lecture 3 animals Flashcards
animals have systems that…
percieve and respond to change in their internal and external environments
all perception and response requires what
information flow aka communication
what does information flow include
chemical and or electrical signalling between cells – coordinating responses at cellular, tissue, organ, ad system levels
edocrine and nervouse systems are major..
systems that control responses to stimuli and coordinate body activities and maintain homeostasis
the endocrine and nervous systems are specialized for
different functions – cells invovled in systems look and behave differently
endocrine system - signalling type
hormones
endocrine – transmission
hormones travel through blood
endorcine – speed
fast and slow
fast = adrenaline rush
slow = puberty growth
why is majority of endocrine signalling slow
because it has to go through blood vessel system – not an immediate rewaction
endocrine – duration
short/loing
short = adrenaline rush
long = growth (puberty doesnt happen overnight)
specificity endocrine
achieved by hormone/receptor interaction
lock and key
– specific cells, specific receptor, specific hormone, specific response
nervouse system is composed of
neurons
nervous systep - signal type
electrical impulse and chemical neurotransmitter
nervous system - transmission
neuron
nevous system speed
very fast
nervous system duration
short
specificiy nervous system
achieved by close connection of neurons and target cells (receptor cells)
basic rundown of hormon transmission endorcine sysptem
endocrine cell rescieves stimulus and releases hormones in response – hormones enter blood vessel – travel down blood system – bind to specific receptors on specific target cells – create response to stimulus
nervous system run down transmission
dendrites are projections on neurons that recieve any kind of stimulus – electrical signals are triggered. – tells neurons to produce electrical impulses (with sufficient stimulus to cell body) – impulses are generated and sent down the axon – synaptic terminals release neurotransmitters through synapse (gap between original neuron and next cell) – postsynaptic cell recieves neruotransmitters
neurons definition
cells responsible for generating and transmitting electricochemical impulses of the nervous system
Glia cells
maintain homeostasis, form myelin, nourish, provide support and prottection for neurons in central and peripheral nervous systems
basic units of nervous system
neurons
support cells of nervous system
glia
what are the two parts of the nervous system
central nervous system and peripheral nervous system
CNS
brain and spinal cord
PNS
connects to all your limbs, parts of face ect..
cranial nerves (face)
ganglia outside CNS (neuron cell bodies grouped together)
spinal nerves (bundle of axons)
information processing in the nervous system is composed of how many stages
three stages
sensory, integration, motor
basic rundown of processing information nervous system – use three sytages
- sensory organ (eyes) see something scary – this is the sensory input. – input goes through the pNS and to the CNS (into brain)
- integration – brain will process and integrate information and send signal to diff part of PNS (motor neuron)
- motor output will elicit a specific response (effector – target msucle, cell..)
what about reflexes? give rundown of what haooens
instead of reaching the brain, it just reaches spinal cord (bypasses brain) why you dont think about reflexes
– stimulus – hammer thing to knee cap – sesnory neurons sense muscle getting shorter – sends info to ganglia around the spinal cord – spinal cord process infor very quickly (interneurons) – then sends down to motor neurons which sends info to quadricep and hamstring (quad to contract and ham to relax) – jerking motion
endocrine cells secrete hormones into blood stream affecting what
target cells to regulate physiology and behaviour
major endocrine glands
hypothalamus, adrenal, pituitary, gonads, pancreas, parathyroid, thyroid, pineal
hypothalamus
where verything is controlled in endocrine system - acts as the “master regulator” does work primarily through the pituitary gland
hypothalamus and posterior pituitary are really integrated with each other bc of what cells
neurosecretory cells of the hypothalamus – these are neurons that extend into the posterior from the hypothalamus – part of cell in hypo, and part of cell in post pit (axons of neurosecretory cells are in post pit)
what is a neurosecretory cell (function)
it is a neuron that produces hormones and secretes them directly into the bloodstream – functional overlap between nervous system and endocrine (hormones (end) + neurons (nerv)
rundown of transmission from hypothalamus to post pit
neurosecretory cells produce hormons – neurohormone runs down acxon into post pit – through synapse – and distributed into blood vessel for transmission around body
what is the anterior pituitary made up of
endocrine cells that respond to hormones from hypothalamus by secreting their own hormones
hypothalamus –> anterior pit
neurosecretory cells end just about ant pit. neurohoromones travel through portal vessels to ant pit – as a response ant pit produces its own hormones that will be released into the blood stream .
hormones into the bloood stream will reach other glands to..
regulate the function of other endocrine glands
what is short-term stress response
fight or flight – involves both nervous and endocrine system
what c ontrols connection between endocrine and nervous system
hypothalamus
in the case of fight or flight – the hypothalamus affects endocrine..
without acting through pituitary gland – instead it does so via the spinal cord – to adrenal glands ontop of kidneys
basic response to figth or flight
hypothalamus recieves stress information – nerve cell directly relays info to spinal cord - spinal cord seends message directly to adrenal glas, and adrenal gland will secrete hormone called adrenaline – specifically in form of epinephrine and norepinephrine
hormone (adrenaline) effects include:
- increased heart rate
- increased breathing rate
- increased metabolic rate
- increased blood glucose
- change in blood flow pattern (more blood flow in muscles, legsa.. than digestive to fight back or run
how hormones react depends on what two things
structure and solubility
we have water-soluble hormones (hydrophilic) – dont need help travelling through fluid (blood, insulin)
lipid-soluble hormones (hydrophobic) – need help travelling through fluid system (cortisol)
pathway of water-soluble hormones
water soluble hormones are stored in vacuoles because they cannot pass the phospholipid membrane alone – because stored, these hormones can be made in advance – the way the get released is through exocytosis – where the vacuole fuses with membrane and releases the hormones – hormone will travel through blood easily (water loving) – after travel through blood, with help of signal receptor protein hormone will bind to specific ereceptor (lock and key) to travel through the membrane to the receptor/target cell – will need transportation to enter nucleus for gene regulation, or will go straight to cytoplasm for response (cytoplasmic response)
pathway of lipid-soluble hormones
lipid soluble hormones are only made when needed bc theyre not stored – they easily pass through phospholipid membrane – but need help from transport protein to move through blood – ones traveled through blood passes straight through membrane no problem – and goes straight through nucleus where the receptor is – Most if not all lipid soluble hormones effect gene regulation – proteins from regulation released into cytoplasm for response.
a single hormone can produce..
different effects in different cells
the response of a target cell to a hormone depends on
the signalling pathways qwithin target cell
the type of receptor on target cell
same recepotor but diff cell example
response to fight or flight
hormone is epinephrine (adrenaline)
one cell = liver
receptor = beta receptor
when epinephrine binds to B receptor on liver, glycogen is stored in liver, but when hormone binds – signals for glycogen to break down into glucose and releqase it from cell into bloodsteream (need that glucose energy)
second cell = skeletal musclec blood vessel
same receptor
when hormone binds, it allows vessel to dilate to allow more / faster blood flow in respoinse to fight or flight
different receptor same cell
we know that muscular blood vessel – epinephrine with B receptor allows vessel to dilate – allowing more enrgy to skeletal muscles
but second receptor (A) on intestinal blood vessel - when binds - vessil constricts – limiting blood flow – diverts blood for digestive to allow blood to be directed to parts where it is needed during fight or flight
endocrine systems use what hormones to maintain homeostasis
antagonistic hormones
what are antagonistic hormones
pairs of hormones whose actions oppose each other
– maintain physiological parameter within acceptable range
example of antagonisatic hormones
insulin and glucagon are antagonistic hormones that regulate blood glucose concentration
negative feed back when too much blood sugar in system
homeostasis blood sugar levels around 70-110 mg/100ml of blood
stimulus – you had large bowl of pasta – blood glucose levels increase!
– pancrease gets this signal and beta cells of pancrease release insulin into the blood
– insulin tells body cells to take up more glucose and also tells liver cells to store glucose as glycogen -
– this makes blood levels decline and return to homeostasis
negative feedback when too little blood sugar in sysatem
at homeostasis – say you skipped a meal
– stimulus is that there is too little blood glucose level
– pancrease gets this stimulus and its alpha cells release glucagon into the blood
– glucagon tells liver to break down glycogen to glucose and release it into the blood
– this increases levels ands returns back to homeostasis
