Integrative Physiology Test 3
PPT/LDT
Also sleep systems in midbrain contributes to NREM-REM transitions during sleep, greater in REM than in NREM
Endogenous pyrogens
Alter sensitivity of warm-sensing neurons in the preoptic area of the hypothalamus--increases body temps set point, mediated by PGE2 synthesis (inhibited by aspirin or Tylenol)
Pathogen
An organism or virus that causes disease (have antigens (proteins)) on surface
Which of the following is FALSE regarding transient receptor potential (TRP) channels 1. They are ion channels that are directly opened by a particular temperature 2. They belong to one of three families 3. Some respond to chemical ligands and their activation is perceived as taste 4. Each has the ability to respond to either hot or cold stimuli 5. They span the plasma membrane six times
Each has the ability to respond to either hot or cold stimuli
Polysomnograph
Electroencephalograph (EEG): measures voltage generated by excitation of the dendrites of the pyramidal cells in the cortex (neural population activity). Electro-oculograph (EOG): Eye movements (detect movements of extraocular muscles) and electromyograph (EMG): Muscle tone: REM muscles are atonic--low electrical activity, no tension
Uncoupling protein 1 (thermogenin)
Enables movement of H+ across mito membrane without using ATP synthase
Sensory information integrated to determine "taste"
Encompasses multiple sensory modalities, gustation (also called taste, olfaction (smell) somatosensation (texture) and thermosensation (trigeminal nerve, V)--coolness (mint) and hotness (capsaicin)
Insensitive regions
Have a large receptive fields and a 2:1 (or more) ratio of 1st to 2nd order neurons (because of convergence)
Both AL/ST and DCML
Have collaterals to the reticular formation which provides alerting stimuli
Complex neural receptors
Have nerve endings enclosed in connective tissue capsules.
Sensitive regions
Have small receptive fields and a 1:1 communication between primary to secondary neurons
Crista ampullaris
Head rotation, head turns and fluid lags behind and pushes the cupula causing stimulation of hair cells
Group A nerve fibers
Heavy myelinated, has 4 subdivisions, alpha, beta, gamma, delta
CD4+ cells
Helper T cells, stimulate other components of the immune response by secreting signaling molecules that activate B cells, cytotoxic cells, inflammatory cells and phagocytes. HIV destroys helper T cells, making people with HIV susceptible to opportunistic infections
Which of the following is best supported by Jo Cameron's case?
Her case lends support for medicinal cannabis in treating chronic pain
Based on the article and the video which of the following is most likely true?
High adenosine levels are associated with increased pain sensitivity
What is sensory coding?
How the brain discriminates between different stimuli
100 degrees Fahrenheit
Hyperthermia (if not cause by fever) sweating and discomfort
95 degrees Fahrenheit
Hypothermia--intense shivering and numbness
Which of the following is TRUE regarding anandamide?
It is an endocannabinoid that is normally made by the brain
REM behavior disorder symptoms
Patients "act out" their dreams. Behavior during REM sleep, and reported dream content, are both often violent
IgM
Pentamer, main antibody of primary response, best at fixing complement, the monomer form of IgM serves as the B cell receptor
Group C
Unmyelinated, thermo (warm) nociceptors--dull, aching pain more diffuse, slow pain, also works with itch, paradoxical cold AL/ST
Pathways for proprioception
Uses A-alpha fibers and is part of the dorsal column/medial lemniscal tract
Ventrolateral Preoptic Area
VLPO is in the hypothalamus and releases GABA and galanin, projects to numerous wake areas including LC, LDT/PPT it is asending and descending, inhibits seceral wake promoting structures.
Thalamus, VLPO, LH
VLPO located in hypothalamus , In mesencephalon
Fab region
Variable region of antibody--provides specificity, specificy of antigen binding determined by VH and VL
2nd order neurons of ventral posterior thalamus (vestibular pathway)
Ventral posterior thalamus and then on to vestibular cortex (awareness of balance)
innate immunity
Very early after exposure to identification (hrs, days), activated by a wide range of pathogens, confers broad protection and the primary function controls spread of infection and direct development of adaptive immunity
Pacinian Corpuscle
Vibration, deep pressure (deeper receptors in dermis)
How is fever initiated
When a local response is not enough--system wide response to infection, activated MPs release IL-1 which triggers hypothalamus in brain to readjust body thermostat to raise body temp. Higher temps defend against bacterial growth, stimulates phagocytosis, speeds up repair of tissues, causes liver and spleen to store iron, reducing blood iron levels--bacteria need large amounts of iron to grow
Vaccines
Work because they give you the intitial exposure, if you have been primed by the vaccine and you encounter the disease for real, you are ready to fight faster AND stronger
What are the various responses initiated by antibodies
1. Activates B cells 2. Acts as opsonins 3. Causes antigen clumping and inactivation of bacterial toxins 4. Activates antibody-dependent cellular activity 5. Triggers mast cell degranulation 6. Activates complement
Mechanisms of action of phagocytes
1. Infectious agent is engulfed by the MP 2. The lysosome and the phagosome fuse together and form the phagolysosome 3. The phagolysosome destroys infectious agents 4. The residue is exocytosed
What three things contribute to how sensory systems can detect the location of a stimulus
1. Size and number of receptive fields: the smaller the receptive fields the greater the acuity. 2. Overlap of receptive fields: provides general information about the location of a stimulus. The brain is able to determine contrast between the neurons 3. Lateral inhibition
How are cytotoxic T cells activated?
1. Tc identifies foreign antigens on MHC I proteins and binds tightly to target cell 2. Tc releases Perforin and granzyme molecules from its granules by exocytosis 3. Perforin molecules insert into the target cell membrane, polymerize and form transmembrane pores similar to those produced by complement activation 4. Granzymes enter the target cell via the pores, once inside, granzymes activate enzymes that trigger apoptosis 5. The Tc detaches and searches for another prey, cell lysis through granule release--perforins, granzymes, activation of apoptosis in target cell-triggered by Fas-Fas ligand binding, activates JUN kinase, caspase 8, aided by granzymes, causes destruction of mitochondria DNA, takes 1-2 days
What three things influence sensory coding?
1. The modality--which type of receptor is activated 2. The intensity of the signal 3. How to detect the location of a stimulus
Hairs bent away from tallest stereocilium
1. Tip links loosen, closing mechanically gated ion channels 2. No cations enter; cell hyperpolarizes 3. Decrease NT release 4. Decrease action potentials in cochlear nerve
Hairs bent toward tallest stereocilium
1. Tip links tighten, opening mechanically gated ion channels 2. More cations enter; cell depolarizes 3. Increase NT release on to cochlear nerve 4. Increase action potentials in cochlear nerve (neurons whose dendrites make up the cochlear nerve).
Steps of response to light
1. cGMP-gated channels close, so cation influx stops. Photoreceptor hyperpolarizes 2. Voltage-gated Ca2+ channels close in synaptic terminals 3. No NT is released 4. Lack of IPSPs in bipolar cell results in depolarization 5. Depolarization opens voltage gated Ca2+ channels; NT is released. 6. EPSPs occur in ganglion cell 7. APs propagate along the optic nerve
In light
11 cis retinal--all trans retinal, retinal absorbs light and dissociates from opsin, leaves behind "bleached opsin" which activates Transducin (G-protein), transducing activates phosphodiesterase which breaks down cGMP. In the presence of light is indicated by a decrease in NT signaling to the bipolar cells--detect changes in light.
Taste buds to gustatory cortex
1st order neurons (that taste receptor cells release NT onto) have cell bodies in the ganglia of CN VII, IX and X ( in head and neck), they synapse onto 2nd order neurons in the nucleus of the solitary tract (in pons and medulla), These neurons ascend and synapse onto 3rd order neurons in the ventral posterior medial (VPM) thalamus, axons of VPM neurons ascend and synapse in gustatory cortex in the TEMPORAL LOBE, vagus nerve (X) innervates taste receptors in taste buds located in the epiglottis
Neural pathway of vestibular system
1st order neurons: vestibular ganglia, 2nd order neurons: vestibular nuclei (pons, medulla), vestibular nuclei project to CN III, IV, VI motor nuclei (eye muscles).
Thermoneutral zone temps
26 and 37 or 78.8 to 98.6
Clock genes
A certain set of genes form a negative feedback loop of transcription-translation that takes about 24 hrs to complete one cycle. These "clock genes" are in most cells of the body, but are required for the SCN for circadian rhythmicity, the SCN synchronizes other cellular clocks throughout the body. If clock genes are disrupted then circadian rhythm is disrupted
Loudness
A function of amplitude (dB) louder sounds have high amplitude waves. Can also be thought of as a measure of intensity. An increase of 10dB correspond to a 10 fold increase in intensity. Normal conversations: 60dB, begins to damage at 80dB and a concert is at 120dB
Pitch
A function of frequency (Hz), high frequency waves gives rise to a high pitched sounds can hear in the range 20-20,000 Hz; hear best between 1000 and 4000 Hz, as we age, we lost hearing in the 250-2050 Hz range
90 degrees Fahrenheit
A medical emergency, delirium, sleepiness, coma
Flip Flop switch for sleep and wake
A model of sleep wake regulated based on mutual inhibition, when one group (sleep vs. wake neurons) is active, it strongly inhibits the other. This results in less inhibition on itself. During wake, wake areas inhibit sleep promoting neurons of the VLPO and PFZ. During sleep VLPO and PFZ inhibit wake promoting areas as well as orexin LH neurosn
Tumor fever
A neoplastic cell causes endogenous pyrogens to be activated, Act towards the tumor by creating a fever to try and destroy it.
Which of the following is FALSE regarding the olfactory system? 1. A pathway through the dorsal olfactory bulb controls olfactory information used for action, whereas a pathway through the ventral olfactory bulb controls olfactory information used for identification 2. Odorants have two pathways for reaching the olfactory epithelium 3. Olfaction is a critical component of detecting flavor 4. Olfactory receptors utilize combinatorial coding, whereas gustatory receptors utilize labeled-line coding 5. The relative size of olfactory structures can be very different across all mammals
A pathway through the dorsal olfactory bulb controls olfactory information used for action, whereas a pathway through the ventral olfactory bulb controls olfactory information used for identification
Shingles
A reinfection of chicken pox virus that had invaded the DRG in the SC. If reactivated, travels through sensory axons to dermatomes associated with infected ganglia
What is a "sensory unit"?
A single afferent neuron with all its receptor endings
What is the Fovea
A small depression in the retina of the eye where visual acuity is the highest, the center of the field of vision is focused in this region. Fovea contains cones only, ration of rods to cones increases as we move away from fovea
Population coding and Frequency coding 1. Allow detection of the intensity of a sensory signal 2. Make up the modality of a stimulus 3. Are used to determine the location of a stimulus 4. Are different types of adaptation used by neural vs. non-neural receptors, respectively 5. Are measures of receptive field overlap and neural convergence, respectively
Allow detection of the intensity of a sensory signal
Pyrogen
A substance, typically produced by a bacterium, which produces fever when introduced or released into the blood, Released and circulate throughout the body, they target the hypothalamus and cause release of PGE2 and raises temp set point
Which of the following regarding adenosine receptors is TRUE?
A1 adenosine receptors are found outside the brain, and have similar effects in cells of other organs
What is complement and its major contribution to innate immunity
About 11 antimicrobial proteins in plasma--'complements' functions of antibodies. They have a number of functions to defend against pathogens. 1. Opsonization 2. Inflammation 3. Cytolysis
IL-2
Activates B cells and cytotoxic T cells
TH1 T cell
Activates MPs to ingest and destroy microbes, also can participate in activation of CTLs. Secretes IFN gamma but also TH1 cells stimulate B cell production of opsonizing antibodies
IL-1
Activates helper T cell to produce IL-2
Tonic receptors
Adapt slowly, transmit signals to the CNS as long as the stimulus persists: biological parameters requiring continuous monitoring such as pain receptors, proprioceptors--muscle spindles
Drowsy or relaxed brain waves
Alpha waves, 8-13 Hz
Which of the following mechanisms sound MOST similar to the way that anandamide may modulate pain sensitivity
Anandamide provides endogenous analgesia similar to enkephalin, weakening pain signals that would be transmitted to higher levels of the brain
Three families of receptors that thermal stimuli activate
Ankyrin--cold (TRPA1) Melastatin--Cool to warm (TRPM8) Vanilloid--mostly hot (TRPV4)
Extreme cold response: shivering
Antagonistic muscle pairs are rhythmically activated, burns energy without productive work--heat, trunk and neck muscles preferentially recruited
Temperature reduction mechanisms
Anterior hypothalamus utilizes sweat glands and vasodilation. Uses cholinergic receptors of the SNS to release Ach
Two chambers
Anterior saccule and posterior utricle and is responsible for static equilibrium and linear acceleration
AL/ST
Anterolateral (spinothalamic) tract senses crude touch/pressure, pain and temperature, all free nerve endings and 1st order neuron enters dorsal horn and synapses there 1. receptor--DRG (1st order)--SC (2nd order and decussates)--VPL (3rd order)--SS cortex 2. Receptor--DRG (1st order)--SC (2nd order and decussates at medial thalamus)--Medial thalamus (3rd order)--limbic system 2nd pathway underlies emotional and autonomic components of pain
Sweating
Apocrine--through to function as scent glands Eccrine: dominant role in thermoregulation. Controlled by neurons in the anterior hypothalamus, cools skin through evaporative heat loss
What happens when a B cell binds to an antigen?
Are activated when it encounters its matching antigen (by binding to antibodies on the B cell surface). The B cell engulfs the antigen and digests it. B cells then display the antigen on unique MHC II molecules. The combination of antigen and MHC attracts a helper T cell. Cytokines secreted by the helper T cell help the B cell mature and multiply (clonal expansion). Released into the blood, antibodies lock onto matching antigens. The antigen/antibody complexes are cleared by the complement cascade.
Visceral and somatic receptors
Are both mechanoreceptors
Special senses receptors
Are non neural receptors, release NTs onto sensory neurons, initiating an AP
Non neural sensory receptors
Are not neurons, but cells that communicate with neurons. Release NTs onto the sensory neurons which causes an AP, receptor potentials
B lymphocytes
Are responsible for humoral immunity, Plasma B cells and memory cells
T lyphocytes
Are responsible for the development of cellular immunity, CD8, CD4 and Suppressor T cells
Inner hair cells
Are the sensory receptors--detect vibrations coming from the waves--transmit through afferent axons that make up the auditory nerves. One row of inner hairs
Rod photoreceptors... 1. Come in 3 different types 2. Are 1st order neurons of the visual system 3. Are used in monochromatic vision 4. Show little convergence onto bipolar cells 5. Release NT onto bipolar cells in response to light.
Are used in monochromatic vision
Sensory dermatome
Area of skin that is innervated by 1 sensory spinal nerve
Peripheral detection of thermal sensations
Arise by comparing the temp of objects and ambient air molecules to the temp of skin (about 32 degrees Celsius). Humans are sensitized to sudden changes in skin temp OUTSIDE the range of 31 to 36 degrees Celsius because that's in the thermoneutral range and anything outside of it is going to lead to either cold/warm receptors firing and allowing mechanisms to get back into thermoneutral zone
10 minutes of light/day
As little as 10 mins of light at the same time each day is enough to entrain these rhythms
Basal forebrain
BF is in the telencephalon, projects to cortex and releases Ach and GABA and is ascending, part of the RAS
Granulocytes
Basophils, mast cells, NPs, eosinophils, monocytes and MPs.
Neural pathways from the eyes
Bipolar cells of retina: 1st order neurons, retinal ganglion cells: 2nd order neurons whose axons form optic nerve, two optic nerves combine and form the optic chiasm. Half the fibers cross over to the opposite side of the brain and chiasm splits to form optic tract. Optic tracts synapse onto 3rd order neurons on the lateral geniculate nucleus of the thalamus, which send their axons to the primary visual cortex of the occipital lobe (conscious vision)
Based on the article, which of the following is TRUE?
Both caffeine and modafinil are wake-promoting and both boost levels of dopamine in the brain
109 degrees
Brain damage, shock, convulsions, respiratory collapse, likely death
EEG
Brain waves are distinguished by amplitude and frequency.
cervical dermatomes
CN V, C3-C8
Stronger depolarization during frequency coding
Can overcome the relative refractory period, generating a 2nd action potential more quickly than a weaker depolarization--stronger stimuli produce a high frequency of APs
Inhibitory modulatoin
Can turn off perception of stimulus by inhibitory modulation. They inhibit sensory and 2nd order neurons that go up to brain. These are activated by higher brain centers
What is referred pain?
Caused by multiple primary sensory neurons converging on single ascending tract, brain gets confused between signals coming from somatic sources versus those which are visceral (left arm during a heart attack, lower right arm during appendicitis
Antigen
Cellular "ID" tags (protein based), foreign antigens trigger the immune response. Antibodies mark antigens or clump them together, making it easy for WBCs to destroy them.
Step 1 of Inflammatory Response
Chemicals like histamine, leukotrienes, PGs and chemotactic factors are released
Inner ear
Cochlea, vestibular apparatus, nerves, fluid filled
Which of the following statements about pain transmission is FALSE? 1. When active, inhibitory interneurons block the transmission of pain from 1st order to 2nd order neurons 2. Collaterals from C fibers inhibit the inhibitory interneurons 3. Collaterals from A-B fibers inhibit the inhibitory interneurons 4. Natural opioids block the release of Substance P from primary pain fibers 5. Natural opioids act of 2nd order neurons and produce IPSPs
Collaterals from A-B fibers inhibit the inhibitory interneurons
Painful stimulus along C fibers
Collaterals from these C fibers inhibit the activity of the inhibitory interneurons--allowing transmission of painful stimuli to proceed to the 2nd order neuron. But the same inhibitory interneurons can be stimulated by collaterals from A-B fibers associated with pressure touch and vibration
88 degrees
Comatose, little breathing slow heart rate
Convergence of vision
Cones have a 1:1 communication with bipolar cells (higher acuity), multiple rods converge onto 1 bipolar cell. Overall, rods outnumber cones about 20:1
Internal "Core"
Consists primarily of organs inside the head and trunk.
Vestibular apparatus
Contains receptors for equilibrium
Which of the following is NOT an example of a behavioral thermoregulatory response? 1. Controls of skin blood flow 2. Sprawling out 3. Huddling up 4. Clothing 5. Shelter
Control of skin blood flow
Bitter
Could be toxins, can serve a protective function, detected by G protein coupled receptor
Which of the following is NOT a mechanism that the hypothalamus uses to regulate body temperature? 1. Sweating 2. Countercurrent heat excahnge 3. Vasoconstriction 4. Non-shivering thermogenesis 5. Vasodilation
Countercurrent heat exchange
Anterolateral/Spinothalamic tract
Crude touch/pressure, pain and temperature. 1st order neuron from DRG enters via the dorsal horn of teh SC and synapses there with the 2nd order neuron, the 2nd order neuron decussates and synapses with the thalamus: some 2nd order neurons synapse onto the ventroposterolateral nucleus (VPL) of the thalamus: VPL (3rd order neurons) projects to the somatosensory cortex. Some second order neurons synapse onto the medial thalamus: (3rd order neurons) sends information to the Limbic System (amygdala and hypothalamus): underlies the emotional and autonomic components of pain.
At rest
Cupula stands upright, during rotation acceleration, endolymph moves inside the semicircular canals in the direction OPPOSITE the rotation (it lags behind due to inertia). Endolymph flow bends the cupula and excites the hair cells.
CD8+
Cytotoxic T cells, like NK cells, but their recognition of pathogens is much more specific. They kill virus-infected cells by secreting proteins that penetrate and puncture cell's membrane. This shuts off replication of the pathogens
Filliform
DO NOT have taste buds but detect touch and texture. Fine, cone-shaped, and on the middle surface of the front 2/3 of the tongue (this is where somatosensation comes from)
Below 79
Death due to respiratory arrest
Adenosine and sleep
Decreases with sleep, works on several brain structures involved in sleep-wake such as BF, VLPO and LDT/PPT
Axons from the nasal side of the retinas... 1 Remain ipsilateral 2. Only project to the suprachiasmatic nucleus of the hypothalamus 3. Decussate at the optic chiasm 4. originate from amacrine cells 5. Only project to the pretectal nucleus in the midbrain
Decussate at the optic chiasm
Stage 3 and 4
Delta waves, 0.5-4 Hz decreased frequency and high amplitude, stage 3 is when vital signs change--BP, pulse and breathing rates drop (reached in 20 mins) stage 4 is deep sleep and is difficult to arouse. Known as Slow Wave Sleep due to delta waves and deep sleep
Pitch distinguished by cochlea
Depends on which part of the basilar membrane vibrates: at basal end, membrane attached, narrow and stiff--brain interprets signals as high pitched. At distal end, 5 times wider and more flexible--brain interprets signals as low-pitched
Lymphoid progenitor cells
Derived from hematopoietic stem cells. Differentiate into T and B lymphocytes and NK cells which further differentiate into Helper T cells, regulatory cells, cytotoxic cells and B lymphocytes differentiate into plasma cells and antibodies.
Sweet
Detect carbs, detected everywhere, detected by G protein coupled receptors, helps to enable the detection of essential nutrients
Visceral receptors
Detect stimuli that arise within the body
Muscle spindles
Detects proprioception, Uses A-alpha fibers to relay information and is part of the dorsal column/lemniscal tract
IgA
Dimer- secreted into mucus, tears, saliva, colostrum
Receptor potential
Do no necessarily generate APs themselves but will still have a change in membrane potential and will activate VG Ca2+ channels and will release NTs.
Antiviral proteins (interferons)
Do not kill the viruses but block replication in cell
Outer hair cells
Don't send out but receive efferent signals, modulating but contracting and relaxing stiffness of membranes above it and fine tune the cochlea. The terminations of the outer hair cells are almost all from axons that arise in the brainstem. Likely that the outer hair cells fine tune the frequency-resolving power of the cochlea by actively contracting and relaxing, this changing the stiffness of the tectorial membrane at particular locations. Three rows of outer hairs.
What pathway underlies "blindsight"?
Dorsal pathway is the one that most likely underlies blindsight
Vasoconstriction and vasodilation
Due to contraction or relaxation of vascular smooth muscle, and controlled by areas in posterior and anterior hypothalamus respectively
What is enkephalin
Endogenous analgesia--the brain is also capable of blocking pain to produce analgesia (weakening or blocking pain). Descending pathways: travel through the thalamus, inhibit nociceptor neurons in the SC. Inhibitory interneurons in the SC synapse with the 1st order neurons and 2nd order "pain fibers"
Prostaglandins (PGs)
Endogenous pyrogens are mediated by PGE2 synthesis (inhibited by aspirin, Tylenol)
Rotational deceleration
Endolymph keeps moving in the direction of rotation, Endolymph flow bends the cupula in the opposite direction from acceleration and inhibits the hair cells
Rotational movement slowing
Endolymph keeps moving in the direction of rotation, endolymph flow bends the cupula in the opposite direction from acceleration and inhibits the hair cells
Rotational accelerationg
Endolymph moves inside semi-circular canals in the direction OPPOSITE the rotation. Endolymph flow bends the cupula and excites the hair cells
What are phagocytes and why are they important
Engulf bacteria, release toxic chemicals, present antigens. They are NPs, MPs, eosinophils. WBCs--migrate into connective tissue, the "clean up crew": phagocytose the debris and digest via lysosomes. NPs: enter first then MPs (derived from monocytes), eosinophils: involved with parasitic infections and antigen-antibody complexes
1st way enkephalin acts
Enkephalin can bind to opiate receptors on the 2nd order neuron and produces inhibitory post synaptic potentials (IPSPs)--make neuron less likely to fire--hyperpolarized
A2A receptors
Excite neuronal activity and are expressed in the ventrolateral preoptic nucleus of the hypothalamus (VLPO)
Below 96 degrees
Extreme shivering, loss of movement, confusion, slow heat beat, shallow breath
Awake Brain Waves
Fast and high frequency, but low amplitude 13-32 Hz, beta waves
DCML
Fine touch/vibration/proprioception--Meissner's, Merkel's, Pacinian and Ruffini 1. Receptors--DRG (1st order)--Medulla (2nd order and decussates here)--VPL (3rd order)--SS cortex 2. Receptors--Trigeminal ganglia (1st order)--Trigeminal nucleus (2nd order and decussates in the VPM)--VPM (3rd order)--SS cortex
Phasic receptors
Fire when the first stimulus is received, then switch off when the stimulus is at constant intensity: Used for non-threatening situations, such as thermoreceptors, touch--pacinian corpuscle
Primary humoral response
First infection has naive B cells, which become activated B cells which are short lived plasma cells in lymphoid organs, low level antibody production, long lived plasma cells in bone marrow
Stapes
Footplate rests on the oval window
Neural Sensory Receptors
Free Nerve Endings, Simple receptors. Neural receptors that have free nerve endings have dendrites that sense whatever stimulus is being sent out, AP is generated by stimulus acting on neuron itself, generator potentials
Tympanic membrane (ear drum)
Freely vibrates when sound waves hit it, suspended in a ring shaped groove in the temporal bone, vibrates freely in response to sound. Causes movement of the three bones in middle ear
Pinna
Funnels sound waves down ear canal
Which of the following best describes "clock genes"? 1. Genes that are only present in the SCN 2. Genes that have a transcription-translation negative feedback loop which takes about 24 hrs to be completed 3. Genes associated with the homeostatic regulation of sleep 4. Genes expressed in the cerebellum which allow us to perceive the passage of time 5. Genes expressed in the hippocampus that allow for memory associated with events that happen at the same time.
Genes that have a transcription-translation negative feedback loop which takes about 24 hrs to be completed
What determines the rate at which the body breaks down caffeine
Genetics
Generator potentials
Get a change in voltage and can get an AP
Which of the following is TRUE regarding the olfactory system? 1. Mitral and tufted cells are two types of neurons found in the olfactory epithelium 2. Glomeruli in the olfactory bulb receive projections from olfactory sensory neurons that all express the same receptor 3. Olfactory sensory neurons can express several different types of receptors 4. Olfactory sensory neurons are bipolar neurons that do not fire action potentials 5. Information from olfactory bulb neurons gets relayed through the thalamus before being sent on to the gustatory cortex
Glomeruli in the olfactory bulb receive projects form olfactory sensory neurons that all express the same receptors
Process C and S
Greatest distance between these 2 are when you feel sleepiest. They interact to influence when we have the greatest urge to sleep
Transient Receptor Potential Channels
Have 6 transmembrane domains, have tetramers and an ion-conducting pore, nine thermosensitive TRP channels have been identified, each with a different temp sensitivity
Based on the video and the article, which of the following is FALSE?
Ibuprofen seems to reduce pain sensitivity in sleep deprived mice, independent from the effects of caffeine
Entraining circadian rhythm
Immediately after the chiasm; a few optic nerve fibers instead project to the hypothalamus; SCN
The cell bodies of the 3rd order neurons in the pathway for conscious vision are... 1. Retinal ganglion cells 2. In the lateral geniculate nucleus of the thalamus 3. In the primary visual cortex of the occipital cortex 4. In the superior colliculus of the tectum 5. In the visual association cortices
In the lateral geniculate nucleus of the thalamus
Parafacial zone (PFZ)
In the medulla and releases GABA (projects to parabrachial nucleus is ascending and descending.
Parabrachial nucleus
In the pons and projects to BF and cortex and releases glutamate and is ascending. Part of the RAS
Fever and Hypothalamus
Increases body temp's set point
How does fever help
Inhibits bacterial growth, stimulates phagocytosis, speeds up repair of tissues, causes liver and spleen to store iron, reducing blood iron levels (bacteria need large amounts of iron to grow)
What type of retinal cells, and what photopigment, are responsible for circadian photoentrainment
Intrinsically-photosensitive retinal ganglion cells that contain the photopigment melanopsin are responsible for entraining the SCN to the light-dark cycle and also underlie the pupillary light reflex. This, rods and cones and even conscious vision are not required for circadian rhythmicity or pupil constriction.
Off center cells
Ionotropic receptors, activated by glutamate
H+ Gradient
Is uncoupled to ATP production in non-shivering thermogenesis. Uncoupling Protein 1 (thermogenin): enables movement of protons across mitochondiral membrane without ATP production. Fat is burned without producing ATP, and heat is released instead.
2nd way enkephalin acts
It binds to the 1st order neuron and inhibits the release of substance P
Which of the following is TRUE regarding caffeine?
It competes with adenosine for its receptors but does not activate them
Which of the following is true regarding adenosine?
It is a byproduct of the breakdown of the ATP used for energy when cells are active
Substance P
It is a neuropeptide, acting as a NT and as a neuromodulator
Which of the following is FALSE regarding BAT? 1. It contains an uncoupling protein that prevents the generation of ATP 2. It appears brown because it has a high density of mitochondria compared to white adipose tissue 3. Produces heat because its cells use the enzyme ATP synthase 4. It is regulated by the sympathetic nervous system and the hypothalamus 5. It contains B-adrenergic receptors that bind norepinephrine
It produces heat because it cells use the enzyme ATP synthase
REM sleep symptoms
Known as "active sleep" and "paradoxical sleep, rapid eye movements under eyelids, complete atonia of the skeletal muscles, myoclonic twitches appear (only in early development), vital signs increase compared to NREM, EEG resembles awake person (high theta) vivid dreams, penile and clitoral tumescence, body temp not well regulated.
What functions does fever serve?
Laboratory animals prevented from developing fever following infection have higher mortality, it gets hot and helps stop the growth of pathogens
Which of the following statements is true? 1. During a high intensity stimulus, a neuron may overcome the absolute refractory period 2. you can lessen perception to stimuli via excitatory modulation 3. The larger the receptive field the greater the acuity 4. Lateral inhibition can help determine the precise location of a stimulus 5. Insensitive regions have a 1:1 ratio of the 1st to 2nd order neurons
Lateral inhibition can help determine the precise location of a stimulus
LDT/PPT
Laterodorsal tegmental nucleus (LDT) releases Ach and the pedenculopontine tegmentum (PPT) releases Ach and glutamate, these are both in midbrain and projects to thalamus) these form a complex and are part of RAS
Hearing and equilibrium are both dependent on what kind of sensory receptors? 1. Chemoreceptors 2. Proprioceptors 3. Mechanoreceptors 4. Nociceptors 5. Thermoreceptors
Mechanoreceptors
Middle layer of eye
Lens: focuses light of retina, Iris: pigmented smooth muscle, Pupil: Hole in iris allows for light to come in and focus it on the back of the eye, bipolar cells and amacrine cells
Chemotaxis
Leukocyte migration towards the site of injury (locomotion oriented along a chemical gradient)
Step 3 of inflammation
Leukocytes (WBCs) are recruited via margination (leukocytes assume peripheral portion of lumen) and diapedesis (transmigration of leukocytes across the endothelium). Also cells undertake chemotaxis (leukocyte migration towards the site of injury--locomotion oriented along a chemical gradient) and migrate toward (up the gradient) of chemical agents (bacterial secretions)
Margination
Leukocytes assume peripheral portion of lumen
Rolling and adhesion
Leukocytes tumble slowly along the endothelium and adhere transiently detach and bind again
Light entering the eye
Light enters through the front of the eye and travels to the rods and cones in the outer segments or the retina, travels to the bipolar cells, which is a special type of neuron found only in the eye. Primary neurons of the visual pathway, these then travel through the nerve fibers to the optic nerve.
REM behavior disorder
Loss of normal muscle atonia during REM sleep. Strong predictor of future synucleinopathy (neurodegenerative diseases such as Parkinson's or Lewy body dementias) Cause is unclear but lesions in certain areas of the pons and medulla can produce similar behavioral phenotype in animals
Which of the following best describes how the cochlea distinguishes between loudness and pitch
Loudness is detected by how VIGOROUSLY the basilar membrane vibrates and the frequency of APs produces, whereas pitch is detected by which part of the basilar membrane vibrates
Sour
Low pH (high [] of H+ ions, can serve protective functions, and is detected by ion channels
Cytotoxic cells
Lymphocytes and plasma cells
MHC
Major histocompatibility complex, in all vertebrates, there is genetic variation in all MHCs and play an important role in antigen recognition by T cells
Middle ear
Malleus, incus, stapes, oval window, round window and eustachian tube, air filled
Transduced in regards to a stimulus
Means to convert the energy of the stimulus into changes in membrane potential. This results in generator potentials (neural receptors) or receptor potentials (non-neural)
Countercurrent heat exchange
Mechanisms of minimizing heat loss through heat recycling within the body (and prioritizing the core). Warm blood passes down arteries and transfers heat to colder blood returning from the veins, allows extremities to receive oxygen and nutrients with minimal heat loss.
2nd order neurons of cerebellum (vestibular pathway)
To cerebellum via the inferior cerebellar peduncle
Humoral immunity
Mediated by antibodies produced by effector B cells--antibodies are present in the blood, lymph, and other bodily fluids and tissues. Critical in defense against extracellular pathogens, microbial toxins, and other extracellular substances
cell-mediated immunity
Mediated by effector T cells that produce their effect by direct contacy with target cells. Critical in defense against intracellular pathogens and tumor cells
106 degrees
Medical emergency--fainting, vomititing, dizziness, delirium
Tonotropic
Medium frequency, vibrate the basilar membrane near its middle
On center cells
Metabotropic receptors that are inhibited by glutamate
PB (Pons), SLD (Pons)
Metencephalon
97 degrees Fahrenheit
Mild to moderate shivering and progresses to hypothermia at 95 degrees
Group B
Moderately myelinated, visceral/autonomic
Amacrine cells and Horizontal cells
Modulate communication (similar to lateral inhibition)
Inner and outer segments of rods and cones
Molecules that absorbed light are found in the outer segment (disks). Rhodopsin is in rods and photopsin is in cones
APCs
Monocytes, MPs, lymphocytes, plasma cells and DCs
IgG
Monomer-main blood antibody of secondary responses, neutralize toxins, opsonization, Fc binds to phagocytes
Gamma fibers
Motor, intrafusal, except FNBS, AL/ST
Mechanoreceptors
Movement: pressure (baroreceptors), cell stretch (osmoreceptors), vibration, acceleration and sound
Fungiform Papillae
Mushroom shaped, taste buds located on top surface, found of anterior 2/3 of tongue and innervated by the facial nerve CN VII
PFZ (medulla)
Myencephalon
Step 4 of inflammation
NPs, eosinophils and MPs clean up the area
Phagocytes
NPs, eosinophils, monocytes and MPs
Salty
Na+, K+ receptors enable the detection of essential nutrients. Detected by ion channels
Which of the following statements about narcolepsy is false? 1. Narcoleptics have excessive daytime sleepiness 2. Some narcoleptics have cataplexy, a sudden loss of muscle tone during wakefulness 3. Narcoleptics act out their dreams 4. Some narcoleptics experience sleep paralysis, where they wake up and are unable to move 5. Narcolepsy is caused by a loss of orexin neurons
Narcoleptics act out their dreams
XI motor nucleus
Neck muscles= vestibulo-ocular reflex: keeps eyes fixed ahead while walking. SC motor neurons to extensor muscles (vestibulospinal tract), cerebellum (via the inferior cerebellar peduncle), ventral posterior thalamus, and then on to vestibular cortex (awareness of balance).
Why may caffeine tolerance develop
Neurons have generated more adenosine receptors so more caffeine is needed to bind to them
Orexin
Neurons of the lateral hypothalamus (LH) serve as a "finger on the switch" to promote consolidated wakefulness/sleepiness
Temperature ranges for normal body temp
Normal body temp is 98.2 or 36.78 but varies between 97 and 100,
non-shivering thermogenesis
Occurs in BAT, and to lesser extent in the liver. Regulated by SNS via NE, thyroid hormone and leptin, acclimatization to cold can increase BAT in adults. Controlled by areas in the posterior hypothalamus.
Major components of the olfactory system
Olfactory epithelium, Olfactory bulb, Olfactory cortex
Which of the following might partially contribute to Jo's reported emotional characteristics
One way physical pain and emotion are linked is because the anterolateral tract has a division that relays pain information to the limbic system through the medial thalamus
Which of the following statements about visual processing is FALSE? 1. The fovea contains cones 2. Only bipolar cells of the visual pathway can generate APs 3. Photoreceptors release NT in the dark 4. Light hyperpolarizes photoreceptors 5. Light decreases cGMP levels
Only bipolar cells of the visual pathway can generate APs
In darkness
Opsin and retinal are bound together (11 Cis configuration) cGMP-gated channels open, allowing cation influx, voltage-gated Ca2+ channels open in synaptic terminals, NTs is released continuously--glutamate, NT causes IPSPs in bipolar cell. Hyperpolarization results, Hyperpolarization closes voltage gated Ca2+ channels inhibiting NT release, No EPSPs occur in ganglion cell, No APs occur along the optic nerve
What is opsonization? And why is it important?
Opsonins (complement proteins or antibodies)--coat bacteria and promote attachment of microorganisms to phagocytose. Opsonin coats pathogen to make it appear different and thus recognizable by MPs
Dorsal Pathway of vision
Originates from the primary visual cortex, the dorsal pathway is more vision for action--moving out of the way, manipulating objects to see where they are in space. These travel to the parietal cortex where association areas are
Ventral pathway of vision
Originates from the primary visual cortex: ventral pathway is the what pathway--used for identification of objects and faces, and conscious ability to see anything, these travel to the inferotemporal cortex where association areas are
Pupillary light reflex
Others project instead to structures in the midbrain in the pretectal nuclei
Visual reflexes
Others project instead to structures in the midbrain: superior colliculi in the tectum
3 layers of the retina
Outer: photoreceptors, Middle: bipolar cells, Inner: ganglion cells
Which of the following statements about the determination of a stimulus' location is TRUE? 1. Lateral inhibition helps to identify the area of strongest stimulation by exciting transmission of action potentials from neurons adjacent to the strongest area of activation. 2. The smaller the receptive fields in an area, the less accurately we can determine the location of a stimulus 3. Convergence of multiple 1st order sensory neurons onto a single 2nd order neuron helps to isolate the precise location of the stimulus 4. Frequency of AP generation is responsible for identification of stimulus location 5. Overlapping of receptive fields are helpful in determining the location of the stimulus
Overlapping of receptive fields are helpful in determining the location of the stimulus
Narcolepsy symptoms
Overwhelming sleepiness, cataplexy: sudden lose of muscle tone in response to intense emotion usually positive, sleep paralysis: wake up and can't move (REM paralysis intrusion), hallucinations: possible REM imagery intrusion
What types of receptors and neurons the PGs act on
PGE2 acts on EP3 receptors in the PREOPTIC area that cause an inhibitory effect
How can PGs cause fevers?
PGE2 acts on EP3 which normally releases glutamate onto other areas of the brain, but EP3 is inhibited by PGE2 causing it to stop activating areas of the brain that cause heat dissipation, making body temp increase
Which of the following is NOT a wake-promoting brain structure? 1. Parabrachial nucleus 2. Parafacial zone 3. Basal forebrain 4. PPT/LDT complex 5. b and c are wake-promoting, but a and d are sleep promoting
Parafacial zone
What are eosinophils and why are they important
Parasite-destroying cells, the eosinophils releases cytotoxic chemicals onto the parasite and the cytotoxic chemicals kill the parasite
Dynamic Equilibrium
Perception of motion or acceleration, in car, linear acceleration detected as otoliths lag behind, bending the stereocilia and stimulating the hair cells. Because macula sacculi is nearly vertical it responds to vertical acceleration and deceleration, involves linear and angular acceleration
2nd line of defense (innate)
Phagocytes, immunological surveillance: NK cells, Interferons, Antiviral proteins, complement, inflammation, fever
Photoreceptors
Photons of light
1st line of defense (innate)
Physical barriers--skin and mucosal barriers--keep hazardous materials outside the body
Outer ear
Pinna, ear canal and tympanic membrane, air filled
Temperature generation mechanisms
Posterior hypothalamus, Utilizes BAT or somatic muscles causing shivering in the somatic motor neurons and vasoconstriction. Uses noradrenergic neurons of the SNS releases norepinephrine
MHC class I
Present antigens to cytotoxic T cells, bind CD8 adhesion molecules on cytotoxic T cell surfaces. Presence of foreign or over-abundant antigens targets cell for destruction. Bind endogenous antigens synthesized in a cell. Present on most cells
MHC class II
Present only on APCs, present antigen to helper T cells. Bind CD4 adhesion molecules on helper T cells, presence of foreign antigens induces antibody production, and attracts immune cells to area of infection
Mechanoreceptors respond to
Pressure and vibration: mainly Beta fibers
What does "adaptation" means in terms of a sensory receptor
Process in which sensory receptors decrease their response to a stimulus over time.
Soft sounds
Produces relatively slight up-and-down motion of the basilar membrane
2nd order neurons to CN III, IV, VI (vestibular pathway)
Project to CN III, IV, VI motor nuclei (eye muscles), XI motor nucleus (neck muscles) these two together form the vestibulo-ocular reflex that keeps eyes fixed ahead while walking.
Otoliths
Provide weight on top of membrane, in order to stimulate hair cells and detect motion.
Why taste buds though to include all five submodalities?
Proximity of distinct cell types enables lateral interactions between cells, could enable different response to sweet and sour than to sour alone. Several different NTs and their receptors present. Taste bud may be a functional unit or 'taste organ'
Behavioral thermoregulatory response
Putting on clothing, finding shelter, turning on AC or heat, sprawling out or huddling.
Ganglion cells
RGCs are secondary neurons and these nerve fibers make up the optic nerve, must be displaced laterally to get to fovea
Somatic receptors
Receptors detect sensations associated with receptors in the skin, as well as proprioception
What are NK cells and why are they important
Recognizes unhealthy cells (usually expressing abnormal proteins or viral proteins) and using perforin that makes a hole in the membrane, the granzymes which initiate apoptosis which is programmed cell death via gene expression
Secondary humoral response
Repeat infection starts with the memory B cells which activate a lot more B cells so a lot more plasma cells, lots more long-lived plasma cells in bone marrow as well as more memory B cells.
sensory homunculus
Represents a map of brain areas dedicated to sensory processing for different anatomical divisions of the body. The primary sensory cortex is located in the post central gyrus, and handles signals coming from the thalamus. Size represents number of receptive fields
Step 2 of inflammatory response
Response in blood vessels--vasodilate and increase capillary permeability through histamine
Reticular activating system
Reticular formation has 2 parts: nuclei of descending reticulospinal tracts (extrapyramidal system) and reticular activating system (RAS): these fibers ascend to the thalamus and cerebral cortex and help maintain the cortex in an alert state.
Inner layer of eye
Retina: neural tissue, contains rods (monochromatic) and cones (color) , Fovea: greatest visual acuity, Optic disk: blind spot--where optic nerve and blood vessels pass through retina, ganglion cells (generate APs)
12 hr light/dark cycle
Rhythms will be dirunal (day-active) or noctural depending on the animal
What is the difference between rods and cones
Rods are monochrome and low light, cones are color and bright light. The fovea contains the cones and as we move away from the fovea the ratio of rods to cones increases
2nd order neurons of SC (vestibular pathway)
SC motor neurons to extensor muscles (vestibulospinal tract)
master clock for circadian rhythms
SCN of the hypothalamus, light signals the retina that then travels to the SCN which sends these signals through the output pathway, these output rhythms--locomotor activity, body temp, hormone secrete etc. If the SCN is damage there is not discernable rhythm
Outer layer of the eye
Sclera: connective tissue, Cornea: allows light to enter, Photoreceptors: rods (monochrome/low light) and cones (color/bright light)
Adaptive immunity (specific)
Self/Non-self recognition, specificity, diversity, memory, has two subtypes--humoral immunity and cell-mediated immunity
Free Nerve endings and cold
Senses cold, uses A-delta fibers to relay information, and is part of the anterolateral/spinothalamic tract
Pacinian Corpuscles
Senses deep pressure, uses A-beta fibers and is in the dorsal column/medial lemniscal tract
Meissner's Corpuscles
Senses phasic touch, uses A-beta fibers and is in the dorsal column/medial lemniscal tract
Ruffini endings
Senses skin stretch, uses A-alpha fibers to relay information, dorsal column/medial lemniscal
Merkel's disks
Senses tonic touch, uses A-beta fibers to relay information and the ascending tract is dorsal column/medial lemniscal
Free nerve endings and warm
Senses warmth and relays information through C fibers and is part of the anterolateral/spinothalamic tract
Normal conditions in the hypothalamus
Under normal conditions the glutamate neurons in the preoptic area drive inhibition of heat generation and heat conserving mechanisms in the brainstem (via interneuron relays)
Olfactory epithelium
Sensory-contains olfactory sensory neurons, bipolar cells actually fire APs, neuronal axons project to the olfactory bulb, bipolar neurons with a dendrite that extends to the epithelial surface--end in numerous thin cilia, have an axon that projects to the olfactory bulb, undergo continuous turnover throughout life
Which of the following BEST descries the mechanism behind Jo Cameron's condition
She does not break down a pain-inhibiting substance
Which of the following is TRUE regarding anandamide and Jo's condition
She has extremely high levels of anandamide in her brain
Based on the article which of the following is TRUE regarding what scientists learned about Jo Cameron?
She has two genetic mutations, one of which was well known and fairly common, while the other was completely unknown in the scientific literature and first discovered in her DNA, and their combination leads to her unusual condition
Physiological thermoregulatory response
Shell keeping the core warm or countercurrent heat exchange and control of skin blood flow.
Extreme cold response
Shivering--temp threshold about 1 degree Celsius below vasoconstriction, anatagonistic muscle pairs are rhythmically activated, burns energy without preferentially recruited (located in core), controlled by "shivering center" located in the posterior hypothalamus (sends projections to spinal motor neurons)
Phototransduction
Signals are converted by the rods (1 type) and cones (3 types--blue, green, red). Both contain inner and outer segments
What are the various surface barriers in Innate immunity?
Skin, mucous membranes, lysozymes (tears, saliva and mucus), respiratory tract, stomach, bladder and large intestine
Based on the article, which of the following is TRUE regarding morphine?
Sleep deprivation significantly reduces morphine's analgesic effect on pain sensitivity?
Narcolepsy
Sleep disorder that results from the loss of orexin neurons
Process S
Sleep propensity increases with time spent awake and dissipates with time spent asleep (homeostatic drive)
Sleep and homeostasis/circadian
Sleep propensity increases with time spent awake and dissipates with time spent asleep (homeostatic drive), sleep propensity oscillates with a circadian variation
Process C
Sleep propensity oscillates with a circadian variation
Stage 2 sleep:
Sleep spindles and K complexes, sleep spindles have increased frequency and K complex has high amplitudes, light sleep
Which of the following is NOT a characteristic of REM sleep 1. Muscle atonia 2. Myoclonic twitches 3. Slow Waves 4. Dreams 5. Increased vital signs compared to NREM
Slow Waves
Gate control theory of pain
Somatic signals of non-painful stimuli can inhibit signals of pain at the spinal level. There are interneurons in the SC, that when active, inhibit the 2nd order neurons that transmit pain, hence perception of pain is lessened.
What are "labeled lines"?
Specific neural pathways transmitting modality information
Which of the following is NOT considered one of the classical "tastes" that works one the taste receptor cells found inside of taste buds? 1. Salty 2. Sweet 3. Spicy 4. Sour 5. Bitter
Spicy
Pathway from cochlea to auditory cortex
Spiral ganglia (1st order) sends axons as CN VIII, which terminates in cochlear nuclei of brainstem (2nd order) at junction between the pons and the medulla, cochlear nuclei then projects to the superior olivary nucleus (3rd order), which projects to the inferior colliculi (4th order) These neurons then project to the medial geniculate nuclei of the thalamus, which finally sends projections on to the primary auditory cortex in the temporal lobe
Secondary immune organs
Spleen, lymph nodes, adenoids, tonsils, peyer's patches and the appendix
NREM sleep
Stage 1, Stage 2, Stage 3, and Stage 4 of sleep
How are helper T cells activated?
Stimulated by APCs, T cell surface protein CD4 enhances activation, cytokines secreted (stimulate other lymphocytes)--IL-2 activates B cells and cytotoxic T cells. IL-1 activates helper T cells to produce IL-2.
Chemoreceptors
Stimulated by oxygen, pH, various organic molecules such as glucose
Why is the Thymus important for immune function?
T cells mature in the thymus, T cell precursors leave the bone marrow and travel to the thymus where they mature. They then travel to the secondary lymphoid organs.
Which of the following is TRUE regarding taste? 1. There is a strict topographic organization of taste buds on the tongue, with certain taste receptors only appearing in certain regions 2. All taste receptors are G protein coupled receptors 3. Each taste bud contains taste cells that express only one type of receptor 4. Taste is the only sensory modality that does not send information through the thalamus 5. Taste receptors relay information to the brain via CNs VII, IX and X
Taste receptors relay information to the brain via CNs VII, IX and X
BF and cortex
Telencephalon
Thermoneutral zone and BMR
Temp range in which basal rate of heat production is in equilibrium with the rate of heat loss. BMR is the basal metabolic rate--amount of energy expended daily at rest
What do high levels of adenosine in the brain mean?
That the person's brain has been very active
In the dorsal column tract... 1. The 1st order neuron synapses with the 2nd order neuron at the level of the SC 2. The 1st order neuron synapses with the second order neuron at the VPL 3. The 1st order neuron decussates at the level of the medulla (oblongata) 4. The 2nd order neuron decussates at the level of the medulla 5. Carries information relating to pain
The 2nd order neuron decussates at the level of the medulla
Subparaventricular Zone (SPZ)
The SPZ is an important relay between the SCN and other hypothalamic structures that play a role in particular circadian rhythms. The SCN--SPZ--DMH (dorsomedial hypothalamus) regulates rhythms of sleep-wake and feeding The SCN--SPZ--VMH (ventromedial hypothalamus) regulates rhythms of aggression
What is a receptive field
The region within which a sensory neuron can detect a stimulus
Nasal portion
The axons originating from the nasal retinas of each eye cross over to the other side of the brain
Temporal portion
The axons originating from the temporal retinas of each eye remain ipsilateral
Hypothalamus
The body's thermostat, has distinct subsets of hypothalamic neurons: have intrinsic thermal sensitivity, receive inputs from neurons in the periphery (DRG) and elsewhere is the core (including blood supply): esophagus, stomach, large intra-abdominal veins, head.
Lateral Inhibition
The capacity of an excited neuron to reduce the activity of its neighbors. Collateral projections excite inhibitory interneurons, inhibitory interneurons reduce activity of other pathways for neurons.
Modality
The energy form of a stimulus. Sensory receptors are specific for a particular modality
Frequency coding
The frequency of APs from the receptors activated during populating coding. The stronger the stimulus, the greater the graded potential and the longer the integrating center will remain above threshold. Stronger depolarization can overcome the relative refractory period, generating a 2nd action potential more quickly than a weaker depolarization. Stronger stimuli produce a high frequency of action potentials
Thermal Discomfort
The responses of behavioral and physiological thermoregulatory are motivated by the perception of thermal discomfort: when the climate is perceived to push us away from the thermoneutral zone
3rd order neurons of visual pathway
The lateral geniculate nucleus of the thalamus which send their axons to the primary visual cortex of the OCCIPITAL LOBE
Which of the following might partially explain the effects on her memory
The limbic system, which receives input from the pain pathway and regulates emotion, also plays an important role in memory. So, her insensitivity to pain and her general good mood may both reflect mechanisms that also make it harder to form memories due to altered functioning of the limbic system
What determines the size of the regions representing different parts of the body in the sensory homunculus 1. The actual size of each body part 2. The number of receptive fields in that area of the body 3. The number of motor units that innervate that part of the body 4. The types of somatosensory receptors that convey information from that part of the body 5. All regions of the sensory homunculus are the same size
The number of receptive fields in that area of the body
Population coding
The number of receptors activated. Activation of a single sensory receptor may not reach "perceptual threshold" as the stimulus intensity increases more receptors will respond. As we increase stimulus, recruit receptors on additional sensory neurons
Olfactory system in different animals
The olfactory epithelium in dogs is 100cm2 where in humans it is only 5 cm2 The olfactory bulb in rats is much larger than humans with 15 million ORNs with humans only having 12 million. Dogs have a much bigger olfactory bulb with 1 billion ORNs. Mice have about 1200 genes all for smell. Mice and humans have olfactory receptor pseudogenes
What is meant by the "modality" of a sensory receptor? 1. The particular type of energy of a stimulus that activates a receptor 2. The intensity of the stimulus detected by the receptor 3. The exact location of the stimulus detected by the receptor 4. Whether the receptor is neural or non-neural 5. Whether the receptor is tonic or phasic
The particular type of energy of a stimulus that activates a receptor
Static equilibrium
The perception of the orientation of the head when the body is stationary. When head is tilted, heavy otolithic membrane sags bending stereocilia, stimulating the hair cells
Which of the following about the spinothalamic tract is true? 1. The first order neurons decussates at the level of the SC 2. The first order neuron enters the SC at the ventral horn 3. The second order neuron decussates and then synapses in the thalamus 4. The first order neuron synapses with the ventroposterolateral (VPL) nucleus of the thalamus 5. The spinothalamic tract carries sensory information for vibration
The second order neuron decussates and then synapses in the thalamus
In warm conditions
The shell dissipates excess body heat
In cold conditions
The shell insulates the core from the environment--preserves body heat.
Which of the following is TRUE regarding temperature throughout the body? 1. Only the brain is considered the "core" 2. The "shell" is the skin of the body 3. Only vital organs of the chest and abdomen are considered the "core" 4. The shell insulates the core during warm conditions, while dissipating heat during in cold conditions 5. The shell is always slightly cooler than the core
The shell is always slightly cooler than the core
How does the size and number of receptive fields correspond to the acuity of determining the location of a stimulus in a given area?
The smaller the receptive field the more the acuity, the more receptive fields the greater acuity and receptive fields of neighboring neurons often overlap
The ion channels for hearing are located specifically in 1. tympanic membrane 2. basilar membrane 3. The stereocilia of the outer hair cells 4. The stereocilia of the inner hair cells 5. Tectorial membrane
The stereocilia of the inner hair cells
How do sensory receptors work?
The stimulus energy must be transduced and processed by the CNS. Converts the energy of the stimulus into changes in membrane potential
Oval window
The three bones press on the oval window. It is a membrane connected to the inner ear, causes fluid to move in inner ear (in cochlea).
What determines the effect of adenosine on a particular neuron
The types of adenosine receptors expressed on that neuron
Outer "shell"
Thickness of the outer shell depends on the temperature of the environment and the body's need to conserve heat, surrounds areas within body, but outside core regions
Primary immune organs
Thymus and bone marrow
Nociceptors
Tissue damage interpreted as pain; stimulated by intense mechanical, thermal or chemical stimuli
Which of the following statements about the tongue is TRUE? 1. Taste receptors are found only on the tongue 2. There are four types of papillae on the tongue, but only three of them contain taste buds 3. The tongue is innervated by CNs VII, IX and X 4. The circumvallate and the foliate papillae are innervated by the facial nerve 5. Filiform papillae of the tongue are mushroom shaped 6. Taste buds on the tongue contain bipolar neurons which fire APs and are the first order neurons of the gustatory pathway
There are four types of papillae on the tongue, but only three of them contain taste buds
How are taste buds organized?
There is no strict topographic map of taste qualities on the tongue, taste buds from all regions of the tongue contain cells that respond to all submodalities.
Thermal Receptors
Thermal receptors can also be activated by chemical ligands and the trigeminal system is affected by this as well
Delta fibers
Thermo (cold) nociceptors--sharp and localized pain (quick pain) good precision
Horizontal cells
These are stimulated if dark and inhibit if light, they do this using glycine. They become depolarized on center and hyperpolarized off center
Delta and C fibers
These neurons release substance P and glutamate onto 2nd order neurons in SC or medulla
Stage 1 sleep
Theta waves 4-8 Hz, drifting sleep
All somatosensory receptors
They are all neural receptors, different sensors are at different layers, and the 1st order neurons with cell bodies in DRG
Myeloid progintor cells
They are derived from hematopoietic stem cells, they differentiate into RBCs, platelets, NPs, eosinophils (mast cells), monocytes )MPs and DCs).
What is an interferon?
They are signaling molecules (cytokines) released by viral infected cells. These bind the receptors of neighboring cells. Promotes MP function and phagocytosis of infected cell, triggers activation of NK cells (apoptosis of the infected cell), this triggers synthesis of enzymes that inhibit synthesis of viral proteins
Ruffini ending
skin stretch
Meissner's corpuscles
Touch/pressure (phasic--fast)
Diapedesis
Transmigration of leukocytes across the endothelium
Activation of Apoptosis in target cell
Triggered by FAS-FAS ligand bind Activates JUN kinase Caspase 8 Causes destruction of mitochondrial DNA Takes about 1-2 days
Exogenous pyrogens
Typically bacterial or viral, such as lipopolysaccharides (from bacterial cell walls), activate immune cells, which release cytokines (endogenous pyrogens)
Which of the following is NOT a type of brain wave measured by EEG 1. Zeta 2. Theta 3. Alpha 4. Beta 5. Delta
Zeta
Adenosine
a byproduct of the ATP produced when cells are active, and it accumulates in certain rain areas with waking and sleep deprivation. Sleep decreases adenosine levels. Adenosine appears to work on seceral brain structures involved in sleep-wake such as the BF, the VLPO, and the LDT?PPT. The type of adenosine receptor in each area determines whether it has an excitatory or inhibitory effect
SC--pulvinar
a thalamic nucleus, pulvinar relays signals up to dorsal pathways, subcortical unconscious pathway that manipulates for movement. Damage to V, could still move around objects w/o consciously seeing them
Incus
articulates in between maleus and stapes
Round window
attached to cochlea, bulges back out and acts as another membrane allowing more fluid movement in cochlea
Malleus
attached to inner surface of tympanic membrane
sacral dermatomes
back of legs and genitals
Why is the olfactory system an exception?
because nothing goes through the thalamus
Ear canal
carries the sound waves to the tympanic membrane
Above 111
certain death
What are taste buds?
chemoreceptors, taste buds contain 50-150 taste receptor cells; elongated; extend microvilli into taste pores, send signals to gustatory sensory neurons
Eustachian tube
connects middle ear cavity to nasopharynz--equalizes air pressure of both sides of tympanic membrane, normally flattened and closed, swallowing and yawning opens it and allows throat infections to spread to the middle ear
Adaptive immunity
delayed (days, wks) specifically activated by certain components of pathogens (antigen), vaccines stimulate this type of immunity. Primary functions: clearance of infection, development of memory response
Three circular canals
detect only angular acceleration, each duct filed with endolymph and opens up as a dilated sac (ampulla) next to utricle. Each ampulla contains a crista ampullairs, mound of hair cells and supporting cells.
Umami or savory
detects amino acids, specifically glutamic acid, receptors enable the detection of essential nutrients, detected by G protein coupled receptors
Pacinian Corpuscles and vibration
detects vibration, uses A-beta fibers to relay information and is part of the dorsal column/medial lemniscal
102 degrees
extreme sweating, breathlessness, fast heart rate, convulsions in infants
REM sleep
fast and random, almost like awake waves but a little less frequency has sawtooth waves
Dorsal column system (medial-lemniscal) DCML
fine touch/vibration/proprioception (Meissner's, Merkel's, Pacinian, Ruffini), 1st order neurons (from DRG) enters via the dorsal horn of the SC and ascends to the medulla--Gracile (lower body) and Cuneate (upper body), where it synapses with the 2nd order neuron, the 2nd order neuron decussates and synapses in the thalamus: pathways from upper and lower body synapse in VPL, which (3rd order neurons) then project to relevant areas of somatosensory cortex. THose from trigeminal pathway (sensations from the face synpase in ventroposteromedial (VPM) thalamus, which (3rd order neurons) project to face region in somatosensory cortex.
lumbar dermatomes
front of legs and stomach
basilar membrane
houses the cells that bend and transmit signals
Sublaterodorsal nucleus
in the pons and plays a rold in generating REM sleep. SLD also plays an important role in producing muscle atonia during REM by releasing inhibitory NTs like GABA and glycine, in the medulla and directly onto spinal neurons that then go to muscles
Somatosensory system
in the post central gyrus, nothing is visceral, conscious sensation of touch, final stop in pathway
Proprioceptors
include golgi tendon organs and muscle spindles
Louder sounds
make the basilar membrane vibrate more vigorously: triggers greater depolarization and higher frequency of action potentials and brain interprets this as louder sound.
3 types of nociceptors
mechanical, thermal, polymodal
IgD
monomer-B cell receptor
IgE
monomer-antibody of allergy and anti-parasitic activity, Fc region binds to mast cells and basophils
Alpha fibers
motor extrafusal, proprioception, muscle spindles or golgi tendons DCML
Never Let Monkeys Eat Bananas
neutrophils, leukocytes, monocytes, eosinophils, basophils
Bipolar cells
primary neurons of visual pathway, must be displaced laterally to get to fovea
Olfactory cortex
processing
Olfactory bulb
relay station, contains glomeruli: innervated by axons from sensory neurons--axons terminate on mitral and tufted cells that project to the olfactory cortex.
Constant darkness:
rhythms "drift" by a fixed amount each day based on the internal period
Circumvallate and foliate
ridged morphology, taste buds located inside ridges, located in the posterior 1/3 of tongue, and innervated by the glossopharyngeal nerve (CN IX)
Free nerve endings
sense pain and itch, uses A-delta fibers to relay information and is in the anterolateral/spinothalamic organs
Golgi tendon organs
senses proprioception, uses fibers A-alpha to relay information and is dorsal column/medial lemniscal tract
thoracic dermatomes
top of sternum to waist, T1-12
Beta fibers
touch--all mechanoreceptors, DCML
Merkel's disk
touch/pressure (tonic--slow)
Suppressor T cells
turn off immune response when antigen is no longer present
Thermoreceptors
varying degrees of heat
