Midterm Flashcards
1
Q
How can woodpeckers avoid concussion?
A
- Reduce the space between your brain and skull (Less sub-dural space)
- Have a brain that is longer from top-to-bottom (Larger surface area to absorb shock)
- Have a thicker, spongier skull (Distribute the incoming shock)
- Let your beak absorb the shock (Reduce the impact on brain)
- Turn your head when you peck (Redistribute the shock)
2
Q
What are the three major arteries that provide the cerebrum with blood?
A
- Anterior cerebral artery.
- Middle cerebral artery.
- Posterior cerebral artery.
3
Q
What is a stroke?
A
The sudden appearance of neurological symptoms because of severe interruption of blood flow.
4
Q
What are the statistics related to stroke in Canada?
A
Every 10 minutes someone in Canada dies from heart disease or stroke.
Stroke costs the Canadian economy $3.6 billion every year.
741,800 Canadians are living with long-term stroke disability.
5
Q
What are the two major classes of stroke?
A
- Ischemic stroke: blocked blood vessel, more common, less severe.
- Hemorrhagic stroke: burst blood vessel, more severe, fortunately less common.
6
Q
What are common symptoms of a stroke?
A
Weakness on the contralateral side of the body, slowed behaviour, short-term memory problems, vision problems, loss of coordination and balance.
7
Q
What is the goal of stroke treatment?
A
To restore normal blood flow ASAP.
8
Q
What is tissue plasminogen activator (t-PA)?
A
A treatment that breaks down the clot causing the stroke.
There is a 3-hour window during which the treatment is effective.
9
Q
What are the effects of a stroke?
A
Over-excitation of neurons, increase in protein production, inflammation of brain tissue, diaschisis (neural shock), changes in metabolism.
10
Q
What is constraint-induced therapy to treat stroke effects?
A
A therapy that binds the intact limb, forcing the patient to use the affected limb.
11
Q
What are the two main types of cells in the brain?
A
- Neurons: carry out the brain’s major functions.
- Glial cells: aid and modulate the neuron’s activities.
* Cell bodies and capillary blood vessels comprise the gray matter
* Myelinated axons comprise the white matter
12
Q
What are the six layers of the neocortex?
A
- Info integration: Layer I to III.
- Sensory Input (afferent): Layer IV.
- Output (efferent) info: Layer V to VI.
13
Q
What is the role of the spinal cord?
A
Involved in movement production, receives and sends info to and from the entire body
Often in conjunction with the brain, but not always:
Patellar Reflex
Locomotion – central pattern generators
The segments of our bodies (dermatomes) correspond to segments of the spinal cord.
* Each dermatome has a sensory nerve and a motor nerve associated with it.
14
Q
What is the Law of Bell and Magendie?
A
Sensory info is transmitted to the brain (afferent) in the dorsal portion of the spinal cord.
Motor info is transmitted from the brain (efferent) in the ventral portion of the spinal cord.
15
Q
What are the three divisions of the brain?
A
- The hindbrain.
- The midbrain.
- The diencephalon.
16
Q
What comprises the hindbrain?
A
Cerebellum, medulla, pons, and reticular formation.
17
Q
What is the function of the cerebellum?
A
Control of complex movements.
18
Q
What is the role of the reticular formation?
A
Responsible for stimulating the forebrain, arousal, sleep/wake behaviour.
19
Q
What is the function of the thalamus?
A
Acts as the ‘gateway to the cortex’, relaying sensory information to appropriate areas in the cortex.
20
Q
What does the hypothalamus control?
A
Controls hormone production via interaction with the pituitary gland (the master gland).
Including feeding, sex, sleep, sex, temperature regulation, sex, emotional behaviour, and sex, etc.
21
Q
What are the main structures of the limbic cortex?
A
- The amygdala.
- The hippocampus.
- The cingulate cortex.
Memory, spatial navigation, emotion, and motivation.
22
Q
What is the role of the Olfactory system?
A
Sends information from the olfactory bulb to the pyriform cortex.
Relative to other animals (cats, dogs), the olfactory bulb in humans is small.
23
Q
What is the function of the diencephalon?
A
Top of the brainstem, responsible for integrating sensory and motor information on its way to the cortex.
24
Q
What is the function of the amygdala?
A
Emotional memory.
25
What are the three divisions of the forebrain?
1. The Cortex
2. The Basal Ganglia
3. The Olfactory System
Largest region of the mammalian brain
26
What is the function of the hippocampus?
Spatial navigation and episodic memory.
27
What are the two divisions of the Autonomic Nervous System?
1. Sympathetic – arousal 'fight or flight'.
2. Parasympathetic – calm 'rest and digest'.
28
What is the Enteric Nervous System?
Largely independent of the ANS.
200 – 500 million neurons
Controls of digestion, bowel motility, blood flow, etc.
ENS sends info to the brain and can influence mental state
– Stress
– Anxiety can modify gut function leading to symptoms like nausea and diarrhea.
ENS interacts with gut bacteria, known as the microbiome
29
What are chromosomes?
Chromosomes are 'matched pairs' (one from your mother, one from your father).
30
What is an allele?
Alleles are matching copies of a gene.
## Footnote
Matched does not necessarily mean identical!
31
What is wildtype?
Wildtype is the most common (normal) phenotype or genotype.
32
What is phenotype?
Phenotype is the appearance of an organism that results from the interaction of genes with one another and the environment.
33
What is genotype?
Genotype is the full set of genes that a given organism possesses.
34
What is a mutation?
A mutation is any alteration of an allele that yields a different version of that allele.
35
What is a dominant allele?
A dominant allele is routinely expressed.
e.g., Huntington's Disease is caused by a dominant allele.
36
What is a recessive allele?
A recessive allele is routinely unexpressed.
e.g., Tay-Sachs disease is caused by a recessive allele.
37
What is Huntington's Disease?
Huntington's Disease is a neurodegenerative disorder that results in motor and cognitive disturbances.
Huntington's Disease typically shows up in mid-adult life (35 years +).
38
What defect is associated with Huntington's Disease?
Defect in the huntingtin gene, resulting in the build up of an abnormal version of the huntingtin protein.
Specifically, an increase in the number of CAG (cytosine-adenine-guanine) repeats on chromosome 4
Results in brain cell death.
* Basal Ganglia
* Cortex
39
What is CRISPR?
CRISPR stands for 'Clustered regularly interspaced short palindromic repeats' and is a form of acquired immunity.
Scientists use it to selectively remove or add DNA by altering genes/alleles
40
What is the role of Cas9 in CRISPR?
Cas9 is an enzyme that snips DNA.
41
What is the significance of creating knockout animals?
Creation of knockout animals allows for selective removal of a given gene, much faster than traditional approaches.
42
What is the role of Brain Derived Neurotrophic Factor (BDNF)?
BDNF is a protein that is important for the health of neurons.
43
What are the two versions of the BDNF gene?
The two versions of the BDNF gene are Val allele (most common) and Met allele (produces a slightly less effective form of the BDNF protein).
44
What is epigenetics?
Epigenetics examines the influence on our gene expression related to environment and experience.
Do not alter genes per say, rather allow or prevent their expression
e.g., childhood trauma, silences gene necessary for cortisol control
45
What are the mechanisms of alteration of gene expression?
The mechanisms include histone modification, DNA modification, and mRNA modification.
46
What is the resting potential of a neuron?
The resting potential is an electrical charge across the cell membrane in the absence of stimulation, approximately -70 millivolts (mV).
47
What ions are responsible for the resting potential?
Sodium (Na+) and chloride (Cl-) are higher in concentration outside the cell, while potassium (K+) and large proteins (A-) are higher inside the cell.
48
What is an action potential?
An action potential is a large, brief reversal in polarity of an axon that lasts approximately 1 millisecond (ms).
49
What is the threshold potential?
Threshold potential is the voltage on a neural membrane at which an action potential is triggered, approximately -50 mV relative to the extracellular surround.
50
What are voltage-sensitive ion channels?
Voltage-sensitive ion channels are gated protein channels that open or close only at specific membrane voltages.
51
What is myelination?
Myelination is produced by oligodendroglia in the CNS and Schwann cells in the PNS, acting as insulation and speeding up neural impulse.
52
What is saltatory conduction?
Saltatory conduction is the propagation of an action potential at successive nodes of Ranvier, resulting in a faster signal.
The process by which an electrical impulse jumps from node to node along a myelinated axon. This process is faster and more efficient than conduction in unmyelinated axons.
The impulse jumps between nodes of Ranvier, which are the uninsulated gaps in the myelin sheath, and regenerates at each node of Ranvier
53
What is the role of neurotransmitters?
Neurotransmitters are chemicals released by a neuron onto a target, with an excitatory or an inhibitory effect.
54
What is the structure of the synapse?
The synapse consists of presynaptic and postsynaptic membranes, with neurotransmitters stored in synaptic vesicles on the presynaptic side.
55
What is a gap junction?
A gap junction is a fused prejunction and postjunction cell membrane in which connected ion channels form a pore that allows ions to pass directly from one neuron to the next.
56
What is Behaviour?
Action, observable but fleeting. Patterns in time (i.e. thinking).
57
What is the Brain?
A physical object, living tissue and organ. The brain can be conscious in the absence of much overt behaviour or cues from the environment.
58
Why study Brain and Behaviour?
It's cool and there is much to explore.
e.g., The Case of Clive Wearing (had encephalitis which damaged his brain and made him unable to form new memories).
Brain can be conscious in the absence of much overt behaviour
In the absence of much sensory experience and movement, it can communicate through signal generated by its activity
59
What are the three broad historical approaches to brain and behaviour?
1. Mentalism
2. Dualism
3. Materialism
There is considerable debate as to which explanation is correct (mostly between dualism and materialism).
Most scientists (but not all) are materialists, “The mind is brain in action”
Materialists believe that all concepts of mind, consciousness, spirit can be reduced to the workings of the brain as a physical entity (orchestrated firing of neurons)
60
What is Mentalism?
Aristotle (384 – 322 BC) believed that behaviour was a function of the nonmaterial mind (mind is immaterial, abstract concept)
Believed the brain cooled the blood and had no role in producing behaviour.
Psyche: a synonym for mind; an entity once proposed to be the source of human behaviour.
61
What is Dualism?
René Descartes (1596 – 1650) believed there were two types of “stuff” in the world, physical and non-physical.
He believed that both a nonmaterial mind and the material body contribute to behaviour.
Mind is unique to humans...
Proposed that information between the mind and body passes through the brain.
This occurs via the pineal gland, which sits beside the brain’s fluid-filled ventricles.
Mind regulates behaviour by directing the flow of ventricular fluid to the muscles.
Some issues with Cartesian Dualism:
* The pineal gland is involved in biological rhythms, but not in intelligence or behavioural control.
* Movement is not elicited via the flow of fluid from the ventricles.
* Nonmaterial influences on the body would violate the law of conservation of matter and energy.
62
What is Materialism?
Behaviour can be fully explained by the workings of the nervous system, without explanatory recourse to an immaterial mind.
Supported by the evolutionary theories of Alfred Wallace (1823 – 1913) and Charles Darwin (1809 – 1882).
Both of whom were struck at the many similarities among species.
63
What is Darwin's Theory of Natural Selection?
Survival of the fittest: Differential success in reproduction results from the interaction of organisms with their environment.
New species evolve, and existing species change over time.
64
What are the implications of evolution for brain and behaviour?
1. All animal species' brains are related; as such, we can use simpler animals to understand humans.
2. All animal species' behaviour is related; emotional expression in humans (across cultures) and other animals is similar.
3. Brain and behaviour in complex animals such as humans evolved from simpler animals’ brains and behaviours and also depend on learning.
65
What are the two divisions of the human nervous system?
1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)
66
What does the Central Nervous System (CNS) consist of?
The brain and the spinal cord.
Anything that is encased in bone.
67
What does the Peripheral Nervous System (PNS) consist of?
All the nerve cells (neurons) in the body that are located outside of the CNS.
Two major divisions:
1. Somatic division: sensory info in, motor info out
2. Autonomic division: governs the workings of internal organs (heartbeat, respiration, etc.)
68
What are the four lobes of the brain?
1. Temporal Lobe: Hearing, Language, Memory
2. Frontal Lobe: Executive functions, Decision making
3. Parietal Lobe: Goal-directed movement, Integration of sensory info
4. Occipital Lobe: Vision
69
How do we define behaviour?
OED - 'the way in which an animal or person acts in response to a particular situation or stimulus'.
Eibesfeldt (1970) defines it as 'behavior consists of patterns in time'. E.g., movements, vocalizations, thinking, etc.
70
What is the Principle of Proper Mass?
Species exhibiting more complex behaviours will possess relatively larger brains.
Jerison developed an index of brain size to allow comparisons among different species.
Used body size to predict brain size.
As body size goes up the brain increases approximately 2/3 the increase of body weight
71
What is the Encephalization Quotient (EQ)?
Measure of brain size obtained from the ratio of actual brain size to the expected brain size for an animal of a particular body size.
Humans have the largest EQ (because based on our body size, one would expect our brains to be smaller than they are)
Below 1.0, assumed that you have a smaller brain when compared to your body size, and vice versa for above 1.0
EQ works well in most instances, but not always (e.g., blue whales with very large body size)
72
What are some factors associated with smaller brains?
Aging, Stress, Fetal Alcohol Spectrum Disorder (FASD), Autism Spectrum Disorder (ASD).
73
What are some factors associated with larger brains?
Autism Spectrum Disorder (ASD), Good nutrition during development, Larger body size, Plasticity, Enriched environments, Learning.
74
What did Charles Spearman propose?
Single factor theory, which he called g (general intelligence).
75
What did Howard Gardner suggest?
There are multiple different intelligences.
76
What did scientists at the University of Washington discover about crows?
Crows remembered the masks of their captors and even the next generation of crows displayed similar behaviour.
77
What are the three planes used to look inside the brain?
1. Coronal 2. Horizontal 3. Sagittal
78
What are the layers protecting the brain?
1. Duramater 2. Arachnoid layer 3. Piamater
79
What is Meningitis?
Inflammation of the meninges, which can lead to headache, stiff neck, drowsiness, stupor, coma, and death.
80
What is Cerebrospinal Fluid (CSF)?
The space just below the Arachnoid layer (the subarachnoid space) is filled with cerebrospinal fluid (CSF).
CSF is made up of salts (sodium and potassium chloride, etc.) in solution.
81
What happens in a concussive event?
1. Damage occurs at the site of impact (coup)
2. Damage occurs opposite the site of impact (countercoup),
3. Trauma causes axons to twist and tear, result is death of brain cells, this is long term damage. Leads to reduced cognitive function and behavioural consequences.
82
What is Chronic Traumatic Encephalopathy (CTE)?
The result of multiple concussions, leading to atrophy of the brain (likely a result of neuronal death), enlargement of the ventricles, and an increase in brain proteins associated with Alzheimer’s Disease.
83
What are the four major functions of CSF?
Four primary functions:
1. Buoyancy: helps to keep the brain “afloat”, the weight of the unsuspended brain would damage the neurons on the ventral surface.
2. Protection: protects the brain from injury (to a certain extent).
3. Chemical Stability: removes waste products associated with metabolic activity.
4. Prevention of ischemia (reduced blood flow and therefore, oxygen): decrease in CSF inside the skull decreases intracranial pressure, aiding blood perfusion
84
What does packing density refer to?
A method of estimating the number of brain cells in a given species
We look at the number of cells (neurons) that are packed in a given unit of space (we estimate packing density)
More tightly packed, more complex brains
Better method than Encephalization Quotient (EQ)
85
What is Toxoplasmosis?
Illness caused by a parasite primarily found in cats
* May be transmitted to humans.
* Route of transmission: cat
feces.
Symptoms:
* Headaches
* Fever
* Fatigue
* Muscle aches
* Confusion
* Seizures
* Encephalitis
86
What Are The Units Of Nervous-System Function?
A great debate in the early 1900s: What exactly are neurons?
Two opposing views:
1. Camillo Golgi:
- Golgi believed that the nervous system is composed of a network of interconnected fibers: a “nerve net”
- Human pyramidal neurons stained using the Golgi technique
- Golgi looked at the pictures and thought they resembled a
“nerve net”
- Cajal was not convinced
2. Santiago Ramón y Cajal:
- Cajal believed that the nervous system is made of discrete cells
- “Neuron Hypothesis” – neurons are the units of brain function
- Decided to examine a simpler system, the chick embryo
87
What are the four basic tenets of the Neuron Doctrine?
1. The basic, functional unit of the nervous system is the neuron.
2. Neurons are discrete cells.
3. The neuron is composed of 3 parts (the dendrites, the cell body, and the axon)
4. Information flows along the neuron in one direction
88
What three parts is the neuron comprised of?
1. Dendrites
* Gathers information from other neurons.
2. Cell Body or Soma
* Integration of information.
3. Axon
* Carries information to be passed on to other cells
89
What are dendritic spines?
Protrusions from a dendrite, the usual point of contact with axons of other cells.
90
What is an axon hillock?
Juncture of soma and axon where the action potential begins
91
What is a synapses?
Junction between one neuron and the next (Site of information transfer)
92
What are the features of an axon?
Axon collaterals: branch of an axon
These branches have ends, referred to as Teleodendria.
Terminal buttons (end feet): knob at the tip of the axon, conveys information to other neurons
93
What are the three basic types of neurons?
1. Sensory Neurons
- Bring information to the central nervous system
- Structurally, very simple.
- e.g., Bipolar neuron – found in the retina, conduct afferent info to the visual centres of the brain.
- e.g., Somatosensory neuron – afferent info into the spinal cord.
2. Interneurons
- Associate sensory and motor activity within the central nervous system
- Much more complex, why is that?
- e.g., Pyramidal cell – long axon, two sets of dendrites.
- e.g., Purkinje cell – extremely branched dendrites, info from the cerebellum to the rest of the brain.
3. Motor Neurons
- Send signals from the brain and spinal cord to muscles
- Complex dendrites, long axons that connect to muscles.
- Located in the lower brainstem and spinal cord.
94
How do neuron signals work?
The incoming signal is analog – graded signal (summation of input).
The outgoing signal is digital – on or off (binary).
95
How is it that neurons talk to one another?
Each neuron receives thousands of excitatory and inhibitory signals every second.
Neurons sum these signals and respond accordingly.
From the simple “yes-no” language of neurons emerges enormous possibilities for behaviour.
Mostly excitatory input = ACTIVE
Mostly inhibitory input = NOT ACTIVE
96
What is the function of glia cells?
Support cells within the nervous system.
1. Act as “nerve glue” (glia = glue), holding neurons in place.
2. Supply nutrients to neurons.
3. Act as insulation around axons.
4. Remove pathogens and dead neurons.
97
What are the five types of glia cells?
1. Ependymal Cell:
- Small, ovoid cells, found in the walls of the ventricles.
- Make and secrete cerebrospinal fluid (CSF).
2. Astrocyte
- Star shaped, relatively symmetrical.
- Responsible for providing structural support for neurons.
- Transports substances between neurons and capillaries.
- Scar tissue formation, sealing off the damaged area, promoting healing.
- Dilate blood vessels to provide more blood (and thus nutrients etc.) for active brain regions.
3. Microglial Cell
- Small, mesodermally derived, defensive function,
4. Oligodendroglia Cell
- Asymmetrical, forms myelin around axons in brain and spinal cord
5. Schwann Cell
- Asymmetrical, wraps around peripheral nerves to form myelin
98
What is the blood-brain barrier?
Protective barrier formed by astrocytes in combination with blood vessels.
Prevents toxins etc. from entering the brain.
Also prevents useful substances from getting through (antibiotics etc.).
The blood brain barrier protects the entire brain, with the exception of a few areas
99
What is Multiple Sclerosis (MS)?
An autoimmune disease: illness resulting from an abnormal immune response by the body against substances and tissues normally present in the body
Possible environmental factors (lack of Vitamin D) and genetic components (you are more likely to get it if someone in your family has it)
In 2017, the drug OCREVUS became the first drug to be approved by the FDA for primary progressive MS (It significantly slows the progression of MS by selectively targeting a single component of the immune response (B cells)
Recent research aims to promote repair or remyelination (i.e. PIPE-307)
100
What Goes on Inside a Neuron?
Neurons are simply a specialized type of cell.
Cells produce proteins!
Several components within the cell, called organelles, aid in protein production,
e.g., golgi bodies, lysosomes, nucleus, etc.
101
What is the cell membrane?
The cell membrane separates the inside and the outside of the cell.
Semi-permeable: only select substances can pass through the membrane.
The membrane is comprised of phospholipids:
* Hydrophilic head: phosphate group (binds to H20)
* Hydrophobic tail: lipids (fat, won’t bind to H20)
102
What is kept in the cell's nucleus?
Blueprints for protein production are kept (genes).
Genes: segments of DNA that encode the synthesis of particular proteins.
Genes are contained within chromosomes
103
What are the two main processes of protein synthesis?
1. Transcription
- Early phase of protein synthesis in which the DNA strands unwind and a complementary strand of messenger RNA (ribonucleic acid) is created.
- Takes place in the nucleus
2. Translation
- Later phase of protein synthesis in which the
messenger RNA (mRNA) travels from nucleus to the Endoplasmic Reticulum (rough ER)
- Endoplasmic Reticulum: structure just outside the nucleus that contains ribosomes.
- Ribosomes: protein structures that act as catalysts for protein synthesis.
- mRNA is translated by the Ribosome into a particular sequence of amino acids to form a protein.
Flows from DNA to mRNA using transcription, then from mRNA to amino acids using translation, results in protein
104
What are transmembrane proteins?
- Ions can cross a cell membrane through the appropriately shaped channel
- A gated channel changes shape to allow passage of substances when gates are open, and to prevent passage when one or both gates are closed
- A pump transported changes shape to carry substances across a cell membrane
