The brain & the mind PART 1 Flashcards
What does the nervous system do?
aka body’s electrochemical communication network
- Gathers & processes info
- Produces responses to stimuli
- Coordinates operations of different cells
What does the nervous system comprise of?
Central nervous system (CNS)
Peripheral nervous system (PNS)
What does the CNS consist of?
Brain
Spinal Cord
CNS: central processing unit
What does the brain do (CNS)?
Interprets & stores info & sends orders to muscles, glands, organs
What does the spinal cord do (CNS)?
Pathway connecting brain & PNS
Collection of neurons & supportive tissue that runs frm base of brain down the back -> protected by spinal column
What does the PNS consist of?
Autonomic Nervous system (ANS)
Somatic Nervous system (SNS)
What is the PNS?
Transmit info to & from CNS
Contains ALL portions of NS (except brain & spinal cord)
Incl. sensory & motor nerves that connect CNS to rest of body
What does the ANS do?
- Controls functioning of internal organs, glands & bld vessels
- Usually operates on its own but may be CONSCIOUSLY overriden
What is multiple sclerosis & what does it cause?
Autoimmune disease that causes immune system to attack myelin sheath that covers peripheral nerves
Destruction of peripheral nerves
What does the ANS comprise of?
Sympathetic NS (arousing)
Parasympathetic NS (calming)
Work tgt but in opposing ways
What does the sympathetic NS do?
Mobilise body resources & inc. output of energy during emotion & stress
What does the parasympathetic NS do?
Enables body to conserve & restore energy
Slows things down
What are some examples of the sympathetic NS working on organs?
Just fyi;
- Dilate pupils
- Inc. HR
- Inhibits digestion (stomach & pancreas)
- Stim. glucose release by liver
- Stim. secretion of epinephrine/norepinephrine
- Relaxes bladder
What are some examples of the parasympathetic NS working on organs?
- Contracts pupils
- Slows HR
- Stimulates digestion
- Stimulates gallbladder
- Contracts bladder
What does the SNS control?
Body’s skeletal muscles
Voluntary processes
What does the SNS comprise of?
Sensory input - carry messages frm senses to CNS
Motor output - carry messages frm CNS to muscles & glands
What does the SNS include?
Nerves that are connected to sensory receptors & skeletal cells
look at slide 13 of lecture 2 (week 8) - the brain and the mind - part 1 for an overview of the nervous system
HAVE YOU LOOKED AT IT????????
What are the building blocks of the NS?
Neurons/nerves cells
Glia cells
What do neurons/nerve cells do?
Communicate - transmit info to, frm & within the CNS
What do glia cells do?
Hold neurons tgt
Nourish, insulate & protect neurons
Baasically - physical & metabolic support of NS
NO communication at all
What are the parts of a neuron?
- Dendrites
- Soma
- Axon
- Axon terminals
- Myelin sheath
What are dendrites?
Branch-like structures that receive info frm other neurons & transmit it to cell body
What is the soma?
Cell body –> keeps cell alive & determines whether it will fire (based on accumulated inputs frm dendrites)
What is the axon?
tube-like extension that transmits messages to other neurons, muscles, gland cells
What are the axon terminals?
terminal branches of an axon
basically, end of axon
What is the myelin sheath?
Fatty insulation surrounding the axon (outer covering)
Helps to speed the neural impulses
How many pairs of peripheral nerves are there in a human body?
43 pairs
12 pairs are in the head
What the ways that neurons communicate?
- Electrical process
- Chemical process
- Cleaning up process
What is the electrical process of communication (done by neurons)?
Communication within a neuron
Action potential –> neural impulse & brief electrical charge that travels down an axon (created by depolarising current)
Info pushed through axon based on +ve & -ve charges of ions
What is the chemical process of communication (done by neurons)?
Communication b/w neurons
Neurotransmitter –> chemical substance released by transmitting neuron at synapse –> alters activity of receiving neuron
(binds to receptor on surface of receiving neuron)
What is the cleaning up process (neuron communication)?
Reuptake
Reabsorb excess neurotransmitters by the sending neuron
What are the functions of dopamine (neurotransmitter)?
Influences movement, learning, attention, sensations of pleasure
Dopamine (DA)
What are the functions of serotonin (neurotransmitter)?
Affects mood, appetite, sleep, anxiety
Serotonin (5-HT)
What are the functions of Acetylcholine (neurotransmitter)?
Enables muscle action, learning, memory
Acetylcholine (ACh)
What are the functions of Norepinephrine (neurotransmitter)?
Helps control alertness & arousal
Norepinephrine (NE)
What are the functions of Gaba-amino butyric (neurotransmitter)?
Involved in sleep & inhibits movement
Gaba-amino butyric (GABA)
What are the functions of endorphins (neurotransmitter)?
Involved in pain relief
What are the malfunctions of dopamine (DA)?
- Oversupply
- Undersupply
- Oversupply: schizophrenia
- Undersupply: Parkinson’s dz, depression
What are the malfunctions of serotonin (5-HT)?
- Undersupply
- Undersupply: depression, sleep & eating disorders
What are the malfunctions of Acetylcholine (ACh)?
- Oversupply
- Undersupply
- Oversupply: muscle contraction, convulsions
- Undersupply: Alzheimer’s dz
What are the malfunctions of Norepinephrine (NE)?
- Oversupply
- Undersupply
- Oversupply: stress & panic disorder
- Undersupply: depression
What are the malfunctions of Gaba-amino butyric (GABA)?
- Undersupply
- Undersupply: seizures, tremors, insomnia
What are the malfunctions of Endorphins?
- Oversupply
- Undersupply
- Oversupply: insensitivity to pain
- Undersupply: pain hypersensitivity, immune problems
How does cocaine affect neurotransmitters?
Blocks reuptake of dopamine –> allows dopamine to stay active longer
Dopamine stays in the synaptic gap for longer & cont. to bind to receptors = enhanced dopamine neurotransmission
List 6 neurotransmitters
- Dopamine (DA)
- Serotonin (5-HT)
- Acetylcholine (ACh)
- Norepinephrine (NE)
- Gaba-amino butyric (GABA)
- Endorphins
What is the endocrine system (ES) known as?
2nd communication system interconnected with the NS
What are the 2nd class chemical messengers?
Hormones
secreted by endocrine glands
What is long distance messenging?
Hormones travel thru bldstream to organs & cells far from point of origin
Endocrine system vs Nervous system
Both produce chemicals that act on receptors elsewhere
NS occurs in fraction of a second
ES takes several seconds
List the endocrine glands (6 points)
- Pituitary gland
- Pineal gland
- Thyroid gland
- Pancreas
- Gonads
- Adrenal glands
Where is the pituitary gland located and what does it secrete?
Brain
Secretes human growth hormone
Where is the pineal gland located and what does it secrete?
base of cerebrum
Secretes melatonin (biological rhythms & sleep)
Where is the thyroid gland located and what does it secrete?
neck
Secretes thyroxin (growth & metabolism)
Where are the adrenal glands located and what does it secrete?
top of each kidney
Secretes over 30 hormones (corticoids/steroids) –> control stress reactions
Where is the gonads located and what does it secrete?
Ovaries & testes
regulate sexual behaviour & reproduction
Where is the pancreas located and what does it secrete?
under the liver
secretes insulin & glucagon
What does lesioning studies examine?
Examines brain areas that are damaged in animals & people
Electrical current destroys target neurons (using electrodes)
What is brain stimulation?
electrical stimulation to disrupt/enhance brain areas –> study changes in behaviour & cognition
Deep brain stimulation (DBS)
Transcranial magnetic Stimulation (TMS)
What does deep brain stimulation (DBS) do?
Stimulates brain from the inside (INVASIVE)
treatment for Parkinson’s dz, seizures, chronic pain
What does transcranial magnetic stimulation (TMS) do?
stimulates brain from the outside w magnetic impulses (NON-INVASIVE)
used for PTSD, depression
What can be used to map the structure of the brain?
- Computed tomography (CT): use Xray to map brain slices (tumours/stroke damage)
- Magnetic resonance imaging (MRI): use magnetic fields & radio receivers for detailed & 3D images
What can be used to map the function of the brain?
- Electroencephalogram (EEG)
- Positron Emission Tomography (PET)
- Functional MRI (fMRI)
What is an Electroencephalogram (EEG)?
amplified recording of waves of electrical activity sweeping across the brain’s surface
measured by electrodes placed on scalp
What is Positron Emission Tomography (PET)?
visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a task
radioactive form of glucose = tracer
What is Functional MRI (fMRI)?
tracking changes in the blood oxygen levels
inc. levels = inc. functioning
used to study activity linked w specific thoughts & behaviour
MRI vs fMRI
MRI: shows anatomy
fMRI: shows change in blood flow related to brain activity
Both use magnetic fields to create images
fMRI vs PET
fMRI:
- clearer image
- can be repeated many times bc no radiation exposure
- widely available
- affordable
PET:
- better signal-to-noise ratio (basically vv clear)
fMRI –> increasing use now compared to PET
The brain is divided into 3 parts:
- hindbrain - functions essential to maintain life
- midbrain - impt for sensory & motor functions
- forebrain - higher functioning (thinking, decision-making)
What does the hindbrain comprise of?
Medulla
Pons
Cerebellum
What does the medulla do?
controls heartbeat, breathing, digestion
What does the pons do?
influences sleep, waking, dreaming, motor control
What is the reticular formation in the hindbrain?
nerve network that runs from hindbrain through midbrain to forebrain
controls arousal & attention (consciousness)
What does the cerebellum do?
aka little brain
regulates movement & balance
involved in some cognitive functions (e..g receives messages frm muscle, tendons, structures, etc)
What does the forebrain comprise of?
Limbic system
Cerebrum
What is the limbic system for?
emotions, motivations, memory, learning