ANAT 100 - Module 11

Accessory Organs

Accessory Organs

Provide enzymes that breakdown food and bile to digest dietary fats

• liver, gallbladder, pancreas

1. Liver

2. Gallbladder

   1. Pancreas

Liver

• produces bile for digestion of fats

• Stores glycogen

  • Metabolizes toxins, drugs, alcohol in blood

Gallbladder

Storage and release of bile

Pancreas

• mixed gland → endocrine and exocrine functions

• Control blood glucose

• Secretes digestive enzymes into intestine

4 lobes of the liver

1. Right lobe

2. Left lobe

3. Quadrate lobe

4. Caudate lobe

1. Diaphragm

2. Liver

3. inferior vena cava

1. Right lobe

2. Left lobe

1. Quadrate lobe

2. Left lobe

3. Caudate lobe

4. Inferior vena cava

5. Right lobe

Ligaments of the liver

Attaches to liver to abdominal peritoneum and diaphragm

1. Coronary ligament

2. Falciform ligament

Abdominal peritoneum

Membrane between abdominal cavity and covers most of abdominal organs

1. Coronary ligament

2. Falciform ligament

Coronary ligament

Suspends liver from inferior surface of diaphragm

Falciform

Separates right and left lobe

Porta hepatis (hilum)

• area where hepatic vessels and ducts enter and leave liver

• Hepatic vessels: common hepatic duct, portal vein, hepatic artery

Porta hepatis

Common hepatic duct

Common hepatic duct

• drains bile produced in liver

• Combines with cystic duct of gallbladder to create common bile duct

Portal vein

Portal vein

• carries nutrient rich blood from digestive system into liver

• Toxins travel through vessel into liver for metabolism

Hepatic artery

Hepatic artery

Carries oxygenated blood to liver and branches to supply each lobe

Liver lobule

Simple cuboidal liver cells → hepatocyte cords that radiate outward from central veins

Sinusoids

Between cell plates where venous blood flows

1. Liver lobule

2. Central vein

3. Hepatocytes

4. Sinusoids

Portal triads

Branches of hepatic artery, portal vein, hepatic duct (bile ductule) from porta hepatis

• each liver lobe surrounded by 6 triads

1. Central vein

2. Bile ductule

3. Portal vein

4. Hepatic artery

5. Portal triad

1. Portal triad

2. Central vein

Flow of venous blood

Portal vein → sinusoids → central veins → hepatic veins → inferior vena cava → heart

1. Central vein

2. hepatocytes

3. Portal vein

Where are bile fats produced?

Hepatocytes to aid in digestion

Flow of bile fats

Hepatocytes → canaliculi (small channels) → bile ductules → hepatic ducts

1. Canaliculi

2. Bile ductule

What are the functions of the liver?

• produces bile → emulsification of fats and cholesterol

• Stores nutrients as glucose

Liver cirrhosis

Slow progressive disease where healthy tissue is replaced by scar tissue

• blocks flow of blood and bile through portal triads

Gallbladder

Gallbladder

Pear-shaped muscular sac inferior to right liver lobe

• stores and concentrates bile

Areas of Gallbladder

1. Fundus

2. Body

3. Neck

1. Fundus

2. Body

3. Neck

4. Cystic Duct

Billary system

Interconnected ducts that connect liver and gallbladder

• stores and drains bile into duodenum

Flow of bile

Cystic duct → common hepatic duct → common bile duct

Hepatic duct

Drain bile into common hepatic duct

Cystic duct

Attaches to common hepatic duct and transports bile to and from gallbladder

Common bile duct

Meets cystic duct to drain bile into commonbile duct which enters duodenum

1. Right hepatic duct

2. Left hepatic duct

3. Common hepatic duct

4. Cystic duct

5. Common bile duct

1. Pancreas

2. Duodenum

Pancreas

• lobular organ deep inside stomach

• Exocrine and endocrine functions

• Exocrine secretes enzymes that aid in digestion

1. Head

2. Body

3. Tail

Pancreas head

Concavity of duodenum on right side of abdominal cavity

Pancreas body

Extends towards left, passing behind stomach and tapering to become tail

Pancreas tail

Medial side of spleen

Main pancreatic duct

• Collects exocrine products of pancreas

• Duct fuses with common bile duct to empty into duodenum through ampulla of vater

1. Common bile duct

2. Main pancreatic duct

3. Ampulla of vater

Histology of pancreas

1. 99% exocrine

2. 1% endocrine (islets of langerhans)

1. Exocrine pancreas

2. Endocrine pancreas (islets of langerhans)

Role of exocrine pancreas

Secretes pancreatic juices from pancreas acini into duodenum

Components of exocrine pancreas

1. Pancreatic acini

2. Duct

Pancreatic juices

Rich in digestive enzymes

• contain bicarbonate ions to neutralize acid from stomach

Why are digestive juices important?

Used to obtain nutrients from ingested food

Kidneys

Filters blood to produce urine

Location of kidneys

bean shaped organs in abdominal region on both sides of T12-L2 vertebrae

Size of kidney

• 12cm length

• 6.5cm width

• 2.5 cm thickness

Why is the right kidney slightly lower in the abdominal cavity?

Liver is too large and sits superiorly and limits ascent of kidney

1. Renal sinuses

2. Hilum

Hilum of kidney

Medial surface

Renal sinus

Internal space in each kidney → fatty tissue

Supportive tissues of kidney

Protects and cushions kidneys

1. Renal capsule

2. Adipose capsule

Renal capsule

Covers outer surface of kidney

• dense irregular tissue

• Protection from pathogens

• Maintains shape

Adipose capsule

Adipose tissue external to renal capsule

• cushion and protection

Internal anatomy of kidney

Both filter blood to produce urine

1. Renal cortex

2. Renal medulla

1. Renal papilla

2. Renal lobe

3. Renal column

4. Renal pyramid

Renal lobe diagram

1. Renal Cortex

2. Renal column

3. Renal papilla

4. Renal pyramid

5. Renal column

Renal lobes

Each lobe has renal pyramid, cortex, and surrounding renal column

Renal columns

Extension of cortex → separates medullary into renal pyramids

Renal papilla

Apex of pyramid

Renal pelvis

Urine → minor calyces → major calyx → renal pelvis → uterus

1. Renal papilla

2. Minor calyces

3. Major calyx

4. Renal pelvis

5. Ureter

1. Abdominal aorta

2. Left renal artery

3. Right renal artery

Blood supply

Kidneys receive blood from paired renal artery

• renal artery = branches of abdominal aorta

1. Inferior vena cava

2. Left renal vein

3. Right renal vein

Blood drainage

Kidneys drain by renal veins into inferior vena cava

Difference between renal artery supplying right kidney compared to real artery supplying left kidney

• right artery longer than left

• Right vein shorter than left

Renal Corpuscle

1. Bowman’s capsule

2. Bowman’s space

3. Glomerulus

Glomerulus

Bundle of capillaries within glomerular capsule

Bowman’s space

Space between walls and glomerular capillaries

Fenustrations

Capillaries of glomerulus with holes

• allows ions, water, and molecules to move through membranes

Podocytes

Surrounds glomerular capillaries

• creates filtration slits that allow water and salts to pass

1. Distal convoluted tubule (DCT)

2. Proximal convoluted tubule (PCT)

3. Loop of henle

Renal Tubule

Extends throughout cortex and medulla of kidney

• 3 sections: proximal convoluted tubule, loop of henle, distal convoluted tubule

1. Renal cortex

2. Renal medulla

3. Renal corpuscle

4. Renal tubule

Collecting system

Renal tubules → collecting tubules → collecting ducts (inside renal medulla)

• final filter: collecting duct → renal papilla → urine

1. Collecting duct

2. Renal papilla

Juxtaglomerular apparatus

Strict unit that regulates blood pressure by monitoring ion concentration in filtrate

Juxtaglomerular cells

Modified smooth muscle cells of afferent arteriole

• smaller artery brings blood into glomerulus

Macula densa

Modified cuboidal cells of distal convoluted tubule

1. Juxtaglomerular cells

2. Macula densa

3. Distal convoluted tubule

Kidneys summary

• Kidneys: filter blood to get rid of waste, balance ion concentrations, produce RBC

• Produce urine through nephrons

• Pass filtrate on minor and major calyces into renal pelvis (drains ureters)

Urinary tract

Transfers and stores urine produced by kidneys until ready for excretion

3 parts of urinary tract

1. Ureters

2. Bladder

3. Urethra

1. Kidney

2. Ureter

3. Bladder

4. Urethra