces.
3 layers of eyeball (tunics)
Fibrous tunic (outer tunic)
Vascular tunic: uvea
Nervous tunic: retina
Vascular layer (tunic)
Forms middle coat of eyeball.
Also called the uvea.
3 regions: choroid, ciliary body, iris
Choroid
Part of vascular layer of eyeball.
Blood vessel rich, dark brown membrane.
B.V. provide nutrition to all eye layers.
Its brown pigment helps absorb light.
Ciliary body
Anteriorly, the choroid becomes the ciliary body.
Thickened ring of tissue that encircles the lens.
Contains ciliary muscles that are important in controlling lens shape.
Posterior surface folds into ciliary processes which contain capillaries that secrete fluid that fills the cavity of the anterior segment of the eyeball.
Ciliary processes make aqueous humor.
Ciliary zonule - suspensory ligaments that hold the lens in its upright position in the eye.
Iris
Part of vascular layer of eyeball.
Visible colored part of the eye.
Most anterior portion of the vascular layer.
Its round central opening, the pupil, allows light to enter the eye.
Pigmented - divides anterior and posterior chamber.
Nervous layer (tunic)
Retina - 2 layered
Outer pigmented layer - absorb light, act as phagocytes to remove dead or damaged photoreceptor cells, store vit. A
Inner neural layer - plays direct role in vision.
Composed of 3 main neurons: photoreceptors, bipolar cells, and ganglion cells.
Optic disc
Where the optic nerve exits the eye.
A weak spot in the fundus (post. wall) - not reinforced by the sclera.
Also called the blind spot b/c lacks photoreceptors.
Don't usually notice these gaps b/c the brain uses a process called filling in.
Rods and cones
Photoreceptors found in the neural retinas
Rods - more numerous, dim light and peripheral vision receptors.
Cones - bright light, provide high acuity color vision.
Macula lutea
An oval region located at the eye's post. pole, lateral to the blind spot of each eye.
"yellow spot"
Contains pit in its center called the fovea centralis.
Mostly cones
Fovea centralis
In this region, retinal structures abutting the vitreous humor are displaced to the sides allowing light to pass almost directl to the photoreceptors rather than thru several retinal layers.
Enhances visual acuity.
Contains only cones
Anything we wish to view critically is focused on the fovea.
Neural retina blood supply
2 sources
Outer 3rd (containing photoreceptors) is supplied by vessels in the choroid.
Inner 2/3 is served by the central artery and central vein of the retina.
Internal chambers and fluids of the eye.
Lens and ciliary zonule divide the eye into 2 segments: ant. and post. segments.
Posterior segment of the eye
Filled w/ clear gel called vitreous humor that binds water.
Vitreous humor transmits light, supports post. surface of the lens, holds neural retina firmly against pigmented layer, contributes to introcular pressure.
Anterior segment of the eye
Partially subdivided by the iris into the ant. chamber and post. chamber.
Ant segment filled w/ aqueous humor.
Aqueous humor
Fills entire ant. segment of eye.
A clear fluid similar in composition to blood plasma.
Forms and drains continually and is in constant motion.
Filters from the cappillaries of the ciliary processes into the post. chamber.
Portion freely diffuses thru the vitreous humor in post. segment, remainder flows into the ant. chamber.
After flowing thru the pupil into the ant. chamber, it drains into the venous blood via the scleral venous sinus (canal of Schlemm).
Both smell and taste use what type of receptor?
Chemoreceptors.
Fila olfactoria
Axons of bipolar neurons.
Pass through cribriform plate and a/b 1000 fila synapse w/ each mitral cell in olfactory bulb.
Olfactory cells
Adapt rapidly.
Sense of smell has a low threshold, esp. to certain odors.
Signal transduction occurs through G protein-coupled receptors.
Olfactory mucosa
Contains sensory fibers from the trigeminal nerve.
Plays a role in initiation of reflexes such as sneezing.
Gustatory sensations
Taste.
Uses chemoreceptors.
Substance must be dissolved before can be detected.
Gustatory sensations (taste) detect what 5 basic sensations?
Salty, sour, sweet, bitter, umami.
Also may have receptors for alkaline, metallic, and water.
Taste buds are located where?
Located on tongue, soft palate, lining of cheeks, pharynx, and larynx.
Taste buds
Each taste bud can have receptors for all primary tastes.
Contains receptor cells, supporting cells and basal cells.
Receptor cells last a/b 3-10 days.
Taste bud secondary receptors
Salty - depolarize directly.
Sour - block potassium channels w/ H+.
All others act through G protein-coupled receptors.
Auricle (pinna)
Part of external ear.
Shell shaped projection surrounding the opening of external acoustic meatus.
Composed of elastic cartilage.
The rim is called the helix.
Directs sound waves into the ext. acoustic meatus.
External acoutic meatus.
Part of external ear.
Short curved tube that extends from the auricle to the eardrum.
Contains ceruminous glands - secretes yellow-brown waxy cerumen (earwax) - provides a sticky trap for for foreign bodies and repels insects.
Tympanic membrane
The eardrum.
Boundary b/t outer and middle ears.
Thin translucent connective tissue membrane.
Shaped like a flattened cone.
Transfers sound E to the tiny bones of the middle ear and sets them into vibration.
Middle ear
Also called tympanic cavity.
Small air-filled mucosa lined cavity of the temporal bone.
Spanned by 3 smallest bones in the body: the auditory ossicles: malleus, incus, and stapes.
Tympanic antrum
Opening into mastoid process.
Pharyngotympanic (auditory) tube
Formerly called the eustachian tube.
Runs downward to link the middle ear cavity w/ the nasopharynx.
Normally flattended or closed, but swallowing or yawning opens it briefly to equalize pressure in the middle ear cavity w/ external air pressure.
Auditory ossicles
3 smallest bones in the body.
Located in tympanic cavity.
Named for their shape.
Malleus, incus, and stapes.
The handle of the malleus is secured to the eardrum.
Tensor tympani
Skeletal muscle associated with auditory ossicles.
Inserts on the malleus.
Tenses the eardrum by pulling it medially.
Stapedius
Skeletal muscle associated w/ auditory ossicles.
Runs from post. wall of middle ear cavity to the stapes.
Checks vibration of the whole ossicle chain and limits movement of the stapes in oval window.
Skeletal muscles associated w/ auditory ossicles.
Tensor tympani and stapedius.
Contract in response to very loud sounds to prevent damage to hearing receptors.
Internal ear
Also called the labyrinth.
Located depp in the temporal bone behind the eye socket.
2 major divisions: bony (osseous) labyrinth and membranous labyrinth.
Bony (osseous) labyrinth
A division of the inner ear.
3 regions: vestibule, cochlea, semicircular canals.
Filled w/ perilymph - fluid continuous w/ cerebrospinal fluid.
Interiour contains endolymph.
These 2 fluids conduct sound vibrations and respond to mechanical forces.
Vestibule
Central cavity of the bony labyrinth.
In its lateral wall is the oval window.
Suspended in its perilymph are 2 membranous sacs: the saccule and utricle.
Static Equilibrium
Semicircular canals
Dynamic equilibrium.
Each canal contains a membranous semicircular duct.
Each duct has an enlarged swelling at one end called the ampulla - houses equilibrium receptor region called crista ampullaris which respont to rotational movements of the head.
Cochlea
Hearing.
Running thru its center is cochlear duct.
Cochlear duct houses the spiral organ (of Corti) - the receptor organ for hearing.
Perilymph
In osseous labyrinth.
Similar to cerebrospinal fluid.
High in Na+, low in K+.
Endolymph
In membranous labyrinth.
Similar to intracellular fluid.
High in K+, low in Na+.
Secreted by stria vascularis.
Modiolus
Cochlea extends from ant. part of the vestibule and coils around a bony pillar called the modiolus.
3 compartments wound around the modiolus - scala vestibuli, scala tympani, scala media (cochlear duct).
Organ of Corti
Hair cells are mechanoreceptors.
Inner hair cells receive 95% of afferent fibers.
Outer hair cells have 1:1 ratio w/ afferent neurons.
Tectorial membrane
Stereocilia and tectorial membrane
Stereocilia touch tectorial membrane and are bent when vibrations pass thru basilar membrane.
Bending causes K+ to enter, depolarization, entrance of Ca++, and release of neurotransmitter.
Direction of bending increases or decreases rate of firing.
Static equilibrium
Maintenance of body posture relative to gravity while the body is still or moving in a straight line.
2 chambers in the vestibule: utricle and saccule.
Dynamic equilibrium
Maintenance of body posture (mainly the head) in response to sudden movements. Tracking a moving object.
Semicircular canals
Neurological connections b/t eyes and semicircular canals - for tracking.
Transmission of sound to internal ear.
Airborne sound entering ext. acoutic meatus strikes the tympanic memb. vibrating it a same frequency.
The motion of tympanic memb. is amplified and transferred to oval window by ossicle lever system.
Pressure waves created by the stapes move thru perilymph fluid in the scala vestibuli.
Sounds w/ great enough frequency are transmitted thru cochler duct into perilymph of scala tympani.
Entire basilar memb. is set into motion.
Organ of Corti transmits this movement to stereocilia of outer hair cells causing them to bend.
Organ of Corti interprets this movement and sends a message thru cochlear nerve onto vestibulocochler nerve (VIII) and onto the brain.
Makes aqueous humor
Ciliary processes.
Accommodation
Focusing the eye to see close objects.
Ciliary muscles.
Myopia
Nearsightedness
Hyperopia
Farsightedness
Emmetropia
Good vision 20/20.
Astigmatism
Light does not focus on a single pt on the retina.
Presbyopia
"Old sight"
Loss of ability to accommodate or see up close.
3 photopigments of color vision
Blue, green, and red.
Most common color blindness
Red-green.
Sex-linked trait carried on X chromosome - males only have one gene for color vision.
Stereopsis
Use both eyes to perceive depth - depth perception.
Nasal fibers cross at the optic chiasm.
Temporal fibers do not cross over.
Each visual cortex, rt and lft, receives info from both eyes so it can compare what each eye sees.
Exocrine glands
Endocrine system.
Secrete their products thru ducts into body cavities or onto body surfaces.
Endocrine glands
Secrete hormones into the interstitial fluid where it enters the blood.
Circulating hormones
Hormones that pass into the blood and act on distant cells.
Have longer lasting effects.
Inactivated by the liver and excreted by the kidneys.
Paracrine secretions
Restricted to the interstitial fluid and affect only nearby cells.
Autocrine secretions
Affect only the secreting cell itself.
Local hormones
Paracrine and autocrine secretions.
Inactivated quickly.
Hormones
Affect virtually all body tissues.
May take hours.
Long lasting effect.
Certain parts of the N.S. stimulate or inhibit the release of hormones.
Hormones may promote or inhibit the generation of nerve impulses.
Some neurotransmitter act as hormones.
Affect only specific tg cells that have receptors that recognize that particular hormone.
Classification of hormones
Steroids.
(Biogenic) amines.
Peptides of proteins.
Eicosanoids.
Nitric oxide acts as local hormone in certain tissues.
Steroids
Lipids formed from cholesterol.
Ex. cortisol, aldosterone, estrogen, testosterone.
Biogenic amines
Simples hormones.
Formed by modifying a.a.
Ex. T3, epinephrine, norepinephrine, histamine.
Eicosanoids
Recently discovered.
Derived from fatty acid called arachidonic acid.
2 types: prostaglandins, leukotrines.
Prostaglandins
An eicosanoid.
Raise b/p, uterine contractions, blood clotting, pain, inflammation
Leukotrines
An eicosanoid.
Affects WBC's.
Mediates inflammation and some allergic rxn's
Most hormones are ______ based.
Amino Acid
With the exception of ______hormone, all a.a. based hormones exert their signaling effects through intracellular __________.
Thyroid.
Second messengers.
Cyclic AMP
A second messenger
Used by neurotransmitters and olfactory receptors.
Cyclic AMP signaling mechanism
Involves the interaction of 3 plasma memb. components to determine intracellular levels of cyclic AMP.
A hormone receptor, a G protein, and an effector enzyme (adenylate cyclase)
Hormone binds receptor - acting as 1st messenger.
Receptor activates G protein.
G protein activates adenylate cyclase.
Adenylate cyclase converts ATP to cyclic AMP - the 2nd messenger.
Cyclic AMP activates protein kinases.
Water-soluble hormone action
Alter cell func. by using a 2nd messenger.
The hormone itself is the 1st mesenger.
Binds w/ a receptor on cell surface activating receptor's active site.
Active site activates a 2nd messenger (cyclic AMP) thru the action of G proteins.
2nd messenger activates other enzymes called protein kinases in the cell.
Second messengers
Act to amplify the effect of hormones b/c they initiate a cascade of rxns w/in the cell.
Action last briefly b/c cAMP is broken down by enzyme phosphodiesterase.
Control of hormone secretion
3 ways.
Pituitary gland releases tropic hormones - stimulates other endocrine glands to secrete their hormones.
Pituitary gland regulated by hypothalamus (hormonal stimuli)
Humoral stimuli - Glands respond directly to changes in the internal enviroment (changing blood levels)
Neural stimuli - N.S. stimulates some glands directly (stimulation of adreanl medulla).
Most often, __________ regulate hormonal secretions.
Negative-feedback systems
Pituitary gland location
Located in the sella turcica of the sphenoid bone.
Connected to hypothalamus by infundibulum.
Divided into anterior (75%) and posteror (25%) glands.
Posterior Pituitary (neurohypophysis)
Made largely of axons of hypothalamic neurons.
Stores antidiuretic hormone (ADH) and oxytocin.
Hormones made in the hypothalamus are stored and released by the post. pituitary gland.
Oxytocin
Hormone of the post. pituitar gland.
Stimulates contraction of the uterus during labor and milk release.
Secretion is controlled by positive feedback.
Plays a role in arousal and orgasm.
Antidiuretic hormone
Inhibits or prevents urine formation.
Prevents wide swings in water balance.
Controlled by osmotic pressure of the blood and blood vol.
Antidiuretic mechanism
Acts on distal convoluted kidney tubules and collecting ducts to incr. their permeablilty to water.
More water is reabsorbed into the body and less urine is formed.
At high conc., causes contriction of arterioles, which raises b/p (vasopressin).
A lack of ADH or receptor causes ________, urine output can = 20L/day.
Diabetes insipidus
Anterior pituitary gland (adenohypophysis)
"master endocrine gland"
Controlled by inhibiting and releasing hormones produced by the hypothalamus.
5 types of cells secrete 7 major hormones.
Tropic hormones
Hormones that regulate the secretory action of other endocrine glands.
All anterior pituitary hormones except for ________ affect their tg cells via a ____________.
Growth hormone
cAMP 2nd messenger system.
Growth Hormone
Produced by somatotrophs.
Hormone of ant. pituitary.
Stimulates cells to incr. in size and reproduce.
Promotes protein synthesis.
Stimulates breakdown of lipids.
Slows breakdown of glu.
Stimulates bone growth directly.
Needs an intermediary, insulin-like growth factor (IGF), to stimulate cartilage.
Hyposecretion of hGH causes_____?
pituitary dwarfism
Hypersecretion of hGH causes_________?
Gigantism before epiphyseal plates close.
Acromegaly after.
Thyroid-Stimulating hormone
Also thyrotropin.
A tropic hormone released by ant. pituitary.
Stimulates the thyroid gland to produce its own hormones: T3 and T4 which control basal metabolic rate.
Prolactin (PRL)
Control thru dopamine (PIH), and inhibitory hormone.
Produced by lactotrophs.
Ant. Pituitary.
Responsible for breast development during pregnancy.
Initiates and maintains milk secretion.
Prolactin in males
Decreases the secretion of LH.
LH necessary for production of male sex hormones.
Prolactin in females
Hypersecretion can cause absence of menstrual cycles in women.
Adrenocorticotropic Hormone (ACTH)
Ant. pituitary.
A peptide that acts on adrenal cortex, causing it to produce larger amts of its hormones (cortisol).
Produced during physiological stress: injury, exercise.
Gonadotropins
Follicle-stimulatin hormone (FSH)
Luteinizing hormone (LH)
FSH and LH
Gonadotropins
Act on gonads (ovaries and testes).
Follicle Stimulating hormone (FSH) in female
Stimulates growth and development of follicle and ovum
Estrogen secretion by the follicle.
FSH in males
Stimulates the seminiferous tubules to grow and produce sperm.
Luteinizing hormone (LH)
Acts w/ FSH to stimulate growth and development of a follicle and ovum.
Ovulating hormone
Sharp rise in LH can cause _______?
Rupture of the follicle and release of the ovum.
LH in males
Called interstitial cell stimulating hormone (ICSH).
Causes interstitial cells of the testes to secrete testosterone.
Thyroid gland location
Anterior neck just below the larynx.
Thyroid gland structure
Made of 2 lobes connected by the isthmus.
Gland is made of follicles that secrete and store the thyroid hormones, extrafollicular cells or C cells.
Follicles are spheres made of a single layer of cuboidal cells and filled w/ colloid.
Thyroid hormone
The body's major metabolic hormone
Acutally 2 amine hormones: thyroxine, or T4 and triiodothyronine, or T3.
T3 and T4
Synthesized from iodine and tyrosine.
Transported in blood bound to special plasma proteins.
Can be released into the capillaries that surround the follicle or can be stored w/in the colloid.
Virtually all the iodine in the body is located where?
Thyroid gland
Hyperthyroidism can be treated how?
Injections of radioactive iodine.
T3 and T4 functions
Control basal metabolic rate.
Growth and development
Thermoregulation
Reactivity of the N.S.
Secretion is controlled by release of TSH.
How is the thyroid gland unique?
Only endocrine gland that stores large quantities of its product - 100 day supply.
Hypersecretion of thyroid gland can cause what?
Grave's disease - person makes abnormal antibodies directed against thyroid folllicle cells, continually stimulate TH release.
Hyposecretion of the thyroid gland can cause what?
Hashimotos disease (autoimmune).
Cretinism in childhood - stunted growth and mental retardation.
Myxedema as adult - edema of face, sensitive to cold, dulled mental func.
Calcitonin
Produced by parafollicular, or C cells, of the thyroid gland.
Lowers blood Ca++ levels.
Lowers phosphorous levels.
Targets the skeleton by inhibiting osteoclast activity and stimulating Ca++ uptake into bone matrix.
Secretion controlled by blood Ca++ levels.
Exophthalmos
Protrusion of the eyeball.
Hyperthyroid activity.
Parathyroid hormone (PTH)
Produced by parathyroid glands - 4 small glands (# can vary) on the post. surface of the thyroid.
Most important hormone controlling the Ca++ levels in blood.
PTH release causes what?
Stimulate osteoclast to digest some bony matrix releasing Ca++ and phosphates to the blood.
Enhances reabsorbtion of Ca++ by the kidneys.
Promotes activation of Vit. D (required for absorbion of Ca++ from food).
Hyposecretion of PTH causes what?
Muscle cramps and seizures.
Hypersecretion of PTH causes what?
osteitis fibrosa cystica - brittle bones.
Adrenal glands location
Located superior to kidneys.
Enclosed in the mass of adipose tissue that surrounds the kidneys.
Adrenal glands structure
Made up of an outer cortex and inner adrenal medulla.
Adrenal cortex
Divided into 3 zones: zona glomerulosa, zona fasciculata, zona reticularis
Each zone produces different steroid hormones.
Zona glomerulosa
Outer layer of adrenal cortex.
Produces mineralocorticoids, mostly aldosterone - hormones that help control balance of minerals and water in the blood.
Zona fasciculata
Middle layer of adrenal cortex.
Produces glucocorticoids, mostly cortisol.
Zona reticularis
Inner layer of adrenal cortex.
Produces androgens - male sex hormones.
Adrenal Medulla
Made up of hormone producing cells called chromaffic cells - surround large B.V.
Secretions are epinephrine and norepinephrine.
Control thru nervous impulses that originate in hypothalamus.
Not essential for life.
Tumor of the adrenal medulla
Pheochromocytomas
Insulin
Beta cell.
Secreted by pancreas.
Decreases blood glucose.
Secretion stimulated by high blood glu. levels.
Type 1 DM
Insulin dependent or juvenile onset diabetes (IDDM).
Due to underproduction of insulin.
Type 2 DM
Noninsulin dependent or adult onset diabetes (NIDDM).
Due to lack of insulin receptors on cell memb.
Oral meds, insulin in some cases.
Pineal gland
"The third eye"
Secretes melatonin
Production controlled by light outside the body.
Regulation of circadian rhythms and promotes sleepiness.
Atrial Natriuretic Peptide (ANP)
Produced by rt atrium of the heart.
The sodium and water losing hormone.
Causes sodium to be excreted into the urine - decreases b/p.