Module 2D (Pt1) Flashcards
What is heart contractual function under
- Rhythmic control from the SA node
What is the rhythmic contraction from the SA node mediated by
- Mediated by calcium
What is depolarization
- When the action potential occurs
- Allows for positive ions in cell and negative ions out of the cell
During depolarization what ions go in and out of the neuron
- Potassium ions into the neuron and sodium ions out of the neuron
What is myelin
- Neurons coated with it
- improves productivity to allow for the signals to jump from one gap to another
- Allows for the action potential to move much faster and not reduce
- improves productivity to allow for the signals to jump from one gap to another
What is a neuron
- The major cell type of the nervous system
- An excitable cell that processes and transmits information through chemical or electrical signals
What are ganglia (ganglion is single)
- Structure containing multiple neuron cell bodies linked by synapses
What is the synapse
- Meeting of two neurons
- Presynaptic receives an action potential (at the end of the neuron it is calcium that
Causes the response rather then sodium)
- Presynaptic neuron causes a response in the post and after this occurs the mediators
Are then re uptake or absorbed into the pre
What are the two parts of the autonomic nervous system
- Sympathetic
- Parasympathetic
What division is the autonomic nervous system part of
- Peripheral-> motor-> autonomic
What is the autonomic nervous system
- The part of the peripheral nervous system that regulates automatic functions of the body that occur without conscious control
- Distributed throughout the body
What does the ANS innervate
- Heart, blood vessels, glands, viscera, smooth muscle in some tissues
What is the ANS made up of
- Nerves, ganglia, plexuses
What is the fight/ flight pathway
Sympathetic
What is the rest/ digest system (slow down)
Parasympathetic
4 main things the autonomic nervous system does
- Changes in stomach secretions
- Changing heart rate
- Redistributing blood
- Effecting body temp
What is a nerve
- The major cell type of the nervous system
- An excitable cell that processes and transmits information through chemical or electrical signals
What is a plexus
- A branch network of interconnecting nerves
What type of system is it SNS
Thoracolumbar system
Pre vs post ganglionic axon length in SNS
- Pre: short (distance between spinal column and synapse)
- Post long
Is the Sympathetic nervous system coordination
- Yes it is
- Does this as there are many long post ganglionic axons that come from a single short pre ganglionic axon
During a moment of stress what are the responses in the Sympathetic nervous system
a) Signal is moved along efferent nerves of the brain and pre ganglionic neuron to the ganglion
b) At ganglion the pre ganglionic neurons release Acetylcholine into synapses
c) This stimulates an action potential in the post ganglionic neurons
d) Signal is moved along post ganglionic neurons to effector organ
e) At the effector organ the post ganglionic neurons release norepinephrine which causes a response through a receptor
What type of neurotransmitter(s) does the sympathetic nervous system use
- The pre ganglionic neurons release acetylcholine
- The post ganglionic neurons release norepinephrine
When the sympathetic nervous system is activated what responses occur
- Pupils dilate (mydriasis)
- Salivary glands inhibited
- Heart rate increase
- Breath rate increase
- Blood is directed to the heart lungs, and skeletal muscle
- Blood is directed away from stomach, intestines and sex organs
- Piloerection (hairs stand on end) not seen as much in humans as other animals
What type of system is the PNS
- Craniosacral system
Pre vs post ganglionic axon length in PNS
- Pre ganglionic axons are long
- Post ganglionic axons are short
Where are ganglia located in relation to spinal column in PNS
- Far away from the spinal column
Is the PNS coordinated
- No it is not as it is around a 1:1 ratio between pre and post ganglionic axons
- This is as it is not worried about a rapid coordinated response but rather just want to get the job done
When is the PNS activated
- In the absence of stress
What type of neurotransmitter(s) does the PNS use
- At both the pre and post ganglionic neurons ACh is released
When the parasympathetic nervous system is activated in the absence of stress what occurs
a) Signal is moved along efferent nerves of the brain and pre ganglionic neuron to the neuron
b) At the ganglion the pre ganglionic neurons release Ach into the synapses
c) This stimulates action potentials in the post ganglionic neurons
d) Signal is moved along post ganglionic neuron to effector organ
e) At the effector organ the post ganglionic neuron releases Ach and causes a response at receptor
When the PNS is activated what occurs
- Pupils constrict (miosis)
- Salivary glands are activated
- Heart rate decreases
- Breath rate descreases
- Digestion and peristalsis increase (blood flow increases to gut)
- Blood increases to the sex organs
Does PNS or SNS have a higher ratio of ganglionic cells to pre ganglionic neurons and why
- The SNS has a higher ratio as its sympathetic fibers branch and allows its terminals to contract large number of postganglionic neurons
- This is done to allow for a coordinated response
a) The SNS has a ratio of pre ganglionic neurons to ganglionic cells of >1:20
b) The PNS has a ratio about 1:1 with exceptions
- This is done to allow for a coordinated response
