Homeostasis Flashcards
What is a negative feedback control
-aims to maintain a controlled variable at its set point
-a controlled variable is an aspect of the internal environment eg temperature or blood pH
-the set point is the value at which the variable should be manipulated
-homeostasis is regulated by nervous system and endocrine system
What is the positive feedback control
-initial stimulus promotes a response which is self reinforcing
-blood clotting eg
Damage to blood cell> activation of clotting factors>activation of thrombin>formation of blood clots
Describe ganglia and nuclei
-a ganglion is a location where neruones synapse in the peripheral nervous system
-usually the place where the cell body of one of the neurone synapsing is located
-action potential in the presynaptic neurone leads to the release of a neurotransmitter
-neurotransmitter leads to the invitation of an action potential in post synaptic neurone
Describe motor nerves
-pathway consists of upper and lower motor neurones
-UMN within central nervous system
-UMN synapses with LMN at the nucleus in central nervous system
-LMN leaves central nervous system and passes into peripheral system
-LMN innervates target issue
-Single LMN in somatic motor neruones
-Paired LMNS in autonomic motor neurones
What is the sympathetic nervous system
-fight or flight
-increased heart rate and pulse
-peripheral vasoconstriction
-pupil dilation
-sweating
What is is parasympathetic nervous system
-rest and digest
-decreased heart rate and pulse
-bronchiole constriction
-pupil constriction
What is the autonomic nervous system (ANS)
-both sympathetic and parasympathetic divisons innervate most organs and tissues
-often have opposing effects
-sympathetic more active in stressful situations
-parasympathetic more active in vegetative situations
What is the endorcrine system
-some hormones are secreted by endocrine glands into circulatory system
-others by endocrine cells scattered amongst other tissues
What are adrenal glands
-medulla of glands contained modified postganglionic sympathetic neruones
-produce noradrenaline and adrenaline
-produces a similar effect to other sympathetic responses but longer lasting
-sympathetic neurones stimulate adrenal medulla
Nervous system vs endocrine system
N- fast because of nerve conduction
N-effects are brief
N-targeted by nerve pathway and neurotransmitter receptors
E-uses hormones
E- reaches every tissue
E- prolonged effects
E-targeted by location of hormone receptors
What does the autonomic system do
Component of the peripheral nervous system that regulates involuntary processes
Peripheral nervous system
Part of your nervous system that lies outside your brain and spinal cord. Plays a key role in both sending information from different areas of your body to your brain as well as carrying out commands from brain to various parts of your body
