The nervous system:
- Nervous system; consists of the central nervous system and the peripheral nervous
system. The primary internal communication system through electrical and chemical
signals (whereas endocrine is based on hormones). Has two main function:
(1) To collect, process and respond to information in the environment
(2) To coordinate the working of different organs and cells in the body
Divided into two subsystems:
(1) Central nervous system
(2) Peripheral nervous system
- Central nervous system; consists of the brain and spinal cord, the origin of all the
compex commands and decisions. The brain is the centre of all conscious
awareness, the cerebral cortex covers the brain and is found in mammals, our brain
distinguishes us from other animals due to higher mental functions. The spinal cord is
an extension of the brain which passes messages to and from the brain and
connects nerves to the peripheral nervous system, it is also responsible for reflex
actions.
- Peripheral nervous system; sends information from the receptor cells in the sense
organs to the central nervous system from the outside world, and transmits
messages from the central nervous system to muscles and glands in the body.
Transmits messages via millions of neurons. Subdivides into two systems:
(1) 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 system. Governs
vital functions such as breathing, heart rate, digestion, sexual arousal and
stress responses.
(2) Somatic nervous system; transmits information from receptor cells in the
sense organs to the central nervous system, and also receives information
from the central nervous system that directs muscles to act. Governs muscle
movement and receives information from sensory receptors.
The endocrine system:
- Endocrine system; 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, communication is via chemicals.
- Glands and hormones; a gland is an organ in the body that synthesizes substances
such as hormones. A hormone is a biochemical substance that circulates in the blood
but only affects target organs. They are produced in large quantities but disappear
quickly, although have a very powerful effect. For example the thyroid gland
produces thyroxine which is a hormone that affects cells in the heart (increases heart
rate) but also affects cells across the body such as increasing metabolic rates of
chemical processes in the cells. The master gland is in the brain and is called the
pituitary gland, it controls the release of hormones from all other endocrine glands.
- Endocrine and the autonomic nervous system working together; often during
stressful events in particular the endocrine system and the autonomic nervous
system work together - when a stressor is perceived the hypothalamus activates the
pituitary gland gland and this triggers activity in the sympathetic branch of the
nervous system. The autonomic nervous system changes from its normal resting
state (parasympathetic) to a physiologically aroused state (sympathetic).
, (1) The stress hormone adrenaline is released from the adrenal medulla (adrenal
gland) into the bloodstream, this causes physiological changes which create
arousal necessary for the fight or flight response)
(2) This happens as soon as the threat is detected. Changes can involve stress,
panic, excitement.
(3) Once the threat is passed the parasympathetic nervous system returns the
body to its resting state. The parasympathetic system acts as a brake and
reduces the activities of the body that were increased by the actions of the
sympathetic branch
- Fight or flight response; the way an animal responds when stressed. The body
becomes physiologically aroused in readiness to fight an aggressor.
- Adrenaline; a hormone produced by the adrenal glands which is part of the human
body’s immediate response to stress. Adrenaline has a strong effect on the cells of
the cardiovascular system that stimulate the heart rate, contract blood vessels and
dilating air passages.
Localisation of function:
- Localisation of function; the theory that different areas of the brain are responsible for
specific behaviours, processes or activities.
- Localisation versus holistic theory; before investigations of Broca and Wernicke
scientists generally supported the holistic view that all parts of the brain were
involved in the processing of thought and action.
- Hemispheres of the brain; the brain is divided into two halves called the left and right
hemisphere. Some functions are controlled or dominated by a particular hemisphere
(lateralisation). The general rule is that activity on the left side of the body is
controlled by the right hemisphere and vice versa.
- Lobes; the brain is divided into different lobes - the frontal, parietal, occipital and
temporal lobes.
- Motor area; (frontal lobe, both hemispheres) controls voluntary movement on the
opposite side of the body.
- Somatosensory area; (parietal lobes, both hemispheres) processes sensory
information from the skin
- Visual area; (occipital lobes, both hemispheres) receives and processes visual
information
- Auditory area; (temporal lobes, both hemispheres) analyses speech based
information
- Language centres of the brain;
1. Broca's area; (frontal lobe, left hemisphere) responsible for speech
production. Damage causes Broca's aphasia characterized by slow speech
lacking in fluency (eg. ‘Tan’)
2. Wernicke’s area; (temporal lobe, left hemisphere) responsible for language
comprehension and understanding. Damage causes Wernicke’s aphasia
characterized by nonsense strings of words.
- Evidence from neurosurgery; damage to areas of the brain has been linked to mental
disorders. Cingulotomy of neurosurgery involves isolating a region called the
cingulate gyrus which has been implicated in OCD. Dougherty found 44 people with
OCD who had undergone this procedure 30% were successful and 14% had a partial
response. This suggests mental disorders can be localised.
- Nervous system; consists of the central nervous system and the peripheral nervous
system. The primary internal communication system through electrical and chemical
signals (whereas endocrine is based on hormones). Has two main function:
(1) To collect, process and respond to information in the environment
(2) To coordinate the working of different organs and cells in the body
Divided into two subsystems:
(1) Central nervous system
(2) Peripheral nervous system
- Central nervous system; consists of the brain and spinal cord, the origin of all the
compex commands and decisions. The brain is the centre of all conscious
awareness, the cerebral cortex covers the brain and is found in mammals, our brain
distinguishes us from other animals due to higher mental functions. The spinal cord is
an extension of the brain which passes messages to and from the brain and
connects nerves to the peripheral nervous system, it is also responsible for reflex
actions.
- Peripheral nervous system; sends information from the receptor cells in the sense
organs to the central nervous system from the outside world, and transmits
messages from the central nervous system to muscles and glands in the body.
Transmits messages via millions of neurons. Subdivides into two systems:
(1) 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 system. Governs
vital functions such as breathing, heart rate, digestion, sexual arousal and
stress responses.
(2) Somatic nervous system; transmits information from receptor cells in the
sense organs to the central nervous system, and also receives information
from the central nervous system that directs muscles to act. Governs muscle
movement and receives information from sensory receptors.
The endocrine system:
- Endocrine system; 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, communication is via chemicals.
- Glands and hormones; a gland is an organ in the body that synthesizes substances
such as hormones. A hormone is a biochemical substance that circulates in the blood
but only affects target organs. They are produced in large quantities but disappear
quickly, although have a very powerful effect. For example the thyroid gland
produces thyroxine which is a hormone that affects cells in the heart (increases heart
rate) but also affects cells across the body such as increasing metabolic rates of
chemical processes in the cells. The master gland is in the brain and is called the
pituitary gland, it controls the release of hormones from all other endocrine glands.
- Endocrine and the autonomic nervous system working together; often during
stressful events in particular the endocrine system and the autonomic nervous
system work together - when a stressor is perceived the hypothalamus activates the
pituitary gland gland and this triggers activity in the sympathetic branch of the
nervous system. The autonomic nervous system changes from its normal resting
state (parasympathetic) to a physiologically aroused state (sympathetic).
, (1) The stress hormone adrenaline is released from the adrenal medulla (adrenal
gland) into the bloodstream, this causes physiological changes which create
arousal necessary for the fight or flight response)
(2) This happens as soon as the threat is detected. Changes can involve stress,
panic, excitement.
(3) Once the threat is passed the parasympathetic nervous system returns the
body to its resting state. The parasympathetic system acts as a brake and
reduces the activities of the body that were increased by the actions of the
sympathetic branch
- Fight or flight response; the way an animal responds when stressed. The body
becomes physiologically aroused in readiness to fight an aggressor.
- Adrenaline; a hormone produced by the adrenal glands which is part of the human
body’s immediate response to stress. Adrenaline has a strong effect on the cells of
the cardiovascular system that stimulate the heart rate, contract blood vessels and
dilating air passages.
Localisation of function:
- Localisation of function; the theory that different areas of the brain are responsible for
specific behaviours, processes or activities.
- Localisation versus holistic theory; before investigations of Broca and Wernicke
scientists generally supported the holistic view that all parts of the brain were
involved in the processing of thought and action.
- Hemispheres of the brain; the brain is divided into two halves called the left and right
hemisphere. Some functions are controlled or dominated by a particular hemisphere
(lateralisation). The general rule is that activity on the left side of the body is
controlled by the right hemisphere and vice versa.
- Lobes; the brain is divided into different lobes - the frontal, parietal, occipital and
temporal lobes.
- Motor area; (frontal lobe, both hemispheres) controls voluntary movement on the
opposite side of the body.
- Somatosensory area; (parietal lobes, both hemispheres) processes sensory
information from the skin
- Visual area; (occipital lobes, both hemispheres) receives and processes visual
information
- Auditory area; (temporal lobes, both hemispheres) analyses speech based
information
- Language centres of the brain;
1. Broca's area; (frontal lobe, left hemisphere) responsible for speech
production. Damage causes Broca's aphasia characterized by slow speech
lacking in fluency (eg. ‘Tan’)
2. Wernicke’s area; (temporal lobe, left hemisphere) responsible for language
comprehension and understanding. Damage causes Wernicke’s aphasia
characterized by nonsense strings of words.
- Evidence from neurosurgery; damage to areas of the brain has been linked to mental
disorders. Cingulotomy of neurosurgery involves isolating a region called the
cingulate gyrus which has been implicated in OCD. Dougherty found 44 people with
OCD who had undergone this procedure 30% were successful and 14% had a partial
response. This suggests mental disorders can be localised.
