Biopsychology Flashcards
What does the CNS comprise of?
- brain
- spinal chord
What is the function of the spinal chord? - what does this allow?
To relay information between the brain and the rest of the bod.
This allows the brain to regulate and monitor bodily processes such as digestion and breathing and to coordinate bodily movements
What does the spinal chord contain?
Circuits of nerve cells that enable us to perform some simple reflexes (e.g. pulling your hand away from something hot)
What would happen if your spinal chord is damaged?
Areas supplied by spinal nerves below the damaged site will be cut off from the brain and will stop functioning
What are the four min areas of the brain?
- cerebrum
- diancephalon
- cerebellum
- brain stem
What is the Cerebrum?
- The largest part of the brain
- it is further divided into 4 lobes
Describe the functions of 2 lobes in the Cerebrum
- The frontal lobe is involved in thought and production of speech
- The occipital lobe (at the back of the cerebrum) is involved in processing visual images
The Cerebrum is split into two halves, what are these called?
Cerebral hemispheres
How do cerebral hemispheres communicate with others?
Through the corpus Callosum
What does the Cerebellum do?
Controlls a persons monitor skills and balance, coordinating the muscles to allow precise movements.
Where does the Cerebellum sit?
Beneath the back of the cerebrum
What may abnormalities in the Cerebellum result in?
Speech and motor problems and epilepsy
Where does the diacephalon lie?
Beneath the cerebrum and on top of the brain
What are the two important structures within the diacephalon?
- the thalamus
- the hypothalamus
What does the thalamus do?
-It acts as a relay station for nerve impulses coming from the senses, routing them to appropriate part of the brain where they can be processed.
What does the hypothalamus do?
- Regulation of body temperature, hunger and thirst
- Acts as a link between the endocrine system and the nervous system, controlling the release of hormones from the pituitary gland
What does the brain stem do?
Regulates the automatic functions that are essential for life such as breathing, heartbeat and swallowing
What neurons pass through the brain stem?
Motor and sensory neurons, these allow impulses to pass between the brain and the spinal chord
What are the two main processes of the CNS?
- the control of behaviour
- the regulation of the body’s psychological processes
What is the peripheral nervous system?
All the nerves outside the CNS
What is the function of the peripheral nervous system?
To relay nerve impulses from the CNS to the rest of the body and from the body back to the CNS
What are the two main divisions of the peripheral nervous stem?
- The autonomic nervous system
- The somatic nervous system
What is the somatic nervous system made up of?
- 12 pairs of cranial nerves (nerves that emerge directly from the underside of the brain)
- 31 pairs of spinal nerves (nerves that emerge from the spinal chord)
What do sensory neurons do?
Relay messages to the CNS
What do motor neurons do?
Relay neurons from the CNS to other areas of the body
How does the somatic system allow reflex actions to occur quickly?
It is involved in reflex actions without the involvement of the CNS
What does the autonomic nervous system do?
- actions without conscious awareness
e. g your heart beats and your intestines digest food without you being consciously aware of this happening
Why is the autonomic nervous system necessary?
Because if you had to think about vital bodily functions such as heartbeat and digestion they would not work as well
What are the two parts of the ANS?
- The sympathetic
- The parasympathetic
What are the neurotransmitters used by the parasympathetic division?
Acetylcholine which has inhibiting effects
What are the neurotransmitters used by the sympathetic division?
Noradrenaline which has stimulating effects
What is the sympathetic nervous system primarily involved in?
Responses that help us to deal with emergencies (fight or flight) such as increasing heart rate and blood pressure and dilating blood vessels in the muscles
Give some examples on the effects of SNS activation in the body
- Increased pupil size lets in more light for better vision
- Increase in heart rate allows for greater blood flow to skeletal muscles
- Glycogen stored in the liver converted to glucose for energy
- Bronchial tubes in lungs dilate for greater oxygen intake
- sweat glands stimulated to produce more sweat
- adrenal medulla stimulated to release adrenaline
What does the parasympathetic nervous stem do?
-relaxes someone once the emergency has passed (after the SNS has pushed an individual into action due do an emergency)
Give examples of the effects of PNS activation in the body
- PNS slows the heartbeat down and reduces blood pressure
- Digestion (which is inhibited when SNS is aroused) begins under PNS influence
- because the PNS is involved with energy conservation and digestion it is sometimes referred to as the bodys rest and digest system
What are neuron cells?
Cells that are specialised to carry neural information throughout the body
What are the three types of neuron cells?
- sensory neurons
- relay neurons
- motor neurons
What do dendrites typically consist of?
- a cell body
- dendrites
- an axon
What is the control centre of a neuron?
The cell body
What is the insulating layer that forms around the axon?
The Myelin sheath
What happens if the myelin sheath is damaged?
Impulses slow down as the myelin sheath allows nerve impulses to travel more rapidly along the axon.
What do sensory neurons do?
Carry nerve impulses from sensory receptors (e.g to the receptors for vision, taste, touch) to the spinal chord and brain.
How do sensory neurons function?
- they convert information from these sensory receptors (e.g the receptors for vision, taste, touch) into nerve impulses
- when these impulses reach the brain, they are translated into sensations, for example visual input, pain etc. so the organism can react appropriately
How can reflex actions occur quickly when sensory neurons are involved?
Because not all sensory information travels as far as the brain, with some neurons terminating in the spinal chord
-therefore you do not have the delay of sending impulses to the brain.
What do relay neurons do?
- most neurons are neither sensory or motor, but lie somewhere between the sensory input and motor output
- relay neurons allow sensory and motor neurons to communicate with eachother
- they lie wholly within the brain and spinal chord
What do motor neurons do?
Form synapses with muscles and control their contractions
Where are motor neurons located?
-the neurons are located in the CNS and project their axons outside the CNS and directly or indirectly control muscles
How do motor neurons form synapses with muscles and control their contractions?
- When stimulated the motor neuron releases neurotransmitters that bind to receptors on the muscle and triggers a response which might lead to muscle movement .
- When the axon of a motor neuron fires, the muscle with which it has formed synapses with contracts
What does the strength of muscle contraction depend on?
-the rate of firing of the axons of motor neurons that control it
What is muscle relaxation caused by?
The inhibition of a motor neuron
Describe synaptic transmission
- once an action or potentials arrived at the terminal button the end of an axon, it needs to be transferred to another neuron or tissue
- to do this it must cross a gap between the presynaptic neuron and postsynaptic neuron
- the physical gap between the pre- and postsynaptic gap is known as the synaptic gap
- at the end of the axon of the nerve cell are a number of sacs known as synaptic vesicles
- these vesicles contain chemical messengers that assist in the transfer of the impulse, the neurotransmitters
- as the action potential reaches the synaptic vesicles, it causes them to release their contents through a process known as exocytosis
- the released neurotransmitter diffuses across the gap between the pre- and postsynaptic cell, where it binds to specialised receptors on the surface of the cell that recognise it and are activated by that certain neurotransmitter
- once they have been activated, the receptor molecules produce either excitatory or inhibitory effects on the postsynaptic neuron