Anatomy lecture exam 4

how do nicotinic receptors work?

• Stimulated by nicotine

• Found on motor end plates between first and second autonomic neuron, and in parts of CNS

• Both a Sodium and potassium ion channel (ION GATED)

• More sodium enters than potassium leaves

• Weak EPSP

how do muscarinic receptors work?

• Stimulated by muscarine

• Found in CNS and parasympathetic targets (smooth/cardiac muscles and glands)

• Requires G-proteins to open channels

• Binding of acetylcholine opens K+ channels in some tissues (IPSP) or
  closes K+ channels in others (weak EPSP)

are nicotinic receptors excitatory or inhibitory?

Excitatory

are muscarinic receptors excitatory or inhibitory?

Both:

• Potassium out = Inhibitory

• Potassium in = Excitatory

what does acetylcholinesterase do?

Breaks down acetylcholine in synapses, allowing instant termination of a response

how do monoamine receptors work?

• Uses a secondary messenger, most commonly cAMP

• Most are excitatory

• Different types of receptors for each monoamine

what does monoamine oxidase do?

Breaks down monoamines in presynaptic cell

what are monoamine oxidase inhibitors?

Drugs that block monoamine oxidase, enhancing the action of all 4 monoamines by increasing amount released

what is reuptake?

The process of taking monoamines back into the presynaptic cell through reuptake proteins

Where are serotonin receptors found?

Idk, but its secreted by the brain stem

What is serotonin associated with?

Elevated mood, alertness, appetite

How do SSRIs work?

Bind to serotonin receptors to prevent the reuptake of serotonin

What diseases are related to serotonin?

depression and eating disorders

Where do you find dopamine receptors?

Forebrain and midbrain

what functions is dopamine associated with?

Emotional reward and addiction

what causes Parkinson's and schizophrenia?

Too much dopamine

where is norepinephrine used?

Neurons in CNS associated with alertness

what functions is norepinephrine associated with?

excitatory or inhibitory for smooth and cardiac muscle

What do amphetamines do?

Increases alertness, reduces fatigue, depresses appetite

How does cocaine affect monoamines?

blocks the reuptake of all monoamines

Where is glutamate used?

Used in brain for memory storage (most important)

How do glutamate receptors work?

2 kinds:

• AMPA - Uses sodium ion channels

• NMDA - Uses sodium and calcium ion channels

Where is glycine used?

In spinal cord for regulating skeletal muscle movement (makes antagonistic muscles relax like diaphragm)

How do glycine receptors work?

opens Cl- channels when glycine binds to its receptor, making it harder for neuron to reach threshold

Where is GABA used?

In cerebrum for for motor control (most common)

How do GABA receptors work?

• The receptor is also a Cl- ion channel

• Opening Cl- channels hyperpolarizes, making it harder for neuron to reach threshold

Is glutamate excitatory or inhibitory?

Excitatory

Is GABA excitatory or inhibitory?

Inhibitory

Is Glycine excitatory or inhibitory?

Inhibitory

Why does strychnine kill you?

Blocks glycine receptors, preventing you from breathing out

what is Huntington's disease?

Degeneration of GABA-secreting neurons

how do benzodiazepines work?

Enhance GABA’s ability to bind to its receptor

what are benzodiazepines used for?

To relax muscles, sedate, decrease anxiety, & as an anticonvulsant for epileptics

what are the specific neuropeptides mentioned?

Substance P, Neuropeptide Y, Endogenous opioids (Endorphins)

where is substance P found?

Brain and spinal cord

what does substance P do?

Relays sensation of pain

where is neuropeptide Y found?

Brain, spinal cord, and peripheral nervous system.

what does neuropeptide Y do?

Plays a role in stress responses, sleep cycles, cardiovascular control, and appetite stimulation

where are endogenous opioids (endorphins) found?

brain

What do endogenous opioids (endorphins) do?

Blocks prolonged pain transmission and causes euphoria

what two ways do endogenous opioids (endorphins) block pain?

• 1 (post-synaptic): blocks glutamate by blocking calcium ion channels and opening potassium ion channels in presynaptic neuron

• 2 (pre-synaptic): Blocks secretion of substance P by blocking voltage-gated calcium channels

what are endocannabinoids made of?

Lipids

how do endocannabinoids work?

Secreted by dendrites or soma, and can cross the phospholipid bilayer

what makes endocannabinoids retrograde neurotransmitters?

Flow backwards from postsynaptic neuron to inhibit presynaptic neuron.

what is nitric oxide?

A gas produced by some neurons in the CNS and PNS

how does nitric oxide work in brain?

Flows across plasma membrane/phospholipid bilayer in brain as a retrograde NT

what does nitric oxide do in PNS ?

Acts on the parasympathetic neurons like smooth muscle in respiratory tract and blood vessels and makes them relax

is acetylcholine excitatory or inhibitory?

Both depending on which ion channels are open

names of two acetylcholine receptors

Nicotinic and muscarinic receptors

where is acetylcholine used?

Parasympathetic and autonomic neurons of the CNS, and motor end plate of muscle cells

Drugs that bind to acetylcholine receptors

Nicotine, muscarine, and AChE inhibitors

is serotonin excitatory or inhibitory?

excitatory

where is serotonin used

Brainstem

what is the method of reuptake for serotonin?

Reabsorbed through reuptake proteins and broken down by monoamine oxidase

drugs that bind to serotonin

SSRIs (Prozac, Paxil, Zoloft, Lexapro)

Is dopamine excitatory or inhibitory?

Mostly excitatory

how do serotonin receptors work?

Most open sodium or calcium channels.

Where is dopamine used?

Forebrain and midbrain

Dopamine method of reuptake breakdown

Reabsorbed through reuptake proteins and broken down by monoamine oxidase

drugs that bind to dopamine

MAOIs

is norepinephrine excitatory or inhibitory?

Both

where is norepinephrine used?

CNS neurons for alertness, PNS sympathetic neurons

norepinephrine method of reuptake/breakdown

Reabsorbed through reuptake proteins and broken down by monoamine oxidase

three types of glutamate receptors

• AMPA

• NMDA

• Kainate

how do glutamate AMPA receptors work?

Sodium ion channels

How do glutamate NMDA receptors work?

Sodium and calcium ion channels

drug that binds to glutamate

Alcohol

what drugs bind to GABA?

Benzodiazepines, alcohol, and barbiturates

Benzodiazepine examples

Xanax, Valium, Paxil, Lunesta, and Ambien.

what drug binds to glycine?

Strychnine

are endocannabinoids excitatory or inhibitory?

Inhibitory

drug that binds to endocannabinoids

THC

what drug binds to nitric oxide

Viagra

what do amphetamines treat?

Increases alertness, reduces fatigue, depresses appetite, and treats ADHD.

how do amphetamines work in the brain?

Blocks norepinephrine and dopamine reuptake, and reduces MAO activity

what do MAOIs treat?

Parkinson's disease

how do MAOIs work in the brain?

Inhibits monoamine oxidase.

what do SSRIs treat?

Depression

how do SSRIs work in the brain?

Inhibits serotonin-specific reuptake proteins.

what does cocaine do?

Increases alertness, euphoria, heart rate, and sympathetic response.

how does cocaine work?

Blocks the reuptake of all monoamines.

what do benzodiazepines do?

Relaxes muscles, sedates, decreases anxiety, and acts as an anticonvulsant.

how do benzodiazepines work?

Enhances GABA's ability to bind to its receptor.

what are the meninges?

Connective tissue layers that cushion/protect the brain and blood vessels

what are the ventricles?

Fluid-filled chambers that cushion the brain

what is the arachnoid mater made of?

Simple squamous epithelium

what is the dura mater made of?

Dense irregular connective tissue

Mater layers in order from out to in

Dura mater, arachnoid mater, pia mater.

what are the four ventricles of the brain?

Lateral ventricles, third ventricles, fourth ventricles, and central canal.

where are the lateral ventricles found?

Along the length of the brain in either hemisphere

where is the third ventricle found?

Towards the core of the brain

where is the fourth ventricle found?

Around the cerebellum

where is the central canal found?

In brainstem and spinal cord

what does cerebrospinal fluid do

Reduces brain weight and cushions it, as well as transporting nutrients and waste.

what is white matter?

Tracts of axons

what is gray matter?

Region where synapses are

What are the gyrus?

Raised worm-like structures on the brain

what are the sulcus?

Grooves covering the exterior of the brain

how do the two cerebrums communicate?

Through the corpus callosum

what is an aphasia?

Speech problem