Chapter 3 Biology Flashcards
Neuroanatomy
Study of parts and functions of neurons
Neuroscience/bio psychological perspective
Influence of biology on psychology
- genetics
- functioning of brain and nervous system
Neuron parts
- dendrites
- cells body or soma
- axon
- myelin sheath
- terminal buttons
- neurotransmitters
- synapse
Neurons
Individual nerve cells
Dendrites
Rootlike parts of neurons that stretch out from cell body to make synaptic connections with other neurons
Cell body/soma
Nucleus and other centeral parts of neuron cell to sustain life
Axon
Wirelike structures extending from cell body and ending in terminal buttons
Myelin sheath
Fatty covering around the axons of some neurons that speeds neural impulses
Terminal buttons
Branched end of the axon of neuron that has neurotransmitters
Neurotransmitters
Chemicals in terminal buttons of neuron that enable neurons to communicate, fit into receptor sites of other neuron’s dendrites
- excitatory- excite next cell into firing
- inhibitory - inhibit next cell from firing
Synapse
Space bw terminal buttons of one neuron and the dendrites of next neuron
How a neuron fires
Neuron firing from A to B to C
- terminal buttons of neuron A stimulated
- release nuerotransmitters into synapse
- if threshold level of nuerotransmitters are received by neuron B dendrite receptors, cell membrane becomes permeable and action potential occurs
- action potential stimulates terminal buttons of B, process begins again if threshold level is reached in neuron C
- all or none principle
Threshold
Level of neurotransmitters needed to be received by dendrite receptors for action potential to take place
Neuron in resting state
- negatively charged, b mostly neg ions in neuron and mostly positive ions surrounding it
- selectively permeable to prevent ions from mixing
Action potential
When a threshold or greater amount of neurotransmitters have been received by receptors, neuron becomes permeable and positive ions rush into the cell. The change in charge spreads thruout neuron from neg to pos
-May or May not send message, just has ability to
All or none principle
How a neuron fires completely or does not fire at all, a neuron cannot fire a little or a lot. Impulse same every time
Nervous system
How we bring info from our senses to our brain
2 types
- central nervous system
- peripheral nervous system
Types of neurons
since neurons only fire in one direction, we need 2 sets of neuron trails, one to take info from brain to muscles, other from senses to brain
- afferent neurons
- internuerons
- efferent neurons
Afferent neurons
Take info from senses to the brain
Interneurons
Takes messages that reach the brain or spinal cord and sends them elsewhere in the brain or onto efferent neurons
Efferent neurons
Take info from brain to the rest of the body
Central nervous system
Brain and spinal cord (all the nerves encased in bones)
spinal cord-
bundle of nerves than run thru center of spine, transmits info from rest of body to brain
Peripheral nervous system
- nerves not encase in bone
- somatic nervous system
- automatic nervous system
Somatic nervous system
Controls our voluntary muscle movements
- motor cortex of the brain sends impulses to somatic system
Automatic nervous system
- controls automatic functions in body
Like heart lungs glands etc - responses to stress (fight or flight)
2 types
- sympathetic
- parasympathetic
Sympathetic nervous system
- mobilizes body to respond to stress, part of automatic nervous system (alert system)
- accelerates heart rate blood pressure respiration; slows down digestion
Parasympathetic nervous system
Responsible for slowing down body after a stress response
Reflexes
Reactions that occur the moment sensory impulses reach the spinal cord (some are adaptive like when you touch something really hot or cold)!
Ways of studying the brain
- accidents
- lesions
- electroencephalogram
- computerized axial topography
- magnetic resonance imaging
- positron emission topography
- functional MRI
Studying brain thru accidents
when people have an accident and damage a piece of their brain, researchers see how thoughts and behavior are affected
Lesions in brain study
when someone’s brain tissue is surgically removed b they have a tumor or something, researchers see how thought and behavior are affected
electroencephalogram
EEG detects brain waves, used in sleep research
- to study brain
Computerized axial topography
CAT scan uses several x ray cameras to create a 3d pic of brain structure
- tool to study brain
Magnetic resonance imaging
- MRI
- like the CAT scan in that it can only give doctors an image of brain structure but it is a lot more detailed layout, uses magnetic fields instead of x rays
Positron emission topography
Lets researches see what are as of the brain are most active during certain tasks
- diff scans for diff chemicals
Functional MRI
- fMRI, new tech
- combines elements of MRI and PET scans to show 3d brain structure and what areas of the brain are very active
Brain parts
Hindbrain, midbrain, forebrain, cerebral cortex
Hind brain parts
- medulla
- pons
- cerebellum
Hindbrain
- structures in top part of spinal cord
- basic biological functions
Medulla
- controls blood pressure, heart rate and breathing
- above spinal cord
Pons
- connects hindbrain with midbrain and forebrain
- controls facial expressions, sleep and arousal
- above medulla and towards front
Cerebellum
- bottom rear of the brain
- means little brain b it looks like one
- coordinates habitual muscle movements
Midbrain
- bw forebrain and hindbrain
- Coordinates simple movements in response to sensory stimulation
- reticular formation- controls general body arousal and ability to focus attention, if it doesn’t work we fall into a deep coma
Forebrain
- Frontal part of brain
- controls complex thought and reason
- large size of forebrain sets humans apart from other species
Forebrain parts
- thalamus
- hypothalamus
- amygdala
- hippocampus
Thalamus
- Top of the brain stem
- gets sensory signals from spinal cord and sends them to appropriate areas in the rest of the cerebrum
Hypothalamus
- small structure next to thalamus
- controls 4 fs: fighting fleeing feeding and fornification(sex)
- controls endocrine system
Amygdala
- near the end of each hippocampal arm
- used to experience emotion, especially in learning fear responses
Hippocampus
- Encodes and processes memories before being being sent to other areas in the cerebral cortex for permanent storage
- 2 arms surrounding the thalamus
Important Neurotransmitters
- acetylcholine
- dopamine
- endorphins
- serotonin
- GABA
- glutamate
- norepinephrine
- epinephrine
Acetylcholine
- Voluntary moving, learning, memory
- too much- depression
- lack associated with Alzheimer’s and dementia
Dopamine
- mood attention movement
- lack associated with Parkinson’s
- And too much associated with schizophrenia
Endorphins
- Neurotransmitter used as pain relief and pleasure
Serotonin
- mood, sleep, aggression
- lack associated with depression and OCD
- too much- heart problems
GABA
- important inhibitory neurotransmitters
- too much- overly sedated
- too little- anxiety and seizures
Glutamate
- Excitatory neurotransmitter involved in memory
- migraines and seizures
Norepinephrine
- alertness, eating, stress responses
- too much- schizophrenia
- too little- depression-
Cerebral cortex
- Gray thin surface of the brain made of neurons that grow and connect as we develop
- fissures enable it to hold more neurons with a larger surface area
- babies have more neurons than we do now
- made of 2 hemispheres
- each hemispheres has 4 diff lobes
Fissures
Wrinkles of the cerebral cortex that increase surface area to hold more neural connections
Cerebral cortex hemispheres
- Contralateral control
- no conclusions drawn yet on whether left is more active during logical tasks and right is more creative
- research being done of brain lateralization or hemispheric specialization by studying split brain patients
Contralateral control
- left brain hemisphere controls motor function of right side of body, right hemisphere controls the left
Brain lateralization
Specialization of function in each hemisphere of brain
Split brain patients
Ppl whose corpus callosum has been removed to treat severe epilepsy but are for brain lateralization
- operation pioneered by roger sperry and Michael gazzinga
Corpus callosum
Nerve bundle that connects 2 brain hemispheres
Cerebral cortex lobes
- 4 on each hemisphere
- frontal, parietal, temporal, and occipital
- also association areas
Association area
Any area of cerebral cortex not associated with receiving sensory info or controlling motor movements
- specific functions unknown, active in various thoughts and behaviors
Frontal lobes
- prefrontal cortex
- motor cortex
- Broca’s area
Prefrontal cortex
- very front of the frontal lobe
- directs critical abstract thought processes and emotional control
Broca’s area
Part of frontal lobe controlling muscles involved in speech
- named after Paul Broca
Motor cortex
- thin strip at the back of the frontal lobe
- controls voluntary muscle movements
- top of body controlled by bottom of motor cortex, bottom of body controlled by top of motor cortex
Parietal lobes
- Behind frontal lobe but still on top of head
- sensory cortex
Sensory cortex
Thin strip in parietal lobe behind motor cortex
- gets touch sensations from rest of body
- top gets sensations from bottom part of body and inverse true too
Occipital lobe
- lobe farthest back in brain
- visual cortex
Visual cortex
- part of occipital lobe
- impulses from retinas of eyes sent to visual cortex to be interpreted
- right visual field processed in left sides of each retina which is taken to the left cerebral hemisphere
Temporal lobe
- processes sound sensed by ears
- auditory cortex
- wernicke’s area
Auditory cortex
- Part of temporal lobe
- interprets neural impulses made by sound waves
- not lateralized, sound heard by left ear interpreted in both auditory cortices
Wernicke’s area
- interprets written words and spoken speech (language)
- in temporal lobe
- founded after Carl wernicke
Language areas of brain
- wernicke’s area
- Broca’s area
Brain plasticity
- how adaptable the brain is
parts of the brain made for certain functions might take over other jobs if the part of the brain usually performing these jobs is damaged - brain most plastic in younger children
Endocrine system
- system of glands that secrete hormones
- controlled in brain by hypothalamus
Some glands
- adrenal
- ovaries
- testes
Adrenal glands
- part of endocrine system
- secretes hormones of adrenaline putting body in fight or flight mode
Ovaries and testes
- gland part of the endocrine system
- secretes sex hormones: estrogen for female, testosterone for male
- explains gender differences
Nature vs nurture
Which contributes more to thought and behavior? Genetic code or the environment we grow up in?
Study identical twins (monozygotic) who have same genetic info
- Thomas bouchard’s study
Basic human genetics
- each cell- 46 chromosomes (23 pairs)
- chromosomes made of DNA
- DNA regulates protein production, these proteins control some traits
- segment of DNA that controls 1 protein is a gene
- genes can be expressed depending on if they are dominant or recessive
Thomas Bouchard
- did twin studies to examine nature vs nurture
- identical twins raised in different families still have a high correlation in scoring similar traits, however identical twins raised together are even more likely to have similar traits showing environ plays a role too
- criticism- effective psychological environ- even though twins are raised separately, they are treated similarly due to their identical appearance so in reality are exposed to same environ.
Chromosomal abnormalities
- turners syndrome
- klinefelters syndrome
- Down syndrome
Turners syndrome
Ppl born with only a single X chromosome
- shortness
- webbed necks
- diff in physical sexual development
Klinefelters syndrome
- have an extra X chromosome (xxy)
- causes minimal sexual development
- extreme introversion
Down syndrome
- extra chromosome on 21st pair
- rounder face
- shorter fingers and toes
- slanted far apart eyes
- degree of mental retardation
Glia
- supports, gives nutrients, and removes waste for efficient communication b/w neurons
- without glia, mood disorders and brain cancer
Pre synaptic neuron
Neuron that Sends message
Postsynaptic neuron
Neuron that Receives message
Synaptic vessels
Bubbles holding neurotransmitters in the terminal buttons , pops when releasing neurotrans into the synapse
Antagonist
Neurotransmitters that block receptor sites, because it doesn’t fit so it doesn’t let other neurotransmitters get in
Agonist
Mimics proper neurotransmitter to go into receptor site (fake chemical)
Excitatory neurotransmitter
Neurons that increase the likelihood that the next neuron will undergo action potential by promoting a plsitive voltage shift
Inhibitory neurotransmitters
Neurotransmitters that decrease likelihood next neuron will do action potential by promoting a negative voltage shift
Inhibitory post synaptic potential
Neuron receives mostly inhibitory neurotrans resulting in a negative voltage shift, decreases likelihood next neuron will go to action potential
Excitatory post synaptic potential
Neuron that receives mostly excitatory neurotransmitters resulting in a positive voltage shift, more likely to do action potential
Epinephrine
- associated with energy
- too much- anxiety restlessness
- too little- depression
Libido
Sexual arousal
Limbic system
hypothalamus amygdala and hippocampus
- deals with experience of emotion, memory, and pleasure
