1.1 Biopsychology Flashcards
What is the nervous system?
A specialized network of cells in the human body that act as our primary internal communication system
What are the 2 subsystems of the nervous system?
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
What are the 2 main functions of the nervous system?
- To collect, process and respond to information in the environment
- To co-ordinate the working of different organs and cells in the body
What is the central nervous system (CNS)?
Consists of the brain and the spinal cord and is the origin of all complex commands and decisions
What is the peripheral nervous system (PNS)?
Sends information to the CNS from the environment, and transmits messages from the CNS to muscles and glands in the body
What are the 2 subdivisions of the PNS?
- Autonomic nervous system (ANS)
- Somatic nervous system (SNS)
What is the role of the somatic nervous system (SNS)?
Governs muscle movement and receives information from sensory receptors
What is the role of the autonomic nervous system (ANS)?
Governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
What is the endocrine system?
A network of glands across the body that secretes hormones + works alongside nervous system
Name the 8 main glands in the endocrine system
- Hypothalamus
- Pituitary
- Thyroid
- Parathyroid
- Adrenals
- Pancreas
- Ovaries
-Testes
What is the role of the pituitary gland and where is it located?
- Located in the brain
- Controls the release of hormones from all other endocrine glands in the body (‘master gland’)
What is the role of the thyroid gland?
Releases thyroxine which affects cells in the heart (increases heart rate) and throughout the body (increases metabolic rates), therefore affects growth rates
Describe how the endocrine system and ANS work together
- When a stressor is perceived, the hypothalamus activates the pituitary gland triggering activity in the sympathetic branch of the ANS
- ANS changes from its normal parasympathetic state to its psychologically aroused state sympathetic
- ‘Fight or flight’ is triggered
What is the difference between the parasympathetic state and the sympathetic state?
- Parasympathetic is the body’s normal state when it is relaxed, resting or feeding
- Sympathetic is a state of physiological arousal, preparing the body for fight or flight
What is adrenaline and its purpose?
- A stress hormone (released from the adrenal medulla)
- Triggers physiological changes in the body e.g heart rate creating the arousal necessary for fight or flight
What is a gland?
An organ in the body that synthesises substances such a as hormones
What is a hormone?
Chemical messengers released from endocrine glands that circulate the blood but only affect target organs
What is the role of the parasympathetic nervous system?
Returns the body to its natural resting state, acting as a brake and reducing the activities of the body that were increased by the sympathetic branch (reset and digest response)
What are 3 features of the parasympathetic state?
- Decreases heart and breathing rate
- Stimulates digestion
- Constricts pupils
What are 3 features of the sympathetic state?
- Increased heart and breathing rate
- Inhibits digestion
- Dilates pupils
How does the PNS transmit messages?
Via millions of neurons
What is the main difference between the nervous system and endocrine system
- Nervous system: based on electrical and chemical signals
- Endocrine system: based on hormones
What is the function of the spinal cord?
An extension of the brain. Passes messages to and from the brain and connects nerves to PNS
What is the outer layer of the brain called?
Cerebral cortex (only 3mm thick)
Describe the role of the endocrine system
Instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body.
What are neurons?
Nerve cells that process and transmits messages through electrical and chemical signals
What are the 3 types of neurons?
- Sensory neuron
- Relay neuron
- Motor neuron
State the 2 ways neurons transmit signals?
- Signals within neurons transmitted electrically
- Signals between neurons transmitted chemically
Describe the features of a sensory neuron, its role and where its located?
- Long dendrites and short axons
- Carry messages from the PNS to the CNS
- Located in receptors such as eyes and ears
Describe the features of a relay neuron, its role and where its located?
- Short dendrites and short axons
- Connect the sensory neurons to the motor and other neurons
- Located in the brain and spinal cord
Describe the features of a motor neuron, its role and where its located?
- Short dendrites and long axons
- Connects the CNS to effectors such as muscles and glands
- Located in the CNS
Name the features of a neuron
- Cell body: Includes a nucleus, genetic material
- Dendrites: branch-like structures that protrude from the cell body
- Axon
- Nodes of Ranvier
- Terminal buttons
What is the role of dendrites?
To carry nerve impulses from neighbouring neurons towards the cell body
What is the purpose of a myelin sheath?
Protects the axon and speeds up electrical transmission of the impulse
What is the role of the axon?
Carries impulses away from the cell body down the length of the neuron
What is the role of the nodes of Ranvier?
Speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon
What is the role of terminal buttons?
Communicate with the next neuron in the chain across the synapse
Describe the process of electrical transmission
- When the inside of the cell is negatively charged compared to the outside (as the neuron is in its resting state)
- When the neuron is activated by a stimulus, it becomes positively charged causing action potential to occur
- Creates an electrical impulse that travels towards the end of the neuron
What is synaptic transmission?
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synapse
What is a neurotransmitter?
Chemicals that diffuse across the synapse, allowing neurons in the body to communicate with each other
What is excitation and what does it lead to?
- When a neurotransmitter increases the positive charge of the postsynaptic neuron
- Increases the likelihood that the postsynaptic neuron will pass on the electrical impulse
What is inhibition and what does it lead to?
- When a neurotransmitter increases the negative charge of the postsynaptic neuron
- Decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse
What happens when an electrical impulse reaches the end of a neuron?
It triggers the release of the neurotransmitter from tiny sacks called synaptic vesicles
Describe the process of summation
- The excitatory and inhibitory influences are summed, the net effect affects the likelihood of what occurs
- The action potential is only triggered if the sum of excitatory or inhibitory signals at any one time reaches the threshold
Describe the process of synaptic transmission
- When an electrical impulse arrives on the presynaptic neuron, neurotransmitters are released from synaptic vesicles
- The neurotransmitters diffuse across the synaptic cleft and bind to the postsynaptic receptor sites
- The chemical message is converted into an electrical impulse and the process begins again
