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1

Microtrabecula rLattice

Mesh of inerlinked filaments through cytoplasm that connect inner layer of plasma membrane

2

3 DNA functions

Assemble structural/enzymatic proteins
Enzymes control structures and regulation of metabolism
Perpuetuate genetic blueprint

3

3 nucleotide components

nitrogenous base
5 carbon sugar ring
phosphate group

4

polynucleotide

sugar-phosphate backbone with bases projecting out

5

4 nucleotide bases

double ringed adenine and guanine
single ringed cytosine and thymine

6

What holds together DNA strands

Hydrogen bonds between bases

7

2 base pairs

A-T
G-C

8

Genes

Stretch of DNA codign for synthesis of polypeptide

9

Chromosome

Packed form of DNA, each has unique set of genes

10

Somatic cells

46 chromomsomes (diploid) sorted into 23 pairs

11

Homologous chromosomes

Matched pair, one from dad and one from mom

12

Germ cells

have one chromosome from homologous pair, 23 (haploid)

13

2 proteins that bind with DNA

Histones: Form beads on a string, pack DNA into chromosomes
Non-histones: gene regulation

14

Chromatin

DNA and associated proteins--> working form for protein synthesis

15

DNA replication

stands unzip by breaking H bonds with enzymes
complimentary base pairing with exposed bases
2 double stranded DNA with one old and one new strand

16

DNA transcription

When not replicating, complementary base pairing of free RNA nucleotides with DNA counterparts on exposed gene
RNA strand that is complementary to DNA strnad

17

RNA

link between DNA in nucleus and ribosomes in cytoplasm
5 carbon sugar ring is ribose
Contains uracil instead of thymine
Single strnaded and not self-replicating

18

messenger RNA

transcribes protein instructions
DNA uncoils and exposes a gene sequence with a strat and stop signal

19

Translation

mRNA delivers protein code to ribosomes

20

Ribosomal RNA

ribosome component that reads mRNA and translates it to AA sequence

21

transfer RNA

transfers AA in cytosol to designated site in protein sequence
20 AA used but only 4 based used for code

22

Triplet code

Sequences of 3 bases in DNA chain that code for an AA
64 codes--> 61 AA and 3 stp signals

23

Codon

Complementary code word transcribed onto mrna
TAC/AUG is start

24

Ribosome

enxymes and energy to link AAs
made of 2 subunits that come together for synthesis

25

protein synthesis steps

mRNA attaches to small subunit by leader sequence preceding start codon
small unit binds to large unit
tRNA brings free AAs to proper codon
Initiation, elongation, termination

26

TrNA

Single stranded in T shape, open stem binds to AA
20 types each only bind to a specific AA
Bind to mRNA at ribosome and release AA to specific codon

27

Anti codon

Loop end of trna has sequence of 3 exposed bases that are complementary to mRNA sequence

28

Initiation

Charged trna with anticodon for start codon binds to site on mrna

29

Elongation

Second charged trna with next anticodon binds to site--> ribosome can only accomodate 2 trnas
- peptide bonds form between AAs
- trna breaks from its AA, 2nd trna has 2 AA
-ribosome moves along mRNA by 2 bases
- 3rd TRNA takes vacated spot and binds all3 AAs

30

Termination

Ribosome reaches stop codon in mRNA, polypeptide released, protein folded into final form, ribosome dissociates

31

synthesis energy

requires splitting 4 phosphate bonds
2 to charge trna
1 to bind TRNa to ribosome/mrna
1 to move ribsome forward a codon

32

Polyribosomes

Many copies of protein producd from single mRNA
Ribosome moves forward, second ribosome attaches to starting point

33

gene regulatory proteins

repress genes for specific proteins so they only make products theyre supposed to like hemoglobin in RBCs

34

gene signalling factors

Brign differential gene activity among various cells to accomplish a task

35

2 omponents of cell division

Mitosis-- nuclear division
Cytokinesis-- cytoplasmic division

36

Mitosis

complete set of genetic material distibuted into 2 daughter cells

37

Interphase

Periord between divisions for DNA replication and cell growth

38

Prophase

Chromatin condenses into sister chromatids (condensed duplicate strands joined at centromere)
Centriole pair divides and daughters move to opposite ends between mitotic spindle
Membrane on nucleus breaks down

39

Centriole

Cylindrical structures forming mitotic spindle

40

Metaphase

Nuclear membrane dissaperas, 46 chromosomes line down middle of cells (pairs of sister chromatids)
Spindle fibres attach to centromere

41

Anaphase

Centromeres split, sister chromatids become identical chromosomes
Molecular motors pull chromosomes on mitotic fibres
92 chromosomes total--> 46 on each pole

42

Telophase

Cytoplasm divides by actin contractile ring
Spindle fibres dissemble and chromosomes uncoil into chromatin
Nuclear membranes form

43

Meiosis

Nuclear division of germ cells, each get hapolid number
Diploid germ cell--> 1 chromosome replication followed by 2 nuclear divisions to make 4 haploid germ cells

44

Meiosis 1 Prophase

Homologous pairs of chromosomes line up side by side in a tetrad
Crossing over of material between non-sister chromatids in tetrad

45

Tetrad

4 sister chromatids with 2 identical chromatids in each member of pair

46

Meiosis 1 metaphase

23 terads line at equator

47

Meiosis 1 anaphase

Sister chromatids joined at centromere seperate ad move to opposite poles in random assortments

48

Meiosis 1 Telophase

Cell divides in 2 with 23 chromosomes each (sister chromatids)

49

Meiosis 2

23 unpaired chromosomes line at euator, centromeres split, sister chromatids seperate into independant chromosomes at opposite poles

50

Zygote

haploid egg and sperm form a diploid fertilize egg

51

Point mutation

Any change in DNA sequence where base is added, substituted or deleted during replication
- can be fixed by repiar enzymes

52

Oncogenes

Induce uncontrolled cell proliferation
caused by mutations in DNA segements called protooncogenes

53

Plasma membrane

Layer of lipids and proteins and carbhydrates selectively permits passage of materials
Joins cells to form tissues and organs

54

Trilaminar structure

PM has 2 dark layers seperated by light middle layer

55

Phospholipids

most abundant PM material--> polar head of negative phosphate, 2 non polar fatty acid tails
- Hydrophillic head, hydrophobic tail

56

Lipid bilayer

In water, hydrophob tails bury themselves in centre, heads line both sides

57

Cholesterol in PM

tucked between phospholipid molecules to prevent fatty acid tails from crystallizing and reducing fluidity

58

Fluid mosaic model

Membrane fluidity and patetrn of floating proteins

59

Glycoproteins

small carbs coat outer PM like antennas bound to proteins

60

3 PM functions

bilayer is barrier to diffusion
Proteins perform specalized fucntions
Carbs are self-recognition markers for cell-cell interaction

61

7 membrane protein functions

Channels
Carrier molecules
Docking marker acceptors
membrane bound enzymes
recpetor sites
cell adhesion molecules (CAM)
selfrecognize in cell-cell interactions

62

Channels

Span membrane, water soluble materials pass through without touching hydrophobic interior
Highly selective--> only for small ions and specific chemical arrangements

63

Docking marker acceptors

Inner membrane surface, bind with docking markers on secretory vesicles

64

Cell adhesion molecules

Protrude from outer PM, form hooks that grab connective tissue or other cells
- cadherins: interlock adjacent cells
Integrens: span PM, link to extracellular envionmment and to intracellular cytoskeleton

65

Protein self recognition

Unique sugar chains are trademark for cells of its own kind, important in tissue groth and embryo development

66

CF cause

flawed CFTR protein which regulates chloride channels leads to impermeability of CL, salt accumulates in fluid
Antibiotic defensin doesnt work in salty environment

67

Interstitial fluid

fibrous proteins embedded in gel of carbohydrates, holds cells together
pathway for diffusion of nutrients and wastes

68

3 proteins in interstitial fluid

collagen-- tensile strength
elastin-- recoil
fibronectin-- cell adhesion, reduction causes cancer

69

extracellular matrix

secreted by local cells especiallu connective tissues and fibroblasts

70

Cell junctions

CAMs hold cells in close proximity

71

Desmosomes

Anchor cells closely but not touching
Composed of plaques on inner surface, and glycoprotein filaments that attach to plaques on both sides
Most abundant in stretchy tissues

72

Tight junction

Directly binds cells in a seal, abundant in epithelial
Junction proteins fuse on either side
Impermeable, prevents leaks

73

Gap junction

cells linked by small tunnels amde of connexons (6 protein subunit)
Communictaing junction for passage of small water soluble ions and signalling molecules
Abundant in smooth and cardiac muscle for electric activity

74

lipid soluble materials

Uncharged, poalr molecules like O2, CO2 and fatty acids

75

unassisted membrane transport

molecules/ions penetrate PM driven by diffusion on concentration or electrical gradient

76

Passive diffusion

Moelcules frequently collide in heat energy, greater concentration creates more collision
Diffusion is uniform spreading of molecules over time

77

Concentration gradient

Differenc ein concentration between 2 adjacent areas, net movement from high to low

78

Net diffusion

Differenc ebetween 2 opposing movements until areas reach equilibrium

79

Ficks law of diffusion

Influences on rate
- Magnitude of conc. grad. --> greater diff = faster rate
-P of membrane to substance--> more P= faster rate
- SA of membrane
Molecular weight of subsatnce--> lighter goes rapidly
Distance of diffusion

80

Passive ion diffusion

electrical gradient promotes ions to move towards opposite charge--> only occurs if ions can permeate membrane

81

Eletrochemical gradient

Electrical and concentration gradients act on a specific ion

82

Osmosis

Areas with unequal solute concentration move from high water concentration to lower (from low solute concentration to high)

83

Aquaporins

Protein channel for pasage of water

84

permeable solutes

Can move in opposite direction of water on its own concentration gradient

85

impermeable solutes

stay on its own side but water still moves so cell volume shrinks/ swells

86

Hydrostatic pressure

Increases as volume expands in compartment which opposes osmosis --> psushes water backwards

87

Osmotic pressure

Measure of tendency for water to move into solution due to concentration of non-penetrating solutes and water--> water keeps moving until hydrostatic pressure = osmotic pressure
- high concentration of non-penetrating solute exerts greater osmotic pressure

88

Tonicity

Effect a solution has on cell volume when solution surrounds a cell--> determined by concentration of non-penetrating solutes because penetrating solutes dont effect osmosis

89

Isotonic solution

Same concentration of non-penetrating solutes as normal cells --> no water enters or leaves by osmosis and volume is constant

90

Hypotonic solution

Below normal concentration of non-penetrating solute causes water to enter by osmosis and cell to swell

91

Hypertonic solution

Above normal concentration of non penetrating solute causes cell to shrink

92

Asissted membrane transport

Large, poorly lipid soluble molecules are too big for channels

93

Carrier mediated transport

small-water soluble substances. Proteins span membrane, can flip between ECF/ICF. Molecule binds to binding site, carrier flips to other side, bound molecule detaches and carrier reverts to original shape

94

3 characteristics of materials trnasported by carriers

Specificity: Carrier for specific material, cells vary in carriers
Saturation: Limited number of binding sites--> Transport maximum is limiting factor in transport
Competition: closely related compounds fight for a ride

95

2 forms of carrier mediated transport

Facilitated diffusion
Active transport

96

Facilitated diffusion

Carrier assists transport from low to high concentration, no energy required
Polar, not lipid soluble, too big (glucose)--> higher con. in blood than tissues
- carrier picks it up, flips with gradient from high to low

97

Active transport

Requires energy to move material against con gradienrt
- uptake iodine into gland with high con.
ATP varies affinity of binding site for passnger on low concentration side--> phosphorlyation causes flip
- dephosphorylation reduces affinity for passnger so its released
(H ion pump in lumen)

98

Growth hormone

Secreted by anterior pituitary to increase protein synthesis in skeletal muscles

99

Na/K bump

Transfer both at the same time in opposite directions--> Na into ECF and K into ICF at basolateral membrane
Phosphorylation inside increases affinity for Na, dephosphorylation outside for K
Brings out 3 Na, 2 K in

100

3 functions of Na/K pump

Establish concentration gradient for electrical signals
Regulate cell volume
Secondary active transport

101

Secondary active transport

Energy used by NA/K pump is energy source for glucose transport and AA in kidney and intestinal cells with uphill concentrations with blood
- different than faiclitated diffusion carriers

102

Co transport carriers

Luminal carriers in intestine and kidney cells. 2 binding sites for Na and a molecule. Establishment of Na gradient by primary active transport drives secondary mechanism .
Both bind, Na is moving downhill, glucose uphill
Na released due to low concentration, glucose for reduced affinity

103

Vesicular Transport

Moving large polar molecules in a membrane bound vesicle requires energy

104

Endocytosis

PM surrounds cell to be ingested, pinches off vesicle to fuse with lysosome, or to move through cell and release by exocytosis

105

2 purposes of exocytosis

Allow secretion of large polar molecules
Cell can add specific components to membrane like carriers, channels and receptors

106

Membrane potential

Energy from seperated opposite charges can be harnessed to perform work (milivolts). Attraction of opposite charges makes ions line up on eiher side of membrane

107

Excitable tissues

Nerve and muscle cells can make rapid, transient changes to membrane potential

108

Resting membrane potential

Na/K + and A- intracellular proteins responsible
Na concentrated in ECF with low P
K concentrated in ICF with high P
A concentrated in ICF with no P
- Na and K passively flow through channels, electrical gradient always towards negatuve side

109

NA/K pump and membrane potential

80% made indirectly by passive diffusion on con grad.
20% made by pumping more Na in, K out making the outside more positive

110

K equilibrium potential (hypothetical alone)

2 forces--> elec grad attracting it to negative ineterior
- chem grad pushing it out
increases potential and K leaves cell until chemical gradient opposes electrical
EK = -90 mV potential

111

Nernst equation

Equilibrium for an ion of different concentrations across a membrane
E= 61 log Co/ CI
- measures MP that counterbalances concentraton gradient

112

Na equilibrium potential

Con gradient pushes it inwards and electrical gradient attrcats it in --> EP is +60
Greater P means that ion drives membrane potential closer to its own equilibrium potential

113

Resting nerve cell potential

-70mV--> doesnt counterbalance con grad for K so it passively leaks out through channels
- Na doesn tleak inwards due to low P

114

Chloride movement at resting potential

principle ECF anion, Eq potential is -70mV , exact same as resting potential
inward concentration gradient opposed by outward concentration gradient of NA/K
Cl doesnt effect potential, potential effects it

115

Polarization

Charges spread across PM so it has potential
Polarized anytime potential is greater than 0

116

Depolarization

Reduction in MP so that fewer charges are seperated at resting potential
MP moves closer to 0, becomes more positive

117

Repolarization

Membrane returns to resting potential after being depolarized
MP becomes more negative

118

Hyperpolarization

Increase in magnitude of resting potential
- 80MV

119

Depolarization ion movement

Net inward flow of psotive ions causes inside to become less negative
Caused by changes in P

120

Triggers for permability change

Change in electric field in vicinity
Chemical messenger interacts with surface receptor
Stimulus like sound waves
SPontanous change due to imbalance in leak/pump cycle

121

Ions carrying electric charge

Water soluble and must pass into membrane through channels

122

Leak channel

Open all the time allowing leakage of specific ion

123

Gated channels

Gates permit/deny ion passage by changing #D shape
- Voltage, chemical, mechanical and thermal

124

2 forms of electrical signals

Graded potnetial (short distance)
Action potential (long distance)

125

Graded potential

Local change in MP in varying magnitudes. Produced by opening of chemcial and mechanical gated channels in excitable membrane
Na gates open allowing inward flow on gradient, results in depolarization of region

126

Graded potential magnitude

related to magnitude of triggering event. More channels open, more positive charge entering, larger graded potential

127

Active area

temporarily depolarized region that is more positive than inactive areas

128

Current

ions flow between active and resting regions on either side of membrane in direction of positive charge flow

129

inside current

positive charges flow away from depolarized active region, potential now differs so current flows on either side and depolarization spreads

130

outside current

positive charges flow towards more negative active region

131

Resistance

Hindrance to electrical charge movement
conductors have low resistance (iCF and ECF)
insulators like lipids are resistant

132

Where is current lost

When ions leak through uninsulated parts of membrane through channels
Magnitude of local current is decremental
Graded potentials have limited distance for signals

133

Action potential

Brief, rapid, large 100MV change in MP wher epotential reverses so inside becomes more positive than outside
Non-deceremental so it goes far

134

What triggers action potential

Triggering event or graded potnetial that depolarizes adjacent regions where AP can take place

135

Threshold point

Slow depolarization until critical level between -50/-55 MV when upward deflection brings potential to +30
Rapid reversal makes inside posiitve before rapidly reversing to hyperpolarization, then resting potential

136

AP charge pattern

Threshold (depolarization)
Peak (hyperolarization)
Resting

137

Graded vs action potential duration

Graded is variable
AP is always 1msec in nerve

138

Overshoot

Portion of AP where potential is reversed to 0-+30
Called a spike

139

All or nothing

If threshold isnt reached by intial depolarization then AP wont occur

140

Ion with greatest contribution to resting potential

K--> more permeable than Na
AP changes permeability of Na and K allowign rapid reflux
Triggers opening of voltage gated Na, K channels

141

Voltage gated Na and K channels

Charged proteins surrounded by electrical field that can distort channel structure when proteins are attracted or repelled

142

Na voltage gated channel

Activation gate: guards channel like a door
Inactivation gate: ball and chain of AAs closes when ball binds to receptor
Both gates must be open for Na to pass

143

3 conformations of Na channel

Closed but can open--> activation closed, inactive open
Open--> both gates open
Closed and incapable--> active open, inactive closed

144

Voltage gated channels at resting potnetial

All voltage gated channels are closed except Nas inactivation gate . No passage of ions

145

K permeability at resting

50-75x more P than Na due to leak channels

146

Channels during depolarization

Both Na gates open favor Na to move in, induces positive feedback cycle so more channels open

147

Channels at threshold

Expolsive increase in Na permeability (600x) causes Na to rush in until potential reaches 30mV
At peak Na channels close and P drops

148

Why do na channels close at peak

activation gates triggered to open in response to depolarization, initates channel closing
- conformation change that opens channels allows inactivation gate to bind shut slowly

149

K channels

Start to slowly open at peak of AP allowing K efflux

150

3 AP events at threshold

rapid opening of Na activation gates
Slow closing of Na inactivation gate
Slow opening of K gate makes potential plummet back to resting by increasing K P to 300x

151

K at the peak

Positive inside repels K on gradient to outside, restores negative potential

152

AP rising and falling phases

Rising to threshold caused by Na influx
Falling to rest caused by K efflux

153

Neuron components

Cell body
Dendrites
Axon

154

Cell body

nucleus, organelles, form input zone with dendrites where APs are triggered by incoming messenger

155

Dendrites

Protrude from cell body, recieve signals from other neurons
Protein receptors to bind with messengers

156

Axon

ELongated tube conducts APs away from cell body. Collaterals are side branches

157

Axon hillock

Emerges from soma, trigger zone with gretaest density of voltage gated Na channels

158

Axon terminal

Releases chemical messengers during AP--> outpu zone

159

Why do places with graded potnetials not start APs

few voltage gated Na channels
Can trigger adjacent areas to depolarize and make an AP

160

2 methods of propogation

Salatory
Contiguous

161

Contiguous conduction

Spread of AP along every patch of membrane down axon. Axon hillock is at peak of AP, rest of axon must be depolarized. Local current causes adjacent areas to reach threshold where Na gates are thrown open. Original active area brought back to rest by K efflux. Triggers new APs in self-perpetuating cycle

162

Refractory period

Stops axons from sending signals in both directions. Normal events cant trigger AP in region that just underwent one

163

Absolute refractory period

Area undergoing AP cant produce another one no matter what. Na channels are open. Can trigger to open again until resting potential is reached. Na gates are closed but capable

164

Relative refractory period

Second AP can be made by a really strong trigger. Caused by lingering inactivation of Na channels, and slowness to close of K channels. Less than normal Na entry following an AP and really big hyperolarizing leak of K ensures one-way propogation, and number of APs on axon in given time

165

All or none law

Excitable membrane either gives maximal AP spreading throughout membrane, or it doesnt make one at all

166

Strength of AP

strong stimulus chnages frequency of AP but not magnitude

167

Contiguous conduction fibres

Unmyelinated so each AP triggers new AP in next segment
Salatory is myelinated fibres which is faster

168

Myelinated fibre

80% lipid, 20% protein, insulator so that water soluble ions for current cant pass through

169

Oligodendrocyte

Myelin forming cells wrap around axons in brainand CNS

170

Schwann cells

Myelin in nerves between CNS and PNS

171

Nodes of ranvier

area between myelinated regions where axon is bare and exposed to ECF. Where voltage gated Na channels congregate--> unmyelinated regions have high concentrations of channels down length

172

Length between nodes

1mm, short enough for loca current between active and inactive nodes

173

Salatory conduction

Myelinated fibre AP where it jumps from node to node. 50x faster as AP is only regenrated at nodes

174

How does myeliantion conserve energy

Eenrgy consuming Na/K pump restores fewer ions after AP

175

Magnitude of current flow depends on

Deifference in potential between charged regions
Resistance to charge movemetn between 2 regions

176

Fibre diamter increases

Resistance to local curent decreases--> large myelinated fibres for urgent messages

177

PNS nerve regeneration

Portion furthest from cell body degenerates, schwann cells phagocytize debris
Portion connected to cell body grows and moves forward

178

Regeneration tube

Schwann cells guide regeernating nerve to proper destination by chemical guides

179

CNS regeneration

Oligodendrocytes make proteins that inhibit growth. to stabilize structure after development. Degeneration and scarring

180

Antibody nogo

Block nerve growth inhibitors to fix spinal cord

181

Peripheral nerve graft

introduce schwann cells to grow nerves

182

olfactory ensheathing glia transplant

olfactory neurons regularly replaced, can be used to fix nerves

183

Multipotent precursor cells

Alter fate in response to environemt they are introduced to

184

Pluripotent

More than one outcome, found in umbilical cord blood

185

Multipotent

Limited number of specializations, proliferate into undifferentiated state to form cell types of particular tissue

186

Synapse

Junction between axon terminal of one neurons and dendrite of another--> dendrites have thousands of synapses

187

Presynaptic neuron

Conduct AP towards synapse, ends in swelling called synaptic knob which has NT vesicles

188

Post synaptic neuron

Propogates APaway from synapse-- seperated from presynapse by synaptic cleft

189

Synaptic membrane Na/K channels

Tricked ya there arent any. Pre alters post by chemical means

190

Synapse events

AP causes change in potential at axon terminal, stimulates opening of Ca voltage channels
Ca inwards gradient causes influx into knob
Ca triggers NT release by exocytosis

191

Subsynaptic membrane

Portion of psot synaptic membrane under the knob, NTs diffuse and bind to receptors here
NT binding causes change in Ca P in post synapse

192

Excitatory synapse

NT binding opens non specific channels in subsynapse allowing Na and K passage--> increase P of both

193

Excitatory Post Synaptic Potential process

Rest: electrochemical grad favors Na in, K out
P change makes alot of Na to move in causing small depolarization in post synapse, brings it closer to threshold
One excitary synapse has too few channels t make it to theshold--> further excitation causes EPSP

194

Inhibitory Synapse

Different NT binding increase subsynapse to increase P of K or Cl bringing small hyperpolarization

195

Inhibitory post synaptic potential

Pk increase makes K leave, Cl to move in on gradient
- brings membrane further from potential
- inhibited to bring AP because inside is more negative

196

Are EPSP/IPSP voltage gated

no they are chemically gated

197

Synaptic delay

0.5 msec delay between P in presynapse and signal to post synapse by either EPSP or IPSP because complex pathways take time

198

Permeability change

continues as long as NT is bound to receptor, must be removed or inactivated, taken back up by presynapse

199

EPSP/IPSP graded potential

varying magnitude, no refractory period and can be summed up

200

Grand postsynaptic potnetial

Total of all EPSP and IPSP occuring at same time through temporal or spatial summation

201

Temporal summation

2 APs from same synapse fire at the same time in close succession causing first to depolarize and second to bring post synapse to potential. Rapid, repetitive excitation from single input

202

Spatial summation

Simulataneous activation of 2 or more EPSP from different inputs added together brings post synapse to threshold , or IPSP bring it further away

203

Where is threshold potential lowest

axon hillock--> more voltage gated Na channels are more repsonsive to chnages in potential

204

Classic NTs

Small, rapid acting molecules trigger ion channels to open to bring potential changes in post synapse
Packaged in cytosol of axon temrinal

205

Neuropeptides

Larger 2-40 AA chains made in ER/GC and brought to axon terminal on micortubules. Bring slower, prolonged repsonses

206

Dense-core vesicles

large packages present in axon terminal hold neuropeptides, released by Ca induced exocytosis

207

Neuromodulators

Messengers dont form IPSP/EPSP, depress/enhance synapse action to bring long term changes

208

Presynaptic inhibition/facilitation

Third neuron chnages synaptic effectivenss along with neuromodulators. Binds to presynapse, releaes NT that binds to presynaptic receptors and alters the amount of NT it releases when triggered by AP

209

What causes release of NT

Ca entry magnitude effects how much NT is released

210

Drugs effect on synaptic activity

Modify Nt interaction with post synapse
Influence Nt reuptake or destruction
Replace deficient Nt with a substitute

211

Cocaine

Blocks reuptake of dopamine in presynapse , competitively binds with dopamine reuptake transporter so it stays in cleft longer

212

Parkinsons

Deficiency of dopamine in basal nuclei controlling movement, causes muscular rigidity. Treted with dopamine precursor that cna cross BBB

213

tetanus toxin

Prevents release of inhibitory GABA from presynapse of skeletal muscle nerves causing spasms

214

Strychine

Competes with inhibitory glycine at post synapse

215

Convergence

Neuron has many other neurons synapsing on it so it influences and is influenced by any others

216

Divergence

Branching of axon temrinals so one cell synapses with many other cells. Neurons are presynaptic to one group and post synaptic to another

217

3 forms of intercellular communciation

Gap junctions
MArkers on surface membranes allow direct link
Extracellular chemical messengers most common

218

Paracrines

Local messengers exerting effects on immediate environment by diffusion, dont enter blood and and are rapidly inactivated by enzymes

219

Hormones

Long range, secreted into blood, exert effects on target cells with proper binding sites

220

Neurohormones

Released into blood by neurosecretory neurons on an electric signal

221

Signal transduction

Instructions from extracellular messengers conveyed to target cell interior. Lipid soluble (steroids) bind with receptors inside, water soluble (hormones) bind to receptors on outside and trigger second messenger

222

Fast synapse

fucntion when NT changes conformation of chemically gated channels and alter P and ion influx

223

Slow synapse

Responses mediated by second messengers when messenger is water soluble

224

Endocrinology

Homeostatic chemical adjustments by hormones secreted into blood by adrenal glands

225

2 hormone groups by solubility

Hydrophillic
Lipophillic

226

Hydrophillic hormones

water soluble, low lipid solubility
Peptide horomones made of amino acids

227

Catecholamines

Hydrophillic hormones derived from AA tyrosine and secreted by adrenal medulla (epinephrine)

228

Hormone solubility determines

Way it is processed by endocrine cell
Way it is transported in blood
Mechanism it exerts on target cell

229

Processing hydrophillic peptide horomones

segregated from intracellular proteins by membranse. Stimulus makes it fuse to PM and release contents

230

Preprohormones

Precursor proteins synthesized by rough ER, move to GC in vesicle where it is pruned into active protein

231

Processing lipohillic steroid hormone

produced by steroidgenic cells, cholesterol is precursor
Steroids not stored, diffuse through PM into blood
Cholesterol is stored and effects rate of synthesis

232

Difference betwene processing lipochillic vs hydrophillic

Hydrophillic dependant on rlease of precursor
Lipophillic dependant on rate of synthesis

233

Hydrophillic transport

Simply dissolved into plamsa

234

Lipophillic transport

Ciculate in blood and cant dissolve into watery plasma, only small unbaound portion is biologcally active. circulate as free horomones

235

Catecholamine tranport

1/2 are free hromones, 1/2 are bound to plamsa protein albumin

236

Hydrophillic/catecholamine receptors

Receptors on outer membrane. Activate second messengers. Alter protein channels to cahneg ion flow

237

Lipophillic recpetors

pass through PM and bind to receptors inside target cell. Activate specific genes to cause formation of new intracelluar proteins

238

2 second messenger pathways for hydrophillic hormones

CAMP
Ca

239

cAMP second messenger pathwyas

1st messenger binds, activates adenyl cyclase in cytoplasm
Adenyl cyclase converts ATP into cAMp by cleaving off 2 phosphates
CAMP activates protein kinase A to produce effects

240

protein kinase A

phosphorylates intracellular protein t chnage shape
Altered protein produces response

241

G protein

Intermediary between recpetor and adenyl cyclase found on inner PM --> alpha, beta, gamma subunits
- Alpha subunit breaks off to reach cAMP
-after repsonse, alpha subunit rejoins g complex and Camp is inactivated

242

Ca Second messenger

1st messenger binds, G proteins activate phopholipase C on inner membrane
Enzyme breaks down PIP2 in lipid tails
Produces DAG and IP3
IP3 mobilizes Ca in cytosol
Ca activates calmodulin which inhibits/enhances protein to bring desired response

243

How does Ca influence Camp pathwya

Calmodulin regulates adenyl cyclase
Protein kinase A can phosphorylate and change activity in Ca carriers

244

2nd messenger Amplification

Messenger binding activates mant adenyl cyclases, each activate many CAMP, each acts on one protein kinase A which activates many enzymes to make many products
**low hormone concentration can make big repsosne

245

Lipophillic hormones protein syntheis

Free hormones diffuse through PM, bind with rceptor
Recpetor has regiosn to bind with horomone and DNA
DNA binding turns on gene to make a protein
Transcribed onto RNA
RNA binds to ribosome to make protein

246

Horomone Response element

Attachment site for DNA, different for each hormone

247

Nonn genomic steroid receptors

Steroids bind to receptors in membrane and dont alter gene activity

248

Gaseous NTs

small, freely permeable, endogenously generated, mimicked by exogenous application, mediated by second messenger--> NO,CO, hydrogen sulphide

249

Nitric oxide

Free radical messenger that is also toxic.
Endogenously made from O, highly reactive and easily diffuses
Causes vasodilation

250

Which hormones act faster

Second messengers faster than those that synthesize proteins

251

Amblyopia

Lazy eye doesnt get appropriate stimulation in development, use it or lose it

252

PNS

nerve fibres carry info to periphery--. split into afferent and efferent

253

Afferent PNS

Carries info gathered from environemtn to deliver to CNS

254

Efferent PNS

Instructions transmitted form CNS to effectors (muscles and glands)
Split into Somatic and Autonomic NS

255

Somatic NS

Fibres of motor neurons supplying skeletal mscles

256

Autonomic NS

fibres innervating smooth muscle, cardiac muscle and glands
Seperated into sympathetic and parasympatthetic

257

3 classes of neurons

Afferent
Efferent
Interneurons

258

Sensory recpetor

Peripheral end of afferent neuron that generates APs in rsponse to stimuli

259

Afferent neurons

Shaped differently. Cell body inside spinal cord is devoid of dendrites and presynaptic inputs
APs are initated at receptor and propogated to spinal cord

260

Efferent neurons

Cell bodies originate in CNS, presynaptic inputs converge on them to influence output t effectors
Fibres leave CNs to go to muscles and glands

261

Autonomic nerve pathway

2 neuron chain betwene CNS and effector organ

262

Interneurons

99%--> lie entirely in CNS betwene afferent and efferent neurons to integrate peripheral responses
Responsible for mind--> emotions, memory, intellect

263

Glial cells

90% of cells in CNS take 1/2 the colume
Do not conduct nerve impulses, they maintain homeostasis and talk to neurons by chemical messengers
CNS connective tissue

264

Glial cell role

Maintain composition of extracellular environment
Modulate synaptic function for learning and memory

265

Glioma

Brain tumourbecause glialcellsdont lose ability to divide

266

Meningoma

Originate in meninges, protective membrane covering CNS

267

4 glial cell types in CNS

astrocytes
oligodendrocytes
microglia
ependymal cells

268

7 astrocyte functions (most abundant)

glue to hold neurons together
Sacaffolding to guide neurons in deveopment
Make small blood vessels become BBB
Repair brain injury and neural scar formation
Take up/degrade gluatmate and GABA
Take up excess K from ECF when AP activity exceeds ability of NA/K pump
Enhance synapse formation and modify transmission

269

Excess K in ECF

reduce neuronal membrane to threshold and cause seizures

270

4 ways astrocytes chnage synaptic transmission

Gap junctions to other neurons
Astrocytes have glutamate receptors
ATP release causes calcium influx
strocytes release other NTs

271

Microglia

Immune cells of CNS defend brain as phagocytes
Release growth factor
Excess chemical release involved in neurogenerative disease

272

Ependymal cells

Line internal cavities of brain and spinal cord
Form CSF and move it around with cili
Form neural stem cells to tur into neurons and glial cells

273

Ventricles

4 chambers continuous with central canal that goes through spinal cord

274

4 features of CNs protection

cranium
Meninges
Cerebrospinal fluid
Bloodbrain barrier

275

Meninges

Dura mater-- 2 inelastic outer layers
Arachnoid mater-- highly vascularized, sub space has CSF
Pia mater: highly vascular, adhered to brain and spinal cord

276

Dural sinuses

Blood filled regions between layers of dura mater
CSF re enters blood through arachnoid villi

277

Venous sinuses

In dura mater, contain blood from bain to return to heart,

278

CSF

Circulates through ventricles and exits through 4th
same density as brain
Exchnage materials between neural cells and interstitial fluid

279

Choroid plexus

In ventricle cavities, formed by pia mater dipping into ependymal cell pockets
Forms CSF that is lower in K, higher in Na

280

CSF volume

125-150mL replaced 3x a day

281

Hydrocephalus

Excess CSFcauses water on the brain, pressure causes damage

282

BBB

consists of endothelial cells which limits exchanges across capillaries which are joined by tight junctions
lipid solubles dissolve through, the rest is selectively transported

283

which structure isnt subject to BBB

hypothalamus needs blood samles, no tight junctions

284

Neuroglobin

O2 binding protein in brain--> brain only uses glucose for fuel

285

Stroke

Cerebrovascular accident where blood vessel clots or ruptures
Neurotoxic effect kills by apoptosis
O2 deprived cells release too much glutamate and leave Ca channels open too long

286

3 brain regions from bottom to top

Brain stem
Cerebellum
Forebrain

287

2 parts of forebrain

Diencephalon--> hypothalamus and thalamus
Cerebrum--> basal nuclei and cerebral cortex

288

Brain stem parts from highest to lowest

Midbrain
Pons
Medulla

289

Brain stem

Controls life sustaining processes and unconcious vegetative fucntions
Origin of peripheral cranial nerves
Sleep/wake cycle
Recpetion/integration of input from spinal cord

290

Cerebellum

Attached to rear brain stem
Maintains position in space, subconcious motor activity, muscle tone and learned motor activity

291

Thalamus

Primitive sensory processing, emotional and behavioral patterns

292

Cerebrum

outer cerebral cortex, inner basal nuclei
Sophisticated neural functions, voluntary movement, sensory perception, conciousness

293

Basal nuclei

Inhibition of muscle tone, slow coordination, suppression of uselss patterns

294

corpus collosum

band of neuronal axons coonect brain hemispheres
information superhighway

295

Crebral cortex

grey matetr covering core of white matter with basal nuclei deep inside
6 layers in vertical columns with distinct patterns of input/output

296

Grey matter

Densely packed cell bodies, dendrites and glial cells where neural input is integrated

297

Stellate cells

Rich in cortex region for perception and processing sensory input to cortex
layer 4

298

pyramidal cells

Areas controlling output to skeletal muscles, extend down spinal cord on efferent motor neurons
layer 5

299

4 lobes

occipital-- visual input processing
temporal-- sound
parietal-- recieve/process sensory input
frontl lobe-- voluntary motor activity, speaking, thought elaboration

300

Somesthetic sensations

body surface sensations projected to somatosensory cortex in parietal lobe
Each region of cortex processes info for different region of body

301

Proprioception

Awareness of body position
parietal lobe

302

Primary motor cortex

Back of frontal lobe near somatosensory cortex
Voluntary control of skeletal muscle movement on opposite side of body

303

Readiness potential

Motor cortex doesnt initiate voluntary movement, it activates pattern of neuronal discharge

304

Motor program

supplementary motor area, premotor cortex and posterior parietal cortex command the primary motor cortex
- cerebellum sends input about planning/timing
4 together coordinate voluntary movement

305

Supplementary motor area

inner surface ahead of motor cortex plys prepatory role in complex movement sequences

306

premotor cortex

lateral surface head of motor cortex
Orients trunk muscles towards target
Guided by posterior parietal cortex to know where body is

307

Posterior parietal cortex

Back f somatosensory cortex
CLosely connected with premotor cortex to deliver meaningful movement inclusing sensory info

308

Somatotopic map

Distribution unique to each person based on use dependant competition for cortical space

309

Brain plasticity

Ability to fucntionally remodel in repsonse to demand
Alter dendritic shape to take on other fucntions after injury

310

Language

areas only in left hemishere
requires integration of expression and comprehension

311

Brocas area

governs speaking ability, controls mouth muscles
in frontal lobe

312

Wernickes area

Left cortex and junction between parietl, occipital and temporal lobes
Comprehension of written and spoken messages
Formulate coherent patterns transfered by bundle fibres to brocas area to be articulated
Gets input from occipital lobe visual cortex, auditory in temporal lobe

313

Aphasia

Damage to specific cortical regions like fom a stroke

314

Speech impediment

Defect in mechanical aspect

315

Dyslexia

Innapropriate interpreattion of words from bad connection between visul and language areas of cortex

316

3 association areas in higher functions

Prefrontal association cortex
Parietal-temporal-occipital association
Limbic association cortex

317

Silent areas

Stimulation in association areas doesnt make visible response. Associations made by bundle fibres in white matter

318

Prefrontal association cortex

Front of frontal lobe for brainstorming
Planning voluntary activity, decision making
Site of working memory
Deficits chnage sociality--> lobotomy

319

Parietal- Temporal-Occipital Association cortex

integrates somatic, auditory and visual sensations to get the full picture

320

Limbic association cortex

Joins each temporal lobe at the bottom
Motivation, memory and emotion

321

Left hemisphere

Language, motor control
Excels in logic, analystics and verbal tasks
Thinkers

322

Right hemisphere

Non-language skills like spatial perception, music, art

323

Schematic linking of regions

Sensory input
Primary sensory areas
higher sensory areas
association areas
higher motor areas
primary motor cortex
motor output

324

Electroencephalograms

Detect current flow form activity in cerebral cortex
Brain waves are collective of post synaptic potential activity -- EPSP

325

Epilepsy

Alot of neurons fire APs showing spasma nd weird behavior
Too little inhibition or too much glutamate activity

326

Subcortical regions

Interact with cortex in performing functions
Basla nuclei in cerebrum
thalamus/hypothalmus in diencephalon

327

Basal nuclei

Inhibit muscle ton through excitatory/inhibitroy input to muscle
Monitor posture
Dont directly effect efferent neurons, do modify ongoing activity

328

Thalamus

Formswall of 3rd ventricle
Relay station and preliminary pricessing of sensory input before cortex--> screens out insignificant stuff, directs important stuff
Crude awarenss but no info about location or intensity

329

Hypothalamus

Integratin between autonomic NS and endocrine
control body temp, thirt, urine, food, anterior pituitary hormone secretion, posterior pituitary production
Directly regulates internal environment

330

Limbic system

Ring of forebrain structures around brain stem
Cerebral cortex lobes, basal nuclei, thalmus and hypothalamus
used for emotions, basic survival, motivation and learning

331

Amygdala

Temporal lobe-- processes inputs for fear
Produces instrinctive response where prefrontal cortex can guide behavior

332

LS behavior

Cortex connects LS to outer world to bring appropriate behavior
Suppress behavior based on judgement
Reward and punishment centres

333

Motivation

Norepinephrine and dopamine provide self stimulation
depression works on NTs in limbic system

334

Memory trace

Neural change responsible for retention in hippocampus, limbic cystem, cerebellum and prefrontal cortex

335

Consolidation

Transfering short term memories into long term

336

Hippocampus

Elongated medial portion of temporal lobe crucial for consolidation
involved in declaritive memories

337

Cerebellum memory

procedural memories which include motor skills

338

Short term memory

Habituation and sensitization modify protein channles in presynaptic terminals of afferent neurons

339

Habituated post synapse

Ignore stimulus
Closing Ca channels reduces NT release, potential reduced, doesnt cause behaviorsal repsonse

340

Sensitization in post synapse

Ca anetry enhanced, larger post synapse potential and greater response

341

Long term potentiation

prolonged increase in strength of existing synapses following repeated stimulation. Simulataneous activation of pre and post causes long lasting modifications
- prevalent in hippocampus

342

increase post synapse receptiveness in LTP

glutamate binds to NMDA or AMPS

343

NMDA receptors

non-selective cation channels for Ca and Na entry
- allows Ca 2nd messenger pthway to effect AMPa receptors in post synapse

344

AMPA receptors

Generate EPSP in response to glutamate
Creates greater EPSP response, heightened glutamate sensitivity maintains LTP

345

Increased Nt release in presynapse

Ca messenger causes release of retrograde factor from post synapse to enhance glutamate release in pre synpase
Positive feedback enhances signalling
uses NO as messenger

346

Long term memory

Requires gene activation to make new synaptic connections and permanent brain changes
Greater dendritic surface area

347

CREB

Regulatory protein turns on genes for LTM
CREB2 is repressor gene to inhibit contraining factors activated by CAMP

348

immediate early genes

regulated by CREB, role in consolidation
Governs protein synthesis that encodes LTM

349

3 parts of cerebellum

Vestibulocerebellum
SPinocerebellum
Cerebrocerebellum

350

Vestibulocerebellum

Maintain balance and control eye movement

351

SPinocerebellum

Enhance muscle tone, coordination, voluntary movement
Time muscle contractions at various joints
Corrects deviations from plan

352

Cerebrocerebellum

Plan and initiate voluntary activity, provide input to cortical motor areas
store procedural memories

353

Intention tremor

Cerebellum injury causes to and fro movement to target

354

Brain stem

pons, medulla oblongatea, midbrain--> continuous with spinal cord
fibres synapse with brainstem for processing

355

5 brainstem functions

12 pairs of cranial nerves arise from brainstem except vagus
Centres: neuronal clusters control basic functions
Regulate muscle reflexes in equilibrium and posture
Reticular formation
Centres governing sleep

356

Reticular formation

Interconnected neurons run through brain into thalamus
- Recieve and integrates sensory info

357

Reticular Activating system

Ascending fibres arouse cerebral cortex to control alertness, and direct attention
- Activated by decending fibres from cortex

358

States of conciousness

Maximum alertness
Wakefulness
SLeep
Coma

359

Slow wave sleep

4 stages showing progressivley lowerEEG waves of higher amplitude
light stage 1- deep stage 4

360

Paradoxical REM sleep

10-15 min episode at the end of each slow wave cycle where EEG patterns are the same as being awake
20% of sleep--> more in babies, less in old people

361

3 systems in sleep/wake cycle

Arousal system-- RAS
slow wave sleep centre-- hypothalamus
REM sleep centre-- brainstem

362

Arousal neurons

IPSPs must turn them off, easier to stay awake when sleep than to fall asleep while wide awake

363

Sleep reasons

Adensoine concentration grows while being awake and inhibits arousal centre

364

Narcolepsy

Sleep attacks caused by dysfunction in excitatory hypocretin

365

Spinal cord size

45 cm long, 2cm wide, extends to L1/2

366

Spinal nerves

through pedicle/lamina of each vertebrae
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

367

Caudal equina

Bundle of elongated nerve roots in lower vertebral canal

368

spinalcord ascending tract

transmit brain signals from afferent output

369

Descending tracts in sc

relay brain mesages to efferent neurons
named for origin and termination

370

spinal cord grey matter

Ventral horn: cell bodies of skeletal muscles
Doral horn: cell bodies of interneurons where afferent terminate
Lateral horn: autonomic nerve fibre origin

371

Spinal nerve dorsal root

Afferent fibres carry incoming signals from recptord

372

DOrsal root ganglion

CLuster of afferent neuron cell bodies

373

Ventral root

Cell bodies for efferent neurons
Roots join to form spinal nerve

374

Nerve

Bundle of peripheral axons enclosed by connective tissue ad following same path

375

Dermatome

Specific region of body surface supplies by one of 31 spinal nerves
causes refereed pain

376

Basic reflexes

SPinal cord integrates reflex activity between afferent and efferent input without using brain

377

Reflex arc 5 components

Receptor, afferent pathway, integrating centre, efferent pathway, effector

378

2 types of spinal reflexes

Integrated by spinal cord
Withdrawl
Stretch

379

Withdrawlreflex

Receptor stimulus
Ap on afferent neuron goes to spinal cord
Interneuorns supply efferent neurons
bicep contracts
afferent neurons inhibit interneurons supplying tricep

380

Reciprocal innervation

Reflex inhibits antagonizing muscles while stimulating nerve supply to another

381

modifying sonal reflex

CNS can send IPSP to maintain concious control

382

Stretch reflex

Afferent neuron in strecth detecting receptor in skeletal muscle terminates on efferent neuron supplying same skeletal muscle
causes contraction to counteract stretch

383

monosynaptic reflex

only synapse in reflex arc between afferent and effernt neurons
no interneurons

384

Crosses extensor reflex

withdraw reflex in injured leg activates other side of side of spinal cord to prepare other leg to bare weight

385

Somesthetic sensation

skin

386

Proprioception sensation

muscle spindles sense changes in length, synapses onto motor neuron to make it contract sufficently
- crouching before jump increases spindle firing rate

387

Transduction

Receptors turn stimuli into electric signals to be transmitted to CNS

388

Adequate stimulus

Receptor respond smore readily ro one type of stimulus
Osmorecpetors, chemo, nociceptors

389

Sensory input from RAS

goes to brainstem for central processing and bringing perception

390

Receptor is either

Specialized ending of afferent neuron
Seperate cell closely associated with peripheral ending

391

Receptor stimulation

Alters P by opening non selective ion channels
Inward Na brings receptor potnetial
Strong stimulus brings greater P chnage

392

Receptor potential

Local depolarizing change in receptor
No refractory period, no summation, very high threshold

393

Generator potential

AP in afferent neuron next to recptor
Triggers voltage gated Na channels to open
Bring both membranes to threhold

394

Ap initition site in afferent pathway

different because it is far from cell body

395

Adaptation

Receptors diminish extent of depolarization despite strong stimuli, frequency of AP decreased

396

Tonic receptors

Do not adapt or adapt slowly
Stretch receptors

397

Phasic receptors

Rapidly adapt and no longer eact to stimulus

398

Off response

Slight depolarization when constant stimulus removed

399

Pacinian corpuscle

Rapidly adapting skin receptor to pressure ad vibration
layers of connective tissue slip to expose neuron so it doesnt respond to continuous pressure
- electrochemical and mechanical adaptation

400

Difference between adaptation and habituation

Adaptation is in PNS receptors
Habituation is changing synaptic effectiveness

401

Somatosensory pathway

Convey concious somatic sensation by chains of neurons called labelled lines, help CNS decode info

402

First order sensory neuron

Afferent neuron with receptor
Second order sensory neruron in spinal cord or medulla
synapses with 3rd order in thalamus

403

Phantom pain

activation of sensory pathway causes percieved pain

404

Receptive field

Each somatosensory neuron responds to stimulus infor in one region of skim
Smaller field= greater acuity

405

Lateral inhiition

Strongly activated single pathway inhibits less excited fringe pathways fro localization

406

Pain

Nociception from external and internal events, accompanied by behavior and emotion

407

3 nociceptor categories

mehcnaical
thermal
polyoidal (respond to all damaging stimuli)

408

Prostaglandins

enahnce recpetor response to noxious stimuli, lower threshold fro activation
Aspirin inhibits prostaglandins

409

Afferent pain fibres

A delta: mechanical, thermal, small myelinated
C fibres: small, unmyelinated for polymoidal signal of slow pain causeing dull pain after injury

410

Bradykinin

Activated by local enzymes from damaged tissue, provoke polymodal receptors andadd to inflammation

411

Capsaican

Activates peripheral receptors of afferent C fibres

412

Subsatnce P

activates acsending pathways to transmit pain signals to higher levels in cortex, thalamus and RAS to enhance awareness of pain

413

Glutamate in pain

Binds to AMPA and NMDA to exaggerate sensitivity

414

Analgesic

Suppressed transmision of pain by activating PQ grey matter and RF to block release of substance P

415

3 layers of eye

Sclera: white outer part
Cornea: transparent outer part
Choroid: pigmented midle with blood vessels
Retina: innermost with outer pigment and inner nervous tissue

416

2 cavities seperated by lens

Vitreous humour: posterior between lens and retina, jelly maintains shape
Aqueous humour: anterior between cornea and lens, filled with water to carry nutrients to cornea

417

Glaucoma

Aqueous humour isnt drained and builds up in anterior cavity

418

Iris

pigmented smooth muscle in aqueous humour

419

circular muscle

contracts tomake pupil smaller, controlled by parasympathetic NS

420

radial dilator muscle

shortens so pupil gets bigger, controlled by sympathetic NS

421

Wavelength

Distance between 2 peaks, blue is shorter and red is longer

422

Refraction

Light strikes surface at angle other than perpindicular, cornea and lens most important to make focal point

423

Accomodation

Ability to adjust strenght of lens depends on ciliary muscle

424

Ciliary muscle

Circular ring of smooth muscle attached to lens by suspensory ligaments

425

lens near vision

Ciliary relaxed, ligaments taught, lens is flat

426

lens far vision

ciliary contracts, ligaments slack, lens is sphere

427

presbyopia

old age related reduction in accomodation

428

Cataract

elastic fibres in lens become opaque

429

Myopia

near sighted, eyeball too long, lens too strong
far light source focused in front of retina so concave lens needed

430

Hyperopia

farsighted, eyeball too short, weak lens
- near objects focused behind retina

431

Emmetropia

normal eyes, light source focused on far objects without accomodation, strengthen lens to focus on near objects

432

3 layers of backwards retinal cells

Outer is rods and cones facing choroid
Middle bipolar cells
Inner ganglion cells join optic nerve

433

Opti disc

Point where optic nerve, and blood vessels leave retina--> causes a blindspot without rods and cones

434

Fovea

Small depression in centre of retna, no ganglion oor bipolar cells so light hits cones--> best vision point

435

macula lutea

area surrounding fovea has alot of cones and good acuity but with overlying bipola andganglion

436

Macular degeernation

loss of photoreceptors in lutea by aging causes donut vision

437

Cones

detect colour and work well in bright light

438

Rods

More sensitive, less colour, better in low light

439

3 parts of photoreceptor

outer- faces choroid detects light, membranous discs with photpigments
inner: metabolic machinery
Synaptic terminal: Closest to eye interior, faces bipolar cells and transmit signals

440

Ospin

protein in disc membrane

441

retinene

Derivative of vitamin A, bound to interior of ospin molecule

442

4 photpigments

1 in rods, 3 in cones absorb diffeent wavelengths
red,green and blue

443

Phototransduction

Photorecetors hyperpolarize to send signals

444

Photoreceptors in dark

CGMP binds to Na channels to keep them open in dark
- only close when light stimulates
Inwards Na leak depolarizes photoreceptors
Keeps voltage gated Ca channels open to release NT in the dark

445

Photoreceptors in light

photpigment activation decreases cGMP
retinene changes shape when exposed to light
Transducin degrades cGMP
NA gates close
Hyperpolarization
Ca gates close and dont release NT
Photoreceptors excited by lack of stimulus

446

Bipolar cells

Synapse with photoreceptors and terminate on ganglion cells
NT released on receptors inhibits BP cells
inhibits optic nerve transmission

447

Cone output

Private wire to ganglion cell to a big stimulus is needed for threshold--> very small receptive field brings acuity at expense of sensitivity

448

Rod output

Many join on a ganglion cell so less AP needed for thresholf

449

Dark adaptation

Pigments break down in sunlight, decrease receptor sensititivity , regenertaed only in cones in the dark

450

Light adaptation

Pigment rapidly broken down, rods burn out

451

Colour vision

Dependant on ratio of stimulation in redblue green cones

452

Eye wiring

left-- inner half of left retina, outer half of right

453

optic chiasm

Info is seperated where optic nerves meet under hypothalamus

454

optic tract

reorganized fibre bundles leaving chiasm carry medial half of one retina an lateral half of the other

455

optic radiations

fibre bundles carry seperated info about vision to different zones in cortex

456

diploplia

Different views from eyes are seen at same time when binocular view isnt intgrated

457

external ear

pinna
externalauditory meatus
tympanic membrane

458

inner ear parts

cochlea, vestibular apparatus

459

pitch/tone

frequency of fibrations
higher F= higher pitch

460

Timbre/quality

Additional frequencies over original sound
- allows us to distinguish sound sources

461

pinna

skin covered cartilage channels waves in, aids in localization

462

Ear canal

produces cerumen and guided by fine hairs

463

Tympanic membrane

stretched across entrance to middle hear, bows in time with wave frequency
attached to malleus

464

Eustachian tube

connects middle ear to pharynx, equalizes atmospheric pressure
opned by yaning

465

3 middle ear ossicles

malleus, incus, stapes
vibrate with ear drum

466

Oval window

Entrance to cochlea attached to stapes

467

Coclea fluid filled compartments

Scala media- middle through centre
scala vestibuli: upper, follows inner spiral
Scala tympani: lower followsouter contour

468

Endolymph

fluid in cochlear duct

469

perilymph

fluid in scala vestibuli and tympani

470

helicotrema

region beyond cochlear duct where fluid in upper an lower compartments is continuous

471

round window

seals tympani from middle ear

472

vestibular membrane

ceiling of cochlear duct between vestibuli

473

Basilar membrane

floor of cochlear duct between tympani

474

Organ of corti

inside basilar membrane, hearing organ

475

Hair cells

sound recetors on organ of corti
1 inner layer, 3 outer rows

476

Stereocilia

Actin stiffened microvili on each hair cell
mechanically deformed in fluid to transmit nerve impulses

477

Tectorial membranse

contain microvili, project over organ of corti

478

inner hair cells

sense movement back and forth on basilar/tectorial membranse
Opens mechanically gated ion channels, alternating depolarization and hyperpolarization at same frequncy

479

cochlear nerve

inner hair cells communicate with afferent nerve terminals via chemical synapse
depolarized when bailar membrane deflected upwards
mechanical deformation altrnatly opena nd closes channels

480

outer hair cells

cahnge in response to membrane potential, amplify motion ofbasilar membrane through electromotility

481

pitch discrimination

narrow wnd at oval windo vibrates with high frequency
wide end at helicotrem vibrates maximally at low frequncy
wave dies out at region of maximal displacement

482

timbre discrimination

varying frequencies cause many points of BM to vibrate but less intensely

483

primary auditory cortex

linked to region on basilar membrane, only activated by particular tone

484

conductive deafness

sound waves not adequately conducted

485

sensorineural deafness

sound waves transmitted but not transated into nerve signals

486

neural presbycusis

degernative age related loss of hair cells, lose high frequncy

487

Vestibular appartus

for equilibrium
semicircular canalas and orolith

488

semicircular canals

detetc rotational movement
hair cells located in ampulla
embedded in gel layer called capula which sways in direction of movement

489

Acceleration rotation of head

Endolymph moves in opposite direction until cupula catches up
stereocilia deflected in movemeent
pulls on mechanically gated channels in hair cell

490

kinocilium

hir cell depolarizes when sterocilia bent rowards kinocilium, hyperpolarized in oppositie direction

491

vestibular nerve

chemically mediated synapse with afferent structures and vestibule

492

Orolith

info on head with gravity, linear mption rate
utricle and saccule

493

utricle and saccule

sacs in bony chamber between semicircular canalas and cochlea

494

ololith

calcium carbonate gel with hairs in it
cause changes in potential with movement

495

utricle

titlting bends hairs in direction of tilt with gravity
linear motion makes hais lag behind in heavy ololith

496

vestibular info into cerebellum

balance posture
control external eye movemet
perciev motion and orientation

497

menieres disease

fluid imbalnanc ein neer ear

498

Taste receptor cells

chemoreceptors in taste buds in oral caviy and throat
microvili increase chemicals

499

cortical gustatory area

region of parietal lobe next to somatosensory cortex that is not crossed
gets info from hypothalamus and limbic system

500

5 primary atstes

salty- NA entry depolarizes
Saour- Acid, H blocks K and depolarizes
Sweet- activates g protein, CAMP second messenger, blocks K and depolarizes
Bitter- diverse structures for wide detection
umami-- triggered by AA, glutamate

501

olactory receptors

mucosa in nasal cavity have recpetors, supporting cells an dbasal cells

502

supporting/ basal cells

supporting- secrete mucous
basal- precursor for olfactory receptors

503

smell detection

Odourant dissected into compartments, appropriate scent binds to receptor, G protein activates CAMp to open Na channels

504

glomeruli

neural junctions lining 2 olfactory bulbs with terminal mitral cells that carry info
- smell files

505

fibres leaving olfactory bulb go to

subcortical limbic system and primary olfactory cortex
Wrote through thalamus for concious perception

506

Odour discrimination

Scents based on patterns of glomeruli activation

507

Adaptability

new odour diminished rapidly after exposure due to odour eating enzymes

508

vomeronosal organ

Detects pharamones and trigger limbic system response

509

2 effector NTs

acetylcholine
norepinephrine

510

ANS nerve pathway

preganglionic fibre with body in CNS synapses with cell body in ganglion
postganglionic fibre innervates organ

511

sympattheitc NS

fibres origin in T/L spinal cord
short preganglion fibres synapse with cell bodies in sympathetic ganglion trunk
long post ganglion ends at effecror

512

Collateral gangliom

some pre fribres pass trunk and synapse halfway between CNs and effector

513

Parasympathetic NS

preganglion from C/S regions
Preganglion are longer becuase they end at terminal ganglia near effector organ
very short post ganglion end on organ

514

Cholinergic fibres

ACH released by all ANs pre ganglion
and also by parasymptathetic post ganglion

515

Adrenergic fibres

Sympathetic post ganglion rlease noradrenaline

516

Varicosities

Branches of ANs post ganglion release NT to organ rather than cells
electric activity spread through cardiac/smooth musclevia gap junctions

517

Tonic acitivity

para and sympathetic both partially active all the time

518

Sympathetic dominance

Fibres fire rate above tonic levelwidespread changes more common in sympathetic during fight or flight

519

parasympathetic dominance

Rest and digest
slow down activities enhanced by SNS

520

Dual autonomic innervation

Accelerator and brake system on organs makes changes more rapidly

521

3 things that are not dually innervated

Blood vessels only symp.
Sw glands only symp.
Salivary glands-- both systems do same thing

522

Adrenal medulla (inside cortex)

modified sympathetic ganglion with post ganglion
20% norepinehrine
80% epinephrine

523

Cholinergic receptors

2 ACH receptord for nicotine and muscarine

524

Nicotonic receptors

Found in all ANs postganglion
Respond to ACH, allow passage of N and K
depolarizes post ganglion

525

Muscarine receptors

On effector cell membranse
Bind with ACH from Para post ganglion
G proteins activate second messenger

526

Adrenergic receptors

A1,A2, B1, B2, B3 for epinephrine/norepinephrine
Receptors act through 2nd messenger to get into cytoplasm

527

Alpha adrenergic

affinity for norepinephrine
A1 uses Ca 2nd messenger, excitaory response
A2: blocks CAMP, inhibitory

528

Beta adrenergic

B1: camp second messenger, equal affinity for nor, epi, found in heart
B2- epinephrine, uses CAMP, inhibits respiration

529

Agonist

Binds to same receptoras NT to mimic same effect

530

Antagonist

Binds with receptor to block NT repsonse

531

4 CNS regions regulating ANs output

Spinal cord
Medulla
Hypothlamus
Prefrontal association cortex

532

Somatic NS

Cell body in ventral horn of spinal cord, terminals on muscle release ACH
only inhibited by CNS control

533

Converging presynaptic inputs on motor neurons

Motor cortex
basal nucli
cerebellum
brain stem
-- activity depend son balance of EPSP and IPSP

534

ALS

changes in neurofilaments that block axonal transport of materials causes accumulation of glutamate, mitochondrial dysfunction and messed proteins

535

Neuromuscular Junction

Efferent axon divides into terminal branches and lose mylein, form juncion with muscle fibres

Space too large for AP so ACH carrier mesage to fibre

536

Terminal button

Axon terminal enlarged with knob fitting into cleft in muscle fibre
stores ACH

537

Motor end plate

Portion of muscle under termnal button

538

Muscle innervation

Axon temrinal triggers Ca gated channel to open in terminal button, diffuses in
Release of ACH into cleft
Binds to proteins on motor end plate
open chemical channles in end plate

539

End plate potential

ACh triggers way more Na in than K out which depolarizes motor end plate like EPSP but bigger
local current depolarizes adjacent regions in both directions

540

why is EPP bigger than APSP

more NT released
Motor end plte has bigger SA with more receptor sites than subsynapse
More ion channels open

541

ACHE

enzyme in motor end plate swicthes off muscle for purposeful movement

542

black widow

explosive release of ACH making all cholinergic sites depolarize
respiratory failure

543

depolarization block

voltage gated na channels trapped in inactive state prohibiting new APs from forming

544

Botulism

Food poisoning blocks release of ACH from terminal button so muscles cant reposnd to impulses

545

Curare

block effect of released ACH at NMJ, antagonist binds to receptor on motor end plate

546

Organophosphates

modify NMj activity by inhibiting ACHE, preventing inactivation of ACH

547

Myasthenia gravis

Muscular weakness when body produces antibodies against ACH receptors so ACHE destrys it all

548

Nestogimine

Drug inhibits ACHE temporarily to prolong action of ACH

549

Teleological approach

dody functions in terms of meeting needs--> why

550

Mechanistic approach

Actions explained as cause and effect-- how

551

96% of body is

O
C
H
N

552

Hydrogen bond

attracton of positive H end of one molecule to the negative end of another

553

Mole

material contained in pure subsance has has a mass equal to atomic weight in grams
1 mol of H2O is a 18.02 g smape

554

Avogadros number

Number of particles in a mol 6.02 x 1023

555

Molarity

# of mols of solute in one litre of solution

556

Osmolarity

# of solute particles in 1 L

557

Colloid

mixture of DPPs that are no more tha 100x bigger than molecules in solution

558

Suspension

DPPS bigger than colloids, will settle due to gravity

559

5 carb functions

provide energy
Stored energy form
Dietary fibre
Supply C for syntheis of cell components
Form structural elements

560

glycogen

stored carb, branched netowrk of glucose

561

starch

less branched glucose network, stored carb of plants

562

cellulose

unbranched glucose chains, structural carb of plats

563

simple lipids

contain fatty acids and alcohol

564

fatty acid molecule

hydrocarbon chain with carboxyl group

565

amino acid

Amino group Carboxyl group and Rgroup

566

Peptide bond

amino group of one AA and carboxyl group of another

567

nucelotide

Nitrogenous base
sugar
phosphate group
chain between phosphate and sugar

568

ATP

adenine with 3 phosphates

569

adenosine monophoshpahet

CAMP intracellular messenger effecting enzymes

570

embryonic stem cells

from blastocysts
derive embryonic tissues

571

adult stem cells

act with progenitor cells as repair system

572

Blastocyst

inner cell mass-- forms embryo
trophoblast-- placenta
inner cell cavity

573

8 basic cell fucntions

Obtain nutrients and O2
Chemical reactions to make energy
Eliminate CO2 and wastes
syntheisze proteins
control material exchange through membrane
move materials or entrie cell
reproduce
sensitive and responsive to environemnt

574

ECF

mad eof plasma and interstitial fluid

575

7 homeostatic regulations

constant concentration of nutrients
O2/CO2 concentration
Concentration of wastes
PH
Concentration of water/salt/electrolytes
Volume and pressure
Temperature

576

Extrinsic homeostatic controls

Iniated outside organ through nervous and endocrine systems

577

Negatuve feedback

Deviation
sensor
Integrator
Effector
Response

578

6 organelles in cytoplasm

ER
GC
lysosome
peroxisome
mitochondria
vaults

579

Rough ER

dotted with ribosomes that release proteins into lumen where they are folded

580

Smooth Er

interconnected tubules package and send out productsin vesicles