Mod 11: Block theory

What is the main function of the accessory digestive organs? (3)

• Aquire nutrients from food

• Provide enzymes for breakdown of food

• produce bile for digestion of dietary fat

What are 3 accessory digestive organs

• Liver

• Gallbladder

• Pancreas

Liver functions (3)

• produces bile for digestion of fats

• stores dietary glucose as glycogen

  • so it can later be broken down + used for energy

• role in metabolism of toxins, durgs, and alcohol in blood

What is the gallblader

a small organ underneath the liver

Gallbladder function

storage + release of bile in the digestive system

What is the pancreas? what does that mean?

A mixed gland

• has both endocrine + exocrine functions

Pancreas functions

• Endocrine: controls levels of blood glucose

• Exocrine: secrete digestive enzymes into intestine

Where is the liver found?

• sit in the upper right abdominal quadrant

• inferior to diaphragm

• anterior to vena cava

Liver has what four lobes

• right

• left

• caudate

• quadrate

What is the purpose of ligaments of the liver

attaches the liver to surrounding abdominal peritoneum and the diaphragm

what seperates the left and right lobes of the liver

Falciform

purpose of coronary ligament

suspends the liver from the inferior surface of the diaphragm

What is the porta hepatis/hilum of liver

• where hepatic vessels and ducts enter and leave the liver

Where is the portal hepatic located

• inferior side of liver

• surrounded by four lobes

what 3 structures enter and leave the portal hepatis

• Common hepatic duct

• portal vein

• hepatic artery

Function of common hepatic duct

• drains bile produced in the liver

• joins w/ cystic duct of the gallbladder to form the common bile duct

Describe portal vein function

• carries nutrient rich blood from digestive system → liver

• toxins/drugs travel through this vessel into the liver to be metabolized

Describe function of hepatic artery

• carries oxygenated blood to the liver

• branches to supply each lobe

What is the functional unit of the liver?

Liver lobule (hexagonal structure)

What cells make up the liver lobule

Simple cuboidal cells called hepatocytes

How are hepatocytes arranged

In plates (cords) radiating from a central vein

What are sinusoid?

spaces between hepatocyte plates where venous blood flows

What structures make up the portal (hepatic) triad

branches of the:

• hepatic artery

• poral vein

• common hepatic duct

Where are portal triads lcoated in the liver lobule?

• each lobule is surrounded by 6 travels

• one at each corner of the hexagon

What happens in the sinusoid?

• nutrient rich blood from the portal veins travels into the sinusoids

• inside, the nutrients from the blood is taken up into hepatocyte

What is the path of blood flow after sinusoid?

Sinusoids → central vein → hepatic vein → inferior vena cava → heart

note: this is oxygen poor blood

What is the pathway of bile flow in the liver?

Hepatocytes → canaliculi → bile ductules (portal triad) → hepatic ducts → common hepatic duct

what is liver cirrhosis?

• a slow, progressive disease

• healthy liver tissue is replaced by scar tissue

• prevents liver from functioning normally

Symptoms/dysfunctions in a patient with cirrhosis

• jaundice of skin

• distended abdomen (bloated look)

Describe the gallbalder shape and location

• peer-shaped muscular sac

• lies inferior to the right lobe of the liver

Gallbladder function

store + concentrate bile not immediately required for digestion

Describe and identify the 3 regions of the gallbladder

Fundus:

• found anteriorly

Body:

• between fundus + neck

Neck:

• found posteriorly

• connected to cystic duct

What does the biliary system consist of?

interconnected ducts that connect the liver and gallbladder

what does the duct system do?

stores and drains bile into the duodenum

what are the ducts of the biliary system?

• Hepatic ducts

• cystic duct

• common bile duct

Describe the hepatic duct

• 2 parts:

  • left + right hepatic ducts each coming from left or right lobe respectively

• drain bile into the common hepatic duct

Describe Cystic duct

• attaches to the common depatic duct

• functions to transport bile to + from the gallbladder

Describe the common bile duct

the common bile duct meets with the cystic duct to drain bile into the common bile duct, which enter the duodenum

Describe the pancreas (2)

• lobular organ → lies deep to the stomach

• both exocrine + endocrine functions

Describe and identify the parts the the pancreas is divided into (3)

• head

  • sits in the concavity of the duodenum

• body

  • passes behind the stomach

• tail

  • abuts the medial side of the spleen

function of the main pancreatic duct

• Collects the exocrine products of the pancreas

• fuses w/ comon bile duct to empty into the duodenum at the hepatopancreatic ampulla of vater

Pancreas composition

• 99% exocrine

• 1% endocrine

  • islets of langerhans scattered within this portion

The exocrine functions of the pancreas

• secretion of pancreatic juices from the pancreatic acini into the duodenum

Describe pancreatic juices

• rich in digestive enzymes

• contain bicarbonate ions to neutralize acid from the stomach

fill using anatomical terms

Functions of the kidneys (3)

• filter blood to produce urine

• balance ion concentration + body fluid volume

• produce erythropoitin

  • homrone that stimulates red blood cell production

what system do the kidneys belond to?

Urinary system

• kidneys mark the beginning of the urinary system

Why is urine production important?

• removes waste and excess ions from the body

Where are the kidneys located?

• on either side of the spine (T12-L2)

• against the posterior abdominal wall

What is the shape and general size of the kidneys

• bean shaped

• fist sized

12cm length

6.6cm width

2.5cm thick

Which kidney is lower and why?

Right kidney sits lower

• due to large size of liver

What is the hilum of the kidney?

the medial concave surface where vessels, nerves, and ureter enter/exit

what structures pass through the hilum?

Enter:

• Renal artery + nerves → enter

Exit:

• renal vein + ureters -→ exit

what is the renal sinus

• An internal space continous with the hilum

• filled w/ fatty tissue

What is the renal capsule?

A fibrous layer covering the kidney

What type of tissue is renal capsule made of?

dense irregular CT

what are the functions of the renal capsule?

• protects from injury/pathogens

• maintains kidney shape

What is the adipose capsule?

layer of adiopose tissue external to the renal capsule

adipose capsule function

• cusion + protection

• completely surrounds kidney

what are the two supportive tissue layers of the kidney

• renal capsule

• adipose capsule

Describe + identify the two internal anatomy of the kidney

• cortex

  • outer layer of kidney

• medulla

  • deep to cortex

what is the function of the cortex and medulla

filter blood to make urine

what are renal columns?

extensions of the cortex that seperate renal pyramids

what is the renal papilla?

The apex (tip) of the renal pyramid

What makes up each renal lobe of the kidney? (3)

the kidney is divided into renal lobes.. each lobe has:

• renal pyramid

• overlying cortex

• surrounding renal column

what ist he pathway of urine

kidney → renal papilla → minor calyx → major calyx → large renal pelvis → ureters

kidneys recieve their blood supply from what?

• paired renal arteries

  • branches of the abdominal aorta

Kideys are drained by what?

Renal veins

which renal artery is longer and why?

Right renal artery

• bc descending aorta is on the left, so it must travel further to reach the right kidney

WHhich renal vein is longer and why?

Left renal vein

• bc Inferior vena cava is on the right, so the left vein has to travel further

Relative positions of renal veins + arteries

renal vein is ANTERIOR to renal arteries

what ist he functionality unit of the kidney? what is its function

Nephrons (millions per kidney)

• filters blood + produced urine

What are the two main parts of a nephron

• renal corpuscle

• renal tubule

What two structures make up the renal corpuscle?

• Glomerulus capsule

• glomerular (Bowmans) capsule

what does the glomerulus consist of?

• bundles of capillaries

  • enclosed within the glomerular space

What is the capsular (Bowman’s) space?

Space between the glomerular capillaries and the capsule walls

how is filrate formed in the kidney?

Blood enters the glomerular capillaries → components of blood are filtered into bowmans space → this filtered fluid is called filtrate

what feature of glomerular capillaries allows filtration?

Fenestrations (small holes) that let water, ion, and small molecules pass

What are podocytes?

specialized cells that wrap around glomerular capillaries, forming filtration slits

What do filtration slits do?

permit water and salts to pass while restricting proteins

What are the three sections of the renal tube?

Proximal convoluted tubule → loop of henle —> distal convoluted tubule

What is the main function of the renal tubule?

• reabsorption + secretion of ions, water, and other substances to modify filtrate

Where does filtrate go after the renal tubules?

1. Into collecting tubules →

2. collecting ducts in the renal medulla

What happens in the collecting ducts?

Final processing/modification of filtrate occurs

When does filtrate become urine?

Once it leaves the collecting duct at the renal papilla

What is the function of the juxtaglomerular apparatus (JGA)?

Regulates blood pressure by monitoring ion concentrations in the filtrate

What are juxtaglomerular cells?

Modified smooth muscle cells of the afferent arteriole

What is the macula densa?

Modified cuboidal cells of the distal convoluted tubule

Function of the urinary tract

transfers + stores the urine produced by the kidneys until its ready for excretion

3 parts of the urinary tract

• ureters

• bladder

• urethra

Describe the ureters (4)

• 2 long, thin, muscular tubes

• connects kidney w/ bladder

• begin as a contuation of the renal pelvix

• extends toward pelvic cavity where they penetrate the posterior wall of the bladder

Describe the histological layers of the ureter

• adventitia

• muscularis

  • smooth muscle

• mucosa

  • transitional epithelium

What is the function of the urinary bladder?

Temporarily stores urine

What is the trigone of the bladder

A smooth triangular area at the base of the bladder

What structures define the trigone?

• Two ureter openings (superior)

• internal urethral opening (inferior)

what is the function of the trigone?

Funnels urine into the urethra + signals urge to void

Describe the neck of the urinary bladder

• constricted portion

• connected to the urethra inferiorly

• surrounded by an internal urethral sphincter

  • made up of smooth muscle

  • involuntary control

Describe the interior of the bladder

• Rugae → folded appearance

  • allows bladder to expand

Bladder location in females

• posterior to pubic symphysis

• inferior to uterus

• anterior to vagina

Bladder location in males

• posterior to pubic symphysis

• anterior to rectum