UW -Madison Bio 151 Exam 3 - Physiology (Prof. Jeremiah Yang)

Surface Area

area outside of a cell on the plasma membrane

volume

three-dimensional space occupied by an object

SA/V

The ratio between surface area and volume showing the amound of surface a structure has relative to its size

diffusion

the random motion of molecules with net movement from high to low molecule concentration

cell

the simplest self-producing entity that can exist as an independent unit of life

tissue

collection of cells working together to form a specific function

connective tissue

Tissue with extensive cellular matrix and few cells underlying epithelial tissue as well as other places

epithelial tissue

tissue providing lining for all spaces inside/outside the body composed of closely packed cells

muscular tissue

tissue made of fibers that can shorten or contract to result in movement

nervous tissue

tissue in nerve nets of cnidarians and in the brain, spinal cord, and peripheral nervous system; takes in sensory information, processes it, then delivers the signal to target organs

organ

two or more tissues that combine and function together

organ system

group of organs with related functions

multicellular organism

organism composed of more than one cell with groups of cells differentiating to take on specialized functions

homeostasis

active regulation and maintenance of a stable internal physiological state in the face of a changing external environment

negative feedback

stimulus acting as a sensor that communicates with an effector to produce a response that opposes/inhibits the initial stimulus to maintain homeostasis

bulk transport

the movement of macromolecues into or out of the cell; Ex. exocytosis and endocytosis

form vs. function

shape or structure determines the capabilities or purposes of said structure

nerve

a bundle of axons from multiple nerve cells

neuron

nerve cell; the basic building block of the nervous system

cephalization

concentration of nervous system components at one end of the body

PNS (peripheral nervous system)

sensory and motor nerves, cranial and spinal nerves, neurons of autonomic nervous system, ganglia

CNS (central nervous system)

In vertebrates: brain and spinal cord

In invertebrates: centralized information processing ganglia

sensory neuron

neuron that receives or transmits information about an animal's environment or its internal physiological state

interneuron

neuron that processes information from sensory neurons and delivers it to motor neurons in different body regions

motor neuron

neuron signaling a muscle or glan to cause a response in the body

dendrite

fiberlike extension from the cell body of a neuron that receives signals from other nerve cells; the input end of a nerve cell

axon hilock

junction of the nerve cell body and its axon which initiates an action potential

axon

output end of a nerve cell that transmits signals away from the nerve's cell body

postsynaptic membrane

membrane that receives and binds neurotransmitters from the presynaptic cell and responds via depolarization or hyperpolarization

presynaptic membrane

membrane of an axon terminal facing the receiving cell, separated by the synaptic cleft

synapse

junction through which the axon terminal communicates with a neighboring cell

neurotransmitter

molecule conveying a signal from the end of an axon to the postsynaptic target cell, such as another neuron or a muscle fiber

membrane potential

the difference in electrical charge across the plasma membrane

action potential

brief membrane electrical signal transmitted from the nerve cell body along one or more axons

resting potential

imbalance of electrical charge that exists between the interior of electically excitable neurons and their surroundings

threshold potential

critical depolarization voltage of -55 mV required for an action potential

depolarization

increase in membrane potential from a negative resting potential to positive

repolarization

decrease in membrane potential from a positive resting potential to negative

voltage-gated sodium ion channels

ion membrane channels that open and close in responses to the changing membrane potential

inactivation gate

a gate that is open at rest but closes to stop allowing sodium ions into the cell, causing the membrane potential to stop rising

Na/K pump

a pump cycling through shape changes to maintain a negative membrane potential; pumps 3 sodium ions out, two potassium ions in

leaky ion channels

non-gated channels allowing ions to diffuse freely in/out of the cell

refractory period

period of inactivity following an action potential where inner membrane voltage falls below resting potential and then returns to it

glial cell

cell surrounding neurons to provide nutrition and physical support

node of Ranvier

periodic gap in myelin sheathe on the axon serving to facilitate the rapid conduction of nerve impulses

saltatory propagation

mocement of an action potential along a myelinated axon, 'jumping' from node to node

axon terminal

part of an axon that releases neurotransmitters to relay signals across a synapse

neurotransmitter storage vesicles (SVs)

vesicles clustered at presynaptic terminals and release neurotransmitters through exocytosis triggered by calcium

ligand-gated ion channel

receptor cite allowing the flow of ions across the plasma membrane when it is bound by ligand (Closed when unbound)

signal transduction pathway

outside molecules acting as a signal to activate a receptor which then transmits information through the cytoplasm

myelin sheathe

fatty insulating layers surrounding axons that speed up action potentials; produced by glial cells

astrocyte

type of glial cell regulating blood flow and providing mitochondria to neurons; also provides building blocks of neurotransmitters to fuel neuronal metabolism

EPSP (excitatory postsynaptic potential)

a positive change in the postsynaptic membrane potential

IPSP (inhibitory postsynaptic potential)

a negative change in the postsynaptic membrane potential

temporal summation

summation of postsynaptic potentials over time which determine whether the postysynaptic cell fires an action potential

spatial summation

the convergence of receptors onto a neighboring neuron increasing the firing rate proportionally to the number of signals received

afferent neurons

sensory neurons; nerve fibers responsible for bringing sensory information to the brain

efferent neurons

motor neurons; nerve fibers that carry signals from the brain to the peripheral nervous system to initiate an action

somatic responses

involuntary movement in response to external stimuli

autonomic responses

involuntary changes in internal processes in response to stimuli

sympathetic nervous system

autonomic nervous system subdivision arousing the body during fight or flight scenarios in which epinephrine is released to produce adrenaline and excite the body

parasympathetic nervous system

autonomic nervous system subdivision that calms the body down through the release of norepinephrine, returning the body to homeostasis to rest

motor endplate

postsynaptic region of a muscle cell where acetylcholine binds with receptors

acetylcholine (ACh)

neurotransmitter exciting nerves to regulate cardiac contractions and blood pressure

reciprocal inhibition

activation of opposing sets of muscles so that one is inhibited while the other is activated, allowing joint movement

sensory receptor cell

sensory neuron with specialized membranes in which receptor proteins are embedded

sensory organ

group of sensory receptors converting physical/chemical stimuli into nerve impulses processed by the nervous system and sent to the brain

sensory transduction

conversion of physical/chemical stimuli into nerve impulses

chemoreceptor

receptors responding to molecules that bind to specific protein receptors on the cell membrane of sensory receptors

mechanoreceptor

receptor responding to physical deformation of its membrane produced by touch, stretch, pressure, motion, or sound

photoreceptor

sensory receptors in the eye whose chemical properties are altered when light is absorbed

electroreceptor

sensory receptors for electric signals

thermoreceptor

sensory receptor responding to changes in themperature

nociceptor

sensory receptor for painful stimuli

lateral inhibition

enhancing a signal's strength locally but diminishing it peripherally by inhibiting adjacent cells' ability to receive it

g-protein coupled receptors

large and diverse group of membrane receptors taking in messages from light, peptides, lipids, sugars, proteins

g-protein

specialized proteins with the ability to bind GTP and GDP used to control transcription, motility, contractility, and secretion

olfactory epithelium

part of olfactory sensory system which passes smell to the brain; initial scent detector

olfactory sensory neuron

receptor neurons for odorant detection

tastebud

one of the sensory organs for taste

taste-sensory cell

cells making up taste buds(10-50) embedded in the epithelium of the tongue

microvilli

highly folded surfaces formed by fingerlike projections on the surface of epithelial cells

5 flavors (G* means g-protein coupled)

sweet-G, salty, sour, bitter-G, umami-G*

trigeminal nerve

fifth and largest cranial nerve providing sensation to the face; made up of opthalmic, maxillary, and mandibular nerves

stereocilia

non-motile cell-surface projections on hair cells whose movement causes a depolarization of the cell's membrane

statocyst

type of gravity detecting organ found in invertebrates

statolith

In plants: starch-filled root cap sensing gravity

In animals: dense particle freely moving with a statocyst allowing it to sense gravity

mechanoreceptor hair cell

specialized cell to detect movement

support cell

cell with the function of providing support to epithelial tissue

vestibular system

inner-ear system made up of two statocyst chambers and three semicircular canals

semicircular canals

fluid-filled tubes containing hair cells that sense angular motion of the head

malleus

small middle-ear bone helping to amplify waves that strike the tempanic membrane

incus

small middle-ear bone helping to amplify waves that strike the tympanic membrane

stapes

small middle-ear bone helping to amplify waves that strike the tympanic membrane; connects to oval window of cochlea

inner ear

made up of the cochlea and semicircular canals

vestibulocochlear nerve

The eighth pair of cranial nerves conveying sensory impulses from hearing and balance organs in the inner ear to the brain; connects to the vestibular and cochlear nerves

cochlea

coiled chamber within the skill containing hair cells that convert sound waves into electrical impulses and send 'em to the brain

eardrum

the tympanic membrane; separates outer ear from the middle ear

basilar membrane

main mechanical element of the inner ear

tectorial membrane

highly hydrated extracellular matric residing above the hair cells in the cochlea