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what allows food to travel through your esophagus into the stomach?
peristalsis (contractions of the esophagus)
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Blood leaves the kidneys through the...
renal veins
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As the amount of water in the blood increases, what happens to the rate of water reabsorption in the kidneys?
decreases
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The energy available in foods can be measured by...
burning the foods
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the main organs of the excratory system are the...
kidneys
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What percentage of the filtrate’s water that enters Bowman’s capsule is reabsorbed into the blood?
99%
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List the six nutrients needed by the body.
- water
- carbohydrates
- fats
- proteins
- vitamins
- minerals
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what is the function of the ureter?
carry urine from kidneys to the bladder
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simple carbhydrates
- monosaccharides and disaccharides
- found in sugar, fruits, and honey
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complex carbohydrates
- polysaccharides
- starches found in grains, potatoes, and vegtables
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cellulose
- fiber (complex carbohydrate)
- needed to keep food moving through digestive system
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essential fatty acids
- cannot be made by our bodies, must be consumed
- needed for cell membranes, myelin sheaths, and some hormones
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saturated fats
- no double bonds
- solid at room temperature
- butter and animal fats
- can increase your risk for heart disease
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unsaturated fats
- at least one double bond
- liquid at room temperature
- vegtable oils
- better for diet
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proteins
- needed for growth and repair of skin and muscle
- needed to make some hormones, antibodies, and hemoglobin
- made of amino acids (8 out of 20 are essential, we cannot make them and must obtain them from food)
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vitamins
- essential to our diet
- vitamin k- bacteria in our digestive system
- vitamin d- when exposed to sunlight
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fat soluable vitamins
- excess stores in fatty tissue
- too much can be toxic
- Vitamins A, D, E, & K
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water soluable vitamins
- excess excreted in urine
- Vitamins C and B
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Minerals
- inorganic
- only needed in small amounts
- Ca, Fe, Mg
- body does not metabolize them, can be lost in sweat/urine
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4 stages of food processing
- ingestion
- digestion (mechanical and chemical)
- absorbtion
- elimination
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why is digestion necessary?
organisms need to convert food into smaller, soluable molecules that can be absorbed by cells
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ameba and paramecia
food vacuoles
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hydra
- gastrovascular cavity
- 1 opening, 2 way hole
- extracellular and intracellular digestion
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earthworm
- alimentary canal
- 2 openings, 1 hole
- tube within a tube
- extracellular digestion
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the human digestive system is an ____ canal
alimentary
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parts of the tube (human digestive system)
- mouth
- pharynx (throat, epiglottis)
- esophagus
- stomach
- small intestine (appendix- vestigial)
- large intestine
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process of digestion
- chewing- mechanical digestion, amalyse (salavia) - chemical digestion, breaks down starch
- food goes down esophagus- contractions (peristalsis) keep food down
- pepsin in stomach breaks down proteins (chemical digestion), churning (mechanical digestion)
- pancreatic juice neutalizes stomach acid before food enters the small intestine
- bile is secreted by the gallbladder, lipase is excreted from the small intestine (breaks down lipids/fats)
- large intestine absorbs water
- food is excreted
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function of the excretory system
- get rid of body wastes to maintain homeostasis
- urea from amino acids, excess water, CO2, Nitrogenous wastes
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kidneys
- remove waste products from blood
- maintain blood pH
- regulate water content of blood
- made up of renal medulla (inner) and renal cortex (outer)
- each functional unit is a nephron
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ureter
leaves each kidney and carries urine to bladder
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urinary bladder
stores urine before excretion
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kidneys (system)
- blood enters a nephron through an arteriole
- impurities are filtered out and emotied into the collecting duct
- purified blood exits the nephron through venule
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filtration
- takes place in glomerulus
- network of capillaries encased in upper end of nephron by the bownam's capsule
- the blood is under pressure and the walls of the bowman's capsule are permeable
- much of the fluid from the blood flows into the Bowman's capsule, called the filtrate (water, urea, glucose, salts, amino acids, and some vitamins)
- plasma proteins and red blood cells are too large to pass through capillary walls, and remain in the blood
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reabsorbtion
- kindeys siter all of the body's blood in aboyt 45 minutes
- not all filtrate is excreted, most gets reabsorbed into blood
- amino acids, fats, and glucose removed from filtrate by active transport
- 99% of water is reabsorbed
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urine formation
- after reabsorbtion, urine empties into a collecting duct concentrates in Loop of Henle
- urine then collected in urinary bladder and released through the urethra
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dilysis
- blood is removed and pumped through special tubing with tiny pores (acts as nephrons)
- pores allow salt and nitrogenous wastes to pass through
- purified blood returned to body
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parts of a nephron
- glomerulus
- bowmans capsule
- capillaries
- collecting duct
- loop of henle
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