Lecture Exam 4

Question 1

Mechanisms for inhalation:

Answer 1

• Diaphragm moves down
• Ribcage rises
• Sternum flares as external costals contract
• Thoracic and pleural cavity increase in volume
• Lung volume increases
• Air pressure in lungs decrease
• Air (gases) flows into lungs

Question 2

Mechanisms for expiration:

Answer 2

• Diaphragm rises
• Ribs and sternum are depressed as external intercostals relax
• Thoracic and pleural cavity decrease in volume
• Lung volume decreases
• Air pressure in lungs rises
• Air (gases) flows out of lungs

Question 3

Circular folds structure:

Answer 3

Permanent, transverse ridges of the mucosa and submucosa. Nearly 1 cm tall.

Question 4

Circular folds function:

Answer 4

• Increase absorptive surface area
• Force chyme to spiral thru intestinal lumen
• Slows chyme to allow for complete absorption of nutrients

Question 5

Villi structure:

Answer 5

Finger like projections of mucosa that give a velvet texture. Over 1 mm high. Covered by simple columnar epithelium made of absorptive cells called enterocytes

Question 6

Villi function:

Answer 6

Absorbs digested nutrients thru enterocytes.

Question 7

Microvilli structure:

Answer 7

Appear on apical surfaces of absorptive enterocytes. Exceptionally long and dense in small intestines.

Question 8

Microvilli function:

Answer 8

Amplify absorptive surface, their plasma membranes have enzymes that complete final stages of breakdown of nutrient molecules.

Question 9

Changes in epithelium from trachea to alveoli:

Answer 9

• Mucosal epithelium thins from pseudostratified columnar to simple columnar and then to simple cuboidal epithelium in terminal and respiratory bronchioles.
• No cilia/mucous cells in bronchioles.
• Dust particles left over get removed by macrophages in alveoli.

Question 10

Changes in hyaline cartilage from trachea to alveoli:

Answer 10

• Cartilage rings are replaced by irregular plates of cartilage as main bronchi enters lungs.
• No supportive cartilage in the tube walls by the bronchioles.

Question 11

Changes in elastic fibers from trachea to alveoli:

Answer 11

Elastin (in contrast to hyaline cartilage) occurs throughout bronchial tree, doesn’t diminish.

Question 12

Changes in smooth muscle from trachea to alveoli:

Answer 12

• layer of smooth muscle first appearing in posterior wall of trachea and continue into bronchi.
• this layer forms helical bands around smaller bronchi and bronchioles and regulate amount of air entering alveoli.
• smooth muscle thins as it reaches the terminal end of bronchiole tree and is absent around alveoli.

Question 13

Glomerulus:

Answer 13

Tuft of capillaries; part of filtration unit of kidneys

Question 14

Glomerular capsule:

Answer 14

Hollow; surrounds glomerulus; part of filtration unit of kidneys

Question 15

Renal corpuscle:

Answer 15

Occur in cortex; 1st part of nephron where filtration occurs; spherical

Question 16

Renal tubules:

Answer 16

Includes: nephron loop, distal and proximal convoluted tubules, and collecting duct.

Function: Increase the nephron length and enhances its capabilities in processing the filtrate that flows thru it.

Question 17

Proximal convoluted tubule:

Answer 17

Renal cortex; reabsorption and secretion. Cuboidal epithelial cells.

Question 18

Descending limb:

Answer 18

In the thin area there is simple squamous epithelium

Question 19

Distal convoluted tubule:

Answer 19

Renal cortex; simple cuboidal epithelium; secretion and reabsorption of ions

Question 20

Collecting ducts:

Answer 20

Receive urine from several nephrons and runs straight thru the cortex into the deep medulla.

Question 21

Describe the hormonal regulation of urine concentration:

Answer 21

When solute concentrations in filtrate fall below a certain level, the cells of the macula densa signal granular cells to secrete renin.

Renin initiates chemical sequence which eventually leads to secretion of the hormone aldosterone from the adrenal cortex.

Question 22

Name 3 (urine) hormones and their functions:

Answer 22

• Renin: eventually cause an increase in blood pressure.
• Aldosterone: increases sodium resorption from distal convoluted tubules, which increases blood-solute concentration.
• Antidiuretic hormone (ADH): retain water in body and constrict blood vessels.