Lecture Test One Part One Flashcards
Why is temperature regulation so important?
An imbalance in temperature could cause reactions to enzymes
What area of the brain regulates temperature?
hypothalamus
What is the normal core body temperature?
99.6 degrees
Humans are classified as ________ which means they are able to regulate their body temperature.
homeotherms
How is temperature maintained?
a balance between heat gained and heat lost
What is hyperthermia?
heat gain exceeds heat lost
What temperature will hyperthermia set in?
technically 100 degrees but enzymes will not be affected until temperatures of more than 103
What are some common causes of hyperthermia?
exercise
environment
fever
What will hyperthermia cause?
heat stroke
heat exhaustion
what are the symptoms of heat exhaustion?
flushed, sweating profusely, nasea, dizzy. Patient will survive.
What are the symptoms of heat stroke?
flushed, vomiting, comatose, patient has stopped sweating
A fever is caused by the release of
pyrogens
Pyrogens from WBCs increase the release of
prostaglandins
Prostaglandins affect the
hypothalamus to raise the set temperature.
In theory, prostaglandins reset
the thermostat
Aspirin is an
antiprostaglandin
What does aspirin do?
It prevents the thermostat from resetting. It will make you feel better but will keep the invader from leaving
What is hypothermia?
heat loss exceeds heat gain
What are some common causes of hypothermia?
environment
anesthesia
At what temperature will hypothermia set in?
95 degrees or lower.
What happens to enzymes during hypothermia?
It slows them down but does not denature them as in hyperthermia
What are some symptoms of hypothermia?
decreased heart rate, decreased respiratory rate decreased metabolism vasoconstriction coma death
what is the metabolic rate?
total amount of energy produced and used by the body per unit of time.
what does the metabolic rate compare?
ATP use and production
what are the three locations for energy use?
basal metabolic rate
thermic affect of food
muscle acttivity
what is basal metabolic rate?
energy that keeps resting body functioning. most energy is used for this
what is thermic effect of food?
energy needed for digestion of food. least amount of energy used for this
what is muscle activity?
energy used for movement of skeletal muscles
What will happen if energy intake is higher that enrgy output?
weight gain
How many calories does an average 154lb male need daily?
2700 calories
How many calories does an average 120 lb woman need daily?
2000
what are the two ways to produce ATP?
anaerobically
aerobically
What is anaerobic respiration?
no oxygen needed
no mitochondria
glycolysis followed by fermentation
how many ATPs does anaerobic respiration produce?
2 ATPs
What is aerobic respiration?
needs oxygen
needs mitochondria
glycolysis, Krebs, ETC
How many ATPs does aerobic respiration make?
38
All energy is derived from
the sun
ATP input comes from
the food we eat
What is digestion?
The breakdown of large food molecules into smaller molecules
What are the six different activities that the digestion system carries out?
Ingestion Secretion Motility Digestion (mechanical and chemical) Absorption Elimination
What is ingestion?
The intake of food
What is secretion?
cells within the digestive system will release substances that aid in digestion
What are some different types of secretion?
7 liters of water, enzymes, acids, mucus
what is motility?
movement of food from one tract to the next
what is peristalsis?
rhythmic, involuntary muscle contractions of the gastrointestinal tract
What is mechanical digestion?
movements of the GI tract that aid in the breakdown of the food.
What are some examples of mechanical digestion?
chewing, peristalsis, mixing
what is chemical digestion?
chemical reactions that breakdown organic molecules into smaller ones using enzymes
what is an enzyme?
substance that increases the rate of chemical reactions without changing themselves
each enzyme will have its own
substrate
enzymes work best when they are at
optimal temperature and optimal pH
what is absorption?
passage of digested food from the GI tract into vessels (Blood and lymph)
what is the purpose of absorption?
so food molecules can be transmitted to and used by body cells
what is elimination?
removal of undigested substances from the GI tract.
What are the 2 main groups of the digestive system?
GI tract
accessory structures
what is the GI tract?
the organs that the food actually pass through
what are the organs of the GI tract?
mouth pharynx esophagus stomach small intestine large intestine
What is the length of the GI tract?
25-28 feet
what is the total transit time of the digestive system?
24-36 hours
what are accessory structures?
they aid in digestion but the food does not go through them
what are some examples of accessory structures?
teeth tongue salivary glands liver gallbladder pancreas
What are the histology layers of the digestive tract?
tunica mucosa
tunica submucosa
tunica muscularis
tunica serosa
What is the mouth
opening of the digestive tract from lips to pharynx
what are the two compartments of the mouth?
vestibule
oral cavity
what is the vestibule?
area of the mouth between the cheeks and the gums (gingiva)
what is the oral cavity?
lined by hard and soft palate superior, uvula posterior, teeth anterior
what are the two sets of teeth that humans have
primary/deciduous
secondary/permanent
why are teeth important?
mechanical digestion and speech
what are the four different types of teeth?
incisors
canines
premolars
molars
The deciduous teeth enter the gingiva beginning at
6 months
When are deciduous teeth usually complete?
age 2
when do permanent teeth begin forming?
age 5 or 6
The tongue is mostly composed of
skeletal muscle
The tongue is attached to the bottom of the mouth by the
lingual frenulum
what are the functions of the tongue?
movement of food
taste
speech
what part of the tongue is important to taste?
anterior portion
what are the 3 major pairs of salivary glands?
parotid gland
submandibular gland
sublingal glands
What are the parotid glands?
largest of the glands they produce a serous secretion
where are the parotid glands found?
anterior to the ears
Where do the parotid secretions enter?
over the 2nd upper molar
What pathology is associated with the parotid glands?
the mumps, a viral infection that leads to swelling of the glands
what are the submanidibular glands?
found under the mandible they produce a serous secretion
where do the submandibular secretions enter?
adjacent to the lingual freenulum
what are sublingal glands?
found under the tongue producing a mucus secretion
where does the sublingual secretion enter?
numerous locations
What are the functions of the salivary glands
secretion of saliva
what type of glands are the parotid, submandibular and sublingual glands?
exocrine glands
Saliva is 99.5% water and is under control by the
nervous system
what are the functions of saliva
dissolving food lubrication stimulation of tastebuds bacterial prevention contains enzymes important in digestion of carbs
taste buds are a type of
chemioreceptor
How does saliva prevent bacteria to enter the mouth?
lysozymes
What is the mechanical digestion of the mouth?
mastication
what is the purpose of mastication?
to increase surface area allowing more digestive enzymes to come into contact with the food
what is the result of the actions of the teeth and the tongue?
a bolus is formed
what is a bolus?
a soft, round ball of food
What chemical digestion occurs in the mouth?
salivary amylase
what is salivary amylase?
a special enzyme that begins to break down carbohydrates
Salivary amylase breaks:
polysaccharides into disaccharides
salivary amylase is primarily produced by
submandibular glands
what is the optimal temperature for salivary amylase
98.6
what is the optimal pH of salivary amylase?
7
what is the optimal pH of lingual lipase?
5
does the mouth have ingestion?
yes
does the mouth have secretion
yes, saliva
does the mouth have motility?
yes mastication
what chemical digestion occurs in the mouth?
salivary amylase
what mechanical digestion occurs in the mouth?
mastication
does absorption occur in the mouth?
no
does elimination occur in the mouth?
no
what occurs after the bolus is formed?
deglutition
what is deglutition?
swallowing
when deglutition occurs the bolus is pushed:
into the pharynx with the help of peristalsis.
After the bolus enters the pharynx it continues to
the esophagus
What covers the larynx?
epiglottis
what is the function of the epiglottis?
prevents food and water from entering as the bolus passes
does ingestion occur in the pharynx?
no
does secretion occur in the pharynx?
no
does motility occur in the pharynx?
yes–deglutition
what mechanical digestion occurs in the pharynx?
deglutition
what chemical digestion occurs in the pharynx?
salivary amylase
does absortion occur in the pharynx?
no
does elimination occur in the pharynx?
no
what is the esophagus?
a collapsible, muscular tube that connects the pharynx to the stomach
where is the esophagus located?
the mediastinum of the thorax
As the bolus moves from the pharynx into the esophagus it will pass through a sphincter called
the upper esophageal sphincter
what is a sphincter?
circular muscle that can constrict an opening regulating movement of the digestive contents through the GI tract
the esophagus will go through the
diaphram
what is the diaphragm?
a large muscle that seperates the thoracic cavity at an opening called the esophageal hiatus
what is a hiatal hernia?
when the esophageal hiatus causes a weakness in the diaphragm and portions of abdominal organs protrude into the thoracic cavity
the esophagus eventually narrows and the bolus passes through the _________ to the stomach
lower esophageal sphincter or cardiac sphincter
what is peristalsis?
involuntary smooth muscle contractions that push food down
peristalsis is under control by the
medulla oblongata
does the esophagus have ingestion
no
does the esophagus have secretion
mucus
does the esophagus have motility?
peristalsis
what chemical digestion occurs in the esophagus?
salivary amylase
what mechanical digestion occurs in the esophagus>
peristalsis
does absorption occur in the esophagus?
no
does elimination occur in the esophagus?
no
the stomach is shaped like a
j
where is the stomach located?
under the diaphragm primarily on the left side
what are the four areas of the stomach?
cardiac region
fundus
body
pylorus
where is the cardiac region of the stomach?
surrounds lower esophageal sphincter
what is the fundus?
the rounded portion of the stomach
what is the body portion of the stomach?
large central portion
where is the pylorus?
most inferior portion of the stomach, right around the pyloric sphincter
what does the pyloric sphincter connect?
the stomach and the small intestine
what is the histology of the stomach?
arranged in large folds called the rugae
when empty, the stomach is the size of
a clenched fist
the stomach can hold up to
4 liters
what do mixing waves do?
they push the bolus around causing it to be mixed with digestive enzymes
The mixing waves eventually turn the bolus into
chyme
mixing waves are a type of
mechanical digestion
the stomachs pH is usually around
2
How much secretion occurs in the stomach?
2-3 liters
why is the stomach so acidic?
the secretion of hydrochloric acid by parietal cells
Hydrochloric acid is important because
it maintains optimal pH for digestive enzymes and kills bacteria
Hydrochloric acid deactivates
salivary amylase due to the change of pH
what is pepsin?
an enzyme that is secreted into the stomach lumen by chief cells
what is the function of pepsin?
digestion of proteins
how does pepsin digest proteins?
reduces the length and changes the shape of amino acid chains
pepsin is secreted in the inactive form called
pepsinogen
what activates pepsinogen into pepsin?
the presence of hydrochloric acid
what is gastric lipase?
enzyme produced by chief cells that digests lipids
what is the optimal pH of gastric lipase?
5-6
what is mucus?
alkaline substance that is produced by mucous cells in the stomach lining
what is the function of mucus?
moistens the bolus and offers protection to the lining of the stomach
what is gastrin?
hormone of the stomach (not an enzyme) produced by endocrine cells
what is the function of gastrin?
relaxation of the pyloric sphincter after a meal and release of HCL and pepsinogen
what is histamine?
hormone produced by endocrine cells that affects H2 receptors on parietal cells
what is intrinsic factor?
a glycoprotein that is secreted by parietal cells
what is the function of intrinsic factor?
allows for the absorption of B12 needed for production of RBCs.
Can people live without a stomach?
yes but they needed to eat smaller meals more frequently.
what is the biggest problem with people who have no stomach?
anemia
what is anemia?
a decrease of RBCs
How is anemia treated??
B12 shots taken exogenously
where do most secretions come from?
the stomach
parietal cells are responsible for
hydrochloric acid production
intrinsic factor
what are chief cells responsible for?
pepsinogen
gastric lipase
what are endocrine cells responsible for
histamine and gastrin
what are mucous cells responsible for?
making mucus
Are carbs digested in the stomach?
no only proteins
what are the three phases to stomach digestion?
cephalic phase
gastric phase
intestinal phase
what is the cephalic phase?
the smell and thought of food
chewing (small quantity of histamine and gastrin are released) (HCL/pepsin)
what is the gastric phase?
the stomach expands and activates a mechanoreceptor.
what is released during the gastric phase?
a large amount of histamine and gastrin producing a large amount of HCL and pepsin
what is the intestinal phase?
small intestine. chyme has now left the stomach and stomach has turned off. small intestine turns on.
what is released in the intestinal phase?
secretin
cholecystokinin
gastric inhibitory polypeptide
most absorption occurs in the
small intestine
what things can go through the stomach wall?
water
electrolytes
some drugs
alcohol
within 2-6 hours after eating the stomach has emptied its contents into the
duodenum though the pyloric sphincter
does ingestion occur in the stomach?
no
does secretion occur in the stomach?
2-3 liters mostly mucus
does motility occur in the stomach?
`peristalsis and mixing waves
does mechanical digestion occur in the stomach?
peristalsis and mixing waves
does chemical digestion occur in the stomach?
pepsin and gastric lipase
does absorption occur in the stomach?
water, electrolytes, some drugs and alcohol
does elimination occur in the stomach?
no
what are the three regions of the small intestine?>
duodenum
jejunum
ileum
what are the accessory structures of the small intestine?
pancreas
liver
gall bladder
where does majority of digestion occur
small intestine
As chyme leaves the stomach it passes through the duodenum and comes in contact with material from
pancreas
gall bladder
liver
the pancreas is both
exocrine and endocrine organ
the endocrine portion of the pancreas is responsible for
homeostasis
the exocrine portion of the small intestine is responsible for
digestive enzymes
________ make up the exocrine glands of the pancreas
acini cells
acini cells secrete
pancreatic juice that contains many digestive enzymes
the pancreatic juices will be secreted into the
pancreatic duct and the accessory duct
what is pancreatic juice?
clear, colorless secretion composed of water, electrolytes, and enzymes
what is the pH of pancreatic juice?
7.2-8.2
what is significant of the pH of pancreatic juice?
stops the action of pepsin and activates gastric lipase
what enzymes are in pancreatic juice?
pancreatic amylase trypsin chymotrypsin procarboxypeptidase pancreatic lipase ribonucleases deoxyribonuclease
what is pancreatic amylase?
continues digestion of carbohydrates that was started in the mouth
what is the function of pancreatic amylase?
turns polysaccharides into disaccharides
what is trypsin, chymotrypsin and procarboxypeptidase?
enzymes secreted in inactive form and are activated by enterokinase
what is pancreatic lipase?
continues the digestion of lipids
what is the function of ribonucleases and deoxyribonucleases?
digestion of nucleic acids
what is pancreatitis?
inflammation of the pancreas. It overproduces enzymes causing damage to DNA. The pancreas begins eating itself
what is the treatment for pancreatitis?
no eating or drinking
what are the endocrine functions of the pancreas?
secretes the hormones glucagon and insulin
what are glucagon and insulin important for?
maintaining the level of glucose in the blood
where are glucagon and insulin produced?
islet of langerhans
what is the islet of Langerhans composed of?
alpha and beta cells
what are alpha cells?
produce glucagon when glucose levels in blood decrease
how does glucagon work?
travels to the liver and causes glycogenolysis. Glucose is released into the blood maintaining homeostasis
what is glycogenolysis?
breakdown of glucogen into glucose
what are beta cells?
they produce insulin when blood glucose levels increase.
how does insulin work?
it travels to the liver and causes glycogenesis. It also increases the permeability of the cell membrane to glucose allowing passage of glucose into the cell and out of the blood
what is glycogenesis?
converting glycogen into glucose
what is diabetes mellitus?
inability of the body to produce insulin, produce active insulin, or failure of the receptors to work properly.
what is the diagnosis of diabetes?
fasting hyperglycemia, glucosaria
what are the symptoms of diabetes>
PU/PD/PP
what is PU?
polyuria–constantly urinating
what is PD?
polydipsia–constantly drinking
what is PP?
polyphagia–constantly eating
what are the three types of diabetes?
type 1
type 2
gestational
what is type one diabetes?
juvenile onset
insulin dependent
diagnosed in children
what is type 2 diabetes?
adult onset
associated with the obese
non insulin dependent
a resistance to insulin
what is gestational diabetes?
pregnancy
good prenatal care can fix it
Where is the liver located?
under the diaphram
what are the four lobes of the liver?
right
left
caudate
quadrate
what holds the liver in place?
falciform ligament (attaches to the diaphragm
what is the liver composed of
heptatic lobules containing hepatocytes
what are the spaces inside the liver called?
sinusoids
How does blood flow into the sinusoids?
blood vessels
The sinusoids are lined with
kupffer cells
what are kupffer cells?
phagocytic cells that destroy old RBCs, WBCs, bacteria, viruses and toxic materials
what are the main functions of the liver?
carbohydrate metabolism
lipid metabolism
protein metabolism
production of bile
what are some minor functions of the liver
detoxification
storage
protection
synthesis
what is carbohydrate metabolism of the liver?
maintains the normal blood glucose level with help of glucagon and insulin
The liver is the main site of
glycogenesis and glycogenolysis
what is lipid metabolism of the liver?
storage of triglycerides and production of cholesterol
what is protein metabolism of the liver?
converts ammonia into urea which is excreted by the kidneys
without the liver a person would
die in a few days because of ammonia poisoning
what is bile?
a greenish-brown substance that contains bile salts, bile pigments, cholesterol and fats
bile is produced by
the liver
bile is stored in the
gallbladder
what is the function of bile?
emulsifies fats when released into the duodenum. allows bilirubin to pass out of the body, neutralizes pH in the deuodenum along w/pancreatic juices
what gives feces its brownish color?
bile
a large portion of bile is reabsorbed in
the small intestine
what is bilirubin?
waste product of hemoglobin from old red blood cells
what is detoxification of the liver?
removal of some drugs and alcohol from the liver
what is stored in the liver?
glycogen, vitamins, minerals and iron
what is the protective function of the liver?
phagocytosis by kupffer cells
what do kupffer cells phagocytize in the liver?
old RBCc and WBCs
what does the liver synthesize?
albumin, heparin and clotting factors are all made in the liver
albumin attracts
water
what is jaundice?
yellowing of the skin and eyes
what is the cause of the yellowing of the eyes?
a buildup of bilirubin
what is cirrhosis?
widespread destruction of the liver cells by viral infections, drugs and alcohol
with cirrhosis, what happens to liver cells?
they die and aren’t reproduced as fast as scar tissue does
what is hepatitis?
inflammation of the liver. five different types
what is hepatitis A?
fecal oral transmission, vaccines available and usually does not turn into cirrhosis
what is hepatitis B?
transmitted by bodily fluids. most common of hep viruses
vaccine available
what is hepatitis C?
transmitted through bodily fluids. healthcare workers at most risk
what is the treatment for hepatitis c
prednisone and interferon
what is the gallbladder?
sac-like structure that is under the inferior surface of the liver
what does the gallbladder do?
stores and concentrates bile
what are gallstones?
bile becomes so concentrated that it crystallizes and blocks the ducts of the gallbladder
what causes gallstones?
cholesterol precipitation
what is the treatment for gallstones?
surgery
medication
sound waves
The liver has hepatic ducts that combine to form
common hepatic duct
the common hepatic duct combines with the gallbladders cystic becoming the
hepatopancreatic ampulla
the hepatopancreatic ampulla empties into the duodenum through an opening called
major duodenal papilla
the _____ opens allowing contents to enter the duodenum
sphincter of oddi
the accessory pancreatic duct empties into the duodenum through the
minor duodenal papilla
what is the stimulus to empty the gallbladder?
chloecystokinen
When no digestion is occuriing, the major duodenal ampula is closed and the released bile backs up into
the cystic duct into the gallbladder where it is stored
the major stimulus for contraction of the gallbladder and relaxation of the ampulla is
chloecistokinen
what is chloecistokinen?
intestinal hormone released when fatty chime enters the duodenum
The small intestine is the major site for
absorption and digestion
what are the three sections of the small intestine?
duodenum
jejenum
ileum
what is the largest portion of the small intestine?
ileum
the ileum contains lymphatic tissue called
peyers patch
where in the ileum is the peyers patch found?
submucosa
the ileum joins the small intestine at the
ileocecal valve
what is total transit time for the small intestine?
3-5 hours
where does 90% of absorption occur?
small intestine
why is the small intestine well suited for absorption?
increased surface area
what are plicae circularis?
large folds found in the walls of the small intestine similar to rugae of the tongue
the surface of the small intestine is lined with
villi
what are villi?
finger-like projections that extend into the lumen
what is the function of villi?
to increase surface area
On the surface of the small intestine lumen there are
microvilli
Microvilli are referred to as
the brush border
what mechanical digestion occurs in the small intestine?
segmentation
peristalsis
what is segmentation?
localized contractions that mix the chime with the digestive juice
what chemical digestion occurs in the small intestine
the brush border enzymes
what are the brush border enzymes>
disaccharidases
peptidases
what are disaccaridases responsible for?
finishing the digestion of carbohydrates by breaking down disaccharides into monosaccharides
what are some examples of disaccharidases?
maltase
lactase
sucrase
what is lactose intolerance?
individual fails to produce lactase and cannot digest lactose
what are the symptoms of lactose intolerance?
gas cramping diarrhea pain fluid retention
what are peptidases?
enzymes that finish the digestion of proteins down into amino acids
carbohydrates are absorbed as
monosacharides
how are carbohydrates absorbed?
enter the free end of the epithelial cells, pass through the cytoplasm, pass into a blood capillary and finally enter the hepatic portal vein. From there, they go to the liver and then to the rest of the body
proteins are absorbed as:
amino acids
how are proteins absorbed>
they follow the same routes as carbohydrates
nucleic acids are absorbed as
nucleotides
how are nucleic acids absorbed?
the same path as proteins and carbohydrates
lipids are absorbed as
fatty acids
how are lipids absorbed?
fatty acids diffuse from the lumen of the small intestine into the free end of the epithelial cells, go through the basal side and finally pass into a lacteal of the villus
what is a lacteal?
a vessel of the lymphatic system that absorbs fat
from the lacteal, what happens to the fat?
becomes part of the lymph and will finally pass into the bloodstream.
Fat does not go through the
hepatic portal vein
most water reabsorption happens in the
small intestine
how much water enters the small intestine daily?
9 liters
where does most of the water that enters the small intestine come from?
GI secretions
after passing through the small intestine, chime is ready to go through the
ileococal sphincter into the large intestine
does ingestion occur in the small intestine?
no
does secretion occur in the small intestine?
mucus and digestive enzymes
does motility occur in the small intestine?
peristalsis and segmentation
does mechanical digestion occur in the small intestine
peristalsis and segmentation
does chemical digestion occur in the small intestine?>
disaccharidases and peptidase
does absortion occur in the small intestine?
YES
Does elimination occur in the small intestine?
no
what is the transit time of the large intestine?
the longest at 18-24 hours
externally, what gives the large intestine its segmentated appearance?
haustra
what are haustra?
series of pouches
what are the different sections of the large intestine?
cecum
colon
rectum
anal canal
