Physiology Exam I

Hyperpolarization ->action of rods-> alter synpatic activity with biopolar, amacrine, horizontal cell-> AP ganglion cells of optic N-> relay to thalamus nucleus LGN-> 1* visual cortex (occiptal lobe)

• hyperpolarization via closing Na channels
• rod leading -> bipolar cells, amacrine cell, horizontal cells AP in the ganglion cells

• depolarization of hairs cells
• spiral ganglion cells
• Cochlear branch of CN VIII (Vestibularchochlear N)
• Cochlear nuclei of medulla oblongota

• on of the main Association cortex
• the homeostatic and sensorimotor systems are integrated into
• conscious thoughts
• Tertiary Motor Cortex- strating pt for output from the brain
• site of Working Memory ( short-term memory)

• 1>2>3>3>2>1
• sensory cortex > PTO> Prefrontal Cortex< 2* motor<1*motor cortexs(cerebal cortex highest motor heiarchy)> alpha motor neuron> skeletal muscle

• posterior association cortex
• where parietal, temporal, occipital all abut each other
• association take the form of symbols & language
• "library"
• multimodal info process

gets input from thalamus 2* doesn't

• perceiving the external world & moving the body (skeletal muscles) through the external world
• input - perception
• output- moving skeletal muscle through

• perceiving the internal environment of the body & regulating the viscera via Endocrine & autonomic system
• input-perception of internal environment
• output- regulating via endocrine & autonomic

• cardiac muscles
• smooth muscles
• exocrine glands
• endocrine glands

• Astrocytes
• microglia
• Oligodendrocytes
• Schwann cells
• 10:1

• sustain neurons metabolically (nutrition) & trophically (growth)
• support them physically: structural function
• maintian extracellular fluid composition (uptake of K+)
• maintain blood-brain barrier

scavenger immune cells in CNS

myelination of CNS axon

myelination of PNS axons

tight junctions in capillaries prevent diffusion of substances from blood to brain extracellular space, except Water & Lipid soluble substances

• input end
• reception of information as Graded potential

metabolisms, gene expression, protien synthesis, graded conduction

site of generation of AP (action potential)

transmission of AP

• secretion of NT
• output end

• neurons
• cardiac muscle cell
• skeletal muscle cell
• smooth muscle cell

• = change in membrane potential =flow of ions across the neuron's membrane
• because of ion channels

• caused by ligand-gated channels (NT- ligand)
• take on any value
• come about b/c ligand gated ion channel stays open for a variable amout of time

• fixed changes
• caused by voltage gated ion channels
• stay open for a fixed amount of time, allowing only the same amount of ions to pass each time the voltage gated channel is open

fast Na+ channels go to an inactive state after they close

• high (-) V force keeps Na channel closed by 1st gate
• relatively (-) V force ( threshold) opens 1st gate Na+ enter
• high (+) V force close Na+ channel via 2nd gate Na channel is inactive
• relief of (-) V force open K gate hyperpolarization
• increase in (-) V force Na 2nd gate is replace by 1st gate
• High (-) V force membrane V keeps both Na & K closes

• to enhance the conduction of AP along the axon
• is an insulator
• depend on electric field and not on diffusion of ions
• fatty sheath
• nonmyelin is depend on distance of thershold to adjacent channels

• Na-K ATPase
• 3Na -out
• 2K -in
• requires ATP
• after 4 minute of brain deprived of blood flow Na and K are equilibrate
• ischemia --> why stroke cause death to neural tissue

• greater the influx of Ca2+
• more NT is released into synaptic cleft

• Presynaptic ending - recieves AP ->increase perm. to Ca2+ ->exocytosis of NT from presynaptic vesiscles
• into Synaptic cleft-> interaction with NT with Postsynaptic cell NT receptors ->AP

• T- addition/subtraction of two synaptic inputs over a short time interval (happening sequentially)
• S- addition/subtraction of two synapt inputs occurring simultaneously but different location

• E- depolarization Na or Ca of postsynaptic cell
• I- hyperpolarization Cl influx or K efflux

• elicit EPSP or IPSP in postsyn. element via ligand gated ion channel
• Ach
• Glut- EPSP
• Asp-EPSP
• GABA -IPSP
• Gly

• post synaptic element forms a specialized extrusion
• cortical & hippocampal pyramidal neurons

• presyn element dose not terminate but exist along the course of the axon
• cerebellar granule cell axons

• amplify or dampen the effectiveness of NT in either pre- or postsyn using 2nd messenger system
• NO
• biogenic amines - NEPI, DO, EPI, histamine,

• Ultimately the body can use the same NT for different effects depending on where it binds in the NS or periphery
• Ex. EPI alpha1, alpha2, beta1, beta2

• both receptors Ach bind
• M-Gprotein receptor->everywhere else
• N- ion channel ->skeletal muscle

• G-structures made of cell bodies & dendrites
• clusters or sheets of neurons
• W-structures made of axons, fibrous texture,
• columns, nerves, commissures , fasciculus, lemniscus, peduncle

• loose grouping of nuclei in brainstem involved in controlling levels of awareness and alertness of the brain
• make neuromodulators

• involved w/ UNconscious reflexes of both a motor & homeostatic nature
• Pon
• Medulla
• Midbrain
• all 3 involved in motor coordination & organization of skeletal mus. movement

• exist @ level of brainstem
• involed in motor coordination & organization of skeletal mus. movement

• Diencephalon
• relay station for conscious sensory input, regulation of states of arousal

• Diencephalon
• regulation of endocrine system, autonomic system, & emotional rxns

• Basal ganglia- motor planning & conscious awareness
• Limibic system (Hippocampus & Amygdala) - memory
• emotions, drives (sex, hunger)

• GI tract: Mechanoreceptors, gustatory sensation, chemoreceptors, nociceptors
• Cardio: bareoreceptors, stretch receptors, nociceptors, chemoreceptors
• Pulmonary system, Urogential system: stretch receptors

• Reflex loop: mediate by spinal interneurons, relay to NTS, ->synapse w/ spinal cord, pontine, medulla-> efferents->ANS preganglia
• Central integration w/ senosrimotor system: relay to NTS->hypothalamus or limbic (amygdala) -> hormonal output

• endocrine system via Hypothalamus
• ANS via NTS, hypothalamus, amygdala, & brainstem

• Sympathetic NS
• preganglionic neurons at T & L level of spinal cord
• postganglionic neurons are in sympathetic trunck
• unified response

• Parasympathetic NS
• preganglionic neurons is in Brainstem or Sacral spinal cord
• postganglionic neurons is close to effector organ
• localized/ discrete reponse

cells which transduce environmental energy into changes in membrane potential

the energy form that activates the sensory receptor

the type of energy to which a receptor best responds

activation of a specific type of receptor gives rise only to a single type of sensation

sensory modalities are kept separate from one another in their assent to the brain

• chemical -chemoreceptors
• light- photoreceptors
• thermal-thermoreceptors
• pressure, vibration, stretch, touch - mechanorecptors Ex. Somatosensation, auditory, vestibular
• pain- nociceptors

• 1) Stimulus Type
• 2) Stimulus Location
• 3) Stimulus Duration
• 4) Stimulus Instensity

• C- many receptor axons synapse to a post-syn cell
• increase signal over a nosiy background
• D-single receptor axon synapses w/ many postsynaptic cells
• amplify the effect of the single receptor

most active cells inhibit their neighbors, increases sensation contrast

• Stretch
• Pain
• Temp
• Pressure
• Vibration
• Touch

• Both Ascending somatosensory tracts- sensations from R side body are processed in L side of Forebrain & vice versa
• D- cross-over in medulla
• touch, pressure, & vibration
• A-pain & temp cross-over in spinal cord

from arm, shoulders, neck

legs & trunk

• Vis- Lateral geniculate nucleus
• Aud- Medial geniculate nucleus

• Semicircular Canals- detects Angular acceleration of head
• Utricle & Saccule - detect Linear acceleration of head