structures of the brain Flashcards
describe the central nervous system
- compromises brain and spinal cord
- brain consists of 4 main lobes and processes info from our senses
- brainstem connects brain and spinal cord + controls involentary processes eg. heartbeat
- spinal cord transfers msgs from brain to rest of the body + responsible for simple reflex actions that don’t involve the brain
describe the peripheral nervous system
- consists of autonomic nervous system and somatic nervous system
- responsible for transmitting msgs to and from the CNS to the rest of the body
describe the somatic nervous sytstem
- facilitates comms between CNS and outside world
- made up of sensory receptors which carry info to spinal cord and brain and motor pathways that allow brain to control movement
describe the autonomic nervous system
- plays important role in homeostasis
- only consists of motor pathways and consists of PNS and SNS
what is the function of the cell body
- helps sustain life of neuron
- contains nucleus –> DNA
what is the function of the nucleus
- contains DNA
- controls neuron
what is the function of the axon
carries electrical signals from the dendrites to the terminal
what is the function of the dendrites
to receive messages from other neurons
what is the function of the vesicles
where the neurotransmitters are stored
what is the function of the myelin sheath
acts as insulator to speed up impulse
what is the structure of the sensory neuron
- long dendrites
- short axons
what is the structure of the relay neuron
- short dendrites
- short axons
what is the structure of the motor neuron
- short dendrites
- long axon
what is the function of sensory neurons
carries messages from the PNS to the CNS
what is the function of relay neurons
to connect the sensory neurons to the motor or any other relay neurons
what is the function of motor neurons
connects the CNS to effectors such as muscles and glands
insert synapse here
describe the process of synaptic transmission
- electrical impulses (action potential) reach the pre-synaptic neuron
- this triggers the release of neurotransmitters from synaptic vesicles
- neurotransmitters diffuse across synaptic gap
- neurotransmitters then bind to receptors on the postsynaptic membrane
what are the two typrs of neurotransmitters you can have
- excitatory
- inhibitory
describe excitatory neurotransmitters
- the nervous system’s ‘on switch’
- increase likelihood that excitatory signal is sent to postsynaptic neuron
when an excitatory NT binds with a postsynaptic receptor:
- it results in an excitatory postsynaptic potential (EPSP)
- the postsynaptic neuron is more likely to fire
how does the endocrine system work
- controls vital functions in the body
- acts more slowly than nervous system
- yet effect is widespread and powerful
what are the functions of the endocrine system
- regulates organ activity and controls physiological processes in the body
- releases hormones/chemical messengers from glands into the bloodstream which then bind to receptors to regulate activity of cells/organs
describe the pituitary gland
- ‘master gland’
- controls hormones
describe the anterior pituitary
- ACTH
- releases cortisol during chronic stress and suppresses immune system
describe the posterior pituitary
releases oxitonin –> happy feeling
- helps uterus contract during pregnancy
describe the adrenal glands
adrenal cortex = outside
adrenal medulla = inside
- cortex releases cortisol which stimulates release of glucose
- medulla is responsible for releasing adrenaline or noradrenaline
what are the sex hormones
testes –> testosterone
ovaries –> oestrogen
describe the testes
- release androgens which include testosterone
- testosterone is responsible for development of male sex characteristics during puberty
describe the ovaries
- releases oestrogen which controls regulation of female reproductive system
- eg: menstural cycle or pregnancy
describe the pineal gland
- releases melatonin
- responsable for important bio rythms
eg. sleep-wake cycle
describe the thyroid gland
- produces thyroxine
- stimulates metabolism
what is the fight or flight response
an evolved response which was adaptive during hunter gatherer times
- allowed ppl to either escape stressor or fight an intruder
describe the process of the fight or flight response
1) person enters stressful situation
2) amygdala activates which sends distress signals to hypothalamus
3) hypothalamus activates sympathomedullary pathway
4) SNS stimulates the adrenal medulla
5) AM secretes adrenaline and noradrenaline into blood
6) adrenaline causes number of physiological changes to prepare the body for fight or flight
describe the amygdala
- associates sensory signals with emotions such as fear or anger
- sends ‘distress signals’ to the hypothalamus
describe the hypothalamus in regard to the fight or flight
in response to continued threat, releases CRH into bloodstream
describe the pituitary gland in regards to fight or flight
releases ACTH into bloodstream, and from there to its target sights
describe the SNS in regards to fight or flight
prepared the body for rapid action associated with fight or flight
describe the Parasympathetic NS in regards to to fight or flight
PNS dampens down the stress response when the threat has passes
describe the adrenal medulla in regards to fight or flight
AM releases adrenaline into bloodstream which causes physiological changes to prepare
eg: increased heart rate
describe the adrenal cortex in regards to fight or flight
releases stress hormones, including cortisol, in response to stress
describe the feedback system in regards to fight or flight
cortisol levels are monitored so that CRH and ACTH production is inhibited if cortisol is too high
what are acute stressors
- short term
- have to deal with it immediately
what are chronic stressors
continued receiving of threatening signals over a long period of time
eg: stressful job
what happens in the presence of chronic stressors
hypothalamus activates a stress response system called the HPA axis
(hypothalamic-pituitary-adrenal axis)
describe the HPA response system in regard to chronic stressors
H) hypothalamus releases corticotropin-releasing hormone which stimulates the pituitary gland
P) when CRH arrived in PG it causes the production/release of ACTH which is transported via bloodstream
A) ACTH stimulates the adrenal cortex to release various stress related hormones such as Cortisol
