Anatomy II Exam 3
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106 Terms
Where intrinsic factor is made
Parietal cells in the stomach; Needed for absorption of vitamin B12 (used in red blood cell formation, or erythropoiesis).
Which cells make intrinsic factor
Parietal cells
Why is intrinsic factor important for vitamin B12 absorption
Most water-soluble vitamins, such as most B vitamins and vitamin C, also are absorbed via simple diffusion. Vitamin B12, however, combines with intrinsic factor produced by the stomach, and the combination is absorbed in the ileum via an active transport mechanism.,
Vitamin B₁₂ is vulnerable in the GI tract: It would be degraded or not absorbed properly without a carrier.
Intrinsic factor binds to B₁₂ in the small intestine: After B₁₂ is released from food in the stomach (thanks to stomach acid and enzymes), it first binds to a protein called haptocorrin. Then in the small intestine, enzymes break that bond, and B₁₂ binds to intrinsic factor instead.
The B₁₂–intrinsic factor complex travels to the ileum, where special receptors recognize it and absorb the vitamin into the bloodstream.
What is the portal triad?
a bile duct, branch of the hepatic artery, and branch of the hepatic vein
Hepatic artery – carries oxygenated blood from the systemic circulation (from the heart).
Hepatic portal vein – carries nutrient-rich, deoxygenated blood from the gastrointestinal tract (especially from the stomach, intestines, spleen, and pancreas).
Bile duct – collects and transports bile produced by hepatocytes toward the gallbladder and duodenum.
These three structures are usually surrounded by connective tissue, forming the "triad." Blood from the hepatic artery and portal vein flows through liver sinusoids toward the central vein, while bile flows in the opposite direction—from hepatocytes toward the bile duct.
Why vitamin B12 is important (big picture effect)
System, vitamin B12 is like a behind-the-scenes coordinator—it helps with absorption, gut lining health, nerve-driven movement, and possibly gut flora balance. A deficiency here doesn’t just affect your energy—it can mess with your whole digestive rhythm.
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Why is intrinsic factor important?
. Without intrinsic factor, vitamin B₁₂ would not be absorbed efficiently, leading to deficiency and serious health problems like anemia and nerve damage.
What are the different parts of small intestine
Duodenum, Jejunum and Ileum
The order of the regions of the small intestine
Duodenum (first part)
Jejunum (second part)
Ileum (third part)
So, the flow is:
Duodenum → Jejunum → Ileum
What are the three structures that make it up the portal triad?
Hepatic artery – Carries oxygenated blood to the liver from the heart.
Hepatic portal vein – Carries nutrient-rich, deoxygenated blood from the gastrointestinal tract (stomach, intestines, spleen, pancreas) to the liver.
Bile duct – Carries bile produced by hepatocytes (liver cells) away from the liver to the gallbladder and duodenum.
What is bile
a digestive fluid produced by the liver and stored in the gallbladder. It plays a crucial role in the digestion and absorption of fats in the small intestine.
What is the function of bile
Emulsifies fats for easier digestion and absorption.
Neutralizes stomach acid to protect the small intestine.
Helps with the absorption of fat-soluble vitamins (A, D, E, and K).
Excretes waste products like bilirubin and excess cholesterol.
Where is bile produced
Liver by hepatocytes (liver cells)
Where is bile stored
Gallbladder
What is the pathway bile takes to get to the duodenum
Liver (produces bile)
Hepatic ducts (transport bile)
Gallbladder (stores bile)
Cystic duct (transports bile to the common bile duct)
Common bile duct (transports bile to the duodenum)
Duodenum (bile helps digest fats)
What it does once it gets there;bile
its primary role is to aid in digestion, especially the digestion and absorption of fats.
Emulsifies fats for easier digestion by enzymes.
Helps absorb fatty acids and glycerol into the bloodstream.
Neutralizes stomach acidity to create a favorable pH for digestion.
Assists in the absorption of fat-soluble vitamins (A, D, E, K).
Facilitates the excretion of waste products like bilirubin and excess cholesterol.
The three mucosal layer or lining of the small intestine modifications
Plicae Circulares (Circular Folds): Large folds that increase surface area and slow down chyme movement.
Villi: Finger-like projections on the mucosal layer that further increase surface area and contain blood vessels and lacteals for nutrient transport.
Microvilli: Tiny projections on the epithelial cells of villi that form the brush border and enhance absorption, also housing digestive enzymes.
Why are they modified; mucosal layer or lining of the small intestine
allow for a large surface area, slow down digestion for optimal nutrient absorption, and enhance the breakdown and uptake of nutrients, making the digestive process much more efficient.
What they do know, what time is and where it's created.
1. What They Do:
This likely refers to the modifications of the mucosal layer of the small intestine (i.e., plicae circulares, villi, and microvilli). Here's a summary of what they do:
Plicae Circulares (Circular Folds):
Function: Increase surface area and slow down the movement of chyme, allowing for better digestion and absorption of nutrients.
Villi:
Function: Finger-like projections that further increase surface area and contain blood vessels and lymphatic vessels (lacteals) for nutrient transport.
Microvilli:
Function: Tiny projections on epithelial cells of the villi that form the brush border. They increase surface area for absorption and contain enzymes that help digest food particles.
2. What Time Is:
If you’re asking about time in the context of digestion, here's what might be relevant:
Time in digestion is important because the intestinal structures—including the modifications of the mucosal layer—help maximize the time available for nutrient absorption. By increasing the surface area (via plicae circulares, villi, and microvilli), food is given more time to interact with digestive enzymes and be absorbed.
3. Where It’s Created:
This might refer to the production of bile (based on your previous questions about bile).
Where Bile Is Created: Bile is produced in the liver by hepatocytes (liver cells
Digestive Hormones (3 Main Ones)
Cholecystokinin (CCK)
Secretin
Gastrin
What triggers their release, where they’re produced, and what they do:
Cholecystokinin (CCK)
Trigger for Release: Presence of fats and proteins in the duodenum.
Produced In: I cells in the mucosa of the duodenum and jejunum.
Functions:
Stimulates the gallbladder to release bile.
Stimulates the pancreas to release digestive enzymes.
Slows gastric emptying.
Promotes satiety.
Inhibits excessive gastric acid secretion.
What triggers their release, where they’re produced, and what they do:
Secretin
Trigger for Release: Presence of acidic chyme (low pH) in the duodenum.
Produced In: S cells in the mucosa of the duodenum.
Functions:
Stimulates the pancreas to release bicarbonate-rich fluid to neutralize stomach acid.
Inhibits gastric acid secretion to prevent excessive acidity in the small intestine.
Stimulates bile production in the liver.
Promotes the secretion of water and electrolytes to help create an optimal digestive environment.
What triggers their release, where they’re produced, and what they do:
Gastrin
Trigger for Release: Presence of food (especially proteins) in the stomach, stomach wall stretch, and vagus nerve stimulation during eating.
Produced In: G cells in the pyloric region (antrum) of the stomach.
Functions:
Stimulates gastric acid secretion (HCl) by parietal cells.
Promotes gastric motility to help churn food into chyme.
Stimulates the secretion of pepsinogen, which is activated into pepsin for protein digestion.
Promotes the growth and maintenance of the gastric mucosa.
Regulates gastric emptying to ensure proper digestion.
Where is Pepsinogen made
Chief cells of the stomach lining
What converts it into Pepsin
the acidic environment (low pH) in the stomach, primarily from HCl, is what converts pepsinogen into pepsin
Functions of Pepsinogen
Breaks down proteins into peptides.
It functions most effectively in acidic conditions (low pH).
It aids in the initial stages of protein digestion before other enzymes in the small intestine complete the digestion process.
What cells make the hormones in these different organs; Pepsin
Pepsinogen (the precursor of pepsin) is made by chief cells in the stomach.
Pepsin is formed when pepsinogen is activated by hydrochloric acid produced by parietal cells.
The names of key enzymes and what they break down:
Lipase, proteases, amylase, etc.
Enzyme | Produced By | Breaks Down | Location of Action |
|---|---|---|---|
Amylase | Salivary glands, pancreas | Carbohydrates (starches) into sugars | Mouth, small intestine |
Pepsin | Chief cells (stomach) | Proteins into smaller peptides | Stomach |
Lipase | Pancreas, salivary glands | Fats (lipids) into fatty acids and glycerol | Small intestine |
Lactase | Enterocytes (small intestine) | Lactose into glucose and galactose | Small intestine |
Sucrase | Enterocytes (small intestine) | Sucrose into glucose and fructose | Small intestine |
Maltase | Enterocytes (small intestine) | Maltose into glucose | Small intestine |
Trypsin/Chymotrypsin | Pancreas (inactive forms) | Proteins into smaller peptides and amino acids | Small intestine |
Carboxypeptidase | Pancreas (inactive form) | Peptides into amino acids | Small intestine |
Dipeptidase | Enterocytes (small intestine) | Dipeptides into amino acids | Small intestine |
Nucleases | Pancreas | Nucleic acids (DNA/RNA) into nucleotides | Small intestine |
What are brush border enzymes are and what do they do
splits off part of the trypsinogen molecule to form trypsin
The name of that duct that the pancreas and the and the bile get delivered through.
Common bile duct
The duct that both pancreatic secretions and bile use to reach the duodenum
The pancreatic duct and common bile duct merge at the hepatopancreatic ampulla and empty their contents into the duodenum via the major duodenal papilla.
Know the names and order of:
Right hepatic duct
Left hepatic duct
Common hepatic duct
Cystic duct
Bile duct
Right Hepatic Duct (collects bile from the right liver lobe)
Left Hepatic Duct (collects bile from the left liver lobe)
Common Hepatic Duct (formed by the union of the right and left hepatic ducts)
Cystic Duct (carries bile between the gallbladder and the common hepatic duct)
Common Bile Duct (formed by the union of the common hepatic duct and cystic duct, delivers bile to the duodenum)
Difference between motility and propulsion, segmentation
Term | What It Does | Where It Happens | Key Action |
|---|---|---|---|
Motility | All movement in the GI tract | Entire digestive system | Includes propulsion & segmentation |
Propulsion | Pushes food forward | Esophagus → Rectum | One-way movement |
Segmentation | Mixes food for digestion | Mostly small intestine | Back-and-forth mixing |
How smooth muscle contributes to motility and propulsion, segmentation
Function | Type of Smooth Muscle Involved | Movement Type | Purpose |
|---|---|---|---|
Propulsion | Circular + Longitudinal | Wave-like (peristalsis) | Push food forward |
Segmentation | Circular only | Back-and-forth | Mix food, enhance digestion |
So, smooth muscle = the engine behind digestion’s movement—propelling food forward and mixing it to break it down and absorb nutrients efficiently.
The role of gut flora (good bacteria) and what they contribute to digestion/health
🦠 Gut Flora (Good Bacteria) – Summary Gut flora are beneficial bacteria mostly found in the large intestine. They play a major role in:
Keeping gut flora balanced supports digestion, immunity, and mental health. Eating fiber, probiotics, and prebiotics helps them thrive, while overusing antibiotics can harm them. |
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What are paneth cells
specialized cells found in the small intestine, particularly located at the base of the crypts of Lieberkühn (the small pockets or glands in the intestinal lining).
Where are pannethh cells found
are found at the base of the crypts of Lieberkühn in the small intestine, specifically in the jejunum and ileum (the middle and end parts of the small intestine
What do panethh cells do
immune guardians of the small intestine
🔹 Found at the base of intestinal crypts
🔹 Kill harmful microbes
🔹 Support stem cells
🔹 Maintain gut balance
Modifications to the large intestine (know all 3)
Modification | Description | Function |
|---|---|---|
Teniae coli | 3 bands of smooth muscle | Aid movement & compaction |
Haustra | Pouches formed by teniae coli | Segment feces & absorb water |
Epiploic appendages | Fat-filled sacs on colon | Possibly fat storage & protection |
The purpose of modifications to the large intestine
Slow the movement of material,
Maximize water and salt absorption,
Compact waste into feces,
And facilitate safe passage and elimination.
what is brush border
the microvilli-covered surface of the epithelial cells that line the small intestine, especially in the jejunum and ileum.
What are brush border enzymes
are digestive enzymes located on the surface of microvilli in the small intestine (the brush border). They’re attached to the membrane of intestinal cells and help complete the final steps of digestion right before absorption.
What is the process of digestion
breaking down complex molecules into smaller absorbable ones
The difference between mechanical digestion (physical) and chemical digestion (enzymatic)
Type | Description | Examples | Purpose |
|---|---|---|---|
Mechanical | Physical breakdown of food | Chewing, churning, segmentation | Increase surface area for enzymes |
Chemical (Enzymatic) | Chemical breakdown using enzymes | Amylase, pepsin, lipase, etc. | Convert food into absorbable units |
What does acidic kind do
hypertonic and acidic
what does acicic kind do when it goes into the duodenal.
Neutralizes the acid with bicarbonate from the pancreas,
Releases hormones to coordinate digestion,
Continues breaking down nutrients with enzymes.
How do different types of food (e.g., fats vs carbs) affect transit time through the digestive system; how long it takes to get through your system
Carbs (simple): Fastest digestion (~1–3 hours).
Carbs (complex): Moderate digestion (~3–5 hours).
Proteins: Moderate digestion (~4–6 hours).
Fats: Slowest digestion (~6–8 hours).
Fiber-rich foods: Vary, but can either slow down or speed up transit time depending on fiber type.
The difference between the mesentery and the mesocolon.
The mesocolon is in the large intestine(supports large intestine), the mesentery small intestine(supports small intestine).
What is the peritoneum and its role
the largest serous membrane of the body; it lines the wall of the abdominal cavity and covers some abdominal organs.
The names of the sphincters and explain their roles
Cardiac (lower esophageal) sphincter
Pyloric sphincter
Ileocecal valve
Internal anal sphincter (involuntary)
External anal sphincter (voluntary)
What is chyme
Partially digested, semi-liquid substance that forms in the stomach after food has been mixed with gastric juices
Why chyme is considered hypertonic and acidic
Hypertonic: Chyme is hypertonic because it contains a high concentration of dissolved solutes, including gastric acid, digestive enzymes, and digested food components (proteins, amino acids, and fatty acids).
Acidic: Chyme is acidic because it is a mixture of partially digested food and hydrochloric acid secreted in the stomach, which gives it a low pH that aids digestion and defense against pathogens.
What happens when chyme enters the duodenum
When chyme enters the duodenum, several important processes occur:
The acidity of the chyme is neutralized by bicarbonate from the pancreas and bile from the liver.
Pancreatic enzymes and bile further break down the food components (proteins, fats, and carbohydrates).
Hormones like cholecystokinin (CCK) and secretin regulate the digestive process.
Some nutrients, such as iron and calcium, begin to be absorbed, although the majority of nutrient absorption occurs further down in the small intestine.
What are goblet cells
Goblet cells are specialized cells that secrete mucus in the epithelial lining of various organs. Their primary role is to protect, lubricate, and help in immune defense by trapping harmful substances and microbes.
What is the greater momentum and where does it attach
The greater omentum is a fatty, apron-like structure in the abdominal cavity that attaches to the greater curvature of the stomach and the transverse colon. It plays important roles in fat storage, immune defense, and protection of abdominal organs.
What is the the lesser momentum and where does it attach
The lesser omentum is a thin, two-layered fold of peritoneum that attaches to the lesser curvature of the stomach, the first part of the duodenum, and the liver. It plays roles in structural support, acting as a conduit for blood vessels and lymphatics, and maintaining connections between the stomach, duodenum, and liver.
What are the function of goblet cells in the digestive system
Secrete mucus that serves multiple functions:
Protects the epithelial lining of the GI tract from mechanical, chemical, and pathogenic damage.
Lubricates the passage of food through the digestive organs.
Offers immune defense by trapping and neutralizing harmful microorganisms.
Helps buffer stomach acid and prevent damage to the stomach lining.
Compare goblet cells role in the digestive vs. respiratory system
System | Goblet Cell Role | Mucus Characteristics |
|---|---|---|
Digestive System | Lubricates and protects GI tract, facilitates digestion | Thicker and more viscous for protection and lubrication |
Respiratory System | Traps and expels foreign particles, protects airways | Thinner, more fluid for easy movement and clearance |
🧩 Summary:
Digestive System: Goblet cells secrete thicker mucus to protect and lubricate the digestive tract and facilitate smooth food movement.
Respiratory System: Goblet cells produce thinner mucus to trap foreign particles, moisten the airways, and work with cilia to clear debris out of the respiratory tract.
Both systems rely on goblet cells for protection and function, but the mucus they produce and the role it plays differ due to the unique needs of each system.
Let me know if you'd like to explore more about how mucus impacts health or specific diseases in these systems!
Which cells produce hormones in the digestive system and which organ they are found in
Cell Type | Hormone Produced | Location | Function |
|---|---|---|---|
G Cells | Gastrin | Stomach (pyloric glands) | Stimulates gastric acid secretion |
S Cells | Secretin | Duodenum | Stimulates bicarbonate release from pancreas |
I Cells | Cholecystokinin (CCK) | Duodenum/Jejunum | Stimulates bile release from gallbladder |
K Cells | Gastric Inhibitory Peptide (GIP) | Duodenum/Jejunum | Inhibits gastric acid, stimulates insulin |
L Cells | Glucagon-Like Peptide (GLP-1) | Ileum/Colon | Stimulates insulin, slows gastric emptying |
ECL Cells | Histamine | Stomach | Stimulates gastric acid secretion |
D Cells | Somatostatin | Stomach, Duodenum, Pancreas | Inhibits other hormones like gastrin |
A Cells | Glucagon | Pancreas | Increases blood glucose |
B Cells | Insulin | Pancreas | Lowers blood glucose |
What is created in the small intestine (e.g., enzymes, hormones)
Substance | Type | Function |
|---|---|---|
Brush Border Enzymes | Enzymes | Break down carbohydrates, proteins, and nucleotides to their smallest components for absorption. |
Secretin | Hormone | Stimulates bicarbonate secretion from the pancreas to neutralize stomach acid. |
Cholecystokinin (CCK) | Hormone | Stimulates bile release and pancreatic enzyme secretion; inhibits gastric emptying. |
Gastric Inhibitory Peptide (GIP) | Hormone | Inhibits gastric acid and motility; stimulates insulin release. |
Glucagon-Like Peptide-1 (GLP-1) | Hormone | Enhances insulin secretion, slows gastric emptying, and reduces appetite. |
Motilin | Hormone | Stimulates motility in the small intestine. |
The three mucosal modifications and their role in increasing absorption
Circular folds slow down the chyme, mixing it and allowing better exposure to digestive enzymes.
Villi further increase surface area, ensuring more efficient nutrient absorption through their rich vascular and lymphatic networks.
Microvilli on the enterocytes provide the final step in nutrient digestion and increase the surface area to maximize nutrient uptake.
You may be asked to identify either a gastric pit or intestinal pit on a diagram.
Gastric Pit (Stomach):
Know the four cell types
Be able to identify a cell and describe its function (e.g. acid production, enzyme secretion, mucus, etc.)
Intestinal Pit (Includes villi and intestinal crypts):
Understand the structure and function of absorptive cells and other specialized cells in the crypts
identify the different parts of the nephron on that diagram.
The nephron consists of the Bowman’s capsule, glomerulus, proximal convoluted tubule, Loop of Henle, distal convoluted tubule, and collecting duct, each playing a crucial role in filtering blood, reabsorbing water and electrolytes, and excreting waste.
the two types of nephrons
Cortical nephron
Juxtamedullary nephron
Understand how the Cortical nephron and Juxtamedullary nephron differ structurally and functionally.
Feature | Cortical Nephron | Juxtamedullary Nephron |
|---|
Location of Renal Corpuscle | Primarily in the renal cortex | Near the border of cortex and medulla |
Length of Loop of Henle | Short, mostly in the cortex | Long, extending deep into the medulla |
Proximity to Medulla | Minimal extension into the medulla | Extends deep into the medulla |
Function in Urine Concentration | Less involved in concentrating urine | Major role in concentrating urine |
Filtration and Reabsorption | Regular filtration and reabsorption, less focus on urine concentration | Plays a significant role in concentration and water conservation |
Role in RAAS | Less influence on blood pressure regulation | More involvement in regulating blood pressure and filtration rate through the juxtaglomerular apparatus |
How to visually identify the differences between the Cortical nephron and Juxtamedullary nephron
Feature | Cortical Nephron | Juxtamedullary Nephron |
|---|---|---|
Location of Renal Corpuscle | Close to the renal cortex | Near the cortex-medulla junction |
Loop of Henle | Short, stays in cortex | Long, extends into medulla |
Proximity to Medulla | Shallow, mostly in the cortex | Deep, extends into the medulla |
Vasa Recta | Not prominent | Prominent, associated with long loops of Henle |
What is the JGA
specialized structure in the kidney that plays a crucial role in regulating blood pressure and kidney function. It is located where the distal convoluted tubule (DCT) of the nephron passes close to the afferent arteriole
What are the types of cells involved in the JGA
Juxtaglomerular (Granular) Cells: Produce and release renin, which helps regulate blood pressure through the renin-angiotensin-aldosterone system (RAAS).
Macula Densa Cells: Monitor sodium chloride levels in the filtrate and signal the juxtaglomerular cells to release renin when sodium levels are low.
Extraglomerular Mesangial Cells: Support communication between macula densa and juxtaglomerular cells and may help regulate glomerular blood flow.
Their location and function in the JGA
Juxtaglomerular (Granular) Cells:
Location: Afferent arteriole, near macula densa.
Function: Produce and secrete renin to regulate blood pressure and GFR.
Macula Densa Cells:
Location: Distal convoluted tubule (DCT), near afferent arteriole.
Function: Sense sodium chloride levels in filtrate and signal juxtaglomerular cells to release renin when levels are low, thus regulating GFR and blood pressure.
Extraglomerular Mesangial Cells:
Location: Between macula densa and juxtaglomerular cells.
Function: Facilitate communication between macula densa and juxtaglomerular cells, provide structural support, and may influence blood flow to the glomerulus.
Which nephron components are located in the cortex of the kidney.
Renal corpuscles (glomerulus and Bowman's capsule)
Proximal convoluted tubules (PCT)
Distal convoluted tubules (DCT)
Cortical nephrons (with most of their structures in the cortex)
Part of the juxtaglomerular apparatus (JGA)
Which structures extend into or are located in the medulla.
Loop of Henle (descending and ascending limbs)
Juxtamedullary nephrons (with their long loops of Henle)
Collecting ducts (which extend into the medulla and concentrate urine)
Vasa recta (capillaries that surround the loops of Henle in juxtamedullary nephrons)
Differnces between the cortical structures medullary structures
Feature | Cortex | Medulla |
|---|---|---|
Location | Outer region of the kidney | Inner region, beneath the cortex |
Key Structures | Renal corpuscles, PCT, DCT, peritubular capillaries | Loop of Henle, vasa recta, collecting ducts, renal pyramids |
Function | Filtration, reabsorption of nutrients and water | Urine concentration and water conservation |
Blood Supply | Afferent arterioles to glomerulus, peritubular capillaries | Vasa recta (supports concentration gradient) |
Appearance | Granular, lighter color | Striated, darker color |
Urine Concentration | Limited role in urine concentration | Central role in urine concentration and concentration gradient |
What is the bowman's capsule
cup-shaped structure that is part of the renal corpuscle, which is the initial part of the nephron in the kidney. It plays a crucial role in the process of filtration of blood to form the filtrate, which eventually becomes urine. Here's a detailed breakdown of its structure and function:
Recognize the afferent arteriole and efferent arteriole, and what are their roles.
Feature | Afferent Arteriole | Efferent Arteriole |
|---|---|---|
Direction of Blood Flow | Carries blood into the glomerulus | Carries blood out of the glomerulus |
Diameter | Wider in diameter, allowing for higher blood flow | Narrower in diameter, creating resistance to blood flow |
Pressure Function | Increases pressure in the glomerulus to promote filtration | Helps maintain pressure in the glomerulus for filtration |
Role in GFR Regulation | Constriction/dilation regulates blood flow into the glomerulus and GFR | Constriction/dilation helps control GFR by regulating glomerular pressure |
Blood Contents | Brings unfiltered blood to the glomerulus | Takes filtered blood away from the glomerulus |
But again, you'll have the picture. You also have a picture of the renal corpuscle. So you should know the cells, the parietal, and the visceral cells of the renal corpuscle, and then you'll have to know some of the histology of some of the cells throughout the tubules.
Parietal layer of the renal corpuscle: Simple squamous epithelial cells forming the outer layer.
Visceral layer of the renal corpuscle: Podocytes, specialized cells with foot processes that form filtration slits.
Endothelial cells of the glomerulus: Fenestrated cells that allow for the passage of small solutes and water.
Mesangial cells: Found within the glomerulus, regulate blood flow and filtration.
Proximal Convoluted Tubule: Cuboidal epithelial cells with microvilli (brush border).
Distal Convoluted Tubule: Cuboidal epithelial cells with fewer microvilli.
Loop of Henle: Simple squamous (descending limb) and cuboidal to columnar (ascending limb) epithelium.
Collecting Duct: Cuboidal cells and intercalated cells for acid-base balance.
Some questions will focus on histological characteristics of different nephron tubule cells (e.g., in the proximal convoluted tubule, etc.).
Be able to recognize and describe those differences.
Nephron Part | Histological Features |
|---|---|
Proximal Convoluted Tubule (PCT) | Cuboidal cells, brush border (microvilli), abundant mitochondria for active transport. |
Distal Convoluted Tubule (DCT) | Smaller cuboidal cells, no brush border, fewer mitochondria, larger lumen. |
Loop of Henle (Descending Limb) | Thin squamous cells, permeable to water, minimal cytoplasm. |
Loop of Henle (Ascending Limb) | Cuboidal to columnar cells, impermeable to water, active ion transport. |
Collecting Duct | Cuboidal cells, principal cells (clear cytoplasm), intercalated cells (dense cytoplasm), larger lumen. |
Summary:
When identifying and describing histological differences of nephron tubule cells:
PCT: Look for cuboidal cells with microvilli (brush border) and abundant mitochondria.
DCT: Look for smaller cuboidal cells without a brush border, less mitochondria, and a larger lumen.
Loop of Henle: The descending limb will be thin and squamous, while the ascending limb will have cuboidal/columnar cells.
Collecting Duct: Look for larger cuboidal cells, with intercalated cells for acid-base balance and principal cells for water and sodium reabsorption.
what renal corpuscle is
is the filtration unit of the nephron, consisting of the glomerulus (a capillary network) and the Bowman’s capsule (which surrounds the glomerulus and collects the filtrate). It plays a crucial role in initial filtration of the blood to produce filtrate, which will be further processed as it moves through the rest of the nephron.
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Identify structures in the renal corpuscle
Glomerulus: Network of capillaries responsible for blood filtration.
Bowman’s Capsule: Surrounds the glomerulus and collects the filtrate.
Parietal layer: Simple squamous epithelium (outer layer).
Visceral layer: Podocytes with foot processes forming filtration slits (inner layer).
Filtration Slits: Small gaps between podocytes that control what passes into the filtrate.
Afferent Arteriole: Brings blood to the glomerulus.
Efferent Arteriole: Carries blood away from the glomerulus.
Mesangial Cells: Located in the glomerulus, help regulate blood flow and maintain structure.
What kind of epithelium is found or the histology is found in the urinary bladder
Stratified epithelium with several layers of cells.
transitional epithelium
Hormones- renin
Renin is a hormone released by the kidneys that starts the renin-angiotensin-aldosterone system (RAAS), which helps regulate blood pressure, sodium balance, and fluid volume.
It converts angiotensinogen to angiotensin I, which is converted to angiotensin II, leading to:
Vasoconstriction (increases blood pressure).
Aldosterone release (promotes sodium and water retention).
ADH release (increases water retention).
Increased thirst (encourages fluid intake).
What produces renin
juxtaglomerular cells (also known as granular cells) of the juxtaglomerular apparatus (JGA), which is located in the kidney.
What is the urinary function
critical role in maintaining the body's homeostasis by regulating various physiological processes. Its primary function is to filter and remove waste products, excess substances, and toxins from the blood, while maintaining the balance of essential ions, water, and pH. The overall goal is to ensure that the body maintains a stable internal environment, known as homeostasis.
What is the function of the urinary system are
Filtration of blood to remove waste products.
Regulation of fluid, electrolyte, and acid-base balance.
Excretion of toxins and metabolic waste.
Regulation of blood pressure through the renin-angiotensin-aldosterone system.
Production of hormones like erythropoietin and calcitriol. These processes are critical for maintaining the body's internal environment and ensuring overall health.
The glomerulus explain
a crucial structure in the kidney that plays a central role in the filtration of blood to form urine. It is part of the renal corpuscle, which is the initial part of the nephron (the functional unit of the kidney).
Filtration: The glomerulus filters blood, allowing small molecules and waste products to pass into the Bowman’s capsule, while blocking large molecules like proteins and blood cells.
Filtration barrier: Made up of the fenestrated endothelium, basement membrane, and podocytes, the glomerulus selectively filters substances from the blood.
Regulation: The glomerulus is involved in maintaining a stable glomerular filtration rate (GFR), which is crucial for effective kidney function and waste elimination.
What are the differences in the capillary band that made it unique; what are those unique things
Fenestrated endothelium with pores to allow filtration of small molecules.
Thick basement membrane for additional filtration and to block large proteins.
Podocytes with foot processes that form filtration slits, adding another level of filtration.
High permeability and high pressure in the glomerular capillaries to ensure a large volume of filtrate is produced.
Close relationship with the juxtaglomerular apparatus for regulation of filtration pressure and rate.
Where in the nephron tubular reabsorption and tubular secretion takes place
Proximal Convoluted Tubule (PCT):
Reabsorption: Water, sodium, glucose, amino acids, bicarbonate, and other essential molecules.
Secretion: Hydrogen ions, ammonium ions, drugs, and metabolic waste products.
Loop of Henle:
Reabsorption: Water (descending limb), sodium and chloride (ascending limb).
Distal Convoluted Tubule (DCT):
Reabsorption: Sodium and calcium.
Secretion: Potassium and hydrogen ions.
Collecting Duct:
Reabsorption: Water and sodium (under hormonal control, mainly ADH and aldosterone).
Secretion: Potassium and hydrogen ions.
In summary, tubular reabsorption helps the body retain essential substances (such as water, sodium, glucose, etc.), while tubular secretion helps eliminate waste products and regulate important physiological balances (like pH and electrolytes).
The functional and structural unit of the kidney is
Structure:
The nephron is composed of a renal corpuscle and a renal tubule.
Renal corpuscle: This includes the glomerulus (a network of capillaries) and the Bowman’s capsule, where blood is filtered.
Renal tubule: This consists of:
Proximal convoluted tubule (PCT): Involved in the reabsorption of water, ions, and nutrients.
Loop of Henle: A U-shaped structure that plays a key role in the concentration of urine.
Distal convoluted tubule (DCT): Involved in the fine-tuning of electrolyte and fluid balance.
Collecting duct: Receives filtrate from multiple nephrons and is involved in further water reabsorption and regulation of sodium, potassium, and hydrogen ions.
Function:
The nephron is responsible for the filtration of blood, reabsorption of essential substances, and the secretion of waste products to form urine.
The glomerulus filters the blood, and the resulting filtrate moves through the renal tubule, where substances are reabsorbed or secreted as needed to maintain the body’s homeostasis (fluid balance, electrolyte levels, and pH regulation).
What is the JGA responsible for
regulates blood pressure and glomerular filtration rate (GFR). It releases renin in response to low sodium or low blood pressure, which triggers the renin-angiotensin-aldosterone system (RAAS) to increase blood pressure and GFR.
Put in order:the order in which urine is formed and leaves the body
Glomerulus (filtration of blood)
Bowman’s capsule (collects filtrate)
Proximal convoluted tubule (PCT)
Loop of Henle
Distal convoluted tubule (DCT)
Collecting duct
Renal pelvis (where collecting ducts drain)
Ureter (transports urine)
Bladder (stores urine)
Urethra (excretes urine from the body)
What is the trigon
triangular area in the urinary bladder. It is defined by three points:
The two ureteral openings (where the ureters enter the bladder).
The urethral opening (where urine exits the bladder).
The trigone is smooth and more sensitive than the rest of the bladder, and it remains stationary while the bladder walls stretch during filling.
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Why is the trigon there
serves as an important anatomical feature in the bladder. Its main functions include:
Preventing backflow: The triangular shape helps ensure that urine flows in one direction—from the kidneys through the ureters to the bladder and then to the urethra—by aiding the closure of the ureteral openings when the bladder contracts.
Bladder stability: The trigone helps maintain the structure and position of the bladder, allowing it to expand and contract as needed without distorting the openings of the ureters.
What are the differences between the pituitary capillaries and the vasareca
Function: Pituitary capillaries are involved in hormone transport; vasarecta are involved in maintaining water and solute balance in the kidneys.
Location: Pituitary capillaries are in the pituitary gland; vasarecta are around the nephrons in the kidneys.
Glomerular filtration
is a passive process, it is controlled by pressures not by any atp
The pressure in the glomerulus
is different then systemic blood pressure
Where are the kidneys located
located in the posterior part of the abdomen, on either side of the spine.
How are the kidneys kept where they are
Renal Fascia: A connective tissue layer that anchors the kidneys to surrounding tissues and helps maintain their position.
Perirenal Fat (Adipose Capsule): A layer of fat that surrounds the kidneys, providing cushioning and protection, while also helping to stabilize their position.
Fibrous Capsule: A tough outer layer directly covering the kidneys, providing structural support and protection.
Ureters: The tubes that transport urine from the kidneys to the bladder also help hold the kidneys in position, though this is a secondary function.
What is the renin-angiotensin-aldosterone mechanism
renin-angiotensin-aldosterone mechanism is a hormone system that helps regulate blood pressure, blood volume, and fluid balance. Here's how it works:
Triggering Renin Release:
When blood pressure drops, sodium levels decrease, or the sympathetic nervous system is activated, the juxtaglomerular cells in the kidneys release renin.
Renin Converts Angiotensinogen to Angiotensin I:
Renin acts on angiotensinogen, a protein produced by the liver, converting it to angiotensin I.
Angiotensin I is Converted to Angiotensin II:
Angiotensin I is then converted to angiotensin II by the angiotensin-converting enzyme (ACE), primarily in the lungs.
Effects of Angiotensin II:
Vasoconstriction: Angiotensin II causes blood vessels to constrict, raising blood pressure.
Aldosterone Release: It stimulates the adrenal glands to release aldosterone.
Aldosterone Increases Sodium and Water Retention:
Aldosterone acts on the distal convoluted tubule and collecting duct of the kidneys to promote sodium reabsorption.
Water follows sodium, increasing blood volume, which in turn helps raise blood pressure.
ADH (Antidiuretic Hormone):
Angiotensin II also stimulates the release of ADH from the pituitary gland, which increases water reabsorption in the kidneys, further helping to raise blood volume and pressure.
What the renin-angiotensin-aldosterone mechanism for
primarily helps to regulate blood pressure and fluid balance in the body. Its key functions include:
Increase Blood Pressure: It raises blood pressure when it drops (e.g., during dehydration or blood loss) by causing vasoconstriction (narrowing of blood vessels) and promoting sodium and water retention.
Maintain Fluid and Electrolyte Balance: By promoting the reabsorption of sodium and water in the kidneys, it helps to increase blood volume, which is crucial for maintaining proper hydration and electrolyte balance.
Regulate Kidney Function: It ensures that the kidneys maintain proper filtration rates and prevent excess loss of water and salt.
In short, the mechanism is vital for maintaining homeostasis, particularly under conditions of low blood pressure or volume.
What causes the kidney to reabsorb as a result of renin-angiotensin-aldosterone mechanism
Low Blood Pressure: When blood pressure drops, the kidneys detect this and release renin, which triggers the rest of the mechanism.
Low Sodium Levels: If sodium levels in the blood decrease, the kidneys release renin to restore sodium balance.
Sympathetic Nervous System Activation: Stress or a drop in blood volume can activate the sympathetic nervous system, signaling the kidneys to release renin.
The Steps:
Renin is released by the kidneys and converts angiotensinogen into angiotensin I.
Angiotensin I is converted to angiotensin II by the enzyme ACE in the lungs.
Angiotensin II causes vasoconstriction, raising blood pressure and stimulating the release of aldosterone from the adrenal glands.
Aldosterone acts on the kidneys, particularly in the distal convoluted tubule and collecting duct, to increase sodium reabsorption. Water follows sodium (via osmosis), which increases blood volume and blood pressure.
The system kicks in during periods of hypotension; what needs to happen in the kidney to raise blood pressure
the kidneys release renin, which triggers the renin-angiotensin-aldosterone system (RAAS):
Renin converts angiotensinogen to angiotensin I, which is then converted to angiotensin II by ACE.
Angiotensin II causes vasoconstriction (raises blood pressure) and stimulates aldosterone release.
Aldosterone increases sodium reabsorption in the kidneys, causing water retention and raising blood volume and pressure.
Put in order: the order that filtrate flows through the nephron
Glomerulus (filtration of blood)
Bowman’s capsule (collects filtrate)
Proximal convoluted tubule (PCT)
Loop of Henle
Distal convoluted tubule (DCT)
Collecting duct
Renal pelvis
Ureter
Bladder
Urethra
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