Lecture 25

cells within the nervous system that transmit information to other nerve cells, muscle cells, or gland cells

neuron

each neuron consist of what

cell body, dendrite, and an axon

what are axons covered in

a myelin sheath which accelerates the trasmission of electrical signals along the axon

phospholipids

hydrolyzable lipids that contain a phosphorus (P) atom

two common types of phosphorus (P)

phosphoacylglycerols and sphingomyelins

myelin Sheath is rich in

Sphingomyelins

deterioration of the myelin sheath is seen in

multiple sclerosis and leads to disabling neurological disorders

without myelin sheath

normal nerve trasmission is disrupted causing numbness, blindness, speech disorders, and tremors

space between two neurons

synapse

where are neurotransmitter stored in

small packets called vesicles near the synapse

this triggers the release of the neurotransmitter from vesicles into the synapse

presynaptic neuron

contains the receptors that bind the neurotransmitter

postsynaptic neuron

once the neurotransmitter is bound to the receptor

the chemical message is delivered

\-the neurotransmitter is then degraded or returned to the presynaptic neuron to begin the process again

all Neurotransmitter contain

Nitrogen atom

three important neurotransmitter are

amines (Norepinephrine, Dopamine, and Serotonin) and one is ammonium ion (acetycoline)

two structurally related neurotransmitter that are both synthesized from the amino acid

norepinephrine and domaine

Norepinephrine (Nothing crazy)

above normal: individual feels elated

very high: manic behavior

when is norepinephrine converted to epinephrine

when an individual experiences fear or stress

dopamine

affect the brain processes that control movement, emotions, and pleasure

dopamine plays a role in

addiction

what happens when dopamine producing cells die and there is too little dopamine in the brain

Parkinson’s disease- individual loses control of fine motor skills

what is special about dopamin

it cannot be directly taken by a patient because it cannot cross the blood brain barrier

L-Dopa

a dopamine precursor, is used to help treat the dopamine deficient brains of Parkinson’s patients

when cross the barrier into the brain it is converted into dopamine

overly high levels of dopamine

are unhealthy and associated with schizophrenia

schizophrenia

serious mental illness that affects how a persons thinks, feels, and behaves

people with schizophrenia

may seem like they have lost touch with reality, which causes significant distress for the individual, their family members, and friends

plays an important role in addiction

dopamin

drugs such as heroin, cocaine, and alcohol

increase dopamine levels and give a sensation of pleasure

when dopamine receptors are over-stimualted

they decrease in number and sensitivity; thus why a person needs to take more to feel same “high”

hormone made from norepinephrine

epinephrine

epinephrine release causes

increase HR

increase BP

increase glucose synthesis

dilation of lung passages

danger or emotional stress causes the formation of

epinephrine; body metabolizes stored carbs to form glucose which provides an energy boost

effect of epinephrine know as

“rush of adrenaline” or “flight or fight”

synthesize from the amino acid tryptophan

serotonin

serotonin is an important regulator of

mood, sleep, perception, and temperature regulation

deficiency of serotonin causes

depression, so many antidepressant drugs are selective serotonin reuptake inhibitors (SSRI)

selective serotonin reuptake inhibitors (SSRI)

inhibit the reuptake of serotonin by the presynaptic neuron, effectually increasing its concentration

fluoxetine (Prozac) is a common

SRRI antidepressant medication

IMPROPER levels of serotonin can also cause

migraine headaches

migraine

a type of headache

\-symptoms such as nausea, vomiting, or sensitivity to light and sound (one side of the head)

medication that is prescribed to alleviate migraine symptoms

sumatriptan

serotonin syndrome

when your body has too much of the chemical serotonin

serotonin syndrome

\-changes to mental state

\-dry mouth

\-sweating or fever

\-hyperthermia and shock

\-diarrhea or nausea

\-tremors or reflex changes

\-muscle rigidity

serves as a neurotransmitter between neurons and muscle cells

acetylcholine

at low concentrations

nicotine binds to acetylcholine receptor, resulting in feelings of well-being and alertness

\-this tiggers other nerve cells to release dopamine (which increases pleasure sensation)

as the dopamine receptor deplete over time

a person will crave more nicotine to reproduce the “high” feelings

biologically active amine formed in many tissues

histamine

histamine is a neurotransmitter with two different receptors

H1 and H2 with a wide range of effect on the body

where is histamine produced

mast cell

effects of histamine (GENERAL)

gastric acid secretion

blood vessels to dilate

contraction of respiratory ways

itchiness

H1 receptor

dilates capillaries (vasodilators)

symptoms of allergies sneezing, itching, hives, and water eyes

common antihistamines block

histamine uptake by binding to the H1 receptor; this prevents vasodilation, easing cold and allergy symptoms but can cause DROWSINESS

newer antihistmines

cannot cross the blood brain barrier, leaving brain H1 receptors open, and prevent drowsiness

in the stomach histamine is produced by

the stomach cells

once histamine is produced

binds to H2 receptors and stimulus the secretion of stomach acids

sold as Tagamet reduces stomach acid secretions, and is therefore an anti-ulcer medication

cimetidine