APP Exam 2 Flashcards
What is the biosynthesis for Acetylcholine?
Acetyl-CoA and Choline
What is synthesized to create Serotonin?
Tryptophan—>5-Hydroxytryptophan—–>5-Hydroxytrptamine
For Catecholamines, what is used to create norepinephrine and epinephrine?
Tryosin—–>DOPA (Dihydroxy-phenylalamine——->Dopamine—->Norepinephrine—–>Epinephrine
What are Ligand-gated channels (ionotropic receptors)?
a membrane channel that which is opened when a ligand binds to the receptor. The channel activation is brief
What are Metabotropic receptors?
G-protein coupled receptors. The binding of the ligan initates the production of a second messanger that modulates the ion channels.
What is the difference between ionotropic receptors and metabotropic receptors?
ligand-gated channels: membrane channel that has a ligand present
metabotropic receptors: more complex, has g-coupled receptors
Describe the Glutamate neurotransmitter and the receptors asscociated with it
-is the main excitatory neurotransmitter in the CNS
-has AMPA receptor, NMDA receptor, and Kainate receptor
Describe how NMDA receptors are unique
involved with Glycerine binding, blocked by magensium=removed by depolarization from adjacent AMPA and kainate receptors. The Excitatory Post Synaptic Potential created by these receptors (they work together)
Describe the GABA neurotransmitter and the receptors that are involved.
-major inhibitory mediator in the brain and mediates presynaptic and postsynaptic inhibition
-has three subtypes of receptors (A, B, and C) with A and B being more common in CNS.
-A and C receptors are ionotropic and allow entry of chloride ions into cell-IPSP
-C type found in retina
-B receptors are metabotropic and allow exit of K+, inhibit adenylyl cyclase and allow calcium to come into cell
-A receptors are also made up of 5 subunits
The ________ neurotransmitter is utilized at neuromuscular junction, in autonomic ganglia, in postganglionic parasympathetic nerve-target organ junctions, and some postganglionic sympathetic nerve-target junctions.
Acetylcholine
What structure is Acetylcholine synthesized in?
the nerve terminal, Choline is brought into the cell via a Na+ dependant choline transporter, Choline acetyltransferase is the enzyme for synthesis
Describe the receptors associated with Acetylcholine?
Nicotinic cholinergic receptors: nicotine is agonist, ionotropic receptor, found at neuromuscular junction, found in CNS and autonomic ganglia
Muscarinic cholinergic receptors: metabotropic
Describe the subtype 2 and subtype 3 for Muscarinic Cholinergic receptors
M2=located in the heart and is inhibitory
M3=located on glands and smooth muscle and is excitatory
Which chemical transmitter is present at most sympathetic postganglionic endings?
norepinephrine
Where is norepinephrine and epinephrine synthesized by
the adrenal medulla=blood stream. Most output is epinephrine
What has a greater affinity for norepinephrine?
alpha-1 adrenoreceptors
what has a greater affinity for the Beta receptors?
Epinephrine
What are the functions of the alpha-1 receptors
vasoconstriction
what is the function of B1 receptors?
increased heart rate, vasodilation
what is the function of the Beta 2 receptors?
bronchodilation, lungs; GI, skeletal muscle
Where is the highest concentration of Serotonin present at?
in blood platelets and GI tract. Also is present in brain stem in the midline raphe. This then projects into the hypothalamus, limbic system, neocortex, cerebellum, and spinal cord. Also plays a major role in mood disorders
Define Mechanoreceptors
touch and pressure
Define proprioceptors
info about muscle length and tension (position sense)
Define Thermoreceptors
heat and cold
Define Nociceptors
pain, extreme heat or cold
Define Chemoreceptors
changes in chemical compositions (which include receptors for taste and smell)
Define Photoreceptors
respond to light
What is a dermotome
the area of skin that maps to a specific spinal cord level
Describe the mechanisim associated with a dermatome map
the numbering refers to the spinal cord level that innervates that portion of the skin
What is referred pain?
felt in a somatic structure that is different than the true site of the pain. ex: something is wrong with the heart but you feel it in your shoulder instead
Describe the Doral Column Pathway
function: descriminative touch and position sense
-conscious proprioception-position of body parts
-can discriminate touch
-fine form and texture
-stereognosis: feel something with the hand but you can’t see it with your eyes
-vibration sense
-goes through the entire length of the spine
-afferent pathway- towards the brain
Describe the Spinothalamic Tract
-function: pain and temperature
-from spine to thalamus
-pain sensation
-temperature sensation
-touching something and you can tell what it is
-the pain pathway
-coarse touch
Describe the Spinocerebellar pathways
-carry sensory and proprioception information
-carry unconscious proprioception from the body to cerebellum
-tells the postions of the upper and lower extremities
-from the spine to cerebellum
What are motor pathways?
-control of the muscles by descending pathways
-takes two neurons to get info from cortex to the muscles
-first neuron: upper motor neuron and found in CNS
-second neuron: lower motor neuron and it travels to the muscle in the periphery
What is the Cortiocospinal system (pyramidal system)?
-very clinically important for most muscles
-controls fine movements of the distal musculature
-originates in the frontal lobe of the cortex (precentral gyrus)
-takes two nurons to get the info from the cortex to its motor unit (upper motor neuron and lower motor neuron)
-upper motor neuron will be long and myelinated and go from cortex and stay in CNS and the lower motor neuron (alpha motor neuron); travel to muscle in periphery
What can happen if the corticospinal system is damaged?
paralysis
what is the main function of the extrapyramidal system?
postural control, originates in the brain stem, support role
What is the organization of the CNS?
-Cortex
-diencephalon (deeper conception)-thalamus and hypothalamus
-brain stem-medulla, pons, midbrain
-cerebellum
-spinal cord-cervical, thoracic, lumbar/sacral
What is the stretch reflex?
when a skeletal muscle with an intact nerve supply is stretched=contracts. Also known as the monosynaptic reflex
What is deep and visceral pain?
-there are only C fibers for deep pain (sharp pain)
-poorly localized, can be nauseating, accompanied by sweating and change in blood pressure.
-ex: muscle spasms associated with injuries
Describe the mechanisim of deep pain and how it is carried in the CNS?
afferent fibers from visceral structures reach the CNS via the sympathetic and parasympathetic nerves (ANS), visceral pain can be very severe and the receptors in the walls of hollow organs can be sensitive to distention. When inflamed, relatively minor stimuli can cause severe pain
What is the mechanisim for the stretch reflex?
-stretch muscle—–>activation of muscle spindle—–> legs kick
describe the meissner’s corpuscle
dendrites that are encapsulated in connective tissue and is involved in light touch, changes in texture, or slow vibrations
Describe Merkel’s cells
they are expanded dendritic endings and are used for sustained pressure and touch
Describe the hair follicle receptors
dendrites wrapped around the hair follicle and is sensitive to displacement of the hair
what are the superficial receptors?
meissner’s corpuscle, merkel’s cells, and hair follicle receptors
what are the fine touch for deeper structure receptors?
pacinian corpuscle
what is the pacinian corpuscle?
unmyelinated dendritic endings that are encapsulated by concentric lamellae of connective tissue and is used for deep pressure and fast vibrations
what are ruffini endings?
enlarged dendritic endings with elongated capsule and is used for sustained pressure
______ is mediated by free nerve endings throughout the skin and provide information perceived as crudely localized touch or pressure. They can also carry the sensations of tickle and itching. Carried by the A-alpha and C fibers
course touch (non-discriminative touch)
How can pain sensations be modulated through the gate-controlled mechanisim?
-takes 3 neurons to get one piece of information to the cortex
-first order neuron (with receptor), second order neuron, and third order neuron (ends in the cortex)
-rubbing or shaking an injured area and help with pain
-can involve interneurons in dorsal horn that release endogenous opioids such as enkephalin and dynorphin
what is the role of enkephalin or other opiates?
decreases Ca+ influx=decreases the duration of the action potential. at the synapse, the increase of K+ going out decreases EPSP`
______ is a part of a descending pathway that modulates pain sensations by inhibition of the primary afferent pathway in the dorsal horn and sends fibers to raphe nucleus (seretonin) and to catecholaminergic neurons in brain stem
periaqueductal gray (PAG)
What is nystagmus?
a tremor- like movement of the eyes, with the eyes moving in one direction slowly, then rapidly moving back in the opposite direction. occurs from damage to the vestibular system or to the cerebellum
what is the difference between conductive deafness and sensorineural deafness?
conductive deafness: occurs when transmission of vibrations are prevented in the outer or middle ear (ex: swimmer’s ear)
sensorineural deafness: occurs from damage to the receptors of the cochlear nerve (less common)
Describe the structures of the middle ear
three small bones
-the hammer (malleus)
-anvil (incus)
-stirrup (stapes) MIS
the middle ear is separated from the external ear by the eardrum and connected to the back of your nose and throat by the eustachian tube
Describe the structures associated with the inner ear
bony labyrinth that is filled with perilymph (low K+ levels)
-membraneous labyrinth that is filled with endolymph (K+ rich)
3 components:
-cochlea (for hearing)
-semicircular canals (measures head rotations)
-otolith organs (responds to gravity and head tilts=utricle and saccule)
What structure detects movement of the head
semicircular canals-detects acceleration and deceleration (rotational acceleration), three semicircular canals in ear ear and is filled with endolymph, slushing of the bucket example. utricle (horizontal) and sacule (verticals acceleration)
Determine how physiological nystagmus can be produced
rotational test: spinning the person and observe nystagmus. tilting the head can test the different semicircular canals
caloric test: put warm water and tilt head to put one of the canals in a vertical position. you can only test one side at a time
What are pathological nystagmus examples?
vertigo, dizziness, lightheadedness, and motion sickness. damage to semicircular canals or cerebellum
What systems helps decipher spatial orientation?
- visual system
- vestibular system (equilibrium and balence)
- conscious proprioception and cutaneous exteroreceptors (dorsal column system)
2 can work but 3 would be most favorable
what is the function of the utrcle
detection of head position and detection of horizontal acceleration (and deceleration)`
List the mechanism for sensory inputs that provide information synthesized in the brain stem for the sense of position in space and for controlling eye movement
-vestibular nerve from inner ear that connects with the vestibular nuclei of the brain stem and with the cerebellum
-vestibular nuclei processes the raw data about head movement
-helps control movement of the muscles of the neck and the postural muscles of the body
-sends info up into brain stem to help control eye and head movement
How is a sound wave turned into an action potential?
- sound waves pass through the air filled ear outer ear canal
- sound vibrates the ear drum and the vibration is conveyed across the air-filled middle ear by the ossicles. The ossicles pass vibrations to the oval window, a membrane that seals the opening to the cochlea
- the vibrations reach the fluid filled inner ear where, inside a snail shell shaped cochlea, neurons are activated. the hair cells vibrate and cause depolarization which results in an action potential (influx of calcium)
How is that we can locate where a sound comes from?
the direction from which a sound comes is determined by comparing the loudness of the sound to the two ears, but also by comparing the timing of the sound reaching the two ears, the nuclei in the brain stem helps compare the timing of the sounds
Describe the auditory pathway
passes from the eighth cranial nerve afferent fibers to the dorsal and ventral cochlear nuclei to the inferior colliculi to the thalamic medial geniculate body and then to the auditory cortex.
What pathways are using the information that is detects head and eye movement?
central vestibular pathway
What is the role of the vestibular nuclei for the process of focusing eye on the target
primarily concerned with maintaining the position of the head in space.
Describe the three main layers of the retina
- rods and cones
- inner nuclear layer (interneurons)
- ganglion cell layer (which form the optic nerves)
pupillary light reflex is…
shining a light into one eye causes the pupils in both eyes to constrict and limit the light going into the eyes, used to help test the integrity of the brain stem
Detail the pupillary light reflex mechanism
input from optic nerve goes to the pretectal area of the brainstem, input then goes to the Edinger-Westphal nuclei of the 3rd cranial nerve, causes constriction of the muscles in the pupil
The ratio of rods to cones to ganglion cells in the retina is
105:1
How does light turn into an action potential?
-Na+ channels are open when rods and cones in the dark
-rods and cones release glutamate at a regular rate
-stimulus of light=decrease of cGMP in the cell and closing of the cGMP gated Na+ channels
-hyperpolarizes the cell-reduces release of glutamate
-generates action potential in ganglion cells
What is the difference between the fovea and other structures located in the eye?
the fovea is made up of only cones and has very good visual acuity
What are the main functions of cerebellum?
smooth movement and equilibrium/balence
What are the two major neuron groups found in the cortex of the cerebellum?
- purkinje cells: receives input from the granule cells and fibers coming into cerebellum, send info to the deep cerebellar nuclei
- granule cells: gets input coming directly into the cerebellum and synpases on purkinje cells
How does the cerebellum act on information that was brought on it?
cerebral cortex decides to contract a muscle and sends information down corticospinal tract to the muscle, cortex tells cerebellum what it was doing and receives proprioception information from the spinocerebellar tracts, then compares what was supposed to happen with what actually happened and sends corrections to the cortex
where is the cerebellum located?
located under the cerebrum
List the major differences between the spinocerebellum, vestibulocerebellum, and cerebrocerebellum
spinocerebellum: motor execution—->recieves motor plan from cortex and compares it resulting in smooth movement
vestibulocerebellum: balance and eye movements—->processing info for equilibrium and balence; the info is sent right back
cerebrocerebellum: motor planning—–>interacts with motor cortex planning and programming movements and is more associated with distal limbs
what type of damage is associated with cerebellar lesions
unilateral-affects same side of the body, ataxia: common to all lesions of cerebellum
what type of symptoms can occur with vestibulocerebellar lesions?
truncal ataxia, tendency to fall to side of lesion, dysequilibrium, and nystagmus
what symptoms occur with damage to the spinocerebellum?
ataxia (trunk and axial muscles) and scanning speech
what symptoms can occur with damage to the cerebrocerebellum?
delays in initiating movement, decomposition of movement, limb ataxia, intention tremor (end of movment), dysdiadochokinesia, movement by one joint at a time
What are the major structures of the basal ganglia?
caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra
What are the functions of the basal ganglia?
involved in the planning and programming of movement, influence the motor cortex via the thalamus. helps perform more crude aspects of movement, regulate the gross intentional movement of the body, provide background positioning and moves the limbs and trunk into position from which the more precise movements can occur
Describe Hemiballismus
happens due to damage to the subthalamic nucleus, involuntary movements are sudden, violent swinging motions typically of the arm, abnormal movements are on the side of the body contralateral to the damaged nucleus. lesion on left side, damage to the right side
Describe Huntington’s Disease
a genetically inherited disorder, shows up around 40 years old, first symptoms include absent-mindness, irritability, depression, clumsiness, and sudden falls, choeiform movments increase until the patient is bedridden. Last stages can include severe dementia. is due to loss of caudate nucleus and putamen
Describe Parkinson’s Disease
progressive debailitating disorder, movment disorders can tremor at rest, muscle rigidity akinesia, bradykinesia, disturbed eye movementws, slow and shuffling gate, is caused by a loss of substania nigra cells that produce dopamine
What are the 5 lobules associated with the cerebral cortex and the functions with it?
frontal lobe: motor, executive functions
parietal lobe: somatosensory
temporal lobe: auditory, memory storage
occipital: visual information
limbic: emotions, learning and memory
What is the function of the supplementary motor cortex?
involved in organizing and planning sequence of movements, important for initiation of movement, orientation of the eyes and head, and planning bimanual and sequential movements, engrams are also stored here
What is the main functions of the primary motor cortex (precentral gyrus)
execute movement
What are the language areas of the cortex?
Wernicke’s area and broca’s area
describe the broca’s area
motor programming of speech, only located in the left hemisphere
Describe the Wernicke’s area
associated with language comprehension and is located in the right hemisphere
What are the functions of the prefrontal cortex?
self awareness and executive functions (deciding on a goal, planning on how to accomplish goal, executing the plan, and monitoring the execution of the plan)
What are the differences between the three classifications of white matter
association fibers: connect one area of cortex with another, pipsilaterally
commissural fibers: connect one area of cortex with the similar area, contralaterally
projection fibers: connect cortical areas with subcortical areas (can be ipsi or contra)
What is the difference between the multimodal association cortices and the unimodal association cortices
multimodal association cortices: made up of the prefrontal cortex, parietotemporal association cortex, and the limbic association cortex. recieves input from the unimodal association cortices, very extensive connections
unimodal association cortices: processes visual information
What is the role of the thalamus as a relay station?
some nuclei will be sensory and some will be motor in nature. All information that reaches the the cortex will go through the thalamus, “gateway to the cerebral cortex”
What pathways are associated with the thalamus?
sensory: spinothalamic tract, dorsal column, sensory info from face to mouth via the trigeminal system, and visual info
motor information: from cerebellum and basal ganglia
what is the mechanism for the pathways of the thalamus?
goes to postcentral gyrus (somatosensory gyrus) and go to specific portions of the cortex. motor information goes to frontal lobe
Define an EEG
a recording of the background electrical activity of the brain. can be recorded with electrodes on the scalp. the EEG from scalp is a measure of the total (summation) of dendritic postsynaptic potentials rather than action potentials. Is characterized by high-frequency oscillations in the awake state and low-frequency rhythms during sleep
What is the role of the reticular activating system from the brain stem?
As sensory pathway goes through brain stem, collateral branches, give off collateral branches that can synapse on reticular neurons in brain stem. reticular formation of neurons helps with heart rate, blood pressure, and respiration. Plays an important role in determining the level of arousal for awakeness. Second part forms the RAS system
What is stage 1 of sleep?
theta rhythm (4-7 Hz), low voltage, mixed frequency pattern
what is stage 2 of sleep?
marked by sinusoidal waves called sleep spindles (12-14 Hz)
What is stage 3 of sleep?
delta rhythm (0.5-4 Hz) with high amplitude
What is stage 4 of sleep?
maximum slowing with large waves
What is REM sleep?
rapid, low voltage EEG activity, rapid, roving movements of the eyes occur during this sleep cycle. Activated by secretion of acetylcholine from the pons and inhibited by serotonin
What is the importance of REM sleep?
learning and memory consolidation, does not improve performance
Why is the suprchiasmatic nucleus important in the sleep-wake cycle?
has connections to the brain stem and helps influence the pineal gland
What structures are associated with the Limbic system?
hippocampal formation (hippocampus, denate gyrus, subiculum, parahippocampal gyrus, cingulate gyrus, amygdala, septal area, hypothalamus (mamillary bodies), and anterior nucleus of thalamus
What are the functions of the Limbic system?
learning and memory, emotions important to survival, regulate feeding and drinking, defense and in reproduction, plays a role in helping to regulate hormonal functions
What is the importance of the circuit of papez?
elaborate and express emotions, proceeds in both directions, cortical regions are connected to the similar cortical region on the other hemisphere
Describe the mechanism of the Cortico-Limbic loop
- cingulate gyrus and parahippocampal grus receives the input from the premotor and prefrontal areas as well as the association cortices.
- cingulate gyrus also projects to most cortical areas from where it receives input
Describe the importance for the Hippocampus
plays important role in storage and retrieval of memories, has a “tag” attached so memory can be retrieved, and can be stored in other cortical areas such as temporal lobe
What occurs anatomically with Alzheimer’s disease?
presence of neurofibrillary tangles and neuritic plaques in specific brain regions
What anatomical structures are associated with circuit of papex?
-hippocampal formation
-mamillary body
-anterior nucleus of thalamus
-mamillothalamic tract
-cingulate gyrus
-parahippocampal grus
-cingulum
-entorhinal cortex
What is the mechanism that can occur with organophosphate pesticides and how it can affect the autonomic nervous system?
inhibits acetylcholinesterase at peripheral and central cholinergic synapses and prolongs the effects of acetylcholine. they are then readily absorbed by skin, gut, lung, and conjuctiva. The CNS can show signs of toxicity by having convulsions, seizures, cognitive disturbances, possibly coma
How is the adrenal medulla utilized in the sympathetic division of the autonomic system?
it secretes noepinephrine and epinephrine into the blood stream in response to neutral signals directed via the sympathetic nerve pathways coming via spinal cord
What cell bodies are involved in the preganglionic sympathetic and parasympathetics?
small-diameter, myelinated, relatively slow conducting B fibers
what types of neurons are involved in postganglionic sympathetic and parasympathetic?
unmyelinated C fibers
What neurotransmitter is used for all preganglionic neurons?
Acetylcholine
What is the receptor for acetylcholine on the postganglionic neuron?
nicotinic cholinergic receptor
What chemical transmitter is present at most sympathetic postganglionic endings?
norepinephrine
Where is the sympathetic division located in the ANS?
spinal cord levels T1-L3, intermediolateral cell column of spinal cord
Where is the Parasympathetic division located in the ANS?
brain stem (cranial nerve 3, 7, 9, 10) and sacral portion of the spinal cord
What other areas influence ANS?
limbic system, amygdala, periaqueductal gray
what organs are only innervated by the sympathetic nervous system?
adrenal gland, most blood vessels, hair follicles, sweat glands
what organs are only innervated by only one division of the ANS?
lacrimal gland, ciliary muscle, sublingual salivary glands
what is the difference between the myenteric plexus and the submuscosal plexus?
myentereic plexus: located on the outside. involved in control of GI motility
submucosal plexus: located on the inside, involved in regulating GI blood flow and epithilial cell function
for skeletal muscle arterioles, what is the parasympathetic and sympathetic response and what fibers are involved?
parasympathetic: none
sympathetic: vasodilation (B2), and constriction (alpha-1) also M receptor
for the systemic veins, what is the parasympathetic/sympathetic response and what fibers are associated with it?
parasympathetic: none
sympathetic: vasodilation and constriction (alpha-1, alpha-2, and Beta-2)
for the radial muscles of the iris of the eye, what are the sympathetic/parasympathetic response and the fibers associated with it?
parasympathetic: none
sympathetic: contraction (alpha-1)
for the sphincter muscles of the iris of the eye, what is the parasympathetic/sympathetic response and the neurons involved with it?
parasympathetic: contraction (pupil light reflex)
sympathetic: none
for the SA node of the heart, what is the sympathetic/parasympathetic response and the neurons associated with it?
parasympathetic: decrease heart rate (M2)
sympathetic: increase heart rate (Beta-1)
for the ventricular myocytes of the heart, what is the sympathetic/parasympathetic response and the fibers associated with it?
parasympathetic: none
sympathetic: increase activity (B-1)
for the bronchial smooth muscle, what is the parasympathetic/sympathetic response and the fibers associated with it?
parasympathetic: contraction (M3)
sympathetic: dilation (Beta-2)
for the GI tract with motility and tone, what is the parasympathetic/sympathetic response and the fibers associated with it?
parasympathetic: increase motility and tone
sympathetic: decreases motility and tone
for the GI tract and the control of the sphincters, what is the parasympathetic/sympathetic response and the fibers associated with it?
parasympathetic: relaxation
sympathetic: contraction (alpha-1)
how are hormones secreted from the posterior pituitary gland?
neurons from the hypothalamus sends their axons to posterior pituitary, where action potential causes the release of hormone into the blood stream
how are hormones secreted from the anterior pituitary gland?
neurons from hypothalamus release a hormone into the portal vein system which takes that hormone to the anterior pituitary gland and stimulates cells in the anterior pituitary to release a second hormone into the blood stream
what hormones are released from the posterior pituitary gland?
vasopressin and oxytocin
what hormones are released by the anterior pituitary gland?
growth hormone (GH), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL)
what is the function of the growth hormone released by the anterior pituitary gland?
increase fatty acid levels in blood by breaking down of triglyceride fat and increases blood glucose levels by this mechanisim. also acts on liver to release somatomedin=act on bone and soft tissues to promote growth
what is the function of TSH hormone released by the anterior pituitary gland?
release of thyroid hormone (T3=more common and T4=more potent). primary determinant of the body’s overall metabolic rate
what is the function of the adrenocorticotropic hormone released by the anterior pituitary gland?
acts on adrenal cortex to release cortisol=primary glucocorticoid=plays and important role in carbohydrate, protein, and fat metabolism. helps people resist stress
what is the function of FSH in women that is released by the anterior pituitary gland?
acts on ovaries to stimulate growth and development of the ovarian follicles, promotes secretion of estrogen
what is the function of FSH in males that is released by the anterior pituitary gland?
required for sperm production
what is the function of LH hormone in females that is released by the anterior pituitary gland?
responsible for ovulation, luteinization (postovulatory hormone-secreting corpus luteum in the ovary) and regulation of ovarian secretion of female sex hormones which are estrogen and progesterone
what is the function of LH hormone in males that is released by the anterior pituitary gland?
stimulates the testes to secrete testosterone
what is the function of prolactin hormone that is released by the anterior pituitary gland?
acts on the breasts to enhance breast development and milk production in females and the males function is not known
what hormone is the most abundant in the anterior pituitary gland?
growth hormone
what is the function of IGF-1?
important in skeletal and cartilage growth
what is the function of IGF-II?
important for growth during fetal development
what are factors that impact growth that is associated with the growth hormone?
1.genetic determination
2. adequate diet
3. freedom from chronic disease and stressful environment conditions
4. normal milieu of growth-influencing hormones
what is the most dramatic effect of the growth hormone?
growth of long bones=increased height
where is one place where the growth hormone has an effect on?
epiphyseal plate of a bone
what is the pathway that regulates the growth hormone and the mechanism behind it?
hypothalamus—>growth regulating hormone—> ghrelin in anterior pituitary——>IGF-1 in the liver and other organs—>tissues—–>recycled (feedback loop) to create somatostatin
what is the negative feedback loop?
hormone is released by the target endocrine gland (hormone #3) inhibits the release of the anterior pituitary hormone and the release of its releasing hormone from the hypothalamus
what role does oxytocin play?
stimulates contraction of the uterine smooth muscle during childbirth, promotes ejection of milk from mammary glands, plays a role in parental and pairs bonding, important for trust and empathy, plays a role in anxiety disorders
____ is the only organ that takes up ingested iodine
thyroid gland
what is hypothyroidism and symptoms associated with it?
myxedema, puffy appearance and caused by altered metabolism which infiltrates the skin with complex, water-retaining carbohydrate molecules. can result from failure of thyroid gland, secondary to deficiency of TRH or TSH, or inadequate dietary supply of iodine. symptoms: poor tolerance to cold, excessive weight gain, easily fatiqued, slow speech, poor memory, slow and weak pulse
what hormones regulate thyroid function?
TSH from anterior pituitary gland and is regulated via thyrotropin-releasing hormone (TRH)
what hormones are secreted by the thyroid?
thyroxine (T4), triiodothyronine (T3). T3 is more active than T4. reverse triiodothyronine (RT3)=inactive, calcitonin=calcium-lowering hormone
what are the functions of the thyroid cells?
collect and transport iodide, synthesize thryoglobulin and secrete into colloid, and remove thyroid hormones from the thyroglobulin and secrete them into circulation in the plasma
how is thyroid hormones synthesized?
iodide brought into thyroid cells by Na+/I- symporter (secondary active transport) with sodium being removed from cell by sodium/potassium pump, thyroglobulin is a glycoprotein synthesized in thyroid cell, execreted into colloid, thyroglobulin contains tyrosine residues, iodide is oxidized then bound to tyrosine residues, MIT and DIT are formed and coupled together—>thyroid cells ingest colloid—> t4 and t3 pass into circulation
what protein carriers gold most of T4?
throxine-binding globulin (TBG)
what is essential for enzymatic activity for thyroid hormones?
selenium
what is the mechanisim of action for thyroid hormones?
-readily cross plasma membrane
-t3 binds to thyroid receptors in nuclei with t4 not binding as well
-hormone receptor complex binds to DNA
-increases gene expression the codes for enzymes that regulate cell functions
with the nocireceptors, what does the mechanical receptors do?
strong pressure (sharp object)
with the nocireceptors, what does thermal receptors do?
extreme heat or cold
with the nocireceptors, what does the chemical receptors do?
sensitivity to chemicals; histamine
what A(delta) fibers associated with?
myelinated; first pain, sharp pain
with C fibers, what do they do?
unmyelinated; second pain, slow/dull pain
how do you hear?
-goes from cochlea, then to nuclei, and through the thalamus to the brain, and the way that it comes into the ears is how you can achieve sound localization
for the information that detects movements of the head, how is this information utilized? what pathways are getting this info?
- connections of vestibular nuclei along with muscles of the neck will meet up in the brain stem to help control eye movement; send head movement to the cortex
what is the pigment located in the eye?
rhodopsin: retinal and opsin
primary motor cortex
precentral gyrus, functions to execute movement and can move one finger at a time
primary somatosensory cortex
post central gyrus, sensory info collected from body and head
