Exam 3 Study Guide

Two ways blood is delivered to the liver

·       Portal vein (70%): nutrient-rich blood from GI tract

·       Hepatic artery (30%): oxygen-rich arterial blood

What changes occur in liver cells when the liver is damaged/harmed?

·       Necrosis or apoptosis of hepatocytes

·       Fat accumulation (steatosis)

·       Inflammation and fibrosis if injury is chronic

Myocardial damage (heart attack(

Dead myocardium → permanent scar (does NOT regenerate)

Acute Hep A damage (liver damage)

o   Hepatocytes regenerate fully once infection resolves

o  No chronic disease

What is liver cirrhosis

Diffuse scarring of liver, loss of normal structure, impaired circulation

What causes liver cirrhosis

 chronic injury: alcohol, hepatitis B/C, fatty liver disease

Why is chronic hepatitis infection a public health issue?

·       Causes liver failure, cirrhosis, liver cancer

·       Many people are asymptomatic carriers

·       Easily spread (HBV via blood/sex; HCV via blood)

·       Major contributor to global mortality

What viral hepatitis infections have vaccines

Hepatitis A and B

What viral hepatitis infections don’t have vaccines

Hepatitis C

Why are Hep B rates lower in the U.S. than in developing countries?

·       Universal infant vaccination

·       Screening of blood products

·       Lower rates of perinatal transmission

·       Better healthcare + infection control

Hepatitis C: % chronic carriers

75–85%

Hepatitis C: % cirrhosis

20–30% 

Hepatitis C: % liver cancer

1–4% per year 

Barriers to hepatitis C prevention & treatment

·       High medication cost

·       Many asymptomatic so remain undiagnosed

·       Stigma around drug use

·       Limited access to healthcare

·       Lack of screening among at-risk groups

Two key causes of fatty liver disease in the U.S.

·       Alcohol use (AFLD)

·       Obesity & metabolic syndrome (NAFLD)

Three leading causes of liver cirrhosis

·       Chronic hepatitis C

·       Chronic hepatitis B

·       Chronic alcohol use
(NAFLD is rising fast)

Clinically observable signs of cirrhosis

·       Ascites

·       Jaundice

·       Spider angiomas

·       Bruising

·       Muscle wasting

·       Peripheral edema

·       Hepatic encephalopathy

Why is rupture of esophageal varices an emergency?

·       Varices are thin-walled veins under high pressure

·       Rupture causes massive gastrointestinal bleeding, can be fatal

What can precipitate hepatic encephalopathy?

·       GI bleeding

·       High protein intake

·       Infection

·       Constipation

·       Dehydration

·       Medications (sedatives)

Why might TIPS increase risk of hepatic encephalopathy?

·       TIPS shunts blood around the liver, so toxins are not filtered

·       More ammonia reaches the brain

True or false: People who die with hepatitis C cannot donate their livers.

·       False.

o   Hep C–positive livers can be transplanted into Hep C–positive recipients (and now into negative recipients because HCV is curable).

What does bile do to fat?

Emulsifies fat, increasing surface area for digestion by lipases.

What is a cholecystectomy

Surgical removal of the gallbladder

When is a cholecystectomy done

Performed for symptomatic gallstones, infection, or gallbladder dysfunction

Public health interventions to reduce hepatocellular carcinoma in high-HBV countries

·       Universal HBV vaccination

·       Birth-dose HBV vaccine

·       Screening pregnant mothers

·       Treating chronic HBV

·       Safe injection practices

What is driving the rapid increase of liver cancer in the U.S.?

·       Rising rates of NAFLD/NASH

·       Chronic hepatitis C in aging population

·       Obesity + diabetes epidemic

What is secreted by alpha cells?

Glucagon

Glucagon effects on blood sugar

·       Raises blood glucose by:

o   Stimulating glycogen breakdown

o   Stimulating gluconeogenesis

What is secreted by beta cells?

Insulin

Insulin effects on blood sugar

·       Lowers blood glucose by:

o   Increasing glucose uptake by cells

o   Promoting glycogen & fat storage

Why are people with gallstones more likely to develop acute pancreatitis?

Gallstones can block the common bile duct, which joins the pancreatic duct → pancreatic enzymes back up → autodigestion of pancreas.

Connection between chronic pancreatitis and diabetes

Chronic inflammation destroys beta cells in pancreas → insulin deficiency → diabetes.

Where in the body does cystic fibrosis cause problems?

·       Lungs (airway obstruction, infections)

·       Pancreas (blocked ducts → malabsorption)

·       Liver/bile ducts

·       Reproductive system

·       GI tract

Why are people with uncontrolled diabetes frequently thirsty (polydipsia)?

·       High blood glucose → glucose spills into urine

·       Glucose causes osmotic diuresis → excessive water loss

·       Body responds with extreme thirst

What would you tell a patient with an A1c of 6.1?

·       Indicates prediabetes

·       Lifestyle changes (diet, exercise, weight loss) can reverse progression

·       Monitor glucose, repeat A1c in 3–6 months

What percentage of adults >65 have diabetes in the U.S.?

~25% (1 in 4)

What causes type 1 diabetes?

·       Autoimmune destruction of pancreatic beta cells

·       Results in absolute insulin deficiency

·       Often triggered by viral infections + genetic susceptibility

Cause of type 2 diabetes (more than obesity)

·       Insulin resistance in muscle, liver, and fat

·       Beta-cell exhaustion → decreasing insulin over time

·       Strongly associated with:

o   Visceral obesity

o   Chronic inflammation

o   Genetic predisposition

o   Sedentary lifestyle

How dyslipidemia in type 2 diabetes affects the body

·       High triglycerides and low HDL → atherosclerosis

·       Leads to increased risk of:

o   Heart attacks

o   Strokes

o   Peripheral vascular disease

Identical twins: risk of other twin developing diabetes type 1

~40% 

Identical twins: risk of other twin developing diabetes type 2

~75–90% 

What percentage of people with prediabetes develop type 2 diabetes?

·       5–10% per year

·       Up to 70% lifetime risk

Components of metabolic syndrome

Must have 3 of the following:

·       High waist circumference (central obesity)

·       High blood pressure

·       High fasting glucose

·       High triglycerides

·       Low HDL cholesterol

Two conditions that could cause hypoglycemia in insulin users

·       Skipping meals after taking insulin

·       Too much insulin (dose error or increased sensitivity)

·       Bonus: Increased exercise, alcohol

Treatment plan for children with cleft lip and/or palate

·       Surgical repair (lip at ~3 months, palate at ~9–18 months)

·       Feeding assistance (special bottles)

·       Speech therapy

·       Dental/orthodontic care

·       ENT follow-up

·       Goal: restore feeding, speech, and facial structure

Why is tetracycline avoided during pregnancy?

·       Causes permanent discoloration of fetal teeth

·       Can inhibit fetal bone growth

Components of dental plaque

o   Bacteria

o   Saliva proteins

o   Food particles

Why dental plaque is a problem

o   Tooth decay (acid from bacteria)

o   Gum disease (gingivitis → periodontitis)

What irritants can lead to stomatitis?

·       Alcohol

·       Tobacco

·       Hot foods

·       Spicy foods

·       Dentures/poor dental hygiene

·       Chemotherapy

·       Viral infections (HSV)

True or false: Squamous cell carcinoma of the oral cavity is common and rarely metastasizes.

·       False.

o   It is common but can metastasize early to cervical lymph nodes.

o   True statement: “It is common and often spreads to lymph nodes.”

Why is oropharyngeal cancer rising in younger people despite decreases in smoking?

·       Strong link to HPV infection (HPV-16)

·       Sexual transmission has increased HPV-related throat cancers.

achalasia

o   Lower esophageal sphincter fails to relax

o   Causes difficulty swallowing, food retention

incompetent cardiac sphincter

o   Sphincter does not close fully

o   Causes GERD, acid reflux

Common treatments for GERD

·       Lifestyle changes: avoid large meals, reduce caffeine/alcohol, weight loss

·       Medications: antacids, H2 blockers, PPIs

·       Surgery (fundoplication) for severe cases

Benefit of COX-2 inhibitors

Pain relief with less gastric irritation than NSAIDs

Risk of COX-2 inhibitors

Increased cardiovascular risk (heart attack, stroke)

How does H. pylori increase cancer risk?

·       Causes chronic inflammation → DNA damage

·       Leads to gastric ulcers and gastric carcinoma over time

Why is peptic ulcer treatment antacids + antibiotics?

·       Antacids/PPIs: reduce acid so ulcer can heal

·       Antibiotics: eradicate H. pylori, the underlying cause

Why is stomach cancer decreasing?

·       Lower H. pylori prevalence

·       Better food storage (less salted/smoked foods)

·       More fresh produce in diet

Common locations for viral gastroenteritis outbreaks

·       Daycares

·       Nursing homes

·       Cruise ships

·       Schools

·       Restaurants

·       Norovirus is highly contagious

Why is bacterial gastroenteritis dangerous for children in developing countries?

·       Causes severe dehydration

·       Limited access to clean water, oral rehydration, and medical care

·       Major cause of child mortality

Potential issues with offering only milk as beverage in schools

·       Lactose intolerance → GI upset

·       Excess calories → weight gain

·       Interferes with iron absorption → anemia risk

·       Limits hydration variety

Primary symptoms of celiac disease

diarrhea, bloating, weight loss, nutrient deficiencies

Root cause of celiac disease

Autoimmune reaction to gluten → villous atrophy in small intestine

True/False: IBS is diagnosed via endoscopic biopsy.

·       False.

o   IBS is a functional disorder diagnosed clinically by symptoms, not biopsy.

How is appendicitis treated?

·       Surgical removal (appendectomy)

·       Antibiotics pre- and sometimes post-op

Two diseases that comprise IBD

·       Crohn disease

·       Ulcerative colitis

Can Crohn disease affect the entire bowel wall thickness?

Yes — “transmural” inflammation

Does ulcerative colitis affect the entire thickness of the colon?

No — limited to mucosa & submucosa

How does antibiotic use lead to C. difficile infection?

Antibiotics kill normal gut flora → C. diff overgrows → toxin production → colitis

diverticulosis

outpouchings; usually asymptomatic

diverticulitis

inflamed/infected pouches → pain, fever, abscess

What diet predisposes to diverticula?

Low-fiber diets

Why is early detection of colon cancer important?

·       Early lesions are curable

·       Later-stage cancers metastasize and have poor prognosis

Two methods to screen for colon cancer

·       Colonoscopy

·       FIT test (fecal immunochemical test)

Diseases associated with obesity

·       Type 2 diabetes

·       Hypertension

·       Heart disease

·       Stroke

·       Fatty liver disease

·       Cancer

·       Sleep apnea

Why are infants and children disproportionately affected by malnutrition?

·       Higher nutrient needs per body weight

·       Limited fat stores

·       Rapid growth requires more protein

·       Infections worsen nutrient loss

Term for deficiency of calories in infants/children

Marasmus

Term for adequate calories but inadequate protein

Kwashiorkor

Osteoblast

build bone; become osteocytes

Osteoclast

break down (resorb) bone

Osteocyte

mature bone cells that maintain bone

Rickets (children) - disease from inadequate vitamin D

·       Bowed legs

·       Soft bones

·       Poor growth

·       Bone deformities

Osteomalacia (adults) - disease from inadequate vitamin D

·       Bone pain

·       Fragile/brittle bones

·       Frequent fractures

What is talipes

clubfoot (foot twisted medially or downward)

How is talipes treated

o   Casting (Ponseti method)

o   Bracing

o   Surgery if severe

Why is rheumatoid arthritis considered an autoimmune disease?

·       Body produces autoantibodies (RF, anti-CCP) that attack synovial membranes

·       Causes chronic inflammation → joint destruction

True or false: Osteoarthritis is “wear and tear” arthritis treated with joint replacement.

·       False.

o   Osteoarthritis is caused by wear-and-tear degeneration of cartilage,

o   Treatment includes pain control, weight loss, physical therapy,

o   Joint replacement only for severe cases.

Medical treatments for gout

·       NSAIDs

·       Colchicine

·       Allopurinol (lower uric acid)

·       Steroids

Lifestyle treatments for gout

·       Reduce alcohol (especially beer)

·       Limit red meat, shellfish

·       Hydration

·       Weight reduction

What is a pathologic fracture?

A fracture that occurs in weakened bone (tumor, osteoporosis, infection) with minimal trauma

What is osteoporosis

·       Loss of bone mass + density

·       Bones become brittle, fragile, and prone to fractures

·       Imbalance: osteoclast activity > osteoblast activity

Why is osteoporpris common in postmenopausal women?

·       Estrogen decreases sharply after menopause

·       Estrogen normally inhibits bone resorption

·       Leads to rapid bone loss → 1 in 4 affected by age 60+

How can osteoporosis be prevented

·       Weight-bearing exercise

·       Calcium + vitamin D

·       Avoid smoking/alcohol

·       Healthy body weight

How can osteoporosis be treated

·       Bisphosphonates

·       Calcitonin

·       Estrogen therapy (careful—risk-dependent)

·       Denosumab

·       Lifestyle changes

What is Marfan syndrome

Genetic disorder of connective tissue (fibrillin mutation)

Marfan syndrome clinical manifestations

o   Tall, long limbs

o   Hyperflexible joints

o   Lens dislocation

o   Aortic dilation → aneurysm risk

o   Pectus deformities

True or False: Muscular dystrophy causes muscle degeneration due to damaged nerve innervation.

·       False.

o   Muscular dystrophy causes progressive muscle degeneration due to defects in muscle structural proteins (e.g., dystrophin), not nerve damage.

Glial cell that produces myelin: oligodendrocytes

found in CNS (brain + spinal cord)

Glial cell that produces myelin: Schwann cells

found in PNS (peripheral nerves)