Physiology EXAM 1

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know the composition and characteristics of ECF and ICF

- what ions they contain - how changes in these ions or in charge will affect the polarization state of the cell ECF: ✰ Na+: high ✰ K+: low ✰ Cl-: high ✰ anionic proteins & phosphates: low ✰ Ca++: high ICF: ✰ Na+: low ✰ K+: high ✰ Cl-: low ✰ anionic proteins & phosphates: high ✰ Ca++ low

pain sensations

-nociceptors detect pain - free nerve endings, all tissues except brain and spinal cord - mechanical, thermal, or polymodal responsive - pain pathways: 1) spinal reflex pathway 2) ascending pathway to the brain (diverging circuit example) - referred pain

cell that synapses with sensory neurons

-non-neural receptors -most special senses receptors are cells that release neurotransmitter onto sensory neurons, initiating an action potential ex: hair cell

afferent sensory systems

-sensory pathways detect -neural pathways conduct to CNS

sensory receptor cells

-some regenerate: olfaction (note these are PNS neurons); taste -both regenerate from dedicated basal cells -others do NOT (in humans): photoreceptors, hair cells

threshold for odor detection

-very low: only a few molecules need present to be perceived as an odor -define adaptation: as decreasing sensitivity; olfactory receptors adapt quickly

define unit of Hertz (Hz)

1 cycle per second

2 somatic sensory pathways

1) crossover in spinal cord (synapse in dorsal horn): coarse touch, temperature, nociception (*some nociception are reflexes that do not involve brain) 2) ascend to medulla and cross over: fine touch, proprioception, vibration sensory pathways synapse in thalamus, sensations are perceived in the primary somatic sensory cortex

"natural" suppression mechanisms

1) mechanical somatic sensation and the gate theory of pain 2) endogenous analgesia systems: specific areas of the brain can release endogenous opioids (neuropeptides) with morphine-like action to block neurotransmitter release and promote inhibitory postsynaptic potentials

path of light through the retina

1. Ganglion cell layer -axons of optic nerve -ganglion cell 2. Bipolar cell layer 3. Photoreceptor cell layer -cone -rod

7 classes of neurotransmitters

1. acetylcholine 2. amino acids (glutamate, glycine) 3. amines (dopamine, serotonin, epinephrine) 4. purines (ATP) 5. gases (NO) 6. lipid derived (endocannabinoids) 7. neuropeptides

explain how the Na+/K+ ATPase along with the Na and K leak channels generate a negative resting potential

1. sodium ions bind high affinity sites 2. ATP hydrolysis: attachment of phosphate group changes protein conformation, release Na+ 3. conformation changes increases affinity of potassium sites: K+ binds and P released 4. return to original shape, K+ released because we have a lot of K+ leak channels, we are always losing positive charge and thus have slightly negative charge on the inside

describe 4 major events of sensation

1. stimulation of sensory receptor 2. transduction of the stimulus 3. generation of action potentials 4. integration of sensory input in the CNS

gustatory receptor cell

NOT neurons - modified epithelial cells that synapse with first-order taste neurons of the gustatory pathway

define homeostasis

"standing still" maintaining relatively stable state of conditions in the body

electrical synapse

- gap junctions: tunnels called connexons - bidirectional or one-way flow - speed and synchronization effect

define stimulus adaptation

- slow adapting receptor: TONIC - fast adapting receptor: PHASIC

tectorial membrane

a gelatinous membrane projecting over and in contact with the hair cells of the organ of Corti in the cochlear duct

Eustachian tube

a narrow tube between the middle ear and the throat that serves to equalize pressure on both sides of the eardrum

amacrine cell

a neuron in the retina that interconnects adjacent ganglion cells and the inner processes of the bipolar cells

ganglion cell

a neuron located in the retina that receives visual information from bipolar cells; its axons give rise to the optic nerve

oligodendrocyte

a type of glial cell that forms myelin in the central nervous system

neuronal regeneration

ability of cells to replicate or repair, typically in PNS -PNS regeneration: steps in process, positive roles of macrophages and Schwann cells -CNS failed regeneration: scar formation, negative environment, debris and glial cell proliferation

define sound waves

areas of compression or rarefraction (high or low pressure) of molecules vibrating

middle ear

auditory ossicles, malleus, incus, stapes, Eustachian tube (connects to pharynx, throat) ✦ air-filled; auditory ossicles transmit and amplify sound vibrations from the eardrum to the inner ear at the oval window

define central nervous system (CNS)

brain and spinal cord

dendrites

branchlike parts of a neuron that are specialized to receive information

define AFFERENT division

brings information from the body (peripheral organs) TO the central nervous system ✷ somatic senses: tactile, thermal, pain, proprioceptive ✷ special senses: smell, taste, vision, hearing, equilibrium

sensory receptors

can be neurons of a non-neural cell: know the identity for each special sense

are body fluids insulators or conductors?

conductors

papillae

elevations on the tongue where taste buds are found, provide a rough texture to the upper surface of the tongue

photoreceptor

light

what are the CNS glia cell types?

oligodendrocyte, microglial cell, astrocyte, ependymal cell

olfactory (I) nerves

on each side of nose, bundles of axons of olfactory receptor cells form the right and left olfactory (I) nerves

voltage gated channels

open and close in response to changes in membrane potential

mechanically gated channels

open and close in response to physical deformation of receptors ➣ particular pressures applied

taste pore

opening in the taste bud

microglial cell

phagocytic glial cell that removes waste products from the central nervous system

synapse anatomy

presynaptic cell, postsynaptic cell, synaptic cleft, axodendritic, axosomatic, axoaxonic

basal cells of olfactory system

stem cells that continually undergo cell division to produce new olfactory receptor cells, which live for only about two months before being replaced

basal cell of gustatory system

stem cells that produce supporting cells, which then develop into gustatory receptor cells

define receptive field

stimulated physical area, specific group of chemicals, or particular set of sound frequencies that causes a response in that neuron

taste transduction of salty and sour

stimuli (salty, Na+ or sour, H+) enter receptor cell via ion channels ➝ depolarizing receptor potential ➝ voltage-gated Ca++ channels open ➝ synaptic vesicle release ➝ neurotransmitters to first-order taste neuron

what dictates function and behaviors of cells?

structure and composition (features) - size, shape, organelles, gene expression

Schwann cell

supporting cells of the peripheral nervous system responsible for the formation of myelin

supporting cell of gustatory system

surround about 50 gustatory receptor cells in each taste bud

synaptic end bulb

swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse

what are the somatic senses?

tactile, thermal, pain and proprioceptive sensations *proprioceptive: knowledge about where your body's position is without other senses

taste transduction of sweet, bitter, umami

tastant binds gustatory receptor ➝ activates G protein ➝ 2nd messenger depolarizes cell ➝ Ca++ influx to ICF from a) ECF and b) ER (endoplasmic reticulum) ➝ intracellular Ca++ causes synaptic vesicle release ➝ neurotransmitters bind first-order taste neuron

vestibular apparatus

the receptive organs of the inner ear that contribute to balance and perception of head movement (equilibrium) -fluid-filled and houses receptor organs for equilibrium -non-neural receptors detect changes in body position and speed because forces of gravity and acceleration act on the stereocilia -otolith organs (utricle and saccule) and semicircular ducts and crista

what can pass freely through blood-brain barrier?

water, lipid soluble materials lipid soluble: oxygen, carbon dioxide, caffeine, nicotine, steroid hormones, alcohol, barbiturates, some antihistamines

define resting membrane potential

when a cell is at rest (unstimulated), the voltage that exists across the plasma membrane is the resting membrane potential

epithelial tissue

★ cover external and internal surfaces ★ apical and basolateral sides with discrete functions ★ functions: barrier, absorption, secretion

production and properties of CSF: "sinks"

- arachnoid villi: cobweb fingers that project from the subarachnoid space into venous sinuses - venous sinuses connect with venous return of blood to the heart

production and properties of CSF: sources of "faucets"

- define choroid plexus (in 3rd and 4th ventricle): network of capillaries in ventricle wall surrounded by ependymal cells - CSF made via transepithelial transport: the movement of solutes across epithelial cells - ependymal cells secrete Na+, creates osmotic gradient that draws water into the space - CSF contains no cells, little proteins, lots of ions - ependymal cells are multiciliated: have dozens of cilia - CSF is circulated by the ependymal cells that all line the CNS cavities, through the action of their beating cilia

spinal cord organization

- extend from base of brain stem to base of spine - regions along trunk attach to PNS spinal nerves: cervical, thoracic, lumbar, sacral, coccygeal - forked structure of spinal nerves ➣ they are mixed nerves: sensory AND motor ➣ dorsal (back) carries sensory (afferent) info to CNS ➣ ventral (belly side) carries motor (efferent) info to muscles & glands

thermal sensations

- free nerve endings - TRP (transient receptor potential) channel proteins, heat or cold responsive, chemical responsiveness

tactile sensations

- free nerve endings and encapsulated (corpuscles) and sensory functions - example of Pacinian corpuscle: stimulus transduction

what does the CSF provide?

- mechanical protection: CNS is buoyant, floats in CSF; this provides padding, protection from bruising, also reduces weight and pressures on brain (blood pressure, local pressure on neurons, nerves) - chemical protection: environment for chemical signaling - nutrient delivery, waste exchange: CSF is dynamic: made constantly and flushed out to the circulatory and/or lymph systems

brain

- simple multicellular organisms have nerve nets; increasingly complex brains cluster neurons - evolution of clusters led to forebrain, which in humans dominates the brain; brain is precious and must be sheltered/protected

spinal cord information processing

- spinal cord is highly organized ➣ compartments contain ascending or descending tracts (axons!) ➣ ascending tracts carry sensory info to the brain, descending carry commands to motor neurons - cross section: see compartments as gray matter butterfly shape surrounded by white matter - simple or complex routes ➣ sensory neuron ➝ spinal cord ➝ motor neuron (reflex arc) ➣ sensory neuron ➝ spinal cord (and may cross over) ➝ ascend to brain ➝ descend from brain ➝ motor neuron

protection of the brain

- strategy of many layers with different physical and chemical properties - skin (epidermis, dermis) - cranium - meninges (aka membranes) ➣ dura mater: dense connective tissue ➣ arachnoid mater: loose connective tissue ▶ subarachnoid space ▶ cobweb-like spaces hold the cerebrospinal fluid (CSF) ▶ brain also contains caverns that contain CSF: lateral ventricles (left, right), third ventricle, fourth ventricle (which is continuous with the central canal of the spinal cord) ➣ pia mater: thin membrane directly adherent to brain, spinal cord - neurons of brain ➣ blood-brain barrier (BBB) ➣ glia

chemical synapse

- uses neurotransmitters - know the 7 types of neurotransmitters ⇨ 6 are small molecules: acetylcholine, amino acids, amines, purines, gases, lipids ⇨ 1 is larger, the neuropeptides ⇨ CNS uses many neurotransmitters ⇨ PNS: mainly acetylcholine, norepinephrine, epinephrine

spinal cord protection

- vertebrae - 3 meninges with CSF: dura mater, arachnoid matter, subarachnoid space with CSF, pia mater, and note central canal is a cavity at the very center with CSF, CSF drains to lymphatic along the spine

outer hair cells

-are electromotile: change shape (shorten, elongate) in response to sound -stereocilia project into (endo)lymph and push against tectorial membrane, act as a cochlear amplifier that allows hearing of quiet sounds

smell: olfactory system

-gross anatomical terms: nose, nasal cavity, olfactory epithelium, cranial nerve, olfactory bulb, olfactory tract

mechanical somatic sensation and gate theory of pain

-touch, pressure, or vibration can suppress pain sensations, a concept known as gate control theory of pain -within spinal cord are interneurons that normally inhibit second-order neurons of ascending pain pathways- an action that prevents transmission of pain signals to the brain example: if you bump your foot, your impulse is to rub it; mechanical stimulus in local area provides relief because you stimulate mechanoreceptors and neural circuits are connected; pressure leads to divergence and inhibits nociceptor pathway

inner hair cells

-undergo mechanoelectrical transduction -stereocilia project into (endo)lymph, which is rich in K+ -tip link proteins open mechanically-gated cation channels ➔ K+ from (endo)lymph enters ➔ depolarizing receptor potential ➔ opens voltage-gated Ca++ channels ➔ Ca++ entry causes synaptic vesicle release of neurotransmitters to first-order neuron -tip link proteins can also close mechanically-gated cation channels ➔ K+ not able to enter cell ➔ hyperpolarizing receptor potential

methods for removal of neurotransmitters

1. diffuse out of synaptic cleft 2. enzymatic degradation 3. cell uptake- return to axon terminals for reuse or transported into glial cells

neuron function relies on 4 types of integral membrane proteins, which are membrane channels

1. leak 2. ligand gated 3. mechanically gated 4. voltage gated *know under what conditions are they open or closed

pathway that the cerebrospinal fluid follows beginning from a site of production and ending with a site of reabsorption

SECRETION: choroid plexus in 3rd and 4th ventricles ➞ ependymal cells transport Na+ into space, and water follows (osmotic gradient) ➞ cilia on ependymal cells drives CSF circulation around the brain, spinal cord REABSORPTION: drainage occurs 1) in the brain at arachnoid villi, which project into the venous blood circulation and 2) also via arachnoid villi associated with the spinal cord, but those connect to lymphatics

what are the PNS glia cell types?

Schwann

oval window

a small, membrane-covered opening between the middle ear and inner ear into which the footplate of the stapes fits

astrocyte

a star-shaped glial cell with numerous processes (extensions) that run in all directions -most numerous -maintain BBB -maintain chemical environment

cochlea

a winding, cone-shaped tube forming a portion of the inner ear and containing the organ of Corti

process of synaptic signaling

action potential ➝ depolarization opens Ca++ voltage-gated channels ➝ Ca++ triggers vesicle/membrane fusion ➝ neurotransmitter release

special senses

afferent division of sensory input for the nervous system

define intensity

amplitude

define action potential

arise at a trigger zone, typically axonal hillock ✺ ultimately propagate along the axon; regenerated away from axon ✺ when Na+ flows in, local current flow triggers voltage-gated Na+ channels in adjacent membrane to open ✺ involve voltage-gated channels - voltage-gated channels: Na+ and K+ - location, amplitude, all-or-nothing, distance traveled - know sequence of ion flow, ion permeability, and cycle of each gate opening/closure - define the refractory period (incapable of responding) ➣ absolute: Na+ open and then close ➣ relative: Na+ are resting; stronger stimulus than normal needed to trigger action potential because not all the gates are reset and K+ gates are open (losing + charge) - propagation: regenerative nature - conduction: continuous, saltatory - stimuli can be subthreshold, threshold, suprathreshold - effect of chemical factors on electrical activity: K+, Na+, Ca++ - clinical application: how conduction is altered in demyelinating diseases

define taste aversion

avoidance of foods that upset the digestive system -because of taste projections to the hypothalamus and limbic system, there is a strong link between taste and pleasant or unpleasant emotions; sweet foods evoke reactions of pleasure, while bitter ones cause expressions of disgust

olfactory tract

axons of mitral cells form the olfactory tract; some of the axons project to the olfactory cortex in temporal lobe where conscious awareness of smell occurs

visual pathway to the brain

axons of retinal ganglion cells from the optic (III) nerves ➔ meet at optic chiasm ➔ crossover of axons ➔ visual information from the right visual field goes to left side of brain AND visual information from left visual field all goes to the right side of the brain ➔ optic tract ➔ thalamus ➔ connects to the primary visual cortex of the occipital lobe

law of mass balance

balance of input and metabolic production with output via excretion or metabolic removal

mechanoreceptor

bend, stretch, pressure

diencephalon

between brain - thalamus, pineal gland, hypothalamus, pituitary gland

lipid component of cell membrane

bilayer = fluid mosaic model: sea of lipids with protein rafts (75% phospholipids, 20% glycolipid, 5% cholesterol- percentage impacts water permeability)

endogenous analgesia systems

can suppress pain: triggered by extreme stress/trauma -people experiencing severe damage but not feeling any pain

define neuronal plasticity

capacity of the nervous system to modify itself, functionally and structurally, in response to experience and injury example: networks change; connections change by sprouting new dendrites or altering synaptic contacts example: changes at the cellular level (e.g. macromolecules, like protein expression)

ligand gated channels

channel that opens when a neurotransmitter attaches ➣ particular molecule must be there as a key

leak channels

channels that are always open and allow ions to move along their gradient ➣ random, leak across just based on opening and closing; molecules move with respect to electrochemical gradients

chemoreceptor

chemicals in air (sense of smell), fluid

odorants

chemicals that bind to and stimulate the receptors in the olfactory cilia

limbic system

cingulate gyrus, hippocampus, amygdala; the emotional brain

auditory pathway

cochlear branch of vestibulocochlear nerve ➔ brainstem ➔ thalamus ➔ primary auditory cortex -information from each cochlea goes to the left and right auditory cortex (information sharing!)

capillary in BBB

composed of epithelial cells with many tight junctions TIGHT JUNCTION: interlocking protein complexes; seals adjacent cells to solute flow

define perception

conscious awareness and interpretation due to involvement of the cerebral cortex *sensory info that does not go to the cerebral cortex is unconsciously processed: e.g. sensing of blood pressure sent to the cardiovascular center of medulla

define sensation

conscious or subconscious awareness of changes in the external or internal environment ex: touch, heat

pigmented layer

consists of epithelial cells that contain melanin

blue cone

contain blue-sensitive pigment -absorbs light at wavelength of 420 nm

green cone

contain green-sensitive pigment -absorbs light at wavelength of 530 nm

red cone

contain red-sensitive pigment -absorbs light at wavelength of 560 nm

pericytes in BBB

contractile cells that wrap capillaries to promote and maintain tight junctions with their secretions

define feedback system

controlled variable ➞ monitored by receptors ➞ control center ➞ effectors ➞ response

what allows the 2 hemispheres of the brain to communicate?

corpus callosum; band of white matter that connects the hemispheres (axons)

crista in semicircular ducts

cupula, hair cell, stereocilia, tip link proteins, mechanically gated K+ channels, (endo)lymph

define and identify the following cell type, their characteristics, and their functions: NEURON AND ITS PARTS

dendrites, soma, axon, node of Ranvier, axon hillock, trigger zone, axon terminal, synaptic end bulb, axonal transport, white matter, gray matter

otolith organs (utricle, saccule)

detect linear acceleration, deceleration; vertical acceleration, deceleration, head tilt transduction: tip link proteins on stereocilia will open and close mechanically gated ion channels as movement occurs

outer ear

ear (pinna), auditory canal, eardrum (tympanic membrane) ✦ collects sound waves and; tympanic membrane (eardrum) vibrates and transmits vibrations to middle

tympanic membrane

eardrum; thin, semitransparent structure between the external auditory canal and middle ear; when sound waves strike it, it vibrates and then transmits vibrations to middle ear

stimulus modality

encoded by sensory receptor and neural pathway = "labeled lines" ❊ thalamus = relay station example: taste is perceived when a stimulus activates a gustatory receptor and its path to the gustatory cortex in the insula region of the brain example: smell is perceived when a stimulus activates an olfactory cortex in the temporal lobe of the brain

define lateral inhibition

enhances contrast and makes a stimulus easier to perceive

midbrain

eye movement

define cerebral lateralization, give examples

functional areas in the cerebral hemispheres that are NOT symmetrical concentrated on LEFT: ✪ language, verbal, mathematic skills; "analysis" ✪ examples: reasoning, numerical/scientific skills, spoken & written language, use and understanding sign language concentrated on RIGHT: ✪ spatial skills, "creative" ✪ examples: music and artistic awareness, space and pattern perception, recognizing faces, patterns, emotional content of language, odor discrimination

neural circuits

functional group of neurons that process information - characteristics can include: divergence, convergence, reverberate, parallel - neuron modulation: excitatory, inhibitory - summation of postsynaptic potentials: spatial, temporal - clinical application: neural circuits blocked using drugs that modulate voltage-gated channels, ex. novocaine and lidocaine

ependymal cell

glial cell that lines membranes within the brain and spinal cord and helps form cerebrospinal fluid

what can pass with regulated passage through blood-brain barrier?

glucose and other water-soluble substances example: glucose transporter proteins in the membrane quickly move glucose to the brain; brain needs a lionshare of glucose in our bodies for its anaerobic metabolism

regions of gray and white matter

gray matter: cortex, basal ganglia, limbic system white matter: corpus callosum

visual sensory system

gross anatomical terms: retina, optic (III) nerve, optic chiasm, optic tract

taste: gustatory system

gross anatomical terms: tongue, papillae, taste bud

insula

gustatory cortex

gustatory pathway to the brain

gustatory receptor cell ➝ first-order taste neurons ➝ axon in one of three cranial nerves, facial (VII), glossopharyngeal (IX), or vagus (X) ➝ go to gustatory nucleus in medulla ➝ project to 3 places: thalamus, limbic system, or hypothalamus from thalamus ➝ gustatory cortex: where we get our conscious awareness and discrimination of taste activating different combinations of gustatory receptor cells is thought to code for unique tastes in our brain

complex sensory neuron

have nerve endings enclosed in connective tissues capsules ex: Pacinian corpuscle that senses touch

basal ganglia

help control movement and muscle tone

stimulus location

how sensitive various areas of the body are; how innervated, how big the receptor fields are, if there is any overlap ❊ 2 point discrimination ❊ acuity: sharpness of perception example: back has big receptor fields that do not overlap; body does not know the exact place; lack acuity with big sensory receptors example: hand has very small sensory fields, lots of overlap, body can discriminate and tell where stimulus is example: auditory uses timing! -uses timing differences to localize sound

how does the body perceive a wide range of tastes (not just 5)?

hypothesis is based on integration in the brain: patterns of activity based on patterns/combinations of activated gustatory receptor cells

first order taste neuron

in the nuclei of three different cranial nerves, situated in medulla oblongata

photoreceptor cell layer

include rods and cones, sensory receptors that detect light and convert it into receptor potentials

is cell membrane an insulator or conductor?

insulator

thalamus

integrating center and relay station for sensory and motor information

medulla oblongata (medulla)

involuntary functions, control heart rate, breathing, sense blood pressure, sense toxins in blood and will stimulate vomit reflex

what molecules are impermeable to cell membrane?

ions, large uncharged polar molecules

define selective permeability

know what can pass the cell membrane and what cannot

cell body

largest part of a typical neuron; contains the nucleus and much of the cytoplasm

cerebrum

largest part of the brain, the "seat of intelligence", walnut appearance with gyri and sulci - 2 hemispheres - frontal lobe, parietal lobe, temporal lobe, occipital lobe, insula

hypothalamus

links nervous and endocrine systems, secretes hormones

neural stem cells

located in lateral ventricles, hippocampus and make new neurons throughout life!

stimulus intensity and duration

longer or stronger stimuli release more neurotransmitter -intensity encoded by frequency of action potentials

neurogenesis

making of new neurons -drives CNS, PNS development -limited in adult brain...but does occur!

types of sensory receptors

mechanoreceptor, thermoreceptor, photoreceptor, chemoreceptor, nociceptor

define graded potential

membrane potential changes that vary in amplitude depending on the stimulus ✺ typically occur on dendrites or the cell body ✺ stronger stimuli affect more membrane proteins and cause graded potentials of higher amplitude ✺ summation: graded potentials can add up when stimuli happen close together - mechanical and ligand-gated channels - location, amplitude, distance traveled, depolarize, hyperpolarize - summation, no refractory period - local current flow, decremental nature

brain stem

most ancestral, primitive part of brain - midbrain, pons, medulla, reticular formation

convergence

movement of the two eyes so that both are directed toward the object being viewed, for example, tracking a pencil moving toward your eyes -the nearer the object, the greater the degree of convergence needed to maintain binocular vision; coordinated action of the extrinsic eye muscles brings about convergence

white matter

myelinated axons

reticular formation

netlike white and gray matter within brain stem that regulates arousal from sleep, consciousness (awake state), muscle tone and posture, pain modulation

bipolar cell

neurons that convey signals from photoreceptors to ganglion cells

bipolar cell layer

neurons that convey signals from photoreceptors to ganglion cells

ganglion cell layer

neurons that generate action potentials in response to signals from bipolar cells

simple sensory neuron

neurons with free nerve endings; they may have myelinated or unmyelinated axons -want it for sensing acute heat -no other. supporting architecture associated with dendrites

what molecules are highly permeable to cell membrane?

nonpolar molecules

olfactory transduction

odorant ➞ G protein ➞ activate adenylyl cyclase in plasma membrane to produce cAMP from ATP ➞ cAMP opens cation channel ➞ Na+ and Ca++ enter ➞ receptor potential ➞ action potential

chemoreception

olfactory and gustatory

temporal lobe

olfactory cortex, auditory cortex, auditory association area

olfactory pathway to the brain

olfactory receptor cell in olfactory epithelium ➞ cranial nerve (I) ➞ synapse with mitral cell at glomerulus in olfactory bulb ➞ olfactory tract ➞ to a) olfactory cortex ➞ cerebral cortex and b) limbic system -each mitral cell receives inputs from one type of olfactory receptor cell

macula in otolith organs

otoliths, otolithic membrane, hair cell, stereocilia, tip link proteins, mechanically gated K+ channels -heavy crystals dragged by gravity; drags goopy membrane, causes deformation of stereocilia --> mechanical changes --> electrical changes

structure of rod and cone photoreceptor cells

outer segment, discs, inner segment, synaptic terminal mechanism: photopigments absorb light energy; their consequent structural change triggers signal transduction events that cause release of neurotransmitter

define referred pain

pain that is felt at a site remote from the place of origin -occurs because both somatic sensory and visceral sensory neurons often converge on second-order neurons of the same ascending pathway to the brain -since the brain is more accustomed to receiving sensory input from somatic sensory neurons than from visceral sensory neurons, it may incorrectly interpret pain from a visceral organ as having a somatic origin

olfactory bulb

parts of brain containing glomeruli that contain axons of olfactory receptor cells that converge onto mitral cells (second order neurons of olfactory pathway)

define frequency

pitch

phototransduction

process by which light energy is converted into a receptor potential in the outer segment of a photoreceptor ✦ rods are sensitive in low light and release neurotransmitter in that condition! light ➔ isomerizes cis-retinal ➔ trans-retinal separates from photopigment on the disc ➔ this activates a G protein on the disc membrane ➔ G protein triggers graded potentials that cause neurotransmitter release via Ca++ entry ➔ bipolar cell experiences graded potentials ➔ ganglion cell has action potential

astrocytes in BBB

processes press against capillaries to promote and maintain tight junctions with their secretions

microvilli

projections that increase the cell's surface area - project from each gustatory receptor cell to the tongue's surface through the taste pore

supporting cells of olfactory system

provide physical support to the olfactory receptor cells and help detoxify chemicals that come in contact with olfactory epithelium

suppression of pain sensations

provision of drugs -analgesic: drug that causes analgesia, pain relief that occurs without affecting other modalities of sensation or consciousness (aspirin, ibuprofen) -anesthetic: drug that causes anesthesia, absence of all modalities of sensations, including pain sensations; general anesthetic is a drug that affects the entire body and results in loss of consciousness, local anesthetic is a drug that affects only a small area of the body and does not result in loss of consciousness (novocaine, lidocaine)

metabotropic receptors

receptors that are associated with signal proteins and G proteins -signal is transduced by a second messenger: SLOWER RESPONSE

ionotropic receptors

receptors that are coupled to ion channels and affect the neuron by causing those channels to open -FASTER RESPONSE

hyposmia

reduced ability to smell; aging contributes to this as there is a gradual loss of olfactory receptor cells coupled with their slower rate of replacement as we age

pons

relay station between cerebrum and cerebellum; coordinate breathing with medulla

direction of visual processing

retina, optic nerves, optic chiasm, optic tracts, lateral geniculate bodies, optic radiations, visual cortex

semicircular canals (contains ducts)

rotational acceleration, deceleration -3 at right angles to each other -enlarged chamber of duct = ampulla that contains a sensory structure, the crista

5 unique gustatory receptor cells

salty, sour, sweet, bitter, umami (savory) - found in all the taste buds: all tastes can be detected in all tongue areas

cerebellum

second largest part of brain; coordinates movement

pituitary gland

secretes hormones that affect other glands and organs

pineal gland

secretes melatonin to regulate circadian rhythm

inner ear

semicircular canal, vestibule, cochlea, oval window, round window, labyrinth, lymph, tectorial membrane, basilar membrane, cochlear duct, organ of Corti with inner and outer hair cells, vestibulocochlear (VIII) cranial nerve ✦ series of cavities; hearing, equilibrium

nociceptor

sensitive to stimuli that damage, we perceive it as pain

4 attributes of sensory coding

sensory coding: how the CNS tells the difference among all the input stimuli - modality, definition of labeled line - location, definition of acuity ➣ 2-point discrimination ➣ timing ➣ lateral inhibition - intensity - duration

parietal lobe

sensory cortex, sensory association area

3 types of neurons

sensory neuron, interneuron, motor neuron

olfactory receptor cells

sensory neurons that respond to olfactory stimuli ✬ nonmotile cilia extend from dendrite of olfactory receptor cell, sites of olfactory transduction ✬ within the plasma membranes of olfactory cilia are olfactory receptor proteins that detect inhaled chemicals ✬ chemosensing property of olfactory cilia on olfactory receptor cells ✬ each olfactory receptor cell expresses 1 olfactory receptor protein all over its cilia ✬ approximately 400 unique olfactory receptor proteins and 400 unique olfactory receptor cells

taste buds

sensory organs in the mouth that contain the receptors for taste -each taste bud has all the types of gustatory cells; not restricted to one region

bony labyrinth

series of cavities in the temporal bone of the cranium; contains perilymph

3 types of sensory receptors

simple sensory neuron, complex sensory neuron, cell that synapses with sensory neurons

frontal lobe

skeletal muscle movement, motor cortex

pinna

skin-covered flap of cartilage located on each side of the head; collects sound waves and directs them into external auditory canal

what molecules are moderately permeable to cell membrane?

small uncharged polar molecules; cross via gaps as lipids move, # of gaps depends on the amount of cholesterol

what are the special senses?

smell, taste, vision, hearing, equilibrium

transmission of sound waves from air to fluid of ear

sound waves in auditory canal ➔ vibrate ear drum ➔ vibration of malleus/incus/stapes bones in air ➔ vibration transferred to membrane of the oval window ➔ creates motion/waves in lymph fluid of cochlea ➔ organ of Corti moves against tectorial membrane as vibration of basilar membrane occurs ➔ ultimately pressure release of the cochlea at the membrane of the round window

proprioceptive sensations

tell you where limbs are located and how they are moving when other senses are not involved ❊ 3 types: muscle spindles, tendon organs, joint kinesthetic receptors

thermoreceptor

temperature

factors under homeostatic control

temperature, pH, fluids, gases, nutrients, electrolytes, hormones

define "polarized state of cells"

the cell is POLARIZED because it exhibits a resting membrane potential

axon hillock

the cone-shaped area on the cell body from which the axon originates -where action potentials start

axon terminal

the endpoint of a neuron where neurotransmitters are stored

axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

horizontal cell

the laterally interconnecting neurons having cell bodies in the inner nuclear layer of the retina of vertebrate eyes -they help integrate and regulate the input from multiple photoreceptor cells

action potential propagation

the movement of an action potential along an axon; in myelinated axons, it occurs via saltatory conduction -continuous is like the space bar, saltatory like the tab key

organ of Corti

the organ of hearing, consisting of hair cells and supporting cells that rest on the basilar membrane and extend into the endolymph of the cochlear duct; aka spiral organ

somatosensory cortex

the sensory homunculus -this map depicts the relative proportion of the sensory receptors in the various parts of the body

axonal transport

the transportation of materials from the neuronal cell body to distant regions in the dendrites and axons, and from the axon terminals back to the cell body -ability to transmit excitability relies on AXONAL TRANSPORT: motor proteins kinesin and dynein hydrolyze ATP to "walk" along microtubules and move cargo (vesicles, organelle, other particles)

function of auditory ossicles

transmit and amplify vibrations from the tympanic membrane to oval window

true or false: a stroke that destroys function of the left visual cortex would destroy the ability to see the right visual field

true

gray matter

unmyelinated axons

equilibrium pathway to brain

vestibulocochlear (VIII) nerve ➔ cerebellum or brainstem ➔ cerebrum

basilar membrane regions

vibrate in high response to high, medium, or low frequency based on their membrane properties

sound transduction in the organ of Corti

vibration of basilar membrane ➔ hair cells move against the tectorial membrane and their stereocilia bend

occipital lobe

visual cortex and visual association area

body fluid maintenance is essential to homeostasis

★ body fluids are 50-60% of human total mass ★ intracellular fluid = ICF - inside cells, 2/3 of body fluids ★ extracellular fluid = ECF - outside cells 1. 80% interstitial: spaces between cells 2. 20% plasma: fluid in bloodstream; analysis of blood composition = litmus for homeostatic state - buffer between cells and the world ★ cell membrane = crucial to regulate homeostasis - serves as wall and possesses numerous gatekeeper functions

define feedforward system

★ controlled variable ➞ monitored by receptors ➞ control center ➞ effectors ➞ prepare for change ★ body is "looking forward," anticipatory sequence of events

nervous tissue

★ detect and respond to environment: convert stimuli to electrical and chemical signals

connective tissue

★ many forms: loose, dense, adipose, cartilage, bone, blood ★ functions: supports and protects organs, stores energy, insulation, transport gas

positive feedback loop

★ sequence of events that promotes/reinforces the change ★ example of cervix stretching and smooth muscle contractions during labor

muscle tissue

★ skeletal, smooth, cardiac ★ functions: body movement, heat, energy storage, organ movement, pump blood

negative feedback loop

★sequence of events that negates/reverses the change ★ example of elevated blood pressure

facts about olfactory pathways

☆ THALAMUS relay center is bypassed ☆ odors can evoke strong emotional responses and memories because action potentials are conducted to cerebral cortex and limbic system

facts about olfactory transduction

☆ threshold for detecting odors is low ☆ olfactory receptors are rapidly adapting sensory receptors (we "get used to" the smells around us)

protein component of cell membrane

✢ integral = pass all the way through ✢ peripheral ✢ glycoproteins

define peripheral nervous system (PNS)

✷ all nervous system outside the CNS ✷ cranial nerves connect brain to body: 12 pairs ✷ spinal nerves connect spinal cord to body: 31 pairs ✷ extensive networks of sensory receptors and wiring to effectors

define EFFERENT division

✷ somatic nervous system: connects to skeletal muscle ✷ autonomic nervous system: connects to all other tissues ➞ sympathetic: fight or flight activities ➞ parasympathetic: rest and digest activities ➞ enteric: gastrointestinal tract

photopigments in discs

✾ consist of opsin (4 different ones, each specific to 1 photoreceptor: 1 rod and 3 cone cells) and retinal (vitamin A derivative) complex ✾ light energy induces isomerization of retinal causes its dissociation from the opsin protein and apparent "bleaching" of the opsin


Ensembles d'études connexes

Audit Chapter 14 - Accounts Payable and Other Liabilities *

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Spinal Curvatures of the Vertebral Column (Figure 9.15)

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