120 q Flashcards
What are the four main layers of the gastrointestinal (GI) tract?
Mucosa, submucosa, muscularis, serosa
What is peristalsis?
Involuntary contractions that move food through the digestive tract
What is the function of the lower esophageal sphincter (LES)?
Prevents acid reflux into the esophagus
Where does most nutrient absorption occur in the GI tract?
Small intestine
What are villi, and why are they important for digestion?
Small projections that increase surface area for absorption
What is the role of bile in digestion?
Emulsifies fats
Where is bile produced and where is it stored?
Produced in the liver, stored in the gallbladder
What is the primary function of the liver in metabolism?
Regulates blood sugar, processes nutrients, detoxifies substances, and produces bile
What are the functions of hepatocytes?
Metabolism, detoxification, bile production
What is the portal triad in the liver?
Bile duct, hepatic artery, portal vein
What are the exocrine and endocrine functions of the pancreas?
Exocrine: digestive enzymes; Endocrine: insulin and glucagon
What is the role of insulin in the body?
Lowers blood glucose
What hormone is released when blood glucose levels are low?
Glucagon
Which cells in the pancreas secrete insulin?
Beta cells
Which enzyme is responsible for breaking down carbohydrates?
Amylase
What is basal metabolic rate (BMR)?
The rate of energy expenditure at rest
What is gluconeogenesis?
Production of glucose from non-carbohydrate sources
Which macronutrient is the primary source of energy for the body?
Carbohydrates
What is the role of the liver in gluconeogenesis?
Converts non-carbohydrates into glucose
What is ketosis?
A metabolic state where fat is used for energy, producing ketones
Which part of the brain regulates body temperature?
Hypothalamus
How does the body respond to a drop in temperature?
Shivering, vasoconstriction, increased thyroid hormone production
How does the body cool down in response to high temperatures?
Sweating, vasodilation
What is the primary mechanism for heat loss during exercise?
Evaporation (sweating)
What are the symptoms of heat stroke?
High temperature, confusion, rapid heart rate, loss of consciousness
What is the functional unit of the kidney?
Nephron
What are the three main processes involved in urine formation?
Filtration, reabsorption, secretion
Where does filtration occur in the nephron?
Glomerulus within Bowman’s capsule
What is the primary function of the loop of Henle?
Create concentration gradient for water/salt reabsorption
Which hormone increases water reabsorption in the collecting ducts?
Antidiuretic hormone (ADH)
What role does aldosterone play in the kidney?
Increases sodium reabsorption
What triggers the release of renin?
Low blood pressure or low sodium levels
What is glomerular filtration rate (GFR)?
Amount of filtrate produced by the kidneys per minute
What is nephroptosis?
Dropping of the kidney out of its normal position
What is heat exhaustion?
Dehydration and excessive sweating
What is cirrhosis?
Scarring of liver tissue leading to impaired liver function
What is pancreatitis?
Inflammation of the pancreas
What is jaundice, and what causes it?
Yellowing of skin and eyes due to liver dysfunction and bilirubin buildup
What is the main role of the gallbladder?
Stores and concentrates bile
What is the function of bile salts?
Emulsify fats for digestion
What enzyme digests proteins in the stomach?
Pepsin
Where does chemical digestion of carbohydrates begin?
In the mouth with salivary amylase
What is the primary function of the stomach?
Storage, mixing, and digestion of food
Which hormone stimulates hydrochloric acid secretion in the stomach?
Gastrin
What cells secrete hydrochloric acid in the stomach?
Parietal cells
What is chyme?
Partially digested food mixed with stomach acids
Which organ produces bile?
Liver
What are the primary functions of the large intestine?
Water absorption and feces formation
Where are the majority of digestive enzymes produced?
Pancreas
What triggers the release of bile into the small intestine?
The presence of fats (via cholecystokinin)
What is the role of the hormone secretin?
Stimulates the pancreas to release bicarbonate to neutralize stomach acid
What are the main end products of protein digestion?
Amino acids
Which hormone causes the liver to release stored glucose?
Glucagon
What is the role of the hepatic portal vein?
Carries nutrient-rich blood from the GI tract to the liver
Where is most water absorbed in the digestive system?
Large intestine
What is the primary role of the kidneys?
Filter blood and remove waste products
What structure in the nephron is responsible for filtration?
Glomerulus
What is the role of antidiuretic hormone (ADH)?
Increases water reabsorption in the kidneys
What is aldosterone, and how does it function in the kidneys?
A hormone that increases sodium reabsorption, leading to water retention
Where is urine stored before excretion?
Urinary bladder
What are the components of the renal corpuscle?
Glomerulus and Bowman’s capsule
How does the loop of Henle contribute to the concentration of urine?
By creating a concentration gradient in the medulla
Which cells in the pancreas secrete glucagon?
Alpha cells
What is the role of bicarbonate in the digestive system?
Neutralizes acidic chyme in the small intestine
What are the three parts of the small intestine?
Duodenum, jejunum, ileum
What are micelles?
Aggregates of bile salts that help with fat absorption
What is the function of chief cells in the stomach?
Secrete pepsinogen
What is the role of the liver in detoxification?
Processes toxins and drugs, breaking them down for excretion
Which nutrient is primarily absorbed in the small intestine?
Carbohydrates, proteins, fats
What is the function of the hepatic portal circulation?
To transport nutrients from the GI tract to the liver for processing
How does the body regulate blood glucose levels after a meal?
By secreting insulin from the pancreas
What is the function of the renal pelvis?
Collects urine and channels it into the ureter
What is the role of the hypothalamus in hunger regulation?
It releases hormones like ghrelin to signal hunger
What is the difference between the afferent and efferent arterioles in the kidney?
Afferent arterioles bring blood to the glomerulus; efferent arterioles carry it away
What is the primary role of the endocrine pancreas?
To regulate blood sugar levels
What hormone is responsible for increasing blood glucose levels during fasting?
Glucagon
What is the function of the pyloric sphincter?
Controls the passage of chyme from the stomach to the small intestine
How does sympathetic stimulation affect the digestive system?
It inhibits digestion by slowing motility and secretions
What is the role of pancreatic lipase?
Digests fats into fatty acids and glycerol
Where does the majority of fat digestion occur?
In the small intestine
What are ketone bodies, and when are they produced?
By-products of fat metabolism, produced during fasting or low carbohydrate intake
What is glycogenolysis?
The breakdown of glycogen to release glucose
How does the body respond to low body temperature?
By vasoconstriction, shivering, and increasing metabolism
What is the role of the proximal convoluted tubule in the nephron?
Reabsorbs nutrients, water, and ions back into the bloodstream
What does the term “basal metabolic rate” (BMR) refer to?
The rate at which the body uses energy at rest
What is the function of the distal convoluted tubule in the nephron?
Secretes ions and wastes into the filtrate
What is the importance of albumin in the blood?
Maintains osmotic pressure and transports substances
How does the liver aid in fat digestion?
By producing bile, which emulsifies fats
What is the countercurrent mechanism in the kidneys?
A system in the nephron that concentrates urine by allowing the reabsorption of water and salt
What stimulates the secretion of cholecystokinin (CCK)?
The presence of fats in the small intestine
Where is the hormone gastrin produced?
In the stomach by G-cells
What are the primary functions of the liver?
Metabolism, detoxification, storage of nutrients, and bile production
What happens when blood osmolarity increases?
ADH is released, increasing water reabsorption to dilute blood plasma
What triggers the secretion of ADH?
Increased blood osmolarity or dehydration
How does the body respond to high blood glucose levels?
By secreting insulin, which helps cells absorb glucose
What is the role of bile in fat digestion?
Bile emulsifies fats, making them easier to digest by enzymes
How is body temperature regulated by the hypothalamus?
By triggering sweating, shivering, and vasodilation or vasoconstriction
What is the primary function of the gallbladder?
To store and concentrate bile
What is the renal threshold for glucose?
The blood glucose concentration at which glucose starts appearing in the urine
How does the body regulate sodium levels?
Through aldosterone, which increases sodium reabsorption in the kidneys
What is the function of the detrusor muscle?
Contracts to expel urine from the bladder
What are the main components of urine?
Water, urea, creatinine, ions, and waste products
What is the juxtaglomerular apparatus, and what does it do?
A structure that regulates blood pressure and filtration rate in the kidney
How is chyme neutralized as it enters the small intestine?
Pancreatic bicarbonate neutralizes stomach acid
What is the role of the liver in protein metabolism?
The liver deaminates amino acids and converts ammonia to urea for excretion
