Chapter 3: Biological Foundations of Behaviour

Question 1

Neurons

Answer 1

3 main parts:
-Cell body / soma
-Dendrites
-Axon

Question 2

Cell body / soma

Answer 2

-contains stuff that keeps neutron alive
-contains genetic information for cell development and function

Question 3

Dendrites

Answer 3

-branch-like fibres
-collect messages from other neurone and sends them to the soma
-receiving end of the neuron

Question 4

Axon

Answer 4

-branches out to form an axon terminal
-conducts electrical impulses to other neurons, muscles, glands
-connects with dendritic branches to connect neurons

Question 5

Glial cells

Answer 5

-surround neurons
-holds them in place
-manaufacture nutrients
-absorbs toxins and waste
-blood-brain barrier prevents substances from entering the brain

Question 6

Nerve Conduction

Answer 6

-neurons are surrounded by salty liquid with Na+
-the inside of a neuron is more negative

Question 7

Action Potential

Answer 7

the sudden several in neuron’s membrane voltage

Question 8

Depolarization

Answer 8

-increases in mV from -70 to 40

Question 9

Graded Potentials

Answer 9

-changed proportional to the incoming stimulation
-ion channels: tiny protein structures that open to let more Na+ into the neuron and making it less negative
-then they close quickly, then K+ channels open to let them out and restores neuron to resting potential

Question 10

Refractory Period

Answer 10

-time where the membrane is not excitable and can’t discharge more action potential

Question 11

Myelin sheath

Answer 11

-fat insulation layer made of glial cells that covers axons
-it allows for high conduction speeds along the axon

Question 12

Synaptic Transmission

Answer 12

-Otto Leowi discovered that neurons release chemicals to pass to the next neuron
-there are synaptic clefts between axon terminals and dendrites
-neurotransmitters are produced and carry messages across a synapse to excite or inhibit other neurons
-occurs in five steps:
#1: synthesis
#2: storage
#3: release (caused by action potential, chemical molecule leave)
#4: binding (they bind to receptor sites)
-excitation: depolarization of the cell membrane by stimulating the flow of Na+ into the cell
-inhibition: stimulating ion channels to let K+ flow out, or lets -’ve ions flow in to make it more negative
#5: deactivation
-neurotransmitters continue to function until they are deactivated
-some are deactivated by chemicals that break them down
-Reuptake: they are reabsorbed into axon terminals

Question 13

Examples of Neurotransmitters

Answer 13

-Acetylcholine (inhibition of memory, motor, behaviour)
-Norepinephrine (arousal and eating)
-Dopamine (arousal and voluntary movement)
-Serotonin (sleep and thermoregulation)
-Gamma Aminobutyric Acid (motor behaviour)

Question 14

Drugs that affect Neurotransmitters

Answer 14

-some drugs increase or decrease neurotransmitter amounts, stimulates or blocks receptor sites, or blocks transmitter function
-Cocaine: stimulates release of dopamine
-Caffeine: blocks adenosine receptor sites

Question 15

The Nervous System

Answer 15

-3 major types of neurons
#1: sensory neurons (carry input messages from organs to the brain)
#2: motor neurons (transmits output messages from the brain to organs)
#3: interneurons (performs connective functions to link everything together)

Question 16

Peripheral Nervous System

Answer 16

-all neural structures that aren’t the brain or the spinal cord
-neurons travel along this to carry messages
-2 major divisions

Question 17

2 Major Divisions of the Peripheral Nervous System

Answer 17

1: somatic nervous system: sensory and motor neurons to control sensations and voluntary movements

#2: autonomic nervous system: controls glands, involuntary muscles, has 2 divisions
-sympathetic nervous system: activation and arousal functions (increased heart beat, dilated pupils)
-parasympatheic nervous system: slows down the body
-homeostasis: balanced state

Question 18

Central Nervous System

Answer 18

-the brain and spine
-the spine is protected by vertebrate, the brain is protected by the skull
-Neuropsychological Tests: measures behaviours to locate brain damage
-Destructive and Stimulation techniques: controlled damaging for research
-Electrical Recording: analyzing EEG graphs
-Brain Imaging: CT scans, PET scans, MRI

Question 19

Structure and Behavioural Functions of the Brain

Answer 19

1: Hindbrain

#2: Midbrain
#3: Forebrain
#4: Cerebral Cortex

Question 20

Hindbrain

Answer 20

1: brain stem:

-medulla controls heart rate and transpiration
-pons is a bridge that helps nerve impulses to travel
-two way stem, connects to the spinal cord
#cerebellum:
-look like a little brain attached to the brain stem
-timing of muscular movement coordination
-they are initiated in higher brain centres
-learning, memory

Question 21

Midbrain

Answer 21

-composed of clusters of sensory and motor neurons, as well as tracts to connect higher and lower portions of the nervous system
-Reticular Formation: acts as a sentry to alert higher centres of incoming signals, affects sleep, wakefulness, and attention

Question 22

Forebrain

Answer 22

-2 large cerebral hemispheres that wrap around the brain stem
-outer portion is covered by the cortex
-Thalamus: reroutes sensory inputs towards appropriate brain area
-Basal Ganglia: voluntary motor control
-Hypothalamus: sexual behaviour, temperature regulation, eating, etc.
-Limbic System: motivational and behavioural
-Hippocampus: forming and retrieving memories
-Amygdala: organizes emotional response

Question 23

Cerebral Cortex

Answer 23

-thick sheet of grey cells on the outermost layer of the brain
-four lobes: frontal, parietal, occipital, temporal
-Motor cortex: controls muscles
-Sensory cortex: sensations, balance
-Speech comprehension and production;
-Wernicke’s area: language comprehension
-Broca’s area: normal speech production
-Association cortex: found in all cerebral cortex lobes, highest mental functions
-Frontal lobes: includes Broca’s area, motor cortex, and an associative cortex
-also involved in emotional experience
-Prefrontal Cortex: directing behaviour and adapting

Question 24

Hemispheric Lateralization

Answer 24

-Corpus callosum is a neural bridge that acts as a communication link between the two hemispheres
-Lateralization: localization of a function in one of two hemispheres
-left: verbal abilities, speech, math, logic, positive emotions
-right: imagery, music, art, relationships, negative emotions
-if the corpus callosum is cut, visual input in one hemisphere will only project stimulus to one side of the visual field
-Split Brain Experimentations

Question 25

Brain Plasticity

Answer 25

-Neural plasticity: neurons can change in structure and function
-early experiences during brain development can alter brain areas
-greater amount of synapses in children allow for a greater change of recovery from damage
-adults can maintain and recover function when surviving neurons adapt and modify