Biopsychology

Biopsychology

1. The Nervous System controls all biological processes and movements in the body and can be divided into two parts

   • Central Nervous System - passes messages to/from the brain and connects nerves to the PNS
     • Brain - centre of conscious awareness
     • Spinal cord - extension of the brain
   • Peripheral Nervous System (PNS) - controls sensory and relay neurons and is further divided into two parts
     • Automatic Nervous System (ANS) controls involuntary functions
       • Sympathetic nervous system
       • Parasympathetic nervous system
     • Somatic Nervous Sytem (SNS) controls voluntary functions

2. There are three types of neurons that carry neural information around the body

   • Sensory Neurons - unipolar neurons (they only transmit messages) that process information taken from one of the 5 senses to find out the current state of the body both inside and out
   • Relay Neurons - these multipolar neurons (transmit and receive information) are only located in the brain and spinal cord; they transport messages around the CNS, connecting sensory and moto neurons
   • Motor Neurons - also multipolar, motor neurons form synapses with muscles located in the CNS , to carry signals from the CNS to the glands and muscles to inform them of the required function

3. Synapse transmission:

   • Each neuron is seperated by a gap known as a synapse
     • Signals between neurons are transferred chemically via neurotransmitters
       • When an electric signal reaches the presynaptic terminal, it triggers the release of a neurotransmitter from the synaptic vesicle
         • The neurotransmitter diffuses across the synapse to the postsynaptic receptor site of the next neuron

4. Excitation vs Inhibition

   • Excitation - increases the positive charge of the postsynaptic neuron, increasing the chance the signal with be continued e.g. adrenaline
     • Inhibition - increases the negative charge of the postsynaptic neuron, decreasing the chance of the signal being continued e.g. serotonin

5. Gland types:

   • Pituitary - controlled by the hypothalamus, it regulates the endocrine system by releasing a hormone that signals to other glands which hormones need releasing
   • Adrenal - facilitates the release of adrenaline as part of the flight or fight response
   • Testes - facilitates the release of testosterone, responsible for male well being + development; Women have a small amount of it
   • Ovaries - facilitates the release of oestrogen and progesterone, the female hormones responsible for ovulation and the menstrual cycle

6. The fight or flight response

   • The hypothalamus percieves the situation as being stressful
     • The ANS changes from the parasympathetic (resting) state to the sympathetic (physiologically aroused) state
       • A hormone called ACTH is released from the pituitary gland
         • This hormone causes the adrenal gland to release adrenaline, which causes:
           • Increased alertness
           • Increased respiratory rate
           • Increased blood flow to muscles
           • Dilated pupils
           • Increased heart rate
           • Raised blood pressure
           • Reduced activity in digestive system to conserve energy