wk 1-3 structure, function, evolution, genetics, neurotransmission Flashcards
(139 cards)
1
Q
cell body
A
has the nucleus, mitochondria, ribosomes, golgi apparatus and endoplasmic reticulum
2
Q
What type of neuron has many dendrites and a single axon?
A
Multipolar neuron
Most common type of neuron.
3
Q
Describe a bipolar neuron.
A
Single dendrite at one end and single axon at the other
Common in sensory systems, like the visual system.
4
Q
What is a unipolar neuron?
A
Single extension, usually an axon that branches in two directions
Transmits touch information from the body to the spinal cord.
5
Q
What do sensory neurons do?
A
Carry messages to the periphery to the spinal cord and brain
Diverse shape and function.
6
Q
What is the function of motor neurons?
A
Innervate muscles and movement, innervate organs and glands
Sometimes motoneurons can have very long axons.
7
Q
What are interneurons responsible for?
A
Receive information from other neurons, process it, and pass it onto other neurons
Most of your networks are interneurons.
8
Q
What are dendrites?
A
Cellular extensions that serve as the input zone, receiving information from other neurons. They may be elaborately branched.
Dendrites play a crucial role in the communication between neurons.
9
Q
Where does the axon arise from?
A
The axon arises from the axon hillock, which is the integration zone.
The axon hillock is critical for determining whether a neuron will fire an action potential.
10
Q
What is the function of axon collaterals?
A
Allow one cell to influence a number of other cells.
Axon collaterals enable neurons to communicate with multiple targets.
11
Q
What is axonal transport?
A
The process that moves materials within the axon.
Axonal transport is essential for maintaining neuron function and health.
12
Q
What are axon terminals?
A
Specialized swellings at the end of the axon (synaptic boutons) that transmit the neuron’s activity to other cells at the synapse.
Axon terminals are crucial for neurotransmitter release and communication between neurons.
13
Q
Axon varicosities
A
small bead-like swellings along the length of the axon, transmit signals to neighbouring cells
14
Q
what cells produce myelin and wrap it around the axon
A
oligodendrocytes (cns) and schwann cells (peripheral)
15
Q
benefits of myelination
A
1.increases speed the signal can travel along axons (electrical pulses can jump between nodes of ranvier)
2.reduces energy consumption
3.protects and supports axons (prevents degradation and sheilds axon)
16
Q
nodes of ranvier
A
small gaps in myelin sheath that occur at regular intervals
17
Q
does myelination stop at birth
A
no continues through adolescence
18
Q
what is MS caused by
A
demyelination
19
Q
neuronal membrane
A
neurons are covered with a cell membrane which is a fatty barrier that doesnt dissolve in the watery environment of our bodies
-membrane is semi-permeable
20
Q
ions
A
An atom or molecule that has acquired an electrical charge by gaining or losing one electron
21
Q
Anions-
A
a negatively charged ion, such as protein or a chloride ion
22
Q
Cation-
A
a positively charged ion, such as potassium (K)or calcium (Ca2+) or sodium (NA+)
23
Q
what does intracellular mean and what is the fluid called
A
intracellular means inside the cell. Intracellular fluid is called the cytoplasm
24
Q
what does extracellular mean and what does fluid do
A
outside the cell, fluid fills the gaps between cells
25
resting membrane potential
when a neuron is resting, the charge between inside the cell and outside is different, more negative inside than outside
26
how is resting neuron potential maintained
sodium potassium pump, membrane permeability to ions, equilibrium potential
27
sodium potassium pump
pushes 3 Na+ (sodium) out and 2 K+ (Potassium) in, which maintains the creates higher concentration of Sodium outside the cell and a higher concentration of potassium inside the cell. This requires ATP
28
membrane permibility to ions
the membrane is more permeable to potassium than sodium, potassium can enter through channels
29
equilibrium potential
potassium wants to be balanced. When enough potassium ions leave the cell, the force that is pulling potassium inside is balanced by the gradient pushing potassium outwards. Ka+ equilibrium potential = -60mV
30
whats depolarization
when a cell becomes less negative (more positive)
31
what does polarized mean
when the neuron is in resting membrane potential (-70mV)
32
what happens in depolarization, how does action potential begin
if there a stimulus, small pores open on the neuronal membrane, allowing NA+ ions to rush in. the cell becomes positive enough (reaches threshold of excitation) then it becomes active and action potential begins
33
epsp cell
excitatory postsynaptic potential
is the cell that undergoes depolarization
34
IPSP cell
inhibitory post synaptic potential. Hyperpolarization, makes it less likely to fire (makes cell more negative)
35
explain all or nothing action potential
An incoming signal from another neuron is either sufficient enough or insufficient to reach the threshold of excitation. There is no inbetween.
36
what is pattern and timing for action potential
pattern- integration of excitation and inhibition
timing- how far apart are the incoming signals arriving
37
what neurons can fire many times per second
fast spiking cortical neurons (453 Hz per second)
38
acetylcholine- where, what does it do, what are the receptors for it
septal nuclei of the basal forebrain, responsible for arousal and cognition, the receptors are nicotine and muscarinic
39
nicotine receptor
same receptor for acetylcholine, ionotropic (allows ions to move) and excitatory (depolarises and causes rapidly triggers action)
40
muscarinic receptor
type of receptor for acetylcholine, metabotropic (slower, longer-lasting effects) can be both inhibitory and excitatory. They all decrease cell activity by hyperpolarization.
41
dopamine- where, what are the pathways
ventral tegmental area, mesostriatal pathway and Mesolimbocortical pathway
42
norepinephrine, where and what does it do
innervates the entire brain and spinal cord binds to metabotropic receptors, important for arousal, mood, stress
Found in locus coeruleus
43
hallucogen and dissociate drugs
alter sensory perception, LSD, ketamine
44
What is serotonin associated with?
Sleep, mood, anxiety
## Footnote
Serotonin plays a crucial role in regulating various physiological functions.
45
How many types of serotonin receptors have been found?
19 types
## Footnote
All but 1 of these receptors are metabotropic.
46
Where are serotonin receptors primarily found?
Inraphe nuclei of the brainstem
## Footnote
These receptors are crucial for mood modulation and appetite suppression.
47
What effect does LSD have in relation to serotonin?
LSD has a similar effect
## Footnote
LSD is known to mimic the effects of serotonin, influencing mood and perception.
48
GABA- functions
Reduces neuronal excitability, Promotes relaxation & sleep, Reduces anxiety & stress, is amino acid transmitter
49
what do stimulants do and examples
increase the activity of the nervous system, nicotine, caffeine, amphetamine
50
What is the primary role of glutamate? what happens if it's disrupted
excitatory neurotransmitter. Important for memories, schizophrenia can be a result of disrupted glutamate signalling
## Footnote
Glutamate is a key neurotransmitter involved in synaptic plasticity and memory formation.
51
analgesics
relieve pain, opiates
## Footnote
Altered glutamate signaling is implicated in the pathophysiology of schizophrenia.
52
What is excitotoxicity in relation to glutamate?
An excessive release of glutamate that overexcites and eventually kills neurons
## Footnote
Excitotoxicity can occur during events such as stroke or trauma.
53
What can provoke an excessive release of glutamate?
Stroke or trauma
## Footnote
These events can lead to excitotoxicity, damaging neurons.
54
antidepressants
relieve mood problems, ssri's and snri's
55
antipsychotic drugs
can help relieve symptoms of schizophrenia, chlorpromazine, heloperidol
56
anxiolytics
relieve symptoms of anxiety, benzodiazepines (has high potential for abuse)
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58
What is excitotoxicity?
Excessive release of glutamate that overexcites and eventually kills neurons, often strokes and trauma cause this
## Footnote
Often occurs in conditions like stroke or trauma.
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60
What is convergent evolution?
Similarities in behavioral structure among unrelated animals due to adaptations to similar environments
## Footnote
Examples include tuna and dolphin
61
What does homoplasy refer to?
Resemblance between features such as body shape due to convergent evolution
62
What is homology?
Similarities based on common ancestors
63
Define analogy in biological terms.
Refers to the idea of similar function despite different structures
64
Give an example of analogy.
A human hand and an elephant's trunk are analogous because they perform similar functions
65
What significant work did Mendel do in 1866?
Crossbreeding peas with different color flowers to study inheritance patterns
66
What did Mendel observe about flower color in peas?
Plants had the same color as either one flower (red or white), not a mixture
67
What important concept did Mendel discover regarding white flowers?
The white flower could skip a generation, indicating traits could be carried
68
What role do mutations play in evolution?
Mutations create variation that can be passed on
69
Who was Carolus Linnaeus?
A scientist known for classifying species and defining genus and species
70
What is a genus?
A group of species that resemble each other
71
Define species in biological classification.
A group of individuals that can interbreed and produce fertile offspring
72
order of taxonomic system
KINGDOM PHYLUM CLASS ORDER GENUS SPECIES
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what drives evolution
natural selection
74
What are some reasons to study certain animals?
Outstanding features, ethical considerations, comparison, understanding or treatment of disease
## Footnote
Studying animals can provide insights into sensory skills, ethical implications, and potential medical advancements.
75
What genetic mutation is found in narcoleptic dogs?
Mutation in the hypocretin receptor gene
## Footnote
Hypocretin is important for maintaining wakefulness and preventing direct transitions into REM sleep.
76
What are the main features shared by vertebrate nervous systems?
Develop from dorsal neural tube, bilateral symmetry, segmentation, hierarchical control, separate peripheral and central systems, localization of function
## Footnote
These features suggest a common ancestral origin for vertebrates.
77
How has the behavior of vertebrates changed in relation to brain evolution?
General tendency for brains to increase in size over the last 100 million years
## Footnote
Fossils and modern animals provide evidence for these evolutionary changes.
78
What is an endocast?
A cast of the brain made from a skull
## Footnote
Endocasts allow researchers to study the internal structure of the brain, including nuclei and circuitry.
79
What does the encephalisation quotient relate to?
Brain size and body size
## Footnote
A larger brain is generally correlated with a larger body size.
80
What does the evolution of brain size show?
Changes overall and in specific regions
## Footnote
The size of each brain structure is correlated with total brain size, and the rate of increase can differ between small and large brains.
81
At what stage is the development of the medulla complete?
At birth
## Footnote
In contrast, the development of the cortex continues throughout childhood.
82
What can subtle changes in gene expression lead to?
Profound effects on brain development
## Footnote
These changes can significantly influence brain size and function.
83
Genetic mutations
-errors sometimes occur during cell division leading to mutations
Most are benign, but sometimes they confer a genetic advantage or disadvantage
84
single nucleotide polymorphisms
Single nucleotide polymorphisms
-genetic code differs in only one location
-these are snp's
84
epigenetics
heritable changes in gene expression (whether a gene is "turned on" or "off") that occur without alterations to the DNA sequence itself, focusing on how environmental and lifestyle factors can influence how genes are expressed.
85
how many chromosomes in cells, gametes, zygotes
Most cells-23 pairs chromosomes x and y
Gametes-23 chromosomes
Zygote contains 23 chromosomes from the mother and 23 from the father (46 total same as other cells)
Zygote grows through cell division
86
genotype
Genotype- organism makeup, determined at conception
87
phenotype
observable characteristics, always changing
88
homozygous
-Homozygous- possessing two identitical alleles of a specific gene inherited from both parents
89
heterozygous
Heterozygous- refers to having two different allels of a gene inherited one from each parent
90
dominant allele
Dominant allele- phenotype produced regardless of whether its a pair is homo or hetero
91
recessive allele
phenotype produced only in homozygous pair
92
transcription
Transcription- copy of DNA is made into RNA
93
what do genes contain
Each gene contains instructions for making a protein
-a string of amino acids
-structural components of body tissue (eg, enzymes, some hormones)
94
Nucleotides (DNA is made up of these 4)
Adenine
Guanine
Thymine
Cytosine
95
Gene expression-
occurs when genetic instructions are converted into a feature of a living cell
96
sociability in reference to brain size (primate lifestyle)
Sociability
-suggests a larger cortex is needed to maintain social relationships between similar individuals
97
Diet in reference to why brain sizes vary (primate lifestyle)
More difficult food to get has correlation to brain size
Eg fruit harder to find over leaves
Monkey that eats more fruit has higher brain weight
98
Costs of a large brain
-long gestation period
-prolonged dependence on parents
-high metabolic cost (15% cardiac output, 20 oxygen consumption 25 total body glucose utilization)
-Complex genes are vulnerable to mutation
99
what are glia cells
surround neurons and hold them in place
-supply nutrients and oxygen
-synaptic transmission
-insulations
-Destroy pathogens and remove dead neurons
100
Groups of axons
Outside cns are called... and inside cns are called...
outside= nerve inside= tract
101
axon collaterals
Axon collaterals- branch off the axon to reach multiple targets
102
Types of glia cells
-oligodendrocyte
-nodes of Ranvier
-myelin
-astrocyte
-capillary
-microglia (cleans up cellular debris)
-ependymal cells
-cilia
-cerebral ventricle
-brain parenchyma
103
afferent v efferent
Afferent (ARRIVE) - is incoming, refers to sensory information coming into CNS
Efferent (EXIT) - outgoing, refers to information leaving the CNS
104
coronal and sagittal
-coronal- vertically (down to ground when standing up)
-sagittal- down middle of 2 hemispheres (looking from above)
105
what is the function of the CNS and what is under the central nervous system
mediates behaviour, brain and spinal cord
106
what is under the somatic nervous system and what is its function
transmit sensational, produces movement, craniel nerves and spinal nerves
107
autonomic nervous system
balances internal functions, sympathetic nervous system and parasympathetic nervous system
108
cranial nerves (somatic nervous system)
afferent sensory input to the brain from eyes, ears, nose and mouth
Efferent motor output to facial muscles, tongue and eyes
Both afferent and efferent functions like sensation and motor control in the face
109
spinal nerves (how many)
-31 pairs of nerves
-functionally equivalent to the cranial nerves
-sensory input travels by the dorsal root
-motor output via the ventral (stomach to ground) root
110
surface of the brain
-scalp
-skull
-Dura mater- meninges
-arachnoid membrane- meninges
-pia mater- meninges
111
whta are the ridges and valleys
-peaks- gyrus (gyri)
-troughs- sulcus (sulci)
112
what purpose do lateral ventricles have
shock absorbers, filled with fluid
113
white and grey matter
-grey matter (cell bodies of neurons)
-white matter (fat membranes of cells)
114
corpus collosum
-corpus collosum (axons that join the 2 hemispheres of brain)
115
explain spinal cord
Most body movements, usually following brain instructions, sometimes acting independently
-switching stations that receive input from a discreet part of the body and send commands out to the same area
-spinal nerves are part of the somatic nervous system
(sensory information from the skin, muscles and related structures, send motor instructions to control each muscles)
116
regions of spinal cord (clever teens learn science)
Cervical, thoracic, lumbar, sacral
117
what does Hind brain do and what does it contain
-breathing, balance and fine movements, reticular formation (sleep wake cycle)
-cerebellum
-pons and medulla (respiratory and cardiovascular)
118
Cerebellum
'little brain'
-input from sensory sources and other brain motor systems
-coordination
-motor and non motor learning
-voluntary movements
-has 3 parts
119
Midbrain
-tectum (roof) dorsally
-tegmentum (floor) ventrally
-tectum receives sensory information from eyes and ears
-Tegmentum contains several nuclei largely related to movement related functions
120
Diencephalon (function, hypothalamus, thalamus)
-integrates sensory and motor information on its way to the cortex
-thalamus (relay centre for sensory info projecting to the cortex
-hypothalamus (control the bodies production of hormones by interaction with the pituitary gland
HPA Axis- cortisol
121
Forebrain-largest region of the mammalian brain
thinking, memory, emotions, voluntary movements.
-cortex; associated with multiple function
-basal ganglia; voluntary movement
-limbic system; emotional states, memory
122
Basal ganglia
-motor control include 4 nuclei
-caudate nucleus, putamen and the Globus pallidus under the cerebral cortex
-substantia nigra
-important for control and coordination of movement patterns, not in activating the muscles to move
123
Limbic system (what it contains)-emotions as well as learning and memory
-amygdala (emotional regulation and perception of odor)
-hippocampus and forenix (learning)
-cingulate gyrus- attention
Olfactory bulb-sense of smell
124
hypothalamus (endocrine system)
control of hormone secretion
125
pineal (endocrine system)
reproductive maturation body rhythms
126
pituitary gland (endocrine system)
-pituitary gland; anterior and postierior releases hormones
127
anterior pituatary gland (endocrine system)
-Anterior- hormone secretion by throid, adrenal cortex, gonads;growth
128
posterior pituatary glnad (endocrine system)
water balance, salt balance
129
thyroid (endocrine system)
growth and development' metabolic rate
130
-Adrenal glands/cortex (endocrine system)
salt and carbs metabolism, inflammatory reactions
131
Adrenal medulla (inner core) (endocrine system)
emotional arousal
132
metabolism (endocrine system)
sugar metabolism
133
what happens in the gut (endocrine system)
digestion and appetite control
134
ovaries/testes (gonads) (endocrine system)
body development maintenance of reproductive organs in adults
135
-hyperthyroidsm
too much thyroid hormone in the body. Rapid heartbeat or palpitations
Weight loss despite normal or increased appetite
Nervousness, anxiety, irritability. Eg, graves disease
136
hypothyroidism
reduced hormone levels cause people to experience tiredness feeling cold, weight gain
137
adrenal glands
secret hormones involved in the stress response, such as cortisol, epinephrine (adrenaline) and norepinephrine (noradrenaline) chronic stress is associated with several illnesses including depression
138
pancreas
produces insulin
