Unit 2: Biological Bases of Behavior Flashcards
Why are psychologists concerned with human biology?
Everything physiological is simultaneously biological
Who is Franz Gall? What did he study?
German physician who studied phrenology - the study of bumps on the skill to reveal brain size and subsequent mental abilities and character traits
Neurons
a nerve cell: basic building block of the nervous system - act as an information system in the body (we have billions)
Dendrites
A neurons often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body
Axons
The neuron extension that passes messages through its branches to other neurons or to muscles/glands
Myelin sheath
A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed
- insulates and speeds their impulses, increasing neural efficiency
- when it deteriorates we can develop multiple sclerosis: communication to muscles slows, with eventual loss of muscle control
Cell body
the part of a neuron that contains the nucleus; the cell’s life support center
Terminal branches of the axon
forms junctions with other cells
Glial cells
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory
Action potential
(exchange of ions)
- Resting potential: when the axon’s surface is selectively permeable, maintaining a positive charge outside the axon, and a negative charge inside it
- Depolarization: the axon opens it’s gates and positively charged sodium ions flood through the now-open channels to produce a loss of the inside/outside charge difference; this initiates the opening of the nest set of axon channels to open (like dominos)
- Refractory period: neurons need short breaks; subsequent action potentials cannot occur until the axon returns to its resting state
All-or-none response
- a neuron’s reaction of either firing with a full-strength response or not firing at all
like a toilet flush, it needs a certain threshold to trigger
Excitatory vs. inhibitory signals
excitatory signals are like pushing a neuron’s gas pedal, and inhibitory signals are like pushing it’s break
Synapse
the junction between the axon top of the sending neuron and the dendrite or cell body of the receiving neuron - the tiny gap at the junction is called the synaptic gap
Reuptake
- the reabsorption of a neurotransmitter by the sending neuron
- they do this to remove excess neurotransmitters for reuse, and to prevent the job from continuing
Neurotransmitters
chemical messengers that cross the synaptic gap between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
Neurotransmitters and their functions/malfunctions
ACh (Acetylcholine)
- enables muscle action, learning, and memory
- with Alzheimer’s disease, ACh-producing neurons deteriorate
Dopamine
- influences movement, learning, attention, and emotion
- oversupply linked to schizophrenia, undersupply linked to tremors and decreased mobility in Parkinsons disease
Serotonin
- affects mood, hunger, sleep, and arousal
- undersupply linked to depression
Norepinephrine
- helps control alertness and arousal
- undersupply can depress mood
GABA
- a major inhibitory neurotransmitter
- undersupply liked to seizures, tremors, and insomnia
Glutamate
- a major excitatory neurotransmitter, involved in memory
- oversupply can over-stimulate brain, producing migraines or seizures
Endorphins
- influence the perception of pain or pleasure
- oversupply with opiate drugs can suppress the body’s natural endorphin supply
Agonists vs antagonists
Agonists - a molecule that increases a neurotransmitter’s action
Antagonist - a molecule that inhibits or blocks a neurotransmitter’s action
Nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands and sense organs
Types of neurons
Sensory/afferent neurons - neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord
Interneurons - neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs
Motor/efferent neurons - neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
Peripheral Nervous System
sensory and motor neurons that connect the CNS to the body; a combination of the somatic nervous system and the autonomic nervous system
somatic - the division of the peripheral nervous system that controls the body’s skeletal muscles
autonomic - the part of the peripheral nervous system that controls the glands and the muscles of the internal organs
Divisions of the PNS
Sympathetic nervous system - arouses and expends energy (fight or flight)
Parasympathetic nervous system - conserving energy/calming(rest and digest)
^ these work together to maintain homeostasis
** you hear a weird sound in the night and your sympathetic nervous system kicks in, but when you realize it’s just your dog, your parasympathetic calms you down
Central Nervous System
two-way information highway: connects the peripheral nervous system and the brain
Simple reflex
a simple, automatic response to a sensory stimulus - no time for a middle step to/from the brain before the action takes place
** when you touch something hot, your hand jerks away before your brain registers you are in pain
Endocrine system
chemical communication system; glands that secrete hormones into the bloodstream
Hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissue
Hormones vs. neurotransmitters
- chemically identical
- hormones are slow acting, neurotransmitters are fast
- hormones are long-lasting, neurotransmitters are short-lived
- hormones are produced in glands, neurotransmitters come from the brain
Adrenal glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress
Pituitary gland
The endocrine system’s most influential gland. under the influence of the hypothalamus, the pituitary gland regulates growth and controls other endocrine glands
Lesion
tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue
Electroencephalogram (EEG)
an amplified recording of the waves of electrical activity sweeping across the brain’s surface, measured by electrodes placed on the scalp
Magnetoencephalogram (MEG)
a brain imaging technique that measures magnetic fields from the brains natural electrical activity
Computed tomography
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure
PET scan
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain is performing a task