6.2 Digestive System and Urinary System U6 Flashcards
What is digestion?
The process of breaking down food into molecules the body can use
What does the digestive system do?
takes in food, breaks it down into molecules small enough for the body to absorb, and gets rid of undigested molecules and waste.
What is the path of the digestive system?
begins at the mouth and winds through the body to the anus.
What 6 things are included in the digestive process?
Ingestion
Mechanical digestion
Propulsion
Chemical digestion
Absorption
Defecation
What is mechanical digestion?
Chewing
Churning in stomach
What is propulsion?
Movement of food via swallowing and peristalsis
What is chemical digestion?
Carbohydrates are broken down into simple sugars; proteins are broken down into amino acids; fats are broken down into fatty acids and alcohols
What is absorbtion?
Nutrient molecules enter cells, blood vessels, and lymph vessels
What is defecation?
Elimination of indigestible substances from the body as feces
What do teeth do?
rip and chew food into shreds
What are the three type of teeth?
Incisors Canines Molars
What are incisors?
biting and cutting food
What are canines?
shred food
What are molars?
crush and grind food
What does the tounge do?
Helps with food movement & swallowing
What do the salivary glands produce?
produce saliva
What 3 glands secrete saliva?
Parotid, Sublingual, submandibular
What do the enzymes and mucous in saliva do?
aids in digestion and the molding of food to be swallowed
What is amylase?
enzymes break down carbohydrates
What does mucous do?
provides lubrication
What is bolus?
At this point, you have the formation of a bolus (food that’s been chewed/mixed up with saliva/amylase)
When does bolus trigger a swallowing response?
after passing the pharynx.
What is the pharynx?
Passageway for food & air
What is the epiglottis?
Prevents food or water from entering the trachea. The action of swallowing moves the epiglottis (flap of tissue)over the opening of the trachea
What is the trachea?
the tube that leads to the lungs.
What is the esophagus?
is a tube that connects the mouth to the stomach.
What are peristaltic contractions?
Food is pushed down by successive rhythmic waves of smooth muscle contraction
What is the lower esophageal sphincter?
Sphincter prevents stomach acid from entering the esophagus. Bolus exits the esophagus and enters the stomach through a muscular valve called a sphincter (lower esophageal sphincter).
What does the stomach do?
mechanically breaks down food and chemically breaks down proteins (2 to 6 hours).
What does pepsin do?
breaks down proteins into amino acids
What does HCI do?
activates enzymes, kills bacteria, & lowers the pH
What does the mucosal barrier do?
consisting of mucus, epithelial cells, and bicarbonate ions that neutralize stomach acid protects the lining of the stomach from gastric acids.
Does mechanical digestion occur in the stomach, if so, how?
yes, peristaltic waves
what is chyme?
After digestion in the stomach, the bolus becomes chyme!
How are gastric ulcers formed?
Erosion of the stomach wall resulting in ulcers
Commonly caused by bacteria (Helicobacter pylori) and aggravated by hypersecretion of HCL, hyposecretion of mucus
What enzymes does the pancreas produce?
Lipase (fats), Amylase (carbohydrates), Protease (proteins)
What does the pancreas do?
Produces many important digestive enzymes
What does the gallbladder do?
Stores bile produced by the liver, which helps digest fasts!
Where are the enzymes released to by the pancreas and gallbladder?
into the beginning portion of the small intestine
What is the pyloric sphincter?
between stomach and small intestine opens and allows chyme to pass!
What are the three sections of the intestine?
duodenum, jejunum, ileum
What does the duodenum do?
joins stomach at the pyloric sphincter and receives secretions from the liver & pancreas to aid in digestion
Where does the Illeum join?
joins the large intestine
Where does most chemical digestion occur?
small intestine
The small intestine recieves what from the liver?
Receives enzymes and bile
What do villi and microvilli do?
These structures increase surface area available for absorption (nutrients & water)
What lines the intestine?
villi and microvilli
What are the three main segments of the large intestine?
ascending, descending, transverse
What enters the large intestine?
Indigestible materials
How does the indigestible material dry out?
Dries out by absorbing remaining water
What do most of the colons content include?
Dead cells
Mucus
Digestive secretions
Bacteria
Yeast
What is the rectum?
is the final segment of the colon.
What does peristalsis do with the rectum?
moves solids into the rectum.
What does the urinary system do?
Filters blood to remove waste (& stores/excretes urine)
Regulates blood pressure, volume, and RBC production
What are the two parts of the urinary system?
Upper and Lower Urinary Tracts
What does the Upper Urinary Tract contain?
Kidneys, Ureters
What does the Lower Urinary Tract contain?
Bladder, Urethra
How does blood travel through the kidneys?
lood enters via renal arteries and exits via renal veins
What is a nephron?
Functional unit of kidney
How many nephrons are in a kidney?
1+ million nephrons per kidney!
How is urine created?
- Blood enters the kidney through the renal artery, which branches into capillaries. When blood passes through capillaries of the glomerulus (cluster of blood vessels) of a nephron, blood pressure forces some of the water and dissolved substances in the blood to cross the capillary walls into Bowman’s capsule.
- The filtered substances pass to the renal tubule of the nephron. In the renal tubule, some of the filtered substances are reabsorbed and returned to the bloodstream. Other substances are secreted into the fluid.
- The fluid passes to a collecting duct, which reabsorbs some of the water and returns it to the bloodstream. The fluid that remains in the collecting duct is urine.
What are the Uterers?
Narrow tubes carry urine from kidneys to bladder
Via smooth muscle/peristalsis, gravity
What is the bladder?
Involuntary muscle movements send signals, makes control of urination conscious
Internal Sphincter
External Sphincter
Urethra
What is the internal sphincter?
INVOLUNTARY
What is the external sphincter?
VOLUNTARY
Waits to relax
What is the urethra?
Tube urine is expelled through
