4.2.2 Biopsychology Flashcards
1
Q
the nervous system
A
- the main system that controls the mind and body
- divided into two parts;
- the central nervous system (CNS)
- the peripheral nervous system (PNS)
2
Q
the central nervous system (CNS)
A
- made up of the brain and the spinal cord
- the brain is central to maintaining life and has many functions, including;
- language production and understanding
- co-ordinating movement
- coding sensory data from sensory organs
- regulates bodily processes based on info from the peripheral nervous system
- sleep
- the spinal cord connects the brain with the peripheral nervous system;
- it ensures that signals from the brain are transmitted to the rest of the body via the PNS
- it’s also involved in unconscious movements, i.e. reflex actions
3
Q
the peripheral nervous system
A
- consists of nerves which branch out from the brain and spinal cord, forming the communication network between the CNS and the rest of the body
- transmits messages throughout the whole body from the brain and relays messages back to the brain
- divided into two sections;
- the somatic nervous system
- the autonomic nervous system
4
Q
the somatic nervous system
A
- transmits and receives messages from the senses
- responsible for voluntary movement and is under conscious control
5
Q
the autonomic nervous system
A
- transmits and receives info from the organs
- responsible for involuntary movement and isn’t under conscious control
- divided into two further sections;
- the sympathetic system (increases activity)
- the parasympathetic system (decreases activity to conserve the body’s energy)
6
Q
neurons
A
- these are cells within the nervous system that transmit info as electrical impulses throughout the body
- thought to be around 100 billion neurons in the brain and over 1 billion in the spinal cord
- there are 3 main types of neuron;
- sensory
- relay
- motor
7
Q
structure of neurons
A
- all 3 types of neuron have the same general structure;
- the dendrite (receptor) receives a signal
- the signal is carried towards a cell body (which contains the nucleus)
- the signal travels along an axon towards the axon terminal
- synaptic terminals / ending at the end of the axon pass the electrical signal to the next neuron
- sensory and motor neurons are myelinated; they have myelin sheath (an insulating layer) which protects axons and allows impulses to jump between the nodes of ranvier (gaps in the myelin sheath), therefore it speeds up transmission of an impulse
8
Q
sensory neurons
A
- diagram 1
- they carry info from receptors in the PNS towards the CNS
- they keep the brain informed about the external and internal environment via processing info coming from sense organs
- dendrites, cell body and axon in the PNS and synaptic terminals in the CNS where they connect to relay neurons
- myelinated neurons
- they’re unipolar as they can only transmit messages
9
Q
relay neurons
A
- diagram 2
- they connect sensory neurons to motor neurons
- they’re based in the CNS
- unmyelinated neurons
- they’re multipolar as they can both transmit and receive messages
10
Q
motor neurons
A
- diagram 3
- they carry signals from the CNS to organs, muscles and glands in the body (effectors)
- cell body in the CNS and the rest of the nerve in PNS
- myelinated neurons
- multipolar neurons as they can both transmit and receive messages
11
Q
reflex arc
A
- a neural pathway that controls a reflex action
- stages of a reflex arc;
- a stimulus is detected by sense organs in the PNS, e.g. change in temperature if we touch something hot
- sense organs convey a message along a sensory neuron
- message reaches CNS
- CNS connects with a relay neuron
- relay neuron transfers message to a motor neuron
- motor neuron carries message to an effector, e.g. a muscle
- this causes a reflex response, e.g. muscle contracts to move hand away from hot object
12
Q
synapses
A
- the gap between two neurons
- consists of a pre-synaptic membrane, synaptic cleft and post-synaptic membrane
- signals within neurons are transmitted electronically, but signals between neurons are transmitted chemically, as electrical impulses can’t jump across synapses
13
Q
synaptic transmission
A
- diagram 4
- the process of sending info from one neuron to another
- info is passed down the axon of a neuron as an electrical impulse (action potential)
- the pre-synaptic membrane contains vesicles, which release neurotransmitters (chemical messengers) that diffuse across the synaptic cleft and bind to receptors in the post-synaptic membrane
- this stimulates the post-synaptic membrane to generate an electrical impulse that then travels down the axon of the post-synaptic neuron
- to prevent continued stimulation of the second neurone, the neurotransmitters are then recycled as they’re released from receptors, taken back up by the pre-synaptic membrane and repackaged into vesicles, or they may be destroyed by being degraded by enzymes in the synapse
14
Q
excitation and inhibition
A
- neurotransmitters can have either excitatory (positive) or inhibitory (negative) effects
- excitatory; increases the likelihood of the neuron firing an impulse (depolarisation), e.g. dopamine
- inhibitory; decreases the likelihood of the neuron firing an impulse (hyperpolarisation), e.g. serotonin
15
Q
summation
A
- the process of adding (‘summating’) the excitatory and inhibitory signals from the neurotransmitters to determine the net effect and therefore whether or not an action potential will be generated
- spatial summation; involves simultaneous signals from multiple presynaptic neurons being received by a postsynaptic neuron
- temporal summation; involves a single presynaptic neuron rapid-firing signals to a postsynaptic neuron
16
Q
the endocrine system
A
- diagram 5
- a system of glands that secrete hormones into the bloodstream, which produces an effect upon reaching a target cell / organ
- transmits info chemically
- operates much slower than the nervous system
17
Q
structures in the endocrine system
A
- hypothalamus; stimulates and controls release of hormones from pituitary gland
- pituitary gland; ‘master gland’ which produces hormones that control the release of hormones from other glands, e.g. FSH and LH
- pineal gland; melatonin for sleep regulation
- thyroid gland; thyroxine to control metabolism
- pancreas; insulin (decreases) and glucagon (increases) to control blood sugar levels and digestive enzymes, e.g. amylase and lipase
- adrenal gland; adrenaline for fight or flight response
- ovaries (female); oestrogen, i.e. female sex hormone, and progesterone which regulates uterus for pregnancy and is also made by the placenta
- testes (male); testosterone, i.e. male sex hormone
18
Q
pituitary gland
A
- connects the endocrine system to the nervous system via the hypothalamus
- secretes hormones which act on other glands to stimulate the release of other hormones to bring about certain effects
- split into anterior (front) and posterior (rear) lobes
- anterior lobes produce peptide hormones, e.g. FSH, LH, growth hormone, thyroid -stimulating hormone (TSH) which stimulates the thyroid to release thyroxine, and adrenocortical trophic hormone (ACTH) which stimulates the adrenal cortex and the release of cortisol
- posterior lobes produce vasopressin (regulates blood pressure) and release oxytocin (responsible for uterus contractions during childbirth)
19
Q
fight or flight response
A
- preparing the body for action (either fighting or fleeing) upon sensing a threat;
- the body senses a threat
- through sensory neurons in the PNS, this info is sent to the hypothalamus in the brain which coordinates a response and triggers increased levels of activity in the sympathetic branch of the ANS
- this stimulates the adrenal medulla within the adrenal glands to release adrenaline and noradrenaline which is transported to target effectors via the bloodstream
- different bodily activities are increased to either fight or flee from the threat
- once the brain senses that the threat has passed, the parasympathetic nervous system kicks in to reduce these activities and returns the body to a resting state (rest and digest response)
20
Q
adrenaline in the fight or flight response
A
- adrenaline increases bodily activities to either fight or flee from the threat, e.g;
- blood pressure and heart rate increase to supply blood to the muscles at a faster rate
- breathing rate increases so more oxygen can be sent to muscles
- muscles become more tense so the body is physically responsive
- salivation decreases as the digestion system decreases so that more blood can be directed to the muscles
- pupil size increases so more light can enter the eyes, allowing for clearer vision
21
Q
localisation of function in the brain
A
- diagram 6
- more modern approach as early scientists saw the brain in a holistic way (all areas used for all function)
- localisation suggests that certain functions have specific locations in the brain;
- motor cortex; responsible for voluntary movement and is located in the frontal lobes
- somatosensory cortex; responsible for sensing physical sensations on your skin (touch), i.e. pressure, heat, etc., and is located in the parietal lobes
- auditory cortex; responsible for processing sound and is located in the temporal lobes
- visual cortex; responsible for processing visual info from the eyes and is located in the occipital lobes
22
Q
hemispheric lateralisation
A
- diagram 7
- dividing the brain into two hemispheres; a left and right one
- the two hemispheres are connected by the corpus callosum (a bundle of nerve fibres) which acts as a bridge and allows them to send messages and work together. info passes through this to whichever side of the brain needs to deal with it
- each hemisphere has 4 brain lobes;
- frontal lobe; prefrontal area, motor cortex, Broca’s area
- temporal lobe; auditory cortex, Wernicke’s area
- parietal lobe; somatosensory cortex
- occipital lobe; visual cortex
- there is also a cerebellum which controls balance, coordination and the brain stem, which controls involuntary responses
- in general, the hemispheres are contralateral, i.e. info from the left side of the body is processed by the right hemisphere and vice versa
- e.g. damage to the motor cortex in the right hemisphere will affect the person’s ability to move their left side
- the left hemisphere is called the ‘dominant’ one as it’s generally responsible for language and speech, logic, analysis and problem solving
- the right hemisphere is generally more concerned with spatial reasoning, interpreting visual info and recognising emotions (facial expressions)
23
Q
language centres
A
there are two areas, located in the left hemisphere, particularly important for language; Broca’s area and Wernicke’s area