Flashcards in Neuroscience Deck (45):
What are the two major divisions of the nervous system and what do they control?
Central nervous system - brain and spinal cord
Peripheral nervous system - motor nerves, autonomic nervous system, sensory nerves, enteric nervous system
In the peripheral nervous system what is the input/output of the two parts?
Sensory - input to cns from sensory organs
Motor - output from CNS to muscles
What is the function of the autonomic nervous system?
Controls many non-voluntary functions e.g. Digestion, heart rate sweating pupil size genitals
What are the two branches of the autonomic nervous system?
Sympathetic - prepares for action
Parasympathetic - involved in rest and recuperation
What is the enteric nervous system?
Controls digestive activity (peristalsis and secretion of enzymes) and sense physical and chemical conditions of the gut.
What are the brain and spinal cord protected by?
Bone, meninges, blood brain barrier
What is the meninges?
Flexible sheet made from 3 membranes, between bone and nervous tissue.
What are the 3 membranes of the blood brain barrier?
What is the function of the blood brain barrier?
Protect brain and spinal cord --> particular blood vessels that have special walls restricting entry of many chemicals.
What are the ventricles of the brain?
- cavities inside the brain, filled with cerebrospinal fluid
- sewage system of the CNS
What are the 7 major subdivisions of the brain?
Thalamus and hypothalamus
What can happen if damage occurs to the brain stem?
Coma and death due to increase in intracranial pressure squashing brain stem.
Where and what is the function of the cerebellum?
Top of brain stem - control of precision movements, densely packed with neurons.
What is the function or the limbic system?
Control of emotion and memory
What is the function of the basal ganglia?
Involved in action and thought - at any time variety of actions, basal ganglia determines what you do.
Where is the basal ganglia and neocortex located?
Basal ganglia - wraps around thalamus
Neocortex. - convoluted sheet on top of brain
Why is the neocortex convoluted?
- increased surface area
- thickness remains fixed.
What are the four lobes of the neocortex and what are their functions?
1. Frontal lobe - support planning and many executive decisions
2. Parietal lobe. - understanding space and how to move in it
3. Temporal lobe - memory and language
4. Occipital lobe - vision
What is the sophistication of our brain due to?
High speed of information AND complexity of connections between neurons.
What is the function of myelin?
Speeds up propagation of action potential
What have we learned from knowledge of neuronal function?
Certain Drugs work by interfering with action potentials e.g. Anaesthetics prevent opening of ion channels
What two types of neurotransmitters are there?
Excitatory - promote action potential in 2nd neuron
Inhibitory - block action potential
TMS (transcranial magnetic stimulation) studies the brain how?
- magnetic pulse to induce electrical current which depolarises neurons and provokes action potentials
What is the function of an EEG?
Electrodes plates against skull record elective all fields by activity of many neurons --> good temporal resolution poor spatial resolution
What does positron emission tomography measure?
Activity in Brain by measuring changes in Blood flow by using radioactive labelled glucose
How does PET work?
Records amount of oxygen in areas of the brain --> bad areas will draw more blood as they require more oxygen.
How does magnetic resonance imagine or MRI work?
Bombards head with high frequency radio waves measures orientation of protons - identifies different types of brain tissue.
What does fMRI measure?
Changes in oxygen in blood
What does magnetoencephalography (MEG)do and what does it measure?
Measures magnetic fields emitted from brain to create 3D visualisation of where electrical activity arises from --> creates functional map of brain response.
What keeps us awake?
Noradrenaline neurons, in locus coeruleus, serotonin neurons, and acetylcholine neurons in pons.
What is caused by destruction of the pre optic area?
Insomnia and stimulation can cause sleep.
What is sleep characterised by?
Rhythmic patterns of electrical activity in the brain.
What is rem sleep?
At multiple times through the night brain becomes desynchronised, rapid eye movement. If woken we typically report we are dreaming.
What is rem sleep caused by?
Caused by neurons in pons that contain acetylcholine and stimulates neurons in the thalamus, which project to the visual cortex.
What does the destruction of the lateral hypothalamus do in rats?
Stop eating dramatically.
Weight drops until rat begins eating but only a fraction of what is previously ate and weight becomes stable but much lower than before.
What is lateral hypothalamus feeding control by?
Controlling release of insulin
What does the destruction of the hypothalamus cause?
Rats - over eaters, making them gain weight quickly
However each meal is normal size but they eat more often
Are the two hemispheres mirror images of each other?
No - several higher functions are lateralised , one side is more important. Eg hand preference
What is the evidence for the lateralisation of language?
Stokes in left cause aphasia (problems with speech)
Brain imaging - left hem more active when person list be to speech
Dichotic listening task - people understand word better if presented to right ear.
What does damage to Broca's area cause?
Difficulties speaking and can understand speech.
What does damage to wernickes area cause?
Problems with comprehension - produces fluent but meaningless speech.
What is weird about split brain patients?
Still walk talk and suffer little impairments to intelligence or emotion but differences in what right and left hands do.
What is the most commonly know function of the right hemisphere?
What is hippocampal amnesia?
Damage to the hippocampus - remember old events but can't learn anything new.