bio 1102

nervous system

nervous system

specialized system that allows rapid, long-distance communication among cells

central nervous system

brain and spinal cord

peripheral nervous system

all nerves connected to CNS

neuron (nerve cell)

special cells that conduct electrical impulses

sensory neuron

since environment send signals

nocieptor

send pain signals to CNS. detect damage to body

motor neuron

attach to muscles and glands and make them work. receive signals from CNS

cerebral palasy

lack of GABA absorption in nerves causes almost permanent muscle contraction

sciatic nerve

longest nerve cell in the body, running from the lower back to your feet. If irritated or compressed, can cause shooting pains down the leg called sciatica

mirror neuron

neuron fires when animal ats and when sees another animal act

reflex arc

involving response to an external stimulus. direct connection between sensory and motor neuron without connection to brain

analgesic

painkillers that don’t knock you out

acetaminophen

blocks enzyme cyclo-oxygenase (COX3), which blocks formation of prostaglandins in cells (eg., tylenol, nyquil, and robitussin)

NSAID

(non-steroidal anti-inflammatory drug): blocks COX enzymes to block prostglandins hormone. (eg., aspirin, ibuprofen, advil, motrin, aleve)

kidneys

NSAIDS are hard on

opiates

occur naturally

opioids

are human made

brain, spinal cord, and digestive tract

opiate receptors are in the *,*,_

somatoform disorders

involve physical pain but with no clear physical explanation

fibromaylgia

chronic body-wide pain. increased sensitivity to pain in CNS. more common in females

chronic fatigue syndrome

extreme fatigue that not explained by an existing medical condition. Rest doesn’t help. some people develop after having viral infections

conversion disorder

a person experiences blindness, paralysis, seizures, or other symptoms appearing after a period of significant emotion/ physical distress or psychological conflict

pain disorder

like fibromyalgia, but the pain is thought to be caused by psychological stress. the pain may be debilitating, and the duration from a few days to many years

gas

you have taste buds on your tongue that detect bitterness and when they do they release _ that helps kill bacteria and helps prevent infection

neurons and reproduction

some neurons release gases

block a natural enzyme that blocks (ND), allowing (ND) to work

how do erectile dysfunction (ED) drugs work?

neuron anatomy

specialized cell with limited ability to grow, dendrites can keep growing

cell body

main part of cell with nucleus and organelles

dendrite

bring information to cell body

axon

cell information away from cell body

synapse

tiny spaces between nerve cells, or between nerve and other cells

myelin sheath

lipid wrap around the axon

a. insulation

b. make nerve impulses faster

functions of myelin sheath

membrane (resting potential)

the resting difference in charge between inside and outside of a cell

negatively

at rest, the inside of a nerve cell is _ charged?

positively

at rest, the outside of a nerve cell is _ charged?

action potential

temporal reversal of charge between outside and inside of nerve cell

sodium (NA+)

is primarily responsible for starting an action potential

block any of these and you block action potentials

ion transporters in the nerve cell membrane

sodium channel

a protein channel in nerve cell membrane that controls movement of sodium ions into the cell. At rest, no sodium is flowing into the nerve cell. passive transport

potassium channel

a protein channel in the nerve cell membrane that controls movement of potassium ions out of the cell. at rest, no potassium is moving. passive

sodium-potassium pump

uses ATP energy to restore nerve cell to its resting charge. active. pumps sodium back out and potassium back in

cystic fibrosis

a mutated CFTR ion channel protein that controls flow of water and chloride ions across cell membranes block the channel closed so ions cannot flow across. causes buildup of mucus

hormones secreted into synapse allow action potential to cross to next cell

what happens when action potential reached end of axon?

neurotransmitters

hormones secreted into the synapse

in small vesicles at the tips of the axons

where are neurotransmitters stored?

calcium ions (Ca2+) flowing into nerve cell

what causes the release of neurotransmitters into the synaptic space?

either re-absorbed and re-used or destroyed by enzymes

after neurotransmitters are used, what happens to them?

depression

low levels of norepinephrine, dopamine, or serotonin seem to play a role in depression

antidepressants

often work by blocking the re-uptake of the feel-good neurotransmitters

1. cocaine blocks re-uptake of dopamine

2. brain makes enzymes to destroy extra dopamine

3. addiction is caused because when not cocaine, the brain keeps destroying dopamine; thus, the user feels depressed because of low dopamine levels and won’t feel good again for perhaps 30 days until brain functions are completely restored. or, if the user cannot wait, they can use cocaine again to feel good right way… this is the part that will cause the addiction… feeling depressed unless use cocaine

4. ultimately, tolerance develops, and brain needs more and more cocaine to feel the same high

cocaine addiction

neurotoxins

powerful nervous system poisons; many block ion channels from opening and closing

alcohol

at high doses, can block potassium channels open and make them leaky, even at rest. this lowers the membrane potential and causes slower reactions and slurred speech

novocaine

works by blocking sodium (Na+) channels closed. no pain signals sent to brain

golden frog

deadliest vertebrate on Earth. batrachotoxin blocks sodium channels (Na+) open and destroys membrane potential. toxins may from from the food (beetles) this animal eats

puffer fish

second deadliest vertebrate on earth. tetrodoxtin binds to and blocks sodium channels (Na+) closed. toxin produced by bacteria living inside this animal on liver and reproductive tissues

brainstem

survival functions, being alert and awake

pons

regulates breathing

midbrain

coordinates hearing and visual reflexes

medulla

heart rate, swallowing, vomiting, resting, and digestion

fainting

vagues nerve sends nbody into emergency “rest” mode. whole body vasodilation and loss of blood pressure to brain causes fainting. many causes

diencephalon

homeostasis, sleep, thirst, hunger, sex drive, anger

sleep

functions in consolidating learning and memory

dreams (oneirology)

replay events that happened recently and prepare for future events. during REM sleep most motor skills are paralyzed

cerebellum

coordinate muscles, balance, body position

cerebral cortex

outer layers of cerebrum in mammals

cerebrum

memory, abstract thought, sensory perception, language

dopamine

in the brain, it is important in mood and motivation. in the rest of the body, it often acts to reduce activity of things, like digestion, insulin production, lymphocytes, and vasoconstriction

glutamate

important excitatory neurotransmitter (speeds impulses) by allowing and charges ions into nerve

GABA

most important inhibitory neurotransmitter in the body. slow impulses by allowing Cl- ions into cell. alcohol binds to these receptors and holds them open longer

nicotinic receptors

primary action is to increase speed of neuron firing. activated by the neurotransmitter. acetylcholine and the drug nicotine. important throughout body, especially in nervous system and skeletal muscles

opioid receptors

found in the brain, spinal cord, PNS, and digestive tract. involved in analgesia

estimated that 20-25% of heroin users become addicted

addiction rate for heroine

fentanyl

50-100 times stronger than morphine and kills you by suppressing breathing, which leads to respiratory acidosis

migranes

recurring headaches that appear related to neurovascular problems or inflammation

contains caffeine and the bromine, stimulants that can cause seizures and heart attacks at high doses

why is chocolate poisonous to dogs and cats?

coma

unconsciousness in which a person cannot respond to stimuli (pain, light, or sound). usually caused by some injury to the cerebral cortex or the RAS reticular activating system (RAS)

seizures (epilepsy)

rapid simulatenous firing of neurons in the brain. many different kinds

tonic-clonic seizure

most serious, whole body convulsions causes brain damage if too long

absence seizures

milder, short seizure, stare into space or move aimlessly. not remember it

BBB

dense mass of cells that block bacteria and large molecules from entering brain. water, CO2, O2, glucose, alcohol, and sometimes viruses get through

genetics, hypertension, radiation, infection

what weakens BBB?

circumventricular organ

weak areas of BBB so brain can monitor blood quality

area postrema

in medulla. detects toxins in blood and makes you vomit

meningitis

brain infection. caused by bacteria, fungi, viruses. infection in CSF leads to inflammation of the protective membranes around the brain and spinal cord (called meninges)

cerbrospinal fluid (CSF)

specialized interstitial fluid made for the brain

concussion

brain hits skull and “bruises”

memory/learning

neural pathways that differ in length and neurotransmitters used

short-term memory

frontal cortex (cerebrum)

long-term memory

hippocampus coordinates memories and links them together in event

alzheimer’s disease

misfolded proteins (tau or amyloid) enter brain and build up, forming plaques

dendrites

what part of the nerve cell may grow after new learning followed by sleeping?

1. practice

2. emotional state

3. re-testing

4. associate new learning with old learning

what factors improve the transfer of information from short-term to long-term memory

dementia

refers to a broad category of brain disorders that cause long-term decline in cognitive function

protein deposition disorders

proteins build up in brain and impair brain function or cell repair

CTE

chronic traumatic encephalopathy. Tau proteins build up in brain

ADHD

attention depict, hyperactivity disorder. trouble focusing lose attention quickly

Autism spectrum disorder

brain disorders characterized by difficulty in social interaction, verbal and nonverbal communication

anorexia nervosa

eating disorder or self-starvation and loss of 15% or more of ideal body weight

Bulimia nervosa

eating disorder in which extreme overeating (binge) is often follow by vomiting (purge) and feelings of guilt or shame. patients do not lose weight like anorexia patients