late night finds AUG 8th Flashcards

1
Q

glial cells

A

cells that support the neurons
- structurally and support - astrocytes (BBB), microglia (phagocytic), oligodendrocytes (produce mylein), ependymal ( produce spinal fluid)

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2
Q

potassium equilibrium in and out of the cell?

A

140mM inside and 4mM outside

so due to concentration gradient K leaks out, but then bc inside is negative, K+ is also pulled in —> this finds a equilibrium so overall no net movement

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3
Q

equilibrium potential of potassium

A

-90mV (negative bc + ion is leaving)

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4
Q

equilibrium potential of sodium

A

12mM inside and 145mM outside so concentration leaks Na into the cell (positive ion inside) —> 60mV

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5
Q

net resting potencial is

A

70mV`

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6
Q

two types of summation

A

temporal (one neuron) and spatial (many neurons)

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7
Q

temporal summation

A

several from one neuron over time

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8
Q

spatial summation

A

several impulses from many different neurons

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9
Q

after threshold is met what ion flows in

A

Na+ influx

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10
Q

after action potencial isreached what repolarizes it

A

K+ flows out

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11
Q

what casues sodium to go into the cell if threshold is reached

A

strong electrochemcal gradient - voltage gated channels open

  • electrical - inside is more negative
  • chemical - flows down concentration gradient ( there is less sodium inside the cell)
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12
Q

impulse propagation

A

when an action potencial travels down anaxon

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13
Q

if an axon is wider what is the resulting impulse propagation speed?

A

it is faster!! bc greater cross-sectional area means less resitence

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14
Q

does length or area affect impulse propagation speed more sigificantly?

A

area! bigger area= faster impulse

longer length= higher resistence= slower conduction

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15
Q

why does myelien speed up transduction

A

bc it insulates the axons so well to prevent dissapation of electric energy- so well that the membrane is only permeable at nodes de ravier- thus signal hops = saltatory conduction

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16
Q

incereased intensity of stimuli results in ?

A

increase f of firing

17
Q

whats the dif between electrical and chemical transmission

A

electrical is down a neuron in AP and chemical is across a synapse - with NT

18
Q

how at NT released

A

when AP reaches, voltage-gated Ca open and let in Ca- triggers release of vesicles- eocytosis

19
Q

spinal cord is protected with

A

vertebral column

20
Q

spinal crd divided into ( from top to bottom)

A

cervical, thoracic, lumbar, sacral

21
Q

dorsal root ganglia

A

contains the cell bodies of sensory neurons - in the spinal cord - so central NS
- pain, mechanical stim, first order neurons, reflex arch

  • The term ‘ganglion’ means a collection of neuronal cell bodies present in the peripheral nervous system. A ganglion consists of cell bodies of neurons present in the peripheral parts of the body. Hence, a ganglion is a part of the peripheral nervous system.
  • One of the several types of ganglia present in the peripheral nervous system is dorsal root ganglion.
22
Q

somatic NS

A

joints, skin and muscle- sensory and motor neurons/opposite of autonomic

23
Q

the main difference between to somatic and the autonomic NS

A

is that the autonomic NS contains two neurons and a synapse in the peripheral part

  • first is the preganglionic neuron (soma is in CNS)
  • second is postganglionic

but inthe somatic, motor neurons go directly from spinal cord to muscle without synapsing

24
Q

which system has 2 neurons in PNS

A

the autonomic NS

25
Q

two types of reflex arch

A

monosynaptic and polysynaptic

26
Q

monosynaptic reflex arch

A

there is a single synapse between the sensory neuron the perceives it and the motor that pulls back - so no interneuron (knee-jerk)

27
Q

polysynaptic reflex arch

A

there is atleast one interneuron (withdrawal reflex - stepping on a nail)

28
Q

penetrance vs expressivity

A

penetrance = proportion of individuals in a pop carrying the allele that actually express the phenotype

expressivity= the differnt manifestations of the same genotype acrooss a population
- the varying phenotypes despite identical genetypes

29
Q

example of penetrance

A

hungtintons disease

  • ppl with 40 repeat cycles will have full penetrance - 100% of ppl with this genotype will have symptoms
  • individuals with less sequences show high penetrance
30
Q

expressivity constant

A

then all ppl with saem genotype = same phenotype

31
Q

expressivity variable

A

same genotype but different expressivity (variability in individual) - example in one dominant allele- but multiple different symptoms

32
Q

genetic leakage

A

a flow of genes between species - mate to produce hybrid offspring such as a mule

  • cant reproduce bc odd number of chromosomes
33
Q

a mule is an example of

A

genetic leakage

34
Q

genetic drift

A

change of composition of the gene pool due to change(no enviromental explanation it is due to chance!)

  • is a change in the frequency of an allele within a population over time. This change in the frequency of the allele or gene variation must occur randomly in order for genetic drift to occur. There are no environmental influences that cause genetic drift to occur. Examples of genetic drift are more evident in smaller populations of organisms.
  • The American Bison was hunted to near extinction and even today as the population has recovered, the result is a population of bison with little genetic variation
35
Q

founder effect

A

more extreme case of genetic drift, where a small partof a population finds itelf in reproductive isolation as a result of natural barriers or other bottlenecks that drastically and suddenly reduce the size of pop available for breeding- results in inbreeeding

36
Q

inbreeding results in

A

homozygosity- increases the prevalence of homozygous for dom and rec mutations/genotypes

37
Q

examples of genetic drift

A

The American Bison was hunted to near extinction and even today as the population has recovered, the result is a population of bison with little genetic variation

A certain type of plant can produce blue or yellow flowers. During a fire, many yellow flowers are destroyed and now since blue is the dominant allele, the plant reproduces plants that only produce blue flowers.

-A population of rabbits can have brown fur and white fur with brown fur being the dominant allele. By random chance, the offspring may all be brown and this could reduce or eliminate the allele for white fur.

A mother with blue eyes and a father with brown eyes can have children with brown or blue eyes. If brown is the dominant allele, even though there is a 50% chance of having blue eyes, they might have all children with brown eyes by chance.

A bird may have an allele for two different beak sizes. Depending on which alleles show up in the offspring, genetic drift could cause one of the beak sizes to disappear from the population thus reducing the genetic variation of the birds gene pool