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Physiology > Physiology Midterm > Flashcards

Physiology Midterm Flashcards

Chapters 1-9

1
Q

Physiology is defined as

A

the study of how animals work. This includes the structure and function of various parts, diversity of animals, and unifying themes.

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2
Q

Levels of biological organization

A

atoms, molecules, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and biosphere.

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3
Q

physiological subdisciplines

A

cell and molecular physiology, system physiology, organismal physiology, ecological physiology, integrative physiology.

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4
Q

Unifying themes of Physiology

A

A) physiological processes obey physical and chemical laws. B) physiological processes are usually regulated: regulation is a central theme in physiology. C) physiological phenotype is a product of genotype and phenotype. D) Genotype is the product of evolution.

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5
Q

Homeostasis

A

maintenance of internal constancy: negative feedback and positive feedback systems are frequently major players in homeostatic mechanisms.

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6
Q

Positive and negative feedback

A

Negative feedback works against body change. Examples are both body temperature and blood sugar regulation. Positive feedback works towards body change. An example is blood clotting.

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7
Q

Genotype

A

genetic makeup

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8
Q

Phenotype

A

morphology, physiology, and behavior

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9
Q

Physical properties of cell and tissue are linked to

A

structure and function

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10
Q

Molecular interactions are governed by

A

chemical laws both thermodynamic and kinetic

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11
Q

___ describe membrane function; especially excitable cells

A

Electric laws

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12
Q

___ influences physiological patterns

A

Body Size

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13
Q

Name 2 strategies for coping with changing conditions.

A

Conformers and Regulators

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14
Q

Conformers

A

Allow internal conditions to change with external conditions.

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15
Q

Regulators

A

Maintain relatively constant internal conditions regardless of external conditions.

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16
Q

Equilibrium

A

no net change or dissipation of energy.

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17
Q

Steady state

A

no net change, but continuous dissipation of energy or matter.

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18
Q

Life is a ___ process

A

Steady state. Animals continuously dissipate energy to keep away from equilibrium.

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19
Q

Phenotypic plasticity

A

single genotype generates more than one phenotype depending on environmental conditions.

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20
Q

____ contain a surprising amount of membrane

A

animal cells

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21
Q

The ___ is about 5-10nm thick: fluid-mosaic model

A

plasma membrane

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22
Q

Cell Membrane Structure

A

membrane, lipid, membrane lipid, membrane proteins

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23
Q

Membrane

A

lipid-protein assemblies held togethor in thin sheet by noncovalent bonds.

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24
Q

Lipid

A

Protein ratio varies greatly depending on membrane type: e.g. inner mitochondrial and myelin sheath

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25
Q

Membrane lipids

A

wide diversity of amphiathic lipids. most are phosolipids. Cholesterol is also present. Are distributed asymmetrically n the outer and inner layer of the bilayer.

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26
Q

Membrane proteins

A

can be more than half of the membrane mass. structural and regulatory functionss. two main types are Integral proteins and peripheral proteins

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27
Q

Lipid types

A

Phospholipids, sphingolipids, glycolipids, cholesterol

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28
Q

Phospholipids

A

make up lipid bi-layer. primarily phosphoglycerides

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29
Q

Sphingolipids

A

alter electrical properties

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30
Q

Glycolipids

A

communication between cells

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31
Q

Cholesterol

A

increase fluidity while decreasing permeability

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32
Q

Selectivity of membrane lipids

A

easy passage of water and no passage of proteins, glucose, and amino acids.

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33
Q

Integral membrane proteins

A

Tightly bound to the membrane. Embedded in bilayer or spanning the entire membrane.

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34
Q

Peripheral membrane proteins

A

weaker association with the lipid bilayer

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35
Q

Semipermeable membrane

A

allows molecules to cross while restricting others

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36
Q

Osmosis

A

the diffusion of water

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37
Q

Osmotic pressure

A

force associated with the diffusion of water

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38
Q

Osmolarity

A

the ability of a solution to induce water to diffuse across a membrane. determined by the concentration of dissolved particles.

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39
Q

Tonicity

A

the effect of a solution on cell volume.

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40
Q

hyperosmotic

A

higher osmolarity

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41
Q

hyposmotic

A

a solution with a lower osmolarity

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42
Q

isosmotic

A

osmolarities are the same

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43
Q

water diffuses from a ____ solution to a ____ solution

A

hyposmotic to hyperosmotic

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44
Q

hypertonic solution

A

water leaves the cell by osmosis. cells shrink

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45
Q

hypotonic

A

water enters the cell by osmosis. cells swell.

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46
Q

Isotonic

A

no net osmosis. cell neither shrink nor swell

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47
Q

Mode of membrane transport

A

passive diffusion

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48
Q

Passive diffusion

A

lipid-soluble molecules. no specific transporters are needed - molecules cross lipid bilayer. no energy needed. depends on concentration gradient - from high to low concentration. steeper gradient results in faster results. Example: water, steroid hormones and common medicines.

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49
Q

Facilitated Diffusion

A

hydrophilic molecules. protein transporter is needed. no energy needed. depends on concentration gradient - from high concentration to low concentration. Example: glucose, ions, amino acids.

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50
Q

Active transport

A

Protein transporter is needed. energy is required. molecules can be moved from low to high concentration.

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51
Q

Types of facilitated diffusion:

A

carrier proteins for small organic molecules such as glucose. ion channels: Na+, K+,Ca2+, Cl-.

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52
Q

Ion channels

A

a) a gate controls the opening and closing of the channel. b) three types: voltage-gated, ligand-gated, and mechanogated ion channels. c) defective channels -> severe diseases (Example: cystic fibrosis).

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53
Q

Two types of active transport

A

primary and secondary

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54
Q

Primary active transport

A

direct use of an exergonic reaction: ATP hydrolysis. Example: Na+/K+ ATPase (pump): found in the plasma membranes of every cell; spends one ATP for transporting 3 Na+ ions out of and 2 K+ ions into the cell; results in high K+ and low Na+ in the cytoplasm; results in a voltage difference across the membrane (membrane potential).

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55
Q

Secondary active transport

A

Use energy in electrochemical gradient of one molecule to drive another molecule against its gradient.

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56
Q

Antiport or exchange carrier

A

molecules move in opposite directions. secondary active transport. Example: Cl-/HCO3- exchanger in red blood cells.

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57
Q

Symport or cotransporter

A

molecules move in the same direction. secondary active transport. Example: Na+ gradient is used to efficiently drive glucose or amino acid import.

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58
Q

First law of thermodynamics

A

energy can be neither created nor destroyed; total energy in the universe remains constant.

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59
Q

Second law of thermodynamics

A

Disorder (entropy) in the universe, a closed system, is continuously increasing. no energy transfer is 100% efficient. Some energy dissipates as heat, random motion that contributes to entropy.

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60
Q

Potential energy

A

stored energy

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61
Q

Kinetic energy

A

energy of motion

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62
Q

Free energy

A

as energy increases, free energy decreases. G=H-TS where G is free energy, H is enthalpy (potential energy of the system), T is temperature in Kelvin, and S is entropy.

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63
Q

Dynamic Equilibrium

A

in a chemical reaction. rate of change is exactly the same in both directions. no work is done. delta G = 0.

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64
Q

Exergonic reactions

A

has negative delta G value -free energy decreases. are spontaneous - release free energy that can perform work.

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65
Q

Endergonic reactions

A

have positive delta G value - free energy increases. are not spontaneous.

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66
Q

coupled reaction

A

input of free energy is required to drive an endergonic reaction is supplied by an exergonic reaction. ATP hydrolysis is used to drive most cellular endergonic processes.

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67
Q

Adenosine triphosphate (ATP)

A

immediate energy currency of cells. donates energy of 3rd phosphate group. formed by phosphorylation of adenosine diphosphate (ADP) - endergonic process.

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68
Q

Catabolism

A

degradation of large complex molecules into smaller, simpler molecules. exergonic

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69
Q

Anabolism

A

synthesis of complex molecules from simpler molecules. endergonic

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70
Q

Phosphocreatine

A

alternative high-energy phosphate compound. creatine + ATP ADP + phosphoceatine. Reaction is reversible so phosphocreatine can be used to produced ATP when levels are low.

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71
Q

Routine ATP synthesis involves a symphony of events including ___, ____, and ____.

A

glycolysis, the TCA (Krebs) cycle. and the oxidative phosphorylation.

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72
Q

Equation of Glycolysis

A

Glucose + 2 ADP + 2 Pi + 2NAD+ —-> 2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O

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73
Q

Enzymes

A

are mediators of metabolism, responsible fro almost all of the reactions that occurs in a cell. required only in small amounts, have no effect of the delta G of the reaction. lower the activation energy. active and allosteric sites.

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74
Q

Metabolic rate

A

the rate of energy consumption. the rate which organisms convert chemical energy to heat and body work. the measurement is a basic indicator of important life processes and allows us to see effects of challenges to the animals, such as environmental changes, activity, sickness, drugs, etc.

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75
Q

Methods of measuring metabolic rate

A

a) direct calorimetry - measures the number of calories ingested by the animal. b) indirect calorimetry - measures the consumption of oxygen rather than dealing with calories.

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76
Q

Respiratory Quotient (RQ)

A

compares the volume of carbon dioxide produced to the volume of oxygen consumed by dividing the former by the latter. RQ = .7 for lipids, .8 for proteins, 1.0 for carbohydrates.

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77
Q

A ____ is necessary for metabolic rate

A

base line

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78
Q

Three items need consideration as to their effects of metabolic rate:

A

circadian rhythms, environmental fluctuations, physiological and genetic constitution of the animal, including its body mass.

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79
Q

Two ways to look at the effect of body size on metabolic rate

A

a) with increasing body size, the metabolic rate (O2 consumption) of the whole animal increases. b) with increasing body size, the metabolic rate per gram of animal decreases.

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80
Q

Competitive inhibition

A

the inhibitor competes with the normal substrate for the active site of the enzyme. a competetive inhibitor occupies the active site only temporarily.

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81
Q

Noncompetitive inhibition

A

the inhibitor binds with the enzyme at a site other than the active site, altering the shaoe of the enzyme and thereby inactivating it.

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82
Q

Multicellular organisms must ____ the activitie of the millions - trillions of cells that compose their bodies. This ____ requires that cells be able to communicate information to other cells, sometimes over great distances.

A

coordinate, coordination

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83
Q

Cell signaling

A

communication between cells

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84
Q

Types of cell signaling

A

direct (contact-dependent) signaling, autocrine and paracrine signaling, endocrine signaling, neuronal signaling.

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85
Q

Direct (contact-dependent) signaling

A

signaling cell and target cell connected by gap junctions. signal passed directly from one cell to another.

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86
Q

Indirect cell signaling

A

signalig cell releases chemical messenger. chemical messenger carried in extracellular fluid. Chemical messenger binds to a receptor on target cell. Activation of signaling transduction pathway. response in target cell.

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87
Q

Paracrine signaling

A

short distance indirect signaling. chemical messenger diffuses to nearby cell.

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88
Q

Autocrine signaling

A

short distance indirect signaling. chemical messenger diffuses back to signaling cell.

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89
Q

Endocrine signaling

A

long distance indirect signaling. chemical messenger tranported by circulatory system.

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90
Q

Nueronal signaling

A

long distance indirect signaling. electrical signal travels along a neuron and chemical messenger is released.

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91
Q

Types of chemical messengers (ligands)

A

peptides, steroids, biogenic amines, and nitric oxide (NO)

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92
Q

Gap junctions

A

specialized protein complexes create an aqueous pore between adjacent cells. movement of ions between cells, changes in membrane potential. chemical messengers can travel through (Example cAMP). Opening and closing can be regulated.

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93
Q

Peptide/ Protein Hormones

A

2-200 amino acids long. synthesized on the rough ER. stored in vesicles. secreted by exocytosis. hydrophilic (soluble in aqueous solutions). Bind to transmembrane receptors. Rapid effects on target cell.

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94
Q

Steroid Hormones

A

Derived from cholesterol. synthesized by smooth ER or mitochondria. three classes: mineralocoticoids (electrolyte balance), glucocorticoides (stress hormones), and reproductive hormones. hydrophobic. can diffuse through plasma membrane. cannot be stored in cell. must be synthesized on demand. transported to target ell by carrier proteins. slow effect on target cell (gene transcription).

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95
Q

Amine Hormones

A

Chemicals that posses amine group (-NH2). Some true hormones, some neurotransmitters, some both. Most hydrophylic (thyroid hormones are hydrophobic). Diverse effects.

96
Q

Gases - NO - Chemical Messengers

A

most act as paracrines

97
Q

Intracellular receptors

A

located inside of the cell and interact with hydrophobic chemical messengers.

98
Q

Transmembrane receptors

A

are located in cell plasma membrane and generally interact with hydrophilic chemical messengers.

99
Q

Types of transmembrane receptors

A

Ligand-gated ion channels, receptor-enzymes, G-protein-coupled receptors (GPCR)

100
Q

Ligand-gated ion channels

A

initiate a response in the target cell by changing the ion permeability of the membrane. only the correctly shaped ligand can bind to the recptor.

101
Q

Ligand mimics

A

Agonists- activate receptors. Antagonists- block receptors. many act as drugs or poisons.

102
Q

Receptor-enzymes

A

induce a response by activating or inactivating intracellular enzymes.

103
Q

G-protein-coupled receptors (GPCR)

A

send signals to an associated G protein, which then initiates a signal transduction pathway that causes a response in the target cell.

104
Q

Detailed GPCR explanation

A

a) G proteins are describes as heterotrimeric because they have 3 different polypeptide subunits (aplha, beta, gamma). b) when ligand binds to the GPCR on the surface of cells, the receptor is activated. c) activated receptor binds to G-protein-GDP. d) GDP is replaced by GTP. G-protein-GDP becomes G-protein-GTP. e) G-protein-GTP disassociates, G subunit alpha-GTP activated adenylyl cyclase (AC). f) Activated AC uses ATP to make cAMP. g) GTP of G subunit alpha-GTP hydrolyzes to form G subunit alpha-GDP. G subunit alpha-GDP disassociates from AC and reassociates with betagamma units to reform the inactive heterotrimeric G protein.

105
Q

Hypothalamus

A

1) integral to communication between nervous and endocrine systems. 2) produces hormones that act on pituitary gland.

106
Q

Pituitary glands have two portions

A

anterior and posterior

107
Q

Anterior pituitary

A

makes and secretes growth hormone, thyroid stimulating hormone, prolactin, follicle stimating hormone, luteinizing hormone, and adrenocorticotropic hormone.

108
Q

Posterior pituitary

A

does not synthesize hormones; it releases two hormones that are made in hypothalamus: oxytocin, antidiuretic hormone.

109
Q

ADH

A

acts to reduce urine production. goal is to retain more water.

110
Q

ADH release process

A

Osmoreceptors are located in the hypothalamus. they are sensitive to blood osmotic pressure. elevated osmotic pressure (low blood volume) triggers release of ADH. When ADH travels and reaches target cells (Kidney, frog’s skin), it binds to the receptor located in target cell. This turnes on G-protein coupled receptor signaling pathway.

111
Q

Movement is characteristic of animals. Movement is a cellular phenomenon that is dependent on the ____ and ____ that interact to form _____

A

cytoskeleton and motor proteins interact to form molecular motors.

112
Q

cells can use a ____ as an intracellular support, using reorganization of the _____ elements to change cell shape.

A

cytoskeleton.

113
Q

Cells use the ____ like a lever, pulling the cytoskeletoon backward.

A

motor protein

114
Q

cells can use the ______ as a track for motor proteins to move along, often carrying intracellular cargo.

A

cytoskeleton

115
Q

____ pull on the cytoskeleton, the cytoskeleton reorganizes and this generates movement.

A

Motor proteins

116
Q

Cytoskeleton

A

protein-based intracellular network

117
Q

motor proteins

A

enzymes that use energy from ATP to move

118
Q

Microtubules (MTs)

A

made of polymerized alpha and beta tubulin heterodiemers: (-) and (+) ends. Two motor proteins: kinesins and dyneins move along MTs.

119
Q

Kinesin

A

responsible for anterograde movement (to the + end of the microtubules)

120
Q

Dynein

A

move in a direction opposie to kinesin (to the - end of microtubules)

121
Q

Cilia

A

numerous wave-like motion. constructed of a precise arrangement of microtubules.

122
Q

Flagella

A

single or in pairs, whiplike movement. constructed ofa precise arrangement of microtubules.

123
Q

Microfilaments

A

made of the polymerization of globular actin subunits.

124
Q

___ use actin polymerization during fertilization

A

sperm.

125
Q

The motor protein, ____ moves along microfilaments

A

myosin

126
Q

Actin and myosin based movement can be described as the _____ model

A

sliding filament

127
Q

sliding filament model

A

Actin is the rope, myosin is your arm. Alternating cycle of grasp, pull, release. ATP binds causing myosin to detach. Myosin head extends and attaches to adjacent actin. Release of phosphate promotes power stroke. ADP is released.

128
Q

the ability of muscle to generate motion is often related to the ____ system. muscle contraction is transmitted to a mechanical system by an ______ or ______

A

skeletal, endoskeleton, exoskeleton

129
Q

exoskeleton

A

non-living skeleton (think cicada)

130
Q

endoskeleton

A

consists of living tissue

131
Q

skeletal system

A

supports and protects the body. transmits mechanical forces generated by muscles.

132
Q

hydraulic skeleton

A

fluid in closed body compartment transmits forces generated by contractile cells or muscle. Found in soft-bodied invertebrates.

133
Q

Two types of muscle cells

A

smooth and striated

134
Q

Smooth muscle fibers

A

lack cross-striations, are spindle-shaped, and have centrally located nucleus. they occur generally in flat sheets rather than in discrete bundles. the cells are very close to one another, an important point for electrical connection between the cells. Connected at gap junctions, contract in all dimensions, no sarcomeres, no t-tubules and minimal SR.

135
Q

Multiunit smooth muscle

A

Examples: iris, ciliary body, nictitating membrane, some muscle in blood vessels. Contraction cycles are short and they resemble skeletal muscle.

136
Q

Visceral smooth muscle

A

The more typical smooth muscle. it features slower contraction and relaxation, often contracting spontaneously, often lining a cavity and exerting pressure on the contents of that cavity.

137
Q

____ is involuntary and is innverted by both sympathetic and parasympathetic nerves usually that act antagonistically.

A

Smooth Muscle

138
Q

Smooth muscle contains ____, ____, and ___ but these proteins are less highly organized structurally than they are in skeletal and cardiac muscle. The sliding filament process probably applies in smooth muscle contraction.

A

actin, myosin, and tropomyosin

139
Q

Understanding that categorizing muscle types is somewhat imprecise, skeletal muscle is sometimes identified in at least two categories:

A

type I fibers and type II fibers.

140
Q

Type I fibers

A

tonic fibers; largely aerobic yeilding relatively slow contractions that are sustained; recieve multiple innervations and a fiber responds by a summation of small contractions.

141
Q

Type II fibers

A

twitch fibers; largely anaerobic during contraction; no graded response (that is, there is “all-or-none” contraction by an individual cell); there are other subdivisions of this category. This is the type of skeletal muscle more common in vertebrates.

142
Q

Specialized terminology associated with a muscle discussion

A

sarcolemma, sarcoplasm, sarcoplasm recticulum, sarcosomes.

143
Q

Myocytes

A

muscle cells. contractile unique to animals

144
Q

each skeletal muscle fiber is composed of parallel ____.

A

myofibrils

145
Q

Myofibrils are composed of ____ and _____ filaments.

A

myosin (thick) and actin (thin)

146
Q

The region of a sarcomere where thick filaments occur forms a dark region called the _____. It is the middle region of the sarcomere.

A

A (anisotropic) band

147
Q

The ____ appears lighter because there is no myosin there. It is located on either side of Z disk and occupied by thin filament

A

I (Isotropic) band

148
Q

The ____ (with an M line in the middle) appears lighter because there is no actin there.

A

H zone

149
Q

Z disks

A

form border of the sarcomere. Thin filaments attached to it extend from it towards the middle of sarcomere.

150
Q

sarcomeres are arranged into _____ - single, linear continuous stretch of interconnected sarcomeres. Extends the length of the muscle cell. have a parallel arrangement in the cell.

A

myofibrils

151
Q

During contraction we see this happen

A

a) the H zone becomes smaller or disappears. b) the A bands stay the same size. c) the I bands become smaller. d) the z lines get closer.

152
Q

“triad” in skeletal muscle

A

At various places the sarcolemma invaginates into the fiber and this membrane now comes in close contact with two pieces of the sarcoplasmic recticulum forming a “triad” of membranes. This is an important anatomic item in that it carries the muscle fiber action potential (impulse) into the interior of the cell.

153
Q

Sarcoplamic recticulum

A

Stores Ca2+ bound to protein sequestrin. Terminal cisternae increase storage.

154
Q

Transverse tubules (t-tubules)

A

Invaginations of sarolemma. Enhance penetration of action potential into myocyte.More developed in larger, faster twitching muscles. Less developed in cardiac muscle.

155
Q

Regulation of contraction

A

exitation-contracting coupling. depolarization of the muscle plasma membrane. Elevation of intracellular Ca2+. contraction - sliding filaments.

156
Q

Ca2+ allows myosin to bind to actin

A

At rest, cytoplasmic Ca2+ is low. Troponin-tropomyosin cover myosin binding sites on actin. Cytoplasmic Ca2+ increases. Ca2+ binds to TnC. Troponin-tropomyosin moves, exposing myosin-binding site on actin. Myosin binds to actin and cross-bridge cycle begins. Cycles continue as long as Ca2+ is present. Cell relaxes when sarcolemma repolarizes and intracellular Ca2+ returns to resting levels.

157
Q

isometric contraction

A

one in which the length of the fiber stays the same but the internal tension increases.

158
Q

isotonic contraction

A

one in which the length changes (shortens) but the tension stays the same.

159
Q

Recording of a single twitch of a muscle, though artificial from a normal standpoint, shows some important contraction characteristics. Those include the ___, ____, and ____

A

latent period, contraction period, and the relaxation period.

160
Q

Applying repeated stimulations befor relaxation can occur causes the contractions to pile on top of one another. This is also called ____.

A

Temporal summation.

161
Q

The starling principle

A

illustrates that, up to a point, pre-stretch/pre-loading of muscle yields a more forceful contraction.

162
Q

____ represent lose anatomic associations between cells and contribute to the functional syncytial nature of cardiac muscle.

A

Intercalated discs

163
Q

Noteable features of cardiac muscle

A

a) starling principle. b) the lack of a stable resting potential leading to spontaneous contractions. c) extended action potentials. d) a clear refractory period..

164
Q

an organism’s ability to survive and to maintain homeostasis depends largely on how effectively it detects and responds to ___ - changes in the environment. Most animals have a nervous system that, like a cmputer, takes in information, integrates it, and responds.

A

stimuli

165
Q

The nervouse system is composed mainly of two specialized types of cells __ and ___.

A

neurons and glial cells

166
Q

A typical neuron consists of

A

a cell body, dendrites, and an axon.

167
Q

In vertebrates, the axons of many neurons outside the central nervous system are surrounded by ___, glial cells that form an insulating covering called the myelin sheath.

A

Schwann cells

168
Q

___ is a whit, fatty material found in the plasma membranes of Schwann cells.

A

Myelin

169
Q

The _____ in a neuron is basically the same as the ___ in a muscle fiber. both are “excitable” cells.

A

electrical event

170
Q

Depolarization

A

membrane potential becomes less negative

171
Q

Repolarization

A

membrane potential returns to resting value

172
Q

Hyperpolarization

A

membrane potential becomes more negative than resting value.

173
Q

To account for the resting potential difference, we note the ___ and ___ and certain underlying membrane

A

intracellular and extracellular fluid ionic components

174
Q

The resting potential features these ionic characteristics:

A

in the intracellular fluid, K+ is the principle cation, there is some Na+, and the chief anion is mostly protein. In the extracellular fluid Na+ is the principle cation, there is some K+, and the chief anion is Cl-.

175
Q

Important characteristics underlying the resting potential include these items:

A

The membrane is impermeable to protein. In the resting neuron, the membrane is up to 100 times as permeable to K+ as to Na+. Na+ pumped out of the neuron cannot easily pass back into the cell, but K+ pumped into the neuron easily diffuse out. Therefore, the resting potential has been identified as K+ diffusion potential.

176
Q

Action potential

A

is a reversed polarity across the membrane. the neuron becomes more permeable to sodium ions. theres is also an increase in permeability to potassium ions that follows the sodium ion permeability increase. Therefore, it has been identified as a sodium ion diffusion potential.

177
Q

Threshold

A

represents the amount of disturbance that a resting potential can absorb before an action potential is generated.

178
Q

All or none responses

A

occurs or doesn’t occur all APs are same magnitude

179
Q

Absolute refractory period

A

coincides with the depolarization and repolarization phases. cell incapable of generating a new AP

180
Q

Relative refractory period

A

coincides with the after-hyperpolarization phase. more difficult to generate new AP

181
Q

Spatial summation

A

graded potentials from different sites influence the net change

182
Q

Temporal summation

A

graded potentials that occur at slightly different times influence net change.

183
Q

Synapse

A

a junction between a neuron and another neuorn or effector cell. consists of a presynaptic, the synaptic cleft, and a postsynaptic cell.

184
Q

neuromuscular junction

A

a specific type of synapse involving the terminal part of a motor axon and the sarcolemma of a nearby muscle fiber. At this junction, a neurotransmitter substance is released from the axon. it travels across the synapse and contacts the sarcolemma and acts as a stimulus. this is an example of a ligand-gated event. subsequent propagation of the action potential down the sarcolemma occurs by voltage-gated events.

185
Q

Electronic current spread

A

charge spreads along membrane

186
Q

regenerative cycle

A

ion entry -> electronic current spread -> triggering of AP

187
Q

self propagating

A

an AP triggers the next AP in adjacent areas of the membrane without degradation.

188
Q

____ conductance of action potentials is common in animals. In a few specialized situations, there is also __ conductance of action potentials. In these situations, the cell membranes of the adjacent cells are close enough that an action potential can be passed electrically from one to another via ion flow. These are typically bi-directional, in contrast to more typical chemical synapses that are one-way

A

chemical, electrical

189
Q

neurotransmitters

A

synthesized in neurons; released by presynaptic cell following depolarization; bind to postsynaptic receptor and cause an effect

190
Q

Acetylcholine (ACh)

A

causes post synaptic potential that is stimulatory to the skeletal muscle.

191
Q

Inhibitory neurotransmitters

A

cause hyperpolarization of the membrane - inhibitory postsynaptic potential (IPSP). Make postsynaptic cell less likely to generate an AP.

192
Q

Excitatory neurotransmitters

A

cause depolarization of membrane- excitatory postsynaptic potential (EPSP). make postsynaptic cell more likely to generate an AP.

193
Q

At any synapse the transmitter substance present must be ____.

A

Temporary.

194
Q

At the neuromuscular junction, ACh cannot just stay in the synaptic cleft; it is broken down by ____ in the synaptic space. This allows the receiver cell membrane to return to resting potential.

A

acetylcholine esterase (AChE)

195
Q

Organophosphate (OP)

A

insecticides that inhibit AChE activities. widely used to control insect pests.

196
Q

Two experimental manipulations allow us further insight into the neuromuscular junction.

A

a) compounds such as curare that stabilizes the sarcolemma. b)compounds such as nicotine and succinylcholine chloride that lead to persistent depolarization.

197
Q

____ are often classified as either ionotropic or metabotropic.

A

Neurotransmitter receptors

198
Q

Ionotropic receptors

A

are ligand-gated ion channels. Fast

199
Q

Metabotropic receptors

A

receptor changes shape. formation of second messenger. alters opening of ion channel. slow. may lead to long-term changes via other cellular functions.

200
Q

ACh receptors can be ____ or ___

A

ionotropic or metabotropic

201
Q

Two major classes of ACh receptors

A

the nicotinic and the mscarinic receptors.

202
Q

Receptor for ____ and _____ are termed the adrenergic receptors. In mammals, the great diversity of receptors ( alpha 1, alpha 2, beta 1, beta 2, etc) allows ___ and ____ to have opposing effects on different tissues, depending on the particular receptor that is present.

A

norepinephrine and epinephrine

203
Q

___ detect information about changes in the internal or external environment. They can be as simple as a single sensory neuron, or can involve complex sense organs, such as eyes, ears, and nose.

A

sensory receptors

204
Q

____ refer to cells that are specialized to detect incoming sensory stimuli. some ___ are themselves afferent neurons. Other ____ are epithelial cells that send a signal to a separate afferent neuron.

A

sensory receptors

205
Q

Based on the type of stimulus, there are

A

chemoreceptors, mechanoreceptors, photoreceptors, thermoreceptors, electroreceptors, and magnetoreceptors

206
Q

generator potential

A

sensory receptor is also the primary afferent neuron. change in membrane potential spreads along membrane.

207
Q

receptor potential

A

sensory receptor is separate from the afferent neuron. change in membrane potential triggers release of neurotransmitter.

208
Q

Most cells can sense incoming ___, and animals have many types of _____ that they use to sense their external and internal chemical environments, such as olfaction and gustation.

A

chemical signals, chemoreceptors

209
Q

__ are neurons with cilia. __ are G-protein-coupled receptors

A

olfactory receptor cells, odorant receptor proteins.

210
Q

Odorant receptors

A

a)binding of odorant to an ororant receptor protein causes a conformation change, which sends a signal to an associated G-protein, Golf. b) activated Golf activates adenylate cyclase (AC). c) Activated AC uses ATP to make cAMP. d) cAMP opens cAMP-gated Na+ and Ca2+ channels. e) Na+ and Ca2+ enter the cell, causing a generator potential. f) the Ca2+ also opens Ca2+ activated Cl- channels, causing Cl- to leave the cell, increasing depolarization. g) the generator potential opens voltage-gated Na+ channels, triggering action potentials.

211
Q

Taste receptors are ____ that release neurotransmitters

A

epithelial cells

212
Q

Taste Receptor cells

A

a) Na+ from salty food enters through a Na+ channel, causing a recptor potential. b) the resulting depolarization opens voltage gated Ca2+ channels. c) the influx of causes neurotransmitter release. d) the releasing of neurotransmitter would trigger an action potential in the afferent neuron.

213
Q

____consists of the entire field that can be seen without moving the eyes. In humans, about half of the neurons coming from each eye cross over each other in the optic chiasm

A

Visual field

214
Q

The ___ is one of the body’s homeostatic control systems, helping to regulate physiological processes and coordinate behavior.

A

nervous system

215
Q

Associated with the nervous system

A

afferent neurons, efferent neurons, and interneurons. Central nervous system and peripheral nervous system.

216
Q

In vertebrates, ___ is composed of the brain and spinal cord. The___ is protected by the meninges.

A

Central nervous system (CNS)

217
Q

The ____ are made of one or more protective layers of connective tissues.

A

meninges

218
Q

Within the meninges, the brain and spinal cord float in a plasma-like fluid called

A

cerebrospinal fluid (CSF)

219
Q

The CNS is also physiologically separated from the rest of the body by the ____, which is formed by tight junctions between the endothelial cells lining the brain capillaries.

A

blood-brain barrier

220
Q

The _____ prevents materials from leaking out of the bloodstream and into the CNS via paracellular patways

A

blood-brain barrier

221
Q

The efferent branch of the PNS can be divided into two main divisions:

A

the autonomic division and the somatic motor division

222
Q

Autonomic nervous system

A

is involved in the homeostatic regulation of most physiological function, including heart rate, blood pressure, breathing, and many other processes that are critical for life.

223
Q

Somatic motor pathways

A

control skeletal muscles, which are usually under conscious control

224
Q

The autonomic division can be differentiated into three branches

A

the sympathetic, parasympathetic, and enteric nervous systems.

225
Q

Sympathetic nervous system

A

is most active during periods of stress or physical activity, and is referred as “fight or flight” system.

226
Q

Parasympathetic nervous system

A

is most active during periods of rest, and is referred as “resting and digesting” system.

227
Q

Enteric system

A

is mainly involed in digestion.

228
Q

The CNS regulates the _____

A

autonomic nervous system

229
Q

three mechanisms for regulating autonomic function

A

dual innervation, antagonistic action, basal tone

230
Q

dual innervation

A

most organs recieve input from both systems

231
Q

antagonistic action

A

one system stimulates while other inhibits

232
Q

basal tone

A

even under resting conditions autonomic neurons carry APs

233
Q

three parts of the meninges

A

dura mater, arachnoid mater, pia mater

234
Q

spinal nerves

A

branch from spinal cord. enter and exit between adjacent vertebrae. named based on region of vertebral column from which they emerge. mixed nerves.

235
Q

Cranial nerves

A

exit directly from skull. 13 pairs. some afferent, some efferent, some mixed.

Physiology (1 decks)

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