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VP Exam 2
| Question | Answer |
|---|---|
| Ion Channel | –Open/close with stimulation –Facilitated diffusion -> Current |
| Ion Transporters | –Bind to ion(s) –Use energy to move against concentration gradient –Set up concentration gradient (capacitance) that is exploited by ion channels |
| Potential | Measurement of the charge difference (voltage) across a lipid membrane. |
| Resting Potential | The charge difference across the lipid membrane in a resting cell. Typical: -70mV |
| Equilibrium Potential | For a particular ion, the potential at which there would be no net ion movement across a lipid membrane. |
| Depolarization | Occurs when the "size" (magnitude) of the membrane potential decreases and the sides of the membrane become more similar. Physiologically, the resting potential becomes less negative. |
| Hyperpolarization | Occurs when the "size" (magnitude) of the membrane potential increases; the sides of the membrane become less similar. Physiologically, the resting potential becomes more negative. |
| Re-polarization | A return to the original resting potential following a change in the membrane potential (K+ current increases, Na+ current decreases) |
| Overshoot | A reversal of charge. Physiologically, the membrane potential becomes positively charged (Na+ current favored) |
| Action Potential | An electrical signal that can travel (propagate) down an axon, which always involves an overshoot. -All or none -Non-decremental -No summation -Refreactory period (milliseconds) in which nothing happens. |
| Graded Potential | Small stimulus opens few channels (Na+: fast response)-> Small current quickly diffuses away -> Channels close (repolarization) -to achieve threshold/return from threshold -vary in magnitude according to stimulus -decremental -summation -no refractor |
| Generating an action potential | Always K+ current After stimulus, threshold is reached~15mV above rest Coordination (many Na+ respond)=snowball Dominant Na+ curr: K+ channel was triggered, slow to respond Inactivation gate close, K+ open Temp: hyper -> re Na+ move inactivated to c |
| Propagation | Stimulation of new action potentials all the way down Moves in ONE direction (Na+ channel needs time to inactivate, preventing reversal of action potential's direction) Speed of action potential depends on a ratio of transverse to longitutundinal |
| Potassium (K+) voltage-gated leaky channel | Leaky channels: K+ current at rest is stronger than Na+ current Single "gate" closed at resting potential -Depolarizing stimulus ->Slow gate opening-> Negative K+ current repolarizes-> K+ channels close -Potassium restores potential |
| Sodium (Na+) voltage-gated channel | 2 gates-(In)activation gate -rest pot-act. gate closed -Depol stim:act. gate quick opens. + Na+ current adds to depol=short-lived + feedback -W/time inactivation gate closes, Na+ current stops=repol -cant move directly back to open-must close first |
| Synapse | A specialized region of contact (physical relationship = physiological response) and communication between a neuron and its target. |
| Soma | Cell body of a neuron |
| Dendrite | Receptive portion of a neuron (receive information) |
| Axon | Stimulate other cells by sending out a signal (often by neurotransmitter release) |
| Afferent Neuron | Sensory - receive information into the CNS |
| Efferent Neuron | Motor - sends information out of the CNS (skeletal muscle, smooth muscle, glands, etc.) |
| Electrical Synapse | Membranes nearly touch. Gap junctions = no time delay (direct cytosol to cytosol). Ex: fish electric organs, mammalian hypothalamus: oxytocin, brainstem: respiration regulation |
| Gap Junction | Channel proteins span the membranes of 2 cells, meaning that currents pass directly between cells, and response has no time delay. More common in invertebrate synapses. |
| Otto Leowi | Nobel Prize for physiology or medicine in 1936. His experiment that came to him in a dream showed that we do have chemical neurotransmitters before we could actually isolate neurotransmitters (particularly acetylcholine). |
| Otto Leowi's Experiment (1-setup) | 2 frog beating hearts [stim own beating in Ringer's solution (ion balance-more Na+ than K+) with adequate oxygen] Heart 1 had Vagus nerve (parasympathetic system that slows HR) Soln from heart 1 was moving into the soln with heart 2 |
| Otto Leowi's Experiment (2-experiment/results) | Stim. the Vagus nerve to see if there was an effect on heart 2 HR of heart 1 slows -SAME RESPONSE occurs seconds later in heart 2 -Some chem was released into the Ringer's soln, which was transferred to the second container |
| Otto Leowi's Experiment (3-next step) | Repeated the experiment with the sympathetic nerve and saw an increase in heart rate in heart 2 |
| Chemical Synapse | Synapses in which vesicles release their contents. Contents travel across the synaptic cleft via diffusion and bind to target, causing a response in the target (Often ligand-gated Ion channels) |
| Advantages of Chemical Synapses | Amplification, Excitatory vs. Inhibitory, Integration, One-way Communication, Plasticity (modifiable) |
| Amplification of signal | Occurs in chemical synapse. Receptor(s) may stay on for a period of time. |
| Excitatory vs. Inhibitory signals | Some chemicals have a receptor that continues response. Others inhibit the response. Ex: flexing biceps requires relaxation of tricep. Will power = inhibition |
| Integration of signal | There are multiple inputs to a single neuron. Each neuron has 1,000-10,000 synapses (recipients/targets) |
| One-way Communication of signal | Chemical synapse only. Order of events is known. |
| Neuron Plasticity | Chemical synapses have gap junctions, making them modifiable, since there are no absolute connections. Vertebrates have a very complex and dynamic nervous system. |
| Identifying Neurotransmitters | Present in synaptic terminal, Ca2+-dependent release into synaptic cleft, artificial application, mechanism for removal, drugs: agonist vs. antagonist(can we mimic or block?) |
| Agonist | binds to the same receptor as a neurotransmitter and has the SAME effect |
| Antagonist | binds to the same receptor as a neurotransmitter and BLOCKS the effect (NOTE: it does NOT have the opposite effect) |
| Neurotransmitter release | -Packaged into vesicles that are the same size and hold the same amount of material (consistent quantity released = consistent response) -Overshoot (V is created) -Ca2+ gated V-channels open,Ca2+ rushes to term. -Ca2+ allows vesicle dock& contents rele |
| Activation of Postsynaptic Receptors | ionotropic receptors (ligand-gated ion channels) or metabotropic receptors (GPCRs) |
| Ionotropic Receptors | Ligand-gated ion channel -Quick response, neurotransmitter binds, opens channel, Na+ moves into cell and depolarization occurs -If depolarized to threshold, V-gated ion channels are stimulated and action potential ensues |
| Metabotropic Receptors | GPCR -G-protein is released, activates a 2nd messenger to change protein activity/gene expression -SLOW, long-lasting -Small stimulus: release ionotropic (1st) -Large stimulus : releases metabotropic (2nd) |
| Communication of the Chemical Synapse | Neurotransmitter release, activation of postsynaptic receptors (ionotropic/metabotropic), termination of signal |
| Termination of Signal (presynaptic neuron) | Discontinued release of neurotransmitter: -Stop action potentials in presynaptic neuron -Return to resting potential -Calcium channels close -Calcium pumped out of presynapse -Membrane recycling |
| Termination of Signal (synaptic cleft) | Removal of neurotransmitter Diffusion out of cleft Enzymatic degradation Neurotransmitter re-uptake -Metabolized product or neurotransmitter itself returned back to presynaptic neuron (recycling) |
| Termination of Signal (postsynaptic target) | Ionotropic (easy - milliseconds) -Closing of ion channels -Transport of ions across membrane Metabotropic (seconds to minutes) -Restoration of G-protein -Removal of second messengers -Inactivation of enzymes |
| Neuromuscular Junction (Fig. 12.7, 12.8) | Ca2+-dep ac.ch.release, binds to ac.ch. rec. (joint Na+/K+ channel) -Stim currents -Depol above threshold due to equal Na+ and K+ perm -Acetylcholinesterase(ac.cho-> acetate+choline):choline is recycled -Metabolism and re-uptake |
| Receptor Encoding | Stimulus modality -What is it? Intensity -How much? Temporality -When? How is it changing? Location -Where? |
| Stimulus modality | Modality: preferred stimulus for a receptor -proprioception, T, vision, pressure, taste, osmolarity, hearing, olfaction, pain Submodality: preferred range -cold vs. warm, red vs. green, sweet vs. bitter, loud vs. quiet, high pitch vs. low |
| Principle of labeled lines | Each receptor, when stimulated, gives rise to only one sensation. -Cold receptors can feel hot -Being hit in the eye: someone sees stars (modality is light), but stimulating receptors gives a 'light' sensation |
| Stimulus Intensity | Indicated by increasing the number of action potentials/time -Increased firing by a single neuron -Increased number of neurons firing -Differing thresholds -Recruitment |
| Stimulus Temporality | Tonic Receptors (slowly adapting), Phasic Receptors (quickly adapting) |
| Tonic Receptor | Slowly adapting -Continue to generate Action Potential throughout the stimulus period -Convey information about both intensity and duration -Ex: noise (constant noises aren't new info, so the brain doesn't spend time thinking about it) |
| Phasic Receptor | Rapidly adapting -Only generate Action Pot. at onset (and maybe offset) of stimulus -Convey info about change in stimulus intensity -Ex: taking off in an airplane (you feel the acceleration, but not the velocity of hundreds of miles per hour) |
| Stimulus Location | Exteroceptors, interoceptors, proprioceptors -acuity -receptive field |
| Exteroceptors | External stimuli -distance receptors (ex: visual stimuli) -contact receptors (ex: touch) |
| Interoceptors (visceroceptors) | internal stimuli |
| Proprioceptors | Stimuli: body parts relative to each other and relative to gravity |
| Acuity | Ability to discriminate between location of 2/more simultaneous stimuli -Ex: touch - 2 points close together may not be distinguishable (if the same neuron is conducting the stimulus) -vision: cones -inversely related to receptive field |
| Receptive Field | Region of receptor surface that corresponds to a single neuron -Rods -inversely related to acuity |
| Touch | Mechanoreceptors - force -Stretch-activated ion channels Send information to the Primary Somatic Sensory Cortex -Left body sends to right brain -Right body sends to left brain Face has a small touch receptive field (HIGH acuity) |
| Touch Receptors | -Meissner's corpuscle -Markle's corpuscle -Pacinian corpuscle -Raffini corpuscle |
| Meissner's corpuscle | -Close to the surface of the skin -Phasic (start and end of touch) -Superficial skin |
| Merkle's corpuscle | -Superficial part of the skin (close to surface) -Tonic (constant light pressure on the skin) -Superficial skin |
| Pacinian corpuscle | -Phasic -Subcutaneous (deep forceful changes) -Pressure initially stimulates the neuron like a water bed, then fluid between membranes settles out.After pressure is released, the fluids come back and press on the neuron until the fluids settle out |
| Ruffini corpuscle | -Tonic (strong sustained force) -Subcutaneous (deeper pressure) |
| Gustation (taste) | Chemical sense Salty, Sweet, Sour, Bitter -Pappilae (bumps) -Taste bud -Support cells (shape/structure) -Tastecells (gustatory cells): not neurons -Basalcells (stem cells - constant turnover in such a harsh environment) |
| Salty | Need Na+ and Cl- -Sodium channels always open (high permeability) -Changing concentration gradient (extracellular changes quickly) -Increasing EC conc. and permeability will raise eq. pot., making an action potential easier to trigger. |
| Sour | -Acidity (need vitamin C for connective tissue) -H+ blocks potassium channels -(loss of K+ permeability) -> depolarization because K+ is still there |
| Sweet | 2ndmessenger system Fruits (vitamins), carbohydrates |
| Bitter | -Alkaloids (poisons) -Narangin (chemical found in grapefruit) -Stimulus (receptors) affects perception |
| Umami | -Amino acids (meat) -G-protein linked -MSG (monosodium glutamate) enhances taste by affects these receptors |
| Olfaction (smell) | Chemical Sense High Sensitivity, Low specificity -processed in limbic system (memory, emotion) -olfactory epithelium:Superior concha -Humans: 2-4 cm^2 -Hounds: 20-200 cm^2 Anosmia (loss of smell) |
| Olfaction cells | -Supporting cells -Olfactory receptor cells (neurons constantly being replaced) -Basal cells (stem cells) |
| Anosmia | Loss of the sense of smell -Temporary/long-term -Causes Traumatic injury crushes holes in cribiform plate (holes in the bone for neurons to send signals to the brain) Exposure to toxic chemicals, kills neurons Zinc deficiency Aging Fewer stem |
| Hearing | Hair cells: stretch-gated ion channels -detection of mechanical forces (sound waves, gravity) |
| Ear Anatomy | -Outer ear (the part you see) -Middle ear (air-filled cavity with tiny bones) -Inner ear (fluid-filled, special organs for hearing and balance) |
| Inner Ear Anatomy | Cochlea Vestibule Semicircular canals |
| Cochlea | -Snail hell shaped -Houses hair cells involved with sound detection -Fluid-filled -Scala vestibuli: entryway -Scala tympani: exit for sound waves -Organ of Corti |
| Scala Vestibuli | Entryway to the inner ear |
| Scala Tympani | Exit for sound waves from the inner ear |
| Organ of Corti | -Hair cells sit on basilar membrane, stuck in a false ceiling called the tectorial membrane -Floor (basilar membrane) is flexible -Ceiling (tectorial membrane) is rigid |
| Vestibule | Detects position of the head -Static position of head (tonic) -Linear acceleration (phasic) |
| Anatomy of Vestibule | -Hair cells are embedded in a gel (macula) -Crystals (otoliths) distributed throughout the gel give weight to the gel Macula of utriculus parallel to base of skull -Macula of sacculus perpendicular to base of skull |
| Semicircular Canals (3) | Hair cells detect angular acc. (/\v) -Phasic receptor (changes) -Hair cells are in a gel (cupula)at the base of canals, surrounded by a fluid (endolymph) -Fluid has inertia Stabilizes at constant speed -Moves in the direction the container HAD BEEN |
| Semicircular canals and Movement | Beginning: Head moves L, fluid moves R (relatively), gel moves, hair cells bend Maintenance: continuous movement - no fluid moves (stabilized) End: Head stops moving L, fluid moves L -Visual input tells the brain that the head is stopping, not moving |
| Semicircular canals: sickness | ->Seasick: Overstimulation ->Space sick: Lack of stimulation |
| Basilar Membrane (pitch-frequency) | Basal end (where sound is coming into cochlea) -Near oval window,dense tissue, difficult to vibrate -High frequency=high E,tones,pitch Apical end (distant side) -Near round window,Less dense tissue,easier to vibrate -Low freq=low E,tone,pitch |
| Basilar membrane (volume-amplitude) | High amp=high vol -Diff hair cells have diff thresholds -High threshold = high vol (recruitment) -Bleeding of the pitch (at loud volumes, adjacent hair cells will be pulled along as basilar membrane moves a LOT toward the tectorial membrane) |
| Rod | Convergent information -low light conditions, weakly interacts w/opsin (requires not much energy to convert retinal to trans) -Several rods send info to one bipolar cell (pixilated image) -Increased sensitivity -Decreased acuity |
| Cone | -bright light conditions, strongly interacts w/opsin (requires a lot of energy to convert retinal to trans) -One cone sends info to one bipolar cell (small receptive field) -Decreased sensitivity -Increased acuity |
| Myopia | Nearsightedness Eyeball is too long |
| Hyperopia | Farsightedness -Eyeball is too short, not enough space to focus scattered light |
| Presbyopia | Aging of the lens Decreased lens elasticity -loss of muscle tension doesn't result in rounding of lens -harder to focus near objects -near point of focus moves farther away |
| Avian vision | Small, light skulls -Most of volume is taken up by eyes -Eyeball is not round ->Bulge out of the skull Both lens AND cornea can flatten/round up -Enlarges the range at which they can focus -Distant and close-up vision are BOTH enhanced |
| Neuron anatomy | Soma: cell body Dendrites: receive information Axon: stimulates other cells (often by neurotransmitters) |
| Neuron categories | Afferent: sensory-info to CNS Efferent: motor-info out of CNS Interneurons: between neurons, largest category (>99%) Simulus->sensory neurons->CNS neurons->motor neurons->effectors |
| Brain Tissues | Gray Matter:Cell bodies, dendrites, & synapses -Organized as nuclei; brain cortex White Matter: Myelinated axons (speeds up the signal)- oligodendrocytes -Organized as neural tracts (in the brain) or nerves (in the body) |
| Nerve | Bundle of neurons (axons)in PNS -can be sensory, motor, or autonomic Categories: -Cranial nerves (come off the brain) -Spinal nerves (come off the spinal chord) tend to be more specialized |
| Hindbrain | Cerebellum, pons, medulla oblongata |
| Cerebellum | -Muscle coordination through muscle feedback -Balance and posture -Speech -After movement, proprioceptive info is sent back to the brain to ensure the movement was correct -Sensitive to alcohol |
| Pons | Bridge:: Traffic hub-Ascending tracts, Descending tracts -Sleeping/waking -Respiration (assists medulla oblongata) |
| Medulla Oblongata | -Coordinates many essential reflexes -Swallowing/vomiting -Regulation of heart rate -Regulation of breathing rate -Sensitive to opiates |
| Midbrain | -Pathway for ascending & descending tracts -Auditory reflexes -Visual reflexes ->Brain can remain on a point of focus as the head moves ->Changing pupils, lens length |
| Forebrain | Cerebrum, diencephalon |
| Cerebrum | Occipital lobe, temporal lobe, parietal lobe, frontal lobe |
| Occipital Lobe | Primary visual cortex, located in the back |
| Temporal Lobe | Hearing/language, located on the sides |
| Parietal Lobe | Primary sensory cortex, association areas (brain coordination), located forward from the occipital lobe |
| Frontal Lobe | Motor cortex/human traits (The front portion is the prefrontal cortex: will (wanting and controlling/imagination/language/rationality), located in the front |
| Diencephalon | Thalamus, hypothalamus |
| Thalamus | Coordinates sensory information except olfactory |
| Hypothalamus | Autonomic nervous system (ANS) -pituitary gland -temperature regulation -motivation/drive (hunger, libido) |
| Brainstem | Basic essential survival (breathing, heart regulation, coughing, swallowing, simple digestion) -midbrain, pons, medulla oblongata |
| Principles of Brain Organization | -Brain function SOMEWHAT localized -Brains have maps -Size matters -Vertebrate brain evolution=repeated expansion of forebrain -neural circuits are plastic |
| Encephalization Quotient (EQ) | As body gets bigger, brain doesn't get bigger linearly -Logarithmic -Humans: 7.5x bigger than expected for a species our size ( we have more neurons than we need for normal body function -Apes and dolphins: 5x |
| Autonomic Nervous System (ANS) | Targets smooth muscle (digestive tract, ciliary muscle-eyes), cardiac muscle, glands -House-keeping/protection (conserves energy, nutrient storage, protection from irritants) |
| Endocrine | signaling within the body (long distances) |
| Exocrine | releases into open space (digestive tract) |
| Parasympathetic (ANS) | Long preganglionic neuron, short postganglionic neuron -top and bottom of spinal chord -activates a SPECIFIC target |
| Sympathetic (ANS) | Short preganglionic neuron, long postganglionic neuron -central region of spinal chord, -broad in effects, general response, long lasting -hormones from adrenal gland (epinephrine, norepinephrine)=fight/flight, prepares body for stress, /\activity |
| Parasympathetic Actions | Pupil-constriction Salvation-watery part of saliva Bronchiole-constriction limits irritants HR-Vagus nerve slows HR (conserves energy) Digestion-GI motility (get nutrients) Defecation/urination-dilation increases waste removal Penis/clit-blood flow |
| Sympathetic Actions | Pupil dilates for more info Saliva-mucousy reduces water loss Bronchiole-dilates to breathe easier HR-increases Digestion-slowed Defecation/urination-inhibited Penis/clitoris-ejaculation/orgasm |
| Enteric Nervous System | "brain of the guts" contained w/in GI tract -complex network of interconnected ganglia -coordinates intestinal peristalsis -adjusts blood flow to gut -regulates release from glands |
| Biological Clock: endogenous rhythm | -Free-running rhythm (measured w/o environmental cues) -Period: one cycle of endogenous rhythm (approx. 24 hrs.) -Entrainment: synch endogenous rhythm w/environmental stimuli (phasing factor) |
| Phasing Factor | environmental cue capable of entraining a biological rhythm ex: sunlight |
| Rhodopsin | Light-absorbing pigment in the eye containing Retinal + Opsin |
| Retinal | Portion of a photoreceptor that is in the cis form and interacts with the opsin pocket when light is absent, but changes to trans and activates transducin when light is detected |
| Opsin | Portion of a photoreceptor that is a G-protein linked transmembrane protein that interacts with the cis form of retinal. 4 forms (3 cones-red, green, blue, 1 rod) |
| Transducin | G-protein that is activated by retinal interaction (in the trans form), its action is to activate cGMP phosphodiesterase |
| cGMP phosphodiesterase | activated by transducin, converts cGMP to 5'GMP |
| cGMP | interacts with Na+ channels to keep them open and release neurotransmitters in dark conditions |
| 5'GMP | form of GMP present in light conditions. Cannot open Na+ channels, preventing neurotransmitter release |
| Photoreceptor in Dark | -Rhodopsin intact (cis form) -Ion channels open (predominantly Na+ channel) under the influence of cyclic GMP -Depolarized membrane potential -Releasing neurotransmitter when NOT stimulated |
| Photoreceptor in Light | -Trans-Rhodopsin -G-protein (transducin) -Cyclic GMP attached to Na+ channels to keep them open -Loss of cGMP (by cGMP phosphodiesterase) closes Na+ channel -Repolarization(hyperpol) of membrane potential (negative) -NO release of neurotransmitter |
| Light signal pathway | received through the pupil, absorbed by rods/cones, travels to bipolar cells, transmits to ganglion cells which form the optic nerve and exit the eye through the optic disk |
| Ganglion cells | Cells that form the optic nerve and receive signals from rods and cones |
| Bipolar cells | transmit info from photoreceptors (rods/cones) to ganglion cells. Many rods to one bipolar cell, only one cone per bipolar cell. |
| Fovea Centralis | Region of the retina where the point of highest focus occurs. Located at the back of the eye. |
| Optic disk | Exit from the eye for ganglion cells (optic nerve). -"blindspot" isn't apparent because there are 2 eyes which are constantly moving, and the brain fills in missing information. |
| Focusing far objects | Lens is relaxed (enlarged) and flatter |
| Focusing near objects | Lens is contracted by the ciliary muscle and is very round. |
| Ciliary Muscle | Muscle in the eye that changes the shape of the lens. Bigger diameter = more flat = relaxed |
| Passive Focusing | Occurs with distant objects, when the ciliary muscle is relaxed and the lens in enlarged. The lens is flatter and less light bending occurs. |
| Active Focusing | Occurs with near objects, when the ciliary muscle is contracted and the lens is compact and round. More bending of light occurs. |
| Somatic Nervous System | Coordinates skeletal muscle and voluntary movement. |
| Superchiasmatic Nucleus (SCN) | Located in the hypothalamus above the crossing of the optic nerves. Responsible for maintaining the biological clock via input from the retina. -In blind people, nerves are still intact, so biological clock may be maintained. |
| Pineal Gland | Controlled by superchiasmatic nucleus -releases melatonin, the "darkness hormone," at night. |
| Circadian Oscillator | Time-keeping mechanism within cells depending on alternating expression of key clock genes, and is temperature-independent. |
| Nervous System | neuron releases a neurotransmitter into a synapse (focused response) for a quick on/off response. Intensity of signal depends on frequency of action potentials. |
| Gland | gland releases a hormone into the blood for broad, slow, long-lasting effects. Intensity of signal depends on amplitude (blood concentration of hormone) |
| Neuroendocrine | neuron releases chemicals (neurohormone/hormone) into the blood instead of a synapse (quick and coordinated responses with long-lasting effects. |
| Paracrine | "Next to": chemical is released and doesn't make it to the blood, but instead influences neighboring cells |
| Endocrine | Chemical released has an effect on the self |
| Hormone Secretion Patterns | Chronic hormone secretion Acute hormone secretion Cyclic hormone secretion |
| Chronic Hormone Secretion | -Hormone concentration maintained relatively constant in blood -Very tight negative feedback regulation |
| Acute Hormone Secretion | -Hormone levels increase dramatically in response to stimulus, after which hormone levels return to normal -Ex: glucose -> insulin release -Ex: stress -> cortisol release |
| Cyclic Hormone Secretion | -Regular pattern of hormone release -Generally controlled by central nervous system -Ex: cortisol released before waking -Ex: estrogen/progesterone -Ex: growth hormone melatonin released during deep sleep |
| Types of Hormones | Steroids Fatty Acid derivatives Proteins Modified amino acids |
| Steroid | Type of hormone that is derived from cholesterol and: -Can’t be stored (lipid-soluble) -May pass directly through the lipid membrane -Acts at intracellular receptors -Change gene expression (DNA level response) |
| Fatty Acid Derivatives | Type of hormone that: -Made from fatty acids in cell membrane (Prostaglandins derived from fatty acids) -Typically autocrine or paracrine -Ex: immune response, inflammatory response |
| Protein | Hormone -Made in rough ER -Glycoprotein (hormones - not neurotransmitters):Attached carbs, longer half-life -G-protein receptor:increase 2nd messenger to change enzyme activity in cell -Tyr kinase receptors:Active once 2 monomers together, receptor=st |
| Modified Amino Acids | -Catecholamines (dopamine, epinephrine, norepinephrine) -Tryptophan Derivatives (melatonin, seratonin) -Thyroid Hormones |
| Catecholamines | -Dopamine, norepinephrine, epinephrine -Derived from tyrosine - bind to membrane proteins (can't cross through the membrane), usually ion channels -May be neurotransmitters or hormones |
| Tryptophan Derivatives | 2 pathways: -Tryptophan -> Melatonin by pineal gland -Tryptophan -> seratonin (neurotransmitter/hormone) |
| Thyroid Hormones | -Modified by tyrosine -Iodine attached (3 or 4) -Lipid-soluble: act on the DNA to affect gene expression ->Stored as a protein to be chopped |
| Regulation of Hormone Release/Actions | -Negative feedback -Receptor numbers -Half-life |
| Hormone Regulation: Negative Feedback | 3-steps:Hypothalamus,Pituitary,Target -Short loop(2 levels) ->Hormone (TSH) stimulates target (T3 or T4), which immediately give negative feedback to TSH -Long loop (3/more levels) ->Ex: TRH stimulates TSH to stimulate T3 and T4, which inhibit TRH |
| Hormone Regulation: Receptor Numbers | IF Lower hormone levels -Increased receptor number -High sensitivity IF Higher hormone levels -Reduced receptor number -Less sensitivity Pathology: Type II Diabetes Mellitus -Constant insulin release causes de-sensitivity to insulin |
| Hormone Regulation: Half-life | Determined by: -Enzymatic Activity:Liver (esp.steroid hormones) -Protein vs. Glycoprotein(longer half-life) -Reversible binding to plasma protein _Can't be attacked by enzymes _Can't bind to receptor PT3 <-> P + T3 T3 drops, eq. shift to R, more fr |
| Hormone Half-life | Time it takes for half the hormone to be inactivated or eliminated (given release is not continual) |
| Pituitary Gland | Below the hypothalamus, 2 glands w/2 tissue types -Posterior pituitary -Anterior pituitary -Pinch off part of the developing material of the mouth -Pars intermedia (in humans, lost in development) |
| Posterior Pituitary | (neurohypophysis): extension of the hypothalamus (axons and terminals located in the pituitary, soma in the hypothalamus) -directly affected by the brain |
| Anterior Pituitary | -Roof of the mouth -Gland tissue -Indirectly affected by the brain -Dynamic (cells grow and die rapidly) |
| Tropic Hormones | -Stimulate the release of a second hormone -Stimulate growth of the target endocrine gland -Most neurohormones of hypothalamus are tropic hormones -Most anterior pituitary hormones (such as TSH) are also tropic hormones |
| Neurohormones from Neurohypophysis (posterior pituitary) | -Vasopressin (antidiuretic hormone; ADH) -Variety among species: Arginine vasopressin; lysine-vasopressin; arginine vasotocin -Oxytocin |
| Vasopressin | -Release stimulated by dehydration [Either higher osmolarity in the body or blood volume (blood pressure) lower] -Increases production of aquaporin (Particularly in the kidneys: allows us to reabsorb water) |
| Oxytocin | Stimuli for pulsatile release -By stretch of uterus & cervix -By suckling (mammary tissue stimulation) Actions—smooth muscle contraction -Uterine contraction (Positive feedback) -Milk ejection |
| Melanocyte-Stimulating Hormone (MSH) | Hormone of Pars intermedia -animals that camouflage -contrast between light levels -Have extensions containing vesicles filled with melanin -During low light conditions, pigment is central in melanocyte -MSH->distribution of melanin throughout the ce |
| Thyroid-Stimulating Hormone (TSH) | Thyrotropin Triggered by Thyrotropin-releasing hormone (TRH)from hypothalamus -TSH stimulates thyroid to release T3& T4 -Short loop and long loop negative feedback -Increased metabolism |
| Adrenocorticotropic Hormone (ACTH) | Triggered by release of Corticotropin-releasing hormone (CRH)from hypothalamus -stimulates adrenal gland to release glucocorticoids, which increase blood glucose level -Stress response -Long loop negative feedback |
| 1-Growth Hormone (GH) | Triggered by release of growth hormone-releasing hormone (GHRH)from hypothalamus -Occurs most during deep sleep |
| 2-Growth Hormone (GH) | Triggered by release of Growth horm-inhibiting horm (GHIH)from hypothal -GH stim. liver to release IGF-1 (Insulin-like growth factor 1) ->Growth ->Increase blood gluco (growth requires increased met) ->No neg feedback from the body…reg by the nerv sy |
| Prolactin | -Unless suppressed, cells will always be releasing prolactin -Release inhibited by dopamine from hypothalamus -Stimulates milk production in female mammals |
| Follicle Stimulating Hormone (FSH) and Lutenizing Hormone (LH) | Release triggered by release of Gonadotropin-Releasing Hormone(GnRH)from hypothalamus -Targets cells to release both FSH and LH -Found in ALL sexually releasing species -Stimulate cells within the gonads (LH-Leydig Cells, FSH-sertoli cells) |
| Thyrotropin-Releasing Hormone (TRH) | Released by the hypothalamus, triggers the release of Thyroid-Stimulating Hormone(TSH) from the anterior pituitary |
| Corticotropin-releasing hormone (CRH) | Released by the hypothalamus, triggers the release of Adrenocorticotropic Hormone (ACTH) from the anterior pituitary |
| Growth-Hormone Releasing Hormone (GHRH) | Released from the hypothalamus (during sleep) |
| Growth-Hormone Inhibiting Hormone (GHIH) | |
| Dopamine | Released from the hypothalamus to inhibit prolactin |
| Gonadotropin-Releasing Hormone (GnRH) | Released by the hypothalamus -Targets cells to release both Follicle-Stimulating Hormone (FSH) and Lutenizing Hormone (LH) • Found in ALL sexually releasing species • Stimulate cells within the gonads |
| Thyroid Gland Structure | Follicle (Thyroglobulin)lined by follicular cells. Parafollicular cells between follicular cells. |
| Thyroglobulin | Protein stored in the follicle to store thyroid hormones (T3 and T4) |
| Thyroid Hormones | Hypothalamus releases thyrotropin releasing hormone (TRH), which triggers the anterior pituitary to release thyroid-stimulating hormone (TSH), which causes the increase of making and breaking of thyroglobulin + releases T3&T4 |
| T3 (active hormone)& T4 | Thyroid hormones triggered by thyroid stimulating hormone (TSH) release from anterior pituitary. -Increases BMR:protein synthesis, favors glucose/fat use -Enables cell division:esp. neurons (produced at a VERY high rate in development) -Necessary for |
| Hypothyroidism | Damage to pituitary (no TSH prod) or thyroid (TSH released, but thyroid ignores)=Reduced T3& -Lack iodine=no neg feedbk=growth (by TSH) Weak, tired, cold, weight gain Cretinism [Fetus not exposed to adequate=mental retardation (lack of neuron productio |
| Hyperthyroidism | -Pituitary tumor=high TSH=high T3&T4=thyroid growth -Thyroid tumor=Low TSH (high neg feedback)=high T3&T4 due to self-stim of tumor -high T3&T4 -hyperactive, insomnia, hot, weight loss |
| Thyroid: Parafollicular Cells | Calcitonin: -Released when blood Ca2+ is high -Stimulates uptake of Ca2+ into bone -Acute regulation according to blood calcium levels |
| Calcitonin | Released from parafollicular cells when blood calcium is high to stimulate uptake of Ca2+ into the bone |
| Parathyroid Hormone | -Released when blood Ca2+ is low -Stimulates reabsorption of Ca2+ from bone -Neurons, muscle -Enables Ca2+ absorption from small intestine -Works with vitamin D |
| Medulla | -Sympathetic nervous system -Epinephrine -Norepinephrine -Increased blood vessel tone (more constriction raises blood pressure) -Increased HR/contractility -Liver releases glucose (energy) |
| Glucocorticoid | Steroid hormone (cortisol-human, cortisone-rat) -neg feedback w/hypothalamus Released before waking (circadian rhythm) and under stress Increases blood glucose (targets liver) |
| Aldosterone | -Interacts with kidneys-independent of hypothalamus and pituitary -Steroid Hormone -Release:Low blood pressure/low blood volume (similar to vasopressin/ADH), Hyposmolarity -Sodium reabsorption (kidneys) -Water may follow Na |
| Pancreas | Dual Endocrine / Exocrine -Glucagon (Alpha cells) ->Stimulus: low glucose ->Liver releases glucose -Insulin (Beta cells) ->Stimulus: high glucose ->Cells take up glucose |
| Sexual Reproduction: Advantages | -genetic recombination -increased diversity |
| Sexual Reproduction: Disadvantages | -Requires energy, time investment -More vulnerable to predation -Mating, birthing, caring -STDs -Only pass down half of chromosomes |
| Temperature-Dependent Sexual Differentiation | -Correlates with size dimorphism of adults -Larger sex produced under higher temperatures |
| Sexual Differentiation: Social Cues | Unidirectional (sequentially hermaphroditic) |
| Protogyny | "First Female" -if the male is removed, a dominant female will become male -change of ovaries into testes precedes hormonal change |
| Protoandry | "First Male" -eggs require energy, so size threshold must be reached (body mass is required to produce eggs) |
| Bird Sex Chromosomes | WZ (female) WW (male) |
| Jost Paradigm | Development of mammalian embryos -Orderly development of sexual differentiation 1.Genetic sex first 2.Gonadalsex (influenced by genetic sex) 3.Phenotypic sex (influenced by gonadal sex) -Outer/inner qualities -Male vs. female: fetal development |
| Mammalian Sex Differentiation | Genetic sex(XY vs. XX)->Gonadal->Phenotypic Gonad->(SRY)->testes (MIH and testosterone released)->formation of Wolffian Duct, testost. stim. fusion, forms penis Gonad->(no SRY)->ovaries->formation of Mullerian Duct-> no fusion (no testosterone)=clit&lab |
| Internal Reproductive Tracts | Wolffian Duct:needs rescuing (requires testosterone) Mullerian Duct:needs degrading (this requires MIH) |
| Wolffian Duct | Male Reproductive Tract |
| Mullerian Duct | Female Reproductive Tract |
| Male Phenotype | Internal: Wolffian Duct rescued (testosterone), Mullerian Duct reabsorbed (MIH) External: fusion (stim. by testosterone)=penis, testes descend to scrotal sac |
| Female Phenotype | Internal:Wolffian Duct reabsorbed (no testosterone), Mullerian Duct develops (no MIH) External:no testosterone=no fusion=clitoris,labia, vagina |
| Vas Deferens | transports sperm from epididymis |
| Epididymis | Site of sperm maturation |
| Urethra | Tract for exit of urine and semen from the body |
| Seminal Vesicle | Carries semen from testicles -testosterone-sensitive |
| Prostate Gland | -Surrounds urethra -Gives a thinner alkaline fluid -Problem for males: slowly grows throughout the male’s lifetime ->Tissues grows outward and inward (toward urethra) ->Emptying bladder becomes difficult |
| Bulbourethra Glands | Release thin mucuous ahead of the semen to line the inside of the urethra to trap particles from the urine |
| Erection | Rigidity of the penis that enables copulation -parasympathetic: releases nitric oxide->arteries surrounding sinuses to dilate, veins are crushed->more blood comes in, prevent blood leaving the sinus |
| Ejaculation | Projection of semen from the male reproductive tract -sympathetic |
| Baculum (Os penis) | Bone (usually retractable) that aids in penis rigidity |
| Turner Syndrome | X(0) – they only have one X chromosome – -female, and have a small stature; infertile |
| Kleinfelter's Syndrome | XXY -Male, lengthened limbs |
| Complete Androgen Insensitivity Syndrome | Do not have a testosterone rec. -produce test., unable to detect it -XY chromosome->SRY gene=testes form->MIH and test. released (no preservation of Wolffian duct) -Lack of fusion (penis) due to lack of test. reception -puberty:breasts, |
| Impotence | Inability to have an erection, due to physiological or psychological problems |
| Semen | Sympathetic reflex release: Highly alkaline fluid (for protection from acidity of urine and female reproductive tract) -contains fructose for "feeding" sperm |
| Seminiferous Tubules | Stem cells multiply, as cells differentiate, they move toward the center lumen -Move to epididymis (maturation of sperm) |
| Sperm Cell Structure | Head, nucleus (condensed chromosomes), ATP for movement (from fructose), Acrosome (enzymes for breaking down protein barrier around the egg) |
| Acrosome | Organelle in a sperm cells that contains enzymes for breaking down the protein barrier around the egg |
| Leydig Cell | Interstitial cell stimulated by LH to release testosterone |
| Sertoli Cell | Nurse cell that makes contact with multiple developing sperm and stem cells. -forms blood-testes barrier (protects sperm cell from immune system that recognizes it as foreign) -stim. by FSH/test. to guide sperm cell differentiation |
| Androgenic Steroid Abuse | High neg feedbk to GnRH->NO LH -> no self-prod testosterone/NO FSH to sertoli cells (shrink, spermatogenensis slows=temp. infert, immune system=permt infert) -Blood chol increase (chol not being used)->heart contraction more difficult->heart disease |
| Decremental | To lessen or fade over time. Graded potentials are decremental, but action potentials are not |
| Gray Matter | Cell bodies, dendrites, & synapses -Organized as nuclei; brain cortex |
| White Matter | Myelinated axons (speeds up the signal)- oligodendrocytes -Organized as neural tracts (in the brain) or nerves (in the body) |
Created by:
Medgbert
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