Final (Chapters 14-16) Flashcards
What does the digestive system consist of?
- GI Tract (hollow tube)
- accessory organs
What does the GI tract consist of?
- Lumen (space within the tube
- Mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- rectum
- anus
What are the accessory organs?
- salivary glands
- liver
- gallbladder
- pancreas
What is the mucosa?
- innermost layer
- mucous membrane in contact with lumen
What is the sub-mucosa?
layer of connective tissue containing blood vessels, lymph vessels, and nerves
What is the muscularis?
two or three layers of smooth muscle responsible for movement and motility
What are sphincters?
thick muscular rings that separate some of the organs
How many layers of smooth muscle does the stomach have?
3
What happens during the Mechanical Processing and Movement stage of digestion?
chewing and mixing
What happens during the Secretion stage of digestion?
- fluid
- digestive enzymes and hormones
- bile, acid, alkali metals
What occurs during the Digestion stage of digestion?
- break down food to smallest absorbable units
- chemical and mechanical breakdown
What occurs during the Absorption stage of digestion?
- through mucosa
- into blood or lymph vessels
What occurs during the Elimination stage of digestion?
undigested material eliminated
Function of peristalsis?
propels food forward
Function of segmentation?
mixes food
Function of teeth?
bite and chew food
Types of teeth?
- incisors
- canines
- premolars
- molars
How many teeth do children have?
20
How many teeth do adults have?
32
Structure of the tooth?
crown and root
Function of tongue?
- positions and tastes food
- important for speech
What is the tongue made of?
skeletal muscle
What are the 3 salivary glands?
- parotid
- submandibular
- sublingual
What is saliva made of?
- mucin
- salivary amylase
- bicarbonate
- lysozome
What is the voluntary part of swallowing?
tongue pushes bolus of food into pharynx
What is the involuntary part of swallowing?
swallowing reflex
Function of pharynx?
common passageway for air and food
Function of epiglottis?
closes airway temporarily so food will not enter the trachea
How does food move through the esophagus?
peristaltic contractions
What happens to the food after going through the lower esophageal sphincter?
goes into the stomach
Function of stomach?
- food storage
- digest proteins
- regulate delivery of partially digested food to the small intestine
What does gastric juice contain?
- hydrochloric acid
- intrinsic factor
- mucus
- pepsinogen
Function of hydrochloric acid?
breaks down large bits of food (pH of 2)
Function of intrinsic factor?
absorb B12
Function of mucus?
protect stomach lining from acid
Function of pepsinogen?
begin breakdown of proteins (turns to pepsin when placed with acid)
Function of stomach contraction?
blend food and propel it forward
Where is the bolus heading after stomach contraction?
pyloric sphincter
What is chyme?
watery mixture of partially digested food and gastric juice that is delivered to the small intestine
How long does it take the stomach to empty?
2-6 hours
What happens in regards to digestion in the small intestine?
- neutralizes acid from stomach
- adds digestive enzymes and bile
- breaks down proteins, carbohydrates, and lipids
What happens in regards to absorption in the small intestine?
90% of food is absorbed here
What are the regions of the small intestine?
- duodenum (digestion)
- jejunum (absorption)
- ileum (absorption)
What increases the surface area in the small intestine?
mucosa adaptations
What are villi?
microscopic projections containing blood and lacteal capillaries
What are microvilli?
cytoplasmic projections of epithelial cells of the villi
Function of pancreas?
- exocrine functions
- secretes digestive enzymes and sodium bicarbonate
What are the digestive enzymes secreted?
- proteases
- pancreatic amylase
- lipase
Function of liver?
produces bile which emulsifies lipids
Function of the hepatic portal system of the liver?
drains blood from digestive tract to the liver
What are the metabolic functions of the liver?
- storage
- synthesis
- chemical processing
Function of gallbladder?
concentrates and stores bile
Function of large intestine?
- absorbs nutrients and water
- temporarily stores and eliminates waste
What is the structure of the large intestine?
- cecum, appendix
- colon (ascending, descending, transverse, sigmoid)
- rectum, anus
How are proteins and carbohydrates absorbed?
active transport
How are lipids absorbed?
broken down to fatty acids and then reassembled into triglycerides within epithelial cells
How is water absorbed?
osmosis
How are vitamins absorbed?
various ways
Regulation of the digestive system depends on what?
volume and content of food
How does the nervous system affect the digestive system?
stretch receptors in the stomach can cause reflexes to increase peristalsis and secretion of gastric juice
Function of gastrin?
stimulates release of gastric juice (secreted by stomach)
Function of secretin?
stimulates pancreas to secrete water and bicarbonate
Function of cholecystokinin?
- signals pancreas to secrete digestive enzymes
- signals gallbladder to release bile
What is a healthy diet?
- variety of foods
- plenty of fruits, vegetables, and whole grains
- low in cholesterol and saturated fat
- sugar, salt, an alcohol in moderation
What percent of carbohydrates should be our caloric intake?
45-65%
What are simple carbohydrates?
sugar
What are complex carbohydrates?
- starch
- glycogen
- fiber
What are saturated fats?
-meat
-dairy
-palm kernel oil
(tends to raise LDL “bad cholesterol)
What are unsaturated fats?
-plant sources, olive, safflower, corn, canola oils, certain cold water fish
(tend to lower LDL and reduce risk of heart disease)
What is trans fat?
-hydrogenated vegetable oils
raises LDL
How many amino acids are there?
20
12 made by the body; 8 must be digested through food
What do complete proteins contain?
all 20 amino acids (incomplete lack 1 or more)
What are fat soluble vitamins?
-A, D, E, and K
absorbed with fats and stored in adipose tissue
What are water soluble vitamins?
- stored only briefly
- must be consumed on a regular basis
What are the roles of minerals?
- ions in blood plasma and cell cytoplasm
- chemical structure of bone
- nerve and muscle activity
Function of the urinary system?
excretes nitrogenous wastes, excess solutes, and water
Function of kidneys?
- regulates body water levels
- regulates nitrogenous wastes and other solutes (made into urea then transported to kidneys)
What solutes are regulated by the kidneys?
- sodium chloride
- potassium
- hydrogen ions
- creatine
- calcium
Function of ureters?
transport urine from kidney to bladder
Function of urinary bladder?
stores urine
Function of urethra?
carries urine from body
Function of nephrons?
remove approximately 180 liters of fluid from the blood daily and return most of it minus wastes that are excreted
Function of the glomerular capsule?
cup like end of nephron tubule surrounding glomerulus where filtration occurs
Parts of the nephron?
- glomerular capsule
- proximal tubule
- loop of Henley
- distal tubule
- collecting duct
What are the three steps to form urine?
- Glomerular Filtration
- Tubular Reabsorption
- Tubular Excretion
What occurs during glomerular filtration?
-movement of protein-free solution of fluid and solutes from blood into the glomerular capsule
-large volume filtration; highly selective
(impermeable to large proteins; filtration is driven by high blood pressure
What occurs during tubular reabsorption?
return of most of the fluid and solutes into the blood
What occurs during tubular secretion?
addition of certain solutes from the blood into the tubule
How do kidneys respond to excess water?
excreting it
distal tubule impermeable to water; NaCl is reabsorbed without reabsorption of water
How do kidneys respond to insufficient amounts of water?
- conserve it
- mediated by ADH from the posterior pituitary gland; the ADH increases permeability of collecting ducts to water
What is the micturition reflex?
-responds to stretch receptors in bladder wall
internal urethral sphincter=smooth muscle; external urethral sphincter=skeletal muscle
What can override the micturition reflex?
brain (voluntary control becomes harder as the bladder gets full)
How does the kidneys maintain homeostasis?
- maintain water balance
- aldosterone, renin, and ANH help maintain salt balance to control blood volume
- maintain acid base balance and blood pH
- regulate blood cell production by erythropoietin
- activate inactive form of vitamin D
Function of testes?
produce sperm
Function of scrotum?
maintains testes at a slightly lower temperature
Function of the seminiferous tubes?
produce sperm
Function of the ductus deferens?
transports sperm to where it becomes the ejaculatory duct
What is the route sperm takes through the reproductive system?
- seminiferous tubules
- epididymis
- ductus deferens
- ejaculatory duct
- penis
Function of seminal vesicles?
secrete fructose (energy for sperm) and most of the seminal fluid
Function of prostate gland?
secretes watery alkaline fluid to raise vaginal pH
Function of bulbourethral gland?
- secretes lubricating mucus
- cleanses urethra
What does meiosis accomplish?
- halves chromosome number
- shuffles genetic info so that each egg and sperm combination is different
What is testosterone?
steroid hormone produced by interstitial cells in testes
Function of testosterone?
- controls growth and function of male reproductive tissues
- stimulates aggression, sexual behavior, and secondary sexual characteristics
- determines rate of sperm formation
Hormones that regulate testosterone and sperm production?
- Gonadotropin
- LH
- FSH
- Inhibin
Function of Gonadotropin?
releases GnRH from hypothalamus
Function of LH?
stimulates production of testosterone
Function of FSH?
may enhance sperm formation with sertoli cells
Function of inhibin?
produced by sertoli cells and inhibits secretion of FSH
Function of ovaries?
release oocytes and secretes estrogen and progesterone
Function of oviduct?
-leads from ovary to uterus
Function of uterus?
fertilized egg grows and develops here
Function of endometrium?
- supports fertilized egg
- part sloughs off
Function of myometrium?
expands during pregnancy and constricts during labor (smooth muscle)
Function of cervix?
- permits sperm to enter the uterus
- allows fetus to exit during birth
Function of vagina?
organ of sexual intercourse and birth canal
What are the external genitalia?
- labia majora and minora
- clitoris
What is the ovarian cycle?
series of changes in ovaries associated with oocyte maturation (controlled by FSH and LH)
What is the uterine cycle?
changes in the endometrial lining of the uterus (controlled by estrogen and progesterone)
What does chorine tissue do during pregnancy?
secretes hCG
What does hCG cause during pregnancy?
corpus luteum continues to produce estrogen and progesterone for another 9-10 weeks until the placenta can take over
What does increased estrogen and progesterone cause?
prevents ovulation during pregnancy
