Transcript Nervous system - local

NERVOUS SYSTEM
Jenna Scarbrough
FUNCTIONS AND ORGANS
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Transmits signals throughout the body
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Coordinates voluntary/involuntary actions
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Separated into the Central and Peripheral Nervous Systems
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Made up of the brain, spinal cord, nerves, neurons
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The inside of a neuron is negative, while the outside is positive, which creates a
membrane potential. At a resting potential, gated sodium channels are closed, as well as
most potassium channels. Na+ ions moving into the neuron cause it to become less
negative, and it depolarizes. At this point, an action potential occurs. Action potentials
happen whenever a depolarization increases the membrane voltage to a certain value,
which is the threshold (for mammalian neurons, it is about -55 mV). K+ ions are released
from the neuron, which causes it to become more negative again. Eventually the gated
potassium channels close and the membrane potential returns to the resting potential.
The refractory period is the time after an action potential when a second action potential
cannot be initiated. This is due to the inactivation of sodium channels.
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Neurotransmitter: biochemical substance that carries information
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Sent from the axon through the empty space called the synapse, and arrives at the
dendrite
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Play a role in our mental health
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Acetylcholine: voluntary movement, learning, memory, sleep
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Dopamine: movement, attention, learning
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Norepinephrine: eating, sleep
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Epinephrine: energy and glucose metabolism
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Serotonin: mood, sleep, appetite, behavior
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GABA: excitation and energy
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Endorphins: pain relief, pleasure
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EPSP (excitatory postsynaptic potential)—positive ions flow into the postsynaptic cell and
causes a temporary depolarization.
• Makes it easier for a neuron to fire an action potential
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IPSP (inhibitory postsynaptic potential)—the flow of negative ions into the cell causes a
change in membrane voltage by the activation of inhibitory neurotransmitter receptors.
• Lowers the firing rate of a neuron and makes it more difficult for the cell to fire an
action potential
ALZHEIMER’S
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Most common form of dementia (accounts for 50-80% of cases)
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Caused by the destruction of brain cells
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Memory loss, disorientation, mood and behavior changes, etc.
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Affects over 5 million Americans
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There is no cure, but it can be treated with some medications such as antidepressants,
anxiolytics, or antipsychotic medications
PARKINSON’S
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Neurons are slowly and progressively injured and then degenerate or die
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Involuntary trembling, rigid and stiff muscles, change in facial expression, limping, etc.
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Treated with medication (occasionally), implanting a deep brain stimulation device, and
through rehabilitation
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Affects about 1 million Americans; 60,000 new cases each year
BIBLIOGRAPHY
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http://wps.aw.com/wps/media/objects/443/454059/st0807.html
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http://serendip.brynmawr.edu/bb/kinser/Structure1.html
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http://allpsych.com/psychology101/neurotransmitters.html
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http://www.alz.org/alzheimers_disease_treatments_for_behavior.asp
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http://www.umm.edu/parkinsons/facts.htm
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textbook
DIGESTIVE SYSTEM
Jenna Scarbrough
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The digestive system serves to turn the food one eats into energy that can be stored
and used, and to dispose of any waste that is left over.
PURPOSE
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Mouth and salivary glands: The first step in digestion starts with the mouth, which
breaks food down into smaller bits. Saliva then mixes in and begins to chemically
break down the food.
FUNCTIONS
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Pharynx (throat): passageway allowing foods/liquids to pass through to the
esophagus; also allows air to be conducted to and from the trachea during
respiration.
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Esophagus: receives food from mouth and delivers it to the stomach.
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Stomach: stores food and uses acids from the lining of the organ, as well as
enzymes, to assist in breaking food down further.
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Pancreas: secretes enzymes into the small intestine to break down lipids,
carbohydrates, and proteins; also responsible for making insulin, which regulates the
body’s blood sugar.
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Liver/gall bladder: The liver secretes bile into the small intestine, which breaks down
the fat into smaller pieces when mixed with food. The bile is stored in the gall
bladder. The liver also serves to detoxify harmful chemicals.
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Small intestine: consists of three parts—duodenum, which is mainly responsible for
continuously breaking down the food, and the jejunum and ileum, which mainly
absorb nutrients from the food and enter them into the bloodstream. This organ uses
enzymes from the pancreas and bile from the liver to break down the food.
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Large intestine: consists of the cecum and ascending, transverse, descending, and
sigmoid colons. This organ is responsible for processing waste. Water is removed as
it passes through the colon and is then stored in the sigmoid colon until it is emptied.
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Rectum: this organ holds waste and notifies the brain that it needs to be disposed of.
If the contents can be released, the sphincters relax and the organ contracts, which
disposes it of any contents.
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Anus: detects rectal contents and notifies brain as to whether they are solid, liquid, or
gas. The internal sphincter helps keep these contents inside the body, and the
external sphincter holds it in until we can properly release the contents.
The digestive tract (organs/areas through which the food actually passes) includes
the mouth, esophagus,
small intestine, large intestine,
rectum, and anus.
DIGESTIVE
TRACTstomach,
VS. ACCESSORY
ORGANS
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Accessory organs include the salivary glands, liver, pancreas, and gall bladder.
Physical digestion: the process of breaking food down into smaller pieces, changing
the shape and
size,CHEMICAL
but not the chemical
structures.
PHYSICAL
VS.
DIGESTION
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Chemical digestion: the process of breaking food down into small, organic materials
that the body can absorb into the body.
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Proteases are responsible for breaking down food into proteins
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Lipase for lipids
ASSISTING
ENZYMES
• Amylase for carbohydrates
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Carbohydrates: starch and sugar
BREAKDOWN
• Saliva and pancreaticOF
juicesCARBS
break starch into maltose. The maltose molecules travel
to the small intestine, where they are broken down into glucose, which enters the
bloodstream and is carried to the liver.
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Sugar (usually sucrose) is divided in the small intestine into glucose or fructose and
then enters into the blood. Lactose is changed into absorbable molecules in the
intestine.
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Proteins: The stomach starts the digestive process of digesting the large molecules.
The small intestine (with the help of pancreatic juices) break down the molecules into
amino acids.
BREAKDOWN OF PROTEINS
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Lipids (fats): bile from the liver dissolves fats into tiny droplets, and pancreatic and
intestinal enzymes convert the molecules from large to smaller pieces.
BREAKDOWN OF FATS
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Diarrhea: a watery stool or increased frequency, or both. Other symptoms can
include nausea, bloating, or fever.
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Caused by a bacterial or viral infection, food poisoning or allergies, parasites, a
reaction to medications, etc.
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Can often indicate a more serious disease
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Can be treated with over-the-counter meds, or by drinking lots of fluids and avoiding
foods with high fiber and caffeine contents.
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The average adult can experience diarrhea up to four times a year.
DIARRHEA
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Indigestion (dyspepsia): pain or burning in the upper abdomen along with feeling full,
feeling bloated or nauseous, constipation, and sometimes vomiting.
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Causes include stomach ulcers, bacterial infections, lactose intolerance, anxiety or
depression, a reaction to medicine, smoking, or drinking too much alcohol.
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Can be treated with antibiotics, antacids, and avoiding certain foods or situations.
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Chronic indigestion (or gastritis) occurs in 2/10,000 people, while the acute form
occurs in 8/1,000.
INDIGESTION
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http://my.clevelandclinic.org/anatomy/digestive_system/hic_the_structure_and_functi
on_of_the_digestive_system.aspx
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http://www.britannica.com/EBchecked/topic/1081754/human-digestivesystem/45316/Pharynx
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http://www.sciencebob.com/research/digestion.php
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http://medicalcenter.osu.edu/patientcare/healthcare_services/digestive_disorders/dig
estive_system/Pages/index.aspx
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http://www.differencebetween.com/difference-between-mechanical-digestion-and-vschemical-digestion/
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http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/
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http://www.globalhealingcenter.com/digestive-disorders/diarrhea
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http://my.clevelandclinic.org/disorders/Gastritis/hic_Gastritis.aspx
BIBLIOGRAPHY
ENDOCRINE SYSTEM
Jenna Scarbrough
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Function: chemical signaling through hormones
• Metabolism
• Absorption of nutrients
• Reproduction
• Water and electrolyte balance
• Birth
• Lactation
• Growth and development
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Homeostasis: The tendency of an organism or a cell to regulate its internal conditions,
usually by a system of feedback controls, so as to stabilize health and functioning,
regardless of the outside changing conditions
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-http://www.biology-online.org/dictionary/Homeostasis
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The endocrine system uses homeostasis to regulate electrolyte concentration, maintain plasma
volume, and help regulate metabolism.
NEGATIVE FEEDBACK
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Definition: feedback that reduces an output of a system
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Example: Calcium levels in the blood can be regulated through a negative feedback
system. The parathyroid glands secrete more of the parathyroid hormone when low
calcium levels are detected in the blood. The hormone increases calcium levels into the
bloodstream. If the levels are too high, the parathyroid glands reduce the hormone
production.
CELL SIGNALING
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Endocrine cells secrete hormones into extracellular fluids to reach the target cells via the
bloodstream.
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Local regulators use diffusion to reach he target cells over short distances.
INSULIN
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Insulin triggers the uptake of glucose from the bloodstream when blood glucose levels
rise above a certain point, to decrease the blood glucose levels.
• Also slows glycogen breakdown and inhibits glucose production
DIABETES I VS. II
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Type I Diabetes: the body does not produce insulin
• Insulin is taken regularly through injection
• Considered an autoimmune disease
• About 15% of the diabetic population
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Type II Diabetes: cells do not respond to the insulin, or not enough is being produced
• Most cases brought on by unhealthy lifestyles, e.g. being overweight, lacking exercise 
insulin resistance
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Because the glucose
ADDISON’S DISEASE
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A disorder where the adrenal glands do not produce enough of the hormones
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AD is considered a rare disease, with 8,800 cases in the US, but considered an
understimation.
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Causes:
• immune system mistakenly attacking the gland (autoimmune disease)
• HIV, tuberculosis, or fungal infections
• Hemorrhage, blood loss
• Use of anticoagulants
• Other autoimmune diseases
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Symptoms:
• Change in heart rate or blood pressure
• Chronic diarrhea, nausea, vomiting
• Paleness
• Darkening of skin
• Mouth lesions
• Extreme weakness and fatigue
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Glococorticoids and mineralocorticoids are used to treat Addison’s disease but must be
used for life.
BIBLIOGRAPHY
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http://www.britannica.com/EBchecked/topic/186893/human-endocrinesystem/272445/The-endocrine-system-and-the-human-system
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http://www.anewlife.co.uk/hormones_endocrine_glands.html
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https://www.nlm.nih.gov/medlineplus/endocrinesystem.html
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http://www.pennmedicine.org/health_info/body_guide/reftext/html/endo_sys_fin.html
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http://www.medicalnewstoday.com/articles/7504.php
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https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001416/
EXCRETORY SYSTEM
Jenna Scarbrough
FUNCTION
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Eliminates waste, useless by-products, maintains a steady chemical concentration
and eliminates harmful buildups
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Blood passes through the kidneys and leaves unwanted water, minerals, and urea,
which becomes urine.
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The urine is passed through two separate tubes called ureters, which lead to the
bladder.
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The bladder is made of muscular tissue that stretches to accommodate the storage
of urine. The muscles contract during urination, which forces the contents into the
urethra.
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The urethra expels urine from the body.
KIDNEY
NITROGENOUS WASTES
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Ammonia—can only be tolerated at low concentrations
• Aquatic species use ammonia excretion the most. The molecules are highly
soluble, so they easily diffuse into the surrounding water.
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Urea—low toxicity, high energy cost
• 100,000 times less toxic than ammonia
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Mammals, amphibians, sharks, turtles, and some marine bony fish excrete urea
• Many amphibians excrete ammonia when the live in the water and switch to
urea when they live on land
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Combination of ammonia and carbon dioxide that is produced in the liver
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Allows for less water to be sacrificed
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Uric Acid—relatively nontoxic
• Used by insects, reptiles, land snails, and birds
• Excreted as a semisolid paste, with little water loss
• Least energy efficient
• Small amounts are produced by humans due to purine breakdown
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Filtration is the extraction of water, solutes, and metabolic wastes from body fluids.
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Reabsorption is the recovery of solutes and water from filtrate.
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Secretion—cells of the tubules remove certain molecules and ions from the blood
and deposit these into the fluid within the tubules.
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Excretion—if tubular reabsorption decreases, calcium is lost by secretion into urine.
KIDNEY STONES
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solid piece of material that becomes highly concentrated and stays in the kidneys or
travels down the urinary tract
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More than 300,000 trips to the ER a year by Americans
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Syptoms: pain while urinating, sharp pains in the lower abdomen, nausea, vomiting,
or no symptoms if the stones are small enough
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Treatments:
• Shock wave lithotripsy crushes the stones
• Percutaneous nephrolithotomy—removed with a nephroscope
• A ureteroscope retrieves the stone or destroys it with laser energy
CYSTITIS
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Inflammation of the bladder
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Symptoms—discomfort in the pelvic area, low-grade fever, pressure in the lower
abdomen, strong, persistent urge to urinate, a burning sensation when urinating,
passing small amounts
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Treated with antibiotics
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8 million women in America. Females are 5 times more likely to contract it than men.
BIBLIOGRAPHY
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http://library.thinkquest.org/07aug/01618/excretory.html
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http://www.webmd.com/urinary-incontinence-oab/picture-of-the-bladder
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http://www.primehealthchannel.com/urethra-definition-anatomy-function-pain-andpictures.html
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Campbell and Reece online textbook
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http://ex-anatomy.org/nitro.html
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http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Kidney.html
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http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/thyroid/calcium.html
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http://kidney.niddk.nih.gov/KUDiseases/pubs/stonesadults/index.aspx
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https://www.mayoclinic.com/health/cystitis/DS00285
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https://www.ncbi.nlm.nih.gov/pubmed/15592041
IMMUNE SYSTEM
Jenna Scarbrough
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Function: defends the body against infectious organisms and other invaders
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Major organs:
• Thymus
• Spleen
• Lymph nodes
• skin
• Tonsils
• White blood cells (leukocytes)
RECOGNIZING PATHOGENS
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The body uses receptors to bind to foreign molecules
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Innate immunity uses the skin, mucus, saliva, and other barrier defenses in every animal
to prevent and immediately fight infection, and to destroy pathogens after they have
entered the body
• Tuburculosis
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Humans and other vertebrates also use acquired (adaptive) immunity that activates
responses more slowly, after innate immunity responses have been activated. The
response is caused by having previous exposure to the pathogen and being able to
recognize it.
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B and T cells, called lymphocytes, recognize and inactivate foreign molecules.
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These cells contribute to immunological memory, or a response to previously encountered
foreign molecules.
• These large foreign molecules are usually either proteins or polysaccharides.
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Antigens are recognized through specific receptors located in the plasma membranes of
the B and T cells.
• B cells can give rise to plasma cells that secrete antibodies, which are soluble forms
of antigen receptors.
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T cells begin antigen recognition when a pathogen either infects or engulfs a host cell.
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Peptide antigens break down the pathogen into smaller pieces.
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The peptide antigens bind to MHC (major histocompatability complex), which results in
antigen presentation—the display of the antigen fragment on the cell.
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This either activates immune responses or targets the infected cell for destruction.
ACTIVE AND PASSIVE IMMUNITY
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Both can be induced artificially
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Active immunity is long-lasting and B and T cells produce memory cells that target
specific pathogens.
• Can result from natural infection or immunization
• Vaccinations such as cowpox, smallpox, polio
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Passive immunity is short-term immunity that is conferred by the transfer of antibodies
• Transfer of antibodies from mother to fetus or nursing infant
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The humoral immune response activates B cells to secrete antibodies that circulate in the
blood and lymph
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The cell-mediated immune response works with T cells to identify and destroy target cells.
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T (thymus) lymphocytes and B (bursa of Fabricius) lymphocytes recognize foreign cells
and molecules and function only in the acquired immune system.
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The cells undergo cell division when activated, and the daughter cells fight future
infections against the same microbe.
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Some T cells activate other lymphocytes, while others detect and kill host cells.
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B cells secrete soluble receptor proteins that attack foreign molecules and cells
circulating in body fluids.
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B cell receptors recognize and bind to an intact antigen, while T receptors bind only to
antigen fragments presented on the surface of host cells.
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Antibiotics treat bacteria and not viruses because bacteria are single-celled organisms
that reproduce separately outside of body cells.
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Viruses rely on body cells to reproduce. Antibiotics kill off the bacteria or prevent them
from continuing to reproduce, but cannot work on viruses without killing human cells,
which is what the viruses were doing in the first place.
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Viruses are not living, so antibiotics cannot attack them.
HIV/AIDS
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Human immunodeficiency virus/acquired immunodeficiency syndrome—destroys T cells
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Transmitted mainly through sexual intercourse, contaminated blood transfusions, needles,
etc.
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Many people experience flu-like symptoms several weeks after infection, while others
experience none.
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During clinical latency, which lasts from 3 to 20 years (averaging 8), there are at first no
symptoms, but eventually fever, weight loss, muscle pains, and other symptoms occur.
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Over 1 million people are infected with HIV in the US
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1 in 5 people living with HIV are unaware of their infection.
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There is no cure for AIDS, but there are a number of drugs that prevent HIV from copying
itself, creates faulty building blocks, disable protease, and prevent the virus from entering
cells.
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Types of treatments:
• Nucleotide/nucleoside reverse transcriptase inhibitors (NRTIs)
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
• Protease inhibitors (PIs)
• Entry/fusion inhibitors
ALLERGIES
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Allergies—hypersensitive responses to antigens called allergens
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Symptoms: red eyes, itchiness, runny nose, eczema, hives, asthma, abdominal pain,
diarrhea, sinusitis, etc.
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Can be caused by foods, certain proteins (latex), toxins interacting with proteins (certain
plants), etc.
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Can be tested by skin or blood tests
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Treated with antagonistic drugs, which include antihistamines, epinephrine,
glucocordicoids, etc. and antileukotrienes, which include montelukast or zafirlukast; and
anticholinergics, decongestants, etc.
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Allergies are on the rise
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1 in 5 people have allergy or asthma symptoms
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55% of people test positive to one or more allergens
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http://www.mayoclinic.com/health/hiv-aids/DS00005/DSECTION=treatments-and-drugs
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http://aids.gov/hiv-aids-basics/hiv-aids-101/statistics/
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http://www.webmd.com/allergies/allergy-statistics
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textbook