biopsychology Flashcards
6 marker- with application
how did (X) through sensory, relay, motor neurons?
travels from sensory neurons to the brain, and through this information the impact would be felt. This is carried from PNS to central nervous system in the brain. Information is passed through relay neurons through the brain with the decision making of how to respond to the stimulus. (currently still mostly in CNS. this information is then varied from CNS to effectors (muscle in this case) by motor neurons and the reaction/ reflex is presented
what are circadian rhythms?
biological rhythms subject to a 24 hour cycle which regulate a number of body processes such as sleep-wake cycles and changes in core temperature
what are infradian rhythms?
cycle of- more than 24 hours e.g. monthly, seasonally e.g. menstrual cycle, hybernation
what are ultradian cycles?
multiple times in 24 hours: blood circulation, sleep cycle (90 mins), blinking, respiration
what are exogenous zeitgebers?
external factors in the environment that affect of entrain our biological rhythms such as influence of light on the sleep/wake cycle.
what are endogenous pacemakers?
internal body clocks that regulate many of our biological rhythms such as influence of the suprachaismaric nucleus on the sleep/ wake cycle
suprachiasmatic nucleus
tiny bundle of nerves located in the hypothalamus in each hemisphere or the brain. One of the primary endogenous pacemakers in mammalian species. Influential in maintaining circadian rhythms much as sleep/wake cycle. It lies above the optic chiasm (where nerve fibers are connected to the eye). Receives information about light directly from this
Siffres cave study
Michal Siffre spend extended periods in a cave with no light to observe whether his cycles (e.g. sleep/wake cycle) changed, through brain wave activity and tasks.
other studies on circadian rhythms
Aschoff and Wever convinced a forum of participants to stay in a dark underground bunker for 4 weeks. all but one of the participants s/w cycle extended to 29 hours. Circadian cycle was between 24 to 25 hours. Both this and Siffres study suggest natural s/w cycle might be longer that 24 hours but exogenous factors associated with our 24 hour day entrained this.
Study on cave with clock that went faster opposes this as even though there was no light they couldn’t fit to the changing sleep schedule that went from 24 hours to 22
what is the nervous system?
our primary internal communication system.
consists of the central nervous system (CNS) and the peripheral nervous system. It communicates using electrical signals.
two main functions of the nervous system
-collect, process and respond to information in the environment
-to co-ordinate the working of different organs and cells in the body
what subsystems is the nervous system divided into?
central nervous system
peripheral nervous system
what is the central nervous system?
consists of brain (center of all consciousness and awareness) and spinal chord (extension of the brain, passes messages to and from brain and connects nerves to PNS, responsible for reflex actions) and is the origin of complex commands and decisions
what is the peripheral nervous system?
sends information from the CNS from the outside world, and transmits messages from to muscles and glands in the body. subdivided into autonomic nervous system and somatic nervous system
what is the autonomic nervous system?
governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
what is the somatic nervous system?
governs muscle movement and receives info from the sensory receptors
what are subdivisions of the autonomic nervous system?
sympathetic nervous system and parasympathetic nervous system
what is the sympathetic nervous system?
a network of nerves that helps your body activate its “fight-or-flight” response.
what is the parasympathetic nervous system?
a network of nerves that relaxes your body after periods of stress or danger
what is the endocrine system?
one of the bodies major information systems that instructs glands to release hormones directly into the bloodstream. these hormones are carried towards target organs in the bodies. Communicates via chemicals, and works along side the nervous system.
which one is faster- the nervous system or endocrine system?
nervous system- electrical signals
what does thyroxine do?
from thyroid gland- increases heart rate and metabolic rates (increasing growth rates)
what is the fight or flight response ?
the way an animal responds when stressed. Body becomes physiologically aroused in readiness to fight an aggressor, or in some cases, flee.
Fight or flight process explanation
endocrine system and ANS work together. when a stressor is perceived, for example you have upcoming exams) the hypothalamus activates the pituitary gland and this triggers activity in the sympathetic branch of the ANS. The ANS changes from urs normal resting state (parasympathetic state) to the physiologically aroused state (sympathetic state). Adrenaline is released from adrenal medulla which creates the physiological arousal needed. Examples of responses immediately would be increased heart rate and inhibited digestion. Once the threat has the passed, the parasympathetic branch of ANS works in opposition of the SB, acts as a break and reduces activities in the body that were originally increased such as HR.
what are neurons?
nerve cells that process and transmit messages through electrical and chemical signals. There are 100 billion in our body, 80% of them being in our brain.
whats a sensory neuron?
carry messages from the PNS to the CNS. They have long dendrites and short axons
whats a relay neuron?
Connect the sensory neurons to the motor or other relay neurons. Short dendrites and long axons
whats a motor neuron?
connect the CNS to the effectors such as muscles or glands. Long axons and short dendrites.
structure of a neuron
-vary in size from millimeter to meter.
-cell body includes a nucleus, which contains genetic material of the cell.
-dendrites protrude from the cell body.
-Axon carries the impulse away from the cell body and is covered in a fatty layer of myelin sheath that protects the axon and speeds the electrical transmission.
-nodes of ranvier (gaps in the myelin sheath) are there because if the myelin sheath was continuous it would only slow down the impulse. Forcing the impulse to jump across speeds it up.
-terminal buttons at the end of the axon communicate with the next neuron in the chain across a gap called the synapse.
Where are neurons located?
the cell bodies of motor neurons may be in the CNS but they also have long axons that form part of the PNS. PNS clusters called ganglia hold sensory neurons. Relay neurons make up 97% of the neurons and are found in the brain and visual system.
Electrical transmission- firing of a neuron
while a neuron is in its resting state it is negatively charged compared to the outside. When a neuron is activated by the stimulus, the inside of the cell becomes positively charged for a split second causing action potential to occur. Creates an electrical impulse that travels down the axon to the end of the neuron.
hat is synaptic transmission?
process by which neighboring neurons communicate with each other by sending messages across the synapse (gap) that separates them.
What occurs during chemical transmission between synapses?
neurons communicate with each other in neural networks. Each neuron is separated by a synapse. Signals within neurons are transmitted electrically, however they are transmitted chemically between each other. When the electrical impulse reaches the end of a neuron (pre-synaptic terminal) it triggers the release of a neurotransmitter from tiny sacs called synaptic vesicles.
what is a neurotransmitter?
brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. They can be broadly divided into those that perform an excitatory function and inhibitory function
Why can direction of travel only be one way for neurotransmitters?
hey are released by a pre synaptic neuron terminal and received by a post synaptic receptor site.
What is excitation?
when a neurotransmitter (e.g. adrenaline) increases the positive charge of the post synaptic neuron. This increases the likelihood that the post synaptic neuron will pass on the electrical impulse. (fire)
What is inhibition?
when a neurotransmitter (e.g. serotonin) increases the negative charge of the post synaptic neuron. This decreases the likelihood that the PSN will pass on the electrical impulse. (fire)
Summation
Decision to fire is based on the summation. Action potential of the PSN is only triggered if the sum of the excitatory and inhibitory signals a any one time reach the threshold. E.g. PSN is inhibitory it is less likely to fire
Explain the process of synaptic transmission:
1)electrical impulse reaches the end of the neuron (axon)- (pre-synaptic terminal)
2)triggers release of neurotransmitters from synaptic vesicles
3)diffuses across the synapse to the post synaptic receptor sites on the dendrites of the next neuron.
what is localisation of function?
the theory that different areas of the brain are responsible for specific behaviors and processes. For example, the motor area being located in the back of the frontal lobe