biopsychology- the nervous system and the endocrine system Flashcards
nervous system definition
consists of the central nervous system and the peripheral nervous system. communicates using electrical signals
central nervous system (CNS) definition
consists of the brain and the spinal cord and is the origin of all complex commands and decisions
peripheral nervous system (PNS) definition
sends information to the CNS from the outside world, and transmits messages from the CNS to the muscles and glands in the body
somatic nervous system (SNS) definition
transmits information from receptor cells in the sense organs to the CNS. it also receives information from the CNS that directs muscles to act
autonomic nervous system (ANS) definition
transmits information to and from the internal bodily organs. it ‘autonomic’ as the system operates involuntarily. it has 2 main divisions, the sympathetic nervous system and the parasympathetic nervous system
what is the nervous system
specilised network of cells in the human body and is our primary internal communication system. it is based on electrical and chemical signals
2 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 2 subsystems is the nervous system divided into
-central nervous system
-peripheral nervous system
what is central nervous system made up of
brain and spinal cord
brain
-center of all conscious awareness. the brains outer layer, the cerebral cortex is only 3mm thick (only found in mammals)
-the brain is highly developed in humans and is what distinguishes our mental functions from those of other animals
-divided into 2 hemispheres
spinal cord
-extension of the brain. passes messages to and from the brain and connects nerves to the PNS. it is also responsible for reflex actions such as pulling your hand away from a hot plate
what is the peripheral nervous system subdivided into
-autonomic nervous system
-somatic nervous sytem
peripheral nervous system
transmits messages, via millions of neurons, to and from the central nervous system
autonomic nervous system (PNS)
governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
somatic nervous system
governs muscle movement and receives information from sensory receptors
is nervous system or endocrine system faster
nervous system
nervous system average response time
0.25secs but may be as fast as 100milliseconds
endocrine average response time
2/3secs
why is endocrines response longer
as hormones travel through the bloodstream
does response last longer for endocrine or nervous system
endocrine
what do the endocrine and nervous systems work together to do
control vital functions in the body
endocrine system speed and effects
acts more slowly than the nervous system by has widespread and powerful effects
how does endocrine system work
various glands in the body (such as thyroid gland) produce hormones. hormones are then secreted into the bloodstream and effect any cell that has the receptor for that particular hormone
effect of hormones
most hormones effect cells in more than one body organ, leading to many diverse and powerful responses. for example, thyroxine affects cells in heart as increases heart rate, it also affects cells throughout the body increasing metabolic rates which affects growth rates
main glands in endocrine system
-pituitary gland in the brain, known as the master gland as it controls the release of hormones from all other endocrine glands in the body
-hypothalamus
-thyroid
-parathyroid
-adrenals
-pancreas
-ovaries (female)
-testes (male)
endocrine system definition
one of the body’s major information systems that instructs glands to release hormones directly into the bloodstream. these hormones are carried towards target organs in the body. communicates via chemicals
gland definition
an organ in the body that synthesises substances such as hormones
hormones definition
chemical substances that circulate in the bloodstream and only affect target organs. they are produces in large quantities but disappear quickly. the effects are very powerful
fight or flight response definition
the way an animal responds when stressed. the body becomes physiologically aroused in readiness to fight an aggressor or, in some cases, flee
adrenaline definition
a hormone produces by the adrenal glands which is part of the human body’s immediate stress response system-stimulating heart rate, contracting blood vessels and dilating air passages
when is body in parasympathetic state
normal resting state
when is body in sympathetic state
when physiologically aroused
how do endocrine and autonomic nervous system (ANS) work together
in parallel with one another, for instance during a stressful event
what happens when a stressors is perceived
-hypothalamus (in the brain) activates pituitary gland which trigger activity in the sympathetic branch of the autonomic nervous system
-the ANS changes from its normal resting state (parasympathetic state) to physiologically aroused (sympathetic state)
adrenaline
the stress hormone adrenaline is released from the adrenal medulla (part of adrenal gland near kidneys) into the bloodstream. it triggers physiological changes in the body (such as increased heart rate) which creates physiological arousal needed for fight or flight
immediate and automatic
all this happens as soon as the threat is detected. this is an acute response and an automatic reaction in the body. there are physiological changes associated with this sympathetic response. these changes explain why stress, panic or excitement are often experienced as a sick feeling
parasympathetic action
once the threat has passed, the parasympathetic nervous system returns the body to its resting state. the parasympathetic branch of the ANS works in opposition to the sympathetic nervous system- its actions are antagonistic to the sympathetic system, the parasympathetic system acts as a ‘brake’ and reduced the activated of the body that were increased by the action of the sympathetic branch. this is sometimes referred to as the rest and digest response
biological changes associated with the sympathetic state
-increased heart rate
-increased breathing rate
-dilates pupils
-inhibits digestion
-inhibits saliva production
-contracts rectum
biological changes associated with the parasympathetic state
-decreases heart rate
-decreases breathing rate
-constricts pupils
-stimulates digestion
-stimulates saliva production
-relaxes rectum
