nervous system part 2 Flashcards
what are the 5 groups of neurotransmitters
acetyl choline
gases - e.g. nitric oxide
amino acids - e.g. glutamate
biogenic amines - synthesised from amino acids e.g. norepinephrine, serotonin
neuropeptides - short chains of amino acids e.g. endorphins
name some nervous system disorders
schizophrenia
depression
Alzheimer’s disease
Parkinson’s disease
what is Parkinson’s disease
a nervous system disorder that is more common with advancing age
symptoms include difficulty initiating movement, stiffness, muscle tremors, and poor balance
it is caused by death of neurons in the midbrain which normally release dopamine
what is a neurotransmitter
a molecule that is released at the synaptic terminal of a neuron at the chemical synapse, diffuses across the synaptic cleft and binds to the postsynaptic cell, triggering a response
what is depression
a nervous system disorder characterized by a depressed mood, abnormalities in sleep, appetite and energy levels
there are two types - bipolar disorder and major depressive disorder
results from lack of
it is caused by lack of activity of biogenic amine neurotransmitters
fluoxetine can be used as a treatment - selective serotonin reuptake inhibitor
what are SSRIs and what is their role as antidepressants
selective serotonin reuptake inhibitor - they increase the extracellular level of the neurotransmitter serotonin by limiting its reabsorption (reuptake) into the presynaptic cell, increasing the level of serotonin in the synaptic cleft available to bind to the postsynaptic receptor
what is the role of dopamine
attention, problem-solving, and memory and enjoyment
what is the role of serotonin (biogenic amine)
an inhibitory neurotransmitter, meaning that it doesn’t give the next neuron the signal to fire. Serotonin is involved with mood, as well as your sleep cycle
what is the role of GABA (biogenic amine - made from glutamate amino acids)
an inhibitory neurotransmitter that helps to balance any neurons that might be over-firing. helpful with anxiety or fear because the release of GABA helps to calm you down. involved in vision and motor control
what is the function of norepinephrine and epinephrine (made from amino acids - biogenic amines)
excitatory neurotransmitter that helps to activate the sympathetic nervous system, which is your “fight or flight” response to a stressor.
what do pleasure drugs do to the reward system
they enhance it
give examples of pleasure drugs that act on the reward system
cocaine, heroin, amphetamine, alcohol and tobacco
do most pleasure drugs affect ore than one neurotransmitter
yes e.g. alcohol affects Dopamine, GABA, endorphin, glutamate…….
how does cocaine affect the reward system
it floods the synaptic cleft with dopamine and block removal
the body then responds with negative feedback resulting in
- reduced dopamine release
- reduced receptor density
- reduced metabolism of brain areas
which contribute to withdrawal syndrome
what are the cell that have a receptor for a hormone called
target cells
which organ system is responsible for chemical signalling by hormones
the endocrine system
which 2 organ systems tend to overlap in control of chemical signalling
endocrine and nervous system
what are the steps in endocrine signalling
hormones are secreted into extracellular fluid by endocrine cells
the hormones reach the target cells via the bloodstream
what are the main functions of endocrine signalling
to maintain homeostasis
to mediate responses to environmental stimuli
regulation of growth and development
triggers physical/behavioural changes underlying sexual maturity and reproduction
what are the 3 major chemical classes of hormones
polypeptides
steroids
amines
what type of hormone is insulin
polypeptide
what type of hormone is cortisol
steroids
what type of hormones are epinephrine and thyroxine
amines
how do water soluble and lipid soluble hormones differ
location of receptor proteins in target cells:
- water soluble hormones travel freely in the bloodstream
- water soluble hormones can’t diffuse through target cell membranes so the receptors are on the cell surface (they sometimes alter gene transcription)
- lipid soluble hormones bind to transport proteins to keep them soluble in the blood
- lipid soluble hormones diffuse into target cells and bind too receptors in the cytoplasm or nucleus (it changes gene transcription)
are thyroxine and steroid hormones water soluble or fat soluble
fat soluble (hydrophobic)
are peptide hormones ad neurotransmitters fat soluble or water soluble
water soluble (hydrophilic)
what different response can result from a water soluble hormone binding to a cell surface receptor
activation of an enzyme
change in uptake/secretion of specific molecules
rearrangement of the cytoskeleton
receptors can cause proteins to move into the nucleus and alter transcription
what is signal transduction
the conversion of an extracellular signal into an intracellular response
what is the signal transduction response to short term stress
when in a stressful situation, the adrenal glands on top of the kidneys release epinephrine (adrenaline)
epinephrine binds to a G protein coupled receptor in the plasma membrane of target cells
this triggers a cascade of reactions involving synthesis of cAMP
cAMP activates kinase production which breaks down glycogen and inactivates glycogen synthesis enzymes
the liver releases glucose providing the body with extra fuel
what is the signal transduction response to steroid hormones
most steroid hormone receptors are in the cytosol
binding of a hormone to the receptor forms a complex that moves into the nucleus
the receptor part of the complex alters transcription of particular genes
some endocrine cells are found in organs that are not part of the endocrine system. give an example
the stomach contains isolated endocrine cells that help regulate digestive processes by secreting the hormone gastrin
what are the ductless organs called where endocrine cells are grouped
endocrine glands e.g. thyroid glands
what is the difference between endocrine glands and exocrine glands
endocrine glands secrete hormones directly into the surrounding fluid
exocrine glands have ducts that carry the secreted substances such as sweat or saliva onto body surfaces or into body cavities
name the human endocrine glands
thyroid parathyroid adrenal ovaries testes hypothalamus pituitary pancreas
what are the steps in a simple endocrine pathway (negative feedback)
endocrine cells respond to a stimulus by secreting hormones
hormone travels in the blood stream to target cells where it interacts with receptors
signal transduction brings about a physiological response
e.g. secretin to neutralise chyme
what are the steps in a simple neuroendocrine pathway (positive feedback)
stimulus received by a sensory neuron rather than an endocrine tissue
the sensory neuron secretes a neurosecretory cell
the neurosecretory cell secretes a neurohormone which diffuses into the blood stream and travels to target cells
e.g. oxytocin in suckling
where are hormones released by the posterior pituitary made
the hypothalamus
where are hormones releases by the anterior pituitary made
the anterior pituitary (makes and produces under regulation of the hypothalamus)
in negative feedback, the response ……….. the initial stimulus
reduces - it helps restore a pre-existing state
in positive feedback, the response ………… the initial stimulus
enhances
what are the 2 posterior pituitary hormones
ADH and oxytocin - they are made in the hypothalamus and stored in the posterior pituitary to be realised n response to nerve impulses from the hypothalamus
hormones released by the hypothalamus trigger the release of ……………… pituitary hormones
anterior
what are the 2 types of stress
rapid - fight or flight
long term - if beyond homeostatic control
what are responses to rapid stress
liver breaks down glycogen to supply glucose
epinephrine is released into the blood
heart beats faster and stronger - blood pressure rises
fat cells release fatty acids into the blood
blood vessels to gut and skin constrict while more blood flows to the escape muscles
………. is produced by the hypothalamus and ………… released by the posterior pituitary in response to long term stress. the adrenal glands then produce …………
CRH
ACTH
cortisol
what are the actions of cortisol
- Supresses immune response
- Increases glucogenesis
- Diverts energy to the CNS
- Inhibits insulin production
what is a circadian cycle
a daily cycle
what is chronobiology
systematic study of adaptations to cope with regular geophysical cycles
what is chronotype
a person’s natural inclination with regard to the times of day when they prefer to sleep or when they are most alert or energetic.
if you find it easy to wake up is your circadian rhythm long or short
short
if you find it hard to wake up is your circadian rhythm long or short
long
what is social jetlag
when the biological clock is out of sync
what do body clocks coordinate with
environment keys e.g. sunlight, mealtimes
what can an annual or seasonal change in the body clock be a result of
hibernation, aestivation, reproduction, migration
