Digestive System - Review Sheet for Test #4 | BIO 1004, Study notes of Physiology

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Test 4 Notes- April 20th Digestive System Chemical digestion uses enzymes to break down: Carbs into simple sugars Proteins into amino acids Lipids into glycerol and fatty acids; most difficult compared to the other two Organs/Structures of Digestive System Mouth Teeth: used for mastication (chewing) to increase surface area of food to absorb more nutrients Tongue: rejects bad foods; forms bolus; moves food; important in swallowing process Salivary Glands: produce enzyme called salivary amylase; starts breaking down carbs; lubrication for swallowing Lips: gather food Cheeks: hold food inside the mouth Pharynx: common junction between respiratory and digestive systems; amylase is still working here but there it's just a passageway Esophagus: tube; smooth muscle; lined with a mucous membrane for lubrication Behind the trachea, which protects it from mechanical damage Very pliable and expandable/subject to damage Peristalsis: rhythmic contractions once swallowing has started; the way that all food moves through the entire digestive system Stomach: Has sphincter between esophagus and stomach Contains HCl with a pH of 2 Just a holding chamber; very little digestion here Bolus becomes chyme (liquid) Salivary amylase is destroyed here No lipid digestion; moderate amount of protein digestion by enzymes HCl kills bacteria and also softens tendons and ligaments in meat Made of smooth muscle, which is made up of proteins, but stomach isn't digested because of a very thick mucus lining that resists digestion Pepsin: enzyme in stomach that breaks down protein Water, aspirin and alcohol are absorbed through lining into blood stream. Complications Ulcer: occurs when mucus thins and stomach digests itself; caused by helicobacter pylori; invades stomach lining, produces small amounts of ammonia to neutralize stomach acids in small areas Stress, alcohol and spicy foods cause mucus to thin but bacteria causes the infection Acid Reflux/Heartburn: sphincter between esophagus and stomach fails; acid and proteolytic enzymes damage and destroy esophagus Pancreas Produces digestive juices: contains many enzymes to break down all macromolecules; contains alkali solution for neutralization Comes in at top of SI to stop digestion of proteins that happened in stomach Trypsin: enzyme made in pancreas and secreted to Small Intestine to break down proteins Amylase: enzyme made in pancreas and secreted to Small Intestine to break down carbs Lipase: enzyme made in pancreas and secreted to Small Intestine to break down fats Ribonuclease: enzyme made in pancreas and secreted to Small Intestine to break down nucleic acids Elastase: enzyme make in pancreas and secreted into Small Intestine to break down connective tissue Small Intestine Majority of digestion and absorption happen here Absorption occurs in capillary beds Thin mucus lining Small amounts of chyme come in in intervals through sphincter Lining is rough and lined with villi to increase surface area and make absorption ore efficient Each villi contains a capillary bed, where simple sugars and amino acids are absorbed Each villi contains a lymphatic vessel called a lacteal to absorb glycerol and fatty acids Sugars, water, vitamins, minerals and Amino Acids are absorbed by capillary beds in villi of Small Intestine. Fatty Acids and Glycerol are absorbed by lacteal in villi of Small Intestines. Liver Controls amount of nutrients in blood that goes to the rest of the body Removes more nutrients and stores them Produces bile: enters SI and acts as an emulsifier; NOT AN ENZYME Emulsifier: breaks fat into small droplets for increased surface area and makes lipase more efficient Large Intestines Larger lumen than SI Appendix: fingerlike projection near junction of SI and LI; also part of lymphatic system Majority of nutrient absorption takes place in SI and there is very little absorption in the LI Functions to absorb water from chyme Dirtiest place in the body; more bacteria than anywhere in the body that use undigested chyme as food source Prevent infection Produce vitamin K and some B vitamins Produce odors and gas Rectum: 10 to 12 inches of LI; storage area for feces Anus: sphincter; allows control of elimination Urinary System Organs Kidneys: filtration of blood from urine Only filters plasma Trys to get waste out of plasma, such as nitrogenous waste, and lose water in the process Cellular digestion (not just in the digestive system) Protein digestion in cells/Deamination Ammonia: NH3; toxic, lots is made; cells immediately put it into blood to go to the liver; combines with CO2 to form urea in liver Urea: ammonia + CO2; formed in liver; much less toxic; contained in plasma Enters kidney and is filtered out, but some water loss is associated Filters blood of impurities Small amounts of ammonia and toxins are removed Osmoregulation: regulate viscosity of blood Either absorb water into blood or they don't Forcing water out of blood is not an option by kidneys Controls salt content of blood Stuctures Renal Pelvis: hollow area that stores small amounts of urine for brief time; connecting point for ureters, renal artery and renal vein Renal Medulla: central portion of kidney where most filtration takes place Renal Cortex: outer portion- dense layer of tissue that surrounds medulla; carries our a small percentage of filtration; provides protection Nephrons: microscopic structures found in medulla and cortex that filter plasma and produce urine Glomerulus: capillary bed found inside Bowman's Capsule Bowman's Capsule: starting point of nephron; enlarged hollow area which contains and surrounds the capillary beds Proximal Convoluted Tubule (PCT): tube that connects to Bowman's Capsule Days 6-13: proliferation stage- uterine lining rebuilds itself Day 14: ovulation- ova is released from either the right or left ovary Days 15-28: secretory phase- uterus prepares for implantation if fertilization has occurred; if implantation does not occur, then the cycle repeats itself Birth Control Abstinence: 100% effective Vasectomy: almost 100%; vas deferens for each testicle is severed Tubal ligation: almost 100%; more invasive; oviducts are severed; Oral Contraception: almost 100%, if used correctly; hormones that prevent ovulation; national average of effectiveness is 85%; some antibiotics interfere; prevents ovulation Contraceptive implants: 90%; hormones are planted beneath the skin in time released capsule; hormones prevent ovulation; some antibiotics interfere; can't control dosage very well; prevents ovulation Contraceptive injections: 99%; injection of hormones; benefits: take once every 4-6 months; antibiotics are still a concern; drawbacks: have to wait until it wears off and can be up to a year; prevents ovulation Intrauterine device: IUD; 90%; device implanted in uterus that prevents fertilized egg from implantation Diaphragm: 90%; plastic device that covers the cervix; prevent sperm from entering the uterus; Cervical Cap: 85%; same as diaphragm Male condom: 85% if used correctly; plastic/rubber/vinyl sheath that covers penis; traps sperm and prevents fertilization; Female condom: 85% plastic sleeve that fits inside vagina to trap sperm and prevent fertilization; Coitus interruptus: 75%; withdrawal before ejaculation; poor form of BC Jellies, creams and foams: 75%; have spermicidal chemicals added to them to try to kill the sperm; when used with other forms of BC, they become more effective; with condom=95% Natural Family Planning: 70%; avoid first 5 days of menstrual cycle and avoid a few days before and after day 14; sperm can survive 48 hours in female Douche: 70%; inject a liquid that has spermicide in it into the female; theory is that you wash out the sperm but it's not very good because fertilization takes place higher in tract; douche pushes sperm higher intro tract Sexually Transmitted Disease AIDS: viral infection; acquired immunodeficiency syndrome; caused by HIV; attacks helper T cells; immune system collapses; victims generally die of diseases that a regular immune system could get rid of easily; incurable; treatable for varying amounts of time; Genital Herpes: viral infection; commonly caused by herpes simplex 2; also caused by simplex 1; both forms can cause cold sores and genital herpes; symptoms: blisters that will rupture and spontaneously heal within several days; blisters will recur; incurable; are methods to control outbreaks; roughly 20% of sexually active individuals have herpes; usually contract other STD's when you have herpes Genital Warts: viral infection; symptoms: warts; can be removed by any method that works for other warts but will most likely return; increase risk of getting other STD's; in females- warts increase the risk of developing genital cancers; no cure but there are treatments; vaccinations available Gonorrhea: bacterial infection; curable; discharge from urethra or vagina; pain during urination; can lead to development of scar tissue in urethra or ova ducts; one of the most common causes of female sterility; lots of cases are asymptomatic; transmitted easily; one of the most common types of STD's; Mississippi has highest rate of all states; Greenville and West Point Chlamydia: bacterial infection; curable; affects deeper regions of reproductive system (ova ducts and vas deferens); very few symptoms; predisposes you to STDs; no long term immunity; one of the leading causes of sterility Syphilis: bacterial infection; curable; occurs in stages; between primary and secondary it's curable Primary: ulcer on genitals; painless; once it clears, no symptoms for up to a year Secondary: rash on palms and soles; spontaneously clears; sometimes it ends here Tertiary: large ulcers anywhere and everywhere called gummas; can be on internal organs, including the brain; not curable anymore, but still treatable Development and Aging Sperm Head: acrosome with enzymes and nucleus Midpiece: mitochondria Tail: swimming Ova Corona radiata: thick outer layer; made of cells from the ovary Zona pellucide: thickened middle layer; proteins Plamsa Membrane Haploid Nucleus Fertilization: one sperm penetrates the egg and the nuclei combine and development begins; happens in the fallopian tubes; requires 100s of sperm but only one fertilizes the ova Stage 1: numerous sperm release contents of acrosome and enzymes dissolve the corona radiata and zona pellucida Stage 2: a single sperm contacts plasma membrane and sets off series of conformational changes Plasma membrane separates from ZP Void between PM and ZP immediately fills with fluid Entire interior of ova begins to rotate Development after Fertilization Cleavage: cell begins to divide with out increasing in size; number of cells increase but size doesn’t Morula: solid call of cells Blastula: cells from center of morula move to outside to produce a hollow ball; some cells remain in cavity and hollow space fills with fluid Gastrula: cells from outside move back into hollow space; form 2 layers of cells but hollow area remains Endoderm: inside layer of cells Ectoderm: outer layer of cells Cells invade the space between endo and ectoderm to produce a 3rd layer known as the mesoderm The three layers together are known as the germ layers/germ cells Each layer makes specific structures in adults Neurula: notochord develops which will eventually be replaced by the spinal cord Germ Layers Ectoderm: skin, brain and neurons, linings of the nose, mouth and anus Mesoderm: muscle, connective tissue, reproductive structures Endoderm: digestive tract, endocrine glands, bladder, and other internal structures Any damage now will cause problems now and later; very delicate right now Implantation: zygote embeds in the uterine lining Placenta: area in uterus where all exchanges between mom and fetus occur exchange of nutrients, waste products, O2, CO2; never blood! Big capillary bed Parts are produced by mom; other parts produced by fetus Network of intertwined capillary beds Can form anywhere in uterus; most likely on side or top Connects to fetus through umbilical cord; umbilical vein carries oxygen rich blood and umbilical artery carries oxygen poor blood Embryonic Development First and second months of pregnancy Week 1: pre embryonic development: zygote is traveling down oviduct; cleavage, morula, and blastula; cell mass may split to form identical twins before it attaches to the uterine wall; Week 2: cell mass arrives at uterus; implantation occurs; placenta begins to form; tissues are being produced Week 3: nervous system begins to develop (neurula); circulatory system begins to develop; embryo is surrounded by amniotic sac which is filled with fluid to protect the embryo from temperature changes and shock/concussion Week 4: tail is present on embryo because spinal cord grows faster than any other structure; head is much larger than any other structure; limb buds are present; eyes, ears and nose appear; heart beats, but you can't hear it yet; liver produces blood cells Second month: arms and legs become more developed; fingers and toes appear; all major organ systems have developed Fetal Development Third and fourth months Head growth slows; eye lashes, eye brows, hair on head, fingernails and nipples; bone starts to replace cartilage; heart beat may be heard; 6 inches long and weighs 6 ounces; start to show; most room taken up is due to amniotic fluid Fifth through Seventh months Movement may be felt; lanugo (fine hair/fur) covers baby; waxy substance called burnix also covers whole body to prevent fluid loss of fetus into amniotic fluid; eyelids open; 12 inches long and weigh 3 pounds; Eighth and Ninth months Head points toward cervix; growth of fetus; 21 inches long and 7.5 pounds; under weight babies do not survive as well as average weight babies; overweight babies used to not survive as well; Birth Through pregnancy, minor contraction occur called Braxton hicks; not harmless unless they become rhythmic Stage 1: mucus plug that has cover birth canal is expelled; amniotic sac breaks; 98% of all women have their amniotic sac ruptured by doc; cervix dilates to about 4 inches Stage 2: contractions every 1 to 2 minutes; crowning begins (able to see top of head in cervix); baby is expelled head first; umbilical cord is cut after baby begins to breathe normally Stage 3: delivery of placenta