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Intro to Psyc McGill (PSYC 100 - 2022 fall) > L06 - Neurobiology > Flashcards

L06 - Neurobiology Flashcards

1
Q

Components of the Central Nervous System?

A

Brain and Spinal Cord

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2
Q

Components of the Peripheral Nervous System?

A

Sommatic Nervous system (SNS) and the Autonomic Nervous System (ANS)

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3
Q

What does the Somatic Nervous System do?

A

Controls communication between areas of the body and the CNS. (Skin, muscles and joints send signals to the spinal cord and the brain and vice versa) Links muscles and joints to CNS

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4
Q

What does the Autonomic Nervous System do?

A

Regulates internal environment of the body and the unconscious.
Stimulates glands (ex. sweat glands) and internal organs (ex. heart, liver…) nerves of ANS send signals to the spinal cord and brain and vice versa.
Separated into two systems that counteract each other; the Sympathetic and the Parasympathetic nervous systems

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5
Q

What do the Sympathetic and the Parasympathetic nervous systems do? (Not the difference - what do they do?)

A

They counteract each other. They contain algorithms to set up the body for certain situations rapidly. They are linked to the glands and inner organs since they are a part of the Autonomic Nervous System.

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6
Q

What does the Sympathetic do?

A

The Sympathetic Nervous System prepares the body for action. Ex. (sees threat, activates body perfectly for the situation) if you see a predator and have to run away, this system will constrict your blood vessels so you can run faster, change your lung capacity, stop your digestive system and give everything possible to your muscles that allow you to run faster. CHRONIC STRESS leads to increased activity of this system.

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7
Q

What does the Parasympathetic Nervous System do?

A

Resets the body to normal mode after the “action mode” of the Sympathetic Nervous System.

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8
Q

What is the Endocrine System?

A

An alternative signalling pathway system to the nervous system. RUNS ITS CONTROLS THROUGH HORMONES. It is much slower than the nervous system because hormones need to be released in the blood stream and circulate systematically until it reaches its target. It is connected to the nervous system but it does not run its controls through nerves.

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9
Q

What does the Endocrine System do? (HPA axis)

A

The hypothalamic-pituitary-adrenal axis, or HPA axis, is a term used to represent the interaction between the hypothalamus, pituitary gland, and adrenal glands; it plays an important role the body’s response to stress. The pathway of the axis results in the production of cortisol.

When CRF binds to CRF receptors on the anterior pituitary gland, adrenocorticotropic hormone (ACTH) is released. ACTH binds to receptors on the adrenal cortex and stimulates adrenal release of cortisol. In response to stressors, cortisol will be released for several hours after encountering the stressor. At a certain blood concentration of cortisol this protection is ostensibly achieved and the cortisol exerts negative feedback to the hypothalamic release of CRF and the pituitary release of ACTH (negative feedback). At this point, systemic homeostasis returns.

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10
Q

Chronic vs. Acute Stress

A

Chronic Stress - comes from situations that give you the perceptions of stress and the body is told constantly that it is in danger when it is not – comes from chronic pain, PTSD, poverty( Long-term effects on corticosteroids – suppress immune system (good for short-term but very bad for long-term) )Constantly upregulated immunosuppression situation can cause cancer (Normal immune system can deal with cancerous cells but chronic stress causes cells to make copy errors)

Acute Stress - is good for the body – optimizes your performance in some situations

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11
Q

Ramon Y Cajal

A

Worked in Spain and made drawings of what he saw in brain slices under a light microscope. What he found was fundamental because up to this day, people thought the brain was just like any other organ that was continuous and a mass of tissue together but found that neurons were not like anything else in the body and they are never directly connected .

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12
Q

Form always dictates function.

A

Neurons are specialized in communicating

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13
Q

Neurons of CNS glial cells

A

Much more abundant than the brain neurons??

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14
Q

What are MICROGLIA neurons?

A

They are mobile - move around the brain and repair damages (ex. Stroke - microglia neurons spring to action to keep system under control - cannot slavage dead neurons but can repair damaged tissue)

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15
Q

What are the two types of MACROGLIA neurons?

A

Astrocytes and oligodenrocytes

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16
Q

How do Astrocytes work/what do they do?

A

They link neurons to blood vessels forming part of the blood-brain barrier. They engulf synapses (where neurons connect) regulating neurotransmitters release during synaptic transmission. *Critical for forming memories, part of the most complicated things the brain can do (plasticity, changing its shape, learning from new experiences)

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17
Q

How do Oligodendrocytes work/what do they do?

A

They surround axons in the CNS forming the myelin sheath that insulates axons, which ALLOWS THE ELECTRICAL SIGNALS THAT TRAVEL IN THE AXON TO TRAVEL FASTER. *Essential for the function/development in neurons. THEY ARE ISOLATORS - IF YOU LOSE OLIGODENDROCYTES YOU SLOWLY STOP MOVING AND DIE.

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18
Q

How does information flow in reflexes? (a reflex is when you touch something and it hurts so you take it off quickly)

A
  1. Mechanoreceptors in the skin detects energy.
  2. Sensory neurons fire along the nerves and go to CNS (spinal cord)
  3. Spinal cord - reflex pathway built in (no need to go to brain - not enough time)
  4. Motor neurons innervate the muscle (gives info) making the muscle send signal to make (ex. muscle tells you to take your hand off of something burning)
  5. (i,e.) Bicep contracts
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19
Q

Describe the anatomy of a neuron.

A

SOMA - cell body, where the nucleus/DNA is
DENDRITES - “Branches”; input sector (recieves signals from other neurons here)
AXON - one long fiber; output fiber (where a neuron SENDS signals)
AXON TERMINAL - connections to other neurons (to dendrites of other neurons) can be made through synapses here
SYNAPSES - Pre-synaptic and post-synaptic cells, do not let neurons touch *Usually wrapped in astrocytes (microglia cell - protecting CNS neurons)
MYELIN SHEATH - isolates the axon (wraps around the axon) to protect it. Important for the development that allowed modern forms of behaviour to emerge. *oligodendrocytes (microglia cell - protecting CNS neurons)

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20
Q

What are Action Potential terms?

A

Electrical potential - how much energy is stored up in a system
Potential - something that can be. When a neuron is not active, the electrical charge inside and outside are different and this difference is called a potential.

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21
Q

What is Resting Potential?

A

A neuron lying around doing nothing. A neuron has a resting potential of -70 millivolts (negative in front)

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22
Q

What is the Action Potential?

A

A brief change in resting potential. This is triggered if an electrical stimulation is strong enough and exceeds the threshold of excitation so the axon of the stimulated neuron will fire an action potential.

During the action potential, the neuron is briefly depolarized, so the membrane potential reaches about +40 mV. (inside gets filled with positive particles)

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23
Q

What is diffusion?

A

Particles tend to move from a region of high concentration to a region of low concentration eventually reaching equilibrium. (system tries to reach lowest form of energy) *caused by Brownian movement

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24
Q

What is Brownian Movement?

A

Random moving of particles (bump each other by accident sometimes. Causes Diffusion.

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25
Q

What is the permeable membrane?

A

Membrane that only lets specific particles go thorugh.

26
Q

What is Electrostatic pressure?

A

“Opposites attract”. Particles with different charges (+ and - ) are attracted to each other and “same” repel each other.

27
Q

What does the Na/K pump look like at resting potential?

A

More negatively charged ions (Cl-) are on the inside while more positively charged ions (Na+/K+) are on the outside.

28
Q

What is the Lipid Bilayer?

A

Fat molecule (specific form - double layer)

29
Q

What devices link the inside world of the neuron to the outside world?

Hint: The neurons would be completely isolated from the outside world if it wasn’t for this.

A

The receptors on the channels. They are free-floating (some static and others floating)

30
Q

Describe what happens in the Action Potential.

Side note - action potential occurs at the beginning of the axon (close to the Soma)

A
  1. Na+ channels open, Na+ begins to enter the cell
  2. K+ channels open, K+ begins entering the cell
  3. At the very top of action potential graph Na+ channels become refractory, no more Na+ enters the cell
  4. As graph going down K+ continues to leave cell causeing membrane potential to return to resting level
  5. At bottom K+ channels close, Na+ channels reset
  6. Below line Extra K+ outside diffuses away

Sodium chanels are voltage dependent channels. they open and Na+ rushes into neuron (driven by force of diffusion and electrostatic pressure). This depolarizes the neuron membrane potential

When depolarization reaches a point close to 0 mV, potassium channels open, K+ leaves neuron due to force of diffusion (less K+ outside) and driven by electrostatic pressure from inside due to increase in positive charge from Na+ infllux.

When depolarisation reaches about +40mV, the sodium channels enter a refractory state and close: no more Na+ can enter the neuron.

The forces of diffusion and electrostatic pressure continue to force K+ out of the neuron. This reduces the positive charge inside the neuron, repolarising it, i.e., driving down the membrane potential.

When potential reaches resting potential, K+ channels close.

There is a slight hyperpolarisation the end, neuron reaches -70mV. Sodium-potassium pumps restore resting potential

31
Q

How does the Action Potential lead to a neuron firing?

A

Stimulating a neuron - giving it input (from another neuron through the synapses)

Unstimulated neuron’s Na+ channels are closed.

Then the action potential causes the Na+ channels to open. The threshold potential is reached at axon hillocj. Na+ channels open

Entry of Na+ depolarizes the membrane and opens channels towards the axon terminal. Previously opened Na+ channels are inactivated (see page 190 in notability)

Continued entry of Na+ depolarizes the membrane and opens channels farther down the axon. Previously opened Na+ channels switch to a close state when K+ channels open and restore the resting potential.

Process continues and action potential moves down axon

32
Q

What does the Saltatory signal (leap/jump) propagation do to help along myelinated axons?

A

The speed of travel inside the neuron is not very fast. It is about 1 meter per second which means reflexes would not be very fast. However, the saltatory signal found a way to speed it up.

Myelin sheath is wrapped around by oligodendrocytes that are not continuous. (Nodes of Ranvier are the spaces between myelin sheath - where cell membrane is exposed to extracellular space)
- the saltatory signal speeds up the process by jumping ahead to each Node of Ranvier

This speed it up about 100X which allows you to react very fast to things and receive signals faster. (reflexes)

33
Q

Does the diameter of the axon have an influence on the speed of signals?

A

YES! Making the diameter of the axon thicker makes it FASTER. This is because there are more possible paths through the mess of organic matter for charge to diffuse.

34
Q

What is the influence agonists have on modulating neurotransmission?

A

Agonist drugs can INCREASE how much neurotransmitter is made, so there is more inside each vesicle. They can block the reuptake of neurotransmitters and have more available enhancing the signal again. (they can mimic a particular neurotransmitter binding to that neurotransmitter’s post-synaptic receptors and either activating them or increasing the neurotransmitter’s effect.)

35
Q

What is the influence antagonists have on modulating neurotransmission?

A

Antagonist drugs can DECREASE the release of neurotransmitters so there are fewer inside each vesicle. They can help DESTROY neurotransmitters int the synapses. (They can mimic a particular neurotransmitter binding to that neurotransmitter’s post-synaptic receptors enough to block neurotransmitter binding)

36
Q

Major Neurotransmitters

A

Glutamate - Excitatory (learning and movement)
GABA - Inhibitory (learning, anxiety, regulation through inhibition of neurons)
Acetylcholine - Excitatory (learning, muscle action)
Dopamine - Excitatory/Inhibitory (learning, reward, pleasure)
Seretonin - Excitatory (elevation/depression of mood)
Nonepinephrine - Excitatory (elevation/depression of mood)
Enkaphalins/Endorphins - Excitatory/Inhibitory (regulation of pain responses)

37
Q

How many synapses does one neuron have?

A

One neuron has about 10,000 synapses (can receive 10,000 inputs at the same time - gives complexity of circuit)

38
Q

What is the release and bindings of neurotransmitters? (terminal button - end button of axon)

A

Neurotransmitter binding, depending on the transmitter and the receptor, can have a variety of outcomes. Some neurotransmitters can have inhibitory effect (like GABA); they make it less likely that the post-synaptic neuron will fire and other have an excitatory effect (like glutamate); they make it more likely that the post-synaptic neuron WILL fire.

  1. Transmitter is being synthesized and then stored in vesicles
  2. Action potential invades the pre-synaptic terminal
  3. Depolarization of pre-synaptic terminal causes opening of voltage-gated Ca+ channels
  4. Influx of Ca2+ through channels
  5. Ca2+ causes vesicles to fuse with pre-synaptic membrane
  6. Transmitter is released into synaptic cleft via exocytosis
  7. Transmitter binds to receptor molecules in post-synaptic membrane
  8. Opening and closing of post-synaptic channels
  9. Post-synaptic current causes excitatory or inhibitory post-synaptic potential that changes the excitability of the post-synaptic cell
  10. Retrieval of vesicular membrane from plasma membrane
39
Q

How does the knowledge about reuptake help us?

A

Psychiatrists know that depression is caused by a lack of seretonin and to increase this, they need to decrease the reuptake (recycling) of seretonin so more of them stay around. (SSRIs - selective seretonin reuptake inhibitors)

40
Q

What is the Hippocampus? What happens if this is affected?

A

The center for episodic memories / memories of events. It is the outer piece of the cortex and it looks like a sea horse. If this is broken - anmesia occurs (no new memories can be made) therefore, the hippocampus is essential for memories.

The hippocampus is close to the amygdala so it can make memories stronger/more important

41
Q

The size of the brain reflex the size of the “animal”. Why do the brains have folded shapes?

A

More folding means more space for a HIGHER NEURON COUNT.

42
Q

Who is Wilder Penfield?

A

One of Canada’s foremost neurosurgeons.
He opened the brain of awake patients and redrew the map of the brain. He treated epilepsy and found a couple of things out about the brain.
He operated on his own sister’s tumor and stimulated her brain while operating and the originated the known of stimulating

The brain has no pain receptors so doesn’t feel pain when getting touched.
The skull might have pain but they use anesthesia for that.
The last thing you want is to become; blind, deaf, paralyzed so before cutting things he found that you could ask the patients questions and gather information on how it is going. (ex. stimulate on area - patient smells roses or saw something…)

43
Q

What is the difference between the primary motor cortex and the primary somatosensory cortex?

A

The somatosensory cortex coordinates the sensory data that comes up from all over the body. It makes good usage of its close proximity to the parietal lobes and helps make up good hunters and skilled navigators in a world full of obstacles.

The motor cortex, as the name implies, coordinates our bodily movements (in strong relation with the cerebellum. Again, it’s proximity to the somatosensory cortex is highly logical. The smooth coordination between all these areas is what keeps us elegantly functional in day-to-day life situations.

44
Q

What is the Brain Stem? The Reticular Formation?

A

A part in the brain that contains the Midbrain, the Pons, the Medulla Oblongata, the Reticular formation and ends at the spinal cord. It houses nerves that are responsible for involuntary functions like sneezing, swallowing, urinating, orgasm and vomiting. Information like control centre for respiration (other autonomic functions) like breathing and helping the heart beat.

The Reticular Formation - projects into cerebral cortex, affects general alertness. Involved in sleep regulation and arousal.

45
Q

What does the Thalamus do?

A

The thalamus is gateway to cortex. With the exception of odour information, it receives all other sensory modalities. Smell, the oldest and most fundamental sense, has a direct route to the cortex.

During sleep, thalamus partially shuts down incoming sensory stimulations. (helps you sleep by blocking out noises)

Basically, receives all senses except for smell and it helps you stay asleep when you sleep.

46
Q

What does the Hypothalamus do?

A

Basically controls the body.
It is situated below the thalamus and it is INDISPENSABLE FOR SURVIVAL.
Receives afferents from almost EVERY part of the body and brain region.
Affects functions of many internal organs, regulates body temperature, blood pressure, blood glucose levels.
Involved in motivated behaviours (ex. thirst, hunger, aggression, lust)

47
Q

What does the Basal Ganglia do?

A

It is critical for planning and producing movement.
Afferents from the entire cerebral cortex. Efferents to motor centres of Brain stem.
Nucleus accumbens is part of the basal ganglia and it is important for reward processing and motivating behaviours. This involves dopamine activity in the nucleus accumbens.

48
Q

What do damages to the Basal Ganglia do?

A

Basal ganglia are critical for planning and producing movement.

Parkinson’s and Huntington’s disease cause the breakdown of this system

49
Q

What is the Amyglada responsible for?

A

Almond-like shaped

Plays a big role in our emotional responses, including feelings like pleasure, fear, anxiety and anger

Modulates processes in the hippocampus (and other brain regions), might signal importance of events, thus increasing their likelihood of being retained.

There is a direct path that goes from the retina to the amygdala (2-3 synapses) This is what allows us to be alert when we see something moving in our peripheral vision. Allows you to react faster

50
Q

What is the limbic system constituted of?

A

The hippocampus and the amyglada

51
Q

What is the cerebellum?

A

The “little brain”

Cerebellum is essential for motor learning and motor memory

Damage to the cerebellum causes head tilt and balance problems

Operates independently

Involved in planning event, memory, language and emotions

52
Q

Where are the primary motor cortex and the primary sensory cortex situated?

A

The primary motor cortex is situated in the frontal lobe and the primary sensory cortex is situated in the parietal lobe.

53
Q

What is the function of the Frontal Lobe?

A

Thought, planning, movement

Executive functions-does a lot (lots of personality traits managed here)

Phineas Gage-railway employee: through his skull frontal lobe and his personality changed

Deals chiefly with cognition and memory. Ability to concentrate, judgement, consequence analysis, problem solving, plan personality (including emotional traits)

54
Q

What is the function of the Parietal Lobe?

A

Touch, spatial relations

(the where pathway)

Represents sense processing; representation of the body, controls movement and receive touch signals/space processing

Plays an important role in integrating information from several senses. Also processes spatial orientation, some parts of speech, visual perception, and pain and touch sensations.

55
Q

What is the function of the Occipital Lobe?

A

Vision

Visual processing: where vision happens (not only here) representation of objects: very perceptually detailed representations of (i.e.) edges, lines…

Potentially where dreams start (seeing actually happens here)

The visual processing center of the brain. It contains most of what is referred to as the ”visual cortex”. It is also the part of the brain where dreams originate.

56
Q

What is the function of the Temporal Lobe?

A

Hearing, memory

(the what pathway)

Also has vision: peri rhinal cortex (outer layer) where objects are represented.

Objects you see require process here, MEMORY important here

The chief auditory receptive area and contains the Hippocampus, which is the chief region where long term memory is formed. Also deals with high-level visual processing (faces and scenes)

57
Q

What are the olfactory bulbs?

A

Nerves that triggers smells

58
Q

What is the optic chiasma?

A

Part of visual system

59
Q

What do the mammalian bodies do?

A

Important for memory

Ex. Causal coughs (alcoholics) disease if you are alcoholic long enough → drink too much, vitamin deficiency, DEGRADES the mammalian bodies

Makes people honest liars: Lose a lot of memories: notice something is not working when they tell you stories so they fill gaps with fantasy (to keep life consistent)

60
Q

What is the purpose of the brain stem (Pons/Medulla oblongata/Spinal cord)?

A

Important for autonomous functions like breathing, swallowing, sneezing, parts of heartbeat

61
Q

What is the Corpus Callosum?

A

Consists of millions of myelinated axons that connect the two hemispheres

The importance of this connection is apparent in split brain procedures

Without the corpus callosum, the hemispheres are prevented to talk to each other.

There is a treatment for epilepsy to cut the corpus callosum (split brain patients)

Cutting the corpus callosum prevents epilepsy to travel to the entire brain (seizures are way less bad)

62
Q

What is the contralateral hemispheric organization?

A

Split Brain

Only one eye sees something and that one side does not know what the other side saw

Because corpus callosum is the one that relates the information to the other side so if it is not there then it shouldn’t be transferring information

Intro to Psyc McGill (PSYC 100 - 2022 fall) (10 decks)

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