Lecture Exam 3

What type of epithelium lines the esophagus?

Stratified squamous non-keratinized epithelium

What makes the stomach’s muscularis externa unique?

It has three layers: inner oblique, middle circular, and outer longitudinal

What do chief cells secrete?

Pepsinogen (precursor to pepsin for protein digestion)

What do parietal cells secrete?

Hydrochloric acid and intrinsic factor

Where are Brunner’s glands found and what do they do?

Duodenum; secrete alkaline mucus to neutralize acid

Which intestinal region has the most developed plicae circulares?

Jejunum

What do Paneth cells produce?

Lysozyme and defensins (antimicrobial defense)

What is the function of the myenteric (Auerbach’s) plexus?

Controls GI motility and peristalsis

What is the function of the submucosal (Meissner’s) plexus?

Regulates glandular secretion and local blood flow

What structures are found in a portal triad?

Hepatic artery, portal vein, bile duct

Blood in a liver lobule flows toward what structure?

Central vein

What are Kupffer cells and where are they located?

Liver macrophages lining hepatic sinusoids

The anterior pituitary originates from what embryologic structure?

Rathke’s pouch (oral ectoderm)

What hormones are released by the posterior pituitary?

ADH (vasopressin) and oxytocin

What are Herring bodies?

Swellings in posterior pituitary axons that store ADH and oxytocin

What do corticotrophs in the anterior pituitary secrete?

ACTH (stimulates adrenal cortex)

What hormone do thyroid C cells produce?

Calcitonin (lowers blood calcium)

What is contained within the thyroid colloid?

Thyroglobulin (precursor to T3 and T4)

What gland contains oxyphil cells?

Parathyroid gland

What is the function of parathyroid hormone (PTH)?

Increases blood calcium by stimulating bone resorption and renal Ca²⁺ reabsorption

What does the zona glomerulosa secrete?

Aldosterone (controls sodium and water balance)

What does the zona fasciculata secrete?

Cortisol (stress hormone and glucose regulation)

What does the zona reticularis secrete?

Androgens (DHEA and related hormones)

What does the adrenal medulla secrete and what cell type produces it?

Epinephrine and norepinephrine from chromaffin cells (modified sympathetic neurons)

What type of epithelium lines most of the respiratory tract?

Pseudostratified ciliated columnar with goblet cells

What type of cartilage supports the trachea?

Hyaline cartilage (C-shaped rings)

What type of cartilage supports the epiglottis?

Elastic cartilage

What cell type replaces goblet cells in the bronchioles?

Clara (Club) cells

What do Clara (Club) cells secrete?

Surfactant-like fluid and detoxifying enzymes

What are Type I pneumocytes?

Flat cells for gas exchange covering ~95% of alveolar surface

What are Type II pneumocytes?

Cuboidal cells that secrete surfactant to reduce surface tension

What are alveolar macrophages (dust cells) responsible for?

Engulfing debris and microbes in alveoli

What structures form the blood–air barrier?

Type I pneumocyte, fused basal lamina, and capillary endothelium

What are pores of Kohn?

Openings between alveoli that equalize air pressure

What marks the start of the respiratory zone?

Respiratory bronchiole (first with alveoli)

What are the two parts of the renal corpuscle?

Glomerulus and Bowman’s capsule

What are the three components of the filtration barrier?

Fenestrated endothelium, basement membrane, podocytes

What do podocytes wrap around?

Glomerular capillaries

What does the macula densa sense?

Sodium chloride concentration in the distal tubule

What is the juxtaglomerular apparatus composed of?

Macula densa, juxtaglomerular cells, and mesangial cells

What is the main function of the proximal convoluted tubule?

Reabsorption of water, ions, and nutrients; dense microvilli brush border

What is the function of the loop of Henle?

Water and ion exchange to concentrate urine

How does the distal convoluted tubule differ histologically from the proximal?

Fewer microvilli and clearer cytoplasm

The collecting duct epithelium changes from to as it enlarges.

Cuboidal to columnar

The ureter and bladder are lined with what epithelium?

Transitional (urothelium) for stretch and recoil

The urethra differs between males and females mainly by what feature?

Male urethra is longer and part of the reproductive system

Loss of parietal cells causes what condition?

Pernicious anemia (loss of intrinsic factor → B₁₂ malabsorption)

Both posterior pituitary and adrenal medulla share what similarity?

Neural origin and hormone release into blood (neurosecretory)

The adrenal medulla is part of which nervous system branch?

Sympathetic nervous system

Which cell type is most similar in function to Clara (Club) cells?

Type II pneumocytes (both secrete surfactant-like material)

Which structures in the small intestine maximize absorption area?

Villi, microvilli, and plicae circulares

What feature identifies the large intestine microscopically?

No villi, many goblet cells, and deep crypts only

Where are Peyer’s patches found?

Ileum (immune defense of the gut)

What is the function of calcitonin?

Decreases blood calcium by inhibiting osteoclasts

What is the function of aldosterone?

Increases sodium and water reabsorption in the kidney

What type of cartilage supports the trachea?

Hyaline cartilage

What type of cartilage supports the epiglottis?

Elastic cartilage