Nervous system

1. Nervous system Jenna Scarbrough

2. Functions and organs • Transmits signals throughout the body • Coordinates voluntary/involuntary actions • Separated into the Central and Peripheral Nervous Systems • Made up of the brain, spinal cord, nerves, neurons

6. 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.

8. Neurotransmitter: biochemical substance that carries information • Sent from the axon through the empty space called the synapse, and arrives at the dendrite • Play a role in our mental health • Acetylcholine: voluntary movement, learning, memory, sleep • Dopamine: movement, attention, learning • Norepinephrine: eating, sleep • Epinephrine: energy and glucose metabolism • Serotonin: mood, sleep, appetite, behavior • GABA: excitation and energy • Endorphins: pain relief, pleasure

9. 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 • 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

10. Alzheimer’s • Most common form of dementia (accounts for 50-80% of cases) • Caused by the destruction of brain cells • Memory loss, disorientation, mood and behavior changes, etc. • Affects over 5 million Americans • There is no cure, but it can be treated with some medications such as antidepressants, anxiolytics, or antipsychotic medications

11. Parkinson’s • Neurons are slowly and progressively injured and then degenerate or die • Involuntary trembling, rigid and stiff muscles, change in facial expression, limping, etc. • Treated with medication (occasionally), implanting a deep brain stimulation device, and through rehabilitation • Affects about 1 million Americans; 60,000 new cases each year

12. bibliography • http://wps.aw.com/wps/media/objects/443/454059/st0807.html • http://serendip.brynmawr.edu/bb/kinser/Structure1.html • http://allpsych.com/psychology101/neurotransmitters.html • http://www.alz.org/alzheimers_disease_treatments_for_behavior.asp • http://www.umm.edu/parkinsons/facts.htm • textbook

13. DIGESTIVE SYSTEM Jenna Scarbrough

14. Purpose • 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.

16. Functions • 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.

17. 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.

18. Esophagus: receives food from mouth and delivers it to the stomach.

19. Stomach: stores food and uses acids from the lining of the organ, as well as enzymes, to assist in breaking food down further.

20. 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.

21. 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.

22. 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.

23. Large intestine: consists of the cecumand 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.

24. 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.

25. 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.

26. Digestive tract vs. accessory organs • The digestive tract (organs/areas through which the food actually passes) includes the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. • Accessory organs include the salivary glands, liver, pancreas, and gall bladder.

27. Physical vs. chemical digestion • Physical digestion: the process of breaking food down into smaller pieces, changing the shape and size, but not the chemical structures. • Chemical digestion: the process of breaking food down into small, organic materials that the body can absorb into the body.

28. Assisting enzymes • Proteases are responsible for breaking down food into proteins • Amylase for carbohydrates • Lipase for lipids

29. Breakdown of carbs • Carbohydrates: starch and sugar • Saliva and pancreatic juices 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. • 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.

30. Breakdown of proteins • 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.

31. Breakdown of fats • Lipids (fats): bile from the liver dissolves fats into tiny droplets, and pancreatic and intestinal enzymes convert the molecules from large to smaller pieces.

32. Diarrhea • Diarrhea: a watery stool or increased frequency, or both. Other symptoms can include nausea, bloating, or fever. • Caused by a bacterial or viral infection, food poisoning or allergies, parasites, a reaction to medications, etc. • Can often indicate a more serious disease • Can be treated with over-the-counter meds, or by drinking lots of fluids and avoiding foods with high fiber and caffeine contents. • The average adult can experience diarrhea up to four times a year.

33. Indigestion • Indigestion (dyspepsia): pain or burning in the upper abdomen along with feeling full, feeling bloated or nauseous, constipation, and sometimes vomiting. • Causes include stomach ulcers, bacterial infections, lactose intolerance, anxiety or depression, a reaction to medicine, smoking, or drinking too much alcohol. • Can be treated with antibiotics, antacids, and avoiding certain foods or situations. • Chronic indigestion (or gastritis) occurs in 2/10,000 people, while the acute form occurs in 8/1,000.

34. Bibliography • http://my.clevelandclinic.org/anatomy/digestive_system/hic_the_structure_and_function_of_the_digestive_system.aspx • http://www.britannica.com/EBchecked/topic/1081754/human-digestive-system/45316/Pharynx • http://www.sciencebob.com/research/digestion.php • http://medicalcenter.osu.edu/patientcare/healthcare_services/digestive_disorders/digestive_system/Pages/index.aspx • http://www.differencebetween.com/difference-between-mechanical-digestion-and-vs-chemical-digestion/ • http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/ • http://www.globalhealingcenter.com/digestive-disorders/diarrhea • http://my.clevelandclinic.org/disorders/Gastritis/hic_Gastritis.aspx

35. Endocrine System Jenna Scarbrough

36. Function: chemical signaling through hormones • Metabolism • Absorption of nutrients • Reproduction • Water and electrolyte balance • Birth • Lactation • Growth and development

37. 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 • -http://www.biology-online.org/dictionary/Homeostasis • The endocrine system uses homeostasis to regulate electrolyte concentration, maintain plasma volume, and help regulate metabolism.

39. Negative feedback • Definition: feedback that reduces an output of a system • 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.

40. Cell signaling • Endocrine cells secrete hormones into extracellular fluids to reach the target cells via the bloodstream. • Local regulators use diffusion to reach he target cells over short distances.

41. Insulin • 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

42. Diabetes I vs. II • 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 • 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 • Because the glucose

43. Addison’s disease • A disorder where the adrenal glands do not produce enough of the hormones • AD is considered a rare disease, with 8,800 cases in the US, but considered an understimation. • Causes: • immune system mistakenly attacking the gland (autoimmune disease) • HIV, tuberculosis, or fungal infections • Hemorrhage, blood loss • Use of anticoagulants • Other autoimmune diseases

44. Symptoms: • Change in heart rate or blood pressure • Chronic diarrhea, nausea, vomiting • Paleness • Darkening of skin • Mouth lesions • Extreme weakness and fatigue • Glococorticoids and mineralocorticoids are used to treat Addison’s disease but must be used for life.

45. Bibliography • http://www.britannica.com/EBchecked/topic/186893/human-endocrine-system/272445/The-endocrine-system-and-the-human-system • http://www.anewlife.co.uk/hormones_endocrine_glands.html • https://www.nlm.nih.gov/medlineplus/endocrinesystem.html • http://www.pennmedicine.org/health_info/body_guide/reftext/html/endo_sys_fin.html • http://www.medicalnewstoday.com/articles/7504.php • https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001416/

46. Excretory System Jenna Scarbrough

47. Function • Eliminates waste, useless by-products, maintains a steady chemical concentration and eliminates harmful buildups

48. Blood passes through the kidneys and leaves unwanted water, minerals, and urea, which becomes urine. • The urine is passed through two separate tubes called ureters, which lead to the bladder.

49. 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. • The urethra expels urine from the body.

50. Kidney