Biopsychology

• The Nervous System:

  Two functions:

  • To collect, process and respond to information in the environment.
  • To coordinate the working of different organs and cells in the body.
• The Nervous System:

  The Central Nervous System:

  • The brain and spinal cord
  • Brian’s outer layer- cerebral cortex, 3mm thick
  • Brain is divided into 2 hemispheres.
  • The spinal cord is an extension of the brain- passes messages to and from the brain and connects nerves to the PNS.
  • Spinal cord is also responsible for your reflex actions. 
• The Nervous System:

  The Peripheral Nervous System:

  • Transmits messages via million of neurons, to and from the CNS. 
  • It is further subdivided into:
  • Autonomic nervous system- governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress response.
  • Somatic nervous system- governs muscle movement and receives information from the sensory receptors.
• The Endocrine System:

  • Hypothalamus - stimulates and controls the release of hormones from the pituitary gland.
• The Endocrine System:

  • Pituitary - releases ACTH - regulates the glucecontrocoid (steroid) hormones cortisol - releases Oxytocin - increases contractions to induce labour and birth and the release of milk from the breast after birth, provides caregiving reponse.
• The Endocrine System:

  Pineal - releases Melatonin - helps with the timing of your circadian rhythms (24 hour internal clock) and induces sleep.
• The Endocrine System:

  • Thyroid - releases Thyroxine - affects cells in the heart (increases heart rate). Affects cells throughout the body, increasing the metabolic rate (affects growth rate).
• The Endocrine System:

  Adrenal - releases Adrenaline (medulla) - triggers psychological changes in the body (increased heart rate) which creates psychological arousal necessary for fight or flight - releases Cortisol (cortex) - regulates blood pressure, blood sugar, immune system and response to stress.
• The Endocrine System:

  Ovaries - releases Oestrogen - menstrual cycle, pregnancy.
• The Endocrine System:

  • Testes - releases Testosterone - regulates sex drive, bone mass, fat distribution, muscle mass and strength and the production of red blood cells and sperm. 
• Types of Neurons:

  Sensory Neuron:

  • Located outside of the CNS and in the PNS in clusters known as ganglia.
• Types of Neurons:

  Relay neuron:

  • Make up 97% of all neurons and most are found within the brian and the visual system.
• Types of Neurons:

  Motor Neuron:

  • May be in the CNS but they have long axons which form part of the PNS
• Synaptic transmission: 1

  • When a neurotransmitter crosses through the synaptic gap it can have either an excitatory or an inhibitory effect on the postsynaptic neurons.
• Synaptic transmission: 2

  • Excitation occurs when receptor stimulation results in an increase in the positive charge of the postsynaptic neuron and increases the likelihood of the neuron firing and passing on the electrical impulse. (Adrenaline)
• Synaptic transmission: 3

  • Inhibition occurs when receptor stimulation results in an increase in the negative charge of the postsynaptic neuron and decreases the likelihood of the neuron firing and passing on the electrical impulse.