UNIT 1 Vocabulary Flashcards
1
Q
enzyme
A
Molecule that speeds up a particular chemical reaction in the body
2
Q
intra-
A
within
3
Q
extra-
A
outside
4
Q
endo-
A
inside, inner
5
Q
exo-
A
outside, outer
6
Q
secretion
A
Release to a cell’s exterior, on appropriate stimulation, of substances produced by the cell
7
Q
exocrine glands
A
Glands that secrete through ducts to the outside of the body or into a cavity that communicates with the outside
8
Q
endocrine glands
A
Ductless glands that secrete hormones into the blood
9
Q
intracellular fluid (ICF)
A
The fluid collectively contained within all of the body cells
10
Q
extracellular fluid (ECF)
A
All the fluid outside the cells of the body; consists of interstitial fluid and plasma
11
Q
interstitial fluid
A
The portion of the extracellular fluid that surrounds and bathes all the body cells
12
Q
plasma
A
The liquid portion of the blood
13
Q
stem cells
A
Relatively undifferentiated cells that can give rise to highly differentiated, specialized cells while at the same time making new stem cells
14
Q
variables
A
Something that varies or have no fixed quantitative value
15
Q
homeostasis
A
Maintenance by the highly coordinated, regulated actions of the body systems or relatively stable chemical and physical conditions in the internal fluid environment that bathes the body cells
16
Q
homeostatic control system
A
A regulatory system that includes a sensor, integrator, and effectors that work together to bring about a corrective adjustment that opposes an original deviation from a normal set point
17
Q
intrinsic
A
Situated within or belonging solely to the organ or body part on which it acts
18
Q
extrinsic
A
Originating from the outside, external
19
Q
feedback
A
A response that occurs after a change has been detected; may be negative feedback or positive feedback
20
Q
negative feedback
A
A regulatory mechanism in which a change in a controlled variable triggers a response that opposes the change, thus maintaining a relatively steady set point for the regulated factor
21
Q
positive feedback
A
A regulatory mechanism in which the input and the output in a control system continue to enhance each other so that the controlled variable is progressively moved farther from a steady state
22
Q
feedforward
A
An element or pathway within a control system which passes a controlling signal from a source in its external environment, often a command signal from an external operator, to a load elsewhere in its external environment
23
Q
sensor
A
The component of a control system that monitors the magnitude of the controlled variable
24
Q
set point
A
The desired level at which homeostatic control mechanisms maintain a controlled variable
25
integrator
A region that determines efferent output based on processing of afferent input; also called a control center
26
effector
The component of a control system that accomplishes the output commanded by the integrator
27
plasma (cell) membrane
A protein-studded lipid bilayer that encloses each cell, separating it from the extracellular fluid
28
nucleus (of a cell)
A distinct spherical structure, usually located near the center of a cell, that contains the cell's genetic material, deoxyribonucleic acid (DNA)
29
membranous organelle
Have a phospholipid bilayer and typically some sort of hollow center. This allows separation of elements in space and time and for more specialization. The organelles include the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, vacuoles, lysosomes, mitochondria, and, in plants, chloroplasts
30
nonmembranous organelle
Do not have a phospholipid bilayer so they are in direct contact with the cytosol
31
vesicles
A small, intracellular, fluid-filled, membrane enclosed sac
32
exocytosis
Fusion of a membrane-enlosed intracellular vesicle with the plasma membrane, followed by the opening of the vesicle and the emptying of its contents to the outside
33
endocytosis
Internalization of extracellular material within a cell as a result of the plasma membrane forming a pouch that contains the extracellular material, then sealing at the surface of the pouch to form an endocytic vesicle
34
hydrolysis
The digestion of a nutrient molecule by the addition of water at the bond cite
35
phagocytosis
A type of endocytosis in which large, multimolecular, solid particles are engulfed by a cell
36
oxidation
A chemical reaction in which there is the loss of electrons or gain (or increase in the proportion) of oxygen, hence, resulting in an increase in oxidation state by a molecule, atom or ion
37
reduction
Any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent.The act of reducing complexity.The change in the atomic composition of an atom / molecule by adding hydrogen, losing oxygen, or gaining electrons
38
oxidative phosphorylation
The entire process of mitochondrial biochemical reactions that uses oxygen to extract energy from the nutrients in food and tranforms it into ATP, producing CO2 and H2O in the process; includes the electron transport system and chemiosmosis
39
aerobic
Referring to condition in which oxygen is available
40
anaerobic
Referring to a condition in which oxygen is not present
41
transport proteins (carrier molecules)
Membrane proteins that, by undergoing reversible changes in shape so that specific binding sites are alternatively exposed at either side of the membrane, can bind with and transfer particular substances unable to cross the plasma membrane on their own
42
receptor
Membrane protein that binds with a specific extracellular chemical messenger, bringing about membrane and intracellular events that alter the activity of the particular cell
43
junctions
Cell junctions consist of multiprotein complexes that provide contact between neighboring cells or between a cell and the extracellular matrix. They also build up the paracellular barrier of epithelia and control the paracellular transport. Cell junctions are especially abundant in epithelial tissues
44
passive (force)
A force that does not require the expenditure of cellular energy to accomplish transport of a substance across the plasma membrane
45
active (force)
A force that requires the expenditure of cellular energy (ATP) in the transport of a substance across the plasma membrane
46
solution
A type of homogenous mixture in which the particles of one or more substances (the solute) are distributed uniformly throughout another substance (the solvent)
47
solvent
A liquid in which substances (or solutes) are dissolved forming a solution
48
solute
A component of a solution: in a solution, the dissolving substance is called a solvent whereas the dissolved substance is called a solute
49
concentration
The measure of the amount of a sub-component (especially solute) in a solution
50
gradient
The rate at which a physical quantity, such as temperature or pressure, changes relative to change in a given variable, especially distance. A series of progressively increasing or decreasing differences in the growth rate, metabolism, or physiological activity of a cell, an organ, or an organism
51
concentration (chemical) gradient
A difference in concentration of a particular substance between two adjacent areas
52
electrical gradient
A difference in electrical charge between two adjacent areas
53
diffusion
Random collisions and intermingling of molecules as a result of their continuous thermally induced random motion
54
osmosis
Movement of water across a membrane down its own concentration gradient toward the area of higher solute concentration
55
isotonic (solution)
Having the same concentration of solutes as the blood: an isotonic saline solution
56
hypotonic (solution)
A solution with osmolarity less than that of normal body fluids; more dilute than normal
57
hypertonic (solution)
A solution with osmolarity greater than that of normal body fluids; more concentrated than normal
58
primary active transport
A carrier-mediated transport system in which energy is directly required to operate the carrier and move the transported substance against its concentration gradient
59
secondary active transport
A transport mechanism in which a carrier molecule for glucose or an amino acid is driven by a Na+ concentration gradient established by the energy-dependant Na+-K+ pump to transfer the glucose or amino acid uphill without directly expending energy to operate the carrier
60
cotransporter (symporter)
The form of secondary active transport in which the driving ion and transported solute move in the same direction across the plasma membrane
61
antiporter (countertranporter)
The form of secondary active transport in which the driving ion and transported solute move in opposite directions across the plasma membranes
62
vesicular transport
Movement of large molecules or multimolecular materials into or out of the cell within a vesicle, as in endo- or exocytosis
63
membrane potential
A separation of charges across the membrane; a slight excess of negative charges lined up along the inside of the plasma membrane and separated from a slight excess of positive charges on the outside
64
millivolt (mV)
One thousandth of a volt
65
leak channels
Unregulated, ungated channels that are open all the time
66
voltage gated channels
Channels in the plasma membrane that open or close in response to changes in the membrane potential
67
chemically gated channels
Channels in the plasma membrane that open or close in response to the binding of a specific chemical messenger with a membrane receptor site that is in close association with the channel
68
net (as in net movement or net gain)
The difference between the opposing movements of two types of molecules in a solution
69
polarization
The state of having membrane potential
70
depolarization
A reduction in membrane potential from resting potential; movement in the potential from resting toward 0 mV
71
repolarization
Return of a membrane potential to resting potential following a depolarization
72
hyperpolarization
An increase in membrane potential from resting potential; potential becomes even more negative than resting potential
73
action potential
A brief, rapid, large change in membrane potential that serves as a long distance electrical signal in an excitable cell
74
graded potential
A local change in membrane potential that occurs in varying grades of magnitude; serves as a short distance signal in excitable tissues
75
neuron
A nerve cell specialized to initiate, propagate, and transmit electrical signals, typically consisting of a cell body, dendrites, and an axon
76
cell body
The portion of the neuron that houses the nucleus and organelles
77
dendrites
Projections from the surface of a neuon's cell body that carry signals toward the cell body
78
axon (nerve fiber)
A single, elongated tubular extension of a neuron that conducts potentials away from the cell body; also known as a nerve fiber
79
axon hillock
The first portion of a neuronal axon plus the region of the cell body from which the axon leaves; the site of action potential initiation in most neurons
80
synaptic terminal (axon terminal, etc.)
The branched endings of a neural axon, which release a neurotransmitter that influences target cells in close association with the axon terminals
81
refractory period (absolute, relative)
The time period when a recently activated patch of membrane is refractory (unresponsive) to further stimulation, which prevents the action potential from spreading backward into the area through which it has just passed and ensures the unidirectional propagation of the action potential away from the initial site of activation
82
myelin
An insulative lipid covering that surrounds myelinated nerve fibers at regular intervals along the axon's length; each patch of myelin is formed by a separate myelin-forming cell that wraps itself jelly-roll fashion around the neuronal axon
83
nodes (of Ranvier)
The portions of a myelinated neuronal axon between the segments of insulative myelin; the axonal regions where the axonal membrane is exposed to the ECF and membrane potential exists
84
synapse
The specialized junction between two neurons where an action potential in the presynaptic neuron influences the membrane potential of the postsynaptic neuron, typically by releasing a chemical messenger that diffuses across the small cleft between the neurons
85
EPSP
Excitatory Postsynaptic Potential; a small depolarization of the postsynaptic membrane in response to neurotransmitter binding, bringing the membrane closer to threshold
86
IPSP
Inhibitory Postsynaptic Potential; A small hyperpolarization of the postsynaptic membrane in response to neurotransmitter binding, thereby moving the membrane farther from threshold
87
temporal summation
The summing of several postsynaptic potentials that occur very close together in time because of successive firing of the single presynaptic neuron
88
neurotransmitter
The chemical messenger released from the axon terminal of a neuron in response to an action potential that influences another neuron or an effector with which the neuron is anatomically linked
89
neuropeptide
A potent appetite stimulator secreted by the hypothalamic arcuate nucleus
90
hormone
A long-distance chemical mediator secreted by an endocrine gland into the blood, which transports it to its target cells
91
excitatory (synapse)
A synapse in which the nerve impulse in a presynaptic cell tend to increase the probability of the postsynaptic cell to fire an action potential
92
inhibitory (synapse)
A synapse in which the nerve impulse in a presynaptic cell results in a reduced likelihood for a postsynaptic cell to fire an action potential
93
convergence
The converging of many presynaptic terminals from thousands of other neurons on a single neuronal cell body and its dendrites so that activity in the single neuron is influenced by the activity of many other neurons
94
divergence
The diverging, or branching, of a neuron's axon terminals so that the activity in this single neuron influences the many other cells with which its terminals synapse
95
signal molecules
An extracellular chemical messenger that initiates signal transduction in a cell
96
target cell
The cells that a particular extracellular chemical messenger, such as a hormone or a neurotransmitter, influences
97
receptor (in membrane)
Membrane protein that binds with a specific extracellular chemical messenger, bringing about membrane and intracellular events that alter the activity of the particular cell
98
receptor-channel
A type of receptor that is an integral part of a channel that opens (or closes) on binding with an extracellular messenger
99
ligand
Molecule which produces a signal by binding to a site on a target protein
100
lipophilic
Ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene
101
hydrophilic
Having an affinity for water; capable of interacting with water through hydrogen bonding
102
spatial summation
The summing of several post-synaptic potentials arising from the simultaneous activation of several excitatory (or several inhibitory) synapses
