Biopsychology Flashcards
(21 cards)
The nervous system
Central nervous system and Peripheral nervous system
Central nervous system
The brain is the centre of all conscious awareness.
The spinal cord is an extension of the brain. It is responsible for reflex actions.
It passes messages to and from the brain and connects nerves to the PNS.
Peripheral nervous system
Transmits messages, via neurons, to and from the CNS.
Further sub-divided:
- AUTONOMIC NERVOUS SYSTEM - governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses.
- SOMATIC NERVOUS SYSTEM - controls muscle movement and recieves information from sensory receptors.
The endocrine system
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream, which are then carried towards target organs in the body.
Hypothalamus
Produces oxytocin and ADH.
Controls weight, hunger and body temperature.
Pituitary
The ‘master’ gland, controls the endocrine system.
Thyroid
Produces thyroxine.
Increases heart rate and the metabolic rate. This affects growth rates.
Parathyroid
Produces parathyroid hormone.
Helps control calcium levels.
Adrenals
Produces adrenalin.
Triggers fight or flight response.
Pancreas
Produces insulin.
Controls blood sugar levels and helps the digestive system.
Ovaries
Produces oestrogen.
Prepares the body for pregnancies.
Testes
Produces testosterone.
Increases aggression levels and increases hair growth.
Sensory neuron
Carries messages from the PNS to the CNS.
Long dendrites and short axons.
Relay neuron
Connect the sensory neurons to the motor or other relay neurons.
Short dendrites and short axons.
Motor neuron
Connects CNS to effectors such as muscles and glands.
Short dendrites and long axons.
Structure of a neuron
Dendrites Cell body Nucleus Myelin sheath Axon Axon terminal
Synaptic transmission
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synapse that separates them.
What happens during synaptic transmission?
The message arrives at the neuron as a chemical message, that turns into an electrical impulse when it reaches the dendrite. It travels through the axon as an electrical impulse and when it reaches the axon terminal it changes into a chemical neurotransmitter, so it can diffuse across the synapse, into the dendrites of the next neuron.
Excitation
When a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron.
This INCREASES the likelihood that the neuron will fire and pass on the electrical impulse.
Inhibition
When a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron.
This DECREASES the likelihood that the neuron will fire and pass on the electrical impulse.
Fight or Flight
The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or, in some cases, flee.
The endocrine system and the Autonomic nervous system often work in parallel with each other, e.g. in a stressful situation.
When a stressor is perceived (e.g. thinking about an upcoming exam) the Hypothalamus triggers activity in the sympathetic branch of the autonomic nervous system. The ANS changes form its normal resting state (the parasympathetic state) to the physiologically aroused, sympathetic state.
Adrenaline is released from the adrenal medulla into the bloodstream. Adrenaline triggers psychological changes in the body e.g. increased heart rate, which creates the psychological arousal necessary for the flight or fight response.
All of this happens in an instant as soon as the threat is detected and is an autonomic reaction in the body. These changes explain why stress, panic or even excitement is often experienced as a ‘sick’ feeling.
Once the threat has passed, the parasympathetic nervous system returns the body to its resting state.
