68C Phase I - Exam #4
negative feedback systems
1. hypothalamus regulation (releases hormones); 2. nervous system stimulates glands directly; 3. glands respond directly to changes in internal environment
brainstem
1/4 major portion of brain; connects cerebrum to spinal cord; connects part of the nervous system & regulates certain visceral activities
cerebrum
1/4 major portion of brain; exterior surface called "cerebral cortex"; associated with sensory/motor functions, and memory & reasoning.
cerebellum
1/4 major portion of brain; located in occipital lobe coordinates voluntary muscular movement (inferior peduncles, middle peduncles, superior peduncles)
diencephalon
1/4 major portion of brain; process sensory information
cell body
"soma"; part of a nerve cell that includes cytoplasmic mass & nucleus from which nerve processes extend
mcg = mL
1mcg = 0.001mL
threshold potential
-55mV; the minimum potential that must be reached in order for an action potential to be generated
resting potential
-70mV; potential difference between inside & outside the membrane
retina
Light sensitive layer of the eye; contains photoreceptors(rods & cones)
vagus nerves (X)
MOTOR&SENSORY; SPEECH & SWALLOWING; impulses to heart, smooth muscles & glands in thorax/abdomen
facial nerves (VII)
MOTOR&SENSORY; TASTE receptors on the tongue; conduct impulses to muscles of FACIAL expression
trigeminal nerves (V)
MOTOR&SENSORY; largest; from the pons; ophthalmic (eyes), maxillary (upper MOUTH) & mandibular divisions (lower mouth); chewing
glossopharyngeal nerves (IX)
MOTOR/SENSORY; tonsils, back of tongue and pharynx; gag reflex & swallowing
trochlear nerves (IV)
MOTOR; from midbrain; smallest; conducts motor impulses to MOVE the EYE
abducens nerves (VI)
MOTOR; kinda small; remaining muscles that MOVE the EYE
hypoglossal nerves (XII)
MOTOR; move the TONGUE (speaking, chewing, swallowing)
accessory nerves (XI)
MOTOR; two branches: CRANIAL (soft palate, pharynx, larynx) & SPINAL (neck {shrug, tilt head} & back)
oculomotor nerves (III)
MOTOR; voluntary muscles that raise the eyelid, move EYES & ADJUST the amount of light entering the eyes; focus
nodes of ranvier
Narrow gaps between Schwann cells (myelin sheaths)
medulla oblongata
Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.
optic nerves (II)
SENSORY; associated with VISION
olfactory nerves (I)
SENSORY; sense of SMELL, located in nasal cavity
vestibulocochlear nerves (VIII)
SENSORY; sensory nerves; two branches: vestibular (EQUILIBRIUM) & cochlear (HEARING)
glucagon
Stimulates the liver to break down glycogen, raises blood sugar concentration
pia mater
Very thin and contains many nerves and blood vessels that nourish underlying cells of the brain and spinal cord; contours over these organs
lateral born
a protrusion of gray matter in the thoracic & upper lumber segments
action potential
a rapid change in membrane potential; neuron membrane polarization, return to resting state; forms an impulse along an axon; all or none response
Glasgow Coma Scale (GCS)
a scale used to assess the consciousness of a patient; 1. eye opening, 2. verbal response, 3. motor response (best score is 15, 8 or less is comatose, 3 is lowest; totally unresponsive)
graded potential
a shift in the electrical charge in a tiny area of a neuron
preganglionic fibers of the sympathetic division secrete which neurotransmitters
acetylcholine
paracrine secretions
affecting neighboring cells
cortisol
affects glucose metabolism; influences protein & fat metabolism
thymosin
affects the production of lymphocytes (white blood cells)
middle ear
air-filled space within temporal bone; contains auditory ossicles; auditory tube
association areas
analyze and interpret sensory experiences and oversee memory, reasoning, verbalizing, judgment & emotion; neither primarily sensory or motor
adrenal glands
anterior to kidneys; secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress.
cell membrane surface polarization
arises from unequal distribution of positive & negative ions across the membrane; important in the conduction of impulses in muscle cells & neurons
Decerebrate posturing
arms & legs are extended and the wrists are flexed; problems with midbrain or pons
Decorticate posturing
arms flexed inward and bent in toward the body and the legs are extended; problems with cervical spinal tract or cerebral hemisphere
two major functions of spinal cord
ascending tracts: carry sensory info to the brain; descending tracts: carry motor instructions from brain to muscles/glands
pituitary gland
attached to hypothalamus; regulates growth, reproduction & BP
diabetes mellitus type 1
autoimmune disease; the immune system destroys the beta cells (secrete insulin) of the pancreas
posterior pituitary gland
axons & neuroglia; controlled by nerve responses of the hypothalamus
temporal lobe
below the frontal & parietal lobes; senses for auditory(hearing); "Wernicke's area" (important for understanding written/spoken language)
diabetes mellitus type 2
beta cells produce insulin, but body loses ability to recognize it
barrier that helps prevent chemical fluctuations in the brain & blood
blood brain barrier
sensory (afferent) fibers
bring sensory information to the CNS
external auditory meatus
canal leading inward thru temporal lobe
motor (efferent) fibers
carry impulses from CNS to effectors (muscles/glands)
motor nerves
carry impulses to muscles or glands
ventricle
cavity filled with fluid (brain ventricle = cerebrospinal fluid; heart ventricle = blood)
common features of neurons
cell body (tubular), cytoplasm-filled dendrites, an axon
target cells
cells with specific receptors for a hormone
adrenal medulla
central portion of adrenal gland; secretes epinephrine & norepinephrine
4 major portions of the brain
cerebrum, cerebellum, diencephalon, brainstem
neurotransmitter
chemical that inhibits or stimulates an effector/neuron
middle layer of eye
choroid coat, ciliary body & iris
inner ear
cochlea (hearing), vestibule (static equilibrium), semicircular canals (dynamic equilibrium)
subdural hematoma
collection of blood under the dura mater
external ear
collects & transmits sound waves created by vibrations
iris
colored part of eye
cerebrospinal fluid (CSF)
completely surrounds the brain & spinal cord; occupies the subarachnoid space; maintains a stable ionic concentration; provides a pathway to the blood for wastes
peripheral nervous system (PNS)
composed of nerves that connect the CNS to other body parts; help provide sensory, integrative & motor functions
auditory (eustachian) tube
connects throat with middle ear; maintain equal air pressure on both sides of eardrums
central nervous system (CNS)
consists of brain & spinal cord; help provide sensory, integrative & motor functions
basal metabolic rate (BMR)
consumption at rest in order to maintain life
subarachnoid space
contains cerebrospinal fluid (CSF); between pia mater & arachnoid mater
stress response
controlled by hypothalamus; has immediate "alarm" stage & long term "resistance" stage
Adrenocorticotropic hormone (ACTH)
controls secretions of certain hormones of the adrenal gland
thyroid stimulating hormone (TSH)
controls thyroid gland secretions; regulated by hypothalamus
cAMP
cyclic adenosine monophosphate, second messenger
anterior pituitary gland
dense connective epithelial tissue; controlled by releasing hormones of the hypothalamus
fovea centralis
depression in the center of the retina; produces the sharpest vision
dynamic equilibrium
detect motion of the head & aid in balancing the head and body during sudden movement
channels in cell membranes
determine the distribution of ions; some are always open; other are "gated" or selective with the ions they allow inside
potential difference
difference in electrical charge between two regions
stuporous
difficult to arouse; follow simple commands, speak single words
semicomatose
does not follow commands or speak, withdrawal to painful stimuli
sympathetic division (ANS)
energy-expending, stressful, or emergency situations (fight-or-flight)
polydipsia
excessive thirst
EOM
extraocular movement (of the eyes)
accessory organs of the eye
eyelids, lacrimal apparatus, extrinsic muscles
sense of taste receptors found in
facial, glossopharyngeal, vagus cranial nerves
cochlea
filled with perilymph (fluid); contains organ of hearing (corti)
aqueous humor
fills space between cornea & lens; helps nourish those parts; aids in maintaining the shape of the front of the eye
ependymal cells
form membrane around choroid plexuses; form inner linings that enclose ventricles & central canal
Schwann cells
form myelin sheath in PNS
frontal lobe
forms the anterior portion of each cerebral hemisphere; control of voluntary muscles (motor); concentration, planning, problem solving; speech production
occipital lobe
forms the posterior part of each cerebral hemisphere; sight, visual reception & recognization
astrocytes
found between neurons & blood vessels; provide structural support, join parts by their abundant cellular process; regulate nutrients & ions
unipolar neurons
found in masses of nervous tissue (ganglia); located outside of brain & spinal cord
interneurons
found only in the brain or spinal cord; multipolar; conduct impulses from one part of brain/spinal cord to another part
4 lobes of the brain
frontal, parietal, occipital, temporal, (+/- insula)
synapse
functional connection between two neurons; not in direct physical contact (separated by synaptic cleft)
auricle (pinna) (external ear)
funnel-like; gathers & directs sound waves to the eardrum
sensory receptors
gather information by detecting changes inside/outside the body; monitor external environmental factors; convert info into impulses
endocrine system
glands that secrete hormones into the internal environment
glycosuria
glucose in the urine
basal nuclei
gray matter deep within each cerebral hemisphere; produce dopamine; inhibitor that facilitates voluntary movement
neuronal pools
groups of neurons that make hundreds of synaptic connections with each other & work together to perform a common function
ossicles
help amplify the force of vibrations from eardrum to the oval window
what do endocrine glands & their hormones do?
help regulate the metabolic process
hyperglycemia
high blood sugar
Cushing's syndrome
hypersecretion of adrenal cortical hormones; hyperglycemia; alters carb & fat metabolism
limbic system
hypothalamus, thalamus & basal nuclei; controls emotional experience & expression; can produce fear, anger, pleasure & sorrow
saltatory
impulse conduction where an impulse travels along a myelinated axon & appears to jump from node to node
receptive aphasia
inability to understand spoken or written words (receiving the message)
mixed nerves
include both sensory & motor fibers
parathyroid hormone (PTH)
increases blood Ca2+ concentration & decreases blood phosphate ion concentration; affects bones, kidneys & intestine
thyroid gland
inferior to larynx, anterior to trachea; vascular structure of two large lobes connected by an isthmus
phrenic nerve
innervates the diaphragm (breathing)
steroid hormone receptors
internal receptor that turns on specific genes when it is activated by binding a signal molecule
vitreous humor
jelly-like fluid; between lens & retina; supports the internal parts of the eye & helps maintain shape
patellar reflex
knee jerk reflex
lacrimal apparatus
lacrimal gland; located in the orbit; secretes tears
cones (photoreceptors)
less sensitive to light; detect color; sharp clear images; react quickly to light
thymus
lies in the mediastinum, posterior to sternum, between lungs; secretes thymosin; plays an important part in immunity
myelin
lipid material that forms a sheath-like cover around some axons
pineal gland
located deep between cerebral hemispheres, attached to upper part of thalamus; 3rd ventricle of brain; secrete melatonin
static equilibrium
maintaining stability while the head & body are still
part of brainstem that controls blood pressure & breathing rate
medulla oblongata
hyperpolarization
membrane potential may briefly become overly negative (slow closing K+ channels; sodium/potassium pump can fix it)
synaptic vesicles
membranous sacs that store/release neurotransmitters; found inside axon
neuroglia in the central nervous system
microglial cells, oligodendrocytes, astrocytes, ependymal cells
resting cell membrane
more permeable to potassium ions than sodium ions (potassium diffuses out more than sodium diffuses in)
sensory neurons
mostly unipolar; conduct impulses from body parts into the brain or spinal cord
conjuctiva
mucous membrane that lines the inner surfaces of the eyelid & folds back to cover the anterior surface of the eyeball
brain & spinal cord neurons are
multipolar (one process; each neuron is axon, rest are dendrites)
motor neurons
multipolar; conduct impulses out of the brain or spinal cord to effectors; motor impulses control muscle contraction & secretion of glands
sensory nerves
nerves that conduct impulses to the brain or spinal cord
nuclei
nervous tissue of cell bodies; located INSIDE the CNS
ganglia
nervous tissue of cell bodies; located OUTSIDE the CNS
Addison's disease
occurs when the adrenal glands do not produce enough of the hormones cortisol or aldosterone; dehydration, increased skin pigmentation, hypoglycemia
extrinsic muscles
on the eye's tough outer surface
oligodendrocytes
only in CNS; along axons (nerve fibers); provide insulating layers of myelin within the brain & spinal cord
insulin
opposite of glucagon; regulated by negative feedback; stimulates liver to decrease blood sugar concentration by diffusing glucose across all membranes that have insulin receptors
parasympathetic division (ANS)
ordinary, restful conditions; restores body to resting state following a stressful experience (CHILL)
spiral organ
organ of corti; hearing receptors (hair cells); enables us to hear sounds of different pitch simutaneously
dura mater
outermost layer; tough, white, fibrous connective tissue; contains many blood vessels & nerves; forms the internal periosteum of the skull bones
effectors
outside the nervous system; muscles & glands whose actions are controlled by neurons
hyperthyroidism
overactive thyroid condition; high metabolic rate
somatic nervous system
part of PNS; consists of cranial & spinal nerve fibers; controls skeletal muscle(effectors); voluntary control
autonomic nervous system
part of PNS; motor neurons; functions independently without conscious effort; controls muscles(effectors) that are involuntary; cardiac muscle, smooth muscle & glands; regulates HR, BP, breathing rate, temp; responds to emotional stress
major endocrine glands
pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, reproductive (testes & ovaries), kidneys & thymus
oxytocin (OT)
posterior lobe; Stimulates contraction of the uterus and release of milk from breast; controlled by hypothalamus
antidiuretic hormone (ADH)
posterior lobe; causes kidneys to conserve water; increases blood pressure
parathyroid glands
posterior surface of thyroid gland; 4 small glands on the posterior of the thyroid gland
pancreas
posterior to stomach, behind parietal peritoneum; functions as an exocrine (digestive juice) & endocrine gland(hormones); alpha cells secrete "glucagon", beta cells secrete "insulin"
parietal lobe
posterior to the frontal lobe; skin/touch (cutaneous) sensations, help in understanding speech & choosing words to affect thoughts/feelings;
major contribution to membrane polarization
potassium ions (they pass thru cell membranes much more easily than sodium)
expressive aphasia
problems with speaking or finding words (sending the message)
neuroglia
produces myelin, communicate between cells, maintain ionic environment, nurture differentiation of neurons
luteinizing hormone (LH)
promotes sex hormones; promotes ovulation (releasing egg)
PERRLA
pupils equal, round, reactive to light and accommodation
thalamus
receives all sensory impulses (except smell); pain, touch & temp
parts of a reflex arc
receptor, sensory neuron, interneuron, motor neuron, effector
non-steroid hormones
receptors located on cell membrane; water-soluble; delivers its message by binding to a "second messenger"(cAMP)
steroid hormones
receptors located on nucleus; insoluble in water; soluble in lipids; diffuse into target cells easily
optic disc
region at the back of the eye where nerve fibers exit, becoming part of the optic nerve; blind spot
aldosterone
regulates concentration of mineral electrolytes; stimulate water retention to maintain blood volume & blood pressure
hypothalamus
regulates heart rate, arterial BP, body temp, water/electrolyte balance; hunger & body weight; movements & glandular secretions; sleep/wakefulness; pituitary gland stimulation
midbrain
responsible for reflexes like moving eyes to view something as the head turned; contains auditory reflex to move head to hear sounds
depolarized membrane
resting potential decreases (inside of the membrane becomes less negative compared to outside)
Area stimulated by incoming sensory information
reticular formation
inner layer
retina
repolarization
return of the cell membrane to the resting potential
microglial cells
scattered thru CNS; support neurons & phagocytize (eat) bacteria cells & cellular debris; form scars in area of damage
Follicle-stimulating hormone (FSH)
secreted by the pituitary gland to stimulate maturation of the egg cell; controlled by hypothalamus
autocrine secretions
secretes within itself
axon
send information AWAY in the form of IMPULSES
taste buds
sensory organs of taste; taste/gustatory cell that functions as receptors
types of nerves
sensory/afferent, motor/efferent
pons
separates the midbrain from the medulla oblongata; relay sensory impulses form peripheral nerves to higher brain centers
dendrites
short, highly-branched; RECEIVE input from other neurons
melatonin
sleep-inducing hormone
spinal cord
slender nerve column; consists of 31 segments
choroid plexus
specialized capillaries that secrete cerebrospinal fluid into a brain ventricle
tract associated with pain, touch, temp
spinothalamic tract
types of hormones
steroid and non-steroid
growth hormone (GH)
stimulates cells to enlarge & divide more frequently
Prolactin (PRL)
sustains milk production after birth
neurotransmitters within the CNS
synthesized in the cytoplasm of the synaptic knobs, stored in the synaptic vesicles
placenta
temporary reproductive organ; produces testosterone, estrogen, progesterone & gonadotropin;
main central relay station for incoming impulses
thalamus
sciatic nerve
the largest nerve in the body; originates in the lumbosacral plexus and runs through the pelvis and down the leg
tympanic membrane (eardrum)
the membrane at the end of the ear canal that relays vibrations into the middle ear
adrenal cortex
the outer portion of adrenal glands; aldosterone, cortisol & certain sex hormones (VITAL)
lumbar enlargement
thickening in the lower back; supplies nerves to the lower limbs
cervical enlargement
thickening in the neck portion of the spinal cord; supplies nerves to the upper limbs
ciliary body
thickest part of the middle layer; secretes aqueous humor (clear fluid front of eye)
arachnoid mater
thin, web-like membrane without blood vessels; llies between dura & pia maters
meninges
three protective membranes that surround the brain and spinal cord; dura mater, arachnoid mater, pia mater
thyroid gland hormones
thyroxine (T4), triiodothyronine (T3), calcitonin
Prostaglandins
tissue hormones; produced by liver, kidney, heart, lungs, thymus, pancreas, brains & repro organs (respirations, BP, inflammation, etc)
insula
translating information into appropriate emotional responses
hypothyroidism
underactivity of the thyroid gland; low metabolic rate
comatose
unresponsive to stimuli; possible decerebrate or decorticate posture
choroid coat
vascular, pigmented middle layer; absorbs excess light; keep the inside of the eye dark
Rods (photoreceptors)
very sensitive to light; allow sight in dim light; black & white; slower to react
sclera
white portion of eye; protects the eye;
cornea
window of the eye & helps focus entering light rays; no blood vessels