Lecture test #2

Steroid

* derived from cholesterol* 1. produced in Smooth ER of adrenal cortex, gonads, and placenta 2. synthesized as they are needed 3. LIPID->must bind to protein carrier molecules in the blood (globulin and albumin) 4. Binding to protein extends their half life 5. Lipid soluble-they diffuse through CM, bind to intracellular receptors, turn genes on or off, affecting protein synthesis 6. steroid pathways are slower than peptide hormones 7. can also bind to membrane receptors and initiate rapid response

Which subdivision of PNS controls glands, as well as smooth and cardiac muscle function? How do the sympathetic and parasympathetic divisions differ in function?

*Autonomic nervous system* 1. Visceral sensory neurons from inter-receptors in internal organs and blood vessels convey signals to CNS 2. Visceral Motor neurons Convey impulses from the CNS, to smooth muscle, cardiac muscle, and glands a. Sympathtetic: flight or fight b. Parasympathetic: rest and digest

- What is a hormone? What is meant by a target tissue for a hormone? Why don't all tissues respond to all hormones passing by them in the blood?

*Hormones*: chemical messengers released by a cell or tissue into the bloodstream, in which they travel to target cells Target tissues: must have receptors for particular hormone ABILITY OF THE TARGET TISSUE TO RESPOND DEPENDS ON THE ABILITY OF THE HORMONE TO BIND WITH SPECIFIC RECEPTORS (PROTEINS) ON CELLS PLASMA MEMBRANE OR WITHIN THE CELL.

- In addition to hormonal hypersecretion or hyposecretion, what other problems can cause abnormal target tissue responsiveness?

*Hypersecretion* exaggerates hormones effect Causes of Excess hormones secretion-include tumors on endocrine glands Ex: Excess GH in children can cause gigantism/ Acromegaly in adult abnormal plasma concentrations of a hormone resulting from inappropriate rates of secretion. Hypercortisolism-cushing's syndrome Hyperthyrodism T3-Graves disease, Goiter Excess of Insulin like growth factors=Prada willi syndrom

In what specific area of the retina is incoming light focused? Why is vision sharper in the light than in the dark?

*Lens* *Due to Photochemical reaction of retina* 1. In the dark, retinal has a bent shape (Cis-retinal) 2. Light converts Cis- retinal to straight shape called (Trans-retinal), has violet color 3. the conversion of cis-retinal to trans-retinal leads to the production of a visual nerve signal in the rods and cons 4. Trans-retinal lsoes its color quickly (bleaching) then is transported to the epithelium, reconverted to cis-retinal, transported back to the Opsin in the photoreceptros

- What area of the retina lacks photoreceptors?

*Optic Disc* The blind spot. Area in the retina that lacks photoreceptors and the optic nerve exits the eye.

- In terms of endocrine pathologies, how do primary and secondary pathologies differ? Primary-problem within that gland Secondary-dysfunction in gland producing trophic hormones No ACTH from Pituitary gland-> No cortisol

*Primary* If pathology (deficiency or excess) arises in the lost Endocrine gland in a reflex Ex. damaged adrenal gland produces excess cortisol-> primary hypersecretion *Secondary* If dysfunction occurs in a tissue producing Trophic hormones Ex. If pituitary ACTH secretion diminishes->No Cortisol from Adrenal gland

Why is it necessary to maintain calcium homeostasis in the bloodstream? (For what functions is calcium needed in the body?) In order to prevent hypercalcemia or hypocalcemia What occurs in hypo- and hypercalcemia?

*Principle of mass balance* Total body calcium=intake-output 1. Ca intake is from the diet and uptake from the small intestine 2. Ca output occurs mainly in the kidney and feces 3. total body Ca is divided among three compartments a. Extracellular fluid/plasma: Ca is about 2.5mM b. Intracellular Ca-free in the cytosol, mitochondria, and in the sarcoplasmic reticulum of muscle cells 3. Extracellular matrix in bones-the largest Ca reservoir (2.5lbs)

- What specific ear structures allow us to sense head rotation? What mechanism is involved? Semicircular ducts -contain Crista Ampullaris a. hair cells b. capula c. What happen when head turns d. hair cells-> vestibular nerve-> cochlear nerve-> brain=head rotation

*Semicircular ducts* 1. expanded end of the ducts where they join the vestibule, contains the 2. *crista ampullaris*, which house the receptor hair cells, epithelial support cells, and capula a. Hair cells: stereocilia & kinocillium embedded in b. Capula-gelatinous membrane that extends from the crista to the roof of the ampulla c. when the head turns, the duct rotates, but endolymph lags behind and pushes the capula, which bends the streocilia and stimulates the hair cell d. the hair cells transmit nerve impulses to the vestibular nerve, which joins the cochlear nerve to send the impulses to the brain, which interprets the head rotation

- Which subdivision of the PNS controls sensory input and skeletal muscle function?

*Somatic (Voluntary) nervous system-SNS 1. Somatic sensory neurons convey impulses from the skin, muscle, bones, and joints to the CNS 2. Somatic motor neurons conduct impulses from the CNS to skeletal muscle tissues

How is a nerve impulse transmitted from a neuron to its effector?

*Specificity of neural communication* 1. signal molecules secreted by neurons 2. target cell receptor for the chemical 3. synaps-the connections between neurons and their effectors

- What allows us to see different colors? What causes color blindness?

*Three types of cones* 1. Red: Photopsins absorb orange light wavelengths (558nm) 2. Green: Photopsins absorb green light wavelengths (531nm) 3. Blue: Photopsins absorb blue light wavelengths (420nm) *Perception of different colors is based on a mixture of nerve signals from three cone shape* *Color blindness*-hereditary condition in which a person lacks one or more photopsins in their conses, resulting in the inability to see certain colors

What specific ear structures allow us to sense linear & vertical acceleration? What mechanism is involved? 1. Macular 2. Each hair cell has (2) 3. Otoliths 4. When the head moves 5. Brain compares input

*Utricle & Saccule* 1. a patch of sensory hair cells surrounded by epithelial support cells 2. each hair cell has many stereosilia and one kinocilium embedded in an otolithic membrane 3. the membrane also contains tiny calcium carbonate *stones* 4. when the head moves, the otolithic membrane slides with gravity and bends the hair cells, which send a nerve impulse to the vestibular nerve 5. the brain compares input from the utricle & saccule to determine head orientation, respect to linear and vertical acceleration

- Trace the pathway of sound waves from the outer ear to the cochlea, and through the neural pathway to the cerebrum's auditory cortex.

*Vibration of the cochlear basilar membrane* Cochlear hair cells(stereocilia in the tectorial membrane)-> Bipolar neurons(in the spiral ganglion that curves around modiolus)-> Vestibulocochlear nerve(CN8)-> Pons(In the brain stem)-> Inferior colliculi(auditory reflex center) in the mid brain-> Thalamus(medial geniculate nuclei-> Auditory cortex (temporal lobe) =Interpreted as sound

- How is the eye's focus changed? What structures are involved? Why is it more difficult for the eye to change focus as we age?

*by changing lens shape* Light from distant source=approach eyes as parallel lays/focused on retina-no change in lens convexity is necessary for it to focus properly on the retina *Emmetropia=relaxed stage of eyes* Light from the closer source=*diverge* convexity of the eye must increase to to make close vision-* Cilliary muscle contraction required to increase tenstion of of the ciliary zonule attached to the lens and allowing the elastic lens to bulge. Its more difficult for the eye to change focus-> due to loss of lens accomodation causing by gradual lessening of lens elasticity as we age.

- Compare the absolute and relative refractory periods of a neuron. *refractory period* (Period of neural insensitivity to re-stimulation) 1. absolute refractory period (Start->End of AP, Na channels are still open) 2. relative refractory period (Until Hyperpolarization ends, K channels are still open but Na channels are closed-Strong stimuli can trigger another AP)

*period of neuronal insensitivity to restimulation during/ after the action potential* 2. occurs from start to end of the action potential, which the Na+ channels are still open a. during this time-the neuron can't be further stimulated regardless of the stimulus strength b. ensure 1 way-transmission of the action potential 3. lasts until hyperpolarization ends, when K channel are still open, but Na channels are closed a. during this time-an exceptionally strong stimulus can trigger another action potential

- What are the three parts of a synapse? What are the two types of synapses? *Synapses*

*place where a neuron meets its effector (another neuron, muscle, or gland cell)* a. presynaptic neuron axon terminal b. synaptic cleft-minute gap btw. presynaptic axon and c. post-synaptic cell membrane

- How and by what structures is incoming light through the pupil regulated? 1. Pupillary constriction-Circular smooth muscle Parasympathetic nerves 2. Pupillary dilator-Myoepithelial cells Sympathetic nerves

*two contractile element in the Iris* 1. Pupillary constriction a. circular smooth muscle around pupil b. *Parasympathetic nerves* narrow the pupil in bright light conditions, and when Eye focus changes (focusing on closer things) c. Both pupils constrict-when even one eye is exposed to light-*photopupillary reflexes* 2. Pupillary dilator a. *Myoepithelial cells* radially arranged pupil b. *Sympathetic nerves* widen the pupil in low light. stressful conditions

- What is the resting membrane potential in a neuron? What is the main ion responsible for it? Membrane potential to the ions 1. Resting neuron is more permeable to ____ 2.major ion to membrane potential? 3. resting membrane potential is ___mV

-70mV, K is responsible for resting membrane potential. 1. resting neuron membrane is more permeable to K than Na, or Ca (K leaks out slowly out of K ion channel) 2. K is the major ion that contribues to the resting membrane potential 3. In the ave. neuron, the resting membrane potential is about -70mV

- Where is the reticular activating system (RAS) located, and what are its functions?-*Conscious attention* Reticular activating system 1. somatic motor control 2. cardiovascular control 3. pain modulation 4. sleep and conscioueness

-a functional network in brainstem that determines what sensory information comes to our conscious attention 1. helps the cerebellum to maintain muscle tone and produce coordinated contractions of skeletal muscle 2. includes the cardiac center and vasomotor center of the MO 3. Origin of descending analgesic pathways of the reticulospinal tracts 4. projection tracts to the thalamus and cerebral cortex; act as a gatekeeper that decides _____comes to our conscious attention

- Describe the 3 main functions of the nervous system.

1 a sensory function, 2. an interpretative function 3. motor function. 1. sensory receptors within and near the body's surface response to stimuli and send nerve impluses to the CNS 2. CNS receives, processes, and interprets the sensory input, the decides what to do with 3. the CNS-sends nerve impulses to effector organs (muscle and glands) in response to the sensory input

- Trace the pathway of light from cornea to retina, and neural impulses from photoreceptors to the cerebrum's visual cortex. LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway.

1. *Photoreceptors* transmits visual impulses to 2. *Bipolar cells*: transmit impulses to 3. *ganglion cells*, axons of which forms 4. *optic nerve* (CN2) which cross over optic at 5. *Optic chiasma* then enter brain through 6. *Optic tracks* nerve fibers synaps with neurons in the 7. *thalamus* 8. lateral geniculate neurons form the *Optic radiation* of nerve fibers->transmits impulses to 9. *Visual cortex* in the occipital lobes of the brain for interpretation

Sensory transduction in retina Two major layers

1. *Pigment layer*: posterior layer; composed of dark cuboidal epitherlial cells, absorbs light that is not absorbed by receptor cells in the 2. Neural layer: inner layer near the vitreous humor, coposed of three main layers of neural cells (pigment layer to viterous humor) *Photoreceptors* cells-first to receive incoming light rays 1. rods: cylinderical cells containing rhodopsin pigment that absorbs light, responsible for night vision in black & white 2. Cones-cone shaped cells, that include red, green, and blue photoreceptors and fucntion in bright lights and areresponsible for color vision 3. Rods and cones receive and transmit nerve impulses to *Bipolar cells*: neuron dendrites recieve nerve impulses from rods and cones, then transmit the impulses along axons to *Ganglion cells*: neuron dendrites receive nerve impulses from bipolar cells; axons converge to form the optic nerve that exits the back of the eye and carries impulses to the brain

- What are the main functions of the thalamus? (Hint: sensory relay station)

1. *serves as relay stations for nearly all sensory impulses to appropriate regions of cerebral cortex* 2. receives input from the regions of the cerebrum involved in motor control 3. interconnected with the limbic system, involved in emotional and memory functions 4. arousal, eye movements, taste, smell, hearings, equilibrium, and somatosensory input

What are the 6 major classes of neurotransmitters? Give examples of each, and their effects (especially ACh and catecholamines). 1. Ach 2. AA 3. Amine 4. Polypeptides 5. Purines 6. Gases 7. Lipids

1. Acethylcoholine-PNS a. neurons that secrete Ach, and Ach receptors are called *cholinergic* b. excitory in skeletal muscle/inhibitory in cardiac muscle 2. Amino acids a. Excitory AA in CNS: Glutamate and aspartate b. Inhibitory AA in CNS: Glycine and GABA 3. AA derived Amine (Mostly made from *tyrosin*) Epinephrine, NE, Dopamine a. neurons that secrete NE & NE receptors are *Adrenalgic* NE is main neurotransmitters of sympathetic NS. b. Catecholamine: PNS, excitory in cardiac muscle/ Excitory or Inihibitory in smooth and gland c. Dopamine: inhibits involuntary skeletal muscle movements; lack of dopamine which leads to parkinson's disease d. *Indolamine* include 1. seratonine: made from tryptophan in the CNS is involved in sleep, alertness, thermo-regulation and Mood 2. histamine-vasodilator 4. Polypeptides: a. substance P-involved in some pain pathways b. Opoid peptide (endorphins & enkaphalins)-analgesic (suppress pain)

Neuroglial cells of the CNS (4)

1. Astrocytes 2. Oligodendrocytes 3. Microglial cells 4. Ependymal cells

What are the three main groups of neurohormones? What organs (glands) secrete these hormones?

1. Catecolamine made by adrenal medulla 2. Posterior pituitary hormones synthesized in hypothalamus 3. Trophic hormones from hypothalamus that act on anterior pituitary

Cones (Macula Lutea) Rods (Pheripheral retina)

1. Cones are found mainly in the retina's *macula lutea* and are the only photoreceptors found in the fovea centralis a. Each cone synapses with *one bipolar cell* which synaps with *one ganglionic cell* that sends the image to the brain b. The one to one relationship between the cells produce *sharp color image in bright light* 2. Rods are scatter through the *peripheral retina* a. several rods to one ganglionic cell b. results in a lost of clear image in dim light

- What are the main functions of the hypothalamus? Why is it called the master of the ANS?

1. Controls of ANS-Controls and integrates and ANS, which regulates contraction of smooth muscle, cardiac muscle and glandular secretions 2. Control of pituitary gland via hypothalamic hormones 3. Regulation of emotinos & Behaviors rage, aggression, pain , pleasure, and sexual arousal 4. Regulation of hunger, thirst & satiety 5. Sleep control: superchiasmic nucleus establishes 24 hour sleep patterns 6.Memory- mamillary bodies are part of a signaling pathway from the hippocampus (a memory center) to the thalamus

- What four structures/substances inside the eye refract incoming light? Refraction of light through the eyes

1. Cornea: clear, convex structure on the anterior eye; most light refraction occurs here 2. Aqueous humor: watery fluid in the anterior segment 3. Lens: clear, bioconvex structure bet. the aqueous and vitreous humor; fine tunes (focuses) the incoming image 4. Vitreous humor: clear, gel-like material in the posterior segment a. Astigmatism: involves an uneven surface on the lens and or cornea, which causess light to bend unevenly, causing blurred vision b. Glucoma: is an elevated pressure within the eye-often caused by a blockage in the canal of schlemm, so aqueous humor builds up

- What are the three layers of connective tissue around the brain and spinal cord? What happens if bleeding occurs in the spaces between these layers? What is an infection of the tissues called? Arachoid mater a. subdural space b. subarachoid space-CSF c. subdural or subarachnoid hermatoma

1. Dura meter thickest layer, associated with veins that drain blood through vessels and sinuses 2. Arachoid mater: thin, web-like membrane a. between dura and arachoid matter b. between the arachonoid and pia matter, contain CSF c. breeding into the above spaces due to head trauma, which can result in coma or death 3. Pia Mater thin, vascular membrane that adhere to the surface of the brain and spinal cord *Meningitis*

Response in their reflex system

1. Endocrine system: response is *hormone* 2. Nervous system: Response is *Neurohormones* or *electrical signals* 3. Simple reflux pathways-> resopnse usually serves as negative feed back that turns off the reflex. Ex. Rise in blood glucose levels triggers *Insulin* releases from pancreatic cells; Insulin stimulates uptake of glucose by target cells, which terminates insulin secretion

How is the release of growth hormone regulated? What are the target organs of GH? What hormone is released by the liver in response to GH, and what are its effects?

1. GHRH and GHIH from Hypothalamus promote or inhibits the release of GH (Ant. Pituitary gland) 2. GH targers Liver, Muscle, bone, and cartilage (Most tissues) Liver secrets *Insulin-like-Growth Factors* which act with GH to stimulate bone, cartilage, and muscle growth-> Energy and AA into protein synthesis, Fat breakdown and liver glucose increases

Mechanism for Graded Potentials Graded potentials=strength of stimulus that intiates them 1. graded potentials 2. neurons can be stimulated by (5) 3. when stimulated-neuronal ions channels open/close 4. resulting change in membrane potentials is _____s a. weak stimulus b. strong stimulus

1. Graded potential are depolarization or hyperpolarizations that usually occurs in *dendrites or the cell body* 2. Neurons are stimulated by chemicals, light, heat, voltage, or mechanical distortion of CM 3. Stimulated-neurons open ion gated channels-Causing ions to enter or leave the ions 4. Change in membrane potential=strength of the initial stimulus a. Weak stimulus=weak graded potential that will not travel far (feather) b. Strong stimulus=strong graded potential that may be converted to an action potential

Calcium in the blood plasma is crucial to life process

1. Intracelllular 2nd messenger signaling 2. Exocytosis of materials from cells 3. Muscle contraction 4. Blood coagulation 4. Neural function (Brain/spinal cord)

- Compare and contrast light and dark adaptation in the eyes.

1. Light adaptation-occurs when you go from darkness into light a. Pupils constrict to reduce incoming light b. Rods bleach quickly, and cones take over in about 5-10 min 2. Dark Adaptation: when you go from light to dark a. pupils dialate to admit more light into the eye b. rhodopsin regenerate faster than it bleaches; rods reach maximum sensitivity in about 20-30min

Nervous system

1. Neurons can stimulate Endocrine glands (Adrenal medulla) to release hormones 2. Neurons take neuro-hormones into the bloodstream (Hypothalamus)

What three hormones regulate blood plasma calcium levels,and how do they do so? 1. PTH 2. Vitamin D (Calcitrol) 3. Calcitonin Where is the majority of calcium found in the body? Bones

1. PTH Parathyroid gland sense declining Ca levels and release PTH, which travels to a. bones: osteoclasts are stimulated to reabsorbe Ca+ b. kidney: Ca is reaborbed c. Small intestine: Ca uptake is incrased via PTH influences on vit. D(Calcitriols) 2. Vitamin D (Calcitrol), ingested or made in the skin, liver, and kidney in response to UV radiation a. uptake of Ca from intestine and kidney b. mobilization of Ca out of bones into ECF 3. Calcitonin Thryoid C-cells in response to increasing blood Ca levels, stimulate Ca deposition in the bones *Majority of calcium found in Bones*

Endocrine cells is the *sensor and integration center* Ex. Parathyroid hormones

1. Parathyroid cells monitor blood Ca concentration via G protein-coupled Ca receptors in their cell membrane 2. When Ca bound to the receptors, PTH secretion is inhibited 3. If Blood Ca level declines, fewer receptors are bound, cells release PTH 4. PTH travels to target cells (bones and small intestine) triggers response to release Ca levels

- How does one neuron inhibit the activity of another neuron?

1. Post synaptic Inhibition occurs when one neuron suppresses the effect of another neuron (a neuron that generates IPSPs prevents neurotransmitter release another neurons)

- How is synaptic activity modulated (regulated)? *1. presynaptic moducation* a. Presynaptic inhibition b. presynaptic facilitation 2. Post synaptic modulation

1. Presynaptic moduclation a. occurs when a presynaptic neuron inhibitory neurotransmitters release by a postsynaptic cell b. occurs when the presynaptic neuron excitory neurotransmitter release by postsynaptic cell 2. occurs when a modulatory neuron usually inhibitory synapses with the dendrites or cell body of a postsynaptic cell

1. Seratonine 2. Dopamine. 3. Acetylcoholine 4. Noepeinephrine 5. GABA. 6. Glutamate.

1. Seratonie: made from tryptophan in the CNS is involved in sleep, alertness, thermoregulation and Mood 2. Dopamine: inhibits involuntatry skeletal muscle movements; lack of dopamine which leads to parkinsons disease 3. Acethylcoholine a. neurons that secrete Ach, and Ach receptors b. excitory in skeletal muscle/inhibitory in cardiac muscle 4. neurons that Secretes Noepeinephrine and NE Receptors:Adrenorgic NE, main neurotransmitters of SNS affects neurons involved in heart rate, intestinal activity during stress, dreaming, waking from sleep, emotion, learning, & memory 5. Excitory AA in CNS: Glutamate and aspartate 6. Inhibitory AA in CNS: Glycine and GABA

- What are the basal nuclei (ganglia) and limbic system, and what are their functions? 1. Basal nuclei 2. Limbic System a. Amygdala (emotional brain) b. Hippocampus (memory consolidation)

1. Specialized paired masses of gray matter that arch around the thalamus a. inhibit involuntary motor movement, consists of the *corpus striatum and amygdala nuclei* b.Nuclei receive input from the substantia nigra (in the midbrain) and motor areas of the cerebral cortex and send signals back to both c. Damage to basal nuclei-motor movement dysfunction, found in parkinson's and huntington's diseae 2. a loop of grey matter around the corpus callosum and thalamus; includes the amygdala and hippocampus a. considered to be part of the *emotional brain*, with a role in emotional memories-feelings of pleasure, love, anger, fear, and pain b. memory consolidation, organizing sensory and cognitive experiences into unified long-term memories, which are then stored in the temporal and frontal lobes

Trophic hormones (From anterior pituitary) -affect adrenals, gonad, and Thyroid

1. Stimulated by hypothalamus, anterior pituitary release * trophic hormones* that affect adrenals, gonads, and thyroid a. ACTH: Stimulates adrenal cortex to secrete corticoid steroids b. FSH &LH: gonads to produce sex steroids c. TSH: Thyroid hormone release

- Describe the basic functions of the 7 hormones produced by the anterior pituitary gland. How do the trophic and nontrophic hormones differ? Trophic hormones - *stimulate other glands* to release hormones to stimulate target cells Non-tropic hormones are hormones that directly stimulate target cells

1. TSH: Stimulate thyroid glands to release thyroid hormones , regulate metabolism 2. ACTH: Stimulate adrenal cortex to release secrets *cortisol* 3. GH: Growth and metabolism, Stimulate hormones secretion by the liver 4. FSH: stimulates the maturation of ovarian follicles/ Sperm production (Gonad) 5. LH: produce sex hormones from gonad *Non-Tropic hormones* 1. PRL: Stimulates breast tissue to produce milk 2. MSH: Melatonocytes; distribution of melanin granules

- Describe the basic functions of the two neurohormones produced in the hypothalamus and stored in the posterior pituitary gland until needed.

1. Vasopression-water balance in the body 2. Oxytocin-uterine contractions during childbirth, milk ejection during breast-feeding

Mechanism for Graded Potentials 1. Chemical binding 2. Ligand gated sodium channels 3. Na influx-> depolarization 4. Na ion-> axon hillock 5. graded potential

1. a chemical binds to receptor in the neuron PM (Dendrites or cell body) 2. ligand-gated sodium channels that open/allow Na to diffuse into neuron 3. Na influx cause neuron internal negative charge to become more positive-depolarized-voltage moves from -70 to above zero. 4. incoming Na ion produce a current that travels to the cell body, then to the cells' trigger zone (Axon hillock)- 5. the limited short range change in voltage in the neuron is called graded potential 6. if the graded potential depolarizes the membranes - to the threshold voltage (-55mV), the voltage-gated Na channels are open, and an action potential is initiated in neurons

- What ions are involved in the establishment of a neuron's membrane potential? In what relative concentrations are these ions found inside and outside of the cell? Ion concentration gradients in a resting position 1. Positive charge outside of neuron 2. negative charge inside of neuron 3. Membrane's potential voltage

1. a higher concentration of Na, Cl, and Ca in the ECF, results in a more positive charge outside of the neuron 2. a higher concentration of anions and K in the ICF resulting more negative charge inside the neuron 3. .the difference in charge is the membrane's potential voltage

Duration of stimulus 1. Tonic receptors 2. Phasic receptors

1. adapt slowly and generate impulses continually (Nociceptors, prioprioceptors) 2. Generate burst of impulses when first stimulated, *adapt rapidly* to a stimulus, and stop even if stimulus continues (touch, pressure, and smell receptors)

- Compare and contrast graded (local) potentials with action potentials. What is the mechanism for each? In what ways are they similar? How do they differ? Action potential are differ. from graded potentials 1. same voltage 2. do not diminish in strength 3. all or none

1. all action potentials have same voltage 2. action potentials do not diminish in strength as they travel 3. action potentials all or none they will only be generated if threshhold is reached in the neuron's trigger zone.

What specific inner ear structures are responsible for hearing? https://www.youtube.com/watch?v=PeTriGTENoc 1. Stapes movement 2. Perilymph 3. Vestibular membrane 4. Endolymph movement 5. Basilar movement

1. causes waves in the scala vestibuli perilymph 2. Stapes movement pushes the vestibular membrane down 3. Perilymph pushes on Endolymph in the cochlear duct 4. Vestitular membrane pushes the basilar membrane down & up, bending the *hair cells streocilia in the tectorial membrane, sending auditory nerve impulses to the cochlear nerve 5. Basilar membrane pushes on the perilymph of the scala tympani, causing the round window membrane to bulge out and in

- What 4 components are needed to perceive a sensation? 1. Stimulus 2. Receptor 3. Conduction 4. Interpretation

1. chemical, mechanical, temperature, light-to initiate a nervous system response 2. sensory neuron dendrites or specialized epithelial cells-transducer that converts the transducer that converts the stimulus to a nerve impulse 3. of the nerve impulse from the receptor to the brain, via sensory (ascending) nerve tracts In the spinal cord 4. of the perception in the *brain's cerebral cortex*, after passing through the medulla, pons & thalamus

- Name 5 types of sensory receptors. 1. Chemoreceptors 2. Thermoreceptors 3. Nocireceptor 4. Mechanoreceptor 5. Photoreceptor

1. chemicals-tongues, nose, blood vessels 2. heat and cold; found in skin 3. pain and itch; found throughout the body, except in the brain 4. physical deformation of plasma membrane caused by touch, pressure, stretch, tension, or vibration; found in skin, viscera, and joints (Separate slide) 5. Eye responds to light

- What are the three types of nerve tracts in the cerebrum? 1. Association fibers-Same hemispheres 2. commisural fibers-two hemispheres 3. projection fibers-connect to tracks of spinal/brain cord

1. conduct impulses bet. neurons within a hemisphere (fibers bet. broca's & 2. connects the neurons & gyri of one hemisphere with those of the aother 3. form the ascending and descending tracks of the brain and spinal cord Gray matter of cerebrum

- How is calcium involved in the release of a neurotransmitter from an axon terminal? Ca is the signal for neurotransmitter to be released from axon terminal (Pre-synaptic cell) 1. axon terminal 2. neurotransmitters 3. neuro-toxins

1. contain many mitochondria and synaptic vesciles that house neurotransmitter chemicals 2. Neurotransmitters are released from the presynaptic axon terminal to the post synaptic cell membrane a. an action potential depolarizes the axon terminals b. depolarization opens *voltage gated ca channels*, and ca enters the axon terminal c. calcium binds to intracellular regulatory protein and initiate exocytosis d. neurotransmitter released from the vesicles diffuse across the synaptic cleft and bind to ligand-gated ion channel on the post synaptic cell membrane e. a response(graded potential) is initiated in the postsynaptic cell 3. can inhibit certain proteins (voltage gated ca ion channels) in the neuron's exocytotic apprattus, thus blocking nerve transmission.

- What are catecholamines, and where are they produced?

1. epinephrine (adrenaline) 2. norepinephrine (noradrenaline), 3. dopamine *adrenal medulla* Enhance sympathetic NS: fight-or-flight response .

- What are the 3 main functional areas of the cerebral cortex? 1. motor areas 2. sensory areas 3. association areas

1. frontal lobe that control voluntary motor functions 2. parietal lobes that provide for awareness of sensations 3. integrate information from different lobes that provide for appropriate actions (allow us to smella rose, name it and picture it)

Types of neurons 1. pseudo-unipolar 2. bipolar 3. multipolar 4. inter-neuron-Only CNS

1. has one process extending from cell body, dendrites located at the distal tip of axon- monitors sensory stimuli (touch or pain) 2. one main dendrite, one axon-rate, found on retina, inner ear, olfactory area of brain-sensory functions 3. several dendrites and one axon- motor neurons found in brain & spinal cord 4. multi-polar neurons found only in the CNS-not purely sensory or motor, conduct impulses to other neurons

- How do myelination and axon diameter affect nerve impulse transmission speed? Larger neurons/with myelinated axons conduct action potentials faster 1. Neurons with larger diameter 2. Unmylienated axons 3. Myelinated axons

1. have decreased resistance to electrical current flow, faster action potentials 2. voltage gated Na channels along their whole length from axon hillock to axon terminal-like a row of Dominos falling over 3. have majority of their voltage gated Na channels in the Node of Ranvier between the myeline sheaths a. Na ions diffuse/inside of the Membrane between nodes, then open the Voltage gated Na channels at the nodes to propagate the action potentials (saltatory conduction) b. the result is faster nerve conduction than in unmyelinated axons

Compare and contrast general ( somatic) and special senses. 1. General senses 2. Special senses

1. have receptors throughout the skin, muscles, tendons, joint capsules, and viscera (Internal organs) 2. a. are limited to head and innervated by cranial nerves b. vision, hearing, equilibrium, taste, and smell

- What three types of gated-ion channels control neuronal ion permeability, and how does each work? 1. Mechanically gated 2. chemically gated (Ligand) 3. voltage gated

1. in sensory neurons open due to pressure or stress, Calcium ion channel 2. open response to ligand-neurotransmitter binding, Sodium/Pottasium gated channel 3. response to changes in membrane voltage

- How is neurotransmitter activity terminated (especially ACh & NE)? 1. Ach-Broken down by Acetylcholinesterease 2. Norepinephrine (Ne)-broken by Mono amine oxidase 3. Amine, polypeptides, and amino acid neurotransmitters-move into blood/ or back into presynaptic axon

1. is broken down by acetylcholinesterase (Ache), then choiline is actively transported back into the presynaptic axon to make more Ach 2. is actively transported back into the presynpatic axon, to be used again or broken down by monoamine oxidase. 3. Move into the Blood or are actively transported back into the presynaptic axon to be metabolized or used ag

- What are the 4 major regions of the brain, and the components of each region. 1. cerebrum 2. diencephalon (4) 3. brain stem (3) 4. cerebellum

1. largest, superior region, compose of five paired lobes within left/right hemispheres 2. central region consists of the thalamus, hypothalamus, pineal gland, and pituitary glnad 3. extends downward from the diencephalon and consists of the midbrain, pons and medulla oblongata 4. posterior, inferior portion

- Know the CNS disorders mentioned in lecture. 1. cerebral palsy 2. epilepsy 3. concussion 4. stroke 5. alzhemizer's disease

1. muscular incoordination due to damage to the motor areas of the brain during fetal development, cuasesd by measles exposure, drugs, radiation, oxygen deficienty, hydrocephalus (water on the brain) 2. symptoms include massive discharge of neurons (seizures), resulting in convulsions, sensory, and phychic disturbances, and often impaired consciounes 3. brain damage due to blow, often with loss of consciousness, blurred vision, and sometimes short-term amnesia 4. occurs when blood circulation to a brain area is blocked and the brain tissue dies 5. mental dementia caused by the development of B-amyloid proteins plague around degenerated neurons and neurofibrillar tangles within neuron cell bodies

After depolarization, repolarization, and hyperpolarization, what restores the original balance of Na+ and K+ to return the neuron to its resting membrane potential? *Na/K pump* (3 Na out/2 K in) Mechanism of AP 1. Before action potential 2. Stimulus in the neuron cause 3. Enough Na ions enter 4. An action potential 5. votage-gated Na channels 6. Hyperprolarization

1. neuron has a resting potential of -70mV and voltage gated ion channels are closed 2. Stimulus will cause graded potential, which travels toward axon hillock, and generate an action potential based on the strength of the local potential. 3. Enough Na enter, 'Axon hillock* to reach threshold voltage (-55mv) 4. Action potential has been generated, down the axon as more voltage-gated Na channels are open, as the depolarization wave rises to about +30mv 5. Voltage gated Na channels close as voltage gated k channels open, causing K to move out of the neuron-and Repolarzation occurs (voltage moves back toward the resting potential) 6. Hyperpolarizarion: a decrease in membrane voltage slightly below the resting potential (-90mv) often occurs because voltage-gated K channels are slow to close

- In what three ways can glands be stimulated to release their hormones (or neurohormones)? Give examples of each method.

1. other hormones 2. humoral substances 3. nervous system stimulation

- What are the two main types of deafness? What is involved in each type? 1. Conduction deafness 2. Nerve(sensorineural) deafness

1. results from damage to structures that transmit sound vibration to the inner ear 2. results from damage to cochlear hair cells or other nerve tissue involved in hearing

- Why is synaptic activity so susceptible to drugs? What disorders are results of faulty synaptic transmission?

1. synaptic receptors are *exposed to the extracellular fluid*, are more accessible to drugs than intracellular receptors 2. common drugs that act on synaptic activity-caffeine and nicotine(stimulant) and alcohol (a depressant) 3. nervous system disorders related to faulty synaptic transmission include parkinson's , schizophrenia, and depression a. drugs used to treat schizophrenia, anxiety and epilepsy act by influencing activity at the synapses

- What brain structures are included in the diencephalon?

1. thalamus 2. hypothalamus 3. pineal 4. pituitary glands

- What are the main functions of the cerebellum-Skeletal muscle contraction? brain structure 1. main function 2. motor input 3. sensory input from

1. to coordinate skeletal muscle contractions and process sensory impulses from proprioreceptors within muscles, tendons, and joints 2. comes from neurons in the cerebral cortex 3. from receptors for balance and equilibrium in the inner ear

Describe the structure of a typical neuron, the types of neurons, and the main functions of the dendrites, cell body, and axon. 1. dendrites 2. cell body 3. axon

1. treelike extensions from the cell body that receive incoming signals from neighboring cells and conduct them to the Cell body 2. control center of the neuron that contain necleus and other organelles-intergrates incoming signals and sends out a response via the Axon 3. single process extending from the cell body-conduct nerve impulses from the neuron to another neuron or to an effector (muscle or gland).

How does the CNS differentiate between the different types of incoming sensory information? 1. Sensory modality (Signal with specific sensation) 2. Stimulus location (specific region of cerebral cortex) 3. Stimulus intensity (numbers of receptors acctivated/frequency) 4. Duration receptors (duration of AP)

1. which types of sensory neurons are activated; the brain associates a signal from a particular type of receptor with a specific sensation 2. coded by different types of sensory neurons sending their impulses through ascending tracks to specific regions of cerebral cortex. 3. coded by the number of receptors that are activated and by the frequency of their action potential 4. coded by the duration of AP is a sensory neuron

- What are the special metabolic requirements of nervous tissue? What two substances does the brain require in large quantities? How does the brain respond to hyper- and hypoglycemia? 1. hyperglycemia (High blood glucose) 2. hypoglycemia (Low blood glucose)

2% of body mass, but recieves 15% of blood supply and 20% of Body's oxygen and Glucose Glucose and Oxygen 1. High blood glucose, can lead to Down-regulation of the glucose transporters 2. Low blood glucose, Diabetics can cause mental confusion, slurred speech, coma, and even death

What is meant by the receptive field of sensory neurons? Do more sensitive areas of the body have smaller or larger receptive fields? a. Lesser sensitive skin area-large receptive field b. More sensitive skin-smaller receptive field

A sensory neuron is activated by stimuli that fall within the neuron's receptive field Ex. two-point discrimination test a. Less sensitive skin area-many primary neurons converge on one secondary neuron (large receptive field) two pins 20mm apart are perceived as one pinprikc b. More sensitive skin areas are often have smaller receptive areas, one to one relation between primary and secondary neurons, two pins 2mm apart are perceived as separate.

Cells in the Nueural Layer 1. Photoreceptor cells 2. Bipolar cells 3. Ganglionic cells

A. *Photoreceptors* cells-first to receive incoming light rays 1. rods: cylinderical cells containing rhodopsin pigment that absorbs light, responsible for night vision in black & white 2. Cones-cone shaped cells, that include red, green, and blue photoreceptors and fucntion in bright lights and areresponsible for color vision 3. Rods and cones receive and transmit nerve impulses to B. *Bipolar cells*: neuron dendrites recieve nerve impulses from rods and cones, then transmit the impulses along axons to C. *Ganglion cells*: neuron dendrites receive nerve impulses from bipolar cells; axons converge to form the optic nerve that exits the back of the eye and carries impulses to the brain

- What are the three regions of the adrenal cortex, and what hormones does each region produce? Z. Glomerulua-Mineralcorticoids (Aldosterone) Z. Reticularis-Gonadocorticoids (Sex hormones) Z. fascisulata-Glucocorticoids (Cortisol)

A. Cortex's outer *Z. Glomerulosa* Mineralcorticoids (Aldosterone) affect mineral update-Sodium and potassium uptake in the kidney tubules B. Cortex's inner *Z. reticularis* Gonaldocorticoids (sex hormones)-Sexual development C. Mid cortex * Z. fascisulata* Glucocorticoids (Cortisol)-Increase blood sugar level by gluconeogenesis

2 types of PNS neuroglia A. Schwann cells: produce myeline sheath around PNS neuron axons 1. Neurilemma 2. Node of Ranvier B. satellite cells

A. Schwann cells (forms myelin) Flattened cells arranged in series around axons or dendrites; produce myeline sheet around PNS neuron axons 1. Neurilemma: outer nucleated cytoplasmic layer of SC. helps to regenerate damaged myelinated PNS neuron axons or dendrites 2. Nodes of ranvier: gaps/indentation in the sheath B. Satellite cells Support neurons in ganglia-bundles of neuron cell bodies in PNS

A. Electrical synapses B. chemical synapses-neurotransmitters Most common in NS

A. Those in which adjacent cells are joined by *gap junctions*-which allow ions to diffuse directly from cell to cell. 2. these synapses are found in glia, cardiac, and smooth cells B. which neurons communicate with effectors via neurontrasmitter. these synapses are most common in the nervous system

- Compare and contrast the ligands, effectors, and actions of the different adrenergic and cholinergic receptors. A. Cholinergic receptros 1. Nicotonic receptors-Sympathetic & CNS Ion-gated channel 2. Muscaronic receptors-Parasympathetic &CNS G-protein with 2nd messenger B. Adrenergic Receptors-Bind to NE

A. which Ach binds to have two types 1*Nicotonic receptors* a. Ach binds to and opens ion channels in the *postsympatic neuron*, allowing Na to enter and K to leave the neuron b. Na influx depolarize the neuron, causing a greater potential-if the depolarization is strong enough, an action potential is triggered in the postsynaptic cell c. Ligand-gated ion channels are _____-they open ion channels B. *Muscaronic receptors* found in the parasympathetic NS and CNS, Linked to G-protein with 2nd messengers 1. Ach binds to G-Protein-linked receptors, which activates G-protein intracellular, which activates 2nd messenger 2. Response Vary according to the receptor sub-type B. Adrenergic receptors alpha and beta, which are also G-protein-linked receptors and initiate 2nd messenger cascades (inside of the cell)

- How can one neurotransmitter exert different effects in different tissues?

Acethylcolamine (Acethyl coA+ Cholin): PNS Excitory in skeletal muscle/inhibitory in cardiac muscle Catecholamine: PNS, excitory in cardiac/ Inihibitory in smooth and gland

- What peripheral glands are stimulated to release their hormones via the trophic hormones from the anterior pituitary gland? Peripheral glands (5)

Adrenal glands, thyroid, gonads, and pancreas, parathyroids 1. Adrenal, gonad, thyroid functions are influenced by the hypothalamus and Ant. pituitary gland 2. Pancreas and Parathyroids are influenced by Humoral products (Glucose/ Calcium) CRH--> ACTH--->:adrenal cortex to secrete corticoid steroid GnRH->FSH &LH--> gonads to produce sex steroids TRH--->TSH--->Thyroid gland to release Thyroid hormone

- What regulates the amount of a particular hormone that is present in the bloodstream at a given time? *Control of hormone release*

All hormones are *reflex* of their reflex pathways A. all pathways involve 1. Stimulus 2. a sensor 3. Input signal 4. .Integration 5. Output signal 6. response

- What is the general method whereby hormones (and neurohormones) work? In what major ways do the mechanisms of amines, peptide and steroidal hormones differ? (e.g., extracellular signal transduction vs. intracellular protein synthesis)

Amine/Peptide(AA based) are water-soluble: extracellular signal transduction: 2nd messenger cAMP Steroid(steroid) are lipid soluble: intracellular protein synthesis-activates genes

- How do the anterior and posterior pituitary glands differ from each other?

Anterior (Adenohypophysis) 1. a true endocrine glands composed of epithelial tissues 2. secretes 6 hormones Posterior(neurohypophysis) 1. *extension of the hypothalamus*, composed of neural tissues 2. Stores/releases two peptide neuro-hormones produced by hypothalamus

- What is meant by astigmatism, glaucoma, emmetropia, presbyopia, myopia, and hyperopia? 1. Emmetropia 2. Presbyopia 3. Myopia 4. Hyperopia

Astigmatism: uneven surface on the lens/cornia, makes light to bend unevenly, causing blurry vision Glaucoma: elevated pressure within the eye-blockage in the canal of schlemm, aqueous humor builds up Emmetropia: relaxed state of Normal eye when it is focused on an object 20 ft or more away; incoming light rays are parallel and focused on the retina Presbyopia: Loss of lens accomodation due to a gradual lessening of lens elasticity as we age Myopia-can't see far: Nearsightedness, results from an eye that is too Long, distant object are focused in front of the retina's focal point *Concave lens* Hyperoipia-can't see near Farsightedness, from and eye that is too short, near objects are focused behind the retina's focal point *Convex lens*

- What does the blood-brain barrier consist of, and what is its purpose?

BBB consist of tightly joined brain capillary endothelial cells a. water, some electrolytes, glucose, and lipid soluble molecules (O2, CO2, Alcohol, caffeinine, nicotine, and anesthetics) b. Larger material (Protein), toxins (bacteria) and most drugs can't cross the BBB Protects from harmful substances, also interferes with therapatic drugs administered to the brain

- How do neurotoxins (especially those mentioned in class) affect nerve transmission?

By binding to Na, K, or Ca channels in the neuron membrane a. neurotoxins/local anesthetic=bind to and block Na channel b. blocked na channel-Na cant enter the axon(No depolarization)-no longer message send to the brain

- What are the main structural components of the central and peripheral nervous systems?

CNS: Brain and Spinal cord Most impulses that stimulate muscle to contract, and glands to secrete originate in the CNS PNS: outside the CNS; Consists primarily of cranial nerves and spinal nerves 1. Cranial nerves: carry signals to and from the brain 2. Spinal nerves: carry signals to from and the spinal cord 3. Both nerves are composed of sensory and motor neurosn Sensory( Afferent neurons) : cell bodies end near the CNS, conduct nerve impulses from the PNS to CNS Motor (Efferent neurons): cell bodies originate in CNS, conduct impusles from the CNS to muscle/gland

- What is cerebrospinal fluid composed of, what glial cells make it, from what is it made, and what is its purpose? Why would a spinal tap be performed?

CSF composition is similar to Blood plasma, more Na, H, Cl, Less K, Ca HCO3, Glucose, and protein Made by Choroid plexus (capillaries and ependynmal cells) in the brain ventricles 3 purposes of CSF 1. Buoyancy: CSF has similar density to the brain, allowing the brain to weight much less as it floats inside the cranium 2. Protection: provides a fluid cushion for the brain if the head is jolted 3. Chemical stability: means of rinsing metabolic wastes from the CNS and maintenance of homeostasis in the chemical environment Spinal tap withdraws a small sample of CSF from the subarachoid space for analysis for bacteria, viruses, etc

- What is the overall function of gray matter in the spinal cord? What functional types of neurons are found in the dorsal, lateral, and ventral horns? Gray matter (Spinal cord) forms 1. Dorsal horns 2. lateral horns 3. Ventral horns

Central H shaped core of SC, neurons involved in the spinal reflexes 1. incoming sensory axons; the dorsal root extends outward to the dorsal root ganglia (contains sensory neuron cell bodies) 2. cell bodies of autonomic motor neurons 3. somatic motor neuron cell bodies; the ventral root, with motor, neuron axons extend outward

- What structure allows the two cerebral hemispheres to communicate with each other?

Corpuss collasum

Where is cortisol produced? What are its actions? With what other hormones does cortisol have permissive effects?

Cortisol is produced from adrenal cortex-Increases blood glucose level, and feeds back to inhibit ACTH and CRH release CRH(Hypothalamus)->ACTH(Ant. Pituitary gland)-> Cortisol (Adrenal gland) Cortisol has a permissive effect-Required for *Glucagon* and catecholamine(Neurotransmitters)* to have its full effect

which hormones are primarily catabolic? *Cortisol*

Cortisol: increases blood glucose level; inhibits ACTH, CRH release 1. promotes gluconeogenesis in the liver 2. causes the breakdown of skeletal muscle protein 3. enhances lipolysis 4. Supresses the immune system 5. Causes Negative calcium balance-> decrease blood Ca level by decreasing Ca absorption and increasing excretion 6. Brain function-excess or difficiency can cause mood swing, alteration in memory and learning

Protein/Peptide

DNA, RNA, the RER, and Golgi apparatus 1. inactive prepro-hormones (In ER) ex. Pre-proinsulin 2. cleaved into Pro-hormones (in ER/Golgi ex. Pro-insulin 3. Pro hormones are packaged into secretory vesicles with proteolytic enzymes-cleaves into *active enzyme* in Golgi. ex. insulin -Dissolve in blood plasma and have short half-life *Cellular mechanism* 1. Peptide hormones bind to surface receptors and cause rapid cellular responses via signal transduction- cAMP 2nd messenger system 2. A few peptides also initiate synthesis of new protein

Hyposecretion

Diminishes or eliminates a hormone's effect 1. Insufficient lack of hormones production is caused by the Atrophy(Shrinkage) of gland due to disease Ex. Insufficient GH production in children leads to Dwarfism

- What causes electrical signals in neurons? What causes depolarization? Repolarization? Hyperpolarization? What ions and ion channels are involved in each? Ion movement across cell membrane creates electrical signal Flow of ions (Na and K) through opening inn the plasma membrane -Na infux causes depolarization -K moves out of the cell-> repolarization -Hyperpolarized: more negative than resting membrane potential (K gate closes more slowly)

Electrical currents in the body are created by the flow of ions (Na and K) through opening (ion channels) in the plasma membrane Depolarization: membrane becomes more positive AP is generated->more voltage gated Na channels are oepn-> depolarization rises upto 30mV Repolarization: Voltage moves back to resting potential Voltage gated Na will close, Voltage gated K will open, causing K to move out of neuron Hyperpolarization: potential becomes more negative a decrease in membrane voltage under resting potential (-90mv) because voltage-gated K channels are slow to close

- List the 5 paired lobes of the cerebrum and the main functions of each lobe 1. Frontal lobes a. Pre-frontal cortex b. precentral gyrus c. broco's area 2. Parietal lobes a. Post central gyrus (sensory areas) b. Wernick's area (sounding out unfamiliar words) c. primary gustatory cortex (Taste) d. aphasia (damage in wernick's area & Brocas) 3. Temporal lobes a. auditory areas (primary auditory cortex & auditory associaiton area) b. olfactory cortex c. memory 4. Occipital lobes-posterior cerebrum a. superior to the ____ b. Visual areas (primary visual cortex and visual association area) 5. The insula

Form the anterior portion of each cerebral hemisphere a. intellect, complex reasoning, personality, and memories of plans and social roles b. motor areas (primary motor cortex & motor association areas) involved in the control of voluntary muscle c. motor speech area at the base of the precentral gyrus in the left hemisphere Posterior to the frontal lobes a. contains sensory areas (primary somatosensory & somatosensory association areas) that responds to incoming stimulus from cutaneous and muscular receptors b. junction of parietal and temporal lobes in the left hemisphere, where unfamiliar words are sounds out c. receives taste impulses d. a langauge difficulty resulting from lesions(damage) in the wernick's and / or brocas areas Inferior to parietal lobes; contains the a. in the superior temporal gyrus; receives auditory fibers (CN VIII) from the ear cochlea for hearing) b. in the medial temporal lobes and infereior frontal lobes, receives and processes sensory info. from the olfactory tracts of CN 1. c. Memory of vocab, faces, and familiar objects is found in the superior temporal lobe a. cerebellum b. integrate eye movements and correlate visual images with other sensory stimuli medial structure deep within the lateral sulcus -integrate other cerebral activities and be invovled in language, taste, and the sense of balance -integrating sensory info. from visceral receptors

What is necessary for a graded potential to initiate an action potential? How do the actions inhibitory and excitatory post synaptic potentials (IPSPs & EPSPs) differ? 1. Inhibitory post synaptic potentials (IPSP) Hyperpolarization (More Negative) *Off Switch* 2. Excitory post synaptic potentials (EPSP) Depolarization (More positive) *On Switch*

Graded potential must Depolarizes the membrane to the *threshold voltage* -55mV-> AP will be generated 1. result from Hyperpolarization of the post synaptic neurons membrane; IPSP make the neuron less likey to fire an action potential (Off switch) 2. result from Depolarization of the post synaptic neuron's membrane-makes the neuron more likely to fire an action potential (on switch)

- Compare gray and white matter in the brain and spinal cord.

Gray matter: unmyelinated nerve cell bodies, dendrites, and axon terminals a. Nuclei: clusters of neuron cell bodies in the CNS b. Ganglia: a group of neuron cell bodies in PNS white matter: composed mostly of myelinated axons that form bundles called tracks (similar to nerves in the PNS) that interconnect regions of the CNS

- Which hormones are mainly anabolic in their actions, and which are primarily catabolic? *GH*

Growth hormone, . 1. GHRH & GHIH (Somatostatin): hypothalamus promotes/inhibits GH 2. GH from ant. Pituitary stimulates anabolic activity in endocrine and nonendocrine cells; Respond to GH: a. Liver secretes IGF's -act with GH to stimulate bone, cartilalge, and muscle growth b. IGF-direct energy and AA into protein synthesis c. Fat breakdown/Liver glucose output are increased

Peptide hormones

Hormones from Hypothalamus GHIH, GHRH, TRH, CRH, GnRH, PRH, PIH Hormones from Ant. Pituitary GH, TSH, ACTH, FSH/LH, PRL, MSH Calcitonin from C-cells of thyroid gland PTH from Parathyroid gland Insulin/Glycogen from pancreas Hormones from liver

What pathologies result from cortisol hypo- and hypersecretion? Hypercortisolim-Cushing's syndrome Hypocortisolism-Addison's disease

Hypercortisolim-Excess cortisol in the blood, causes *Cushing's syndrome* a. Hyperglycemia, muscle weakness, hypertension, moodiness, fatty deposits in the trunk and face b. causes are 1. adrenal tumor: secretes xs Cortisol 2. pituitary tumor: excess ACTH 3. Iatrogenic (physician induced)-due to cortisol medication Hypocortisolim-little cortisol in the blood, causes *addision's disesase a. hypoglycemia, hypotension, electrolyte imbalances, skin bronzing, dehydration, weight loss, and weakness

- What are the symptoms of hyper- and hypothyroidism, and what conditions result from each? How is each treated?

Hyperthyroidism-Grave's disease 1. warm, sweaty skin, heat intolerance 2. weight loss due to protein catabolism 3. Psychological disturbances 4. Rapid heart beat (Tachycardia) Hypothyrodism 1. cool skin, intolerance to cold 2. Myxedema-fluid under the skin, brittle nails, thinning hair 3. Fatigue=and slowed metabolism 4. slowed heart beat (Bradycardia) 5. Cretinism (mental retardation) in infants Primary Hypothyrodism-due to lack of iodine in the diet 1. Less TH is made-Negative feedback is removed 2. More TSH is secreted causing Thyroid hypertropy (bigger) 3. Treated with oral anti-thyroid medicine Hyperthyroidism-Graves disease 1. Thyroid enlargement/Goiter: antibodies combine with Thyroid TSH receptors and activate them 2. Exothalamus(bulging eyes) 3. treated by removal or destruction of all or part of thyroid gland, drugs that block conversion of T4 to T3.

- What conditions result from the hypo- and hypersecretion of GH?

Hypo- of GH: Dwarfism Hyper of GH: In children-Gigantism In adult-Acromegaly, jaw lengthening, coarse facial features, and growgth of hands and feets

What occurs in hypo- and hypercalcemia?

Hypocalcemia (TOO LITTLE calcium in the blood) Increase neural activity, causing sustained contraction (tetani) of respiratory muscles, resulting suffocation Hypercalcemia (TOO MUCH calcium in the blood) Decrease neuromuscular activity Hypercalcemia is usually a result of overactive parathyroid glands.

Which organs are partially endocrine?

Hypothalamus thymus pancreas ovaries testes kidney stomach liver small intestines skin heart placenta

- How does the hypothalamus control the secretions of both the anterior and posterior pituitary glands? List the neurohormones produced by the hypothalamus.

Hypothalamus controls the release of hormones of Anterior pituitay gland 1. GHIH (Inihibit relesae of GH) 2. GHRH (Release GH) 3. TRH (Release TSH) 4. CRH (Release ACTH) 5. GnRH (To release FSH/LH) 6. PRH(To release prolactin) 7. PIH (To inhibit prolactin) Posterior pituitary gland 1. Vasopressin-water balance 2. Oxytocin-uterine contraction during child birth/ milk ejection

- What general region of the ear (outer, inner, or middle) contains receptors for hearing & equilibrium?

Inner ears The cochlea: dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. The vestibular system: dedicated to balance

- Why does more eye strain occur when focusing on close objects than when looking at distant objects? Convergence of the eye-> Pupil constriction-> Lens accodation

Near response: require to focus the eye on objects closer than 20ft; a. Convergence of the eye-pupils begin to move medially b. Pupil constriction: to filter out peripheral light rays, minimize spherical aberrations from the lens c. Lens accomodation-change in the curvature of the lens via the 1. *cilliary muscle* around the lens contracts, narrowing its diameter 2. *Suspensory ligaments* that connect the ciliary muscle to the lens relax, allowing the stretched lens to become more convex 3. more convex lens refelcts light more and focuses light rays onto the retina

Permissive Hormones Thyroid hormones & Gonadotropic homones=reproductive system maturation Cortisol & Glycagon and catecholamine

Need to allow another hormones to exert its full effect Thyroid hormone is not present; *gonadotropic hormones* alone won't sufficient for reproductive system maturation.

- What happens if the spinal cord becomes damaged?

Paralysis, loss of ability to control muscles

- How does the transport of peptide hormones differ from that of steroidal hormones?

Peptide (water soluble) bind to the surface receptors and cause rapid cellular responses via signal transduction -Stimulate cAMP; 2nd messenger systems Steroid (Lipid soluble) they diffuse through CM, bind to the intra-cellular receptors, turn genes on or off, affecting protein synthesis (takes time) -Slower than peptide hormones -also can bind to membrane receptors, initiate rapid response

- Which glands are completely endocrine glands?

Pituitary gland Thyroid gland Parathyroid gland Adrenal gland Pineal gland

Nervous system stimulation-influences the posterior pituitary and adrenal medulla

Posterior pituitary a. Neurons in the hypothalamus produce neurohormones that are stored in the Post. pituitry until needed Adrenal medulla b. Nerve impulses during *Fight or Flight*-stimulates adrenal medulla to release Epinephrine and Norepineprhine c. Catecholamine

- What are the three basic chemical classes of hormones? From what organic molecules are the three classes derived? Which hormones are included in each class?

Protein/Peptide: DNA->RNA->PROTEIN-> ER Amine: 2 AA, Tryptophan and tyrosine Steroid: Cholesterol

- How do sensory (afferent) and motor (efferent) neurons differ functionally?

Sensory Neurons 1. cell bodies end near the NS, conduct nerve impulses from the PNS --->CNS Motor neurons 2. Cell bodies originate in the CNS-conduct impulses from the CNS ---> muscles and glands

How is thyroid hormone synthesized? *Iodine and AA thyrosin* What element is needed to synthesize thyroid hormone? *Iodine* In what functional way does the amine thyroid hormone differ from other amine and peptide hormones? *Lipid soluble*

TH is made from amino acid thyrosin and Iodine 1. Thyroid follicles are filled with colloid containing a protein precursor to TH called Thyroglobulin and enzymes. 2. TH is made from amino acid thyrosin and Iodine a. Iodine from Food is actively transported into Follicular cells b. Enzymes attach I-to tyrosine on the thyroglobuline molecules in the colloid to make T3 and T4 c. Thyroglobulin is endocytosed into follicular cells, where enzymes free T3 and T4 from the protein T3 and T4 are *Lipid soluble*-can diffuse out of the cells into the plasma and bind to thyroid-binding proteins a. Bind to nuclear receptors-initiate protein synthesis b. T4 is converted by enzyme to T3, active hormone in target tissues

What two hormones do the two different cell types in the thyroid gland secrete? 1. Calcitonin 2. Thyroid hormones: T3/T4 What are the functions of the two hormones? What hormone is produced by the parathyroid glands? PTH

Thyroid Glands: 1. C-cells secrete *Calcitonin* Decrease Ca plasma level by stimulating osteoblast=take Ca from plasma and deposit it into the bone 2. Follicular cells secrete *Thyroid hormones* (TH) T3 and T4=Metabolism, growth and development of all body cells Parathyroid glands PTH-Increase Ca plasma level by Stimulating Osteoclast=secrete acid and enzymes to dissolve bone and increase Ca level

In addition to GH, what other things are needed for normal tissue growth to occur? What other hormones have permissive effects with GH?

Tissue growth requires *GH, TH, and Insulin* 1. GH, TH, and IGF's: protein synthesis and cell divison a. Hypertrophy=increase in cell size b. Hyperplasia=increase in cell number 2. Insulin=Supports tissue growth by stimulating protein synthesis and providing glucose for energy

What specific nerve carries sound and equilibrium impulses to the brain? What nerve carries the impulses for sight? What would be the consequences of damage to either of these nerves?

Vestibulococchlear nerve (CN8) *Optic nerves (CN 2)

- What does 20/20 vision mean?

Visual acuity is usually measured with a Snellen chart. Snellen charts display letters of progressively smaller size. "Normal" vision is 20/20. This means that the test subject sees the same line of letters at 20 feet that person with normal vision sees at 20 feet.

- What structures/pigments allow the conversion of light into sensory impulses in the eye? What vitamin is necessary for one of the visual pigments?

Visual pigments in the rods and cones: 1. *Rhodopsin* (visual purple) in the rods a. Opsin protein b. Retinal: a photo-absorbing molecules made from *vitamin A* 2. *Photopsin*: in cones a. Retinal: same as found in rhodopsin b. Opsin protein: with different AA sequences that allow for three types of cones that absorbe light of 3 different wavelenghths

How are pitch distinguished by the brain? *region of basilar membrane that is vibrated*

a. Collagen fibers span the length of basilar membrane, increasing in length from the base (oval window) to the apex b. audible sound waves with frequencies between 20,000-20Hz are detected at different areas along the basal membrane c. audible sound waves set up perilymph waves that travel through the scalar vestibuli, flexing the vestibular membrane, transfering waves to the cochlea, which flexes the basilar membrane d. high frequency waves stimulate fibers near the base of the basilar membrane, vibrating the membrane at the high frequency e. Lower frequency waves: stimulate fibers near the basilar membrane apex, vibrating the membrane at the low frequency f. the stimulation of specific hair cells along the basilar membrane length is interpreted in the brain as sound of a certain pitch

Humoral products: Glucose and Calcium can influence hormone release High Glucose-> Insulin-> Lower BG Low Glucose->Glycogen-> high BG High Calcium-> Calcitonin (Thyroid gland)-> Low Ca Low Ca. -> PTH-> High Ca.

a. Glucose plasma concentration affect *pancreas* 1. High glucose levels-> cause pancreas to release Insuline, which decrease glucose level 2. Low glucose level-> pancreas to release Glucagon, increases glucose level b. Calcium plasma concentration influences * thyroid* and *parathyroid hormones* 1. High calcium level: thyroid gland to secrete *Calcitonin* decrease Ca level 2. Low calcium level: parathyroid gland to secrete PTH, Increase calcium level

*Mechanoreceptors* a. touch receptors b. Pressure receptors c. Proprioceptors

a. Merkel cells & Meissneier's corpuscles b. panician and Ruffini corpuscles c. sense the position and movement movements of body parts; found in muscle, tendons, and joint capsules

Amine hormones

a. derived from two amino acids (Tryptophan or thyrosin) 1. tryptophan -> *melatonine* in the pineal gland 2. tyrosine-> thyroid hormones and catecolamines 3. Catecolamine-> Dopamine, Epinephrine, and norepinephrine (neurohormones) that bind to cell membrane receptors 4. thyroid hormones act more as steroids-> can bind to intracellular receptors to activate genes

- What happens in hyperkalemia and hypokalemia? Change in ECF Concentration of K, and Ca alter elecrical activity of the nervous sytem a. Hyperkalemia b. hypokalemia

a. high blood K, shifts the resting membrane potential toward threshold, causing neurons to fire action potentials in response to smaller graded potentials, which can cause heart failure b. low blood k, hyperpolarizes neurons, making them less likely to fire action potentials, muscle weakness

How are loud sounds and pitch distinguished by the brain? 1. Loud sounds cause the organ of Corti to vibrate more vigorously

a. more hair cells are excited over a larger area of basilar membrane b. More nerve impulses are sent to the cochlear nerve c. brain detects intense activity from a large region of organ of corti and interprets it as loud sound

- Compare and contrast temporal and spatial summation. Summation: adding up post synaptic potentials (EPSP and IPSP) and responding to their net effect A. Temporal summation Occurs in same place—but at slightly different times b. Spatial summation occur in different locations—but at about the same time

a. occurs when one presynaptic neuron generates EPSP so rapidly that each is generated before the other decays; which can add up to threshold and cause an action potential b. occurs when EPSP from EPSP presynpatic neurons add up to threshold at the axon hillock of one postsynaptic neurons

- How do diverging and converging neural circuits differ? Give an example of each. a.Diverging circuit (One nerve fibers->several post synaptic cells) (2 motor neuron controls many skeletal muscle cells) b. Converging circuit (Several neurons->one neuron) ( brain area for equilibirium)

a. one nerve fiber branches and synapses with several postsynaptic cells, one neuron control many other cell. ex. 2-motor neuron control many skeletal muscle cells b. several neurons synapse with one neuron or a neuronal pool; allows input from several body regions (eyes, inner ear) to another area (brain area for equilibirium)

- What are referred pain and phantom pain?

a. originates in one area, but is felt in another area and occurs because multiple primary sensory neurons converge onto a single ascending track b. ampute feels pain-in the amputated limb also occurs because nerve converges to spinal cord

*Neuroglial cells of the CNS (4)* A. Astrocytes-Form BBB B. Microglial cells-Phagocytic cell C. Ependymal cells-produce CSF D. Oligodendrocytes-Myeline sheath Auto-immune destruction of myelin sheath: Multiple scleroisis

a. star-shaped cells with many processes, most abundant glial cell in the CNS 1. Structural support bet. cappillaries and neurons of the CNS-Form blood-brain barrrier 2. take up & release Ion (k) to control the neuronal environment b. small, phagocytic cells that destroy pathogens in the CNS c. epithelial cells that line brain ventricles and the spinal cord central canal 1. produce and help circulate *cerebrospinal fluid* 2. source of neural stem cells to replace neurons D. shorter & fewer process than astrocytes 1. produce myelin sheath (lipid & protein) around CNS neuron axons, which insulates axons, increasing speed of nerve impulse conduction 2. involves autoimmune destruction of the myelin sheath

Antagonistic Glucagon& GH vs Insulin Glucagon-increase BG Insulin-decrease BG GH-decreases Insulin receptor

hormones have opposing effects 1. act through different pathways, *down-regulate* the number of other hormones receptors Ex. Glucagon and growth hormones are antagonistic to *Insulin* because they rise BG levels where insulin lowers BG dlevels. GH decreases insulin receptors

- What are the three major parts of the brain stem? What are the main functions of these parts? Why is it sometimes called the primitive brain? Primitive brain-involved in basic life functions: 12 cranial nerves originate from Brain stem

include mid brain, pons, and medulla oblongata 1. Mid brain A. cerebral peduncles composed of pairs of structures composed of ascending and descending nerve tracks that connect to the cerebrum to other part of the brain B. corpora quadrigemini 1. Superior: visual reflexes 2. Inferior: auditory reflexes 2. Pons - consists of white fiber tracks that connect with the thalamus, cerebellum and medulla oblongata -Nuclei of pons function with MO to regulate breathing 3. Medulla oblongata contains somatosensory and corticospinal tracks a. *corticospinal (pyramidal): descending nerve tracks (motor cortex) cross over(decussate) in the medulla oblongata; that carry motor impulses from the brain to the spinal cord; thus the right brain controls the left brain of the body and left brain controls the right side* b. somato-sensory: ascending nerve tracks pass through the medulla , pons, and midbrain to their way to the thalamus, then somatosensory cortex

Synergism Glucagon+Epinephrine+Cortisol=Max. BG level

the effect of interacting hormones is more than * addictive* Ex. Blood glucose levels are increased by *Glucagon, Epinephrine, and Cortisol* Glucagon: BG at 10mg/dl Epinephrine: BG at 5mg/dl Both Glucagon and epinephrine: BG to 22mg/dl

- What is the overall function of white matter in the spinal cord? What do the ascending and descending tracts of the spinal cord do? White matter 1. Ascending tracks (Sensory info) 2. Descending tracks (Motor info)

urrounds the central gray matter, consists of columns of myelinated ascending and descending nerve tracks 1. dorsal and lateral SC take sensory information to the brain 2. ventral and deep lateral SC, take motor info. from the brain to the cord