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What does the somatic nervous system do?
Conscious thinking
What does the autonomic nervous system do?
Subconscious thinking
What are the two branches of the autonomic nervous system?
Sympathetic and parasympathetic
Is the autonomic motor, sensory, or both?
Motor
What does the axon hillock do?
Recieves all information and determines if an AP is sent
What doe the axon do?
Carries information
What do dendrites do?
Receive information
What is the charge inside of the cell typically?
Negative
What is the charge outside of the cell typically?
Positive
Why are the inside and outside of the cell charged differently?
If they were neutral then ions wouldn’t flow
How do voltage gated ion channels open/close?
Changes in electrical charge
How do ligand gated ion channels open?
Hormones or neurotransmitters bind to receptors opening the gates
How do ligand gated ion channels close?
Something removes hormone or neurotransmitter from receptor
How do tension/mechanical gated ion channels open?
They are physically pulled open
What is an example of a mechanical gated ion channel?
The stretch reflex
What happens when something depolarizes?
It becomes more positive
What happens when something hyperpolarizes?
It becomes more negative
Where do most APs usually form?
Axon body
When is a time that an AP wouldn’t form at the axon body and instead form at the center of a neuron?
Hitting your funny bone
What is a graded potential?
A slight change in charge
What can you do with one action potential?
Muscle twitch
What do multiple graded potentials sum into?
1 action potential
What happens to voltage gated ion channels when an action potential is sent?
They open
During the Na/K pump what is it trying to kick out of the cell membrane?
K
What is the refractory period?
It prevents back to back action potentials
What kind of axons are the fastest?
Large diameter and myelinated
How fast does an AP send in a fast axon?
100 meters per second
What kind of axons are the slowest?
Small diameter and unmyelinated
What kind of receptors would have slow axons?
Pain receptors
What is an example of a slow pain receptor?
Time between stubbing your toe and feeling the pain
How fast do slow axons send APs?
2 meters per second
What happens when sodium enters at the synaptic cleft?
The cell gets excited
What happens when chlorine enters at the synaptic cleft?
The cell get inhibited
What happens to receptors when sodium or chlorine enters the cell?
Open or close
If someone has a condition like tourettes where their brain has trouble constantly inhibiting their thoughts what may be occuring at the cell level?
They may have excess sodium or insufficient chlorine
Why do ion channels close quickly?
Neurotransmitters and hormones don’t last long
When are motor neurons excitatory?
Always
How does skeletal muscle get innervated?
A nerve touches each muscle fiber
When can neurons pass fiber to fiber in muscle tissue?
In cardiac and smooth muscle
What are the positives of drugs that block Na?
Nothing happens once threshold is reached
What is an example when a Na blocking drug may be used?
Novacaine at the dentist blocking pain APs
What occurs when muscle relaxants are used?
Excitability is decreased at the neuromuscular junction
What occurs when antispasmodics are used on chronically activated muscles?
Decrease excitability of CNS
What occurs in someone who has multiple sclerosis?
Decreased myelinated motor pathways slow down sensory information to brain making it harder to readjust to new enviornments
Who was Jimmie Heuga?
Olympic skier that was told to stop exercising to slow his M.S., but after restarting exercising actually got better
What happens during myasthenia gravis?
The body creates antibodies that bind to ACh receptors and block ACh decreasing ability to control muscle
What kinds of muscles tend to be affected by myasthenia gravis first?
Weakest muscles, usually eyelids
What happens during botox?
ACh receptors are blocked preventing contractions and wrinkles
What does curare do?
Blocks ACh receptors
What does frog poison do?
Blocks voltage gated Ca channels
Where is the motor cortex of the brain?
Precentral gyri
Where is the sensory cortex of the brain?
Post central gyri
What does the frontal lobe do?
Complex reason and conceptual ideas
Why is there less space on the homunculus for larger muscles?
They do gross motor movement and don’t do as many refined actions
Why is there more space on the homunculus for smaller muscles?
Things like the hands and tongue require fine motor movement
What are the neurotransmitters of the autonomic nervous system?
Norepinephrine and acetylcholine
What binds to cholinergic receptors?
Acetylcholine
What are the two kinds of cholinergic receptors?
Muscarinic and nicotinic
Is muscarinic typically inhibitory or excitatory?
Inhibitory
Is nicotinic typically inhibitory or excitatory?
Always excitatory
What binds to adrenergic receptors?
Epinephrine/adrenaline
What are some catecholamines?
Norepinephrine, epinephrine, and dopamine
What is the typical route for APs traveling?
Preganglion → interneuron → postganglion
Does the PNS typically have short or long preganglionic?
Long
Does the PNS have local ganglia or more system wide?
Local, close to effector
Does the SNS typically have short or long preganglionic?
Short
Does SNS have more widespread or local ganglions?
Widespread
Where does the PNS exit?
Vagus nerve
Where does the SNS exit?
Thoracic/lumbar spine
What kind of receptors are preganglia?
Nicotinic
Why are preganglionic nicotnic?
They have to be excitatory to activate post ganglionic
What kind of receptors are on parasympathetic postganglionic?
Cholinergic
Why is the parasympathetic postganglionic made up of cholinergic receptors?
Allows for nicotinic and muscarinic so you can have inhibitory and excitatory effects
What kind of receptors are on sympathetic post ganglionic?
Adrenergic
Why are sympathetic post ganglionic receptors adrenergic?
Sympathetic is almost always excitatory
What is the exception to the preganglionic → interneuron → postganglionic trend?
The adrenal medulla acts as the preganglia and then release epi and norepi
What are the main types of sensory receptors?
Mechanoreceptors, thermoreceptors, nociceptors, chemoreceptors, photoreceptors
What are two types of mechanoreceptors?
Muscle spindles and GTO
Where are the two main types of thermoreceptors in the body?
Skin and hypothalamus
What is the point of thermoreceptors?
They tell the brain what could happen if in hot/cold for too long
What is an example of the brain saying what could happen when it comes to thermoreceptors?
Jumping into a cold pool will resolve fast, being in the Antarctic sea is detrimental to health
Where are the most sensitive thermoreceptors?
Hypothalamus
What are nociceptors?
Pain receptors, nerve endings
What do chemoreceptors do?
Detect gas or lack of it in the blood
What do chemoreceptors do in muscles?
Detect lactate and phosphate and open arteries to increase blood flow
Do sensory neurons go into the body anteriorly or posteriorly?
Posterior
Do motor neurons go out of the body anteriorly or posteriorly?
Anterior
Where are neurons inhibited?
At the spine
What does the cerebellum do?
Brings in sensory info and helps with automated and complex movements
What type of movements does the cerebellum help with?
Typing, walking
If the cerebellum was injured what could happen?
More erratic movement
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