Exam 3 - Obesity & Digestive system Flashcards
What are the 2 classifications of adipose tissue?
- brown
2. white
What kind of adipose comprises most adipose in the body?
white adipose tissue (WAT)
What kind of stores are involved with WAT?
visceral and subcutaneous
What kinds of cells does WAT contain?
macrophages, mast cells, neutrophils, fibroblasts, endothelial cells, blood vessels nerves, and precursor adipocytes
What does WAT store?
excess fat
What 2 things help metabolize fat in WAT?
- estrogen
2. estrogen receptors
What kind of adipose tissue is rich in mitochondria?
brown adipose tissue (BAT)
What makes BAT brown?
iron
What 4 things stimulate BAT to rapidly generate heat through the activation of uncoupling protein 1?
- exposure to cold
- activation of the sympathetic nervous system
- catecholamines
- activation of triiodothyronine
How do neonates generate body heat?
from Bat located in the inter scapular and perirenal regions
BAT is common in which people? in which areas?
lean persons in…
- neck
- supraclavicular axillary
- paravertebral regions
- perirenal regions
What does BAT have an inverse relationship with?
BMI and age
What emerges within WAT with chronic exposure to cold, exercise, and exposure to synthetic ligand of peroxisome proliferator-activated receptor-y
bAT (brown in white)
Excess what contributes to obesity?
WAT (white adipose tissue)
What does WAT contribute to?
regulation of energy homeostasis
define obesity
increase in body fat mass
what is a major cause of morbidity, death, and increased care costs?
obesity
What is a BMI value for adults with obesity?
> 30 kg/m2
What is a BMI value for children with obesity?
> or equal to age and sex-specific 95th percentile of the growth charts in children
What are the leading causes o death associated with obesity
- CV disease
- type 2 diabetes mellitus
- cancer
what is the cellular basis of obesity?
adipocyte
what are the molecules that stimulate eating?
orexins
define orexin
a peptide family that act as neurotransmitters for stimulating eating
What are molecules that inhibit eating?
anorexins
what does the arcuate nucleus regulate?
regulates food intake and energy metabolism in hypothalamus
What do neurons with the ARC promote?
- appetite
- stimulate eating
- decrease metabolism
What does the hypothalamus control?
- reward
- pleasure
- memory
- addictive behavior
What is visceral obesity also known as?
intraabdominal, central, or masculine obesity
What is the distribution of body fat like with visceral obesity?
it is localized around the abdomen and upper body.
What is peripheral obesity also known as?
glutealfemoral, feiminine, or subcutaneous obesity
What is the distribution of body fat like with peripheral obesity?
It is exztraperitoneal and distributed around the things and buttocks and through the muscle.
What shape is visceral obesity?
apple
What shape is peripheral obesity?
pear
What is considered overweight in terms of BMI?
greater than 25 kg/m2
What are 3 things to correct with obesity?
- metabolic abnormalities
- weight-reduction diets
- exercise programs
What is the most effective treatment for obesity?
combination of weight reduction and exercise
What are 2 things that are critical with obesity?
- self-motivation
2. support systems
What are three psychiatric disorders related to a distorted body image with a desire for thinness and a fear of fatness that results in extreme restrictions in eating habits?
- anorexia nervosa
- bulimia nervosa
- binge eating disorder
What are 3 short term problems associated with starvation?
- glycogenolysis
- gluconeogenesis
- leads to ketosis and acidosis
define glycogenolysis
splitting of glycogen into glucose
define gluconeogenesis
formation of glucose from noncarbohydrate molecules
What are 2 long term problems associated with starvation?
- marasmus
2. kwashiorkor
What does treatment involve with starvation?
adequate ingestion of appropriate nutrients
What is anorexia of aging?
decrease in appetite or food intake in older adults
What is anorexia of aging due to
- Reduced energy needs
- Waning hunger
- Diminished sense of taste and smell
- Decreased production of saliva
- Altered GI satiety mechanisms
- Co-morbidities
- Medications
- Decreased orexigenic and increased anorexigenic signals
- Delayed gastric emptying
- Decreased small intestine motility
- Sensory impairments
- Medical/psychiatric disorders
- Social isolation, abuse, neglect
What does treatment involve for anorexia of aging?
support strategies
Define adipocytes
fat storing cells that store excess energy (triglycerides)
Define adipokines
include all of the biologically active substances synthesized by WAT which function in a lot of regulation…
What is the gastrointestinal tract?
a hollow tube that extents from mouth to the anus (mount, esophagus, stomach, small intestine, large intestine, rectum, anus)
What are accessory organs of digestive system?
- liver
- gallbladder
- exocrine pancreas
What does the digestive system perform?
performs the mechanical and chemical breakdown of ingested food
What does the digestive system prepare?
prepares food for uptake by the body’s cells
What does the digestive system provide?
body water
What does the digestive system eliminate?
wastes
What is the digestive system controlled by?
controlled by hormones and the autonomic nervous system.
What is not controlled by hormones and the ANS?
chewing, swallowing, and defecation
What is the alimentary canal responsible for?
- ingestion of food
- Propulsion of food and wastes from the mouth to the anus
- Secretion of mucus, water, and enzymes
- Mechanical digestion of food particles
- Chemical digestion of food particles
Absorption of digested food
Elimination of waste by defecation
What is the alimentary canal responsible for?
- ingestion of food
- Propulsion of food and wastes from the mouth to the anus
- Secretion of mucus, water, and enzymes
- Mechanical digestion of food particles
- Chemical digestion of food particles
- Absorption of digested food
- Elimination of waste by defecation
What is the order of the histology of the GI tract?
- mucosa
- submucosa
- muscularis
- serosa or adventitia (esophagus only)
Where is the submucosal plexus located?
located in the muscular mucosae
Where is the myenteric plexus located?
located between the inner circular and outer longitudinal muscle layers in the muscularis
What is the subserosal plexus located underneath?
just beneath the serosa
What do enteric (intramural) plexus neurons regulate?
motility reflexes, blood flow, absorption, secretions, and immune response
What is the mouth a reservoir for?
for chewing and mixing of food and saliva
What kind of digestion occurs in the mouth?
- chewing
2. salivation
What kinds of nerves are in the mouth?
olfactory nerves
What are three salivary glands?
- submandibular
- sublingual
- parotid
What is saliva composed of?
- water with mucus
- sodium
- bicarbonate
- chloride
- potassium
- salivary a-amylase (carb digestion)
What is saliva controlled by?
- sympathetic fibers (increases)
2. parasympathetic fibers (decreases)
What does saliva contain?
immunoglobulin A
What is a hollow muscular tube that measures ~25 cm long and conducts substances from the oropharynx to the stomach?
esophagus
Upper esophageal sphincter prevents the entry of what into the esophagus during respiration?
air
What are the two phases of swallowing
- oropharyngeal (voluntary)
2. esophageal phase (involuntary)
What is the brain structure responsible for swallowing?
reticular formation of brainstem
When the superior constrictor muscle of the pharynx contracts what does it prevent the movement of?
food into the nasopharynx
What slides downward to prevent a bolus from entering larynx and trachea?
epiglottis
Movements of what 2 structures propel food into the esophagus in a series of coordinated events that takes 1 or 2 seconds?
tongue and pharyngeal constrictors
What 4 things is the stomach responsible for?
- storing food
- secreting digestive juices
- mixing food with the juices
- propelling partially digested food (chyme)
What are the muscle layers of the stomach?
- longitudinal (outer)
- circular (middle)
- oblique (inner)
What are the 2 sphincters of the stomach?
- lower esophageal sphincter
2. pyloric sphincter
What does the pyloric sphincter allow?
allows food to exit the stomach into the duodenum
What are the 3 functional portions of the stomach?
- fundus (upper)
- body (middle)
- Antrum (lower)
What can the stomach absorb?
alcohol, aspirin, other non steroidal anti-inflammatory agents
true or false: stomach is permeable to water
false; impermeable to water
What relaxes with swallowing?
fundus
Gantrin and cholecystokinin enhance what?
relaxation of the stomach
What do gastrin and motilin and low BS?
peristalsis contractions of the stomach
sympathetic activity, secretin, cholecystokinin inhibit what?
peristalsis contractions of the stomach
vacus nerve stimulates what?
gastric secretion and motility
gastric mixing is enhanced by what?
retropulsion
Gastric emptying is the moment of what into what?
gastric contents into the duodenum
When does increased gastric emptying occur?
with larger volumes of food
When does delayed gastric emptying occur?
with solids, fats, and non-isotonic solutions
Mucus acts as a what?
protective barrier
What kind of acid is secreted by the stomach?
hydrochloric acid
What enzyme is in the stomach?
pepsinogen
What hormone is in the stomach?
gastrin
What does intrinsic factor do for gastric secretion?
intestinal absorption of vitamin B12
What facilitates small intestinal absorption?
gastroferrin
What do parietal cells secrete?
hydrochloric acid, gastroferrin, and intrinsic factor
What do chief cells secrete?
pepsinogen converted to pepsin in the gastric environment
What do G cells secrete?
gastrin
What do enterochromaffin-like cells secrete?
histamine
What do D cells secrete?
somatostatin
What are the 4 gastric glands in order?
- mucous neck cell
- chief cell
- parietal cell
- endocrine cell
What are the 3 segments of the small intestine?
- duodenum
- jejunum
- ileum
What does the ileocecal valve control? prevent?
- controls… the flow of digested material from the ileum into the large intestine
- prevents… reflux into the small intestine
What is the peritoneum?
serous membrane surrounding the organs of the abdomen and lining of the abdominopelvic cavity
What is the peritoneal cavity?
space between the visceral and parietal peritoneum
What 2 muscle layers comprise the small intestine?
outer: longitudinal
inner: circular
What is the function of villi in the small intestine?
absorption
What is the function of microvilli in the small intestine?
greatly increases absorption surface area
What is the connective tissue layer of the mucosa?
lamina propria
What is contained in each villus where fat molecules are absorbed and transported?
lacteals
Carbs must be what in the intestine?
must be hydrolyzed to their simplest form
pancreatic enzymes accomplish what in the small intestine?
major protein hydrolysis
Fats undergo what in the small intestine?
emulsification
Water and electrolytes are transported in what 2 directions in the small intestine?
- toward the capillary blood
2. toward the intestinal lumen
What does movement of the small intestine facilitate?
- digestion
2. absorption
What 2 movements promote motility?
- segmentation
2. peristalsis
define segmentation
rhythmic contractions of the circular smooth muscles
What does segmentation divide and mix?
divide and mixes chyme; puts it in contact with absorbent mucosal surface
define peristalsis
short segments of longitudinal smooth muscle wave contraction
what does peristalsis propel?
chyme through the intestine
What is the function of the ileogastric reflex?
inhibits gastric motility when the ileum is distended
What is the function of the intestinointestinal reflex?
inhibits intestinal motility when one part of the intestine is over distended
What is the function of the gastroileal reflex?
Stimulates an increase in ileal motility and relaxation of the ileocecal sphincter to empty the ileum and prepares it to receive more chyme
What is the function of the large intestine?
- messages fecal mass
2. absorbs water and electrolytes
What is the cecum of large intestine?
pouch that receives chyme from the ileum
What is the appendix attached to?
the cecum
What is the order of the colon?
- ascending
- transvers
- descending
- sigmoid
What comes first the anus or rectum?
rectum then anus
Is the stomach environment sterile or non-sterile? why?
sterile because of secreted stomach acid
What 3 things keep bacterial numbers in the duodenum to a min?
- bile acid secretion
- motility
- antibody production
What is there a low concentration of in the jejunum?
aerobes
What are 95% of the fecal flora in the colon?
anaerobes
What is the largest solid organ in the body?
liver
how are the lobes of the liver attached to the anterior abdominal wall?
by the falciform ligament
What 2 lobes compose the right lobe of the liver?
- caudate
2. quadrate
define glisson capsule of the liver:
fibroelastic capsule covering the liver
What are the 2 functions of the liver?
- bile secretion
2. enterohepatic circulation
What happens in enterohepatic circulation
recycling of bile salts
What is the byproduct of the destruction of aged RBCs?
bilirubin
What does bilirubin give bile in terms of color?
a greenish black color
Unconjugated (free) bilirubin is what kind of soluble?
lipid soluble
Conjugated bilirubin is what kind of soluble?
water soluble
What is responsible for giving urine its yellow color, and feces its brown color?
urobilinogen
What are another 7 functions of the liver?
- vascular and hematologic functions
- metabolizes fats
- synthesizes phospholipids and cholesterol
- metabolizes proteins
- metabolizes carbs
- metabolic detoxification
- storage of minerals and vitamins
What is a sac-like organ that lies on the inferior surface of the liver?
gallbladder
what is the function of the gallbladder:
to store and concentrate bile between meals
What is responsible for the hormonal regulation of gallbladder contraction?
cholecystokinin
What is does the exocrine pancreas secrete? what do these do?
- secretes enzymes and alkaline fluids
2. assist in digestion
What is the function of trypsinogen, chymotrypsinogen, and procarboxypeptidase of the pancreas?
inactivates proteases
What is the function of trypsin inhibitor of the pancreas?
prevents the pancreas from eating itself
what is the function of pancreatic a-amylase of pancreas?
digests carbs
what is the function of pancreatic lipase of pancreas?
digests fat
what is the function of pancreatic protease of pancreas?
digests protein
What are 6 things that happen with aging and the digestive system?
- Tooth enamel and dentin wear down
- Teeth are lost
- Number of taste buds decline
- Sense of smell and taste diminishes
- Salivary secretion decreases
- Esophageal motility decreases
What is there reduced secretions of with aging?
hydrochloric acid (slows gastric digestion and emptying)
What decreases with the intestine with aging?
intestinal motility and absorption of carbs, proteins, fats, and minerals
What decreases in efficiency with aging and the digestive system?
drug and alcohol metabolism
What is decreased efficiency of drug and alcohol metabolism related to?
decreased liver perfusion and decreased liver enzymes