biopsychology

the nervous system

-specialised network of cells in the human body that is our primary internal communication system

-based in electrical and chemical signals (differs from the endocrine system as that is based off hormones)

the neerous system’s two main functions and its two subsystems:

-to collect, process and respond to information in the environment

-to co-ordinate the working of different organs and cells in the body

its made up of two subsections:

-the central nervous system (CNS)

-the peripheral nervous system (PNS)

the central nervous system

-made of the brain and spinal chord

-brain is the center of all conscious awareness; its outer layer (the cerebral cortex) is 3mm thick and covers the circumference of the brain. the brain is highly developed in humans and is what distinguished our higher mental functions from those of other animals. it is divided into two hemispheres.

-the spinal cord is an extension of the brain (the brain stem). it passes messages to and from the brain and connects nerves to the PNS. its responsible for reflex actions (eg pulling ur hand away from a hot plate)

the peripheral nervous system

-transmits messages (via millions of neurons (nerve cells)) to and from the CNS. the PNS is further subdivided into the:

• automatic nervous system (ANS), which governs vital functions in the body (like breathing, heart rate, digestion, sexual arousal and stress responses)

• somatic nervous system (SNS), which govern muscle movements and retrieves information from sensory receptors

the endocrine system

-works alongside the nervous system to control vital functions in the body. the endocrine system acts more slowly than the nervous system but has widespread, diverse and powerful effects. 

-a gland is an organ in the body that synthesises substances such as hormones. hormones are biochemical substances that circulate in the blood but only affect target organs (organs with receptors to that particular hormone) - they’re produced in large quantities but disappear quickly although they’re effects are powerful (e.g. thyroid gland produces thyroxine affects heart cells (increases heart rate) and body cells that increase metabolic rates (chemical processes taking place in the cells, which in turn affects growth rates)). 

-the pituitary gland (in the brain) is often referred to as the ‘master gland’ because it controls the release of hormones from all other endocrine glands in the body

endocrine and ANS

-the endocrine system and the ANS work in parallel, for instance, during a stressful event. when a stressor is perceived (ur friend jumps up to frighten u), the hypothalamus instantly activates the pituitary gland, which triggers activity in the sympathetic branch of the automatic nervous system. the ANS changes from its normal resting state (the parasympathetic nervous system) to the physiologically aroused sympathetic state.

the endocrine system and ANS

fight or flight 

-adrenaline is released from the adrenal medulla (part of the adrenal gland) into the bloodstream and triggers physiological changes in the body (eg increased heart rate) which creates the psychological arousal necessary for fight or flight

-this is an acute and automatic response/ reaction in the body. the physiological changes associated with the sympathetic response is increased heart and breathing rate, dilated pupils, inhibited digestion and saliva production, and contracts rectum

parasympathetic action: once the threat has passed, the parasympathetic nervous system returns the body to its resting state (exact opposite of above symptoms (constricts, stimulates, relaxes), by reducing the activities of the body that were induced by the actions of the sympathetic branch (usually seen as the rest and digest response). the two subsystems are antagonistic to each other.

neurons and synaptic transmission

the structure and functions of neurons

the structure of neuron

-the cell body (soma) includes a nucleus, containing genetic information of the cell

localisation of function of the brain

ways of studying the brain: the purpose and the types

-the purpose of scanning in psychological research is often to investigate localisation

types:

• functional magnetic resonance imaging (fMRI)

• electroencephalogram (EEG)

• event-related potential (ERP)

• post-mortem examinations

functional magnetic resonance imaging (fMRI)

-works by detecting changes in blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain: when a brain area is more active, it consumes more oxygen and to meet this demand, blood flow is directed to the active area (the haemodynamic response)

-fMRI produces 3D images (known as activation maps) showing which parts of the brain are involved in a particular mental process, which has important implications for our understanding of localisation of function in the brain.

strengths of fMRI

-doesnt rely on the use of radiation

-virtually risk free (if administered correctly), non-invasive and straightforward to use

-produces images that have high spatial resolution (depicts detail by the millimetre, and provides a clear picture of how brain function is localised, means fMRI can safely provide a clear picture of brain activity

limitations of fMRI

-expensive in comparison to other neuroimaging techniques

-poor temporal resolution (around a 5s