Revision (Level 4) Flashcards
What is neuroscience?
The field of science that studies the structure & function of the nervous system.
Which 2 subjects merge into 1 to form neuroscience?
Biology & psychology
At which levels can human behaviour be studied?
At the behavioural, organ, neural system, circuit, cellular, synaptic, and molecular levels.
What are examples of cells that can be used to study human behaviour?
Neurones and glia
How can cells contribute to our understanding of human behaviour?
Some of them are the building blocks of the CNS & others have specialised functions.
What is an example of a circuit that can be used to study human behaviour?
The myotatic spinal reflex (aka the ‘knee jerk’ reaction)
How can circuits contribute to our understanding of human behaviour?
Some of them can enable specific cell-to-cell communication
What are examples of systems that can be used to study human behaviour?
The motor, sensory & associational systems.
How can systems contribute to our understanding of human behaviour?
Some of them can tell us about the general state of an organism, as well as enable perception, movement & ‘higher order’ functioning.
What does our nervous system consist of?
Neurones (cells responsible for transmitting & receiving electrochemical information)
What do dendrites receive from other cells?
Messages
What do axons pass from the cell body to other neurones, muscles, or glands?
Messages
What is a neural impulse?
An action potential (an electrical signal travelling down the axon)
What is a cell’s life-support centre?
The cell body
What does myelin sheath cover?
The axons of some neurones
What does myelin sheath help speed up?
Neural impulses
What do the terminal branches of neurones form junctions with?
Other cells
What types of neurones are there?
Sensory, motor & interneurones
Which neurones carry incoming information from sense receptors to the CNS?
Sensory neurones
Which neurones carry outgoing information from the CNS to muscles & glands?
Motor neurones
Which neurones connect sensory & motor neurones?
Interneurones
What form circuits?
Interconnected neurones
Are circuits made up of interconnected neurones complex or simple?
Complex
How do circuits made up of interconnected neurones modify?
With growth and experience
What do complex neural networks look like?
They look like many cell bodies connected by axons, sending information to each other.
In the withdrawal reflex, what detect a painful stimulus?
Dendrites of the sensory neurone
In the withdrawal reflex, what does pain sensation travel down?
The axon of a sensory neurone.
What can happen to muscles in the withdrawal reflex?
They cause withdrawal from the source of the pain.
With what type of neurone does a sensory neurone synapse in the withdrawal reflex?
An interneurone in the spinal cord
In the withdrawal reflex, what type of neurone excites a motor neurone, causing muscular contraction?
An interneurone in the spinal cord
What causes the withdrawal of muscles from the source of pain in the withdrawal reflex?
A motor neurone in the spinal cord
What does the brain connect to?
The spinal cord
What type of neurones can inhibit motor neurones in the withdrawal reflex, preventing muscular contraction?
Interneurones from the brain
What extend from neurones in the brain through the spinal cord?
Axons of neurones
What does a cross-section of a spinal cord look like?
It looks like a butterfly shape inside of a lobed spherical structure.
What are the 2 parts of the nervous system?
The central & peripheral nervous system
What does the central nervous system consist of?
The brain & spinal cord
What are the 2 parts of the peripheral nervous system?
The autonomic & somatic nervous system
With what does the autonomic nervous system communicate?
Internal organs & glands
With what does the somatic nervous system communicate?
Sense organs & voluntary muscles
What are the 2 parts of the autonomic nervous system?
The sympathetic (arousing) & parasympathetic (calming) division
What are the 2 components of the somatic nervous system?
The sensory (afferent) & motor (efferent) nervous systems
What is the sensory nervous system responsible for?
Sensory input
What is the motor nervous system responsible for?
Motor input
In which part of the body is the central nervous system located?
In the upper & middle parts.
In which part of the body is the peripheral nervous system located?
In the upper, middle & lower parts of the body.
What can the naked eye distinguish?
Grey & white parts in the brain & spinal cord.
What is grey matter made up of?
The cell bodies of neurones.
What is white matter made up of?
The axons of neurones
Is the ‘butterfly-shaped’ part of the spinal cord made up of grey or white matter?
Grey matter
Is the ‘shell-shaped’ part of the spinal cord made up of grey or white matter?
White matter
What is the diameter of the spinal cord?
1 - 1.5 cm
What does the term ‘medial’ refer to?
Moving inward from the outer body area towards the spinal cord.
What does the term ‘lateral’ refer to?
Moving outward from the spinal cord towards the outer body area.
Towards where is the term ‘dorsal’ (superior/ posterior) referring?
Either the top of the brain or the back of the spine.
Towards where is the term ‘anterior’ (rostral) referring?
Either the front of the brain or the top of the spinal cord.
Towards where is the term ‘posterior’ (caudal) referring?
Either the back of the brain or the bottom of the spine.
Towards where is the term ‘ventral’ (inferior/ anterior) referring?
Either the bottom of the brain or the front of the spinal cord.
In which direction do the brain coordinates rotate as we move down the spinal cord?
Backwards
From a sideways (lateral) perspective, what is the largest visible sulcus in the brain?
The lateral sulcus
What part of the face & head would you cut to produce a horizontal plane?
Horizontally in between the eyes and nose.
What part of the face & head would you cut to produce a coronal (frontal) plane?
Vertically through each temple
What part of the face & head would you cut to produce a mid-sagittal (medial) plane?
Vertically through the middle of the face.
What are the 3 section planes?
The horizontal, coronal & sagittal planes.
What is the cervical spine?
The first 7 stacked vertebral bones of your spine
What is the forebrain?
The anterior part of the brain.
How could you describe what the medial view of the left hemisphere of the brain looks like?
It is the inside of one hemisphere of the brain and contains an unfinished loop-like structure and a (severed) tube at the bottom.
What does the thalamus serve as?
The brain’s main relay station.
What does the thalamus look like?
It sits under the unfinished loop-like structure in the brain and consists of a small sphere inside of a sperm-shaped structure.
What is the main function of the pineal body?
To receive information about the state of the light-dark cycle from the environment & convey this information by the production & secretion of the hormone melatonin.
What does the pineal body look like?
A small, round appendage attached to the unfinished loop-like structure.
What is the main function of the cerebellum?
Maintaining balance & posture
What does the medulla do?
It manages the heart, circulation & breathing.
What does the pons do?
It handles unconscious processes such as the sleep-wake cycle & breathing.
What does the tectum do?
It receives visual information in a spatially-arranged retinotopic map.
What does the tegmentum do?
It relays inhibitory signals to the thalamus & basal nuclei preventing unwanted body movement.
What does the tectum look like?
2 little hills just behind the tegmentum.
What does the tegmentum look like?
A cube-like structure just in front of the tectum.
What does the hypothalamus do?
It produces hormones that control body temperature, heart rate & hunger.
What does the hypothalamus look like?
A cube-like space underneath the thalamus.
Which 2 structures make up the midbrain?
The tegmentum & the tectum.
What is the brain?
The command centre of the human body
How much does the brain weigh?
3 pounds
What is an example of what the brain can do?
Store memories
How many neurones does the brain contain?
Around 86 billion
What are neurones?
Specialised cells that can communicate with each other using chemical & electrical signals.
How do groups of neurones link together to form neural circuits?
Via long connections called axons
What are organised differently in discrete brain regions that carry out different tasks?
Neural circuits
What interconnect to coordinate actions like guiding motor skills using visual information?
Different regions of the brain
What are glia?
Support cells which provide & maintain the optimal environment for the growth & interaction of neurones.
During neurotransmission, when does an action potential (AP) occur?
If the depolarisation of a cell membrane exceeds a particular threshold.
Are APs sudden & brief or long-lasting during neurotransmission?
Sudden & brief
How long do APs last during neurotransmission?
0.5 - 2 ms
What do APs momentarily reverse during neurotransmission?
Cell membrane potential
What quickly repolarises before overshooting during neurotransmission?
Cell membrane potential
Is the magnitude of an AP fixed or flexible during neurotransmission?
It’s fixed
What kind of response is an AP?
An all-or-nothing response
What governs the flux of Na+ & K+ ions into & out of cells during neurotransmission?
A complex cascade of opening & closing of voltage-gated ion channels.
In the process of an AP, do Na+ ion channels open before or after K+ channels?
Before
In the process of an AP, do Na+ ions flow into/ out of a cell?
Into the cell
In the process of an AP, do K+ ions flow into/ out of a cell?
Out of the cell
During which of the 5 stages of an AP are Na+ ion gates open during neurotransmission?
During stages 1 & 4
During which of the 5 stages of an AP are K+ ion gates open during neurotransmission?
During stages 2 & 4
During which of the 5 stages of an AP are K+ ion gates closed during neurotransmission?
During stage 5
During which of the 5 stages of an AP are Na+ ion gates closed during neurotransmission?
During stage 3
During which of the 5 stages of an AP is the inside of the cell more negative than the outside of the cell during neurotransmission?
During stages 1, 2, half of 4, and 5.
During which of the 5 stages of an AP is the inside of the cell more positive than the outside of the cell during neurotransmission?
During stage 3 & half of stage 4
During which of the 5 stages of an AP does Na+ enter a cell during neurotransmission?
During stages 1 & 5
During which of the 5 stages of an AP does K+ leave a cell during neurotransmission?
During stages 2 & 4
Which of the 5 stages of an AP is the refractory stage?
Stage 3
Which of the 5 stages of an AP is the reset stage?
Stage 5
Which of the 5 stages of an AP are the open stages?
Stages 1, 2 & 4
What is resting membrane potential?
-70 mV
Which channels become refractory in stage 3 of an AP during neurotransmission?
Na+ channels
What can no longer enter a cell in stage 3 of an AP during neurotransmission?
Na+
In an AP, what causes membrane potential to return to its resting level?
K+ leaving the cell
What diffuses away during stage 6 of an AP during neurotransmission?
Extra K+
What is the withdrawal reflex?
A neural circuit
What can be used to alter the potential of a membrane during neurotransmission?
An electrical stimulator
What can depolarise a membrane’s potential during neurotransmission?
Positive current
Do weak changes in the potential of a membrane during neurotransmission affect it or does this not do much?
It doesn’t do much
When is an action potential created?
When the potential of a membrane reaches the threshold of excitation.
What is an action potential?
A very rapid reversal of a membrane’s potential
Which law applies to action potentials?
The all-or-none law
What does the all-or-none law claim?
That action potentials either fire or don’t fire.
When is an action potential not affected by the size of a stimulus during neurotransmission?
When a membrane’s potential is above a certain threshold.
When a membrane’s potential is above a certain threshold during neurotransmission, how is stimulus intensity coded?
By the frequency of action potentials.
What do action potentials caused by a weak stimulus look like before & after the stimulus is present?
Vertical lines that occur infrequently along a main horizontal line.
What do action potentials caused by a weak stimulus look like while the stimulus is present?
Vertical lines that occur relatively frequently along a main horizontal line.
What do action potentials caused by a strong stimulus look like before & after the stimulus is present?
Vertical lines that occur infrequently along a main horizontal line.
What do action potentials caused by a strong stimulus look like while the stimulus is present?
Vertical lines that occur extremely frequently along a main horizontal line.
What can cause failed initiations of action potentials?
A stimulus
At what voltage is a membrane at its resting state?
-70 mV
What happens when a membrane’s potential exceeds -55 mV during neurotransmission?
The membrane depolarises & an action potential begins to occur.
What exists at a membrane potential of -55 mV?
A threshold
What enter cells during membranal depolarisation?
Na+ ions
What happens when a membrane’s potential reaches +40 mV during neurotransmission?
The membrane begins to repolarise
What happens after a membrane has been repolarised during neurotransmission?
It becomes hyperpolarised.
What leave cells during membranal repolarisation?
K+ ions
What happens after a cell membrane has been hyperpolarised?
It returns to its resting state.
What happens after an action potential has taken place?
There is a refractory period.
Are neuronal cell membranes permeable, impermeable, or semi-permeable?
Semi-permeable
What are neurones?
Information-processing devices
What happens during electrical neurotransmission?
Following sufficient stimulation of a neurone, an action potential is generated at the origin of the axon.
What happens during chemical neurotransmission?
When an action potential reaches an axon terminal, it stimulates the release of chemical neurotransmitters.
What are the 2 forms of neural communication?
Electrical neurotransmission & chemical neurotransmission.
What are synapses?
Gaps between neurones where signals are passed from 1 to the other during neural communication.
What are gap junctions?
Very small gaps (2-4 nm) between 2 neurones that occur in electrical synapses.
Which membranes have large channels that allow ions to move directly from 1 cell to the other in electrical synapses?
Those facing each other.
What is similar to action potential conduction along the axon?
How information is transmitted from 1 neurone to the other in electrical synapses.
Is neural communication across electrical synapses very fast or very slow?
Very fast (there’s no time delay)
What are rare in the human CNS?
Electrical synapses
What is the mechanism of neural communication in the CNS?
Chemical synapses
What are chemical synapses?
Structures specialised for the transmission of chemical signals from 1 neurone (presynaptic neurone) to another (postsynaptic neurone)
What is the synaptic cleft?
The gap between the axon of 1 neurone & the dendrite of the next one in chemical synapses.
How big is the synaptic cleft?
It’s small (20-40 nm)
How many chemical synapses does each neurone typically have?
Many (typically ca 1000)
Is neural communication via chemical synapses fast or slow?
Slow (ca 1 ms)
What do neuronal dendrites look like?
Squiggly, tree-like appendages.
What do neuronal cell bodies look like?
They’re spherical with rugged edges & a sphere in the middle.
What do neuronal axons look like?
Long, thin, cylindrical structures.
