Biopsychology: Biochemistry (L1-5) Flashcards
1
Q
What does the CNS (central nervous system) consist of?
A
- the brain and spinal cord
2
Q
What are the 2 main functions of the CNS?
A
- control of behaviour
- regulation of the body’s physiological processes
- in order to do this the brain must be able to receive information from sensory receptions and send messages to the muscles and glands in response
3
Q
What 4 main areas is the brain split into?
A
- cerebrum
- cerebellum
- deincephalon
- brain stem
4
Q
Cerebrum (brain)?
A
- largest part of the brain
- has 4 lobes
- split down the middle into 2 halves, called the right and left hemisphere
5
Q
Cerebellum (brain)?
A
- responsible for motor skills, balance and coordinating muscles to allow precise movements
6
Q
Diencephalon (brain)?
A
- contains the thalamus, regulates consciousness, sleep and alertness
- and the hypothalamus, regulates body temp, stress response, hunger and thirst
7
Q
Brain stem?
A
- regulates breathing and heart rate
8
Q
What is the main function of the spinal cord?
A
- to relay information between the brain and the rest of the body
- allows the brain to monitor and regulate bodily
processes - such as digestion and breathing, and co-ordinate voluntary movement
9
Q
How is the spinal cord connected to the body?
A
- spinal cord is connected to different parts of the body by pairs of spinal nerves, which connect to specific muscles and glands
- if the spinal cord is damaged, body areas connected to it by nerves below the damage will be cut off and stop functioning
10
Q
What does the PNS (peripheral nervous system) consist of?
A
- the nervous system throughout the rest of the body
- not the brain or spinal cord
11
Q
What does the PNS do?
A
- transmits messages via neurons (nerve cells) to and from the CNS
12
Q
What are the 2 divisions of the PNS?
A
- somatic nervous system
- autonomic nervous system
13
Q
Somatic nervous system?
A
- controls voluntary movements and is under
conscious control - connects the senses with the CNS and has sensory pathways AND motor pathways
- controls skeletal muscles
- somatic nervous system is controlled by the motor cortex
14
Q
ANS (autonomic nervous system)?
A
- involuntary movements, not under conscious control
- ONLY has motor pathways
- controls smooth muscles and the internal organs and glands of the body
- ANS is controlled by the brain stem
15
Q
What is the ANS split into?
A
- SNS, sympathetic nervous system
- PNS, parasympathetic nervous system
16
Q
When is the SNS (ANS) activated and what happens?
A
- when a person is stressed
- heart rate and breathing increase, digestion stops, salivation reduces, pupils dilate, and the flow of blood is diverted from the surface on the skin
- fight or flight response
17
Q
When is the PNS (ANS) activated and what happens?
A
- when the body is relaxing and so conserving energy
- heart rate and breathing reduce, digestion starts, salivation increases, and pupils constrict
18
Q
What are neurons?
A
- specialised nerve cells that move electrical impulses to and from the CNS
19
Q
What are the parts to a neuron (7)?
A
- cell body
- nucleus
- dendrites
- axon
- myelin sheath
- Schwann cells
- nodes of Ranvier
20
Q
What is the cell body (neuron)?
A
- control centre of the neuron
21
Q
What is the nucleus (neuron)?
A
- contains genetic material
22
Q
What are dendrites (neuron)?
A
- receives an electrical impulse (action potential) from other neurons or sensory receptors
- e.g. eyes, ears, tongue and skin
23
Q
What is the axon (neuron)?
A
- a long fibre that carries the electrical impulse from the cell body to the axon terminal
24
Q
What is the myelin sheath (neuron)?
A
- insulating layer that protects the axon and speeds up the transmission of the electrical impulse
25
Q
What are Schwann cells (neuron)?
A
- make up the myelin sheath
26
Q
What are the nodes of Ranvier (neuron):
A
- gaps in the myelin sheath
- they speed up the electrical impulse along the axon
27
Q
Where are sensory neurons found?
A
- sensory receptors
28
Q
Function of sensory neurons?
A
- carry electrical impulses from the sensory receptors to the CNS (spinal cord and brain) via the Peripheral Nervous System (PNS)
- sensory neurons convert information from
sensory receptors into electrical impulses - when these impulses reach the brain they are converted into sensations, such as heat, pain etc.
- so that the body can react appropriately
- some sensory impulses terminate at the spinal
cord - this allows reflexes to occur quickly without the delay of waiting for the
brain to respond.
29
Q
Where are motor neurons found?
A
- in the CNS
- but protect their axons outside of the CNS
30
Q
Function of motor neurons?
A
- send electrical impulses via long axons to the glands and muscles so they can respond
- glands and muscles are called effectors
- when motor neurons are stimulated they release neurotransmitters that bind to the
receptors on muscles to trigger a response - leads to movement
31
Q
Where are relay neurons found?
A
- found in the CNS
32
Q
Function of relay neurons?
A
- connect sensory neurons to motor neurons so that they can communicate with one another
- during a reflex arc (e.g. you put your hand on a hot hob) the relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond
- (e.g. to lift your hand) without waiting for the brain to process the pain
33
Q
How do neurones send signals to one another?
A
- through synaptic transmission
- transmit electrical impulses known as action potentials
- between pre-synaptic neurone, neurone transferring action potential
- and post-synaptic neurone, neurone receiving the action potential
34
Q
How does synaptic transmission work?
A
- action potential reaches the pre-synaptic terminal
- triggers the release of neurotransmitters from sacs on the pre-synaptic membrane known as vesicles, in a process called exocytosis
- released neurotransmitter will diffuse across the synaptic cleft, physical gap between the pre-synaptic membrane and post-synaptic membrane
- where it binds to specialised post-synaptic receptor sites on the post-synaptic membrane
34
Q
How are the effects of synaptic transmission terminated?
A
- synaptic transmission takes only fraction of second
- effects terminated by process called re-uptake
- neurotransmitter is taken back by the vesicles on the pre-synaptic neurone where they are stored for later release
- the quicker the neurotransmitter taken back the shorter the effects
35
Q
Neurotransmitters can be…
A
- excitatory
- inhibitory
36
Q
What are excitatory neurotransmitters?
A
- promotes the generation of an electrical signal called an action potential in the receiving neuron
- resulting in an excitatory post-synaptic potential, EPSP
- meaning that the post-synaptic neurone is more likely to fire an impulse
37
Q
What are inhibitory neurotransmitters?
A
- prevents the generation of an electrical signal called an action potential in the receiving neuron
- resulting in an inhibitory post-synaptic potential, IPSP
- meaning that the post-synaptic neurone is less likely to fire an impulse
38
Q
What happens if a neurone receives both EPSPs and IPSPs at the same time?
A
- likelihood that the neuron will fire an impulse is determined by adding up the excitatory
and the inhibitory synaptic input - the net result of this calculation, known as
summation, determines whether or not the neuron will fire an impulse - if the net effect is inhibitory the neuron will not fire
- and if the net effect is excitatory, the neuron will fire
39
Q
What is the direction of synaptic transmission?
A
- Information can only travel in ONE direction at a synapse
- the vesicles containing neurotransmitters are ONLY present on the pre-synaptic
membrane - the receptors for the neurotransmitters are ONLY present on the post-synaptic membrane
- it is the binding of the neurotransmitter to the
receptor which enables the information to be transmitted to the next neuron - diffusion of the neurotransmitters mean they can only go from high to low
concentration, so can only travel from the pre-synaptic membrane to the post-
synaptic membrane
40
Q
How can knowledge on neurotransmitters be used in medication?
A
- use of psychoactive drugs which affect brain function to alter perception, mood or behaviour
- like SSRIs which affect the transmission of neurotransmitters across a synapse
- some pain medications mimic effects of inhibitory neurotransmitters
- stimulation of postsynaptic receptors by inhibitory neurotransmitter
results in inhibition of postsynaptic membrane - when an inhibitory
neurotransmitter binds to the post-synaptic receptors it makes the post-synaptic neuron less likely to fire - due to summation, if inhibitory
neurotransmitters are higher than excitatory neurotransmitters they can
inhibit an action potential from occurring - so pain medications would
decrease the overall activity and reducing brain activity may lead to less pain
41
Q
What is the endocrine system?
A
- provides a chemical system of communication in the body
via the blood stream - consists of endocrine glands that produce and secrete hormones into the bloodstream
- these are required to regulate many bodily functions
- major glands of the endocrine system include the pituitary gland and the adrenal glands
- each gland produces different hormones which regulate activity of organs/tissues in the body
42
Q
How do hormones work?
A
- come into contact with most cells in the body
- but only affect a limited number, known as target cells
- target cells respond to a particular hormone as they have receptors for that hormone
- when enough receptor sites are stimulated by that hormone there is a physiological reaction
43
Q
What is the pituitary gland?
A
- located in brain and controlled by the hypothalamus
- controls release of hormones from all other glands
- e.g. produces ACTH involved in stress response to stimulate cortisol production and release from adrenal glands
- has 2 divisions
44
Q
What are the 2 divisions of the pituitary gland?
A
- anterior, releases hormone ACTH which regulates levels of hormone cortisol
- posterior, responsible for releasing hormone oxytocin crucial for infant/mother bonding
45
Q
What are adrenal glands?
A
- glands involved in fight or flight response
- we have 2 adrenal glands situated on each kidney
- each adrenal gland is made up of 2 distinct parts, cortex and medulla
- the gland produces adrenaline which triggers the fight or flight response
- leads to increase in heart and breathing rate and contracts blood vessels
46
Q
What is the adrenal cortex?
A
- outer section of the adrenal gland
- produces hormone cortisol which is produced in high amounts when someone experiencing chronic stress
- cortisol also responsible for the cardiovascular system
- will increase blood pressure and causes blood vessels to constrict
47
Q
What is the adrenal medulla?
A
- inner section of the adrenal gland
- produces adrenaline, the hormone that is needed for the fight or flight response
- activated when someone is suddenly stressed
- adrenaline increases heart rate, dilates pupils and stops digestion
48
Q
How is the fight or flight response generated?
A
- during stressful situation the response is generated by the sympathetic branch of autonomic nervous system
- sympathetic nervous system is triggered by the hypothalamus
- the SNS stimulates the adrenal medulla to release adrenaline into the bloodstream
49
Q
What are the effects of adrenaline?
A
- increased heart rate
- constricted blood vessels, increasing rate of blood flow and raising blood pressure
- blood diverted away from the skin, kidneys and digestive system
- increased respiration
- increased sweating
- pupil dilation
- saliva production stopped, can cause dry mouth
- digestion is inhibited, can cause butterflies in stomach or nausea
- glucose released, increasing blood sugar levels, fuel for muscles
- muscles tense for rapid response, can cause shaking
- increased blood supply to the brain and skeletal muscles, can cause limbs to shake
50
Q
What are the general effects of adrenaline?
A
- to prepare the body for physical action by increasing blood supply/oxygen to
skeletal muscles - and prepare for rapid response planning by increasing the oxygen supply to the brain
51
Q
What does the parasympathetic system do?
A
- when threat has passed PNS dampens stress response
- adrenaline levels return to normal which returns heart/breathing rate to normal
- digestion, which is stopped when SNS is active, restarts
- rest and digest
52
Q
+ve Evaluation fight or flight response:
A
- makes sense from an evolutionary psychology point of view
- as it would have helped an individual to survive by fighting or fleeing a threat
= studies support claim that adrenaline essential in preparing body for stress
= people who have malfunctioning adrenal glands do not have a normal fight or flight response to stress
53
Q
-ve Evaluation fight or flight response:
A
- Gray states that first reaction to stress is not to fight or flight
but freeze - involves person stopping, looking and listening and being
hyper vigilant to danger
= Taylor found females tend and befriend in times of stress
= tend and befriend refers to the protection of offspring (tend) and seeking out social
groups for mutual defence (befriend)
= women have hormone oxytocin which means they are more likely to stay and protect their offspring - Von Dawans found even males also tend and befriend
- during the 2001 September 11th terrorist attacks both males and females showed tend and befriend
- as they tried to contact loved ones and help one another
