Histology of Specialized Tissues II GI & GU

GI Tract layers:

1. Mucosa

2. Submucosa

3. Muscularis

4. Adventitia/Serosa

Mucosa function:

Transport, absorption, digestion

Submucosa funtion:

Blood supply, lymphnoid

Muscularis function:

Smooth Muscle layer

Adventitia function:

Connective tissue with blood vessels/fat

Esophogus function:

Move food down into stomach

Does the esophogus have all 4 GI layers?

No

Stomach function:

digestion w/HCl, mucous, hormones

Which GI layers make up rugae in stomach?

Mucosa and submucosa

Small intestine function:

Nutrient absorption

What parts are in small intestine:

duodenum, jejunum, ileum

Large intestine function:

absorb water, high bacterial content

What cells are found in the large intestine:

Goblet cells

Rectum funtion:

chamber for stool

Hemorrhoids often result of:

Straining causing blood vessels to become engorged

Internal hemorrhoids are located:

above pectinate line

External hemorrhoids are located:

below pectinate line

Painful hemorrhoids caused by blood clots in vessel is called:

Thrombosed hemorrhoid

What two types of hormones does the pancrease secrete:

Exocrine (into duct) & Endocrine (into bloodstream)

Enteroendocrine cells produce two hormones that cause pancreatic fluid secretion:

Secretin & Cholecystokinin

Secretin:

Cause acinar and duct cells to add H2O & HCO3 to fluid

Cholecystokinin:

Fats, gastric acid, AA trigger release allowing for bile to be released

Islet of Langerhans is what type of hormone:

exocrine

Insuling and C-peptide are released from which cells:

Beta cells

Glucagon is released from what cells:

Alpha cells

Insulin:

Anabolic (build up), drive blood glucose out of blood stream

Glucagon:

Catabolic (breakdown), breakdown glycogen to raise blood glucose

Ways that insulin lower blood glucose:

1. Stimulate production of glycogen → glycogenesis

2. Stimulate glycolysis → cellular respiration

3. Stimulate triglycerides → formation of fatty acids/glycerol

4. Inhibit gluconeogenesis (make carbs from noncarbs)

What stimulates the release of glucagon:

Hypoglycemia

How does glucagon raise blood sugar:

1. Promote glycogenolysis

2. Promote gluconeogenesis

3. Promote proteolysis

4. Promote lipolysis

Function of liver:

neutralize toxins, absorb LDL, make proteins, produce bile, cholesterol, fatty acids, triglycerides

Parenchyma of liver:

Lobules

Glycogenesis:

Additional glucose stored as glycogen

Glycogenolysis:

Stored glycogen breaks down into glucose

Key enzyme for glycogenolysis:

Glycogen phosphorylase

Gluconeogenosis:

Production of glucose from non-carbohydrates (lactate, pyruvate, AA, glycerol)

Jaundice:

Accumulation of bilirubin in tissues/blood

Renal hilum:

VAN connect to kidney

Renal pelvis:

central collection of urine before ureter

Renal calices:

Minor and major collect filtrated blood substanes

Renal cortex:

Where most of the nephron hangs out

Renal medulla:

Loop of Henle (urine concentrated)

Parenchyma of the kidney:

Nephron

Kidney function:

1. Filtrate

2. Regulate BP

   1. Regulate blood pH

Glomerulus function:

Hold protein in blood

What does it mean when a UA test shows protein?

Damage to membrane

GFR stands for:

Glomerular Filtration Rate

When kidneys fail, blood volume being filtered decreases, what would the GFR be?

Below 90-120mL/min

Where in the nephron does Na+ and H2O get absorbed?

Proximal convoluted tubule

What is a serum creatinine measuring?

Breakdown of creatine phosphate from muscle that tunrs into creatinine

Parts of the Loop of Henle:

1. Descending loop

2. Ascending loop

Descending loop function:

H2O move out → leave concentrated urine

Ascending loop function:

NaCl reabsorbed → urine diluted

Distal convoluated tubule function:

1. Aldosterone help reabsorb Na+

2. HCO3 reabsorbed

3. PTH reabsorb Ca2+

Collecting duct:

1. Control aquaporin channels to allow H2O reabsorb into blood supply

2. Urea passively pump

How can kidney disease contribute to anemia?

Kidneys regulate BP and O2 levels, if O2 is low EPO can activate bone cells to turn into RBC

What type of tissue does the ureter and bladder have?

Transitional epithelium (allow for expansion)

How does the kidney contribute to BP regulation?

1. Renin released from kidney

2. Angiotensinogen released from liver

3. Renin and angiotensinogen create angiotensin I

4. ACE released from lungs

5. ACE and angiotensin I create angiotensin II

6. Angiotensin II stimulate vasocontriction