Biopsychology - the nervous system and endocrine Flashcards
define nervous system
consists of the central nervous system and peripheral nervous system
- communicates using electrical signals
define central nervous system
consists of the brain and spinal chord and is the origin of all complex commands and decisions
define peripheral nervous system
sends information to the CNS from the outside world and transmits messages from the CNS to the muscle and glands in the body
define somatic nervous system
transmits information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act
define autonomic nervous system
transmits information to and from internal bodily organs. It is ‘autonomic’ as the system operates involuntarily.
it has two main divisions, the sympathetic and parasympathetic nervous systems
what is the nervous system?
a specialised network of cells in the human body and is our primary internal communication system
what is the nervous system based on?
on electrical and chemical signals
what is the endocrine system based on?
hormones
what are the two main functions of the nervous system?
-to collect, process and respond to information in the environment
- to co-ordinate the working of different organs and cells in the body
what are the two subsystems that the nervous system is divided into?
the Central nervous system and the peripheral nervous system
what is the CNS made up of?
the brain and the spinal chord
what is the brain?
the brain is the centre of all conscious awareness
how is the brain structured?
the brain’s outer layer , the cerebral cortex is 3mm thick and covers the brin like an orange peel
only found in mammals
what is the brain divided into?
two hemispheres
what is the spinal chord?
an extension to the brain - it passes messages to and from the brain and connects nerves to the PNS
its also responsible for reflex actions
what does the PNS do?
transmits messages via millions of neurons to and from the CNS.
what is the PNS further subdivided into?
Autonomic nervous system and Somatic nervous system
what does the Autonomic nervous system do?
governs vital functions in the body such as breathing, heart rate, digestion , sexual arousal and stress responses
what does the somatic nervous system do?
governs muscle movement and receives information form sensory receptors
how does the endocrine system act compared to the nervous system?
the endocrine system acts more slow than the nervous system but has widespread powerful effects
how do hormones work?
they are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone
The thyroid gland produces the hormone thyroxine - what does this do?
Affects cells in the heart and so increases heart rate - which in turn affects growth rates
Why is the pituitary gland called the ‘master gland’?
Because it controls the release of hormones from all the other endocrine glands in the body
How do the endocrine system and autonomic nervous system work?
Often in parallel with one another
What happens when a stressor is perceived?
Part of the brain called the hypothalamus activates the pituitary gland which triggers activity in the sympathetic branch of the autonomic nervous system
When a stressor is perceived , what happens to the ANS?
It changes from the normal resting state (parasympathetic state) to the physiologically aroused sympathetic state
What gland is adrenaline from?
The adrenal medulla
What does adrenaline trigger?
Physiological changes in the body (such as increased heart rate) which creates the physiological arousal necessary for the fight / flight response
What is immediate and automatic?
Starts happening in an instant - as soon as threat is detected , this is an acute response and an automatic reaction in the body.
What are some sympathetic responses?
Stress, panic, excitement
What does the parasympathetic nervous system do?
Once the threat has passed, it returns the body to its resting state
How do the sympathetic and the parasympathetic branch of the ANS work together?
The parasympathetic branch of the ANS work in opposition to the sympathies nervous system
The parasympathetic system acts as a brake and reduces activities of the body that were increased by the actions of the sympathetic branch
Sometimes referred to as ‘rest and digest’
Define endocrine system
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream - these hormones are carried toward target organs in the body
Define gland
Organ in the body that synthesises substances such as hormones
Define hormone
Chemical substance that circulates in the bloodstream and only affects target organs
Effects are very powerful
Define fight /flight response
The body becomes physiologically aroused in readiness to fight an aggressor or flee
Give examples of how the sympathetic state is the opposite to the parasympathetic state?
SS - increases heart rate
PS- decreases heart rate
SS- dialates pupils
PS- constricts pupils
SS- contracts rectum
PS- relaxes rectum
